text:
Office of Scientific and Technical Information
Killing Bacteria
NLE Websites -- All DOE Office Websites (Extended Search)
Killing Bacteria Killing Bacteria Name: alli Location: N/A Country: N/A Date: N/A Question: What kills more bacteria for the recommended cooking time in a microwave and a conventional oven? Replies: I hope I understand your question. The time it takes to get your food done is sufficient to kill all bacteria--but not the spores of certain bacteria--both by microwave cooking and in a conventional oven. The spores are not a problem when the food is consumed directly but can be a health hazard when food is bottled and stored. See recommendations at http://www.cfia-acia.agr.ca/english/corpaffr/foodfacts/perfrine.shtml on Clostridium, one of the most dangerous causes of food poinsoning. Or visit the display on Food Safety in the Virtual Museum of Bacteria (www.bacteriamuseum.org) at www.bacteriamuseum.org/niches/foodsafety/foodsafety.shtml
DOE Patents (OSTI)
A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.
Thompson, W.I.
Filament wound structure and method
The present invention relates to a filament wound spherical structure comprising a plurality of filament band sets disposed about the surface of a mandrel with each band of each set formed of a continuous filament circumferentially wound about the mandrel a selected number of circuits and with each circuit of filament being wound parallel to and contiguous with an immediate previously wound circuit. Each filament band in each band set is wound at the same helix angle from the axis of revolution of the mandrel and all of the bands of each set are uniformly distributed about the mandrel circumference. The pole-to-equator wall thickness taper associated with each band set, as several contiguous band sets are wound about the mandrel starting at the poles, is accumulative as the band sets are nested to provide a complete filament wound sphere of essentially uniform thickness.
Dritt, William S. (Oak Ridge, TN); Gerth, Howard L. (Knoxville, TN); Knight, Jr., Charles E. (Knoxville, TN); Pardue, Robert M. (Knoxville, TN)
Mode trap
This report discusses a mode trap to trap and absorb transverse modes formed by a beam in a linear accelerator includes a waveguide having a multiplicity of electrically conductive (preferably copper) irises and rings, each iris and ring including an aperture, and the irises and rings being stacked in a side-by-side, alternating fashion such that the apertures of the irises and rings are concentrically aligned. An absorbing material layer such as a dielectric is embedded in each iris and ring, and this absorbing material layer encircles, but is circumferentially spaced from its respective aperture. Each iris and ring includes a plurality of circumferentially spaced slots around it`s aperture and extending radially out toward it`s absorbing material layer.
Chojnacki, E.P.
Wound tube heat exchanger
What is disclosed is a wound tube heat exchanger in which a plurality of tubes having flattened areas are held contiguous adjacent flattened areas of tubes by a plurality of windings to give a double walled heat exchanger. The plurality of windings serve as a plurality of effective force vectors holding the conduits contiguous heat conducting walls of another conduit and result in highly efficient heat transfer. The resulting heat exchange bundle is economical and can be coiled into the desired shape. Also disclosed are specific embodiments such as the one in which the tubes are expanded against their windings after being coiled to insure highly efficient heat transfer.
Ecker, Amir L. (Duncanville, TX)
Marginally outer trapped surfaces in higher dimensions
E-Print Network (OSTI)
We review the basic setup of Kaluza-Klein theory, namely a 5-dimensional vacuum with a cyclic isometry, which corresponds to Einstein-Maxwell-dilaton theory in 4-dimensional spacetime. We first recall the behaviour of Killing horizons and its generators under bundle lift and projection. We then show that the property of compact surfaces of being (stably) marginally trapped is preserved under lift and projection provided the appropriate ("Pauli-") conformal scaling is used for the spacetime metric. We also discuss and compare recently proven area inequalities for stable axially symmetric 2-dimensional and 3-dimensional marginally outer trapped surfaces.
Tim-Torben Paetz; Walter Simon
Interaction of trapped ions with trapped atoms
In this thesis, I present results from two Paul-trap based ion traps carried out in the Vuleti? laboratory: the Atom-Ion trap for collision studies between cold atoms and cold ions, and the Cavity-Array trap for studying ...
Grier, Andrew T. (Andrew Todd)
An improved linear-flow cold trap is designed for highvacuum applications such as mitigating back migration of diffusion pump oil moiecules. A central pot of liquid nitrogen is nested within and supported by a surrounding, vertical, helical coil of metai sheet, all enveloped by a larger, upright, cylindrical, vacuum vessel. The vertical interstices between successive turns of the coil afford lineal, axial, high-vacuum passages between open mouths at top and bottom of said vessel, while the coil, being cold by virtue of thermal contact of its innermost turn with the nitrogen pot, affords expansive proximate condensation surfaces. (AEC)
Milleron, N.
The killing consensus : homicide detectives, police that kill and organized crime in S�o Paulo, Brazil
Policing is widely understood, empirically and theoretically, as a core function of the state. Much of the knowledge presumes that police are the only body that may kill and arbitrate killing, routinely and without retaliation ...
Willis, Graham Arthur Neill, 1979-
Physics of Wound Healing I: Energy Considerations
Wound healing is a complex process with many components and interrelated processes on a microscopic level. This paper addresses a macroscopic view on wound healing based on an energy conservation argument coupled with a general scaling of the metabolic rate with body mass M as M^{\\gamma} where 0 monitor the status of a wound. 2) We find that the time-scale for wound healing is a factor 1/(1 -{\\gamma}) longer than the average internal timescale for producing new material filling the wound cavity in corresondence with that it usually takes weeks rather than days to heal a wound. 3) The model gives a prediction for the maximum wound mass which can be generated in terms of measurable quantities related to wound status. We compare our model predictions to experimental results for a range of different wound conditions (healthy, lean, diabetic and obses...
Apell, S Peter; Papazoglou, Elisabeth S; Pizziconi, Vincent
Acceleration Of Wound Healing Ny Photodynamic Therapy
Disclosed is a method for accelerating wound healing in a mammal. The method includes identifying an unhealed wound site or partially-healed wound site in a mammal; administering a photosensitizer to the mammal; waiting for a time period wherein the photosensitizer reaches an effective tissue concentration at the wound site; and photoactivating the photosensitizer at the wound site. The dose of photodynamic therapy is selected to stimulate the production of one or more growth factor by cells at the wound site, without causing tissue destruction.
Hasan, Tayyaba (Arlington, MA); Hamblin, Michael R. (Revere, MA); Trauner, Kenneth (Sacramento, CA)
Microfabricated Ion Traps
Ion traps offer the opportunity to study fundamental quantum systems with high level of accuracy highly decoupled from the environment. Individual atomic ions can be controlled and manipulated with electric fields, cooled to the ground state of motion with laser cooling and coherently manipulated using optical and microwave radiation. Microfabricated ion traps hold the advantage of allowing for smaller trap dimensions and better scalability towards large ion trap arrays also making them a vital ingredient for next generation quantum technologies. Here we provide an introduction into the principles and operation of microfabricated ion traps. We show an overview of material and electrical considerations which are vital for the design of such trap structures. We provide guidance in how to choose the appropriate fabrication design, consider different methods for the fabrication of microfabricated ion traps and discuss previously realized structures. We also discuss the phenomenon of anomalous heating of ions within ion traps, which becomes an important factor in the miniaturization of ion traps.
Marcus D. Hughes; Bjoern Lekitsch; Jiddu A. Broersma; Winfried K. Hensinger
Superconducting microfabricated ion traps
We fabricate superconducting ion traps with niobium and niobium nitride and trap single [superscript 88]Sr ions at cryogenic temperatures. The superconducting transition is verified and characterized by measuring the ...
Wang, Shannon Xuanyue
Ion trap simulation tools.
Science Conference Proceedings (OSTI)
Ion traps present a potential architecture for future quantum computers. These computers are of interest due to their increased power over classical computers stemming from the superposition of states and the resulting capability to simultaneously perform many computations. This paper describes a software application used to prepare and visualize simulations of trapping and maneuvering ions in ion traps.
Hamlet, Benjamin Roger
Steam Trap Application
The effective application of steam traps encompasses three primary areas which are the selection and sizing, the installation, and the monitoring of the steam trapping system. Proper application of steam traps will improve production rates, product quality, and reduce energy and maintenance costs.
Murphy, J. J.
Timelike Killing Fields and Relativistic Statistical Mechanics
For spacetimes with timelike Killing fields, we introduce a "Fermi-Walker-Killing" coordinate system and use it to prove a Liouville Theorem for an appropriate volume element of phase space for a statistical mechanical system of particles. We derive an exact relativistic formula for the Helmholtz free energy of an ideal gas and compare it, for a class of spacetimes, to its Newtonian analog, derived both independently and as the Newtonian limit of our formula. We also find the relativistic thermodynamic equation of state. Specific examples are given in Kerr spacetime.
David Klein; Peter Collas
HIV transcription is induced with cell killing
SciTech Connect
In this report, we demonstrate that this induction of HIV-LTR transcription occurs when stably transfected HeLa cells are exposed to agents which mediate cell killing, such as UV radiation, electroporation of sucrose buffer, prolonged heating, and low and high pH. Cells cultured following UV exposure demonstrated a peak in CAT expression that is evident in viable (but not necessarily cell division-competent) cells 24 h after exposure; this inductive response continued until at least 72 h after exposure. HIV-LTR induction was dose-dependent, and the amount of CAT transcription induced was correlated with the amount of cell killing that occurred in the culture.
Woloschak, G.E.; Schreck, S.; Chang-Liu, Chin-Mei [Argonne National Lab., IL (United States); Panozzo, J.; Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)
We fabricate superconducting ion traps with niobium and niobium nitride and trap single 88Sr ions at cryogenic temperatures. The superconducting transition is verified and characterized by measuring the resistance and critical current using a 4-wire measurement on the trap structure, and observing change in the rf reflection. The lowest observed heating rate is 2.1(3) quanta/sec at 800 kHz at 6 K and shows no significant change across the superconducting transition, suggesting that anomalous heating is primarily caused by noise sources on the surface. This demonstration of superconducting ion traps opens up possibilities for integrating trapped ions and molecular ions with superconducting devices.
Shannon X. Wang; Yufei Ge; Jaroslaw Labaziewicz; Eric Dauler; Karl Berggren; Isaac L. Chuang
Ion traps offer the opportunity to study fundamental quantum systems with high level of accuracy highly decoupled from the environment. Individual atomic ions can be controlled and manipulated with electric fields, cooled to the ground state of motion with laser cooling and coherently manipulated using optical and microwave radiation. Microfabricated ion traps hold the advantage of allowing for smaller trap dimensions and better scalability towards large ion trap arrays also making them a vital ingredient for next generation quantum technologies. Here we provide an introduction into the principles and operation of microfabricated ion traps. We show an overview of material and electrical considerations which are vital for the design of such trap structures. We provide guidance in how to choose the appropriate fabrication design, consider different methods for the fabrication of microfabricated ion traps and discuss previously realized structures. We also discuss the phenomenon of anomalous heating of ions with...
Hughes, Marcus D; Broersma, Jiddu A; Hensinger, Winfried K
Killingly, Connecticut: Energy Resources | Open Energy Information
Open Energy Info (EERE)
Killingly, Connecticut: Energy Resources Killingly, Connecticut: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 41.8122401°, -71.8334145° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":41.8122401,"lon":-71.8334145,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Evaluating Steam Trap Performance
Laboratory tests were conducted on several types of steam traps at Holston Defense Corporation in Kingsport, Tennessee. Data from these tests, which determined their relative efficiencies, were used in performing economic analyses to determine their equivalent uniform annual cost (EUAC). The comparison was made using a computer program written for the Apple II computer to evaluate overall steam trap economics. This program calculates the EUAC for any steam trap based on 12 input variables including capital, maintenance and steam costs, interest rate and trap life. After determinIng the EUAC, the program will perform sensitivity analyses on any of the twelve variables. (This computer program is available from the author.) This study shows that inverted bucket traps have lower EUAC's under more conditions than other types of traps. Also, this study shows that live steam loss is the heaviest contributor to the annual operating cost of any steam trap and that maintenance frequency and repair cost are also more important than a trap's first cost.
Fuller, N. Y.
Nonlinear integrable ion traps
Quadrupole ion traps can be transformed into nonlinear traps with integrable motion by adding special electrostatic potentials. This can be done with both stationary potentials (electrostatic plus a uniform magnetic field) and with time-dependent electric potentials. These potentials are chosen such that the single particle Hamilton-Jacobi equations of motion are separable in some coordinate systems. The electrostatic potentials have several free adjustable parameters allowing for a quadrupole trap to be transformed into, for example, a double-well or a toroidal-well system. The particle motion remains regular, non-chaotic, integrable in quadratures, and stable for a wide range of parameters. We present two examples of how to realize such a system in case of a time-independent (the Penning trap) as well as a time-dependent (the Paul trap) configuration.
Nagaitsev, S.; /Fermilab; Danilov, V.; /SNS Project, Oak Ridge
Workshop on Ion Trap Technology
... optical components, conventional and microfabricated ion traps, and classical control ... will bring together experts on trapped-ion physics, laser optics ...
Steam trap monitor
A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (a hot finger) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellow in providing an indication of total energy (steam + condensate) of the system. Processing means coupled to and responsive to outputs from the hot and cold fingers subtracts the former from the latter to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning. 2 figs.
Ryan, M.J.
'Sentinels' seeking opportunities for wounded veterans
11302012 'Sentinels' seeking opportunities for wounded veterans Linda A Lucchetti, LLNL, (925) 422-5815, firstname.lastname@example.com Printer-friendly Roy Warner of the Lab's Veterans...
Carbon Dioxide Emissions From Vegetation-Kill Zones Around The...
of Long Valley caldera California was performed to evaluate the premise that gaseous and thermal anomalies are related to renewed intrusion of magma. Some kill sites are...
Asymmetric ion trap
An ion trap having two end cap electrodes disposed asymmetrically about a center of a ring electrode. The inner surface of the end cap electrodes are conformed to an asymmetric pair of equipotential lines of the harmonic formed by the application of voltages to the electrodes. The asymmetry of the end cap electrodes allows ejection of charged species through the closer of the two electrodes which in turn allows for simultaneously detecting anions and cations expelled from the ion trap through the use of two detectors charged with opposite polarity.
Barlow, Stephan E. (Richland, WA); Alexander, Michael L. (Richland, WA); Follansbee, James C. (Pasco, WA)
Venus Fly Trap Experiment
Venus Fly Trap Experiment Venus Fly Trap Experiment Name: Jeremy Bailey Status: N/A Age: N/A Location: N/A Country: N/A Date: N/A Question: My name is Jeremy Bailey, and I am a student of Dorseyville Middle School. I have been working on a science project about Venus' Fly Traps. A recent addition to the project involved designing an experiment about something I found interesting about them. However, I don't know where to get them or how to grow them in the moderate climate of Pittsburgh. Also, I don't know how a successful experiment could be designed. Replies: Jeremy, I believe Venus Fly traps can be found 'in the wild' in the coastal floodplain of the Carolinas. As far as where to buy them, look in the phonebook yellow pages under plants or houseplants and do some calling. I live in eastern Pennsylvania, and over here they even sell them in hardware stores like Hechinger's and Home Depot (in their garden departments). I don't think you will have luck trying to grow them outside, our winters here are a bit too harsh for them. From what I recall they require substantial moisture and more moderate climes. You might try looking for houseplant books at your local library for more detailed information.
A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (the combination of a hot finger and thermocouple well) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellows in providing an indication of total energy (steam+condensate) of the system. Processing means coupled to and responsive to outputs from the thermocouple well hot and cold fingers subtracts the condensate energy as measured by the hot finger and thermocouple well from the total energy as measured by the cold finger to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning.
Ryan, Michael J. (Plainfield, IL)
Although tidally locked habitable planets orbiting nearby M-dwarf stars are among the best astronomical targets to search for extrasolar life, they may also be deficient in volatiles and water. Climate models for this class of planets show atmospheric transport of water from the dayside to the nightside, where it is precipitated as snow and trapped as ice. Since ice only slowly flows back to the dayside upon accumulation, the resulting hydrological cycle can trap a large amount of water in the form of nightside ice. Using ice sheet dynamical and thermodynamical constraints, I illustrate how planets with less than about a quarter the Earth's oceans could trap most of their surface water on the nightside. This would leave their dayside, where habitable conditions are met, potentially dry. The amount and distribution of residual liquid water on the dayside depend on a variety of geophysical factors, including the efficiency of rock weathering at regulating atmospheric CO{sub 2} as dayside ocean basins dry up. Water-trapped worlds with dry daysides may offer similar advantages as land planets for habitability, by contrast with worlds where more abundant water freely flows around the globe.
Menou, Kristen [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)
Nuclear Physics with trapped
Nuclear Physics with trapped atoms and ions #12;2/2/2013Dan Melconian #12;2/2/2013Dan Melconian Outline · Scope and applications of nuclear physics precision frontier compliments LHC properties and aquifers in the Sahara #12;2/2/2013Dan Melconian What is Nuclear Physics? · Began with the study
Boas, Harold P.
Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens
The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.
Daniel P. Molloy
HIV transcription is induced with some forms of cell killing
Using HeLa cells stably transfected with an HIV-LTR-CAT construct`, we demonstrated a peak in CAT induction that occurs in viable (but not necessarily cell-division-competent) cells 24 h following exposure to some cell-killing agents. {Gamma} rays were the only cell-killing agent which did not induce HIV transcription; this can be attributed to the fact that {gamma}-ray-induced apoptotic death requires function p53, which is missing in HeLa cells. For all other agents, HIV-LTR induction was dose-dependent and correlated with the amount of cell killing that occurred in the culture.
Woloschak, G.E. [Argonne National Lab., IL (United States); Schreck, S. [Argonne National Lab., IL (United States)][South Carolina Univ., Columbia, SC (United States). Dept. of Chemistry; Panozzo, J. [Loyola Univ. Medical Center, Maywood, IL (United States); Chang-Liu, C.-M. [Argonne National Lab., IL (United States); Libertin, C.R. [Loyola Univ. Medical Center, Maywood, IL (United States)
Kill-a-Watt Contest at UCF | Department of Energy
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
Kill-a-Watt Contest at UCF Kill-a-Watt Contest at UCF Kill-a-Watt Contest at UCF April 2, 2010 - 5:16pm Addthis The University of Central Florida has created an innovative way to save energy and money on campus through a new dorm-based competition called "Kill-a-Watt". Students representing campus residence halls compete against each other to achieve energy savings and can receive up to $200 in scholarships. Watch how former DOE intern and current UCF DOE Campus Ambassador, Chris Castro, is spearheading this exciting effort and learn more about energy saving tips that students find useful like proper thermostat set points and reducing plug load. Read the DoE's press release about the video. Addthis Related Articles University of Central Florida Students' Energy Saving Work Showcased in New
The effect of acemannan immunostimulant on a wound healing model
Acemannan is a complex carbohydrate composed primarily of acetylated mannans and galacturonic acid. It is prepared by sequential ethanol precipitation of the A loe vera L. leaf gel. Acemannan has several important therapeutic properties including acceleration of wound healing, reduction of inflammation, immunomodulation, and antitumor effects. The process by which acemannan induces these therapeutic properties is not completely understood. This study was designed to investigate the manner by which acemannan accelerates wound healing by examining wound fluid and granulation tissue. The wire mesh wound chamber allows for sequential analysis of the wound fluid, provides a physical barrier between new granulation tissue and preexistent tissue, and the contents of the chamber proceed naturally through the healing process. Wound chambers were surgically implanted subcutaneously in the lateral dorsal area then injected with either 2 mg/ml acemannan or saline as a control. Wound fluid was extracted every other day for fourteen days and at the end of the treatment period the wound chambers were removed and the tissue was extracted. Wound fluid was analyzed for nitric oxide, metalloproteinase activity, cell proliferative effects, protein composition and binding proteins. Wound chamber tissue was analyzed both histologically and chemically for collagen content. Total protein and nitric oxide levels were not significantly different between acemannan and control. Acemannan treated wound fluid contained a higher percentage of total neutrophils and neutrophils having degenerative morphological characteristics. Acemannan treated wound fluid contained a lower percentage of macrophages than the control. The most significant difference was observed in collagen content of chamber granulation tissue. Tissue from treated chambers contained more collagen; as meaned by both biochemical and morphological analyses. Studies were conducted to determine the effects of exposure to wound fluid on fibroblasts and endothelial cells. Acemannan treated wound fluid induced significantly greater fibroblast proliferation and cytoplasmic spreading in endothelial cells. These studies suggest that acemannan accelerates the rate of wound healing through increased collagen deposition, stimulation of tissue repair cells, and modulation of inflammatory cells.
Kennon, Katherine Ann
DNA Separation Using Photoelectrophoretic Traps
In our recent publications we presented a design that allows formation of highly localized and optically controlled electrophoretic traps. 1,2 We demonstrated that electrophoretic traps can be utilized for biomolecule photoconcentration, optically directed transport, and separation by size. 1,2 In the current publication we suggest a hybrid design for biomolecule separation which implements electrophoretic traps in tandem with well-established electrophoretic techniques. We perform Monte Carlo simulations that demonstrate that the resolution of well-established electrophoretic techniques can be greatly enhanced by introducing photoelectrophoretic traps.
Braiman, Avital [ORNL; Thundat, Thomas George [ORNL; Rudakov, Fedor M [ORNL
Electron Trapping by Molecular Vibration
Electron Trapping by Molecular Vibration Print In photoelectron spectroscopy experiments performed at the ALS, a group of researchers has found that electronic transitions normally...
Laser Cooling of Trapped Ions.
... period, so it can be assumed to give an in- stantaneous impulse to the ... In sympathetic laser cooling, two different ion species are loaded into a trap. ...
Theory and application of planar ion traps
In this thesis, we investigate a new geometry of Paul trap with electrodes in a plane. These planar ion traps are compatible with modern silicon microfabrication, and can be scaled up to large arrays with multiple trapping ...
Pearson, Christopher Elliott
First Attempts at Antihydrogen Trapping in ALPHA
The ALPHA apparatus is designed to produce and trap antihydrogen atoms. The device comprises a multifunction Penning trap and a superconducting, neutral atom trap having a minimum-B configuration. The atom trap features an octupole magnet for transverse confinement and solenoidal mirror coils for longitudinal confinement. The magnetic trap employs a fast shutdown system to maximize the probability of detecting the annihilation of released antihydrogen. In this article we describe the first attempts to observe antihydrogen trapping.
Andresen, G. B.; Bowe, P. D.; Hangst, J. S. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A. J.; Jenkins, M. J.; Joergensen, L. V.; Madsen, N.; Werf, D. P. van der [Department of Physics, Swansea University, Swansea SA2 8PP (United Kingdom); Bray, C. C.; Chapman, S.; Fajans, J.; Povilus, A.; Wurtele, J. S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Cesar, C. L.; Lambo, R.; Silveira, D. M. [Instituto de Fisica Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Fujiwara, M. C. [TRIUMF, 4004 Wesbrook Mall, Vancouver BC, V6T 2A3 (Canada)] (and others)
Trapped Quintessential Inflation
Quintessential inflation is studied using a string modulus as the inflaton - quintessence field. The modulus begins its evolution at the steep part of its scalar potential, which is due to non-perturbative effects (e.g. gaugino condensation). It is assumed that the modulus crosses an enhanced symmetry point (ESP) in field space. Particle production at the ESP temporarily traps the modulus resulting in a brief period of inflation. More inflation follows, due to the flatness of the potential, since the ESP generates either an extremum (maximum or minimum) or a flat inflection point in the scalar potential. Eventually, the potential becomes steep again and inflation is terminated. After reheating the modulus freezes due to cosmological friction at a large value, such that its scalar potential is dominated by contributions due to fluxes in the extra dimensions or other effects. The modulus remains frozen until the present, when it can become quintessence and account for the dark energy necessary to explain the observed accelerated expansion.
J. C. Bueno Sanchez; K. Dimopoulos
Timelike Killing Fields and Relativistic Statisti-cal Mechanics
-time, and this corresponds to a Newtonian gas subject to gravitational, tidal, and in some instances "centrifugal forces gas and compare it, for a class of spacetimes, to its Newtonian analog, derived both independently examples are given in Kerr spacetime. KEY WORDS: Statistical mechanics; Relativistic ideal gas; Killing
Klein, David
Inspect and Repair Steam Traps
This revised ITP tip sheet on inspecting and repairing steam traps provide how-to advice for improving industrial steam systems using low-cost, proven practices and technologies.
Not Available
Electronic Trap States in Methanofullerenes
The trap states in three fullerene derivatives, namely PC61BM ([6,6]-phenyl C61 butyric acid methyl ester), bisPC61BM (bis[6,6]-phenyl C61 butyric acid methyl ester) and PC71BM ([6,6]-phenyl C71 butyric acid methyl ester), are investigated by thermally stimulated current measurements (TSC). Thereby, the lower limit of the trap densities for all studied methanofullerenes exhibits values in the order of 10^22 m^-3 with the highest trap density in bisPC61BM and the lowest in PC61BM. Fractional TSC measurements on PC61BM reveal a broad trap distribution instead of discrete trap levels with activation energies ranging from 15 meV to 270 meV and the maximum at about 75 meV. The activation energies of the most prominent traps in the other two fullerene derivatives are significantly higher, being at 96 meV and 223 meV for PC71BM and 184 meV for bisPC61BM, respectively. The influence of these findings on the performance of organic solar cells is discussed.
Julia Schafferhans; Carsten Deibel; Vladimir Dyakonov
Electron Trapping by Molecular Vibration Print Electron Trapping by Molecular Vibration Print In photoelectron spectroscopy experiments performed at the ALS, a group of researchers has found that electronic transitions normally thought to be forbidden can in fact be excited in conjunction with certain types of molecular vibrations. Specifically, they found that when the symmetry of a linear triatomic molecule is broken by asymmetric vibrational modes, photoelectrons can become temporarily trapped by the molecule before ultimately escaping, giving rise to a broad feature in the photoelectron spectrum known as a shape resonance. This process represents a novel type of symmetry-breaking phenomenon that has not been observed previously but appears to be widespread. Such coupling between electronic motion and nuclear motion becomes increasingly important as scientists learn more about the geometry and dynamics of novel chemical structures such as those found in nanodevices and transient chemical species, and the results have implications for studies that use photoelectron spectroscopy as a diagnostic tool.
Electron Trapping by Molecular Electron Trapping by Molecular Vibration Electron Trapping by Molecular Vibration Print Wednesday, 27 April 2005 00:00 In photoelectron spectroscopy experiments performed at the ALS, a group of researchers has found that electronic transitions normally thought to be forbidden can in fact be excited in conjunction with certain types of molecular vibrations. Specifically, they found that when the symmetry of a linear triatomic molecule is broken by asymmetric vibrational modes, photoelectrons can become temporarily trapped by the molecule before ultimately escaping, giving rise to a broad feature in the photoelectron spectrum known as a shape resonance. This process represents a novel type of symmetry-breaking phenomenon that has not been observed previously but appears to be widespread. Such coupling between electronic motion and nuclear motion becomes increasingly important as scientists learn more about the geometry and dynamics of novel chemical structures such as those found in nanodevices and transient chemical species, and the results have implications for studies that use photoelectron spectroscopy as a diagnostic tool.
Trapped-flux superconducting memory
A memory cell based on trapped flux in superconductors has been built and tested. The cell is constructed entirely by vacuum evaporation of thin films and can be selected by coincident current or by other techniques, with drive-current requirements less ...
J. W. Crowe
May 28, 2010: Chu helps oversee BP's "top kill" efforts | Department of
May 28, 2010: Chu helps oversee BP's "top kill" efforts May 28, 2010: Chu helps oversee BP's "top kill" efforts May 28, 2010: Chu helps oversee BP's "top kill" efforts May 28, 2010: Chu helps oversee BP's "top kill" efforts May 28, 2010 Secretary Chu concludes several days in Houston monitoring the "top kill" attempt to stop the oil well leak in the Gulf of Mexico, analyzing the data as it comes in and helping to develop strategies to give it the best chances of success. In the days leading up to the top kill attempt, the Secretary and his team of scientists provided expert advice and technical support to test the assumptions behind BP's work and to offer analytical rigor. When diagnostic and pressure tests were conducted to inform BP's decision on whether to attempt the top kill, the Secretary and
Long-Wave Trapping by Oceanic Ridges
Long waves are affected by bottom topography and under certain conditions may be trapped along topographical contours which then act as wave guides transmitting wave energy for great distances with little loss. This study examines waves trapped ...
Richard Paul Shaw; Wayne Neu
A Neutrally Buoyant, Upper Ocean Sediment Trap
The authors have designed and deployed a neutrally buoyant sediment trap (NBST) intended for use in the upper ocean. The aim was to minimize hydrodynamic flow interference by making a sediment trap that drifted freely with the ambient current. ...
James R. Valdes; James F. Price
Inertial measurement via dynamics of trapped particles
We describe theoretical and practical aspects of the particle trap as an inertial sensor. The insight motivating this approach is that a trapped particle acts like a mass on a spring, but the restoring forces are provided ...
Post, E. Rehmi, 1966-
Determination of Hydrogen Peak Temperatures and Trapping ...
Presentation Title, Determination of Hydrogen Peak Temperatures and Trapping Energies of Various Lattice Defects In Iron Using Thermal Desorption�...
Control instrumentation for wellheads and mud-kill systems. [Indonesia
This paper describes the instrumentation and control systems used on the wellheads and mud-kill systems at the Mobil Oil Arun natural gas field, situated onshore in the province of Aceh, North Sumatra, Indonesia. The reservoir is a carbonate reef containing an estimated 15 Tcf (0.42 X 10/sup 12/ m/sup 3/) gas at approximately 7,000 psig (48 263 kPa) and 360/sup 0/F (182/sup 0/C). The wellstream from the field is separated into natural gas, condensate liquid, and water. The gas and condensate are then shipped through separate pipelines to the Arun liquefied natural gas (LNG) facility at Lho' Seumawe, about 40 mi (25 km) away on the northeastern coast of Sumatra. After liquefaction the LNG is shipped by tanker to Japan. The field was discovered in 1971 and became operational in 1977. The LNG delivery contract complied with the Japanese calls for regular delivery; thus continuity of supply to the LNG plant was of paramount importance for meeting transportation and supply schedules. Two actual blowouts in the Arun field have provided valuable experience in evaluating both equipment and systems in terms of design, reliability, and application for this type of field service. This paper concentrates on the design and installation of the control systems associated with the wellhead and mud-kill systems and highlights the problems encountered during the past five years.
Giles, A.J.
Capturing Energy Savings with Steam Traps
This paper will discuss the energy savings potential of steam traps and present the energy, economic, and environmental reason why an active steam trap maintenance program is good for the company's bottom line. Several case studies will be discussed to demonstrate the merits of steam trap technology.
Bockwinkel, R. G.; French, S. A.
The Elimination of Steam Traps
How would you like to have a share of $154,000,000,000 a year? According to the Department of Energy that is roughly what was spent for creating steam in 1978. Steam generation accounts for fully one half of the industrial and commercial energy dollar. That figure could be reduced by 10-20% or more by the simple elimination of steam traps. Recent engineering developments show that steam traps can be eliminated. Documented results demonstrate that the retrofitting of existing facilities to alternative methods of condensate removal is simple and economically feasible, with paybacks of less than 12 months. Advantages obtained in the first year remain consistent for several years after conversion with virtual elimination of maintenance.
Dickman, F.
Transparent ion trap with integrated photodetector
Fluorescence collection sets the efficiency of state detection and the rate of entanglement generation between remote trapped ion qubits. Despite efforts to improve light collection using various optical elements, solid angle capture is limited to ~10% for implementations that are scalable to many ions. We present an approach based on fluorescence detection through a transparent trap using an integrated photodetector, combining collection efficiency approaching 50% with scalability. We microfabricate transparent surface traps with indium tin oxide and verify stable trapping of single ions. The fluorescence from a cloud of ions is detected using a photodiode sandwiched with a transparent trap.
Amira M. Eltony; Shannon X. Wang; Gleb M. Akselrod; Peter F. Herskind; Isaac L. Chuang
Eltony, Amira M; Akselrod, Gleb M; Herskind, Peter F; Chuang, Isaac L
Green functions and Euclidean fields near the bifurcate Killing horizon
We approximate a Euclidean version of a D+1 dimensional manifold with a bifurcate Killing horizon by a product of a two-dimensional Rindler space and a D-1 dimensional manifold M. We obtain approximate formulas for the Green functions. We study the behaviour of Green functions near the horizon and their dimensional reduction. We show that if M is compact then the massless minimally coupled quantum field contains a zero mode which is a conformal invariant free field on R^2. Then, the Green function near the horizon can be approximated by the Green function of the two-dimensional quantum field theory. The correction term is exponentially small away from the horizon. If the volume of a geodesic ball is growing to infinity with its radius then the Green function cannot be approximated by a two-dimensional one.
Z. Haba
Direct-energy-regenerated particulate trap technology. Final report
DOE Green Energy (OSTI)
The objective of this CRADA between Lockheed Martin and Cummins Engine Company was to develop fiber-reinforced silicon carbide (SiC) composite materials for use as diesel engine particulate traps. Chemical vapor deposition techniques were used to partially densify and rigidize a thin fibrous substrate and produce the porous SiC- based filter. Microwave energy was used to directly couple to the deposited SiC to uniformly heat the filter and oxidize the collected carbon particulates. For commercial usage particulate traps must: (1) filter carbon particulates from a high temperature diesel exhaust at an acceptably low backpressure, (2) survive thousands of thermal transients due to regeneration or cleaning of the filter by oxidizing the collected carbon, (3) be durable and reliable over the expected life of the filter (300,000 miles or 10,000 hours), and (4) provide a low overall operating cost which is competitive with other filtering techniques. The development efforts performed as part of this CRADA have resulted in a very promising new technology for Cummins Engine Company. Ceramic fiber based filter papers were developed at Fleetguard, Inc., (a Cummins Subsidiary) and used to produce the spiral wound, corrugated filter cartridges. Optimized SiC coatings were developed at Lockheed Martin which couple with 2.45 GHz microwaves. Prototype particulate filter cartridges fabricated at Fleetguard and rigidized at Lockheed Martin performed well in single cylinder engine tests at Cummins. These prototype filters obtained filtering efficiencies greater than 80% at acceptably low backpressures and could be successfully headed and regenerated using a conventional in-home microwave oven.
Stinton, D.P.; Janney, M.A. [Oak Ridge National Lab., TN (United States); Yonushonis, T.M.; McDonald, A.C.; Wiczynski, P.D. [Cummins Engine Co., Inc., Columbus, IN (United States); Haberkamp, W.C. [Fleetguard, Inc. (United States)
Texas A&M Penning Trap Facility - Design of the Measurement Trap
A tandem Penning trap facility has been designed and is under construction at the Texas A&M University Cyclotron Institute (TAMU-TRAP). The initial experimental program will be the study of correlation parameters for T=2 superallowed beta-delayed proton emitters. The measurement trap is a unique large-bore optimized 5-electrode cylindrical Penning trap, which features a 90 mm free radius, larger than in any existing Penning trap. This novel geometry allows for full radial containment of decay products of interest. The trap has also been designed to exhibit a "tunable" and "orthogonalized" geometry, which is useful for alternate experiments.
Mehlman, M; Shidling, P D
M. Mehlman; D. Melconian; P. D. Shidling
Trapping Rydberg Atoms in an Optical Lattice
Rubidium Rydberg atoms are laser excited and subsequently trapped in a one-dimensional optical lattice (wavelength 1064 nm). Efficient trapping is achieved by a lattice inversion immediately after laser excitation using an electro-optic technique. The trapping efficiency is probed via analysis of the trap-induced shift of the two-photon microwave transition 50S{yields}51S. The inversion technique allows us to reach a trapping efficiency of 90%. The dependence of the efficiency on the timing of the lattice inversion and on the trap laser power is studied. The dwell time of 50D{sub 5/2} Rydberg atoms in the lattice is analyzed using lattice-induced photoionization.
Anderson, S. E.; Younge, K. C.; Raithel, G. [FOCUS Center, Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
Trapping and Measuring Charged Particles in Liquids
Genome sequencing especially benefits from the nanoscale approach. The trap is a three-layer, three-dimensional crossing metal/insulator structure.
Using molecular dynamics simulations, the researchers found that particles are trapped in liquid environments when appropriate AC/DC electric fields ...
Town of Kill Devil Hills - Wind Energy Systems Ordinance | Department of
Town of Kill Devil Hills - Wind Energy Systems Ordinance Town of Kill Devil Hills - Wind Energy Systems Ordinance Town of Kill Devil Hills - Wind Energy Systems Ordinance < Back Eligibility Agricultural Commercial Industrial Institutional Local Government Nonprofit Residential Schools Savings Category Wind Buying & Making Electricity Program Info State North Carolina Program Type Solar/Wind Permitting Standards Provider Kill Devil Hills Planning and Inspections In October 2007, the town of Kill Devil Hills adopted an ordinance to regulate the use of wind-energy systems. The ordinance directs any individual or organization wishing to install a wind-energy system to obtain a zoning permit from the town planning board. '''Size Requirements:''' Wind turbine towers are restricted to a height of 80 feet with a maximum rotor size of 23 feet in diameter. The combined
Carbon Dioxide Emissions From Vegetation-Kill Zones Around The Resurgent
Dioxide Emissions From Vegetation-Kill Zones Around The Resurgent Dioxide Emissions From Vegetation-Kill Zones Around The Resurgent Dome Of Long Valley Caldera, Eastern California, Usa Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Carbon Dioxide Emissions From Vegetation-Kill Zones Around The Resurgent Dome Of Long Valley Caldera, Eastern California, Usa Details Activities (2) Areas (1) Regions (0) Abstract: A survey of diffuse CO2 efflux, soil temperature and soil-gas chemistry over areas of localized vegetation-kill on and around the resurgent dome of Long Valley caldera California was performed to evaluate the premise that gaseous and thermal anomalies are related to renewed intrusion of magma. Some kill sites are long-lived features and others have developed in the past few years. Total anomalous CO2 emissions from the
Ion Trap in a Semiconductor Chip
The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ion. Work on miniaturizing electromagnetic traps to the micrometer scale promises even higher levels of control and reliability. Compared with 'chip traps' for confining neutral atoms, ion traps with similar dimensions and power dissipation offer much higher confinement forces and allow unparalleled control at the single-atom level. Moreover, ion microtraps are of great interest in the development of miniature mass spectrometer arrays, compact atomic clocks, and most notably, large scale quantum information processors. Here we report the operation of a micrometer-scale ion trap, fabricated on a monolithic chip using semiconductor micro-electromechanical systems (MEMS) technology. We confine, laser cool, and measure heating of a single 111Cd+ ion in an integrated radiofrequency trap etched from a doped gallium arsenide (GaAs) heterostructure.
D. Stick; W. K. Hensinger; S. Olmschenk; M. J. Madsen; K. Schwab; C. Monroe
Parameter exploration of optically trapped liquid aerosols
When studying the motion of optically trapped particles on the $\\mu s$ time scale, in low viscous media such as air, inertia cannot be neglected. Resolution of unusual and interesting behaviour not seen in colloidal trapping experiments is possible. In attempt to explain the phenomena we use power spectral methods to perform a parameter study of the Brownian motion of optically trapped liquid aerosol droplets concentrated around the critically damped regime. We present evidence that the system is suitably described by a simple harmonic oscillator model which must include a description of Fax\\'{e}n's correction, but not necessarily frequency dependent hydrodynamic corrections to Stokes' law. We also provide results describing how the system behaves under several variables and discuss the difficulty in decoupling the parameters responsible for the observed behaviour. We show that due to the relatively low dynamic viscosity and high trap stiffness it is easy to transfer between over- and under-damped motion by experimentally altering either trap stiffness or damping. Our results suggest stable aerosol trapping may be achieved in under-damped conditions, but the onset of deleterious optical forces at high trapping powers prevents the probing of the upper stability limits due to Brownian motion.
D. R. Burnham; P. J. Reece; D. McGloin
Solar Cells, Wound Repair Winning GVC Technologies | ornl.gov
Solar Cells, Wound Repair Winning GVC Technologies Solar Cells, Wound Repair Winning GVC Technologies March 26, 2010 Graduate student teams from the University of Arkansas and the University of Maryland earned first place in the energy and security categories at the 2010 GVC hosted by ORNL March 24-26. The competition, in its fourth year, attracts students developing new technologies and venture investors with expertise in the market. The first-prize winners each received $25,000. Douglas Hutchings, Stephen Ritterbush, and Seth Shumate from Arkansas won first place in the energy division for Silicon Solar Solutions. "Our method replaces the expensive top layer of solar cells with a thinner, large-grain polysilicon at lower temperatures, which reduces cost and is appealing to manufacturers," said Ritterbush.
Controlling trapping and ejection of ions from multipole ...
Controlling trapping and ejection of ions from multipole guides and traps ... The concept can be used to control the kinetic energy of the
Sudex cover crops can kill and stunt subsequent tomato, ?lettuce and broccoli transplants through allelopathy
Article t Sudex cover crops can kill and stunt subsequentJ. Stapleton Grass cover crops can be harvested for biomassmay affect subsequent crops. We stud- ied the effects of
Summers, Charles G.; Mitchell, Jeffrey P.; Prather, Timothy S.; Stapleton, James J.
Well kill (quenching) study of thermal producers in the South Belridge field, California
This paper presents a field study confirming that damage occurs during kill (quenching) operations of thermal producers in the South Belridge field, Kern County, CA. Implementation of the recommendations from this study are expected to decrease damage that occurs during quenching by an average of 0.5 BOPD/kill. Results indicate that producers completed with openhole, gravel-packed, slotted liners in high-permeability sandstones can sustain substantial, irreversible damage when subjected to unfiltered produced-water kills. The damage results when previously produced sand and fines, which have settled in the flowline, are reinjected into the wellbore. Most of the damage is in the slots and gravel pack. Previous studies, field tests, and laboratory work quantifying the amount and site of the damage are detailed. Methods of determining water-quality specifications needed to minimize damage that occurs during well kills are outlined. The approach presented can be used to identify and quantify damage in any field where producers require kills before workover operations. The current recommended kill procedure is also included.
Fram, J.W.
FEMP-FTA--Steam Trap Performance Assessment
Steam Trap Function Steam Trap Function Steam traps are automatic valves used in every steam system to remove conden- sate, air, and other non-condensable gases while preventing or minimizing the passing of steam. If condensate is allowed to collect, it reduces the flow capacity of steam lines and the thermal capacity of heat transfer equipment. In addition, excess condensate can lead to "water hammer," with potentially destructive and dangerous results. Air that remains after system startup reduces steam pressure and temperature and may also reduce the thermal capacity of heat transfer equipment. Non-condensable gases, such as oxygen and carbon dioxide, cause corrosion. Steam that passes through the trap provides no heating ser- vice. This effectively reduces the heating capacity
Trapped Ions and Laser Cooling 11
... 2 GHz I ... monic well, eg, the absorption spectrum for the secular motion in an rf trap ... a sin- gle atom [mass of 100 u (atomic mass units)] starts from rest ...
Microfabrication techniques for trapped ion quantum ...
... used for micro-traps, starting with stacking multiple wafers to form a ... dc rf dc rf dc ... This section starts with a description of the tried and true gold-on ...
Laser cooling and trapping of neutral atoms*
... 1 m/s, any gas in equilibrium (other than spin-polarized atomic hydro- ... lattice-trapped atoms, a physical picture with the simplicity and power of the ...
Trapping of strangelets in the geomagnetic field
Strangelets coming from the interstellar medium (ISM) are an interesting target to experiments searching for evidence of this hypothetic state of hadronic matter. We entertain the possibility of a {\\it trapped} strangelet population, quite analogous to ordinary nuclei and electron belts. For a population of strangelets to be trapped by the geomagnetic field, these incoming particles would have to fulfill certain conditions, namely having magnetic rigidities above the geomagnetic cutoff and below a certain threshold for adiabatic motion to hold. We show in this work that, for fully ionized strangelets, there is a narrow window for stable trapping. An estimate of the stationary population is presented and the dominant loss mechanisms discussed. It is shown that the population would be substantially enhanced with respect to the ISM flux (up to two orders of magnitude) due to quasi-stable trapping.
L. Paulucci; J. E. Horvath; G. A. Medina-Tanco
Strangelets arriving from the interstellar medium are an interesting target for experiments searching for evidence of this hypothetical state of hadronic matter. We entertain the possibility of a trapped strangelet population, quite analogous to ordinary nuclei and electron belts. For a population of strangelets to be trapped by the geomagnetic field, these incoming particles would have to fulfill certain conditions, namely, having magnetic rigidities above the geomagnetic cutoff and below a certain threshold for adiabatic motion to hold. We show in this work that, for fully ionized strangelets, there is a narrow window for stable trapping. An estimate of the stationary population is presented and the dominant loss mechanisms discussed. It is shown that the population would be substantially enhanced with respect to the interstellar medium flux (up to 2 orders of magnitude) due to quasistable trapping.
Paulucci, L.; Horvath, J. E.; Medina-Tanco, G. A. [Instituto de Fisica-Universidade de Sao Paulo, Rua do Matao, Travessa R, 187, 05508-090, Cidade Universitaria, Sao Paulo SP (Brazil); Instituto de Astronomia, Geofisica e Ciencias Atmosfericas-Universidade de Sao Paulo, Rua do Matao, 1226, 05508-900, Cidade Universitaria, Sao Paulo SP (Brazil); Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico A.P. 70-543, C.U. Mexico D.F. (Mexico)
Paulucci, L; Medina-Tanco, G A
Shale gas is natural gas trapped inside
Shale gas is natural gas trapped inside formations of shale - fine grained sedimentary rocks that can be rich sources of petroleum and natural gas. Just a few years ago, much of...
Development of directional capabilities to an ultradeep water dynamic kill simulator and simulations runs
The world is dependent on the production of oil and gas, and every day the demand increases. Technologies have to keep up with the demand of this resource to keep the world running. Since hydrocarbons are finite and will eventually run out, the increasing demand of oil and gas is the impetus to search for oil in more difficult and challenging areas. One challenging area is offshore in ultradeep water, with water depths greater than 5000 ft. This is the new arena for drilling technology. Unfortunately with greater challenges there are greater risks of losing control and blowing out a well. A dynamic kill simulator was developed in late 2004 to model initial conditions of a blowout in ultradeep water and to calculate the minimum kill rate required to kill a blowing well using the dynamic kill method. The simulator was simple and efficient, but had limitations; only vertical wells could be simulated. To keep up with technology, modifications were made to the simulator to model directional wells. COMASim (Cherokee, Offshore Technology Research Center, Minerals Management Service, Texas A&M Simulator) is the name of the dynamic kill simulator. The new version, COMASim1.0, has the ability to model almost any type of wellbore geometry when provided the measured and vertical depths of the well. Eighteen models with varying wellbore geometry were simulated to examine the effects of wellbore geometry on the minimum kill rate requirement. The main observation was that lower kill rate requirement was needed in wells with larger measured depth. COMASim 1.0 cannot determine whether the inputs provided by the user are practical; COMASim 1.0 can only determine if the inputs are incorrect, inconsistent or cannot be computed. If unreasonable drilling scenarios are input, unreasonable outputs will result. COMASim1.0 adds greater functionality to the previous version while maintaining the original framework and simplicity of calculations and usage.
Meier, Hector Ulysses
Trapping and dark current in plasma-based accelerators
The trapping of thermal electrons in a nonlinear plasma wave of arbitrary phase velocity is investigated. The threshold plasma wave amplitude for trapping plasma electrons is calculated, thereby determining the fraction trapped and the expected dark current in a plasma-based accelerator. It is shown that the presence of a laser field (e.g., trapping in the self-modulated regime of the laser wakefield accelerator) increases the trapping threshold. Implications for experimental and numerical laser-plasma studies are discussed.
Schroder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.
Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation
Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled DC electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on DC electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains.
S. Charles Doret; Jason M. Amini; Kenneth Wright; Curtis Volin; Tyler Killian; Arkadas Ozakin; Douglas Denison; Harley Hayden; C. -S. Pai; Richart E. Slusher; Alexa W. Harter
Modular cryostat for ion trapping with surface-electrode ion traps
We present a simple cryostat purpose built for use with surface-electrode ion traps, designed around an affordable, large cooling power commercial pulse tube refrigerator. A modular vacuum enclosure with a single vacuum space facilitates interior access, and enables rapid turnaround and flexiblity for future modifications. Long rectangular windows provide nearly 360 degrees of optical access in the plane of the ion trap, while a circular bottom window near the trap enables NA 0.4 light collection without the need for in-vacuum optics. We evaluate the system's mechanical and thermal characteristics, and we quantify ion trapping performance by trapping 40Ca+, finding small stray electric fields, long ion lifetimes, and low ion heating rates.
Grahame Vittorini; Kenneth Wright; Kenneth R. Brown; Alexa W. Harter; S. Charles Doret
Charge trapping in imidazolium ionic liquids
trapping in imidazolium ionic liquids trapping in imidazolium ionic liquids I. A. Shkrob and J. F. Wishart J. Phys. Chem. B 113, 5582-5592 (2009). [Find paper at ACS Publications] or use ACS Articles on Request Abstract: Room-temperature ionic liquids (ILs) are a promising class of solvents for applications ranging from photovoltaics to solvent extractions. Some of these applications involve the exposure of the ILs to ionizing radiation, which stimulates interest in their radiation and photo- chemistry. In the case of ILs consisting of 1,3-dialkylimidazolium cations and hydrophobic anions, ionization, charge transfer and redox reactions yield charge-trapped species thought to be radicals resulting from neutralization of the constituent ions. Using computational chemistry methods and the recent results on electron spin resonance (ESR) and transient absorption
Energy Savings Through Steam Trap Management
Sustainability and energy management are broad topics which have become a common focus in industry. Recognizing the need for greater cost reduction and competitive advantage through sustainability, industry is putting forth resources to improve energy management controls. When the topic of energy management relates to steam trap management however, the focus becomes less clear and action less notable. The seemingly �low hanging� fruit of steam traps are not often tied to significant and sustainable energy management projects. Typically this holds true because of the failure of industry to put a value on the cost of steam and because of the lack of energy tracking from failed steam traps as part of best practice. The use of technology can help industry transform how steam systems are managed and sustainability in steam systems is achieved.
Gibbs, C.
The Kill-a-Watt Competition at University of Central Florida | Department
The Kill-a-Watt Competition at University of Central Florida The Kill-a-Watt Competition at University of Central Florida The Kill-a-Watt Competition at University of Central Florida Addthis Description At the University of Central Florida, students have taken it upon themselves to create a culture of energy efficiency. Each year, different dorm buildings compete to see who can save the most. In 2009, the school saw a total savings of $27,000. As of March 2010, they've saved over $24,000 this year alone. Speakers Chris Castro, Alexandra Kennedy, Margaret Lo, David Norvell, Keith Coelho, John Hitt PhD Duration 5:40 Topic Energy Efficiency Commercial Heating & Cooling Consumption Credit Energy Department Video CHRIS CASTRO: Last summer, I was an intern at the Department of Energy Office of Energy Efficiency and Renewable Energy and I got a chance to
Thermal electric vapor trap arrangement and method
A technique for trapping vapor within a section of a tube is disclosed herein. This technique utilizes a conventional, readily providable thermal electric device having a hot side and a cold side and means for powering the device to accomplish this. The cold side of this device is positioned sufficiently close to a predetermined section of the tube and is made sufficiently cold so that any condensable vapor passing through the predetermined tube section is condensed and trapped, preferably within the predetermined tube section itself.
Alger, Terry (Tracy, CA)
Parametric Resonance of Optically Trapped Aerosols
The Brownian dynamics of an optically trapped water droplet are investigated across the transition from over to under-damped oscillations. The spectrum of position fluctuations evolves from a Lorentzian shape typical of over-damped systems (beads in liquid solvents), to a damped harmonic oscillator spectrum showing a resonance peak. In this later under-damped regime, we excite parametric resonance by periodically modulating the trapping power at twice the resonant frequency. The power spectra of position fluctuations are in excellent agreement with the obtained analytical solutions of a parametrically modulated Langevin equation.
R. Di Leonardo; G. Ruocco; J. Leach; M. J. Padgett; A. J. Wright; J. M. Girkin; D. R. Burnham; D. McGloin
The effect of Stromal cell Derived Factor-1 (SDF-1) and collagen-GAG (Glycosaminoglycan) scaffold on skin wound healing
Wound healing is an intricate biological process requiring the appropriate balance of matrix and growth factors. Apart from causing physical deformity, adult wound healing results in the formation of scar tissue, which can ...
Sarkar, Aparajita
The Engineered Approach to Energy and Maintenance Effective Steam Trapping
The engineered approach to steam trap sizing, selection and application has proven effective in significantly reducing a plant's fuel consumption, maintenance and trap replacement costs while improving thermal efficiency and overall steam system performance. New field test procedures for measuring condensate load and steam loss have proven valuable in sizing traps and to determine which trap is the most energy efficient. The combination of using the engineered approach to steam trapping, field tests to verify trap performance and good maintenance practices has contributed to a major reduction in energy consumption of 10-50% in many industrial plants.
Krueger, R. G.; Wilt, G. W.
Marginally trapped surfaces in spaces of oriented geodesics
We investigate the geometric properties of marginally trapped surfaces (surfaces which have null mean curvature vector) in the spaces of oriented geodesics of Euclidean 3-space and hyperbolic 3-space, endowed with their canonical neutral Kaehler structures. We prove that every rank one surface in these four manifolds is marginally trapped. In the Euclidean case we show that Lagrangian rotationally symmetric sections are marginally trapped and construct an explicit family of marginally trapped Lagrangian tori. In the hyperbolic case we explore the relationship between marginally trapped and Weingarten surfaces, and construct examples of marginally trapped surfaces with various properties.
Brendan Guilfoyle; Nikos Georgiou
The Spindown of Bottom-Trapped Plumes
This note considers the decay of a bottom-trapped freshwater plume after the causative freshwater inflow has ceased. It is shown that shortly after the low-density inflow stops, the barotropic pressure field that it created radiates away and the ...
Ricardo P. Matano; Elbio D. Palma
The stability of Killing-Cauchy horizons in colliding plane wave space-times
It is confirmed rigorously that the Killing-Cauchy horizons, which sometimes occur in space-times representing the collision and subsequent interaction of plane gravitational waves in a Minkowski background, are unstable with respect to bounded perturbations of the initial waves, at least for the case in which the initial waves have constant aligned polarizations.
J. B. Griffiths
Uniformly wound superconducting coil and method of making same
A coil of superconducting wire for a superconducting magnet having a relaely dense and uniformly spaced winding to enhance the homogeneity and strength of the magnetic field surrounding the coil and a method of winding the same wherein the mandrel used to wind said coil comprises removable spacers and retainers forming a plurality of outwardly opening slots, each of said slots extending generally about the periphery of the mandrel and being sized to receive and outwardly align and retain successive turns of the superconducting wire within each slot as the wire is wound around and laterally across the mandrel to form a plurality of wire ribbons of a predetermined thickness laterally across the mandrel.
Mookerjee, Sumit (Cedar Hill, TX); Weijun, Shen (Beijun, CN); Yager, Billy (Waxahachie, TX)
A coil of superconducting wire for a superconducting magnet is described having a relatively dense and uniformly spaced winding to enhance the homogeneity and strength of the magnetic field surrounding the coil and a method of winding the same wherein the mandrel used to wind said coil comprises removable spacers and retainers forming a plurality of outwardly opening slots, each of said slots extending generally about the periphery of the mandrel and being sized to receive and outwardly align and retain successive turns of the superconducting wire within each slot as the wire is wound around and laterally across the mandrel to form a plurality of wire ribbons of a predetermined thickness laterally across the mandrel. 8 figures.
Mookerjee, S.; Weijun, S.; Yager, B.
Towards a cryogenic planar ion trap for Sr-88
This thesis describes experiments with ion traps constructed with electrodes in a single two-dimensional plane, and ion traps operated in a cryogenic environment at 77K and 4K temperatures. These two technologies address ...
Bakr, Waseem (Waseem S.)
Two-dimensional ion trap lattice on a microchip
Microfabricated ion traps are a major advancement towards scalable quantum computing with trapped ions. The development of more flexible ion trap designs, in which tailored arrays of ions are positioned in two dimensions above a microfabricated surface, would lead to applications in fields as varied as quantum simulation, metrology and atom-ion interactions. Current surface ion traps often have low trap depths and high heating rates, due to the size of the voltages that can be applied to them, limiting the fidelity of quantum gates. In this article we report on a fabrication process that allows for the application of very high voltages to microfabricated devices in general and we apply this advance to fabricate a 2D ion trap lattice on a microchip. Our scalable microfabricated architecture allows for reliable trapping of 2D ion lattices, long ion lifetimes due to the deep trapping potential, rudimentary shuttling between lattice sites and the ability to deterministically introduce defects into the ion lattice.
R. C. Sterling; H. Rattanasonti; S. Weidt; K. Lake; P. Srinivasan; S. C. Webster; M. Kraft; W. K. Hensinger
Ideal Multipole Ion Traps from Planar Ring Electrodes
We present designs for multipole ion traps based on a set of planar, annular, concentric electrodes which require only rf potentials to confine ions. We illustrate the desirable properties of the traps by considering a few simple cases of confined ions. We predict that mm-scale surface traps may have trap depths as high as tens of electron volts, or micromotion amplitudes in a 2-D ion crystal as low as tens of nanometers, when parameters of a magnitude common in the field are chosen. Several example traps are studied, and the scaling of those properties with voltage, frequency, and trap scale, for small numbers of ions, is derived. In addition, ions with very high charge-to-mass ratios may be confined in the trap, and species of very different charge-to-mass ratios may be simultaneously confined. Applications of these traps include quantum information science, frequency metrology, and cold ion-atom collisions.
Robert J. Clark
Transport of Trapped-Ion Qubits within a Scalable Quantum ...
... 158 6.13 Glass vacuum envelope. . . . . ... 159 6.14 Picture of the trap inside of the glass envelope. . . . . ...
High voltage gas insulated transmission line with continuous particle trapping
This invention provides a novel high voltage gas insulated transmission line utilizing insulating supports spaced at intervals with snap-in means for supporting a continuous trapping apparatus and said trapping apparatus having perforations and cutouts to facilitate trapping of contaminating particles and system flexibility.
Cookson, Alan H. (Pittsburgh, PA); Dale, Steinar J. (Monroeville, PA)
Use of Bullet Traps and Steel Targets
USE OF BULLET TRAPS AND USE OF BULLET TRAPS AND STEEL TARGETS U.S. DEPARTMENT OF ENERGY Office of Health, Safety and Security AVAILABLE ONLINE AT: INITIATED BY: http://www.hss.energy.gov Office of Health, Safety and Security Notices This document is intended for the exclusive use of elements of the Department of Energy (DOE), to include the National Nuclear Security Administration, their contractors, and other government agencies/individuals authorized to use DOE facilities. DOE disclaims any and all liability for personal injury or property damage due to use of this document in any context by any organization, group, or individual, other than during official government activities. Local DOE management is responsible for the proper execution of firearms-related programs for
Noise-enhanced trapping in chaotic scattering
We show that noise enhances the trapping of trajectories in scattering systems. In fully chaotic systems, the decay rate can decrease with increasing noise due to a generic mismatch between the noiseless escape rate and the value predicted by the Liouville measure of the exit set. In Hamiltonian systems with mixed phase space we show that noise leads to a slower algebraic decay due to trajectories performing a random walk inside Kolmogorov-Arnold-Moser islands. We argue that these noise-enhanced trapping mechanisms exist in most scattering systems and are likely to be dominant for small noise intensities, which is confirmed through a detailed investigation in the Henon map. Our results can be tested in fluid experiments, affect the fractal Weyl's law of quantum systems, and modify the estimations of chemical reaction rates based on phase-space transition state theory.
Altmann, Eduardo G; 10.1103/PhysRevLett.105.244102
A quantum information processor with trapped ions
Quantum computers hold the promise to solve certain problems exponentially faster than their classical counterparts. Trapped atomic ions are among the physical systems in which building such a computing device seems viable. In this work we present a small-scale quantum information processor based on a string of $^{40}$Ca${^+}$ ions confined in a macroscopic linear Paul trap. We review our set of operations which includes non-coherent operations allowing us to realize arbitrary Markovian processes. In order to build a larger quantum information processor it is mandatory to reduce the error rate of the available operations which is only possible if the physics of the noise processes is well understood. We identify the dominant noise sources in our system and discuss their effects on different algorithms. Finally we demonstrate how our entire set of operations can be used to facilitate the implementation of algorithms by examples of the quantum Fourier transform and the quantum order finding algorithm.
Philipp Schindler; Daniel Nigg; Thomas Monz; Julio T. Barreiro; Esteban Martinez; Shannon X. Wang; Stephan Quint; Matthias F. Brandl; Volckmar Nebendahl; Christian F. Roos; Michael Chwalla; Markus Hennrich; Rainer Blatt
Iterated dynamical maps in an ion trap
Iterated dynamical maps offer an ideal setting to investigate quantum dynamical bifurcations and are well adapted to few-qubit quantum computer realisations. We show that a single trapped ion, subject to periodic impulsive forces, exhibits a rich structure of dynamical bifurcations derived from the Jahn-Teller Hamiltonian flow model. We show that the entanglement between the oscillator and electronic degrees of freedom reflects the underlying dynamical bifurcation in a Floquet eigenstate.
M. Duncan; J. Links; G. J. Milburn
Effect of trapping in degenerate quantum plasmas
In the present work we consider the effect of trapping as a microscopic process in a plasma consisting of quantum electrons and nondegenerate ions. The formation of solitary structures is investigated in two cases: first when the electrons are fully degenerate and second when small temperature effects are taken into account. It is seen that not only rarefactive but coupled rarefactive and compressive solitons are obtained under different temperature conditions.
Shah, H. A.; Qureshi, M. N. S. [Department of Physics, GC University, Lahore 54000 (Pakistan); Tsintsadze, N. [Department of Physics, GC University, Lahore 54000 (Pakistan); Salam Chair, GC University, Lahore 54000 (Pakistan)
Demonstration of a scalable, multiplexed ion trap for quantum information processing
A scalable, multiplexed ion trap for quantum information processing is fabricated and tested. The trap design and fabrication process are optimized for scalability to small trap size and large numbers of interconnected traps, and for integration of control ...
D. R. Leibrandt; J. Labaziewicz; R. J. Clark; I. L. Chuang; R. J. Epstein; C. Ospelkaus; J. H. Wesenberg; J. J. Bollinger; D. Leibfried; D. J. Wineland; D. Stick; J. Sterk; C. Monroe; C.-S. Pai; Y. Low; R. Frahm; R. E. Slusher
What To Do With Cold Traps and Why
Increased emphasis on energy management has helped sites reduce system cost through the diagnosis and repair of �Leaking� or �Blowing� steam traps (�Leakage Failures�). Timely maintenance response is a significant action to lower energy use and GHG emissions generated by steam production. But, what action should be taken with Cold Traps? In every steam trap survey to determine the steam trap population�s current state of health, there are usually a significant amount of steam traps determined to be �Cold� or �Low Temp� (�Drainage Failures� or �Cold Traps�). It seems that site personnel commonly assign a lower response priority to these Drainage Failures traps, and sometimes actually implement a practice to intentionally convert Leaking traps into Cold Traps by closing the inlet stop valve to immediately stop energy leakage. Subsequently, they may label those traps as �Valved- Out� or �Out of Service,� but those trap stations were originally designed as needed to drain retained condensate from the system. So, the correct designation for such a trap station is �Cold,� regardless of the current intention. If the trap station does not drain condensate and is not hot, it is �Cold.� It can be astounding that many sites are not convinced of what actions or priority to take to repair Cold Traps, even while intrinsically understanding that there is something wrong with having Cold Traps that cannot drain condensate from a steam system. It often is simply because sites may not be fully aware of the potential dangers of uncorrected Cold Traps or the significant safety, reliability, and energy benefits of addressing them. Although safety is always the main priority, it cannot be overstated that there are huge reliability and energy benefits to prioritized repair of Cold Traps. Unfortunately, proactive response to repair Cold Traps in a steam system is not always achieved, often because the real benefits of such a response are not understood. Therefore, further review of �WHAT TO DO ABOUT COLD TRAPS�AND WHY?� is warranted for safe, reliable, and energy-efficient management of the condensate discharge locations (CDLs). Several tables are provided to help sites valuate the cost impact of Cold Traps in their steam systems by using readily available historical data.
Risko, J. R.; Walter, J. P.
Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap
Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antiproton and antihydrogen trajectories in this magnetic geometry, and reconstruct the antihydrogen energy distribution from the measured annihilation time history.
C. Amole; G. B. Andresen; M. D. Ashkezari; M. Baquero-Ruiz; W. Bertsche; E. Butler; C. L. Cesar; S. Chapman; M. Charlton; A. Deller; S. Eriksson; J. Fajans; T. Friesen; M. C. Fujiwara; D. R. Gill; A. Gutierrez; J. S. Hangst; W. N. Hardy; M. E. Hayden; A. J. Humphries; R. Hydomako; L. Kurchaninov; S. Jonsell; N. Madsen; S. Menary; P. Nolan; K. Olchanski; A. Olin; A. Povilus; P. Pusa; F. Robicheaux; E. Sarid; D. M. Silveira; C. So; J. W. Storey; R. I. Thompson; D. P. van der Werf; J. S. Wurtele
Steam Traps-The Oft Forgotten Energy Conservation Treasure
In these days of high technology, the steam trap is often treated as a commodity item, forgotten by many and respected by a relative few. Yet, in many facilities, widespread undetected failure of steam traps has wasted 5-15% of a plant's total steam generation. Stopping this waste represents a major energy conservation treasure characterized by low investment and a fast payback. The proper application of steam trap technology requires the experience and judgment of a dedicated champion at each location. This paper will present an overview of a working steam trap program starting with the initial survey and loss estimates. Trap characteristics and performance by generic type will be discussed with practical examples utilized to illustrate the myths in steam trap sizing and the consequences of over-sizing. Standardization of trap inventory, training and follow-up are the other key program elements addressed.
Pychewicz, F. S.
A wound-induced Wnt expression program controls planarian regeneration polarity
Regeneration requires specification of the identity of new tissues to be made. Whether this process relies only on intrinsic regulative properties of regenerating tissues or whether wound signaling provides input into ...
Petersen, Christian P.
Transcriptional analysis of the healing response of wounded nerves treated with collagen and silicone tubes
This study examines the transcriptional differences between nerve wounds treated with silicone tubes and those treated with collagen nerve regeneration templates. The primary motivation for the study is to test the hypothesis ...
Wong, Matthew Q
Tension, Free Space, and Cell Damage in a Microfluidic Wound Healing Assay
We use a novel, microfluidics-based technique to deconstruct the classical wound healing scratch assay, decoupling the contribution of free space and cell damage on the migratory dynamics of an epithelial sheet. This method ...
Murrell, Michael
Control system for a wound-rotor motor
A load switching circuit for switching two or more transformer taps under load carrying conditions includes first and second parallel connected bridge rectifier circuits which control the selective connection of a direct current load to taps of a transformer. The first bridge circuit is normally conducting so that the load is connected to a first tap through the first bridge circuit. To transfer the load to the second tap, a switch is operable to connect the second bridge circuit to a second tap, and when the second bridge circuit begins to conduct, the first bridge circuit ceases conduction because the potential at the second tap is higher than the potential at the first tap, and the load is thus connected to the second tap through the second bridge circuit. The load switching circuit is applicable in a motor speed controller for a wound-rotor motor for effecting tap switching as a function of motor speed while providing a stepless motor speed control characteristics.
Ellis, J.N.
A load switching circuit for switching two or more transformer taps under load carrying conditions includes first and second parallel connected bridge rectifier circuits which control the selective connection of a direct current load to taps of a transformer. The first bridge circuit is normally conducting so that the load is connected to a first tap through the first bridge circuit. To transfer the load to the second tap, a switch is operable to connect the second bridge circuit to a second tap, and when the second bridge circuit begins to conduct, the first bridge circuit ceases conduction because the potential at the second tap is higher than the potential at the first tap, and the load is thus connected to the second tap through the second bridge circuit. The load switching circuit is applicable in a motor speed controller for a wound-rotor motor for effecting tap switching as a function of motor speed while providing a stepless motor speed control characteristic.
Ellis, James N. (Chatsworth, CA)
Void trapping of hydrogen in sintered iron
The effect of void trapping of hydrogen in iron was studied using the gas-phase permeation technique. Iron membranes of controlled void density, varying from 92% to 98% were prepared by press and sintering of electrolytic iron powder. The presence of internal voids showed no effect on the steady state flux of hydrogen through the membrane. The effective diffusivity, obtained by the time lag method, increased with the increase of input hydrogen partial pressure. This disagreement with the prediction of the theory in literature was explained by the existence of hydrogen in both the diatomic gaseous form and as adsorbed hydrogen. This explanation was further confirmed by examining the dependence of trapped hydrogen concentration with pressure. The linear dependence of trapped hydrogen concentration in voids with external hydrogen partial pressure for samples of 96%, 94% and 92% dense were given respectively by C/sub g/ = (1.5 +- 0.2) x 10/sup 15/ P + (3.2 +- 0.5) x 10/sup 14/ atoms of H/c.c. C/sub g/ = (2.1 +- 0.6) x 10/sup 15/ P + (1.7 +- 0.5) x 10/sup 15/ atoms of H/c.c. C/sub g/ = (4.5 +- 0.3) x 10/sup 15/ P + (6.5 +- 0.2) x 10/sup 15/ atoms of H/c.c. The discrepancy between the reported values and the values predicted by theory was explained by the poisoning of some of the voids by surface oxides.
Wong, K.C.
Universal digital quantum simulation with trapped ions
A digital quantum simulator is an envisioned quantum device that can be pro- grammed to efficiently simulate any other local system. We demonstrate and investigate the digital approach to quantum simulation in a system of trapped ions. Using sequences of up to 100 gates and 6 qubits, the full time dynamics of a range of spin systems are digitally simulated. Interactions beyond those naturally present in our simulator are accurately reproduced and quantitative bounds are provided for the overall simulation quality. Our results demon- strate the key principles of digital quantum simulation and provide evidence that the level of control required for a full-scale device is within reach.
B. P. Lanyon; C. Hempel; D. Nigg; M. M�ller; R. Gerritsma; F. Z�hringer; P. Schindler; J. T. Barreiro; M. Rambach; G. Kirchmair; M. Hennrich; P. Zoller; R. Blatt; C. F. Roos
Gas turbine engines with particle traps
A gas turbine engine (10) incorporates a particle trap (46) that forms an entrapment region (73) in a plenum (24) which extends from within the combustor (18) to the inlet (32) of a radial-inflow turbine (52, 54). The engine (10) is thereby adapted to entrap particles that originate downstream from the compressor (14) and are otherwise propelled by combustion gas (22) into the turbine (52, 54). Carbonaceous particles that are dislodged from the inner wall (50) of the combustor (18) are incinerated within the entrapment region (73) during operation of the engine (10).
Boyd, Gary L. (Tempe, AZ); Sumner, D. Warren (Phoenix, AZ); Sheoran, Yogendra (Scottsdale, AZ); Judd, Z. Daniel (Phoenix, AZ)
Impurity beam-trapping instability in tokamaks
The sensitivity of neutron energy production to the impurity trapping of injected neutral beams is considered. This process is affected by inherent low-Z contamination of the tritium pre-heat plasma, by the species composition of the neutral beam, and by the entrance angle of the beam. The sensitivities of the process to these variables, and to the variation of wall material are compared. One finds that successful use of a low-Z, low-sputtering material can appreciably lengthen the useful pulse length. (auth)
Hogan, J.T.; Howe, H.C.
Trapped Quintessential Inflation from Flux Compactifications
Quintessential inflation is studied using a string modulus as the inflaton - quintessence field. It is assumed that the modulus crosses an enhanced symmetry point (ESP) in field space. Particle production at the ESP temporarily traps the modulus resulting in a period of inflation. After reheating, the modulus freezes due to cosmological friction at a large value, such that its scalar potential is dominated by contributions due to fluxes in the extra dimensions. The modulus remains frozen until the present, when it can become quintessence.
Konstantinos Dimopoulos
Construction and Operational Experience with a Superconducting Octupole Used to Trap Antihydrogen
A superconducting octupole magnet has seen extensive service as part of the ALPHA experiment at CERN. ALPHA has trapped antihydrogen, a crucial step towards performing precision measurements of anti-atoms. The octupole was made at the Direct Wind facility by the Superconducting Magnet Division at Brookhaven National Laboratory. The magnet was wound with a six-around-one NbTi cable about 1 mm in diameter. It is about 300 mm long, with a radius of 25 mm and a peak field at the conductor of 4.04 T. Specific features of the magnet, including a minimal amount of material in the coil and coil ends with low multipole content, were advantageous to its use in ALPHA. The magnet was operated for six months a year for five years. During this time it underwent about 900 thermal cycles (between 4K and 100K). A novel operational feature is that during the course of data-taking the magnet was repeatedly shut off from its 950 A operating current. The magnet quenches during the shutoff, with a decay constant of 9 ms. Over the course of the five years, the magnet was deliberately quenched many thousands of times. It still performs well.
Wanderer P.; Escallier, J.; Marone, A.; Parker, B.
Lysosomal Trafficking, Antigen Presentation, and Microbial Killing Are Controlled by the Arf-like GTPase Arl8b
Antigen presentation and microbial killing are critical arms of host defense that depend upon cargo trafficking into lysosomes. Yet, the molecular regulators of traffic into lysosomes are only partly understood. Here, using ...
Garg, Salil
Seasonal Prediction of Killing-Frost Frequency in South-Central Canada during the Cool/Overwintering-Crop Growing Season
Seasonal killing-frost frequency (KFF) during the cool/overwintering-crop growing season is important for the Canadian agricultural sector to prepare and respond to such extreme agrometeorological events. On the basis of observed daily surface air ...
Zhiwei Wu; Hai Lin; Yun Li; Youmin Tang
New nano trap protects environment | Argonne National Laboratory
New nano trap protects environment New nano trap protects environment By Tona Kunz * October 31, 2012 Tweet EmailPrint This story was originally published in volume 10, number 5 of Innovation magazine. A new type of nanoscale molecular trap makes it possible for industry to store large amounts of hydrogen in small fuel cells or capture, compact and remove volatile radioactive gas from spent nuclear fuel in an affordable, easily commercialized way. The ability to adjust the size of the trap openings to select for specific molecules or to alter how molecules are released at industrially accessible pressures makes the trap uniquely versatile. The trap is constructed of commercially available material and made possible through collaborative work at Argonne and Sandia national laboratories. "This introduces a new class of materials to nuclear waste remediation,"
Energy trapping from Hagedorn densities of states
In this note, we construct simple stochastic toy models for holographic gauge theories in which distributions of energy on a collection of sites evolve by a master equation with some specified transition rates. We build in only energy conservation, locality, and the standard thermodynamic requirement that all states with a given energy are equally likely in equilibrium. In these models, we investigate the qualitative behavior of the dynamics of the energy distributions for different choices of the density of states for the individual sites. For typical field theory densities of states (\\log(\\rho(E)) ~ E^{\\alphaenergy spread out relatively quickly. For large N gauge theories with gravitational duals, the density of states for a finite volume of field theory degrees of freedom typically includes a Hagedorn regime (\\log(\\rho(E)) ~ E). We find that this gives rise to a trapping of energy in subsets of degrees of freedom for parametrically long time scales before the energy leaks away. We speculate that this Hagedorn trapping may be part of a holographic explanation for long-lived gravitational bound states (black holes) in gravitational theories.
Connor Behan; Klaus Larjo; Nima Lashkari; Brian Swingle; Mark Van Raamsdonk
Volatiles trapped in coals: Second quarterly report
We have been able to collect and characterize volatiles that are evolved in the grinding of coal. We have developed a very sensitive method for collecting volatiles evolved in grinding. A sealed, gas tight, grinding apparatus has been built. With this system we can collect volatiles freed from the coal matrix during grinding. To do this a 125 cm/sup 3/ sample of coal is placed in to a 1 liter sealable ball mill jar. The jar is evacuated and the coal ground for 1 hr. The jar is then removed from the ball mill and evacuated into our sample collection system. Gas from the jar is pumped through two stages of dust filtering into a liquid nitrogen cold trap charged with 5 ml of methylene chloride. After warming the trap is shaken so that any gas from the sample mixes with and dissolves in the methylene chloride. One microliter samples of the methylene chloride are injected into a Finnegan GCMS. Preliminary analysis of mass spectra from peaks in the RIC show the presence of hydrocarbons. It was possible to definitively identify cyclohexene. The total amount of hydrocarbons seen is low. The attached figure is the mass spectra of the cyclohexene that was collected from the ground coal. 1 fig.
Sutter, J.R.; Halpern, J.B.
Lymph node clearance of plutonium from subcutaneous wounds in beagles
The lymph node clearance of /sup 239/Pu O/sub 2/ administered as insoluble particles from subcutaneous implants was studied in adult beagles to simulate accidental contamination of hand wounds. External scintillation data were collected from the popliteal lymph nodes of each dog after 9.2 to 39.4 mu Ci of plutonium oxide was subcutaneously implanted into the left or right hind paws. The left hind paw was armputated 4 weeks after implantation to prevent continued deposition of plutonium oxide particles in the left popliteal lymph node. Groups of 3 dogs were sacrificed 4, 8, 16, and 32 weeks after plutonium implantation for histopathologic, electron microscopic, and radiochemical analysis of regional lymph nodes. An additional group of dogs received treatment with the chelating agent diethyenetriaminepentaacetic acid (DTPA). Plutonium rapidly accumulated in the popliteal lymph nodes after subcutaneous injection into the hind paw, and 1 to 10% of the implant dose was present in the popliteal lymph nodes at the time of necropsy. Histopathologic changes in the popliteal lymph nodes with plutonium particles were characterized primarily by reticular cell hyperplasia, increased numbers of macrophages, necrosis, and fibroplasia. Eventually, the plutonium particles became sequestered by scar tissue that often replaced the entire architecture of the lymph node. Light microscopic autoradiographs of the popliteal lymph nodes showed a time-related increase in number of alpha tracks per plutonium source. Electron microscopy showed that the plutonium particles were aggregated in phagolysosomes of macrophages. There was slight clearance of plutonium from the popliteal lymph nodes of dogs monitored for 32 weeks. The clearance of plutonium particles from the popliteal lymph nodes was associated with necrosis of macrophages. The external iliac lymph nodes contained fewer plutonium particles than the popliteal lymph nodes and histopathologic changes were less severe. The superficial inguinal lymph nodes of one dog contained appreciable amounts of plutonium. Treatment with diethylenetriaminepentaacetic acid (DTPA) did not have a measurable effect on the clearance of plutonium from the popliteal lymph nodes. (60 references) (auth)
Dagle, G.E.
Gas insulated transmission line having tapered particle trapping ring
A gas-insulated transmission line includes an outer sheath, an inner conductor, insulating supports and an insulating gas. A particle-trapping ring is secured to each insulating support, and it is comprised of a central portion and two tapered end portions. The ends of the particle trapping ring have a smaller diameter than the central portion of the ring, so as to enable the use of the particle trapping ring in a curved transmission line.
Cookson, Alan H. (Pittsburgh, PA)
Trap-depth determination from residual gas collisions
We present a method for determining the depth of an atomic or molecular trap of any type. This method relies on a measurement of the trap loss rate induced by collisions with background gas particles. Given a fixed gas composition, the loss rate uniquely determines the trap depth. Because of the ''soft'' long-range nature of the van der Waals interaction, these collisions transfer kinetic energy to trapped particles across a broad range of energy scales, from room temperature to the microkelvin energy scale. The resulting loss rate therefore exhibits a significant variation over an enormous range of trap depths, making this technique a powerful diagnostic with a large dynamic range. We present trap depth measurements of a Rb magneto-optical trap using this method and a different technique that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state. The main advantage of the method presented here is its large dynamic range and applicability to traps of any type requiring only knowledge of the background gas density and the interaction potential between the trapped and background gas particles.
Van Dongen, J.; Zhu, C.; Clement, D.; Dufour, G.; Madison, K. W. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, V6T 1Z1 (Canada); Booth, J. L. [Physics Department, British Columbia Institute of Technology, 3700 Willingdon Avenue, Burnaby, British Columbia, V5G 3H2 (Canada)
Bon MOT: Innovative Atom Trap Catches Highly Magnetic ...
... of a cloud of erbium atoms trapped and cooled and a ... all the while extracting energy and cooling them ... only a single laser and can cool erbium atoms ...
Possible mechanism for enhancing the trapping and cooling of antihydrogen
We propose a usage of microwave radiation in a magnetic trap for improving the cooling and trapping of cold antihydrogen atoms which are initially produced in high magnetic moment states. Inducing transitions toward lower magnetic moments near the turning points of the atom in the trap, followed by spontaneous emission, should enhance the number of trappable atoms. We present results of simulations based on a typical experimental condition of the antihydrogen experiments at CERN. This technique should also be applicable to other trapped high magnetic moment Rydberg atoms.
Cesar, C. L.; Zagury, N. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ (Brazil); Robicheaux, F. [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)
Controlled Kinetic Energy Ion Source for Miniature Ion Trap ...
with electronic signal sources coupled to the electrodes. The ion trap can be machined with conventional materials and methods and has demonstrated
Onset of Fermi Degeneracy in a Trapped Atomic Gas
... in the total energy of the ultra- cold, trapped ... of charge e onto a cryogenic capacitor C, and ... standards are known as �calculable capacitors� and rely ...
NIST Racetrack Ion Trap is a Contender in Quantum ...
... ion trap under development as possible hardware for a future quantum computer. ... loading of 10 magnesium ions at once and transport of an ion ...
Trapping and Measuring Charged Particles in Liquids - Energy ...
Genome sequencing especially benefits from the nanoscale approach. Description. The trap is a three-layer, three-dimensional crossing metal/insulator ...
How Algae Use a "Sulfate Trap" to Selectively Biomineralize Strontium...
| 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed How Algae Use a "Sulfate Trap" to Selectively Biomineralize Strontium OCTOBER 20, 2011 Bookmark...
Bait formulations and longevity of navel orangeworm egg traps tested
there were 1% or 3% crude almond oil received more eggshaving no letters crude almond oil or traps baited with inone standard error. crude almond oil received significantly
Kuenen, L.P.S. Bas; Bentley, Walt; Rowe, Heather; Ribeiro, Brian
`Trapped' Ions Provide First View of Light Property
... PHYSICS `Trapped' Ions Provide First View of Light Property. ... Quantum theory states that light can act either as a wave or as a particle. ...
November 18, 2010: Antimatter Trapped and Stored | Department...
and Stored November 18, 2010 The Department's Lawrence Berkeley National Laboratory (LBNL) announces that atoms of antimatter have been trapped and stored for the first time in...
traps tested by L.P.S. (Bas) Kuenen, Walt Bentley, Heatherfor at least 10 weeks. L.P.S. (Bas) Kuenen is Research
Josephson oscillations between exciton condensates in electrostatic traps
Technological advances allow for tunable lateral confinement of cold dipolar excitons in coupled quantum wells. We consider theoretically the Josephson effect between exciton condensates in two traps separated by a weak link. The flow of the exciton supercurrent is driven by the dipole-energy difference between the traps. The Josephson oscillations may be observed after ensemble average of the time correlation of photons separately emitted from the two traps. The fringe visibility is controlled by the trap coupling and is robust against quantum and thermal fluctuations.
Rontani, Massimo [CNR-INFM Research Center on nanoStructures and bioSystems at Surfaces (S3), Via Campi 213/A, 41125 Modena (Italy); Sham, L. J. [Department of Physics, University of California San Diego, La Jolla, California 92093-0319 (United States)
Tellurium Inclusions and Carrier Trapping Times in Detector Grade ...
Spatial mapping of carrier trapping times and defect densities in CZT was performed to determine the relationship between defect density and electronic decay.
The angular momentum of a magnetically trapped atomic condensate
For an atomic condensate in an axially symmetric magnetic trap, the sum of the axial components of the orbital angular momentum and the hyperfine spin is conserved. Inside an Ioffe-Pritchard trap (IPT) whose magnetic field (B-field) is not axially symmetric, the difference of the two becomes surprisingly conserved. In this paper we investigate the relationship between the values of the sum/difference angular momentums for an atomic condensate inside a magnetic trap and the associated gauge potential induced by the adiabatic approximation. Our result provides significant new insight into the vorticity of magnetically trapped atomic quantum gases.
P. Zhang; H. H. Jen; C. P. Sun; L. You
Electron traps in organic light-emitting diodes
This work presents the effects of electron traps in organic light-emitting diodes using a model which includes charge injection
Min-Jan Tsai; Hsin-Fei Meng
Effect of laser e LED radiations associated or not on dorsal cutaneous wound repair in a rodent model: histologic study.
??The aim of the present investigation was to evaluate histologically tissue repair on dorsal cutaneous wounds in a rodent model treated with Laser and/or LED,� (more)
Ana Paula Cavalcanti de Sousa
Dose coefficients and derived guidance and clinical decision levels for contaminated wounds
The NCRP Wound Model describing the retention of selected radionuclides at the site of a contaminated wound and their uptake into the transfer compartment has been combined with the ICRP element-specific systemic models for those radionuclides to derive dose coefficients for intakes via contaminated wounds. Those coefficients have been used to generate derived guidance levels (i.e., the activity in a wound that would result in an effective dose of 20 or 50 mSv, or in some cases, a committed organ equivalent dose of 500 mSv), and clinical decision levels (i.e., activity levels that would indicate the need for consideration of medical intervention to remove activity from the wound site or administration of decorporation therapy or both), typically set at 5 times the derived guidance levels. Data are provided for the radionuclides commonly encountered at nuclear power plants and nuclear weapons, fuel fabrication or recycling, waste disposal, medical and research facilities. These include: {sup 60}Co, {sup 90}Sr, {sup 99m}Tc, {sup 131}I, {sup 137}Cs, {sup 192}Ir, {sup 210}Po, {sup 226,228}Ra, {sup 228,232}Th, {sup 235,238}U, {sup 237}Np, {sup 238,239}Pu, {sup 241}Am, {sup 242,244}Cm, and {sup 252}Cf.
Bertelli, Luiz [Los Alamos National Laboratory; Toohey, Richard E [ORISE/ORAU; Sugarman, Steven A [ORISE/ORAU; Christensen, Doran R [ORISE/ORAU
Selection, Sizing, and Testing of Stream Traps in Commercial Buildings
For maximum effectiveness in steam systems, steam traps should have operating characteristics which closely match the requirements of the applications for which they are used. A trap which holds back condensate until it is subcooled and some of the sensible heat has been utilized is unsuitable where the need is to get maximum output from an exchanger by discharging condensate as soon as it forms. Equally, a trap discharging condensate at steam temperature can exacerbate flash steam problems in cases where surplus heat exchange area exists and a subcooling trap might be more suitable. In all cases, undersized traps simply cannot drain condensate from the steam equipment at the required rate, while oversized traps which cost more will usually wear faster and begin leaking expensive steam. This emphasizes the need for carefully selecting trap sizes that are properly engineered for maximum system efficiency. And, of course, the ability of a trap to cope with varying loads and to discharge noncondensible gases is often important. The recommended procedure is to first select the trap type which has performance capabilities that satisfy specific application needs, and then to choose a size which handles the condensate load without any unnecessary excess capacity. The Selection Guide, Table 1, is not comprehensive but helps in many applications where no unusual operating conditions or severe corrosion problems exist. Choosing the correct trap size then implies estimating the steam consumption rate, which of course equals the condensate load. Sometimes the load has already been measured, or the rated output of the steam equipment is known or can be obtained from the original manufacturer. In other cases, an estimate must be made and a Table o f Load Formulas will help although it, too, cannot be comprehensive. After making the best possible estimate of the load, a safety factor is applied. This allows for any inaccuracies in the estimating, for increased condensation rates at start-up, and for lower than anticipated pressure differentials across the trap.
Armer, A.; Risko, J. R.
Debris trap in a turbine cooling system
In a turbine having a rotor and a plurality of stages, each stage comprising a row of buckets mounted on the rotor for rotation therewith; and wherein the buckets of at least one of the stages are cooled by steam, the improvement comprising at least one axially extending cooling steam supply conduit communicating with an at least partially annular steam supply manifold; one or more axially extending cooling steam feed tubes connected to the manifold at a location radially outwardly of the cooling steam supply conduit, the feed tubes arranged to supply cooling steam to the buckets of at least one of the plurality of stages; the manifold extending radially beyond the feed tubes to thereby create a debris trap region for collecting debris under centrifugal loading caused by rotation of the rotor.
Wilson, Ian David (Clifton Park, NY)
Can aerosols be trapped in open flows?
The fate of aerosols in open flows is relevant in a variety of physical contexts. Previous results are consistent with the assumption that such finite-size particles always escape in open chaotic advection. Here we show that a different behavior is possible. We analyze the dynamics of aerosols both in the absence and presence of gravitational effects, and both when the dynamics of the fluid particles is hyperbolic and nonhyperbolic. Permanent trapping of aerosols much heavier than the advecting fluid is shown to occur in all these cases. This phenomenon is determined by the occurrence of multiple vortices in the flow and is predicted to happen for realistic particle-fluid density ratios.
Rafael D. Vilela; Adilson E. Motter
Hydrobiologia vol. 65, I, pag. 65-68, 1979 A SIZE SELECTIVE UNDERWATER LIGHT TRAP
Hydrobiologia vol. 65, I, pag. 65-68, 1979 A SIZE SELECTIVE UNDERWATER LIGHT TRAP R. B. AIKEN underwater light trap isdescribed. Trap records indicate that the trap iseffective in taking a wide variety. (1955) described the construction and operation of an underwater light trap. Their records indi- cate
Aiken, Ron
Effective Steam Trap Selection/Maintenance - Its Payback
In oil refineries and petrochemical plants large number of steam traps are used to discharge condensate from steam mains, tracers and process equipment. Early efforts on steam traps focused almost exclusively on their selection and sizing, and it was not until the 1973 oil embargo that a need for regular maintenance became recognized. Although relatively small pieces of equipment, traps are responsible for large quantities of steam losses, decreased equipment efficiency and high maintenance costs; e.g., a steam trap leaking 100 psig steam through a 1/8 inch orifice costs at least $2k/yr if steam is valued at $5/k lb. Typically, a steam trap survey identifies 20-60% of traps malfunctioning. Therefore, establishing an effective steam trap selection/maintenance program is not simple but can be extremely profitable. This paper will show how a successful checking/maintenance program can result in high returns by using a case study at an Exxon plant. The example also shows how a central engineering organization can interact with plant technicians/ maintenance personnel to help implement an effective steam trap maintenance program at competitive costs and high returns.
Garcia, E.
Energy Efficient Steam Trapping of Trace Heating Systems
Since as many as 40-60% of a plant's steam traps may be used on steam tracer lines, it is essential to select the correct, properly sized 'traps'; to optimize the efficient removal of condensate while providing maximum heat transfer to maintain desired product temperatures and greatly reduce steam losses. Factors related to achieving uniform product temperatures and maximum heat transfer rates and energy efficiency are: 1.Types and Methods used for Steam Tracing; 2. Systematic heat balance required to achieve economic tracer lengths; 3. Maximum allowable trapping distance for specific applications 4.Data important to determine condensate loads; 5. Trap selection, sizing, good installation practices, and proper maintenance. Using an engineered approach to steam trapping of trace heating systems have resulted in stable tracer line temperatures while reducing steam consumption 10-50% with minimum maintenance.
Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator
Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped electrons. Next, the sixth chapter introduces suggestions for future trapped electron experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to electron trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel plasma, which if produced could solve some of the remaining issues for a plasma-based collider.
Kirby, Neil; /SLAC
Measurements of electric field noise and light-induced charging in cryogenic surface electrode ion traps
Ion traps provide an excellent tool for controlling and observing the state of a single trapped ion. For this reason, ion traps have been proposed as a possible system for large-scale quantum computation. However, many ...
Lachenmyer, Nathan S. (Nathan Scott)
Using malaise traps to sample ground beetles (Coleoptera: Carabidae).
Pitfall traps provide an easy and inexpensive way to sample ground-dwelling arthropods (Spence and Niemela 1994; Spence et al. 1997; Abildsnes and Tommeras 2000) and have been used exclusively in many studies of the abundance and diversity of ground beetles (Coleoptera: Carabidae). Despite the popularity of this trapping technique, pitfall traps have many disadvantages. For example, they often fail to collect both small (Spence and Niemela 1994) and �?¢�?�?�?�?trap-shy�?¢�?�?�? species (Benest 1989), eventually deplete the local carabid population (Digweed et al. 1995), require a species to be ground-dwelling in order to be captured (Liebherr and Mahar 1979), and produce different results depending on trap diameter and material, type of preservative used, and trap placement (Greenslade 1964; Luff 1975; Work et al. 2002). Further complications arise from seasonal patterns of movement among the beetles themselves (Maelfait and Desender 1990), as well as numerous climatic factors, differences in plant cover, and variable surface conditions (Adis 1979). Because of these limitations, pitfall trap data give an incomplete picture of the carabid community and should be interpreted carefully. Additional methods, such as use of Berlese funnels and litter washing (Spence and Niemela 1994), collection from lights (Usis and MacLean 1998), and deployment of flight intercept devices (Liebherr and Mahar 1979; Paarmann and Stork 1987), should be incorporated in surveys to better ascertain the species composition and relative numbers of ground beetles. Flight intercept devices, like pitfall traps, have the advantage of being easy to use and replicate, but their value to carabid surveys is largely unknown. Here we demonstrate the effectiveness of Malaise traps for sampling ground beetles in a bottomland hardwood forest.
Ulyshen, Michael D., James L. Hanula, and Scott Horn
Progress towards high precision measurements on ultracold metastable hydrogen and trapping deuterium
(cont.) not achieve deuterium trapping through helium-surface cooling. It is proposed that buffer gas loading can be used to cryogenically cool and trap deuterium.
Steinberger, Julia K., 1974-
Double-well magnetic trap for Bose-Einstein condensates
We present a magnetic trapping scheme for neutral atoms based on a hybrid of Ioffe-Pritchard and Time-averaged Orbiting Potential traps. The resulting double-well magnetic potential has readily controllable barrier height and well separation. This offers a new tool for studying the behavior of Bose condensates in double-well potentials, including atom interferometry and Josephson tunneling. We formulate a description for the potential of this magnetic trap and discuss practical issues such as loading with atoms, evaporative cooling and manipulating the potential.
N. R. Thomas; C. J. Foot; A. C. Wilson
Steam Trap Testing and Evaluation: An Actual Plant Case Study
With rising steam costs and a high failure rate on the Joliet Plants standard steam trap, a testing and evaluation program was begun to find a steam trap that would work at Olin-Joliet. The basis was to conduct the test on the actual process equipment and that a minimum life be achieved. This paper deals with the history of the steam system/condensate systems, the setting up of the testing procedure, which traps were and were not tested and the results of the testing program to date.
Feldman, A. L.
Extracellular nonmitogenic angiogenesis factor and method of isolation thereof from wound fluid
A nonmitogenic angiogenesis factor is isolated from wound fluid by dialysis to include materials in the molecular size range of 2,000 to 14,000, lyophilization, and chromatography. The nonmitogenic angiogenesis factor is identified by activity by corneal implant assay and by cell migration assay. The angiogenesis factor is also characterized by inactivity by mitogenesis assay.
Banda, Michael J. (San Francisco, CA); Werb, Zena (San Francisco, CA); Knighton, David R. (San Francisco, CA); Hunt, Thomas K. (San Francisco, CA)
Characterization of wound monitoring systems used to quantify and locate plutonium contamination
When an accident involving the possibility of a plutonium contaminated wound occurs, the contamination is often quantified using sodium iodide (NaI(Tl)) and high purity germanium (HPGe) detection systems. The NaI(Tl) system is used to quantify the amount of contamination, while HPGe is used to gauge the depth of contamination in the wound. Assessment of plutonium contaminated wounds is difficult due to the lowenergy and yield of the uranium L-shell x rays used for the measurement, which can be effected by source distance, shape, and tissue attenuation. These effects on wound counting systems used at Los Alamos National Laboratory (LANL) were characterized experimentally using common source shapes (disk, point, and line) and acrylic plastic as a tissue substitute. Experiments were conducted to characterize detector responses as a function of tissue attenuation, source distance, and source depth in tissue. The computer code MCNP5 was used to model both systems for wound counting and better examine angular displacement of a line source in tissue. The NaI(Tl) detector response was characterized using absolute detector efficiency for all experimental measurements. Measurements showed that the NaI(Tl) system is significantly effected by the source to detector position and depth in tissue. Characterization of the HPGe detection system was done utilizing the peak-to-peak ratio from the two low-energy x rays. HPGe peak-to-peak ratios were not affected by source to detector distance, but showed an increased response to source depth in tissue. MCNP results suggested that small incident angles from the plane of the detector face can cause significant effects on the response of both detectors. In summary, the response of both systems showed dependence on source geometry and depth of contamination in tissue. Correction values and uncertainties were determined based on these dependencies.
Dimmerling, Paul James
Fuel traps: mapping stability via water association.
Hydrogen storage is a key enabling technology required for attaining a hydrogen-based economy. Fundamental research can reveal the underlying principles controlling hydrogen uptake and release by storage materials, and also aid in characterizing and designing novel storage materials. New ideas for hydrogen storage materials come from exploiting the properties of hydrophobic hydration, which refers to water s ability to stabilize, by its mode of association, specific structures under specific conditions. Although hydrogen was always considered too small to support the formation of solid clathrate hydrate structures, exciting new experiments show that water traps hydrogen molecules at conditions of low temperatures and moderate pressures. Hydrogen release is accomplished by simple warming. While these experiments lend credibility to the idea that water could form an environmentally attractive alternative storage compound for hydrogen fuel, which would advance our nation s goals of attaining a hydrogen-based economy, much work is yet required to understand and realize the full potential of clathrate hydrates for hydrogen storage. Here we undertake theoretical studies of hydrogen in water to establish a firm foundation for predictive work on clathrate hydrate H{sub 2} storage capabilities. Using molecular simulation and statistical mechanical theories based in part on quantum mechanical descriptions of molecular interactions, we characterize the interactions between hydrogen and liquid water in terms of structural and thermodynamic properties. In the process we validate classical force field models of hydrogen in water and discover new features of hydrophobic hydration that impact problems in both energy technology and biology. Finally, we predict hydrogen occupancy in the small and large cages of hydrogen clathrate hydrates, a property unresolved by previous experimental and theoretical work.
Rempe, Susan L.; Clawson, Jacalyn S.; Greathouse, Jeffery A.; Alam, Todd M; Leung, Kevin; Varma, Sameer; Sabo, Dubravko; Martin, Marcus Gary; Cygan, Randall Timothy
Purple traps yield Reservation's first detection of Emerald Ash Borer
traps yield Reservation's first detection of Emerald Ash Borer traps yield Reservation's first detection of Emerald Ash Borer The question of whether or not DOE's forests are infested with Emerald Ash Borer (EAB) has been answered. On May 10, a trap on Highway 95 at the Highway 58 interchange produced the first instance of the destructive non-native insect in Roane County. Five days later, a second trap on Bethel Valley Road near the East Portal turned up the first capture in Anderson County. "Unfortunately, these finds signal the beginning of a decline of ash species throughout the reservation" according to Greg Byrd, forester with the ORNL Natural Resources Program. "Dieback will become more prominent as the insect populations expand. Native ash trees have little defense against this pest, which was
Energy Conservation in Coastal-Trapped Wave Calculations
A consideration of energy conservation for coastal-trapped waves shows that, for a slowly varying medium, the normalization of the wave modes is not arbitrary. Errors related to incorrect normalization are demonstrated for a simple analytic ...
K. H. Brink
Energy Trapping near the Equator in a Numerical Ocean Model
The trapped equatorial standing modes described theoretically by Gent (1979) are reproduced in a single vertical-mode numerical ocean model. integrations are carried out in domains whose longitudinal extents are characteristic of the widths of ...
Peter R. Gent; Albert J. Semtner Jr.
Trapped Lee Wave Interference in the Presence of Surface Friction
Trapped lee wave interference over double bell-shaped obstacles in the presence of surface friction is examined. Idealized high-resolution numerical experiments with the nonhydrostatic Coupled Ocean�Atmosphere Mesoscale Prediction System (COAMPS) ...
Ivana Stiperski; Vanda Grubi�i?
Gravity-induced resonances in a rotating trap
It is shown that in an anisotropic harmonic trap that rotates with the properly chosen rotation rate, the force of gravity leads to a resonant behavior. Full analysis of the dynamics in an anisotropic, rotating trap in 3D is presented and several regions of stability are identified. On resonance, the oscillation amplitude of a single particle, or of the center of mass of a many-particle system (for example, BEC), grows linearly with time and all particles are expelled from the trap. The resonances can only occur when the rotation axis is tilted away from the vertical position. The positions of the resonances (there are always two of them) do not depend on the mass but only on the characteristic frequencies of the trap and on the direction of the angular velocity of rotation.
Iwo Bialynicki-Birula; Tomasz Sowinski
From transistor to trapped-ion computers for quantum chemistry
Over the last few decades, quantum chemistry has progressed through the development of computational methods based on modern digital computers. However, these methods can hardly fulfill the exponentially-growing resource requirements when applied to large quantum systems. As pointed out by Feynman, this restriction is intrinsic to all computational models based on classical physics. Recently, the rapid advancement of trapped-ion technologies has opened new possibilities for quantum control and quantum simulations. Here, we present an efficient toolkit that exploits both the internal and motional degrees of freedom of trapped ions for solving problems in quantum chemistry, including molecular electronic structure, molecular dynamics, and vibronic coupling. We focus on applications that go beyond the capacity of classical computers, but may be realizable on state-of-the-art trapped-ion systems. These results allow us to envision a new paradigm of quantum chemistry that shifts from the current transistor to a near-future trapped-ion-based technology.
M. -H. Yung; J. Casanova; A. Mezzacapo; J. McClean; L. Lamata; A. Aspuru-Guzik; E. Solano
A Model for Vortex-Trapped Internal Waves
Regions of negative vorticity are observed to trap and amplify near-inertial internal waves, which are sources of turbulent mixing 10�100 times higher than typically found in the stratified ocean interior. Because these regions are of finite ...
Eric Kunze; Emmanuel Boss
On the Damping of Free Coastal-Trapped Waves
A perturbative method is presented for estimating the decay time of subinertial coastal-trapped waves under a wide range of conditions where damping is relatively weak. Bottom friction is sometimes much more important than �long-wave� results ...
Electron source for a mini ion trap mass spectrometer
An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.
Dietrich, D.D.; Keville, R.F.
Trapped Ion Imaging with a High Numerical Aperture Spherical Mirror
Efficient collection and analysis of trapped ion qubit fluorescence is essential for robust qubit state detection in trapped ion quantum computing schemes. We discuss simple techniques of improving photon collection efficiency using high numerical aperture (N.A.) reflective optics. To test these techniques we placed a spherical mirror with an effective N.A. of about 0.9 inside a vacuum chamber in the vicinity of a linear Paul trap. We demonstrate stable and reliable trapping of single barium ions, in excellent agreement with our simulations of the electric field in this setup. While a large N.A. spherical mirror introduces significant spherical aberration, the ion image quality can be greatly improved by a specially designed aspheric corrector lens located outside the vacuum system. Our simulations show that the spherical mirror/corrector design is an easy and cost-effective way to achieve high photon collection rates when compared to a more sophisticated parabolic mirror setup.
G Shu; M R Dietrich; N Kurz; B B Blinov
Shu, G; Kurz, N; Blinov, B B
Life Cycle of a Linear Coastal-Trapped Disturbance
A recent climatology of observed coastal-trapped disturbances in the marine atmospheric boundary layer along the United States west coast motivates the detailed examination, for a specific form of imposed forcing, of a linear shallow-water ...
R. M. Samelson; A. M. Rogerson
Light trapping limits in plasmonic solar cells: an analytical investigation
We analytically investigate the light trapping performance in plasmonic solar cells with Si/metallic structures. We consider absorption enhancements for surface plasmon polaritons (SPPs) at planar Si/metal interfaces and ...
Sheng, Xing
Novel trapping techniques for shaping Bose-Einstein condensates
A combination of radio frequency radiation and magnetic field gradients was used to trap atoms in dressed states. In a magnetic field with a quadrupole minimum. RF fields resonant with the (I F. m)) 11. -1) -- 1, 0) ...
Boyd, Micah (Micah Scott)
Quantum gates, sensors, and systems with trapped ions
Quantum information science promises a host of new and useful applications in communication, simulation, and computational algorithms. Trapped atomic ions are one of the leading physical systems with potential to implement ...
Heating of trapped ions from the quantum ground state
We have investigated motional heating of laser-cooled 9Be+ ions held in radio-frequency (Paul) traps. We have measured heating rates in a variety of traps with different geometries, electrode materials, and characteristic sizes. The results show that heating is due to electric-field noise from the trap electrodes which exerts a stochastic fluctuating force on the ion. The scaling of the heating rate with trap size is much stronger than that expected from a spatially uniform noise source on the electrodes (such as Johnson noise from external circuits), indicating that a microscopic uncorrelated noise source on the electrodes (such as fluctuating patch-potential fields) is a more likely candidate for the source of heating.
Q. A. Turchette; D. Kielpinski; B. E. King; D. Leibfried; D. M. Meekhof; C. J. Myatt; M. A. Rowe; C. A. Sackett; C. S. Wood; W. M. Itano; C. Monroe; D. J. Wineland
Dissipative trapped electron modes in ell = 2 torsatrons
Trapped electron modes in stellarators can be more unstable than those in tokamaks. They could be easier to detect in a stellarator and may be responsible for anomalous losses in the low collisionality regime. 5 refs., 1 fig.
Carreras, B.A.; Dominguez, N.; Lynch, V.E. (Oak Ridge National Lab., TN (USA)); Diamond, P.H. (California Univ., San Diego, CA (USA))
Laser-driven Sisyphus cooling in an optical dipole trap
We propose a laser-driven Sisyphus-cooling scheme for atoms confined in a far-off resonance optical dipole trap. Utilizing the differential trap-induced ac Stark shift, two electronic levels of the atom are resonantly coupled by a cooling laser preferentially near the trap bottom. After absorption of a cooling photon, the atom loses energy by climbing the steeper potential, and then spontaneously decays preferentially away from the trap bottom. The proposed method is particularly suited to cooling alkaline-earth-metal-like atoms where two-level systems with narrow electronic transitions are present. Numerical simulations for the cases of {sup 88}Sr and {sup 174}Yb demonstrate the expected recoil and Doppler temperature limits. The method requires a relatively small number of scattered photons and can potentially lead to phase-space densities approaching quantum degeneracy in subsecond time scales.
Ivanov, Vladyslav V.; Gupta, Subhadeep [Physics Department, University of Wisconsin, Madison, Wisconsin 53706 (United States); Physics Department, University of Washington, Seattle, Washington 98195 (United States)
Neutron lifetime measurements using gravitationally trapped ultracold neutrons
Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before:the probability of UCN losses from the trap was only 1% of that for neutron beta decay. The neutron lifetime obtained,878.5+/-0.7stat+/-0.3sys s, is the most accurate experimental measurement to date.
A. P. Serebrov; V. E. Varlamov; A. G. Kharitonov; A. K. Fomin; Yu. N. Pokotilovski; P. Geltenbort; I. A. Krasnoschekova; M. S. Lasakov; R. R. Taldaev; A. V. Vassiljev; O. M. Zherebtsov
Plant View On Reducing Steam Trap Energy Loss
Energy will continue to be an ever increasingly important factor in the cost of doing business in the decade of the 80' s. In many petrochemical industries, energy is the second most costly item in producing a product. About 36% of our nation's total energy consumption is used by industry in producing the goods which are consumed around the world. Steam is the most commonly used energy source for the petrochemical industry. Most of this steam is used for heating and evaporating the many petrochemical liquids. This steam is then condensed and is removed from the system at the same rate as it is being formed or the loss of heat transfer will result. From a cost standpoint only condensate should be allowed through the trap. But at many plants half of the steam traps are passing excess steam. This is caused by neglect of aged steam traps which have worn out and misapplication of steam traps by oversizing or using the 'wrong' type trap. Elimination of steam wastes by an effective well engineered steam trap program is what is covered by this article.
Vallery, S. J.
A Robust Four-Fluid Transient Flow Simulator as an Analysis and Decision Making Tool for Dynamic Kill Operation
The worst scenario of drilling operation is blowout which is uncontrolled flow of formation fluid into the wellbore. Blowouts result in environmental damage with potential risk of injuries and fatalities. Although not all blowouts result in disaster, outcomes of blowouts are unknown and should be studied before starting an operation. Plans should be available to prevent blowouts or provide safe and secure ways of controlling the well before the drilling operation starts. The plan should include procedures in case of any blowout incident as a proactive measure. A few commercial softwares are available in the industry for dynamic kill and transient modeling. All models are proprietary and very complex which reduces the flexibility of the program for specific cases. The purpose of this study is to develop a pseudo transient hydraulic simulator for dynamic kill operations. The idea and concept is to consider the flow of each phase as a single phase flow. The summation of hydrostatic and frictional pressure of each phase determines the bottomhole pressure during the dynamic kill operation. The simulator should be versatile and capable of handling special cases that may encounter during blowouts. Some of the main features of the proposed dynamic kill simulator include; quick and robust simulation, fluid properties are corrected for pressure and temperature, sensitivity analysis can be performed through slide bars, and capable of handling variety of wellbore trajectories. The results from the proposed simulator were compared to the result of commercial software, OLGA ABC. The results were in agreement with each other. It is recommended to apply the simulator for operations with required kill fluid volumes of one to two wellbore volumes.
Haghshenas, Arash
Trapping of antiprotons -- a first step on the way to antihydrogen
A first step towards producing and effectively utilizing antihydrogen atoms consists of trapping antiprotons. The immediate next step must then be to control, i.e. trap the produced antihydrogen. The current state of the art in trapping antiprotons and positrons is reviewed, and the challenges in trapping the resulting neutral particles are discussed.
Holzscheiter, M.H.
Ultrapdeep water blowouts: COMASim dynamic kill simulator validation and best practices recommendations
The petroleum industry is in a constant state of change. Few industries have advanced as far technologically as the petroleum industry has in its relatively brief existence. The produced products in the oil and gas industry are finite. As such, the easier to find and produce hydrocarbons are exploited first. This forces the industry to enter new areas and environments to continue supplying the world's hydrocarbons. Many of these new frontiers are in what is considered ultradeep waters, 5000 feet or more of water. While all areas of the oil and gas industry have advanced their ultradeep water technology, one area has had to remain at the forefront: drilling. Unfortunately, while drilling as a whole may be advancing to keep up with these environments, some segments lag behind. Blowout control is one of these areas developed as an afterthought. This lax attitude towards blowouts does not mean they are not a major concern. A blowout can mean injury or loss of life for rig personnel, as well as large economic losses, environmental damage and damage to the oil or gas reservoir itself. Obviously, up-to-date technology and techniques for the prevention and control of ultradeep water blowouts would be an invaluable part of any oil and gas company's exploration planning and technology suite. To further the development of blowout prevention and control, COMASim Cherokee Offshore, MMS, Texas A&M Simulator) was developed. COMASim simulates the planning and execution of a dynamic kill delivered to a blowout. Through a series of over 800 simulation runs, we were able to find several key trends in both the initial conditions as well as the kill requirements. The final phase of this study included a brief review of current industry deepwater well control best practices and how the COMASim results fit in with them. Overall, this study resulted in a better understanding of ultradeep water blowouts and what takes to control them dynamically. In addition to this understanding of blowouts, COMASim's strengths and weaknesses have now been exposed in order to further develop this simulator for industry use.
Noynaert, Samuel F.
System and method for trapping and measuring a charged particle in a liquid
A system and method for trapping a charged particle is disclosed. A time-varying periodic multipole electric potential is generated in a trapping volume. A charged particle under the influence of the multipole electric field is confined to the trapping volume. A three electrode configuration giving rise to a 3D Paul trap and a four planar electrode configuration giving rise to a 2D Paul trap are disclosed.
Reed, Mark A; Krstic, Predrag S; Guan, Weihua; Zhao, Xiongce
3D Thermal and Electrochemical Model for Spirally Wound Large Format Lithium-ion Batteries (Presentation)
In many commercial cells, long tabs at both cell sides, leading to uniform potentials along the spiral direction of wound jelly rolls, are rarely seen because of their high manufacturing cost. More often, several metal strips are welded at discrete locations along both current collector foils. With this design, the difference of electrical potentials is easily built up along current collectors in the spiral direction. Hence, the design features of the tabs, such as number, location and size, can be crucial factors for spiral-shaped battery cells. This paper presents a Li-ion battery cell model having a 3-dimensional spiral mesh involving a wound jellyroll structure. Further results and analysis will be given regarding impacts of tab location, number, and size.
Lee, K. J.; Kim, G. H.; Smith, K.
Normal-zone detection in tokamak superconducting magnets with Co- wound voltage sensors
This paper discusses advantages and disadvantages of different locations of co-wound voltage sensors for quench detection in tokamak magnets with a cable-in-conduit conductor. The voltage sensor locations are analyzed and estimates of the anticipated noise vs. dB/dt are derived for transverse, parallel, and self fields. The LLNL Noise Rejection Experiment, also described here, is designed to verify theoretical expectations on a copper cable exposed to these fields that will simulate the tokamak field environment.
Martovetsky, N.N.; Chaplin, M.R.
Three-Dimensional Thermal-Electrochemical Coupled Model for Spirally Wound Large-Format Lithium-Ion Batteries (Presentation)
This presentation discusses the behavior of spirally wound large-format Li-ion batteries with respect to their design. The objectives of the study include developing thermal and electrochemical models resolving 3-dimensional spirally wound structures of cylindrical cells, understanding the mechanisms and interactions between local electrochemical reactions and macroscopic heat and electron transfers, and developing a tool and methodology to support macroscopic designs of cylindrical Li-ion battery cells.
Lee, K. J.; Smith K.; Kim, G. H.
Trapped electron losses by interactions with coherent VLF waves
VLF whistler waves from lightning enter the magnetosphere and cause the precipitation of energetic trapped electrons by pitch angle scattering. These events, known as Lightning-induced Electron Precipitation (LEP) have been detected by satellite and rocket instruments and by perturbations of VLF waves traveling in the earth-ionosphere waveguide. Detailed comparison of precipitating electron energy spectra and time dependence are in general agreement with calculations of trapped electron interactions with ducted whistler waves. In particular the temporal structure of the precipitation and the dynamic energy spectra of the electrons confirm this interpretation of the phenomena. There are discrepancies between observed and measured electron flux intensities and pitch angle distributions, but these quantities are sensitive to unknown wave intensities and trapped particle fluxes near the loss cone angle. The overall effect of lightning generated VLF waves on the lifetime of trapped electrons is still uncertain. The flux of electrons deflected into the bounce loss cone by a discrete whistler wave has been measured in a few cases. However, the area of the precipitation region is not known, and thus the total number of electrons lost in an LEP event can only be estimated. While the LEP events are dramatic, more important effects on trapped electrons may arise from the small but numerous deflections which increase the pitch angle diffusion rate of the electron population. {copyright} {ital 1996 American Institute of Physics.}
Walt, M.; Inan, U.S. [Space, Telecommunications and Radioscience Laboratory, Stanford University, Stanford, California (United States); Voss, H.D. [Lockheed Missiles and Space Co. (United States)
Cosmological perturbations from inhomogeneous preheating and multi-field trapping
We consider inhomogeneous preheating in a multi-field trapping model. The curvature perturbation is generated by inhomogeneous preheating which induces multi-field trapping at the enhanced symmetric point (ESP), and results in fluctuation in the number of e-foldings. Instead of considering simple reheating after preheating, we consider a scenario of shoulder inflation induced by the trapping. The fluctuation in the number of e-foldings is generated during this weak inflationary period, when the additional light scalar field is trapped at the local maximum of its potential. The situation may look similar to locked or thermal inflation or even to hybrid inflation, but we will show that the present mechanism of generating the curvature perturbation is very different from these others. Unlike the conventional trapped inflationary scenario, we do not make the assumption that an ESP appears at some unstable point on the inflaton potential. This assumption is crucial in the original scenario, but it is not important in the multi-field model. We also discuss inhomogeneous preheating at late-time oscillation, in which the magnitude of the curvature fluctuation can be enhanced to accommodate low inflationary scale.
Tomohiro Matsuda
Storing Electrons Instead of Positrons Without Trapping of Positive Ions
Electrons Instead of Positrons Without Electrons Instead of Positrons Without Trapping of Positive Ions LS-75 T. K. Khoe October, 1986 In this note, a procedure to inject and store electrons in the ring without trapping ions will be described. The minimum injection current per bunch below which ion trapping occur will be determined. Since the vertical beam size is smaller than the horizontal beam size, we will consider the vertical motion only. The following assumptions are made: 1. The bunch period is much longer than the bunch length. This assumption allow us to use the thin lens approximation for the focusing effect of the electron bunch. 2. The bunch length is much larger than the transverse dimensions of the beam. A two-dimensional calculation can then be used to obtain the
Recent progress in tailoring trap-based positron beams
Recent progress is described to implement two approaches to specially tailor trap-based positron beams. Experiments and simulations are presented to understand the limits on the energy spread and pulse duration of positron beams extracted from a Penning-Malmberg (PM) trap after the particles have been buffer-gas cooled (or heated) in the range of temperatures 1000 {>=} T {>=} 300 K. These simulations are also used to predict beam performance for cryogenically cooled positrons. Experiments and simulations are also presented to understand the properties of beams formed when plasmas are tailored in a PM trap in a 5 tesla magnetic field, then non-adiabatically extracted from the field using a specially designed high-permeability grid to create a new class of electrostatically guided beams.
Natisin, M. R.; Hurst, N. C.; Danielson, J. R.; Surko, C. M. [Physics Department, University of California, San Diego La Jolla CA 92093-0319 (United States)
Formation of Antihydrogen Rydberg atoms in strong magnetic field traps
It is shown that several features of antihydrogen production in nested Penning traps can be described with accurate and efficient Monte Carlo simulations. It is found that cold deeply-bound Rydberg states of antihydrogen (H-bar) are produced in three-body capture in the ATRAP experiments and an additional formation mechanism -Rydberg charge transfer-, particular to the nested Penning trap geometry, is responsible for the observed fast (hot) H-bar atoms. Detailed description of the numerical propagation technique for following extreme close encounters is given. An analytic derivation of the power law behavior of the field ionization spectrum is provided.
Pohl, T.; Sadeghpour, H. R. [ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138 (United States)
Electron Trapping in Shear Alfven Waves that Power the Aurora
Results from 1D Vlasov drift-kinetic plasma simulations reveal how and where auroral electrons are accelerated along Earth's geomagnetic field. In the warm plasma sheet, electrons become trapped in shear Alfven waves, preventing immediate wave damping. As waves move to regions with larger v{sub Te}/v{sub A}, their parallel electric field decreases, and the trapped electrons escape their influence. The resulting electron distribution functions compare favorably with in situ observations, demonstrating for the first time a self-consistent link between Alfven waves and electrons that form aurora.
Watt, Clare E. J.; Rankin, Robert [University of Alberta, Edmonton, Alberta (Canada)
We have investigated motional heating of laser-cooled 9Be+ ions held inradio-frequency (Paul) traps. We have measured heating rates in a variety oftraps with different geometries, electrode materials, and characteristic sizes.The results show that heating is due to electric-field noise from the trapelectrodes which exerts a stochastic fluctuating force on the ion. The scalingof the heating rate with trap size is much stronger than that expected from aspatially uniform noise source on the electrodes (such as Johnson noise fromexternal circuits), indicating that a microscopic uncorrelated noise source onthe electrodes (such as fluctuating patch-potential fields) is a more likelycandidate for the source of heating.
Turchette, Q A; King, B E; Leibfried, D; Meekhof, D M; Myatt, C J; Rowe, M A; Sackett, C A; Wood, C S; Itano, W M; Monroe, C; Wineland, D J
Detection of Magnetically Trapped Neutrons: Liquid Helium as a Scintillator
by Daniel Nicholas McKinsey to The Department of Physics in partial fulfillment of the requirements February 2002 #12;c 2002 - Daniel Nicholas McKinsey All rights reserved. #12;To my parents #12;Thesis advisor Author John Morrissey Doyle Daniel Nicholas McKinsey Detection of Magnetically Trapped Neutrons
McKinsey, Daniel
Synthesis of Cold Antihydrogen in a Cusp Trap
We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.
Enomoto, Y.; Nagata, Y.; Kanai, Y.; Mohri, A. [RIKEN Advanced Science Institute, Hirosawa, Wako, Saitama 351-0198 (Japan); Kuroda, N.; Kim, C. H.; Torii, H. A.; Fujii, K.; Ohtsuka, M.; Tanaka, K.; Matsuda, Y. [Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro, Tokyo 153-8902 (Japan); Michishio, K.; Nagashima, Y. [Department of Physics, Tokyo University of Science, Kagurazaka, Shinjuku, Tokyo 162-8601 (Japan); Higaki, H. [Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8530 (Japan); Corradini, M.; Leali, M.; Lodi-Rizzini, E.; Mascagna, V.; Venturelli, L.; Zurlo, N. [Dipartimento di Chimica e Fisica per l'Ingegneria e per i Materiali, Universita di Brescia and Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Brescia, 25133 Brescia (Italy)
Manipulation and assembly of nanowires with holographic optical traps
We demonstrate that semiconductor nanowires measuring just a few nanometers in diameter can be translated, rotated, cut, fused and organized into nontrivial structures using holographic optical traps. The holographic approach to nano-assembly allows for simultaneous independent manipulation of multiple nanowires, including relative translation and relative rotation.
Ritesh Agarwal; Kosta Ladavac; Yael Roichman; Guiha Yu; Charles M. Lieber; David G. Grier
Z5, Effect of Traps Spatial Localization on GaN HEMT Static ...
Conference Tools for 2010 Electronic Materials Conference ... In this work we discuss how trap state formation during reverse gate-source and ... by means of the commercial DESSIS-ISE (Synopsis Inc.) simulator showed that acceptor traps
Observations of Seasonal Variations in Atmospheric Greenhouse Trapping and Its Enhancement at High Sea Surface Temperature
The correlation between observed values of atmospheric greenhouse trapping and sea surface temperature is found to vary seasonally. Atmospheric greenhouse trapping is defined here as the difference between infrared emissions from the earth's ...
Robert Hallberg; Anand K. Inamdar
Loading a planar RF Paul Trap from a cold Yb? source
In this thesis, we demonstrate a functioning planar radio frequency, three-rod Paul Trap, loaded with Yb+ ions that have been photoionized from a source of neutral atoms, which were cooled in a magneto-optical trap. Planar ...
Shields, Brendan John
Finite-geometry models of electric field noise from patch potentials in ion traps
We model electric field noise from fluctuating patch potentials on conducting surfaces by taking into account the finite geometry of the ion trap electrodes to gain insight into the origin of anomalous heating in ion traps. ...
Low, Guang Hao
Use of Bullet Traps and Steel Targets - June 4, 2012 | Department...
Use of Bullet Traps and Steel Targets - June 4, 2012 Use of Bullet Traps and Steel Targets - June 4, 2012 June 4, 2012 This supplement contains the currently approved document, Use...
Microfabricated surface ion trap on a high-finesse optical mirror
A novel approach to optics integration in ion traps is demonstrated based on a surface electrode ion trap that is microfabricated on top of a dielectric mirror. Additional optical losses due to fabrication are found to be ...
Herskind, Peter F.
Design of superconducting transmission line integrated surface-electrode ion-traps
We fabricated superconducting surface electrode ion traps with integrated microwave coplanar waveguides using direct-write optical lithography and a niobium on sapphire process. We then tested these traps in a closed cycle ...
Meyer, David Thomas
Mechanisms for Fluorescence Blinking and Charge Carrier Trapping in Single Semiconductor Nanocrystals
Trapping Mechanisms in Single CdSe/ZnS Quantum Dots fromTrapping Mechanisms in Single CdSe/ZnS Quantum Dots fromintermittency of single CdSe/ZnS core/shell quantum dot
Cordones, Amy Ashbrook
The Extension of Baroclinic Coastal-Trapped Wave Theory to Superinertial Frequencies
The problem of finding baroclinic coastal-trapped wave modes is generalized from subinertial to superinertial frequencies at which complete trapping can only occur in special cases. Modes are found by a numerical resonance searching method in ...
Andrew C. Dale; Toby J. Sherwin
Evaluation of Sorbent Trap Materials and Methods for Flue Gas Mercury Measurement
Sorbent traps are used as an alternative to continuous mercury monitors (CMM) for measuring vapor phase mercury concentrations in stacks of coal-fired power plants and for relative accuracy test audits (RATAs) of CMMs. EPRI has an ongoing program of research on sorbent trap methods, evaluating the performance of sorbent materials and the methods used to measure mercury on the sorbent traps. This report presents results of two investigations targeted at evaluating the performance of sorbent trap methods f...
Atom trapping in a bottle beam created by a diffractive optical element
A diffractive optical element (DOE) has been fabricated for creating blue detuned atomic bottle beam traps. The DOE integrates several diffractive lenses for trap creation and imaging of atomic fluorescence. We characterize the performance of the DOE and demonstrate trapping of cold Cesium atoms inside a bottle beam.
V. V. Ivanov; J. A. Isaacs; M. Saffman; S. A. Kemme; A. R. Ellis; G. R. Brady; J. R. Wendt; G. W. Biedermann; S. Samora
Ivanov, V V; Saffman, M; Kemme, S A; Ellis, A R; Brady, G R; Wendt, J R; Biedermann, G W; Samora, S
Abstract-Finite element stiffness and consistent mass matrices are derived for helically wound, symmetrical composite tubes. The tubular element is considered to have constant cross-section and small deformations restricted to a plane. Each node has three degrees of freedom: axial and transverse displacement and rotation (slope oftransverse displacement). Shell theory and lamination theory are used to formulate element stiffness matrices. The stiffness and mass matrices derived from the helically wound tubular composite material are reduced to symmetrically laminated composite beam. The free vibration and natural frequency are investigated for five different materials: steel, aluminum, carbon/N5280, Kevlar-49/epoxy and graphite/epoxy composites and various layup configurations. One application of a rotating flexible beam is investigated. The dynamic model of the flexible rotating beam includes the coupled effect between the rigid body motion and the flexible motion. The inverse dynamic simulation is performed by a prescribed driving torque in the numerical simulation. The influence of flexibility on rigid body motion are presented and discussed. From the numerical results, the composite material strongly possesses the lower power consumption and the passive control in damping the vibration of the structure. INTRODUcnON
C. I. Chen; V. H. Mucino; E. J. Barbero
Acemannan-containing wound dressing gel reduces radiation-induced skin reactions in C3H mice
To determine (a) whether a wound dressing gel that contains acemannan extracted from aloe leaves affects the severity of radiation-induced acute skin reactions in C3H mice; (b) if so, whether other commercially available gels such as a personal lubricating jelly and a healing ointment have similar effects; and (c) when the wound dressing gel should be applied for maximum effect. Male C3H mice received graded single doses of gamma radiation ranging from 30 to 47.5 Gy to the right leg. In most experiments, the gel was applied daily beginning immediately after irradiation. Dose-response curves were obtained by plotting the percentage of mice that reached or exceeded a given peak skin reaction as a function of dose. Curves were fitted by logit analysis and ED{sub 50} values, and 95% confidence limits were obtained. The average peak skin reactions of the wound dressing gel-treated mice were lower than those of the untreated mice at all radiation doses tested. The ED{sub 50} values for skin reactions of 2.0-2.75 were approximately 7 Gy higher in the wound dressing gel-treated mice. The average peak skin reactions and the ED{sub 50} values for mice treated with personal lubricating jelly or healing ointment were similar to irradiated control values. Reduction in the percentage of mice with skin reactions of 2.5 or more was greatest in the groups that received wound dressing gel for at least 2 weeks beginning immediately after irradiation. There was no effect if gel was applied only before irradiation or beginning 1 week after irradiation. Wound dressing gel, but not personal lubricating jelly or healing ointment, reduces acute radiation-induced skin reactions in C3H mice if applied daily for at least 2 weeks beginning immediately after irradiation. 31 refs., 4 figs., 1 tab.
Roberts, D.B.; Travis, E.L. [Univ. of Texas M.D. Anderson Cancer Center, Houston, TX (United States)
A Toy Model Study of Decay Trapping | Superconducting Magnet Division
A Toy Model Study of Decay Trapping, reported by Brett Parker A Toy Model Study of Decay Trapping, reported by Brett Parker Introduction A group from the BNL Superconducting Magnet Division is looking at various options for dipole magnets which would be suitable for use in a muon storage ring that is used as a neutrino factory. Since the useful neutrino beams from a neutrino factory come from straight sections it is desirable to minimize the rings arc circumference, in relation to straight section length, in order to ensure that the fraction of muons which decay in the straight section is as large as possible. Therefore superconducting magnets, with higher B-fields and smaller bend radii, are reasonable to consider for this application. Unfortunately the decay electrons generated along with the neutrinos carry on average about a third of the original
Photoionizing Trapped Highly Charged Ions with Synchrotron Radiation
Photoabsorption by highly charged ions plays an essential role in astrophysical plasmas. Diagnostics of photoionized plasmas surrounding binary systems rely heavily on precise identification of absorption lines and on the knowledge of their cross sections and widths. Novel experiments using an electron beam ion trap, FLASH EBIT, in combination with monochromatic synchrotron radiation allow us to investigate ions in charge states hitherto out of reach. Trapped ions can be prepared in any charge state at target densities sufficient to measure absorption cross sections below 0.1 Mb. The results benchmark state-of-the-art predictions of the transitions wavelengths, widths, and absolute cross sections. Recent high resolution results on Fe{sup 14+}, Fe{sup 15+}, and Ar{sup 12+} at photon energies up to 1 keV are presented.
Crespo, J R; Simon, M; Beilmann, C; Rudolph, J; Steinbruegge, R; Eberle, S; Schwarz, M; Baumann, T; Schmitt, B; Brunner, F; Ginzel, R; Klawitter, R; Kubicek, K; Epp, S; Mokler, P; Maeckel, V; Ullrich, J; Brown, G V; Graf, A; Leutenegger, M; Beiersdorfer, P; Behar, E; Follath, R; Reichardt, G; Schwarzkopf, O
Trapped Quintessential Inflation in the context of Flux Compactifications
We present a model for quintessential inflation using a string modulus for the inflaton - quintessence field. The scalar potential of our model is based on generic non-perturbative potentials arising in flux compactifications. We assume an enhanced symmetry point (ESP), which fixes the initial conditions for slow-roll inflation. When crossing the ESP the modulus becomes temporarily trapped, which leads to a brief stage of trapped inflation. This is followed by enough slow roll inflation to solve the flatness and horizon problems. After inflation, the field rolls down the potential and eventually freezes to a certain value because of cosmological friction. The latter is due to the thermal bath of the hot big bang, which is produced by the decay of a curvaton field. The modulus remains frozen until the present, when it becomes quintessence.
Umatilla River Basin Trap and Haul Program : Annual Report 1993.
Threemile Falls Dam is the major counting and collection point for adult salmonids returning to the Umatilla River. Returning salmon and steelhead were collected at Threemile Dam from October 23, 1992 to July 14, 1993. A total of 1,913 summer steelhead; 239 adult and 64 jack fall chinook; 355 adult and 174 jack coho; and 1,205 adult and 16 jack spring chinook were collected. Fish collected were hauled upstream from Threemile Dam using either a 370 or 3,000 gallon liberation unit. The Westland Canal facility, the major collection point for outmigrating juvenile salmonids and steelhead kelts was in operation from February 15 to July 29, 1993. During that period, fish were trapped 46 days. An estimated 3,228 pounds of fish were transported from the Westland Canal trap to the Umatilla River boat ramp at rivermile 0.5.
Zimmerman, Brian C.; Duke, Bill B.
Wolf Trap, Virginia: Energy Resources | Open Energy Information
Trap, Virginia: Energy Resources Trap, Virginia: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 38.9398329°, -77.286094° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":38.9398329,"lon":-77.286094,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Observation of cold Rb{sub 2} molecules trapped in an optical dipole trap using a laser-pulse-train technique
In this work, we have developed and characterized a laser-pulse-train technique to observe cold Rb{sub 2} molecules trapped in an optical dipole trap. The molecules are produced in a magneto-optical trap, and then loaded into a crossed optical dipole trap. The time evolution of the molecular population is obtained by applying a laser pulse train, which photoionizes the ground-state molecules through intermediate molecular bands. Our results show that this technique allows us to obtain a faster data acquisition rate of the time evolution of the molecule population than other techniques.
Menegatti, Carlos R.; Marangoni, Bruno S.; Marcassa, Luis G. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Caixa Postal 369, 13560-970, Sao Carlos, SP (Brazil)
Design and modeling of cylindrical and falt-wound lithium-ion cells for the PNGV application.
In this study, 10-Ah cylindrical and flat-wound cells were designed and studied for use in batteries for the Partnership for a New Generation of Vehicles (PNGV). A low-cost current collection system was devised that results in a low resistance. Heat rejection from flat cells is much better than that from cylindrical cells and is an important safety factor. Very compact, powerful batteries of about 1.5 kW/L can be designed with wound lithium-ion cells.
Nelson, P. A.; Henriksen, G. L.; Amine, K.
Persistent currents in Bose gases confined in annular traps
We examine the problem of stability of persistent currents in a mixture of two Bose gases trapped in an annular potential. We evaluate the critical coupling for metastability in the transition from quasi-one- to two-dimensional motion. We also evaluate the critical coupling for metastability in a mixture of two species as a function of the population imbalance. The stability of the currents is shown to be sensitive to the deviation from one-dimensional motion.
Bargi, S.; Malet, F.; Reimann, S. M. [Mathematical Physics, Lund Institute of Technology, P.O. Box 118, SE-22100 Lund (Sweden); Kavoulakis, G. M. [Technological Educational Institute of Crete, P.O. Box 1939, GR-71004, Heraklion (Greece)
Mixtures of Bose gases confined in concentrically coupled annular traps
A two-component Bose-Einstein condensate confined in an axially symmetric potential with two local minima, resembling two concentric annular traps, is investigated. The system shows a number of phase transitions that result from the competition between phase coexistence and radial-azimuthal phase separation. The ground-state phase diagram, as well as the rotational properties, including the (meta)stability of currents in this system, is analyzed.
Malet, F.; Reimann, S. M. [Mathematical Physics, LTH, Lund University, Post Office Box 118, SE-22100 Lund (Sweden); Kavoulakis, G. M. [Technological Education Institute of Crete, Post Office Box 1939, GR-71004, Heraklion (Greece)
Hydrogen trapping, diffusion, and recombination in austenitic stainless steels
Trapping, diffusion, and recombination of hydrogen in austenitic stainless steels are reviewed. It is suggested that since all of these processes are strongly interdependent and since the measured recombination rates are found to vary four orders of magnitude at any temperature, the data analysis techniques used to date are insufficient. A two-region diffusion model with surface recombination is proposed in which the surface layer is characterized by a smaller diffusion coefficient than the bulk.
Langley, R.A.
Observation of Spin Flips with a Single Trapped Proton
Radio-frequency induced spin transitions of one individual proton are observed. The spin quantum jumps are detected via the continuous Stern-Gerlach effect, which is used in an experiment with a single proton stored in a cryogenic Penning trap. This is an important milestone towards a direct high-precision measurement of the magnetic moment of the proton and a new test of the matter-antimatter symmetry in the baryon sector.
Ulmer, S. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Ruprecht Karls-Universitaet Heidelberg, D-69047 Heidelberg (Germany); Rodegheri, C. C. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Blaum, K. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Ruprecht Karls-Universitaet Heidelberg, D-69047 Heidelberg (Germany); Kracke, H.; Mooser, A.; Walz, J. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55099 Mainz (Germany); Helmholtz Institut Mainz, D-55099 Mainz (Germany); Quint, W. [Ruprecht Karls-Universitaet Heidelberg, D-69047 Heidelberg (Germany); GSI--Helmholtzzentrum fuer Schwerionenforschung, D-64291 Darmstadt (Germany)
Adiabatic trapping in coupled kinetic Alfven-acoustic waves
In the present work, we have discussed the effects of adiabatic trapping of electrons on obliquely propagating Alfven waves in a low {beta} plasma. Using the two potential theory and employing the Sagdeev potential approach, we have investigated the existence of arbitrary amplitude coupled kinetic Alfven-acoustic solitary waves in both the sub and super Alfvenic cases. The results obtained have been analyzed and presented graphically and can be applied to regions of space where the low {beta} assumption holds true.
Shah, H. A.; Ali, Z. [Department of Physics, G.C. University, 54000 Lahore (Pakistan); Masood, W. [COMSATS, Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 44000 (Pakistan); National Centre for Physics (NCP), Shahdara Valley Road, 44000 Islamabad (Pakistan); Theoretical Plasma Physics Division, P. O. Nilore, Islamabad (Pakistan)
Revolutionary systems for catalytic combustion and diesel catalytic particulate traps.
This report is a summary of an LDRD project completed for the development of materials and structures conducive to advancing the state of the art for catalyst supports and diesel particulate traps. An ancillary development for bio-medical bone scaffolding was also realized. Traditionally, a low-pressure drop catalyst support, such as a ceramic honeycomb monolith, is used for catalytic reactions that require high flow rates of gases at high-temperatures. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. ''Robocasting'' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low-pressure drops. These alternative 3-dimensional geometries may also provide a foundation for the development of self-regenerating supports capable of trapping and combusting soot particles from a diesel engine exhaust stream. This report describes the structures developed and characterizes the improved catalytic performance that can result. The results show that, relative to honeycomb monolith supports, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application. Practical applications include the combustion of natural gas for power generation, production of syngas, and hydrogen reforming reactions. The robocast lattice structures also show practicality for diesel particulate trapping. Preliminary results for trapping efficiency are reported as well as the development of electrically resistive lattices that can regenerate the structure by combusting the trapped soot. During this project an ancillary bio-medical application was discovered for lattices of hydroxyapatite. These structures show promise as bone scaffolds for the reparation of damaged bone. A case study depicting the manufacture of a customized device that fits into a damaged mandible is described.
Stuecker, John Nicholas; Witze, Peter O.; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward
Plasma outflow from a corrugated trap in the kinetic regime
The problem of stationary plasma outflow from an open corrugated trap in the kinetic regime is considered with allowance for pair collisions in the framework of a kinetic equation with the Landau collision integral. The distribution function is studied in the limit of small-scale corrugation and a large mirror ratio. In considering a single corrugation cell, a correction for the distribution function is calculated analytically. An equation describing variations of the distribution function along the system is derived and used to study the problem of plasma outflow into vacuum.
Skovorodin, D. I.; Beklemishev, A. D. [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation)
Laser cooling of a trapped particle with increased Rabi frequencies
This paper analyzes the cooling of a single particle in a harmonic trap with red-detuned laser light with fewer approximations than previously done in the literature. We avoid the adiabatic elimination of the excited atomic state but are still interested in Lamb-Dicke parameters {eta}cooling laser can be chosen higher than previously assumed, thereby increasing the effective cooling rate but not affecting the final outcome of the cooling process. Since laser cooling is already a well-established experimental technique, the main aim of this paper is to present a model which can be extended to more complex scenarios, like cavity-mediated laser cooling.
Blake, Tony; Kurcz, Andreas; Saleem, Norah S.; Beige, Almut [School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT (United Kingdom)
Hawking-like radiation does not require a trapped region
We discuss the issue of quasi-particle production by ``analogue black holes'' with particular attention to the possibility of reproducing Hawking radiation in a laboratory. By constructing simple geometric acoustic models, we obtain a somewhat unexpected result: We show that in order to obtain a stationary and Planckian emission of quasi-particles, it is not necessary to create a trapped region in the acoustic spacetime (corresponding to a supersonic regime in the fluid flow). It is sufficient to set up a dynamically changing flow asymptotically approaching a sonic regime with sufficient rapidity in laboratory time.
Carlos Barcelo; Stefano Liberati; Sebastiano Sonego; Matt Visser
Anti-hydrogen production with positron beam ion trap
In low-energy antiproton physics, it is advantageous to be able to manipulate anti-particles as freely as normal particles. A robust production and storage system for high-quality positrons and antiprotons would be a substantial advance for the development of anti-matter science. The idea of electron beam ion trap could be applied for storage of anti-particle when the electron beam could be replaced by the positron beam. The bright positron beam would be brought about using synchrotron radiation source with a superconducting wiggler. The new scheme for production of anti-particles is proposed by using new accelerator technologies.
Itahashi, Takahisa [Department of Physics, Graduate School of Science, Osaka University 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
Selective control of the symmetric Dicke subspace in trapped ions
We propose a method of manipulating selectively the symmetric Dicke subspace in the internal degrees of freedom of N trapped ions. We show that the direct access to ionic-motional subspaces, based on a suitable tuning of motion-dependent ac Stark shifts, induces a two-level dynamics involving previously selected ionic Dicke states. In this manner, it is possible to produce, sequentially and unitarily, ionic Dicke states with increasing excitation number. Moreover, we propose a probabilistic technique to produce directly any ionic Dicke state assuming suitable initial conditions.
Lopez, C. E.; Retamal, J. C. [Departamento de Fisica, Universidad de Santiago de Chile, Casilla 307 Correo 2, Santiago (Chile); Solano, E. [Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado 1761, Lima (Peru)
Selective interactions in trapped ions: State reconstruction and quantum logic
We propose the implementation of selective interactions of atom-motion subspaces in trapped ions. These interactions yield resonant exchange of population inside a selected subspace, leaving the others in a highly dispersive regime. Selectivity allows us to generate motional Fock (and other nonclassical) states with high purity out of a wide class of initial states, and becomes an unconventional cooling mechanism when the ground state is chosen. Individual population of number states can be distinctively measured, as well as the motional Wigner function. Furthermore, a protocol for implementing quantum logic through a suitable control of selective subspaces is presented.
Solano, E. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany and Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado 1761, Lima (Peru)
Energy trapping and shock disintegration in a composite granular medium
Granular materials demonstrate a strongly nonlinear behavior influencing the wave propagation in the medium. We report the first experimental observation of impulse energy confinement and the resultant disintegration of shock and solitary waves. The medium consists of alternating ensambles of high-modulus vs orders of magnitude lower modulus chains of different masses. The trapped energy is contained within the "softer" portions of the composite chain and is slowly released in the form of weak, separated pulses over an extended period of time. This effect is enhanced by using a specific group assembly and superimposed force.
C. Daraio; V. F. Nesterenko; E. B. Herbold; S. Jin
Nuclear spin qubits in a trapped-ion quantum computer
Physical systems must fulfill a number of conditions to qualify as useful quantum bits (qubits) for quantum information processing, including ease of manipulation, long decoherence times, and high fidelity readout operations. Since these conditions are hard to satisfy with a single system, it may be necessary to combine different degrees of freedom. Here we discuss a possible system, based on electronic and nuclear spin degrees of freedom in trapped ions. The nuclear spin yields long decoherence times, while the electronic spin, in a magnetic field gradient, provides efficient manipulation, and the optical transitions of the ions assure a selective and efficient initialization and readout.
M. Feng; Y. Y. Xu; F. Zhou; D. Suter
Ionization Induced Trapping in a Laser Wakefield Accelerator
Experimental studies of electrons produced in a laser wakefield accelerator indicate trapping initiated by ionization of target gas atoms. Targets composed of helium and controlled amounts of various gases were found to increase the beam charge by as much as an order of magnitude compared to pure helium at the same electron density and decrease the beam divergence from 5.1+-1.0 to 2.9+-0.8 mrad. The measurements are supported by particle-in-cell modeling including ionization. This mechanism should allow generation of electron beams with lower emittance and higher charge than in preionized gas.
McGuffey, C.; Thomas, A. G. R.; Schumaker, W.; Matsuoka, T.; Chvykov, V.; Dollar, F. J.; Kalintchenko, G.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K.; Bychenkov, V. Yu.; Glazyrin, I. V.; Karpeev, A. V. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); P. N. Lebedev Physics Institute, Russian Academy of Science, Leninskii Prospect 53, Moscow 119991 (Russian Federation); RFNC-VNIITF, Snezhinsk 456770, Chelyabinsk region (Russian Federation)
Quantum mechanics of one-dimensional trapped Tonks gases
Several experimental groups are currently working towards realizing quasi-one-dimensional (1D) atom waveguides and loading them with ultracold atoms. The dynamics becomes truly 1D in a regime (Tonks gas) of low temperatures and densities and large positive scattering lengths for which the transverse mode becomes frozen, in which case the many-body Schrodinger dynamics becomes exactly soluble via a Fermi-Bose mapping theorem. In this paper we review our recent work on the exact ground state and quantum dynamics of 1D Tonks gases and assess the possibility of approaching the Tonks regime using Bessel beam optical dipole traps.
M. D. Girardeau; E. M. Wright
Reliable transport through a microfabricated X-junction surface-electrode ion trap
We report the design, fabrication, and characterization of a microfabricated surface-electrode ion trap that supports controlled transport through the two-dimensional intersection of linear trapping zones arranged in a ninety-degree cross. The trap is fabricated with very-large-scalable-integration (VLSI) techniques which are compatible with scaling to a larger quantum information processor. The shape of the radio-frequency (RF) electrodes is optimized with a genetic algorithm to minimize axial pseudopotential barriers and to minimize ion heating during transport. Seventy-eight independent DC control electrodes enable fine control of the trapping potentials. We demonstrate reliable ion transport between junction legs, trapping of ion chains with nearly-equal spacing in one of the trap's linear sections, and merging and splitting ions from these chains. Doppler-cooled ions survive more than 10^5 round-trip transits between junction legs without loss and more than sixty-five consecutive round trips without laser cooling.
Kenneth Wright; Jason M. Amini; Daniel L. Faircloth; Curtis Volin; S. Charles Doret; Harley Hayden; C. -S. Pai; David W. Landgren; Douglas Denison; Tyler Killian; Richart E. Slusher; Alexa W. Harter
Characterization of a Dominant Electron Trap in GaNAs Using Deep-Level Spectroscopy
Dilute-nitrogen GaNAs epitaxial layers grown by metal-organic chemical vapor deposition were characterized by deep-level transient spectroscopy (DLTS). For all samples, the dominant DLTS signal corresponds to an electron trap having an activation energy of about 0.25 to 0.35 eV. The minority-carrier trap density in the p-type material is quantified based on computer simulation of the devices. The simulations show that only about 2% of the traps in the depleted layer are filled during the transient. The fraction of the traps that are filled depends strongly on the depth of the trap, but only weakly on the doping of the layers and on the conduction-band offset. The simulations provide a pathway to obtain semi-quantitative data for analysis of minority-carrier traps by DLTS.
Johnston, S. W.; Kurtz, S. R.
To:... Subject: Electromagnetic Impact of CEBAF Beam on Hydrogen Trap EXPECTED IMPACT OF CEBAF BEAM ON HYDROGEN TRAP
A magnetic ultra-cold trap of fully polarized atomic hydrogen is being considered for using as a target for M�ller polarimetry at CEBAF, at beam currents up to 100 �A. This note addresses possible problems caused by the CEBAF beam impact on such a target. The beam current generates an electromagnetic RF radiation which may cause a target depolarization inducing spin flips. Also, a part of the radiation may be absorbed in the cell pipe, heating it. The beam also heats up the gas by ionization. 1
unknown authors
Self-trapping dynamics in a 2D optical lattice
We describe theoretical models for the recent experimental observation of Macroscopic Quantum Self-Trapping (MQST) in the transverse dynamics of an ultracold bosonic gas in a 2D lattice. The pure mean-field model based on the solution of coupled nonlinear equations fails to reproduce the experimental observations. It greatly overestimates the initial expansion rates at short times and predicts a slower expansion rate of the cloud at longer times. It also predicts the formation of a hole surrounded by a steep square fort-like barrier which was not observed in the experiment. An improved theoretical description based on a simplified Truncated Wigner Approximation (TWA), which adds phase and number fluctuations in the initial conditions, pushes the theoretical results closer to the experimental observations but fails to quantitatively reproduce them. An explanation of the delayed expansion as a consequence of a new type of self-trapping mechanism, where quantum correlations suppress tunneling even when there are no density gradients, is discussed and supported by numerical time-dependent Density Matrix Renormalization Group (t-DMRG) calculations performed in a simplified two coupled tubes set-up.
Shuming Li; Salvatore R. Manmana; Ana Maria Rey; Rafael Hipolito; Aaron Reinhard; Jean-F�lix Riou; Laura A. Zundel; David S. Weiss
The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60-750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the sub-cutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.
Adriani, O. [Department of Physics, University of Florence, I-50019 Sesto Fiorentino, Florence (Italy); Barbarino, G. C. [Department of Physics, University of Naples 'Federico II', I-80126 Naples (Italy); Bazilevskaya, G. A. [Lebedev Physical Institute, RU-119991, Moscow (Russian Federation); Bellotti, R.; Bruno, A.; Cafagna, F. [Department of Physics, University of Bari, I-70126 Bari (Italy); Boezio, M.; Bonvicini, V. [INFN, Sezione di Trieste, I-34149 Trieste (Italy); Bogomolov, E. A. [Ioffe Physical Technical Institute, RU-194021 St. Petersburg (Russian Federation); Bongi, M.; Bottai, S. [INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence (Italy); Borisov, S.; Casolino, M.; De Pascale, M. P.; De Santis, C. [INFN, Sezione di Rome 'Tor Vergata', I-00133 Rome (Italy); Campana, D.; Carbone, R.; Consiglio, L. [INFN, Sezione di Naples, I-80126 Naples (Italy); Carlson, P. [KTH, Department of Physics, and the Oskar Klein Centre for Cosmoparticle Physics, AlbaNova University Centre, SE-10691 Stockholm (Sweden); Castellini, G., E-mail: firstname.lastname@example.com [IFAC, I-50019 Sesto Fiorentino, Florence (Italy)
The discovery of geomagnetically trapped cosmic ray antiprotons
The existence of a significant flux of antiprotons confined to Earth's magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60--750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the sub-cutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.
O. Adriani; G. C. Barbarino; G. A. Bazilevskaya; R. Bellotti; M. Boezio; E. A. Bogomolov; M. Bongi; V. Bonvicini; S. Borisov; S. Bottai; A. Bruno; F. Cafagna; D. Campana; R. Carbone; P. Carlson; M. Casolino; G. Castellini; L. Consiglio; M. P. De Pascale; C. De Santis; N. De Simone; V. Di Felice; A. M. Galper; W. Gillard; L. Grishantseva; G. Jerse; A. V. Karelin; M. D. Kheymits; S. V. Koldashov; S. Y. Krutkov; A. N. Kvashnin; A. Leonov; V. Malakhov; L. Marcelli; A. G. Mayorov; W. Menn; V. V. Mikhailov; E. Mocchiutti; A. Monaco; N. Mori; N. Nikonov; G. Osteria; F. Palma; P. Papini; M. Pearce; P. Picozza; C. Pizzolotto; M. Ricci; S. B. Ricciarini; L. Rossetto; R. Sarkar; M. Simon; R. Sparvoli; P. Spillantini; Y. I. Stozhkov; A. Vacchi; E. Vannuccini; G. Vasilyev; S. A. Voronov; Y. T. Yurkin; J. Wu; G. Zampa; N. Zampa; V. G. Zverev
Trapping ultracold gases near cryogenic materials with rapid reconfigurability
We demonstrate a novel atom chip trapping system that allows the placement and high-resolution imaging of ultracold atoms within microns from any exchange with minimal experimental downtime. The sample is not connected to the atom chip, allowing rapid exchange without perturbing the atom chip or laser cooling apparatus. Exchange of the sample and retrapping of atoms has been performed within a week turnaround, limited only by chamber baking. Moreover, the decoupling of sample and atom chip provides the ability to independently tune the sample temperature and its position with respect to the trapped ultracold gas, which itself may remain in the focus of a high-resolution imaging system. As a first demonstration of this new system, we have confined a 700-nK cloud of 8x10^4 87Rb atoms within 100 um of a gold-mirrored 100-um-thick silicon substrate. The substrate was cooled to 35 K without use of a heat shield, while the atom chip, 120 um away, remained at room temperature. Atoms may be imaged and retrapped every 16 s, allowing rapid data collection.
Matthew A. Naides; Richard W. Turner; Ruby A. Lai; Jack M. DiSciacca; Benjamin L. Lev
Angular constraint on light-trapping absorption enhancement in solar cells
Light trapping for solar cells can reduce production cost and improve energy conversion efficiency. Understanding some of the basic theoretical constraints on light trapping is therefore of fundamental importance. Here, we develop a general angular constraint on the absorption enhancement in light trapping. We show that there is an upper limit for the angular integration of absorption enhancement factors. This limit is determined by the number of accessible resonances supported by an absorber.
Yu, Zongfu
Nano-texturization for Light Trapping in Crystalline Silicon Solar Cells
Abstract Scope, To address the question whether random or periodic nanostructures lead to better light trapping in solar cells, we design and fabricate three�...
Report of Flood, Oil Sheen, and fish Kill Incidents on East Fork Poplar Creek at the Oak Ridge Y-12 Plant
Water quality and plant opemtion irriiormation provided by the Y-12 Plant strongly suggest that a dechlorinating agent, applied to the raw water released below the North-South Pipes was responsible for the toxicity resulting in the fish kill of July 24. Dissolved oxygen (DO) measurements in upper EFPC indicai e that low oxygen levels (3-5 ppm) occurred for a period of up to 30 min. This slug of low DO water traveling down EFPC to the lake could easily explain the massive fish kill and the resulting observations. Dissolved oxygen levels of 5.2 ppm or lower are documented as causing problems for warmwater fish species (Heath 1995). The presence of other stressors, including a range of petrochemicals, tends to lower resistance to low oxygen conditions. Given the sequence of events in upper EFPC in the few days prior to July 24, where extremely high flows were followed by inputs of a wide range of low concentrations of oils, the sensitivity to low DO conditions might be heightened. The possible toxic impact of ::he oils and other contaminants reaching EFPC as a result of the heavy rainfidl on July 22 doesn't appear significant enough to be the sole cause of the kill on July 24. Even during the height of the kill, a large school of fish remained immediately downstream of the North-South Pipes. If the toxicity of waters flowing through this outlet were the primary cause of the kill, then it would be expected that this school of fish would not have been present immediately below the pipes. Any impact of waters entering from other sources, such as pumping of basements WOUIC1 have produced a staggered pattern of mortality, with fishing dying in different localities at different times and rates. Further, it would be expected that the morta.lhy observed would have continued over several days at least, as more resistant individuals succumbed slowly to the toxic exposure. This would have provided freshly dead or dying fish for the surveys of July 25 and 28. In previous fish kills in this stream section, the impact on the fish community has been judged to be short-term only, with no significant long-term ecological effects. In fact, the numerous fish kills over the past 7 years do not appear to have dampened the growth of the stream fish populations. The magnit~de of these kills was far less than that of the July 24 kill; maximum mortality of 10-20o/0 of th{~ total population above Lake Reality. Because the current kill has tiected a much larger proportion of the resident population, the impacts are expected to extend for a longer period in this situation, perhaps up to a year. Decreased population levels should be evident through the fhll 1997 and spring 1998 samples. Depending on the success rate of reproduction during the summer cf 1998, the recovery of fish populations should be observed in the fdl 1998 population sample. However, complete recovery may take several reproductive seasons to reach the densities seen in 1997. The cyprinid species occurring in upper EFPC have tremendous reproductive capacities and should be able to repopulate this area with little or no long-term ecological impact. Even the redbreast sunfish should, at the worst, only endure a narrowing of its available gene pool, with little if any long-term impacts.
Skaggs, B.E.
Steven Chu: Laser Cooling and Trapping of Atoms
Steven Chu Steven Chu Laser Cooling and Trapping of Atoms Resources with Additional Information · Interviews, Speeches, and Presentations · Patents Steven Chu Photo Credit: Lawrence Berkeley National Laboratory Roy Kaltschmidt, Photographer Steven Chu was appointed by President Barack Obama to be the 12th Secretary of Energy and served in this capacity until April 22, 2013. He was previously Director of Lawrence Berkeley National Laboratory (LBNL), Professor in the Physics Department at the University of California, Berkeley, and 'the Theodore and Frances Geballe Professor of Physics and Applied Physics at Stanford University. Professor Chu's research is in atomic physics, polymer and biophysics. His thesis and postdoctoral work at Berkeley ... was the observation of parity non-conservation in atomic transitions in 1978. This experiment was one of the earliest atomic physics confirmations of the Weinberg-Salam-Glashow theory that unifies the weak and electromagnetic forces.
Lean NOx Trap Catalysis for Lean Natural Gas Engine Applications
Distributed energy is an approach for meeting energy needs that has several advantages. Distributed energy improves energy security during natural disasters or terrorist actions, improves transmission grid reliability by reducing grid load, and enhances power quality through voltage support and reactive power. In addition, distributed energy can be efficient since transmission losses are minimized. One prime mover for distributed energy is the natural gas reciprocating engine generator set. Natural gas reciprocating engines are flexible and scalable solutions for many distributed energy needs. The engines can be run continuously or occasionally as peak demand requires, and their operation and maintenance is straightforward. Furthermore, system efficiencies can be maximized when natural gas reciprocating engines are combined with thermal energy recovery for cooling, heating, and power applications. Expansion of natural gas reciprocating engines for distributed energy is dependent on several factors, but two prominent factors are efficiency and emissions. Efficiencies must be high enough to enable low operating costs, and emissions must be low enough to permit significant operation hours, especially in non-attainment areas where emissions are stringently regulated. To address these issues the U.S. Department of Energy and the California Energy Commission launched research and development programs called Advanced Reciprocating Engine Systems (ARES) and Advanced Reciprocating Internal Combustion Engines (ARICE), respectively. Fuel efficiency and low emissions are two primary goals of these programs. The work presented here was funded by the ARES program and, thus, addresses the ARES 2010 goals of 50% thermal efficiency (fuel efficiency) and engines are being pursued. Approaches include: stoichiometric engine operation with exhaust gas recirculation and three-way catalysis, advanced combustion modes such as homogeneous charge compression ignition, and extension of the lean combustion limit with advanced ignition concepts and/or hydrogen mixing. The research presented here addresses the technical approach of combining efficient lean spark-ignited natural gas combustion with low emissions obtained from a lean NOx trap catalyst aftertreatment system. This approach can be applied to current lean engine technology or advanced lean engines that may result from related efforts in lean limit extension. Furthermore, the lean NOx trap technology has synergy with hydrogen-assisted lean limit extension since hydrogen is produced from natural gas during the lean NOx trap catalyst system process. The approach is also applicable to other lean engines such as diesel engines, natural gas turbines, and lean gasoline engines; other research activities have focused on those applications. Some commercialization of the technology has occurred for automotive applications (both diesel and lean gasoline engine vehicles) and natural gas turbines for stationary power. The research here specifically addresses barriers to commercialization of the technology for large lean natural gas reciprocating engines for stationary power. The report presented here is a comprehensive collection of research conducted by Oak Ridge National Laboratory (ORNL) on lean NOx trap catalysis for lean natural gas reciprocating engines. The research was performed in the Department of Energy's ARES program from 2003 to 2007 and covers several aspects of the technology. All studies were conducted at ORNL on a Cummins C8.3G+ natural gas engine chosen based on industry input to simulate large lean natural gas engines. Specific technical areas addressed by the research include: NOx reduction efficiency, partial oxidation and reforming chemistry, and the effects of sulfur poisons on the partial oxidation
Parks, II, James E [ORNL; Storey, John Morse [ORNL; Theiss, Timothy J [ORNL; Ponnusamy, Senthil [ORNL; Ferguson, Harley Douglas [ORNL; Williams, Aaron M [ORNL; Tassitano, James B [ORNL
Analysis of electron dynamics in non-ideal Penning traps
Penning traps that are used for particular applications, such as in ion pump technology, Larmor, bouncing, and diocotron frequencies, can be of the same order of magnitude. The paper deals with the dynamics of electrons confined in such devices starting from the study of the properties of the trajectories. In cases of interest, in which electron-neutral collision frequency is much smaller with respect to the characteristic frequencies of the motion, suitable time averages of the trajectories are introduced in order to simplify the analysis of the problem. In the work, time averages have been calculated in a simple way by using an approximate r-z decoupling of the effective potential. Results obtained with the method are presented and discussed in both linear and nonlinear regimes.
Coppa, G.; Mulas, R. [Dipartimento Energia, Politecnico di Torino, 10129 Torino (Italy); D'Angola, A. [Dipartimento di Ingegneria e Fisica dell'Ambiente, Universita della Basilicata, 85100 Potenza (Italy)
Distributed energy is an approach for meeting energy needs that has several advantages. Distributed energy improves energy security during natural disasters or terrorist actions, improves transmission grid reliability by reducing grid load, and enhances power quality through voltage support and reactive power. In addition, distributed energy can be efficient since transmission losses are minimized. One prime mover for distributed energy is the natural gas reciprocating engine generator set. Natural gas reciprocating engines are flexible and scalable solutions for many distributed energy needs. The engines can be run continuously or occasionally as peak demand requires, and their operation and maintenance is straightforward. Furthermore, system efficiencies can be maximized when natural gas reciprocating engines are combined with thermal energy recovery for cooling, heating, and power applications. Expansion of natural gas reciprocating engines for distributed energy is dependent on several factors, but two prominent factors are efficiency and emissions. Efficiencies must be high enough to enable low operating costs, and emissions must be low enough to permit significant operation hours, especially in non-attainment areas where emissions are stringently regulated. To address these issues the U.S. Department of Energy and the California Energy Commission launched research and development programs called Advanced Reciprocating Engine Systems (ARES) and Advanced Reciprocating Internal Combustion Engines (ARICE), respectively. Fuel efficiency and low emissions are two primary goals of these programs. The work presented here was funded by the ARES program and, thus, addresses the ARES 2010 goals of 50% thermal efficiency (fuel efficiency) and <0.1 g/bhp-hr emissions of oxides of nitrogen (NOx). A summary of the goals for the ARES program is given in Table 1-1. ARICE 2007 goals are 45% thermal efficiency and <0.015 g/bhp-hr NOx. Several approaches for improving the efficiency and emissions of natural gas reciprocating engines are being pursued. Approaches include: stoichiometric engine operation with exhaust gas recirculation and three-way catalysis, advanced combustion modes such as homogeneous charge compression ignition, and extension of the lean combustion limit with advanced ignition concepts and/or hydrogen mixing. The research presented here addresses the technical approach of combining efficient lean spark-ignited natural gas combustion with low emissions obtained from a lean NOx trap catalyst aftertreatment system. This approach can be applied to current lean engine technology or advanced lean engines that may result from related efforts in lean limit extension. Furthermore, the lean NOx trap technology has synergy with hydrogen-assisted lean limit extension since hydrogen is produced from natural gas during the lean NOx trap catalyst system process. The approach is also applicable to other lean engines such as diesel engines, natural gas turbines, and lean gasoline engines; other research activities have focused on those applications. Some commercialization of the technology has occurred for automotive applications (both diesel and lean gasoline engine vehicles) and natural gas turbines for stationary power. The research here specifically addresses barriers to commercialization of the technology for large lean natural gas reciprocating engines for stationary power. The report presented here is a comprehensive collection of research conducted by Oak Ridge National Laboratory (ORNL) on lean NOx trap catalysis for lean natural gas reciprocating engines. The research was performed in the Department of Energy's ARES program from 2003 to 2007 and covers several aspects of the technology. All studies were conducted at ORNL on a Cummins C8.3G+ natural gas engine chosen based on industry input to simulate large lean natural gas engines. Specific technical areas addressed by the research include: NOx reduction efficiency, partial oxidation and reforming chemistry, and the effects of sulfur poisons on the partial oxidation
Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration
Lean NOx Trap (LNT) catalysts can effectively reduce NOx from lean engine exhaust. Significant research for LNTs in diesel engine applications has been performed and has led to commercialization of the technology. For lean gasoline engine applications, advanced direct injection engines have led to a renewed interest in the potential for lean gasoline vehicles and, thereby, a renewed demand for lean NOx control. To understand the gasoline-based reductant chemistry during regeneration, a BMW lean gasoline vehicle has been studied on a chassis dynamometer. Exhaust samples were collected and analyzed for key reductant species such as H2, CO, NH3, and hydrocarbons during transient drive cycles. The relation of the reductant species to LNT performance will be discussed. Furthermore, the challenges of NOx storage in the lean gasoline application are reviewed.
Choi, Jae-Soon [ORNL; Prikhodko, Vitaly Y [ORNL; Partridge Jr, William P [ORNL; Parks, II, James E [ORNL; Norman, Kevin M [ORNL; Huff, Shean P [ORNL; Chambon, Paul H [ORNL; Thomas, John F [ORNL
Office of Scientific and Technical Information (OSTI)
Generation of continuous variable squeezing and entanglement of trapped ions in time-varying potentials
We investigate the generation of squeezing and entanglement for the motional degrees of freedom of ions in linear traps, confined by time-varying and oscillating potentials, comprised of a DC and an AC component. We show that high degrees of squeezing ... Keywords: 03.67.Bg, 05.45.Xt, 37.10.Vz, 42.50.Dv, Control, Entanglement, Ion traps
Alessio Serafini; Alex Retzker; Martin B. Plenio
Synoptic-Scale Structure and the Character of Coastally Trapped Wind Reversals
Coastally trapped wind reversals that occur along the U.S. West Coast have been described in numerous other studies. The synoptic-scale environment and the forcing of a coastally trapped Kelvin wave are highly linked in the development of these ...
Wendell A. Nuss
Charge trapping in ultrathin Gd2O3 high-k dielectric
Charge trapping in ultrathin high-k Gd"2O"3 dielectric leading to appearance of hysteresis in C-V curves is studied by capacitance-voltage and current-voltage techniques. It was shown that the large leakage current at a negative gate voltage causes the ... Keywords: Charge trapping, Gd2O3, High-k dielectric, Rare earth oxide
A. N. Nazarov; Y. V. Gomeniuk; Y. Y. Gomeniuk; H. D. B. Gottlob; M. Schmidt; M. C. Lemme; M. Czernohorsky; H. J. Osten
Physica Scripta. Vol. T22, 228-237, 1988. Summary of the Physics in Traps Panel
astrophysics, potential condensed matter experiments, and new ideas for optical and magnetic traps for neutral measured [7] their mass difference in a commercial spec- trometer (with cubic trap) to % 1 part in IO4dependence of the correction terms, one can clearly see the advantage of performing the experi- ment
California at San Diego, University of
Ion Trapping for Ion Mobility Spectrometry Measurements in a Cyclical Drift Tube
us to consider new types of mobility measurements. In traditional IMS instruments, R scales as (ELIon Trapping for Ion Mobility Spectrometry Measurements in a Cyclical Drift Tube Rebecca S. Glaskin 47405, United States ABSTRACT: A new ion trapping technique, involving the accumulation of ions
Clemmer, David E.
Loading of a surface-electrode ion trap from a remote, precooled source
We demonstrate loading of ions into a surface-electrode trap (SET) from a remote, laser-cooled source of neutral atoms. We first cool and load ?10[superscript 6] neutral [superscript 88]Sr atoms into a magneto-optical trap ...
Sage, Jeremy M.
A Novel Method for Fundamental Interaction Studies with Electrostatic Ion Beam Trap
Trapped radioactive atoms present exciting opportunities for the study of fundamental interactions and symmetries. For example, detecting beta decay in a trap can probe the minute experimental signal that originates from possible tensor or scalar terms in the weak interaction. Such scalar or tensor terms affect, e.g., the angular correlation between a neutrino and an electron in the beta-decay process, thus probing new physics of "beyond-the-standard-model" nature. In particular, this article focuses on a novel use of an innovative ion trapping device, the Electrostatic Ion Beam Trap (EIBT). Such a trap has not been previously considered for Fundamental Interaction studies and exhibits potentially very significant advantages over other schemes. These advantages include improved injection efficiency of the radionuclide under study, an extended field-free region, ion-beam kinematics for better efficiency and ease-of-operation and the potential for a much larger solid angle for the electron and recoiling atom counters.
S. Vaintraub; M. Hass; O. Aviv; O. Heber; I. Mardor
Hybrid particle traps and conditioning procedure for gas insulated transmission lines
A gas insulated transmission line includes an outer sheath, an inner condor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping ring is disposed within the outer sheath, and the trapping ring has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the trapping ring along an arc. A support sheet having an adhesive coating thereon is secured to the trapping ring and disposed on the outer sheath within the low field region formed between the trapping ring and the outer sheath. A conditioning method used to condition the transmission line prior to activation in service comprises applying an AC voltage to the inner conductor in a plurality of voltage-time steps, with the voltage-time steps increasing in voltage magnitude while decreasing in time duration.
Dale, Steinar J. (Monroeville, PA); Cookson, Alan H. (Churchill, PA)
Long-term drifts of stray electric fields in a Paul trap
We investigate the evolution of quasi-static stray electric fields in a linear Paul trap over a period of several months. Depending on how these electric fields are initially induced we observe very different time scales for the field drifts. Photo-induced electric fields decay on time scales of days. We interpret this as photo-electrically generated charges on insulating materials which decay via discharge currents. In contrast, stray fields due to the exposure of the ion trap to a beam of Ba atoms mainly exhibit slow dynamics on the order of months. We explain this observation as a consequence of a coating of the trap electrodes by the atomic beam. This may lead to contact potentials which can slowly drift over time due to atomic diffusion and chemical processes on the surface. In order not to perturb the field evolutions, we suppress the generation of additional charges and atomic coatings in the Paul trap during the measurements. For this, we shield the ion trap from ambient light and only allow the use of near-infrared lasers. Furthermore, we minimize the flux of atoms into the ion trap chamber. Long-term operation of our shielded trap led us to a regime of very low residual electric field drifts of less than 0.03 V/m per day.
Arne H�rter; Artjom Kr�kow; Andreas Brunner; Johannes Hecker Denschlag
We investigate the evolution of stray electric fields in a linear Paul trap over a period of several months. We demonstrate a way to clearly distinguish between the two main sources of these fields, namely insulated charged up patches and patch charges originating from contact potentials. To achieve high sensitivity in these measurements, we operate the trap in a way that strongly suppresses the generation of additional patch charges. For this, we shield the ion trap from ambient light and only allow the use of near-infrared lasers. Furthermore, we minimize additional contaminations of the trap electrodes by minimizing the flux of atoms into the ion trap chamber. We find that photo-induced electric fields decay on time scales of days. In contrast, stray fields due to contamination-induced contact potentials on trap electrodes mainly exhibit slow dynamics on the order of months, probably dominated by diffusion and slow chemical processes. Long-term operation of our shielded trap led us to a regime of very low ...
H�rter, Arne; Brunner, Andreas; Denschlag, Johannes Hecker
Bose-Einstein condensation in dark power-law laser traps
We investigate theoretically an original route to achieve Bose-Einstein condensation using dark power-law laser traps. We propose to create such traps with two crossing blue-detuned Laguerre-Gaussian optical beams. Controlling their azimuthal order l allows for the exploration of a multitude of power-law trapping situations in one, two, and three dimensions, ranging from the usual harmonic trap to an almost square-well potential, in which a quasihomogeneous Bose gas can be formed. The usual cigar-shaped and disk-shaped Bose-Einstein condensates obtained in a 1D or 2D harmonic trap take the generic form of a 'finger' or of a 'hockey puck' in such Laguerre-Gaussian traps. In addition, for a fixed atom number, higher transition temperatures are obtained in such configurations when compared with a harmonic trap of the same volume. This effect, which results in a substantial acceleration of the condensation dynamics, requires a better but still reasonable focusing of the Laguerre-Gaussian beams.
Jaouadi, A. [Universite Paris-Sud, Institut des Sciences Moleculaires d'Orsay (ISMO), F-91405 Orsay (France); CNRS, Orsay, F-91405 France (France); Laboratoire de Spectroscopie Atomique, Moleculaire et Applications (LSAMA), Department of Physics, Faculty of Science of Tunis, University of Tunis El Manar, T-2092 Tunis (Tunisia); Gaaloul, N. [Institut fuer Quantenoptik, Welfengarten 1, Gottfried Wilhelm Leibniz Universitaet, D-30167 Hannover (Germany); Viaris de Lesegno, B.; Pruvost, L. [CNRS, Laboratoire Aime Cotton (LAC), F-91405 Orsay (France); Universite Paris-Sud, Orsay, F-91405 France (France); Telmini, M. [Laboratoire de Spectroscopie Atomique, Moleculaire et Applications (LSAMA), Department of Physics, Faculty of Science of Tunis, University of Tunis El Manar, T-2092 Tunis (Tunisia); Charron, E. [Universite Paris-Sud, Institut des Sciences Moleculaires d'Orsay (ISMO), F-91405 Orsay (France); CNRS, Orsay, F-91405 (France)
Testing quantum physics in space using optically trapped nanospheres
Recent developments in space technology like micro-propulsion systems for drag-free control, thermal shielding, ultra-stable laser sources and stable optical cavities set an ideal platform for quantum optomechanical experiments with optically trapped dielectric spheres. Here, we will provide an overview of the results of recent studies aiming at the realization of the space mission MAQRO to test the foundations of quantum physics in a parameter regime orders of magnitude beyond existing experiments. In particular, we will discuss DECIDE, which is an experiment to prepare and then study a Schr\\"odinger-cat-type state, where a dielectric nanosphere of around 100nm radius is prepared in a superposition of being in two clearly distinct positions at the same time. This superposition leads to double-slit-type interference, and the visibility of the interference pattern will be compared to the predictions of quantum theory. This approach allows for testing for possible deviations from quantum theory as our test objects approach macroscopic dimensions. With DECIDE, it will be possible to distinctly test several prominent theoretical models that predict such deviations, for example: the Di\\'osi-Pensrose model, the continuous-spontaneous-localization model of Ghirardi, Rimini, Weber and Pearle, and the model of K\\'arolyh\\'azy.
Rainer Kaltenbaek
Dynamics of Methane Trapped in C(60) Interstices
In order to understand the hindered rotational and vibrational dynamics of methane trapped in C{sub 60} interstices and to determine the structure around the interstitial site, they have carried out inelastic neutron scattering studies of the methane/C{sub 60} system. At temperatures of 20K and below, they observe inelastic peaks from rotational transitions of the CH{sub 4}. These transitions allow unambiguous assignment of the hindered rotational energy levels and a determination of the interaction potential. The appearance of two peaks for one of the J = 0{r_arrow}3 transitions implies the existence of two distinct kinds of interstitial sites and the measured transition energies suggest a rotational barrier of about 26 and 16 meV for these sites. Time-dependent changes in peak heights indicate slow t{sub 1/2} ({approx} 2.6 hrs) triplet{r_arrow}quintet nuclear spin conversion that necessarily accompanies the J = 1{r_arrow}0 rotational relaxation. They also have observed a sharp inelastic peak at 9.3 meV, which corresponds to a local vibrational mode of CH{sub 4} rattling in its cage at {approximately} 2.2 THz. Other peaks involving higher-energy vibrational excitations in CD{sub 4}/C{sub 60} correspond in energy to assigned peaks in the inelastic neutron scattering spectra of C{sub 60}, albeit sometimes with different intensities.
Operation of the Lower Granite Dam Adult Trap, 2008.
During 2008 we operated the adult salmonid trap at Lower Granite Dam from 7 March through 25 November, except during a short summer period when water temperatures were too high to safely handle fish. We collected and handled a total of 20,463 steelhead Oncorhynchus mykiss and radio-tagged 34 of the hatchery steelhead. We took scale samples from 3,724 spring/summer Chinook salmon O. tshawytscha for age and genetic analysis. We collected and handled a total of 8,254 fall Chinook salmon. Of those fish, 2,520 adults and 942 jacks were transported to Lyons Ferry Hatchery on the Snake River in Washington. In addition, 961 adults and 107 jacks were transported to the Nez Perce Tribal Hatchery on the Clearwater River in Idaho. The remaining 3,724 fall Chinook salmon were passed upstream. Scales samples were taken from 780 fall Chinook salmon tagged with passive integrated transponder (PIT) tags and collected by the sort-by-code system.
Harmon, Jerrel R.
Certification Framework Based on Effective Trapping for Geologic Carbon Sequestration
We have developed a certification framework (CF) for certifying the safety and effectiveness of geologic carbon sequestration (GCS) sites. Safety and effectiveness are achieved if CO{sub 2} and displaced brine have no significant impact on humans, other living things, resources, or the environment. In the CF, we relate effective trapping to CO{sub 2} leakage risk which takes into account both the impact and probability of leakage. We achieve simplicity in the CF by using (1) wells and faults as the potential leakage pathways, (2) compartments to represent environmental resources that may be impacted by leakage, (3) CO{sub 2} fluxes and concentrations in the compartments as proxies for impact to vulnerable entities, (4) broad ranges of storage formation properties to generate a catalog of simulated plume movements, and (5) probabilities of intersection of the CO{sub 2} plume with the conduits and compartments. We demonstrate the approach on a hypothetical GCS site in a Texas Gulf Coast saline formation. Through its generality and flexibility, the CF can contribute to the assessment of risk of CO{sub 2} and brine leakage as part of the certification process for licensing and permitting of GCS sites around the world regardless of the specific regulations in place in any given country.
Oldenburg, Curtis M.; Bryant, Steven L.; Nicot, Jean-Philippe
Particle trap for compressed gas insulated transmission systems
A particle trap is provided for gas insulated transmission lines having a central high voltage conductor supported within an outer coaxial conductive sheath by a dielectric support member. A cavity between the inner conductor and outer sheath is filled with a dielectric insulating gas. A cone-like particle deflector, mounted to the inner conductor, deflects moving particles away from the support member, to radially outer portions of the cavity. A conductive shield is disposed adjacent the outer sheath to form a field-free region in radially outer portions of the cavity, between the shield and the sheath. Particles traveling along the cavity are deflected by the cone-like deflector into the field-free region where they are held immobile. In a vertical embodiment, particles enter the field-free region through an upper end of a gap formed between shield and sheath members. In a horizontal embodiment, the deflector cone has a base which is terminated radially internally of the shield. Apertures in the shield located adjacent the deflector allow passage of deflected particles into the field-free region. The dielectric support member is thereby protected from contaminating particles that may otherwise come to rest thereon.
Cookson, A.H.
Temperature-Driven Structural Phase Transition for Trapped Ions and a Proposal for its Experimental Detection
A Wigner crystal formed with trapped ions can undergo a structural phase transition, which is determined only by the mechanical conditions on a classical level. Instead of this classical result, we show that through consideration of quantum and thermal fluctuation, a structural phase transition can be driven solely by a change in the system's temperature. We determine a finite-temperature phase diagram for trapped ions using the renormalization group method and the path integral formalism, and propose an experimental scheme to observe the predicted temperature-driven structural phase transition, which is well within the reach of the current ion trap technology.
Gong Zhexuan; Lin, G.-D.; Duan, L.-M. [Department of Physics and MCTP, University of Michigan, Ann Arbor, Michigan 48109 (United States)
Method and apparatus for regenerating cold traps within liquid-metal systems
Oxide and hydride impurities of a liquid metal such as sodium are removed from a cold trap by heating to a temperature at which the metal hydroxide is stable in a molten state. The partial pressure of hydrogen within the system is measured to determine if excess hydride or oxide is present. Excess hydride is removed by venting hydrogen gas while excess oxide can be converted to molten hydroxide through the addition of hydrogen. The resulting, molten hydroxide is drained from the trap which is then returned to service at cold trap temperatures within the liquid-metal system.
McKee, Jr., John M. (Hinsdale, IL)
Radial transport of energetic ions in the presence of trapped electron mode turbulence
The nature of transport of hot ions is studied in the presence of microturbulence generated by the trapped electron mode in a Tokamak using massively parallel, first principle based global nonlinear gyrokinetic simulation, and with the help of a passive tracer method. Passing and trapped hot ions are observed to exhibit inverse and inverse square scaling with energy, while those with isotropic pitch distribution are found to exhibit inverse dependence on energy. For all types of hot ions, namely, isotropic, passing, and trapped, the radial transport appears to be subdiffusive for the parameters considered.
Chowdhury, J.; Wang, W.; Ethier, S.; Manickam, J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
Light Trapping for Thin Silicon Solar Cells by Femtosecond Laser Texturing: Preprint
Femtosecond laser texturing is used to create nano- to micron-scale surface roughness that strongly enhances light-trapping in thin crystalline silicon solar cells. Light trapping is crucial for thin solar cells where a single light-pass through the absorber is insufficient to capture the weakly absorbed red and near-infrared photons, especially with an indirect-gap semiconductor absorber layer such as crystalline Si which is less than 20 um thick. We achieve enhancement of the optical absorption from light-trapping that approaches the Yablonovitch limit.
Lee, B. G.; Lin, Y. T.; Sher, M. J.; Mazur, E.; Branz, H. M.
TRImP - A new facility to produce and trap radioactive isotopes
At the Kernfysisch Vensneller Institiutr (KVI) in Groningen, NL, a new facility (TRImP) is under development. It aims for producing, slowing down, and trapping of radioactive isotopes in order to perform accurate measurements on fundamental symmetries and interactions. A production target station and a dual magnetic separator installed and commissioned. We will slow down the isotopes of interest using an ion catcher and in a further stage a radiofrequency quadropole gas cooler (RFQ). The isotopes will finally be trapped in an atomic trap for precision studies.
Sohani, M
M. Sohani
History in the literary imagination: the telling of Nongqawuse and the Xhosa Cattle-Killing in South African literature and culture (1891-1937)
HISTORY IN THE LITERARY IMAGINATION: THE TELLING OF NONGQAWUSE AND THE XHOSA CATTLE-KILLING IN SOUTH AFRICAN LITERATURE AND CULTURE (1891�1937) SHEILA BONIFACE DAVIES ST JOHN�S COLLEGE A THESIS SUBMITTED... and bully this dissertation into being. For wittingly, or unwittingly, contributing in a myriad different ways, I would like to thank: Anonymous readers; Anne Torlesse, Cecilia Blight, Crystal Warren and Lynne Grant (National English Library Museum...
Boniface Davies, Sheila
Investigation of Aging Mechanisms in Lean NOx Traps
Lean NO{sub x} traps (LNTs) represent a promising technology for the abatement of NO{sub x} under lean conditions. Although LNTs are starting to find commercial application, the issue of catalyst durability remains problematic. LNT susceptibility to sulfur poisoning is the single most important factor determining effective catalyst lifetime. The NO{sub x} storage element of the catalyst has a greater affinity for SO{sub 3} than it does for NO{sub 2}, and the resulting sulfate is more stable than the stored nitrate. Although this sulfate can be removed from the catalyst by means of high temperature treatment under rich conditions, the required conditions give rise to deactivation mechanisms such as precious metal sintering, total surface area loss, and solid state reactions between the various oxides present. The principle objective of this project was to improve understanding of the mechanisms of lean NO{sub x} trap aging, and to understand the effect of washcoat composition on catalyst aging characteristics. The approach utilized involved detailed characterization of model catalysts prior to and after aging, in tandem with measurement of catalyst performance in NO{sub x} storage and reduction. In this manner, NO{sub x} storage and reduction characteristics were correlated with the evolution of catalyst physico-chemical properties upon aging. Rather than using poorly characterized proprietary catalysts, or simple model catalysts of the Pt/BaO/Al{sub 2}O{sub 3} type (representing the first generation of LNTs), Pt/Rh/BaO/Al{sub 2}O{sub 3} catalysts were employed which also incorporated CeO{sub 2} or CeO{sub 2}-ZrO{sub 2}, representing a model system which more accurately reflects current LNT formulations. Catalysts were prepared in which the concentration of each of the main components was systematically varied: Pt (50, 75 or 100 g/ft{sup 3}), Rh (10 or 20 g/ft{sup 3}), BaO (15, 30 or 45 g/L), and either CeO{sub 2} (0, 50 or 100 g/L) or CeO{sub 2}-ZrO{sub 2} (0, 50 or 100 g/L). A high surface area La-stabilized alumina was used to support the BaO phase. Catalysts were obtained by washcoating onto standard cordierite substrates, the total washcoat loading being set at 260 g/L. La-stabilized alumina was used as the balance. Subsequent to de-greening, the NO{sub x} storage and reduction characteristics of the catalysts were evaluated on a bench reactor, after which the catalysts were aged on a bench reactor to the equivalent of ca. 75,000 miles of road aging using a published accelerated aging protocol. The aged catalysts were then subjected to the same evaluation proecdure used for the de-greened catalysts. In addition to the use of standard physico-chemical analytical techniques for studying the fresh and aged model catalysts, use was made of advanced analytical tools for characterizing their NO{sub x} storage/reduction and sulfation/desulfation characteristics, such as Spatially resolved capillary-inlet Mass Spectrometry (SpaciMS) and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS).
Mark Crocker
Lean NOx Trap Modeling in Vehicle Systems Simulations
A one-dimensional model for simulating lean NOx trap (LNT) performance is developed and validated using both steady state cycling data and transient data from FTP testing cycles. The model consists of the conservation equations for chemical species and energy in the bulk flow, energy of the solid walls, O2 storage and NOx storage (in the form of nitrites and nitrates). Nitrites and nitrates are formed by diffusion of NO and NO2, respectively, into sorbent particles (assumed to be hemi-spherical in shape) along with O2 and their formation rates are controlled by chemical kinetics as well as solid-phase diffusion rates of NOx species. The model also accounts for thermal aging and sulfation of LNTs. Empirical correlations are developed on the basis of published experimental data to capture these effects. These empirical correlations depend on total mileage for which the LNT has been in use, the mileage accumulated since the last desulfation event in addition to the freshly degreened catalyst characteristics. The model has been used in studies of vehicle systems (integration, performance etc.) including hybrid powertrain configurations. Since the engines in hybrid vehicles turn on and off multiple number of times during single drive cycles, the exhaust systems may encounter multiple cold start transients. Accurate modeling of catalyst warm-up and cooling is, therefore, very important to simulate LNT performance in such vehicles. For this purpose, the convective heat loss from the LNT to the ambient is modeled using a Nusselt number correlation that includes effects of both forced convection and natural convection (with later being important when vehicle is stationary). Using the model, the fuel penalty associated with operating LNTs on small diesel engine powered car during FTP drive cycles is estimated.
Gao, Zhiming [ORNL; Chakravarthy, Veerathu K [ORNL; Daw, C Stuart [ORNL; Conklin, Jim [ORNL
Temperature, acetosyringone, virulence genes and wounding effects on Agrobacterium-mediated transformation efficiency
Several conditions were evaluated to determine their impact on Agrobacterium-mediated transformation efficiency. Temperature and acetosyringone (AS) effects were first studied in tobacco, as a plant model system and then applied to cotton transformation. In tobacco, AS significantly increased transformation rates that resulted in stable transformed plants. Four temperatures were evaluated during the cc-cultivation period to determine the most appropriate temperature for T-DNA transfer and integration into the plant genome. Even though 19�C was reported in the literature as the optimal temperature for Agrobacterium-mediated gene transfer, 25�C was statistically significantly different as compared to 15�C, 19�C or 32�C and produced the highest number of transgenic tobacco plants. The superior treatments established in tobacco transformation were applied to Agrobacterium-mediated transformation of the cotton shoot apex. Explant survival rates in selection medium were recorded and used to compare two temperatures (19�C and 25�C) and the effects of AS to induce the vir genes. After approximately 6-7 wk in selection medium, the percentage of surviving exhalants established that 25�C was the best temperature for cotton transformation, either with or without AS. Two wounding methods and the addition of a super-virulent plasmid were tested in cotton shoot apex transformation experiments. Their effects were evaluated using the green fluorescent protein (GFP) as an in vivo reporter gene to determine the early transformation patterns. Both removal of a leaf primordial and sanitation were examined. Transient GFP expression did not reveal any major benefit of the treatments on the transformation pattern. In contrast, when additional copies of virG and virE genes were inserted into Agrobacterium, a considerable increase in the number of fluorescence spots per exploit was evident. This was the first time GFP gene was used in cotton. Its expression was reliable, and the system was successfully established. Since GFP has several advantages as a reporter gene over the traditional GUS gene and herbicide resistance genes, it would allow the development of a more accurate selection process and therefore it would speed up the optimization of the shoot apex method.
Salas Fernandez, Maria Guadalupe
Bear Trap Hot Spring Pool & Spa Low Temperature Geothermal Facility | Open
Trap Hot Spring Pool & Spa Low Temperature Geothermal Facility Trap Hot Spring Pool & Spa Low Temperature Geothermal Facility Jump to: navigation, search Name Bear Trap Hot Spring Pool & Spa Low Temperature Geothermal Facility Facility Bear Trap Hot Spring Sector Geothermal energy Type Pool and Spa Location Norris, Montana Coordinates 45.5679836°, -111.690808° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[]}
Atom Trap Trace Analysis at ANL | U.S. DOE Office of Science (SC)
Office of Science (SC) Website
Atom Trap Trace Analysis at ANL Atom Trap Trace Analysis at ANL Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: email@example.com More Information » Spinoff Archives Atom Trap Trace Analysis at ANL Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Atom Trap Trace Analysis (ATTA) to determine isotopic abundances. Developed at: Argonne National Laboratory Developed in: 1999-current
Triplet Transport to and Trapping by Acceptor End Groups on Conjugated
Triplet Transport to and Trapping by Acceptor End Groups on Conjugated Triplet Transport to and Trapping by Acceptor End Groups on Conjugated Polyfluorene Chains Paiboon Sreearunothai, Alexis Estrada, Sadayuki Asaoka, Marta Kowalczyk, Seogjoo Jang, Andrew R. Cook, Jack M. Preses and John R. Miller J. Phys. Chem. C 115, 19569-19577 (2011). [Find paper at ACS Publications] Abstract: Triplet excited states created in polyfluorene (pF) molecules having average lengths up to 170 repeat units were transported to and captured by trap groups at the ends in less ~40 ns. Almost all of the triplets attached to the chains reached the trap groups, ruling out the presence of substantial numbers of defects that prevent transport. The transport yields a diffusion coefficient D of at least 3 x 10-4 cm2 s-1, which is 30 times typical molecular diffusion and close to a value for triplet transport
Integrated photonic structures for light trapping in thin-film Si solar cells
We explore the mechanisms for an efficient light trapping structure for thin-film silicon solar cells. The design combines a distributed Bragg reflector (DBR) and periodic gratings. Using photonic band theories and numerical ...
Scattering of Coastal-Trapped Waves by Irregularities in Coastline and Topography
The scattering of freely-propapting coastal-trapped waves (CTWs) by large variations in coastline and topography is studied using a numerical model which accomodates arbitrary density stratification, bathymetry and coastline. Particular attention ...
John L. Wilkin; David C. Chapman
On the application of radio frequency voltages to ion traps via helical resonators
Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.
Siverns, J D; Weidt, S; Hensinger, W K
The Scattering of Long Coastal-Trapped Waves in Frictional Seas
The scattering of coastal-trapped waves (CTWs) by a region of irregular shelf bathymetry is determined from a circulation integral of the depth-integrated momentum equations. For relatively weak stratification the conservation of geostrophic mass ...
John F. Middleton; Mark A. Merrifield
Light trapping in thin film solar cells using textured photonic crystal
A solar cell includes a photoactive region that receives light. A photonic crystal is coupled to the photoactive region, wherein the photonic crystal comprises a distributed Bragg reflector (DBR) for trapping the light.
Yi, Yasha (Somerville, MA); Kimerling, Lionel C. (Concord, MA); Duan, Xiaoman (Amesbury, MA); Zeng, Lirong (Cambridge, MA)
Simple Models of Coastal-Trapped Waves Based on the Shape of the Bottom Topography
Solutions of barotropic coastal-trapped waves in the shallow-water context are discussed for different shapes of the bottom topography. In particular, an infinite family of topographic waves over continental shelves characterized by a shape ...
L. Zavala Sans�n
An optical-fiber interface to a trapped-ion quantum computer
The trapped-ion quantum computer is an atom-based implementation of a quantum computer that has successfully demonstrated numerous quantum algorithms and the potential for scalability. Fundamental to its operation is the ...
Kim, Tony Hyun
Synoptic Forcing Of Coastal-Trapped Disturbances in the Marine Atmospheric Boundary Layer
Motivated by recent observations along the west coast of the United States, the authors investigate the generation and propagation of coastal-trapped disturbances in the marine atmospheric boundary layer. Analytic solutions are obtained in a ...
A. M. Rogerson; R. M. Samelson
Sensitivity of Coastally Trapped Disturbance Dynamics to Barrier Height and Topographic Variability in a Numerical Model
The sensitivity of a coastally trapped disturbance (CTD) to topographic height is examined using simulations of the 15�18 May 1985 CTD. These simulations include three with uniform topography, in which the North American west coast mountains are ...
K. J. Tory; P. L. Jackson; C. J. C. Reason
Scattering of Coastally Trapped Waves by Changes in Continental Shelf Width
The scattering of dispersive, barotropic, coastally-trapped waves by narrowing and widening shelves is investigated. The shelves considered maintain a shelf-similar exponential shape. For such shelves, previous investigators have shown that no ...
Ian Webster
Technological assessment of light-trapping technology for thin-film Si solar cell
The proposed light trapping technology of Distributed Bragg Reflector (DBR) with Diffraction Grating (DG) and Anti-Reflection Coating (ARC) for thin film Si solar cell was analyzed from the technology, market, and ...
Susantyoko, Rahmat Agung
Depletion, quantum jumps, and temperature measurements of ??Sr? ions in a linear Paul Trap
This thesis describes the design and construction of two laser systems to probe the 674nm transition of ??Sr? ions in a linear Paul trap. The first laser system made use of a molecular transition in Iodine to stabilize the ...
Richerme, Philip J
A Comparison of Long Coastal Trapped Wave Theory with Observations off Peru
The agreement between coastal trapped wave theory and observation is studied for the case of observations made off Peru during the 1977 CUEA JOINT-II experiment. Wave properties are calculated using a numerical model with realistic, horizontally ...
Direct Calculation of Low-Frequency Coastally Trapped Waves and Their Scattering
A new, direct numerical method is proposed for finding the phase speeds and pressure fields of low-frequency nondispersive coastally trapped waves in a continuously stratified flow. The usual two-dimensional problem is reduced to a one-...
G. A. Schmidt; E. R. Johnson
A Modeling Study of Nonstationary Trapped Mountain Lee Waves. Part II: Nonlinearity
The generation of nonstationary trapped mountain lee waves through nonlinear wave dynamics without any concomitant change in the background flow is investigated by conducting two-dimensional mountain wave simulations. These simulations ...
Louisa B. Nance; Dale R. Durran
Effects of trap anisotropy on impurity scattering regime in a Fermi gas
We evaluate the low-lying oscillation modes and the ballistic expansion properties of a harmonically trapped gas of fermionic K40 atoms containing thermal Rb87 impurities as functions of the anisotropy of the trap. Numerical results are obtained by solving the Vlasov-Landau equations for the one-body phase-space distribution functions and are used to test simple scaling Ansatzes. Starting from the gas in a weak impurity-scattering regime inside a spherical trap, the time scales associated to motions in the axial and azimuthal directions enter into competition as the trap is deformed to an elongated cigar-like shape. This competition gives rise to coexistence of collisionless and hydrodynamic behaviors in the low-lying surface modes of the gas as well as to a dependence of the aspect ratio of the expanding cloud on the collision time.
P. Capuzzi; P. Vignolo; M. P. Tosi
J. D. Siverns; L. R. Simkins; S. Weidt; W. K. Hensinger
Ancient Lava Flows Trap CO2 for Long-Term Storage in Big Sky...
3, 2013 Ancient Lava Flows Trap CO2 for Long-Term Storage in Big Sky Injection Photo by J.D. Griggs, courtesy of U.S.Geological Survey Photo by J.D. Griggs, courtesy of...
An injection-locked 674 nm laser for Strontium-88 ion trapping
Energy levels of the valence electron of a single trapped ??Sr+ ion can be harnessed as an effective qubit for quantum information processing. The qubit transition to a metastable energy state can be stimulated by a laser ...
Katz, Rena J. (Rena Jenelle)
Coastal-Trapped Waves off the Coast of South Africa: Generation, Propagation and Current Structures
Coastal sea level variations from six sites around South Africa are used to establish the characteristics of coastal-trapped wave (CTW) propagation. Substantial amplitudes (>50 cm) are found along the south coast, but further propagation on the ...
E. H. Schumann; K. H. Brink
Engineering optical traps for new environments and applications in the measurement of biological adhesives and motors
Optical traps have played a central role in the exploration of biological systems through the examination of molecular motors, biopolymers, and many other interactions at the nano and micro length scales. This thesis seeks ...
Appleyard, David Collins
The Energy Source for the Coastal-Trapped Waves in the Australian Coastal Experiment Region
The sea level on the southern Australian coast is examined for the source of the coastal-trapped wave energy observed during the Australian Coastal Experiment. Sea level, adjusted for atmospheric pressure, and atmospheric pressure are observed to ...
John A. Church; Howard J. Freeland
Cessation of the 22�25 June 2006 Coastally Trapped Wind Reversal
Coastally trapped wind reversals (CTWRs) occur periodically in the marine boundary layer off the western coast of the United States and dramatically change the low-level wind regime and coastal weather. Southerly flow becomes established with the ...
David A. Rahn; Thomas R. Parish
Sea Surface Mixed Layer during the 10�11 June 1994 California Coastally Trapped Event
A midlevel, coastally trapped atmospheric event occurred along the California coast 10�11 June 1994. This feature reversed the surface wind field along the coast in a northerly phase progression. Along the central California coast, the winds at ...
C. E. Dorman; L. Armi; J. M. Bane; D. P. Rogers
Molecular dynamics simulation of deuterium trapping and bubble formation in tungsten
Molecular dynamics simulation of deuterium trapping and bubble formation in tungsten Xue Yang using classical molecular dynamic methods. " Low energy deuterium atoms tend to affix to high environment. The deuterium bombardment of monocrystalline tungsten was modeled by molecular dynamics
Harilal, S. S.
Phenomenon of parametric trapping of electromagnetic waves in an inhomogeneous plasma
A theory is developed of absolute parametric aperiodic instability in a spatially inhomogeneous plasma, when the electromagnetic waves generated in the plasma are trapped by the plasma near the peaks of the pumping-wave field.
Silin, V.P.; Starodub, A.N.
A Systematic Search for Trapped Equatorial Waves in the GATE Velocity Data
Moored current meter data taken over a 60-day period during GATE (GARP Atlantic Tropical Experiment) near the equator at 28�W, have been systematically searched for vertically propagating equatorially trapped waves. Three independent tests ...
A. M. Horigan; R. H. Weisberg
Numerical Simulation of Flow around a Tall Isolated Seamount. Part II: Resonant Generation of Trapped Waves
A sigma-coordinate, primitive equation ocean circulation model is used to explore the problem of the remnant generation of trapped waves about a tall, circular, isolated seamount by an incident oscillatory barotropic current. The numerical ...
Dale B. Haidvogel; Aike Beckmann; David C. Chapman; Ray-Qing Lin
Additional Steam Traps Increase Production of a Drum Oven at a Petroleum Jelly Plant
Additional steam traps were installed on the drum oven at a petroleum jelly production facility at an ExxonMobil plant in Nigeria. The installation improved heat transfer and saved energy.
Mesoscale Eddy Formation and Shock Features Associated with a Coastally Trapped Disturbance
On 28 August 2002, a visually striking sequence of events appeared in satellite imagery showing a coastally trapped disturbance (CTD) propagating northward along the coast of California against a northerly background flow. As a narrow tongue of ...
Stephen D. Burk; William T. Thompson
Vertically aligned gas-insulated transmission line having particle traps at the inner conductor
Gas insulated electrical apparatus having first and second conductors separated by an insulating support within an insulating gas environment, and particle traps disposed along the surface of the high potential conductor for trapping and inactivating foreign particles which may be present within the insulating gas medium. Several embodiments of the invention were developed which are particularly suited for vertically aligned gas insulated transmission lines. The particle traps are grooves or cavities formed into the walls of the tubular inner conductor, without extending into the hollow portion of the conductor. In other embodiments, the traps are appendages or insert flanges extending from the inner conductor, with the insulator supports contacting the appendages instead of the inner conductor.
Dale, Steinar J. (Monroeville, PA)
An imaging co-axial tube electrodynamic trap for manipulation of charged particles
A tubular particle trapping device was designed and fabricated using two co-axial electrically conductive tubes with diameters of 5 mm and 7 mm, respectively. The device was integrated with an imaging camera and optical fiber bundle for real time monitoring of trapped particle motion. Charged microparticles of 3 to 50 m diameter can be suspended in air at ambient pressure using the device utilizing a quadrupole potential with an alternating voltage of amplitude 300 V to 750 V and frequency of 30 Hz to 140 Hz. Controlled trapping of a single particle or multiple particles can be achieved by tuning the voltage amplitude. The particle remained trapped when the entire assembly was translated or rotated. The device can be used as a manipulator for charged particle transport and repositioning.
Jiang, Ms. Linan [University of Arizona; Whitten, William B [ORNL; Pau, Dr. Stanley [University of Arizona/Bell Labs
Dipole traps for neutral atoms formed by nonuniformly polarised Laguerre modes
Field configurations of two counterpropagating nonuniformly polarised Laguerre modes forming three-dimensional dipole traps for neutral atoms are proposed. Peculiarities of the stochastic dynamics of atoms in such traps, associated with the anisotropy of dipole forces and manifestations of various radiative friction mechanisms are analysed. The problem of increasing the confinement time for atoms in such field configurations is studied. (laser applications and other topics in quantum electronics)
Bezverbny, Aleksandr V [Maritime State University, Vladivostok (Russian Federation); Niz'ev, Vladimir G [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation); Tumaikin, Anatolii M [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)
Trapping of quantum particles and light beams by switchable potential wells
We consider basic dynamical effects in settings based on a pair of local potential traps that may be effectively switched on and off, or suddenly displaced, by means of appropriate control mechanisms, such as the scanning tunneling microscopy (STM) or photo-switchable quantum dots. The same models, based on the linear Schrodinger equation with time-dependent trapping potentials, apply to the description of optical planar systems designed for the switching of trapped light beams. The analysis is carried out in the analytical form, using exact solutions of the Schrodinger equation. The first dynamical problem considered in this work is the retention of a particle released from a trap which was suddenly turned off, while another local trap was switched on at a distance - immediately or with a delay. In this case, we demonstrate that the maximum of the retention rate is achieved at a specific finite value of the strength of the new trap, and at a finite value of the temporal delay, depending on the distance between the two traps. Another ptoblem is retrapping of the bound particle when the addition of the second trap transforms the single-well setting into a double-well potential (DWP). In that case, we find probabilities for the retrapping into the ground or first excited state of the DWP. We also analyze effects entailed by the application of a kick to a bound particle, the most interesting one being a kick-induced transition between the DWP's ground and excited states. In the latter case, the largest transition probability is achieved at particular strength of the kick.
Eduard Sonkin; Boris A. Malomed; Er'el Granot; Avi Marchewka
Trapping of Implanted He at Cu/Nb Interfaces Measured by Neutron Reflectometry
In single crystalline metals, He is insoluble and precipitates into bubbles. In contrast, Cu-Nb multilayers show no evidence of bubble formation below a critical concentration. The conclusions of this paper are: (1) He is trapped at Cu/Nb , Cu/Mo interfaces; (2) He is trapped interstitially; (3) The interface swells {approx} 10 times; and (4) The layered structure retains despite the swell of interfaces.
Wang, Peng [Los Alamos National Laboratory; Zhernenkov, Mikhail [Applications Scientist at Nanometrics; Kashinath, Abishek [MIT; Demkowicz, Michael [MIT; Baldwin, Jon K. [Los Alamos National Laboratory; Majewski, Jaroslaw [Los Alamos National Laboratory
Grooved impactor and inertial trap for sampling inhalable particulate matter. [Patents
An inertial trap and grooved impactor for providing a sharp cutoff for particles over 15 microns from entering an inhalable particulate sampler is disclosed. The impactor head has a tapered surface and is provided with V-shaped grooves. The tapered surface functions for reducing particle blow-off or reentrainment while the grooves prevent particle bounce. Water droplets and any resuspended material over the 15 micron size are collected by the inertial trap and deposited in a reservoir associated with the impactor.
Loo, B.W.
Immobilization of Cesium Traps from the BN-350 Fast Reactor (Aktau, Kazakhstan)
During BN-350 reactor operations and also during the initial stages of decommissioning, cesium traps were used to decontaminate the reactor�s primary sodium coolant. Two different types of carbon-based trap were used � the MAVR series, low ash granulated graphite adsorber (LAG) contained in a carrier designed to be inserted into the reactor core during shutdown; and a series of ex-reactor trap accumulators(TAs) which used reticulated vitreous carbon (RVC) to reduce Cs-137 levels in the sodium after final reactor shutdown. In total four MAVRs and seven TAs were used at BN-350 to remove an estimated cumulative 755 TBq of cesium. The traps, which also contain residual sodium, need to be immobilized in an appropriate way to allow them to be consigned as waste packages for long term storage and, ultimately, disposal. The present paper reports on the current status of the implementation phase, with particular reference to the work done to date on the trap accumulators, which have the most similarity with the cesium traps used at other reactors.
J. A. Michelbacher; C. Knight; O. G. Romanenko; I. L. Tazhibaeva; I. L. Yakovlev; A. V. Rovneyko; V. I. Maev; D. Wells; A. Herrick
Transport of ions in a segmented linear Paul trap in printed-circuit-board technology
We describe the construction and operation of a segmented linear Paul trap, fabricated in printed-circuit-board technology with an electrode segment width of 500 microns. We prove the applicability of this technology to reliable ion trapping and report the observation of Doppler cooled ion crystals of Ca-40 with this kind of traps. Measured trap frequencies agree with numerical simulations at the level of a few percent from which we infer a high fabrication accuracy of the segmented trap. To demonstrate its usefulness and versatility for trapped ion experiments we study the fast transport of a single ion. Our experimental results show a success rate of 99.0(1)% for a transport distance of 2x2mm in a round-trip time of T=20us, which corresponds to 4 axial oscillations only. We theoretically and experimentally investigate the excitation of oscillations caused by fast ion transports with error-function voltage ramps: For a slightly slower transport (a round-trip shuttle within T=30us) we observe non-adiabatic motional excitation of 0.89(15)meV.
G. Huber; T. Deuschle; W. Schnitzler; R. Reichle; K. Singer; F. Schmidt-Kaler
Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by >90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as "regeneration" since the catalyst is reactivated for more NOx trapping after NOx purge. Creating the rich exhaust conditions for regeneration can be accomplished by catalytic partial oxidation of methane in the exhaust system. Furthermore, catalytic reforming of partial oxidation exhaust can enable increased quantities of H2 which is an excellent reductant for lean NOx trap regeneration. It is critical to maintain clean and efficient partial oxidation and reforming processes to keep the lean NOx trap functioning properly and to reduce extra fuel consumption from the regeneration process. Although most exhaust constituents do not impede partial oxidation and reforming, some exhaust constituents may negatively affect the catalysts and result in loss of catalytic efficiency. Of particular concern are common catalyst poisons sulfur, zinc, and phosphorous. These poisons form in the exhaust through combustion of fuel and oil, and although they are present at low concentrations, they can accumulate to significant levels over the life of an engine system. In the work presented here, the effects of sulfur on the partial oxidation and reforming catalytic processes were studied to determine any durability limitations on the production of reductants for lean NOx trap catalyst regeneration.
Parks, II, James E [ORNL; Ponnusamy, Senthil [ORNL
Development of Metal Substrate for Denox Catalysts and Particulate Trap
The objective of this project was to develop advanced metallic catalyst substrate materials and designs for use in off-highway applications. The new materials and designs will be used as catalyst substrates and diesel particulate traps. They will increase durability, reduce flow resistance, decrease time to light-off, and reduce cost relative to cordierite substrates. Metallic catalyst substrates are used extensively for diesel oxidation catalysts and have the potential to be used in other catalytic systems for diesel engines. Metallic substrates have many advantages over ceramic materials including improved durability and resistance to thermal shock and vibration. However, the cost is generally higher than cordierite. The most common foil material used for metallic substrates is FeCr Alloy, which is expensive and has temperature capabilities beyond what is necessary for diesel applications. The first task in the project was Identification and Testing of New Materials. In this task, several materials were analyzed to determine if a low cost substitute for FeCr Alloy was available or could be developed. Two materials were identified as having lower cost while showing no decrease in mechanical properties or oxidation resistance at the application temperatures. Also, the ability to fabricate these materials into a finished substrate was not compromised, and the ability to washcoat these materials was satisfactory. Therefore, both candidate materials were recommended for cost savings depending on which would be less expensive in production quantities. The second task dealt with the use of novel flow designs to improve the converter efficiency while possibly decreasing the size of the converter to reduce cost even more. A non-linear flow path was simulated to determine if there would be an increase in efficiency. From there, small samples were produced for bench testing. Bench tests showed that the use of non-linear channels significantly reduced the light-off temperature for diesel oxidation catalytic converters. Finally, the third task was to implement these materials and designs into a full-size converter. Hot shake testing of 13-inch diameter straight channel substrates showed no significant difference in durability between the current material and the two proposed materials. At the time that this program ended, preparations were being made for full-scale emissions testing of the new design converter for comparison to a traditional straight channel with equal catalyst loading.
Pollard, Michael; Habeger, Craig; Frary, Megan; Haines, Scott; Fluharty, Amy; Dakhoul, Youssef; Carr, Michael; Park, Paul; Stefanick, Matthew; DaCosta, Herbert; Balmer-Millar, M Lou; Readey, Michael; McCluskey, Philip
Linear trap with three orthogonal quadrupole fields for dust charging experiments
Investigations of charging processes on a single dust grain under controlled conditions in laboratory experiments are the unique way to understand the behavior of dust grains in complex plasma (in space, in laboratory, or in technological applications). An electrodynamic trap is often utilized for both holding a single grain and continuously measuring its charge-to-mass ratio. We propose a modified design of the linear quadrupole trap with the electrodes split into two parts; each of them being supplied by a designated source. The paper presents basic calculations and the results of the trap prototype tests. These tests have confirmed our expectations and have shown that the suggested solution is fully applicable for the dust charging experiments. The uncertainty of determination of the dust grain charge does not exceed 10{sup -3}. The main advantages of the suggested design in comparison with other traps used for dust investigations can be summarized as: The trap (i) is more opened, thus it is suitable for a simultaneous application of the ion and electron beams and UV source; (ii) facilitates investigations of dust grains in a broader range of parameters; and (iii) allows the grain to move along the axis in a controlled way.
Beranek, Martin; Nemecek, Zdenek; Safrankova, Jana; Jerab, Martin; Pavlu, Jiri [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Cermak, Ivo [CGC Instruments, Chemnitz (Germany)
The uses of electron beam ion traps in the study of highly charged ions
The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.
Knapp, D.
Particle trap to sheath contact for a gas-insulated transmission line having a corrugated outer conductor
A particle trap to outer elongated conductor or sheath contact for gas-insulated transmission lines. The particle trap to outer sheath contact of the invention is applicable to gas-insulated transmission lines having either corrugated or non-corrugated outer sheaths. The contact of the invention includes an electrical contact disposed on a lever arm which in turn is rotatably disposed on the particle trap and biased in a direction to maintain contact between the electrical contact and the outer sheath.
Fischer, William H. (Pittsburgh, PA); Cookson, Alan H. (Pittsburgh, PA); Yoon, Kue H. (Pittsburgh, PA)
Particle trap to sheath non-binding contact for a gas-insulated transmission line having a corrugated outer conductor
A non-binding particle trap to outer sheath contact for use in gas insulated transmission lines having a corrugated outer conductor. The non-binding feature of the contact according to the teachings of the invention is accomplished by having a lever arm rotatably attached to a particle trap by a pivot support axis disposed parallel to the direction of travel of the inner conductor/insulator/particle trap assembly.
Fischer, William H. (Pittsburgh, PA)
The on-line charge breeding program at TRIUMF's Ion Trap For Atomic and Nuclear Science for precision mass measurements
TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) constitutes the only high precision mass measurement setup coupled to a rare isotope facility capable of increasing the charge state of short-lived nuclides prior to the actual mass determination in a Penning trap. Recent developments around TITAN's charge breeder, the electron beam ion trap, form the basis for several successful experiments on radioactive isotopes with half-lives as low as 65 ms and in charge states as high as 22+.
Simon, M. C.; Eberhardt, B.; Jang, F.; Luichtl, M.; Robertson, D.; Chaudhuri, A.; Delheij, P.; Grossheim, A.; Kwiatkowski, A. A.; Mane, E.; Pearson, M. R.; Schultz, B. E. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Bale, J. C. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Chowdhury, U. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Ettenauer, S.; Gallant, A. T.; Dilling, J. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada); Lennarz, A. [TRIUMF, Vancouver, British Columbia V6T 2A3 (Canada); Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet, D-48149 Muenster (Germany); Ma, T.; Andreoiu, C. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); and others
Electron and hole transport to trap groups at the ends of conjugated
and hole transport to trap groups at the ends of conjugated and hole transport to trap groups at the ends of conjugated polyfluorenes Sadayuki Asaoka, Norihiko Takeda, Tornokazu Lyoda, Andrew R. Cook and John R. Miller J. Am. Chem. Soc. 130, 11912-11920 (2008). [Find paper at ACS Publications] Abstract: Electrons and holes were injected selectively into poly-2,7-(9,9-dihexylfluorene) (pF) dissolved in a tetrahydrofuran (THF) and a 1,2-dichloroethane (DCE) solution, respectively, using pulse radiolysis. Transient absorption spectra of monoions of both signs revealed two bands attributable to formation of polarons, one in the visible region (pF+* at 580 nm, pF-* at 600 nm) and another in the near-IR region. Polyfluorenes (pF) were synthesized having anthraquinone (AQ) or naphtylimide (NI) end caps that trap electrons or di-p-tolylaminophenyl
Trapping the Light Fantastic | U.S. DOE Office of Science (SC)
Trapping the Light Fantastic Trapping the Light Fantastic Discovery & Innovation Stories of Discovery & Innovation Brief Science Highlights SBIR/STTR Highlights Contact Information Office of Science U.S. Department of Energy 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5430 07.07.11 Trapping the Light Fantastic New solar cell design uses advanced optics and nanotechnology to maximize performance and minimize cost. Discovery moves from lab bench to initial commercial scale-up inside a year. Print Text Size: A A A Subscribe FeedbackShare Page Click to enlarge photo. Enlarge Photo A 3-D graphic showing Si wires, transparent polymer, light-scattering particles, anti-reflective coating and back-reflector Image courtesy of California Institute of Technology Schematic of Atwater team's silicon nanowire solar cell.
Ancient Lava Flows Trap CO2 for Long-Term Storage in Big Sky Injection |
Ancient Lava Flows Trap CO2 for Long-Term Storage in Big Sky Ancient Lava Flows Trap CO2 for Long-Term Storage in Big Sky Injection Ancient Lava Flows Trap CO2 for Long-Term Storage in Big Sky Injection August 13, 2013 - 1:59pm Addthis Photo by J.D. Griggs, courtesy of U.S.Geological Survey Photo by J.D. Griggs, courtesy of U.S.Geological Survey For Additional Information To learn more about the carbon storage projects in which NETL is involved, please visit the NETL Carbon Storage website How can a prehistoric volcanic eruption help us reduce the amount of CO2 released into the atmosphere today? The answer is found in the basalt formations created by the lava - formations that can be used as sites for injecting carbon dioxide (CO2) captured from industrial sources in a process called carbon capture and storage (CCS).
Geek-Up[11.19.2010]: Molecular Stencils, GRETINA and Trapped Antimatter |
Geek-Up[11.19.2010]: Molecular Stencils, GRETINA and Trapped Geek-Up[11.19.2010]: Molecular Stencils, GRETINA and Trapped Antimatter Geek-Up[11.19.2010]: Molecular Stencils, GRETINA and Trapped Antimatter November 19, 2010 - 5:16pm Addthis An optical micrograph of a polymer film that self-assembles into ordered nanoscale structures. | Photo Courtesy of Argonne National Laboratory An optical micrograph of a polymer film that self-assembles into ordered nanoscale structures. | Photo Courtesy of Argonne National Laboratory Niketa Kumar Niketa Kumar Public Affairs Specialist, Office of Public Affairs At Argonne National Laboratory, scientists have developed a technique that may lead to more efficient, lower cost solar energy technologies. Argonne nanoscientist Seth Darling and chemist Jeff Elam have engineered a method
The laser ion source trap for highest isobaric selectivity in online exotic isotope production
The improvement in the performance of a conventional laser ion source in the laser ion source and trap (LIST) project is presented, which envisages installation of a repeller electrode and a linear Paul trap/ion guide structure. This approach promises highest isobaric purity and optimum temporal and spatial control of the radioactive ion beam produced at an online isotope separator facility. The functionality of the LIST was explored at the offline test separators of University of Mainz (UMz) and ISOLDE/CERN, using the UMz solid state laser system. Ionization efficiency and selectivity as well as time structure and transversal emittance of the produced ion beam was determined. Next step after complete characterization is the construction and installation of the radiation-hard final trap structure and its first online application.
Schwellnus, F.; Gottwald, T.; Mattolat, C.; Wendt, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Blaum, K. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Catherall, R.; Crepieux, B.; Fedosseev, V.; Marsh, B.; Rothe, S.; Stora, T. [CERN, CH-1211 Geneva 23 (Switzerland); Kluge, H.-J. [GSI, Planckstrasse 1, D-64291 Darmstadt (Germany)
Trapping Fermionic $^{40}$K and Bosonic $^{87}$Rb on a Chip
We demonstrate the loading of a Bose-Fermi mixture into a microfabricated magnetic trap. In a single-chamber vacuum system, laser-cooled atoms are transported to the surface of a substrate on which gold wires have been microfabricated. The magnetic field minimum formed near these current-carrying wires is used to confine up to $6\\times10^4$ neutral $^{40}$K atoms. In addition, we can simultaneously load $2 \\times 10^5$ $^{87}$Rb atoms, demonstrating the confinement of two distinct elements with such a trap. In a sequence optimized for $^{87}$Rb alone, we observe up to $1 \\times 10^7$ trapped atoms. We describe in detail the experimental apparatus, and discuss prospects for evaporative cooling towards quantum degeneracy in both species.
S. Aubin; M. H. T. Extavour; S. Myrskog; L. J. LeBlanc; J. Esteve; S. Singh; P. Scrutton; D. McKay; R. McKenzie; I. D. Leroux; A. Stummer; J. H. Thywissen
Characterization of fluorescence collection optics integrated with a micro-fabricated surface electrode ion trap
One of the outstanding challenges for ion trap quantum information processing is to accurately detect the states of many ions in a scalable fashion. In the particular case of surface traps, geometric constraints make imaging perpendicular to the surface appealing for light collection at multiple locations with minimal cross-talk. In this report we describe an experiment integrating Diffractive Optic Elements (DOE's) with surface electrode traps, connected through in-vacuum multi-mode fibers. The square DOE's reported here were all designed with solid angle collection efficiencies of 3.58%; with all losses included a detection efficiency of 0.388% (1.02% excluding the PMT loss) was measured with a single Ca+ ion. The presence of the DOE had minimal effect on the stability of the ion, both in temporal variation of stray electric fields and in motional heating rates.
Clark, Craig R; Ellis, A R; Hunker, Jeff; Kemme, Shanalyn A; Maunz, Peter; Tabakov, Boyan; Tigges, Chris; Stick, Daniel L
Craig R. Clark; Chin-wen Chou; A. R. Ellis; Jeff Hunker; Shanalyn A. Kemme; Peter Maunz; Boyan Tabakov; Chris Tigges; Daniel L. Stick
Enhanced Efficiency of Light-Trapping Nanoantenna Arrays for Thin Film Solar Cells
We suggest a novel concept of efficient light-trapping structures for thin-film solar cells based on arrays of planar nanoantennas operating far from plasmonic resonances. The operation principle of our structures relies on the excitation of chessboard-like collective modes of the nanoantenna arrays with the field localized between the neighboring metal elements. We demonstrated theoretically substantial enhancement of solar-cell short-circuit current by the designed light-trapping structure in the whole spectrum range of the solar-cell operation compared to conventional structures employing anti-reflecting coating. Our approach provides a general background for a design of different types of efficient broadband light-trapping structures for thin-film solar-cell technologically compatible with large-area thin-film fabrication techniques.
Simovski, Constantin R; Voroshilov, Pavel M; Guzhva, Michael E; Belov, Pavel A; Kivshar, Yuri S
Photoluminescence Blinking Dynamics of Colloidal Quantum Dots in the Presence of Controlled External Electron Traps
The effect of the external charge trap on the photoluminescence blinking dynamics of individual colloidal quantum dots is investigated with a series of colloidal quantum dot-bridge-fullerene dimers with varying bridge lengths, where the fullerene moiety acts as a well-defined, well-positioned external charge trap. It is found that charge transfer followed by charge recombination is an important mechanism in determining the blinking behavior of quantum dots when the external trap is properly coupled with the excited state of the quantum dot, leading to a quasi-continuous distribution of 'on' states and an early fall-off from a power-law distribution for both 'on' and 'off' times associated with quantum dot photoluminescence blinking.
Cotlet, M.; Xu, Z.
A microscopic model of electronic field noise heating in ion traps
Motional heating of ions in micro-fabricated traps is a challenge hindering experimental realization of large-scale quantum processing devices. Recently a series of measurements of the heating rates in surface-electrode ion traps characterized their frequency, distance, and temperature dependencies, but our understanding of the microscopic origin of this noise is still vague. In this work we develop a theoretical model for the electric field noise which is associated with a random distribution of adsorbed atoms on the trap electrode surface. By using first principle calculations of the fluctuating dipole moments of the adsorbed atoms we evaluate the distance, frequency and temperature dependence of the resulting electric field fluctuation spectrum.Our theory calculates the noise spectrum beyond the standard scenario of two-level fluctuators, by incorporating all the relevant vibrational states. The $1/f$ noise is shown to commence at roughly the frequency of the fundamental phonon transition rate and the $d^{...
Safavi-Naini, A; Weck, P; Sadeghpour, H R
A proposal is given of an approach to a fission-product trapping system which appears feasible on the basis of thermodynamic and other data available. Reactor and trapping conditions are outlined. The half-lives, fission yields, and volatility of the fission products of interest are described. To provide the most effective retention at elevated temperatures, two types of reagents are required: a highly electropositive metal that will not melt or appreciably vaporize and which will form stable non-volatile compounds with non-metallic or near non-metallic fission products; and a reagent to provide a highly electronegative element to form stable, non-volatile compounds with metallic fission products. Thermodynamic properties are included for compounds formed by reactions between the fission products and the trapping reagents. (B.O.G.)
Zumwalt, L.R.
Electron Traps Detected in p-type GaAsN Using Deep Level Transient Spectroscopy
The GaAsN alloy can have a band gap as small as 1.0 eV when the nitrogen composition is about 2%. Indium can also be added to the alloy to increase lattice matching to GaAs and Ge. These properties are advantageous for developing a highly-efficient, multi-junction solar cell. However, poor GaAsN cell properties, such as low open-circuit voltage, have led to inadequate performance. Deep-level transient spectroscopy of p-type GaAsN has identified an electron trap having an activation energy near 0.2 eV and a trap density of at least 1016 cm-3. This trap level appears with the addition of small amounts of nitrogen to GaAs, which also corresponds to an increased drop in open-circuit voltage.
Johnston, S.; Kurtz, S.; Friedman, D.; Ptak, A.; Ahrenkiel, R.; Crandall, R.
Light Trapping for High Efficiency Heterojunction Crystalline Si Solar Cells: Preprint
Light trapping plays an important role to achieve high short circuit current density (Jsc) and high efficiency for amorphous/crystalline Si heterojunction solar cells. Si heterojunction uses hydrogenated amorphous Si for emitter and back contact. This structure of solar cell posses highest open circuit voltage of 0.747 V at one sun for c-Si based solar cells. It also suggests that over 25% record-high efficiency is possible with further improvement of Jsc. Light trapping has two important tasks. The first one is to reduce the surface reflectance of light to zero for the solar spectrum that Si has a response. The second one is to increase the effective absorption length to capture all the photon. For Si heterojunction solar cell, surface texturing, anti-reflectance indium tin oxides (ITO) layer at the front and back are the key area to improve the light trapping.
Wang, Q.; Xu, Y.; Iwaniczko, E.; Page, M.
Trapping and Transportation of Adult and Juvenile Salmon in the Lower Umatilla River in Northeast Oregon: Umatilla River Basin Trap and Haul Program, October 1994-September 1995.
Threemile Falls Dam (Threemile Dam), located near the town of Umatilla, is the major collection and counting point for adult salmonids returning to the Umatilla River. Returning salmon and steelhead were collected at Threemile Dam from August 26, 1994 to June 27, 1995. A total of 1,531 summer steelhead (Oncorhynchus mykiss); 688 adult, 236 jack, and 368 subjack fall chinook (O. tshawvtscha); 984 adult and 62 jack coho (O. kisutch) ; and 388 adult and 108 jack spring chinook (O. tshawvtscha) were collected. All fish were trapped at the east bank facility. Of the fish collected, 971 summer steelhead; 581 adult and 27 jack fall chinook; 500 adult and 22 jack coho; and 363 adult and 61 jack spring chinook were hauled upstream from Threemile Dam. There were also 373 summer steelhead; 12 adult, 186 jack and 317 subjack fall chinook; 379 adult and 32 jack coho; and 15 adult and one jack spring chinook released at Threemile Dam. In addition, 154 summer steelhead were hauled to Bonifer and Minthorn for brood. The Westland Canal facility, located near the town of Echo, is the major collection point for outmigrating juvenile salmonids and steelhead kelts. The facility operated for a total of 179 days between December 2, 1994 and July 19, 1995. During that period, fish were bypassed back to the river 137 days and were trapped 42 days. Three steelhead kelts and an estimated 1,560 pounds of juvenile fish were transported from the Westland Canal trap to the Umatilla River boat ramp at rivermile 0.5. Approximately 98% of the fish transported this year were salmonids. The Threemile Dam west bank juvenile bypass began operating March 25, 1995 and was closed on June 16, 1995. The juvenile trap was operated by Oregon Department of Fish and Wildlife research personnel from April 1, 1995 through the summer to monitor juvenile outmigration.
Trapping capacity of fault zones, downdip Yegua Formation, Texas Gulf Coast basin
The homogenization of sediment from shearing forms traps in both the hanging wall and footwall due to capillary pressure differences. The sheared zone associated with large faults can form traps. Sheared zones associated with small faults can compartmentalize reservoirs leading to unreliable estimates of reserves. Measured values of capillary pressure were compared with estimated capillary pressure values from four correlation methods. Based on comparison of estimated pressure with measured pressure, Pittman's method gave the most reliable results for predicting capillary pressure and therefore the height of the oil column. However, all methods for predicting capillary pressure worked well for samples with porosities above 20% and permeabilities above 100 md. Hydrocarbon column heights were then determined from the capillary pressure values. The large sheared zone of the Cities Service Dincans1 (CD1) well, Toro Grande field, Jackson County, has a predicted trapping capacity of up to 1,961 ft of oil at 10,000 ft depth and 35% saturation of oil. Shearing is mostly at the hand specimen scale in the General Crude Kirby Lumber 2 (GCK2) well, East Sour Lake field, Hardin County, which has a maximum trapping capacity of 111 ft. From this study, it is then concluded that a homogenized sheared zone, formed from ductile deformation of sand and shale layers can form a trap to hydrocarbons. Sheared zones may be thick zones, on the order of feet, or smaller zones at microscopic or hand specimen scale. The larger the sheared zone is, the greater the trapping capacity of the fault.
Hintz, Jena Christine
Mitigation of Sulfur Effects on a Lean NOx Trap Catalyst by Sorbate Reapplication
Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by >90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as "regeneration" since the catalyst is reactivated for more NOx trapping. Natural gas combusted over partial oxidation catalysts in the exhaust can be used to obtain the rich exhaust conditions necessary for catalyst regeneration. Thus, the lean NOx trap technology is well suited for lean natural gas engine applications. One potential limitation of the lean NOx trap technology is sulfur poisoning. Sulfur compounds directly bond to the NOx trapping sites of the catalyst and render them ineffective; over time, the sulfur poisoning leads to degradation in overall NOx reduction performance. In order to mitigate the effects of sulfur poisoning, a process has been developed to restore catalyst activity after sulfur poisoning has occurred. The process is an aqueous-based wash process that removes the poisoned sorbate component of the catalyst. A new sorbate component is reapplied after removal of the poisoned sorbate. The process is low cost and does not involve reapplication of precious metal components of the catalyst. Experiments were conducted to investigate the feasibility of the washing process on a lean 8.3-liter natural gas engine on a dynamometer platform. The catalyst was rapidly sulfur poisoned with bottled SO2 gas; then, the catalyst sorbate was washed and reapplied and performance was re-evaluated. Results show that the sorbate reapplication process is effective at restoring lost performance due to sulfur poisoning. Specific details relative to the implementation of the process for large stationary natural gas engines will be discussed.
Parks, II, James E [ORNL
Influence of trapping potentials on the phase diagram of bosonic atoms in optical lattices
We study the effect of external trapping potentials on the phase diagram of bosonic atoms in optical lattices. We introduce a generalized Bose-Hubbard Hamiltonian that includes the structure of the energy levels of the trapping potential, and show that these levels are in general populated both at finite and zero temperature. We characterize the properties of the superfluid transition for this situation and compare them with those of the standard Bose-Hubbard description. We briefly discuss similar behaviors for fermionic systems.
Giampaolo, S.M.; Illuminati, F.; Mazzarella, G.; De Siena, S. [Dipartimento di Fisica 'E. R. Caianiello', Universita di Salerno, INFM UdR di Salerno, INFN Sezione di Napoli-Gruppo Collegato di Salerno, I-84081 Baronissi, SA (Italy)
S. M. Giampaolo; F. Illuminati; G. Mazzarella; S. De Siena
Measurement of localized heating in the focus of an optical trap
Localized heating in the focus of an optical trap operating in water can result in a temperature rise of several kelvins. We present spatially resolved measurements of the refractive-index distribution induced by the localized heating produced in an optical trap and infer the temperature distribution. We have determined a peak temperature rise in water of 4 K in the focus of a 985-nm-wavelength 55-mW laser beam. The localized heating is directly proportional to power and the absorption coefficient. The temperature distribution is in excellent agreement with a model based on the heat equation. (c) 2000 Optical Society of America.
Celliers, Peter M. [Lawerence Livermore National Laboratory, P. O. Box 808, Livermore, California 94550 (United States); Conia, Jerome [Cell Robotics, Inc., 2715 Broadbent Parkway NE, Albuquerque, New Mexico 87107 (United States)
Pore-scale study of capillary trapping mechanism during CO2 injection in geological formations
Geological sequestration of CO{sub 2} gas emerged as a promising solution for reducing amount of green house gases in atmosphere. A number of continuum scale models are available to describe the transport phenomena of CO{sub 2} sequestration. These models rely heavily on a phenomenological description of subsurface transport phenomena and the predictions can be highly uncertain. Pore-scale models provide a better understanding of fluid displacement processes, nonetheless such models are rare. In this work we use a Smoothed Particle Hydrodynamics (SPH) model to study pore-scale displacement and capillary trapping mechanisms of super-critical CO{sub 2} in the subsurface. Simulations are carried out to investigate the effects of gravitational, viscous, and capillary forces in terms of Gravity, Capillary, and Bond numbers. Contrary to the other published continuum scale investigations, we found that not only Gravity number but also Capillary number plays an important role on the fate of injected CO{sub 2}. For large Gravity numbers (on the order of 10), most of the injected CO{sub 2} reaches the cap-rock due to gravity segregation. A significant portion of CO{sub 2} gets trapped by capillary forces when Gravity number is small (on the order of 0.1). When Gravity number is moderately high (on the order of 1), trapping patterns are heavily dependent on Capillary number. If Capillary number is very small (less than 0.001), then capillary forces dominate the buoyancy forces and a significant fraction of injected CO{sub 2} is trapped by the capillary forces. Conversely, if Capillary number is high (higher than 0.001), capillary trapping is relatively small since buoyancy dominates the capillary forces. In addition, our simulations reveal different types of capillary trapping and flow displacement mechanisms during and after injection. In gravity dominated cases leave behind was the widespread trapping mechanism. Division was the primary trapping mechanism in viscous dominated cases. In capillary dominated cases, snap-off of the CO{sub 2} plume is the most commonly observed displacement mechanism. Large CO{sub 2} blobs are created due to coalescence mechanism.
Bandara, Uditha C.; Tartakovsky, Alexandre M.; Palmer, Bruce J.
Soliton propagation, reflection, and transmission in an inhomogeneous plasma with trapped electrons
Transmission and reflection of solitons from a semitransparent grid in an inhomogeneous plasma in the presence of trapped electrons is studied analytically. Conditions are obtained for the obliqueness of the propagation and the drift velocity of ions for the soliton transmission and reflection. Also, a transmission-reflection conservation law is derived. The contribution of trapped electrons to the solitons' propagation and their reflection and transmission is examined through energy, amplitude, and width of the solitons, in addition to the effect of temperature and drift of the ions.
Aziz, Farah; Malik, Hitendra K.; Stroth, Ulrich [Institut fuer Plasmaforschung, Universitaet Stuttgart, 70569 Stuttgart (Germany)
Electric field noise above surfaces: a model for heating rate scaling law in ion traps
We present a model for the scaling laws of the electric field noise spectral density as a function of the distance, $d$, above a conducting surface. Our analytical approach models the patch potentials by introducing a correlation length, $\\zeta$, of the electric potential on the surface. The predicted scaling laws are in excellent agreement with two different classes of experiments (cold trapped ions and cantilevers), that span at least four orders of magnitude of $d$. According to this model, heating rate in miniature ion traps could be greatly reduced by proper material engineering.
Dubessy, Romain; Guidoni, Luca
Romain Dubessy; Thomas Coudreau; Luca Guidoni
Trapped-Particle Instability Leading to Bursting in Stimulated Raman Scattering Simulations
Nonlinear, kinetic simulations of Stimulated Raman Scattering (SRS) for laser-fusion-relevant conditions present a bursting behavior. Different explanations for this regime has been given in previous studies: Saturation of SRS by increased nonlinear Landau damping [K. Estabrook et al., Phys. Fluids B 1 (1989) 1282] and detuning due to the nonlinear frequency shift of the plasma wave [H.X. Vu et al., Phys. Rev. Lett. 86 (2001) 4306]. Another mechanism, also assigning a key role to the trapped electrons, is proposed here: The break-up of the plasma wave through the trapped-particle instability.
S. Brunner; E. Valeo
Some effects of parallel energy propagation on the structure of dissipative trapped electron modes
The limitation of ballooning by parallel energy propagation is investigated for the dissipative trapped electron mode, wherein the local energy influx is proportional to the poloidally dependent trapped particle fraction. For small energetic asymmetries [mg less than 2.5 ($Omega$/sub i/a/c/sub s/) (a/R/ sup $sup 3$/$sub 4$/] the structure along the field line is predominantly a phase shift, dictated by the condition that the asymmetric energy input be compensated by parallel energy flow. For large asymmetry, mode number, and parallel arc length, the phase and amplitude variations necessitate an integral equation treatment. (auth)
Sauthoff, N. R.
Static and Dynamic Properties of Trapped Fermionic Tonks-Girardeau Gases
We investigate some exact static and dynamic properties of one-dimensional fermionic Tonks-Girardeau gases in tight de Broglie waveguides with attractive p-wave interactions induced by a Feshbach resonance. A closed form solution for the one-body density matrix for harmonic trapping is analyzed in terms of its natural orbitals, with the surprising result that for odd, but not for even, numbers of fermions the maximally occupied natural orbital coincides with the ground harmonic oscillator orbital and has the maximally allowed fermionic occupancy of unity. The exact dynamics of the trapped gas following turnoff of the p-wave interactions are explored.
Model simulations of continuous ion injection into electron-beam ion source trap with slanted electrostatic mirror
The efficiency of trapping ions in an electron-beam ion source (EBIS) is of primary importance for many applications requiring operations with externally produced ions: RIA breeders, ion sources, and traps. At the present time, the most popular method of ion injection is pulsed injection, when short bunches of ions get trapped in a longitudinal trap while traversing the trap region. Continuous trapping is a challenge for EBIS devices because mechanisms which reduce the longitudinal ion energy per charge in a trap (cooling with residual gas, energy exchange with other ions, and ionization) are not very effective, and accumulation of ions is slow. A possible approach to increase trapping efficiency is to slant the mirror at the end of the trap which is opposite to the injection end. A slanted mirror will convert longitudinal motion of ions into transverse motion, and, by reducing their longitudinal velocity, prevent these ions from escaping the trap on their way out. The trade-off for the increased trapping efficiency this way is an increase in the initial transverse energy of the accumulated ions. The slanted mirror can be realized if the ends of two adjacent electrodes, drift tubes, which act as an electrostatic mirror, are machined to produce a slanted gap, rather than an upright one. Applying different voltages to these electrodes will produce a slanted mirror. The results of two-dimensional (2D) and three-dimensional (3D) computer simulations of the ion injection into an EBIS are presented using simplified models of an EBIS with conical (2D simulations) and slanted (3D simulations) mirror electrodes.
Pikin, A.; Kponou, A.; Alessi, J. G.; Beebe, E. N.; Prelec, K.; Raparia, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)
PHYSICAL REVIEW A 84, 022343 (2011) Coherence of a qubit stored in Zeeman levels of a single optically trapped atom
experimentally investigate the coherence properties of a qubit stored in the Zeeman substates of the 52 S1/2, F = 1 hyperfine ground level of a single optically trapped 87 Rb atom. Larmor precession of a single and the quantum repeater [1]. There, ground states of trapped atoms or ions are ideal candidates
Weinfurter, Harald
ESI/Ion Trap/Ion Mobility/Time-of-Flight Mass Spectrometry for Rapid and Sensitive Analysis of
discuss a new separation strategy for biomolecules that is based on differences in ion mobilitiesESI/Ion Trap/Ion Mobility/Time-of-Flight Mass Spectrometry for Rapid and Sensitive Analysis* Department of Chemistry, Indiana University, Bloomington, Indiana 47405 An ion trap/ion mobility
Anomalous electron trapping by magnetic flux tubes and electric current vortices
Anomalous electron trapping by magnetic flux tubes and electric current vortices F. Bentosela, a current vortex in the plane. In this case the flux is zero; there is a pair of bound states for a weak with a nonhomogeneous magnetic field B , and investigate the corresponding Pauli Hamiltonian. We prove a lower bound
Lattice Trapping Barriers to Brittle Fracture N. Bernstein and D.W. Hess*
Lattice Trapping Barriers to Brittle Fracture N. Bernstein and D.W. Hess* Center for Computational HPCMPO CHSSI program, and D.W. H. the National Science Foundation. *Current address: Division, 4029 (1998). [18] N. Bernstein and D.W. Hess, in Multiscale Modeling of Materials--2000, edited by L. P
Dynamics of a single trapped ion inside a nonideal QED cavity at zero temperature
We consider a system consisting of a single ion in a Paul trap coupled to a cavity electromagnetic field mode. We analyze the fidelity of a scheme for quantum swapping between vibrational and cavity field states, when the system is in contact with a reservoir at zero temperature.
Rangel, R.; Zagury, N. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21945-970 Rio de Janeiro (Brazil); Massoni, E. [Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado 1761, Lima (Peru)
Trapped Lee Waves Observed during PYREX by Constant Volume Balloons: Comparison with Meso-NH Simulations
The main objective of the present paper is the use of a constant volume balloon (CVB) as a tool to (i) study trapped lee waves and (ii) assess the forecasting capability of a nonhydrostatic numerical model. Then, CVB data obtained during the ...
Ernest N�Dri Koffi; Marc Georgelin; Bruno Benech; Evelyne Richard
Model for hydrogen isotope backscattering, trapping and depth profiles in C and a-Si
A model of low energy hydrogen trapping and backscattering in carbon and a-silicon is described. Depth profiles are calculated and numerical results presented for various incident angular and energy distributions. The calculations yield a relation between depth profiles and the incident ion energy distribution. The use of this model for tokamak plasma diagnosis is discussed.
Cohen, S.A.; McCracken, G.M.
Solubility trapping in formation water as dominant CO2 sink in natural gas fields
LETTERS Solubility trapping in formation water as dominant CO2 sink in natural gas fields Stuart M removal in nine natural gas fields in North America, China and Europe, using noble gas and carbon isotope tracers. The natural gas fields investigated in our study are dominated by a CO2 phase and provide
Haszeldine, Stuart
Trapping of Waves by a Constant Slope internal Interface in a Two-Layer Ocean
It is well known that �edge� and �continental shelf� waves can be trapped by a constant slope nearshore bottom; in a two-layer ocean of great constant depth, a constant slope internal interface, as well as the associated geostrophic current, can ...
Henri Lacombe
Trapping Conformational Intermediate States in the Reaction Center Protein from Photosynthetic Bacteria
+, and reduced QB -, return to the ground state at cryogenic temperature in a conformation that allows a high yield of QB reduction. Thus, RCs frozen under illumination are found to be trapped above the ground 16 ( 3 meV. Thus, there are several conformational substates along the reaction coordinate
Gunner, Marilyn
Finite beta and resonant electron effects on trapped-electron instabilities
Finite $beta$ (plasma pressure/magnetic pressure) and resonant electron effects on the dissipative trapped-electron instabilities are analyzed. These modifications are shown to have a strong stabilizing influence on the finite ion gyroradius and electron temperature gradient driven modes, respectively. For relevant tokamak parameters complete stabilization may be possible. Stability criteria for radially local and nonlocal cases are presented. (auth)
Tang, W.M.; Liu, C.S.; Rosenbluth, M.N.; Catto, P.J.; Callen, J.D.
Steady Wind-driven Upwelling in the Presence of a Baroclinic Coastally Trapped Jet
The usual two-layer model for steady wind-driven upwelling along a uniform coastline is extended to incorporate the effects of an upper-layer jet trapped against the coast. The characteristic width of the jet is the internal deformation radius, ...
A. E. Hay; E. D. Kinsella
Beauty is more attractive: Particle Production and Moduli trapping with Higher Dimensional Interaction
We study quantum effects on moduli dynamics arising from the particle production near the enhanced symmetry point (ESP). We paid special attention to the non-conventional interactions, which are suppressed by the cutoff scale of the effective action but the power of the field is larger. This kind of interaction is sometimes called the "higher dimensional" interaction. Considering the higher dimensional interaction, we find that the particle production is significant in a large area, which is even larger than the area that is expected from the conventional interaction. It is possible to find this possibility from the trivial adiabatic condition; however the quantitative estimation of the particle production and the trapping of the field in motion are far from trivial. In this paper we study the particle production and the trapping in detail, using both the analytical and the numerical calculations, to find a clear and intuitive result that supports trapping in a vast variety of theories. Our study shows that the trapping is possible by the non-conventional interaction that has been disregarded in previous works. Some phenomenological models of the particle physics will be mentioned to complement the discussion.
Seishi Enomoto; Satoshi Iida; Nobuhiro Maekawa; Tomohiro Matsuda
Laser cooling and sympathetic cooling in a linear quadrupole rf trap
An investigation of the sympathetic cooling method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of rf heating rates on the ion temperature, trapping parameters, and the number of ions is obtained. New rf heating mechanism affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and the influence of the rf heating rates on the fluorescence lineshapes is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.
Ryjkov, Vladimir Leonidovich
Final Report - Advanced Ion Trap Mass Spectrometry Program - Oak Ridge National Laboratory - Sandia National Laboratory
This report covers the three main projects that collectively comprised the Advanced Ion Trap Mass Spectrometry Program. Chapter 1 describes the direct interrogation of individual particles by laser desorption within the ion trap mass spectrometer analyzer. The goals were (1) to develop an ''intelligent trigger'' capable of distinguishing particles of biological origin from those of nonbiological origin in the background and interferent particles and (2) to explore the capability for individual particle identification. Direct interrogation of particles by laser ablation and ion trap mass spectrometry was shown to have good promise for discriminating between particles of biological origin and those of nonbiological origin, although detailed protocols and operating conditions were not worked out. A library of more than 20,000 spectra of various types of biological particles has been assembled. Methods based on multivariate analysis and on neural networks were used to discriminate between particles of biological origin and those of nonbiological origin. It was possible to discriminate between at least some species of bacteria if mass spectra of several hundred similar particles were obtained. Chapter 2 addresses the development of a new ion trap mass analyzer geometry that offers the potential for a significant increase in ion storage capacity for a given set of analyzer operating conditions. This geometry may lead to the development of smaller, lower-power field-portable ion trap mass spectrometers while retaining laboratory-scale analytical performance. A novel ion trap mass spectrometer based on toroidal ion storage geometry has been developed. The analyzer geometry is based on the edge rotation of a quadrupolar ion trap cross section into the shape of a torus. Initial performance of this device was poor, however, due to the significant contribution of nonlinear fields introduced by the rotation of the symmetric ion-trapping geometry. These nonlinear resonances contributed to poor mass resolution and sensitivity and to erratic ion ejection behavior. To correct for these nonlinear effects, the geometry of the toroid ion trap analyzer has been modified to create an asymmetric torus, as first suggested by computer simulations that predicted significantly improved performance and unit mass resolution for this geometry. A reduced-sized version (one-fifth scale) has been fabricated but was not tested within the scope of this project. Chapter 3 describes groundbreaking progress toward the use of ion-ion chemistry to control the charge state of ions formed by the electrospray ionization process, which in turn enables precision analysis of whole proteins. In addition, this technique may offer the unique possibility of a priori identification of unknown biological material when employed with existing proteomics and genomic databases. Ion-ion chemistry within the ion trap was used to reduce the ions in highly charged states to states of +1 and +2 charges. Reduction in charge greatly simplifies identification of molecular weights of fragments from large biological molecules. This technique enables the analysis of whole proteins as biomarkers for the detection and identification of all three classes of biological weapons (bacteria, toxins, and viruses). In addition to methods development, tests were carried out with samples of tap water, local creek water, and soil (local red clay) spiked with melittin (bee venom), cholera toxin, and virus MS2. All three analytes were identified in tap water and soil; however, all three were problematic for detection in creek water at concentrations of 1 nM. More development of methods is needed.
Whitten, W.B.
Observations of seasonal variations in atmospheric greenhouse trapping and its enhancement at high sea surface temperature
The correlation between observed values of atmospheric greenhouse trapping and sea surface temperature is found to vary seasonally. Atmospheric greenhouse trapping is defined here as the difference between infrared emissions from the earth's surface and infrared emissions from the top of the atmosphere through cloudless skies. Infrared surface emissions are calculated from known sea surface temperatures; emissions from the top of the atmosphere are taken from direct satellite measurements. Atmospheric greenhouse trapping at the same sea surface temperature is greater in the winter than in the summer over temperate oceans. In subtropical latitudes, the opposite is true. At surface temperatures above approximately 298 K, atmospheric greenhouse trapping is found to increase even more rapidly from regions of lower sea surface temperature to regions of higher surface temperature than infrared surface emissions. The causes for this [open quotes]super[close quotes] greenhouse effect are explored, and four processes are found to contribute. Water vapor continuum absorption and thermodynamically controlled increases in water vapor concentration at constant relative humidity with increasing atmospheric temperature make significant contributions, but do not explain the entire super greenhouse effect. To explain the observations of atmospheric greenhouse trapping, the upper and middle troposphere, must be increasingly moist over the warmest sea surface temperatures, while the atmospheric temperature profile becomes increasingly unstable. Regions with these high sea surface temperatures are also increasingly subject to deep convection, which suggests that convection moistens the upper and middle troposphere in regions of convective activity relative to nonconvective regions, resulting in the super greenhouse effect. Dynamic processes, along with local thermodynamic processes, are required to explain the observed super greenhouse effect. 30 refs., 3 figs., 2 tabs.
Hallberg, R. (Univ. of Washington, Seattle (United States)); Inamdar, A.K. (Scripps Institution of Oceanography, La Jolla, CA (United States))
Would you keep speeding through a speed trap if you got a ticket there before?
you keep speeding through a speed trap if you got a ticket there before? you keep speeding through a speed trap if you got a ticket there before? Probably (hopefully) not. Likewise, taking advantage of lessons learned on our capital asset and clean-up projects is not only fiscally prudent, but also just makes good common sense. DOE Order 413.3B "Program and Project Management for the Acquisition of Capital Assets" re- quires formal lessons learned to be documented for a project, as follows: Within 90 days of CD-3 approval, to cover up-front planning and design lessons learned Within 90 days of CD-4 approval, to cover project execution and facility start-up les- sons learned These should be formal documents and should be submitted to OECM for sharing throughout the
Analysis of Mineral Trapping for CO2 Disposal in Deep Aquifers
Reactive Geochemical Transport Simulation to Study Mineral Trapping Reactive Geochemical Transport Simulation to Study Mineral Trapping for CO 2 Disposal in Deep Saline Arenaceous Aquifers Tianfu Xu, John A. Apps, and Karsten Pruess Earth Sciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA Abstract. A reactive fluid flow and geochemical transport numerical model for evaluating long-term CO 2 disposal in deep aquifers has been developed. Using this model, we performed a number of sensitivity simulations under CO 2 injection conditions for a commonly encountered Gulf Coast sediment to analyze the impact of CO 2 immobilization through carbonate precipitation. Geochemical models are needed because alteration of the predominant host rock aluminosilicate minerals is very slow and is not
Precise asymptotics for the parabolic Anderson model with a moving catalyst or trap
We consider the solution $u\\colon [0,\\infty) \\times\\mathbb{Z}^d\\rightarrow [0,\\infty) $ to the parabolic Anderson model, where the potential is given by $(t,x)\\mapsto\\gamma\\delta_{Y_t}\\left(x\\right)$ with $Y$ a simple symmetric random walk on $\\mathbb{Z}^d$. Depending on the parameter $\\gamma\\in[-\\infty,\\infty)$, the potential is interpreted as a randomly moving catalyst or trap. In the trap case, i.e., $\\gamma0$), we consider the solution $u$ from the perspective of the catalyst, i.e., the expression $u(t,Y_t+x)$. Focusing on the cases where moments grow exponentially fast (that is, $\\gamma$ sufficiently large), we describe the moment asymptotics of the expression above up to equivalence. Here, it is crucial to prove the existence of a principal eigenfunction of the corresponding Hamilton operator. While this is well-established for the first moment, we have found an extension to higher moments.
Schnitzler, Adrian
Charge Trapping in Bright and Dark States of Coupled PbS Quantum Dot Films
Analysis of photoluminescence (PL) from chemically treated lead sulfide (PbS) quantum dot (QD) films versus temperature reveals the effects of QD size and ligand binding on the motion of carriers between bright and dark trap states. For strongly coupled QDs, the PL exhibits temperature-dependent quenching and shifting consistent with charges residing in a shallow exponential tail of quasi-localized states below the band gap. The depth of the tail varies from 15 to 40 meV, similar to or smaller than exponential band tail widths measured for polycrystalline Si. The trap state distribution can be manipulated with QD size and surface treatment, and its characterization should provide a clearer picture of charge separation and percolation in disordered QD films than what currently exists.
Gao, J.; Johnson, J. C.
Searching fast for a target on a DNA without falling to traps
Genomic expression depends critically both on the ability of regulatory proteins to locate specific target sites on a DNA within seconds and on the formation of long lived (many minutes) complexes between these proteins and the DNA. Equilibrium experiments show that indeed regulatory proteins bind tightly to their target site. However, they also find strong binding to other non-specific sites which act as traps that can dramatically increase the time needed to locate the target. This gives rise to a conflict between the speed and stability requirements. Here we suggest a simple mechanism which can resolve this long-standing paradox by allowing the target sites to be located by proteins within short time scales even in the presence of traps. Our theoretical analysis shows that the mechanism is robust in the presence of generic disorder in the DNA sequence and does not require a specially designed target site.
O. B�nichou; Y. Kafri; M. Sheinman; R. Voituriez
Water-waves modes trapped in a canal by a body with the rough surface
The problem about a body in a three dimensional infinite channel is considered in the framework of the theory of linear water-waves. The body has a rough surface characterized by a small parameter $\\epsilon>0$ while the distance of the body to the water surface is also of order $\\epsilon$. Under a certain symmetry assumption, the accumulation effect for trapped mode frequencies is established, namely, it is proved that, for any given $d>0$ and integer $N>0$, there exists $\\epsilon(d,N)>0$ such that the problem has at least $N$ eigenvalues in the interval $(0,d)$ of the continuous spectrum in the case $\\epsilon\\in(0,\\epsilon(d,N)) $. The corresponding eigenfunctions decay exponentially at infinity, have finite energy, and imply trapped modes.
G. Cardone; T. Durante; S. A. Nazarov
Polish permian basin: Lithofacies traps for gas within the Rotliegende deposits as a new exploration potential
Rotliegende deposits are the most prospective reservoir gas rocks in the Polish Permian basin. Thirty years of their exploration have led to location of numerous gas fields in the upper-most part of these series, particularly in the area of the Fore-Sudetic monocline. Up to this time, exploration studies concentrated mainly on structural objects, and most of the structures were positive gas traps. Well and seismic data also indicate an occurrence of lithofacies gas traps; they occur mainly in the sandstone zones within the fanglomerates surrounding the Wolsztyn Ridge. When comparing the facies regularities in the known gas fields in the German Permian basin (interfingering sandstones and claystones) to the facies patterns of the Polish Permian basin, one may suspect similar exploration possibilities. These are the first promising results. Advances in analysis of the Rotliegende depositional systems will enable us to create a new exploration potential.
Karnkowski, P.H. (Warsaw Univ., Warsaw (Poland))
Narrow-line magneto-optical cooling and trapping of strongly magnetic atoms
Laser cooling on weak transitions is a useful technique for reaching ultracold temperatures in atoms with multiple valence electrons. However, for strongly magnetic atoms a conventional narrow-line magneto-optical trap (MOT) is destabilized by competition between optical and magnetic forces. We overcome this difficulty in Er by developing an unusual narrow-line MOT that balances optical and magnetic forces using laser light tuned to the blue side of a narrow (8 kHz) transition. The trap population is spin-polarized with temperatures reaching below 2 microkelvin. Our results constitute an alternative method for laser cooling on weak transitions, applicable to rare-earth-metal and metastable alkaline earth elements.
Berglund, Andrew J; McClelland, Jabez J
Andrew J. Berglund; James L. Hanssen; Jabez J. McClelland
Three attractively interacting fermions in a harmonic trap: Exact solution, ferromagnetism, and high-temperature thermodynamics
Three fermions with strongly repulsive interactions in a spherical harmonic trap constitute the simplest nontrivial system that can exhibit the onset of itinerant ferromagnetism. Here, we present exact solutions for three trapped, attractively interacting fermions near a Feshbach resonance. We analyze energy levels on the upper branch of the resonance where the atomic interaction is effectively repulsive. When the s-wave scattering length a is sufficiently positive, three fully polarized fermions are energetically stable against a single spin-flip, indicating the possibility of itinerant ferromagnetism, as inferred in the recent experiment. We also investigate the high-temperature thermodynamics of a strongly repulsive or attractive Fermi gas using a quantum virial expansion. The second and third virial coefficients are calculated. The resulting equations of state can be tested in future quantitative experimental measurements at high temperatures and can provide a useful benchmark for quantum Monte Carlo simulations.
Liu Xiaji; Hu Hui; Drummond, Peter D. [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia)
Effect of trapping in a degenerate plasma in the presence of a quantizing magnetic field
Effect of trapping as a microscopic phenomenon in a degenerate plasma is investigated in the presence of a quantizing magnetic field. The plasma comprises degenerate electrons and non-degenerate ions. The presence of the quantizing magnetic field is discussed briefly and the effect of trapping is investigated by using the Fermi-Dirac distribution function. The linear dispersion relation for ion acoustic wave is derived in the presence of the quantizing magnetic field and its influence on the propagation characteristics of the linear ion acoustic wave is discussed. Subsequently, fully nonlinear equations for ion acoustic waves are used to obtain the Sagdeev potential and the investigation of solitary structures. The formation of solitary structures is studied both for fully and partially degenerate plasmas in the presence of a quantizing magnetic field. Both compressive and rarefactive solitons are obtained for different conditions of temperature and magnetic field.
Shah, H. A.; Iqbal, M. J.; Qureshi, M. N. S. [Department of Physics, GC University, Lahore 54000 (Pakistan); Tsintsadze, N. [Department of Physics, GC University, Lahore 54000 (Pakistan); Institute of Physics, Tbilisi 0177 (Georgia); Masood, W. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)
Design of a millimetre-scale magnetic surface trap for cold atoms
We study a novel millimetre-scale magnetic trap for ultracold atoms, in which the current carrying conductors can be situated outside the vacuum region, a few mm away from the atoms. This design generates a magnetic field gradient in excess of \\SI{1000}{G/cm} at a distance of \\SI{2}{mm} from the conductors. We perform electromagnetic and thermo-mechanical characterisation using Finite Element Methods (FEM). The predicted behaviour has been verified by electrical and thermal measurements on a prototype, but has not been implemented on an apparatus with cold atoms. Operating this trap at the highest gradient allows for rapid evaporative cooling comparable to that achieved by atom chips.
Trypogeorgos, Dimitris
Thermodynamics analogue for self-trapped spinning-stationary Madelung fluid
We discuss two-dimensional Madelung fluid dynamics whose irrotational case reduces into the Schr\\"odinger equation for a free single particle. We show that the self-trapped spinning-stationary Madelung fluid reported in the previous paper can be analogically identified as an equilibrium thermodynamics system. This is done by making correspondence between Shannon entropy over Madelung density and internal energy to be defined in the main text, respectively with thermal-entropy and thermal-internal energy of equilibrium thermodynamics system. This leads us to identify a Madelung fluid analog of thermal-temperature at the vanishing value of which the stationary Madelung fluid will be no more spinning and is equal to the quantum mechanical ground state of a particle trapped inside a cylindrical tube external potential.
Agung Budiyono
Spatial correlation functions for the collective degrees of freedom of many trapped ions
Spatial correlation functions provide a glimpse into the quantum correlations within a quantum system. Ions in a linear trap collectively form a nonuniform, discretized background on which a scalar field of phonons propagates. Trapped ions have the experimental advantage of each having their own "built-in" motional detector: electronic states that can be coupled, via an external laser, to the ion's vibrational motion. The post-interaction electronic state can be read out with high efficiency, giving a stochastic measurement record whose classical correlations reflect the quantum correlations of the ions' collective vibrational state. Here we calculate this general result, then we discuss the long detection-time limit and specialize to Gaussian states, and finally we compare the results for thermal versus squeezed states.
Nicolas C. Menicucci; G. J. Milburn
Trapping and diffusion of fission products in ThO2 and CeO2
The trapping and diffusion of Br, Rb, Cs and Xe in ThO2 and CeO{sub 2} have been studied using an Ab Initio total energy method in the local-density approximation of density functional theory. Fission products incorporated in cation mono-vacancy, cation-anion di-vacancy and Schottky defect sites are found to be stable, with the cation mono-vacancy being the preferred site in most cases. In both oxides, Rb and Cs are the most likely to be trapped, and Xe is more difficult to incorporate than other fission products. The energy barriers for migration of each species in ThO{sub 2} and CeO{sub 2} are also calculated. Alkali metals are relatively more mobile than other fission products, and bromine is the least mobile.
Xiao, Haiyan [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL; Weber, William J [ORNL
Thick-film technology for ultra high vacuum interfaces of micro-structured traps
We adopt thick-film technology to produce ultra high vacuum compatible interfaces for electrical signals. These interfaces permit voltages of hundreds of Volts and currents of several Amperes and allow for very compact vacuum setups, useful in quantum optics in general, and especially for quantum information and quantum simulations using miniaturized traps for ions or neutral atoms. Such printed circuits can also be useful as pure in-vacuum devices. We demonstrate a specific interface, which provides eleven current feedthroughs, more than 70 dc feedthroughs and a feedthrough for radio frequencies. We achieve a pressure in the low 1e-11mbar range and demonstrate the full functionality of the interface by trapping chains of cold ytterbium ions, which requires all of the signals mentioned above being present. In addition, a versatile multi-channel device for supplying precise time-dependent voltages has been developed.
Delia Kaufmann; Thomas Collath; M. Tanveer Baig; Peter Kaufmann; Eman Asenwar; Michael Johanning; Christof Wunderlich
Effects of trapping and finite temperature in a relativistic degenerate plasma
In the present work, we have undertaken, for the first time, investigation on the effect of trapping on the formation of solitary structures in relativistic degenerate plasmas. Such plasmas have been observed in dense astrophysical objects, and in laboratory these may result due to the interaction of intense lasers with matter. We have used the relativistic Fermi-Dirac distribution to describe the dynamics of the degenerate trapped electrons by solving the kinetic equation. The Sagdeev potential approach has been employed to obtain the arbitrary amplitude solitary structures both when the plasma has been considered cold and when small temperature effects have been taken into account. The theoretical results obtained have been analyzed numerically for different parameter values, and the results have been presented graphically.
Shah, H. A.; Qureshi, M. N. S. [Physics Department, GC University, Lahore 54000 (Pakistan); Masood, W. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000 (Pakistan); Tsintsadze, N. L. [Physics Department, GC University, Lahore 54000 (Pakistan); Institute of Physics, Georgian Academy of Sciences, Tblisi 380077 (Georgia)
Particle trap with dielectric barrier for use in gas insulated transmission lines
A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode. 7 figs.
Dale, S.J.
Storage of very cold neutrons in a trap with nano-structured walls
We report on storage of Very Cold Neutrons (VCN) in a trap with walls containing powder of diamond nanoparticles. The efficient VCN reflection is provided by multiple diffusive elastic scattering of VCN at single nanoparticles in powder. The VCN storage times are sufficiently long for accumulating large density of neutrons with complete VCN energy range of up to a few times 10(-4) eV. Methods for further improvements of VCN storage times are discussed.
E. V. Lychagin; A. Yu. Muzychka; V. V. Nesvizhevsky; G. Pignol; K. V. Protasov; A. V. Strelkov
Umklapp collisions and center of mass oscillation of a trapped Fermi gas
Starting from the the Boltzmann equation, we study the center of mass oscillation of a harmonically trapped normal Fermi gas in the presence of a one-dimensional periodic potential. We show that for values of the the Fermi energy above the first Bloch band the center of mass motion is strongly damped in the collisional regime due to umklapp processes. This should be contrasted with the behaviour of a superfluid where one instead expects the occurrence of persistent Josephson-like oscillations.
G. Orso; L. P. Pitaevskii; S. Stringari
Electron cyclotron resonance near the axis of the gas-dynamic trap
Propagation of an extraordinary electromagnetic wave in the vicinity of electron cyclotron resonance surface in an open linear trap is studied analytically, taking into account inhomogeneity of the magnetic field in paraxial approximation. Ray trajectories are derived from a reduced dispersion equation that makes it possible to avoid the difficulty associated with a transition from large propagation angles to the case of strictly longitudinal propagation. Our approach is based on the theory, originally developed by Zvonkov and Timofeev [Sov. J. Plasma Phys. 14, 743 (1988)], who used the paraxial approximation for the magnetic field strength, but did not consider the slope of the magnetic field lines, which led to considerable error, as has been recently noted by Gospodchikov and Smolyakova [Plasma Phys. Rep. 37, 768-774 (2011)]. We have found ray trajectories in analytic form and demonstrated that the inhomogeneity of both the magnetic field strength and the field direction can qualitatively change the picture of wave propagation and significantly affect the efficiency of electron cyclotron heating of a plasma in a linear magnetic trap. Analysis of the ray trajectories has revealed a criterion for the resonance point on the axis of the trap to be an attractor for the ray trajectories. It is also shown that a family of ray trajectories can still reach the resonance point on the axis if the latter generally repels the ray trajectories. As an example, results of general theory are applied to the electron cyclotron resonance heating experiment which is under preparation on the gas dynamic trap in the Budker Institute of Nuclear Physics [Shalashov et al., Phys. Plasmas 19, 052503 (2012)].
Bagulov, D. S. [Novosibirsk State University, Pirogova Street 2, Novosibirsk (Russian Federation); Kotelnikov, I. A. [Novosibirsk State University, Pirogova Street 2, Novosibirsk (Russian Federation); Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences, Akademika Lavrentyeva Prospect 11, 630090 Novosibirsk (Russian Federation)
Radiation detection system using semiconductor detector with differential carrier trapping and mobility
A system for obtaining improved resolution in relatively thick semiconductor radiation detectors, such as HgI.sub.2, which exhibit significant hole trapping. Two amplifiers are used: the first measures the charge collected and the second the contribution of the electrons to the charge collected. The outputs of the two amplifiers are utilized to unfold the total charge generated within the detector in response to a radiation event.
Whited, Richard C. (Santa Barbara, CA)
Cooling the Collective Motion of Trapped Ions to Initialize a Quantum Register
We report preparation in the ground state of collective modes of motion of two trapped 9Be+ ions. This is a crucial step towards realizing quantum logic gates which can entangle the ions' internal electronic states. We find that heating of the modes of relative ion motion is substantially suppressed relative to that of the center-of-mass modes, suggesting the importance of these modes in future experiments.
B. E. King; C. S. Wood; C. J. Myatt; Q. A. Turchette; D. Leibfried; W. M. Itano; C. Monroe; D. J. Wineland
Superconducting Magnetic Energy Storage in Trapped Field Magnets of High Temperature Superconductors
Superconducting permanent magnets for storing high magnetic fields can serve as a means of energy storage and are useful in applications ranging from motors and generators to fault current limiters and circuit breakers. This report presents the results of experimental studies on high temperature superconductors, which were successfully used to trap a record high stable magnetic field of 83,000 G at 54 K and 100,000 G at 42 K.
Thin Film Solar Cells with Light Trapping Transparent Conducting Oxide Layer
Thin film solar cells, if film thickness is thinner than the optical absorption length, typically give lower cell performance. For the thinner structure, electric current loss due to light penetration can offset the electric current gain obtained from higher built-in electric field. Light trapping schemes can increase the effective optical absorption length and thus enhance the electric current for thinner solar cells. Here a new light trapping scheme based on light trapping transparent conducting oxide layer (LT-TCO) is proposed to enhance the performance of thin film solar cells. Three different configurations of integrating the LT-TCO layer in solar cells are proposed and evaluated. This research aims to develop the LT-TCO layer with surface texture and good conductivity by pulsed laser deposition (PLD) technique at low temperature. The LT-TCO layer is fabricated by PLD deposition of Al-doped ZnO to achieve multilayer films by tuning of oxygen pressure. The light trapping effect is examined by optical transmittance measurement and the surface texture is characterized by transmission electron microscopy (TEM) technique. The conductivity of LT-TCO layer is measured by resistivity measurement. Thin film CdTe/CdS solar cells are fabricated by PLD technique to develop baseline solar cells for integration of LT-TCO layer. The as-deposited thin film solar cells show relatively low performance and are further processed with various post-deposition treatments to seek efficiency enhancement. The effects of different processes on cell performance are examined by electrical, optical, and microstructure studies. Air annealing of CdS layer and CdCl2 treatment of CdTe layer combined are found to yield the best cell performance. The fabrication issues that limit the cell performance are discussed and future optimizations in fabrication processes are suggested.
Lu, Tianlin
Integrated Status and Effectiveness Monitoring Program - Entiat River Snorkel Surveys and Rotary Screw Trap, 2007.
The USFWS Mid-Columbia River Fishery Resource Office conducted snorkel surveys at 24 sites during the summer and fall periods of 2006 survey periods as part of the Integrated Status and Effectiveness Monitoring Program in the Entiat River. A total of 37,938 fish from 15 species/genera and an unknown category were enumerated. Chinook salmon were the overall most common fish observed and comprised 15% of fish enumerated followed by rainbow trout (10%) and mountain whitefish (7%). Day surveys were conducted during the summer period 2007 (August), while night surveys were conducted during the fall 2007 (October) surveys. The USFWS Mid-Columbia River Fishery Resource Office (MCFRO) operated two rotary screw traps on the Entiat River as part of the Integrated Status and Effectiveness Monitoring Program (ISEMP) program from August through November of 2007. Along with the smolt traps, juvenile emigrants were also captured at remote locations throughout the Entiat watershed and its major tributary, the Mad River. A total of 999 wild Oncorhynchus mykiss and 5,107 wild run O. tshawytscha were PIT tagged during the study period. Rotary screw trap efficiencies averaged 22.3% for juvenile O. tshawytscha and 9.0% for juvenile O. mykiss. Rotary screw traps operated 7 days a week and remote capture operations were conducted when flow and temperature regimes permitted. This is third annual progress report to Bonneville Power Administration for the snorkel surveys conducted in the Entiat River as related to long-term effectiveness monitoring of restoration programs in this watershed. The objective of this study is to monitor the fish habitat utilization of planned in-stream restoration efforts in the Entiat River by conducting pre- and post-construction snorkel surveys at selected treatment and control sites.
Nelle, R.D.
A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode.
Novel Water-Neutral Diesel Fuel Processor and Sulfur TrapPrecision Combustion
Novel Water-Neutral Diesel Fuel Novel Water-Neutral Diesel Fuel Processor and Sulfur Trap-Precision Combustion Background Solid-Oxide Fuel Cell (SOFC) technology for auxiliary power units (APUs) offers the potential for major contributions toward Department of Energy (DOE) objectives such as clean energy deployment and improved efficiency. Reforming of conventional liquid fuels to produce synthesis gas (syngas) fuel for SOFC stacks is a practical approach for operating fuel cell APUs
Measurement of one-particle correlations and momentum distributions for trapped 1D gases
van Hove's theory of scattering of probe particles by a macroscopic target is generalized so as to relate the differential cross section for atomic ejection via stimulated Raman transitions to one-particle momentum-time correlations and momentum distributions of 1D trapped gases. This method is well suited to probing the longitudinal momentum distributions of 1D gases in situ, and examples are given for bosonic and fermionic atoms.
Lattice Monte Carlo calculations for unitary fermions in a harmonic trap
We present a lattice Monte Carlo approach developed for studying large numbers of strongly interacting nonrelativistic fermions and apply it to a dilute gas of unitary fermions confined to a harmonic trap. In place of importance sampling, our approach makes use of high statistics, an improved action, and recently proposed statistical techniques. We show how improvement of the lattice action can remove discretization and finite volume errors systematically. For N=3 unitary fermions in a box, our errors in the energy scale as the inverse lattice volume, and we reproduce a previous high-precision benchmark calculation to within our 0.3% uncertainty; as additional benchmarks we reproduce precision calculations of N=3,...,6 unitary fermions in a harmonic trap to within our {approx}1% uncertainty. We then use this action to determine the ground-state energies of up to 70 unpolarized fermions trapped in a harmonic potential on a lattice as large as 64{sup 3}x72. In contrast to variational calculations, we find evidence for persistent deviations from the thermodynamic limit for the range of N considered.
Endres, Michael G.; Kaplan, David B.; Lee, Jong-Wan; Nicholson, Amy N. [Physics Department, Columbia University, New York, New York 10027 (United States); Theoretical Research Division, RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1550 (United States)
Highly charged ions in Penning traps, a new tool for resolving low lying isomeric states
The use of highly charged ions increases the precision and resolving power, in particular for short-lived species produced at on-line radio-isotope beam facilities, achievable with Penning trap mass spectrometers. This increase in resolving power provides a new and unique access to resolving low-lying long-lived ($T_{1/2} > 50$ ms) nuclear isomers. Recently, the $111.19(22)$ keV (determined from $\\gamma$-ray spectroscopy) isomeric state in $^{78}$Rb has been resolved from the ground state, in a charge state of $q=8+$ with the TITAN Penning trap at the TRIUMF-ISAC facility. The excitation energy of the isomer was measured to be $108.7(6.4)$ keV above the ground state. The extracted masses for both the ground and isomeric states, and their difference, agree with the AME2003 and Nuclear Data Sheet values. This proof of principle measurement demonstrates the feasibility of using Penning trap mass spectrometers coupled to charge breeders to study nuclear isomers and opens a new route for isomer searches.
A. T. Gallant; M. Brodeur; T. Brunner; U. Chowdhury; S. Ettenauer; V. V. Simon; E. Man�; M. C. Simon; C. Andreoiu; P. Delheij; G. Gwinner; M. R. Pearson; R. Ringle; J. Dilling
Ultrasensitive detection of radioactive cesium isotopes using a magneto-optical trap.
We report the first magneto-optical trapping of mdioactive {sup 135}Cs and {sup 137}Cs and a promising means for detecting these isotopes to ullrasensilive lcvels by a system coupling the magneto-optical trap (MOT) to a mass separator. The mass separator efficiently delivers a 20 kV ion beam of either isotope into a quartzcube MOT cell having in one corner a small-diameter Zr foil, on which the ion beam is focused and into which the ions are implantetl. Inductive heating of thc foil releases {approx}45% of the implanted atoms into a MOT that uses large diameter beams and a dry-film coating to capture 3% of the released vapor. MOT fluorescence signals were found to increasc linearly with the number of foil-implanted atoms over a range of 10{sup 4} to 10{sup 7} in trapped-atom number. The measured slope of MOT signal versus number implanted was equal in the case each isotope to within 4%, signifying our ability to measure {sup 137}Cs/{sup 135}Cs ratios to within 4%. The isotopic selectivities of the mass separator and MOT combine to suppress interfering signal from {sup 133}Cs by a factor of greater than 5 x 10{sup 12} in the case of detecting {sup 135}Cs or {sup 137}Cs. Our present sample detection sensitivity is one million atoms.
Di Rosa, M. D. (Michael D.); Crane, S. G. (Scott G.); Kitten, J. J. (Jason J.); Taylor, W. A. (Wayne A.); Vieira, D. J. (David J.); Zhao, X. (Xinxin)
Visualizing multiphase flow and trapped fluid configurations in a model three-dimensional porous medium
We report an approach to fully visualize the flow of two immiscible fluids through a model three-dimensional (3D) porous medium at pore-scale resolution. Using confocal microscopy, we directly image the drainage of the medium by the non-wetting oil and subsequent imbibition by the wetting fluid. During imbibition, the wetting fluid pinches off threads of oil in the narrow crevices of the medium, forming disconnected oil ganglia. Some of these ganglia remain trapped within the medium. By resolving the full 3D structure of the trapped ganglia, we show that the typical ganglion size, and the total amount of residual oil, decreases as the capillary number Ca increases; this behavior reflects the competition between the viscous pressure in the wetting fluid and the capillary pressure required to force oil through the pores of the medium. This work thus shows how pore-scale fluid dynamics influence the trapped fluid configurations in multiphase flow through 3D porous media.
Krummel, Amber T; M�nster, Stefan; Weitz, David A; 10.1002/aic.14005
Structural evolution of the Permian-Triassic Cooper basin, Australia: Relation to hydrocarbon trap styles
The structural and depositional history of the Cooper basin in eastern central Australia has revealed that the basin is a mildly compressional structural depression controlled by northwestrending and northeast-trending pre-Permian basement features. Pronounced pre-Permian compressions are indicated by northeast-trending major structures, the Gidgealpa-Merrimelia-Innamincka and Murteree-Nappacoongee trends. Detailed chronostratigraphic facies analysis, with closely spaced palynological control, of the Patchawarra Formation revealed that two pronounced phases of uplift occurred during the Sakmarian. The major intrabasin highs were rejuvenated during these tectonic events, as documented by crestal unconformities (middle and upper Patchawarra unconformities). Evidence of each event is dominantly tectonic in character, with similar depositional patterns over these highs related to each event. These events are also recognizable in midflank areas and basin margins with contemporaneous deposition in deeper parts of the basin. Results from this research show potential for future hydrocarbon discoveries within structural, stratigraphic, and structural/stratigraphic traps in the Cooper basin. Various trap styles are closely associated with faults, unconformities, and lateral facies changes. Lowside fault closures, onlap plays, and unconformity traps are expected to be well developed along intrabasinal highs, basin margins, and preexisting structures. The primary reservoir targets would be deltaic sequences comprising shoreline sandstones, distributary and delta-mouth bar deposits that may be well developed in synclinal areas, and flanks of intrabasin highs in the Copper basin.
Apak, S.N. [Geological Survey of Western Australia, East Perth (Australia); Stuart, W.J.; Lemon, N.M. [Univ. of Adelaide (Australia); Wood, G. [Santos Ltd., Adelaide (Australia)
Towards in-situ cleaning of a trapped ion quantum computer
A plasma glow discharge system was created using a conventional microwave oven to ignite and maintain the plasma. The system was used for plasma cleaning and its properties were analysed to assess its viability for removing surface contaminants, which cause anomalous heating, from Paul trap electrodes used in ion trapping. Qualitative results showed that the argon plasma could remove copper oxide layers formed on thin sheets in 1-2 minutes. The addition of air into the plasma system allowed for the cleaning of more complex hydrocarbon contaminants, as highlighted by the removal of permanent marker pen. The surface removal rate of the system was evaluated by measuring the time taken to remove gold plating from washers and aluminium plates. A nominal rate of 5-15 nm per min was found under optimal conditions. Plasma treatment, in addition to wet chemical cleaning, was found to increase the finesse of an optical cavity by a factor of two, compared to acetone cleaning alone. These results are promising for the system's in-situ use on Paul trap electrodes and could be a feasible technique for increasing their lifetime.
Timothy Harrison
Motional heating of ions in micro-fabricated traps is a challenge hindering experimental realization of large-scale quantum processing devices. Recently a series of measurements of the heating rates in surface-electrode ion traps characterized their frequency, distance, and temperature dependencies, but our understanding of the microscopic origin of this noise is still vague. In this work we develop a theoretical model for the electric field noise which is associated with a random distribution of adsorbed atoms on the trap electrode surface. By using first principle calculations of the fluctuating dipole moments of the adsorbed atoms we evaluate the distance, frequency and temperature dependence of the resulting electric field fluctuation spectrum.Our theory calculates the noise spectrum beyond the standard scenario of two-level fluctuators, by incorporating all the relevant vibrational states. The $1/f$ noise is shown to commence at roughly the frequency of the fundamental phonon transition rate and the $d^{-4}$ dependence with distance of the ion from the electrode surface is established.
A. Safavi-Naini; P. Rabl; P. Weck; H. R. Sadeghpour
Amber T. Krummel; Sujit S. Datta; Stefan M�nster; David A. Weitz
Results from a Test Fixture for button BPM Trapped Mode Measurements
A variety of measures have been suggested to mitigate the problem of button BPM trapped mode heating. A test fixture, using a combination of commercial-off-the-shelf and custom machined components, was assembled to validate the simulations. We present details of the fixture design, measurement results, and a comparison of the results with the simulations. A brief history of the trapped mode button heating problem and a set of design rules for BPM button optimization are presented elsewhere in these proceedings. Here we present measurements on a test fixture that was assembled to confirm, if possible, a subset of those rules: (1) Minimize the trapped mode impedance and the resulting power deposited in this mode by the beam. (2) Maximize the power re-radiated back into the beampipe. (3) Maximize electrical conductivity of the outer circumference of the button and minimize conductivity of the inner circumference of the shell, to shift power deposition from the button to the shell. The problem is then how to extract useful and relevant information from S-parameter measurements of the test fixture.
Cameron,P.; Bacha, B.; Blednykh, A.; Pinayev, I.; Singh, O.
Storage of ultracold neutrons in the UCN$?$ magneto-gravitational trap
The UCN$\\tau$ experiment is designed to measure the lifetime $\\tau_{n}$ of the free neutron by trapping ultracold neutrons (UCN) in a magneto-gravitational trap. An asymmetric bowl-shaped NdFeB magnet Halbach array confines low-field-seeking UCN within the apparatus, and a set of electromagnetic coils in a toroidal geometry provide a background "holding" field to eliminate depolarization-induced UCN loss caused by magnetic field nodes. We present a measurement of the storage time $\\tau_{store}$ of the trap by storing UCN for various times, and counting the survivors. The data are consistent with a single exponential decay, and we find $\\tau_{store}=860\\pm19$ s: within $1 \\sigma$ of current global averages for $\\tau_{n}$. The storage time with the holding field deactiveated is found to be $\\tau_{store}=470 \\pm 160$ s; this decreased storage time is due to the loss of UCN which undergo Majorana spin-flips while being stored. We discuss plans to increase the statistical sensitivity of the measurement and investigate potential systematic effects.
D. J. Salvat; E. R. Adamek; D. Barlow; L. J. Broussard; J. D. Bowman; N. B. Callahan; S. M. Clayton; C. Cude-Woods; S. Currie; E. B. Dees; W. Fox; P. Geltenbort; K. P. Hickerson; A. T. Holley; C. -Y. Liu; M. Makela; J. Medina; D. J. Morley; C. L. Morris; S. I. Penttila; J. Ramsey; A. Saunders; S. J. Seestrom; S. K. L. Sjue; B. A. Slaughter; E. I. Sharapov; J. Vanderwerp; B. VornDick; P. L. Walstrom; Z. Wang; T. L. Womack; A. R. Young
Storage of ultracold neutrons in the UCN$\\tau$ magneto-gravitational trap
The UCN$\\tau$ experiment is designed to measure the lifetime $\\tau_{n}$ of the free neutron by trapping ultracold neutrons (UCN) in a magneto-gravitational trap. An asymmetric bowl-shaped NdFeB magnet Halbach array confines low-field-seeking UCN within the apparatus, and a set of electromagnetic coils in a toroidal geometry provide a background "holding" field to eliminate depolarization-induced UCN loss caused by magnetic field nodes. We present a measurement of the storage time $\\tau_{store}$ of the trap by storing UCN for various times, and counting the survivors. The data are consistent with a single exponential decay, and we find $\\tau_{store}=860\\pm19$ s: within $1 \\sigma$ of current global averages for $\\tau_{n}$. The storage time with the holding field deactiveated is found to be $\\tau_{store}=470 \\pm 160$ s; this decreased storage time is due to the loss of UCN which undergo Majorana spin-flips while being stored. We discuss plans to increase the statistical sensitivity of the measurement and investi...
Salvat, D J; Barlow, D; Broussard, L J; Bowman, J D; Callahan, N B; Clayton, S M; Cude-Woods, C; Currie, S; Dees, E B; Fox, W; Hickerson, K P; Holley, A T; Liu, C -Y; Makela, M; Medina, J; Morley, D J; Morris, C L; Penttila, S I; Ramsey, J; Saunders, A; Seestrom, S J; Sjue, S K L; Slaughter, B A; Sharapov, E I; Vanderwerp, J; VornDick, B; Walstrom, P L; Wang, Z; Womack, T L; Young, A R
Coherence of a qubit stored in Zeeman levels of a single optically trapped atom
We experimentally investigate the coherence properties of a qubit stored in the Zeeman substates of the 5S1/2, F=1 hyperfine ground level of a single optically trapped Rb-87 atom. Larmor precession of a single atomic spin-1 system is observed by preparing the atom in a defined initial spin-state and then measuring the resulting state after a programmable period of free evolution. Additionally, by performing quantum state tomography, maximum knowledge about the spin coherence is gathered. By using an active magnetic field stabilization and without application of a magnetic guiding field we achieve transverse and longitudinal dephasing times of T2*=75..150 \\mus and T1>0.5 ms respectively. We derive the light-shift distribution of a single atom in the approximately harmonic potential of a dipole trap and show that the measured atomic spin coherence is limited mainly by residual position- and state-dependent effects in the optical trapping potential. The improved understanding enables longer coherence times, an i...
Rosenfeld, Wenjamin; Weber, Markus; Weinfurter, Harald
We experimentally investigate the coherence properties of a qubit stored in the Zeeman substates of the 5S1/2, F=1 hyperfine ground level of a single optically trapped Rb-87 atom. Larmor precession of a single atomic spin-1 system is observed by preparing the atom in a defined initial spin-state and then measuring the resulting state after a programmable period of free evolution. Additionally, by performing quantum state tomography, maximum knowledge about the spin coherence is gathered. By using an active magnetic field stabilization and without application of a magnetic guiding field we achieve transverse and longitudinal dephasing times of T2*=75..150 \\mus and T1>0.5 ms respectively. We derive the light-shift distribution of a single atom in the approximately harmonic potential of a dipole trap and show that the measured atomic spin coherence is limited mainly by residual position- and state-dependent effects in the optical trapping potential. The improved understanding enables longer coherence times, an important prerequisite for future applications in long-distance quantum communication and computation with atoms in optical lattices or for a loophole-free test of Bell's inequality.
Wenjamin Rosenfeld; J�rgen Volz; Markus Weber; Harald Weinfurter
Integration of Self-Assembled Porous Alumina and Distributed Bragg Reflector for Light Trapping in Si Photovoltaic Devices
Light trapping is an important issue for thin film silicon photovoltaic cells due to the limited absorption coefficient for near infrared light. In this letter, we present a photonic structure that combines porous anodic ...
Experimental investigation of the trapping and energy loss mechanisms of intense relativistic electron rings in hydrogen gas and plasma
This volume is a direct continuation of Volume 1. Included are chapters 5 and 6 which deal with the trapping and confinement of electron rings in preionized media, neutral gases, and plasma.
Smith, A.C. Jr.
The results of an experimental study on the trapping and energy loss mechanisms of intense, relativistic electron rings confined in Astron-like magnetic field geometries are presented. The work is subdivided into four sections: gas trapping; average ring electron energetics; plasma trapping, and hollow-beam cusp-injection into gas and plasma. The mechanisms by which the injected beam coalesces into a current ring in the existing Cornell RECE-Berta facility are considered. To investigate the nature of ring electron energy loss mechanisms following completion of the trapping process, a diagnostic was developed utilizing multi-foil X-ray absorption spectroscopy to analyze the Bremsstrahlung generated by the electrons as they impinge upon a thin tungsten wire target suspended in the circulating current. Finally, a set of preliminary experimental results is presented in which an annular electron beam was passed through a coaxial, non-adiabatic magnetic cusp located at one end of a magnetic mirror well.
Low-cost, deterministic quasi-periodic photonic structures for light trapping in thin film silicon solar cells
Light trapping has been an important issue for thin film silicon solar cells because of the low absorption coefficient in the near infrared range. In this paper, we present a photonic structure which combines anodic aluminum ...
Low cost manufacturing of light trapping features on multi-crystalline silicon solar cells : jet etching method and cost analysis
An experimental study was conducted in order to determine low cost methods to improve the light trapping ability of multi-crystalline solar cells. We focused our work on improving current wet etching methods to achieve the ...
Berrada Sounni, Amine
High-Resolution Imaging and Optical Control of Bose-Einstein Condensates in an Atom Chip Magnetic Trap
A high-resolution projection and imaging system for ultracold atoms is implemented using a compound silicon and glass atom chip. The atom chip is metalized to enable magnetic trapping while glass regions enable high numerical aperture optical access to atoms residing in the magnetic trap about 100 microns below the chip surface. The atom chip serves as a wall of the vacuum system, which enables the use of commercial microscope components for projection and imaging. Holographically generated light patterns are used to optically slice a cigar-shaped magnetic trap into separate regions; this has been used to simultaneously generate up to four Bose-condensates. Using fluorescence techniques we have demonstrated in-trap imaging resolution down to 2.5 microns
Evan A. Salim; Seth C. Caliga; Jonathan B. Pfeiffer; Dana Z. Anderson
A Toy Model of the Instability in the Equatorially Trapped Convectively Coupled Waves on the Equatorial Beta Plane
The equatorial atmospheric variability shows a spectrum of significant peaks in the wavenumber�frequency domain. These peaks have been identified with the equatorially trapped wave modes of rotating shallow water wave theory. This paper addresses ...
Joseph Allan Andersen; Zhiming Kuang
Poly(vinyl alcohol)-based buffering membranes for isoelectric trapping separations
Isoelectric trapping (IET) in multicompartment electrolyzers (MCE) has been widely used for the electrophoretic separation of ampholytic compounds such as proteins. In IET, the separation occurs in the buffering membranes that form a step-wise pH gradient in the MCE. Typically, buffering membranes have been made by copolymerizing acrylamide with Immobiline compounds, which are acidic and basic acylamido buffers. One major problem, however, is that these buffering membranes are not stable when exposed to high concentrations of acid and base due to hydrolysis of the amide bonds. Poly(vinyl alcohol)-based, or PVA-based, membranes were made as an alternative to the polyacrylamide-based membranes since they provide more hydrolytic and mechanical stability. Four mid-pH, PVA-based buffering membranes that contain single ampholytes were synthesized. These buffering membranes were used to trap small molecular weight pI markers for up to three hours, and were also used in desalting experiments to remove strong electrolytes from a solution of ampholytes. Additionally, the membranes were used in IET experiments to separate mixtures of pI markers, and to fractionate the major proteins in chicken egg white. The membranes did not show any degradation when stored in 3 M NaOH for up to 6 months and were shown to tolerate current densities as high as 16 mA/cm2. In addition, six series of PVA-based membranes, whose pH values can be tuned over the 3 < pH < 10 range, were synthesized by covalently binding aminodicarboxylic acids, and monoamines or diamines to the PVA matrix. These tunable buffering membranes were used in trapping experiments to trap ampholytes for up to three hours, and in desalting experiments to remove strong electrolytes from a solution of ampholytes. These tunable buffering membranes were also used in IET experiments to separate proteins, some with pI values that differ by only 0.1 pH unit. The tunable buffering membranes did not show any signs of degradation when exposed to 3 M NaOH for up to 3 months, and could be used in IET experiments with current densities as high as 20 mA/cm2. These tunable buffering membranes are expected to broaden the application areas of isoelectric trapping separations.
Craver, Helen C.
Penning Traps
... due to elastic Rayleigh scattering," Physical Review Letters ... laser-cooled positrons," Nuclear Instruments and Methods in Physics Research B ...
Trapped Inflation
We analyze a distinctive mechanism for inflation in which particle production slows down a scalar field on a steep potential, and show how it descends from angular moduli in string compactifications. The analysis of density perturbations - taking into account the integrated effect of the produced particles and their quantum fluctuations - requires somewhat new techniques that we develop. We then determine the conditions for this effect to produce sixty e-foldings of inflation with the correct amplitude of density perturbations at the Gaussian level, and show that these requirements can be straightforwardly satisfied. Finally, we estimate the amplitude of the non-Gaussianity in the power spectrum and find a significant equilateral contribution.
Green, Daniel; Horn, Bart; /SLAC /Stanford U., Phys. Dept.; Senatore, Leonardo; /Princeton, Inst. Advanced Study /Harvard U., Phys. Dept. /Harvard-Smithsonian Ctr. Astrophys.; Silverstein, Eva; /SLAC /Stanford U., Phys. Dept.
Radionuclide trap
The deposition of radionuclides manganese-54, cobalt-58 and cobalt-60 from liquid sodium coolant is controlled by providing surfaces of nickel or high nickel alloys to extract the radionuclides from the liquid sodium, and by providing surfaces of tungsten, molybdenum or tantalum to prevent or retard radionuclide deposition.
McGuire, Joseph C. (Richland, WA)
Trapped and escaping orbits in an axially symmetric galactic-type potential
In the present article, we investigate the behavior of orbits in a time independent axially symmetric galactic type potential. This dynamical model can be considered to describe the motion in the central parts of a galaxy, for values of energies larger than the energy of escape. We use the classical method of the surface of section, in order to visualize and interpret the structure of the phase space of the dynamical system. Moreover, the Lyapunov Characteristic Exponent (LCE), is used in order to make an estimation of the degree of the chaoticity of the orbits in our galactic model. Our numerical calculations suggest that in this galactic type potential, there are two kinds of orbits: (i) escaping orbits and (ii) trapped orbits which do not escape at all. Furthermore, a large number of orbits of the dynamical system, display chaotic motion. Among the chaotic orbits, there are orbits that escape fast and also orbits that remain trapped for vast time intervals. When the value of the test particle's energy exceeds slightly the energy of escape, the amount of the trapped regular orbits increases, as the the value of the angular momentum increases. Therefore, the extent of the chaotic regions observed in the phase plane decreases as the value of the energy increases. Moreover, we calculate the average value of the escape period of the chaotic orbits and we try to correlate it with the value of the energy and also with the maximum value of the z component of the orbits. In addition, we find that the value of the LCE corresponding to each chaotic region, for different values of the energy, increases exponentially as the value of the energy increases. Some theoretical arguments in order to support the numerically obtained outcomes are presented.
Euaggelos E. Zotos
Trapping and transmission of matter-wave solitons in a collisionally inhomogeneous environment
We investigate bright matter-wave solitons in the presence of a spatially varying scattering length. It is demonstrated that, even in the absence of any external trapping potential, a soliton can be confined due to the inhomogeneous collisional interactions. Moreover we observe the enhanced transmission of matter-wave solitons through potential barriers for suitably chosen spatial variations of the scattering length. The results indicate that the manipulation of atomic interactions can become a versatile tool to control the dynamics of matter waves.
G. Theocharis; P. Schmelcher; P. G. Kevrekidis; D. J. Frantzeskakis
Ground-state properties of trapped Bose-Fermi mixtures: Role of exchange correlation
We introduce density-functional theory for inhomogeneous Bose-Fermi mixtures, derive the associated Kohn-Sham equations, and determine the exchange-correlation energy in local-density approximation. We solve numerically the Kohn-Sham system, and determine the boson and fermion density distributions and the ground-state energy of a trapped, dilute mixture beyond mean-field approximation. The importance of the corrections due to exchange correlation is discussed by a comparison with current experiments; in particular, we investigate the effect of the repulsive potential-energy contribution due to exchange correlation on the stability of the mixture against collapse.
Albus, Alexander P.; Wilkens, Martin [Institut fuer Physik, Universitaet Potsdam, D-14469 Potsdam, (Germany); Illuminati, Fabrizio [Dipartimento di Fisica, Universita di Salerno, and Istituto Nazionale per la Fisica della Materia, I-84081 Baronissi (Saudi Arabia), (Italy)
Prethermalization and dynamical transition in an isolated trapped ion spin chain
We propose an experimental scheme to observe prethermalization and dynamical transition in one-dimensional XY spin chain with long range interaction and inhomogeneous lattice spacing, which can be readily implemented with the recently developed trapped-ion quantum simulator. Local physical observables are found to relax to prethermal values at intermediate time scale, followed by complete relaxation to thermal values at much longer time. The physical origin of prethermalization is explained by spotting a non-trivial structure in lower half of the energy spectrum. The dynamical behavior of the system is shown to cross difference phases when the interaction range is continuously tuned, indicating the existence of dynamical phase transition.
Zhe-Xuan Gong; L. -M. Duan
Dirac Equation and Quantum Relativistic Effects in a Single Trapped Ion
We present a method of simulating the Dirac equation in 3+1 dimensions for a free spin-1/2 particle in a single trapped ion. The Dirac bispinor is represented by four ionic internal states, and position and momentum of the Dirac particle are associated with the respective ionic variables. We show also how to simulate the simplified 1+1 case, requiring the manipulation of only two internal levels and one motional degree of freedom. Moreover, we study relevant quantum-relativistic effects, like the Zitterbewegung and Klein's paradox, the transition from massless to massive fermions, and the relativistic and nonrelativistic limits, via the tuning of controllable experimental parameters.
Lamata, L.; Leon, J. [Instituto de Matematicas y Fisica Fundamental, CSIC, Serrano 113-bis, 28006 Madrid (Spain); Schaetz, T. [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching (Germany); Solano, E. [Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado Postal 1761, Lima (Peru)
High intensity electron beam ion trap for charge state boosting of radioactive ion beams
A high intensity electron beam ion trap under development at LLNL could be adapted for charge state boosting of radioactive ion beams, enabling a substantial reduction in the size and cost of a post-accelerator. We report estimates of the acceptance, ionization time, charge state distribution, emittance, and beam intensity for charge state boosting of radioactive ions in this device. The estimates imply that, for tin isotopes, over 10{sup 10} ions/s can be ionized to q = 40+ with an absolute emittance of approximately 1 (pi) mm mrad at an energy of 30 x q.k.
Marrs, R.
Two-dimensional Vlasov simulation of electron plasma wave trapping, wavefront bowing, self-focusing, and sideloss
Two-dimensional Vlasov simulations of nonlinear electron plasma waves are presented, in which the interplay of linear and nonlinear kinetic effects is evident. The plasma wave is created with an external traveling wave potential with a transverse envelope of width {Delta}y such that thermal electrons transit the wave in a ''sideloss'' time, t{sub sl{approx}{Delta}}y/v{sub e}. Here, v{sub e} is the electron thermal velocity. The quasisteady distribution of trapped electrons and its self-consistent plasma wave are studied after the external field is turned off. In cases of particular interest, the bounce frequency, {omega}{sub be}=k{radical}(e{phi}/m{sub e}), satisfies the trapping condition {omega}{sub be}t{sub sl}>2{pi} such that the wave frequency is nonlinearly downshifted by an amount proportional to the number of trapped electrons. Here, k is the wavenumber of the plasma wave and {phi} is its electric potential. For sufficiently short times, the magnitude of the negative frequency shift is a local function of {phi}. Because the trapping frequency shift is negative, the phase of the wave on axis lags the off-axis phase if the trapping nonlinearity dominates linear wave diffraction. In this case, the phasefronts are curved in a focusing sense. In the opposite limit, the phasefronts are curved in a defocusing sense. Analysis and simulations in which the wave amplitude and transverse width are varied establish criteria for the development of each type of wavefront. The damping and trapped-electron-induced focusing of the finite-amplitude electron plasma wave are also simulated. The damping rate of the field energy of the wave is found to be about the sideloss rate, {nu}{sub e{approx}}t{sub sl}{sup -1}. For large wave amplitudes or widths {Delta}y, a trapping-induced self-focusing of the wave is demonstrated.
Banks, J. W.; Berger, R. L.; Cohen, B. I.; Hittinger, J. A. F. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Brunner, S. [Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)
NOx Reduction with Natural Gas for Lean Large-Bore Engine Applications Using Lean NOx Trap Aftertreatment
Large-bore natural gas engines are used for distributed energy and gas compression since natural gas fuel offers a convenient and reliable fuel source via the natural gas pipeline and distribution infrastructure. Lean engines enable better fuel efficiency and lower operating costs; however, NOx emissions from lean engines are difficult to control. Technologies that reduce NOx in lean exhaust are desired to enable broader use of efficient lean engines. Lean NOx trap catalysts have demonstrated greater than 90% NOx reduction in lean exhaust from engines operating with gasoline, diesel, and natural gas fuels. In addition to the clean nature of the technology, lean NOx traps reduce NOx with the fuel source of the engine thereby eliminating the requirement for storage and handling of secondary fuels or reducing agents. A study of lean NOx trap catalysts for lean natural gas engines is presented here. Testing was performed on a Cummins C8.3G (CG-280) engine on a motor dynamometer. Lean NOx trap catalysts were tested for NOx reduction performance under various engine operating conditions, and the utilization of natural gas as the reductant fuel source was characterized. Engine test results show that temperature greatly affects the catalytic processes involved, specifically methane oxidation and NOx storage on the lean NOx trap. Additional studies on a bench flow reactor demonstrate the effect of precious metal loading (a primary cost factor) on lean NOx trap performance at different temperatures. Results and issues related to the potential of the lean NOx trap technology for large-bore engine applications will be discussed.
Parks, JE
Does The Principle Of Equivalence Prevent Trapped Surfaces From Being Formed In The General Relativistic Collapse Process?
It has been recently shown (Mitra,- astro-ph/9910408, astro-ph/0207056) that the timelike spherical collapse of a radiating, physical fluid in General Relativity, as seen by an interior co-moving observer at rest in the physical fluid, does not permit formation of ``trapped surfaces''. This followed from the fact that the formation of a trapped surface in a physical fluid would cause the timelike world lines of the collapsing fluid to become null at the would be trapped surface, thus violating the Principle of Equivalence in General Theory of Relativity. In this paper we generalize and extend this result by studying the problem from the point of view of the exterior Vaidya metric of a collapsing radiating fluid as seen by an exterior stationary observer, and find that the "no trapped surface condition" becomes g00 > 0 consistent with that obtained for the interior co-moving metric. Since we have shown that the Principle of Equivalence prevents trapped surfaces from being formed in collapsing, radiating objects, then true event horizons cannot exist and Galactic Black Hole Candidates (GBHC) must have physically observable intrinsic magnetic dipole moments. Because of this fact it follows (Robertson and Leiter - astro-ph/0102381, astro-ph/0208333) that GBHC can be consistently described, within the framework of General Relativity, in terms of a magneto-spheric eternally collapsing objects (MECO) without true event horizons.
Darryl Leiter; Stanley Robertson
An Energy Signature Scheme for Steam Trap Assessment and Flow Rate Estimation Using Pipe-Induced Acoustic Measurements
The US Congress has passed legislation dictating that all government agencies establish a plan and process for improving energy efficiencies at their sites. In response to this legislation, Oak Ridge National Laboratory (ORNL) has recently conducted a pilot study to explore the deployment of a wireless sensor system for a real-time measurement-based energy efficiency optimization framework within the steam distribution system within the ORNL campus. We make assessments on the real-time status of the distribution system by observing the state measurements of acoustic sensors mounted on the steam pipes/traps/valves. In this paper, we describe a spectral-based energy signature scheme that interprets acoustic vibration sensor data to estimate steam flow rates and assess steam traps health status. Experimental results show that the energy signature scheme has the potential to identify different steam trap health status and it has sufficient sensitivity to estimate steam flow rate. Moreover, results indicate a nearly quadratic relationship over the test region between the overall energy signature factor and flow rate in the pipe. The analysis based on estimated steam flow and steam trap status helps generate alerts that enable operators and maintenance personnel to take remedial action. The goal is to achieve significant energy-saving in steam lines by monitoring and acting on leaking steam pipes/traps/valves.
Olama, Mohammed M [ORNL; Allgood, Glenn O [ORNL; Kuruganti, Phani Teja [ORNL; Lake, Joe E [ORNL
Integrated Status and Effectiveness Monitoring Program - Entiat River Rotary Screw Traps,Snorkel Surveys, and Steelhead Redd Surveys, 2008.
The USFWS Mid-Columbia River Fishery Resource Office (MCRFRO) operated two rotary screw traps on the Entiat River as part of the Integrated Status and Effectiveness Monitoring Program from March through November of 2008. Along with the smolt traps, juvenile emigrants were also captured at remote locations throughout the Entiat watershed and its major tributary, the Mad River. A total of 16,782 wild salmonids were PIT tagged during the study period. Of this, 3,961(23.6%) were wild Oncorhynchus mykiss, 6,987 (41.6%) were wild spring run O. tshawytscha, and 5,591 (33.3%) were identified as wild O. tshawytscha of unknown run. Rotary screw trap efficiencies averaged 40.3% at the upper (Rkm 11.0) trap and 7.8% for the lower (Rkm 2.0) trap. These efficiencies were pooled for emigrant O. tshawytscha and O. mykiss. The MCRFRO conducted effectiveness monitoring snorkel surveys at 24 sites during the winter period and 30 sites during the summer and fall periods of 2008 as part of the Integrated Status and Effectiveness Monitoring Program in the Entiat River. The 2008 steelhead spawning grounds surveys were conducted weekly in the main Entiat River from rkm 1.1 to 44.2. A total of 222 steelhead redds were identified over the period from February 28 to June 16 2008 with April being the peak spawning month. Approximately 80% of the steelhead redds were located downstream of the rkm 26.
Nelle, R.D.; Desgroseiller, Tom; Cotter, Michael (U.S. Fish and Wildlife Service)
Integrated Status and Effectiveness Monitoring Program - Entiat River Rotary Screw Traps, Snorkel Surveys, and Steelhead Redd Surveys, 2008-2009.
Nelle, R.D.; Desgroseillier, Tom; Cotter, Michael [U.S. Fish and Wildlife Service
EXPERIMENTAL RESULTS ON TRAPPING A GUN PLASMA IN TORMAC P-l
A start-up scheme for producing a plasma in the biscusp field configuration of TORMAC which involves the radial injection and trapping of a toroidal gun plasma is described. The peloidal field of the external cusp coils acts as a barrier to the outward travel of the plasma ring. Interferometry and magnetic probe measurements observed the stopping of the expanding plasma ring which has a velocity of 17 cm/{micro}sec. Once stopped, the fields are arranged to hold the plasma in a magnetic well. Interferometry measurements observed a well defined outer boundary remaining stationary during the 20 {micro}sec of the measurement. The inner boundary was also in evidence as shown particularly by the particle flux distribution emanating from the cusp region. The indications are that a sheath exists having a width of 1 to 1.5 ion gyro radii in the poloidial field. Measurements of Thomson and interferometry give a T{sub e} of 15eV, a 15 {micro}sec density decay time, and a 5 {micro}sec energy decay time. These results show that this injection and trapping method is successful, and thus a higher gun plasma energy combined with a flux conserving barrier may lead to higher temperatures for testing containment in TORMAC.
Pincosy, P.A.; Myers, B.R.; Levine, M.A.; Feinberg, B.; Niland, R.A.; Soroka, L.
The Ramsey method in high-precision mass spectrometry with Penning traps: Experimental results
The highest precision in direct mass measurements is obtained with Penning trap mass spectrometry. Most experiments use the interconversion of the magnetron and cyclotron motional modes of the stored ion due to excitation by external radiofrequency-quadrupole fields. In this work a new excitation scheme, Ramsey's method of time-separated oscillatory fields, has been successfully tested. It has been shown to reduce significantly the uncertainty in the determination of the cyclotron frequency and thus of the ion mass of interest. The theoretical description of the ion motion excited with Ramsey's method in a Penning trap and subsequently the calculation of the resonance line shapes for different excitation times, pulse structures, and detunings of the quadrupole field has been carried out in a quantum mechanical framework and is discussed in detail in the preceding article in this journal by M. Kretzschmar. Here, the new excitation technique has been applied with the ISOLTRAP mass spectrometer at ISOLDE/CERN for mass measurements on stable as well as short-lived nuclides. The experimental resonances are in agreement with the theoretical predictions and a precision gain close to a factor of four was achieved compared to the use of the conventional excitation technique.
S. George; K. Blaum; F. Herfurth; A. Herlert; M. Kretzschmar; S. Nagy; S. Schwarz; L. Schweikhard; C. Yazidjian
Controlled photon emission and Raman transition experiments with a single trapped atom
We present recent results on the coherent control of an optical transition in a single rubidium atom, trapped in an optical tweezer. We excite the atom using resonant light pulses that are short (4 ns) compared with the lifetime of the excited state (26 ns). By varying the intensity of the laser pulses, we can observe an adjustable number of Rabi oscillations, followed by free decay once the light is switched off. To generate the pulses we have developed a novel laser system based on frequency doubling a telecoms laser diode at 1560 nm. By setting the laser intensity to make a pi-pulse, we use this coherent control to make a high quality triggered source of single photons. We obtain an average single photon rate of 9600 s-1 at the detector. Measurements of the second-order temporal correlation function show almost perfect antibunching at zero delay. In addition, we present preliminary results on the use of Raman transitions to couple the two hyperfine levels of the ground state of our trapped atom. This will allow us to prepare and control a qubit formed by two hyperfine sub-levels.
M. P. A. Jones; B. Darquie; J. Beugnon; J. Dingjan; S. Bergamini; Y. Sortais; G. Messin; A. Browaeys; P. Grangier
A very low energy compact electron beam ion trap for spectroscopic research in Shanghai
In this paper, a new compact low energy electron beam ion trap, SH-PermEBIT, is reported. This electron beam ion trap (EBIT) can operate in the electron energy range of 60-5000 eV, with a current density of up to 100 A/cm{sup 2}. The low energy limit of this machine sets the record among the reported works so far. The magnetic field in the central drift tube region of this EBIT is around 0.5 T, produced by permanent magnets and soft iron. The design of this EBIT allows adjustment of the electron gun's axial position in the fringe field of the central magnetic field. This turned out to be very important for optimizing the magnetic field in the region of the electron gun and particularly important for low electron beam energy operation, since the magnetic field strength is not tunable with permanent magnets. In this work, transmission of the electron beam as well as the upper limit of the electron beam width under several conditions are measured. Spectral results from test operation of this EBIT at the electron energies of 60, 315, 2800, and 4100 eV are also reported.
Xiao, J.; Fei, Z.; Yang, Y.; Jin, X.; Lu, D.; Shen, Y.; Hutton, R.; Zou, Y. [The Key lab of Applied Ion Beam Physics, Ministry of Education, Shanghai (China); Shanghai EBIT lab, Institute of Modern Physics, Fudan University, Shanghai (China); Liljeby, L. [Manne Siegbahn Laboratory, Stockholm University, Stockholm (Sweden)
A plasma glow discharge system was created using a conventional microwave oven to ignite and maintain the plasma. The system was used for plasma cleaning and its properties were analysed to assess its viability for removing surface contaminants, which cause anomalous heating, from Paul trap electrodes used in ion trapping. Qualitative results showed that the argon plasma could remove copper oxide layers formed on thin sheets in 1-2 minutes. The addition of air into the plasma system allowed for the cleaning of more complex hydrocarbon contaminants, as highlighted by the removal of permanent marker pen. The surface removal rate of the system was evaluated by measuring the time taken to remove gold plating from washers and aluminium plates. A nominal rate of 5-15 nm per min was found under optimal conditions. Plasma treatment, in addition to wet chemical cleaning, was found to increase the finesse of an optical cavity by a factor of two, compared to acetone cleaning alone. These results are promising for the sy...
Harrison, Timothy
In the present article, we investigate the behavior of orbits in a time independent axially symmetric galactic type potential. This dynamical model can be considered to describe the motion in the central parts of a galaxy, for values of energies larger than the energy of escape. We use the classical method of the surface of section, in order to visualize and interpret the structure of the phase space of the dynamical system. Moreover, the Lyapunov Characteristic Exponent (LCE), is used in order to make an estimation of the degree of the chaoticity of the orbits in our galactic model. Our numerical calculations suggest that in this galactic type potential, there are two kinds of orbits: (i) escaping orbits and (ii) trapped orbits which do not escape at all. Furthermore, a large number of orbits of the dynamical system, display chaotic motion. Among the chaotic orbits, there are orbits that escape fast and also orbits that remain trapped for vast time intervals. When the value of the test particle's energy exce...
Zotos, Euaggelos E
Shell Structure, Melting and Dynamics of Ion Clusters Confined in an Octupolar Trap
The stable structures of clusters of identical ions trapped in an isotropic octupolar trap are investigated using global optimization methods. These clusters form well defined shells of ions that are approximately solutions of the Thomson problem. In particular, magic numbers are found to correlate with highly symmetric configurations. Using Monte Carlo simulations, finite temperature properties are also investigated. Melting proceeds from the core, and takes place through a very progressive loss of the shell structure. The hollow shape is eventually lost at very high temperatures, where the ions essentially feel the confinement but not the Coulomb repulsion. The vibrational density of states shows marked differences with the harmonic case, but also with bulk Wigner crystals. The variations of the maximal Lyapunov exponent obtained from additional molecular dynamics trajectories reveals that the dynamics becomes increasingly chaotic as the temperature increases. With the decreasing influence of the Coulomb interaction, a more regular behavior is found at very high temperatures but, contrary to the quadrupolar case, still highly chaotic.
Calvo, F. [LASIM, Universite Claude Bernard and CNRS, Bat. A. Kastler, 43 Bd du 11 Novembre 1918, F69622 Villeurbanne Cedex (France); Yurtsever, E. [Koc University, Rumelifeneriyolu, Sariyer, Istanbul 34450 (Turkey)
Sequential high temperature reduction, low temperature hydrolysis for the regeneration of sulfated NOx trap catalysts
We describe a new method that minimizes irreversible Pt sintering during the desulfation of sulfated Pt/BaO/Al2O3 lean NOx trap (LNT) catalysts. While it is known that the addition of H2O to H2 promotes desulfation, we find that the significant and irreversible Pt sintering arising from the presence of water is unavoidable. Control of precious metal sintering is considered to be one of the critical issues in the development of durable LNT catalysts. The new method described here is a sequential desulfation process: the first step is to reduce the sulfates with hydrogen only at higher temperatures to form BaS, followed by a treatment of the thus reduced sample with water at low to moderate temperatures to convert BaS to BaO and H2S. The data showed that Pt sintering was significantly inhibited due to the absence of H2O during the desulfation at high temperatures, and also demonstrates the similar NOx uptake with the desulfated sample cooperatively with H2 and H2O. Therefore, the sequential desulfation process may find applications in realistic systems to inhibit the irreversible sintering of the Pt in the lean NOx trap catalyst, leading to a longer catalyst life.
Kim, Do Heui; Kwak, Ja Hun; Wang, Xianqin; Szanyi, Janos; Peden, Charles HF
Trapping the M sub 1 and M sub 2 substrates of bacteriorhodopsin for electron diffraction studies
Visible and Fourier transform infrared (FTIR) absorption spectroscopies are used to observe protein conformational changes occuring during the bacteriorhodopsin photocycle. Spectroscopic measurements which define the conditions under which bacteriorhodopsin can be isolated and trapped in two distinct substates of the m intermediate of the photocycle, M{sub 1}, and M{sub 2}, are described. A protocol that can be used for high-resolution electron diffraction studies is presented that will trap glucose-embedded purple membrane in the M{sub 1}and M{sub 2} substates at greater than 90% concentration. It was discovered that glucose alone does not provide a fully hydrated environment for bacteriorhodopsin. Equilibration of glucose-embedded samples at high humidity can result in a physical state that is demonstrably closer to the native, fully hydrated state. An extension of the C-T Model of bacteriorhodopsin functionality (Fodor et al., 1988; Mathies et al., 1991) is proposed based on FTIR results and guided by published spectra from resonance Raman and FTIR work. 105 refs.
Perkins, G.A.
Electronic properties and deep traps in electron-irradiated n-GaN
The study is concerned with the effect of electron irradiation (with the energies E = 7 and 10 MeV and doses D = 10{sup 16}-10{sup 18} cm{sup -2}) and subsequent heat treatments in the temperature range 100-1000 Degree-Sign C on the electrical properties and the spectrum of deep traps of undoped (concentration of electrons n = 1 Multiplication-Sign 10{sup 14}-1 Multiplication-Sign 10{sup 16} cm{sup -3}), moderately Si-doped (n = (1.2-2) Multiplication-Sign 10{sup 17} cm{sup -3}), and heavily Si-doped (n = (2-3.5) Multiplication-Sign 10{sup 18} cm{sup -3}) epitaxial n-GaN layers grown on Al{sub 2}O{sub 3} substrates by metal-organic chemical vapor deposition. It is found that, on electron irradiation, the resistivity of n-GaN increases, this is due to a shift of the Fermi level to the limiting position close to E{sub c} -0.91 eV. The spectrum of deep traps is studied for the initial and electron-irradiated n-GaN. It is shown that the initial properties of the irradiated material are restored in the temperature range 100-1000 Degree-Sign C, with the main stage of the annealing of radiation defects at about 400 Degree-Sign C.
Brudnyi, V. N., E-mail: firstname.lastname@example.com [Tomsk State University (Russian Federation); Verevkin, S. S. [Karpov Institute of Physical Chemistry (Russian Federation); Govorkov, A. V. [Joint Stock Company 'Federal State Research and Design Institute of Rare Metal Industry (Giredmet)' (Russian Federation); Ermakov, V. S.; Kolin, N. G.; Korulin, A. V. [Karpov Institute of Physical Chemistry (Russian Federation); Polyakov, A. Ya.; Smirnov, N. B. [Joint Stock Company 'Federal State Research and Design Institute of Rare Metal Industry (Giredmet)' (Russian Federation)
Herein, time-dependent scanning Kelvin probe microscopy of solution processed organic thin film transistors (OTFTs) reveals a correlation between film microstructure and OTFT device performance with the location of trapped charge within the device channel. The accumulation of the observed trapped charge is concurrent with the decrease in I{sub SD} during operation (V{sub G}=-40 V, V{sub SD}= -10 V). We discuss the charge trapping and dissipation dynamics as they relate to the film structure and show that application of light quickly dissipates the observed trapped charge.
Teague, L.; Moth, M.; Anthony, J.
Study of Ion Cooling and Ejection from Two Stage Linear Quadrupole Ion Trap consisted of RFQ ion guides
Ion Cooling and Ejection from Two Stage Linear Quadrupole Ion Trap consisted of RFQ ion guides Ion Cooling and Ejection from Two Stage Linear Quadrupole Ion Trap consisted of RFQ ion guides Kozlovskiy V.I., Filatov V. V., Shchepunov (UNIRIB, O.R.A.U. Oak Ridge, TN, USA) V. A., Brusov V. S., Pikhtelev A. R., Zelenov V. V. Introduction The primary objective of this work concerns linear quadrupole ion traps, which are commonly used to interface a continuous ion beam from an external source with a mass analyzer, requiring bunched or pulsed beams. We assume that the ions prepared for mass analysis, are well spatially shaped, and normalized by ion kinetic energy. (Slava, I don't understand the meaning of the previous sentence - I wrote it as I interpreted what you are saying - I may be all wrong) In our work, such a device was developed and built to interface a source of continuous ion beams and a
First Use of High Charge States for Mass Measurements of Short-Lived Nuclides in a Penning Trap
Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed {beta} emitter {sup 74}Rb (T{sub 1/2}=65 ms). The determination of its atomic mass and an improved Q{sub EC} value are presented.
Ettenauer, S.; Gallant, A. T.; Dilling, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Simon, M. C.; Chaudhuri, A.; Mane, E.; Delheij, P.; Pearson, M. R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Brunner, T. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Physik Department E12, Technische Universitaet Muenchen, D-85748 Garching (Germany); Chowdhury, U. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Simon, V. V. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Ruprecht-Karls-Universitaet, Heidelberg (Germany); Brodeur, M. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Andreoiu, C. [Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6 (Canada); Audi, G. [CSNSM-IN2P3-CNRS, Universite Paris 11, 91405 Orsay (France); Lopez-Urrutia, J. R. Crespo; Ullrich, J. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Gwinner, G. [Dept. of Physics and Astronomy, Univ. of Manitoba, Winnipeg, MB R3T 2N2 (Canada); Lapierre, A. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); National Superconducting Cyclotron Lab., Michigan State Univ., East Lansing, Michigan 48824 (United States); Lunney, D. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); CSNSM-IN2P3-CNRS, Univ. Paris 11, 91405 Orsay (France); Ringle, R. [National Superconducting Cyclotron Lab., Michigan State Univ., East Lansing, Michigan 48824 (United States)
Inhibition of the current-driven ion wave instability by electron trapping in the FM-1 spherator
An experimental analysis is made of the scattering of microwaves by the density fluctuations due to the current-driven ion wave instability in a toroidal plasma confinement device, the FM-1 spherator. It is found that the instability exists in the collisional regime and it is inhibited (i.e., quenched by two orders in magnitude) in the trapped-electron (i.e., banana) regime. The inhibition occurs when the electron collision frequency is about equal to the electron bounce frequency between mirror trapping. (auth)
Arunasalam, V.; Okabayaski, M.; Hawryluk, R.J.; Suckewer, S.
Dissipative dynamics of vortex arrays in trapped Bose-condensed gases: neutron stars physics on $?$K scale
We develop a theory of dissipative dynamics of large vortex arrays in trapped Bose-condensed gases. We show that in a static trap the interaction of the vortex array with thermal excitations leads to a non-exponential decay of the vortex structure, and the characteristic lifetime depends on the initial density of vortices. Drawing an analogy with physics of pulsar glitches, we propose an experiment which employs the heating of the thermal cloud in the course of the decay of the vortex array as a tool for a non-destructive study of the vortex dynamics.
P. O. Fedichev; A. E. Muryshev
Cold tolerance of red drum (Sciaenops ocellatus) and thermal-refuge technology to protect this species from cold-kill in aquaculture ponds
The need to protect red drum in aquaculture ponds from cold-kill led to the development of thermalrefuge technology for overwintering these fish. Successive versions of an experimental thermal refuge were installed and operated in two adjacent red drum culture ponds at Redfish Unlimited, Palacios, Texas, during the winters of 1991-92 and 1992-93. Although red drum in the ponds at Palacios were not threatened by cold during either of these mild winters, the thermodynamic efficiency of the two versions of the refuge could be tested and compared, both with each other and with the prototype refuge used in the winter of 1990-91. The 1992-93 refuge design, which featured an inflated, dome-like cover, was the most effective in terms of cost, ease of maintenance, and resistance to heat loss. A mathematical model, based on Newton's law of cooling, was used to simulate refuge thermodynamics. The best-fitting model had exponential rate constants ranging from 0.01 1 to 0.026 min-' for the 1991-92 version and 0.004 to 0.006 min-' for the 1992-93 version (r > 0.99). A second phase of the research focused on cold tolerance of red drum in ponds at Palacios, from 6 February to 2 April 1993. Values of the 24-h lower lethal temperature of fish sampled from refuge-equipped and non-refuge-equipped ponds were estimated via lethal-cold bioassays. Regression of probit-transformed percent survival at 24 h yielded estimates of mean lower lethal temperature which rose from 0.7 IC on 6 February to 6.6 IC on 2 April. Within dates lower lethal temperatures of fish taken from refuge-equipped and non-refugeequipped ponds did not differ; however, there was a significant difference among sample dates. Values of estimated acclimation temperature for these red drum ranged from 13.5 IC on 6 February to 17.7 IC on 2 April. Acclimation temperatures were inferred by exponentially filtering the pondtemperature time series so that the filtered values had maximum linear correlation (r = 0.93) with the lower-lethal-temperature series; the requisite filter had an exponential rate constant of 0.044 day-1.
Dorsett, Paul Wesley
Easy Ways to Save Energy Now Take Care of those Steam Traps
Peter Fuhr Peter Fuhr Wi-Fi Sensors, Inc. Presented by *Easy Ways to Save Energy Now - Take Care of those Steam Traps Together with our industry partners, we strive to: * Accelerate adoption of the many energy-efficient technologies and practices available today * Conduct vigorous technology innovation to radically improve future energy diversity, resource efficiency, and carbon mitigation * Promote a corporate culture of energy efficiency and carbon management What Is the Industrial Technologies Program ? The Industrial Technologies Program (ITP) is the lead federal agency responsible for improving energy efficiency in the largest energy-using sector of the country. Industrial Sector National Initiative Goal: Drive a 25% reduction in industrial energy intensity by 2017.
Diatom Genome Helps Explain Their Great Diversity and Success in Trapping
5, 2008 5, 2008 Diatom Genome Helps Explain Their Great Diversity and Success in Trapping Excess Carbon in Oceans WALNUT CREEK, CA-Diatoms, mighty microscopic algae, have profound influence on climate, producing 20 percent of the oxygen we breathe by capturing atmospheric carbon and in so doing, countering the greenhouse effect. Since their evolutionary origins these photosynthetic wonders have come to acquire advantageous genes from bacterial, animal and plant ancestors enabling them to thrive in today's oceans. These findings, based on the analysis of the latest sequenced diatom genome, Phaeodactylum tricornutum, are published in 15 October edition of the journal Nature by an international team of researchers led by the U.S. Department of Energy Joint Genome Institute (DOE JGI) and the Ecole Normale Supérieure of
Measurement of ground-state decoherence via interruption of coherent population trapping
We examine the role of ground-state coherence on the fluorescence from the excited state in a three-level Lambda system under continuous-wave excitation. When resonantly pumped, the fluorescence is strongly affected by any perturbation in the ground-state coherent population trapping. From our analytical results, we suggest how to use this strong dependence of fluorescence on the ground-state decays as a new method for the measurement of the ground-state decoherence rates. Our calculations should work well for a wide range of systems such as atomic vapors with a buffer gas, active dopants in solids, and quantum dots, etc. We present a proof of principle experiment using Rb-87 vapor.
Patnaik, Anil K.; Hsu, Paul S.; Agarwal, Girish S.; Welch, George R.; Scully, Marlan O.
Dynamics of shallow dark solitons in a trapped gas of impenetrable bosons
The dynamics of linear and nonlinear excitations in a Bose gas in the Tonks-Girardeau regime with longitudinal confinement are studied within a mean-field theory of quintic nonlinearity. A reductive perturbation method is used to demonstrate that the dynamics of shallow dark solitons, in the presence of an external potential, can effectively be described by a variable-coefficient Korteweg-de Vries equation. The soliton oscillation frequency is analytically obtained to be equal to the axial trap frequency, in agreement with numerical predictions obtained by Busch et al. [J. Phys. B 36, 2553 (2003)] via the Bose-Fermi mapping. We obtain analytical expressions for the evolution of both soliton and emitted radiation (sound) profiles.
Frantzeskakis, D.J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 157 84 (Greece); Proukakis, N.P. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515 (United States)
Preparative-scale isoelectric trapping separations in a multicompartmental electrolyzer: implementation and monitoring
Preparative-scale protein separations have always been critical to the advancement of the life sciences. Among preparative-scale separation techniques, isoelectric trapping (IET) promises efficient separations and high production rates. This dissertation focuses on the improvement of two aspects of preparative-scale IET protein separations: the instrumentation used and the monitoring of the separation. The first aspect (preparative-scale) is the IET device: the improvement of a multicompartmental electrolyzer (MCE) to increase the efficiency and production rate of IET separations. The redesign focused on three major areas: (1) the sealing system, (2) the configuration of the liquid flow path, and (3) the cooling system. The second aspect (analytical-scale) is the monitoring of the IET separation: the design and manufacture of durable surface-modified capillaries which provide controlled, variable anodic and cathodic electroosmotic flow (EOF) to help develop, plan, and monitor the IET separations.
Sinajon, Joseph Brian Montejo
Experimental Evidence for a Reduction in Electron Thermal Diffusion due to Trapped Particles
New high time resolution measurements of the electron thermal diffusion {chi}{sub e} throughout the sawtooth cycle of the Madison Symmetric Torus reversed-field pinch have been made by utilizing the enhanced capabilities of the upgraded multipoint, multipulse Thomson scattering system. These measurements are compared to the {chi}{sub e} due to magnetic diffusion predicted by using information from a new high spectral resolution zero-{beta} nonlinear resistive magnetohydrodynamic simulation performed, for the first time, at the Lundquist number of high current Madison Symmetric Torus plasmas (S{approx_equal}4x10{sup 6}). Agreement between the measured and predicted values is found only if the reduction in thermal diffusion due to trapped particles is taken into account.
Reusch, J. A.; Anderson, J. K.; Schnack, D. D. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Den Hartog, D. J.; Ebrahimi, F.; Stephens, H. D.; Forest, C. B. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)