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Office of Scientific and Technical Information
Thermal cracking in disc brakes Thomas J. Mackin *,1
E-Print Network [OSTI]
Thermal cracking in disc brakes Thomas J. Mackin *,1 , Steven C. Noe, K.J. Ball, B.C. Bedell, D, or hub, which is connected to the wheel and axle, and an inboard and outboard braking surface
Salvaggio, Carl
Airborne wear particles railway research group FEM Simulation of train disc brake behavior
1 Airborne wear particles railway research group FEM Simulation of train disc brake behavior a modern train disc brake with brake caliper and high speed pads. During braking, a considerable amount. A model of train brake caliper Aim The overall aim of the MSc degree project is to develop a thermoelastic
Haviland, David
Neutron scattering residual stress measurements on gray cast iron brake discs
SciTech Connect (OSTI)
Neutron diffraction was used to investigate the effects of a heat treatment designed to remove internal residual stresses in brake discs. It is believed that residual stresses may change the rate of deformation of the discs during severe braking conditions when the disc temperature is increased significantly. Neutron diffraction was used to map out residual strain distributions in a production disc before and after a stress-relieving heat treatment. Results from these neutron diffraction experiments show that some residual strains were reduced by as much as 400 microstrain by stress relieving. 5 refs., 5 figs., 1 tab.
Spooner, S.; Payzant, E.A.; Hubbard, C.R. [and others
Integrated vehicle dynamics control via coordination of active front steering and rear braking
Integrated vehicle dynamics control via coordination of active front steering and rear brakingComputer and Automation Research Institue, Hungarian Academy of Sciences, Kende u. 13-17, H-1111, Budapest, Hungary, Email front steering and rear braking in a driver- assist system for vehicle yaw control. The proposed control
Paris-Sud XI, Université de
E-Print Network 3.0 - automotive brake disc Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Please cite this article in press as: F. Massi, et al., Contact surface topography and system dynamics of brake squeal, Wear (2008), Summary: for future work. 487 References 488...
E-Print Network 3.0 - automotive disc brakes Sample Search Results
Storm fronts over galaxy discs: Models of how waves generate extraplanar gas and its anomalous kinematics
The existence of partially ionized, diffuse gas and dust clouds at kiloparsec scale distances above the central planes of edge-on, galaxy discs was an unexpected discovery about 20 yrs ago. Subsequent observations showed that this EDIG (extended or extraplanar diffuse interstellar gas) has rotation velocities approximately 10-20% lower than those in the central plane, and have been hard to account for. Here we present results of hydrodynamic models, with radiative cooling and heating from star formation. We find that in models with star formation generated stochastically across the disc an extraplanar gas layer is generated as long as the star formation is sufficiently strong. However, this gas rotates at nearly the same speed as the mid-plane gas. We then studied a range of models with imposed spiral or bar waves in the disc. EDIG layers were also generated in these models, but primarily over the wave regions, not over the entire disc. Because of this partial coverage, the EDIG clouds move radially, as well as vertically, with the result that observed kinematic anomalies are reproduced. The implication is that the kinematic anomalies are the result of three-dimensional motions when the cylindrical symmetry of the disc is broken. Thus, the kinematic anomalies are the result of bars or strong waves, and more face-on galaxies with such waves should have an asymmetric EDIG component. The models also indicate that the EDIG can contain a significant fraction of cool gas, and that some star formation can be triggered at considerable heights above the disc midplane. We expect all of these effects to be more prominent in young, forming discs, to play a role in rapidly smoothing disc asymmetries, and in working to self-regulate disc structure.
Curtis Struck; Daniel C. Smith
Gravity brake
DOE Patents [OSTI]
A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.
Lujan, Richard E. (Santa Fe, NM)
Braking system
A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling means causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system provides balanced braking forces which can be easily removed and re-established with minimal disturbance to arbor location.
Norgren, D.U.
Magnetic braking of T Tauri stars
We construct models for the rotation rates of T Tauri stars whose spin is regulated by magnetic linkage between the star and a surrounding accretion disc. Our models utilise a time-dependent disc code to follow the accretion process and include the effects of pre-main-sequence stellar evolution. We find that the initial disc mass controls the evolution of the star-disc system. For sufficiently massive discs, a stellar field of $\\sim$ 1 kG is able to regulate the spin rate to the observed values during the classical T Tauri phase. The field then acts to expel the disc and the star spins up at constant angular momentum as a weak-line system. Lower mass discs are ejected at an early epoch and fail to brake the star significantly. We extend the model to close binary systems, and find that the removal of angular momentum from the disc by the secondary significantly prolongs the inner disc lifetime. Such systems should therefore be relatively slow rotators. We also discuss the implications of our model for the spectral energy distributions and variability of T Tauri stars.
P. J. Armitage; C. J. Clarke
Vehicle brake testing system
This invention relates to a force measuring system capable of measuring forces associated with vehicle braking and of evaluating braking performance. The disclosure concerns an invention which comprises a first row of linearly aligned plates, a force bearing surface extending beneath and beside the plates, vertically oriented links and horizontally oriented links connecting each plate to a force bearing surface, a force measuring device in each link, a transducer coupled to each force measuring device, and a computing device coupled to receive an output signal from the transducer indicative of measured force in each force measuring device. The present invention may be used for testing vehicle brake systems.
Stevens, Samuel S. (Harriman, TN); Hodgson, Jeffrey W. (Lenoir City, TN)
Combined hydraulic and regenerative braking system
A combined hydraulic and regenerative braking system and method for an electric vehicle, with the braking system being responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.
Venkataperumal, Rama R. (Troy, MI); Mericle, Gerald E. (Mount Clemens, MI)
Full Hybrid: Braking
Alternative Fuels and Advanced Vehicles Data Center [Office of Energy Efficiency and Renewable Energy (EERE)]
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: Alternative Fuels Data CenterEnergyAuthorization for(EV) Road User AssessmentNREL is aBraking
Regenerative braking device
Disclosed are several embodiments of a regenerative braking device for an automotive vehicle. The device includes a plurality of rubber rollers (24, 26) mounted for rotation between an input shaft (14) connectable to the vehicle drivetrain and an output shaft (16) which is drivingly connected to the input shaft by a variable ratio transmission (20). When the transmission ratio is such that the input shaft rotates faster than the output shaft, the rubber rollers are torsionally stressed to accumulate energy, thereby slowing the vehicle. When the transmission ratio is such that the output shaft rotates faster than the input shaft, the rubber rollers are torsionally relaxed to deliver accumulated energy, thereby accelerating or driving the vehicle.
Hoppie, Lyle O. (Birmingham, MI)
Speciation of Sb in airborne particulate matter, vehicle brake linings, and brake pad wear residues
Speciation of Sb in airborne particulate matter, vehicle brake linings, and brake pad wear residues: XAS XANES EXAFS Antimony Particulate matter Brake linings a b s t r a c t Insights into the speciation of Sb in samples of brake linings, brake pad wear residues, road dust, and atmospheric particulate
Short, Daniel
Variable ratio regenerative braking device
Disclosed is a regenerative braking device (10) for an automotive vehicle. The device includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (36) and an output shaft (42), clutches (38, 46) and brakes (40, 48) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. The rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft is clutched to the transmission while the brake on the output shaft is applied, and are torsionally relaxed to deliver energy to the vehicle when the output shaft is clutched to the transmission while the brake on the input shaft is applied. The transmission ratio is varied to control the rate of energy accumulation and delivery for a given rotational speed of the vehicle drivetrain.
Commercial Motor Vehicle Brake Assessment Tools
Commercial Motor Vehicle Brake Assessment Tools Commercial Motor Vehicle Roadside Technology to deceleration in g's Passing score: BE43.5 · Enforcement tool for only 3 years. · Based solely on brake Brake Research · CMVRTC research built on these enforcement tools Correlation Study Level-1 / PBBT
Brake blending strategy for a hybrid vehicle
A hybrid electric powertrain system is provided including a transmission for driving a pair of wheels of a vehicle and a heat engine and an electric motor/generator coupled to the transmission. A friction brake system is provided for applying a braking torque to said vehicle. A controller unit generates control signals to the electric motor/generator and the friction brake system for controllably braking the vehicle in response to a drivers brake command. The controller unit determines and amount of regenerative torque available and compares this value to a determined amount of brake torque requested for determining the control signals to the electric motor/generator and the friction brake system.
Boberg, Evan S. (Hazel Park, MI)
Disturbance Control of the Hydraulic Brake in a Wind Turbine
Disturbance Control of the Hydraulic Brake in a Wind Turbine Frank Jepsen, Anders Søborg brake in a wind turbine. Brake torque is determined by friction coefficient and clamp force; the latter brake is one1 of the two independent brake systems in a wind turbine. As a consequence of the gearing
Yang, Zhenyu
TMV Technology Capabilities Brake Stroke Monitor
TMV Technology Capabilities Brake Stroke Monitor Brake monitoring systems are proactive maintenance This technology allows for CMV operators to have knowledge of their steer, drive, and tandem axle group weights setup is required. Current Safety/Enforcement Technologies EOBR (electronic on-board recorder) On
Turbine disc sealing assembly
A disc seal assembly for use in a turbine engine. The disc seal assembly includes a plurality of outwardly extending sealing flange members that define a plurality of fluid pockets. The sealing flange members define a labyrinth flow path therebetween to limit leakage between a hot gas path and a disc cavity in the turbine engine.
Diakunchak, Ihor S.
Contactless magnetic brake for automotive applications
consumption due to power assistance, and requirement for anti-lock controls. To solve these problems, a contactless magnetic brake has been developed. This concept includes a novel flux-shunting structure to control the excitation flux generated by permanent...
Gay, Sebastien Emmanuel
Brake Defect Causation and Abatement Study (BDCAS)
Brake Defect Causation and Abatement Study (BDCAS) Oak Ridge National Laboratory managed by UT corrective actions and validate true abatement of initial out-of- service causation the FMCSA began the BDCAS
Adaptive controller for regenerative and friction braking system
A regenerative and friction braking system for a vehicle having one or more road wheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the road wheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the road wheels of the vehicle without skidding or slipping will not be exceeded. 8 figs.
Davis, R.I.
A regenerative and friction braking system for a vehicle having one or more roadwheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the roadwheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the roadwheels of the vehicle without skidding or slipping will not be exceeded.
Davis, Roy I. (Ypsilanti, MI)
Electric vehicle regenerative antiskid braking and traction control system
An antiskid braking and traction control system for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes one or more sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensors and determining if regenerative antiskid braking control, requiring hydrualic braking control, or requiring traction control are required. The processor then employs a control strategy based on the determined vehicle state and provides command signals to a motor controller to control the operation of the electric traction motor and to a brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative antiskid braking control, hydraulic braking control, and traction control.
Cikanek, Susan R. (Wixom, MI)
An antiskid braking and traction control system for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes one or more sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensors and determining if regenerative antiskid braking control, requiring hydraulic braking control, or requiring traction control are required. The processor then employs a control strategy based on the determined vehicle state and provides command signals to a motor controller to control the operation of the electric traction motor and to a brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative antiskid braking control, hydraulic braking control, and traction control. 10 figs.
Cikanek, S.R.
Why Brake-By-Wire (BBW) ? Advantages of BBW
Conventional Brake System http://www.conti-online.com #12;BBW Survey [ SKF (Motor + PGT +Ball Screw)] [ DELPHI (Motor + PGT +Ball Screw)] [Continental Teves (Motor + PGT + Roller Screw)] [Continental Teves installed at wheel] #12;Sectional Drawing of the Electromechanically Actuated Disk Brake From ITT Brake Pads Caliper
Yao, Bin
The effect of friction on drum brakes
The boundary element method (BEM) has been developed for a long period of time. Cruse and Wilson developed an isoparametric quadratic element. Rizzo, Cruse, Rizzo and Shippy, and Swedlow and cruse applied the method to various problems. It shows that the BEM can provide a very good analytical result in the linear problem and it can reduce time in preparation of numerical data. Watson and Newcomb pointed out that the pressure distribution on the contact surface of the brake drum and the lining plate do not vary significantly along the axis. The deflection can be reduced by an appropriate design of the web; therefore, two dimensional analysis with the BEM is used in this analysis. Based on the authors` knowledge, this is the first paper to analyze the drum brake by using the BEM. The assumptions are the brake drum to be a rigid body, perfect interface contact between the drum and the shoe, the constant friction coefficient of the friction material and the thermal effect to be neglected. The two dimensional equations are derived based on the Somigliana`s identity. Since there is no shape function and no need of the Jacobin for the coordinate transform, to integrate numerically is easier and to write a computer code is simpler for the constant value element than the second order element. The linear element is inappropriate to treat the comer problem. Using the linear elements or second order elements creates discontinuous phenomena along the irregular boundary. The common nodal point has different normal vector and boundary conditions. It is necessary to have an extra equation to provide a unique solution for the final linear equation. Using the constant value element can get rid of this problem. The effect of the friction on the pressure distribution at the friction interface is studied. The calculated results of the pressure distribution are compared with the available data. The mathematical model can be used as a design tool to predict the performance of drum brakes.
Huang, Y.M.; Shyr, J.S. [National Taiwan Univ. (China)
E-Print Network 3.0 - antiskid braking system Sample Search Results
and Idar Petersen2 Summary: -lock brake systems ABS control the brake torque of each wheel to prevent it from getting locked... in the process of braking. This is important to...
Pulsar Braking Index and Mass Accretion
I show that the braking index, $N$, a fundamental pulsar experimental quantity, naturally differs from the canonical value of 3 by terms which involve mass accretion. Using the measured values of $N$ for PSR1509-58 and PSR0531+21, I determine that for constant density neutron stars their present mass accretion rates are $(3.10\\pm.51)\\times10^{-5}$ M year$^{-1}$ and $(9.946\\pm.089)\\times10^{-5}$ M year$^{-1}$ respectively, where M is the mass of each pulsar. Finally, I demonstrate that mass accretion removes the outstanding problem of the origin of the big glitches of the Vela Pulsar.
P. D. Morley
Do Si stars undergo any magnetic braking?
The old question of rotational braking of Ap Si stars is revisited on the empirical side, taking advantage of the recent Hipparcos results. Field stars with various evolutionary states are considered, and it is shown that the loose correlation between their rotational period and their surface gravity is entirely compatible with conservation of angular momentum. No evidence is found for any loss of angular momentum on the Main Sequence, which confirms earlier results based on less reliable estimates of surface gravity. The importance of reliable, fundamental Teff determinations of Bp and Ap stars is emphasized.
P. North
E-Print Network 3.0 - antilock brake systems Sample Search Results
such as trucks, tractor... -trailers and buses. In these brake systems, compressed air is used as the energy transmitting medium to actuate... the foundation brakes mounted...
E-Print Network 3.0 - anti-lock braking system Sample Search...
A diagnostic system for air brakes in commercial vehicles
to maintenance and hence they require frequent inspections. Current inspection techniques require an inspector to go underneath a vehicle to check the brake system for possible faults, such as leaks, worn brake pads, out-of-adjustment of push rods, etc...
Coimbatore Subramanian, Shankar Ram
Development of Diagnostic Algorithms for Air Brakes in Trucks
causes a reduction in the steady-state pressure in the brake chamber and an increase in the lag of the braking pressure response thereby increasing the stopping distance of the vehicle. Currently a presence of leak in the system is detected...
Dhar, Sandeep
A pressure control scheme for air brakes in commercial vehicles
This research is focused on developing a control scheme for regulating the pressure in the brake chamber of an air brake system found in most commercial vehicles like trucks, tractor-trailers and buses. Such a control scheme can be used...
Bowlin, Christopher Leland
Braking system for use with an arbor of a microscope
A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling device causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system provides balanced braking forces which can be easily removed and re-established with minimal disturbance to arbor location.
Norgren, Duane U. (Orinda, CA)
Front Burner- Issue 15
Broader source: Energy.gov [DOE]
The Cybersecurity Front Burner Issue No. 15 addresses the DOE eSCRM Program and Secure Online Shopping.
Enclosed rotary disc air pulser
An enclosed rotary disc air pulser for use with a solvent extraction pulse olumn includes a housing having inlet, exhaust and pulse leg ports, a shaft mounted in the housing and adapted for axial rotation therein, first and second disc members secured to the shaft within the housing in spaced relation to each other to define a chamber therebetween, the chamber being in communication with the pulse leg port, the first disc member located adjacent the inlet port, the second disc member being located adjacent the exhaust port, each disc member having a milled out portion, the disc members positioned on the shaft so that as the shaft rotates, the milled out portions permit alternative cyclical communication between the inlet port and the chamber and the exhaust port and the chamber.
Olson, A. L. (Idaho Falls, ID); Batcheller, Tom A. (Idaho Falls, ID); Rindfleisch, J. A. (Arco, ID); Morgan, John M. (Arco, ID)
Regenerative braking on bicycles to power LED safety flashers
This work develops a method for capturing some of the kinetic energy ordinarily lost during braking on bicycles to power LED safety flashers. The system is designed to eliminate: (a) battery changing in popular LED flashers, ...
Collier, Ian M
Asbestos-free brake-lining materials for hydrogenerators
Three different asbestos-free materials currently considered as new lining materials for hydrogenerator brakes were tested and compared to the original asbestos lining. Results show that these substitutes not only vary greatly from the original material in terms of mechanical properties and physical characteristics but also exhibit significantly different performances in braking tests. Consequently, these new materials are not entirely suitable for the intended application.
Lalonde, S.; Lanteigne, J. [Hydro-Quebec, Varennes, Quebec (Canada)
Investigation of aerodynamic braking devices for wind turbine applications
This report documents the selection and preliminary design of a new aerodynamic braking system for use on the stall-regulated AWT-26/27 wind turbines. The goal was to identify and design a configuration that offered improvements over the existing tip brake used by Advanced Wind Turbines, Inc. (AWT). Although the design objectives and approach of this report are specific to aerodynamic braking of AWT-26/27 turbines, many of the issues addressed in this work are applicable to a wider class of turbines. The performance trends and design choices presented in this report should be of general use to wind turbine designers who are considering alternative aerodynamic braking methods. A literature search was combined with preliminary work on device sizing, loads and mechanical design. Candidate configurations were assessed on their potential for benefits in the areas of cost, weight, aerodynamic noise, reliability and performance under icing conditions. As a result, two configurations were identified for further study: the {open_quotes}spoiler-flap{close_quotes} and the {open_quotes}flip-tip.{close_quotes} Wind tunnel experiments were conducted at Wichita State University to evaluate the performance of the candidate aerodynamic brakes on an airfoil section representative of the AWT-26/27 blades. The wind tunnel data were used to predict the braking effectiveness and deployment characteristics of the candidate devices for a wide range of design parameters. The evaluation was iterative, with mechanical design and structural analysis being conducted in parallel with the braking performance studies. The preliminary estimate of the spoiler-flap system cost was $150 less than the production AWT-26/27 tip vanes. This represents a reduction of approximately 5 % in the cost of the aerodynamic braking system. In view of the preliminary nature of the design, it would be prudent to plan for contingencies in both cost and weight.
Griffin, D.A. [R. Lynette & Associates, Seattle, WA (United States)
Influence of physical parameters and operating conditions for structural integrity of mechanical system subjected to squeal noise
for the static load and circular wave front lines for the ramp loading. Introduction Disc brake systems-linear vibrations, acoustic radiation, brake squeal, friction Abstract. This work proposes to study the effects of physical parameters and loading conditions on both dynamic and acoustic responses of a brake system
Paris-Sud XI, Universit� de
Regenerative braking device with rotationally mounted energy storage means
A regenerative braking device for an automotive vehicle includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (30) and an output shaft (32), clutches (50, 56) and brakes (52, 58) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. In a second embodiment the clutches and brakes are dispensed with and the variable ratio transmission is connected directly across the input and output shafts. In both embodiments the rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft rotates faster or relative to the output shaft and are torsionally relaxed to deliver energy to the vehicle when the output shaft rotates faster or relative to the input shaft.
Fuzzy logic electric vehicle regenerative antiskid braking and traction control system
An regenerative antiskid braking and traction control system using fuzzy logic for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensor and determining if regenerative antiskid braking control, requiring hydraulic braking control, and requiring traction control are required. The processor then employs fuzzy logic based on the determined vehicle state and provides command signals to a motor controller to control operation of the electric traction motor and to the brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative braking control, hydraulic braking control, and traction control. 123 figs.
Evaluation of driver braking performance to an unexpected object in the roadway
components, specifically whether the equation accurately reflects driver and vehicle behaviors during a braking maneuver. This research evaluated the two components of the SSD equation. Four field studies were conducted that evaluated driver braking...
Picha, Dale Louis
Control Engineering Practice 11 (2003) 163170 A mechatronic conception of a new intelligent braking system
, residual friction, noise, vibrations, a new brake has been designed according to a modular principle which describes a new intelligent braking system for motor vehicles. A mechatronic approach helped to avoid some
An regenerative antiskid braking and traction control system using fuzzy logic for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensor and determining if regenerative antiskid braking control, requiring hydraulic braking control, and requiring traction control are required. The processor then employs fuzzy logic based on the determined vehicle state and provides command signals to a motor controller to control operation of the electric traction motor and to the brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative braking control, hydraulic braking control, and traction control.
Evaluation of Corrosion Failure in Tractor-Trailer Brake System
As reported to ORNL, concomitant with the introduction of different deicing and anti-icing compounds, there was an increase in the brake failure rate of tractor-trailer trucks. A forensic evaluation of a failed brake system was performed. Optical and scanning electron microscopic evaluation showed corrosion to be mostly confined to the brake table/lining interface. The corrosion is non-uniform as is to be expected for plain carbon steel in chloride environments. This initial analysis found no evidence for the chlorides of calcium and magnesium, which are the newly introduced deicing and antiicing compounds and are less soluble in water than the identified chlorides of sodium and potassium, in the scale. The result could be as a result of non-exposure of the examined brake table to calcium and magnesium chloride. The mechanisms for the increased failure rate are postulated as being an increased rate of corrosion due to positive shifts in the corrosion potential, and an increased amount of corrosion due to an increased ''time of wetness'' that results from the presence of hygroscopic salts. Laboratory scale evaluation of the corrosion of plain carbon steel in simulated deicing and anti-icing solutions need to be performed to determine corrosion rates and morphological development of corrosion product, to compare laboratory data to in-service data, and to rank economically feasible replacement materials for low carbon steel. In addition, the mechanical behavior of the lining attached to the brake shoe table needs to be assessed. It is opined that an appropriate adjustment of materials could easily allow for a doubling of a brake table/lining lifetime. Suggestions for additional work, to clarify the mechanisms of rust jacking and to develop possible solutions, are described.
Wilson, DF
E-Print Network 3.0 - air brake association Sample Search Results
... Source: Southwest Region University Transportation Center Collection: Engineering ; Energy Storage, Conversion and Utilization 2 Commercial Motor Vehicle Brake Assessment...
Airbus A320 Braking as Predicate-Action Peter B. Ladkin
Airbus A320 Braking as Predicate-Action Diagrams Peter B. Ladkin Universit�at Bielefeld, Technische of the Airbus A320 braking systems contained in the Flight Crew Operating Manual. This helps identify to interest us and others in the design of the A320 braking system [FI.93a, FI.93b, FI.93c]. This paper
Ladkin, Peter B.
Adaptive Rollover Prevention for Automotive Vehicles with Differential Braking
Adaptive Rollover Prevention for Automotive Vehicles with Differential Braking Selim Solmaz, switching, and tuning (MMST) paradigm [13, 14, 15] for preventing untripped rollover in automotive vehicles performance than its fixed robust counterpart. Keywords: Automotive control; Multiple models; Parameter
Duffy, Ken
Many applications require brakes, for instance to decelerate or to
an error occurs in the process of a robotic arm. The energy consumption and actuation force of these brakes is very high. A team of TU Delft scientists developed a method to reduce the energy consumption. The energy consumption is high because an actuator has to generate a normal force between two friction
Oxygen-Diffused Titanium as a Candidate Brake Rotor Material
Titanium alloys are one of several candidate materials for the next generation of truck disk brake rotors. Despite their advantages of lightweight relative to cast iron and good strength and corrosion resistance, titanium alloys are unlikely to be satisfactory brake rotor materials unless their friction and wear behavior can be significantly improved. In this study, a surface engineering process oxygen diffusion was applied to titanium rotors and has shown very encouraging results. The oxygen diffused Ti-6Al-4V (OD-Ti) was tested on a sub-scale brake tester against a flat block of commercial brake lining material and benchmarked against several other Ti-based materials, including untreated Ti-6Al-4V, ceramic particle-reinforced Ti composites (MMCs), and a thermal-spray-coated Ti alloy. With respect to friction, the OD-Ti outperformed all other candidate materials under the imposed test conditions with the friction coefficient remaining within a desirable range of 0.35-0.50, even under the harshest conditions when the disk surface temperature reached nearly 600 ?C. In addition, the OD-Ti showed significantly improved wear-resistance over the non-treated one and was even better than the Ti-based composite materials.
Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Jolly, Brian C [ORNL
aircraft brake materials: Topics by E-print Network
brake materials First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 26 REDUCTION OF CADMTUM PLATING ON...
Braking index of isolated pulsars: open questions and ways forward
Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate, the commonly accepted view is that it arises either through emission of magnetic dipole radiation (MDR) from a rotating magnetized body, through emission of a relativistic particle wind, or via higher order magnetic multipole or gravitational quadrupole radiation. The calculated energy loss by a rotating pulsar is model dependent and leads to the power law $\\dot{\\Omega}$ = -K $\\Omega^{\\rm n}$ where $n$ is called the braking index. The theoretical value for braking index is $n = 1, 3, 5$ for wind, MDR, quadrupole radiation respectively. The accepted view is that pulsar braking is strongly dominated by MDR. Highly precise observations of isolated pulsars yield braking index values in the range $1 < n < 2.8$ which are consistently less than the value pred...
Hamil, Oliver
. Szab´o*, J. Bokor*, C. Poussot-Vassal**, O. Sename**, L. Dugard** *Computer and Automation Research active suspensions and an active brake is proposed to improve the safety of vehicles. The design is based of the method is demonstrated through a complex simulation example containing vehicle maneuvers. Keywords: LPV
Computer animation via optical video disc
This paper explores the notion of marrying two technologies: raster-scan computer animation and optical video discs. Animated sequences, generated at non real-time rates, then transfered to video disc, can be recalled under ...
Bender, Walter
A simulation model of focus and radial servos in Compact Disc players with Disc surface defects
A simulation model of focus and radial servos in Compact Disc players with Disc surface defects P of controllers handling surface defects easier. A simulation model of Compact Disc players playing discs of the controller has been based on trial and error on real test systems since no simulation models of the defects
Wickerhauser, M. Victor
Heavy and Overweight Vehicle Brake Testing: Five-Axle Combination Tractor-Flatbed Final Report
The Federal Motor Carrier Safety Administration, in coordination with the Federal Highway Administration, sponsored the Heavy and Overweight Vehicle Brake Testing (HOVBT) program in order to provide information about the effect of gross vehicle weight (GVW) on braking performance. Because the Federal Motor Carrier Safety Regulations limit the number of braking system defects that may exist for a vehicle to be allowed to operate on the roadways, the examination of the effect of brake defects on brake performance for increased loads is also relevant. The HOVBT program seeks to provide relevant information to policy makers responsible for establishing load limits, beginning with providing test data for a combination tractor/trailer. This testing was conducted on a five-axle combination vehicle with tractor brakes meeting the Reduced Stopping Distance requirement rulemaking. This report provides a summary of the testing activities, the results of various analyses of the data, and recommendations for future research. Following a complete brake rebuild, instrumentation, and brake burnish, stopping tests were performed from 20 and 40 mph with various brake application pressures (15 psi, 25 psi, 35 psi, 45 psi, 55 psi, and full system pressure). These tests were conducted for various brake conditions at the following GVWs: 60,000, 80,000, 91,000, 97,000, 106,000, and 116,000 lb. The 80,000-lb GVWs included both balanced and unbalanced loads. The condition of the braking system was also varied. To introduce these defects, brakes (none, forward drive axle, or rear trailer axle) were made inoperative. In addition to the stopping tests, performance-based brake tests were conducted for the various loading and brake conditions. Analysis of the stopping test data showed the stopping distance to increase with load (as expected) and also showed that more braking force was generated by the drive axle brakes than the trailer axle brakes. The constant-pressure stopping test data revealed a linear relationship between brake application pressure and was used to develop an algorithm to normalize stopping data for weight and initial speed.
Lascurain, Mary Beth [ORNL; Capps, Gary J [ORNL; Franzese, Oscar [ORNL
Energy Efficiency in Heavy Vehicle Tires, Drivetrains, and Braking Systems
This document was prepared to support the primary goals of the Department of Energy, Office of Heavy Vehicle Technologies. These were recently stated as follows: ''Develop by 2004 the enabling technologies for a class 7-8 truck with a fuel efficiency of 10 mpg (at 65 mph) which will meet prevailing emission standards. For Class 3-6 trucks operating on an urban driving cycle, develop by 2004 commercially viable vehicles that achieve at least double the fuel economy of comparable current vehicles (1999), and as a research goal, reduce criteria pollutants to 30% below EPA standards. Develop by 2004 the diesel engine enabling technologies to support large-scale industry dieselization of Class 1 and 2 trucks, achieving a 35 % fuel efficiency improvement over comparable gasoline-fueled trucks, while meeting applicable emissions standards.'' The enabling technologies for improving the fuel efficiency of trucks, include not only engine technologies but also technologies involved with lowering the rolling resistance of tires, reducing vehicle aerodynamic drag, improving thermal management, and reducing parasitic frictional losses in drive train components. Opportunities also exist for making better use of the energy that might ordinarily be dissipated during vehicle braking. Braking systems must be included in this evaluation since safety in truck operations is vital, and braking requirements are greater for vehicles having lowered resistance to rolling. The Office of Heavy Vehicle Technologies has initiated a program to improve the aerodynamics of heavy vehicles through wind tunnel testing, computational modeling, and on-road evaluations. That activity is described in a separate multi-year plan; therefore, emphasis in this document will be on tires, drive trains, and braking systems. Recent, dramatic fluctuations in diesel fuel prices have emphasized the importance of effecting savings in truck fuel economy by implementing new component designs and materials.
Peter J. Blau
Dark Matter in Disc Galaxies
Recent work on the mass distribution in spiral galaxies, using mainly HI observations, is reviewed. The principal problem is still to determine to what extent the dark matter is important in the inner parts of a galaxy, or in other words, how dominant is the self-gravitation of the disc. Studies of the shapes of rotation curves show that in detail there is sufficient individuality in spiral galaxies to prohibit the construction of ``Universal Rotation Curves''. A detailed account is given of the method of Athanassoula et al. (1987), where swing amplifier criteria are applied to set a range in the mass-to-light ratio of the disc. To restrict this range further, other methods might be useful. For a number of bright spirals the rotation curve drops just outside the optical image, but this feature by itself cannot constrain unambiguously the mass models. The use of velocity dispersions seems a promising way, though the observational problems are hard. Within the uncertainties, discs can be close to ``maximum'', even though a range of values cannot be excluded.
A. Bosma
Thin, thick and dark discs in LCDM
In a LCDM cosmology, the Milky Way accretes satellites into the stellar disc. We use cosmological simulations to assess the frequency of near disc plane and higher inclination accretion events, and collisionless simulations of satellite mergers to quantify the final state of the accreted material and the effect on the thin disc. On average, a Milky Way-sized galaxy has 3 subhalos with vmax>80km/s; 7 with vmax>60km/s; and 15 with vmax>40km/s merge at redshift z>1. Assuming isotropic accretion, a third of these merge at an impact angle 20 degrees) are twice as likely as low inclination ones. These lead to structures that closely resemble the recently discovered inner/outer stellar halos. They also do more damage to the Milky Way stellar disc creating a more pronounced flare, and warp; both long-lived and consistent with current observations. The most massive mergers (vmax>80km/s) heat the thin disc enough to produce a thick disc. These heated thin disc stars are essential for obtaining a thick disc as massive as that seen in the Milky Way; they likely comprise some ~50-90% of the thick disc stars. The Milky Way thin disc must reform from fresh gas after z=1 [abridged].
J. I. Read; G. Lake; O. Agertz; Victor P. Debattista
E-Print Network 3.0 - automotive drum brakes Sample Search Results
Biochemistry, Georgia Institute of Technology Collection: Chemistry 3 Commercial Motor Vehicle Brake Assessment Tools Summary: System Visual determination of potentially unsafe...
E-Print Network 3.0 - air brakes Sample Search Results
... Source: Oak Ridge National Laboratory, Center for Transportation Analysis Collection: Energy Storage, Conversion and Utilization 2 CMV Brake Wear and Performance Test Little is...
E-Print Network 3.0 - automotive brake materials Sample Search...
such as trucks, tractor... -trailers and buses. In these brake systems, compressed air is used as the energy transmitting medium to ... Source: Southwest Region University...
The Roles of Discs for Planetary Systems
It is known that the discs are detected for some of the extra-solar planetary systems. It is also likely that there was a disc mixing with planets and small bodies while our Solar System was forming. From our recent results, we conclude that the discs play two roles: the gravity makes planetary systems more chaotic and the drag makes planetary systems more resonant.
Li-Chin Yeh; Ing-Guey Jiang
AB-Net Method of Protection from Projectiles (city, military base, battle-front, etc.)
The author suggests a low cost special AB-Net from artificial fiber, which may protect cities and important objects from rockets, artillery and mortar shells, projectiles, bullets, and strategic weapons. The idea is as follows: The offered AB-Net joins an incoming projectile to a small braking parachute and this incoming projectile loses speed by air braking after a drag distance of 50 - 150 meters. A following interception net after the first may serve to collect the slowed projectiles and their fragments or bomblets so that they do not reach the aimpoint. The author offers the design of AB-Net, a developed theory of snagging with a small braking parachute by AB-Net; and sample computations. These nets may be used for defense of a town, city, military base, battle-front line, road (from terrorists), or any important objects or installations (for example nuclear electric station, government buildings, etc.). Computed projects are: Net to counter small rockets (for example, from Qassam), net to counter artillery projectile (caliber 76 mm), net to counter bullets (caliber 7.6 mm). The offered method is cheaper by thousands of times than protection of a city by current anti-rocket systems. Discussion and results are at the end of the article. Key words: Protection from missile and projectile weapons, mortar, rocket, AB-Net, Qassam defense, incoming defense, armor.
Alexander Bolonkin
accretion disc 2d: Topics by E-print Network
of a dwarf novae disc through its outburst cycle, from isolating the spectrum of a disc wind to revealing the geometry of disc spiral shocks. I end with an outline of the future...
accretion disc structure: Topics by E-print Network
Plant and Environment Interactions Arsenic Accumulation in the Hyperaccumulator Chinese Brake and Its Utilization
in a greenhouse. At recently, however, has Chinese brake (Pteris vittata L.)harvest, the Chinese brake produced soils (0.477.56 mg As kg 1 ),concentration to water-soluble arsenic in soil) of 1450 and a transloca to remediate arsenic contaminated soils. schullat, 2000), soil arsenic concentration (Jiang and Singh, 1994
Ma, Lena
Vehicle yaw control via coordinated use of steering/braking systems
Vehicle yaw control via coordinated use of steering/braking systems M. Doumiati, O. Sename, firstname.lastname@example.com) Computer and Automation Research Institute, Hungarian Academy of Sciences, Kende u. 13-17, H-1111, Budapest with steer- ing/braking coordination task for vehicle yaw control. For steerability enhancement, only active
Modeling the pneumatic relay valve of an s-cam air brake
- niques. The design of a model-based diagnostic system requires the development and experimental corroboration of a mathematical model of the evolution of pressure in each brake chamber of a truck in response to the application of brake pedal input...
Vilayannur Natarajan, Shankar
Modeling the pneumatic subsystem of a S-cam air brake system
The air brake system is one of the critical components in ensuring the safe operation of any commercial vehicle. This work is directed towards the development of a fault-free model of the pneumatic subsystem of the air brake system. This model can...
Coimbatore Subramanian, Shankar
Fault tolerant control of automatically controlled vehicles in response to brake system failures
in the brake system is vital. In this thesis, nonlinear failure detection filters are used for fault detection of sensors and actuators in a class of nonlinear systems. In this thesis, the effects of brake system failures in an AHS where the vehicle steering...
Hsien, Li-Wei
Emission Factor for Antimony in Brake Abrasion Dusts as One of the
originating from automobiles. Abrasion dusts from commercially available brake pads (nonasbestos organic type factors originating from automobiles were approximately 32 µg Sb/braking/car for PM10 and 22 µg Sb of automobiles to the atmospheric Sb concen- tration. The emission factors of pollutants from automobiles have
artificial disc replacement: Topics by E-print Network
in three-dimensional discs CERN Preprints Summary: Vortex formation through the Rossby wave instability (RWI) in protoplanetary discs has been invoked to play a role in planet...
artificial cervical disc: Topics by E-print Network
Wind turbine trailing-edge aerodynamic brake design
This report describes the design of a centrifugally actuated aerodynamic-overspeed device for a horizontal-axis wind turbine. The device will meet the following criteria; (1) It will be effective for airfoil angles of attack 0{degrees} to 45{degrees}. (2) It will be stowed inside the blade profile prior to deployment. (3) It will be capable of offsetting the positive torque produced by the overall blade. (4) Hinge moments will be minimized to lower actuator loads and cost. (5) It will be evaluated as a potential power modulating active rotor-control system. A literature review of aerodynamic braking devices was conducted. Information from the literature review was used to conceptualize the most effective devices for subsequent testing and design. Wind-tunnel test data for several braking devices are presented in this report. Using the data for the most promising configuration, a preliminary design was developed for a MICON 65/13 wind turbine with Phoenix 7.9-m rotor blades.
Quandt, G.
Front Burner - Issue 18 | Department of Energy
Energy Savers [EERE]
Front Burner - Issue 18 Front Burner - Issue 18 The Cybersecurity Front Burner Issue No. 18 addresses keeping kids safe on the Internet, cyber crime, and DOE Cyber awareness and...
Front Burner - Issue 13 | Department of Energy
Broader source: Energy.gov (indexed) [DOE]
3 Front Burner - Issue 13 The Cybersecurity Front Burner Issue No. 13 contained a message from the Associate Chief Information Officer (ACIO) for Cybersecurity informing readers...
Front Burner - Issue 14 | Department of Energy
4 Front Burner - Issue 14 The Cybersecurity Front Burner Issue No. 14 addresses the 2013 National Cybersecurity Awareness Month (NCSAM) Campaign and Phishing Scams. Cybersecurity...
Preliminary survey report: control technology for brake lining at Northwest Local School District, Cincinnati, Ohio
A walk-through survey of control technology for reducing asbestos exposure during maintenance and repair of vehicular brakes was conducted at Northwest Local School District, Cincinnati, Ohio in January, 1986. The primary method for controlling and collecting dust during brake servicing was a wet-washing technique and good work practices, ensuring that exposure to hazardous physical or chemical agents was reduced or eliminated. Also available was an enclosed-type brake assembly cleaner designed to be connected to the shop air and a vacuum system. The brake assembly cleaner did not have a viewing port to examine the area being cleaned. The operator had to remove the unit to inspect the cleaned area potentially exposing himself to any dust remaining on the brake shoes or hub. The unit itself was a potential dust source as it was designed to fit 16-inch wheels and did not form a tight seal on the smaller 15-inch wheels of the newer buses. The authors conclude that the wet wash technique is an excellent method for controlling asbestos emissions during brake maintenance. The vacuum brake-assembly cleaner is inadequate and potentially hazardous. An in-depth survey of the wet technique is recommended.
Cooper, T.C.; McGlothlin, J.D.; Godbey, F.W.; Sheehy, J.W.; O'Brien, D.M.
Photoevaporation of protoplanetary discs I: hydrodynamic models
In this paper we consider the effect of the direct ionizing stellar radiation field on the evolution of protoplanetary discs subject to photoevaporative winds. We suggest that models which combine viscous evolution with photoevaporation of the disc (e.g. Clarke, Gendrin & Sotomayor 2001) incorrectly neglect the direct field after the inner disc has drained, at late times in the evolution. We construct models of the photoevaporative wind produced by the direct field, first using simple analytic arguments and later using detailed numerical hydrodynamics. We find that the wind produced by the direct field at late times is much larger than has previously been assumed, and we show that the mass-loss rate scales as $R_{in}^{1/2}$ (where $R_{in}$ is the radius of the instantaneous inner disc edge). We suggest that this result has important consequences for theories of disc evolution, and go on to consider the effects of this result on disc evolution in detail in a companion paper (Alexander, Clarke & Pringle 2006b).
R. D. Alexander; C. J. Clarke; J. E. Pringle
The Disc-Jet Connection
A large body of theoretical and computational work shows that jets - modelled as magnetized disk winds - exert an external torque on their underlying disks that can efficiently remove angular momentum and act as major drivers of disk accretion. These predictions have recently been confirmed in direct HST measurements of the jet rotation and angular momentum transport in low mass protostellar systems. We review the theory of disc winds and show that their physics is universal and scales to jets from both low and high mass star forming regions. This explains the observed properties of outflows in massive star forming regions, before the central massive star generates an ultracompact HII region. We also discuss the recent numerical studies on the formation of massive accretion disks and outflows through gravitational collapse, including our own work on 3D Adaptive Mesh simulations (using the FLASH code) of the hydromagnetic collapse of an initial rotating, and cooling Bonner-Ebert sphere. Magnetized collapse gives rise to outflows. Our own simulations show that both a jet-like disk wind on sub AU scales, and a larger scale molecular outflow occur (Banerjee and Pudritz 2005).
Ralph E. Pudritz; Robi Banerjee
Achieving Consistent Maximum Brake Torque with Varied Injection Timing in a DI Diesel Engine
, the characteristics of combustion for swept injection timings along the maximum brake torque plateau are determined. The research is conducted by varying injection timing at constant engine speed and load while measuring engine emissions and in-cylinder pressure...
Kroeger, Timothy H
Slug pellet spreading: the double-disc performances available with a single disc spreader
1 Slug pellet spreading: the double-disc performances available with a single disc spreader D for slug pellets application. The principal aim of this paper is to show the chosen way to reach spreading pellets 1 Introduction In France, slugs are considered as a harmful destroyer for crops. Their activities
A mathematical model for air brake systems in the presence of leaks
A MATHEMATICAL MODEL FOR AIR BRAKE SYSTEMS IN THE PRESENCE OF LEAKS A Thesis by SRIVATSAN RAMARATHNAM Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... August 2008 Major Subject: Mechanical Engineering A MATHEMATICAL MODEL FOR AIR BRAKE SYSTEMS IN THE PRESENCE OF LEAKS A Thesis by SRIVATSAN RAMARATHNAM Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...
Ramaratham, Srivatsan
The Evolution of Stellar Exponential Discs
Models of disc galaxies which invoke viscosity-driven radial flows have long been known to provide a natural explanation for the origin of stellar exponential discs, under the assumption that the star formation and viscous timescales are comparable. We present models which invoke simultaneous star formation, viscous redistribution of gas and cosmologically-motivated gaseous infall and explore the predictions such models make for the scale length evolution and radial star formation history of galactic stellar discs. While the inclusion of viscous flows is essential for ensuring that the stellar disc is always exponential over a significant range in radius, we find that such flows play essentially no role in determining the evolution of the disc scale length. In models in which the main infall phase precedes the onset of star formation and viscous evolution, we find the exponential scale length to be rather invariant with time. On the other hand, models in which star formation/viscous evolution and infall occur concurrently result in a smoothly increasing scale length with time, reflecting the mean angular momentum of material which has fallen in at any given epoch. The disc stellar populations in these models are predominantly young (ie. ages < 5 Gyr) beyond a few scale lengths. In both cases, viscous flows are entirely responsible for transporting material to very large radii. We discuss existing observational constraints on these models from studies of both local and moderate redshift disc galaxies. In particular, a good agreement is found between the solar neighbourhood star formation history predicted by our infall model and the recent observational determination of this quantity by Rocha-Pinto et al (2000).
Annette Ferguson; Cathie Clarke
Braking index of isolated uniformly rotating magnetized pulsars
Isolated pulsars are rotating neutron stars with accurately measured angular velocities $\\Omega$, and their time derivatives which show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of debate in detail, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of $\\Omega$. This relation leads to the power law $\\dot{\\Omega}$ = -K $\\Omega^{\\rm n}$ where $n$ is called the braking index. The MDR model predicts $n$ exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of $n$, individually accurate to a few percent or better, in the range 1$ <$ n $ < $ 2.8, which is consi...
Hamil, Oliver; Urbanec, Martin; Urbancova, Gabriela
Satellites in Discs: Regulating the Accretion Luminosity
We demonstrate, using a simple analytic model, that the presence of a massive satellite can globally modify the structure and emission properties of an accretion disc to which it is tidally coupled. We show, using two levels of numerical approximation, that the analytic model gives reasonable results. The results are applicable to two astrophysical situations. In the case of an active galactic nucleus, we consider the case of a $\\sim 10^3\\Msun$ compact companion to the central black-hole and show that it could modulate the emitted spectrum on a timescale of $\\sim10^5$ years. In the case of a T Tauri accretion disc, a satellite such as a sub-dwarf or giant planet could modify the disc spectral energy distribution over a substantial fraction of the T Tauri star lifetime.
Dave Syer; Cathie Clarke
accretion discs due: Topics by E-print Network
the hole. Such a break in the disc may be significant in systems where we know the inclination of the outer accretion disc to the line of sight, such as some X-ray binaries: the...
accretion discs formed: Topics by E-print Network
accretion discs induced: Topics by E-print Network
and the rotational energy of the accreted matter is carried out by a magnetized wind outflowing from the disc. The outflow of matter from the disc occurs due to the...
accretion disc particle: Topics by E-print Network
accretion disc dynamo: Topics by E-print Network
Magnesium Front End Design and Development
by: Alan A. Luo and R. C. McCune Presented by: James Quinn, General Motors Unibody Architecture 3-piece Mg front end (bodyframe) USAMP AMD 603 - Magnesium Front End Design and...
Front Burner - Issue 16 | Department of Energy
6 Front Burner - Issue 16 The Cybersecurity Front Burner Issue No. 16 addresses Malware, the Worst Passwords of 2013, and the Flat Stanley and Stop.Think.Connect. Campaign....
3-DIMENSIONAL COMPACT DISC (CD) MICROFLUIDIC PLATFORM Presented to the
3-DIMENSIONAL COMPACT DISC (CD) MICROFLUIDIC PLATFORM _______________ A Thesis Presented OF THE THESIS 3-Dimensional Compact Disc (CD) Microfluidic Platform by Nitin Edmund Harwood Master of Science in a compact disc (CD) microfluidics platform involving two or more layers. The traditional 2-Dimensional
Kassegne, Samuel Kinde
Disc valve for sampling erosive process streams
This is a patent for a disc-type, four-port sampling valve for service with erosive high temperature process streams. Inserts and liners of ..cap alpha..-silicon carbide respectively, in the faceplates and in the sampling cavities, limit erosion while providing lubricity for a smooth and precise operation. 1 fig.
Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.
Preliminary survey report: evaluation of brake-drum service controls at Pennsylvania Bureau of Vehicle Management, Vehicle Maintenance Division, Harrisburg, Pennsylvania
Exposure to asbestos during the servicing of brakes on state-owned vehicles at the Bureau of Vehicle Management Maintenance Division, Harrisburg, Pennsylvania, was investigated as part of a study of control technologies. Brakes had been serviced at this garage facility for the previous year using a BCE-1000 Clayton brake-cleaning unit, sized for cars, vans, and pickups. The brake-cleaning unit consisted of a transparent enclosure hood and a HEPA vacuum filter dust collector, designed to contain and collect all brake-lining dust during vehicular brake maintenance and replacement. The authors conclude that the Clayton BCE-1000 dust-control unit appeared to be effective in containing and collecting brake dust during all vehicular brake maintenance and replacement jobs in this situation.
Van Wagenen, H.D.
Accretion Disc Evolution in Single and Binary T Tauri Stars
We present theoretical models for the evolution of T Tauri stars surrounded by circumstellar discs. The models include the effects of pre-main-sequence stellar and time dependent disc evolution, and incorporate the effects of stellar magnetic fields acting on the inner disc. For single stars, consistency with observations in Taurus-Auriga demands that disc dispersal occurs rapidly, on much less than the viscous timescale of the disc, at roughly the epoch when heating by stellar radiation first dominates over internal viscous dissipation. Applying the models to close binaries, we find that because the initial conditions for discs in binaries are uncertain, studies of extreme mass ratio systems are required to provide a stringent test of theoretical disc evolution models. We also note that no correlation of the infra-red colours of T Tauri stars with their rotation rate is observed, in apparent contradiction to the predictions of simple magnetospheric accretion models.
Philip J. Armitage; C. J. Clarke; C. A. Tout
On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering
On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering, linear dampers for haptic rendering using a prototype haptic device outfitted with eddy current brakes discuss the results from haptic experiments for rendering viscosity, virtual walls and virtual friction
Hayward, Vincent
REPORT on the TRUCK BRAKE LINING WORKSHOP and FLEET OPERATORS' SURVEY
The report summarizes what transpired during brake linings-related workshop held at the Fall 2003 meeting of the Technology and Maintenance Council (TMC) in Charlotte, NC. The title of the workshop was ''Developing a Useful Friction Material Rating System''. It was organized by a team consisting of Peter Blau (Oak Ridge National Laboratory), Jim Britell (National Highway Traffic Safety Administration), and Jim Lawrence (Motor and Equipment Manufacturers Association). The workshop was held under the auspices of TMC Task Force S6 (Chassis), chaired by Joseph Stianche (Sanderson Farms, Inc.). Six invited speakers during the morning session provided varied perspectives on testing and rating aftermarket automotive and truck brake linings. They were: James R. Clark, Chief Engineer, Foundation Brakes and Wheel Equipment, Dana Corporation, Spicer Heavy Axle and Brake Division; Charles W. Greening, Jr, President, Greening Test Labs; Tim Duncan, General Manager, Link Testing Services;Dennis J. McNichol, President, Dennis NationaLease; Jim Fajerski, Business Manager, OE Sales and Applications Engineering, Federal Mogul Corporation; and Peter J. Blau, Senior Materials Development Engineer, Oak Ridge National Laboratory. The afternoon break-out sessions addressed nine questions concerning such issues as: ''Should the federal government regulate aftermarket lining quality?''; ''How many operators use RP 628, and if so, what's good or bad about it?''; and ''Would there be any value to you of a vocation-specific rating system?'' The opinions of each discussion group, consisting of 7-9 participants, were reported and consolidated in summary findings on each question. Some questions produced a greater degree of agreement than others. In general, the industry seems eager for more information that would allow those who are responsible for maintaining truck brakes to make better, more informed choices on aftermarket linings. A written fleet operator survey was also conducted during the TMC meeting. Twenty-one responses were received, spanning fleet sizes between 12 and 170,000 vehicles. Responses are summarized in a series of tables separated into responses from small (100 or fewer powered vehicles), medium (101-1000 vehicles), and large fleets (>1000 vehicles). The vast majority of fleets do their own brake maintenance, relying primarily on experience and lining manufactures to select aftermarket linings. At least half of the responders are familiar to some extent with TMC Recommended Practice 628 on brake linings, but most do not use this source of test data as the sole criterion to select linings. Significant shortfalls in the applicability of TMC RP 628 to certain types of brake systems were noted.
Blau, P.J.
Recycled brake linings as partial aggregate substitute in asphalt paving. Construction and final report. Report for July 1992-August 1996
The purpose of this project was to evaluate the performance of asphalt containing various percentages of brake lining as an aggregate, and compare its performance to that of normal asphalt containing natural aggregate. This project is an effort to explore alternate ways to use waste product. Four test section of FB-2 Modified mix containing brake lining materials were placed in July 1992 along with one control section on SR 3022 in Mercer county. To date all sections are performing satisfactory, and Brake linings should be recommended as a viable partial replacement of aggregate in bituminous materials. This study only considered the performance of only off-spec brake linings, therefore, any performance data or enviromental effects of placement of used brake material should be addressed.
Miller, P.A.; Sukley, R.
The Photoevaporation of Discs Around Young Stars in Massive Clusters
We present models in which the photoevaporation of discs around young stars by an external ultraviolet source (as computed by Adams et al 2004) is coupled with the internal viscous evolution of the discs. These models are applied to the case of the Orion Nebula Cluster, where the presence of a strong ultraviolet field from the central OB stars, together with a detailed census of circumstellar discs and photoevaporative flows, is well established. In particular we investigate the constraints that are placed on the initial disc properties in the ONC by the twin requirement that most stars possess a disc on a scale of a few A.U., but that only a minority ($ 0.1 M_\\odot$). The ubiquity of discs on a small scale, on the other hand, mainly constrains the timespan over which the discs have been exposed to the ultraviolet field ($< 2 $Myr). We argue that the discs that are resolved by HST represent a population of discs in which self-gravity was important at the time that the dominant central OB star switched on, but that, according to our models, self-gravity is unlikely to be important in these discs at the present time. We discuss the implications of our results for the so-called proplyd lifetime problem.
C. J. Clarke
Real-Time Dynamic Brake Assessment Conduct a proof-of-concept
Real-Time Dynamic Brake Assessment Purpose Conduct a proof-of-concept test to examine the Federal Motor Carrier Safety Administration's Vehicle and Roadside Operations Division Concept stemming conducted for the National Highway Transportation Safety Administration. Signals to be collected Real
Regenerative Braking for an Electric Vehicle Using Ultracapacitors and a Buck-Boost Converter
Regenerative Braking for an Electric Vehicle Using Ultracapacitors and a Buck-Boost Converter Juan for an Electric Vehicle has been simulated. The purpose of this device is to allow higher accelerations, similar in shape and size to a Chevrolet S-10. This vehicle was already converted to an electric car
Catholic University of Chile (Universidad Cat�lica de Chile)
A study of factors affecting foot movement time in a braking maneuver
The nature of foot movement time (MT) in an actual braking maneuver and in a stationary vehicle was investigated regarding the effects of age and gender of the driver and nature of the stimulus to which the driver was responding. ANOVAs showed...
Berman, Andrea Helene
[NeII] emission line profiles from photoevaporative disc winds
I model profiles of the [NeII] forbidden emission line at 12.81um, emitted by photoevaporative winds from discs around young, solar-mass stars. The predicted line luminosities (~ 1E-6 Lsun) are consistent with recent data, and the line profiles vary significantly with disc inclination. Edge-on discs show broad (30-40km/s) double-peaked profiles, due to the rotation of the disc, while in face-on discs the structure of the wind results in a narrower line (~10km/s) and a significant blue-shift (5-10km/s). These results suggest that observations of [NeII] line profiles can provide a direct test of models of protoplanetary disc photoevaporation.
R. D. Alexander
Light-Front Holographic QCD
The relation between the hadronic short-distance constituent quark and gluon particle limit and the long-range confining domain is yet one of the most challenging aspects of particle physics due to the strong coupling nature of Quantum Chromodynamics, the fundamental theory of the strong interactions. The central question is how one can compute hadronic properties from first principles; i.e., directly from the QCD Lagrangian. The most successful theoretical approach thus far has been to quantize QCD on discrete lattices in Euclidean space-time. Lattice numerical results follow from computation of frame-dependent moments of distributions in Euclidean space and dynamical observables in Minkowski spacetime, such as the time-like hadronic form factors, are not amenable to Euclidean lattice computations. The Dyson-Schwinger methods have led to many important insights, such as the infrared fixed point behavior of the strong coupling constant, but in practice, the analyses are limited to ladder approximation in Landau gauge. Baryon spectroscopy and the excitation dynamics of nucleon resonances encoded in the nucleon transition form factors can provide fundamental insight into the strong-coupling dynamics of QCD. New theoretical tools are thus of primary interest for the interpretation of the results expected at the new mass scale and kinematic regions accessible to the JLab 12 GeV Upgrade Project. The AdS/CFT correspondence between gravity or string theory on a higher-dimensional anti-de Sitter (AdS) space and conformal field theories in physical space-time has led to a semiclassical approximation for strongly-coupled QCD, which provides physical insights into its nonperturbative dynamics. The correspondence is holographic in the sense that it determines a duality between theories in different number of space-time dimensions. This geometric approach leads in fact to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian 'Light-Front Holography'. Light-Front Holography is in fact one of the most remarkable features of the AdS/CFT correspondence. The Hamiltonian equation of motion in the light-front (LF) is frame independent and has a structure similar to eigenmode equations in AdS space. This makes a direct connection of QCD with AdS/CFT methods possible. Remarkably, the AdS equations correspond to the kinetic energy terms of the partons inside a hadron, whereas the interaction terms build confinement and correspond to the truncation of AdS space in an effective dual gravity approximation. One can also study the gauge/gravity duality starting from the bound-state structure of hadrons in QCD quantized in the light-front. The LF Lorentz-invariant Hamiltonian equation for the relativistic bound-state system is P{sub {mu}}P{sup {mu}}|{psi}(P)> = (P{sup +}P{sup -} - P{sub {perpendicular}}{sup 2})|{psi}(P)> = M{sup 2}|{psi}(P)>, P{sup {+-}} = P{sup 0} {+-} P{sup 3}, where the LF time evolution operator P{sup -} is determined canonically from the QCD Lagrangian. To a first semiclassical approximation, where quantum loops and quark masses are not included, this leads to a LF Hamiltonian equation which describes the bound-state dynamics of light hadrons in terms of an invariant impact variable {zeta} which measures the separation of the partons within the hadron at equal light-front time {tau} = x{sup 0} + x{sup 3}. This allows us to identify the holographic variable z in AdS space with an impact variable {zeta}. The resulting Lorentz-invariant Schroedinger equation for general spin incorporates color confinement and is systematically improvable. Light-front holographic methods were originally introduced by matching the electromagnetic current matrix elements in AdS space with the corresponding expression using LF theory in physical space time. It was also shown that one obtains identical holographic mapping using the matrix elements of the energy-momentum tensor by perturbing the AdS metric around its static solution. A gravity dual to QCD is not known, but th
Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.
Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load
Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of /sup 3/H/sub 2/O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the /sup 3/H/sub 2/O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc.
Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.
Self-regulated gravitational accretion in protostellar discs
We present a numerical model for the evolution of a protostellar disc that has formed self-consistently from the collapse of a molecular cloud core. The global evolution of the disc is followed for several million years after its formation. The capture of a wide range of spatial and temporal scales is made possible by use of the thin-disc approximation. We focus on the role of gravitational torques in transporting mass inward and angular momentum outward during different evolutionary phases of a protostellar disc with disc-to-star mass ratio of order 0.1. In the early phase, when the infall of matter from the surrounding envelope is substantial, mass is transported inward by the gravitational torques from spiral arms that are a manifestation of the envelope-induced gravitational instability in the disc. In the late phase, when the gas reservoir of the envelope is depleted, the distinct spiral structure is replaced by ongoing irregular nonaxisymmetric density perturbations. The amplitude of these density perturbations decreases with time, though this process is moderated by swing amplification aided by the existence of the disc's sharp outer edge. Our global modelling of the protostellar disc reveals that there is typically a residual nonzero gravitational torque from these density perturbations, i.e. their effects do not exactly cancel out in each region. In particular, the net gravitational torque in the inner disc tends to be negative during first several million years of the evolution, while the outer disc has a net positive gravitational torque. Our global model of a self-consistently formed disc shows that it is also self-regulated in the late phase, so that it is near the Toomre stability limit, with a near-uniform Toomre parameter Q\\approx 1.5-2.0. (Abstract abridged).
E. I. Vorobyov; S. Basu
accretion discs non-barotropic: Topics by E-print Network
Far-infrared and sub-millimetre surveys of circumstellar discs.�
. This thesis focuses on observational studies at far-infrared and sub-millimetre wavelengths of debris discs and the late stages of protoplanetary disc evolution. An overview of surveys for debris discs performed to date is presented, highlighting...
Phillips, Neil Matthew
Light front Casimir effect at finite temperature
The correct description of the standard Casimir effect for periodic boundary conditions via light front formalism implies in these conditions imposed at fixed Minkowski times [Almeida {\\it et al.} Phys. Rev. {\\bf D 87}, 065028 (2013); Chabysheva and Hiller, Phys. Rev. {\\bf D 88}, 085006 (2013)] instead of fixed light front times. The unphysical nature of this latter condition is manifested in the vacuum part by no regularization yielding a finite Casimir energy density [Lenz and Steinbacher, Phys. Rev. {\\bf D 67}, 045010 (2003)]. In the present paper, we extend this discussion and analyze the problem of the light front quantization with simultaneous presence of a thermal bath and boundary conditions. Considering both the oblique light front as well as Dirac light front coordinates, we show that the imposition of periodic boundary conditions at fixed Minkowski times recovers the expected behaviors for the energy density and Casimir entropy. We also investigate how the unphysical nature of the periodic boundary...
Rodrigues, P L M; Alves, Danilo T; Alves, Van S�rgio; Silva, Charles R
Secular evolution of viscous and self-gravitating circumstellar discs
We add the effect of turbulent viscosity via the \\alpha-prescription to models of the self-consistent formation and evolution of protostellar discs. Our models are non-axisymmetric and carried out using the thin-disc approximation. Self-gravity plays an important role in the early evolution of a disc, and the later evolution is determined by the relative importance of gravitational and viscous torques. In the absence of viscous torques, a protostellar disc evolves into a self-regulated state with disk-averaged Toomre parameter Q \\sim 1.5-2.0, non-axisymmetric structure diminishing with time, and maximum disc-to-star mass ratio \\xi = 0.14. We estimate an effective viscosity parameter \\alpha_eff associated with gravitational torques at the inner boundary of our simulation to be in the range 10^{-4}-10^{-3} during the late evolution. Addition of viscous torques with a low value \\alpha = 10^{-4} has little effect on the evolution, structure, and accretion properties of the disc, and the self-regulated state is largely preserved. A sequence of increasing values of \\alpha results in the discs becoming more axisymmetric in structure, being more gravitationally stable, having greater accretion rates, larger sizes, shorter lifetimes, and lower disc-to-star mass ratios. For \\alpha=10^{-2}, the model is viscous-dominated and the self-regulated state largely disappears by late times. (Abridged)
E. I. Vorobyov; Shantanu Basu
Nonlinear analysis of time series of vibration data from a friction brake: SSA, PCA, and MFDFA
We use the methodology of singular spectrum analysis (SSA), principal component analysis (PCA), and multi-fractal detrended fluctuation analysis (MFDFA), for investigating characteristics of vibration time series data from a friction brake. SSA and PCA are used to study the long time-scale characteristics of the time series. MFDFA is applied for investigating all time scales up to the smallest recorded one. It turns out that the majority of the long time-scale dynamics, that is presumably dominated by the structural dynamics of the brake system, is dominated by very few active dimensions only and can well be understood in terms of low dimensional chaotic attractors. The multi-fractal analysis shows that the fast dynamical processes originating in the friction interface are in turn truly multi-scale in nature.
Nikolay K. Vitanov; Norbert P. Hoffmann; Boris Wernitz
Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. In the simplest case of a laminar (non-turbulent) core with the magnetic field aligned with the rotation axis, both analytic considerations and numerical simulations have shown that the formation of a large, 10{sup 2} AU scale, rotationally supported protostellar disk is suppressed by magnetic braking in the ideal MHD limit for a realistic level of core magnetization. This theoretical difficulty in forming protostellar disks is termed the ''magnetic braking catastrophe''. A possible resolution to this problem, proposed by Hennebelle and Ciardi and Joos et al., is that misalignment between the magnetic field and rotation axis may weaken the magnetic braking enough to enable disk formation. We evaluate this possibility quantitatively through numerical simulations. We confirm the basic result of Joos et al. that the misalignment is indeed conducive to disk formation. In relatively weakly magnetized cores with dimensionless mass-to-flux ratio {approx}> 4, it enabled the formation of rotationally supported disks that would otherwise be suppressed if the magnetic field and rotation axis are aligned. For more strongly magnetized cores, disk formation remains suppressed, however, even for the maximum tilt angle of 90 Degree-Sign . If dense cores are as strongly magnetized as indicated by OH Zeeman observations (with a mean dimensionless mass-to-flux ratio {approx}2), it would be difficult for the misalignment alone to enable disk formation in the majority of them. We conclude that, while beneficial to disk formation, especially for the relatively weak field case, misalignment does not completely solve the problem of catastrophic magnetic braking in general.
Li Zhiyun [Astronomy Department, University of Virginia, Charlottesville, VA (United States); Krasnopolsky, Ruben; Shang, Hsien [Academia Sinica, Theoretical Institute for Advanced Research in Astrophysics, Taipei, Taiwan (China)
Variations in gear fatigue life for different wind turbine braking strategies
A large number of gearbox failures have occurred in the wind industry in a relatively short period, many because service loads were underestimated. High-torque transients that occur during starting and stopping are difficult to predict and may be overlooked in specifying gearbox design. Although these events comprise a small portion of total load cycles, they can be the most damaging. The severity of these loads varies dramatically with the specific configuration of the wind turbine. The large number of failures in Danish-designed Micon 65 wind turbines prompted this investigation. The high-speed and low-speed shaft torques were measured on a two-stage helical gearbox of a single Micon 65 turbine. Transient events and normal running loads were combined statistically to obtain a typical annual load spectrum. The pitting and bending fatigue lives of the gear teeth were calculated by using Miner's rule for four different high-speed shaft brake configurations. Each breaking scenario was run for both a high- and a low-turbulence normal operating load spectrum. The analysis showed increases in gear life by up to a factor of 25 when the standard high-speed shaft brake is replaced with a dynamic brake or modified with a damper. 9 refs., 9 figs., 3 tabs.
McNiff, B.P. (Second Wind, Inc., Somerville, MA (USA)); Musial, W.D. (Solar Energy Research Inst., Golden, CO (USA)); Errichello, R. (GEARTECH, Albany, CA (USA))
Pressure transient method for front tracking
A pressure transient technique for tracking the advance of cold water fronts during water flooding and goethermal injection operations has been developed. The technique is based on the concept that the steady state pressure buildup in the reservoir region inside the front can be calculated by a fluid skin factor. By analyzing successive pressure falloff tests, the advance of the front in the reservoir can be monitored. The validity of the methods is demonstrated by application to three numerically simulated data sets, a nonisothermal step-rate injection test, a series of pressure falloffs in a multilayered reservoir, and a series of pressure falloff tests in a water flooded oil reservoir.
Benson, S.M.; Bodvarsson, G.S.
Strings in plane-fronted gravitational waves
Brinkmann's plane-fronted gravitational waves with parallel rays --~shortly pp-waves~-- are shown to provide, under suitable conditions, exact string vacua at all orders of the sigma-model perturbation expansion.
C. Duval; Z. Horvath; P. A. Horvathy
Photoevaporation of protoplanetary discs II: evolutionary models and observable properties
We present a new model for protoplanetary disc evolution. This model combines viscous evolution with photoevaporation of the disc, in a manner similar to Clarke, Gendrin & Sotomayor (2001). However in a companion paper (Alexander, Clarke & Pringle 2006a) we have shown that at late times such models must consider the effect of stellar radiation directly incident on the inner disc edge, and here we model the observational implications of this process. We find that the entire disc is dispersed on a time-scale of order $10^5$yr after a disc lifetime of a few Myr, consistent with observations of T Tauri (TT) stars. We use a simple prescription to model the spectral energy distribution of the evolving disc, and demonstrate that the model is consistent with observational data across a wide range of wavelengths. We note also that the model predicts a short ``inner hole'' phase in the evolution of all TT discs, and make predictions for future observations at mid-infrared and millimetre wavelengths.
Design Principles of a flywheel Regenerative Braking System (f-RBS) for Formula SAE type racecar and system testing on a Virtual Test Rig modeled on MSC ADAMS
momentum in the industry [4]. These vehicles (BEVs and HEVS) use electric motor/generator pairs to propel themselves and to recapture braking energy (electric RBS) and the power source is the battery. The regenerative braking system uses a generator..., aerodynamic and road losses. 4. Improvised Transmission design to reduce losses. 5. Hybrid and Alternative Energy Propulsion systems e.g. the Hybrid Electric Vehicle (HEV), the Fuel Cell Vehicle (FCV). 6. Recycling Braking energy � Storage and reuse...
Pochiraju, Anirudh
The correct description of the standard Casimir effect for periodic boundary conditions via light front formalism implies in these conditions imposed at fixed Minkowski times [Almeida {\\it et al.} Phys. Rev. {\\bf D 87}, 065028 (2013); Chabysheva and Hiller, Phys. Rev. {\\bf D 88}, 085006 (2013)] instead of fixed light front times. The unphysical nature of this latter condition is manifested in the vacuum part by no regularization yielding a finite Casimir energy density [Lenz and Steinbacher, Phys. Rev. {\\bf D 67}, 045010 (2003)]. In the present paper, we extend this discussion and analyze the problem of the light front quantization with simultaneous presence of a thermal bath and boundary conditions. Considering both the oblique light front as well as Dirac light front coordinates, we show that the imposition of periodic boundary conditions at fixed Minkowski times recovers the expected behaviors for the energy density and Casimir entropy. We also investigate how the unphysical nature of the periodic boundary conditions imposed at fixed light front times manifests in the thermal part of the energy and entropy, showing that in the classical limit the Casimir entropy decreases linearly with the temperature (not becoming independent of the temperature as expected), and also that the Kirchhoff theorem is not respected.
P. L. M. Rodrigues; Silvana Perez; Danilo T. Alves; Van S�rgio Alves; Charles R. Silva
AUTOMATIC EXTRACTION OF THE OPTIC DISC BOUNDARY FOR DETECTING RETINAL DISEASES Muhammad Salman shape model for the extraction of Optic Disc boundary. The determination of Optic Disc boundary used as a reference point to lo- cate other retinal structures, and any structural change in Optic Disc
Li, Baihua
QCD and Light-Front Dynamics
AdS/QCD, the correspondence between theories in a dilaton-modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The result is a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. The hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. Higher Fock states with extra quark-anti quark pairs also arise. The soft-wall model also predicts the form of the nonperturbative effective coupling and its {beta}-function. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method to systematically include QCD interaction terms. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.
Brodsky, Stanley J.; de Teramond, Guy F.; /SLAC /Southern Denmark U., CP3-Origins /Costa Rica U.
accretion disc plasmas: Topics by E-print Network
should give insight into the magnetic dynamics of accretion discs and jets. A high-speed multiple-frame CCD camera reveals images of the formation and helical instability of a...
accretion disc models: Topics by E-print Network
we conjecture that the limiting field strength for a thin disc is such that the Alfven speed roughly equals the geometric mean of the Keplerian speed and the gas sound speed. We...
accretion disc model: Topics by E-print Network
Dynamic Bayesian networks for the classification of spinning discs
This thesis considers issues for the application of particle filters to a class of nonlinear filtering and classification problems. Specifically, we study a prototype system of spinning discs. The system combines linear ...
Schmidt, Aurora Clare, 1981-
The precession of eccentric discs in close binaries
We consider the precession rates of eccentric discs in close binaries, and compare theoretical predictions with the results of numerical disc simulations and with observed superhump periods. A simple dynamical model for precession is found to be inadequate. For mass ratios less than approximately 1/4 a linear dynamical model does provide an upper limit for disc precession rates. Theory suggests that pressure forces have a significant retrograde impact upon the precession rate (Lubow 1992). We find that the disc precession rates for three systems with accurately known mass ratios are significantly slower than predicted by the dynamical theory, and we attribute the difference to pressure forces. By assuming that pressure forces of similar magnitude occur in all superhumping systems, we obtain an improved fit to superhump observations.
James R. Murray
Deuterium depletion and magnesium enhancement in the local disc
The local disc deuter is known to be depleted in comparison to the local bubble. We show, that the same lines of sight that are depleted in deuter, are enhanced in magnesium. Heavier elements - Si and Fe do not show any difference in the abundance between the local disc and the local bubble. This observation implicates that astration is responsible for both deuter depletion and magnesium enhancement.
Piotr Gnacinski
Probability of failure of the waste hoist brake system at the Waste Isolation Pilot Plant (WIPP)
In its most recent report on the annual probability of failure of the waste hoist brake system at the Waste Isolation Pilot Plant (WIPP), the annual failure rate is calculated to be 1.3E({minus}7)(1/yr), rounded off from 1.32E({minus}7). A calculation by the Environmental Evaluation Group (EEG) produces a result that is about 4% higher, namely 1.37E({minus}7)(1/yr). The difference is due to a minor error in the US Department of Energy (DOE) calculations in the Westinghouse 1996 report. WIPP`s hoist safety relies on a braking system consisting of a number of components including two crucial valves. The failure rate of the system needs to be recalculated periodically to accommodate new information on component failure, changes in maintenance and inspection schedules, occasional incidents such as a hoist traveling out-of-control, either up or down, and changes in the design of the brake system. This report examines DOE`s last two reports on the redesigned waste hoist system. In its calculations, the DOE has accepted one EEG recommendation and is using more current information about the component failures rates, the Nonelectronic Parts Reliability Data (NPRD). However, the DOE calculations fail to include the data uncertainties which are described in detail in the NPRD reports. The US Nuclear Regulatory Commission recommended that a system evaluation include mean estimates of component failure rates and take into account the potential uncertainties that exist so that an estimate can be made on the confidence level to be ascribed to the quantitative results. EEG has made this suggestion previously and the DOE has indicated why it does not accept the NRC recommendation. Hence, this EEG report illustrates the importance of including data uncertainty using a simple statistical example.
Greenfield, M.A. [Univ. of California, Los Angeles, CA (United States); Sargent, T.J. [Univ. of Chicago, IL (United States)]|[Stanford Univ., CA (United States). Hoover Institution
Collapse of Magnetized Singular Isothermal Toroids: II. Rotation and Magnetic Braking
We study numerically the collapse of rotating, magnetized molecular cloud cores, focusing on rotation and magnetic braking during the main accretion phase of isolated star formation. Motivated by previous numerical work and analytic considerations, we idealize the pre-collapse core as a magnetized singular isothermal toroid, with a constant rotational speed everywhere. The collapse starts from the center, and propagates outwards in an inside-out fashion, satisfying exact self-similarity in space and time. For rotation rates and field strengths typical of dense low-mass cores, the main feature remains the flattening of the mass distribution along field lines -- the formation of a pseudodisk, as in the nonrotating cases. The density distribution of the pseudodisk is little affected by rotation. On the other hand, the rotation rate is strongly modified by pseudodisk formation. Most of the centrally accreted material reaches the vicinity of the protostar through the pseudodisk. The specific angular momentum can be greatly reduced on the way, by an order of magnitude or more, even when the pre-collapse field strength is substantially below the critical value for dominant cloud support. The efficient magnetic braking is due to the pinched geometry of the magnetic field in the pseudodisk, which strengthens the magnetic field and lengthens the level arm for braking. Both effects enhance the magnetic transport of angular momentum from inside to outside. The excess angular momentum is carried away in a low-speed outflow that has, despite claims made by other workers, little in common with observed bipolar molecular outflows. We discuss the implications of our calculations for the formation of true disks that are supported against gravity by rotation.
A. Allen; Z. Y. Li; F. H. Shu
Hybrid Braking System for Non-Drive Axles | Department of Energy
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
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Solar tracker motor having a fixed caliper and a translating caliper each with an electromagnetic brake system
Concepts and technologies described herein provide for an accurate and cost-effective method for rotating a solar array disk for tracking the movement of the sun. According to various aspects, a motor includes a fixed caliper and a translating caliper positioned adjacent to one another. Electromagnetically controlled brakes on the translating caliper grip the solar array disk while adjacent, but spaced apart, electromagnets on the fixed caliper and the translating caliper are energized to create an attractive force that pulls the translating caliper with the solar array disk toward the fixed caliper. After reaching the fixed caliper, brakes on the fixed caliper are engaged with the disk, brakes on the translating caliper are released from the disk, and the translating caliper is pushed back to the starting location where the process repeats until the desired rotation is completed.
Rau, Scott James
Friction forces on phase transition fronts
In cosmological first-order phase transitions, the microscopic interaction of the phase transition fronts with non-equilibrium plasma particles manifests itself macroscopically as friction forces. In general, it is a nontrivial problem to compute these forces, and only two limits have been studied, namely, that of very slow walls and, more recently, ultra-relativistic walls which run away. In this paper we consider ultra-relativistic velocities and show that stationary solutions still exist when the parameters allow the existence of runaway walls. Hence, we discuss the necessary and sufficient conditions for the fronts to actually run away. We also propose a phenomenological model for the friction, which interpolates between the non-relativistic and ultra-relativistic values. Thus, the friction depends on two friction coefficients which can be calculated for specific models. We then study the velocity of phase transition fronts as a function of the friction parameters, the thermodynamic parameters, and the amount of supercooling.
M�gevand, Ariel, E-mail: firstname.lastname@example.com [IFIMAR (CONICET�UNMdP), Departamento de F�sica, Facultad de Ciencias Exactas y Naturales, UNMdP, De�n Funes 3350, (7600) Mar del Plata (Argentina)
Rotational evolution of the Crab pulsar in the wind braking model
The pulsar wind model is updated by considering the effect of particle density and pulsar death. It can describe both the short term and long term rotational evolution of pulsars consistently. It is applied to model the rotational evolution of the Crab pulsar. The pulsar is spun down by a combination of magnetic dipole radiation and particle wind. The parameters of the Crab pulsar, including magnetic field, inclination angle, and particle density are calculated. The particle density in acceleration region is about 10^3 times the Goldreich-Julian charge density. The lower braking index between glitches is due to a larger particle density. This may be glitch induced magnetospheric activities in normal pulsars. Evolution of braking index and the Crab pulsar in P-Pdot diagram are calculated. The Crab pulsar will evolve from magnetic dipole radiation dominated case towards particle wind dominated case. Considering the effect of pulsar "death", the Crab pulsar (and other normal pulsars) will not evolve to the clust...
Kou, F F
ibm.com/redbooks Front cover
ibm.com/redbooks Front cover IBM XIV Storage System: Architecture, Implementation, and Usage Organization IBM XIV Storage System: Architecture, Implementation, and Usage September 2009 SG24-7659-01 #12 Storage System software. Note: Before using this information and the product it supports, read
Westall, James M.
Quadratic and Cubic ReactionDiffusion Fronts*
's student, Herr cand. Meinecke, moved a wire loop along the test tube to mark the position in the cytoplasm of frog oocytes [9], where calcium-induced calcium release provides a mechanism akin to auto- catalysis in chemical systems. Front-like calcium waves have also been found to occur on the surface
Showalter, Kenneth
COLORADO FRONT RANGE SEISMICITY AND SEISMIC HAZARD Anne F. Sheehan University of Colorado at Boulder, 2200 Colorado Avenue, Boulder, CO 80309 John D. Godchaux Trinity University, San Antonio, TX Noah Hughes University of Colorado at Boulder, 2200 Colorado Avenue, Boulder, CO 80309 Key Terms: earthquake
Sheehan, Anne F.
Hybrid: Braking
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QCD and Light-Front Holography
The soft-wall AdS/QCD model, modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics. The model predicts a zero-mass pion for zero-mass quarks and a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number N. Light-Front Holography maps the amplitudes which are functions of the fifth dimension variable z of anti-de Sitter space to a corresponding hadron theory quantized on the light front. The resulting Lorentz-invariant relativistic light-front wave equations are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. The result is to a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryon light-quark bound states, which in turn predict the behavior of the pion and nucleon form factors. The theory implements chiral symmetry in a novel way: the effects of chiral symmetry breaking increase as one goes toward large interquark separation, consistent with spectroscopic data, and the the hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. The soft-wall model also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q) and its {beta}-function which agrees with the effective coupling {alpha}{sub g1} extracted from the Bjorken sum rule. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms. A new perspective on quark and gluon condensates is also reviewed.
Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.; ,
Signs of a faint disc population at polluted white dwarfs
Observations of atmospheric metals and dust discs around white dwarfs provide important clues to the fate of terrestrial planetary systems around intermediate mass stars. We present Spitzer IRAC observations of 15 metal polluted white dwarfs to investigate the occurrence and physical properties of circumstellar dust created by the disruption of planetary bodies. We find subtle infrared excess emission consistent with warm dust around KUV 15519+1730 and HS 2132+0941, and weaker excess around the DZ white dwarf G245-58, which, if real, makes it the coolest white dwarf known to exhibit a 3.6 micron excess and the first DZ star with a bright disc. All together our data corroborate a picture where 1) discs at metal-enriched white dwarfs are commonplace and most escape detection in the infrared (possibly as narrow rings), 2) the discs are long lived, having lifetimes on the order of 10^6 yr or longer, and 3) the frequency of bright, infrared detectable discs decreases with age, on a timescale of roughly 500 Myr, su...
Bergfors, Carolina; Dufour, Patrick; Rocchetto, Marco
Gap formation and stability in non-isothermal protoplanetary discs
Several observations of transition discs show lopsided dust-distributions. A potential explanation is the formation of a large-scale vortex acting as a dust-trap at the edge of a gap opened by a giant planet. Numerical models of gap-edge vortices have thus far employed locally isothermal discs, but the theory of this vortex-forming or `Rossby wave' instability was originally developed for adiabatic discs. We generalise the study of planetary gap stability to non-isothermal discs using customised numerical simulations of disc-planet systems where the planet opens an unstable gap. We include in the energy equation a simple cooling function with cooling timescale $t_c=\\beta\\Omega_k^{-1}$, where $\\Omega_k$ is the Keplerian frequency, and examine the effect of $\\beta$ on the stability of gap edges and vortex lifetimes. We find increasing $\\beta$ lowers the growth rate of non-axisymmetric perturbations, and the dominant azimuthal wavenumber $m$ decreases. We find a quasi-steady state consisting of one large-scale, ...
Les, Robert
Verification tests of the U. S. Electricar Corporation Lectric Leopard. Technical report 3 Aug-25 Sep 81
The Lectric Leopard manufactured by U.S. Electricar Corporation was tested at MERADCOM as part of the Department of Energy project to verify conformity to performance standards of electric vehicles. The Leopard is a standard Fiat Strada sedan which has been converted to an electric vehicle. It is powered by 16 6-V batteries through a silicon-controlled rectifier (SCR) Controller to a 23-hp series-wound d.c. motor. It is equipped with a five-speed manual transmission, power-assisted disc brakes in the front and drum brakes in the rear. It is not equipped with regenerative braking.
Dowgiallo, E.J. Jr; Snellings, I.R.; Chapman, R.D.
Use of an auditory signal in a rear-end collision warning system: effects on braking force and reaction time
driving game. Superimposed on the game screen was the image of a car which appeared to the driver to be ahead of him/her. The image enlarged in size, appearing to be a car applying its brakes. The participant was instructed to react as he would in a real...
Hopkins, Jennifer Susan
CityCarControl : an electric vehicle drive-by-wire solution for distributed steering, braking and throttle control
In this paper, we propose CityCarControl, a system to manage the steering, braking, and throttle of a new class of intra-city electric vehicles. These vehicles have a focus on extreme light-weight and a small parking ...
Brown, Thomas B., M. Eng. Massachusetts Institute of Technology
Density waves in the shearing sheet III. Disc heating
The problem of dynamical heating of galactic discs by spiral density waves is discussed using the shearing sheet model. The secular evolution of the disc is described quantitatively by a diffusion equation for the distribution function of stars in the space spanned by integrals of motion of the stars, in particular the radial action integral and an integral related to the angular momentum. Specifically, disc heating by a succession of transient, `swing amplified' density waves is studied. It is shown that such density waves lead predominantly to diffusion of stars in radial action space. The stochastical changes of angular momenta of the stars and the corresponding stochastic changes of the guiding centre radii of the stellar orbits induced by this process are much smaller.
B. Fuchs
Some challenges and directions for next generation accretion disc theory
Accretion disc theory is far less developed than that of stellar evolution, although a similarly mature phenomenological picture is ultimately desired. While conceptual progress from the interplay of theory and numerical simulations has amplified awareness of the role of magnetic fields in angular momentum transport, there remains a significant gap between the output of magneto-rotational instability (MRI) simulations and the synthesis of lessons learned into improved practical models. If discs are turbulent, then axisymmetric models must be recognized to be sensible only as mean field theories. Such is the case for the wonderfully practical and widely used framework of Shakura-Sunyaev (SS73). This model is most justifiable when the radial angular momentum transport dominates in discs and the transport is assumed to take the form of a local viscosity. However, the importance of large scale fields in coronae and jets and numerical evidence from MRI simulations points to a significant fraction of transport bein...
Blackman, Eric G
Abundances of metal-weak thick-disc candidates
High resolution spectra of 5 candidate metal-weak thick-disc stars suggested by Beers & Sommer-Larsen (1995) are analyzed to determine their chemical abundances. The low abundance of all the objects has been confirmed with metallicity reaching [Fe/H]=-2.9. However, for three objects, the astrometric data from the Hipparcos catalogue suggests they are true halo members. The remaining two, for which proper-motion data are not available, may have disc-like kinematics. It is therefore clear that it is useful to address properties of putative metal-weak thick-disc stars only if they possess full kinematic data. For CS 22894-19 the abundance pattern similar to those of typical halo stars is found, suggesting that chemical composition is not a useful discriminant between thick-disc and halo stars. CS 29529-12 is found to be C enhanced with [C/Fe]=+1.0; other chemical peculiarities involve the s process elements: [Sr/Fe]=-0.65 and [Ba/Fe]=+0.62, leading to a high [Ba/Sr] considerably larger than what is found in more metal-rich carbon-rich stars, but similar to LP 706-7 and LP 625-44 discussed by Norris et al (1997a). Hipparcos data have been used to calculate the space velocities of 25 candidate metal-weak thick-disc stars, thus allowing us to identify 3 bona fide members, which support the existence of a metal-poor tail of the thick-disc, at variance with a claim to the contrary by Ryan & Lambert (1995).
P. Bonifacio; M. Centurion; P. Molaro
E-Print Network 3.0 - attenuating disc wind Sample Search Results
disc wind Search Powered by Explorit Topic List Advanced Search Sample search results for: attenuating disc wind Page: << < 1 2 3 4 5 > >> 1 Mon. Not. R. Astron. Soc. 400, 629645...
We study numerically the collapse of rotating, magnetized molecular cloud cores, focusing on rotation and magnetic braking during the main accretion phase of isolated star formation. Motivated by previous numerical work and analytic considerations, we idealize the pre-collapse core as a magnetized singular isothermal toroid, with a constant rotational speed everywhere. The collapse starts from the center, and propagates outwards in an inside-out fashion, satisfying exact self-similarity in space and time. For rotation rates and field strengths typical of dense low-mass cores, the main feature remains the flattening of the mass distribution along field lines -- the formation of a pseudodisk, as in the nonrotating cases. The density distribution of the pseudodisk is little affected by rotation. On the other hand, the rotation rate is strongly modified by pseudodisk formation. Most of the centrally accreted material reaches the vicinity of the protostar through the pseudodisk. The specific angular momentum can b...
Allen, A; Shu, F H
Front contact solar cell with formed emitter
A bipolar solar cell includes a backside junction formed by an N-type silicon substrate and a P-type polysilicon emitter formed on the backside of the solar cell. An antireflection layer may be formed on a textured front surface of the silicon substrate. A negative polarity metal contact on the front side of the solar cell makes an electrical connection to the substrate, while a positive polarity metal contact on the backside of the solar cell makes an electrical connection to the polysilicon emitter. An external electrical circuit may be connected to the negative and positive metal contacts to be powered by the solar cell. The positive polarity metal contact may form an infrared reflecting layer with an underlying dielectric layer for increased solar radiation collection.
Cousins, Peter John
Cousins, Peter John (Menlo Park, CA)
Light-front chiral effective field theory
We propose a general framework to calculate the nonperturbative structure of relativistic bound state systems. The state vector of the bound state is calculated in the covariant formulation of light-front dynamics. In this scheme, the state vector is defined on the light front of general position {omega} {center_dot} x = 0, where {omega} is an arbitrary light-like four-vector. This enables a strict control of any violation of rotational invariance. The state vector is then decomposed in Fock components. Our formalism is applied to the description of the nucleon properties at low energy, in chiral perturbation theory. We also show that the use of a recently proposed regularization scheme, the so-called Taylor-Lagrange regularization scheme, is very adequate in order to treat divergences in this nonperturbative framework.
Mathiot, J.-F. [Laboratoire de Physique Corpusculaire (France)] [Laboratoire de Physique Corpusculaire (France); Tsirova, N. A., E-mail: email@example.com [Samara State University (Russian Federation)
Pentan isomers compound flame front structure
The fuels (hexane, pentane, diethyl ether) and conditions investigated in this study are relevant to engine knock in spark- ignition engines. A review is provided of the field of low temperature hydrocarbon oxidation. Studies were made of radical and stable intermediate distribution in the front of cool flames: Maximum concentrations of H atoms and peroxy radicals were observed in the luminous zone of the cool flame front. Peroxy radicals appear before the luminous zone at 430 K due to diffusion. H atoms were found in cool flames of butane and hexane. H atoms diffuses from the luminous zone to the side of the fresh mixture, and they penetrate into the fresh mixture to a small depth. Extension of action sphear of peroxy radicals in the fresh mixture is much greater than that of H atoms due to their small activity and high concentrations.
Mansurov, Z.A.; Mironenko, A.W.; Bodikov, D.U.; Rachmetkaliev, K.N. [Kazakh Al-Farabi State National Univ., Almaty (Kazakhstan)
The Formation and Survival of Discs in a Lambda-CDM Universe
We study the formation of galaxies in a Lambda-CDM Universe using high resolution hydrodynamical simulations with a multiphase treatment of gas, cooling and feedback, focusing on the formation of discs. Our simulations follow eight haloes similar in mass to the Milky Way and extracted from a large cosmological simulation without restriction on spin parameter or merger history. This allows us to investigate how the final properties of the simulated galaxies correlate with the formation histories of their haloes. We find that, at z = 0, none of our galaxies contain a disc with more than 20 per cent of its total stellar mass. Four of the eight galaxies nevertheless have well-formed disc components, three have dominant spheroids and very small discs, and one is a spheroidal galaxy with no disc at all. The z = 0 spheroids are made of old stars, while discs are younger and formed from the inside-out. Neither the existence of a disc at z = 0 nor the final disc-to-total mass ratio seems to depend on the spin parameter of the halo. Discs are formed in haloes with spin parameters as low as 0.01 and as high as 0.05; galaxies with little or no disc component span the same range in spin parameter. Except for one of the simulated galaxies, all have significant discs at z > ~2, regardless of their z = 0 morphologies. Major mergers and instabilities which arise when accreting cold gas is misaligned with the stellar disc trigger a transfer of mass from the discs to the spheroids. In some cases, discs are destroyed, while in others, they survive or reform. This suggests that the survival probability of discs depends on the particular formation history of each galaxy. A realistic Lambda-CDM model will clearly require weaker star formation at high redshift and later disc assembly than occurs in our models.
Cecilia Scannapieco; Simon D. M. White; Volker Springel; Patricia B. Tissera
Colloid Formation at Waste Plume Fronts
Highly saline and caustic tank waste solutions containing radionuclides and toxic metals have leaked into sediments at U. S. Department of Energy (DOE) facilities such as the Hanford Site (Washington State). Colloid transport is frequently invoked to explain migration of radionuclides and metals in the subsurface. To understand colloid formation during interactions between highly reactive fluids and sediments and its impact on contaminant transport, we simulated tank waste solution (TWS) leakage processes in laboratory columns at ambient and elevated (70 C) temperatures. We found that maximum formation of mobile colloids occurred at the plume fronts (hundreds to thousands times higher than within the plume bodies or during later leaching). Concentrations of suspended solids were as high as 3 mass%, and their particle-sizes ranged from tens of nm to a few {micro}m. Colloid chemical composition and mineralogy depended on temperature. During infiltration of the leaked high Na{sup +} waste solution, rapid and completed Na{sup +} replacement of exchangeable Ca{sup 2+} and Mg{sup 2+} from the sediment caused accumulation of these divalent cations at the moving plume front. Precipitation of supersaturated Ca{sup 2+}/Mg{sup 2+}-bearing minerals caused dramatic pH reduction at the plume front. In turn, the reduced pH caused precipitation of other minerals. This understanding can help predict the behavior of contaminant trace elements carried by the tank waste solutions, and could not have been obtained through conventional batch studies.
Wan, Jiamin; Tokunaga, Tetsu K.; Saiz, Eduardo; Larsen, Joern T.; Zheng, Zuoping; Couture, Rex A.
Feedback in simulations of disc-galaxy major mergers
Using hydrodynamic simulations of disc-galaxy major mergers, we investigate the star formation history and remnant properties when various parametrizations of a simple stellar feedback model are implemented. The simulations include radiative cooling, a density-dependent star formation recipe and a model for feedback from massive stars. The feedback model stores supernova feedback energy within individual gas particles and dissipates this energy on a time-scale specified by two free parameters; tau_fb, which sets the dissipative time-scale, and n, which sets the effective equation of state in star-forming regions. Using a self-consistent disc galaxy, modelled after a local Sbc spiral, in both isolated and major-merger simulations, we investigate parametrizations of the feedback model that are selected with respect to the quiescent disc stability. These models produce a range of star formation histories that are consistent with the star formation relation found by Kennicutt. All major mergers produce a population of new stars that is highly centrally concentrated, demonstrating a distinct break in the r1/4 surface density profile, consistent with previous findings. The half-mass radius and one-dimensional velocity dispersion are affected by the feedback model used. Finally, we compare our results to those of previous simulations of star formation in disc-galaxy major mergers, addressing the effects of star formation normalization, the version of smoothed particle hydrodynamics (SPH) employed and assumptions about the interstellar medium.
T. J. Cox; Patrik Jonsson; Joel R. Primack; Rachel S. Somerville
Jupiter and Super-Earth embedded in a gaseous disc
In this paper we investigate the evolution of a pair of interacting planets - a Jupiter mass planet and a Super-Earth with the 5.5 Earth masses - orbiting a Solar type star and embedded in a gaseous protoplanetary disc. We focus on the effects of type I and II orbital migrations, caused by the planet-disc interaction, leading to the Super-Earth capture in first order mean motion resonances by the Jupiter. The stability of the resulting resonant system in which the Super-Earth is on the internal orbit relatively to the Jupiter has been studied numerically by means of full 2D hydrodynamical simulations. Our main motivation is to determine the Super-Earth behaviour in the presence of the gas giant in the system. It has been found that the Jupiter captures the Super-Earth into the interior 3:2 or 4:3 mean motion resonances and the stability of such configurations depends on the initial planet positions and eccentricity evolution. If the initial separation of planet orbits is larger or close to that required for the exact resonance than the final outcome is the migration of the pair of planets with the rate similar to that of the gas giant at least for time of our simulations. Otherwise we observe a scattering of the Super-Earth from the disc. The evolution of planets immersed in the gaseous disc has been compared with their behaviour in the case of the classical three-body problem when the disc is absent.
E. Podlewska; E. Szuszkiewicz
Nonperturbative calculations in light-front QED
The methods of light-front quantization and Pauli-Villars regularization are applied to a nonperturbative calculation of the dressed-electron state in quantum electrodynamics. This is intended as a test of the methods in a gauge theory, as a precursor to possible methods for the nonperturbative solution of quantum chromodynamics. The electron state is truncated to include at most two photons and no positrons in the Fock basis, and the wave functions of the dressed state are used to compute the electrons's anomalous magnetic moment. A choice of regularization that preserves the chiral symmetry of the massless limit is critical for the success of the calculation.
Chabysheva, Sophia S. [Department of Physics, University of Minnesota-Duluth, Duluth, Minnesota 55812 (United States)
Sandia National Laboratories: Front Edge Technology Inc.
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -theErik Spoerke SSLS Exhibit at Explora MuseumFloatingFront Edge Technology Inc.
Identifying Lagrangian fronts with favourable fishery conditions
Lagrangian fronts (LF) in the ocean delineate boundaries between surface waters with different Lagrangian properties. They can be accurately detected in a given velocity field by computing synoptic maps of the drift of synthetic tracers and other Lagrangian indicators. Using Russian ship's catch and location data for a number of commercial fishery seasons in the region of the northwest Pacific with one of the richest fishery in the world, it is shown statistically that the saury fishing grounds with maximal catches are not randomly distributed over the region but located mainly along those LFs where productive cold waters of the Oyashio Current, warmer waters of the southern branch of the Soya Current, and waters of warm-core Kuroshio rings converge. Computation of those fronts with the altimetric geostrophic velocity fields both in the years with the First and Second Oyashio Intrusions shows that in spite of different oceanographic conditions the LF locations may serve good indicators of potential fishing grounds. Possible reasons for saury aggregation near LFs are discussed. We propose a mechanism of effective export of nutrient rich waters based on stretching of material lines in the vicinity of hyperbolic objects in the ocean. The developed method, based on identifying LFs in any velocity fields, is quite general and may be applied to forecast potential fishing grounds for the other pelagic fishes in different seas and the oceans.
S. V. Prants; M. V. Budyansky; M. Yu. Uleysky
Characterising the Gravitational Instability in Cooling Accretion Discs
We perform numerical analyses of the structure induced by gravitational instabilities in cooling gaseous accretion discs. For low enough cooling rates a quasi-steady configuration is reached, with the instability saturating at a finite amplitude in a marginally stable disc. We find that the saturation amplitude scales with the inverse square root of the cooling parameter beta = t_cool / t_dyn, which indicates that the heating rate induced by the instability is proportional to the energy density of the induced density waves. We find that at saturation the energy dissipated per dynamical time by weak shocks due is of the order of 20 per cent of the wave energy. From Fourier analysis of the disc structure we find that while the azimuthal wavenumber is roughly constant with radius, the mean radial wavenumber increases with radius, with the dominant mode corresponding to the locally most unstable wavelength. We demonstrate that the density waves excited in relatively low mass discs are always close to co-rotation, deviating from it by approximately 10 per cent. This can be understood in terms of the flow Doppler-shifted phase Mach number -- the pattern speed self-adjusts so that the flow into spiral arms is always sonic. This has profound effects on the degree to which transport through self-gravity can be modelled as a viscous process. Our results thus provide (a) a detailed description of how the self-regulation mechanism is established for low cooling rates, (b) a clarification of the conditions required for describing the transport induced by self-gravity through an effective viscosity, (c) an estimate of the maximum amplitude of the density perturbation before fragmentation occurs, and (d) a simple recipe to estimate the density perturbation in different thermal regimes.
Peter Cossins; Giuseppe Lodato; Cathie Clarke
Magnesium Front End Design And Development (AMD603)
firstname.lastname@example.com February 28, 2008 Magnesium Front End Design And Development (AMD603) This presentation does not contain any proprietary or confidential information USAMP 2008...
apennine front kreep: Topics by E-print Network
Department of Chemical Engineering References and links 1. J. Warnatz, U. Maas, and R.W. Dibble, Combustion - physical and chemical fundamentals, "Characterization of flame front...
The Front Burner Cybersecurity The ACIO for Cybersecurity
Special Edition of The Front Burner Cybersecurity The ACIO for Cybersecurity Issue No. 13 October 2012 National Cybersecurity Awareness Month October 2012 The Department of Energy...
Light-Front Holography, Light-Front Wavefunctions, and Novel QCD Phenomena
Light-Front Holography is one of the most remarkable features of the AdS/CFT correspondence. In spite of its present limitations it provides important physical insights into the nonperturbative regime of QCD and its transition to the perturbative domain. This novel framework allows hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time. The model leads to an effective confining light-front QCD Hamiltonian and a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time and determines the off-shell dynamics of the bound-state wavefunctions, and thus the fall-off as a function of the invariant mass of the constituents. The soft-wall holographic model modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics - a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryons. The model predicts a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number n. The hadron eigensolutions projected on the free Fock basis provides the complete set of valence and non-valence light-front Fock state wavefunctions {Psi}{sub n/H} (x{sub i}, k{sub {perpendicular}i}, {lambda}{sub i}) which describe the hadron's momentum and spin distributions needed to compute the direct measures of hadron structure at the quark and gluon level, such as elastic and transition form factors, distribution amplitudes, structure functions, generalized parton distributions and transverse momentum distributions. The effective confining potential also creates quark-antiquark pairs from the amplitude q {yields} q{bar q}q. Thus in holographic QCD higher Fock states can have any number of extra q{bar q} pairs. We discuss the relevance of higher Fock-states for describing the detailed structure of space and time-like form factors. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms. A new perspective on quark and gluon condensates is also obtained.
Front lighted optical tooling method and apparatus
An optical tooling method and apparatus uses a front lighted shadowgraphic technique to enhance visual contrast of reflected light. The apparatus includes an optical assembly including a fiducial mark, such as cross hairs, reflecting polarized light with a first polarization, a polarizing element backing the fiducial mark and a reflective surface backing the polarizing element for reflecting polarized light bypassing the fiducial mark and traveling through the polarizing element. The light reflected by the reflecting surface is directed through a second pass of the polarizing element toward the frontal direction with a polarization differing from the polarization of the light reflected by the fiducial mark. When used as a tooling target, the optical assembly may be mounted directly to a reference surface or may be secured in a mounting, such as a magnetic mounting. The optical assembly may also be mounted in a plane defining structure and used as a spherometer in conjunction with an optical depth measuring instrument.
Stone, W.J.
Front contact solar cell with formed electrically conducting layers on the front side and backside
A bipolar solar cell includes a backside junction formed by a silicon substrate and a first doped layer of a first dopant type on the backside of the solar cell. A second doped layer of a second dopant type makes an electrical connection to the substrate from the front side of the solar cell. A first metal contact of a first electrical polarity electrically connects to the first doped layer on the backside of the solar cell, and a second metal contact of a second electrical polarity electrically connects to the second doped layer on the front side of the solar cell. An external electrical circuit may be electrically connected to the first and second metal contacts to be powered by the solar cell.
On the precession of accretion discs in X-ray binaries
In this letter recent results on the nodal precession of accretion discs in close binaries are applied to the discs in some X-ray binary systems. The ratio between the tidally forced precession period and the binary orbital period is given, as well as the condition required for the rigid precession of gaseous Keplerian discs. Hence the minimum precessional period that may be supported by a fluid Keplerian disc is determined. It is concluded that near rigid body precession of tilted accretion discs can occur and generally reproduce observationally inferred precession periods, for reasonable system parameters. In particular long periods in SS433, Her X-1, LMC X-4 and SMC X-1 can be fit by the tidal model. It is also found that the precession period that has been tentatively put forward for Cyg X-2 cannot be accomodated by a tidally precessing disc model for any realistic choice of system parameters.
J. Larwood
Heuristically Driven Front Propagation for Fast Geodesic Extraction
Heuristically Driven Front Propagation for Fast Geodesic Extraction Gabriel Peyr´e Laurent D. Cohen to quickly extract geodesic paths on images and 3D meshes. We use a heuristic to drive the front propagation that is similar to the A algorithm used in artificial intelli- gence. In order to find very quickly geodesic paths
Combustion fronts in porous media with two layers Steve Schecter
Combustion fronts in porous media with two layers layer 1 layer 2 Steve Schecter North Carolina Subject: Propagation of a combustion front through a porous medium with two parallel layers having different properties. · Each layer admits a traveling combustion wave. · The layers are coupled by heat
Schecter, Stephen
FLUCTUATIONS OF THE FRONT IN A STOCHASTIC COMBUSTION MODEL #1; (FLUCTUATIONS DU FRONT DANS UN MOD�?LE DE COMBUSTION) FRANCIS COMETS 1 , JEREMY QUASTEL 2 AND ALEJANDRO F. RAMÍREZ 3 Abstract. We consider an interacting particle system on the one dimensional lattice Z modeling combustion. The process
Quastel, Jeremy
Description and Simulation of Gust Front Wind Field Lijuan Wanga
-stationarity of the wind field associated with these extreme events poses serious challenges in their modelingDescription and Simulation of Gust Front Wind Field Lijuan Wanga , Ahsan Kareemb a Nat front wind field is proposed based on the time-frequency description of the wind field. Traditionally
Kareem, Ahsan
Light-Front Holography: A First Approximation to QCD
Starting from the Hamiltonian equation of motion in QCD, we identify an invariant light-front coordinate {zeta} which allows the separation of the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single variable light-front Schroedinger equation for QCD which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. This light-front wave equation is equivalent to the equations of motion which describe the propagation of spin-J modes on anti-de Sitter (AdS) space. This allows us to establish formally a gauge/gravity correspondence between an effective gravity theory defined on AdS5 and light front QCD.
de Teramond, Guy F.; Brodsky, Stanley J.
Dust filtration at gap edges: Implications for the spectral energy distributions of discs with embedded planets
The spectral energy distributions (SEDs) of some T Tauri stars display a deficit of near-IR flux that could be a consequence of an embedded Jupiter-mass planet partially clearing an inner hole in the circumstellar disc. Here, we use two-dimensional numerical simulations of the planet-disc interaction, in concert with simple models for the dust dynamics, to quantify how a planet influences the dust at different radii within the disc. We show that pressure gradients at the outer edge of the gap cleared by the planet act as a filter - letting particles smaller than a critical size through to the inner disc while holding back larger particles in the outer disc. The critical particle size depends upon the disc properties, but is typically of the order of 10 microns. This filtration process will lead to discontinuous grain populations across the planet's orbital radius, with small grains in the inner disc and an outer population of larger grains. We show that this type of dust population is qualitatively consistent with SED modelling of systems that have optically thin inner holes in their circumstellar discs. This process can also produce a very large gas-to-dust ratio in the inner disc, potentially explaining those systems with optically thin inner cavities that still have relatively high accretion rates.
W. K. M. Rice; Philip J. Armitage; Kenneth Wood; Giuseppe Lodato
E-Print Network 3.0 - actuator disc flow Sample Search Results
search results for: actuator disc flow Page: << < 1 2 3 4 5 > >> 1 The selection of mechanical actuators based on performance indices Summary: and pneumatic actuators provide...
E-Print Network 3.0 - artificial intervertebral disc Sample Search...
search results for: artificial intervertebral disc Page: << < 1 2 3 4 5 > >> 1 MECHANICAL AND AEROSPACE ENGINEERING COLLOQUIUM SERIES Summary: MECHANICAL AND AEROSPACE...
E-Print Network 3.0 - artificial disc arthroplasty Sample Search...
Engineering ; Biology and Medicine 70 Pressuredriven outflow and magnetocentrifugal wind from a dynamo active disc Summary: Pressure-driven outflow and magneto-centrifugal...
E-Print Network 3.0 - artificial disc activ Sample Search Results
; Environmental Sciences and Ecology 9 Pressuredriven outflow and magnetocentrifugal wind from a dynamo active disc Summary: Pressure-driven outflow and magneto-centrifugal...
E-Print Network 3.0 - altered disc pressure Sample Search Results
Sciences ; Biology and Medicine 33 Pressuredriven outflow and magnetocentrifugal wind from a dynamo active disc Summary: Pressure-driven outflow and magneto-centrifugal...
Webinar: Testing Oxygen Reduction Reaction Activity with the Rotating Disc Electrode Technique
Video recording of the Fuel Cell Technologies Office webinar, Testing Oxygen Reduction Reaction Activity with the Rotating Disc Electrode Technique, originally presented on March 12, 2013.
A closed-loop quasi-optimal dynamic braking resistor and shunt reactor control strategy for transient stability
A control strategy for dynamic braking resistor and shunt reactor is proposed for stabilization of power systems when subject to large disturbances. The time optimal control is derived as a function of synchronous machine power, its rotor angular position and speed deviation. The response for a single machine system with the proposed control has been compared with that from the time optimal solution obtained through the steepest descent method. The strategy has also been tested on two multimachine systems. Results indicate that the proposed strategy provides a simple and effective method of stabilization under transient emergency conditions.
Rahim, A.H.M.A.; Alamgir, D.A.H.
Flame front geometry in premixed turbulent flames
Experimental and numerical determinations of flame front curvature and orientation in premixed turbulent flames are presented. The experimental data is obtained from planar, cross sectional images of stagnation point flames at high Damkoehler number. A direct numerical simulation of a constant energy flow is combined with a zero-thickness, constant density flame model to provide the numerical results. The computational domain is a 32{sup 3} cube with periodic boundary conditions. The two-dimensional curvature distributions of the experiments and numerical simulations compare well at similar q{prime}/S{sub L} values with means close to zero and marked negative skewness. At higher turbulence levels the simulations show that the distributions become symmetric about zero. These features are also found in the three dimensional distributions of curvature. The simulations support assumptions which make it possible to determine the mean direction cosines from the experimental data. This leads to a reduction of 12% in the estimated flame surface area density in the middle of the flame brush. 18 refs.
Shepherd, I.G. (Lawrence Berkeley Lab., CA (United States)); Ashurst, W.T. (Sandia National Labs., Livermore, CA (United States))
An optical tooling method and apparatus uses a front lighted shadowgraphic technique to enhance visual contrast of reflected light. The apparatus includes an optical assembly including a fiducial mark, such as cross hairs, reflecting polarized light with a first polarization, a polarizing element backing the fiducial mark and a reflective surface backing the polarizing element for reflecting polarized light bypassing the fiducial mark and traveling through the polarizing element. The light reflected by the reflecting surface is directed through a second pass of the polarizing element toward the frontal direction with a polarization differing from the polarization of the light reflected by the fiducial mark. When used as a tooling target, the optical assembly may be mounted directly to a reference surface or may be secured in a mounting, such as a magnetic mounting. The optical assembly may also be mounted in a plane defining structure and used as a spherometer in conjunction with an optical depth measuring instrument. A method of measuring a radius of curvature of an unknown surface includes positioning the spherometer on a surface between the surface and a depth measuring optical instrument. As the spherometer is frontally illuminated, the distance from the depth measuring instrument to the fiducial mark and the underlying surface are alternately measured and the difference in these measurements is used as the sagittal height to calculate a radius of curvature.
Stone, William J. (Kansas City, MO)
Electron g-2 in Light-Front Quantization
Basis Light-front Quantization has been proposed as a nonperturbative framework for solving quantum field theory. We apply this approach to Quantum Electrodynamics and explicitly solve for the light-front wave function of a physical electron. Based on the resulting light-front wave function, we evaluate the electron anomalous magnetic moment. Nonperturbative mass renormalization is performed. Upon extrapolation to the infinite basis limit our numerical results agree with the Schwinger result obtained in perturbation theory to an accuracy of 0.06%.
Xingbo Zhao; Heli Honkanen; Pieter Maris; James P. Vary; Stanley J. Brodsky
Home Front as Warfront: African American World War I Drama
This dissertation recovers little-known African American World War I plays that blur the boundary between the home front and warfront. I argue that with this focus, the plays wage their own war for African American citizenship ...
Egging, Anna Katherine
Advanced integrated safeguards using front-end-triggering devices
This report addresses potential uses of front-end-triggering devices for enhanced safeguards. Such systems incorporate video surveillance as well as radiation and other sensors. Also covered in the report are integration issues and analysis techniques.
Howell, J.A.; Whitty, W.J.
Carbon Emissions from Smouldering Peat in Shallow and Strong Fronts�
A series of experiments of shallow and strong smouldering fronts in boreal peat have been conducted under laboratory conditions to study the CO and CO2 emissions. Peat samples of 100 mm by 100 mm in cross section and 50 ...
Rein, Guillermo; Cohen, Simon; Simeoni, Albert
Global optimization of silicon photovoltaic cell front coatings
The front-coating (FC) of a solar cell controls its efficiency, determining admission of light into the absorbing material and potentially trapping light to enhance thin absorbers. Single-layer FC designs are well known, ...
Ghebrebrhan, Michael
Speed-up of combustion fronts in shear flows
This paper is concerned with the analysis of speed-up of reaction-diffusion-advection traveling fronts in infinite cylinders with periodic boundary conditions. The advection is a shear flow with a large amplitude and the reaction is nonnegative, with either positive or zero ignition temperature. The unique or minimal speeds of the traveling fronts are proved to be asymptotically linear in the flow amplitude as the latter goes to infinity, solving an open problem from \\cite{b}. The asymptotic growth rate is characterized explicitly as the unique or minimal speed of traveling fronts for a limiting degenerate problem, and the convergence of the regular traveling fronts to the degenerate ones is proved for positive ignition temperatures under an additional H{\\"{o}}rmander-type condition on the flow.
Hamel, Francois
Colorado Front Range Fuel Photo Series Michael A. Battaglia
Colorado Front Range Fuel Photo Series Michael A. Battaglia Jonathan M. Dodson Wayne D. Shepperd of Agriculture Forest Service Rocky Mountain Research Station June 2005 #12;Battaglia, Michael A.; Dodson
Fried, Jeremy S.
Renormalized Light Front Hamiltonian in the Pauli-Villars Regularization
We address the problem of nonperturbative calculations on the light front in quantum field theory regularized by Pauli-Villars method. As a preliminary step we construct light front Hamiltonians in (2+1)-dimensional $\\lambda\\phi^4$ model, for the cases without and with spontaneous symmetry breaking. The renormalization of these Hamiltonians in Pauli-Villars regularization is carried out via comparison of all-order perturbation theory, generated by these Hamiltonians, and the corresponding covariant perturbation theory in Lorentz coordinates.
M. Yu. Malyshev; S. A. Paston; E. V. Prokhvatilov; R. A. Zubov
Optically Thick Outflows of Supercritical Accretion Discs: Radiative Diffusion Approach
Highly supercritical accretion discs are probable sources of dense optically thick axisymmetric winds. We introduce a new approach based on diffusion approximation radiative transfer in a funnel geometry and obtain an analytical solution for the energy density distribution inside the wind assuming that all the mass, momentum and energy are injected well inside the spherization radius. This allows to derive the spectrum of emergent emission for various inclination angles. We show that self-irradiation effects play an important role altering the temperature of the outcoming radiation by about 20% and the apparent X-ray luminosity by a factor of 2-3. The model has been successfully applied to two ULXs. The basic properties of the high ionization HII-regions found around some ULXs are also easily reproduced in our assumptions.
P. Abolmasov; S. Karpov; Taro Kotani
Hydraulic Drivetrain and Regenerative Braking Team 13: Andrew Brown, Karan Desai, Andrew McGrath, Hurst Nuckols, Grant Wilson Adviser: Dr. Andrew Jackson
Hydraulic Drivetrain and Regenerative Braking Team 13: Andrew Brown, Karan Desai, Andrew Mc Pressure Reservior Filter Variable Vane Pump Motor/Pump Hydraulic Accumulators Solenoid Valve Relief Valve Suction Line Since their development in 2006, hydraulic drivetrain systems have gained considerable
Carpick, Robert W.
Vehicle System Dynamics, Vol. 26, No.4, October 1996, pp.301-320. Traction/Braking Force Distribution for Optimal Longitudinal
as the desired level of vehicle yaw motion, and the control system was designed to follow the yaw motion commandVehicle System Dynamics, Vol. 26, No.4, October 1996, pp.301-320. Traction/Braking Force in the past twenty years through the use of electronic devices. Four-wheel-steering (4WS) systems have been
Peng, Huei
On fan-shaped cold MHD winds from Keplerian accretion discs
We investigate under which conditions cold, fan-shaped winds can be steadily launched from thin (Keplerian) accretion discs. Such winds are magneto-centrifugal winds launched from a thin annulus in the disc, along open magnetic field lines that fan out above the disc. In principle, such winds could be found in two situations: (1) at the interface between an inner Jet Emitting Disc, which is itself powering magneto-centrifugally driven winds, and an outer standard accretion disc; (2) at the interface between an inner closed stellar magnetosphere and the outer standard accretion disc. We refer to Terminal or T-winds to the former kind and to Magnetospheric or M-winds to the latter. The full set of resistive and viscous steady state MHD equations are analyzed for the disc (the annulus), which allow us to derive general expressions valid for both configurations. We find that, under the framework of our analysis, the only source of energy able to power any kind of fan-shaped winds is the viscous transport of rotat...
Ferreira, Jonathan
Massive planets in FU Orionis discs: implications for thermal instability models
FU Orionis are young stellar objects undergoing episodes of enhanced luminosity, which are generally ascribed to a sudden increase of mass accretion rate in the surrounding protostellar disc. Models invoking a thermal instability in the disc are able to reproduce many features of the outburst, but cannot explain the rapid rise time-scale observed in many cases. Here we explore the possibility (originally suggested by Clarke & Syer 1996) that the thermal instability is triggered away from the disc inner edge (at a distance of $\\approx 10R_{\\odot}$ from the central protostar) due to the presence of a massive planet embedded in the disc. We have constructed simple, one-dimensional, time-dependent models of the disc evolution, taking into account both the interaction between the disc and the planet, and the thermal evolution of the disc. We are indeed able to reproduce rapid rise outbursts (with rise time-scale $\\approx 1$ yr), with a planet mass $M_{\\mathrm{s}}=10-15M_{\\mathrm{Jupiter}}$. We show that the luminosity and the duration of the outbursts are increasing functions of planet mass. We also show that the inward migration of the planet is significantly slowed once it reaches the radius where it is able to trigger FU Orionis outbursts, thus suggesting that a single planet may be involved in triggering several outbursts.
G. Lodato; C. J. Clarke
Maximally Random Jamming of Two-Dimensional One-Component and Binary Hard Disc Fluids
We report calculations of the density of maximally random jamming (aka random close packing) of one-component and binary hard disc fluids. The theoretical structure used provides a common framework for description of the hard disc liquid to hexatic, the liquid to hexagonal crystal and the liquid-to-maximally random jammed state transitions. Our analysis is based on locating a particular bifurcation of the solutions of the integral equation for the inhomogeneous single particle density at the transition between different spatial structures. The bifurcation of solutions we study is initiated from the dense metastable fluid, and we associate it with the limit of stability of the fluid, which we identify with the transition from the metastable fluid to a maximally random jammed state. For the one-component hard disc fluid the predicted packing fraction at which the metastable fluid to maximally random jammed state transition occurs is 0.84, in excellent agreement with the experimental value 0.84 \\pm 0.02. The corresponding analysis of the limit of stability of a binary hard disc fluid with specified disc diameter ratio and disc composition requires extra approximations in the representations of the direct correlation function, the equation of state, and the number of order parameters accounted for. Keeping only the order parameter identified with the largest peak in the structure factor of the highest density regular lattice with the same disc diameter ratio and disc composition as the binary fluid, the predicted density of maximally random jamming is found to be 0.84 to 0.87, depending on the equation of state used, and very weakly dependent on the ratio of disc diameters and the fluid composition, in agreement with both experimental data and computer simulation data.
Xinliang Xu; Stuart A. Rice
Cavity opening by a giant planet in a protoplanetary disc and effects on planetary migration
We study the effect of a Jovian planet on the gas distribution of a protoplanetary disc, using a new numerical scheme that allows us to take into consideration the global evolution of the disc, down to an arbitrarily small inner physical radius. We find that Jovian planets do not open cavities in the inner part of the disc (i.e. interior to their orbits) unless (a) the inner physical edge of the disc is close to the planet's location or (b) the planet is much more massive than the disc. In all other cases the planet simply opens a gap in the gas density distribution, whose global profile is essentially unchanged relative to the one that it would have if the planet were absent. We recognize, though, that the dust distribution can be significantly different from the gas distribution and that dust cavities might be opened in some situations, even if the gas is still present in the inner part of the disc. Concerning the migration of the planet, we find that classical Type-II migration (with speed proportional to the viscosity of the disc) occurs only if the gap opened by the planet is deep and clean. If there is still a significant amount of gas in the gap, the migration of the planet is generally slower than the theoretical Type-II migration rate. In some situations, migration can be stopped or even reversed. We develop a simple model that reproduces satisfactorily the migration rate observed in the simulations, for a wide range of disc viscosities and planet masses and locations relative to the inner disc edge. Our results are relevant for extra-solar planetary systems, as they explain (a) why some hot Jupiters did not migrate all the way down to their parent stars and (b) why the outermost of a pair of resonant planets is typically the most massive one.
A. Crida; A. Morbidelli
Eccentricity growth of planetesimals in a self-gravitating protoplanetary disc
We investigate the orbital evolution of planetesimals in a self-gravitating circumstellar disc in the size regime ($\\sim 1-5000$ km) where the planetesimals behave approximately as test particles in the disc's non-axisymmetric potential. We find that the particles respond to the stochastic, regenerative spiral features in the disc by executing large random excursions (up to a factor of two in radius in $\\sim 1000$ years), although typical random orbital velocities are of order one tenth of the Keplerian speed. The limited time frame and small number of planetesimals modeled does not permit us to discern any {\\it net} direction of planetesimal migration. Our chief conclusion is that the high eccentricities ($\\sim 0.1$) induced by interaction with spiral features in the disc is likely to be highly unfavourable to the collisional growth of planetesimals in this size range while the disc is in the self-gravitating regi me. Thus {\\it if}, as recently argued by Rice et al 2004, 2006, the production of planetesimals gets under way when the disc is in the self-gravitating regime (either at smaller planetesimal size scales, where gas drag is important, or via gravitational fragmentation of the solid component), then the planetesimals thus produced would not be able to grow collisionally until the disc ceased to be self-gravitating. It is unclear, however,given the large amplitude excursions undergone by planetesimals in the self-gravitating disc, whether they would be retained in the disc throughout this period, or whether they would instead be lost to the central star.
M. Britsch; C. J. Clarke; G. Lodato
An analysis of the annual probability of failure of the waste hoist brake system at the Waste Isolation Pilot Plant (WIPP)
The Environmental Evaluation Group (EEG) previously analyzed the probability of a catastrophic accident in the waste hoist of the Waste Isolation Pilot Plant (WIPP) and published the results in Greenfield (1990; EEG-44) and Greenfield and Sargent (1993; EEG-53). The most significant safety element in the waste hoist is the hydraulic brake system, whose possible failure was identified in these studies as the most important contributor in accident scenarios. Westinghouse Electric Corporation, Waste Isolation Division has calculated the probability of an accident involving the brake system based on studies utilizing extensive fault tree analyses. This analysis conducted for the U.S. Department of Energy (DOE) used point estimates to describe the probability of failure and includes failure rates for the various components comprising the brake system. An additional controlling factor in the DOE calculations is the mode of operation of the brake system. This factor enters for the following reason. The basic failure rate per annum of any individual element is called the Event Probability (EP), and is expressed as the probability of failure per annum. The EP in turn is the product of two factors. One is the {open_quotes}reported{close_quotes} failure rate, usually expressed as the probability of failure per hour and the other is the expected number of hours that the element is in use, called the {open_quotes}mission time{close_quotes}. In many instances the {open_quotes}mission time{close_quotes} will be the number of operating hours of the brake system per annum. However since the operation of the waste hoist system includes regular {open_quotes}reoperational check{close_quotes} tests, the {open_quotes}mission time{close_quotes} for standby components is reduced in accordance with the specifics of the operational time table.
Greenfield, M.A. [Univ. of California, Los Angeles, CA (United States); Sargent, T.J.
Design and test of a wet type helium turbo-expander with an alternator as a brake
A wet type helium turbo-expander with expected adiabatic efficiency of 70% at inlet pressure, temperature, and outlet pressure of 1.3 MPa, 6.0 K, and 0.2 MPa, respectively, has been developed. An alternator is adopted as a brake where a permanent magnet is held in the turbine shaft. And a self-acting gas bearing is used at thrust and journal bearings. An electromagnet supports thrust bearing to lift up the thrust disk when initiating operation. Design mass flow rate of the turbine is determined to be 60 g/s, corresponding to the JT mass flow rate in the existing helium liquefier/refrigerator. In the cryogenic performance test, the turbine had increased helium liquefaction rate by four times larger than the liquefaction rate without turbine operation.
Kato, T.; Miyake, A.; Kawano, K.; Hamada, K.; Hiyama, T.; Iwamoto, S.; Ebisu, H.; Tsuji, H. [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan); Saji, N.; Kaneko, Y. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)] [and others
Methods for enhancing mapping of thermal fronts in oil recovery
A method for enhancing the resistivity contrasts of a thermal front in an oil recovery production field as measured by the CSAMT technique is disclosed. This method includes the steps of: (a) preparing a CSAMT-determined topological resistivity map of the production field; (b) introducing a solution of a dopant material into the production field at a concentration effective to alter the resistivity associated with the thermal front; said dopant material having a high cation exchange capacity which might be selected from the group consisting of montmorillonite, illite, and chlorite clays; said material being soluble in the connate water of the production field; (c) preparing a CSAMT-determined topological resistivity map of the production field while said dopant material is moving therethrough; and (d) mathematically comparing the maps from step (a) and step (c) to determine the location of the thermal front. This method is effective with the steam flood, fire flood and water flood techniques.
Lee, David O. (Albuquerque, NM); Montoya, Paul C. (Albuquerque, NM); Wayland, Jr., James R. (Albuquerque, NM)
Acoustic wave front reversal in a three-phase media
Acoustic wave front conjugation is studied in a sandy marine sediment that contains air bubbles in its fluid fraction. The considered phase conjugation is a four-wave nonlinear parametric sound interaction process caused by nonlinear bubble oscillations which are known to be dominant in acoustic nonlinear interactions in three-phase marine sediments. Two various mechanisms of phase conjugation are studied. One of them is based on the stimulated Raman-type sound scattering on resonance bubble oscillations. The second one is associated with sound interactions with bubble oscillations which frequencies are far from resonance bubble frequencies. Nonlinear equations to solve the wave-front conjugation problem are derived, expressions for acoustic wave amplitudes with a reversed wave front are obtained and compared for various frequencies of the excited bubble oscillations.
N. I. Pushkina
Acoustic wave front conjugation in a three-phase media
Acoustic wave front reversal is studied in a sandy marine sediment that contains air bubbles in its fluid fraction. The considered phase conjugation is a four-wave nonlinear parametric sound interaction process caused by nonlinear bubble oscillations which are known to be dominant in acoustic nonlinear interactions in three-phase marine sediments. Two various mechanisms of phase conjugation are studied. One of them is based on the stimulated Raman-type sound scattering on resonance bubble oscillations. The second one is associated with sound interactions with bubble oscillations which frequencies are far from resonance bubble frequencies. Nonlinear equations to solve the wave-front conjugation problem are derived, expressions for acoustic wave amplitudes with a reversed wave front are obtained and compared for various frequencies of the excited bubble oscillations.
Pushkina, N I
A method for enhancing the resistivity contrasts of a thermal front in an oil recovery production field as measured by the controlled source audio frequency magnetotelluric (CSAMT) technique is disclosed. This method includes the steps of: (1) preparing a CSAMT-determined topological resistivity map of the production field; (2) introducing a solution of a dopant material into the production field at a concentration effective to alter the resistivity associated with the thermal front; said dopant material having a high cation exchange capacity which might be selected from the group consisting of montmorillonite, illite, and chlorite clays; said material being soluble in the conate water of the production field; (3) preparing a CSAMT-determined topological resistivity map of the production field while said dopant material is moving therethrough; and (4) mathematically comparing the maps from step (1) and step (3) to determine the location of the thermal front. This method is effective with the steam flood, fire flood and water flood techniques.
Lee, D.O.; Montoya, P.C.; Wayland, J.R. Jr.
Light-Front Holography and Non-Perturbative QCD
The combination of Anti-de Sitter space (AdS) methods with light-front holography leads to a semi-classical first approximation to the spectrum and wavefunctions of meson and baryon light-quark bound states. Starting from the bound-state Hamiltonian equation of motion in QCD, we derive relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. Its eigenvalues give the hadronic spectrum, and its eigenmodes represent the probability distribution of the hadronic constituents at a given scale. Applications to the light meson and baryon spectra are presented. The predicted meson spectrum has a string-theory Regge form M{sup 2} = 4{kappa}{sup 2}(n + L + S = 2); i.e., the square of the eigenmass is linear in both L and n, where n counts the number of nodes of the wavefunction in the radial variable {zeta}. The space-like pion form factor is also well reproduced. One thus obtains a remarkable connection between the description of hadronic modes in AdS space and the Hamiltonian formulation of QCD in physical space-time quantized on the light-front at fixed light-front time {tau}. The model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms.
Brodsky, Stanley J.; /SLAC; de Teramond, Guy F.; /Costa Rica U.
Light-Front Holographic QCD and Emerging Confinement
In this report we explore the remarkable connections between light-front dynamics, its holographic mapping to gravity in a higher-dimensional anti-de Sitter (AdS) space, and conformal quantum mechanics. This approach provides new insights into the origin of a fundamental mass scale and the physics underlying confinement dynamics in QCD in the limit of massless quarks. The result is a relativistic light-front wave equation for arbitrary spin with an effective confinement potential derived from a conformal action and its embedding in AdS space. This equation allows for the computation of essential features of hadron spectra in terms of a single scale. The light-front holographic methods described here gives a precise interpretation of holographic variables and quantities in AdS in terms of light-front variables and quantum numbers. This leads to a relation between the AdS wave functions and the boost-invariant light-front wave functions describing the internal structure of hadronic bound states in physical space-time. The pion is massless in the chiral limit and the excitation spectra of relativistic light-quark meson and baryon bound states lie on linear Regge trajectories with identical slopes in the radial and orbital quantum numbers. In the light-front holographic approach described here currents are expressed as an infinite sum of poles, and form factors as a product of poles. At large $q^2$ the form factor incorporates the correct power-law fall-off for hard scattering independent of the specific dynamics and is dictated by the twist. At low $q^2$ the form factor leads to vector dominance. The approach is also extended to include small quark masses. We briefly review in this report other holographic approaches to QCD, in particular top-down and bottom-up models based on chiral symmetry breaking. We also include a discussion of open problems and future applications.
Stanley J. Brodsky; Guy F. de Teramond; Hans Gunter Dosch; Joshua Erlich
Retinal imaging tool for assessment of the parapapillary atrophy and the optic disc�
Ophthalmic diseases such as glaucoma are associated with progressive changes in the structure of the optic disc (OD) and parapapillary atrophy (PPA). These structural changes may therefore have relevance to other systemic ...
Lu, Cheng-Kai
E-Print Network 3.0 - agn accretion disc Sample Search Results
of the system in the slow accretion limit. The disc structure is distinct... of the wind, which implies a higher accretion rate at those regions. In ... Source: Dublin City...
E-Print Network 3.0 - accretion discs ii Sample Search Results
disc surface when it is irradiatively heated by soft X-rays. Single-peaked lines... inclination is about 158 if the orbital period is 14.8 h. Key words: accretion, accretion...
E-Print Network 3.0 - accretion disc boundary Sample Search Results
E-Print Network 3.0 - accretion disc viewed Sample Search Results
370, L61L65 (2006) doi:10.1111j.1745-3933.2006.00189.x The late time evolution of gamma-ray bursts: ending hyperaccretion Summary: of GRBs. Key words: accretion, accretion discs -...
E-Print Network 3.0 - accretion disc outflows Sample Search Results
E-Print Network 3.0 - accretion disc origin Sample Search Results
E-Print Network 3.0 - accretion disc variability Sample Search...
E-Print Network 3.0 - accretion disc theory Sample Search Results
Spectral Evolution of the Continuum and Disc Line in Dipping in GRO J1655-40
The discovery is reported of emission features in the X-ray spectrum of GRO J1655-40 obtained using Rossi-XTE on 1997, Feb 26. The features have been fitted firstly by two Gaussian lines, which in four spectra have average energies of 5.85+/-0.08 keV and 7.32+/-0.13 keV, strongly suggestive that these are the red- and blueshifted wings of an iron disc line from material with velocity ~0.33 c. The blue wing is apparently less bright than expected for a disc line subject to Doppler boosting, however, known absorption in the spectrum of GRO J1655-40 at energies between ~7 and 8 keV can reduce the apparent brightness of the blue wing. The spectra have also been fitted well using the full relativistic disc line model of Laor, plus an absorption line. This gives a restframe energy between 6.4 and 6.8 keV indicating that the line is from highly ionized iron K_alpha. The Laor model also shows that the line originates at radii extending from ~10 Schwarzschild radii (r_S) outwards. The line is direct evidence for the black hole nature of the compact object. The continuum is well described by dominant disc blackbody emission plus Comptonized emission. During dipping, spectral evolution is well modelled by allowing progressive covering of the disc blackbody and simple absorption of the Comptonized emission showing that the thermal emission is more extended. Acceptable fits are only obtained by including the disc line in the covering term, indicating that it originates in the same inner disc region as the thermal continuum. Dip ingress times and durations are used to provide the radius of the disc blackbody emitter as 170-370 r_S, and the radius of the absorber.
M. Balucinska-Church
Secular resonant dressed orbital diffusion II : application to an isolated self similar tepid galactic disc
The main orbital signatures of the secular evolution of an isolated self-gravitating stellar Mestel disc are recovered using a dressed Fokker-Planck formalism in angle-action variables. The shot-noise-driven formation of narrow ridges of resonant orbits is recovered in the WKB limit of tightly wound transient spirals, for a tepid Toomre-stable tapered disc. The relative effect of the bulge, the halo, the disc temperature and the spectral properties of the shot noise are investigated in turn. For such galactic discs all elements seem to impact the locus and direction of the ridge. For instance, when the halo mass is decreased, we observe a transition between a regime of heating in the inner regions of the disc through the inner Lindblad resonance to a regime of radial migration of quasi-circular orbits via the corotation resonance in the outer part of the disc. The dressed secular formalism captures both the nature of collisionless systems (via their natural frequencies and susceptibility), and their nurture v...
Fouvry, Jean-Baptiste
Development of RF CMOS receiver front-ends for ultrawideband
demonstrates two different solutions for the RF front-end designs in the UWB receivers, one is distributed topology, and the other is based on traditional lumped element topology. The distributed amplifier is one of the attractive candidates for UWB Low Noise...
Guan, Xin
Neutrino factory front-end: muon capture and cooling optimization
The neutrino factory is one of the designs proposed for a future intense neutrino beam facility. The layout discussed here focuses on the front-end of the current baseline. The challenges inherent to the cooling of muons are shown together with possible baseline optimization.
Prior, G
INTERNAL GRAVITY WAVES FROM ATMOSPHERIC JETS AND FRONTS Riwal Plougonven1 and Fuqing Zhang2 consistently highlighted jet exit regions as a favored locus for intense gravity waves, the mechanisms need for improving parameterizations of nonorographic gravity waves in climate models that include
Plougonven, Riwal
Geodesic Remeshing Using Front Propagation Gabriel Peyre Laurent Cohen
Geodesic Remeshing Using Front Propagation Gabriel Peyr´e Laurent Cohen CMAP CEREMADE, UMR CNRS, we present a method for remeshing trian- gulated manifolds by using geodesic path calculations is automatically found. A geodesic Delaunay triangulation of the set of points is then created, using a Voronoi
A FRONT TRACKING METHOD FOR TRANSITIONAL SHOCK WAVES HYUNCHEOL HWANG Abstract. Non of transitional shock waves, which are dependent on the parabolic regularization of the conservation laws transitional shock waves correctly. The algorithm includes the computation of saddletosaddle connec tions
New York at Stoney Brook, State University of
Utility theory front to back inferring utility from agents' choices
Utility theory front to back inferring utility from agents' choices A. M. G. Cox Dept to utility theory and consumption & investment problems. Instead of specifying an agent's utility function) and ask if it is possible to derive a utility function for which the observed behaviour is optimal. We
Actin polymerization front propagation in a comb-reaction system
Anomalous transport and reaction dynamics are considered by providing the theoretical grounds for the possible experimental realization of actin polymerization in comb-like geometry. Two limiting regimes are recovered, depending on the concentration of reagents (magnesium and actin). These are both the failure of the reaction front propagation and a finite speed corresponding to the Fisher-KPP long time asymptotic regime.
Iomin, A; Pfohl, T
Front and backside processed thin film electronic devices
This invention provides thin film devices that have been processed on their front- and backside. The devices include an active layer that is sufficiently thin to be mechanically flexible. Examples of the devices include back-gate and double-gate field effect transistors, double-sided bipolar transistors and 3D integrated circuits.
Evans, Paul G. (Madison, WI); Lagally, Max G. (Madison, WI); Ma, Zhenqiang (Middleton, WI); Yuan, Hao-Chih (Lakewood, CO); Wang, Guogong (Madison, WI); Eriksson, Mark A. (Madison, WI)
This invention provides methods for fabricating thin film electronic devices with both front- and backside processing capabilities. Using these methods, high temperature processing steps may be carried out during both frontside and backside processing. The methods are well-suited for fabricating back-gate and double-gate field effect transistors, double-sided bipolar transistors and 3D integrated circuits.
Yuan, Hao-Chih (Madison, WI); Wang, Guogong (Madison, WI); Eriksson, Mark A. (Madison, WI); Evans, Paul G. (Madison, WI); Lagally, Max G. (Madison, WI); Ma, Zhenqiang (Middleton, WI)
Flame front tracking by laser induced fluorescence spectroscopy and advanced
surface characteristics in turbulent premixed propane/air combustion," Combustion and Flame 120(4), 407 References and links 1. J. Warnatz, U. Maas, and R.W. Dibble, Combustion - physical and chemical fundamentals, "Characterization of flame front surfaces in turbulent premixed methane/air combustion," Combustion and Flame 101
Hamarneh, Ghassan
Front Vehicle Blind Spot Translucentization Based on Augmented Reality
Front Vehicle Blind Spot Translucentization Based on Augmented Reality Che-Tsung Lin, Yu-Chen Lin--Recently, WAVE/DSRC has become an attrac- tive technology for vehicular safety applications. Vehicles with WAVE/DSRC devices can communicate with their neighboring vehicles to exchange information to achieve collaborative
Wang, Yuan-Fang
Multimaterial Front Tracking Fang Da, Christopher Batty, and Eitan Grinspun
.8 [Simulation and Modeling]: Types of Simulation--Animation Additional Key Words and Phrases: front tracking. Numerous additional physical and mathemat- ical applications have this same form: soap bubbles and dry the space of possible entangled mesh configurations that can arise, and topological transformations
The effects of X-ray photoionization and heating on the structure of circumstellar discs
We present the results of a theoretical study investigating the effects of photoionization and heating by X-rays on discs around low-mass stars. In particular we address the question of whether or not X-rays can drive a disc wind. First, we construct a 1-dimensional ``quasi-hydrostatic'' model, which solves for the vertical structure introduced by X-ray heating. We consider uniform X-ray illumination of the disc, but the X-ray fluxes required to heat the disc significantly are much greater than those seen by recent observations. When the model is extended to consider heating from a central X-ray source we find that the 1-dimensional model is only valid very close to the star. We extend our analysis to consider a simple 2-dimensional model, treating the disc as a two-layered structure and solving for its density profile self-consistently. For T Tauri stars we are able to set a crude upper limit on the mass-loss rate that can be driven by X-ray photoevaporation, with a value of ~10^-13 g/cm^2/s. Our model is designed to maximise this value, and most likely over-estimates it significantly. However we still find a mass-loss rate which is less than that found in studies of ultraviolet photoevaporation. We conclude that in the presence of a significant UV field, X-ray driven disc winds are unlikely to play a significant role in the evolution of discs around low-mass stars.
Improved Reliability of PV Modules with Lexan PC Sheet-Front...
Improved Reliability of PV Modules with Lexan PC Sheet-Front Sheet, Noryl PPE Sheet-Back Sheet Improved Reliability of PV Modules with Lexan PC Sheet-Front Sheet, Noryl PPE...
IMPROVED RELIABILITY OF PV MODULES WITH LEXAN(tm) (PC ) SHEET - FRONT SHEET NORYL(tm) (PPE) SHEET - BACK SHEET NORYL(tm) Sheet for back sheet application LEXAN(tm) sheet for front...
E-Print Network 3.0 - adaptive optics wave-front Sample Search...
Powered by Explorit Topic List Advanced Search Sample search results for: adaptive optics wave-front Page: << < 1 2 3 4 5 > >> 1 Wave-front generation of Zernike polynomial...
Galaxy Zoo and ALFALFA: Atomic Gas and the Regulation of Star Formation in Barred Disc Galaxies
We study the observed correlation between atomic gas content and the likelihood of hosting a large scale bar in a sample of 2090 disc galaxies. Such a test has never been done before on this scale. We use data on morphologies from the Galaxy Zoo project and information on the galaxies' HI content from the ALFALFA blind HI survey. Our main result is that the bar fraction is significantly lower among gas rich disc galaxies than gas poor ones. This is not explained by known trends for more massive (stellar) and redder disc galaxies to host more bars and have lower gas fractions: we still see at fixed stellar mass a residual correlation between gas content and bar fraction. We discuss three possible causal explanations: (1) bars in disc galaxies cause atomic gas to be used up more quickly, (2) increasing the atomic gas content in a disc galaxy inhibits bar formation, and (3) bar fraction and gas content are both driven by correlation with environmental effects (e.g. tidal triggering of bars, combined with strangu...
Masters, Karen L; Haynes, Martha P; Keel, William C; Lintott, Chris; Simmons, Brooke; Skibba, Ramin; Bamford, Steven; Giovanelli, Riccardo; Schawinski, Kevin
Licensing Uncertain Patents: Per-Unit Royalty vs. Up-Front Fee
Licensing Uncertain Patents: Per-Unit Royalty vs. Up-Front Fee David Encaouay and Yassine Lefouiliz schemes are investigated: the per-unit royalty rate and the up-front fee. We provide conditions under-unit royalty scheme, the opportunity to do so does not exist under the up-front fee scheme. We also establish
Boyer, Edmond
Introduction Idealized Moist Jet/Front Waves Ray Tracing Momentum Flux/Forcing Conclusion Gravity Waves
Introduction Idealized Moist Jet/Front Waves Ray Tracing Momentum Flux/Forcing Conclusion Gravity Waves in Moist Baroclinic Jet-Front Systems Junhong Wei, Fuqing Zhang Department of Meteorology The Pennsylvania State University Tuesday 19th August, 2014 #12;Introduction Idealized Moist Jet/Front Waves Ray
Thompson, Anne
Massively Parallel Computation of Sti Propagating Combustion frontsMarc Garbey and Damien Tromeur-Dervout
In this paper we study the computation of combustion fronts using MIMD archi- tecture. Our applications in gas models of combustion fronts: rst, a classical thermo-di usive model describing the combustion of a gasMassively Parallel Computation of Sti Propagating Combustion frontsMarc Garbey and Damien Tromeur
Garbey, Marc
Physics design of front ends for superconducting ion linacs
Superconducting (SC) technology is the only option for CW linacs and is also an attractive option for pulsed linacs. SC cavities are routinely used for proton and H{sup -} beam acceleration above 185 MeV. Successful development of SC cavities covering the lower velocity range (down to 0.03c) is a very strong basis for the application of SC structures in the front ends of high energy linacs. Lattice design and related high-intensity beam physics issues in a {approx}400 MeV linac that uses SC cavities will be presented in this talk. In particular, axially-symmetric focusing by SC solenoids provides strong control of beam space-charge and a compact focusing lattice. As an example, we discuss the SC front-end of the H{sup -} linac for the FNAL Proton Driver.
Ostroumov, P.N.; /Argonne; Carneiro, J.P.; /Fermilab
Superconducting (SC) technology is the only option for CW linacs and is also an attractive option for pulsed linacs. SC cavities are routinely used for proton and H{sup -} beam acceleration above 185 MeV. Successful development of SC cavities covering the lower velocity range (down to 0.03c) is a very strong basis for the application of SC structures in the front ends of high energy linacs. Lattice design and related high-intensity beam physics issues in a {approx}400 MeV linac that uses SC cavities will be presented in this talk. In particular, axially-symmetric focusing by SC solenoids provides strong control of beam space charge and a compact focusing lattice. As an example, we discuss the SC front end of the H{sup -} linac for the FNAL Proton Driver.
Ostroumov, P.N.; /Argonne; Carneiro, J.-P.; /Fermilab
Tracking thermal fronts with temperature-sensitive, chemically reactive tracers
Los Alamos is developing tracer techniques using reactive chemicals to track thermal fronts in fractured geothermal reservoirs. If a nonadsorbing tracer flowing from the injection to production well chemically reacts, its reaction rate will be a strong function of temperature. Thus the extent of chemical reaction will be greatest early in the lifetime of the system, and less as the thermal front progresses from the injection to production well. Early laboratory experiments identified tracers with chemical kinetics suitable for reservoirs in the temperature range of 75 to 100/sup 0/C. Recent kinetics studies have focused on the kinetics of hydrolysis of derivatives of bromobenzene. This class of reactions can be used in reservoirs ranging in temperature from 150 to 275/sup 0/C, which is of greater interest to the geothermal industry. Future studies will include laboratory adsorption experiments to identify possibly unwanted adsorption on granite, development of sensitive analytical techniques, and a field demonstration of the reactive tracer concept.
Robinson, B.A.; Birdsell, S.A.
Ionization front-driven turbulence in the clumpy interstellar medium
We present 3D radiation-gasdynamical simulations of an ionization front running into a dense clump. In our setup, a B0 star irradiates an overdensity which is at a distance of 10 pc and modelled as a supercritical 100 M_sol Bonnor-Ebert sphere. The radiation from the star heats up the gas and creates a shock front that expands into the interstellar medium. The shock compresses the clump material while the ionizing radiation heats it up. The outcome of this "cloud-crushing" process is a fully turbulent gas in the wake of the clump. In the end, the clump entirely dissolves. We propose that this mechanism is very efficient in creating short-living supersonic turbulence in the vicinity of massive stars.
Thomas Peters; Robi Banerjee; Ralf S. Klessen
Towards the Light Front Variables for High Energy Production Processes
Scale invariant presentation of inclusive spectra in terms of light front variables is proposed. The variables introduced go over to the well-known scaling variables x_F = 2p_z/sqrt(s) and x_T=2p_T/sqrt{s} in the high p_z and high p_T limits respectively. So Some surface is found in the phase space of produced pi-mesons in the inclusive reaction anti p p -> pi+- X at 22.4 GeV/c, which separates two groups of particles with significantly different characteristics. In one of these regions a naive statistical model seems to be in a good agreement with data, whereas it fails in the second region. Key words: Light front, inclusive, hadron-hadron, electron-positron, relativistic heavy ions, deep inelastic.
N. S. Amaglobeli; S. M. Esakia; V. R. Garsevanishvili; G. O. Kuratashvili; N. K. Kutsidi; R. A. Kvatadze; Yu V. Tevzadze; T. P. Topuria
Epidemic fronts in complex networks with metapopulation structure
Infection dynamics have been studied extensively on complex networks, yielding insight into the effects of heterogeneity in contact patterns on disease spread. Somewhat separately, metapopulations have provided a paradigm for modeling systems with spatially extended and "patchy" organization. In this paper we expand on the use of multitype networks for combining these paradigms, such that simple contagion models can include complexity in the agent interactions and multiscale structure. We first present a generalization of the Volz-Miller mean-field approximation for Susceptible-Infected-Recovered (SIR) dynamics on multitype networks. We then use this technique to study the special case of epidemic fronts propagating on a one-dimensional lattice of interconnected networks - representing a simple chain of coupled population centers - as a necessary first step in understanding how macro-scale disease spread depends on micro-scale topology. Using the formalism of front propagation into unstable states, we derive ...
Hindes, Jason; Myers, Christopher R; Schneider, David J
Amaglobeli, N S; Garsevanishvili, V R; Kuratashvili, G O; Kutsidi, N K; Kvatadze, R A; Tevzadze, Yu V; Topuria, T P; Tevzadze, Yu V.
Adaptive two-regime method: Application to front propagation
The Adaptive Two-Regime Method (ATRM) is developed for hybrid (multiscale) stochastic simulation of reaction-diffusion problems. It efficiently couples detailed Brownian dynamics simulations with coarser lattice-based models. The ATRM is a generalization of the previously developed Two-Regime Method [Flegg et al., J. R. Soc., Interface 9, 859 (2012)] to multiscale problems which require a dynamic selection of regions where detailed Brownian dynamics simulation is used. Typical applications include a front propagation or spatio-temporal oscillations. In this paper, the ATRM is used for an in-depth study of front propagation in a stochastic reaction-diffusion system which has its mean-field model given in terms of the Fisher equation [R. Fisher, Ann. Eugen. 7, 355 (1937)]. It exhibits a travelling reaction front which is sensitive to stochastic fluctuations at the leading edge of the wavefront. Previous studies into stochastic effects on the Fisher wave propagation speed have focused on lattice-based models, but there has been limited progress using off-lattice (Brownian dynamics) models, which suffer due to their high computational cost, particularly at the high molecular numbers that are necessary to approach the Fisher mean-field model. By modelling only the wavefront itself with the off-lattice model, it is shown that the ATRM leads to the same Fisher wave results as purely off-lattice models, but at a fraction of the computational cost. The error analysis of the ATRM is also presented for a morphogen gradient model.
Robinson, Martin, E-mail: email@example.com; Erban, Radek, E-mail: email@example.com [Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG (United Kingdom)] [Mathematical Institute, University of Oxford, Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford OX2 6GG (United Kingdom); Flegg, Mark, E-mail: firstname.lastname@example.com [School of Mathematical Sciences, Faculty of Science, Monash University Wellington Road, Clayton, Victoria 3800 (Australia)] [School of Mathematical Sciences, Faculty of Science, Monash University Wellington Road, Clayton, Victoria 3800 (Australia)
A turnstile mechanism for fronts propagating in fluid flows
We consider the propagation of fronts in a periodically driven flowing medium. It is shown that the progress of fronts in these systems may be mediated by a turnstile mechanism akin to that found in chaotic advection. We first define the modified ("active") turnstile lobes according to the evolution of point sources across a transport boundary. We then show that the lobe boundaries may be constructed from stable and unstable \\emph{burning invariant manifolds}---one-way barriers to front propagation analogous to traditional invariant manifolds for passive advection. Because the burning invariant manifolds (BIMs) are one-dimensional curves in a three-dimensional ($xy\\theta$) phase space, their projection into $xy$-space exhibits several key differences from their advective counterparts: (lobe) areas are not preserved, BIMs may self-intersect, and an intersection between stable and unstable BIMs does not map to another such intersection. These differences must be accommodated in the correct construction of the new turnstile. As an application, we consider a lobe-based treatment protocol for protecting an ocean bay from an invading algae bloom.
John R. Mahoney; Kevin A. Mitchell
A Life Cycle Assessment of a Magnesium Automotive Front End
The Magnesium Front End Research and Development (MFERD) project under the sponsorship of Canada, China and USA aims to develop key technologies and a knowledge base for increased use of magnesium in automobile. The goal of this life cycle assessment (LCA) study is to compare the energy and potential environmental impacts of advanced magnesium based front end parts of a North America built 2007 GM-Cadillac CTS with the standard carbon steel based design. This LCA uses the 'cradle-to-grave' approach by including primary material production, semi-fabrication production, autoparts manufacturing and assembly, transportation, use phase and end-of-life processing of autoparts. This LCA study was done in compliance with international standards ISO 14040:2006 and ISO 14044:2006. Furthermore, the LCA results for aluminum based front end autopart are presented. While weight savings result in reductions in energy use and carbon dioxide emissions during the use of the car, the impacts of fabrication and recycling of lightweight materials are substantial in regard to steel. Pathways for improving sustainability of magnesium use in automobiles through material management and technology improvements including recycling are also discussed.
Das, Sujit [ORNL; Dubreuil, Alain [Natural Resources Canada; Bushi, Lindita [GreenhouseGasMeasurement.com; Tharumarajah, Ambalavanar [CSIRO/CAST-CRC
Magnetic Turbulence and Thermodynamics in the Inner Region of Protoplanetary Discs
Using radiation magnetohydrodynamics simulations with realistic opacities and equation of state, and zero net magnetic flux, we have explored thermodynamics in the inner part of protoplanetary discs where magnetic turbulence is expected. The thermal equilibrium curve consists of the upper, lower, and middle branches. The upper (lower) branch corresponds to hot (cool) and optically very (moderately) thick discs, respectively, while the middle branch is characterized by convective energy transport near the midplane. Convection is also the major energy transport process near the low surface density end of the upper branch. There, convective motion is fast with Mach numbers reaching $\\gtrsim 0.01$, and enhances both magnetic turbulence and cooling, raising the ratio of vertically-integrated shear stress to vertically-integrated pressure by a factor of several. This convectively enhanced ratio seems a robust feature in accretion discs having an ionization transition. We have also examined causes of the S-shaped th...
Hirose, Shigenobu
W.C. Heraeus GmbH and its activities regarding large grain Niobium Discs
W.C. Heraeus is one of the leading companies in the field of precious and refractory metals. The refractory metals activities have been started in 1940. W.C. Heraeus is one of the qualified suppliers for high pure Niobium for the use in high-frequency-super-conducting cavities. The latest activities in that field are the development of a stable Electron-Beam-Melting and reliable cutting processes to produce large grain Niobium discs directly cut from the Ingot in an industrial scale. The first cavities out of these discs have been tested and are showing excellent magnetic properties.
Spaniol, Bernd [W.C.Heraeus GmbH, Engineered Material Division, Heraeusstrasse 12-14, 63450 Hanau (Germany)
A study of the contrast of a submerged disc using Monte Carlo techniques
A STUDY OF THE CONTRAST OF A SUBMERGED DISC USING MONTE CARLO TECHNIQUES A Thesis by DONALD FRANK HAGAN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1980 Major Subject: Physics A STUDY OF THE CONTRAST OF A SUBMERGED DISC USING MONTE CARLO TECHNIQUES A Thesis by DONALD FRANK HAGAN Approved as to sty1e and content by: (Chairman of Committee) (Head of Department) (Member) (Member...
Hagan, Donald Frank
Discrete Mathematics 233 (2001) 175182 www.elsevier.com/locate/disc
Discrete Mathematics 233 (2001) 175182 www.elsevier.com/locate/disc Some remarks on cycles on cycles of graphs and directed graphs of the following form: `Does there exist a set of cycles with a property P that generates all the cycles by operation O?'. c 2001 Published by Elsevier Science B.V. 1
Matamala, Martín
X-ray variability of SS433: effects of the supercritical accretion disc
We study a stochastic variability of SS433 in the $10^{-4} - 5\\times 10^{-2}$ Hz frequency range based on RXTE data, and on simultaneous observations with RXTE and optical telescopes. We find that the cross-correlation functions and power spectra depend drastically on the precession phase of the supercritical accretion disc. When the wind funnel of the disc is maximally open to the observer, a flat part emerges in the power spectrum; a break is observed at the frequency $1.7\\times10^{-3}$ Hz, with a power-law index $\\beta \\approx 1.67$ at higher frequencies. The soft emission forming mostly in the jets, lags behind the hard and optical emission. When the observer does not see the funnel and jets (the `edge-on' disc), the power spectrum is described by a single power-law with $\\beta \\approx 1.34$ and no correlations between X-ray ranges are detected. We investigated two mechanisms to explain the observed variability at the open disc phase, 1) reflection of radiation at the funnel wall (X-rays and optical) and ...
Atapin, Kirill; Medvedev, Aleksei; Vinokurov, Alexander
Searching for signatures of planet formation in stars with circumstellar debris discs
(Abridged) Tentative correlations between the presence of dusty debris discs and low-mass planets have been presented. In parallel, detailed chemical abundance studies have reported different trends between samples of planet and non-planet hosts. We determine in a homogeneous way the metallicity, and abundances of a sample of 251 stars including stars with known debris discs, with debris discs and planets, and only with planets. Stars with debris discs and planets have the same [Fe/H] behaviour as stars hosting planets, and they also show a similar -Tc trend. Different behaviour in the -Tc trend is found between the samples of stars without planets and the samples of planet hosts. In particular, when considering only refractory elements, negative slopes are shown in cool giant planet hosts, whilst positive ones are shown in stars hosting low-mass planets. Stars hosting exclusively close-in giant planets show higher metallicities and positive -Tc slope. A search for correlations between the -Tc slopes and the ...
Maldonado, J; Villaver, E; Montesinos, B; Mora, A
DiSC: Benchmarking Secure Chip DBMS Nicolas Anciaux, Luc Bouganim, Philippe Pucheral, and Patrick Valduriez
DiSC: Benchmarking Secure Chip DBMS Nicolas Anciaux, Luc Bouganim, Philippe Pucheral, and Patrick irrelevant. The main problem faced by secure chip DBMS designers is to be able to assess various design choices and trade-offs for different applications. Our solution is to use a benchmark for secure chip DBMS
Formation of Spiral Structures in Galactic Discs from Reaction-Diffusion Networks
In this paper, we propose an extension of the Smolin-model of a galactic disc in isolated, flocculent SC-type galaxies. This model supplies the necessary mechanism to suppress spatial inhomogeneities on short distance scales not present in the model proposed by Smolin.
A. Freund
Gathering data on allegations of sexual abuse made against former disc jockey, Jimmy Savile�
This paper will report on a collaboration between Social Work and Informatics academics and Library staff at the University. The focus of the work is to secure a data set on allegations of sexual abuse made against the former disc jockey, Jimmy...
Smith, Mark; Kirkwood, Steve; Llewellyn, Clare
Energetics of star-disc encounters in the non-linear regime
We investigate the response of a circumstellar accretion disc to the fly-by of a perturbing mass on a parabolic orbit. The energy and angular momentum transferred during the encounter are calculated using a reduced three-body method. In almost all close encounters the energy and angular momentum transfer is dominated by disc material becoming unbound from the system, with the contributions from close disc particle -- star encounters being significant. For more distant encounters with some prograde element to the motion the disc material loses energy and angular momentum to the perturber's orbit through a resonance feature. The magnitude of the energy transfer calculated in our simulations is greater than that of the binding energy of material exterior to periastron by a factor of two in the prograde case, and up to a factor of five in the case of the retrograde encounter. The destructive nature of the encounters indicates that a non-linear treatment is essential in all but the most distant encounters.
S. M. Hall; C. J. Clarke; J. E. Pringle
Anisotropic radiation from accretion disc-coronae in active galactic nuclei
In the unification scheme of active galactic nuclei (AGN), Seyfert 1s and Seyfert 2s are intrinsically same, but they are viewed at different angles. However, the Fe K\\alpha emission line luminosity of Seyfert 1s was found in average to be about twice of that of Seyfert 2s at given X-ray continuum luminosity in the previous work (Ricci et al. 2014). We construct an accretion disc-corona model, in which a fraction of energy dissipated in the disc is extracted to heat the corona above the disc. The radiation transfer equation containing Compton scattering processes is an integro-differential equation, which is solved numerically for the corona with a parallel plane geometry. We find that the specific intensity of X-ray radiation from the corona changes little with the viewing angle \\theta when \\theta is small (nearly face-on), and it is sensitive to \\theta if the viewing angle is large (\\theta> 40 degrees). The radiation from the cold disc, mostly in infrared/optical/UV bands, is almost proportional to cos\\thet...
Xu, Ya-Di
Internal Alignments of Red Versus Blue Discs in Dark Matter Halos
Large surveys have shown that red galaxies are preferentially aligned with their halos while blue galaxies have a more isotropic distribution. Since halos generally align with their filaments this introduces a bias in the measurement of the cosmic shear from weak lensing. It is therefore vitally important to understand why this difference arises. We explore the stability of different disc orientations within triaxial halos. We show that, in the absence of gas, the disc orientation is most stable when its spin is along the minor axis of the halo. Instead when gas cools onto a disc it is able to form in almost arbitrary orientation, including off the main planes of the halo (but avoiding an orientation perpendicular to the halo's intermediate axis). Substructure helps gasless galaxies reach alignment with the halo faster, but have less effect on galaxies when gas is cooling onto the disc. Our results provide a novel and natural interpretation for why red, gas poor galaxies are preferentially aligned with their ...
Debattista, Victor P; Roskar, Rok; Quinn, Thomas; Moore, Ben; Cole, David R
Sedimenting discs in a two-dimensional foam I. T. Davies, S. J. Cox
-dimensional foams can be thought of as a monolayer of bubbles squeezed between two glass plates. We choose to probeSedimenting discs in a two-dimensional foam I. T. Davies, S. J. Cox Institute of Mathematics in a dry two-dimensional, monodisperse foam is studied. This, a variation of the classical Stokes
Cox, Simon
Front surface thermal property measurements of air plasma spray coatings
A front-surface measurement for determining the thermal properties of thermal barrier coatings has been applied to air plasma spray coatings. The measurement is used to determine all independent thermal properties of the coating simultaneously. Furthermore, with minimal requirements placed on the sample and zero sample preparation, measurements can be made under previously impossible conditions, such as on serviceable engine parts. Previous application of this technique was limited to relatively thin coatings, where a one-dimensional heat transfer model is applied. In this paper, the influence of heat spreading on the measurement of thicker coatings is investigated with the development of a two-dimensional heat transfer model.
Bennett, Ted; Kakuda, Tyler [University of California, Santa Barbara, California 93106-5070 (United States); Kulkarni, Anand [Siemens Energy, Orlando, Florida 32826-2399 (United States)
Automatic signal processing of front monitor radar for tunneling machines
It is planned to install a front monitoring impulse radar on the surface of the rotating drill of tunneling machines in order to detect obstacles such as casing pipes of vertical borings. The conventional aperture synthesis technique can no more be applied to such cases because the radar image of a pipe dies not constituent a hyperbola as is the case for linear scanning radars. The authors have developed a special purpose signal processing algorithm with the aid of the discrete model fitting method, which can be used for any pattern of scanning. The details of the algorithm are presented together with the results of numerical simulations and test site experiments.
Sato, Toru [Kyoto Univ. (Japan). Dept. of Electronics and Communication] [Kyoto Univ. (Japan). Dept. of Electronics and Communication; Takeda, Kenya [NTT Co. Ltd., Chiba (Japan)] [NTT Co. Ltd., Chiba (Japan); Nagamatsu, Takashi [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)] [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan); Wakayama, Toshio [Mitsubishi Electric Corp., Kamakura, Kanagawa (Japan)] [Mitsubishi Electric Corp., Kamakura, Kanagawa (Japan); Kimura, Iwane [Osaka Inst. of Tech., Hirakata, Osaka (Japan)] [Osaka Inst. of Tech., Hirakata, Osaka (Japan); Shinbo, Tetsuya [Komatsu Co. Ltd., Kanagawa (Japan)] [Komatsu Co. Ltd., Kanagawa (Japan)
BLM Sierra Front Field Office | Open Energy Information
Open Energy Info (EERE)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of InspectorConcentrating SolarElectricEnergyCT BiomassArnprior,Aurantia SACitas JumpCenter JumpSensitiveFront
New RPC front-end electronics for hades
Time-of-flight (TOF) detectors are mainly used for both particle identification and triggering. Resistive Plate Chamber (RPC) detectors are becoming widely used because of their excellent TOF capabilities and reduced cost. The new ESTRELA* RPC wall, which is being installed in the HADES detector at Darmstadt GSI, will contain 1024 RPC modules, covering an active area of around 7 m2. It has excellent TOF and good charge resolutions. Its Front-End electronics is based on a 8-layer Mother-Board providing impedance matched paths for the output signals of each of the eight 4-channel Daughter-Boards to the TDC.
Gil, Alejandro; Cabanelas, P; D�az, J; Garz�n, J A; Gonz�lez-D�az, D; K�nig, W; Lange, J S; Mar�n, J; Montes, N; Skott, P; Traxler, M
Environmentally benign manufacturing of compact disc stampers [Final Phase II report
Optical data storage is currently a $10B/yr. business. With the introduction of the high capacity Digital Versatile Disc (D/D) as well as the continued growth of CD-Audio and CD-ROM worldwide sales of optical data products as a whole are growing at rate of more than 10% per year. In North America, more than 2.5 billion optical discs will be sold in 1998. By 1999, the numbers of optical discs produced for the North American market will grow to almost three billion. The optical disc manufacturing industry is dominated by Asian and European companies (e.g. Sony of Japan and Philips of Netherlands). Prism Corporation has created a process that could significantly improve US competitiveness in the business of optical disc production. The objectives of the Phase II STTR project were to build and test an ion machining system (IMS) for stamper fabrication, prove overall manufacturing system feasibility by fabrication stampers and replicas, and evaluate alternative materials and alternative process parameters to optimize the process. During tie period of the Phase II project Prism Corporation was able to meet these objectives. In the course of doing so, adjustments had been made to better the project and in turn the final product. An ion machining system was designed and built that produced stampers ready for the molding process. Also, many control steps in the manufacturing process were studied to improve the current process and make it even more compatible with the industry standards, fitting seamlessly into current manufacturing lines.
The dynamics of combustion fronts in porous media
In this report, a method for solving this problem by treating the reaction region as a place of discontinuities in the appropriate variables, which include, for example, fluxes of heat and mass was proposed. Using a rigorous perturbation approach, similar to that used in the propagation of flames and smoldering combustion, appropriate jump conditions that relate the change in these variables across the front was derived. These conditions account for the kinetics of the reaction between the oxidant and the fuel, the changes in the morphology of the pore space and the heat and mass transfer in the reaction zone. The modeling of the problem reduces to the modeling of the dynamics of a combustion front, on the regions of either side of which transport of momentum (fluids), heat and mass, but not chemical reactions, must be considered. Properties of the two regions are coupled using the derived jump conditions. This methodology allows one to explicitly incorporate permeability heterogeneity effects in the process description, without the undue complexity of the coupled chemical reactions.
Akkutlu, I. Yucel; Yortsos, Yannis C.
The response of self-graviting protostellar discs to slow reduction in cooling timescale: the fragmentation boundary revisited
A number of previous studies of the fragmentation of self-gravitating protostellar discs have modeled radiative cooling with a cooling timescale (t_{cool}) parameterised as a simple multiple (beta_{cool}) of the local dynamical timescale. Such studies have delineated the `fragmentation boundary' in terms of a critical value of beta_{cool} (beta_{crit}), where the disc fragments if beta_{cool} < beta_{crit}. Such an approach however begs the question of how in reality a disc could ever be assembled with beta_{cool} < beta_{crit}. Here we adopt the more realistic approach of gradually reducing beta_{cool}, as might correspond to changes in thermal regime due to secular changes in the disc density profile. We find that when beta_{cool} is gradually reduced (on a timescale longer than t_{cool}), the disc is stabilised against fragmentation, compared with models in which beta_{cool} is reduced rapidly. We therefore conclude that a disc's ability to remain in a self-regulated, self-gravitating state (without fragmentation) is partly dependent on its thermal history, as well as its current cooling rate. Nevertheless, a slow reduction in t_{cool} appears only to lower the fragmentation boundary by about a factor two in t_{cool} and thus only permits maximum alpha values (parameterising the efficiency of angular momentum transfer in the disc) that are about a factor two higher than determined hitherto. Our results therefore do not undermine the notion of a fundamental upper limit to the heating rate that can be delivered by gravitational instabilities before the disc is subject to fragmentation. An important implication of this work, therefore, is that self-gravitating discs can enter into the regime of fragmentation via secular evolution and it is not necessary to invoke rapid (impulsive) events to trigger fragmentation.
C. Clarke; E. Harper-Clark; G. Lodato
Pion light-front wave function, parton distribution and the electromagnetic form factor
We derive a light-front wave function of the pion, which reproduces its valence parton distribution and a electromagnetic form factor consistent with data.
Thomas Gutsche; Valery E. Lyubovitskij; Ivan Schmidt; Alfredo Vega
E-Print Network 3.0 - automobile front panel Sample Search Results
Search Powered by Explorit Topic List Advanced Search Sample search results for: automobile front panel Page: << < 1 2 3 4 5 > >> 1 FUTURES OF AUTOMOBILE INDUSTRY AND...
E-Print Network 3.0 - atlas front-end links Sample Search Results
on behalf of the ATLAS collaboration Summary: and TILES calorimeters: All in the cavern, Barrel LARG cryostat is cold, Barrel Front end electronics all... . Perrodo Detector...
E-Print Network 3.0 - atlas pixel front-end Sample Search Results
Method and system for assigning a confidence metric for automated determination of optic disc location
A method for assigning a confidence metric for automated determination of optic disc location that includes analyzing a retinal image and determining at least two sets of coordinates locating an optic disc in the retinal image. The sets of coordinates can be determined using first and second image analysis techniques that are different from one another. An accuracy parameter can be calculated and compared to a primary risk cut-off value. A high confidence level can be assigned to the retinal image if the accuracy parameter is less than the primary risk cut-off value and a low confidence level can be assigned to the retinal image if the accuracy parameter is greater than the primary risk cut-off value. The primary risk cut-off value being selected to represent an acceptable risk of misdiagnosis of a disease having retinal manifestations by the automated technique.
Karnowski, Thomas P. (Knoxville, TN); Tobin, Jr., Kenneth W. (Harriman, TN); Muthusamy Govindasamy, Vijaya Priya (Knoxville, TN); Chaum, Edward (Memphis, TN)
Snow-lines as probes of turbulent diffusion in protoplanetary discs
Sharp chemical discontinuities can occur in protoplanetary discs, particularly at `snow-lines' where a gas-phase species freezes out to form ice grains. Such sharp discontinuities will diffuse out due to the turbulence suspected to drive angular momentum transport in accretion discs. We demonstrate that the concentration gradient - in the vicinity of the snow-line - of a species present outside a snow-line but destroyed inside is strongly sensitive to the level of turbulent diffusion (provided the chemical and transport time-scales are decoupled) and provides a direct measurement of the radial `Schmidt number' (the ratio of the angular momentum transport to radial turbulent diffusion). Taking as an example the tracer species N$_2$H$^+$, which is expected to be destroyed inside the CO snow-line (as recently observed in TW Hya) we show that ALMA observations possess significant angular resolution to constrain the Schmidt number. Since different turbulent driving mechanisms predict different Schmidt numbers, a d...
Owen, James E
The ejection of T Tauri stars from molecular clouds and the fate of circumstellar discs
We investigate the evolution of circumstellar discs around T Tauri stars that are ejected from small stellar clusters within molecular clouds. In particular, we study how the interaction that leads to ejection may hasten the transition between Classical and Weak-lined T Tauri status. In our models, ejections of T Tauri stars at velocities of 3-10 km/s truncate the accretion disc at radii between 1 and 10 a.u., reducing the viscous evolution time of the disc so that accretion rapidly ceases. The observational appearance of the resulting systems is then dependent on the presence or absence of a stellar magnetic field. For non-magnetic stars we find that a near-infra red excess should persist due to reprocessing of stellar radiation, but that this is greatly diminished for magnetic T Tauri stars by the presence of a magnetosphere extending to corotation. In either case, there is a period when ejected stars should appear as non-accreting systems with detectable circumstellar material at wavelengths of 5 microns and beyond. We discuss the implications of these results for models in which ejected stars contribute to the halo of pre-main-sequence objects discovered from ROSAT observations of star forming regions and the All-Sky Survey.
Variable Emission from a Gaseous Disc around a Metal-Polluted White Dwarf
We present the discovery of strongly variable emission lines from a gaseous disc around the DA white dwarf SDSS J1617+1620, a star previously found to have an infrared excess indicative of a dusty debris disc formed by the tidal disruption of a rocky planetary body. Time-series spectroscopy obtained during the period 2006-2014 has shown the appearance of strong double-peaked Ca II emission lines in 2008. The lines were weak, at best, during earlier observations, and monotonically faded through the remainder of our monitoring. Our observations represent unambiguous evidence for short-term variability in the debris environment of evolved planetary systems. Possible explanations for this extraordinary variability include the impact onto the dusty disc of either a single small rocky planetesimal, or of material from a highly eccentric debris tail. The increase in flux from the emission lines is sufficient that similar events could be detected in the broadband photometry of ongoing and future large-area time domai...
Wilson, David J; Koester, Detlev; Raddi, Roberto; Breedt, Elm�; Southworth, John; Parsons, Steven G
Wave Front Interaction Model of Stabilized Propagating Wave Segments Vladimir S. Zykov1
Wave Front Interaction Model of Stabilized Propagating Wave Segments Vladimir S. Zykov1 and Kenneth; published 14 February 2005) A wave front interaction model is developed to describe the relationship between excitability and the size and shape of stabilized wave segments in a broad class of weakly excitable media
Air-sea interaction at an oceanic front: Implications for frontogenesis and primary production
Air-sea interaction at an oceanic front: Implications for frontogenesis and primary production Dake a significant air-sea interaction at the shelf- break front in the East China Sea. An idealized ocean was identified in the model and its consequences were evaluated. We found that air-sea interaction, when combined
Chen, .Dake
A Review of Cold Fronts with Prefrontal Troughs and Wind Shifts DAVID M. SCHULTZ
A Review of Cold Fronts with Prefrontal Troughs and Wind Shifts DAVID M. SCHULTZ Cooperative with a pressure trough and a distinct wind shift at the surface. Many cold fronts, however, do not conform to this model--time series at a single surface station may possess a pressure trough and wind shift in the warm
Schultz, David
The Interruption of Alpine Foehn by a Cold Front. Part I: Observations
propagation speed wf 1 m/s Inclination of the frontal surface is wf /uf 1/7.5 8� Freitag (1990 in valleys Interaction with local winds (e.g., foehn) foehn cold front Cold front in complex terrain ? ? #12 in Inn and Wipp Valley Temperature slope profile Doppler wind lidar in Wipp Valley #12;6 of 13 Case study
Gohm, Alexander
CISC 327 -Fall 2014 ! Course Project Assignment #1 -Front End Requirements!
represent those requirements as a set of requirements tests. The basic idea is to analyze the requirements, and create a test case for each piece. We will study this more in class.! !Create and organize a complete set of requirements tests for the Front End of Quinterac, to test for every required behaviour (of the Front End only
Cordy, James R.
Validity of wave-front reconstruction and propagation of ultrabroadband pulses measured
laser pulses from a hollow fiber can be propagated correctly by a single polychromatic wave. © 2005 Optical Society of America OCIS codes: 320.0320, 140.7090. Many experiments in laser physics-front characterization. Beam wave front, spatial irradiance distribution, and coherence properties are needed
Keller, Ursula
Fast 3D Brain Segmentation Using Dual-Front Active Contours with Optional User-Interaction
Fast 3D Brain Segmentation Using Dual-Front Active Contours with Optional User-Interaction Hua Li1 attributes of 3D brain segmentation algorithms in- clude robustness, accuracy, computational efficiency result. We propose a novel 3D brain cortex segmentation procedure utilizing dual- front active contours
Cohen, Laurent
Lattice Boltzmann BGK simulation of non-linear sound waves: The development of a shock front
Lattice Boltzmann BGK simulation of non-linear sound waves: The development of a shock front J. M Boltzmannsimulationsofthe development of a shock front are performed when a sound wave is emitted from a high amplitude.1088/0305-4470/33/21/305 #12;Lattice Boltzmann BGK simulation of non-linear sound waves 2 1. Introduction The lattice
Traveling Fronts of Copper Deposition Stephanie Thouvenel-Romans, Konstantin Agladze, and Oliver Steinbock*
Traveling Fronts of Copper Deposition Stephanie Thouvenel-Romans, Konstantin Agladze, and Oliver for propagating fronts that mediate the electroless deposition of copper on passivated steel. Under ap- propriate is essentially independent from the copper(II) concentration in the electrolyte, which indicates
Steinbock, Oliver
IMA Journal of Applied Mathematics (2002) 67, 419439 Modelling thermal front dynamics in microwave heating
an electric field is applied to materials with high resistivity, the dipole moments of the molecules alignIMA Journal of Applied Mathematics (2002) 67, 419439 Modelling thermal front dynamics in microwave July 2000; revised on 6 December 2001] The formation and propagation of thermal fronts in a cylindrical
Xin, Jack
Silicon Solar Cells with Front Hetero-contact and Aluminum Alloy Back Junction (Poster)
The objectives of this report are: (1) to apply industrial back Al process in efficient n-wafer cells with a-Si:H front surface passivation; and (2) to evaluate the surface recombination velocity (SRV) of the a-Si:H passivated front surface with different surface preparation procedures.
Yuan, H.-C.; Page, M. R.; Iwaniczko, E.; Xu, Y.; Roybal, L.; Wang, Q.; Branz, H. M.; Meier, D. L.
Asymmetry of Columbia River tidal plume fronts David A. Jay a,
or northern side and mark a transition from supercritical to subcritical flow for up to 12 h after high water plume water mass. This vorticitycontrols the transition of the tidal plume front to a subcritical state plume may overlie newly upwelled waters, these fronts can mix nutrients into the plume. Symmetry would
Hickey, Barbara
Mineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW China
, People's Republic of China c Northwest Institute of Uranium Geology, China National Nuclear CorporationMineral paragenesis and textures associated with sandstone-hosted roll-front uranium deposits, NW, Wuyiyi and Shihongtan sandstone-hosted roll-front uranium deposits, northwest China. The mineralization
Fayek, Mostafa
Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern China
Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern Available online 25 January 2005 Abstract We show evidence that the primary uranium minerals, uraninite-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically
SiGe receiver front ends and flip-chip integrated wideband antennas for millimeter-wave passive imaging
SiGe wideband 77-GHz and 94-GHz front end receivers with integrated antennas for passive imaging have been designed and characterized. These front end systems exhibit wideband performance with the highest gain and lowest ...
Powell, Johnna, 1980-
Front-end electronics and trigger systems - status and challenges
The past quarter century has brought about a revolution in front-end electronics for large-scale detector systems. Custom integrated circuits specifically tailored to the requirements of large detector systems have provided unprecedented performance and enabled systems that once were deemed impossible. The evolution of integrated circuit readouts in strip detectors is summarized, the present status described, and challenges posed by the sLHC and ILC are discussed. Performance requirements increase, but key considerations remain as in the past: power dissipation, material, and services. Smaller CMOS feature sizes will not provide the required electronic noise at lower power, but will improve digital power efficiency. Significant improvements appear to be practical in more efficient power distribution. Enhanced digital electronics have provided powerful trigger processors that greatly improve the trigger efficiency. In data readout systems they also improve data throughput, while reducing power requirements. Concurrently with new developments in high energy physics, detector systems for cosmology and astrophysics have made great strides. As an example, a large-scale readout for superconducting bolometer arrays is described.
Spieler, Helmuth G; Spieler, Helmuth G
Inhibition of slug front corrosion in multiphase flow conditions
Corrosion at the slug front at the bottom of a pipeline is identified as one of the worst cases of corrosion occurring in the pipeline which carries unprocessed multiphase production with a high level of CO{sub 2} gas. One objective of the study in recommending a subsea completion to shore was to determine if commercial corrosion inhibitors can control this type of corrosion using carbon steel pipeline. Thus, inhibitors which showed excellent performance in the lab using the Rotating Cylinder Electrode system (RCE) were further evaluated to confirm their performance in a flow loop simulating the test conditions predicted from the flow modeling for the proposed pipeline. The performance profile of two commercial inhibitors were determined in a 4 in. flow loop at 7O C, 100 psig CO{sub 2} partial pressure in corrosive brines with or without ethylene glycol and/or light hydrocarbon. Results showed that the carbon steel pipeline could be adequately protected at low temperature using a commercial corrosion inhibitor to meet the designed life of the pipeline. Ethylene glycol, which is used in the pipeline to prevent hydrate formation, reduces the corrosivity of the brine and gives no effect on inhibitor performance under the slug flow conditions. A good agreement in inhibitor performance was observed between the flow loop and the RCE testing. The uninhibited corrosion rate of the test brine in this study is in good agreement with the predicted value using deWaard and Williams correlation for CO{sub 2} corrosion.
Chen, H.J. [Chevron Petroleum Technology Co., La Habra, CA (United States); Jepson, W.P. [Ohio Univ., Athens, OH (United States)
Characterization of the coherent noise, electromagnetic compatibility and electromagnetic interference of the ATLAS EM calorimeter Front End Board
Characterization of the coherent noise, electromagnetic compatibility and electromagnetic interference of the ATLAS EM calorimeter Front End Board
Chase, B E; Lanni, F; Makowiecki, D S; Radeka, V; Rescia, S; Takai, H; B�n, J; Parsons, J; Sippach, W
Low Power Front-End Electronics for the BESS-Polar Time-of-Flight Counter and Aerogel Cherenkov Counter
Low Power Front-End Electronics for the BESS-Polar Time-of-Flight Counter and Aerogel Cherenkov Counter
Sasaki, M
Light-Front Quantization Approach to the Gauge-Gravity Correspondence and Hadron Spectroscopy
We find a correspondence between semiclassical QCD quantized on the light-front and a dual gravity model in anti--de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence--light-front holography--leads to a light-front Hamiltonian and relativistic bound-state wave equations that are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within hadrons at equal light-front time. The eigenvalues of the resulting light-front Schroedinger and Dirac equations are consistent with the observed light meson and baryon spectrum, and the eigenmodes provide the light-front wavefunctions, the probability amplitudes describing the dynamics of the hadronic constituents. The light-front equations of motion, which are dual to an effective classical gravity theory, possess remarkable algebraic and integrability properties which are dictated by the underlying conformal properties of the theory. We extend the algebraic construction to include a confining potential while preserving the integrability of the mesonic and baryonic bound-state equations.
Teramond, Guy F. de [Universidad de Costa Rica, San Jose (Costa Rica); Brodsky, Stanley J. [SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309 (United States)
Light-Front Holography, AdS/QCD, and Hadronic Phenomena
AdS/QCD, the correspondence between theories in a modified five-dimensional anti-de Sitter space and confining field theories in physical space-time, provides a remarkable semiclassical model for hadron physics. Light-front holography allows hadronic amplitudes in the AdS fifth dimension to be mapped to frame-independent light-front wavefunctions of hadrons in physical space-time, thus providing a relativistic description of hadrons at the amplitude level. We identify the AdS coordinate z with an invariant light-front coordinate {zeta} which separates the dynamics of quark and gluon binding from the kinematics of constituent spin and internal orbital angular momentum. The result is a single-variable light-front Schroedinger equation with a confining potential which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The mapping of electromagnetic and gravitational form factors in AdS space to their corresponding expressions in light-front theory confirms this correspondence. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. The distinction between static structure functions, such as the probability distributions computed from the square of the light-front wavefunctions, versus dynamical structure functions which include the effects of rescattering, is emphasized. A new method for computing the hadronization of quark and gluon jets at the amplitude level, an event amplitude generator, is outlined.
HIGH-EFFICIENCY BACK-JUNCTION SILICON SOLAR CELL WITH AN IN-LINE EVAPORATED ALUMINUM FRONT GRID M-diffused back-junction emitter. The aluminum front side grid is evaporated in an industrial-type in-thick silicon shadow masks for the in-line evaporation of the aluminum front grid. The masks are fabricated
Travelling fronts of the CO oxidation on Pd(111) with coverage-dependent diffusion
In this work, we study a surface reaction on Pd(111) crystals under ultra-high-vacuum conditions that can be modeled by two coupled reaction-diffusion equations. In the bistable regime, the reaction exhibits travelling fronts that can be observed experimentally using photo electron emission microscopy. The spatial profile of the fronts reveals a coverage-dependent diffusivity for one of the species. We propose a method to solve the nonlinear eigenvalue problem and compute the direction and the speed of the fronts based on a geometrical construction in phase-space. This method successfully captures the dependence of the speed on control parameters and diffusivities.
Cisternas, Jaime, E-mail: email@example.com [Facultad de Ingenier�a y Ciencias Aplicadas, Universidad de los Andes, Monse�or Alvaro del Portillo 12455, Las Condes, Santiago (Chile); Karpitschka, Stefan [Physics of Fluids, University of Twente, Drienerlolaan 5, 7522 NB Enschede (Netherlands); Wehner, Stefan [Institut f�r Integrierte Naturwissenschaften - Physik, Universit�t Koblenz-Landau, 56070 Koblenz (Germany)
Equatorial scattering and the structure of the broad-line region in Seyfert nuclei: evidence for a rotating disc
We present detailed scattering models confirming that distinctive variations in polarization across the broad Halpha line, which are observed in a significant fraction of Seyfert 1 galaxies, can be understood in terms of a rotating line-emitting disc surrounded by a co-planar scattering region (the equatorial scattering region). The predicted polarization properties are: averaged over wavelength, the position angle of polarization is aligned with the projected disc rotation axis and hence also with the radio source axis; (ii) the polarization PA rotates across the line profile, reaching equal but opposite (relative to the continuum PA) rotations in the blue and red wings; (iii) the degree of polarization peaks in the line wings and passes through a minimum in the line core. We identify 11 objects which exhibit these features to different degrees. In order to reproduce the large amplitude PA rotations observed in some cases, the scattering region must closely surround the emission disc and the latter must itself be a relatively narrow annulus -- presumably the Halpha-emitting zone of a larger accretion disc. Asymmetries in the polarization spectra may be attributable to several possible causes, including bulk radial infall in the equatorial scattering region, or contamination by polar scattered light. The broad Halpha lines do not, in general, exhibit double-peaked profiles, suggesting that a second Halpha-emitting component of the broad-line region is present, in addition to the disc.
J. E. Smith; A. Robinson; S. Young; D. J. Axon; Elizabeth A. Corbett
Disc evolution and the relationship between $L_{\\rm acc}$ and $L_\\ast$ in T Tauri stars
We investigate the evolution of accretion luminosity $L_{\\rm acc}$ and stellar luminosity ${L_\\ast}$ in pre-mainsequence stars. We make the assumption that when the star appears as a Class II object, the major phase of accretion is long past, and the accretion disc has entered its asymptotic phase. We use an approximate stellar evolution scheme for accreting pre-mainsequence stars based on Hartmann, Cassen & Kenyon, 1997. We show that the observed range of values $k = L_{\\rm acc}/L_\\ast$ between 0.01 and 1 can be reproduced if the values of the disc mass fraction $M_{\\rm disc}/M_*$ at the start of the T Tauri phase lie in the range 0.01 -- 0.2, independent of stellar mass. We also show that the observed upper bound of $L_{\\rm acc} \\sim L_\\ast$ is a generic feature of such disc accretion. We conclude that as long as the data uniformly fills the region between this upper bound and observational detection thresholds, then the degeneracies between age, mass and accretion history severely limit the use of this data for constraining possible scalings between disc properties and stellar mass.
I. Tilling; C. J. Clarke; J. E. Pringle; C. A. Tout
26-percent efficient point-junction concentrator solar cells with a front metal grid
This paper reports on silicon concentrator cells with point diffusions and metal contacts on both the front and back sides. The design minimizes reflection losses by forming an inverted pyramid topography on the front surface and by shaping the metal grid lines in the form of a triangular ridge. A short-circuit current density of 39.6 mA/cm{sup 2} has been achieved even though the front grid covers 16 percent of the cell's active area of 1.56 cm{sup 2}. This, together with an open-circuit voltage of 700 mV, has led to an efficiency of 22 percent at one sun, AM1.5 global spectrum. Under direct-spectrum, 8.8-W/cm{sup 2}, concentrated light, the efficiency is 26 percent. This is the highest ever reported for a silicon cell having a front metal grid.
Cuevas, A.; Sinton, R.A.; Midkiff, N.E.; Swanson, R.M. (Stanford Univ., CA (USA). Dept. of Electrical Engineering)
Detection technique and front-end RF tunable filter for cognitive radio systems
dual-mode WiMAX/WLAN direct- conversion receiver,� in Proc.Hamilton, �Aspects of direct conversion receiver design,� inand M. Ismail, �A direct conversion WiMAX RF receiver front-
Park, Sanghoon
Dusty gust fronts and their contributions to long-lived convection in West Africa/
To model and predict the behavior of West African storms and mesoscale convective systems (MCSs), we must understand the life cycle of gust fronts, which invariably accompany thunderstorms and often initiate them. In this ...
McGraw-Herdeg, Michael (Michael P.)
A survey of front end modularity as an automotive architecture and its ability to deliver value
The partitioning of a system can and will dictate the creative space for a designer or engineer. This thesis will analyze how using a new automotive architecture known as a Front End Module (FEM) can affect a limited ...
Mah�, Vincent R. (Vincent Robert)
Electronic-nose for detecting environmental pollutants: signal processing and analog front-end design
noise floor analog front-end (AFE) fol- lowed by a signal processing stage. In this paper, we present the output of eight conductometric sensors and eight ampero- metric electrochemical sensors and achieves 91 d
E-Print Network 3.0 - augmented hadronic light-front Sample Search...
Jagiellonski Collection: Physics 5 Vol. 32 (2001) ACTA PHYSICA POLONICA B No 12 QCD PHENOMENOLOGY AND LIGHT-FRONT Summary: of a hadrons in terms of a set of frame-independent...
E-Print Network 3.0 - aps beamline front Sample Search Results
Page 1 of 11 Policy& Procedure : 3.1.37 Summary: The beamline front end provides the UHV transition from the APS storage ring through the ratchet wall... to the portions of the...
Autonomous detection and anticipation of jam fronts from messages propagated by inter-vehicle communication
In this paper, a minimalist, completely distributed freeway traffic information system is introduced. It involves an autonomous, vehicle-based jam front detection, the information transmission via inter-vehicle communication, and the forecast of the spatial position of jam fronts by reconstructing the spatiotemporal traffic situation based on the transmitted information. The whole system is simulated with an integrated traffic simulator, that is based on a realistic microscopic traffic model for longitudinal movements and lane changes. The function of its communication module has been explicitly validated by comparing the simulation results with analytical calculations. By means of simulations, we show that the algorithms for a congestion-front recognition, message transmission, and processing predict reliably the existence and position of jam fronts for vehicle equipment rates as low as 3%. A reliable mode of operation already for small market penetrations is crucial for the successful introduction of inter-...
Sch"onhof, M; Kesting, A; Helbing, D; Sch\\"onhof, Martin; Treiber, Martin; Kesting, Arne; Helbing, Dirk
Non-Adiabatic Effects on Combustion Front Propagation in Porous Media: Multiplicity of Steady States
The sustained propagation of combustion fronts in porous media is a necessary condition for the success of an in situ combustion project for oil recovery. Compared to other recovery methods, in situ combustion involves the added complexity of exothermic reactions and temperature-dependent chemical kinetics. In the presence of heat losses, the possibility of ignition and extinction (quenching) exists. In this report, we address the properties of combustion fronts propagating at a constant velocity in the presence of heat losses.
Akkutlu, I. Yucel; Yortsos, Yanis C.
The Communist revolution in Republican China: the conceptual development of the second united front.
THE COMMUNIS( RE'JOLUT ION IN REPUBL ICAN CHINA: THE CONCEPTUAL DEVELOPMENT OF THE SECOND UNITED FRONT A Thesis by BRIAN LANNES HOPE Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement... for the degree oi MASTER OF ARTS December, 1974 Major Subject: Political Science THE COMMUNIST REVOLUTION IN REPUBLICAN CHINA: THE CONCEPTUAL DEVELOPMENT OF THE SECOND UNITED FRONT A Thesis by BRIAN LANNES HOPE Approved as to style and content by: +~9...
Hope, Brian Lannes
Light-Front Quantization Approach to the Gauge Gravity Correspondence and Hadron Spectroscopy
We find a correspondence between semiclassical QCD quantized on the light-front and a dual gravity model in anti-de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence - light-front holography - leads to a light-front Hamiltonian and relativistic bound-state wave equations that are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within hadrons at equal lightfront time. The eigenvalues of the resulting light-front Schrodinger and Dirac equations are consistent with the observed light meson and baryon spectrum, and the eigenmodes provide the light-front wavefunctions, the probability amplitudes describing the dynamics of the hadronic constituents. The light-front equations of motion, which are dual to an effective classical gravity theory, possess remarkable algebraic and integrability properties which are dictated by the underlying conformal properties of the theory. We extend the algebraic construction to include a confining potential while preserving the integrability of the mesonic and baryonic bound-state equations.
de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC
Migration of Earth-size planets in 3D radiative discs
In this paper, we address the migration of small mass planets in 3D radiative disks. Indeed, migration of small planets is known to be too fast inwards in locally isothermal conditions. However, thermal effects could reverse its direction, potentially saving planets in the inner, optically thick parts of the protoplanetary disc. This effect has been seen for masses larger than 5 Earth masses, but the minimum mass for this to happen has never been probed numerically, although it is of crucial importance for planet formation scenarios. We have extended the hydro-dynamical code FARGO to 3D, with thermal diffusion. With this code, we perform simulations of embedded planets down to 2 Earth masses. For a set of discs parameters for which outward migration has been shown in the range of $[5, 35]$ Earth masses, we find that the transition to inward migration occurs for masses in the range $[3, 5]$ Earth masses. The transition appears to be due to an unexpected phenomenon: the formation of an asymmetric cold and dense...
Lega, E; Bitsch, B; Morbidelli, A
The structure and kinematics of the the Galaxy thin gaseous disc outside the solar orbit
The rotation curve of the Galaxy is generally thought to be flat. However, using radial velocities from interstellar molecular clouds, which is common in rotation curve determination, seems to be incorrect and may lead to incorrectly inferring that the rotation curve is flat indeed. Tests basing on photometric and spectral observations of bright stars may be misleading. The rotation tracers (OB stars) are affected by motions around local gravity centers and pulsation effects seen in such early type objects. To get rid of the latter a lot of observing work must be involved. We introduce a method of studying the kinematics of the thin disc of our Galaxy outside the solar orbit in a way that avoids these problems. We propose a test based on observations of interstellar CaII H and K lines that determines both radial velocities and distances. We implemented the test using stellar spectra of thin disc stars at galactic longitudes of 135{\\degr} and 180{\\degr}. Using this method, we constructed the rotation curve of ...
Galazutdinov, G A; Musaev, F A; Bondar, A; Krelowski, J
applied modal analysis: Topics by E-print Network
instability. Introduction Disc brake noise continues to be object of investigation for automotive-mail: firstname.lastname@example.com Abstract In this paper, an experimental...
AdS/QCD and Applications of Light-Front Holography
Light-Front Holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space and frame-independent light-front wavefunctions of hadrons in 3 + 1 physical space-time, thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD, a useful framework which describes the correspondence between theories in a modified AdS5 background and confining field theories in physical space-time. To a first semiclassical approximation, where quantum loops and quark masses are not included, this approach leads to a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time. The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role. We give an overview of the light-front holographic approach to strongly coupled QCD. In particular, we study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The results for the TFFs for the {eta} and {eta}' mesons are also presented. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.
Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Cao, Fu-Guang; /Massey U.; de Teramond, Guy F.; /Costa Rica U.
Localized structures and front propagation in the Lengyel-Epstein model
Pattern selection, localized structure formation, and front propagation are analyzed within the framework of a model for the chlorine dioxide--iodine--malonic acid reaction that represents a key to understanding recently obtained Turing structures. This model is distinguished from previously studied, simple reaction-diffusion models by producing a strongly subcritical transition to stripes. The wave number for the modes of maximum linear gain is calculated and compared with the dominant wave number for the finally selected, stationary structures grown from the homogeneous steady state or developed behind a traveling front. The speed of propagation for a front between the homogeneous steady state and a one-dimensional (1D) Turing structure is obtained. This velocity shows a characteristic change in behavior at the crossover between the subcritical and supercritical regimes for the Turing bifurcation. In the subcritical regime there is an interval where the front velocity vanishes as a result of a pinning of the front to the underlying structure. In 2D, two different nucleation mechanisms for hexagonal structures are illustrated on the Lengyel-Epstein and the Brusselator model. Finally, the observation of 1D and 2D spirals with Turing-induced cores is reported.
Jensen, O.; Pannbacker, V.O.; Mosekilde, E.; Dewel, G.; Borckmans, P. (Physics Department, Technical University of Denmark, 2800 Lyngby (Denmark) Service de Chimie-Physique, Code Postal 231 Universite Libre de Bruxelles, 1050 Brussels (Belgium))
Apparatus for characterizing the temporo-spatial properties of a dynamic fluid front and method thereof
Methods and apparatus are described for characterizing the temporal-spatial properties of a dynamic fluid front within a mold space while the mold space is being filled with fluid. A method includes providing a mold defining a mold space and having one or more openings into the mold space; heating a plurality of temperature sensors that extend into the mold space; injecting a fluid into th emold space through the openings, the fluid experiencing a dynamic fluid front while filling the mold space with a fluid; and characterizing temporal-spatial properties of the dynamic fluid front by monitoring a termperature of each of the plurality of heated temperature sensors while the mold space is being filled with the fluid. An apparatus includes a mold defining a mold space; one or more openings for introducing a fluid into th emold space and filling the mold space with the fluid, the fluid experiencing a dynamic fluid front while filling the mold space; a plurality of heated temperature sensors extending into the mold space; and a computer coupled to the plurality of heated temperature sensors for characterizing the temporal-spatial properties of the dynamic fluid front.
Battiste, Richard L
Methods and apparatus are described for characterizing the temporal-spatial properties of a dynamic fluid front within a mold space while the mold space is being filled with fluid. A method includes providing a mold defining a mold space and having one or more openings into the mold space; heating a plurality of temperature sensors that extend into the mold space; injecting a fluid into the mold space through the openings, the fluid experiencing a dynamic fluid front while filling the mold space with the fluid; and characterizing temporal-spatial properties of the dynamic fluid front by monitoring a temperature of each of the plurality of heated temperature sensors while the mold space is being filled with the fluid. An apparatus includes a mold defining a mold space; one or more openings for introducing a fluid into the mold space and filling the mold space with the fluid, the fluid experiencing a dynamic fluid front while filling the mold space; a plurality of heated temperature sensors extending into the mold space; and a computer coupled to the plurality of heated temperature sensors for characterizing the temporal-spatial properties of the dynamic fluid front.
Battiste, Richard L. (Oak Ridge, TN)
Gauge/Gravity Duality and Strongly Coupled Light-Front Dynamics
We find a correspondence between semiclassical gauge theories quantized on the light-front and a dual gravity model in anti-de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence - light-front holography - leads to a light-front Hamiltonian and relativistic bound-state wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. Light-front holography also allows a precise mapping of transition amplitudes from AdS to physical space-time. In contrast with the usual AdS/QCD framework, the internal structure of hadrons is explicitly introduced in the gauge/gravity correspondence and the angular momentum of the constituents plays a key role. We also discuss how to introduce higher Fock-states in the correspondence as well as their relevance for describing the detailed structure of space and time-like form factors.
de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins
Thickness measurement system for transparent plates using dual digital versatile disc (DVD) pickups
A low-cost high-precision thickness measurement system for transparent plates that uses dual digital versatile disc (DVD) pickups is proposed. The two DVD pickups are used as the transmitter and the receiver in the measurement system, respectively. One of the DVD pickups emits a laser to the other DVD pickup (receiver) and projects on the photodiode integrated circuit of the receiver. The transparent plate is placed in the optical path to change the focused point that will affect the focusing error signal (FES) of the receiver. Using the FES, a mathematical model for thickness measurement based on the geometric optical method is developed. The experimental results show that the accuracy is 1.5 {mu}m, and the uncertainty is estimated to be {+-}1.37 {mu}m for the measured thickness of 150{mu}m.
Liu, Chien-Hung; Yeh, Shien-Chang; Huang, Hsueh-Liang
Towards a fully consistent Milky Way disc model - III. Constraining the initial mass function
We use our vertical Milky Way disc model together with Galaxia to create mock observations of stellar samples in the solar neighbourhood. We compare these to the corresponding volume complete observational samples of dereddened and binary accounted data from Hipparcos and the Catalogue of Nearby Stars. Sampling the likelihood in the parameter space we determine a new fiducial IMF considering constraints from dwarf and giant stars. The resulting IMF observationally backed in the range from 0.5 to 10 Msun is a two slope broken power law with -1.49 +- 0.08 for the low mass slope, a break at 1.39 +- 0.05 Msun and a high mass slope of -3.02 +- 0.06. The Besancon group also converging to a similar IMF even though their observational sample being quite different to ours shows that the forward modelling technique is a powerful diagnostic to test theoretical concepts like the local field star IMF.
Rybizki, Jan
Semi-flexible gas-insulated transmission line using sandwiched discs for intermittent flexing joints
A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by the use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements are formed by sandwiching together, by fusing, a pair of thin hollow discs which are fixedly secured to both the main conductor sections and the conductor hub section. 4 figs.
Kommineni, P.R.
Self-similar Evolution of Self-Gravitating Viscous Accretion Discs
A new one-dimensional, dynamical model is proposed for geometrically thin, self-gravitating viscous accretion discs. The vertically integrated equations are simplified using the slow accretion limit and the monopole approximation with a time-dependent central point mass to account for self-gravity and accretion. It is shown that the system of partial differential equations can be reduced to a single non-linear advection diffusion equation which describes the time evolution of angular velocity. In order to solve the equation three different turbulent viscosity prescriptions are considered. It is shown that for these parametrizations the differential equation allows for similarity transformations depending only on a single non-dimensional parameter. A detailed analysis of the similarity solutions reveals that this parameter is the initial power law exponent of the angular velocity distribution at large radii. The radial dependence of the self-similar solutions is in most cases given by broken power laws. At sma...
Illenseer, Tobias F
Light-front representation of chiral dynamics in peripheral transverse densities
The nucleon's electromagnetic form factors are expressed in terms of the transverse densities of charge and magnetization at fixed light-front time. At peripheral transverse distances $b = O(M_\\pi^{-1})$ the densities are governed by chiral dynamics and can be calculated model-independently using chiral effective field theory (EFT). We represent the leading-order chiral EFT results for the peripheral transverse densities as overlap integrals of chiral light-front wave functions, describing the transition of the initial nucleon to soft pion-nucleon intermediate states and back. The new representation (a) explains the parametric order of the peripheral transverse densities; (b) establishes an inequality between the spin-independent and -dependent densities; (c) exposes the role of pion orbital angular momentum in chiral dynamics; (d) reveals a large left-right asymmetry of the current in a transversely polarized nucleon and suggests a simple interpretation. The light-front representation enables a first-quantiz...
Granados, C
Measures of the Environmental Footprint of the Front End of the Nuclear Fuel Cycle
Previous estimates of environmental impacts associated with the front end of the nuclear fuel cycle have focused primarily on energy consumption and CO2 emissions. Results have varied widely. Section 2 of this report provides a summary of historical estimates. This study revises existing empirical correlations and their underlying assumptions to fit to a more complete set of existing data. This study also addresses land transformation, water withdrawals, and occupational and public health impacts associated with the processes of the front end of the once-through nuclear fuel cycle. These processes include uranium mining, milling, refining, conversion, enrichment, and fuel fabrication. Metrics are developed to allow environmental impacts to be summed across the full set of front end processes, including transportation and disposition of the resulting depleted uranium.
Brett Carlsen; Emily Tavrides; Erich Schneider
CW Room Temperature Re-Buncher for the Project X Front End
At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The room temperature front end of the linac contains an ion source, an RFQ accelerator and a Medium Energy Beam Transport (MEBT) section comprising a high bandwidth bunch selective chopper. The MEBT length is about 10 m, so three re-bunching CW cavities are used to support the beam longitudinal dynamics. The paper reports a RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.
Romanov, Gennady; Awida, Mohamed H.; Chen, Meiyu; Gonin, Ivan V.; Kazakov, Sergey; Kostin, Roman; Lebedev, Valeri; Solyak, Nikolay; Yakovlev, Vyacheslav P.; /Fermilab
Apparatus and method for phase fronts based on superluminal polarization current
An apparatus and method for a radiation source involving phase fronts emanating from an accelerated, oscillating polarization current whose distribution pattern moves superluminally (that is, faster than light in vacuo). Theoretical predictions and experimental measurements using an existing prototype superluminal source show that the phase fronts from such a source can be made to be very complex. Consequently, it will be very difficult for an aircraft imaged by such a radiation to detect where this radiation has come from. Moreover, the complexity of the phase fronts makes it almost impossible for electronics on an aircraft to synthesize a rogue reflection. A simple directional antenna and timing system should, on the other hand, be sufficient for the radar operators to locate the aircraft, given knowledge of their own source's speed and modulation pattern.
Singleton, John (Los Alamos, NM); Ardavan, Houshang (Cambridge, GB); Ardavan, Arzhang (Cambridge, GB)
Dynamical model for longitudinal wave functions in light-front holographic QCD
We construct a Schr�dinger-like equation for the longitudinal wave function of a meson in the valence qq{sup -bar} sector, based on the �t Hooft model for large-N two-dimensional QCD, and combine this with the usual transverse equation from light-front holographic QCD, to obtain a model for mesons with massive quarks. The computed wave functions are compared with the wave function ansatz of Brodsky and de T�ramond and used to compute decay constants and parton distribution functions. The basis functions used to solve the longitudinal equation may be useful for more general calculations of meson states in QCD. -- Highlights: �Provide relativistic quark model based on light-front holographic QCD. �Incorporate dependence on quark mass. �Consistent with the Brodsky�de T�ramond quark-wave-function ansatz. �Compute meson decay constants and parton distribution functions. �Illustrate use of basis functions that could be convenient for more general numerical calculations in light-front QCD.
Chabysheva, Sophia S.; Hiller, John R., E-mail: email@example.com
Report on the value engineering workshop on APS beamline front ends
A formal value engineering evaluation process was developed to address the front end components of the beamlines for the Advanced Photon Source (APS). This process (described in Section 2) involved an information phase, a creative phase, a judgment phase, a development phase, and a recommendation phase. Technical experts from other national laboratories and industry were invited to a two-day Value Engineering Workshop on November 5-6, 1992. The results of this Workshop are described in Section 4. Following the Workshop, various actions by the APS staff led to the redesign of the front end components, which are presented in Sections 5 and 6. The cost benefit analysis is presented in Section 7. It is important of realize that an added benefit of the Workshop was to obtain numerous design evaluations and enhancements of the front end components by experts in the field. As the design work proceeds to Title II completion, the APS staff is including many of these suggestions.
Kuzay, T.
The Wave-Front Correction System for the Sunrise Balloon-Borne Solar Observatory
This paper describes the wave-front correction system developed for the Sunrise balloon telescope, and provides information about its in-flight performance. For the correction of low-order aberrations, a Correlating Wave-Front Sensor (CWS) was used. It consisted of a six-element Shack-Hartmann wave-front sensor (WFS), a fast tip-tilt mirror for the compensation of image motion, and an active telescope secondary mirror for focus correction. The CWS delivered a stabilized image with a precision of 0.04 arcsec (rms), whenever the coarse pointing was better than 90 arcsec peak-to-peak. The automatic focus adjustment maintained a focus stability of 0.01 waves in the focal plane of the CWS. During the 5.5 day flight, good image quality and stability was achieved during 33 hours, containing 45 sequences that lasted between 10 and 45 minutes.
Berkefeld, T; Soltau, D; Bell, A; Doerr, H P; Feger, B; Friedlein, R; Gerber, K; Heidecke, F; Kentischer, T; L�he, O v d; Sigwarth, M; W�lde, E; Barthol, P; Deutsch, W; Gandorfer, A; Germerott, D; Grauf, B; Meller, R; Alvarez-Herrero, A; Kn�lker, M; Pillet, V Martinez; Solanki, S K; Title, A M
Front-flash thermal imaging characterization of continuous fiber ceramic composites.
Infrared thermal imaging has become increasingly popular as a nondestructive evaluation method for characterizing materials and detecting defects. One technique, which was utilized in this study, is front-flash thermal imaging. We have developed a thermal imaging system that uses this technique to characterize advanced material systems, including continuous fiber ceramic composite (CFCC) components. In a front-flash test, pulsed heat energy is applied to the surface of a sample, and decay of the surface temperature is then measured by the thermal imaging system. CFCC samples with drilled flat-bottom holes at the back surface (to serve as ''flaws'') were examined. The surface-temperature/time relationship was analyzed to determine the depths of the flaws from the front surface of the CFCC material. Experimental results on carbon/carbon and CFCC samples are presented and discussed.
Deemer, C.
Front-end Electronics Test for the LHCb Muon Wire Chambers
This document describes the apparatus and procedures implemented to test Multi Wire Proportional Chambers (MWPC) after front-end assembly for the LHCb Muon Detector. Results of measurements of key noise parameters are also described. Given a fully equipped chamber, this system is able to diagnose every channel performing an analysis of front-end output drivers� response and noise rate versus threshold. Besides, it allows to assess if the noise rate at the experiment threshold region is within appropriate limits. Aiming at an automatic, fast and user-friendly system for mass production tests of MWPC, the project has foreseen as well electronic identification of every chamber and front-end board, and data archiving in such a way to make it available to the Experiment Control System (ECS) while in operation.
Nobrega, R; Carboni, G; Massafferri, A; Santovetti, E
AdS/QCD and Light Front Holography: A New Approximation to QCD
The combination of Anti-de Sitter space (AdS) methods with light-front holography leads to a semi-classical first approximation to the spectrum and wavefunctions of meson and baryon light-quark bound states. Starting from the bound-state Hamiltonian equation of motion in QCD, we derive relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. Its eigenvalues give the hadronic spectrum, and its eigenmodes represent the probability distribution of the hadronic constituents at a given scale. Applications to the light meson and baryon spectra are presented. The predicted meson spectrum has a string-theory Regge form M{sup 2} = 4{kappa}{sup 2}(n+L+S/2); i.e., the square of the eigenmass is linear in both L and n, where n counts the number of nodes of the wavefunction in the radial variable {zeta}. The space-like pion form factor is also well reproduced. One thus obtains a remarkable connection between the description of hadronic modes in AdS space and the Hamiltonian formulation of QCD in physical space-time quantized on the light-front at fixed light-front time {tau}. The model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms.
Brodsky, Stanley J.; de Teramond, Guy
Transient nature of salt movement with wetting front in an unsaturated soil
TRANSIENT NATURE OF SALT MOVEMENT WITH WETTING FRONT IN AN UNSATURATED SOIL A Thesis bY VISHWAS VINAYAK SOMAN Submitted to the Office of Graduate Studies of Texas A&M UniversitY in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1992 Major Subject: Agricultural Engineering TRANSIENT NATURE OF SALT MOVEMENT WITH WETTING FRONT IN AN UNSATURATED SOIL A Thesis VISHWAS VINAYAK SOMAN Approved as to style and content by: Marshall J. McFarland (Chair...
Soman, Vishwas Vinayak
Comparison of quantum field perturbation theory for the light front with the theory in lorentz coordinates
The relationship between the perturbation theory in light-front coordinates and Lorentz-covariant perturbation theory is investigated. A method for finding the difference between separate terms of the corresponding series without their explicit evaluation is proposed. A procedure of constructing additional counter-terms to the canonical Hamiltonian that compensate this difference at any finite order is proposed. For the Yukawa model, the light-front Hamiltonian with all of these counter-terms is obtained in a closed form. Possible application of this approach to gauge theories is discussed.
S. A. Paston; V. A. Franke
Upper and lower limits on the Crab pulsar's astrophysical parameters set from gravitational wave observations by LIGO: braking index and energy considerations
The Laser Interferometer Gravitational Observatory (LIGO) has recently reached the end of its fifth science run (S5), having collected more than a year worth of data. Analysis of the data is still ongoing but a positive detection of gravitational waves, while possible, is not realistically expected for most likely sources. This is particularly true for what concerns gravitational waves from known pulsars. In fact, even under the most optimistic (and not very realistic) assumption that all the pulsar's observed spin-down is due to gravitational waves, the gravitational wave strain at earth from all the known isolated pulsars (with the only notable exception of the Crab pulsar) would not be strong enough to be detectable by existing detectors. By August 2006, LIGO had produced enough data for a coherent integration capable to extract signal from noise that was weaker than the one expected from the Crab pulsar's spin-down limit. No signal was detected, but beating the spin-down limit is a considerable achievement for the LIGO Scientific Collaboration (LSC). It is customary to translate the upper limit on strain from a pulsar into a more astrophysically significant upper limit on ellipticity. Once the spin-down limit has been beaten, it is possible to release the constraint that all the spin-down is due to gravitational wave emission. A more complete model with diverse braking mechanisms can be used to set limits on several astrophysical parameters of the pulsar. This paper shows possible values of such parameters for the Crab pulsar given the current limit on gravitational waves from this neutron star.
Giovanni Santostasi
Stability of planar reactive fronts in external fields Arkady B. Rovinsky,* Anatol M. Zhabotinsky,
in reactive systems due to external fields such as electric fields or pressure gradients, may significantlyStability of planar reactive fronts in external fields Arkady B. Rovinsky,* Anatol M. Zhabotinsky arise naturally in systems sub- jected to external fields, such as electric fields or pressure gradients
Epstein, Irving R.
A discontinuous Galerkin front tracking method for two-phase flows with surface tension
A discontinuous Galerkin front tracking method for two-phase flows with surface tension Vinh with surface tension. �? 2009 Elsevier Ltd. All rights reserved. 1. Introduction Interfaces separating regions tension. In this case, the interface separates two different fluids and the effect of surface tension re
Peraire, Jaime
A front-tracking algorithm for accurate representation of surface tension
A front-tracking algorithm for accurate representation of surface tension Stephane Popinet particularly, we focus our attention on obtaining an accurate description of the surface-tension terms and the associated pressure jump. We consider the stationary Laplace solution for a bub- ble with surface tension
Frey, Pascal
Green radio despite "Dirty RF" front-end Myriam Ariaudo*1
Green radio despite "Dirty RF" front-end Myriam Ariaudo*1 , Inbar Fijalkow1 , Jean-Luc Gautier1 in order to contribute in a Green radio development. In fact, the effects of typical RF imperfections, like algorithms are applied. Such algorithms enable Green applications (e.g., Orthogonal Frequency Division
Fijalkow, Inbar
2 Bainitic Ferrite The growth of pearlite occurs at a common transformation front with the
2 Bainitic Ferrite The growth of pearlite occurs at a common transformation front with the austenite. The growth of the ferrite and cementite phases is coupled and their compositions are complementary since the carbon which cannot be accommodated by the ferrite is incorporated into the cementite
Cambridge, University of
Zero modes in the light-front coupled-cluster method
The light-front coupled-cluster (LFCC) method is a technique for solving Hamiltonian eigenvalue problems in light-front-quantized field theories. Its primary purpose is to provide a systematic sequence of solvable approximations to the original eigenvalue problem without the truncation of Fock space. Here we discuss the incorporation of zero modes, modes of zero longitudinal momentum, into the formalism of the method. Without zero modes, the light-front vacuum is trivial, and the vacuum expectation value of the field is always zero. The LFCC method with zero modes provides for vacuum structure, in the form of a generalized coherent state of zero modes, as is illustrated here in two-dimensional model field theories. -- Highlights: �Extends the light-front coupled-cluster method to include zero modes. �Illustrates with an analysis of vacuum structure for phi-3, phi-4, and Wick�Cutkosky model field theories. �Demonstrates the applicability of the LFCC method to theories with spontaneous symmetry breaking.
Export of Asian pollution during two cold front episodes of the TRACE-P experiment
Export of Asian pollution during two cold front episodes of the TRACE-P experiment C. Mari how these cyclonic systems have impacted the export of pollution out of the Asian continent. We of pollution are met during flight 13 (i.e., the occurrences of the warm conveyor belt near the source regions
Palmer, Paul
Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland
Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland Ian Glaciers, Greenland, from 2001 to 2006, a period in which they retreated and sped up. These data show and retreat in less than a century indicates that tidewater glaciers in Greenland can advance rapidly
Tsai, Victor C.
Numerical study of the diapycnal flow through a tidal front with passive tracers
. This qualitatively agrees with a recent field experiment using a dye tracer on Georges Bank. Additional experiments are performed to investigate the sensitivity of the tracer dispersion to the tidal phase and the location, the previous studies indicated Eulerian cross-front mean circu- lation maybe is in a multiple-cell structure
Dong, Changming "Charles"
Development of Novel Front Contract Pastes for Crystalline Silicon Solar Cells
In order to improve the efficiencies of silicon solar cells, paste to silicon contact formation mechanisms must be more thoroughly understood as a function of paste chemistry, wafer properties and firing conditions. Ferro Corporation has been involved in paste development for over 30 years and has extensive expertise in glass and paste formulations. This project has focused on the characterization of the interface between the top contact material (silver paste) and the underlying silicon wafer. It is believed that the interface between the front contact silver and the silicon wafer plays a dominant role in the electrical performance of the solar cell. Development of an improved front contact microstructure depends on the paste chemistry, paste interaction with the SiNx, and silicon (�Si�) substrate, silicon sheet resistivity, and the firing profile. Typical front contact ink contains silver metal powders and flakes, glass powder and other inorganic additives suspended in an organic medium of resin and solvent. During fast firing cycles glass melts, wets, corrodes the SiNx layer, and then interacts with underlying Si. Glass chemistry is also a critical factor in the development of an optimum front contact microstructure. Over the course of this project, several fundamental characteristics of the Ag/Si interface were documented, including a higher-than-expected distribution of voids along the interface, which could significantly impact electrical conductivity. Several techniques were also investigated for the interfacial analysis, including STEM, EDS, FIB, EBSD, and ellipsometry.
Duty, C.; Jellison, D. G.E. P.; Joshi, P.
Front propagation techniques to calculate the largest Lyapunov exponent of dilute hard disk gases
A kinetic approach is adopted to describe the exponential growth of a small deviation of the initial phase space point, measured by the largest Lyapunov exponent, for a dilute system of hard disks, both in equilibrium and in a uniform shear flow. We derive a generalized Boltzmann equation for an extended one-particle distribution that includes deviations from the reference phase space point. The equation is valid for very low densities n, and requires an unusual expansion in powers of 1/|ln n|. It reproduces and extends results from the earlier, more heuristic clock model and may be interpreted as describing a front propagating into an unstable state. The asymptotic speed of propagation of the front is proportional to the largest Lyapunov exponent of the system. Its value may be found by applying the standard front speed selection mechanism for pulled fronts to the case at hand. For the equilibrium case, an explicit expression for the largest Lyapunov exponent is given and for sheared systems we give explicit expressions that may be evaluated numerically to obtain the shear rate dependence of the largest Lyapunov exponent.
R. van Zon; H. van Beijeren
Fluid Dynamics Research 33 (2003) 173189 The distortion of weak fronts by mesoscale orography
University of Technology, Delft, NL c Environment Centre, University of Leeds, Leeds LS2 9JT, UK d Department the surface of the orography, that a narrow portion of the front eventually overturns, leading to enhanced and the localised overturning process is examined within an analytical framework. c 2003 Published by The Japan
Hunt, Julian
CSCI 3060U/ENGR 3980U -Winter 2013 Course Project Assignment #1 -Front End Requirements
and in true XP fashion represent those requirements as a set of requirements tests. Create and organize a complete set of requirements tests for the Front End of the Ticket Selling Service, to test for every required behaviour. Do not write any programs yet. Each test should be a complete test session input stream
Bradbury, Jeremy S.
Geodesic Remeshing Using Front Propagation Gabriel Peyre (firstname.lastname@example.com)
Geodesic Remeshing Using Front Propagation Gabriel Peyr´e (firstname.lastname@example.com) CMAP modeling and processing that uses only fast geodesic computations. The basic building block, an intrinsic algo- rithm for computing geodesic centroidal tessellations, and a fast and robust method
A FREEWARE PROGRAM FOR PRECISE OPTICAL ANALYSIS OF THE FRONT SURFACE OF A SOLAR CELL Simeon C. Baker-Finch and Keith R. McIntosh Centre for Sustainable Energy Systems, Australian National University, Canberra, ACT 0200, AUSTRALIA Tel: +61-2-6125-8966, Fax: +61-2-6125-8873, Email: simeon
of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the University of Wisconsin VolumeLIDAR OBSERVATIONS AND COMPARISON WITH NUMERICAL SIMULATION OF A LAKE MICHIGAN LAND BREEZE FRONT G circulation over Lake Michigan. Backscatter returns revealed a steady offshore flow extending 1.5 to 4 km
Eloranta, Edwin W.
Shack Hartmann wave-front measurement with a large F-number plastic microlens array
Hartmann wave-front sensor, deformable mirror. r 1996 Optical Society of America 1. Introduction In direct The improvement in laser irradiation uniformity of a spherical target is necessary for higher efficiency in the fusion reaction. In the laser system used for this purpose, large optical devices of several tens
Yoon, Geunyoung
Fronts in the Southwestern Gulf of Maine5 Nicholas W. Woods1,2
Autonomous Systems Laboratory,12 Physical Oceanography Department13 Woods Hole Oceanographic Institution14 15, and autonomous underwater glider observations. Density fronts are found throughout47 the southwestern GOM during inversely upon the time-integrated regional wind stress magnitude and49 the rate of river discharge
Fratantoni, David
Hierarchical Modelling of Automotive Sensor Front-Ends For Structural Diagnosis of Aging Faults
functions previously handled purely mechanical. In addition hybrid and pure electrical cars are emerging are hybrid and electrical cars. The automotive semiconductor elec- tronics market amounted to 19.5 billion for the development of dependable analogue/mixed-signal car front-ends, by interfacing aging models between different
Wieringa, Roel
ICE Professionals Limited Email: email@example.com Ph: (09) 557 1450 Front End Developer
ICE Professionals Limited Email: email@example.com Ph: (09) 557 1450 Front End Developer, this is the job for you. Responsibilities: Producing high quality HTML/CSS and JavaScript solutions. Providing to produce dynamic pages If you are interested in this role, send your CV and academic transcript to Dean
Sun, Jing
Front. Electr. Electron. Eng. DOI 10.1007/s11460-012-0170-6
both to perform inference and for learning. By contrast, machine learning techniques are often deFront. Electr. Electron. Eng. DOI 10.1007/s11460-012-0170-6 Alan YUILLE, Xuming HE Probabilistic machines (SVMs) and hence we reduce the learning to standard machine learning methods. We show that many
Yuille, Alan L.
CIAO-HELLO information Centre Helpdesk, front office, person-to-person interaction
CIAO-HELLO information Centre Helpdesk, front office, person-to-person interaction and welcome to foreign students 5th Erasmus Staff Mobility Week 2014 Rome 23rd - 27th, June 2014 #12;CIAO-HELLO of student experience exchanges A rise in the international scenario at Sapienza Pagina 224/06/2014CIAO-HELLO
Di Pillo, Gianni
ElEctromagnEtic analysis and testing Flap, inside Front cover
#12;ElEctromagnEtic analysis and testing Flap, inside Front cover Sandia National Laboratories, homeland security, nonproliferation, and industrial competitiveness. ElEctromagnEtic analysis and testing #12;ElEctromagnEtic analysis and testingElEctromagnEtic analysis and testing Technology that harnesses
Fuerschbach, Phillip
Silicon Solar Cells with Front Hetero-Contact and Aluminum Alloy Back Junction: Preprint
We prototype an alternative n-type monocrystalline silicon (c-Si) solar cell structure that utilizes an n/i-type hydrogenated amorphous silicon (a-Si:H) front hetero-contact and a back p-n junction formed by alloying aluminum (Al) with the n-type Si wafer.
Average crack front velocity during subcritical fracture propagation in a heterogeneous medium
Average crack front velocity during subcritical fracture propagation in a heterogeneous medium relaxation tests, exploring subcritical to critical regimes. Transparency of the material (PMMA) allows kinetic crack propagation is usually referred to as sub-critical crack growth or sub- critical regime
Asymmetry of Tidal Plume Fronts in an Eastern Boundary Current Regime
water mass. This vorticity controls the transition of the tidal plume 2 #12;front to a subcritical state bulge, which in turn is embedded in far-field plume and coastal waters. Because of the mixing caused on its upwind or northern side) and marks a transition from supercritical to subcritical flow for 6
Jay, David
|Low Graphics version Change edition | |About BBC News Feedback Help News Front Page
|Low Graphics version Change edition | |About BBC News Feedback Help News Front Page World UK by the International Atomic Energy Agency to mark 50 years of nuclear power. What the IAEA acknowledges as the world-mura, Japan Jet Kurchatov Institute International Atomic Energy Agency The BBC is not responsible
Sensitivity of mesoscale gravity waves to the baroclinicity of jet-front systems
To investigate the generation of mesoscale gravity waves from upper-tropospheric jet-front systems, five different life cycles of baroclinic waves are simulated with a high-resolution mesoscale model (MM5 with 10-km grid spacing). The baroclinicity...
Wang, Shuguang
A model-dye comparison experiment in the tidal mixing front zone on the southern flank of Georges Bank
A model-dye comparison experiment in the tidal mixing front zone on the southern flank of Georges; revised 8 June 2007; accepted 30 October 2007; published 9 February 2008. [1] A process-oriented model-dye the observed movement of dye across the tidal mixing front on the southern flank of Georges Bank during 22
Chen, Changsheng
Standing spin-wave mode structure and linewidth in partially disordered hexagonal arrays of perpendicularly magnetized sub-micron Permalloy discs
Standing spin wave mode frequencies and linewidths in partially disordered perpendicular magnetized arrays of sub-micron Permalloy discs are measured using broadband ferromagnetic resonance and compared to analytical results from a single, isolated disc. The measured mode structure qualitatively reproduces the structure expected from the theory. Fitted demagnetizing parameters decrease with increasing array disorder. The frequency difference between the first and second radial modes is found to be higher in the measured array systems than predicted by theory for an isolated disc. The relative frequencies between successive spin wave modes are unaffected by reduction of the long-range ordering of discs in the array. An increase in standing spin wave resonance linewidth at low applied magnetic fields is observed and grows more severe with increased array disorder.
Ross, N., E-mail: email@example.com; Kostylev, M., E-mail: firstname.lastname@example.com [School of Physics, University of Western Australia, Crawley, WA (Australia); Stamps, R. L. [School of Physics, University of Western Australia, Crawley, WA (Australia); SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)
Light-Front Quantization and AdS/QCD: An Overview
We give an overview of the light-front holographic approach to strongly coupled QCD, whereby a confining gauge theory, quantized on the light front, is mapped to a higher-dimensional anti de Sitter (AdS) space. The framework is guided by the AdS/CFT correspondence incorporating a gravitational background asymptotic to AdS space which encodes the salient properties of QCD, such as the ultraviolet conformal limit at the AdS boundary at z {yields} 0, as well as modifications of the geometry in the large z infrared region to describe confinement and linear Regge behavior. There are two equivalent procedures for deriving the AdS/QCD equations of motion: one can start from the Hamiltonian equation of motion in physical space time by studying the off-shell dynamics of the bound state wavefunctions as a function of the invariant mass of the constituents. To a first semiclassical approximation, where quantum loops and quark masses are not included, this leads to a light-front Hamiltonian equation which describes the bound state dynamics of light hadrons in terms of an invariant impact variable {zeta} which measures the separation of the partons within the hadron at equal light-front time. Alternatively, one can start from the gravity side by studying the propagation of hadronic modes in a fixed effective gravitational background. Both approaches are equivalent in the semiclassical approximation. This allows us to identify the holographic variable z in AdS space with the impact variable {zeta}. Light-front holography thus allows a precise mapping of transition amplitudes from AdS to physical space-time. The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role.
de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC /Stanford U., Phys. Dept.
Histologic Comparison of Regenerate Bone Produced from Dentate Versus Edentulous Transport Discs in Bone Transport Distraction Osteogenesis
i HISTOLOGIC COMPARISON OF REGENERATE BONE PRODUCED FROM DENTATE VERSUS EDENTULOUS TRANSPORT DISCS IN BONE TRANSPORT DISTRACTION OSTEOGENESIS A Thesis by CARLOS SEVILLA GAIT�N Submitted to The Office of Graduate and Professional Studies... Paul Dechow Head of Department, William W. Nagy December 2013 Major Subject: Oral Biology Copyright 2013 Carlos Sevilla Gaitan ii ABSTRACT Purpose: The purpose of this research was to quantify the number of blood vessels...
Sevilla Gaitan, Carlos
Solar Space Density of the Red Clump Stars and the Scale-length of the Thin Disc
We estimated the scale-length of the thin disc with the J and W1 magnitudes of the most probable Red Clump (RC) stars in the Galactic plane, $-0\\overset{^\\circ}.5 \\leq b \\leq +0\\overset{^\\circ}.5$, in 19 equal sized fields with consecutive Galactic longitudes which cover the interval $90^\\circ \\leq l \\leq 270^\\circ$. Our results are constrained with respect to the solar space density ($D^*=5.95$), which indicates that the radial variation of the density is lower for higher Galactocentric distances. The scale-length of the thin disc is 2 kpc for the fields in the Galactic anticentre direction or close to this direction, while it decreases continuously in the second and third quadrants reaching to a lower limit of $h$ = 1.6 kpc at the Galactic longitudes $l$ = 90$^\\circ$ and $l$ = 270$^\\circ$. The distribution of the scale-length in 19 fields is consistent with the predictions from the Galaxia model and its variation with longitude is probably due to the inhomogeneity structure of the disc caused by the accrete...
Gokce, E Yaz; Duran, S; Bilir, S; Yalcinkaya, A; Ak, S; Ak, T; Lopez-Corredoira, M; Cabrera-Lavers, A
October 1999 1999, Elsevier Science Inc., 1040-6190/99/$see front matter PII S1040-6190(99)00074-3 77 Transmission Rights and
October 1999 © 1999, Elsevier Science Inc., 1040-6190/99/$see front matter PII S1040., 1040-6190/99/$see front matter PII S1040-6190(99)00074-3 The Electricity Journal Much
Kammen, Daniel M.
1359-6446/02/$ see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: DDT Vol. 7, No. 18 (Suppl.), 2002
1359-6446/02/$ see front matter ©2002 Elsevier Science Ltd. All rights reserved. PII: DDT Vol. 7
Sabatini, David M.
Transient moisture migration and phase change front propagation in porous media
The process of transient moisture migration in a semi-infinite slab of porous concrete being heated at one side has been analyzed. The model solves the heat and mass transfer equations considering water and air migration in the concrete, including evaporation and recondensation effects. The domain is subdivided into a dry region and a wet region, with the phase-change-front motion being modeled via mass and energy conservation at the front. Approximate solutions are obtained by use of a similarity transformation and numerical integration of the resulting ordinary differential equations. Typical results and parametric evaluations are given for the cases of an impermeable outer surface as well as an outer surface exposed to ambient pressure.
Shiina, Y.; Kroeger, P.G.
Engineering Spectral Control Using Front Surface Filters for Maximum TPV Energy Conversion System Performance
Energy conversion efficiencies of better than 23% have been demonstrated for small scale tests of a few thermophotovoltaic (TPV) cells using front surface, tandem filters [1, 2]. The engineering challenge is to build this level of efficiency into arrays of cells that provide useful levels of energy. Variations in cell and filter performance will degrade TPV array performance. Repeated fabrication runs of several filters each provide an initial quantification of the fabrication variation for front surface, tandem filters for TPV spectral control. For three performance statistics, within-run variation was measured to be 0.7-1.4 percent, and run-to-run variation was measured to be 0.5-3.2 percent. Fabrication runs using a mask have been shown to reduce variation across interference filters from as high as 8-10 percent to less than 1.5 percent. Finally, several system design and assembly approaches are described to further reduce variation.
T Rahmlow, Jr; J Lazo-Wasem, E Gratrix; J Azarkevich; E Brown; D DePoy; D Eno; P Fourspring; J Parrington; R Mahorter; B Wernsman
Energy conversion efficiencies of better than 23% have been demonstrated for small scale tests of a few thermophotovoltaic (TPV) cells using front surface, tandem filters [1,2]. The engineering challenge is to build this level of efficiency into arrays of cells that provide useful levels of energy. Variations in cell and filter performance will degrade TPV array performance. Repeated fabrication runs of several filters each provide an initial quantification of the fabrication variation for front surface, tandem filters for TPV spectral control. For three performance statistics, within-run variation was measured to be 0.7-1.4 percent, and run-to-run variation was measured to be 0.5-3.2 percent. Fabrication runs using a mask have been shown to reduce variation across interference filters from as high 8-10 percent to less than 1.5 percent. Finally, several system design and assembly approaches are described to further reduce variation.
TD Rahmlaw, Jr; JE Lazo-Wasem; EJ Gratrix; JJ Azarkevich; EJ Brown; DM DePoy; DR Eno; PM Fourspring; JR Parrington; RG Mahorter; B Wernsman
Light-Front Holography and Gauge/Gravity Duality: The Light Meson and Baryon Spectra
Starting from the bound state Hamiltonian equation of motion in QCD, we derive relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. Its eigenvalues give the hadronic spectrum, and its eigenmodes represent the probability amplitudes of the hadronic constituents at a given scale. An effective classical gravity description in a positive-sign dilaton background exp(+{kappa}{sup 2}z{sup 2}) is given for the phenomenologically successful soft-wall model which naturally encodes the internal structure of hadrons and their orbital angular momentum. Applications to the light meson and baryon spectrum are presented.
On relation between rest frame and light-front descriptions of quarkonium
In this paper we study the relation between the light-front (infinite momentum) and rest-frame descriptions of quarkonia. While the former is more convenient for high-energy production, the latter is usually used for the evaluation of charmonium properties. In particular, we discuss the dynamics of a relativistically moving system with nonrelativistic internal motion and give relations between rest frame and light-front potentials used for the description of quarkonium states. We consider two approximations, first the small coupling regime, and next the nonperturbative small binding energy approximation. In both cases we get consistent results. Our results could be relevant for the description of final state interactions in a wide class of processes, including quarkonium production on nuclei and plasma. Moreover, they can be extended to the description of final state interactions in the production of weakly bound systems, such as for example the deuteron.
B. Z. Kopeliovich; E. Levin; Ivan Schmidt; M. Siddikov
Kopeliovich, B Z; Schmidt, Ivan; Siddikov, M
Wave fronts, pulses and wave trains in photoexcited superlattices behaving as excitable or oscillatory media
Undoped and strongly photoexcited semiconductor superlattices with field-dependent recombination behave as excitable or oscillatory media with spatially discrete nonlinear convection and diffusion. Infinitely long, dc-current-biased superlattices behaving as excitable media exhibit wave fronts with increasing or decreasing profiles, whose velocities can be calculated by means of asymptotic methods. These superlattices can also support pulses of the electric field. Pulses moving downstream with the flux of electrons can be constructed from their component wave fronts, whereas pulses advancing upstream do so slowly and experience saltatory motion: they change slowly in long intervals of time separated by fast transitions during which the pulses jump to the previous superlattice period. Photoexcited superlattices can also behave as oscillatory media and exhibit wave trains.
J. I. Arana; L. L. Bonilla; H. T. Grahn
High-power, low-lateral divergence broad area quantum cascade lasers with a tilted front facet
We introduce a simple technique to improve the beam quality of broad area quantum cascade lasers. Moderately tilted front facets of the laser provide suppression of higher order lateral waveguide modes. A device with a width of 60??m and a front facet angle of 17� shows a nearly diffraction limited beam profile. In addition, the peak output power and the slope efficiency of the device are increased since most of the light inside the cavity is emitted through the tilted front facet by an asymmetric light intensity distribution along the cavity.
Ahn, Sangil, E-mail: email@example.com; Schwarzer, Clemens; Zederbauer, Tobias; MacFarland, Donald C.; Detz, Hermann; Andrews, Aaron M.; Schrenk, Werner; Strasser, Gottfried [Institute for Solid State Electronics, Vienna University of Technology, 1040 Vienna (Austria)
AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling
The combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states. The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. The eigenvalues give the hadronic spectrum, and the eigenmodes represent the probability distributions of the hadronic constituents at a given scale. A positive-sign confining dilaton background modifying AdS space gives a very good account of meson and baryon spectroscopy and form factors. The light-front holographic mapping of this model also leads to a non-perturbative effective coupling {alpha}{sub s}{sup Ads} (Q{sup 2}) which agrees with the effective charge defined by the Bjorken sum rule and lattice simulations. It displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of the full {beta}-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD.
Brodsky, Stanley J.; /SLAC; de Teramond, Guy; /Costa Rica U.; Deur, Alexandre; /Jefferson Lab
AdS/CFT and Light-Front Holography: A Theory of Strong Interactions
Recent developments in the theory of strong interactions are discussed in the framework of the AdS/CFT duality between string theories of gravity in a higher dimension Anti-de Sitter space and conformal quantum field theories in physical space-time. This novel theoretical approach, combined with 'light-front holography', leads to new insights into the quark and gluon structure of hadrons and a viable first approximation to quantum chromodynamics, the fundamental theory of the strong and nuclear interactions.
Brodsky, Stanley J.; /SLAC; Teramond, Guy F.de; /Costa Rica U.
report 2013 Front cover image: Greenough River Solar Farm, Western Australia.
R heAtinG 59 WinD PoWeR 65 appendiCes 65 APPenDiX 1: toP 10 SolAR PoStCoDeS by StAte 68 APPenDiX 2 #12. From jobs and investment in regional areas to solar panels, solar hot water and high efficiencyClean energy australia report 2013 #12;Front cover image: Greenough River Solar Farm, Western
Green, Donna
Method and apparatus for generating radiation utilizing DC to AC conversion with a conductive front
Method and apparatus for generating radiation of high power, variable duration and broad tunability over several orders of magnitude from a laser-ionized gas-filled capacitor array. The method and apparatus convert a DC electric field pattern into a coherent electromagnetic wave train when a relativistic ionization front passes between the capacitor plates. The frequency and duration of the radiation is controlled by the gas pressure and capacitor spacing.
Dawson, John M. (Pacific Palisades, CA); Mori, Warren B. (Hermosa Beach, CA); Lai, Chih-Hsiang (So. Pasadena, CA); Katsouleas, Thomas C. (Malibu, CA)
Method and apparatus ar disclosed for generating radiation of high power, variable duration and broad tunability over several orders of magnitude from a laser-ionized gas-filled capacitor array. The method and apparatus convert a DC electric field pattern into a coherent electromagnetic wave train when a relativistic ionization front passes between the capacitor plates. The frequency and duration of the radiation is controlled by the gas pressure and capacitor spacing. 4 figs.
Dawson, J.M.; Mori, W.B.; Lai, C.H.; Katsouleas, T.C.
On the metallicity of the Milky Way thin disc and photometric abundance scales
The mean metallicity of the Milky Way thin disc in the solar neighbourhood is still a matter of debate, and has recently been subject to upward revision (Haywood, 2001). Our star sample was drawn from a set of solar neighbourhood dwarfs with photometric metallicities. In a recent study, Reid (2002) suggests that our metallicity calibration, based on Geneva photometry, is biased. We show here that the effect detected by Reid is not a consequence of our adopted metallicity scale, and we confirm that our findings are robust. On the contrary, the application to Stromgren photometry of the Schuster & Nissen metallicity scale is problematic. Systematic discrepancies of about 0.1 to 0.3 dex affect the photometric metallicity determination of metal rich stars, on the colour interval 0.22< b-y <0.59, i.e including F and G stars. For F stars, it is shown that this is a consequence of a mismatch between the standard sequence m_1(b-y) of the Hyades used by Schuster & Nissen to calibrate their metallicity scale, and the system of Olsen (1993, 1994ab). It means that although Schuster & Nissen calibration and Olsen photometry are intrinsically correct, there are mutually incompatible for metal rich, F-type stars. For G stars, the discrepancy is most probably the continuation of the same problem, albeit worthen by the lack of spectroscopic calibrating stars. A corrected calibration is proposed which renders the calibration of Schuster & Nissen applicable to the catalogues of Olsen. We also give a simpler calibration referenced to the Hyades sequence, valid over the same color and metallicity ranges.
M. Haywood
Resource intensities of the front end of the nuclear fuel cycle
This paper presents resource intensities, including direct and embodied energy consumption, land and water use, associated with the processes comprising the front end of the nuclear fuel cycle. These processes include uranium extraction, conversion, enrichment, fuel fabrication and depleted uranium de-conversion. To the extent feasible, these impacts are calculated based on data reported by operating facilities, with preference given to more recent data based on current technologies and regulations. All impacts are normalized per GWh of electricity produced. Uranium extraction is seen to be the most resource intensive front end process. Combined, the energy consumed by all front end processes is equal to less than 1% of the electricity produced by the uranium in a nuclear reactor. Land transformation and water withdrawals are calculated at 8.07 m{sup 2} /GWh(e) and 1.37x10{sup 5} l/GWh(e), respectively. Both are dominated by the requirements of uranium extraction, which accounts for over 70% of land use and nearly 90% of water use.
Schneider, E.; Phathanapirom, U. [The University of Texas at Austin, 1 University Station C2200, Austin TX 78712 (United States); Eggert, R.; Collins, J. [Colorado School of Mines, 1500 Illinois St., Golden CO 80401 (United States)
Delayed muons in extensive air showers and double-front showers
The results of a long-term experiment performed in the period between 1995 and 2006 with the aid of the MUON-T underground (20 mwe) scintillation facility arranged at the Tien Shan mountain research station at an altitude of 3340 m above sea level are presented. The time distribution of delayed muons with an energy in excess of 5 GeV in extensive air showers of energy not lower than 106 GeV with respect to the shower front was obtained with a high statistical significance in the delay interval between 30 and 150 ns. An effect of the geomagnetic field in detecting delayed muons in extensive air showers was discovered. This effect leads to the asymmetry of their appearance with respect to the north-south direction. The connection between delayed muons and extensive air showers featuring two fronts separated by a time interval of several tens of to two hundred nanoseconds is discussed. This connection gives sufficient grounds to assume that delayed muons originate from the decays of pions and kaons produced in the second, delayed, front of extensive air showers.
Beisembaev, R. U.; Vavilov, Yu. N., E-mail: email@example.com; Vildanov, N. G.; Kruglov, A. V.; Stepanov, A. V. [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation); Takibaev, J. S. [Al-Farabi Kazakh National University (Kazakhstan)
Design of a Portable Test Facility for the ATLAS Tile Calorimeter Front-End Electronics Verification
The stand-alone test-bench deployed in the past for the verification of the Tile Calorimeter (TileCal) front-end electronics is reaching the end of its life cycle. A new version of the test-bench has been designed and built with the aim of improving the portability and exploring new technologies for future versions of the TileCal read-out electronics. An FPGA based motherboard with an embedded hardware processor and a few dedicated daughter-boards are used to implement all the functionalities needed to interface with the front-end electronics (TTC, G-Link, CANbus) and to verify the functionalities using electronic signals and LED pulses. The new device is portable and performs well, allowing the validation in realistic conditions of the data transmission rate. We discuss the system implementation and all the tests required to gain full confidence in the operation of the front-end electronics of the TileCal in the ATLAS detector.
Kim, H Y; The ATLAS collaboration; Carrio, F; Moreno, P; Masike, T; Reed, R; Sandrock, C; Schettino, V; Shalyugin, A; Solans, C; Souza, J; Suter, R; Usai, G; Valero, A
H-Morph: An indirect approach to advancing front hex meshing
H-Morph is a new automatic algorithm for the generation of a hexahedral-dominant finite element mesh for arbitrary volumes. The H-Morph method starts with an initial tetrahedral mesh and systematically transforms and combines tetrahedral into hexahedra. It uses an advancing front technique where the initial front consists of a set of prescribed quadrilateral surface facets. Fronts are individually processed by recovering each of the six quadrilateral faces of a hexahedron from the tetrahedral mesh. Recovery techniques similar to those used in boundary constrained Delaunay mesh generation are used. Tetrahedral internal to the six hexahedral faces are then removed and a hexahedron is formed. At any time during the H-Morph procedure a valid mixed hexahedral-tetrahedral mesh is in existence within the volume. The procedure continues until no tetrahedral remain within the volume, or tetrahedral remain which cannot be transformed or combined into valid hexahedral elements. Any remaining tetrahedral are typically towards the interior of the volume, generally a less critical region for analysis. Transition from tetrahedral to hexahedra in the final mesh is accomplished through pyramid shaped elements. Advantages of the proposed method include its ability to conform to an existing quadrilateral surface mesh, its ability to mesh without the need to decompose or recognize special classes of geometry, and its characteristic well-aligned layers of elements parallel to the boundary. Example test cases are presented on a variety of models.
FBI Fingerprint Image Capture System High-Speed-Front-End throughput modeling
The Federal Bureau of Investigation (FBI) has undertaken a major modernization effort called the Integrated Automated Fingerprint Identification System (IAFISS). This system will provide centralized identification services using automated fingerprint, subject descriptor, mugshot, and document processing. A high-speed Fingerprint Image Capture System (FICS) is under development as part of the IAFIS program. The FICS will capture digital and microfilm images of FBI fingerprint cards for input into a central database. One FICS design supports two front-end scanning subsystems, known as the High-Speed-Front-End (HSFE) and Low-Speed-Front-End, to supply image data to a common data processing subsystem. The production rate of the HSFE is critical to meeting the FBI`s fingerprint card processing schedule. A model of the HSFE has been developed to help identify the issues driving the production rate, assist in the development of component specifications, and guide the evolution of an operations plan. A description of the model development is given, the assumptions are presented, and some HSFE throughput analysis is performed.
Rathke, P.M.
Svendborg Brakes | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartmentAUDIT REPORTOpenWende NewSowitec do Brasil EnergiaSur de RenovablesPvt Ltd
Section: Front
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administrationcontroller systemsBi (2) SrEvaluating the Seasonalsw ' b 0 % bP. May, G.J. Kim
Front cover
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsing ZirconiaPolicyFeasibilityFieldMinds"OfficeTourFrom clustersMon,
Feasibility and electromagnetic compatibility study of the ClearPEM front-end electronics for simultaneous PET-MR imaging
electromagnetic interference (EMI) effects between both systems were evaluated on a 7 T magnet by characterizing. Materials and methods The mutual electromagnetic interference tests between Clear- PEM front-end electronics
Dalang, Robert C.
The structure of a combustion front propagating in a fixed bed of crushed oil shale : co-current configuration.
??La propagation d'un front de combustion au sein d'un milieu poreux r�actif met en �uvre des m�canismes thermiques, chimiques et de transfert, avec de forts� (more)
Ferreira Martins, Marcio
FPI (Islamic Defenders' Front): the Making of a Violent Islamist Movement in the New Democracy of Indonesia
The current study is aimed at investigating the puzzle of why FPI (Islamic Defenders' Front) has chosen to adopt violent strategies within the democratic context of Indonesia. Much of literature on social movements suggests that democracy...
Recursion relations for multi-gluon off-shell amplitudes on the light-front and Wilson lines
We analyze the off-shell scattering amplitudes in the framework of the light-front perturbation theory. It is shown that the previously derived recursion relation between tree level off-shell amplitudes in this formalism actually resums whole classes of graphs into a Wilson line. More precisely, we establish a correspondence between the light-front methods for the computation of the off-shell amplitudes and the approach which makes use of the matrix elements of straight infinite Wilson lines, which are manifestly gauge invariant objects. Furthermore, since it is needed to explicitly verify the gauge invariance of light-front amplitudes, it is demonstrated that the Ward identities in this framework need additional instantaneous terms in the light-front graphs.
C. Cruz-Santiago; P. Kotko; A. Stasto
Cruz-Santiago, C; Stasto, A
Two: Standing in Front of the California Ballot-Box Train: The Present and Past of Ballot-Box Budgeting
OF THE CALIFORNIA BALLOT TRAIN: THE PRESENT AND PAST OFcan join and jump on the train. No. 2, they can go and stay3, they get in front of the train. And you know what happens
Mitchell, Daniel J.B.; Hirsch, Werner Z.
Wilson Bull., 110(3), 1998, pp. 352-361 VOCALIZATIONS OF THE BLUE-FRONTED AMAZON
of increasing interactions between individuals. The frequency containing the greatest amount of energy-fronted Amazon (Amazona aes- tiva) is a parrot whose distribution extends over northeastern Brazil, Bolivia
Fern�ndez-Juricic, Esteban
Light-induced disassembly of dusty bodies in inner protoplanetary discs: implications for the formation of planets
Laboratory experiments show that a solid-state greenhouse effect in combination with thermophoresis can efficiently erode a dust bed in a low-pressure gaseous environment. The surface of an illuminated, light absorbing dusty body is cooler than the dust below the surface (solidstate greenhouse effect). This temperature gradient leads to a directed momentum transfer between gas and dust particles and the dust particles are subject to a force towards the surface(thermophoresis). If the thermophoretic force is stronger than gravity and cohesion, dust particles are ejected. Applied to protoplanetary discs, dusty bodies smaller than several kilometres in size which are closer to a star than about 0.4 au are subject to a rapid and complete disassembly to submillimetre size dust aggregates by this process. While an inward-drifting dusty body is destroyed, the generated dust is not lost for the disc by sublimation or subsequent accretion on to the star but can be reprocessed by photophoresis or radiation pressure. Planetesimals cannot originate through aggregation of dust inside the erosion zone. If objects larger than several kilometres already exist, they prevail and further grow by collecting dust from disassembled smaller bodies. The pile-up of solids in a confined inner region of the disc, in general, boosts the formation of planets. Erosion is possible in even strongly gas-depleted inner regions as observed for TW Hya. Reprocessing of dust through light-induced erosion offers one possible explanation for growth of large cores of gas-poor giant planets in a gas-starved region as recently found around HD 149026b.
Gerhard Wurm
Front-End Board with Cyclone V as a Test High-Resolution Platform for the Auger-Beyond-2015 Front End Electronics
The surface detector (SD) array of the Pierre Auger Observatory containing at present 1680 water Cherenkov detectors spread over an area of 3000 km^2 started to operate since 2004. The currently used Front-End Boards are equipped with no-more produced ACEX and obsolete Cyclone FPGA (40 MSps/15-bit of dynamic range). Huge progress in electronics and new challenges from physics impose a significant upgrade of the SD electronics either to improve a quality of measurements (much higher sampling and much wider dynamic range) or pick-up from a background extremely rare events (new FPGA algorithms based on sophisticated approaches like e.g. spectral triggers or neural networks). Much higher SD sensitivity is necessary to confirm or reject hypotheses critical for a modern astrophysics. The paper presents the Front-End Board (FEB) with the biggest Cyclone V E FPGA 5CEFA9F31I7N, supporting 8 channels sampled with max. 250 MSps @ 14-bit resolution. Considered sampling for the SD is 120 MSps, however, the FEB has been developed with external anti-aliasing filters to keep a maximal flexibility. Six channels are targeted to the SD, two the rest for other experiments like: Auger Engineering Radio Array and additional muon counters. The FEB is an intermediate design pluged-in the actually used Unified Board communicating with micro-controller at 40 MHz, however providing even 250 MSPs sampling with 20-bit dynamic range, equipped in a virtual NIOS processor and supporting 256 MB of SDRAM as well as with an implemented spectral trigger based on the Discrete Cosine Transform for a detection of very inclined "old" showers. The FEB can also support a neural network developing for a detection of "young" showers, potentially generated by neutrinos.
Zbigniew Szadkowski
The Central American cold surge: an observational analysis of the deep southward penetration of North American cold fronts
THE CENTRAL AMERICAN COLD SURGE: AN OBSERVATIONAL ANALYSIS OF THE DEEP SOUTHWARD PENETRATION OF NORTH AMERICAN COLD FRONTS A Thesis by PHILIP JOHN REDING Submitted to the Office of Graduate Studies of Texas A &M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1992 Major Subject: Meteorology THE CENTRAL AMERICAN COLD SURGE: AN OBSERVATIONAL ANALYSIS OF THE DEEP SOUTHWARD PENETRATION OF NORTH AMERICAN COLD FRONTS A Thesis by PHILIP...
Reding, Philip John
Oxygen, {\\alpha}-element and iron abundance distributions in the inner part of the Galactic thin disc
We derived elemental abundances in 27 Cepheids, the great majority situated within a zone of Galactocentric distances ranging from 5 to 7 kpc. One star of our sample, SU Sct, has a Galactocentric distance of about 3 kpc, and thus falls in a poorly investigated region of the inner thin disc. Our new results, combined with data on abundances in the very central part of our Galaxy taken from literature, show that iron, magnesium, silicon, sulfur, calcium and titanium LTE abundance radial distributions, as well as NLTE distribution of oxygen reveal a plateau-like structure or even positive abundance gradient in the region extending from the Galactic center to about 5 kpc.
Martin, R P; Kovtyukh, V V; Korotin, S A; Yegorova, I A; Saviane, Ivo
The morphology of the Milky Way - II. Reconstructing CO maps from disc galaxies with live stellar distributions
The arm structure of the Milky Way remains somewhat of an unknown, with observational studies hindered by our location within the Galactic disc. In the work presented here we use smoothed particle hydrodynamics (SPH) and radiative transfer to create synthetic longitude-velocity observations. Our aim is to reverse-engineer a top down map of the Galaxy by comparing synthetic longitude-velocity maps to those observed. We set up a system of N-body particles to represent the disc and bulge, allowing for dynamic creation of spiral features. Interstellar gas, and the molecular content, is evolved alongside the stellar system. A 3D-radiative transfer code is then used to compare the models to observational data. The resulting models display arm features that are a good reproduction of many of the observed emission structures of the Milky Way. These arms however are dynamic and transient, allowing for a wide range of morphologies not possible with standard density wave theory. The best fitting models are a much better...
Pettitt, Alex R; Acreman, David M; Bate, Matthew R
Laboratory experiments show that a solid-state greenhouse effect in combination with thermophoresis can efficiently erode a dust bed in a low-pressure gaseous environment. The surface of an illuminated, light absorbing dusty body is cooler than the dust below the surface (solidstate greenhouse effect). This temperature gradient leads to a directed momentum transfer between gas and dust particles and the dust particles are subject to a force towards the surface(thermophoresis). If the thermophoretic force is stronger than gravity and cohesion, dust particles are ejected. Applied to protoplanetary discs, dusty bodies smaller than several kilometres in size which are closer to a star than about 0.4 au are subject to a rapid and complete disassembly to submillimetre size dust aggregates by this process. While an inward-drifting dusty body is destroyed, the generated dust is not lost for the disc by sublimation or subsequent accretion on to the star but can be reprocessed by photophoresis or radiation pressure. Pl...
Wurm, Gerhard
Percutaneous Transcatheter One-Step Mechanical Aortic Disc Valve Prosthesis Implantation: A Preliminary Feasibility Study in Swine
Purpose. To evaluate the feasibility of one-step implantation of a new type of stent-based mechanical aortic disc valve prosthesis (MADVP) above and across the native aortic valve and its short-term function in swine with both functional and dysfunctional native valves. Methods. The MADVP consisted of a folding disc valve made of silicone elastomer attached to either a nitinol Z-stent (Z model) or a nitinol cross-braided stent (SX model). Implantation of 10 MADVPs (6 Z and 4 SX models) was attempted in 10 swine: 4 (2 Z and 2 SX models) with a functional native valve and 6 (4 Z and 2 SX models) with aortic regurgitation induced either by intentional valve injury or by MADVP placement across the native valve. MADVP function was observed for up to 3 hr after implantation. Results. MADVP implantation was successful in 9 swine. One animal died of induced massive regurgitation prior to implantation. Four MADVPs implanted above functioning native valves exhibited good function. In 5 swine with regurgitation, MADVP implantation corrected the induced native valve dysfunction and the device's continuous good function was observed in 4 animals. One MADVP (SX model) placed across native valve gradually migrated into the left ventricle. Conclusion. The tested MADVP can be implanted above and across the native valve in a one-step procedure and can replace the function of the regurgitating native valve. Further technical development and testing are warranted, preferably with a manufactured MADVP.
Sochman, Jan [Institute for Clinical and Experimental Medicine, Intensive Care Unit, Clinic of Cardiology (Czech Republic)], E-mail: email@example.com; Peregrin, Jan H.; Rocek, Miloslav [Institute for Clinical and Experimental Medicine, Department of Diagnostic and Interventional Radiology (Czech Republic); Timmermans, Hans A.; Pavcnik, Dusan; Roesch, Josef [Oregon Health and Sciences University, Dotter Interventional Institute (United States)
Performance of the Fully Digital FPGA-based Front-End Electronics for the GALILEO Array
In this work we present the architecture and results of a fully digital Front End Electronics (FEE) read out system developed for the GALILEO array. The FEE system, developed in collaboration with the Advanced Gamma Tracking Array (AGATA) collaboration, is composed of three main blocks: preamplifiers, digitizers and preprocessing electronics. The slow control system contains a custom Linux driver, a dynamic library and a server implementing network services. The digital processing of the data from the GALILEO germanium detectors has demonstrated the capability to achieve an energy resolution of 1.53 per mil at an energy of 1.33 MeV.
D. Barrientos; M. Bellato; D. Bazzacco; D. Bortolato; P. Cocconi; A. Gadea; V. Gonz�lez; M. Gulmini; R. Isocrate; D. Mengoni; A. Pullia; F. Recchia; D. Rosso; E. Sanchis; N. Toniolo; C. A. Ur; J. J. Valiente-Dob�n
On the ion front of a plasma expanding into a vacuum
Calculations are reported on the expansion of a plasma into a vacuum, using a model of cold ions and Boltzmann electrons. The initial distribution of the ions at the edge of the plasma greatly affects the subsequent expansion. An initial abrupt drop of ion density leads to an expansion in which the abrupt drop is maintained. A finite slope, however, leads to the formation of a peak of ion density at the ion front. The subsequent behaviour may lead to wave breaking and the formation of multi-valued ion velocity distributions.
Allen, J. E. [OCIAM, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom) [OCIAM, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); University College, Oxford, Oxford OX1 4BH (United Kingdom); Perego, M. [Department of Scientific Computing, Florida State University, Tallahassee, Florida 32306 (United States)] [Department of Scientific Computing, Florida State University, Tallahassee, Florida 32306 (United States)
Light-front quantum chromodynamics: A framework for the analysis of hadron physics
An outstanding goal of physics is to find solutions that describe hadrons in the theory of strong interactions, Quantum Chromodynamics (QCD). For this goal, the light-front Hamiltonian formulation of QCD (LFQCD) is a complementary approach to the well-established lattice gauge method. LFQCD offers access to the hadrons nonperturbative quark and gluon amplitudes, which are directly testable in experiments at forefront facilities. We present an overview of the promises and challenges of LFQCD in the context of unsolved issues in QCD that require broadened and accelerated investigation. We identify specific goals of this approach and address its quantifiable uncertainties.
Bakker, B. L.G.; Bassetto, A.; Brodsky, S. J.; Broniowski, W.; Dalley, S.; Frederico, T.; Glazek, S. D.; Hiller, J. R.; Ji, C. -R.; Karmanov, V.; Kulshreshtha, D.; Mathiot, J. -F.; Melnitchouk, W.; Miller, G. A.; Papavassiliou, J.; Polyzou, W. N.; Stefanis, N.; Vary, J. P.; Ilderton, A.; Heinzl, T.
Quantum feedback cooling of a single trapped ion in front of a mirror
We develop a theory of quantum feedback cooling of a single ion trapped in front of a mirror. By monitoring the motional sidebands of the light emitted into the mirror mode we infer the position of the ion, and act back with an appropriate force to cool the ion. We derive a feedback master equation along the lines of the quantum feedback theory developed by Wiseman and Milburn, which provides us with cooling times and final temperatures as a function of feedback gain and various system parameters.
V. Steixner; P. Rabl; P. Zoller
A dynamical model for longitudinal wave functions in light-front holographic QCD
We construct a Schrodinger-like equation for the longitudinal wave function of a meson in the valence qq-bar sector, based on the 't Hooft model for large-N two-dimensional QCD, and combine this with the usual transverse equation from light-front holographic QCD, to obtain a model for mesons with massive quarks. The computed wave functions are compared with the wave function ansatz of Brodsky and De Teramond and used to compute decay constants and parton distribution functions. The basis functions used to solve the longitudinal equation may be useful for more general calculations of meson states in QCD.
S. S. Chabysheva; J. R. Hiller
Interferometric adaptive optics for high power laser pointing, wave-front control and phasing
Implementing the capability to perform fast ignition experiments, as well as, radiography experiments on the National Ignition Facility (NIF) places stringent requirements on the control of each of the beam's pointing and overall wavefront quality. One quad of the NIF beams, 4 beam pairs, will be utilized for these experiments and hydrodynamic and particle-in-cell simulations indicate that for the fast ignition experiments, these beams will be required to deliver 50% (4.0 kJ) of their total energy (7.96 kJ) within a 40 {micro}m diameter spot at the end of a fast ignition cone target. This requirement implies a stringent pointing and overall phase conjugation error budget on the adaptive optics system used to correct these beam lines. The overall encircled energy requirement is more readily met by phasing of the beams in pairs but still requires high Strehl ratios, Sr, and rms tip/tilt errors of approximately one {micro}rad. To accomplish this task we have designed an interferometric adaptive optics system capable of beam pointing, high Strehl ratio and beam phasing with a single pixilated MEMS deformable mirror and interferometric wave-front sensor. We present the design of a testbed used to evaluate the performance of this wave-front sensor below along with simulations of its expected performance level.
Baker, K L; Stappaerts, E A; Homoelle, D C; Henesian, M A; Bliss, E S; Siders, C W; Barty, C J
Status and specifications of a Project X front-end accelerator test facility at Fermilab
This paper describes the construction and operational status of an accelerator test facility for Project X. The purpose of this facility is for Project X component development activities that benefit from beam tests and any development activities that require 325 MHz or 650 MHz RF power. It presently includes an H- beam line, a 325 MHz superconducting cavity test facility, a 325 MHz (pulsed) RF power source, and a 650 MHz (CW) RF power source. The paper also discusses some specific Project X components that will be tested in the facility. Fermilab's future involves new facilities to advance the intensity frontier. In the early 2000's, the vision was a pulsed, superconducting, 8 GeV linac capable of injecting directly into the Fermilab Main Injector. Prototyping the front-end of such a machine started in 2005 under a program named the High Intensity Neutrino Source (HINS). While the HINS test facility was being constructed, the concept of a new, more versatile accelerator for the intensity frontier, now called Project X, was forming. This accelerator comprises a 3 GeV CW superconducting linac with an associated experimental program, followed by a pulsed 8 GeV superconducting linac to feed the Main Injector synchrotron. The CW Project X design is now the model for Fermilab's future intensity frontier program. Although CW operation is incompatible with the original HINS front-end design, the installation remains useful for development and testing many Project X components.
Steimel, J.; Webber, R.; Madrak, R.; Wildman, D.; Pasquinelli, R.; Evans-Peoples, E.; /Fermilab
The RHIC control system architecture follows the familiar ''standard model''. LINUX workstations are used as operator consoles. Front-end computers are distributed around the accelerator, close to equipment being controlled or monitored. These computers are generally based on VMEbus CPU modules running the VxWorks operating system. I/O is typically performed via the VMEbus, or via PMC daughter cards (via an internal PCI bus), or via on-board I/O interfaces (Ethernet or serial). Advances in FPGA size and sophistication now permit running virtual processor ''cores'' within the FPGA logic, including ''cores'' with advanced features such as memory management. Such systems offer certain advantages over traditional VMEbus Front-end computers. Advantages include tighter coupling with FPGA logic, and therefore higher I/O bandwidth, and flexibility in packaging, possibly resulting in a lower noise environment and/or lower cost. This paper presents the experience acquired while porting the RHIC control system to a PowerPC 405 core within a Xilinx FPGA for use in low-level RF control.
Low temperature front surface passivation of interdigitated back contact silicon heterojunction solar cell
The interdigitated back contact silicon heterojunction (IBC-SHJ) solar cell requires a low temperature front surface passivation/anti-reflection structure. Conventional silicon surface passivation using SiO2 or a-SiNx is performed at temperature higher than 400�C, which is not suitable for the IBC-SHJ cell. In this paper, we propose a PECVD a-Si:H/a-SiNx:H/a-SiC:H stack structure to passivate the front surface of crystalline silicon at low temperature. The optical properties and passivation quality of this structure are characterized and solar cells using this structure are fabricated. With 2 nm a-Si:H layer, the stack structure exhibits stable passivation with effective minority carrier lifetime higher than 2 ms, and compatible with IBC-SHJ solar cell processing. A critical advantage of this structure is that the SiC allows it to be HF resistant, thus it can be deposited as the first step in the process. This protects the a-Si/c-Si interface and maintains a low surface recombination velocity.
Shu, Brent; Das, Ujjwal; Jani, Omkar; Hegedus, Steve; Birkmire, Robert
Novel Approach for Selective Emitter Formation and Front Side Metallization of Crystalline Silicon Solar Cells
In this project we will explore the possibility of forming the front side metallization and selective emitter layer for the crystalline silicon solar cells through using selective laser ablation to create contact openings on the front surface and a screen printer to make connections with conductive paste. Using this novel approach we expect to reduce the specific contact resistance of the silver gridlines by about one order of magnitude compared to the state-of-art industrial crystalline silicon solar cells to below 1 m??cm2, and use lightly doped n+ emitter layer with sheet resistance of not smaller than 100 ?/?. This represents an enabling improvement on crystalline silicon solar cell performance and can increase the absolute efficiency of the solar cell by about 1%. In this scientific report we first present our result on the selective laser ablation of the nitride layer to make contact openings. Then we report our work on the solar cell fabrication by using the laser ablated contact openings with self-doping paste. Through various electrical property characterization and SIMS analysis, the factors limiting the cell performance have been discussed. While through this proof-of-concept project we could not reach the target on cell efficiency improvement, the process to fabricate 125mm full-sized silicon solar cells using laser ablation and self-doping paste has been developed, and a much better understanding of technical challenges has been achieved. Future direction to realize the potential of the new technology has been clearly defined.
Baomin Xu
An FPGA-based motherboard with an embedded hardware processor is used to implement a portable test- bench for the full certification of Tile Calorimeter front-end electronics in the ATLAS experiment at CERN. This upgrade will also allow testing future versions of the TileCal read-out electronics as well. Because of its lightness the new facility is highly portable, allowing on-detector validation using sophisticated algorithms. The new system comprises a front-end GUI running on an external portable computer which controls the motherboard. It also includes several dedicated daughter-boards that exercise the different specialized functionalities of the system. Apart from being used to evaluate different technologies for the future upgrades, it will be used to certify the consolidation of the electronics by identifying low frequency failures. The results of the tests presented here show that new system is well suited for the 2013 ATLAS Long Shutdown. We discuss all requirements necessary to give full confidence...
Kim, HY; The ATLAS collaboration; Carrio, F; Moreno, P; Masike, T; Reed, R; Sandrock, C; Schettino, V; Shalyugin, A; Solans, C; Souza, J; Suter, R; Usai, G; Valero, A
Wave front-ray synthesis for solving the multidimensional quantum Hamilton-Jacobi equation
A Cauchy initial-value approach to the complex-valued quantum Hamilton-Jacobi equation (QHJE) is investigated for multidimensional systems. In this approach, ray segments foliate configuration space which is laminated by surfaces of constant action. The QHJE incorporates all quantum effects through a term involving the divergence of the quantum momentum function (QMF). The divergence term may be expressed as a sum of two terms, one involving displacement along the ray and the other incorporating the local curvature of the action surface. It is shown that curvature of the wave front may be computed from coefficients of the first and second fundamental forms from differential geometry that are associated with the surface. Using the expression for the divergence, the QHJE becomes a Riccati-type ordinary differential equation (ODE) for the complex-valued QMF, which is parametrized by the arc length along the ray. In order to integrate over possible singularities in the QMF, a stable and accurate Moebius propagator is introduced. This method is then used to evolve rays and wave fronts for four systems in two and three dimensions. From the QMF along each ray, the wave function can be easily computed. Computational difficulties that may arise are described and some ways to circumvent them are presented.
Wyatt, Robert E.; Chou, Chia-Chun [Institute for Theoretical Chemistry and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States)
Direct numerical simulation of ignition front propagation in a constant volume with temperature inhomogeneities. I. Fundamental analysis and diagnostics
The influence of thermal stratification on autoignition at constant volume and high pressure is studied by direct numerical simulation (DNS) with detailed hydrogen/air chemistry with a view to providing better understanding and modeling of combustion processes in homogeneous charge compression-ignition engines. Numerical diagnostics are developed to analyze the mode of combustion and the dependence of overall ignition progress on initial mixture conditions. The roles of dissipation of heat and mass are divided conceptually into transport within ignition fronts and passive scalar dissipation, which modifies the statistics of the preignition temperature field. Transport within ignition fronts is analyzed by monitoring the propagation speed of ignition fronts using the displacement speed of a scalar that tracks the location of maximum heat release rate. The prevalence of deflagrative versus spontaneous ignition front propagation is found to depend on the local temperature gradient, and may be identified by the ratio of the instantaneous front speed to the laminar deflagration speed. The significance of passive scalar mixing is examined using a mixing timescale based on enthalpy fluctuations. Finally, the predictions of the multizone modeling strategy are compared with the DNS, and the results are explained using the diagnostics developed. (author)
Chen, Jacqueline H.; Hawkes, Evatt R.; Sankaran, Ramanan [Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, P.O. Box 969 MS 9051, Livermore, CA 94551-0969 (United States); Mason, Scott D. [Lockheed Martin Corporation, Sunnyvale, CA 94089 (United States); Im, Hong G. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)
Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation
We analyze the dynamical expansion of the HII region and outer photodissociation region (PDR) around a massive star by solving the UV and FUV radiation transfer and the thermal and chemical processes in a time-dependent hydrodynamics code. We focus on the physical structure of the shell swept up by the shock front (SF) preceding the ionization front (IF). After the IF reaches the initial Stromgren radius, the SF emerges in front of the IF and the geometrically thin shell bounded with the IF and the SF is formed. The gas density inside the shell is about 10-100 times as high as the ambient gas density. Initially the dissociation fronts expands faster than IF and the PDR is formed outside the HII region. Thereafter the IF and SF gradually overtakes the proceeding dissociation fronts (DFs), and eventually DFs are taken in the shell. The chemical composition within the shell is initially atomic, but hydrogen and carbon monoxide molecules are gradually formed. This is partly because the IF and SF overtake DFs and SF enters the molecular region, and partly because the reformation timescales of the molecules become shorter than the dynamical timescale. The gas shell becomes dominated by the molecular gas by the time of gravitational fragmentation, which agrees with some recent observations. A simple estimation of star formation rate in the shell can provide a significant star formation rate in our galaxy.
Takashi Hosokawa; Shu-ichiro Inutsuka
A Vehicle-to-Vehicle Communication Protocol for Cooperative Collision Warning
safer than B due to the following two reasons: � Line-of-sight limitation of brake light: Typically by Vodafone-U.S. Foundation Graduate Fellowship. and � , travel in the same lane. When � suddenly brakes, a driver can only see the brake light from the vehicle di- rectly in front1 . Thus, very likely vehicle
Liu, Jie
Mon. Not. R. Astron. Soc. 320, 131138 (2001) Discs and the 10-mm silicate spectra of young stellar objects with non-
Mon. Not. R. Astron. Soc. 320, 131±138 (2001) Discs and the 10-mm silicate spectra of young stellar and Taurus-Elias 7 (Haro6-10, GV Tau) is distinguished from foreground silicate absorption using a simple that of Elias 7 is optically thick. We suggest that HL Tau's optically thin component arises from silicate dust
Bowey, Janet
Scour of simulated Gulf Coast sand beaches due to wave action in front of sea walls and dune barriers
for the degree of MASTER OF SCIENCE May 1971 Ma)or Sub)ect: Civil Engineering SCOUR OF SIM(JLATED GULF COAST SAND BEACHES DUE TO WAVE ACTION IN FRONT OF SEA WALLS AND DUNE BARRIERS Q m Q F z A Thesis z m Q C by CHARLES BURGESS CHESNUTT L' m ) m... angle 53 LIST OF FIGURES (CONTINUED) Figure Page 15 Scour depth at the sea wall versus beach slope for constant wave steepness and varying sea wall angle 54 INTRODUCTION The problem of scour in front of sea walls has plagued coastal engineers...
Chesnutt, Charles Burgess
A 200-MHz fully-differential CMOS front-end with an on-chip inductor for magnetic resonance imaging
A 200-MHZ FULLY-DIFFERENTIAL CMOS FRONT-END WITH AN ON-CHIP INDUCTOR FOR MAGNETIC RESONANCE IMAGING A Thesis by JULIO ENRIQUE AYALA II Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 2005 Major Subject: Electrical Engineering A 200-MHZ FULLY-DIFFERENTIAL CMOS FRONT-END WITH AN ON-CHIP INDUCTOR FOR MAGNETIC RESONANCE IMAGING A Thesis by JULIO ENRIQUE AYALA II Submitted to the Office of Graduate...
Ayala, Julio Enqrique, II
Generalizing the flash technique in the front-face configuration to measure the thermal diffusivity of semitransparent solids
In this work, we have extended the front-face flash method to retrieve simultaneously the thermal diffusivity and the optical absorption coefficient of semitransparent plates. A complete theoretical model that allows calculating the front surface temperature rise of the sample has been developed. It takes into consideration additional effects, such as multiple reflections of the heating light beam inside the sample, heat losses by convection and radiation, transparency of the sample to infrared wavelengths, and heating pulse duration. Measurements performed on calibrated solids, covering a wide range of absorption coefficients (from transparent to opaque) and thermal diffusivities, validate the proposed method.
Pech-May, Nelson Wilbur [Departamento de F�sica Aplicada I, Escuela T�cnica Superior de Ingenier�a, Universidad del Pa�s Vasco UPV/EHU, Alameda Urquijo s/n, 48013 Bilbao (Spain); Department of Applied Physics, CINVESTAV Unidad M�rida, carretera Antigua a Progreso km6, A.P. 73 Cordemex, M�rida Yucat�n 97310, M�xico (Mexico); Mendioroz, Arantza; Salazar, Agust�n, E-mail: email@example.com [Departamento de F�sica Aplicada I, Escuela T�cnica Superior de Ingenier�a, Universidad del Pa�s Vasco UPV/EHU, Alameda Urquijo s/n, 48013 Bilbao (Spain)
PDP-11 front-end for a VAX-11/780
An unpublicized feature of the VAX-11/780 is the provision for attaching a PDP-11 to the VAX UNIBUS Adapter. Doing this can give significantly improved I/O performance for applications which are limited by overhead in the VAX I/O driver rather than by the transfer speed of the UNIBUS itself. Such a system was implemented by using a PDP-11/04 as a front-end to a CAMAC data acquisition system. Both the PDP and the VAX have full access to the UNIBUS. That portion of the PDP address space that does not have UNIBUS memory can be mapped to buffers in the VAX memory; this approach allows the PDP to access VAX memory and to initiate DMA transfers directly to the VAX. The VAX also has full access to the PDP memory; a convenient means for developing and downloading the PDP software is thus provided. 5 figures.
Browne, M.J.; Granieri, C.; Sherden, D.J.; Weaver, L.J.
Review of input stages used in front end electronics for particle detectors
In this paper we present noise analysis of the input stages most commonly used in front end electronics for particle detectors. Analysis shows the calculation of the input referenced noise related to the active devices. It identifies the type, parallel or series, of the equivalent noise sources related to the input transistors, which is the important input for the further choice of the signal processing method. Moreover we calculate the input impedance of amplifiers employed in applications where the particle detector is connected to readout electronics by means of transmission line. We present schematics, small signal models,a complete set of equations, and results of the major steps of calculations for all discussed circuits.
Kaplon, J
Evaluation of a front-end ASIC for the readout of PMTs in large dynamic range
The Large High Altitude Air Shower Observatory (LHAASO) project has been proposed for the survey and study of cosmic rays. In the LHAASO project, the Water Cherenkov Detector Array (WCDA) is one of major detectors for searching gamma ray sources. A Charge-to-Time Convertor (QTC) ASIC (Application Specification Integrated Circuit) fabricated in Global Foundry 0.35 {\\mu}m CMOS technology, has been developed for readout of Photomultiplier Tubes (PMTs) in the WCDA. This paper focuses on the evaluation of this front-end readout ASIC performance. Test results indicate that the time resolution is better than 400 ps and the charge resolution is better than 1% with large input signals and remains better than 15% @ 1 Photo Electron (P.E.), both beyond the application requirement. Moreover, this ASIC has a weak ambient temperature dependence, low input rate dependence and high channel-to-channel isolation.
Wu, Weihao; Liang, Yu; Yu, Li; Liu, Jianfeng; Liu, Shubin; An, Qi
Weihao Wu; Lei Zhao; Yu Liang; Li Yu; Jianfeng Liu; Shubin Liu; Qi An
Pauli-Villars regularization of field theories on the light front
Four-dimensional quantum field theories generally require regularization to be well defined. This can be done in various ways, but here we focus on Pauli-Villars (PV) regularization and apply it to nonperturbative calculations of bound states. The philosophy is to introduce enough PV fields to the Lagrangian to regulate the theory perturbatively, including preservation of symmetries, and assume that this is sufficient for the nonperturbative case. The numerical methods usually necessary for nonperturbative bound-state problems are then applied to a finite theory that has the original symmetries. The bound-state problem is formulated as a mass eigenvalue problem in terms of the light-front Hamiltonian. Applications to quantum electrodynamics are discussed.
Hiller, John R. [Department of Physics, University of Minnesota-Duluth, Duluth, Minnesota 55812 (United States)
Gauge/Gravity Duality and Hadron Physics at the Light-Front
We discuss some remarkable features of the light-front holographic mapping of classical gravity in anti-de Sitter space modified by a confining dilaton background. In particular, we show that a positive-sign dilaton solution exp(+{kappa}{sup 2}z{sup 2}) has better chances to describe the correct hadronic phenomenology than the negative solution exp(-{kappa}{sup 2}z{sup 2}) extensively studied in the literature. We also show that the use of twist-scaling dimensions, instead of canonical dimensions, is required to give a good description of the spectrum and form factors of hadrons. Another key element is the explicit connection of AdS modes of total angular momentum J with the internal structure of hadrons and the proper identification of the orbital angular momentum of the constituents.
Teramond, Guy F. de [Universidad de Costa Rica, San Jose (Costa Rica); Brodsky, Stanley J. [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309, USA and CP3-Origins, University of Southern Denmark, Odense, 5230 M (Denmark)
Design and construction of the front-end electronics data acquisition for the SLD CRID
This paper describes the front-end electronics for the Cherenkov Ring Imaging Detector (CRID) of the SLD at the Stanford Linear Accelerator Center. The design philosophy and implementation are discussed with emphasis on the low-noise hybrid amplifiers, signal processing and data acquisition electronics. The system receives signals from a highly efficient single-photo electron detector. These signals are shaped and amplified before being stored in an analog memory and processed by a digitizing system. The data from several ADCs are multiplexed and transmitted via fiber optics to the SLD FASTBUS system. The authors highlight the technologies used, as well as the space, power dissipation, and environmental constraints imposed on the system.
Hoeflich, J.; McShurley, D.; Marshall, D.; Oxoby, G.; Shapiro, S.; Stiles, P. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)); Spencer, E. (California Univ., Santa Cruz, CA (United States). Inst. for Particle Physics)
Local stress-induced effects on AlGaAs/AlOx oxidation front shape
The lateral oxidation of thick AlGaAs layers (>500?nm) is studied. An uncommon shape of the oxide tip is evidenced and attributed to the embedded stress distribution, inherent to the oxidation reaction. Experimental and numerical studies of the internal strain in oxidized Al{sub x}Ga{sub 1?x}As/GaAs structures were carried out by dark-field electron holography and finite element methods. A mapping of the strain distribution around the AlGaAs/oxide interface demonstrates the main role of internal stress on the shaping of the oxide front. These results demonstrate the high relevance of strain in oxide-confined III-V devices, in particular, with over-500-nm thick AlOx confinement layers.
Chouchane, F.; Almuneau, G., E-mail: email@example.com; Arnoult, A.; Lacoste, G.; Fontaine, C. [CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse (France); Univ de Toulouse, UPS, LAAS, F-31400 Toulouse (France); Cherkashin, N. [Univ de Toulouse, UPS, LAAS, F-31400 Toulouse (France); CNRS, CEMES, 29 Rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France)
GYROSURFING ACCELERATION OF IONS IN FRONT OF EARTH's QUASI-PARALLEL BOW SHOCK
It is well known that shocks in space plasmas can accelerate particles to high energies. However, many details of the shock acceleration mechanism are still unknown. A critical element of shock acceleration is the injection problem; i.e., the presence of the so called seed particle population that is needed for the acceleration to work efficiently. In our case study, we present for the first time observational evidence of gyroresonant surfing acceleration in front of Earth's quasi-parallel bow shock resulting in the appearance of the long-suspected seed particle population. For our analysis, we use simultaneous multi-spacecraft measurements provided by the Cluster spacecraft ion (CIS), magnetic (FGM), and electric field and wave instrument (EFW) during a time period of large inter-spacecraft separation distance. The spacecraft were moving toward the bow shock and were situated in the foreshock region. The results show that the gyroresonance surfing acceleration takes place as a consequence of interaction between circularly polarized monochromatic (or quasi-monochromatic) transversal electromagnetic plasma waves and short large amplitude magnetic structures (SLAMSs). The magnetic mirror force of the SLAMS provides the resonant conditions for the ions trapped by the waves and results in the acceleration of ions. Since wave packets with circular polarization and different kinds of magnetic structures are very commonly observed in front of Earth's quasi-parallel bow shock, the gyroresonant surfing acceleration proves to be an important particle injection mechanism. We also show that seed ions are accelerated directly from the solar wind ion population.
Kis, Arpad; Lemperger, Istvan; Wesztergom, Viktor [Research Centre for Astronomy and Earth Sciences, Geodetic and Geophysical Institute, Sopron (Hungary); Agapitov, Oleksiy; Krasnoselskikh, Vladimir [LPC2E/CNRS, F-45071 Orleans (France); Khotyaintsev, Yuri V. [Swedish Institute of Space Physics, SE- 751 21 Uppsala (Sweden); Dandouras, Iannis, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [CESR, F-31028 Toulouse (France)
Scintillation counter and wire chamber front end modules for high energy physics experiments
This document describes two front-end modules developed for the proposed MIPP upgrade (P-960) experiment at Fermilab. The scintillation counter module was developed for the Plastic Ball detector time and charge measurements. The module has eight LEMO 00 input connectors terminated with 50 ohms and accepts negative photomultiplier signals in the range 0.25...1000 pC with the maximum input voltage of 4.0 V. Each input has a passive splitter with integration and differentiation times of {approx}20 ns. The integrated portion of the signal is digitized at 26.55 MHz by Analog Devices AD9229 12-bit pipelined 4-channel ADC. The differentiated signal is discriminated for time measurement and sent to one of the four TMC304 inputs. The 4-channel TMC304 chip allows high precision time measurement of rising and falling edges with {approx}100 ps resolution and has internal digital pipeline. The ADC data is also pipelined which allows deadtime-less operation with trigger decision times of {approx}4 {micro}s. The wire chamber module was developed for MIPP EMCal detector charge measurements. The 32-channel digitizer accepts differential analog signals from four 8-channel integrating wire amplifiers. The connection between wire amplifier and digitizer is provided via 26-wire twist-n-flat cable. The wire amplifier integrates input wire current and has sensitivity of 275 mV/pC and the noise level of {approx}0.013 pC. The digitizer uses the same 12-bit AD9229 ADC chip as the scintillator counter module. The wire amplifier has a built-in test pulser with a mask register to provide testing of the individual channels. Both modules are implemented as a 6Ux220 mm VME size board with 48-pin power connector. A custom europack (VME) 21-slot crate is developed for housing these front-end modules.
Baldin, Boris; DalMonte, Lou; /Fermilab
Measures of the environmental footprint of the front end of the nuclear fuel cycle
Previous estimates of environmental impacts associated with the front end of the nuclear fuel cycle (FEFC) have focused primarily on energy consumption and CO2 emissions. Results have varied widely. This work builds upon reports from operating facilities and other primary data sources to build a database of front end environmental impacts. This work also addresses land transformation and water withdrawals associated with the processes of the FEFC. These processes include uranium extraction, conversion, enrichment, fuel fabrication, depleted uranium disposition, and transportation. To allow summing the impacts across processes, all impacts were normalized per tonne of natural uranium mined as well as per MWh(e) of electricity produced, a more conventional unit for measuring environmental impacts that facilitates comparison with other studies. This conversion was based on mass balances and process efficiencies associated with the current once-through LWR fuel cycle. Total energy input is calculated at 8.7 x 10- 3 GJ(e)/MWh(e) of electricity and 5.9 x 10- 3 GJ(t)/MWh(e) of thermal energy. It is dominated by the energy required for uranium extraction, conversion to fluoride compound for subsequent enrichment, and enrichment. An estimate of the carbon footprint is made from the direct energy consumption at 1.7 kg CO2/MWh(e). Water use is likewise dominated by requirements of uranium extraction, totaling 154 L/MWh(e). Land use is calculated at 8 x 10- 3 m2/MWh(e), over 90% of which is due to uranium extraction. Quantified impacts are limited to those resulting from activities performed within the FEFC process facilities (i.e. within the plant gates). Energy embodied in material inputs such as process chemicals and fuel cladding is identified but not explicitly quantified in this study. Inclusion of indirect energy associated with embodied energy as well as construction and decommissioning of facilities could increase the FEFC energy intensity estimate by a factor of up to 2.
E. Schneider; B. Carlsen; E. Tavrides; C. van der Hoeven; U. Phathanapirom
Cast Stone Oxidation Front Evaluation: Preliminary Results For Samples Exposed To Moist Air
The rate of oxidation is important to the long-term performance of reducing salt waste forms because the solubility of some contaminants, e.g., technetium, is a function of oxidation state. TcO{sub 4}{sup ?} in the salt solution is reduced to Tc(IV) and has been shown to react with ingredients in the waste form to precipitate low solubility sulfide and/or oxide phases. Upon exposure to oxygen, the compounds containing Tc(IV) oxidize to the pertechnetate ion, Tc(VII)O{sub 4}{sup ?}, which is very soluble. Consequently the rate of technetium oxidation front advancement into a monolith and the technetium leaching profile as a function of depth from an exposed surface are important to waste form performance and ground water concentration predictions. An approach for measuring contaminant oxidation rate (effective contaminant specific oxidation rate) based on leaching of select contaminants of concern is described in this report. In addition, the relationship between reduction capacity and contaminant oxidation is addressed. Chromate (Cr(VI) was used as a non-radioactive surrogate for pertechnetate, Tc(VII), in Cast Stone samples prepared with 5 M Simulant. Cast Stone spiked with pertechnetate was also prepared and tested. Depth discrete subsamples spiked with Cr were cut from Cast Stone exposed to Savannah River Site (SRS) outdoor ambient temperature fluctuations and moist air. Depth discrete subsamples spiked with Tc-99 were cut from Cast Stone exposed to laboratory ambient temperature fluctuations and moist air. Similar conditions are expected to be encountered in the Cast Stone curing container. The leachability of Cr and Tc-99 and the reduction capacities, measured by the Angus-Glasser method, were determined for each subsample as a function of depth from the exposed surface. The results obtained to date were focused on continued method development and are preliminary and apply to the sample composition and curing / exposure conditions described in this report. The Cr oxidation front (depth to which soluble Cr was detected) for the Cast Stone sample exposed for 68 days to ambient outdoor temperatures and humid air (total age of sample was 131 days) was determined to be about 35 mm below the top sample surface exposed. The Tc oxidation front, depth at which Tc was insoluble, was not determined. Interpretation of the results indicates that the oxidation front is at least 38 mm below the exposed surface. The sample used for this measurement was exposed to ambient laboratory conditions and humid air for 50 days. The total age of the sample was 98 days. Technetium appears to be more easily oxidized than Cr in the Cast Stone matrix. The oxidized forms of Tc and Cr are soluble and therefore leachable. Longer exposure times are required for both the Cr and Tc spiked samples to better interpret the rate of oxidation. Tc spiked subsamples need to be taken further from the exposed surface to better define and interpret the leachable Tc profile. Finally Tc(VII) reduction to Tc(IV) appears to occur relatively fast. Results demonstrated that about 95 percent of the Tc(VII) was reduced to Tc(IV) during the setting and very early stage setting for a Cast Stone sample cured 10 days. Additional testing at longer curing times is required to determine whether additional time is required to reduce 100 % of the Tc(VII) in Cast Stone or whether the Tc loading exceeded the ability of the waste form to reduce 100 % of the Tc(VII). Additional testing is required for samples cured for longer times. Depth discrete subsampling in a nitrogen glove box is also required to determine whether the 5 percent Tc extracted from the subsamples was the result of the sampling process which took place in air. Reduction capacity measurements (per the Angus-Glasser method) performed on depth discrete samples could not be correlated with the amount of chromium or technetium leached from the depth discrete subsamples or with the oxidation front inferred from soluble chromium and technetium (i.e., effective Cr and Tc oxidation fronts). Residual reduction capacity
Langton, C. A.; Almond, P. M.
An Eta-model output study of frontogenesis conditions favoring development of a troposphere-spanning front
the importance of a cooperative relationship between the frontogenesis terms noted above. Upstream of the 500 mb trough, the tilting process of differential vertical motion ants in a positive sense and results in the formation of an upper-tropospheric front...
Stewart, Jeffrey Paul
Safety and Environment Considerations and Analysis Safety and environmental issues are being considered up front in the APEX project as
Safety and Environment Considerations and Analysis Safety and environmental issues are being considered up front in the APEX project as designs evolve so that the goal of safety and environmental attractiveness is realized. Designing safety into the concepts as was done in the ITER project [1] results
California at Los Angeles, University of
rencontre du non-lineaire 2009 101 Effets d'un forcage spatial sur la dynamique des fronts
. Haudin1 , R. G. El´ias2 , M. G. Clerc2 ,, U. Bortolozzo1 , & S. Residori1 1 Institut Non Lin´eaire de´eris´ee par une propagation du front visant `a diminuer la taille du domaine le moins stable ´energ
Gavilan, Marcel G. Clerc
Robust ASR front-end using spectral-based and discriminant features: experiments on the Aurora tasks
Robust ASR front-end using spectral-based and discriminant features: experiments on the Aurora was tested on the set of speech corpora used for the "Aurora" evaluation. Using the feature stream generated and server side ASR processing, a standartization initiative called "Aurora" was initiated within European
Dupont, Stéphane
ICPIG, July 15-20, 2007, Prague, Czech Republi Negative streamer fronts: comparison of particle and fluid models and
that propagates into non-ionized matter. Streamers are used in industrial applications such as ozone generation28th ICPIG, July 15-20, 2007, Prague, Czech Republi Negative streamer fronts: comparison be generated during early stages of the lighting event. Both questions require a fully kinetic description
Ebert, Ute
Temperature activated absorption during laser-induced damage: The evolution of laser-supported solid-state absorption fronts
Previously we have shown that the size of laser induced damage sites in both KDP and SiO{sub 2} is largely governed by the duration of the laser pulse which creates them. Here we present a model based on experiment and simulation that accounts for this behavior. Specifically, we show that solid-state laser-supported absorption fronts are generated during a damage event and that these fronts propagate at constant velocities for laser intensities up to 4 GW/cm{sup 2}. It is the constant absorption front velocity that leads to the dependence of laser damage site size on pulse duration. We show that these absorption fronts are driven principally by the temperature-activated deep sub band-gap optical absorptivity, free electron transport, and thermal diffusion in defect-free silica for temperatures up to 15,000K and pressures < 15GPa. In addition to the practical application of selecting an optimal laser for pre-initiation of large aperture optics, this work serves as a platform for understanding general laser-matter interactions in dielectrics under a variety of conditions.
Carr, C W; Bude, J D; Shen, N; Demange, P
Materials and Design 24 (2003) 6978 0261-3069/03/$ -see front matter 2002 Elsevier Science Ltd. All rights reserved.
operate near their limits of thermal cracking and melting erosion resistances during long-burst firing. Due to their high melting temperature (controls melting- erosion resistance), high hotMaterials and Design 24 (2003) 6978 0261-3069/03/$ - see front matter 2002 Elsevier Science Ltd
Grujicic, Mica
PHYSICAL REVIEW E 84, 036104 (2011) Average crack-front velocity during subcritical fracture propagation in a heterogeneous medium
PHYSICAL REVIEW E 84, 036104 (2011) Average crack-front velocity during subcritical fracture]. In consequence the slow kinetic crack propagation is usually referred to as subcritical crack growth or the subcritical regime. Statistical physics models suggest that this subcritical regime is governed by a thermally
Schmittbuhl, Jean
Effects of Ambient Velocity Shear on Nonlinear Internal Waves and Associated Mixing at the Columbia River Plume Front
distinct water masses: (a) source water at the lift-off point, and (b) the tidal, (c) re-circulating, and (d) far-field plumes [Horner-Devine et al, 2008]. The tidal plume is the water from the most recent front transitions from supercritical to subcritical conditions [Nash and Moum, 2005; Jay et al., 2008
January/February 2000 2000, Elsevier Science Inc., 1040-6190/00/$see front matter PII S1040-6190(99)00102-5 25 Health Effects of
January/February 2000 © 2000, Elsevier Science Inc., 1040-6190/00/$see front matter PII S1040-6190/00/$see front matter PII S1040-6190(99)00102-5 The Electricity Journal Paul Brodeur in The New Yorker
Illinois at Chicago, University of
October 2000 2000, Elsevier Science Inc., 1040-6190/00/$see front matter PII S1040-6190(00)00146-9 38 Flow-Based Transmission
October 2000 © 2000, Elsevier Science Inc., 1040-6190/00/$see front matter PII S1040 Inc., 1040-6190/00/$see front matter PII S1040-6190(00)00146-9 39 tralized spot or real-time market
Oren, Shmuel S.
Submitted to EUROSPEECH 2003, September 1-4, 2003 -Geneva, Switzerland Enhancement of Noisy Speech for Noise Robust Front-End and Speech
Submitted to EUROSPEECH 2003, September 1-4, 2003 - Geneva, Switzerland Enhancement of Noisy Speech enhancement method for noise ro- bust front-end and speech reconstruction at the back-end of Dis- tributed. 2. Noise robust front-end algorithm The speech enhancement methods in combination with feature
Wichmann, Felix
Journal of Statistical Physics, Vol. 90, Nos. 5/6, 1998 We study the nucleation and growth of flame fronts in slow combustion. This
fronts in slow combustion. This is modeled by a set of reaction-diffusion equations for the temperature: Nucleation; reaction-diffusion systems; flame fronts. Nucleation, Growth, and Scaling in Slow Combustion applied to understand some aspects of slow combustion. We use a phase-field model of two coupled reaction
Grant, Martin
Partial Solar Eclipse Watch Party More than 100 people joined us on Thursday, October 23 to watch as the Moon slipped in front of the Sun during
as the Moon slipped in front of the Sun during a partial solar eclipse. We had telescopes and cameras set up to safely view the Sun. Solar glasses were available for purchase in the ticket booth. News stations from that the total gravity force on Earth is increased during a total eclipse, when the Moon goes in front of the Sun
Huang, Haiying
Kinematics and thermodynamics across a propagating non-stoichiometric oxidation phase front in spent fuel grains
Spent fuel contains mixtures, alloy and compound, but are dominated by U and O except for some UO{sub 2} fuels with burnable poisons (gadolinia in BWR rods), the other elements evolve during reactor operation from neutron reaction and fission + fission decay events. Due to decay, chemical composition and activity of spent fuel will continue to evolve after removal from reactors. During the time interval with significant radioactivity levels relevant for a geological repository, it is important to develop models for potential chemical responses in spent fuel and potential degradation of repository. One such potential impact is the oxidation of spent fuel, which results in initial phase change of UO{sub 2} lattice to U{sub 4}O{sub 9} and the next phase change is probably to U{sub 3}O{sub 8} although it has not been observed yet below 200C. The U{sub 4}O{sub 9} lattice is nonstoichiometric with a O/U weight ratio at 2.4. Preliminary indications are that the UO{sub 2} has a O/U of 2. 4 at the time just before it transforms into the U{sub 4}O{sub 9} phase. In the oxygen weight gain versus time response, a plateau appears as the O/U approaches 2.4. Part of this plateau is due to geometrical effects of a U{sub 4}O{sub 9} phase change front propagating into UO{sub 2} grain volumes; however, this may indicate a metastable phase change delay kinetics or a diffusional related delay time until the oxygen density can satisfy stoichiometry and energy conditions for phase changes. Experimental data show a front of U{sub 4}O{sub 9} lattice structure propagating into grains of the UO{sub 2} lattice. To describe this spatially inhomogenous oxidation phase transition, as well as the expected U{sub 3}O{sub 8} phase transition from the U{sub 4}O{sub 9} lattice, lattice models are developed and spatially discontinuous kinematic and energetic expressions are derived. 9 refs.
Stout, R.B.; Kansa, E.J.; Wijesinghe, A.M.
CO mass upper limits in the Fomalhaut ring - the importance of NLTE excitation in debris discs and future prospects with ALMA
In recent years, gas has been observed in an increasing number of debris discs, though its nature remains to be determined. Here, we analyse CO molecular excitation in optically thin debris discs, and search ALMA Cycle-0 data for CO J=3-2 emission in the Fomalhaut ring. No significant line emission is observed; we set a 3-$\\sigma$ upper limit on the integrated line flux of 0.16 Jy km s$^{-1}$. We show a significant dependency of the CO excitation on the density of collisional partners $n$, on the gas kinetic temperature $T_k$ and on the ambient radiation field $J$, suggesting that assumptions widely used for protoplanetary discs (e.g. LTE) do not necessarily apply to their low density debris counterparts. When applied to the Fomalhaut ring, we consider a primordial origin scenario where H$_2$ dominates collisional excitation of CO, and a secondary origin scenario dominated by e$^-$ and H$_2$O. In either scenario, we obtain a strict upper limit on the CO mass of 4.9 $\\times$ 10$^{-4}$ M$_{\\oplus}$. This arises...
Matr�, L; Wyatt, M C; Dent, W R F
Electromagnetic energy conversion in downstream fronts from three dimensional kinetic reconnection
The electromagnetic energy equation is analyzed term by term in a 3D simulation of kinetic reconnection previously reported by Vapirev et al. [J. Geophys. Res.: Space Phys. 118, 1435 (2013)]. The evolution presents the usual 2D-like topological structures caused by an initial perturbation independent of the third dimension. However, downstream of the reconnection site, where the jetting plasma encounters the yet unperturbed pre-existing plasma, a downstream front is formed and made unstable by the strong density gradient and the unfavorable local acceleration field. The energy exchange between plasma and fields is most intense at the instability, reaching several pW/m{sup 3}, alternating between load (energy going from fields to particles) and generator (energy going from particles to fields) regions. Energy exchange is instead purely that of a load at the reconnection site itself in a region focused around the x-line and elongated along the separatrix surfaces. Poynting fluxes are generated at all energy exchange regions and travel away from the reconnection site transporting an energy signal of the order of about S?10{sup ?3}W/m{sup 2}.
Lapenta, Giovanni [Departement Wiskunde, KU Leuven, Universiteit Leuven (Belgium)] [Departement Wiskunde, KU Leuven, Universiteit Leuven (Belgium); Goldman, Martin; Newman, David [University of Colorado, Colorado 80309 (United States)] [University of Colorado, Colorado 80309 (United States); Markidis, Stefano [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden)] [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden); Divin, Andrey [Swedish Institute of Space Physics, Uppsala (Sweden)] [Swedish Institute of Space Physics, Uppsala (Sweden)
Nonperturbative QCD coupling and its {beta} function from light-front holography
The light-front holographic mapping of classical gravity in anti-de Sitter space, modified by a positive-sign dilaton background, leads to a nonperturbative effective coupling {alpha}{sub s}{sup AdS}(Q{sup 2}). It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx}1 GeV. The resulting {beta} function appears to capture the essential characteristics of the full {beta} function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on {alpha}{sub s}{sup AdS}(Q{sup 2}).
Brodsky, Stanley J.; Teramond, Guy F. de; Deur, Alexandre [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309 (United States); CP3-Origins, University of Southern Denmark, Odense, 5230 M (Denmark); Universidad de Costa Rica, San Jose (Costa Rica); Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)
CMS hadron calorimeter front-end upgrade for SLHC phase I
We present an upgrade plan for the CMS HCAL detector. The HCAL upgrade is required for the increased luminosity (3 * 10E34) of SLHC Phase I which is targeted for 2014. A key aspect of the HCAL upgrade is to add longitudinal segmentation to improve background rejection, energy resolution, and electron isolation at the L1 trigger. The increased segmentation is achieved by replacing the hybrid photodiodes (HPDs) with silicon PMTs (SIPMs). We plan to instrument each fiber of the calorimeter with an SIPM (103,000 total). We will then electrically sum outputs from selected SIPMs to form the longitudinal readout segments. In addition to having more longitudinal information, the upgrade plans include a new custom ADC with matched sensitivity and timing information. The increased data volume requires higher speed transmitters and the additional power dissipation for the readout electronics requires better thermal design, since much of the on-detector infrastructure (front-end electronics crates, cooling pipes, optical fiber plant, etc.) will remain the same. We will report on the preliminary designs for these upgraded systems, along with performance requirements and initial design studies.
Whitmore, Juliana; /Fermilab
Magnetic field effects on the thermonuclear combustion front of Chandrasekhar mass white dwarfs
The explosion of a type Ia supernova starts in a white dwarf as a laminar deflagration at the center of the star and soon several hydrodynamic instabilities, in particular, the Rayleigh-Taylor instability, begin to act. A cellular stationary combustion and a turbulent combustion regime are rapidly achieved by the flame and maintained up to the end of the so-called flamelet regime when the transition to detonation is believed to occur. The burning velocity at these regimes is well described by the fractal model of combustion. Using a semi-analytic approach, we describe the effect of magnetic fields on the fractalization of the front considering a white dwarf with a nearly dipolar magnetic field. We find an intrinsic asymmetry on the velocity field that may be maintained up to the free expansion phase of the remnant. Considering the strongest values inferred for a white dwarf's magnetic fields with strengths up to $10^{8}-10^{9}$ G at the surface and assuming that the field near the centre is roughly 10 times greater, asymmetries in the velocity field higher than $10-20 %$ are produced between the magnetic polar and the equatorial axis of the remnant which may be related to the asymmetries found from recent spectropolarimetric observations of very young SN Ia remnants. Dependence of the asymmetry with white dwarf composition is also analyzed.
Cristian R. Ghezzi; Elisabete M. de Gouveia Dal Pino; Jorge E. Horvath
TRENDS in Ecology & Evolution Vol.17 No.7 July 2002 http://tree.trends.com 0169-5347/02/$ see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S0169-5347(02)02506-5
front matter © 2002 Elsevier Science Ltd. All rights reserved. PII: S0169-5347(02)02506-5 301Research
Rosenberg, Noah
482 0169-5347/00/$ see front matter 2000 Elsevier Science Ltd. All rights reserved. PII: S0169-5347(00)01966-2 TREE vol. 15, no. 12 December 2000 hybrid incompatibility factors by the introgression
482 0169-5347/00/$ see front matter © 2000 Elsevier Science Ltd. All rights reserved. PII: S0169
Flaxman, Samuel M.
TRENDS in Biotechnology Vol.20 No.10 October 2002 http://tibtech.trends.com 0167-7799/02/$ see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S0167-7799(02)02047-4
front matter © 2002 Elsevier Science Ltd. All rights reserved. PII: S0167-7799(02)02047-4 437Review
Lebendiker, Mario
TRENDS in Biotechnology Vol.20 No.10 October 2002 http://tibtech.trends.com 0167-7799/02/$ see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S0167-7799(02)02032-2
front matter © 2002 Elsevier Science Ltd. All rights reserved. PII: S0167-7799(02)02032-2 407Research
Babu, M. Madan
The UK Infrared Telescope M33 monitoring project. IV. Variable red giant stars across the galactic disc
We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). The main aim was to identify stars in the very final stage of their evolution, and for which the luminosity is more directly related to the birth mass than the more numerous less-evolved giant stars that continue to increase in luminosity. In this fourth paper of the series, we present a search for variable red giant stars in an almost square degree region comprising most of the galaxy's disc, carried out with the WFCAM instrument in the K band. These data, taken during the period 2005--2007, were complemented by J- and H-band images. Photometry was obtained for 403 734 stars in this region; of these, 4643 stars were found to be variable, most of which are Asymptotic Giant Branch (AGB) stars. The variable stars are concentrated towards the centre of M33, more so than low-mass, less-evolved red giants. Our data were matched to optical catalogues of variable stars and ca...
Javadi, Atefeh; van Loon, Jacco Th; Khosroshahi, Habib; Golabatooni, Najmeh; Mirtorabi, Mohammad Taghi
Insights into gas heating and cooling in the disc of NGC 891 from Herschel far-infrared spectroscopy
We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in the nearby edge-on spiral galaxy, NGC 891: [CII] 158 $\\mu$m, [NII] 122, 205 $\\mu$m, [OI] 63, 145 $\\mu$m, and [OIII] 88 $\\mu$m. We find that the photoelectric heating efficiency of the gas, traced via the ([CII]+[OII]63)/$F_{\\mathrm{TIR}}$ ratio, varies from a mean of 3.5$\\times$10$^{-3}$ in the centre up to 8$\\times$10$^{-3}$ at increasing radial and vertical distances in the disc. A decrease in ([CII]+[OII]63)/$F_{\\mathrm{TIR}}$ but constant ([CII]+[OI]63)/$F_{\\mathrm{PAH}}$ with increasing FIR colour suggests that polycyclic aromatic hydrocarbons (PAHs) may become important for gas heating in the central regions. We compare the observed flux of the FIR cooling lines and total IR emission with the predicted flux from a PDR model to determine the gas density, surface temperature and the strength of the incident far-ultraviolet (FUV) radiation field, $G_{0}$. Resolving details on physical scales of ~0.6 kpc, a p...
Hughes, T M; Schirm, M R P; Parkin, T J; De Looze, I; Wilson, C D; Bendo, G J; Baes, M; Fritz, J; Boselli, A; Cooray, A; Cormier, D; Karczewski, O ?; Lebouteiller, V; Lu, N; Madden, S C; Spinoglio, L; Viaene, S
Satellite observations and numerical simulations of jet-front gravity waves over North America and North Atlantic Ocean
SATELLITE OBSERVATIONS AND NUMERICAL SIMULATIONS OF JET-FRONT GRAVITY WAVES OVER NORTH AMERICA AND NORTH ATLANTIC OCEAN A Thesis by MENG ZHANG Submitted to the Office of Graduate Studies of Texas A&M University in partial... OCEAN A Thesis by MENG ZHANG Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Fuqing Zhang Committee...
Zhang, Meng
The Electromagnetic Gauge Field Interpolation between the Instant Form and the Front Form of the Hamiltonian Dynamics
We present the electromagnetic gauge field interpolation between the instant form and the front form of the relativistic Hamiltonian dynamics and extend our interpolation of the scattering amplitude presented in the simple scalar field theory to the case of the electromagnetic gauge field theory with the scalar fermion fields known as the sQED theory. We find that the Coulomb gauge in the instant form dynamics (IFD) and the light-front gauge in the front form dynamics, or the light-front dynamics (LFD), are naturally linked by the unified general physical gauge that interpolates between these two forms of dynamics and derive the spin-1 polarization vector for the photon that can be generally applicable for any interpolation angle. Corresponding photon propagator for an arbitrary interpolation angle is found and examined in terms of the gauge field polarization and the interpolating time ordering. Using these results, we calculate the lowest-order scattering processes for an arbitrary interpolation angle in sQED. We provide an example of breaking the reflection symmetry under the longitudinal boost, $P^z \\leftrightarrow -P^z$, for the time-ordered scattering amplitude in any interpolating dynamics except the LFD and clarify the confusion in the prevailing notion of the equivalence between the infinite momentum frame (IMF) and the LFD. The particular correlation found in our previous analysis of the scattering amplitude in the simple scalar field theory, coined as the J-shaped correlation, between the total momentum of the system and the interpolation angle persists in the present analysis of the sQED scattering amplitude. We discuss the singular behavior of this correlation in conjunction with the zero-mode issue in the LFD.
Chueng-Ryong Ji; Ziyue Li; Alfredo Takashi Suzuki
Paper No. 150. Ray, Najm and McCoy 1 Ignition front structure in a methane-air jet.1
Paper No. 150. Ray, Najm and McCoy 1 Ignition front structure in a methane-air jet.1 J.Ray2 , H. N-premixed methane jet in coflow air using the GRImech1.2 chemical mechanism. Ignition is initiated in the jet mixing flame, as compared to a stoichiometric premixed flame. In this study we ignite a methane-air jet
Ray, Jaideep
Redesign and Reconstruction of the Equipment Protection Systems for the Upgrading Front Ends and Beamlines at BSRF
The BEPC(Beijing Electron-Positron Collider) is upgraded to be BEPCII, a two-ring Electron-Positron collider. Due to the construction of the BEPCII and upgrade of the existing front ends and beamlines, all the existing EPSs(Equipment Protection Systems) have to be redesigned and reconstructed at BSRF. All the redesigned EPSs for the upgrading front ends and beamlines are a PLC- and SCADA-based equipment protection and control and monitoring system. The EPSs are used to protect BEPCII two storage rings vacuum against vacuum failures in a beamline, as well as to protect the front-end and beamline components from being damaged by synchrotron radiation. For the high-power wiggler beam lines, a fast movable mask is used to protect the blade of a fast-closing valve from damage when the fast-closing valve is triggered to close, which does not need to dump the electron beam running in BEPCII outer ring. In addition, all redesigned PLC- based EPSs are used to communicate with the same centralized monitoring computer to monitor a variety of parameters from all PLC- based EPS systems. The monitoring computer runs the SCADA (Supervisory Control And Data Acquisition) software with its own web server. Graphical HMI interfaces are used to display a few overall views of all front-end equipment operation status and the further detailed information for each EPS in a different pop-up window. On the web services, the SCADA-based centralized monitoring system provides a web browse function, etc. The design of the reconstructed systems is described in this paper.
Xiong Shenshou; Tan Yinglei; Wu Xuehui [Beijing Synchrotron Radiation Laboratory, Institute of High Energy Physics, P. O. Box 918, Branch 2-7, Beijing 100049 (China)
Discrete Symmetries on the Light Front and a General Relation Connecting Nucleon Electric Dipole and Anomalous Magnetic Moments
We consider the electric dipole form factor, F_3(q^2), as well as the Dirac and Pauli form factors, F_1(q^2) and F_2(q^2), of the nucleon in the light-front formalism. We derive an exact formula for F_3(q^2) to complement those known for F_1(q^2) and F_2(q^2). We derive the light-front representation of the discrete symmetry transformations and show that time-reversal- and parity-odd effects are captured by phases in the light-front wave functions. We thus determine that the contributions to F_2(q^2) and F_3(q^2), Fock state by Fock state, are related, independent of the fundamental mechanism through which CP violation is generated. Our relation is not specific to the nucleon, but, rather, is true of spin-1/2 systems in general, be they lepton or baryon. The empirical values of the anomalous magnetic moments, in concert with empirical bounds on the associated electric dipole moments, can better constrain theories of CP violation. In particular, we find that the neutron and proton electric dipole moments echo the isospin structure of the anomalous magnetic moments, kappa^n ~ - kappa^p.
S. J. Brodsky; S. Gardner; D. S. Hwang
Implications of Canada, snow, and white-fronted geese and Northern bobwhite as disease reservoirs for the Attwater's prairie-chicken
, 10 Canada (Branta canadensis), 24 snow (Chen caerulescens), and 22 white-fronted geese (Anser albifrons) were examined for endoparasites. Northern bobwhite (Colinus virginianus) (n = 62), the closest relative of Attwater's prairie...
Purvis, Jonny Ray
Surface and Coatings Technology 169170 (2003) 379383 0257-8972/03/$ -see front matter 2003 Elsevier Science B.V. All rights reserved.
Surface and Coatings Technology 169170 (2003) 379383 0257-8972/03/$ - see front matter 2003650 km) is rich in atomic oxygen. This highly reactive element impacts satellites at relative velocities
Open apex shaped charge-type explosive device having special disc means with slide surface thereon to influence movement of open apex shaped charge liner during collapse of same during detonation
An open apex shape charge explosive device is disclosed having an inner liner defining a truncated cone, an explosive charge surrounding the truncated inner liner, a primer charge, and a disc located between the inner liner and the primer charge for directing the detonation of the primer charge around the end edge of the disc means to the explosive materials surrounding the inner liner. The disc comprises a material having one or more of: a higher compressive strength, a higher hardness, and/or a higher density than the material comprising the inner liner, thereby enabling the disc to resist deformation until the liner collapses. The disc has a slide surface thereon on which the end edge of the inner liner slides inwardly toward the vertical axis of the device during detonation of the main explosive surrounding the inner liner, to thereby facilitate the inward collapse of the inner liner. In a preferred embodiment, the geometry of the slide surface is adjusted to further control the collapse or [beta] angle of the inner liner. 12 figures.
Murphy, M.J.
An open apex shape charge explosive device is disclosed having an inner liner defining a truncated cone, an explosive charge surrounding the truncated inner liner, a primer charge, and a disc located between the inner liner and the primer charge for directing the detonation of the primer charge around the end edge of the disc means to the explosive materials surrounding the inner liner. The disc comprises a material having one or more of: a higher compressive strength, a higher hardness, and/or a higher density than the material comprising the inner liner, thereby enabling the disc to resist deformation until the liner collapses. The disc has a slide surface thereon on which the end edge of the inner liner slides inwardly toward the vertical axis of the device during detonation of the main explosive surrounding the inner liner, to thereby facilitate the inward collapse of the inner liner. In a preferred embodiment, the geometry of the slide surface is adjusted to further control the collapse or .beta. angle of the inner liner.
Murphy, Michael J. (Livermore, CA)
The ATLAS Electromagnetic (EM) calorimeter (EMCAL) Front End Board (FEB) will be located in custom-designed enclosures solidly connected to the feedtroughs. It is a complex mixed signal board which includes the preamplifier, shaper, switched capacitor array analog memory unit (SCA), analog to digital conversion, serialization of the data and related control logic. It will be described in detail elsewhere in these proceedings. The electromagnetic interference (either pick-up from the on board digital activity, from power supply ripple or from external sources) which affects coherently large groups of channels (coherent noise) is of particular concern in calorimetry and it has been studied in detail.
Volume One Disc Two
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched Ferromagnetism inS-4500IIVasudhaSurface. | EMSLVisualizingwith
Effect of Front-Side Silver Metallization on Underlying n+-p Junction in Multicrystalline Silicon Solar Cells: Preprint
We report on the effect of front-side Ag metallization on the underlying n+-p junction of multicrystalline Si solar cells. The junction quality beneath the contacts was investigated by characterizing the uniformities of the electrostatic potential and doping concentration across the junction, using scanning Kelvin probe force microscopy and scanning capacitance microscopy. We investigated cells with a commercial Ag paste (DuPont PV159) and fired at furnace setting temperatures of 800 degrees, 840 degrees, and 930 degrees C, which results in actual cell temperatures ~100 degrees C lower than the setting temperature and the three cells being under-, optimal-, and over-fired. We found that the uniformity of the junction beneath the Ag contact was significantly degraded by the over-firing, whereas the junction retained good uniformity with the optimal- and under-fire temperatures. Further, Ag crystallites with widely distributed sizes from <100 nm to several ?m were found at the Ag/Si interface of the over-fired cell. Large crystallites were imaged as protrusions into Si deeper than the junction depth. However, the junction was not broken down; instead, it was reformed on the entire front of the crystallite/Si interface. We propose a mechanism of the junction-quality degradation, based on emitter Si melting at the temperature around the Ag-Si eutectic point during firing, and subsequent recrystallization with incorporation of impurities in the Ag paste and with formation of crystallographic defects during quenching.
Jiang, C. S.; Li, Z. G.; Moutinho, H. R.; Liang, L.; Ionkin, A.; Al-Jassim, M. M.
TRENDS in Cognitive Sciences Vol.5 No.12 December 2001 http://tics.trends.com 1364-6613/01/$ see front matter 2001 Elsevier Science Ltd.All rights reserved. PII: S1364-6613(00)01803-9
front matter © 2001 Elsevier Science Ltd.All rights reserved. PII: S1364-6613(00)01803-9 517Opinion Afew
Coulson, Seana
TRENDS in Biotechnology Vol.19 No.12 December 2001 http://tibtech.trends.com 0167-7799/01/$ see front matter 2001 Elsevier Science Ltd.All rights reserved. PII: S0167-7799(01)01813-3
front matter © 2001 Elsevier Science Ltd.All rights reserved. PII: S0167-7799(01)01813-3 482 Research
Gough, Julian
Comparison among Hamiltonian light-front formalisms at q+ = 0 and q+ 0: space-like elastic form factors of pseudoscalar and vector mesons
The electromagnetic elastic form factors of pseudoscalar and vector mesons are analyzed for space-like momentum transfers in terms of relativistic quark models based on the Hamiltonian light-front formalism elaborated in different reference frames (q+ 0 and q+ 0). As far as the one-body approximation for the electromagnetic current operator is concerned, it is shown that the predictions of the light-front approach at q+=0 should be preferred, particularly in case of light hadrons, because of: i) the relevant role played by the Z-graph at q+ 0, and ii) the appropriate elimination of spurious effects, related to the orientation of the null hyperplane where the light-front wave function is defined.
Silvano Simula
Considerations on the design of front-end electronics for silicon calorimetry for the SSC (Superconducting Super Collider)
Some considerations are described for the design of a silicon-based sampling calorimetry detector for the Superconducting Super Collider (SSC). The use of silicon as the detection medium allows fast, accurate, and fine-grained energy measurements -- but for optimal performance, the front-end electronics must be matched to the detector characteristics and have the speed required by the high SSC interaction rates. The relation between the signal-to-noise ratio of the calorimeter electronics and the charge collection time, the preamplifier power dissipation, detector capacitance and leakage, charge gain, and signal shaping and sampling was studied. The electrostatic transformer connection was analyzed and found to be unusable for a tightly arranged calorimeter because of stray capacitance effects. The method of deconvolutional sampling was developed as a means for pileup correction following synchronous sampling and analog storage. 3 refs., 6 figs.
Wintenberg, A.L.; Bauer, M.L.; Britton, C.L. Jr.; Kennedy, E.J.; Todd, R.A. (Oak Ridge National Lab., TN (USA)); Berridge, S.C.; Bugg, W.M. (Tennessee Univ., Knoxville, TN (USA))
Conjugation and transformation of the wave front by stimulated Brillouin scattering of vortex Laguerre - Gaussian laser modes
We study experimentally stimulated Brilluoin scattering (SBS) of vortex laser beams, namely, the LG{sub 1}{sup 1} and LG{sub 0}{sup 1} Laguerre -Gaussian modes. The wave front transformation is experimentally demonstrated in the case of SBS of the LG{sub 1}{sup 1} laser mode, directly focused into the SBS cell, when the fundamental Gaussian mode LG{sub 0}{sup 0} rather than the conjugate mode is selected from the Stokes beam. It is shown that optical vortices become phase conjugate by destroying the laser mode structure in the SBS cell. Phase conjugation (PC) of the LG{sub 0}{sup 1} and LG{sub 1}{sup 1} modes is obtained in the SBS mirror using a regular aberrator (microlens raster) in the system of laser beam focusing into the SBS cell.
Kopalkin, A V; Bogachev, V A; Dolgopolov, Yu V; Kochemasov, G G; Kulikov, S M; Maslov, N V; Starikov, F A; Sukharev, Stanislav A; Feoktistov, V V; Bagdasarov, V Kh; Denisov, N N; Malyutin, A A
Influence of the pattern shape on the photonic efficiency of front-side periodically patterned ultrathin crystalline silicon solar cells
Patterning the front side of an ultra-thin crystalline silicon (c Si) solar cell helps keeping the energy conversion efficiency high by compensating for the light absorption losses. A super-Gaussian mathematical expression was used in order to encompass a large variety of nanopattern shapes and to study their influence on the photonic performance. We prove that the enhancement in the maximum achievable photo-current is due to both impedance matching condition at short wavelengths and to the wave nature of light at longer wavelengths. We show that the optimal mathematical shape and parameters of the pattern depend on the c Si thickness. An optimal shape comes with a broad optimal parameter zone where fabricating errors would have much less influence on the efficiency. We prove that cylinders are not the best suited shape. To compare our model with a real slab, we fabricated a nanopatterned c Si slab via Nano Imprint Lithography.
Herman, Aline; Depauw, Valerie; Daif, Ounsi El; Deparis, Olivier
Design and construction of the front-end electronics data acquisition for the SLD CRID (Cherenkov Ring Imaging Detector)
We describe the front-end electronics for the Cherenkov Ring Imaging Detector (CRID) of the SLD at the Stanford Linear Accelerator Center. The design philosophy and implementation are discussed with emphasis on the low-noise hybrid amplifiers, signal processing and data acquisition electronics. The system receives signals from a highly efficient single-photo electron detector. These signals are shaped and amplified before being stored in an analog memory and processed by a digitizing system. The data from several ADCs are multiplexed and transmitted via fiber optics to the SLD FASTBUS system. We highlight the technologies used, as well as the space, power dissipation, and environmental constraints imposed on the system. 16 refs., 10 figs.
Hoeflich, J.; McShurley, D.; Marshall, D.; Oxoby, G.; Shapiro, S.; Stiles, P. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Spencer, E. (California Univ., Santa Cruz, CA (USA). Inst. for Particle Physics)
Isoperimetric inequalities for wave fronts and a generalization of Menzin's conjecture for bicycle monodromy on surfaces of constant curvature
We prove generalizations of the isoperimetric inequality for both spherical and hyperbolic wave fronts (i.e. piecewise smooth curves which may have cusps). We then discuss "bicycle curves" using the generalized isoperimetric inequalities. The euclidean model of a bicycle is a unit segment AB that can move so that it remains tangent to the trajectory of point A (the rear wheel is fixed on the bicycle frame). We extend this definition to a general Riemannian manifold, and concern ourselves in particular with bicycle curves in the hyperbolic plane H^2 and on the sphere S^2. We prove results along the lines of those proven by Levi and Tabachnikov and resolve both spherical and hyperbolic versions of Menzin's conjecture, which relates the area bounded by a curve to its associated monodromy map.
Howe, Sean; Zakharevich, Valentin
Mechanisms for plasma and reactive ion etch-front roughening Jason T. Drotar, Y.-P. Zhao, T.-M. Lu, and G.-C. Wang
. The etching products are volatile and desorb from the sample. Usually, for plasma etching, the gas pressure of growth front roughening phenomena in physical vapor condensation PVC including sputtering, molecular beam in the plasma sheath collide with gas atoms and molecules. Some atoms and molecules are dissociated or ionized
Wang, Gwo-Ching
The Science of the Total Environment 294 (2002) 131159 0048-9697/02/$ -see front matter 2002 Elsevier Science B.V. All rights reserved.
Hydrology is a primary control on the ecological quality of river systems, through its influence on flowThe Science of the Total Environment 294 (2002) 131159 0048-9697/02/$ - see front matter 2002 Elsevier Science B.V. All rights reserved. PII: S0048-9697Z02.00060-8 Hydrology and the ecological quality
Heal, Kate
ICPIG, July 15-20, 2007, Prague, Czech Republic C9 Heavy particle impact excitation of atomic oxygen in front of the powered
was assumed. Collision between O2 + and the background gas O2 generate electronically excited atomic oxygen oxygen in front of the powered electrode of oxygen rf plasmas Experiment and PIC-Simulation K. Dittmann) resolved plasma induced optical emission of the atomic oxygen in an asymmetrical oxygen rf plasma (CCP
Fehske, Holger
Gravity currents in a two-layer stratified ambient: The theory for the steady-state (front condition) and lock-released flows, and experimental
Gravity currents in a two-layer stratified ambient: The theory for the steady- state (front://pof.aip.org/features/most_downloaded Information for Authors: http://pof.aip.org/authors #12;PHYSICS OF FLUIDS 24, 026601 (2012) Gravity currents February 2012) We consider the propagation of a gravity current of density c at the bottom of a two
Flynn, Morris R.
A Nested Micro-Scale Simulation of a Lake Michigan Land-Breeze Front Gijs de Boer,Gregory J.Tripoli,Edwin W.Eloranta
Experiments (LAKE-ICE) on 21 December 1997,the University of Wisconsin Volume Imaging Lidar (UW-VIL) observedA Nested Micro-Scale Simulation of a Lake Michigan Land-Breeze Front Gijs de Boer,Gregory J.Tripoli,Edwin W.Eloranta Department of Atmospheric and Oceanic Sciences,The University of Wisconsin - Madison
PERGAMON Corrosion Science 30 "0888# 080084 9909!827X:87:, ! see front matter 0887 Elsevier Science Ltd[ All rights reserved[
\\ PERGAMON Corrosion Science 30 "0888# 080Ð084 9909!827X:87:, ! see front matter �? 0887 Elsevier Science Ltd[ All rights reserved[ PII] S9909!827X "87#99007!7 E}ect of strain rate on stress corrosion rate "SR# on the stress corrosion crack propagation rate "CPR#\\ for strain rates covering a wide range
Serebrinsky, Santiago A.
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