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An Integrated Experimental and Numerical Study: Developing a Reaction
Open Energy Info (EERE)
Integrated Experimental and Numerical Study: Developing a Reaction Integrated Experimental and Numerical Study: Developing a Reaction Transport Model that Couples Chemical Reactions of Mineral Dissolution/Precipitation with Spatial and Temporal Flow Variations in CO2/Brine/Rock Systems Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title An Integrated Experimental and Numerical Study: Developing a Reaction Transport Model that Couples Chemical Reactions of Mineral Dissolution/Precipitation with Spatial and Temporal Flow Variations in CO2/Brine/Rock Systems Project Type / Topic 1 Recovery Act: Enhanced Geothermal Systems Component Research and Development/Analysis Project Type / Topic 2 Supercritical Carbon Dioxide / Reservoir Rock Chemical Interactions Project Description This project will result in a numerical simulator (modified version of TOUGH2) that can adjust porosity and permeability fields according to experimentally observed chemical fluid-rock interactions (mineral dissolution/precipitation) under realistic conditions likely found when supercritical CO2 is injected into geothermal reservoirs for heat energy extraction. The simulator can thus help determine if CO2 injection into EGS brines will cause clogging of pore spaces or dissolution of host rocks with potentially detrimental consequences to heat extraction. As a result, this simulator will play a critical role when assessing long-term sustainability of geothermal energy utilization in enhanced and natural geothermal systems. The simulator can also be used to evaluate long-term CO2 sequestration potentials.
An Integrated Experimental and Numerical Study: Developing a...
and natural geothermal systems. The simulator can also be used to evaluate long-term CO2 sequestration potentials. State Minnesota Objectives Modify a numerical simulator (TOUGH2)...
NREL Developing Numerical Simulation Tool to Study Hydrokinetic...
NLE Websites -- All DOE Office Websites (Extended Search)
M.; Li, Y.; Moriarty, P. (2012). "A Large-Eddy Simulation Study of Wake Propagation and Power Production in an Array of Tidal-Current Turbines." Accepted by Proceedings of the...
A Numerical Study of the Development of Claud-Street Spacing
Science Conference Proceedings (OSTI)
Two-dimensional numerical computations of the developing boundary layer with a positive surface heat flux are presented. The model incorporates moisture phase-change effects; we are particularly interested in the cloud-street formation. The ...
R. I. Sykes; W. S. Lewellen; D. S. Henn
Structure of the Atmospheric Boundary Layer in the Vicinity of a Developing Upslope Flow System: A Numerical Model Study
The development of a morning upslope flow is studied by means of idealized numerical simulations. In particular, two cases are examined: a plane slope connecting a lower plain and an elevated plateau and a symmetric mountain in the middle of a ...
Stefano Serafin; Dino Zardi
NREL Developing a Numerical Simulation Tool to Study Hydrokinetic Energy Conversion Devices and Arrays (Fact Sheet)
New code will help accelerate design improvements by providing a high-fidelity simulation tool to study power performance, structural loading, and the interactions between devices in arrays.
Not Available
A Real-Data Numerical Study of the Development of Precipitation along the Edge of an Elevated Mixed Layer
An 18-h numerical simulation of the weather associated with the severe-storm outbreak in the region of the Texas-Oklahoma panhandles, during the AVE-SESAME IV study period (9�10 May 1979), was performed using the Pennsylvania State University/...
Mercedes N. Lakhtakia; Thomas T. Warner
Numerical Simulations of Air�Sea Interaction under High Wind Conditions Using a Coupled Model: A Study of Hurricane Development
In this study, a coupled atmosphere�ocean wave modeling system is used to simulate air�sea interaction under high wind conditions. This coupled modeling system is made of three well-tested model components: The Pennsylvania State University�...
J-W. Bao; J. M. Wilczak; J-K. Choi; L. H. Kantha
Numerical Modeling Studies of a Process of Lee Cyclogenesis
A process of lee cyclogenesis associated with backsheared baroclinic flow is studied using a fully nonlinear, primitive equation numerical model. A region of low pressure and a narrow baroclinic zone develop to the southwest of the mountain in ...
Yuh-Lang Lin; Donald J. Perkey
19 17 19 17 DE82 022279 NUMERICAL STUDIES OF ~MPURITIES IN FUSION PLASMAS* __ ~ -_ R. A. Hulse Plasma P h y s i c s L a b o r a t o r y , P r i n c e t o n U n i v e r s i t y P r i n c e t o n , New Jersey 08544 ABSTRACT me coupled p a r t i a l d i f f e r e n t i a l e q u a t i o n s used t o d e s c r i b e t h e b e h a v i o r of i m p u r i t y i o n s i n m a g n e t i c a l l y c o n f i n e d c o n t r o l l e d f u s i o n plasmas r e q u i r e n u m e r i c a l s o l u t i o n f o r cases of p r a c t i c a l i n t e r e s t . Computer codes developed f o r i m p u r i t y modeling a t t h e P r i n c e t o n Plasma P h y s i c s L a b o r a t o r y are used as examples of t h e t y p e s of codes employed f o r t h i s purpose. These codes s o l v e f o r t h e i m p u r i t y i o n i z a t i o n s t a t e d e n s i t i e s and a s s o c i a t e d r a d i a t i o n r a t e s u s i n g a t o m i c p h y s i c s a p p r o p r i a t e f o r t h e s e low-density, high-temperature plasmas. The s i m p l e r codes s o l v e l o c a l e q u a t i o n s i n z
Numerical simulations to study solar wind turbulence
Numerical simulation of coupled equations of kinetic Alfven wave (KAW) and ion acoustic wave is presented in the solar wind. The nonlinear dynamical equations satisfy the modified Zakharov system of equations by taking the nonadiabatic response of the background density. The ponderomotive nonlinearity is incorporated in the wave dynamics. The effect of Landau damping of KAW is taken into account. Localization of magnetic field intensity and the wavenumber spectra (perpendicular and parallel) of magnetic fluctuations are studied in solar plasmas around 1 a.u. Our results reveal the formation of damped localized structures and the steeper spectra that are in good agreement with the observations. These damped structures and steeper turbulent spectra can be responsible for plasma heating and particle acceleration in solar wind.
Sharma, R. P.; Sharma, Nidhi; Kumar, Sanjay [Centre for Energy Studies, Indian Institute of Technology Delhi, Delhi 110016 (India); Kumar, Sachin [Department of Applied Sciences and Humanities, Ajay Kumar Garg Engineering College, Ghaziabad 201009 (India); Singh, H. D. [Department of Physical Sciences, School of Physical and Chemical Sciences, Sikkim University, Sikkim 737102 (India)
Thunderstorm Electrification�A Numerical Study
The results of a numerical model of thunderstorm electrification that includes riming electrification compare favorably with many cloud observations. A strong electric charge accumulates through two major stages in the cloud: Stage 1 occurs near ...
Tsutomu Takahashi
Numerical Model Studies of Long-Period Edge Waves
A numerical modeling study of aspects of the generation and propagation of long-period edge waves along a continental shelf is described. The numerical model is based on the traditional shallow-water dynamics. A scale analysis indicates that ...
F. A. Shillington; D. Van Foreest
A Numerical Study of an Extreme Cold-Air Outbreak over the Labrador Sea: Sea Ice, Air�Sea Interaction, and Development of Polar Lows
In this paper, the ability of the MM5 mesoscale forecast model to simulate the air�sea interaction, boundary layer development, and mesoscale structure associated with a cold-air outbreak over the Labrador Sea is investigated. The case chosen was ...
Mariusz Pagowski; G. W. K. Moore
Study of detonation process: numerical approach
This paper is based on non-linear finite element analysis of the effects of the blast wave on structures, caused by the detonation of explosive materials. Dynamic response of a pipeline subjected to the shock wave produced by the detonation of high explosive ... Keywords: blast, coupling, explosive, numerical analysis, pipeline, safety
Jerzy Malachowski
Numerical and Laboratory Study of a Horizontally Evolving Convective Boundary Layer. Part I: Transition Regimes and Development of the Mixed Layer
Results are presented from a large eddy simulation (LES) and wind tunnel study of the turbulence regime in a horizontally evolving sheared atmospheric convective boundary layer (CBL) capped by a temperature inversion. The wind tunnel part of the ...
E. Fedorovich; F. T. M. Nieuwstadt; R. Kaiser
A Numerical Case Study of Convection Initiation along Colliding Convergence Boundaries in Northeast Colorado
A numerical cloud model has been used to simulate convective storm development on 17 July 1987 in northeast Colorado. The study involves the simulation of convergence along atmospheric boundaries and the subsequent development of convection. The ...
Bruce D. Lee; Richard D. Farley; Mark R. Hjelmfelt
Numerical study of a ventilated facade panel
An energy-saving facade panel for non-residential buildings has been numerically investigated. Structured like a composite Trombe-Michel wall, the panel consists of a glazing, an absorber plate and insulation and contains a dead air space between glazing and absorber, as well as a convection channel between absorber and insulation. The influence of convection channel spacing on both recovery of solar energy during sunshine periods and on heat losses during night hours has been assessed. Two different options have been considered. First, the total panel thickness was maintained, which involves an increase of channel spacing having to be compensated by a corresponding decrease of the insulation thickness. Then, this constraint was removed so that an increase in channel spacing was allowed to entail an equivalent increase of the total panel thickness. The results indicate that large spacing favors energy recovery during sunshine periods for both options and reduces, although only slightly, heat losses during night hours for the second option. In the case of the first option, however, these losses tend to grow when channel spacing increases. 15 refs., 5 figs.
Mootz, F.; Bezian, J.J. [Centre d`Energetique de l`Ecole des Mines de Paris (France)
Numerical study of thermal decomposition and pressure ...
... [6] A. Atreya, Pyrolysis, ignition and flame ... [10] MG Gronli, A theoretical and experimental study on the thermal degradation of biomass, Ph.D. thesis ...
A Numerical Study of Thermal Effects on Flow and Pollutant Dispersion in Urban Street Canyons
This study investigates thermal effects on the flow and pollutant dispersion in urban street canyons. A two-dimensional numerical model with a k�? turbulent closure scheme is developed, and the heat transfer between the air and the building wall ...
Jae-Jin Kim; Jong-Jin Baik
A Numerical Study of a Rotating Downburst
Previous studies have revealed that convective storms often contain intense small-scale downdrafts, termed �downbursts,� that are a significant hazard to aviation. These downbursts sometimes possess strong rotation about their vertical axis in ...
David B. Parsons; Morris L. Weisman
A Numerical Study of Two-Dimensional Moist Baroclinic Instability
A study of baroclinic instability in the presence of moisture is performed with a primitive equation nonhydrostatic two-dimensional numerical model. A new assumption regarding the meridional structure of the perturbation mixing ratio is discussed ...
Maurizio Fantini
A Numerical Study of a Southeast Australian Coastal Ridging Event
A numerical study of the 9�11 November 1982 southeast Australian coastal ridging event is presented. The mesoscale coastal features of this event have been previously described as a coastally trapped disturbance (CTD). However, the analysis ...
K. J. Tory; C. J. C. Reason; P. L. Jackson
A Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing
Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing in Mixed-Phase Stratiform Clouds Gijs de Boer, Tempei Hashino, Edwin W. Eloranta and Gregory J. Tripoli The University of Wisconsin - Madison (1) Introduction (1) Introduction Mixed-phase stratiform clouds are commonly observed at high latitudes (Shupe et al., 2006; de Boer et al., 2009a). These clouds significaly impact the atmospheric radiative
Numerical study of error propagation in Monte Carlo depletion simulations
Improving computer technology and the desire to more accurately model the heterogeneity of the nuclear reactor environment have made the use of Monte Carlo depletion codes more attractive in recent years, and feasible (if not practical) even for 3-D depletion simulation. However, in this case statistical uncertainty is combined with error propagating through the calculation from previous steps. In an effort to understand this error propagation, a numerical study was undertaken to model and track individual fuel pins in four 17 x 17 PWR fuel assemblies. By changing the code's initial random number seed, the data produced by a series of 19 replica runs was used to investigate the true and apparent variance in k{sub eff}, pin powers, and number densities of several isotopes. While this study does not intend to develop a predictive model for error propagation, it is hoped that its results can help to identify some common regularities in the behavior of uncertainty in several key parameters. (authors)
Wyant, T.; Petrovic, B. [Nuclear and Radiological Engineering, Georgia Inst. of Technology, 770 State Street, Atlanta, GA 30332-0745 (United States)
Numerical studies of gravity effects in two-phase reservoirs
DOE Green Energy (OSTI)
Numerical studies are performed to investigate the effects of localized feed zones on the pressure transients in two-phase reservoirs. It is shown that gravity effects can significantly affect the pressure transients, because of the large difference in the density of liquid water and vapor. Pressure transients for shallow and deep feed zones and the resulting fluid flow patterns are discussed.
Bodvarsson, G.S.; Cox, B.L.
Numerical studies on the geomechanical stability ofhydrate-bearing sediments
The thermal and mechanical loading of oceanicHydrate-Bearing Sediments (HBS) can result in hydrate dissociation and asignificant pressure increase, with potentially adverse consequences onthe integrity and stability of the wellbore assembly, the HBS, and thebounding formations. The perception of HBS instability, coupled withinsufficient knowledge of their geomechanical behavior and the absence ofpredictive capabilities, have resulted in a strategy of avoidance of HBSwhen locating offshore production platforms, and can impede thedevelopment of hydrate deposits as gas resources.In this study weinvestigate in three cases of coupled hydraulic, thermodynamic andgeomechanical behavior of oceanic hydrate-bearing sediments. The firstinvolves hydrate heating as warm fluids from deeper conventionalreservoirs ascend to the ocean floor through uninsulated pipesintersecting the HBS. The second case describes system response duringgas production from a hydrate deposit, and the third involves mechanicalloading caused by the weight of structures placed on the ocean flooroverlying hydrate-bearing sediments.For the analysis of the geomechanicalstability of HBS, we developed and used a numerical model that integratesa commercial geomechanical code and a simulator describing the coupledprocesses of fluid flow, heat transport and thermodynamic behavior in theHBS. Our simulation results indicate that the stability of HBS in thevicinity of warm pipes may be significantly affected, especially if thesediments are unconsolidated and more compressible. Gas production fromoceanic deposits may also affect the geomechanical stability of HBS underthe conditions that are deemed desirablefor production. Conversely, theincreased pressure caused by the weight of structures on the ocean floorincreases the stability of underlying hydrates.
Rutqvist, Jonny; Moridis, George J.
Numerical Investigation of Heat Transfer to Fully Developed Turbulent Air Flow in a Concentric Pipe
Numerical simulation using standard k-e turbulencemodel was developed to investigate numerically thecharacteristic of backward-facing step flow in a concentricpipe. This research is focused on the surface temperature, localheat transfer coefficient and ... Keywords: Numerical Simulation, Heat Transfer, Turbulent Flow, Computational Fluid Dynamics, Backward Facing Step
Cheen Sean Oon, Ahmad Badarudin, Salim Newaz Kazi, Arif Syazwan
The Numerical Simulation of Conventional Ground Coalbed Methane Development
The migration, accumulation, and production of coalbed methane (CBM) are absolutely different from the conventional natural gas. The mechanism of the migration and production of CBM are researched and the geological model of CBM reservoir simulation ... Keywords: coalbed methane, numerical simulation, desportion-diffusion, two phase flow, fully implicit finite difference
Lin Xiaoying; Liu Guowei; Su Xianbo
Numerical Studies of Particle Laden Flow in Dispersed Phase
E-Print Network (OSTI)
To better understand the hydrodynamic flow behavior in turbulence, Particle-Fluid flow have been studied using our Direct Numerical(DNS) based software DSM on MUSCL-QUICK and finite volume algorithm. The particle flow was studied using Eulerian-Eulerian Quasi Brownian Motion(QBM) based approach. The dynamics is shown for various particle sizes which are very relevant to spray mechanism for Industrial applications and Bio medical applications.
Dutta, R
1 Numerical study of dense adjoint 2-color matter ?
We study the global symmetries of SU(2) gauge theory with N flavors of staggered fermions in the presence of a chemical potential. We motivate the special interest of the case N = 1 (staggered) with fermions in the adjoint representation of the gauge group. We present results from numerical simulations with both hybrid Monte Carlo and the Two-Step Multi-Bosonic algorithm. 1.
Simon H; Istv�n Montvay B; Manfred Oevers C; Luigi Scorzato A; Jonivar Skullerud B
Numerical Approach for Development of High Elastic Casting ...
This study is suggested how to make high elastic aluminum alloys using ... Frequency Modulation Effect on the Solidification of Alloy 718 Fusion Zone.
Progress report on LBL's numerical modeling studies on Cerro Prieto
An exploitation model of the Cerro Prieto geothermal system is needed to assess the energy capacity of the field, estimate its productive lifetime and develop an optimal reservoir management plan. The model must consider the natural state (i.e., pre-exploitation) conditions of the system and be able to predict changes in the reservoir thermodynamic conditions (and fluid chemistry) in response to fluid production (and injection). This paper discusses the results of a three-dimensional numerical simulation of the natural state conditions of the Cerro Prieto field and compares computed and observed pressure and temperature/enthalpy changes for the 1973--1987 production period. 16 refs., 24 figs., 2 tabs.
Halfman-Dooley, S.E.; Lippman, M.J.; Bodvarsson, G.S.
The relative strength between forward and reverse shock emission in early gamma-ray burst (GRB) afterglow reflects that of magnetic energy densities in the two shock regions. We numerically show that with the current standard treatment, the fireball magnetization is underestimated by up to two orders of magnitude. This discrepancy is especially large in the sub-relativistic reverse shock regime (i.e., the thin shell and intermediate regime), where most optical flashes were detected. We provide new analytic estimates of the reverse shock emission based on a better shock approximation, which well describe numerical results in the intermediate regime. We show that the reverse shock temperature at the onset of afterglow is constant, ( {Gamma}-bar{sub d}-1){approx}8 Multiplication-Sign 10{sup -2}, when the dimensionless parameter {xi}{sub 0} is more than several. Our approach is applied to case studies of GRB 990123 and 090102, and we find that magnetic fields in the fireballs are even stronger than previously believed. However, these events are still likely to be due to a baryonic jet with {sigma} {approx} 10{sup -3} for GRB 990123 and {approx}3 Multiplication-Sign 10{sup -4} to 3 for GRB 090102.
Harrison, Richard; Kobayashi, Shiho, E-mail: email@example.com [Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom)
Decontamination solution development studies
SciTech Connect
This study was conducted for the Westinghouse Hanford Company (WHC) by Pacific Northwest Laboratory (PNL) as part of the Hanford Grout Technology Program (HGTP). The objective of this study was to identify decontamination solutions capable of removing radioactive contaminants and grout from the Grout Treatment Facility (GTF) process equipment and to determine the impact of these solutions on equipment components and disposal options. The reference grout used in this study was prepared with simulated double-shell slurry feed (DSSF) and a dry blend consisting of 40 wt % limestone flour, 28 wt % blast furnace slag, 28 wt % fly ash, and 4 wt % type I/II Portland cement.
Allen, R.P.; Fetrow, L.K.; Kjarmo, H.E.; Pool, K.H.
The Vishniac instability is thought to explain the complex structure of radiative supernova remnants in their Pressure-Driven Thin Shell (PDTS) phase after a blast wave (BW) has propagated from a central explosion. In this paper, the propagation of the BW and the evolution of the PDTS stage are studied numerically with the two-dimensional (2D) code HYDRO-MUSCL for a finite-thickness shell expanding in the interstellar medium (ISM). Special attention is paid to the adiabatic index, {gamma}, and three distinct values are taken for the cavity ({gamma}{sub 1}), the shell ({gamma}{sub 2}), and the ISM ({gamma}{sub 3}) with the condition {gamma}{sub 2} < {gamma}{sub 1}, {gamma}{sub 3}. This low value of {gamma}{sub 2} accounts for the high density in the shell achieved by a strong radiative cooling. Once the spherical background flow is obtained, the evolution of a 2D-axisymmetric perturbation is computed from the linear to the nonlinear regime. The overstable mechanism, previously demonstrated theoretically by E. T. Vishniac in 1983, is recovered numerically in the linear stage and is expected to produce and enhance anisotropies and clumps on the shock front, leading to the disruption of the shell in the nonlinear phase. The period of the increasing oscillations and the growth rate of the instability are derived from several points of view (the position of the perturbed shock front, mass fluxes along the shell, and density maps), and the most unstable mode differing from the value given by Vishniac is computed. In addition, the influence of several parameters (the Mach number, amplitude and wavelength of the perturbation, and adiabatic index) is examined and for wavelengths that are large enough compared to the shell thickness, the same conclusion arises: in the late stage of the evolution of the radiative supernova remnant, the instability is dampened and the angular initial deformation of the shock front is smoothed while the mass density becomes uniform with the angle. As a result, our model shows that the supernova remnant returns to a stable evolution and the Vishniac instability does not lead to the fragmentation of the shock as predicted by the theory.
Michaut, C.; Cavet, C.; Bouquet, S. E.; Roy, F.; Nguyen, H. C., E-mail: firstname.lastname@example.com [LUTH, Observatoire de Paris, CNRS, Universite Paris-Diderot, F-92190 Meudon (France)
Numerical and experimental studies of thermosiphon passive heating systems
A numerical analysis was used to predict the performance of a thermosiphon passive solar heating system. The numerical method is an adaptation of the PASOLE code including a calculation procedure for flow in the thermosiphon channel. A Los Alamos National Laboratory test cell was used to obtain experimental data for several configurations. Comparisons of experimentally measured collector surface temperatures and auxiliary heating energy requirements, with values predicted by numerical simulations, showed good agreement for the system without a backdraft damper. Experiments were also run using a backdraft damper consisting of a Tedlar flap and wire mesh covering the upper vent. Comparisons of experimental data with the results of a numerical simulation indicated that this relatively crude damper was approximately 35% effective.
Schnurr, N.M.; Wray, W.O.
Numerical Studies of Tritium and Helium-3 in the Thermocline
The effects of circulation and lateral mixing on the distributions of tritium and heliurn-3 in the thermocline are investigated using a two-dimensional numerical model. The gyre circulation was approximated by a steady flow with closed ...
David L. Musgrave
A Numerical Study of Cirrus Clouds. Part I: Model Description
This article, the first of a two-part series, presents a detailed description of a two-dimensional numerical cloud model directed toward elucidating the physical processes governing the evolution of cirrus clouds. The two primary scientific ...
Hui-Chun Liu; Pao K. Wang; Robert E. Schlesinger
A Numerical Study of Loop Current Intrusions and Eddy Shedding
The dynamics of the eddy shedding by the Loop Current in the Gulf of Mexico have been investigated using three nonlinear numerical models: two-layer, barotropic and reduced gravity. The barotropic and reduced gravity models demonstrate the ...
H. E. Hurlburt; J. Dana Thompson
Numerical Study on Flow Pass of a Three-Dimensional Obstacle under a Strong Stratification Condition
A three-dimensional, nonhydrostatic, numerical turbulent model was used to study the flow pass of a three-dimensional obstacle under a strong stratification condition. The numerical results clarify the behavior of the flow at a low Froude number, ...
W. Sha; K. Nakabayashi; H. Ueda
Remote connector development study
Plutonium-uranium extraction (PUREX) connectors, the most common connectors used at the Hanford site, offer a certain level of flexibility in pipe routing, process system configuration, and remote equipment/instrument replacement. However, these desirable features have inherent shortcomings like leakage, high pressure drop through the right angle bends, and a limited range of available pipe diameters that can be connect by them. Costs for construction, maintenance, and operation of PUREX connectors seem to be very high. The PUREX connector designs include a 90{degree} bend in each connector. This increases the pressure drop and erosion effects. Thus, each jumper requires at least two 90{degree} bends. PUREX connectors have not been practically used beyond 100 (4 in.) inner diameter. This study represents the results of a survey on the use of remote pipe-connection systems in US and foreign plants. This study also describes the interdependence between connectors, remote handling equipment, and the necessary skills of the operators.
Parazin, R.J.
Windback seals work similarly to labyrinth seals except for the effect of helical groove. These seals are essentially a tooth on stator or tooth on rotor labyrinth seal where the grooves are a continuous helical cut like a thread. Windback seals are used in centrifugal gas compressor to keep oil out of the gas face seal area. These face seals cannot be contaminated by oil. A purge gas is applied to the seal to help force the oil back into the bearing area. The windback seal should be designed to prevent any oil contamination into the supply plenum and to reduce purge gas leakage. The CFD simulations have been performed with the effect of clearance, tooth width, cavity shape, shaft rotation, eccentricity, and tooth location on the seal leakage performance and the flow field inside the seal. The leakage flow rate increases with increasing the pressure differential, rotor speed, radial clearance, cavity size, and shaft diameter and with decreasing the tooth width. The eccentricity has a minimal effect for the windback seal. From oil simulations, the windback seal with 25% rotor eccentricity has some of the journal bearing action and drives back flow into the gas plenum. However the windback seal can be used to force the oil back into the bearing side before starting the compressor by applying a purge gas flow since the positive axial velocity inside the cavity is larger than the negative axial velocity. m A Rw cav & / ? is constant for varying shaft rotation since the leakage flow rate for the windback seal increases linearly as the the rotor speed increases. The leakage flow rate for the windback seal increases as the groove size increases due to the pumping action of the windback seal. A windback seal design based upon the numerical simulations that minimize gas leakage and help prevent gas face seal oil contamination was optimized. The windback seal has two leakage flow paths. Since the leakage flow rate under teeth of windback seals is the same as for a similar geometry labyrinth seal, the flow under the teeth can be predicted by two-dimensional labyrinth seal analysis. An empirical model for the leakage rate through the cavity has been developed which fits the data with a standard deviation of 0.12.
Lim, Chae H.
A numerical study of bench blast row delay timing and its influence on percent-cast
The computer program, DMC (Distinct Motion Code), which was developed for simulating the rock motion associated with blasting, has been used to study the influence of row delay timing on rock motion. The numerical simulations correspond with field observations in that very short delays (< 50ms) and very long delays (> 300ms) produce a lower percent-cast than a medium delay (100 to 200 ms). The DMC predicted relationship between row delay timing and percent-cast is more complex than expected with a dip in the curve where the optimum timing might be expected. More study is required to gain a full understanding of this phenomenon.
Preece, D.S.
Development of analytical and numerical models for the assessment and interpretation of hydrogeological field tests
Mathematical models of the flow and tracer tests in fractured aquifers are being developed for the further study of radioactive wastes migration in round water at the Lake Area, which is associated with one of the waste disposal site in Russia. The choice of testing methods, tracer types (chemical or thermal) and the appropriate models are determined by the nature of the ongoing ground-water pollution processes and the hydrogeological features of the site under consideration. Special importance is attached to the increased density of wastes as well as to the possible redistribution of solutes both in the liquid phase and in the absorbed state (largely, on fracture surfaces). This allows for studying physical-and-chemical (hydrogeochemical) interaction parameters which are hard to obtain (considering a fractured structure of the rock mass) in laboratory. Moreover, a theoretical substantiation is being given to the field methods of studying the properties of a fractured stratum aimed at the further construction of the drainage system or the subsurface flow barrier (cutoff wall), as well as the monitoring system that will evaluate the reliability of these ground-water protection measures. The proposed mathematical models are based on a tight combination of analytical and numerical methods, the former being preferred in solving the principal (2D axisymmetrical) class of the problems. The choice of appropriate problems is based on the close feedback with subsequent field tests in the Lake Area. 63 refs.
Mironenko, V.A.; Rumynin, V.G.; Konosavsky, P.K. [St. Petersburg Mining Inst. (Russian Federation); Pozdniakov, S.P.; Shestakov, V.M. [Moscow State Univ. (Russian Federation); Roshal, A.A. [Geosoft-Eastlink, Moscow (Russian Federation)
Numerical study of reaction in porous catalysts under composition modulation
be solved numerically ALLOCATE(CIM(ngz,ntc),CIV(2,nciv)) !k=k+1; ! index of CIV CIM(j,i)=k; ! store column index ofstore column index of C ELSE CIM(j,i)=0; END IF ELSEIF (i>=
Hsiao, Hsu-Wen
A numerical study of fluid solid interaction in screw compressors
Efforts are continually being made to produce screw compressors with smaller clearances in order to reduce internal leakage. However, since the compression process induces large pressure differences across the rotors and temperature rise, they deform. ... Keywords: analytical grid generation, clearance reduction, compressor deformation, compressor performance, fluid solid interaction, fuid flow, internal leakage reduction, numerical simulation, rotor deflection, screw compressors
Ahmed Kovacevic; Nikola Stosic; Ian K. Smith
A Numerical Study of Water Injection on Transonic Compressor Rotor Performance.
??In this study, numerical simulations of two-phase flow in a transonic compressor rotor (NASA Rotor 37) were performed. Both flow and droplets governing equations were� (more)
Szabo, Istvan
Numerical Simulation Study on Transpired Solar Air Collector
The unglazed transpired solar air collector is now a well-recognized solar air heater for heating outside air directly. In this article, researchers introduced numerical simulation tools into the solar air collector research area, analyzed the performance characteristics of the unglazed transpired solar air collector and compared them with several kinds of traditional solar air collectors. The results showed that the unglazed transpired solar air collector has unparalleled advantages in the ventilation preheating area and also proves that CFD tools have their own advantages in the solar air collector research area.
Wang, C.; Guan, Z.; Zhao, X.; Wang, D.
Development of a carburizing and quenching simulation tool: numerical simulations of rings and gears
The ability to accurately calculate temperatures, stresses and metallurgical transformations in a single calculation or in a sequence of calculations is the key to prediction of distortion, residual stress and phase distribution in quench hardened automotive parts. Successful predictions in turn rely on the adequacy of the input data to the calculational procedure. These data include mechanical and thermal properties of the alloy phases over the range of temperature and strain rates experienced during the heat treat process, the mathematical description of the transformation kinetics, and the accuracy of the heat transfer boundary conditions. In this presentation we describe a calculational procedure using the ABAQUS{sup (1)} finite element code that simulates a carburizing and quench heat treat cycle for automotive gears. The calculational procedure features a numerically efficient 2-phase constitutive model, developed as part of the NCMS-Heat Treatment Distortion Prediction program, to represent transformational plasticity effects for the austenite/martensite Deformation together with refined finite element meshes to capture the steep gradients in stress and composition near the gear surfaces. The calculational procedure is illustrated on carburizing and quenching of a thick ring and comparison of model predictions for distortion, phase distribution, and residual stress with experimental measurements are discussed. Included in this model study is an investigation of the sensitivity of the predictions to mesh refinement.
Anderson, C.; Godlman, P.; Rangaswamy, P. [and others
Analytical and Numerical Studies of the Complex Interaction of a Fast Ion Beam Pulse with a Background Plasma
Plasma neutralization of an intense ion beam pulse is of interest for many applications, including plasma lenses, heavy ion fusion, high energy physics, etc. Comprehensive analytical, numerical, and experimental studies are underway to investigate the complex interaction of a fast ion beam with a background plasma. The positively charged ion beam attracts plasma electrons, and as a result the plasma electrons have a tendency to neutralize the beam charge and current. A suite of particle-in-cell codes has been developed to study the propagation of an ion beam pulse through the background plasma. For quasi-steady-state propagation of the ion beam pulse, an analytical theory has been developed using the assumption of long charge bunches and conservation of generalized vorticity. The analytical results agree well with the results of the numerical simulations. The visualization of the data obtained in the numerical simulations shows complex collective phenomena during beam entry into and ex it from the plasma.
Igor D. Kaganovich; Edward A. Startsev; Ronald C. Davidson
A Numerical Study of the Warm Rain Process in Orographic Clouds
A technique for numerical simulation of a stationary, two-dimensional laminar flow process is described. Based on this technique, a model for warm rain microphysics in an orographic cloud was developed. The model includes condensation, ...
Naihui Song; John Marwitz
Laboratory�Numerical Model Comparisons of Canyon Flows: A Parameter Study
An integrated set of laboratory and numerical-model experiments has been conducted to understand the development of residual circulation surrounding a coastal canyon and to explore further the degree to which laboratory experiments can provide ...
Don L. Boyer; Dale B. Haidvogel; Nicolas P�renne
Development of a numerical computer code and circuit element models for simulation of firing systems
Numerical simulation of firing systems requires both the appropriate circuit analysis framework and the special element models required by the application. We have modified the SPICE circuit analysis code (version 2G.6), developed originally at the Electronic Research Laboratory of the University of California, Berkeley, to allow it to be used on MSDOS-based, personal computers and to give it two additional circuit elements needed by firing systems--fuses and saturating inductances. An interactive editor and a batch driver have been written to ease the use of the SPICE program by system designers, and the interactive graphical post processor, NUTMEG, supplied by U. C. Berkeley with SPICE version 3B1, has been interfaced to the output from the modified SPICE. Documentation and installation aids have been provided to make the total software system accessible to PC users. Sample problems show that the resulting code is in agreement with the FIRESET code on which the fuse model was based (with some modifications to the dynamics of scaling fuse parameters). In order to allow for more complex simulations of firing systems, studies have been made of additional special circuit elements--switches and ferrite cored inductances. A simple switch model has been investigated which promises to give at least a first approximation to the physical effects of a non ideal switch, and which can be added to the existing SPICE circuits without changing the SPICE code itself. The effect of fast rise time pulses on ferrites has been studied experimentally in order to provide a base for future modeling and incorporation of the dynamic effects of changes in core magnetization into the SPICE code. This report contains detailed accounts of the work on these topics performed during the period it covers, and has appendices listing all source code written documentation produced.
Carpenter, K.H. (Kansas State Univ., Manhattan, KS (USA). Dept. of Electrical and Computer Engineering)
A Numerical Modeling Study of the Upwelling Source Waters along the Oregon Coast during 2005
Regional ocean circulation along the Oregon coast is studied numerically for forcing fields derived from year 2005 and climatological-mean conditions. The primary object is to study directly the Lagrangian pathways by which fluid arrives in the ...
David Rivas; R. M. Samelson
An experimental and numerical study of wind turbine seismic behavior
of Turbine Rotor . . . . . . . . . . . . . . 3.9 Results ofA. C. (2006). �WindPACT turbine rotor design study. � ReportA. C. (2006). �WindPACT turbine rotor design study. � Report
Prowell, I.
Numerical study of 2D heat transfer in a scraped surface heat exchanger
Numerical study of 2D heat transfer in a scraped surface heat exchanger K.-H. Sun a,*, D.L. Pyle heat exchanger with non- Newtonian power law fluids is undertaken. Numerical results are generated of scraped surface heat exchanger design are assessed in the light of the results. �? 2003 Elsevier Ltd. All
Numerical Study of Gravity Currents in a Channel
A three-dimensional primitive-equation model was used to study gravity currents produced by instantaneous releases of a buoyant fluid in a rectangular channel. Without rotation, the gravity current passes through two distinct phases: an initial ...
Dong-Ping Wang
Numerical study of boundary layer injection as a scale control method
A boundary layer injection method of controlling scale-buildup in geothermal two-phase flow nozzles is studied. The object of this study is to set an upper limit on the ratio of the injected mass flow rate to the free stream mass flow rate that is necessary to isolate the scale carrying free stream flow from the nozzle wall. In order to develop a numerical model of the boundary layer flow, assumptions are made which reduce the results to order of magnitude approximations. Two configurations of nozzles with various injection flow rates are tried. It is found by numerical experiment that a nozzle with injection through a 1 mm thick ring near the inlet, is more efficient at isolating the free stream than a porous nozzle. A mass flow rate ratio of 0.173% was necessary to achieve this effect. It may be concluded that an upper limit on the mass flow rate ratio is about 2.0% with injection through a ring near the inlet, and that boundary layer injection is a reasonable method of controlling scale-buildup. A glossary of variables, program documentation and listings are presented for programs GMD15SR8, TRACK11, and TRACK12.
Feiereisen, W.
Wind-Forced Downwelling Slope Currents: A Numerical Study
A study is made of the dynamics of slope currents that arise from a steady, constant alongshore wind over a uniform shelf. Over the first 10�20 days, the evolution of the downwelled system on an f plane is qualitatively described by linear ...
John F. Middleton; Mauro Cirano
A Numerical Study of Lapse-Rate Adjustments in the Tropical Atmosphere
Observations in the tropics have shown that the lapse rate of virtual Potential temperature ?v normally resembles that of a reversible moist adiabat. In the present study, a mesoscale numerical model with parameterized convection is used to ...
Charles Cohen; William M. Frank
Numerical Studies of the Beta Effect in Tropical Cyclone Motion. Part II: Zonal Mean Flow Effects
The motion of tropical vortices in east�west mean flows is studied with the barotropic vorticity equation on the beta plane. The vorticity equation is integrated numerically from an initially symmetric vortex embedded in (i) a linear shear flow ...
R. T. Williams; Johnny C-L. Chan
A Numerical Study of the Mesoscale Environment Of a Southerly Buster Event
A numerical case study of a Southerly Buster event that occurred on 1 December 1982 during the Southerly Buster Observational Program (SUBOP) is presented. Southerly busier refers to the leading edge of a coastally trapped gravity currentlike ...
Peter A. C. Howells; Ying-Hwa Kuo
A Numerical Study of the Genesis of Tropical Storms Observed during the FGGE Year
This study utilizes the First GARP Global Experiment's (FGGE) analyzed dataset and a relatively fine scale regional model in combination to investigate the feasibility of numerically simulating tropical disturbances during the FGGE year, 1979. ...
Robert E. Tuleya
Experimental and Numerical Study of the Turbulence Characteristics of Airflow around a Research Vessel
Airflow distortion by research vessels has been shown to significantly affect micrometeorological measurements. This study uses an efficient time-dependent large-eddy simulation numerical technique to investigate the effect of the R/V Tangaroa on ...
St�phane Popinet; Murray Smith; Craig Stevens
Numerical Study of the Influence of Environmental Conditions on Lake-Effect Snowstorms over Lake Michigan
Numerical simulations are used to examine the influence of environmental parameters on the morphology of lake effect snowstorms over Lake Michigan. A series of model sensitivity studies are performed using the Colorado State University mesoscale ...
Mark R. Hjelmfelt
Numerical Study on GRB-Jet Formation in Collapsars
Two-dimensional magnetohydrodynamic simulations are performed using the ZEUS-2D code to investigate the dynamics of a collapsar that generates a GRB jet, taking account of realistic equation of state, neutrino cooling and heating processes, magnetic fields, and gravitational force from the central black hole and self gravity. It is found that neutrino heating processes are not so efficient to launch a jet in this study. It is also found that a jet is launched mainly by B{sub {phi}} fields that are amplified by the winding-up effect. However, since the ratio of total energy relative to the rest mass energy in the jet is not so high as several hundred, we conclude that the jets seen in this study are not be a GRB jet. This result suggests that general relativistic effects, which are not included in this study, will be important to generate a GRB jet. Also, the accretion disk with magnetic fields may still play an important role to launch a GRB jet, although a simulation for much longer physical time {approx} 10-100 s is required to confirm this effect. It is shown that considerable amount of {sup 56}Ni is synthesized in the accretion disk. Thus there will be a possibility for the accretion disk to supply sufficient amount of {sup 56}Ni required to explain the luminosity of a hypernova. Also, it is shown that neutron-rich matter due to electron captures with high entropy per baryon is ejected along the polar axis. Moreover, it is found that the electron fraction becomes larger than 0.5 around the polar axis near the black hole by {nu}{sub e} capture at the region. Thus there will be a possibility that r-process and r/p-process nucleosynthesis occur at these regions. Finally, much neutrons will be ejected from the jet, which suggests that signals from the neutron decays may be observed as the delayed bump of the light curve of the afterglow or gamma-rays.
Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park; Takahashi, Rohta; /Tokyo U.; Mizuta, Akira; /Garching, Max Planck Inst.; Takiwaki, Tomoya; /Tokyo U.
Numerical study of domain coarsening in anisotropic stripe patterns
We study the coarsening of two-dimensional smectic polycrystals characterized by grains of oblique stripes with only two possible orientations. For this purpose, an anisotropic Swift-Hohenberg equation is solved. For quenches close enough to the onset of stripe formation, the average domain size increases with time as $t^{1/2}$. Further from onset, anisotropic pinning forces similar to Peierls stresses in solid crystals slow down defects, and growth becomes anisotropic. In a wide range of quench depths, dislocation arrays remain mobile and dislocation density roughly decays as $t^{-1/3}$, while chevron boundaries are totally pinned. We discuss some agreements and disagreements found with recent experimental results on the coarsening of anisotropic electroconvection patterns.
Denis Boyer
Comprehensive Mechanisms for Combustion Chemistry: An Experimental and Numerical Study with Emphasis on Applied Sensitivity Analysis
This project was an integrated experimental/numerical effort to study pyrolysis and oxidation reactions and mechanisms for small-molecule hydrocarbon structures under conditions representative of combustion environments. The experimental aspects of the work were conducted in large-diameter flow reactors, at 0.3 to 18 atm pressure, 500 to 1100 K temperature, and 10-2 to 2 seconds reaction time. Experiments were also conducted to determine reference laminar flame speeds using a premixed laminar stagnation flame experiment and particle image velocimetry, as well as pressurized bomb experiments. Flow reactor data for oxidation experiments include: (1)adiabatic/isothermal species time-histories of a reaction under fixed initial pressure, temperature, and composition; to determine the species present after a fixed reaction time, initial pressure; (2)species distributions with varying initial reaction temperature; (3)perturbations of a well-defined reaction systems (e.g. CO/H2/O2 or H2/O2)by the addition of small amounts of an additive species. Radical scavenging techniques are applied to determine unimolecular decomposition rates from pyrolysis experiments. Laminar flame speed measurements are determined as a function of equivalence ratio, dilution, and unburned gas temperature at 1 atm pressure. Hierarchical, comprehensive mechanistic construction methods were applied to develop detailed kinetic mechanisms which describe the measurements and literature kinetic data. Modeling using well-defined and validated mechanisms for the CO/H2/Oxidant systems and perturbations of oxidation experiments by small amounts of additives were also used to derive absolute reaction rates and to investigate the compatibility of published elementary kinetic and thermochemical information. Numerical tools were developed and applied to assess the importance of individual elementary reactions to the predictive performance of the developed mechanisms and to assess the uncertainties in elementary rate constant evaluations.
Dryer, Frederick L.
Development of a carburizing and quenching simulation tool: Numerical simulations of rings and gears
This paper describes a calculational procedure using the ABAQUS finite element code that simulates a carburizing and quench heat treat cycle for automotive gears. The procedure features a numerically efficient 2-phase constitutive model to represent transformational plasticity effects for the austenite/martensite transformation together with refined finite element meshes to capture the steep gradients in stress and composition near the gear surfaces. The procedure is illustrated on carburizing and quenching of a thick ring, and comparison of model predictions for distortion, phase distribution, and residual stress with experiment is discussed. Sensitivity of predictions to mesh refinement is studied.
Anderson, C.; Goldman, P.; Rangaswamy, P. [Los Alamos National Lab., NM (United States)] [and others
Numerical Experiments on the Mechanisms for the Development and Maintenance of Long-Lived Squall Lines in Dry Environments
The mechanisms responsible for the development and maintenance of long-lived squall lines in dry environments are investigated through two-dimensional numerical experiments by using a nonhydrostatic cloud model. The squall line environments are ...
Tetsuya Takemi; Takehiko Satomura
New Mexico renewable development study
Since the early 1990s, Los Alamos National Laboratory (LANL) has applied electric grid models and simulation software to problems of national significance. This effort continues with a variety of other projects funded by the Department of Energy (DOE), other federal and state agencies and private companies. Critical to the success of these programs is the ability to integrate regional-scale models of the electric grid, to assess the propagation of grid impacts, and to present interactively the effect of potential mitigating actions required to stabilize the grid. All of these capabilities are applied in this study, to accomplish the following goals and objectives: (1) Develop an AC power flow model representing future conditions within New Mexico's electric grid, using commercial tools accepted by the utility industry; (2) Conduct a 'screening' analysis of options for accelerating potential renewable energy development through the addition of a statewide transmission collector system; (3) Estimate total revenue needed, jobs created (temporary and permanent) plus indirect and direct impacts to the state's economy; (4) Evaluate potential cost allocation methodology; and (5) Issue a project report that will provide information for policy direction by state regulators, project developers, and legislators.
Toole, Gasper [Los Alamos National Laboratory; Bent, Russell [Los Alamos National Laboratory; Ewers, Mary [Los Alamos National Laboratory
Analytical and Numerical Studies of the Beta-Effect in Tropical Cyclone Motion. Part I: Zero Mean Flow
The ?-effect on tropical cyclone motion is studied using an analytical as well as a numerical model in a nondivergent barotropic framework. The analytical model and the linear version of the numerical model give essentially the same result: the ...
Johnny C. L. Chan; R. T. Williams
Electrohydrodynamic induction and conduction pumping of dielectric liquid film: theoretical and numerical studies
Electrohydrodynamic (EHD) pumping of single and two-phase media is attractive for terrestrial and outer space applications since it is non-mechanical, lightweight, and involves no moving parts. In addition to pure pumping purposes, EHD pumps are also used for the enhancement of heat transfer, as an increase in mass transport often translates to an augmentation of the heat transfer. Applications, for example, include two-phase heat exchangers, heat pipes, and capillary pumping loops. In this research, EHD induction pumping of liquid film in annular horizontal and vertical configurations is investigated. A non-dimensional analytical model accounting for electric shear stress existing only at the liquid/vapor interface is developed for attraction and repulsion pumping modes. The effects of all involved parameters including the external load (i.e. pressure gradient) and gravitational force on the nondimensional interfacial velocity are presented. A non-dimensional stability analysis of EHD induction pumping of liquid film in a vertical annular configuration in the presence of external load for repulsion mode is carried out. A general non-dimensional stability criterion is presented. Stability maps are introduced allowing classification of pump operation as stable or unstable based on the input operating parameters. An advanced numerical model accounting for the charges induced throughout the bulk of the fluid due to the temperature gradient for EHD induction pumping of liquid film in a vertical annular configuration is derived. A non-dimensional parametric study including the effects of external load is carried out for different entrance temperature profiles and in the presence of Joule heating. Finally, a non-dimensional theoretical model is developed to investigate and to understand the EHD conduction phenomenon in electrode geometries capable of generating a net flow. It is shown that with minimal drag electrode design, the EHD conduction phenomenon is capable of providing a net flow. The theoretical model is further extended to study the effect of EHD conduction phenomenon for a two-phase flow (i.e. a stratified liquid/ vapor medium). The numerical results presented confirm the concept of liquid film net flow generation with the EHD conduction mechanism.
Al Dini, Salem A. S.
Numerical study of flow and heat transfer in 3D serpentine channels using colocated grids
channels, which have applications in heat-exchangers, were studied. A finite-volume code in FORTRAN was developed to solve this problem. Modules were made for generating rids in the domain, for valving the flow velocities and pressure, for solving temperature field and for post-processing the results. For solving the flow field, colocated grid formulation was used as opposed to the staggered-grid formulation, and the SIMPLE algorithm was used to link the velocity and pressure. The line-by-line method was used to solve the algebraic equations. The geometry of the problem facilitated the application of periodic inverted symmetry boundary condition. Since this is a forced convection problem, the flow field was solved first and the converged velocity field was input to the temperature solver module. The temperature field was solved for the uniform-wall-heat-flux boundary condition. The post-processing module obtained the overall friction-factor, which is representative of the pressure drop, the local and average Nusselt number. The numerical code developed was validated by solving for fully developed flow and heat transfer in a square straight channel. Grid-independent solution was established for a reference case of serpentine channel with the highest Reynolds number (Re=200). Periodically fully developed flow and heat transfer in serpentine channels were salved for different geometry parameters, for different Reynolds numbers and for two different Prandtl numbers ( 0.7 and 7.0 for air and water respectively). The results were plotted to study the effect of the independent parameters on the pressure drop and the heat transfer performance. The friction factor increased as the amplitude of the serpentine channel and the Reynolds number were increased. Similar trend was observed for the heat transfer coefficients. High heat transfer coefficients are observed at certain regions in the serpentine channels which are explained by the impingement phenomena. High Prandtl number (=7.0) gives higher heat transfer coefficients than the low Pr (=0.7) because of the thinner thermal boundary layer. The enhancement of heat transfer mechanism was explained by studying the plotted flow-field velocity vectors in different planes.
Chintada, Sailesh Raju
Numerical Study of Ultrasound Bioeffects by Solving Gas-Liquid-Solid Interaction Problems
Numerical Study of Ultrasound Bioeffects by Solving Gas-Liquid-Solid Interaction Problems and a nearby structure. First, a one-dimensional Gilmore model combined with gas diffusion was used to predict and bubble sizes. The results indicated gas diffusion had little influence on the maximum bubble radius
Goldman, Steven A.
A Numerical Simulation Study on the Genesis of a Tropical Storm
The genesis of a tropical storm is studied using a numerical simulation model. The model used is an 11-level primitive equation model covering a channel domain of 25� span with open lateral boundaries at latitudes 5.5 and 30.5�N. The initial ...
Yoshio Kurihara; Robert E. Tuleya
Aspects of the Mean Wintertime Circulation along Australia's Southern Shelves: Numerical Studies
A high-resolution numerical model is used to study the mean wintertime shelf-slope circulation between the Gulfs of South Australia and the west coast of Tasmania. The mean downwelling-favorable winds for the region result in a continuous ...
Mauro Cirano; John F. Middleton
A Numerical Case Study of the Squall Line of 6 May 1975
Results of moist and dry fine-mesh (140 km) numerical simulations of the 6 May 1975 Omaha squall line are presented. The moist fine-mesh simulation reproduced several observable features of the squall system and was then used to study other ...
C. B. Chang; D. J. Perkey; C. W. Kreitzberg
A Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing in Mixed-Phase Stratiform Clouds
freezing in a mixed-phase stratiform cloud. Immersion freez- ing is represented using a parameterization, and the larger droplets nucleate into ice particles through the immersion freezing process. In mixed-phaseA Numerical Sensitivity Study of Aerosol Influence on Immersion Freezing in Mixed-Phase Stratiform
Eloranta, Edwin W.
A Numerical Study on the Enhancement of Heat Transfer by Pressure Distributions in Acoustic Fields
The enhancement of heat transfer in a cavity was investigated in the absence of and in the presence of acoustic streaming induced by ultrasonic waves. The present study provides the experimental and numerical results of heat transfer in the acoustic ... Keywords: Acoustic pressure, Acoustic streaming, Coupled FE-BEM, Particle imaging velocimetry (PIV), Ultrasonic wave
Y. K. Oh; H. D. Yang
The Interaction between the Bottom Mixed layer and Mesoscale Motions of the Ocean: A Numerical Study
The interaction between a bottom mixed layer and a mesoscale eddy field is studied using a numerical model of a two-layer quasi-geostrophic fluid above a mixed layer. The height of the mixed layer is assumed to be restricted by stratification. A ...
K. J. Richards
A Numerical Study of the East Coast Snowstorm of 10�12 February 1983
A numerical study of the East Coast snowstorm of 10�12 February 1983 has been conducted with the NRL mesoscale model. The three-dimensional, hydrostatic, primitive equation model has 91 � 51 horizontal grid points with a half degree resolution in ...
Simon Chang; Katherine Brehme; Rangarao Madala; Keith Sashegyi
Sea-Breeze Interactions along a Concave Coastline in Southern Australia: Observations and Numerical Modeling Study
Observations and numerical modeling of the bay and ocean breezes of Port Phillip Bay show that the interaction of these two breezes produces features undocumented in previous sea-breeze studies. The first of these is the formation of a mesoscale ...
Deborah J. Abbs
Numerical Simulation and Multiple Realizations for Sensitivity Study of Shale Gas Reservoir
SPE 141058 Numerical Simulation and Multiple Realizations for Sensitivity Study of Shale Gas. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract Shale gas in the United States the largest conventional gas accumulations in the world. Shale gas success is directly the result
Mohaghegh, Shahab
A Three-Dimensional Numerical Study of an Oklahoma Squall Line Containing Right-Flank Supercells
A nonhydrostatic numerical mesoscale model has been applied to the study of an Oklahoma squall line with initial conditions taken from the Oklahoma�Kansas Preliminary Regional Experiment for STORM-Central (PRE-STORM) data for 7 May 1985. The ...
Jimy Dudhia; Mitchell W. Moncrieff
Low-Level Jet Development during a Numerically Simulated Return Flow Event
The evolution of the southerly low-level jet (LLJ) during a return flow event is studied using output from the Penn State/NCAR Mesoscale Model (Version 4). Three geographically different southerly LLJs develop in the simulation: one over the ...
Richard C. Igau; John W. Nielsen-Gammon
Numerical study of a matrix-free trust-region SQP method for equality constrained optimization.
This is a companion publication to the paper 'A Matrix-Free Trust-Region SQP Algorithm for Equality Constrained Optimization' [11]. In [11], we develop and analyze a trust-region sequential quadratic programming (SQP) method that supports the matrix-free (iterative, in-exact) solution of linear systems. In this report, we document the numerical behavior of the algorithm applied to a variety of equality constrained optimization problems, with constraints given by partial differential equations (PDEs).
Heinkenschloss, Matthias (Rice University, Houston, TX); Ridzal, Denis; Aguilo, Miguel Antonio
A Modeling Study on the Early Electrical Development of Tropical Convection: Continental and Oceanic (Monsoon) Storms
Numerical modeling studies of continental tropical and maritime tropical convection were conducted using the two-dimensional, nonhydrostatic, cloud electrification model developed at the South Dakota School of Mines and Technology. The model ...
Scot C. Randell; Steven A. Rutledge; Richard D. Farley; John H. Helsdon Jr.
Development of A595 Explosion?Resistant Container Design. Numerical, Theoretical and Experimental Justification of the Container Design Parameters
The paper presents the results of numerical and experimental study on the AT595 metal?composite container designed in VNIIEF within the framework of international collaboration with SNL (USA). This container must completely contain products of an 8?kg?TNT detonation cased in 35 kg of inert surrounding material. Numerical and theoretical studies have been carried out of the containment capacity and fracture of small?scale open cylinder test units and container pressure vessel models subjected to different levels of specific explosive load (beneath
A. I. Abakumov; I. V. Devyatkin; V. Yu. Meltsas; A. L. Mikhailov; G. F. Portnyagina; V. N. Rusak; V. P. Solovyev; M. A. Syrunin; S. M. Treshalin; A. G. Fedorenko
LBNL Developing Countries Studies | Open Energy Information
LBNL Developing Countries Studies LBNL Developing Countries Studies (Redirected from Developing Countries Studies) Jump to: navigation, search Logo: Developing Countries Studies at LBNL Name Developing Countries Studies at LBNL Agency/Company /Organization Lawrence Berkeley National Laboratory Sector Energy Focus Area Energy Efficiency Topics GHG inventory, Resource assessment, Background analysis Resource Type Dataset, Software/modeling tools, Presentation Website http://ies.lbl.gov/node/251 References Lawrence Berkeley [1] Abstract LBNL's International Energy Studies Group is involved in a number of activities relating to energy use in developing countries and climate change. LBNL's International Energy Studies Group is involved in a number of activities relating to energy use in developing countries and climate
A numerical study of the window condition for Chern numbers of Hofstadter Butterflies
Chern numbers for Hofstadter modes with rational flux p/q satisfy a Diophantine equation which determines them Mod(q). The resolution of the Mod(q) ambiguity is only known for the model of the rectangular lattice with nearest neighbors hopping. We have studied numerically the window condition for a Hofstadter butterfly on the triangular lattice with flux pi/2 through the down triangles. Our numerical finding suggest a simple window condition for all p and q even and for p not equal (q+1)/2 or (q-1)/2 for q odd. For these values the model is deformable to the square lattice without gap closure. For other values the window is complicated and mostly unknown implying that there are topological obstructions to deforming the model to the square lattice
J. E. Avron; O. Kenneth; G. Yeshoshua
TOUGH: a numerical model for nonisothermal unsaturated flow to study waste canister heating effects
The physical processes modeled and the mathematical and numerical methods employed in a simulator for non-isothermal flow of water, vapor, and air in permeable media are briefly summarized. The simulator has been applied to study thermo-hydrological conditions in the near vicinity of high-level nuclear waste packages emplaced in unsaturated rocks. The studies reported here specifically address the question whether or not the waste canister environment will dry up in the thermal phase. 13 references, 8 figures, 2 tables.
Pruess, K.; Wang, J.S.Y.
Numerical study of black-hole formation in Painleve-Gullstrand coordinates
We study numerically black-hole formation from a collapsing massless scalar field. The use of Painleve-Gullstrand coordinates allows the evolution to proceed until singularity formation. We generate spacetime maps of the collapse, illustrating the evolution of apparent horizons for various initial data. A study of the Choptuik scaling reveals the expected universal values for the critical exponent and echoing period. The periodic oscillations in the supercritical horizon scaling relation, while universal with respect to initial Painleve-Gullstrand data, show unexpected structure with large amplitude cusps.
Ziprick, Jonathan [Department of Physics and Winnipeg Institute of Theoretical Physics, University of Manitoba, Winnipeg, Manitoba (Canada); Kunstatter, Gabor [Department of Physics and Winnipeg Institute of Theoretical Physics, University of Winnipeg, Winnipeg, Manitoba (Canada)
Numerical study: Iron corrosion-resistance in lead-bismuth eutectic coolant by molecular dynamics method
In this present work, we report numerical results of iron (cladding) corrosion study in interaction with lead-bismuth eutectic coolant of advanced nuclear reactors. The goal of this work is to study how the oxygen can be used to reduce the corrosion rate of cladding. The molecular dynamics method was applied to simulate corrosion process. By evaluating the diffusion coefficients, RDF functions, MSD curves of the iron and also observed the crystal structure of iron before and after oxygen injection to the coolant then we concluded that a significant and effective reduction can be achieved by issuing about 2% number of oxygen atoms to lead-bismuth eutectic coolant.
Arkundato, Artoto; Su'ud, Zaki; Abdullah, Mikrajuddin; Widayani,; Celino, Massimo [Nuclear Physics and Biophysics Research Division, Physics Department Institut Teknologi Bandung, Jl. Ganesha 10, Bandung Physics Department, Faculty of Mathematical and Natural Sciences Universitas (Indonesia); Nuclear Physics and Biophysics Research Division, Physics Department Institut Teknologi Bandung, Jl. Ganesha 10, Bandung (Indonesia); ENEA, CR Cassacia, Via Anguillarese 301, Roma (Italy)
Production optimization of a tight sandstone gas reservoir with well completions: A numerical simulation study.
??Tight gas sands have significant gas reserves, which requires cost-effective well completion technology and reservoir development plans for viable commercial exploitation. In this study, a� (more)
Defeu, Cyrille W.
Development of a Two-Fluid Drag Law for Clustered Particles Using Direct Numerical Simulation and Validation through Experiments
Two-Fluid Drag Law Two-Fluid Drag Law for Clustered Particles Using Direct Numerical Simulation and Validation through Experiments Background The Historically Black Colleges and Universities and Other Minority Institutions (HBCU/ OMI) Research and Development (R&D) Program within the U. S. Department of Energy (DOE) Office of Fossil Energy (FE) provides a mechanism for cooperative FE R&D projects between DOE and the HBCU/OMI community. This program encourages
A reaction-based river/stream water quality model Part I: Model development and numerical schemes
This paper presents the conceptual and mathematical development of a numerical model of sediment and reactive chemical transport in river/streams. The distribution of mobile suspended sediments and immobile bed sediments is controlled by hydrologic transport as well as erosion and deposition processes. The fate and transport of water quality constituents involving a variety of chemical and physical processes is mathematically described by a system of reaction equations for immobile constituents and advective-dispersive-reactive transport equations for constituents. To circumvent stiffness associated with equilibrium reactions, matrix decomposition is performed via Gauss-Jordan column reduction. After matrix decomposition, the system of water quality constituent reactive transport equations is transformed into a set of thermodynamic equations representing equilibrium reactions and a set of transport equations involving no equilibrium reactions. The decoupling of equilibrium and kinetic reactions enables robust numerical integration of the partial differential equations for non-equilibrium-variables. Solving non-equilibrium-variable transport equations instead of individual water quality constituent transport equations also reduces the number of PDEs. A variety of numerical methods are investigated for solving the mixed differential and algebraic equations. Two verification examples are compared with analytical solutions to demonstrate the correctness of the code and to illustrate the importance of employing application-dependent numerical methods to solve specific problems.
Zhang, Fan [ORNL; Gour-Tsyh, Yeh [University of Central Florida, Orlando; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Jardine, Philip M [ORNL
Countries Studies Countries Studies Jump to: navigation, search Logo: Developing Countries Studies at LBNL Name Developing Countries Studies at LBNL Agency/Company /Organization Lawrence Berkeley National Laboratory Sector Energy Focus Area Energy Efficiency Topics GHG inventory, Resource assessment, Background analysis Resource Type Dataset, Software/modeling tools, Presentation Website http://ies.lbl.gov/node/251 References Lawrence Berkeley [1] Abstract LBNL's International Energy Studies Group is involved in a number of activities relating to energy use in developing countries and climate change. LBNL's International Energy Studies Group is involved in a number of activities relating to energy use in developing countries and climate change. Developed international energy use data and emissions scenarios for
Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot
Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.
Feng Liubin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Institute of Atomic and Molecular Physics and Department of Physics, Sichuan University, Chengdu 610065 (China); Lu Xin; Liu Xiaolong; Li Yutong; Chen Liming; Ma Jinglong; Dong Quanli; Wang Weimin [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Xi Tingting [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Sheng Zhengming; Zhang Jie [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Key Laboratory for Laser Plasmas of the Ministry of Education of China and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); He Duanwei [Institute of Atomic and Molecular Physics and Department of Physics, Sichuan University, Chengdu 610065 (China)
Numerical study on coupled fluid flow and heat transfer process in parabolic trough solar collector tube
A unified two-dimensional numerical model was developed for the coupled heat transfer process in parabolic solar collector tube, which includes nature convection, forced convection, heat conduction and fluid-solid conjugate problem. The effects of Rayleigh number (Ra), tube diameter ratio and thermal conductivity of the tube wall on the heat transfer and fluid flow performance were numerically analyzed. The distributions of flow field, temperature field, local Nu and local temperature gradient were examined. The results show that when Ra is larger than 10{sup 5}, the effects of nature convection must be taken into account. With the increase of tube diameter ratio, the Nusselt number in inner tube (Nu{sub 1}) increases and the Nusselt number in annuli space (Nu{sub 2}) decreases. With the increase of tube wall thermal conductivity, Nu{sub 1} decreases and Nu{sub 2} increases. When thermal conductivity is larger than 200 W/(m K), it would have little effects on Nu and average temperatures. Due to the effect of the nature convection, along the circumferential direction (from top to down), the temperature in the cross-section decreases and the temperature gradient on inner tube surface increases at first. Then, the temperature and temperature gradients would present a converse variation at {theta} near {pi}. The local Nu on inner tube outer surface increases along circumferential direction until it reaches a maximum value then it decreases again. (author)
Tao, Y.B.; He, Y.L. [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)
Coupled elastic-plastic thermomechanically assisted diffusion: Theory development, numerical implementation, and application
A fully coupled thermomechanical diffusion theory describing the thermal and mechanically assisted mass transport of dilute mobile constituents in an elastic solid is extended to include the effects of elastic-plastic deformation. Using the principles of modern continuum mechanics and classical plasticity theory, balance laws and constitutive equations are derived for a continuum composed of an immobile, but deformable, parent material and a dilute mobile constituent. The resulting equations are cast into a finite element formulation for incorporation into a finite element code. This code serves as a tool for modeling thermomechanically assisted phenomena in elastic-plastic solids. A number of simplified problems for which analytical solutions can be derived are used to benchmark the theory and finite element code. Potential uses of the numerical implementation of the theory are demonstrated using two problems. Specifically, tritium diffusion in a titanium alloy and hydrogen diffusion in a multiphase stainless steel are examined.
Weinacht, D.J.
Development of A595 Explosion-Resistant Container Design. Numerical, Theoretical and Experimental Justification of the Container Design Parameters
The paper presents the results of numerical and experimental study on the AT595 metal-composite container designed in VNIIEF within the framework of international collaboration with SNL (USA). This container must completely contain products of an 8-kg-TNT detonation cased in 35 kg of inert surrounding material. Numerical and theoretical studies have been carried out of the containment capacity and fracture of small-scale open cylinder test units and container pressure vessel models subjected to different levels of specific explosive load (beneath, equal to and above the required design load defined for this container), and two AT595 containers have been tested for the design load and a higher load.
Abakumov, A. I.; Devyatkin, I. V.; Meltsas, V. Yu.; Mikhailov, A. L.; Portnyagina, G. F.; Rusak, V. N.; Solovyev, V. P.; Syrunin, M. A.; Treshalin, S. M.; Fedorenko, A. G. [Russian Federal Nuclear Center - All-Russian Research Institute of Experimental Physics, 607190 Sarov (Russian Federation)
Numerical Weather Prediction Studies from the FGGE Southern Hemisphere Data Base
The quality of numerical weather prediction available for the Southern Hemisphere from the FGGE data base has been examined. The Australian Numerical Meteorology Research Centre (ANMRC) spectral prediction model has been initialized with analyses ...
W. Bourke; K. Puri; R. Seaman
A Numerical Study of the Role of Humidity in the Updraft Driven by Moist Slantwise Convection
A hydrostatic numerical model with simple microphysical parameterization is used to simulate moist slantwise convection (MSC) in an archetypal initial condition free of other kinds of instability. The numerical experiments are designed to explore ...
Valdir Innocentini; Ernesto Dos Santos Caetano Neto
Optimal homogenization of perfusion flows in microfluidic bio-reactors; a numerical study
To ensure homogeneous conditions within the complete area of perfused microfluidic bio-reactors, we develop a general design of a continuously feed bio-reactor with uniform perfusion flow. This is achieved by introducing a specific type of perfusion inlet to the reaction area. The geometry of these inlets are found using the methods of topology optimization and shape optimization. The results are compared with two different analytic models, from which a general parametric description of the design is obtained and tested numerically. Such a parametric description will generally be beneficial for the design of a broad range of microfluidic bioreactors used for e.g. cell culturing and analysis, and in feeding bio-arrays.
Okkels, Fridolin; Bruus, Henrik
A Numerical Study on Appearance of the Runaway Greenhouse State of a Three-Dimensional Gray Atmosphere
A numerical study on the runaway greenhouse state is performed by using a general circulation model (GCM) with simplified hydrologic and radiative processes. Except for the inclusion of three-dimensional atmospheric motion, the system utilized is ...
Masaki Ishiwatari; Shin-ichi Takehiro; Kensuke Nakajima; Yoshi-Yuki Hayashi
A Numerical Study of the Feedback Mechanisms of Hurricane�Environment Interaction on Hurricane Movement from the Potential Vorticity Perspective
The interaction between a hurricane and its environment is studied by analysing the generation and influence of potential vorticity (PV) from the Geophysical Fluid Dynamics Laboratory hurricane model analysis system. Two sets of numerical ...
Chun-Chieh Wu; Yoshio Kurihara
Numerical Study of Local/Regional Atmospheric Changes Caused by a Large Solar Central Receiver Power Plant
A two-dimensional, vertical cross section, numerical atmospheric mesoscale model has been applied to study the potential local/regional atmospheric effects of the installation of a 100 MWe solar thermal central receiver power plant at Barstow, ...
Chandrakant M. Bhumralkar; Arthur J. Slemmons; Kenneth C. Nitz
A Numerical Study of the Long- and Short-Term Temperature Variability and Thermal Circulation in the North Sea
A three-dimensional numerical study is presented of the seasonal, semimonthly, and tidal-inertial cycles of temperature and density-driven circulation within the North Sea. The simulations are conducted using realistic forcing data and are ...
Patrick J. Luyten; John E. Jones; Roger Proctor
A Multiscale Numerical Study of Hurricane Andrew (1992). Part V: Inner-Core Thermodynamics
Although considerable progress has been made in understanding the development of hurricanes, our knowledge of their three-dimensional structures of latent heat release and inner-core thermodynamics remains limited. In this study, the inner-core ...
Da-Lin Zhang; Yubao Liu; M. K. Yau
Numerical study on transient heat transfer under soil with plastic mulch in agriculture applications using a nonlinear finite element model
In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.
De Castro, Carlos Armando
Studying the Imaging Characteristics of Ultra Violet Imaging Telescope (UVIT) through Numerical Simulations
Ultra-Violet Imaging Telescope (UVIT) is one of the five payloads aboard the Indian Space Research Organization (ISRO)'s ASTROSAT space mission. The science objectives of UVIT are broad, extending from individual hot stars, star-forming regions to active galactic nuclei. Imaging performance of UVIT would depend on several factors in addition to the optics, e.g. resolution of the detectors, Satellite Drift and Jitter, image frame acquisition rate, sky background, source intensity etc. The use of intensified CMOS-imager based photon counting detectors in UVIT put their own complexity over reconstruction of the images. All these factors could lead to several systematic effects in the reconstructed images. A study has been done through numerical simulations with artificial point sources and archival image of a galaxy from GALEX data archive, to explore the effects of all the above mentioned parameters on the reconstructed images. In particular the issues of angular resolution, photometric accuracy and photometric...
Srivastava, Mudit K; Tandon, Shyam N
Numerical study of drying process and columnar fracture process in granules-water mixtures
The formation of three-dimensional prismatic cracks in the drying process of starch-water mixtures is investigated numerically. We assume that the mixture is an elastic porous medium which possesses a stress field and a water content field. The evolution of both fields are represented by a spring network and a phenomenological model with the water potential, respectively. We find that the water content distribution has a propagating front which is not explained by a simple diffusion process. The prismatic structure of cracks driven by the water content field is observed. The depth dependence and the coarsening process of the columnar structure are also studied. The particle diameter dependence of the scale of the columns and the effect of the crack networks on the dynamics of the water content field are also discussed.
Akihiro Nishimoto; Tsuyoshi Mizuguchi; So Kitsunezaki
A Study of the Influence of Terrain on Fog Development
A general purpose mesoscale numerical weather prediction model is used to simulate the development of fog at Perth, Western Australia, on 27 April 1990. Using one-dimensional and two-dimensional model configurations, an attempt is made to ...
B. W. Golding
Numerical studies of cold water injection into vapor-dominated geothermal systems
Recent reservoir pressure and steam flow rate declines at The Geysers geothermal field in California have attracted interest in studies of increased cold water injection into this system. In this paper, numerical studies of such injection into a fractured vapor-dominated reservoir are conducted using a two-dimensional radial, double-porosity model. The results obtained indicate that cold water injection into superheated (low-pressure) zones will greatly enhance the productivities of steam wells. Injection into two-phase zones with significant liquid reserves in the matrix blocks does not appear to aid in steam recovery until most of the original liquid reserves are depleted. Sensitivity studies are conducted over the range of fracture and matrix permeabilities applicable to the Geysers. The sensitivity of the grid size is also conducted, and shows very large grid effects. A fine vertical space discretization near the bottom of the reservoir is necessary to accurately predict the boiling of the injected water. 28 refs., 15 figs., 3 tabs.
Lai, C.H; Bodvarsson, G.S.
An experimental and numerical study of boundary layer structure over areas of inhomogeneous sensible heat fluxes
In June of 1992 a boundary-layer experiment was carried out near Boardman, Oregon. The campaigns were part of a program of studies under the auspices of the US Department of Energy`s Atmospheric Radiation Measurement (ARM) program, whose goal is to improve the treatment of radiative transfer, particularly as affected by clouds, in general circulation models (GCMs) used for climate studies. One aspect of this program is concerned with the determination of appropriate lower boundary conditions for such models and the representation of subgrid-scale variability in regions where the surface conditions are not uniform. To study this problem, boundary-layer and surface properties were measured over a region of two sharply contrasting land types: a large, dry, sagebrush steppe area and irrigated farmland that formed the east, northeast, and western borders of the steppe. A combination of surface flux instrumentation, airsondes, sodars, and near-surface wind and temperature sensors was used. Measurements were carried out over the eastern portion of this region, which featured a well-defined boundary between the dry and irrigated areas. In this paper, the authors present some results from those observations and from a set of numerical simulations that address the effects of inhomogeneous surface fluxes on boundary-layer structure.
Zhong, S.; Doran, J.C.
in each demand level, i.e. Ptdl grid , and the emission factor of the grid, i.e. Egrid. The total XNdl dl ¼ 1 sdl �? 2 4Egrid �? P grid t;dl þ XNb i ¼ 1 X dg Edg �? P dg i;t;dl 3 5 (13) 3. The proposed.7714 Table 2 Data used in the study. Parameter Unit Value T year 10 Np 50 Str MVA 40 Egrid kg emissions
Ketefian, Gerard
Numerical study of the disordered Poland-Scheraga model of DNA denaturation
We numerically study the binary disordered Poland-Scheraga model of DNA denaturation, in the regime where the pure model displays a first order transition (loop exponent $c=2.15>2$). We use a Fixman-Freire scheme for the entropy of loops and consider chain length up to $N=4 \\cdot 10^5$, with averages over $10^4$ samples. We present in parallel the results of various observables for two boundary conditions, namely bound-bound (bb) and bound-unbound (bu), because they present very different finite-size behaviors, both in the pure case and in the disordered case. Our main conclusion is that the transition remains first order in the disordered case: in the (bu) case, the disorder averaged energy and contact densities present crossings for different values of $N$ without rescaling. In addition, we obtain that these disorder averaged observables do not satisfy finite size scaling, as a consequence of strong sample to sample fluctuations of the pseudo-critical temperature. For a given sample, we propose a procedure to identify its pseudo-critical temperature, and show that this sample then obeys first order transition finite size scaling behavior. Finally, we obtain that the disorder averaged critical loop distribution is still governed by $P(l) \\sim 1/l^c$ in the regime $l \\ll N$, as in the pure case.
Thomas Garel; Cecile Monthus
Numerical Study of Terrain-Induced Mesoscale Motions in a Mixed Layer
Numerical integrations using a potential enstrophy conserving scheme are presented for the flow within a mixed layer over hilly terrain using the hydrostatic shallow-water equations with a quadratic drag law. The mesoscale area treated is 150 km ...
Y-J. Han; K. Ueyoshi; J. W. Deardorff
A Numerical Study of the Interaction between Stratocumulus and the Air Overlying It
The structure and evolution of stratocumulus cloud decks have long been recognized to depend upon a balance of numerous processes including the downward entrainment of the overlying free tropospheric air into the cloud deck. While the cloud is ...
Steven T. Siems; Donald H. Lenschow; Christopher S. Bretherton
The Rhine Outflow Plume Studied by the Analysis of Synthetic Aperture Radar Data and Numerical Simulations
The dynamics of the Rhine outflow plume in the proximity of the river mouth is investigated by using remote sensing data and numerical simulations. The remote sensing data consist of 41 synthetic aperture radar (SAR) images acquired by the First ...
Katrin Hessner; Angelo Rubino; Peter Brandt; Werner Alpers
Restratification of the Upper Ocean after the Passage of a Tropical Cyclone: A Numerical Study
The role of baroclinic instability in the restratification of the upper ocean after the passage of a tropical cyclone (TC) is determined by means of numerical simulations. Using a regional ocean model, the Regional Ocean Modeling System (ROMS), a ...
Wei Mei; Claudia Pasquero
A Numerical Simulation Study of the Effects of Anvil Shading on Quasi-Linear Convective Systems
Numerical simulations are used to investigate how the attenuation of solar radiation by the intervening cumulonimbus cloud, particularly its large anvil, affects the structure, intensity, and evolution of quasi-linear convective systems and the ...
Andrew J. Oberthaler; Paul M. Markowski
Numerical Study of the Local Downslope Wind �Hirodo-Kaze� in Japan
The �Hirodo-kaze,� a local strong wind accompanying the downslope winds in Japan, is examined using a mesoscale numerical model. The model successfully reproduces the major features of the observed Hirodo-kaze that occurred in association with ...
Hironori Fudeyasu; Tsuneo Kuwagata; Yukitaka Ohashi; Shin-ichi Suzuki; Yasutomo Kiyohara; Yu Hozumi
An Experimental and Numerical Study of the Internal Wave Generation by Tide�Topography Interaction
A stratified fluid response to barotropic oscillatory now over a large-amplitude obstacle is examined on the basis of the results of laboratory and numerical experiments. It is demonstrated that, when the obstacle height is fixed relative to the ...
Tomonori Matsuura; Toshiyuki Hibiya
A Numerical Study of a Squall Line over the Taiwan Strait during TAMEX IOP 2
A two-dimensional numerical cloud model was used to investigate a squall line that occurred over the Taiwan Strait on 16 May 1987 during TAMEX (Taiwan Area Mesoscale Experiment). This squall line illustrated multicellular behavior as revealed by ...
Ching-Sen Chen
A Numerical Modeling Study of Warm Offshore Flow over Cool Water
Numerical simulations of boundary layer evolution in offshore flow of warm air over cool water are conducted and compared with aircraft observations of mean and turbulent fields made at Duck, North Carolina. Two models are used: a two-dimensional,...
Eric D. Skyllingstad; Roger M. Samelson; Larry Mahrt; Phil Barbour
Evaluation of Numerical Predictions of Boundary Layer Structure during the Lake Michigan Ozone Study
The performance of two types of turbulence closures is compared in a 3D numerical investigation of an episode with poor air quality. The first is the Blackadar boundary layer scheme, which has a nonlocal closure for unstable conditions. The ...
Perry C. Shafran; Nelson L. Seaman; George A. Gayno
The Beta Drift of Three-Dimensional Vortices: A Numerical Study
The beta effect on translation of cyclonic and anticyclonic vortices with height-dependent circulation (the beta-drift problem) is investigated via numerical experiments using a dry version of a multilevel primitive equation model (Florida State ...
Bin Wang Xiaofan Li
On the Combined Effects of Turbulence and Gravity on Droplet Collisions in Clouds: A Numerical Study
This paper examines the combined influences of turbulence and gravity on droplet collision statistics in turbulent clouds by means of direct numerical simulation (DNS). The essential microphysical mechanisms that determine the geometric collision ...
Eric J. P. Woittiez; Harm J. J. Jonker; Lu�s M. Portela
A Numerical Study of the Thermally Driven Plain-to-Basin Wind over Idealized Basin Topographies
Numerical experiments have been carried out with a two-dimensional nonhydrostatic mesoscale model to investigate the diurnal temperature range in a basin and the thermally driven plain-to-basin winds. Under clear-sky conditions, the diurnal ...
Stephan F. J. de Wekker; Shiyuan Zhong; Jerome D. Fast; C. David Whiteman
A Numerical Study of Stratified Airflow over Mesoscale Heat Sources with Application to Carolina Coastal Frontogenesis
This paper presents the results from a numerical investigation of the responses of stratified airflow to prescribed near-surface mesoscale axisymmetric (circular) and elongated (elliptical) heat sources under uniform basic wind conditions using a ...
Lian Xie; Yuh-Lang Lin
Numerical and experimental studies of IFE target layering in a cryogenic fluidized bed
is fixed on the grid, only the heat flux or surfacethe heat equation is solved on a fixed grid, while theGrid Supported Marker Particle Scheme for Interface Tracking�, Numerical Heat
Boehm, Kurt Julian
A Theoretical and Numerical Study of Urban Heat Island�Induced Circulation and Convection
Urban heat island�induced circulation and convection in three dimensions are investigated theoretically and numerically in the context of the response of a stably stratified uniform flow to specified low-level heating that represents an urban ...
Ji-Young Han; Jong-Jin Baik
A Numerical Study of Flow and Pollutant Dispersion Characteristics in Urban Street Canyons
The flow and pollutant dispersion in urban street canyons are investigated using a two-dimensional numerical model with the k�? turbulent closure scheme. It is shown that the flow field is characterized mainly by the number and intensity of ...
Jong-Jin Baik; Jae-Jin Kim
A Numerical Study of a Mesoscale Convective System during TOGA COARE. Part II: Organization
In Part I, the authors presented a successful numerical simulation of the life cycle of a warm-pool mesoscale convective system (MCS) that occurred on 15 December 1992 during the Tropical Ocean Global Atmosphere Coupled Ocean�Atmosphere Response ...
Badrinath Nagarajan; M. K. Yau; Da-Lin Zhang
Daytime Boundary Layer Evolution over Mountainous Terrain. Part II: Numerical Studies of Upslope Flow Duration
Numerical simulators of upslope flow forming on the lee side of a heated mountain ridge showed this flow to be a transient phenomenon, in agreement with observations. The simulations, performed with a two-dimensional, dry version of the cloud ...
Robert M. Banta
A Numerical Study of the Mesoscale Atmospheric Circulation Observed during a Coastal Upwelling Event on 23 August 1972. Part I: Sensitivity Studies
A numerical model is used to study the effect of an Ocean surface temperature gradient on the mesoscale atmospheric circulation. The model is initialized with atmospheric data from 23 August 1972 over the central Oregon coastal zone. After the ...
Arthur Paul Mizzi; Roger A. Pielke
Numerical Simulations of the Effect of Soil Moisture and Vegetation Cover on the Development of Deep Convection
A one-dimensional (column) version of a primitive equations model has been used to study the impact of soil moisture and vegetation cover on the development of deep cumulus convection in the absence of dynamical forcing. The model includes ...
Craig A. Clark; Paymond W. Arritt
Comprehensive mechanisms for combustion chemistry: An experimental and numerical study with emphasis on applied sensitivity analysis
Over the last three years, this program has made significant progress on a number of problems: development of a data base for oxidation of the CO/H[sub 2]/O[sub 2] system; development and refinement of a comprehensive kinetic mechanism for the CO/H[sub 2]/O[sub 2] system; additional experiments on formaldehyde oxidation in the, comprehensive mechanistic studies inclusive of flow reactor results and literature results from static reactors, shock tubes, and flames, and identification of elementary reactions needing further study; mechanistic study of previously acquired APFR flow reactor data on ethanol oxidation, including an estimation of the branching ratios for C[sub 2]H[sub 5]0H + X, X= OH,H and identification of elementary reactions needing additional study; completion and mechanistic evaluation of the first insitu optical diapostic measurements of OH in the APFR; determinations of uni-molecular decomposition rate for 1,3,5-Trioxane at 700 to 800 K; seeded perturbation experiments on moist CO oxidation in flow reactors as a means to determine elementary rate constants for specific reactions; determination of elementary rates for CH[sub 4] + OH [yields] CH[sub 3] + H[sub 2]0 at 1026 and 1140 K, and C[sub 3]H[sub 6] + OH [yields] products at 1020 K; First experimental studies of the H[sub 2]/O[sub 2] reaction system in the VPFR at conditions between the extended second and third explosion limits.
Dryer, F.L.; Yetter, R.A.
Numerical Simulation Study to Investigate Expected Productivity Improvement Using the "Slot-Drill" Completion
The "slot-drill" completion method, which utilizes a mechanically cut high-conductivity "slot" in the target formation created using a tensioned abrasive cable, has been proposed as an alternative stimulation technique for shale-gas and other low/ultra-low permeability formations. This thesis provides a comprehensive numerical simulation study on the "slot drill" completion technique. Using a Voronoi gridding scheme, I created representative grid systems for the slot-drill completion, as well as for the case of a vertical well with a single fracture, the case of a horizontal well with multiple hydraulic fractures, and various combinations of these completions. I also created a rectangular slot configuration, which is a simplified approximation of the actual "slot-drill" geometry, and investigated the ability of this rectangular approximation to model flow from the more complicated (actual) slot-drill configuration(s). To obtain the maximum possible diagnostic and analytical value, I simulated up to 3,000 years of production, allowing the assessment of production up to the point of depletion (or boundary-dominated flow). These scenarios provided insights into all the various flow regimes, as well as provided a quantitative evaluation of all completion schemes considered in the study. The results of my study illustrated that the "slot-drill" completion technique was not, in general, competitive in terms of reservoir performance and recovery compared to the more traditional completion techniques presently in use. Based on my modeling, it appears that the larger surface area to flow that multistage hydraulic fracturing provides is much more significant than the higher conductivity achieved using the slot-drill technique. This work provides quantitative results and diagnostic interpretations of productivity and flow behavior for low and ultra-low permeability formations completed using the slot-drill method. The results of this study can be used to (a) help evaluate the possible application of the "slot-drill" technique from the perspective of performance and recovery, and (b) to establish aggregated economic factors for comparing the slot-drill technique to more conventional completion and stimulation techniques applied to low and ultra-low permeability reservoirs.
Odunowo, Tioluwanimi Oluwagbemiga
Experimental and numerical study of the effective thermal conductivity of silica nanocomposites with thermal boundary resistance
The thermal interface resistance at the macro scale is mainly described by the physical gap between two interfaces and constriction resistance due to this gap. The small gaps between the two material faces makes up the majority of thermal interface resistance at the macro scale. So, most of the studies have been focused on characterizing effect of surface geometry and material properties to thermal interface resistance. This resistance is more widely known as thermal contact resistance, represented with Rc. There are various models to predict thermal contact resistance at macro scale. These models predict thermal resistance Rc for given two materials by utilizing their bulk thermomechanical properties. Although, Rc represents thermal resistance accurately for macro size contacts between two metals, it is not suitable to describe interface resistance of particles in modern TIMs, aka particulate composites. The particles inside recently available TIMs are micron size and with effort to further increase surface area this particle size is approaching nano scale. At this small scale, Rc does not accurately predict thermal interface, as it is very difficult to characterize the surface topography. The thermal discontinuity at perfectly bonded interface of two dissimilar materials is termed as thermal boundary resistance (Rb) or Kapitza resistance. The macroscopic assumptions that thermal discontinuity only exists due to gaps and surface geometry leads to substantial error in determining interface thermal properties at micron and nano scale. The phenomenon of thermal boundary resistance is an inherent material property and arises due to fundamental mechanism of thermal transport. For metal-matrix particulate composites, Rb plays more important role than Rc. The free flowing nature of the polymer would eliminate most of the gaps between the two materials at their interface. This means almost all of the thermal resistance at particle/matrix interface would occur due to Rb. The current study presents experimental study of thermal boundary resistance for silica nano particles embedded inside epoxy resin. The bulk conductivity of the sample is measured and Rc is back calculated using Hasselman-Johnson s (H-J) equation. The numerical validation of the equation is also presented, including extrapolation study to predict effective conductivity of the nanocomposite TIM.
Kothari, Rushabh M [ORNL; Dinwiddie, Ralph Barton [ORNL; Wang, Hsin [ORNL
Analytic and numerical study of the free energy in gauge theory
We derive some exact bounds on the free energy W(J) in an SU(N) gauge theory, where J_mu^b is a source for the gluon field A_mu^b in the minimal Landau gauge, and W(J) is the generating functional of connected correlators, exp W(J) = . We also provide asymptotic expressions for the free energy W(J) at large J and for the quantum effective action Gamma(A) at large A. We specialize to a source J(x)=h cos(kx) of definite momentum k and source strength h, and study the gluon propagator D(k,h) in the presence of this source. Among other relations, we prove int_0^inf dh D(k,h)0) D(k,h) = 0, for all positive h>0. Thus the system does not respond to a static color probe, no matter how strong. Recent lattice data in minimal Landau gauge in d =3 and 4 dimensions at h=0 indicate that the gluon propagator in the minimum Landau gauge is finite, lim_(k->0) D(k,0)>0. Thus these lattice data imply a jump in the value of D(k,h) at h=0 and k=0, and the value of D(k,h) at this point depends on the order of limits. We also present numerical evaluations of the free energy W(k,h) and the gluon propagator D(k,h) for the case of SU(2) Yang-Mills theory in various dimensions which support all of these findings.
Axel Maas; Daniel Zwanziger
Numerical Study of the Effects of Atmospheric and Wake Turbulence on Wind Turbine Dynamics
Although the atmospheric sciences community has been studying the effects of atmospheric stability and surface roughness on the planetary boundary layer for some time, their effects on wind turbine dynamics have not been well studied. In this study, we performed numerical experiments to explore some of the effects of atmospheric stability and surface roughness on wind turbine dynamics. We used large-eddy simulation to create atmospheric winds and compute the wind turbine flows, and we modeled the wind turbines as revolving and flexible actuator lines coupled to a wind turbine structural and system dynamic model. We examined the structural moments about the wind turbine blade, low-speed shaft, and nacelle; power production; and wake evolution when large 5-MW turbines are subjected to winds generated from low- and high-surface roughness levels representative of offshore and onshore conditions, respectively, and also neutral and unstable atmospheric conditions. In addition, we placed a second turbine 7 rotor diameters downwind of the first one so that we could explore wake effects under these different conditions. The results show that the turbulent structures generated within the atmospheric boundary layer wind simulations cause isolated loading events at least as significant as when a turbine is waked by an upwind turbine. The root-mean-square (RMS) turbine loads are consistently larger when the surface roughness is higher. The RMS blade-root out-of-plane bending moment and low-speed shaft torque are higher when the atmospheric boundary layer is unstable as compared with when it is neutral. However, the RMS yaw moments are either equal or reduced in the unstable case as compared with the neutral case. For a given surface roughness, the ratio of power produced by the downwind turbine relative to that of the upwind turbine is 15-20% higher when the conditions are unstable as compared with neutral. For a given atmospheric stability, this power ratio is 10% higher with the onshore roughness value versus the offshore one. The main conclusion is that various coherent turbulent structures that form under different levels of atmospheric stability and surface roughness have important effects on wind turbine structural response, power production, and wake evolution.
Churchfield, M. J.; Lee, S.; Michalakes, J.; Moriarty, P. J.
A Numerical Study of a Low-level Jet and Its Accompanying Secondary Circulation in a Mei-Yu System
A primitive equation numerical model has been used to study the Mei-Yu system that occurred in the middle of May 1987. Although cumulus heating was not included in one of the experiments, all of the major features of a Mei-Yu system other than ...
Wu-Ron Hsu; Wen-Yih Sun
CO2-Driven Enhanced Gas Recovery and Storage in Depleted Shale Reservoir-A Numerical Simulation Study
1 CO2-Driven Enhanced Gas Recovery and Storage in Depleted Shale Reservoir- A Numerical Simulation for storage and enhanced gas recovery may be organic-rich shales, which CO2 is preferentially adsorbed comprehensive simulation studies to better understand CO2 injection process in shale gas reservoir. This paper
A Numerical Study of Breaking Kelvin-Helmholtz Billows using a Reynolds-Stress Turbulence Closure Model
A two-dimensional numerical study of breaking Kelvin-Helmholtz billows is presented. The turbulent breaking process is modeled using second-order closure methods to describe the small-wale turbulence, while the large-scale billow itself is ...
R. I. Sykes; W. S. Lewellen
Note on numerical study of the beam energy spread in NDCX-I
The kinetic energy spread (defined here as the standard deviation of the beam particle energies) sets the ultimate theoretical limit on the longitudinal compression that can be attained on NDCX-I and NDCX-II. Experimental measurements will inevitably include the real influences on the longitudinal phase space of the beam due to injector and accelerator field imperfections1. These induced energy variations may be the real limit to the longitudinal compression in an accelerator. We report on a numerical investigation of the energy spread evolution in NDCX-I; these studies do not include all the real imperfections, but rather are intended to confirm that there are no other intrinsic mechanisms (translaminar effects, transverse-longitudinal anisotropy instability, etc.) for significant broadening of the energy distribution. We have performed Warp simulations that use a realistic Marx voltage waveform which was derived from experimental measurements (averaged over several shots), a fully-featured model of the accelerating and focusing lattice, and new diagnostics for computing the local energy spread (and temperature) that properly account for linear correlations that arise from the discrete binning along each physical dimension (these capabilities reproduce and extend those of the earlier HIF code BPIC). The new diagnostics allow for the calculation of multi-dimensional maps of energy spread and temperature in 2-D axisymmetric or 3-D Cartesian space at selected times. The simulated beam-line was terminated at z = 3 m by a conducting plate, so as to approximately reproduce the experimental conditions at the entrance of the spectrometer that was used for mapping the longitudinal phase space. Snapshots of the beam projection and current, as well as the Marx waveform and history of beam kinetic energy collected at the end plate, are shown in Fig. 1. A two-dimensional axisymmetric map of energy spread from simulations of a typical NDCX-I configuration is shown in Fig. 2 (a). The energy spread starts at 0.1 eV at the source and rapidly rises to a few eV, then fluctuates between a fraction of an eV and tens of eV, ending near the exit in a range of a few eV at the outer edge of the beam to a few tens of eV near the axis. The higher value on-axis is associated with greater numerical noise there, due to the axisymmetric geometry of the calculation, resulting in poorer simulation-particle statistics at small radius. A scatter plot of the macroparticles kinetic energy (KE) versus radius (R) and longitudinal position (0.28 m < z < 3 m) colored by local energy spread is shown in Fig. 2 (b). As expected, there is a correlation of the kinetic energy with radius that is clearly visible at z = 2.8 m and vanishes at the metal plate at z = 3 m. More snapshots from simulations varying the time step, grid resolution and number of macroparticles are given in Appendix II. The macro-particles were collected at the exit plate and their kinetic energy history is plotted in Fig. 3 (left) and contrasted to an experimental measurement using a streak camera shown in Fig. 3. For some types of measurements, averaging over several pulses to improve signal-to-noise will contribute an additional spread that may not be present on any single beam pulse. The upper bound for the energy spread is in the range of a few 100 eV for the experiment while in the range of a few eV for the reported Warp simulations. The Marx voltage exhibits variations in the range of up to several hundreds of volts, playing a significant role in the experimentally measured energy spread, which may account for the difference between the experimental and the simulated bounds.
Vay, J.-L.; Seidl, P.A.; Friedman, A.
The kinetic energy spread (defined here as the standard deviation of the beam particle energies) sets the ultimate theoretical limit on the longitudinal compression that can be attained on NDCX-I and NDCX-II. Experimental measurements will inevitably include the real influences on the longitudinal phase space of the beam due to injector and accelerator field imperfections1. These induced energy variations may be the real limit to the longitudinal compression in an accelerator. We report on a numerical investigation of the energy spread evolution in NDCX-I; these studies do not include all the real imperfections, but rather are intended to confirm that there are no other intrinsic mechanisms (translaminar effects, transverse-longitudinal anisotropy instability, etc.) for significant broadening of the energy distribution. We have performed Warp simulations that use a realistic Marx voltage waveform which was derived from experimental measurements (averaged over several shots), a fully-featured model of the accelerating and focusing lattice, and new diagnostics for computing the local energy spread (and temperature) that properly account for linear correlations that arise from the discrete binning along each physical dimension (these capabilities reproduce and extend those of the earlier HIF code BPIC). The new diagnostics allow for the calculation of multi-dimensional maps of energy spread and temperature in 2-D axisymmetric or 3-D Cartesian space at selected times. The simulated beam-line was terminated at z = 3 m by a conducting plate, so as to approximately reproduce the experimental conditions at the entrance of the spectrometer that was used for mapping the longitudinal phase space. Snapshots of the beam projection and current, as well as the Marx waveform and history of beam kinetic energy collected at the end plate, are shown in Fig. 1. A two-dimensional axisymmetric map of energy spread from simulations of a typical NDCX-I configuration is shown in Fig. 2 (a). The energy spread starts at 0.1 eV at the source and rapidly rises to a few eV, then fluctuates between a fraction of an eV and tens of eV, ending near the exit in a range of a few eV at the outer edge of the beam to a few tens of eV near the axis. The higher value on-axis is associated with greater numerical noise there, due to the axisymmetric geometry of the calculation, resulting in poorer simulation-particle statistics at small radius. A scatter plot of the macroparticles kinetic energy (KE) versus radius (R) and longitudinal position (0.28 m energy spread is shown in Fig. 2 (b). As expected, there is a correlation of the kinetic energy with radius that is clearly visible at z = 2.8 m and vanishes at the metal plate at z = 3 m. More snapshots from simulations varying the time step, grid resolution and number of macroparticles are given in Appendix II. The macro-particles were collected at the exit plate and their kinetic energy history is plotted in Fig. 3 (left) and contrasted to an experimental measurement using a streak camera shown in Fig. 3. For some types of measurements, averaging over several pulses to improve signal-to-noise will contribute an additional spread that may not be present on any single beam pulse. The upper bound for the energy spread is in the range of a few 100 eV for the experiment while in the range of a few eV for the reported Warp simulations. The Marx voltage exhibits variations in the range of up to several hundreds of volts, playing a significant role in the experimentally measured energy spread, which may account for the difference between the experimental and the simulated bounds.
Windback seal design for gas compressors: a numerical and experimental study
Seals are considered one of the important flow elements of a turbomachinery device. Traditional labyrinth seals have proven their performance functionality by reducing leakage rates. Significant improvements on labyrinth seal functionality were obtained through altering the design geometry of labyrinth seals to prevent contamination across a seal and maintaining small leakage flowrates. This results in a windback seal that has only one tooth which continuously winds around the shaft like a screw thread. These seals are used in gas compressors to isolate the gas face seal from bearing oil. A purge gas is passed through the seal into the bearing housing. The helical design allows the seal to clear itself of any oil contamination. Windback seal performance is controlled through changing the seal geometry. A 2D graphical design tool for calculating the total and cavity leakage flowrates for windback seals is introduced. The effectiveness of the Fluent CFD (Computational Fluid Dynamics) commercial code to accurately predict the leakage rate for windback seals was evaluated. The objective is to determine if CFD simulations can be used along with a few experimental tests to study windback seals of this design with air as the working fluid. Comparison of measurement and predictions for a windback seal using the �?º-�?µ turbulence model with enhanced wall treatment functions show predictions and measurements comparing very well with a maximum difference of 5% for leakage rate. Similarly, the leakage rate of the tested smooth seal compares favorably with two dimensional CFD predictions, with a difference of 2%-11% and 8%-15% using laminar and �?º-�?µ turbulent flow models, respectively. The variation of leakage with shaft speed and pressure ratio across the seals is accurately predicted by the CFD simulations. Increasing the rotor speed to 15000 rpm increases the measured leakage flowrate for the windback seal by 2% at high differential pressure and 4.5% at low differential pressure, and decreases it by 10 % for the smooth seal. The effects of seal clearance, tooth pitch, cavity depth and the tooth number of starts on leakage flowrate, velocity and pressure distributions were studied numerically for three differential pressures and four rotor speeds.
Al-Ghasem, Adnan Mahmoud
Numerical and Experimental Study of Mixing Processes Associated with Hydrogen and High Hydrogen Content Fuels
As simulation capability improves exponentially with increasingly more cost effective CPUs and hardware, it can be used �routinely� for engineering applications. Many commercial products are available and they are marketed as increasingly powerful and easy to use. The question remains as to the overall accuracy of results obtained. To support the validation of the CFD, a hierarchical experiment was established in which the type of fuel injection (radial, axial) as well as level of swirl (non-swirling, swirling) could be systematically varied. The effort was limited to time efficient approaches (i.e., generally RANS approaches) although limited assessment of time resolved methods (i.e., unsteady RANS and LES) were considered. Careful measurements of the flowfield velocity and fuel concentration were made using both intrusive and non-intrusive methods. This database was then used as the basis for the assessment of the CFD approach. The numerical studies were carried out with a statistically based matrix. As a result, the effect of turbulence model, fuel type, axial plane, turbulent Schmidt number, and injection type could be studied using analysis of variance. The results for the non-swirling cases could be analyzed as planned, and demonstrate that turbulence model selection, turbulence Schmidt number, and the type of injection will strongly influence the agreement with measured values. Interestingly, the type of fuel used (either hydrogen or methane) has no influence on the accuracy of the simulations. For axial injection, the selection of proper turbulence Schmidt number is important, whereas for radial injection, the results are relatively insensitive to this parameter. In general, it was found that the nature of the flowfield influences the performance of the predictions. This result implies that it is difficult to establish a priori the �best� simulation approach to use. However, the insights from the relative orientation of the jet and flow do offer some guidance for which approach to take. Overall, the results underscore the importance of model �anchoring� (i.e., �tuning� the model to provide �reasonable� agreement with a well characterized geometry/flow). Finally, the results obtained have been carefully compiled into a standalone database following a standard format that is contained in an Appendix. This database is thus available for use by others for CFD modeling evaluations.
McDonell, Vincent; Hill, Scott; Akbari, Amin; McDonell, Vincent
Numerical modeling of species transport in turbulent flow and experimental study on aerosol sampling
Numerical simulations were performed to study the turbulent mixing of a scalar species in straight tube, single and double elbow flow configurations. Different Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) models were used to model the turbulence in the flow. Conventional and dynamic Smagorinsky sub-grid scale models were used for the LES simulations. Wall functions were used to resolve the near wall boundary layer. These simulations were run with both two-dimensional and three-dimensional geometries. The velocity and tracer gas concentration Coefficient of Variations were compared with experimental results. The results from the LES simulations compared better with experimental results than the results from the RANS simulations. The level of mixing downstream of a S-shaped double elbow was higher than either the single elbow or the U-shaped double elbow due to the presence of counter rotating vortices. Penetration of neutralized and non-neutralized aerosol particles through three different types of tubing was studied. The tubing used included standard PVC pipes, aluminum conduit and flexible vacuum hose. Penetration through the aluminum conduit was unaffected by the presence or absence of charge neutralization, whereas particle penetrations through the PVC pipe and the flexible hosing were affected by the amount of particle charge. The electric field in a space enclosed by a solid conductor is zero. Therefore charged particles within the conducting aluminum conduit do not experience any force due to ambient electric fields, whereas the charged particles within the non-conducting PVC pipe and flexible hose experience forces due to the ambient electric fields. This increases the deposition of charged particles compared to neutralized particles within the 1.5� PVC tube and 1.5� flexible hose. Deposition 2001a (McFarland et al. 2001) software was used to predict the penetration through transport lines. The prediction from the software compared well with experiments for all cases except when charged particles were transported through non-conducting materials. A Stairmand cyclone was designed for filtering out large particles at the entrance of the transport section.
Vijayaraghavan, Vishnu Karthik
Large-Scale Response of the Pacific Ocean Subarctic Front to Momentum Transfer: A Numerical Study
A numerical four-layer hydrodynamical model is implemented to investigate the role the atmosphere exerts on the dynamics of the subarctic front. While the effect of the westerly winds causes a southward shift of the front, the effect of a ...
Alejandro Camerlengo
Numerical methods for the estimation of multifractal singularity spectra on sampled data: a comparative study
Physical variables in scale invariant systems often show chaotic, turbulent-like behavior, commonly associated to the existence of an underlying fractal or multifractal structure. However, the assessment of multifractality over experimental, discretized ... Keywords: WTMM, fractals, multifractals, numerical methods, singularity analysis, wavelets
Antonio Turiel; Conrad J. P�rez-Vicente; Jacopo Grazzini
Numerical Studies of Collective Phenomena in Two-Dimensional Electron and Cold Atom Systems
Numerical calculations were carried out to investigate a number of outstanding questions in both two-dimensional electron and cold atom systems. These projects aimed to increase our understanding of the properties of and prospects for non-Abelian states in quantum Hall matter.
Rezayi, Edward
Mesoscale Momentum Budget in a Midlatitude Squall Line: A Numerical Case Study
A meso?-scale momentum budget and its effect on larger-scale mean flow in a midlatitude mesoscale convective system are investigated using a numerical simulation of an intense squall line that occurred during 10�11 June 1985 PRE-STORM. It is ...
Kun Gao; Da-Lin Zhang; Mitchell W. Moncrieff; Han-Ru Cho
Advanced Cell Development and Degradation Studies
The Idaho National Laboratory (INL) has been researching the application of solid-oxide electrolysis cells for large-scale hydrogen production from steam over a temperature range of 800 to 900�C. From 2003 � 2009, this work was sponsored by the DOE Nuclear Hydrogen Initiative (NHI). Starting in 2010, the HTE research program has been sponsored by the Next Generation Nuclear Plant (NGNP) program. HTSE research priorities in FY10 are centered on understanding and reducing cell and stack performance degradation to an acceptable level to advance the technology readiness level of HTSE and to justify further large-scale demonstration activities. This report provides a summary of our FY10 experimental program, which has been focused on advanced cell and stack development and degradation studies. Advanced cell and stack development activities are under way at five technology partners: MSRI, Versa Power, Ceramatec, NASA Glenn, and St. Gobain. Performance evaluation of the advanced technology cells and stacks has been performed by the technology partners, by MIT and the University of Connecticut and at the INL HTE Laboratory. Summaries of these development activities and test results are presented.
J. E. O' Brien; C. M. Stoots; J. S. Herring; R. C. O' Brien; K. G. Condie; M. Sohal; G. K. Housley; J. J. Hartvigsen; D. Larsen; G. Tao; B. Yildiz; V. Sharma; P. Singh; N. Petigny; T. L. Cable
Numerical Modeling Study and Assessment of PWR Fuel Rod and Assembly Distortion
Fuel assembly and rod distortion experienced in pressurized water reactors (PWRs) result in numerous operational challenges to plant operators such as mechanical interference between distorted assembly and control rods, difficulties in unloading and reloading cores during outages, and possibly anomalous fuel performance due to atypical water gaps. Therefore, an improved understanding of the various parameters contributing to distortion is important in order to manage or otherwise eliminate these ...
Interaction of Plasma Discharges with a Flame: Experimental and Numerical Study
This paper presents experimental results and numerical simulations of methane/air non-premixed flame under plasma assistance. Without plasma assistance, the flame blows off at a 28-30 m{center_dot}s{sup -1} bulk velocity (power around 3 kW). When the discharge is on, the flame can be maintained up to a bulk velocity of 53 m{center_dot}s{sup -1}(power around 6 kW), corresponding to +90% gain in power with only a few watt of plasma power. The plasma discharges present short duration current pulses (between 100 ns and 200 ns) and occur non-monotonically (delay between two pulses from 6x10{sup -5} s to 0.1 s). The probability density function of this occurrence is significantly influenced by the mass flow rate or the absence of flame, revealing the strong coupling of the plasma with hydrodynamic and combustion. For the numerical section of this work, we simulated the flame using a Computational Fluid Dynamics code based on Direct Numerical Simulation (direct solving of Navier-Stokes equations), and investigated the thermal and/or chemical effects of discharges on the flame stability.
Vincent-Randonnier, Axel [ONERA, French Aerospace Lab, Palaiseau, F-91761 (France); Teixeira, David [IFP, Rueil-Malmaison, F-92852 (France)
Numerical study of an electrostatic plasma sheath containing two species of charged dust particles
A multi-fluid model is used to study the dynamics of a dusty plasma sheath consists of electrons, ions, and two species of charged dust particles, i.e., nano-size and micron-size particles. It is found that, when the sheath is dominated by the nano-size dust grains, spatially periodic fluctuations are developed in the profiles of the sheath potential, and the number density and velocity of the plasma and dust particles. Due to inertial effects, the fluctuations in the parameters of the micron-size grains are much lower than those of the other parameters. The competition between the electric and ion drag forces plays the primary role in development of the fluctuations. The spatial period of the fluctuations is approximately a few Debye lengths and their amplitude depends on the plasma and dust parameters. The fluctuations are reduced by the increase in the radius, mass density, and Mach number of the nano-size particles, as well as the density and Mach number of the ions. But, they are enhanced by the increase in the plasma number density and the electron temperature. The sheath thickness demonstrates a non-monotonic behavior against variation of the nanoparticle parameters, i.e., it first decreases quickly, shows a minimum, and then increases. However, the sheath width always decreases with the plasma number density and ion Mach number, while grows linearly with the electron temperature.
Foroutan, G. [Physics Department, Faculty of Science, Sahand University of Technology, 51335-1996 Tabriz (Iran, Islamic Republic of); Akhoundi, A. [Nanostructure Material Research Center, Sahand University of Technology, 51335-1996 Tabriz (Iran, Islamic Republic of)
Preliminary Study on Sustainable Low-Carbon Development Towards...
Preliminary Study on Sustainable Low-Carbon Development Towards 2030 in Vietnam Jump to: navigation, search Name Preliminary Study on Sustainable Low-Carbon Development Towards...
Renewable Energy Project Case Studies: Tribal and Developer Perspectiv...
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Renewable Energy Project Case Studies: Tribal and Developer Perspectives Webinar Renewable Energy Project Case Studies: Tribal and Developer Perspectives Webinar October 30, 2013...
Mesoscale Numerical Weather Prediction Models Used in Support of Infrared Hyperspectral Measurement Simulation and Product Algorithm Development
A novel application of numerical weather prediction (NWP) models within an end-to-end processing system used to demonstrate advanced hyperspectral satellite technologies and instrument concepts is presented. As part of this system, sophisticated ...
Jason A. Otkin; Derek J. Posselt; Erik R. Olson; Hung-Lung Huang; James E. Davies; Jun Li; Christopher S. Velden
Numerical study of electron-leakage power loss in a tri-plate transmission line
Numerical simulations have been conducted using NRL's DIODE2D computer code to model the steady-state behavior of electron flow in a radial diode and in its adjacent tri-plate transmission line (TTL). Particular attention was paid to the magnitude of the electron current flowing from the cathode to the anode surface in the TTL. A quantitative value for this effective power loss is given. The electron current is restricted mainly to the transition region in the TTL into which there is seepage of the B/sub z/ that is imposed in the diode gap. This finding highlights the importance of that region to diode designers.
Barker, R.J.; Goldstein, S.A.
Contribution to the numerical study of turbulence in high intensity discharge lamps
We present in this paper a comparison between results obtained with a laminar and turbulent models for high-pressure mercury arc. The two models are based on the resolution of bidimensional time-dependent equations by a semi-implicit finite-element code. The numerical computation of turbulent model is solved with large eddy simulation model; this approach takes into account the various scales of turbulence by a filtering method on each scale. The results show the quantitative influence of turbulence on the flow fields and also the difference between laminar and turbulent effects on the dynamic thermal behaviour and on the characteristics of the discharge.
Kaziz, S.; Ben Ahmed, R.; Helali, H.; Gazzah, H.; Charrada, K. [Unite d'Etude des Milieux Ionises et Reactifs, IPEIM, 5019 route de Kairouan Monastir (Tunisia)
A Study on Experiment and Numerical Analysis for Disclosing Shell Wall Thinning of a Feedwater Heater
Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle - installed downstream of the high pressure turbine extraction steam line - inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes the comparisons between the numerical analysis results using the FLUENT code and the down scale experimental data in an effort to determine root causes of the shell wall thinning of the high pressure feedwater heaters. The numerical analysis and experimental data were also confirmed by actual wall thickness measured by an ultrasonic test. (authors)
Kyeong Mo, Hwang; Tae Eun, Jin [Korea Power Engineering Company, 360-9, Mabuk-dong, Kusong-Eup, Yongin-Shi (Korea, Republic of); Lee, Woo [Daeji Metal Co., LTD., 994-57, Dongchun-Dong, Yeunsu-Gu, Incheon Shi (Korea, Republic of); Kyung Hoon, Kim [Kyunghee University, 1, Seocheon-Ri, Gihung-Eup, Yongin-Shi (Korea, Republic of)
Seismic Response Of Masonry Plane Walls: A Numerical Study On Spandrel Strength
The paper reports the results of a numerical investigation on masonry walls subjected to in-plane seismic loads. This research aims to verify the formulae of shear and flexural strength of masonry spandrels which are given in the recent Italian Standards. Seismic pushover analyses have been carried out using finite element models of unreinforced walls and strengthened walls introducing reinforced concrete (RC) beams at the floor levels. Two typologies of walls have been considered distinguished for the height to length ratio h/l of the spandrels: a) short beams (h/l = 1.33) and b) slender beams (h/l = 0.5). Results obtained for the unreinforced and the strengthened walls are compared with equations for shear and flexural strength provided in Standards [1]. The numerical analyses show that the reliability of these equations is at least questionable especially for the prediction of the flexural strength. In the cases in which the axial force has not been determined by the structural analysis, Standards seems to overestimate the flexural strength of short spandrels both for the unreinforced and the strengthened wall.
Betti, Michele; Galano, Luciano; Vignoli, Andrea [Department of Civil and Environmental Engineering (DICeA) University of Florence, Via di S. Marta 3, I-50139, Florence (Italy)
Field and numerical studies of tracer gas transport and surface gas tranfer in laterally uniform, partially stratified estuaries
Techniques for determination of reaeration rates in natural waterbodies are reviewed. The tracer gas technique for reaeration rate determination offers many advantages over other existing methods and is widely used in rivers and streams. The tracer gas method seems to be the most promising of available techniques for estuarine reaeration rate determination. The two-dimensional late-rally averaged equations describing flow and transport in estuaries are derived and discussed. A laterally averaged numerical model of estaurine hydrodynamics and transport is modified so that tracer gas releases may be simulated. Field studies conducted as a part of the study are described. Two dye releases were made in the upper Houston Ship Channel; two dye tracer gas releases were later made in the same region. The data from these studies are presented and analyzed. Mechanical mixing by shipping traffic proved to be the predominant mixing mechanism and a hindrance to further studies at that site. An intensive field study was conducted in the Colorado River estuary. Field data included velocities, salinity profiles, water surface elevations, and dye concentration data from three dye releases. The data from this study are used to calibrate and test the numerical model of estuarine tracer gas transport.
Bales, J.D.
A 3-D numerical study of pinhole diffraction to predict the accuracy of EUV point diffraction interferometry
A 3-D electromagnetic field simulation is used to model the propagation of extreme ultraviolet (EUV), 13-nm, light through sub-1500 {Angstrom} dia pinholes in a highly absorptive medium. Deviations of the diffracted wavefront phase from an ideal sphere are studied within 0.1 numerical aperture, to predict the accuracy of EUV point diffraction interferometersused in at-wavelength testing of nearly diffraction-limited EUV optical systems. Aberration magnitudes are studied for various 3-D pinhole models, including cylindrical and conical pinhole bores.
Goldberg, K.A. [Lawrence Berkeley National Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Physics; Tejnil, E. [California Univ., Berkeley, CA (United States). Dept. of Electrical Engineering and Computer Sciences; Bokor, J. [Lawrence Berkeley National Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Electrical Engineering and Computer Sciences
Numerical study on optimal Stirling engine regenerator matrix designs taking into account the effects of matrix
-PUMP DEVELOPMENT AND POTENTIAL APPLICATION OF STIRLING-ENGINE TECHNOLOGY P. D. Fairchild Energy Division BASTER C DEVELOPMENT AND POTENTIAL APPLICATION OF STIRLING ENGINE TECHNOLOGY P. D. Fairchild Energy Division C. D. West Division with emphasis on the Stirling engine technology projects. This paper 1) reviews the major projects
A Numerical Study on Sea/Land Breezes as a Gravity Current: Kelvin�Helmholtz Billows and Inland Penetration of the Sea-Breeze Front
A two-dimensional, nonhydrostatic, compressible, and dry numerical model was developed. By using high spatial resolution and an appropriate turbulence model, fine structure and dynamics of the sea-breeze head were investigated.
Weiming Sha; Takeshi Kawamura; Hiromasa Ueda
Experimental and Numerical Study of Low-Pressure Hg-Ar Discharge at High Current Densities: For the Journal of Applied Physics
Experimental and numerical research on mercury low-pressure discharges have supported the development of fluorescent lighting technologies and made fundamental contributions to the understanding of low-pressure plasma physics. Numerical models of fluorescent lamps under "standard" operating conditions have reproduced the essential physical behavior of these discharges fairly well. However, recent developments in the lighting industry have led to the introduction of lamps operating at much higher current ...
A Numerical Study of Climatic Oscillations Using a Coupled Atmosphere�Ocean Primitive Equation Model
A coupled atmosphere-ocean primitive equation model is developed. It is a free-dimensional general circulation model, with two layers in the atmosphere and two layers in the ocean and includes solar radiation, longwave radiation, sensible heating,...
Xiong-Shan Chen
P1-21: Numerical Analysis and Experimental Study on Dry Friction ...
Development of Multi-modal 3D Characterization Systems to Quantify Grain ... P1 -04: 3D Microstructural Characterization of Uranium Oxide as a Surrogate ... P2- 27: Characterization of Carbonate Rocks through X-ray Microtomography.
The Mean Summertime Circulation along Australia's Southern Shelves: A Numerical Study
For the first time, a high-resolution regional model is developed for the slope and shelf circulation within the Great Australian Bight and for the Gulfs region of South Australia. The results indicate the extent, nature, and dynamical ...
John F. Middleton; Guennadi Platov
Numerical Study of Rarefied Hypersonic Flow Interacting With a Continuum Jet
An uncoupled CFD-DSMC technique is developed and applied to provide solutions for continuum jets interacting with rarefied external flows. The technique is based on a correlation of the appropriate Bird breakdown parameter for a transitional-rarefied ...
Glass Christopher E.
National Strategy Study on the Clean Development Mechanism in...
on the Clean Development Mechanism in Indonesia Jump to: navigation, search Name National Strategy Study on the Clean Development Mechanism in Indonesia AgencyCompany...
Influence of shear flow on vesicles near a wall: a numerical study
We describe the dynamics of three-dimensional fluid vesicles in steady shear flow in the vicinity of a wall. This is analyzed numerically at low Reynolds numbers using a boundary element method. The area-incompressible vesicle exhibits bending elasticity. Forces due to adhesion or gravity oppose the hydrodynamic lift force driving the vesicle away from a wall. We investigate three cases. First, a neutrally buoyant vesicle is placed in the vicinity of a wall which acts only as a geometrical constraint. We find that the lift velocity is linearly proportional to shear rate and decreases with increasing distance between the vesicle and the wall. Second, with a vesicle filled with a denser fluid, we find a stationary hovering state. We present an estimate of the viscous lift force which seems to agree with recent experiments of Lorz et al. [Europhys. Lett., vol. 51, 468 (2000)]. Third, if the wall exerts an additional adhesive force, we investigate the dynamical unbinding transition which occurs at an adhesion strength linearly proportional to the shear rate.
Sreejith Sukumaran; Udo Seifert
Room ventilation and its influence on the performance of fume cupboards: A parametric numerical study
The three-dimensional turbulent flow in a typical chemical laboratory containing two fume cupboards and furniture is investigated numerically in order to obtain detailed information needed for the improved design of ventilating systems for such rooms. The flow inside the two fume cupboards is simulated simultaneously with the room flow, and its dependence on the flow structure in the room is shown. The flow inside the cupboards and in the vicinity of their sash openings has been found to be essentially three-dimensional. Several room parameters are varied, and a quantitative evaluation of their influence on the flow, the comfort characteristics, and the ventilation efficiency is given. Additional ceiling-mounted openings, which extract room air outside the fume cupboards, can affect the capture efficiency of the cupboards, as well as the quality of the air in the room. It has been found also that small changes in the position of the radial inlet ceiling-mounted diffuser can influence the air quality of the room and at the same time the draught risk. These effects are shown for a given room arrangement. To accommodate the complex geometry, the elliptical nature of the mathematical problem, and the use of a turbulence model, a multigrid acceleration method with 245,000 control volumes is used, allowing CPU times on a workstation to become acceptable.
Denev, J.A.; Durst, F.; Mohr, B. [Friedrich Alexander Univ. Erlangen-Nuernberg, Erlangen (Germany)] [Friedrich Alexander Univ. Erlangen-Nuernberg, Erlangen (Germany)
A numerical study of convection in a layered porous medium heated from below
As part of the Magma Energy Project being pursued at Sandia National Laboratories, a drilling program has been initiated within the Long Valley caldera near Mammoth Lakes, California. Seismological evidence obtained in this region suggests the presence of a relatively shallow magma body. We have performed a numerical simulation for a simplified model of the Long Valley geothermal system in order to elucidate the nature of the large-scale thermal structure within the system and to assess implications for the drilling program. The two-dimensional model consists of three horizontal layers, the upper two of which are porous and saturated with a single phase fluid. The system is limited in horizontal extent and heated uniformly from below. An associated planar, natural convective flow is thus produced. The results of our simulation indicate the possibility of wide variations in vertical temperature profiles for the model system, depending on the location of the drilling operation. Thus it can be inferred that, during the early stages of drilling, the vertical temperature distribution is not a reliable indicator of the presence or absence of a magma body at depth. 14 refs., 5 figs., 4 tabs.
Hickox, C.E.; Chu, Tze Yao.
A new chemodynamical tool to study the evolution of galaxies in the local Universe: a quick and accurate numerical technique to compute gas cooling rate for any chemical composition
We have developed a quick and accurate numerical tool to compute gas cooling whichever its chemical composition.
Nicolas Champavert; Herv� Wozniak
ESMAP-Indonesia-Low Carbon Development Options Study | Open Energy
Low Carbon Development Options Study Low Carbon Development Options Study Jump to: navigation, search Name Indonesia-ESMAP Low Carbon Country Studies Program Agency/Company /Organization Energy Sector Management Assistance Program of the World Bank Partner United Kingdom Department for International Development Sector Energy, Land Focus Area Energy Efficiency, Forestry Topics Background analysis, GHG inventory, Low emission development planning, Market analysis, Policies/deployment programs Website http://www-wds.worldbank.org/e Country Indonesia South-Eastern Asia References World Bank, ESMAP - Low Carbon Growth Country Studies - Getting Started[1] Overview "The Indonesia's study aimed to evaluate and develop strategic options to mitigate climate change without compromising the country's development
The Extinction-to-Backscatter Ratio of Tropospheric Aerosol: A Numerical Study
An adequate estimation of the aerosol extinction-to-backscatter ratio S is important for solving the underdetermined single scattering lidar equation and for investigating the climate impact of aerosols. In this study, the extinction-to-...
J�rg Ackermann
A Numerical Study of Stratified Tidal Rectification over Finite-Amplitude Banks. Part I: Symmetric Banks
Tidal rectification over a two-dimensional finite-amplitude symmetrical bank is studied using the Blumberg and Mellor primitive equation coastal ocean circulation model (ECOM-si). In the homogeneous case, the nonlinear interaction of tidal ...
Changsheng Chen; Robert C. Beardsley
Tropical Ocean Decadal Variability and Resonance of Planetary Wave Basin Modes. Part II: Numerical Study
Oceanic response to stochastic wind forcing is studied in a tropical�extratropical basin using two shallow water models: a periodically forced model and a time-forward model. Consistent with theory, extratropical stochastic wind forces a decadal ...
Haijun Yang; Zhengyu Liu; Qiong Zhang
Numerical Model Studies of the Winter-Storm Response of the West Florida Shelf
The wintertime, wind-driven Ocean circulation on the West Florida Continental Shelf is studied within the framework of a linearized storm-surge model. The model bathymetry incorporates a realistic shelf, extending from New Orleans to the southern ...
Ya Hsueh; G. O. Marmorino; Linda L. Vansant
Numerical Studies of Major and Minor Stratospheric Warmings Caused by Orographic Forcing
A primitive equation spectral model using spherical harmonics is formulated to study dynamic interactions between the troposphere and stratosphere in association with sudden stratospheric warmings. Using sigma coordinates for five tropospheric ...
J. P. Koermer; A. Kasahara; S. K. Kao
Laboratory Studies and Numerical Simulations of Cloud Droplet Formation under Realistic Supersaturation Conditions
In this paper, a new device is introduced to study the formation and growth of cloud droplets under near-atmospheric supersaturations. The new device, called the Leipzig Aerosol Cloud Interaction Simulator (LACIS), is based on a laminar flow ...
F. Stratmann; A. Kiselev; S. Wurzler; M. Wendisch; J. Heintzenberg; R. J. Charlson; K. Diehl; H. Wex; S. Schmidt
A Numerical Study of Stratified Tidal Rectification over Finite-Amplitude Banks. Part II: Georges Bank
Tidal rectification over an idealized two-dimensional cross section of Georges Bank, which is a large, shallow, elongated submarine bank in the Gulf of Maine, is studied using a primitive equation coastal ocean circulation model. In the ...
Changsheng Chen; Robert C. Beardsley; Richard Limeburner
Numerical Studies of Cyclogenesis Events during the Second Intensive Observation Period (IOP-2) of GALE
A research version of the Navy Operational Regional Atmospheric Prediction System (NORAPS) is used to study cyclogenesis events during the second Intensive Observation Period of the Genesis of Atlantic Lows Experiment (GALE). From 1200 UTC 26 ...
Chi-Sann Liou; Carlyle H. Wash; Stacey M. Heikkinen; Russell L. Elsberry
Numerical Simulation of Squeeze Film Dampers and Study of the Effect of Central Groove on the Dynamic Pressure Distribution
Squeeze film dampers are used in the high speed turbo machinery industry and aerospace industries as a means to reduce vibration amplitude, to provide damping, to improve dynamic stability of the rotor bearing system and to isolate structural components. The effects of cavitation included in previous studies were not effective. The effect of different design parameters were not studied thoroughly as experimental investigation of squeeze film dampers is very expensive. Few of them used numerical investigation but the methods they used are either time consuming or complicated. The present study investigated the feasibility of applying a steady state solver, which is computationally less expensive, for analyzing flow field inside the squeeze film dampers. The behavior of dynamic pressure profiles at different operating conditions, and the effect of a central groove on dynamic pressure profiles were also studied. Simulation results of a 3D case which is similar to the one experimentally studied by Delgado were used to establish if the moving reference frame (MRF) model in Fluent 12.1 can be used. A steady state solver in an absolute frame of reference was used to produce whirling motion of the rotor in this study. The inlet pressure of 31kpa and the whirling speed of 50 and 100Hz were used as boundary conditions. The mixture model with three percent dissolved air in lubricant is used to model multiphase flow. Singhal cavitation model is used to model cavitation. The simulations (50,000 iterations) were run until steady state solutions were reached. The results closely agreed with those obtained experimentally by San Andr�s and Delgado. Numerical simulations of three-dimensional cases with an additional central groove on the squeeze film land were also performed to predict the effect of central groove on dynamic pressure profiles. Addition central groove reduces the pressures and forces generated by squeeze film damper.
Boppa, Praneetha
A Numerical Study of the Effect of a Mountain Range on a Landfalling Tropical Cyclone
A triply-nested, movable mesh model was used to study the effects of a mountain range on a landfalling tropical cyclone embedded in an easterly flow of 10 m s?1. The integration domain consisted of a 37� wide and 45� long channel, with an ...
Morris A. Bender; Robert E. Tuleya; Yoshio Kurihara
A Numerical Study of the Effect of Island Terrain on Tropical Cyclones
A triply nested, movable mesh model was used to study the behavior of tropical cyclones encountering island mountain ranges. The integration domain consisted of a 37� wide and 45� long channel, with an innermost mesh resolution of 1/6�. The ...
A Numerical Case Study on the Initiation of the Madden�Julian Oscillation
A mesoscale tropical channel model is used to study the long-standing problem of the initiation of the Madden�Julian oscillation (MJO). With initial and lateral boundary conditions provided by a global reanalysis, this model is able to reproduce ...
Pallav Ray; Chidong Zhang; Jim Dudhia; Shuyi S. Chen
A Multiscale Numerical Study of Hurricane Andrew (1992). Part II: Kinematics and Inner-Core Structures
Despite considerable research, understanding of the temporal evolution of the inner-core structures of hurricanes is very limited owing to the lack of continuous high-resolution observational data of a storm. In this study, the results of a 72-h ...
Yubao Liu; Da-Lin Zhang; M. K. Yau
A Comparative Study of Numerical Advection Schemes Featuring a One-Step Modified WKL Algorithm
A fourth-order Crowley-type advection scheme based on the multistep Warming-Kutler-Lomax (WKL) scheme is proposed in this study. This scheme utilizes a free parameter to minimize dispersion and dissipation and can be used to represent the ...
Ching-Yuang Huang; Sethu Raman
A Numerical Study to Investigate the Relationship between Moisture Convergence Patterns and Orography in Central Mexico
This study examines small-scale orographic effects on atmospheric moisture convergence at the ridge�valley scale in the Grande de Santiago River basin in central Mexico during a major monsoon storm on 13�14 August 1999. The simulation was ...
S. Bhushan; A. P. Barros
A Numerical Study on Tropical Cyclone Intensification. Part I: Beta Effect and Mean Flow Effect
The effect of planetary vorticity gradient (beta) and the presence of a uniform mean flow on the intensification of tropical cyclones are studied using a limited-area primitive equation model. The most intense storm evolves on a constant-f plane ...
Melinda S. Peng; Bao-Fong Jeng; R. T. Williams
Study of the collision of one rapid sphere on 3D packings: Experimental and numerical results
We report on experimental studies of the collision process between an incident bead and a three-dimensional packing of mono-size beads. The understanding of such a process and the resulting ejection of grains is, in particular, crucial to describe aeolian ... Keywords: DEM modelisation, Granular transport, Saltation
L. Oger; M. Ammi; A. Valance; D. Beladjine
Numerical Study of Geometry and Rotation Dependence on the Flow in Labyrinth Seals
A computational study was conducted on the flow, both compressible and incompressible, in a labyrinth seal at various geometries and rotation rates. The computations were performed using the commercial software Fluent� which solves the k-? model to predict the flow field in the seal. Various clearance-pitch ratios were used to study the effect of clearance on the flow. The aspect ratio, which is defined as the pitch-height ratio was varied to study the influence of the depth of the cavity on the flow as a whole. These studies span a range of Taylor's number that is defined accordingly, while fixing the Reynolds number at 1000. The effects of clearance, aspect ratio and rotational rates are studied using carry-over coefficient and discharge coefficient. It is observed that a secondary recirculation zone (SRZ) occurs inside a seal cavity at above certain Taylor's number. This significantly changes the flow field in the seal and the cavity which results an increases in pressure drop across the seal for a given flow boundary condition. This formation of SRZ's is more evident in incompressible flow and occur at prohibitively high rotational speeds in case of air (compressible flow). It is also observed that flow with teeth on rotor are characterized by SRZ's while it's not case with teeth on stator. A flow map which shows the onset and presence of SRZ's is shown. The ratio of tangential velocity of the shaft to the average of the swirl velocity in a cavity at various geometries of the cavities are presented. They seem to be decreasing with decreasing depth and follow a linear pattern with the aspect ratios of the cavity.
Yamsani, Vamshi Krishna
A Numerical Sensitivity Study on the Impact of Soil Moisture on Convection-Related Parameters and Convective Precipitation over Complex Terrain
The impact of soil moisture on convection-related parameters and convective precipitation over complex terrain is studied by numerical experiments using the nonhydrostatic Consortium for Small-Scale Modeling (COSMO) model. For 1 day of the ...
Christian Barthlott; Norbert Kalthoff
A numerical study of free convective heat transfer in a double-glazed window with a between-pane Venetian blind.
??The free convective heat transfer in a double-glazed window with a between-pane Venetian blind has been studied numerically. The model geometry consists of a two-dimensional� (more)
Avedissian, Tony
A numerical study comparing the combustion and emission characteristics of biodiesel with petrodiesel.
Combustion and emission characteristics of compression ignition engines strongly depend upon inner-nozzle flow and spray behavior. These processes control the fuel-air mixing, which in turn is critical for the combustion process. Previous studies by us highlighted the differences in the physical and chemical properties of petrodiesel and biodiesel, which significantly altered the inner-nozzle flow and spray structure. The current study is another step in this direction to gain a fundamental understanding on the influence of fuel properties on the combustion and emission characteristics of the compression ignition engine. n-Heptane and methyl butanoate were selected as surrogates for diesel and biodiesel fuels, respectively, because the chemical kinetic pathways were well-understood. Liquid length and flame lift-off length for diesel and biodiesel fuels were validated against data available in the literature. Liquid lengths were always higher for biodiesel because of its higher heat of vaporization, which resulted in increased interplay between spray and combustion processes under all conditions investigated. Ambient air entrainment was also lower for biodiesel mainly because of slower atomization and breakup. The mechanism for flame stabilization is further analyzed by estimating the turbulent burning velocity for both of the fuels. This analysis revealed that neither flame propagation nor isolated ignition kernels upstream and detached from high-temperature regions can be the mechanism for flame stabilization. Flame propagation speeds were observed to be similar for both fuels. Biodiesel predicted lower soot concentrations, which were also reflected in reduced C{sub 2}H{sub 2} mole fractions. Although prompt NO{sub x} was higher for biodiesel, total NO{sub x} was lower because of reduced thermal NO{sub x}. The ignition delay and NO{sub x} emissions predicted by these simulations do not agree with trends reported in the literature; hence, this study highlights the need for better fuel surrogates for diesel and biodiesel fuels.
Som, S.; Longman, D. (Energy Systems)
Numerical study of roughness distributions in nonlinear models of interface growth
We analyze the shapes of roughness distributions of discrete models in the Kardar, Parisi and Zhang (KPZ) and in the Villain, Lai and Das Sarma (VLDS) classes of interface growth, in one and two dimensions. Three KPZ models in d=2 confirm the expected scaling of the distribution and show a stretched exponential tail approximately as exp[-x^(0.8)], with a significant asymmetry near the maximum. Conserved restricted solid-on-solid models belonging to the VLDS class were simulated in d=1 and d=2. The tail in d=1 has the form exp(-x^2) and, in d=2, has a simple exponential decay, but is quantitatively different from the distribution of the linear fourth-order (Mullins-Herring) theory. It is not possible to fit any of the above distributions to those of 1/f^\\alpha noise interfaces, in contrast with recently studied models with depinning transitions.
Fabio D. A. Aar�o Reis
Numerical Study of Gamma-Ray Burst Jet Formation in Collapsars
Two-dimensional MHD simulations are performed using the ZEUS-2D code to investigate the dynamics of a collapsar that generates a GRB jet, taking account of realistic equation of state, neutrino cooling and heating processes, magnetic fields, and gravitational force from the central black hole and self-gravity. It is found that neutrino heating processes are not efficient enough to launch a jet in this study. It is also found that a jet is launched mainly by B{sub {phi}} fields that are amplified by the winding-up effect. However, since the ratio of total energy relative to the rest-mass energy in the jet is not as high as several hundred, we conclude that the jets seen in this study are not GRB jets. This result suggests that general relativistic effects will be important to generating a GRB jet. Also, the accretion disk with magnetic fields may still play an important role in launching a GRB jet, although a simulation for much longer physical time ({approx}10-100 s) is required to confirm this effect. It is shown that a considerable amount of {sup 56}Ni is synthesized in the accretion disk. Thus, there will be a possibility for the accretion disk to supply the sufficient amount of {sup 56}Ni required to explain the luminosity of a hypernova. Also, it is shown that neutron-rich matter due to electron captures with high entropy per baryon is ejected along the polar axis. Thus, there will be a possibility that r-process nucleosynthesis occurs at such a region. Finally, many neutrons will be ejected from the jet, which suggests that signals from the neutron decays may be observed as the delayed bump of the light curve of the afterglow or gamma rays.
Nagataki, S.; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park; Takahashi, R.; /Tokyo U.; Mizuta, A.; Takiwaki, T.; /Garching, Max Planck Inst. /Tokyo U.
A Study of Software Development for High Performance Computing
A Study of Software Development for High Performance Computing Manish Parashar, Salim Hariri Parallel Distributed Systems, 1994 Abstract Software development in a High Performance Computing (HPC. The objective of this paper is to study the software development process in a high performance computing
Parashar, Manish
Numerical studies of fluid-rock interactions in EnhancedGeothermal Systems (EGS) with CO2 as working fluid
There is growing interest in the novel concept of operating Enhanced Geothermal Systems (EGS) with CO{sub 2} instead of water as heat transmission fluid. Initial studies have suggested that CO{sub 2} will achieve larger rates of heat extraction, and can offer geologic storage of carbon as an ancillary benefit. Fluid-rock interactions in EGS operated with CO{sub 2} are expected to be vastly different in zones with an aqueous phase present, as compared to the central reservoir zone with anhydrous supercritical CO{sub 2}. Our numerical simulations of chemically reactive transport show a combination of mineral dissolution and precipitation effects in the peripheral zone of the systems. These could impact reservoir growth and longevity, with important ramifications for sustaining energy recovery, for estimating CO{sub 2} loss rates, and for figuring tradeoffs between power generation and geologic storage of CO{sub 2}.
Xu, Tianfu; Pruess, Karsten; Apps, John
The Savannah River National Laboratory (SRNL) was requested to develop a bench scale test facility, using a mixer, transfer pump, and transfer line to determine the impact of conveying the grout through the transfer lines to the vault on grout properties. Bench scale testing focused on the effect the transfer line has on the rheological property of the grout as it was processed through the transfer line. Rheological and other physical properties of grout samples were obtained prior to and after pumping through a transfer line. The Bench Scale Mixing Rig (BSMR) consisted of two mixing tanks, grout feed tank, transfer pump and transfer hose. The mixing tanks were used to batch the grout which was then transferred into the grout feed tank. The contents of the feed tank were then pumped through the transfer line (hose) using a progressive cavity pump. The grout flow rate and pump discharge pressure were monitored. Four sampling stations were located along the length of the transfer line at the 5, 105 and 205 feet past the transfer pump and at 305 feet, the discharge of the hose. Scaling between the full scale piping at Saltstone to bench scale testing at SRNL was performed by maintaining the same shear rate and total shear at the wall of the transfer line. The results of scaling down resulted in a shorter transfer line, a lower average velocity, the same transfer time and similar pressure drops. The condition of flow in the bench scale transfer line is laminar. The flow in the full scale pipe is in the transition region, but is more laminar than turbulent. The resulting plug in laminar flow in the bench scale results in a region of no-mixing. Hence mixing, or shearing, at the bench scale should be less than that observed in the full scale, where this plug is non existent due to the turbulent flow. The bench scale tests should be considered to be conservative due to the highly laminar condition of flow that exists. Two BSMR runs were performed. In both cases, wall shearing was shown to reduce the rheological properties of the grout as it was processed through the transfer line. Samples taken at the static feed tank showed that gelling impacted the rheological properties of the grout before it was fed into the pump and transfer line. A comparison of the rheological properties of samples taken at the feed tank and transfer line discharge indicated shearing of the grout was occurring in the transfer line. Bench scale testing of different mixing methods with three different salt solutions showed that method of mixing influences the rheological properties of the grouts. The paddle blade mixing method of the salt solution used for the BMSR testing provided comparable rheological properties of the grout prepared in the BMSR after 14 minutes of processing, B3. The paddle blade mixing method can be used to represent BMSR results and mixing time can be adjusted to represent larger scale mixing.
Cozzi, A.; Hansen, E.
Development and Tropical Transition of an Alpine Lee Cyclone. Part I: Case Analysis and Evaluation of Numerical Guidance
The development and tropical transition (TT) of a subsynoptic-scale cyclone in the Gulf of Genoa during the Mesoscale Alpine Project (MAP) demonstration of probabilistic hydrological and atmospheric simulation of flood events in the alpine region ...
Ron McTaggart-Cowan; Thomas J. Galarneau Jr.; Lance F. Bosart; Jason A. Milbrandt
An ethnographic case study of transformative learning in leadership development.
??This qualitative study investigated how transformative learning and membership in a community of practice influenced leadership development. It sought a phenomenological understanding of how participants� (more)
Powell, Linda Chastain
Studying Code Development for High Performance Computing: The HPCS Program
Studying Code Development for High Performance Computing: The HPCS Program Jeff Carver1 , Sima at measuring the development time for programs written for high performance computers (HPC). Our goal. Introduction The development of High-Performance Computing (HPC) programs (codes) is crucial to progress
Basili, Victor R.
World Business Council for Sustainable Development-Case Studies | Open
Development-Case Studies Development-Case Studies Jump to: navigation, search Name World Business Council for Sustainable Development-Case Studies Agency/Company /Organization World Business Council for Sustainable Development Sector Energy, Land Focus Area Energy Efficiency, Renewable Energy, Buildings, Industry Topics Implementation Resource Type Lessons learned/best practices Website http://www.wbcsd.org/templates References Case Studies[1] Background "The WBCSD seeks to illustrate how companies work independently, or with different stakeholders, to integrate the challenge of sustainable development into their business activities. The value of sharing these experiences lies in their ability to further the business case for sustainable development by supporting the design of effective processes to
A numerical study of transient ignition and flame characteristics of diluted hydrogen versus heated air in counterflow
Combined experimental and numerical studies of the transient response of ignition to strained flows require a well-characterized ignition trigger. Laser deposition of a small radical pool provides a reliable method for initiating ignition of mixtures that are near the ignition limit. Two-dimensional direct numerical simulations are used to quantify the sensitivity of ignition kernel formation and subsequent edge-flame propagation to the oxidizer temperature and the initial width and amplitude of O-atom deposition used to trigger ignition in an axisymmetric counterflow of heated air versus ambient hydrogen/nitrogen. The ignition delay and super-equilibrium OH concentration in the nascent ignition kernel are highly sensitive to variations in these initial conditions. The ignition delay decreases as the amplitude of the initial O-atom deposition increases. The spatial distribution and the magnitude of the OH overshoot are governed by multi-dimensional effects. The degree of OH overshoot near the burner centerline increases as the diameter of the initial O-atom deposition region decreases. This result is attributed to preferential diffusion of hydrogen in the highly curved leading portion of the edge flame that is established following thermal runaway. The edge-flame speed and OH overshoot at the leading edge of the edge flame are relatively insensitive to variations in the initial conditions of the ignition. The steady edge-flame speed is approximately twice the corresponding laminar flame speed. The rate at which the edge flame approaches its steady state is insensitive to the initial conditions and depends solely on the diffusion time scale at the edge flame. The edge flame is curved toward the heated oxidizer stream as a result of differences in the chemical kinetics between the leading edge and the trailing diffusion flame. The structure of the highly diluted diffusion flame considered in this study corresponds to Linan's 'premixed flame regime' in which only the oxidizer leaks through the reaction zone such that the flame is located at fuel lean rather than stoichiometric mixture fraction conditions. (author)
Yoo, Chun Sang; Chen, Jacqueline H. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969 (United States); Frank, Jonathan H.
Yoo, Chun Sang; Chen, Jacqueline H.; Frank, Jonathan H. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969 (United States)
A numerical study of transient ignition and flame characteristics of diluted hydrogen versus heated air in counterflow.
Combined experimental and numerical studies of the transient response of ignition to strained flows require a well-characterized ignition trigger. Laser deposition of a small radical pool provides a reliable method for initiating ignition of mixtures that are near the ignition limit. Two-dimensional direct numerical simulations are used to quantify the sensitivity of ignition kernel formation and subsequent edge-flame propagation to the oxidizer temperature and the initial width and amplitude of O-atom deposition used to trigger ignition in an axisymmetric counterflow of heated air versus ambient hydrogen/nitrogen. The ignition delay and super-equilibrium OH concentration in the nascent ignition kernel are highly sensitive to variations in these initial conditions. The ignition delay decreases as the amplitude of the initial O-atom deposition increases. The spatial distribution and the magnitude of the OH overshoot are governed by multi-dimensional effects. The degree of OH overshoot near the burner centerline increases as the diameter of the initial O-atom deposition region decreases. This result is attributed to preferential diffusion of hydrogen in the highly curved leading portion of the edge flame that is established following thermal runaway. The edge-flame speed and OH overshoot at the leading edge of the edge flame are relatively insensitive to variations in the initial conditions of the ignition. The steady edge-flame speed is approximately twice the corresponding laminar flame speed. The rate at which the edge flame approaches its steady state is insensitive to the initial conditions and depends solely on the diffusion time scale at the edge flame. The edge flame is curved toward the heated oxidizer stream as a result of differences in the chemical kinetics between the leading edge and the trailing diffusion flame. The structure of the highly diluted diffusion flame considered in this study corresponds to Linan's 'premixed flame regime' in which only the oxidizer leaks through the reaction zone such that the flame is located at fuel lean rather than stoichiometric mixture fraction conditions.
Yoo, Chun Sang; Chen, Jacqueline H.; Frank, Jonathan H.
India Sectoral Study on Climate and Refrigeration Technology in Developing
India Sectoral Study on Climate and Refrigeration Technology in Developing India Sectoral Study on Climate and Refrigeration Technology in Developing Countries and the Development of Methods and Instruments for Identifying Reduction Potential and Implementing NAMAs Jump to: navigation, search Name India-Sectoral Study on Climate and Refrigeration Technology in Developing Countries and the Development of Methods and Instruments for Identifying Reduction Potential and Implementing NAMAs Agency/Company /Organization Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH Sector Climate Focus Area Renewable Energy, Greenhouse Gas Topics Low emission development planning, -LEDS, -NAMA, Market analysis Website http://www.giz.de/en/ Program Start 2010 Program End 2012 Country India Southern Asia References Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ)[1]
Mexico Sectoral Study on Climate and Refrigeration Technology in Developing
Mexico Sectoral Study on Climate and Refrigeration Technology in Developing Mexico Sectoral Study on Climate and Refrigeration Technology in Developing Countries and the Development of Methods and Instruments for Identifying Reduction Potential and Implementing NAMAs Jump to: navigation, search Name Mexico-Sectoral Study on Climate and Refrigeration Technology in Developing Countries and the Development of Methods and Instruments for Identifying Reduction Potential and Implementing NAMAs Agency/Company /Organization Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH Sector Climate Focus Area Renewable Energy, Greenhouse Gas Topics Low emission development planning, -LEDS, -NAMA, Market analysis Website http://www.giz.de/en/ Program Start 2010 Program End 2012 Country Mexico Central America References Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ)[1]
Sectoral Study on Climate and Refrigeration Technology in Developing
Study on Climate and Refrigeration Technology in Developing Study on Climate and Refrigeration Technology in Developing Countries and the Development of Methods and Instruments for Identifying Reduction Potential and Implementing NAMAs Jump to: navigation, search Name Sectoral Study on Climate and Refrigeration Technology in Developing Countries and the Development of Methods and Instruments for Identifying Reduction Potential and Implementing NAMAs Agency/Company /Organization Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH Sector Climate Focus Area Renewable Energy, Greenhouse Gas Topics Low emission development planning, -LEDS, -NAMA, Market analysis Website http://www.giz.de/en/ Program Start 2010 Program End 2012 Country India, Mexico, South Africa, Thailand Southern Asia, Central America, Southern Africa, South-Eastern Asia
Mixture Preparation and Nitric Oxide Formation in a GDI Engine studied by Combined Laser Diagnostics and Numerical Modeling
Through the combination of advanced imaging laser diagnostics with multi-dimensional computer models, a new understanding of the performance of direct-injection gasoline engines is pursuit. The work focuses on the fuel injection process, the breakup of the liquid into a fine spray and the mixing of the fuel with the in-cylinder gases. Non-intrusive laser diagnostics will be used to measure the spatial distribution of droplets and vaporized fuel with very high temporal resolution. These data along with temperature measurements will be used to validate a new spray breakup model for gasoline direct-injection. Experimental data on near wall fuel distributions will be used for comparison with a model that predicts the spray-wall interaction and the dynamics of the liquid film on the surface. Quantitative measurements of local nitric oxide concentrations inside the combustion chamber will provide a critical test for a numerical simulation of the nitric oxide formation process. This model is based on a modified flamelet approach and will be used to study the effects of exhaust gas recirculation.
Volker Sick; Dennis N. Assanis
Numerical overcooling in shocks
We present a study of cooling in radiative shocks simulated with smoothed particle hydrodynamics (SPH) and adaptive mesh refinement codes. We obtain a similarity solution for a shock-tube problem in the presence of radiative cooling, and test how well the solution is reproduced in Gadget and Flash. Shock broadening governed by the details of the numerical scheme (artificial viscosity or Riemann solvers) leads to potentially significant overcooling in both codes. We interpret our findings in terms of a resolution criterion, and apply it to realistic simulations of cosmological accretion shocks onto galaxy haloes, cold accretion and thermal feedback from supernovae or active galactic nuclei. To avoid numerical overcooling of accretion shocks onto haloes that should develop a hot corona requires a particle or cell mass resolution of 10^6 M_sun, which is within reach of current state-of-the-art simulations. At this mass resolution, thermal feedback in the interstellar medium of a galaxy requires temperatures of s...
Creasey, Peter; Bower, Richard G; Lacey, Cedric G
A Numerical Study of a Mesoscale Convective System during TOGA COARE. Part I: Model Description and Verification
A 16-h numerical simulation of the growing and mature stages of the 15 December 1992 Tropical Ocean Global Atmosphere Coupled Ocean�Atmosphere Response Experiment (TOGA COARE) mesoscale convective system (MCS) is performed to demonstrate the ...
Collision Efficiencies of Ice Crystals at Low�Intermediate Reynolds Numbers Colliding with Supercooled Cloud Droplets: A Numerical Study
The efficiencies with which ice crystals at low�intermediate Reynolds numbers collide with supercooled cloud droplets are determined numerically. Three ice crystal habits are considered here: hexagonal ice plates, broad-branch crystals, and ...
Pao K. Wang; Wusheng Ji
Mesoscale Numerical Study of Two Cases of Long-Lived Quasi-Stationary Convective Systems over Eastern Spain
A set of mesoscale numerical simulations using the Pennsylvania State University�National Center for Atmospheric Research model is used to investigate two cases of extreme precipitation over eastern Spain. Both cases (3�4 November 1987 and 20 ...
R. Romero; C. A. Doswell III; C. Ramis
A numerical study of flow-structure interactions with application to flow past a pair of cylinders
Flow-structure interaction is a generic problem for many engineering applications, such as flow--induced oscillations of marine risers and cables. In this thesis a Direct Numerical Simulation (DNS) approach based on ...
Papaioannou, Georgios (Georgios Vasilios), 1975-
Numerical Study of Some Unstably Stratified Boundary-Layer Flows over a Valley at Moderate Richardson Number
A two-dimensional numerical model is utilized to investigate steady-state, three-dimensional turbulent flow over a valley under unstable thermal stratifications. An eddy viscosity turbulence model is employed, in which the mixing length is a ...
J. D. Carlson; M. R. Foster
A Numerical Study of Inversion-Layer Breakup and the Effects of Topographic Shading in Idealized Valleys
Numerical simulations of inversion-layer breakup in idealized steep valleys are performed using the Advanced Regional Prediction System (ARPS) to investigate the effects of valley width and depth, and topographic shade. Simulations of the diurnal ...
Augustin Colette; Fotini Katopodes Chow; Robert L. Street
The Sensitivity of Numerical Forecasts to Convective Parameterization: A Case Study of the 17 February 2004 East Coast Cyclone
The sensitivity of numerical model forecasts of coastal cyclogenesis and frontogenesis to the choice of model cumulus parameterization (CP) scheme is examined for the 17 February 2004 southeastern U.S. winter weather event. This event featured a ...
Kelly M. Mahoney; Gary M. Lackmann
Numerical Simulations of the Formation of Hurricane Gabrielle (2001)
This study examines the formation of Hurricane Gabrielle (2001), focusing on whether an initial disturbance and vertical wind shear were favorable for development. This examination is performed by running numerical experiments using the fifth-...
K. D. Musgrave; C. A. Davis; M. T. Montgomery
History of Numerical Weather Prediction at the National Meteorological Center
The first modern numerical weather prediction (NWP) models were developed for the computer that was announced in 1932 at the Institute for Advanced Study, in Princeton, New Jersey. Within 3 yr three agencies of the United States Government ...
Frederick G. Shuman
The Impact of Assimilating Satellite-Derived Precipitation Rates on Numerical Simulations of the ERICA IOP 4 Cyclone
The present study uses a regional-scale numerical model to test the impact of dynamically assimilating, satellite-derived precipitation rates on the numerical simulations of one of the deepest extratropical cyclones to develop south of 40�N in ...
John Manobianco; Steven Koch; V. Mohan Karyampudi; Andrew J. Negri
General Renewable Energy-Market Development Studies | Open Energy
General Renewable Energy-Market Development Studies General Renewable Energy-Market Development Studies Jump to: navigation, search Tool Summary Name: General Renewable Energy-Market Development Studies Agency/Company /Organization: World Bank Sector: Energy Topics: Finance, Market analysis, Policies/deployment programs, Co-benefits assessment Website: web.worldbank.org/WBSITE/EXTERNAL/TOPICS/EXTENERGY2/EXTRENENERGYTK/0,, Country: China, Mexico Eastern Asia, Central America References: General Renewable Energy-Market Development Studies[1] Resources Energy-policy Framework Conditions for Electricity Markets and Renewable Energies: 21 Country Analyses, TERNA Wind Energy Programme, GTZ Global Renewable Energy Markets and Policies, Eric Martinot, University of Maryland, School of Public Affairs The Potentials of Renewable Energy, Thematic Background Paper,
Role of Aramco in Saudi Arabian development: a case study of dependent development
The primary purpose of this study is to evaluate whether the Kingdom of Saudi Arabia has proceeded along the path toward development while in a dependent relationship with the Arabian American Oil Company, Aramco. Development in a given country is defined as the process by which the living standards of the people who live in that country are raised. That process includes the development of physical and human infrastructure, economic growth, distribution of resources, and the maturation of society (including its ability to weather crisis, whether it be social or economic). Though it is by no means exhaustive on the subject of development in Saudi Arabia, this study focuses on Aramco's involvement in the socio-economic elements of development in Saudi Arabia, as these are the direct impacts of development upon which the Saudi five-year development plans focus. Employing the theoretical framework of dependent development as adapted by Timothy Luke to the OPEC countries' development experience in the international energy regime, this study serves in part as an in-depth case study of Luke's thesis.
Rawls, L.W.
Renewable Energy Project Case Studies: Tribal and Developer Perspectives
Project Case Studies: Tribal and Developer Project Case Studies: Tribal and Developer Perspectives Webinar Renewable Energy Project Case Studies: Tribal and Developer Perspectives Webinar October 30, 2013 11:00AM MDT Webinar The U.S. Department of Energy (DOE) Office of Indian Energy Policy and Programs, Office of Energy Efficiency and Renewable Energy Tribal Energy Program, and Western Area Power Administration are pleased to continue their sponsorship of the Tribal Renewable Energy Webinar Series. Attend this webinar to hear how Tribes have successfully implemented renewable energy projects using innovative programs and practices, and how those can be applied to your project. You'll get perspectives from both Tribes and the developer from two speakers: David Nahai of David Nahai Consulting Services will talk about his
An Observational and Numerical Study of an Intense Landfalling Cold Front along the Northwest Coast of the United States during COAST IOP 2
This paper presents an observational and numerical study of an intense wintertime cold front that made landfall along the northwest coast of the United States during IOP 2 (3�4 Dec 1993) of the Coastal Observation and Simulation with Topography ...
Fang-Ching Chien; Clifford F. Mass; Paul J. Neiman
Based on detailed steady-state system and component modeling, we developed a rooftop unit system design, which is able to achieve IEER (Integrated Energy Efficiency Ratio) higher than 20. We modeled fin-&-tube and micro-channel heat exchangers using segment-to-segment approach, and use ARI 10-coefficient compressor map to simulate compressor performance. The system modeling is based on a component-based modeling approach, which facilitates flexible simulation of complicated system configurations. Starting with a baseline system having IEER of 16.6, we extensively investigated numerous technical options, i.e. varying compressor sizes, heat exchanger fin densities, fin-&-tube or micro-channel heat exchanger, suction line heat exchanger, desiccant wheel, tandem compressor, variable-speed compressor, and condenser evaporative pre-cooling; and developed an innovative system configuration combining a tandem compression system with a variable-speed compression system. The combined system can achieve high IEER as well as process the outdoor ventilation air over an extensive range. We successfully evaluated the design concept for a 20-ton unit as well as a 10-ton unit. All the selected components are readily accessible on the market, and we validated the performance predictions against existing RTU products at the rating condition. This paper illustrates a potentially cost-effective high IEER RTU design.
Shen, Bo [ORNL; Rice, C Keith [ORNL; Vineyard, Edward [Oak Ridge National Laboratory (ORNL)
Incorporating UCD into the software development lifecycle: a case study
This case study addresses how we applied user centered design (UCD) to the software development lifecycle for the new City of Austin Utilities Online Customer Care website. The case study focuses on the use of personas, prototypes, and user testing, ... Keywords: personas, prototypes, simulations, ucd, usability, user centered design, user experience
Andy Switzky
Study about numerical relay SEL-387 for overcurrent and differential protections of 110/20 kV transformers
Nowadays, the main problems of the relay protections result from the fact that in the modern electric systems the performances imposed to the protections operation became very severe, enhancing the difficulty in their simultaneous satisfaction. In these ... Keywords: differential protection, numerical protection relay, overcurrent protection, transformer
Angela Iagar; Gabriel Nicolae Popa; Corina Maria Dinis; Gheorghe Moraru
Trade Study for Integrating Numerous SECA SOFC Modules Burak Ozpineci (Primary Contact), Donald J Adams, Leon M. Tolbert
.S. Department of Energy's Solid-State Energy Conversion Alliance (SECA) program is targeting solid oxide fuel of the complete system are still functioning), energy conversion efficiency, and ease of mass customization selected for integrating numerous fuel cells are series configuration, dc-link configuration, high
A numerical study of steady-state vortex configurations and vortex pinning in type-II superconductors
In part I, a numerical study of the mixed states in a mesoscopic type-II superconducting cylinder is described. Steady-state configurations and transient behavior of the magnetic vortices for various values of the applied magnetic field H are presented. Transitions between different multi-vortex states as H is changed is demonstrated by abrupt changes in vortex configurations and jumps in the B vs H plot. An efficient scheme to determine the equilibrium vortex configuration in a mesoscopic system at any given applied field, not limited to the symmetry of the system, is devised and demonstrated. In part II, a superconducting thin film is subject to a non-uniform magnetic field from a vertical magnetic dipole, consisting of two magnetic monopoles of opposite charges. For a film with constant thickness and with no pins, it has been found that the film carries two pairs of vortex-antivortex in the steady state in the imposed flux range of 2.15 < (Phi)+ < 2.90 (in units of flux quantum) and no vortex at all for (Phi)+ <= 2.15. Transitions from a superconducting state with 3 pairs of vortex-antivortex to one with 2 pairs, where a pair of vortex-antivortex annihilates, have been observed in the pseudo-time sequence. With a perturbation with antidots (holes), vortexantivortex pair has been created for lower magnetic fluxes down to (Phi)+ = 1.3. In the sample of size 16(Xi) x 16(Xi), the attraction force between the vortex and antivortex always dominates over the pinning force, so that they eventually come out of pins, move toward each other, and annihilate each other. The annihilation rate, measured with time taken for the annihilation, is reduced noticeably by the increase of the distance between pins, or the increase in the pin size. A simulation of the magnetic vortex pinning in the sample of size 32(Xi) x 32(Xi) suggests we are likely to achieve pinning of the vortex-antivortex pair with the sample size around this and vortex-antivortex separation of 22(Xi). Using this sample as a template, the maximum density of pinned vortices achievable is calculates to be about 7.6 x 10^14 vortices/m2 for (Xi) =~ 1.6A�.
Kim, Sangbum
Institute of Development Studies Feed | Open Energy Information
Institute of Development Studies Feed Institute of Development Studies Feed Jump to: navigation, search Home | About | Inventory | Partnerships | Capacity Building | Webinars | Reports | Events | News | List Serve CLEAN Member Feeds Center for Environment and National Security at Scripps Centro de Energías Renovables (CER) The Children's Investment Fund Foundation (CIFF) Climate and Development Knowledge Network (CDKN) Climate Technology Initiative (CTI) ClimateWorks Foundation Coalition for Rainforest Nations (CfRN) Ecofys Energy Research Centre of the Netherlands (ECN) Energy Sector Management Assistance Program of the World Bank (ESMAP) Environment and Development Action in the Third World (ENDA-TM) German Aerospace Center (DLR) German Agency for International Cooperation (GIZ) Global Village Energy Partnership (GVEP)
Institute of Development Studies (IDS) | Open Energy Information
Institute of Development Studies (IDS) Institute of Development Studies (IDS) Jump to: navigation, search Logo: Institute of Development Studies Name Institute of Development Studies Address Library Road, Brighton, East Sussex Place Brighton, UK Zip BN1 9RE Number of employees 201-500 Year founded 1966 Phone number +44 (0)1273 606261 Coordinates 50.8659583°, -0.0901136° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":50.8659583,"lon":-0.0901136,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}
Study in Indonesia and gain credit towards your degree! DevelopmentStudiesImmersionProgram ACICIS
Study in Indonesia and gain credit towards your degree! DevelopmentStudiesImmersionProgram ACICIS an internship in Indonesia! © Photograph by James Walsh #12;w w w . a c i c i s . m u r d o c h . e d u . a u development issues in Indonesia while also gaining im- portant practical skills related to advocacy
Development of a Simulation Model for Fluidized Bed Mild Gasifier.
?? A mild gasification method has been developed to provide an innovative clean coal technology. The objective of this study is to developed a numerical� (more)
Mazumder, AKM Monayem Hossain
An experimental and numerical study of the modifications of mixed-layer structure by inhomogeneous surface fluxes and secondary circulations
The problem of scale interactions in the planetary boundary layer (PBL), i.e., how forcing mechanisms of differing spatial and temporal scales affect the properties of the PBL, has been a subject of considerable interest for some time. One aspect of this problem that has received increasing attention in recent years is the representation, in mesoscale and general circulation models. of the effects of subgrid-scale inhomogeneities in surface properties. Differences in sensible and latent heat fluxes between adjacent areas can result in secondary circulations. modifications to the boundary layer structure, and the transport of heat and moisture from one area to another. Despite their potential included on local PBL properties, such effects can not be resolved by numerical models whose scale is too coarse; thus, suitable parameterizations that account for these phenomena are needed. In this paper the authors present some results of wind and temperature measurements over an area with significant variations in surface fluxes on scales of O(10 km). They then use fine resolution numerical simulations to show how synoptic, topographical, and thermal forcing combine to affect the properties of the PBL in the region. Specifically, they consider the relative importance of topography and land-use differences on the generation of secondary circulations and on the depth of the mixed layer, and they show how these effects are modified by synoptic wind fields. Implications for coarser resolution models are also discussed.
Case studies of current trends in development geology
Traditionally, development geologists have been responsible for studying leases, logs, and cores in detail in support of engineering functions. These responsibilities have grown from defining gross reservoir geometries to understanding subtle differences in reservoirs attributed to stratigraphic and structural complexities, depositional environments, and hydrodynamic processes. To handle these increased responsibilities, expertise has become essential in the areas of computer applications, log analysis, modeling, and management of produced water. Examples of the use and application of each area to projects from fields on the west side of the San Joaquin Valley demonstrate current techniques employed by development geologists and the evolution of a development department within Texaco. A study of a property in the South Belridge field on which 330 wells were drilled over a two-year period illustrates how computer resources have become vital in handling the vast amount of data needed to perform detailed geologic studies. Intricate geologic characterization has become essential to optimizing and defining reservoir performance in several fields: (1) Southeast Lost Hills, a complex diagenetic trap; (2) Buena Vista Hills, where log analysis is needed to make reserve estimates and step-out potential meaningful; (3) Midway-Sunset field, for which detailed geology leads to new field-wide models and future prospects. Increasing environmental concern over waste disposal has required an important involvement of development geologists in the geologic and hydrologic aspects of subsurface injection of produced water and other brines in the Santiago Creek field. Instead of providing a training ground for future explorationists, development geology should be viewed as an alternative career with potential for a much greater demand in the future.
Livingston, N.D.
Case studies of geothermal leasing and development on federal lands
In response to a widely expressed need to examine the impact of the federal regulatory system on the rate of geothermal power development, the Department of Energy-Division of Geothermal Energy (DGE) has established a Streamlining Task Force in cooperation with appropriate federal agencies. The intent is to find a way of speeding development by modification of existing laws or regulations or by better understanding and mechanization of the existing ones. The initial focus was on the leasing and development of federal lands. How do the existing processes work? Would changes produce positive results in a variety of cases? These are questions which must be considered in a national streamlining process. This report presents case studies of federal leasing actions on seven diverse locations in the western region. Characteristics of existing high geothermal potential areas are quite diverse; geography, environment, industry interest and the attitudes and activities of the responsible federal land management agencies and the interested public vary widely. Included are descriptions of post and current activities in leasing exploration and development and discussions of the probable future direction of activities based on current plans. Implications of these plans are presented. The case studies were based on field interviews with the appropriate State and District BLM officer and with the regional forester's office and the particular forest office. Documentation was utilized to the extent possible and has been included in whole or in part in appendices as appropriate.
Trummel, Marc
Explosives program development study: Phase 3, Final report
Under the sponsorship of Lawrence Livermore National Laboratory (LLNL) and the Defense Advanced Research Agency (DARPA), The BDM Corporation has been conducting a survey and assessment of the status of research and development in high energy materials, particulary explosives. The objectives of the DARPA Explosives Program Development Study is to provide LLNL and DARPA with: (1) An assessment of the current research and development in high energy materials and an identification of needs for further work; (2) A set of recommendations to address those needs with DARPA (3) A program plan to implement these recommendations. The study consisted of review of papers from the principal high energy materials research and development conferences of 1985 - 1987; personal and telephone interviews with experts in the field in military services and DOE laboratories; review of papers of the ONR detonation symposia; principal technical journals; government reports; and a questionnaire survey of the explosives community for their ranking of research topics in materials. Four principal categories of operational issues and requirements were surveyed: energetic materials; performance; sensitivity/vulnerability; and manufacture and cost factors. These four categories are fully covered. 24 refs.
Hill, M.E.
Geothermal development of the Madison group aquifer: a case study
A geothermal well has been drilled at the St. Mary's Hospital in Pierre, South Dakota. The well is 2176 feet deep and artesian flows 375 gpm at 106/sup 0/F. The well is producing fluids from the Mississippian Madison Group, a sequence of carbonate rocks deposited over several western states. The project was funded to demonstrate the goethermal potential of this widespread aquifer. This case study describes the development of the project through geology, drilling, stimulation, and testing.
Martinez, J.A.
Numerical studies of fluid-rock interactions in Enhanced Geothermal Systems (EGS) with CO2 as working fluid
Development of Enhanced Geothermal Systems,� paper presentedin the Deep Reservoir of the Mt. Amiata Geothermal Field,Italy,� Transactions, Geothermal Resources Council, 31, 153-
Factor Separation in Numerical Simulations
A simple method is developed for computing the interactions among various factors influencing the atmospheric circulations. It is shown how numerical simulations can be utilized to obtain the pure contribution of any factor to any predicted field,...
U. Stein; P. Alpert
Hawaii Solar Integration Study: Solar Modeling Developments and Study Results; Preprint
The Hawaii Solar Integration Study (HSIS) is a follow-up to the Oahu Wind Integration and Transmission Study completed in 2010. HSIS focuses on the impacts of higher penetrations of solar energy on the electrical grid and on other generation. HSIS goes beyond the island of Oahu and investigates Maui as well. The study examines reserve strategies, impacts on thermal unit commitment and dispatch, utilization of energy storage, renewable energy curtailment, and other aspects of grid reliability and operation. For the study, high-frequency (2-second) solar power profiles were generated using a new combined Numerical Weather Prediction model/ stochastic-kinematic cloud model approach, which represents the 'sharp-edge' effects of clouds passing over solar facilities. As part of the validation process, the solar data was evaluated using a variety of analysis techniques including wavelets, power spectral densities, ramp distributions, extreme values, and cross correlations. This paper provides an overview of the study objectives, results of the solar profile validation, and study results.
Orwig, K.; Corbus, D.; Piwko, R.; Schuerger, M.; Matsuura, M.; Roose, L.
Coherent femtosecond low-energy single-electron pulses for time-resolved diffraction and imaging: A numerical study
We numerically investigate the properties of coherent femtosecond single electron wave packets photoemitted from nanotips in view of their application in ultrafast electron diffraction and non-destructive imaging with low-energy electrons. For two different geometries, we analyze the temporal and spatial broadening during propagation from the needle emitter to an anode, identifying the experimental parameters and challenges for realizing femtosecond time resolution. The simple tip-anode geometry is most versatile and allows for electron pulses of several ten of femtosecond duration using a very compact experimental design, however, providing very limited control over the electron beam collimation. A more sophisticated geometry comprising a suppressor-extractor electrostatic unit and a lens, similar to typical field emission electron microscope optics, is also investigated, allowing full control over the beam parameters. Using such a design, we find {approx}230 fs pulses feasible in a focused electron beam. The main limitation to achieve sub-hundred femtosecond time resolution is the typical size of such a device, and we suggest the implementation of more compact electron optics for optimal performance.
Paarmann, A.; Mueller, M.; Ernstorfer, R. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Gulde, M.; Schaefer, S.; Schweda, S.; Maiti, M.; Ropers, C. [Courant Research Center Physics and Material Physics Institute, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Xu, C. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, 390, Qinghe Road, Jiading, Shanghai 201800 (China); Hohage, T. [Institute of Numerical and Applied Mathematics, University of Goettingen, Lotzestr. 16-18, 37083 Goettingen (Germany); Schenk, F. [Courant Research Center Physics and Material Physics Institute, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Institute of Numerical and Applied Mathematics, University of Goettingen, Lotzestr. 16-18, 37083 Goettingen (Germany)
HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses
In our study, a series of lab-scale crucible tests were performed on designed glasses of different compositions to further investigate and simulate the effect of Cr, Ni, Fe, Al, Li, and RuO2 on the accumulation rate of spinel crystals in the glass discharge riser of the HLW melter. The experimental data were used to expand the compositional region covered by an empirical model developed previously (Maty� et al. 2010b), improving its predictive performance. We also investigated the mechanism for agglomeration of particles and impact of agglomerates on accumulation rate. In addition, the TL was measured as a function of temperature and composition.
Matyas, Josef; Huckleberry, Adam R.; Rodriguez, Carmen P.; Lang, Jesse B.; Owen, Antionette T.; Kruger, Albert A.
Regional Study to Guide Policy Interventions for Enhancing the Development
Guide Policy Interventions for Enhancing the Development Guide Policy Interventions for Enhancing the Development and Transfer of Publicly-Funded Environmentally Sound Technologies in Asia and the Pacific Region Jump to: navigation, search Name Regional Study to Guide Policy Interventions for Enhancing the Development and Transfer of Publicly-Funded Environmentally Sound Technologies in Asia and the Pacific Region Agency/Company /Organization United Nations Economic and Social Commission for Asia and the Pacific Sector Energy Focus Area Energy Efficiency, Renewable Energy Topics Implementation, Policies/deployment programs Resource Type Publications Website http://www.greengrowth.org/dow UN Region Central Asia, Eastern Asia, South-Eastern Asia, "Pacific" is not in the list of possible values (Eastern Africa, Middle Africa, Northern Africa, Southern Africa, Western Africa, Caribbean, Central America, South America, Northern America, Central Asia, Eastern Asia, Southern Asia, South-Eastern Asia, Western Asia, Eastern Europe, Northern Europe, Southern Europe, Western Europe, Australia and New Zealand, Melanesia, Micronesia, Polynesia, Latin America and the Caribbean) for this property.
A Case Study of the 9 August 1988 South Atlantic Storm: Numerical Simulations of the Wave Activity
During 9�11 August 1988, a cyclone developed over Uruguay in the Ice of the Andes Mountains and moved over the South Atlantic Ocean, where it redeveloped into an intense storm. This storm was responsible for unusual wave activity along the ...
Feasibility Study for Renewable Energy Development on Tribal Lands
Project Objective: The Mississippi Band of Choctaw Indians (MBCI) conducted a study of the feasibility of siting a renewable energy biomass-based installation on tribal lands. The purpose of the study was to determine whether such an installation can be economically sustainable, as well as consistent with the cultural, social, and economic goals of the Tribe. Scope: To achieve the goal of the feasibility study, the following tasks were carried out: (1) Resource availability assessment--The objective of this assessment was to determine the availability of both poultry litter and wood residues for use in the proposed facility. (2) Power utilization assessment--The objective of this assessment was to determine the potential market size for power produced, the existing infrastructure for delivering power to that market, and the costs and economic returns for doing so. (3) Technology review--The objective of this review was to identify one, or more, technical options for detailed economic and technical assessment. The study considered a range of feedstock and product mixtures of poultry litter; wood residues as feedstock; and electrical power and other ancillary products as outputs. Distributed power sources was also examined. Technologies ranging from gasification to systems that produce both power and value-added chemicals were considered. Technologies selected for detailed review were those that can be sized to process the amount of available feed (poultry litter, or poultry litter and wood residues), and that also appear to make economic sense in terms of the value of their inputs. The technology review leaned heavily on the experience from similar prior DOE projects, particularly those conducted by the National Renewable Energy Laboratory (NREL). NREL was involved in a consultative role, so that the project team could leverage their experience. (4) Systems Design(s)--Based on the technology review, a pre-conceptual design for an installation was developed. This included identification of unit operations and equipment, maintenance, manpower, feedstock requirements, and output (power and any other ancillary products). Energy and mass flows were identified. (5) Manpower development assessment--The objectives of this assessment was to identify training needs for the selected option(s), and determine how they can best be met. Using the manpower estimates from the pre-conceptual system design, skills and training needs were to be identified. A plan for providing the needed manpower was to be developed, and any associated costs determined. (6) Economic assessment--The objective of this assessment was to determine the economic viability and sustainability of the technology option(s) identified through the technical review option. The costs of bringing the feedstock to the proposed facility were combined with nominal operation costs and potential production distribution costs to identify total costs. Revenue from power distribution (and, possibly, from sale of ancillary products) were combined with any possible government credits or payments to identify gross revenue. Economic viability was determined by net revenue and return on investment. A business plan for the selected option was to be produced that would consider long-term sustainability of the project. (7) MBCI compatibility assessment--The objective of this assessment was to determine whether the renewable energy technology was compatible with the MBCI's cultural, social and economic values. As part of this assessment, the environmental impacts and benefits were to be determined (Environmental stewardship is an important part of the Choctaw culture.). The effects of a project on employment were projected. The compatibility of the renewable energy project with MBCI cultural and social values were determined. Most importantly, the compatibility of the renewable energy installation with the MBCIs economic development goals and directions were determined. A project team led by the Mississippi Band of Choctaw Indians (MBCI) conducted the feasibility study. The team included th
John Hendrix, Project Director; Charles Weir, Project Manager; Dr. John Plodinec, Technology Advisor; Dr. Steve Murray, Economic Advisor
A Numerical Study on the Atmospheric Circulation over the Midlatitude North Pacific during the Last Glacial Maximum
The dynamics of the atmospheric circulation change over the midlatitude North Pacific under the boundary conditions during the last glacial maximum (LGM) have been studied by atmospheric general circulation models (GCMs) with different ocean ...
Wataru Yanase; Ayako Abe-Ouchi
A Numerical Study of Stratospheric Gravity Waves Triggered by Squall Lines Observed during the TOGA COARE and COPT-81 Experiments
A 3D mesoscale model is used to study the structure and intensity of stratospheric gravity waves generated by tropical convection. Two prototypical cases are examined: a squall line observed during the Tropical Ocean Global Atmosphere Coupled ...
C. Piani; D. R. Durran
Numerical Model Simulation of Human Biometeorological Heat Load Conditions�Summer Day Case Study for the Chesapeake Bay Area
During the warm season the spatial and temporal behavior of the biometeorological heat load in coastal regions is highly complex. Observational studies attempting to describe it usually are incomplete due to the scarcity of available ...
Mordecay Segal; Roger A. Pielke
Numerical Study of Urban Impact on Boundary Layer Structure: Sensitivity to Wind Speed, Urban Morphology, and Rural Soil Moisture
A mesoscale model with a detailed urban surface exchange parameterization is used to study urban influences on boundary layer structure. The parameterization takes into account thermal and mechanical factors, and it is able to reproduce the most ...
Alberto Martilli
A Potential Vorticity-Based Study of the Role of Diabatic Heating and Friction in a Numerically Simulated Baroclinic Cyclone
A particularly intense case of western Atlantic baroclinic cyclogenesis was investigated in this study. Specifically, the roles of latent heat of condensation and surface friction were examined from the potential vorticity or �PV thinking� ...
Mark T. Stoelinga
Effects of Spatial Variations of Soil Moisture and Vegetation on the Evolution of a Prestorm Environment: A Numerical Case Study
To study the effects of spatial variations of soil moisture and coverage coverage on the evolution of a prestorm environment, the Goddard mesoscale model (GMASS) was modified to incorporate a simple evapo-transpiration model that requires them ...
Jy-Tai Chang; Peter J. Wetzel
An Air�Sea Interaction Theory for Tropical Cyclones. Part II: Evolutionary Study Using a Nonhydrostatic Axisymmetric Numerical Model
In Part I of this study an analytical model for a steady-state tropical cyclone is constructed on the assumption that boundary-layer air parcels are conditionally neutral to displacements along the angular momentum surfaces of the hurricane ...
Richard Rotunno; Kerry A. Emanuel
Experimental and numerical study of the behavior of three-way catalytic converters under different engine operation conditions
The thesis reports the studies on how the three-way catalytic converters behave under different operation conditions. The main focus of the work is in the oxygen storage capacity of the three-way catalyst. Rich-to-lean ...
Zhang, Yuetao
Compact Gamma-ray Source Technology Development Study
This study focuses on the applicability of current accelerator and laser technologies to the construction of compact, narrow bandwidth, gamma-ray sources for DHS missions in illicit materials detection. It also identifies research and development areas in which advancement will directly benefit these light sources. In particular, we review the physics of Compton scattering based light sources and emphasize the source properties most important to Nuclear Resonance Fluorescence (NRF) applications of interest. The influences of laser and electron beam properties on the light source are examined in order to evaluate the utility of different technologies for this application. Applicable bulk and fiber-based laser systems and laser recirculation technologies are discussed and Radio Frequency (RF) Linear Accelerator (linac) technologies are examined to determine the optimal frequency and pulse formats achievable.
Anderson, S G; Gibson, D J; Rusnak, B
A case study: demands on component-based development
Building software systems with reusable components brings many advantages. The development becomes more efficient, the realibility of the products is enhanced, and the maintenance requirement is significantly reduced. Designing, developing and maintaining ... Keywords: architecture, component-based development, development environment, reuse, standard components
Ivica Crnkovic; Magnus Larsson
Seasonality of the Kuroshio Path Destabilization Phenomenon in the Okinawa Trough: A Numerical Study of Its Mechanism
Previous observations have indicated that the Kuroshio�s path in the northern Okinawa Trough of the East China Sea is destabilized and accompanied by meanders with periods of 1�3 months during the winter�spring period. The present study ...
Hirohiko Nakamura; Masami Nonaka; Hideharu Sasaki
Effects of Cloud Seeding, Latent Heat of Fusion, and Condensate Loading on Cloud Dynamics and Precipitation Evolution: A Numerical Study
This study attempts to isolate the dynamic and microphysical effects of seeding. A two-dimensional, time-dependent cloud model has been used to simulate silver iodide (AgI) seeding of convective clouds. Two major dynamic effects (latent heat of ...
Harold D. Orville; Jeng-Ming Chen
A Numerical Study of the Interaction between a Deep Cold Jet and the Bottom Boundary Layer of the Ocean
A two-dimensional (x-z) primitive equation model is used to study the interaction between a deep cold jet on a sloping bottom and the bottom boundary layer (BBL) of the deep ocean. Two closure schemes are used: a standard second order turbulence ...
Tal Ezer; Georges L. Weatherly
Numerical Simulation and Test Study on Non-uniform Area Of Round-ended CFST Tubular Tower
The impacts of Poisson ratio of core concrete on the bearing capacity of round-ended CFST tubular tower and non-uniform area were analyzed with test study and the sub-model technology, the most disadvantaged stress state of the structure under the triaxial ... Keywords: round-ended concrete-filled steel(CFST), triaxial compression, Poisson's ratio(�), sub-model method, Micro-expansive
Jian-xiong Xie; Zhe-an Lu
Feasibility of steam injection process in a thin, low-permeability heavy oil reservoir of Arkansas -- a numerical simulation study
This report details the findings of an in-depth study undertaken to assess the viability of the steam injection process in the heavy oil bearing Nacatoch sands of Arkansas. Published screening criteria and DOE`s steamflood predictive models were utilized to screen and select reservoirs for further scrutiny. Although, several prospects satisfied the steam injection screening criteria, only a single candidate was selected for detailed simulation studies. The selection was based on the availability of needed data for simulation and the uniqueness of the reservoir. The reservoir investigated is a shallow, thin, low-permeability reservoir with low initial oil saturation and has an underlying water sand. The study showed that the reservoir will respond favorably to steamdrive, but not to cyclic steaming. Steam stimulation, however, is necessary to improve steam injectivity during subsequent steamdrive. Further, in such marginal heavy oil reservoirs (i.e., reservoir characterized by thin pay zone and low initial oil saturation) conventional steamdrive (i.e., steam injection using vertical wells) is unlikely to be economical, and nonconventional methods must be utilized. It was found that the use of horizontal injectors and horizontal producers significantly improved the recovery and oil-steam ratio and improved the economics. It is recommended that the applicability of horizontal steam injection technology in this reservoir be further investigated.
Sarkar, A.K.; Sarathi, P.S.
In response to Technical Task Request (TTR) HLW-SSF-TTR-2012-0017 (1), SRNL performed modeling studies to evaluate alternative design features for the 32 million gallon Saltstone Disposal Unit (SDU) referred to as SDU 6. This initial modeling study was intended to assess the performance of major components of the structure that are most significant to the PA. Information provided by the modeling will support the development of a SDU 6 Preliminary Design Model and Recommendation Report to be written by SRR Closure and Waste Disposal Authority. Key inputs and assumptions for the modeling were provided to SRNL in SRR-SPT-2011-00113 (2). A table reiterates the base case and four sensitivity case studies requested in this reference. In general, as shown in Table 4, when compared to Vault 2 Case A, the Base Case SDU 6 design produced higher peak fluxes to the water table during the 10,000 year period of analysis but lower peak fluxes within a 15,000 to 20,000 time frame. SDU 6 will contain approximately ten times the inventory of a single Vault 2 and the SDU 6 footprint is comparable to that of a group of four Vault 2 disposal units. Therefore, the radionuclide flux from SDU 6 and that from a single Vault 2 are not directly comparable. A more direct comparison would be to compare the maximum dose obtained at the 100 m boundary from the seven SDU's that will replace the 64 FDC's analyzed in the 2009 PA. This analysis will be performed in the next set of calculations planned for SDU design evaluation. Aquifer transport and dose calculations were not intended to be part of this initial scoping study. However, results from this study do indicate that replacement of the FDC design with SDU would not yield significantly higher peak doses. If the thickness of the SDU 6 floor is increased, peak doses would not occur during the 10,000 year period of analysis.
Smith, F.
A numerical sensitivity analysis of streamline simulation
Nowadays, field development strategy has become increasingly dependent on the results of reservoir simulation models. Reservoir studies demand fast and efficient results to make investment decisions that require a reasonable trade off between accuracy and simulation time. One of the suitable options to fulfill this requirement is streamline reservoir simulation technology, which has become very popular in the last few years. Streamline (SL) simulation provides an attractive alternative to conventional reservoir simulation because SL offers high computational efficiency and minimizes numerical diffusion and grid orientation effects. However, streamline methods have weaknesses incorporating complex physical processes and can also suffer numerical accuracy problems. The main objective of this research is to evaluate the numerical accuracy of the latest SL technology, and examine the influence of different factors that may impact the solution of SL simulation models. An extensive number of numerical experiments based on sensitivity analysis were performed to determine the effects of various influential elements on the stability and results of the solution. Those experiments were applied to various models to identify the impact of factors such as mobility ratios, mapping of saturation methods, number of streamlines, time step sizes, and gravity effects. This study provides a detailed investigation of some fundamental issues that are currently unresolved in streamline simulation.
Chaban Habib, Fady Ruben
OPTICAL INSTRUMENTATION FOR REACTOR SAFETY STUDIES B.T.OPTICAL INSTRUMENTATION FOR REACTOR SAFETY STUDIES B.T.instru� mentation for reactor safety studies is described.
Turko, B.T.
Numerical methods for electromagnetic wave propagation and scattering in complex media
Numerical methods are developed to study various applications in electromagnetic wave propagation and scattering. Analytical methods are used where possible to enhance the efficiency, accuracy, and applicability of the ...
Moss, Christopher D. Q. (Christopher Doniert Q.), 1973-
The Effects of Subgrid Model Mixing and Numerical Filtering in Simulations of Mesoscale Cloud Systems
Using the newly developed Weather Research and Forecasting (WRF) model, this study investigates the effects of subgrid mixing and numerical filtering in mesoscale cloud simulations by examining the sensitivities to the parameters in turbulence-...
Tetsuya Takemi; Richard Rotunno
Numerical Simulations of a Buoyancy-Driven Coastal Countercurrent off Vancouver Island
A three-dimensional prognostic numerical model has been developed to study the ocean circulation around Vancouver Island, British Columbia. In a series of simulations, the model is applied to examine the role of buoyancy forcing in the dynamics ...
Diane Masson; Patrick F. Cummins
Numerical Simulation of a Subtropical Squall Line over the Taiwan Strait
A two-dimensional, time-dependent, and nonhydrostatic numerical cloud model is used to study the development and structure of a subtropical squall line that occurred during TAMEX (Taiwan Area Mesoscale Experiment). The model includes a ...
Wei-Kuo Tao; Joanne Simpson; Su-Tzai Soong
A Numerical Investigation of the Structure of vorticity Fields Associated with a Deep Convective Cloud
The structure of vorticity fields of cumulus clouds is studied using a three-dimensional numerical convection model developed by Clark (1977, 1979. 1981). The analysis of the model results suggests that 1) it is justified to neglect the ...
Han-Ru Cho; Terry L. Clark
A Numerical Feasibility Study of Three-Component Induction Logging for Three Dimensional Imaging About a Single Borehole
A theoretical analysis has been completed for a proposed induction logging tool designed to yield data which are used to generate three dimensional images of the region surrounding a well bore. The proposed tool consists of three mutually orthogonal magnetic dipole sources and multiple 3 component magnetic field receivers offset at different distances from the source. The initial study employs sensitivity functions which are derived by applying the Born Approximation to the integral equation that governs the magnetic fields generated by a magnetic dipole source located within an inhomogeneous medium. The analysis has shown that the standard coaxial configuration, where the magnetic moments of both the source and the receiver are aligned with the axis of the well bore, offers the greatest depth of sensitivity away from the borehole compared to any other source-receiver combination. In addition this configuration offers the best signal-to-noise characteristics. Due to the cylindrically symmetric nature of the tool sensitivity about the borehole, the data generated by this configuration can only be interpreted in terms of a two-dimensional cylindrical model. For a fill 3D interpretation the two radial components of the magnetic field that are orthogonal to each other must be measured. Coil configurations where both the source and receiver are perpendicular to the tool axis can also be employed to increase resolution and provide some directional information, but they offer no true 3D information.
Millennial Development: A Case Study of Namibia's Vision 2030.
?? This thesis analyzes the neoliberal governmentalities of the Millennium Development Goals (MDGs) and how they shape the policies, practices, and perceptions of poverty within� (more)
Connoy, Laura
A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing boundary conditions in heat and mass transport modules. However, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes.
Piro, Markus [Royal Military College of Canada; Lewis, Brent [Royal Military College of Canada; Thompson, Dr. William T. [Royal Military College of Canada; Simunovic, Srdjan [ORNL; Besmann, Theodore M [ORNL
NOAA/NMFS Developments NOAA Funds Major Alaskan Marine Studies
from outer continental shelf oil and gas exploration and development. RESEARCH CONTINUED ON OIL impacts of oil exploration and development activities on Alaska's outer continental shelf. BASELINE University (OSU) at Corvallis to contin ue research on the effects of oil spills on fish, shellfish, marine
Study on the development of the public Study on the development of the public transmission network around Go�land until 2030.
?? The project was performed in RTE (�R�seau de Transport d�Electricit�), the French Transmission System Operator (TSO) within the Network Optimisation and Development Service (SDOP)� (more)
Guyot, Emilie Solange Lucienne
New product development methods : a study of open design
This thesis explores the application of open design to the process of developing physical products. Open design is a type of decentralized innovation that is derived from applying principles of open source software and ...
Smith, Ariadne G. (Ariadne Genevi�ve)
Galileo Lofts : a real estate development feasibility study
In August 2004, a development proposal titled "Galileo Lofts at MIT: Housing and Urban Park" was submitted to the Cambridge Redevelopment Authority for the provision of new housing and a public park on Parcel 7, in Kendall ...
Ledohowski, Lea J. (Lea Joel)
Numerical Simulation of Drainage Flow in Brush Creek, Colorado
One of the objectives of the Atmospheric Studies in Complex Terrain (ASCOT) program is to develop numerical models that can be used to aid in the understanding and prediction of flow patterns observed over complex terrain. As part of this program,...
John M. Leone Jr.; Robert L. Lee
Renewable Energy Laboratory Development for Biofuels Advanced Combustion Studies
The research advanced fundamental science and applied engineering for increasing the efficiency of internal combustion engines and meeting emissions regulations with biofuels. The project developed a laboratory with new experiments and allowed investigation of new fuels and their combustion and emissions. This project supports a sustainable domestic biofuels and automotive industry creating economic opportunities across the nation, reducing the dependence on foreign oil, and enhancing U.S. energy security. The one year period of research developed fundamental knowledge and applied technology in advanced combustion, emissions and biofuels formulation to increase vehicle's efficiency. Biofuels�?? combustion was investigated in a Compression Ignition Direct Injection (DI) to develop idling strategies with biofuels and an Indirect Diesel Injection (IDI) intended for auxiliary power unit.
Soloiu, Valentin
Java and Numerical Computing
Java represents both a challenge and an opportunity to practitioners of numerical computing. This article analyzes the current state of Java in numerical computing and identifies some directions for the realization of its full potential.
Ronald F. Boisvert; Jos� Moreira; Michael Philippsen; Roldan Pozo
Development of Industrial Benchmark FEA Model to Study Energy ...
A study has been undertaken using thermo-electrical-mechanical finite element analysis of the cast iron to carbon contact for an anode assembly. The contact�...
Study on the Feasibility of Bioenergy Development in China
To develop bioenergy characterized with environment friendliness and renew ability is inevitable to undergo, in order to solve the problem of fossil energy shortage, to respond to such disastrous consequence as greenhouse effect and acrid rain on the ... Keywords: fossil energy, energy crisis, renewable energy, bioenergy
Shen Xilin
A Study of the Early Winter Effects of the Great Lakes.I: Comparison of Very Fine Scale Numerical Simulations with Observed Data
Development of a framework for study of the Great Lakes' effects on late fall-early winter cyclones andArctic air masses has been initiated. The central theoretical component is a three-dimensional numericalprimitive equations model. The 40-45 km ...
Douglas B. Boudra
Formulation, analysis and numerical study of an optimization-based conservative interpolation (remap) of scalar fields for arbitrary Lagrangian-Eulerian methods
We develop and study the high-order conservative and monotone optimization-based remap (OBR) of a scalar conserved quantity (mass) between two close meshes with the same connectivity. The key idea is to phrase remap as a global inequality-constrained ... Keywords: Constrained interpolation, FCT, Flux-corrected remap, Optimization-based remap, Quadratic programming, Remap
Pavel Bochev; Denis Ridzal; Guglielmo Scovazzi; Mikhail Shashkov
Economic Development Benefits of the Mars Hill Wind Farm, Wind Powering America Rural Economic Development, Case Study (Fact Sheet)
This case study summarizes the economic development benefits of the Mars Hill Wind Farm to the community of Mars Hill, Maine. The Mars Hill Wind Farm is New England's first utility-scale wind farm.
Technical Update -- Planning Study Model Development and Management
Presently, there has been an increase in the deployment of modern transmission technologies such as static var compensation devices and high-voltage direct-current (HVDC) transmission systems.�The deployment of HVDC is likely to increase given the many proposals presently for bringing large and remote pockets of wind generation resources to load centers and proposals in Europe for the development of off-shore grids for wind generation. Furthermore, the deployment of static var compensation ...
Continuation of Studies on Development of ODS Heat Exchanger Tubing
The Department of Energy (DOE), National Energy Technology Center (NETL), has initiated a strategic plan for the development of advanced technologies needed to design and build fossil fuel plants with very high efficiency and environmental performance. These plants, referred to as 'Vision 21' and FutureGen programs by DOE, will produce electricity, chemicals, fuels, or a combination of these products, and possibly secondary products such as steam/heat for industrial use. MA956 is a prime candidate material being considered for a high temperature heat exchanger in the 'Vision 21' and FutureGen programs. This material is an oxide dispersion strengthened (ODS) alloy; however, there are some gaps in the data required to commit to the use of these alloys in a full-size plant. To fill the technology gaps for commercial production and use of the material for 'Advanced Power Generation Systems' this project has performed development activity to significant increase in circumferential strength of MA956 as compared to currently available material, investigated bonding technologies for bonding tube-to-tube joints through joining development, and performed tensile, creep and fire-side corrosion tests to validate the use and fabrication processes of MA956 to heat exchanger tubing applications. Development activities within this projected has demonstrated increased circumferential strength of MA956 tubes through flow form processing. Of the six fabrication technologies for bonding tube-to-tube joints, inertia friction welding (IFW) and flash butt welding (FBW) were identified as processes for joining MA956 tubes. Tensile, creep, and fire-side corrosion test data were generated for both base metal and weld joints. The data can be used for design of future systems employing MA956. Based upon the positive development activities, two test probes were designed and fabricated for field exposure testing at 1204 C ({approx}2200 F) flue gas. The probes contained tube portions with FBW and IFW welded MA956. Field testing of the probes and remaining heat exchanger design activity will be performed by Oak Ridge National Laboratory under DOE Contract DE-AC05-00OR22725.
Lawrence Brown; David Workman; Bimal Kad; Gaylord Smith; Archie Robertson; Ian Wright
Numerical study on convection diffusion for gasification agent in underground coal gasification. Part I: establishment of mathematical models and solving method
The aim of this article is to discuss the distribution law of the gasification agent concentration in a deep-going way during underground coal gasification and the new method of solving the problem for the convection diffusion of the gas. In this paper, the basic features of convection diffusion for the gas produced in underground coal gasification are studied. On the basis of the model experiment, through the analysis of the distribution and patterns of variation for the fluid concentration field in the process of the combustion and gasification of the coal seams within the gasifier, the 3-D non-linear unstable mathematical models on the convection diffusion for oxygen are established. In order to curb such pseudo-physical effects as numerical oscillation and surfeit which frequently occurred in the solution of the complex mathematical models, the novel finite unit algorithm, the upstream weighted multi-cell balance method is advanced in this article, and its main derivation process is introduced.
Yang, L.H.; Ding, Y.M. [China University of Mining & Technology, Xuzhou (China). College of Resources and Geoscience
A Numerical Model for Chemical and Meteorological Processes in the Atmospheric Boundary Layer. Part I: A Model Description and a One-Dimensional Parameter Study
A numerical flow model is presented for the atmospheric boundary layer, including dispersion and chemical transformations of air pollutants. The model is a three-dimensional time-dependent one for the mesoscale based on the conservation equations ...
Gunilla Svensson
A Numerical Study of the Evolving Convective Boundary Layer and Orographic Circulation around the Santa Catalina Mountains in Arizona. Part I: Circulation without Deep Convection
The daytime evolution of the thermally forced boundary layer (BL) circulation over an isolated mountain, about 30 km in diameter and 2 km high, is examined by means of numerical simulations validated with data collected in the Cumulus ...
J. Cory Demko; Bart Geerts
Response of the Wintertime Northern Hemisphere Atmospheric Circulation to Current and Projected Arctic Sea Ice Decline: A Numerical Study with CAM5
The wintertime Northern Hemisphere (NH) atmospheric circulation response to current (2007�12) and projected (2080�99) Arctic sea ice decline is examined with the latest version of the Community Atmospheric Model (CAM5). The numerical experiments ...
Yannick Peings; Gudrun Magnusdottir
Renewable Energy Development on Fort Mojave Reservation Feasiblity Study
The Ft. Mojave tribe, whose reservation is located along the Colorado River in the states of Arizona, California, and Nevada near the point where all three states meet, has a need for increased energy supplies. This need is a direct result of the aggressive and successful economic development projects undertaken by the tribe in the last decade. While it is possible to contract for additional energy supplies from fossil fuel sources it was the desire of the tribal power company, AHA MACAV Power Service (AMPS) to investigate the feasibility and desirability of producing power from renewable sources as an alternative to increased purchase of fossil fuel generated power and as a possible enterprise to export green power. Renewable energy generated on the reservation would serve to reduce the energy dependence of the tribal enterprises on off reservation sources of energy and if produced in excess of reservation needs, add a new enterprise to the current mix of economic activities on the reservation. Renewable energy development would also demonstrate the tribe�s support for improving environmental quality, sustainability, and energy independence both on the reservation and for the larger community.
Russell Gum, ERCC analytics LLC
2002 Fusion Summer Study Subgroup E4 -Development Pathway Subgroup
from various sources of energy in 2020 (date from Fusion Summer Study 1998). Geothermal energy 0.1 0 of superior access for test-modules and a 400-sec flattop in inductive operation, which is long enough - advanced divertor - pulse length sufficient for first wall and blanket thermal equilibrium - superior
Najmabadi, Farrokh
Latent Heating and Cooling Rates in Developing and Nondeveloping Tropical Disturbances during TCS-08: Radar-Equivalent Retrievals from Mesoscale Numerical Models and ELDORA
Latent heating and cooling rates have a critical role in predicting tropical cyclone formation and intensification. In a prior study, Park and Elsberry estimated the latent heating and cooling rates from aircraft Doppler radar [Electra Doppler ...
Myung-Sook Park; Andrew B. Penny; Russell L. Elsberry; Brian J. Billings; James D. Doyle
Study of Hanford capability for solar energy research and development
The Hanford site provides unique capability for solar energy research and development. The basic attributes include large available land areas; consistent sunshine during much of the year (although not comparable to Arizona and the southwest U. S.); ex- treme temperatures for test purposes (--27 to 115 F); cooling water availability; ecology approximating ecology in some other solar areas; RgD facilities applicable to most solar technology; equipment immediately useful for solar energy programs; technology background in most areas of solar energy; experience with large energy systems, and background in systems analysis. From the solar energy production standpoint, the energy that falls on the 600 square miles at the Hanford site would produce 100,000 megawatts if 33 1/3% efficiency can be achieved. (MCW)n
Drumheller, K.
Comprehensive mechanisms for combustion chemistry: An experimental and numerical study with emphasis on applied sensitivity analysis. Progress report, June 15, 1990--February 1, 1993
Over the last three years, this program has made significant progress on a number of problems: development of a data base for oxidation of the CO/H{sub 2}/O{sub 2} system; development and refinement of a comprehensive kinetic mechanism for the CO/H{sub 2}/O{sub 2} system; additional experiments on formaldehyde oxidation in the, comprehensive mechanistic studies inclusive of flow reactor results and literature results from static reactors, shock tubes, and flames, and identification of elementary reactions needing further study; mechanistic study of previously acquired APFR flow reactor data on ethanol oxidation, including an estimation of the branching ratios for C{sub 2}H{sub 5}0H + X, X= OH,H and identification of elementary reactions needing additional study; completion and mechanistic evaluation of the first insitu optical diapostic measurements of OH in the APFR; determinations of uni-molecular decomposition rate for 1,3,5-Trioxane at 700 to 800 K; seeded perturbation experiments on moist CO oxidation in flow reactors as a means to determine elementary rate constants for specific reactions; determination of elementary rates for CH{sub 4} + OH {yields} CH{sub 3} + H{sub 2}0 at 1026 and 1140 K, and C{sub 3}H{sub 6} + OH {yields} products at 1020 K; First experimental studies of the H{sub 2}/O{sub 2} reaction system in the VPFR at conditions between the extended second and third explosion limits.
Numerical simulation of magma energy extraction
The Magma Energy Program is a speculative endeavor regarding practical utility of electrical power production from the thermal energy which reside in magma. The systematic investigation has identified an number of research areas which have application to the utilization of magma energy and to the field of geothermal energy. Eight topics were identified which involve thermal processes and which are areas for the application of the techniques of numerical simulation. These areas are: (1) two-phase flow of the working fluid in the wellbore, (2) thermodynamic cycles for the production of electrical power, (3) optimization of the entire system, (4) solidification and fracturing of the magma caused by the energy extraction process, (5) heat transfer and fluid flow within an open, direct-contact, heat-exchanger, (6) thermal convection in the overlying geothermal region, (7) thermal convection within the magma body, and (8) induced natural convection near the thermal energy extraction device. Modeling issues have been identified which will require systematic investigation in order to develop the most appropriate strategies for numerical simulation. It appears that numerical simulations will be of ever increasing importance to the study of geothermal processes as the size and complexity of the systems of interest increase. It is anticipated that, in the future, greater emphasis will be placed on the numerical simulation of large-scale, three-dimensional, transient, mixed convection in viscous flows and porous media. Increased computational capabilities, e.g.; massively parallel computers, will allow for the detailed study of specific processes in fractured media, non-Darcy effects in porous media, and non-Newtonian effects. 23 refs., 13 figs., 1 tab.
Hickox, C.E.
Numerical simulation of the active magnetic regenerator
A time-dependent one-dimensional model of the active magnetic regenerator (AMR) that takes into account most of the physical and practical design problems for the AMR is developed as a highly nonlinear system of partial differential equations. The adequateness ... Keywords: Active magnetic regenerator, Magnetic refrigerator, Modeling and numerical scheme, Numerical simulation, Passive regenerator
B. M. Siddikov; B. A. Wade; D. H. Schultz
Numerical Simulations of the Effects of Coastlines on the Evolution of Strong, Long-Lived Squall Lines
This study develops conceptual models of how a land�water interface affects the strength and structure of squall lines. Two-dimensional numerical simulations using the Advanced Regional Prediction System model are employed. Five sets of ...
Todd P. Lericos; Henry E. Fuelberg; Morris L. Weisman; Andrew I. Watson
Development of an instrument to measure stress among software professionals: factor analytic study
This study investigates sources of negative pressure among software professionals, from the perspective of the software development process. A multiple response questionnaire (survey instrument) was developed to measure sources of pressure among software ... Keywords: occupational stress, software professionals
K. S. Rajeswari; R. N. Anantharaman
Process development studies of the bioconversion of cellulose and production of ethanol. Semi annual report
Progress in the following process development studio is reported: economic evaluation of hydrolysis and ethanol fermentation schemes, economic evaluation of alternative fermentation processes, raw materials evaluation, and evaluation of pretreatment process. Microbiological and enzymatic studies reported are: production of cellulase enzyme from high yielding mutants, hydrolysis reactor development, xylose fermentation, and xylanese production. Fermentation and separation processes include: process development studies on vacuum fermentation and distillation, evaluation of low energy separations processes, large scale hollow fiber reactor development. (MHR)
Wilke, C.R.; Blanch, H.W.
A High-Resolution Modeling Study of the 24 May 2002 Dryline Case during IHOP. Part I: Numerical Simulation and General Evolution of the Dryline and Convection
Results from a high-resolution numerical simulation of the 24 May 2002 dryline convective initiation (CI) case are presented. The simulation uses a 400 km � 700 km domain with a 1-km horizontal resolution grid nested inside a 3-km domain and ...
Ming Xue; William J. Martin
Studies on Nuclear Reactors, Power Developed by Decay of Fissin Fragments
A study is made of the power developed by the decay of fission fragments arising during the operation of a U235 reactor.
Greenfield, M.A.
New Studies Portray Unbalanced Perspective on Biofuels DOE Committed to Environmentally Sound Biofuels Development
New Studies Portray Unbalanced Perspective on Biofuels DOE Committed to Environmentally Sound Biofuels Development DOE Response based on contributions from Office of Biomass Program; Argonne National, Hill, Tilman, Polasky and Hawthorne study ("Land Clearing and the Biofuel Carbon Debt") claims
Minnesota, University of
Preliminary Study on Sustainable Low-Carbon Development Towards 2030 in
Preliminary Study on Sustainable Low-Carbon Development Towards 2030 in Preliminary Study on Sustainable Low-Carbon Development Towards 2030 in Vietnam Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Preliminary Study on Sustainable Low-Carbon Development Towards 2030 in Vietnam Agency/Company /Organization: National Institute for Environmental Studies, Kyoto University, Asia-Pacific Integrated Model Team Sector: Energy Focus Area: Renewable Energy, Non-renewable Energy, Economic Development, Energy Efficiency, Grid Assessment and Integration, People and Policy, Solar Phase: Evaluate Options, Develop Goals, Prepare a Plan Topics: Background analysis, Implementation, Low emission development planning, -LEDS, Pathways analysis, Resource assessment Resource Type: Guide/manual, Lessons learned/best practices, Publications
Hydrogen targets for exotic-nuclei studies developed over the past 10 years
Hydrogen-induced reactions provide essential information on nuclear structure, complementary to other experimental probes. For studies at both low and relativistic incident energy, developments in hydrogen targets have been performed over the past 10 years in parallel with the development of new radioactive beams. We present a review of all major hydrogen target developments related to the study of exotic nuclei with direct reactions in inverse kinematics. Both polarized and non-polarized systems are presented.
A. Obertelli; T. Uesaka
Solid state NMR method development and studies of biological and biomimetic nanocomposites
This thesis describes application and development of advanced solid-state nuclear magnetic resonance techniques for complex materials, in particular organic-inorganic nanocomposites and thermoelectric tellurides. The apatite-collagen interface, essential for understanding the biomineralization process in bone and engineering the interface for controlled bio-mimetic synthesis and optimized mechanical properties, is buried within the nanocomposite of bone. We used multinuclear solid-state NMR to study the composition and structure of the interface. Citrate has been identified as the main organic molecule strongly bound to the apatite surface with a density of 1/(2 nm){sup 2}, covering 1/6 of the total surface area in bovine bone. Citrate provides more carboxylate groups, one of the key functional groups found to affect apatite nucleation and growth, than all the non-collagenous proteins all together in bone; thus we propose that citrate stabilizes apatite crystals at a very small thickness of {approx}3 nm (4 unit cells) to increase bone fracture tolerance. The hypothesis has been confirmed in vitro by adding citrate in the bio-mimetic synthesis of polymerhydroxyapatite nanocomposites. The results have shown that the size of hydroxyapatite nanocrystals decreases as increasing citrate concentration. With citrate concentrations comparable to that in body fluids, similar-sized nanocrystals as in bone have been produced. Besides the dimensions of the apatite crystals, the composition of bone also affects its biofunctional and macroscopic mechanical properties; therefore, our team also extended its effort to enhance the inorganic portion in our bio-mimetic synthesis from originally 15 wt% to current 50 wt% compared to 65 wt% in bovine bone, by using Lysine-Leucine hydroxyapatite nucleating diblock co-polypeptide, which forms a gel at very low concentration. In this thesis, various advanced solid state NMR techniques have been employed to characterize nanocomposites. Meanwhile, we have developed new methods to achieve broadband high resolution NMR and improve the accuracy of inter-nuclear distance measurements involving quadrupolar spins. Broadband high resolution NMR of spin-1/2 nuclei has been accomplished by the adaptation of the magic angle turning (MAT) method to fast magic angle spinning, termed fast MAT, by solving technical problems such as off resonance effects. Fast MAT separates chemical shift anisotropy and isotropic chemical shifts over a spectral range of {approx}1.8 {gamma}B{sub 1} without significant distortions. Fast MAT {sup 125}Te NMR has been applied to study technologically important telluride materials with spectra spreading up to 190 kHz. The signal-to-noise ratio of the spectra is significantly improved by using echo-matched Gaussian filtering in offline data processing. The accuracy of the measured distances between spin-1/2 and quadrupolar nuclei with methods such as SPIDER and REAPDOR has been improved by compensating for the fast longitudinal quadrupolar relaxation on the sub-millisecond with a modified S{sub 0} pulse sequence. Also, the T1Q effect on the spin coherence and its spinning speed dependency has been explored and documented with analytical and numerical simulations as well as experimental measurements.
Hu, Yanyan
Case Studies in Sustainable Development in the Coal Industry | Open Energy
Studies in Sustainable Development in the Coal Industry Studies in Sustainable Development in the Coal Industry Jump to: navigation, search Name Case Studies in Sustainable Development in the Coal Industry Agency/Company /Organization International Energy Agency Sector Energy Focus Area Conventional Energy Topics Implementation Resource Type Guide/manual, Lessons learned/best practices Website http://www.iea.org/papers/2006 Program Start 2006 References Case Studies in Sustainable Development in the Coal Industry[1] Summary "Widely held attitudes to coal's use have evolved greatly in the past five years - from those that largely dismissed a role for coal in sustainable development to a wider appreciation of coal's continuing role in providing a foundation for energy security and in meeting growing world energy
STUDY OF THE EFFECT OF PRIVATE WIRE LAWS ON DEVELOPMENT OF COMBINED STUDY OF THE EFFECT OF PRIVATE WIRE LAWS ON DEVELOPMENT OF COMBINED HEAT AND POWER FACILITIE STUDY OF THE EFFECT OF PRIVATE WIRE LAWS ON DEVELOPMENT OF COMBINED HEAT AND POWER FACILITIE Section 1308 of the Energy Independence and Security Act of 2007 ("EISA 2007") directed the Secretary of Energy, in consultation with the States, to undertake a study of the laws affecting the siting of privately-owned distribution wires on or across public rights of way and to consider the impact of those laws on the development of combined heat and power ("CHP") facilities, as well as to determine whether a change in those laws would impact utility operations, costs or reliability, or impact utility customers. The study is also to consider whether a change in those laws
Numerical Wave Modeling in Conditions with Strong Currents: Dissipation, Refraction, and Relative Wind
Currents effects on waves have led to many developments in numerical wave modeling over the past two decades, from numerical choices to parameterizations. The performance of numerical models in conditions with strong currents is reviewed here, and ...
Fabrice Ardhuin; Aron Roland; Franck Dumas; Anne-Claire Bennis; Alexei Sentchev; Philippe Forget; Judith Wolf; Fran�oise Girard; Pedro Osuna; Michel Benoit
Linear algebra operators for GPU implementation of numerical algorithms
In this work, the emphasis is on the development of strategies to realize techniques of numerical computing on the graphics chip. In particular, the focus is on the acceleration of techniques for solving sets of algebraic equations as they occur in numerical ... Keywords: graphics hardware, numerical simulation
Jens Kr�ger; R�diger Westermann
A Pilot Study to Evaluate Development Effort for High Performance Computing
1 A Pilot Study to Evaluate Development Effort for High Performance Computing Victor Basili1 the development time for programs written for high performance computers (HPC). To attack this relatively novel students in a graduate level High Performance Computing class at the University of Maryland. We collected
Assessing programming language impact on development and maintenance: a study on c and c++
Billions of dollars are spent every year for building and maintaining software. To reduce these costs we must identify the key factors that lead to better software and more productive development. One such key factor, and the focus of our paper, is the ... Keywords: developer productivity, empirical studies, high-level languages, software evolution, software quality
Pamela Bhattacharya; Iulian Neamtiu
Disruptive Innovation in Numerical Hydrodynamics
We propose the research and development of a high-fidelity hydrodynamic algorithm for tetrahedral meshes that will lead to a disruptive innovation in the numerical modeling of Laboratory problems. Our proposed innovation has the potential to reduce turnaround time by orders of magnitude relative to Advanced Simulation and Computing (ASC) codes; reduce simulation setup costs by millions of dollars per year; and effectively leverage Graphics Processing Unit (GPU) and future Exascale computing hardware. If successful, this work will lead to a dramatic leap forward in the Laboratory's quest for a predictive simulation capability.
Waltz, Jacob I. [Los Alamos National Laboratory
Guide to good practices for developing and conducting case studies: DOE handbook
Learning from experience is often very costly to a facility in terms of injured personnel, damaged equipment, and wasted time. Learning from the experience gained at the facility and from industry can prevent repeating costly mistakes. This guide contains a method for learning from experience to prevent mistakes from occurring; that method is the case study. This guide describes how to develop and present case studies. This guide provides the instructional developer insight on the best kind of case study to use and includes examples of the various types of case studies.
Numerical Methods for Optimal Stochastic Control in Finance.
??In this thesis, we develop partial differential equation (PDE) based numerical methods to solve certain optimal stochastic control problems in finance. The value of a� (more)
Chen, Zhuliang
Application of Transilient Turbulence Theory to Mesoscale Numerical Weather Forecasting
In this study we show that a unified turbulence parameterization, when divorced from the smoothing procedures needed for numerical stability of the host model, can be implemented in a numerical weather prediction model. Our host model is the 15-...
William H. Raymond; Roland B. Stull
Numerical simulation study of silica and calcite dissolution around a geothermal well by injecting high pH solutions with chelating agent.
Dissolution of silica, silicate, and calcite minerals in the presence of a chelating agent (NTA) at a high pH has been successfully performed in the laboratory using a high-temperature flow reactor. The mineral dissolution and porosity enhancement in the laboratory experiment has been reproduced by reactive transport simulation using TOUGHREACT. The chemical stimulation method has been applied by numerical modeling to a field geothermal injection well system, to investigate its effectiveness. Parameters from the quartz monzodiorite unit at the Enhanced Geothermal System (EGS) site at Desert Peak (Nevada) were used. Results indicate that the injection of a high pH chelating solution results in dissolution of both calcite and plagioclase minerals, and avoids precipitation of calcite at high temperature conditions. Consequently reservoir porosity and permeability can be enhanced especially near the injection well.
Xu, Tianfu; Rose, Peter; Fayer, Scott; Pruess, Karsten
Numerical Generation of Entropies
The spurious numerical generation and/or destruction of various types of entropies in models is investigated. It is shown that entropy s? of dry matter tends to be generated if potential temperature is advected by a damping scheme. There is no ...
Joseph Egger
Exploration and Development at Dixie Valley, Nevada- Summary of Doe Studies
at Dixie Valley, Nevada- Summary of Doe Studies at Dixie Valley, Nevada- Summary of Doe Studies Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Exploration and Development at Dixie Valley, Nevada- Summary of Doe Studies Authors David D. Blackwell, Richard P. Smith and Maria C. Richards Conference Thirty-Second Workshop on Geothermal Reservoir Engineering; Stanford University, Stanford, California; 39083 Published Thirty-Second Workshop on Geothermal Reservoir Engineering;, 2007 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Exploration and Development at Dixie Valley, Nevada- Summary of Doe Studies Citation David D. Blackwell,Richard P. Smith,Maria C. Richards. 2007. Exploration and Development at Dixie Valley, Nevada- Summary of Doe Studies. In:
Study of costs associated with alternative fuels development: A case study. Research report
The primary objective of the study was to conduct a case study of large-scale fuel conversion project to assess selected costs and related issues. An inventory of public transit agencies engaged in demonstration projects involving alternative fuels as conducted with representative sample of large public transit systems in the nation. Included in the survey were questions pertaining to fuel supply arrangements, fuel reserve storage requirements and/or deficiencies; future plans for managing energy resources and costs associated with fuel conversion/alternative fuels use -- whether planned or currently in operation. The case study approach was used to document the methodological and logistical problems encountered during the course of projects involving alternative fuels use compared with a control sample using diesel fuel. Monthly status reports on the alternative fuel project included data on accumulated mileage, road calls/unscheduled maintenance, fuel consumption, fuel cost per mile, alternative fuel purchases, schedule of activities, personnel, safety , and diesel emission test results. The data collected indicate several conclusions and future implications about technical and safety issues associated with the testing and use of liquefied natural gas (LNG).
Lede, N.W.
Electric air filtration: theory, laboratory studies, hardware development, and field evaluations
We summarize the results of a seven-year research project for the US Department of Energy (DOE) to develop electric air filters that extend the service life of high-efficiency particulate air (HEPA) filters used in the nuclear industry. This project was unique to Lawrence Livermore National Laboratory (LLNL), and it entailed comprehensive theory, laboratory studies, and hardware development. We present our work in three major areas: (1) theory of and instrumentation for filter test methods, (2) theoretical and laboratory studies of electric air filters, and (3) development and evaluation of eight experimental electric air filters.
Bergman, W.; Biermann, A.; Kuhl, W.; Lum, B.; Bogdanoff, A.; Hebard, H.; Hall, M.; Banks, D.; Mazumder, M.; Johnson, J.
PURPA Resource Development in the Pacific Northwest : Case Studies of Ten Electricity Generating Powerplants.
The case studies in this document describe the Public Utilities, Regulatory Policies Act (PURPA) development process for a variety of generating technologies. Developer interactions with regulatory agencies and power purchasers are described in some detail. Equipment, installation, and maintenance costs are identified; power marketing considerations are taken into account; and potential environmental impacts, with corresponding mitigation approaches and practices are summarized. The project development case studies were prepared by the energy agencies of the four Northwest states, under contract to the Bonneville Power Administration.
Washington State Energy Office.
Case studies of low-to-moderate temperature hydrothermal energy development
Six development projects are examined that use low- (less than 90/sup 0/C (194/sup 0/F)) to-moderate (90 to 150/sup 0/C (194 to 302/sup 0/F)) temperature geothermal resources. These projects were selected from 22 government cost-shared projects to illustrate the many facets of hydrothermal development. The case studies describe the history of this development, its exploratory methods, and its resource definition, as well as address legal, environmental, and institutional constraints. A critique of procedures used in the development is also provided and recommendations for similar future hydrothermal projects are suggested.
The Numerical Simulation of an Unbalanced Jetlet and Its Role in the Palm Sunday 1994 Tornado Outbreak in Alabama and Georgia
Meso-beta-scale numerical model simulations and observational data are synthesized in an effort to develop a multistage paradigm for use in forecasting tornadic convection in the southeastern United States. The case study to be utilized as an ...
Michael L. Kaplan; Yuh-Lang Lin; David W. Hamilton; Robert A. Rozumalski
Defining the Interactions of Cellobiohydrolase with Substrate through Structure Function Studies: Cooperative Research and Development Final Report, CRADA Number CRD-10-409
NREL researchers will use their expertise and skilled resources in numerical computational modeling to generate structure-function relationships for improved cellulase variant enzymes to support the development of cellulases with improved performance in biomass conversion.
Beckham, G. T.; Himmel, M. E.
Numerical Simulation of the Evolution of a Three-Dimensional Field of Cumulus Clouds. Part I: Model Description, Comparison with Observations and Sensitivity Studies
A surface boundary layer model was developed which utilizes the single-level surface mesonet data and the results of a surface energy and moisture budget calculation. The heat and moisture fluxes calculated using this model were employed in the ...
Piotr K. Smolarkiewicz; Terry L. Clark
Numerical models for high beta magnetohydrodynamic flow
The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs.
Brackbill, J.U.
Advanced LWR Nuclear Fuel Cladding System Development Trade-off Study |
LWR Nuclear Fuel Cladding System Development Trade-off LWR Nuclear Fuel Cladding System Development Trade-off Study Advanced LWR Nuclear Fuel Cladding System Development Trade-off Study The LWR Sustainability (LWRS) Program activities must support the timeline dictated by utility life extension decisions to demonstrate a lead test rod in a commercial reactor within 10 years. In order to maintain the demanding development schedule that must accompany this aggressive timeline, the LWRS Program focuses on advanced fuel cladding systems that retain standard UO2 fuel pellets for deployment in currently operating LWR power plants. The LWRS work scope focuses on fuel system components outside of the fuel pellet, allowing for alteration of the existing zirconium-based clad system through coatings, addition of ceramic sleeves, or complete replacement
Case Studies of Greenhouse Gas Emissions Offset Projects Implemented in the United Nations Clean Development Mechanism
This paper describes case studies of greenhouse gas (GHG) emissions offset project activities undertaken within the United Nations Clean Development Mechanism (CDM) program. This paper is designed to communicate key lessons learned from the implementation of different types of GHG emissions offsets projects in the CDM to policy makers in the U.S. who may be interested in developing national, regional or state-based GHG offsets programs. This paper also is designed to provide important insights to entitie...
Economic Development Impacts of Wind Power--Case Studies Fact Sheet
OAK-B135 Interest in wind power development is growing as a means of expanding local economies. Such development holds promise as a provider of short-term employment during facility construction and long-term employment from ongoing facility operation and maintenance (O&M). It may also add to the supply of electric power in the area and support some expansion of the local economy through ripple effects resulting from initial increases in jobs and income. These ripple effects stem from subsequent expenditures for goods and services made possible by first-round income from the development, and are expressed in terms of a multiplier. If the local economy offers a wide range of goods and services the resulting multiplier can be substantial--as much as three or four. If not, then much of the initial income will leave the local economy to buy goods and services from elsewhere. Loss of initial income to other locales is referred to as a leakage. While there is a growing body of information about the local impacts of wind power, the economic impacts from existing wind power developments have not been thoroughly and consistently analyzed. Northwest Economic Associates, under contract to the National Wind Coordinating Committee (NWCC), conducted a study and produced a report entitled ''Assessing the Economic Development Impacts of Wind Power.'' The primary objective of the study was to provide examples of appropriate analyses and documentation of economic impacts from wind power development, using case studies of three existing projects in the United States. The findings from the case studies are summarized here; more detail is available in the report, available at NWCC's website http://www.nationalwind.org/. It should be noted that specific results presented apply only to the respective locales studied and are not meant to be representative of wind power in general. However, qualitative findings, discussed below, are likely to be replicated in most areas where wind development occurs.
NWCC Economic Development Work Group
Journal of Power Sources 140 (2005) 331339 Numerical study of a flat-tube high power density solid oxide fuel cell
· Research and development in MCFC, SOFC, PEM and Fuels #12;FuelCell Energy, the FuelCell Energy logo, Direct Electrolyte Anode Cathode Electrolyte FCE SOFC Systems Background SOFC MW Module FCE utilizes VPS (Versa Power Systems) fuel cell technology in FCEs SOFC stack modules and systems. FCE/VPS team is engaged
A Quasi-Geostrophic Circulation Model of the Northeast Pacific. Part I: A Preliminary Numerical Experiment
A limited-area quasi-geostrophic numerical model with mesoscale resolution is developed to study the circulation in the northeast (NE) Pacific Ocean. The model domain extends from the British Columbia-Alaska coast out to 170�W and down to 45�N, ...
Patrick F. Cummins; Lawrence A. Mysak
A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir
Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Hydro-Thermo-Mechanical Numerical Model For Hdr Geothermal Reservoir Evaluation Details Activities (0) Areas (0) Regions (0) Abstract: A two-dimensional numerical model of coupled fluid flow, heat transfer and rock mechanics in naturally fractured rock is developed. The model is applicable to assessments of hot dry rock (HDR) geothermal reservoir characterisation experiments, and to the study of hydraulic stimulations and the heat extraction potential of HDR reservoirs. Modelling assumptions are based on the characteristics of the experimental HDR reservoir in the Carnmenellis granite in Cornwall, S. W. England. In
Hybrid Tower Study: Volume 3: Phase 3 -- Scale Model Development and Full-Scale Tests
Hybrid towers maximize the power transmission efficiency of the available space whenever there is the need to have both ac and dc lines in the same corridor. This study developed calculation techniques and design rules for the placement of conductors energized with HVAC and HVDC circuits on the same towers. Significantly, the study did not identify any hybrid interactions that would prevent the successful operation of a hybrid corridor or hybrid tower transmission line.
Review of seismicity and ground motion studies related to development of seismic design at SRS
The NRC response spectra developed in Reg. Guide 1.60 is being used in the studies related to restarting of the existing Savannah River Site (SRS) reactors. Because it envelopes all the other site specific spectra which have been developed for SRS, it provides significant conservatism in the design and analysis of the reactor systems for ground motions of this value or with these probability levels. This spectral shape is also the shape used for the design of the recently licensed Vogtle Nuclear Station, located south of the Savannah River from the SRS. This report provides a summary of the data base used to develop the design basis earthquake. This includes the seismicity, rates of occurrence, magnitudes, and attenuation relationships. A summary is provided for the studies performed and methodologies used to establish the design basis earthquake for SRS. The ground motion response spectra developed from the various studies are also summarized. The seismic hazard and PGA`s developed for other critical facilities in the region are discussed, and the SRS seismic instrumentation is presented. The programs for resolving outstanding issues are discussed and conclusions are presented.
Stephenson, D.E. [Westinghouse Savannah River Co., Aiken, SC (United States); Acree, J.R. [Westinghouse Environmental and Geotechnical Services, Inc., Columbia, SC (United States)
A Numerical Study of Three-Dimensional Gravity Waves Triggered by Deep Tropical Convection and Their Role in the Dynamics of the QBO
A 3D mesoscale model is used to study the structure of convectively triggered gravity waves in the Tropics and their role in the dynamics of the middle atmosphere. Simulations with three stratospheric background zonal wind cases are examined. In ...
C. Piani; D. Durran; M. J. Alexander; J. R. Holton
UBC Social Ecological Economic Development Studies (SEEDS) Student Report Rapidly Renewable Materials
UBC Social Ecological Economic Development Studies (SEEDS) Student Report Rapidly Renewable RAPIDLY RENEWABLE MATERIALS: WOOL AND CORK Done by: Bin Ou-Yang David Tan Ritesh Bhan #12;i ABSTRACT This report presents an investigation into the feasibility of using two rapidly renewable materials, cork
A Further Study of Comma Cloud Development in the Eastern Pacific
In a companion paper the authors presented a case study of the development of a comma-shaped cloud pattern and associated small cyclone that formed in a cold air mass over the eastern Pacific. This paper confirms the reproducibility of the ...
Richard J. Reed; Warren Blier
Development of an Online Toolkit for Measuring Commercial Building Energy Efficiency Performance -- Scoping Study
This study analyzes the market needs for building performance evaluation tools. It identifies the existing gaps and provides a roadmap for the U.S. Department of Energy (DOE) to develop a toolkit with which to optimize energy performance of a commercial building over its life cycle.
Wang, Na
The Steam Boiler Case Study: Competition of Formal Program Speci cation and Development
The Steam Boiler Case Study: Competition of Formal Program Speci#12;cation and Development Methods the design of a steam boiler control, which realizes the informal speci#12;cation handed out. The steam boiler-control speci#12;cation problem was sent out to the partici- pants nine months before
Börger, Egon
Economic Radioisotope Thermoelectric Generator (RTG) study. Volume II. Development plan. Final report
The objectives of this study were: (1) to develop and evaluate an ERTG design for a high power, Curium-244 fueled system based on the tubular thermoelectric module technology; (2) to prepare a program plan for the development of a flight qualified ERTG; and (3) to estimate the costs associated with the production of one, ten and twenty flight qualified ERTG's. This volume summarizes the program plan for developing and producing flight qualified ERTG's. The information presented explains what will be accomplished and when, in relation to the overall technical and management effort - defining a program geared to the design, development, qualification, and delivery within six years of ERTG hardware satisfying specified USAF performance objectives. In addition, cost estimates are supplied for producing ten and twenty follow-on ERTG units based on the Second Generation ERTG Design. (WHK)
Scientist-Teacher Partnerships as Professional Development: An Action Research Study
SUBMITTED AS A DOCTORAL DISSERTATION IN COMPLETION OF REQUIREMENTS FOR THE DEGREE OF ED.D THROUGH WASHINGTON STATE UNIVERSITY. The overall purpose of this action research study was to explore the experiences of ten middle school science teachers involved in a three-year partnership program between scientists and teachers at a Department of Energy national laboratory, including the impact of the program on their professional development, and to improve the partnership program by developing a set of recommendations based on the study�s findings. This action research study relied on qualitative data including field notes recorded at the summer academies and data from two focus groups with teachers and scientists. Additionally, the participating teachers submitted written reflections in science notebooks, participated in open-ended telephone interviews that were transcribed verbatim, and wrote journal summaries to the Department of Energy at the end of the summer academy. The analysis of the data, collaboratively examined by the teachers, the scientists, and the science education specialist acting as co-researchers on the project, revealed five elements critical to the success of the professional development of science teachers. First, scientist-teacher partnerships are a unique contribution to the professional development of teachers of science that is not replicated in other forms of teacher training. Second, the role of the science education specialist as a bridge between the scientists and teachers is a unique and vital one, impacting all aspects of the professional development. Third, there is a paradox for classroom teachers as they view the professional development experience from two different lenses � that of learner and that of teacher. Fourth, learning for science teachers must be designed to be constructivist in nature. Fifth, the principles of the nature of science must be explicitly showcased to be seen and understood by the classroom teacher.
Willcuts, Meredith H.
Protective Relays: Numerical Protective Relays
Protective relays are decision-making elements in the protection scheme for electrical power systems. Numerical relays offer many advantages over the traditional electromechanical types of devices. This guide provides an overview of numerical relays and discusses maintenance and testing.
Numerical Dispersion of Gravity Waves
When atmospheric gravity waves are simulated in numerical models, they are not only dispersive for physical but also for numerical reasons. Their wave properties (e.g., damping or propagation speed and direction) can depend on grid spacing as ...
Guido Schroeder; K. Heinke Schl�nzen
Analysis of the residential-energy-conservation tax credits: concepts and numerical estimates
The purposes of the study were to develop an analytical framework for examining the effects of residential energy conservation tax credits, to identify the data needed to obtain numerical analyses of these effects, and to provide numerical estimates and sensitivity analyses of these effects. Investment in both energy-saving devices and renewable energy sources is examined. The variables analyzed are: oil import savings, their time path, revenue costs to the U.S. Treasury, and the net economic welfare gain or loss. The results of the study are summarized. (MCW)
Residual Stresses and Numerical Simulation
Oct 28, 2013 ... Advances in Hydroelectric Turbine Manufacturing and Repair: Residual Stresses and Numerical Simulation Sponsored by: Metallurgical�...
Microcomputer Numerical Ocean Surface Wave Model
A numerical wean surface wave model has been developed specifically to operate on desktop super micro-computers. The model uses one or more local and moving grids within which waves of importance at a location of interest are generated. Within ...
Marshall D. Earle
A Numerical Study of the Evolving Convective Boundary Layer and Orographic Circulation around the Santa Catalina Mountains in Arizona. Part II: Interaction with Deep Convection
This is the second part of a study that examines the daytime evolution of the thermally forced boundary layer (BL) circulation over a relatively isolated mountain, about 30 km in diameter and 2 km high, and its interaction with locally initiated ...
Development and Applications Of Photosensitive Device Systems To Studies Of Biological And Organic Materials
The primary focus of the grant is the development of new x-ray detectors for biological and materials work at synchrotron sources, especially Pixel Array Detectors (PADs), and the training of students via research applications to problems in biophysics and materials science using novel x-ray methods. This Final Progress Report provides a high-level overview of the most important accomplishments. These major areas of accomplishment include: (1) Development and application of x-ray Pixel Array Detectors; (2) Development and application of methods of high pressure x-ray crystallography as applied to proteins; (3) Studies on the synthesis and structure of novel mesophase materials derived from block co-polymers.
Gruner, Sol
Improved Numerical Method for Calculation of 4-Body Transition Amplitudes
In order to study 4-body atomic collisions such as excitation-ionization, transfer with target excitation, and double electron capture, the calculation of a nine-dimensional numerical integral is often required. This calculation can become computationally expensive, especially when calculating fully differential cross sections (FDCS), where the positions and momenta of all the particles are known. We have developed a new technique for calculating FDCS using fewer computing hours, but more memory. This new technique allows for much more efficient calculations and the use of many fewer resources.
Harris, A L
Agua Caliente Solar Feasibility and Pre-Development Study Final Report
Evaluation of facility- and commercial-scale solar energy projects on the Agua Caliente Band of Cahuilla Indians Reservation in Palm Springs, CA. The Agua Caliente Band of Cahuilla Indians (ACBCI) conducted a feasibility and pre-development study of potential solar projects on its lands in southern California. As described below, this study as a logical and necessary next step for ACBCI. Support for solar project development in California, provided through the statewide California Solar Initiative (CSI), its Renewable Portfolio Standard and Feed-in Tariff Program, and recently announced Reverse Auction Mechanism, provide unprecedented support and incentives that can be utilized by customers of California's investor-owned utilities. Department of Energy (DOE) Tribal Energy Program funding allowed ACBCI to complete its next logical step to implement its Strategic Energy Plan, consistent with its energy and sustainability goals.
Carolyn T. Stewart, Managing Partner; Red Mountain Energy Partners
ToHajiilee Economic Development, Inc.(TEDI) Feasibility Study for Utility-Scale Solar
To�?�?Hajiilee Economic Development, Inc. (TEDI) is the economic development entity representing the ToHajiilee Chapter of the Navajo Nation, also known as the Ca�?�?oncito Band of Navajo (CBN). Using DOE funding, TEDI assembled a team of qualified advisors to conduct a feasibility study for a utility-scale 30 MW Photovoltaic (PV) solar power generation facility on TEDI trust lands. The goal for this project has been to gather information and practical business commitments to successfully complete the feasibility analysis. The TEDI approach was to successively make informed decisions to select an appropriate technology best suited to the site, determine environmental viability of the site, secure options for the sale of generated power, determine practicality of transmission and interconnection of power to the local grid, and secure preliminary commitments on project financing. The feasibility study has been completed and provides TEDI with a practical understanding of its business options in moving forward with developing a solar project on CBN tribal lands. Funding from DOE has allowed TEDI and its team of professional advisors to carefully select technology and business partners and build a business model to develop this utility-scale solar project. As a result of the positive feasibility findings, TEDI is moving forward with finalizing all pre-construction activities for its major renewable energy project.
Burpo, Rob
Development and application of photosensitive device systems to studies of biological and organic materials
This report discusses the following basic research accomplishments: new x-ray structure determination methods were developed and applied to biomembrane lipid phases; a novel mechanism for general anesthesia was proposed; the elastic properties of membranes were investigated, both theoretically and experimentally; the effects of high pressures on membranes were studied; neutron diffraction was used to probe mesophase structure; and novel lipid and surfactant systems are characterized. Also discussed are instrumentation accomplishments.
Gruner, S.M.; Reynolds, G.T.
Develop nickel--zinc battery suitable for electric vehicle propulsion. Task A: design and cost study
A three-month design and cost study for the use of nickel--zinc batteries in electric vehicles is presented. Battery configuration is analyzed, and expected performance is set forth. Current development problems concern component materials and capacity decline on cycling, electrolyte maintenance, and thermal characteristics. The manufacturing process is outlined, and estimates are made for cost, materials requirements, capital needs, etc. 61 figures, 24 tables. (RWR)
Hybrid Transmission Corridor Study: Volume 1: Phase 1--Scale Model Development
Installation of HVDC transmission lines on existing rights- of-way with HVAC lines can increase power transfer for a given right-of-way width. This phase of the hybrid transmission corridor study developed a model for predicting the electrical effects between HVAC and HVDC lines in a hybrid corridor. The work underscores the importance of maintaining a critical separation between the two lines.
numerical modeling | OpenEI Community
07 07 Varnish cache server Home Groups Community Central Green Button Applications Developer Utility Rate FRED: FRee Energy Database More Public Groups Private Groups Features Groups Blog posts Content Stream Documents Discussions Polls Q & A Events Notices My stuff Energy blogs 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142233807 Varnish cache server numerical modeling Home Ocop's picture Submitted by Ocop(5) Member 18 April, 2013 - 13:41 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing claims of LCOE, DOE has developed-for its own use-a standardized cost and performance data reporting process to facilitate uniform calculation of LCOE from MHK device developers. This
Market definition study of photovoltaic power for remote villages in developing countries
The objective of this market definition study is to assess the market potential for the use of photovoltaic power systems for remote villages in developing countries. The approach used was to conduct an in-depth literature search followed by in-country surveys of selected developing countries in Africa, the Middle East, Southeast Asia, and Latin America. The purpose of these surveys was to determine the current energy situation in these countries, the level of rural electrification activity, their knowledge and interest in solar and specifically photovoltaics, their financial resource capability, and the probability of development of a market for photovoltaics based on these and other factors. Findings are presented. The conclusion reached by the survey is that there is a significant market potential for photovoltaics in village power applications in developing countries. Extrapolation of the number of unelectrified villages results in an estimated potential of as much as 20,000 MWp, a potential similar in magnitude to previous UN and World Bank estimates. Recommendations for market stimulation are presented. (WHK)
Ragsdale, C.; Quashie, P.
Numerical simulation of thermal response of the skin tissues
The aim of this paper is to develop a numerical model for the simulation the heat transfer process and the heat-induced mechanical response of the skin tissues. We present some models using the finite element method in 2D space. A multilayer model is ... Keywords: biothermomechanics, coupled problems, finite element method, numerical methods, skin tissue, thermal systems
Iulia Maria C�rstea; Ion C�rstea
Robust Numerical Integration Using Wave-Digital Concepts
Numerical integration of linear and nonlinear ordinary and partial differential equations describing physically realistic systems can be achieved by means of principles derived from those originally developed in the context of wave digital filters, thus ... Keywords: Robust numerical integration, linear and nonlinear ordinary and partial differential equations, multidimensional causal and passive systems, wave-digital approach
Alfred Fettweis
Numerical simulations of oblique penetration into reinforced concrete targets
A dynamic constitutive model based on the tensile and the compressive damage models for concrete was developed and implemented into the three-dimensional finite element code, LS-DYNA. Numerical simulations of oblique penetration into reinforced concrete ... Keywords: Dynamic damage model, Numerical simulation, Oblique penetration, Reinforced concrete
Yan Liu; Fenglei Huang; Aie Ma
Numerical Evaluation of Special Functions
... Series of Numerical Mathematics, vol. 112, Birkh�user Verlag, Basel, 1993, pp. 111--130. Gau93b W. Gautschi, On the ...
Numerical Modeling | Open Energy Information
Numerical Modeling Numerical Modeling Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Numerical Modeling Details Activities (8) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Data and Modeling Techniques Exploration Sub Group: Modeling Techniques Parent Exploration Technique: Modeling Techniques Information Provided by Technique Lithology: Stratigraphic/Structural: Stress fields and magnitudes Hydrological: Visualization and prediction of the flow patterns and characteristics of geothermal fluids Thermal: Thermal conduction and convection patterns in the subsurface Dictionary.png Numerical Modeling: A computer model that is designed to simulate and reproduce the mechanisms of a particular system. Other definitions:Wikipedia Reegle
Environmental concerns influencing the future development of energy material transportation systems: the year 2000 study
This paper presents results of studies conducted to assess the potentially longer-range problems which could hinder the future development of safe and environmentally-acceptable energy material transportation systems. The purpose of this effort is to recommend appropriate action that contributes to the anticipatory management of possible future problems before they can have serious effects on the adequacy or acceptability of the system. Most significant future concerns in energy material transportation relate to potential institutional, legal, political and social problems. Environmental issues are involved in many of these concerns. Selected environmental concerns are discussed that may influence the future development of transportation systems for fossil and nuclear energy materials during the balance of this century. A distinction between potentially real and perceived concerns is made to emphasize basic differences in the recommended approach to solutions of the respective type of potential problem.
DeSteese, J. G.
Cloud Interactions and Merging: Numerical Simulations
A total of 48 numerical experiments have been performed to study cloud interactions and merging by means of a two-dimensional multi-cell model. Two soundings of deep convection during GATE and two different magnitudes of large-scale lifting.have ...
Wei-Kuo Tao; Joanne Simpson
Numerical Simulations of the Wake of Kauai
This study uses a series of numerical simulations to examine the structure of the wake of the Hawaiian island of Kauai. The primary focus is on the conditions on 26 June 2003, which was the day of the demise of the Helios aircraft within Kauai�s ...
Todd P. Lane; Robert D. Sharman; Rod G. Frehlich; John M. Brown
Mercury Speciation in Coal-Fired Power Plant Flue Gas-Experimental Studies and Model Development
The overall goal of the project was to obtain a fundamental understanding of the catalytic reactions that are promoted by solid surfaces present in coal combustion systems and develop a mathematical model that described key phenomena responsible for the fate of mercury in coal-combustion systems. This objective was achieved by carefully combining laboratory studies under realistic process conditions using simulated flue gas with mathematical modeling efforts. Laboratory-scale studies were performed to understand the fundamental aspects of chemical reactions between flue gas constituents and solid surfaces present in the fly ash and their impact on mercury speciation. Process models were developed to account for heterogeneous reactions because of the presence of fly ash as well as the deliberate addition of particles to promote Hg oxidation and adsorption. Quantum modeling was used to obtain estimates of the kinetics of heterogeneous reactions. Based on the initial findings of this study, additional work was performed to ascertain the potential of using inexpensive inorganic sorbents to control mercury emissions from coal-fired power plants without adverse impact on the salability fly ash, which is one of the major drawbacks of current control technologies based on activated carbon.
Radisav Vidic; Joseph Flora; Eric Borguet
Study and Development of Anti-Islanding Control for Synchronous Machine-Based Distributed Generators: November 2001--March 2004
This report summarizes the study and development of new active anti-islanding control schemes for synchronous machine-based distributed generators, including engine generators and gas turbines.
Ye, Z.
Carbon emissions and sequestration in forests: Case studies from seven developing countries. Volume 1, Summary: Draft
Forests are a major source of carbon dioxide emissions in developing countries, in most cases far exceeding the emissions from the energy sector. To date, however, efforts at quantifying forestry emissions have produced a wide range of results. In order to assist policymakers in developing measures to reduce emissions` levels and to increase carbon sequestration, the Tropical Forest Research Network (F-7) has undertaken this effort to improve the precision of emissions estimates and to identify possible response options in the forestry sector. This paper summarizes the results of one component of this work. The Tropical Forest Research Network (F-7) was established in 1990 as part of the Intergovernmental Panel on Climate Change`s (IPCC) activities in examining growing emissions of greenhouse gases and their potential impact on the global climate. Unlike past methods, this study relied on a network of participants from developing countries to prepare estimates of carbon emissions. The participating countries -- Brazil, China, India, Indonesia, Malaysia, Mexico and Thailand -- currently represent an estimated two-thirds of the annual deforestation of closed moist forests. This study gives an estimate of 837 million tonnes of carbon emissions from deforestation and logging in the F-7 countries in 1990. A proportional projection of these estimates to the tropical biome shows that the total carbon emissions are between 1.1 and 1.7 billion tonnes of carbon, with a working average of 1.4 billion tonnes per year. This work also provides estimates of emissions and uptake from China, which past studies rarely have included. This summary will be followed by individual reports by each of the participating countries, which will include detailed evaluations of possible response options. Estimates for Nigeria are also under preparation.
Makundi, W.; Sathaye, J. [eds.; Cerutti, O.M.
Carbon emissions and sequestration in forests: Case studies from seven developing countries
Forests are a major source of carbon dioxide emissions in developing countries, in most cases far exceeding the emissions from the energy sector. To date, however, efforts at quantifying forestry emissions have produced a wide range of results. In order to assist policymakers in developing measures to reduce emissions' levels and to increase carbon sequestration, the Tropical Forest Research Network (F-7) has undertaken this effort to improve the precision of emissions estimates and to identify possible response options in the forestry sector. This paper summarizes the results of one component of this work. The Tropical Forest Research Network (F-7) was established in 1990 as part of the Intergovernmental Panel on Climate Change's (IPCC) activities in examining growing emissions of greenhouse gases and their potential impact on the global climate. Unlike past methods, this study relied on a network of participants from developing countries to prepare estimates of carbon emissions. The participating countries -- Brazil, China, India, Indonesia, Malaysia, Mexico and Thailand -- currently represent an estimated two-thirds of the annual deforestation of closed moist forests. This study gives an estimate of 837 million tonnes of carbon emissions from deforestation and logging in the F-7 countries in 1990. A proportional projection of these estimates to the tropical biome shows that the total carbon emissions are between 1.1 and 1.7 billion tonnes of carbon, with a working average of 1.4 billion tonnes per year. This work also provides estimates of emissions and uptake from China, which past studies rarely have included. This summary will be followed by individual reports by each of the participating countries, which will include detailed evaluations of possible response options. Estimates for Nigeria are also under preparation.
Makundi, W.; Sathaye, J. (eds.); Cerutti, O.M.
Problem definition study of subsidence caused by geopressured geothermal resource development
The environmental and socio-economic settings of four environmentally representative Gulf Coast geopressured geothermal fairways were inventoried. Subsidence predictions were prepared using feasible development scenarios for the four representative subsidence sites. Based on the results of the subsidence estimates, an assessment of the associated potential environmental and socioeconomic impacts was prepared. An inventory of mitigation measures was also compiled. Results of the subsidence estimates and impact assessments are presented, as well as conclusions as to what are the major uncertainties, problems, and issues concerning the future study of geopressured geothermal subsidence.
Design and Analysis of Numerical Experiments
Calculations with numerical models are often referred to as numerical experiments, by analogy to classical laboratory experiments. Usually, many numerical experiments are carried out to determine the response of a numerical model to variations of ...
Kenneth P. Bowman; Jerome Sacks; Yue-Fang Chang
The development of a micropatterned electrode for studies of zinc electrodeposition
A micropatterned electrode was prepared for the study of electrocrystallization. Using microphotolithography, in conjunction with evaporation and pulse electrodeposition of thin films, a set of artificially roughened electrodes with hemispherical surface features five microns in diameter was developed. Voltammetric studies were conducted to determine the best electrode material. Gold, platinum, and various carbon surfaces were evaluated for zinc nucleation density and hydrogen overpotential. Surface homogeneity was examined by both light and scanning electron microscopy. Gold was determined to possess the best combination of material properties: chemical inertness, low melting point, and a high work function allowing underpotential deposition of zinc which reduces the rate of hydrogen evolution. Stripping coulometry was employed to determine zinc limiting currents, and evaluate effective diffusion coefficients in concentrated zinc chloride solutions. Although the method worked well for dilute zinc chloride and copper sulfate solutions, it failed at higher current densities; the emergence of surface roughness obscured actual limiting current plateaus.
Sutija, D.P.; Muller, R.H.; Tobias, C.W.
Study and program plan for improved heavy duty gas turbine engine ceramic component development
A five-year program plan was generated from the study activities with the objectives of demonstrating a fuel economy of 213 mg/W . h (0.35 lb/hp-hr) brake specific fuel consumption by 1981 through use of ceramic materials, with conformance to current and projected Federal noise and emission standards, and to demonstrate a commercially viable engine. Study results show that increased turbine inlet and regenerator inlet temperatures, through the use of ceramic materials, contribute the greatest amount to achieving fuel economy goals. Further, improved component efficiencies (for the compressor, gasifier turbine, power turbine, and regenerator disks show significant additional gains in fuel economy. Fuel saved in a 500,000-mile engine life, risk levels involved in development, and engine-related life cycle costs for fleets (100 units) of trucks and buses were used as criteria to select work goals for the planned program.
Helms, H.E.
Renewable Energy Feasibility Study Leading to Development of the Native Spirit Solar Energy Facility
DOE-funded renewable energy feasibility study conducted by Red Mountain Tribal Energy on behalf of the Southwest Tribal Energy Consortium (SWTEC). During the course of the study, SWTEC members considered multiple options for the organization structure, selected a proposed organization structure, and drafted a Memorandum of Understanding for the SWTEC organization. High-level resource assessments for SWTEC members were completed; surveys were developed and completed to determine each member�s interest in multiple participation options, including on-reservation projects. With the survey inputs in mind, multiple energy project options were identified and evaluated on a high-level basis. That process led to a narrowing of the field of technology options to solar generation, specifically, utility-scale Concentrating Solar-Powered Generation projects, with a specific, tentative project location identified at the Fort Mojave Indian Reservation -- the Native Spirit Solar Energy Facility.
Carolyn Stewart; Tracey LeBeau
Method for Developing Descriptions of Hard-to-Price Products: Results of the Telecommunications Product Study
This report presents the results of a study to test a new method for developing descriptions of hard-to-price products. The Bureau of Labor Statistics (BLS) is responsible for collecting data to estimate price indices such as the Consumers Price Index (BLS) is responsible for collecting data to estimate price indices such as the Consumers Price Index (CPI). BLS accomplishes this task by sending field staff to places of business to price actual products. The field staff are given product checklists to help them determine whether products found today are comparable to products priced the previous month. Prices for non-comparable products are not included in the current month's price index calculations. A serious problem facing BLS is developing product checklists for dynamic product areas, new industries, and the service sector. It is difficult to keep checklists up-to-date and quite often simply to develop checklists for service industry products. Some people estimates that upwards of 50 % of US economic activity is not accounted for in the CPI
Conrad, F.; Tonn, B.
Development of an entrained flow gasifier model for process optimization study
Coal gasification is a versatile process to convert a solid fuel in syngas, which can be further converted and separated in hydrogen, which is a valuable and environmentally acceptable energy carrier. Different technologies (fixed beds, fluidized beds, entrained flow reactors) are used, operating under different conditions of temperature, pressure, and residence time. Process studies should be performed for defining the best plant configurations and operating conditions. Although 'gasification models' can be found in the literature simulating equilibrium reactors, a more detailed approach is required for process analysis and optimization procedures. In this work, a gasifier model is developed by using AspenPlus as a tool to be implemented in a comprehensive process model for the production of hydrogen via coal gasification. It is developed as a multizonal model by interconnecting each step of gasification (preheating, devolatilization, combustion, gasification, quench) according to the reactor configuration, that is in entrained flow reactor. The model removes the hypothesis of equilibrium by introducing the kinetics of all steps and solves the heat balance by relating the gasification temperature to the operating conditions. The model allows to predict the syngas composition as well as quantity the heat recovery (for calculating the plant efficiency), 'byproducts', and residual char. Finally, in view of future works, the development of a 'gasifier model' instead of a 'gasification model' will allow different reactor configurations to be compared.
Biagini, E.; Bardi, A.; Pannocchia, G.; Tognotti, L. [Consorzio Pisa Ric, Pisa (Italy). Div Energia Ambiente
Numerical Experiments in Mesoscale Prediction over Southeast Australia
A new movable fine-mesh model (MFM) developed at the Australian Numerical Meteorology Research Centre, for mesoscale data assimilation and forecasting, is described. For the present, it is a 10-layer, hydrostatic, primitive equations model with ...
D. J. Gauntlett; L. M. Leslie; L. W. Logan
Linear Spectral Numerical Model for Internal Gravity Wave Propagation
A three-dimensional linear spectral numerical model is proposed to simulate the propagation of internal gravity wave fluctuations in a stably stratified atmosphere. The model is developed to get first-order estimations of gravity wave ...
J. Marty; F. Dalaudier
The Fleet Numerical Oceanography Center Global Spectral Ocean Wave Model
The Spectral Ocean Wave Model (SOWM) has been an operational product at Fleet Numerical Oceanography Center since the mid 1970s; the Global Spectral Ocean Wave Model (GSOWM) was developed to replace it. An operational test of GSOWM, using buoy, ...
R. M. Clancy; J. E. Kaitala; L. F. Zambresky
Using Radar Wind Observations to Improve Mesoscale Numerical Weather Prediction
A high-resolution radar data assimilation system is presented for high-resolution numerical weather prediction models. The system is under development at the Naval Research Laboratory for the Navy�s Coupled Ocean�Atmosphere Mesoscale Prediction ...
Qingyun Zhao; John Cook; Qin Xu; Paul R. Harasti
A Numerical Model for Low-Frequency Equatorial Dynamics
A fast, efficient numerical procedure for modeling the linear low-frequency motions on an equatorial beta plane is developed. The model is capable of simulating the seasonal and interannual variability in realistically shaped ocean basins forced ...
Mark A. Cane; Randall J. Patton
The career development of successful Hispanic administrators in higher education: a Delphi study
The purpose of this study was twofold: (1) to identify the successful experiences and strategies implemented by Hispanic administrators who have a successful career in higher education and (2) to take a futuristic look at the careers of Hispanic administrators in higher education by identifying recommendations and strategies proposed by a panel of successful Hispanic administrators to help Hispanics in the future. To focus on the career development of Hispanic administrators, a Delphi panel of 11 administrators who serve in the role of Vice-Presidents, Presidents and Chancellors from across the country was utilized. This research used a computer-based Delphi technique. A portion of the three-round study was sponsored by the Center for Distance Learning Research (CDLR) at Texas A&M University. The first round was open-ended. Panelists were asked to answer four research questions. Those items were then put into common themes and sent out for rankings on a 4 point Likert scale for Round 2. Panelists were also given another opportunity to add items to the list during Round 2. Round 3 asked panelists to review their rankings, group rankings and standard deviations. Then they were given an opportunity to change their rankings or keep them the same. Panelists also ranked items that were added during Round 2. A consensus was established on items that were rated either a 3 (agree) or a 4 (strongly agree) by all panelists. Through this study, a total of 48 items met consensus on the four research questions. Many of the items that met consensus addressed the need of inter- and intrapersonal skills as well as leadership abilities. Among the highest ranking items were obtaining a doctoral degree, personal motivation, ability to work with others, communication skills and people skills. Among the recommendations, based on the consensus items, are the creation of a University Minority Graduate Identification Program and the development of an Executive Leadership Program for Minorities.
Silva, Rito , Jr.
Subtask 2.2 - Creating A Numerical Technique for Microseismic Data Inversion
Geomechanical and geophysical monitoring are the techniques which can complement each other and provide enhancement in the solutions of many problems of geotechnical engineering. One of the most promising geophysical techniques is passive seismic monitoring. The essence of the technique is recording the acoustic signals produced in the subsurface, either naturally or in response to human activity. The acoustic signals are produced by mechanical displacements on the contacts of structural elements (e.g., faults, boundaries of rock blocks, natural and induced fractures). The process can be modeled by modern numerical techniques developed in geomechanics. The report discusses a study that was aimed at the unification of the passive seismic monitoring and numerical modeling for the monitoring of the hydraulic fracture propagation. The approach adopted in the study consisted of numerical modeling of the seismicity accompanying hydraulic fracture propagation and defining seismic attributes and patterns characterizing the process and fracture parameters. Numerical experiments indicated that the spatial distribution of seismic events is correlated to geometrical parameters of hydrofracture. Namely, the highest density of the events is observed along fracture contour, and projection of the events to the fracture plane makes this effect most pronounced. The numerical experiments also showed that dividing the totality of the events into groups corresponding to the steps of fracture propagation allows for reconstructing the geometry of the resulting fracture more accurately than has been done in the majority of commercial applications.
Anastasia Dobroskok; Yevhen Holubnyak; James Sorensen
Numerical tests of dynamical friction in gravitational inhomogeneous systems
In this paper, I test by numerical simulations the results of Del Popolo & Gambera (1998),dealing with the extension of Chandrasekhar and von Neumann's analysis of the statistics of the gravitational field to systems in which particles (e.g., stars, galaxies) are inhomogeneously distributed. The paper is an extension of that of Ahmad & Cohen (1974), in which the authors tested some results of the stochastic theory of dynamical friction developed by Chandrasekhar & von Neumann (1943) in the case of homogeneous gravitational systems. It is also a continuation of the work developed in Del Popolo (1996a,b), which extended the results of Ahmad & Cohen (1973), (dealing with the study of the probability distribution of the stochastic force in homogeneous gravitational systems) to inhomogeneous gravitational systems. Similarly to what was done by Ahmad & Cohen (1974) in the case of homogeneous systems, I test, by means of the evolution of an inhomogeneous system of particles, that the theoretical ...
Popolo, A D
Nondestructive Testing of Overhead Transmission Lines: Numerical and Experimental Investigation
Overhead transmission lines are periodically inspected using both on-ground and helicopter-aided visual inspection. Factors including sun glare, cloud cover, close proximity to power lines and the rapidly changing visual circumstances make airborne inspection of power lines a particularly hazardous task. In this research, a finite element model is developed that can be used to create the theoretical dispersion curves of an overhead transmission line. The complex geometry of the overhead transmission line is the primary reason for absence of a theoretical solution to get the analytical dispersion curves. The numerical results are then verified with experimental tests using a non-contact and broadband laser detection technique. The methodology developed in this study can be further extended to a continuous monitoring system and be applied to other cable monitoring applications, such as bridge cable monitoring, which would otherwise put human inspectors at risk.
Kulkarni, Salil Subhash
Architectural mediators : a study of the relationship between architects and developers
This thesis contains basic understanding of the roles of the architect and the developer in t he American real estate industry. The thesis concluded that roles the architect and the developer play in the development process ...
Lin, Susan C. (Susan Chu)
Numerical Models of Boundary Layer Processes over and around the Gulf of Mexico during a Return-Flow Event
The return-flow of low-level air from the Gulf of Mexico over the southeast United States during the cool season is studied using numerical models. The key models are a newly developed airmass transformation (AMT) model and a one-dimensional ...
A. Birol Kara; James B. Elsner; Paul H. Ruscher
The Momotombo Geothermal Field, Nicaragua: Exploration and development case history study
This case history discusses the exploration methods used at the Momotombo Geothermal Field in western Nicaragua, and evaluates their contributions to the development of the geothermal field models. Subsequent reservoir engineering has not been synthesized or evaluated. A geothermal exploration program was started in Nicaragua in 1966 to discover and delineate potential geothermal reservoirs in western Nicaragua. Exploration began at the Momotombo field in 1970 using geological, geochemical, and geophysical methods. A regional study of thermal manifestations was undertaken and the area on the southern flank of Volcan Momotombo was chosen for more detailed investigation. Subsequent exploration by various consultants produced a number of geotechnical reports on the geology, geophysics, and geochemistry of the field as well as describing production well drilling. Geological investigations at Momotombo included photogeology, field mapping, binocular microscope examination of cuttings, and drillhole correlations. Among the geophysical techniques used to investigate the field sub-structure were: Schlumberger and electromagnetic soundings, dipole mapping and audio-magnetotelluric surveys, gravity and magnetic measurements, frequency domain soundings, self-potential surveys, and subsurface temperature determinations. The geochemical program analyzed the thermal fluids of the surface and in the wells. This report presents the description and results of exploration methods used during the investigative stages of the Momotombo Geothermal Field. A conceptual model of the geothermal field was drawn from the information available at each exploration phase. The exploration methods have been evaluated with respect to their contributions to the understanding of the field and their utilization in planning further development. Our principal finding is that data developed at each stage were not sufficiently integrated to guide further work at the field, causing inefficient use of resources.
Science/art - art/science: case studies of the development of a professional art product
Objective was to follow the cognitive and creative processes demonstrated by student research participants as they integrated a developing knowledge of ``big`` science, as practiced at LLNL, into a personal and idiosyncratic visual, graphical, or multimedia product. The participants, all non-scientists, involved in this process, attended a series of design classes, sponsored by LLNL at the Art Center College of Design in Pasadena CA. As a result of this study, we have become interested in the possibility of similar characteristics between scientists and artists. We have also become interested in the different processes that can be used to teach science to non-scientists, so that they are able to understand and portray scientific information.
Sesko, S.C.; Marchant, M.
DOE-HDBK-1116-98; Guide to Good Practices for Developing and Conducting Case Studies
6-98 6-98 January 1998 Superseding DOE-STD-1058-93 DOE HANDBOOK GUIDE TO GOOD PRACTICES FOR DEVELOPING AND CONDUCTING CASE STUDIES U.S. Department of Energy AREA TRNG Washington, D.C. 20585 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831; (423) 576-8401. Available to the public from the U.S. Department of Commerce, Technology Administration, National Technical Information Service, Springfield, VA 22161; (703) 605-6000. Order No. DE98001291 DOE-HDBK-1116-98 iii FOREWORD 1. This Department of Energy (DOE) Handbook is approved for use by all DOE Components
Simulation study to investigate development options for a super-heavy oil reservoir
A reservoir simulation study was performed on a heavy oil reservoir with the main objective of evaluating possible development options beyond the existing cold production method. The 206-acre area simulated - part of a significantly larger oil accumulation - lies about 3000 ft. ss. and has a gross thickness of 560 ft. The simulated area contains 120 MMSTB oil of 9� API gravity with in situ viscosity of 6,000 cp. Production began in 1992 with the reservoir being drained by one vertical well, one slanted well and one horizontal well. The simulation study was conducted in a systematic manner using two types of commercial reservoir simulators to minimize computational time. For history matching the cold production period and forecasting of cold production cases, a black oil simulator was used (ECLIPSE 100). A fairly satisfactory match of the production and pressure data was obtained which required an analytical aquifer to be attached to the northern part of the reservoir. For thermal EOR cases, the oil was simulated as a hydrocarbon consisting of three pseudo components. These cases were run using a thermal compositional simulator (ECLIPSE 300). Simulation results indicate oil recovery, for the area developed by the existing horizontal well and two new horizontal wells, to be as follows. For cold production, the oil recovery amounts to 13% of original-oil-in-place (OOIP). With cyclic steam injection, the recovery factor is slightly increased to 15% OOIP. However, with steam flooding -utilizing the new horizontal wells as injectors - the recovery factor is significantly increased to 22% OOIP. Steam flooding is evidently superior to cyclic steam injection primarily due to the fact that the reservoir is pressurized in the former EOR method and not in the latter, and to the fact that cyclic steam injection is more a near-wellbore thermal stimulation process as opposed to a more reservoir-wide heating process under steam flooding. Finally, with steam-propane injection (at a constant steam:propane mass ratio of 100:5), the oil recovery factor is further increased to 26% OOIP. Simulation results indicate this EOR method creates a more favorable distribution of heat in the reservoir, thus better sweep efficiency and reduction in produced water cut. Selection of development options to be implemented would depend on the economics of each case. Economic evaluation of the various cases has not been covered in the thesis and is best done by the operator of the field.
Diaz Franco, Jose Manuel
Development of a Mesh Generation Code with a Graphical Front-End: A Case Study
Scientists and engineers are increasingly developing software to enable them to do their work. A number of characteristics differentiate the software development environment in which a scientist or engineer works from the development environment in which ... Keywords: Computational Engineering, Lessons Learned, Mesh-generation Code, Software Development, Software Engineering
Jeffrey Carver
Numerical Modeling of the Nucleation Conditions of Petal-Centerline
the Nucleation Conditions of Petal-Centerline the Nucleation Conditions of Petal-Centerline Fractures below a Borehole Floor, A Sensitivity Study and Application to the Coso Geothermal Field Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Numerical Modeling of the Nucleation Conditions of Petal-Centerline Fractures below a Borehole Floor, A Sensitivity Study and Application to the Coso Geothermal Field Details Activities (1) Areas (1) Regions (0) Abstract: A boundary element model using Poly3D© has been developed to investigate the conditions in which the stress concentration below the floor of a borehole can cause tensile stress necessary to nucleate petal-centerline fractures. The remote stress state, borehole geometry, and traction boundary conditions on the borehole surface are taken from direct
Development of laboratory studies on the off-gassing of wood pellets
In the present study three sealed containers (304.8 mm inside diameter and 609.6 mm height) were developed to investigate the concentration of off-gases accumulated in the headspace as well as changes in some of the physical properties of wood pellets during storage. Pellets occupied 75% of the container volume leaving 25% headspace. The outside wall of the steel containers was wrapped with electric heating tapes and fiber glass insulation. The storage studies were carried out at room temperature of about 22 degrees C and at elevated temperatures of 30, 40 and 50 degrees C. The off-gases were collected and analyzed using micro gas chromatography. The accumulations of CO (5000 ppmv) and CO2 (10000 ppmv) were relatively high at room temperature of about 22 degrees C for a storage period of 24 days. These accumulations increased sharply at storage temperatures greather than 30 degrees C. At 50 degrees C, the maximum measured concentration of CO, CO2 and CH4 was about17,000, 70,000 and 3,000 ppmv, respectively. Storage temperature had a significanteffect (PB0.01) on all of the pellet properties, including pellet durability, which dropped by about 20% at the end of 60 days of storage.
Jaya Shankar Tumuluru; Xingya Kuang; Shahab Sokhansanj; C. Jim Lim; Tony Bi; Staffan Melin
study the production, distribution, and consumption of food, fiber, and energy in both developed and improving government policy, market performance, environmental quality, the efficiency of natural resource professional competence in a topical and a regional specialization and in Geographical Information System
Hammock, Bruce D.
ForCent model development and testing using the Enriched Background Isotope Study experiment
The ForCent forest ecosystem model was developed by making major revisions to the DayCent model including: (1) adding a humus organic pool, (2) incorporating a detailed root growth model, and (3) including plant phenological growth patterns. Observed plant production and soil respiration data from 1993 to 2000 were used to demonstrate that the ForCent model could accurately simulate ecosystem carbon dynamics for the Oak Ridge National Laboratory deciduous forest. A comparison of ForCent versus observed soil pool {sup 14}C signature ({Delta} {sup 14}C) data from the Enriched Background Isotope Study {sup 14}C experiment (1999-2006) shows that the model correctly simulates the temporal dynamics of the {sup 14}C label as it moved from the surface litter and roots into the mineral soil organic matter pools. ForCent model validation was performed by comparing the observed Enriched Background Isotope Study experimental data with simulated live and dead root biomass {Delta} {sup 14}C data, and with soil respiration {Delta} {sup 14}C (mineral soil, humus layer, leaf litter layer, and total soil respiration) data. Results show that the model correctly simulates the impact of the Enriched Background Isotope Study {sup 14}C experimental treatments on soil respiration {Delta} {sup 14}C values for the different soil organic matter pools. Model results suggest that a two-pool root growth model correctly represents root carbon dynamics and inputs to the soil. The model fitting process and sensitivity analysis exposed uncertainty in our estimates of the fraction of mineral soil in the slow and passive pools, dissolved organic carbon flux out of the litter layer into the mineral soil, and mixing of the humus layer into the mineral soil layer.
Parton, W.J.; Hanson, P. J.; Swanston, C.; Torn, M.; Trumbore, S. E.; Riley, W.; Kelly, R.
Powder River Basin Coalbed Methane Development and Produced Water Management Study
Coalbed methane resources throughout the entire Powder River Basin were reviewed in this analysis. The study was conducted at the township level, and as with all assessments conducted at such a broad level, readers must recognize and understand the limitations and appropriate use of the results. Raw and derived data provided in this report will not generally apply to any specific location. The coal geology in the basin is complex, which makes correlation with individual seams difficult at times. Although more than 12,000 wells have been drilled to date, large areas of the Powder River Basin remain relatively undeveloped. The lack of data obviously introduces uncertainty and increases variability. Proxies and analogs were used in the analysis out of necessity, though these were always based on sound reasoning. Future development in the basin will make new data and interpretations available, which will lead to a more complete description of the coals and their fluid flow properties, and refined estimates of natural gas and water production rates and cumulative recoveries. Throughout the course of the study, critical data assumptions and relationships regarding gas content, methane adsorption isotherms, and reservoir pressure were the topics of much discussion with reviewers. A summary of these discussion topics is provided as an appendix. Water influx was not modeled although it is acknowledged that this phenomenon may occur in some settings. As with any resource assessment, technical and economic results are the product of the assumptions and methodology used. In this study, key assumptions as well as cost and price data, and economic parameters are presented to fully inform readers. Note that many quantities shown in various tables have been subject to rounding; therefore, aggregation of basic and intermediate quantities may differ from the values shown.
Advanced Resources International
Development of Nuclear Magnetic Resonance Pulse Sequences and Probes to Study Biomacromolecules
The determination of the three dimensional structures at high resolution of biomolecules, such as proteins and nucleic acids, enables us to understand their function at the molecular level. At the present time, there are only two methods available for determining such structures, nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction. Compared to well-established X-ray diffraction techniques, NMR methodology is relatively new and has many areas in which improvement can still be attained. In this project, we focused on the development of new NMR probes and pulse sequences that were tailored to tackle specific problems that are not adequately addressed by current technology. Probes are the hardware that contain the radio frequency (RF) circuitry used to both excite and detect the NMR signals. Pulse sequences are composed of a series of RF pulses and delays, which are applied to the sample held within the magnetic field by the probe, so as to manipulate the nuclear spins. Typically, a probe is developed for a specific set of nuclei and types of experiments and the pulse sequences are then written to use the probe in an optimal manner. In addition, the inter-development of instrumentation and methods are determined by the specific biological question to be examined. Thus our efforts focused on addressing an area of importance in NMR Structural Biology namely more effective ways to use the phosphorus ({sup 31}P) nucleus. Phosphorus is a very important biological element that is strategically located in nucleic acids, where it imparts negative charge and flexibility to RNA and DNA. It is also a component of the cellular membrane and thus interacts with membrane proteins. It is used in mechanisms to signal, activate or deactivate enzymes; and participates in energy storage and release. However, the phosphorus nucleus exhibits certain properties, such as poor spectral dispersion, low sensitivity of detection, and fast relaxation, which limit its effective use in NMR studies of biomolecules. Our unique combination of expertise at LLNL allowed us to tackle each of the negative features of {sup 31}P-NMR in a three-pronged, concerted effort. The nature of our work necessitated an interdependent, multidisciplinary approach that required knowledge of spin physics (pulse sequences), engineering (probes), and structural biology (sample preparation and structure determination).
Cosman, M; Krishnan, V V; Maxwell, R
The true role of active communicators: an empirical study of Jazz core developers
Context: Interest in software engineering (SE) methodologies and tools has been complemented in recent years by research efforts oriented towards understanding the human processes involved in software development. This shift has been imperative ... Keywords: Jazz, behaviors, content analysis, core developers, psycholinguistics, roles, software development
Sherlock A. Licorish; Stephen G. MacDonell
A System Dynamics Approach for Developing Zone Water Demand Forecasting: A Case Study of Linkong Area
System dynamics (SD) approach for developing zone water demand forecasting was developed based on the analysis of its water resources system which has multi-feedback and nonlinear interactions amongst system elements. As an example, Tianjin Binhai Linkong ... Keywords: developing zone, system dynamics, water resources demand, Linkong
Xuehua Zhang; Hongwei Zhang; Xinhua Zhao
A Comparative Study of the Rates of Development of Potential Graupel and Hail Embryos in High Plains Storms
The rates of development of graupel and hail in High Plains storms are calculated based on mechanisms for the growth of particles of various types. In the first part of this study, planar crystals, aggregates, graupel particles and frozen drops ...
Andrew J. Heymsfield
Tale of two studies: challenges in field research with low-literacy adult learners in a developed country
Efforts to address the problems of literacy are often focused on developing countries. However, functional illiteracy is a challenge encountered by up to 50% of adults in developed countries. In this paper we reflect on the challenges we faced in trying ... Keywords: assistive technology, educational interfaces, evaluation methodology, interface design, mobile computing, mobile learning, user studies
Cosmin Munteanu; Heather Molyneaux; Julie Maitland; Daniel McDonald; Rock Leung; Joanna Lumsden; H�l�ne Fournier
Liquid phase methanol LaPorte process development unit: Modification, operation, and support studies
Liquid-entrained operations at the LaPorte Liquid Phase Methanol (LPMEOH) Process Development Unit (PDU) continued during June and July 1988 under Tasks 2.1 and 2.2 of Contract No. DE-AC22-87PC90005 for the US Department of Energy. The primary focus of this PDU operating program was to prepare for a confident move to the next scale of operation with an optimized and simplified process. Several new design options had been identified and thoroughly evaluated in a detailed process engineering study completed under the LPMEOH Part-2 contract (DE-AC22-85PC80007), which then became the basis for the current PDU modification/operating program. The focus of the Process Engineering Design was to optimize and simplifications focused on the slurry loop, which consists of the reactor, vapor/liquid separator, slurry heat exchanger, and slurry circulation pump. Two-Phase Gas Holdup tests began at LaPorte in June 1988 with nitrogen/oil and CO- rich gas/oil systems. The purpose of these tests was to study the hydrodynamics of the reactor, detect metal carbonyl catalyst poisons, and train operating personnel. Any effect of the new gas sparger and the internal heat exchanger would be revealed by comparing the hydrodynamic data with previous PDU hydrodynamic data. The Equipment Evaluation'' Run E-5 was conducted at the LaPorte LPMEOH PDU in July 1988. The objective of Run E-5 was to systematically evaluate each new piece of equipment (sparger, internal heat exchanger, V/L disengagement zone, demister, and cyclone) which had been added to the system, and attempt to run the reactor in an internal-only mode. In addition, a successful catalyst activation with a concentrated (45 wt % oxide) slurry was sought. 9 refs., 26 figs., 15 tabs.
Liquid Phase Methanol LaPorte Process Development Unit: Modification, operation, and support studies
A gas phase and a slurry phase radioactive tracer study was performed on the 12 ton/day Liquid Phase Methanol (LPMEOH) Process Development Unit (PDU) in LaPorte, Texas. To study the gas phase mixing characteristics, a radioactive argon tracer was injected into the feed gas and residence time distribution was generated by measuring the response at the reactor outlet. Radioactive manganese oxide powder was independently injected into the reactor to measure the slurry phase mixing characteristics. A tanks-in-series model and an axial dispersion model were applied to the data to characterize the mixing in the reactor. From the axial dispersion model, a translation to the number of CSTR's (continuous stirred tank reactors) was made for comparison purposes with the first analysis. Dispersion correlations currently available in the literature were also compared. The tanks-in-series analysis is a simpler model whose results are easily interpreted. However, it does have a few drawbacks; among them, the lack of a reliable method for scaleup of a reactor and no direct correlation between mixing in the slurry and gas phases. The dispersion model allows the mixing in the gas and slurry phases to be characterized separately while including the effects of phase transfer. This analysis offers a means for combining the gas and slurry phase dispersion models into an effective dispersion coefficient, which, in turn, can be related to an equivalent number of tanks-in-series. The dispersion methods reported are recommended for scaleup of a reactor system. 24 refs., 18 figs., 8 tabs.
Environmental studies conducted at the Fenton Hill Hot Dry Rock geothermal development site
An environmental investigation of Hot Dry Rock (HDR) geothermal development was conducted at Fenton Hill, New Mexico, during 1976-1979. Activities at the Fenton Hill Site included an evaluation of baseline data for biotic and abiotic ecosystem components. Identification of contaminants produced by HDR processes that had the potential for reaching the surrounding environment is also discussed. Three dominant vegetative communities were identified in the vicinity of the site. These included grass-forb, aspen, and mixed conifer communities. The grass-forb area was identified as having the highest number of species encountered, with Phleum pratense and Dactylis glomerata being the dominant grass species. Frequency of occurrence and mean coverage values are also given for other species in the three main vegetative complexes. Live trapping of small mammals was conducted to determine species composition, densities, population, and diversity estimates for this component of the ecosystem. The data indicate that Peromyscus maniculatus was the dominant species across all trapping sites during the study. Comparisons of relative density of small mammals among the various trapping sites show the grass-forb vegetative community to have had the highest overall density. Comparisons of small mammal diversity for the three main vegetative complexes indicate that the aspen habitat had the highest diversity and the grass-forb habitat had the lowest. Analyses of waste waters from the closed circulation loop indicate that several trace contaminants (e.g., arsenic, cadmium, fluoride, boron, and lithium) were present at concentrations greater than those reported for surface waters of the region.
Miera, F.R. Jr.; Langhorst, G.; McEllin, S.; Montoya, C.
Studies on the development of mossy zinc electrodeposits from flowing alkaline electrolytes
The initiation and characteristics of mossy zinc electrodeposits have been investigated. Batteries with zinc electrodes are candidates for electric vehicle applications; however, this electrode is prone to form non-compact deposits that contribute to capacity loss and battery failure. Moss is deposited when the current density is far from the limiting current. This morphology first appears only after the bulk deposit is approximately 1 {mu}m thick. In this investigation, the effects of flow rate (Re=0--4000), current density (0--50 mA/cm{sup 2}), concentration of the electroactive species (0.25 and 0.5 M), and the concentration of supporting electrolyte (3, 6, and 12 M) on the initiation of moss were examined. The rotating concentric cylinder electrode was employed for most of the experiments; and a flow channel was used to study the development of morphology. After the experiment, the deposit was characterized using microscopic, x-ray diffraction, and profilometric techniques. 94 refs., 72 figs.
Mc Vay, L.
Municipal solid waste management challenges in developing countries - Kenyan case study
This paper provides an overview of the state of municipal solid waste management (MSWM) by local authorities in Kenya as a case study of a low-income developing country. Approaches of possible solutions that can be undertaken to improve municipal solid waste (MSW) services are discussed. Poor economic growth (1.1% in 1993) has resulted in an increase in the poverty level which presently stands at 56%. Migration from the rural areas to the urban areas has resulted in unplanned settlements in suburban areas accommodating about 60% of the urban population on only 5% urban land area. Political interference also hampers smooth running of local authorities. Vulnerability of pollution of surface and groundwater is high because local authorities rarely considered environmental impact in siting MSW disposal sites. Illegal dumping of MSW on the river banks or on the roadside poses environmental and economic threats on nearby properties. Poor servicing of MSW collection vehicles, poor state of infrastructure and the lack of adequate funding militate against optimization of MSW disposal service. The rural economy needs to be improved if rural-urban migration is to be managed. Involvement of stakeholders is important to achieve any meaningful and sustainable MSWM. The role of the informal sector through community-based organizations (CBOs), Non-Governmental Organizations (NGOs) and the private sector in offering solutions towards improvement of MSWM also is explored.
Henry, Rotich K. [College of Environment and Resources, Jilin University, Changchun 130026 (China); Zhao Yongsheng [College of Environment and Resources, Jilin University, Changchun 130026 (China)]. E-mail: firstname.lastname@example.com; Dong Jun [College of Environment and Resources, Jilin University, Changchun 130026 (China)
Photovoltaics as a worldwide energy option: A case study in development strategy
Renewable energy technologies, such as solar thermal electric, photovoltaics (PV), and wind energy have made significant gains in cost and performance in the past decades. As a result, there have been high expectations on the part of the public for these sources to play a major role in future energy supply, especially as environmental concerns about conventional sources increase. Despite these past gains and high expectations, the global potential of renewable energy technologies still remains largely untapped, principally because of issues of industrialization and user acceptance. There is increasing recognition that government energy programs must incorporate a broader strategy than the traditional basic research role if they are to address these issues. Essential elements of this strategy are affordable technology, a healthy industry, sustained market growth, user acceptance, and equitable policy and financial environments. The US Department of Energy (DOE) programs in solar electric conversion have already started the development of the required broader-based effort. This paper presents the status of that work, utilizing the US National Photovoltaic Program as a case study.
Jones, G.; Pate, R.; Hill, R.
A Prospective Cohort Study on Radiation-induced Hypothyroidism: Development of an NTCP Model
Purpose: To establish a multivariate normal tissue complication probability (NTCP) model for radiation-induced hypothyroidism. Methods and Materials: The thyroid-stimulating hormone (TSH) level of 105 patients treated with (chemo-) radiation therapy for head-and-neck cancer was prospectively measured during a median follow-up of 2.5 years. Hypothyroidism was defined as elevated serum TSH with decreased or normal free thyroxin (T4). A multivariate logistic regression model with bootstrapping was used to determine the most important prognostic variables for radiation-induced hypothyroidism. Results: Thirty-five patients (33%) developed primary hypothyroidism within 2 years after radiation therapy. An NTCP model based on 2 variables, including the mean thyroid gland dose and the thyroid gland volume, was most predictive for radiation-induced hypothyroidism. NTCP values increased with higher mean thyroid gland dose (odds ratio [OR]: 1.064/Gy) and decreased with higher thyroid gland volume (OR: 0.826/cm{sup 3}). Model performance was good with an area under the curve (AUC) of 0.85. Conclusions: This is the first prospective study resulting in an NTCP model for radiation-induced hypothyroidism. The probability of hypothyroidism rises with increasing dose to the thyroid gland, whereas it reduces with increasing thyroid gland volume.
Boomsma, Marjolein J.; Bijl, Hendrik P.; Christianen, Miranda E.M.C.; Beetz, Ivo; Chouvalova, Olga; Steenbakkers, Roel J.H.M. [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Laan, Bernard F.A.M. van der [Department of Otorhinolaryngology/Head and Neck Surgery, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Wolffenbuttel, Bruce H.R. [Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Endocrinology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Oosting, Sjoukje F. [Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Schilstra, Cornelis [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)] [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands); Langendijk, Johannes A., E-mail: email@example.com [Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen (Netherlands)
Numerical Investigation of Thermal Hydraulic Behavior of Supercritical Carbon Dioxide in Compact Heat Exchangers
The present work seeks to investigate the thermal hydraulic (heat transfer and fluid dynamics) behavior of supercritical (Sc) fluids at both the fundamental and applied levels. The thermal hydraulics of these fluids is not very well known although they have been used in various applications. There are drastic changes in the thermal and hydraulic properties of fluids at supercritical conditions. There has been a lot of focus to effectively utilize these properties changes in many applications such as heat exchangers. This work focuses on studying the forced convective heat transfer of Sc-CO2 in a series of mini semi-circular horizontal tubes and a zig-zag shaped horizontal channel. The problems were investigated numerically by second-order finite volume method using a commercial software FLUENT. Three dimensional Computational Fluid Dynamics (CFD) models were developed to simulate the flow and heat transfer for three different geometries � a single semi-circular channel, a series of nine parallel semi-circular channels and a zig-zag channel. Grid and accuracy refinement studies were carried out to assess numerical errors. All the computational meshes developed for this study incorporated the first node cell within the viscous sub-layer i.e. y heat transfer solution for these problems. The present numerical work focuses on improving the CFD model and methodologies in order to capture the experimental data of the heat transfer spike at the super critical conditions. Local and average heat transfer coefficients near the critical point were determined from measured wall temperatures and calculated local bulk temperatures. The numerical results are compared with the experiments. The numerical predictions do not convincingly agree with the experiments. This could be because of the incapability of turbulent models to capture the flow physics accurately due to the rapid changes in the fluid properties near critical conditions.
Fatima, Roma
Mechanisms of Cell Regeneration, Development, and Propagation within a Two-Dimensional Multicell Storm
In this study, mechanisms of cell regeneration, development, and propagation within a two-dimensional multicell storm are investigated using a numerical cloud model. The cell regeneration is explained by the advection mechanism. The following ...
Yuh-Lang Lin; Roy L. Deal; Mark S. Kulie
Development of a fully-consistent reduced order model to study instabilities in boiling water reactors
A simple nonlinear Reduced Order Model to study global, regional and local instabilities in Boiling Water Reactors is described. The ROM consists of three submodels: neutron-kinetic, thermal-hydraulic and heat-transfer models. The neutron-kinetic model allows representing the time evolution of the three first neutron kinetic modes: the fundamental, the first and the second azimuthal modes. The thermal-hydraulic model describes four heated channels in order to correctly simulate out-of-phase behavior. The coupling between the different submodels is performed via both void and Doppler feedback mechanisms. After proper spatial homogenization, the governing equations are discretized in the time-domain. Several modifications, compared to other existing ROMs, have been implemented, and are reported in this paper. One novelty of the ROM is the inclusion of both azimuthal modes, which allows to study combined instabilities (in-phase and out-of-phase), as well as to investigate the corresponding interference effects between them. The second modification concerns the precise estimation of so-called reactivity coefficients or C{sub mn}{sup *V,D} - coefficients by using direct cross-section data from SIMULATE-3 combined with the CORE SIM core simulator in order to calculate Eigenmodes. Furthermore, a non-uniform two-step axial power profile is introduced to simulate the separate heat production in the single and two-phase regions, respectively. An iterative procedure was developed to calculate the solution to the coupled neutron-kinetic/thermal-hydraulic static problem prior to solving the time-dependent problem. Besides, the possibility of taking into account the effect of local instabilities is demonstrated in a simplified manner. The present ROM is applied to the investigation of an actual instability that occurred at the Swedish Forsmark-1 BWR in 1996/1997. The results generated by the ROM are compared with real power plant measurements performed during stability tests and show a good qualitative agreement. The present study provides some insight in a deeper understanding of the physical principles which drive both core-wide and local instabilities. (authors)
Dykin, V.; Demaziere, C. [Chalmers Univ. of Technology, Div. of Nuclear Engineering, Dept. of Applied Physics, SE-412 96 Gothenburg (Sweden)
Exploring the Outer Limits of Numerical Relativity
We perform several black-hole binary evolutions using fully nonlinear numerical relativity techniques at separations large enough that low-order post-Newtonian expansions are expected to be accurate. As a case study, we evolve an equal-mass nonspinning black-hole binary from a quasicircular orbit at an initial coordinate separation of D=100M for three different resolutions. We find that the orbital period of this binary (in the numerical coordinates) is T=6422M. The orbital motion agrees with post-Newtonian predictions to within 1%. Interestingly, we find that the time derivative of the coordinate separation is dominated by a purely gauge effect leading to an apparent contraction and expansion of the orbit at twice the orbital frequency. Based on these results, we improved our evolution techniques and studied a set of black hole binaries in quasi-circular orbits starting at D=20M, D=50M, and D=100M for ~ 5, 3, and 2 orbits, respectively. We find good agreement between the numerical results and post-Newtonian predictions for the orbital frequency and radial decay rate, radiated energy and angular momentum, and waveform amplitude and phases. The results are relevant for the future computation of long-term waveforms to assist in the detection and analysis of gravitational waves by the next generation of detectors as well as the long-term simulations of black-hole binaries required to accurately model astrophysically realistic circumbinary accretion disks.
Carlos O. Lousto; Yosef Zlochower
Wintertime Supercell Thunderstorms in a Subtropical Environment: Numerical Simulation
Following an earlier diagnostic study, the present paper performs numerical simulations of the rare wintertime supercell storms during 19�20 December 2002 in a subtropical environment near Taiwan. Using Japan Meteorology Agency (JMA) 20-km ...
Chung-Chieh Wang; George Tai-Jen Chen; Shan-Chien Yang; Kazuhisa Tsuboki
An Eddy Resolving Numerical Model of the Ventilated Thermocline
A three-dimensional, primitive equation numerical model is used to study the effects of mesoscale eddies within the subtropical thermocline. Solutions are obtained for an ocean bounded by idealized topography are driven by simple wind and ...
Michael D. Cox
Numerical Modeling of Gravity Wave Generation by Deep Tropical Convection
Although convective clouds are known to generate internal gravity waves, the mechanisms responsible are not well understood. The present study seeks to clarify the dynamics of wave generation using a high-resolution numerical model of deep ...
Todd P. Lane; Michael J. Reeder; Terry L. Clark
Numerical Simulations of Shelterbelt Effects on Wind Direction
A neutral boundary layer nonhydrostatic numerical model is used to determine the characteristics of shelterbelt effects on mean wind direction and to study the processing causing wind rotation when air passes through a shelterbelt. The model uses ...
Hao Wang; Eugene S. Takle
TEM Study on the Phase Development and Microstructure in a U-7 ...
Abstract Scope, Fuel development for the Reduced Enrichment for Research .... Characterization of the Delta Phase Formation in Uranium-Zirconium Alloy Fuels.
Recent developments in atomic/nuclear methodologies used for the study of cultural heritage objects
Archaeometry is an area established in the international community since the 60s, with extensive use of atomic-nuclear methods in the characterization of art, archaeological and cultural heritage objects in general. In Brazil, however, until the early '90s, employing methods of physics, only the area of archaeological dating was implemented. It was only after this period that Brazilian groups became involved in the characterization of archaeological and art objects with these methodologies. The Laboratory of Applied Nuclear Physics, State University of Londrina (LFNA/UEL) introduced, pioneered in 1994, Archaeometry and related issues among its priority lines of research, after a member of LFNA has been involved in 1992 with the possibilities of tomography in archaeometry, as well as the analysis of ancient bronzes by EDXRF. Since then, LFNA has been working with PXRF and Portable Raman in several museums in Brazil, in field studies of cave paintings and in the laboratory with material sent by archaeologists, as well as carrying out collaborative work with new groups that followed in this area. From 2003/2004 LAMFI/DFN/IFUSP and LIN/COPPE/UFRJ began to engage in the area, respectively with methodologies using ion beams and PXRF, then over time incorporating other techniques, followed later by other groups. Due to the growing number of laboratories and institutions/archaeologists/conservators interested in these applications, in may 2012 was created a network of available laboratories, based at http://www.dfn.if.usp.br/lapac. It will be presented a panel of recent developments and applications of these methodologies by national groups, as well as a sampling of what has been done by leading groups abroad.
Appoloni, Carlos Roberto [Departamento de Fisica, CCE, Universidade Estadual de Londrina - UEL, P.O.Box 6001, CEP 86055-990, Londrina, PR (Brazil)
Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository - BMT1 of the DECOVALEX III project. Part 3: Effects of THM coupling in sparsely fractured rocks
de Cadarache (CEA), and Japan Nuclear Fuel Cycle DevelopmentS�ret� Nucl�aire; the Japan Nuclear Fuel Cycle DevelopmentSafety Commission JNC Japan Nuclear Fuel Cycle Development
The dynamic simulation of organic farming development scenarios - A case study in Slovenia
In this paper a system dynamics model for organic farming development to support government decision making is presented. The system incorporates relevant variables which affect organic farming development. The user seeks answers to strategic questions ... Keywords: Model, Organic farming, Simulation, System dynamics
Rtomir Rozman, Karmen Paek, Miroljub Kljaji?, Martina Bavec, Jernej Turk, Franc Bavec, Davorin Kofja?, Andrej �Kraba
Thermal numerical simulator for laboratory evaluation of steamflood oil recovery
A thermal numerical simulator running on an IBM AT compatible personal computer is described. The simulator was designed to assist laboratory design and evaluation of steamflood oil recovery. An overview of the historical evolution of numerical thermal simulation, NIPER's approach to solving these problems with a desk top computer, the derivation of equations and a description of approaches used to solve these equations, and verification of the simulator using published data sets and sensitivity analysis are presented. The developed model is a three-phase, two-dimensional multicomponent simulator capable of being run in one or two dimensions. Mass transfer among the phases and components is dictated by pressure- and temperature-dependent vapor-liquid equilibria. Gravity and capillary pressure phenomena were included. Energy is transferred by conduction, convection, vaporization and condensation. The model employs a block centered grid system with a five-point discretization scheme. Both areal and vertical cross-sectional simulations are possible. A sequential solution technique is employed to solve the finite difference equations. The study clearly indicated the importance of heat loss, injected steam quality, and injection rate to the process. Dependence of overall recovery on oil volatility and viscosity is emphasized. The process is very sensitive to relative permeability values. Time-step sensitivity runs indicted that the current version is time-step sensitive and exhibits conditional stability. 75 refs., 19 figs., 19 tabs.
Sarathi, P.
Numerical Analysis Gordon K. Smyth
to the fundamental ideas of numerical analysis is given by Stewart [11]. This article discusses the basic ideas be represented on a computer. Therein lies the fundamental difference between exact and com puter arithmetic, I. A. (1962). Handbook of mathematical functions. National Bureau of Stan dards, Washington
Smyth, Gordon K.
]. An elegant and elementary introduction to the fundamental ideas of numerical analysis is given by Stewart [11 be represented on a computer. Therein lies the fundamental difference between exact and computer arithmetic] Abramowitz, M. & Stegun, I.A. (1962). Handbook of Mathematical Functions. National Bureau of Standards
Numerical Simulations of Black Holes
Numerical Simulations of Black Holes 26 Aug 2009 Frank Herrmann (email@example.com) Department · merger of compact objects Much more than just black hole evolutions · Formulations · Hyperboloidal)/2.0; . . . high arithmetic intensity Operator Number of times used 12,961 + 5,398 - 3,438 / 69 14 #12;Black Hole
Maryland at College Park, University of
Public service impacts of geothermal development: cumulative impacts study of the Geysers KGRA. Final staff report
The number of workers currently involved in the various aspects of geothermal development in the Geysers are identified. Using two different development scenarios, projections are made for the number of power plants needed to reach the electrical generation capacity of the steam resource in the Geysers. The report also projects the cumulative number of workers needed to develop the steam field and to construct, operate, and maintain these power plants. Although the number of construction workers fluctuates, most are not likely to become new, permanent residents of the KGRA counties. The administrative and public service costs of geothermal development to local jurisdications are examined, and these costs are compared to geothermal revenues accruing to the local governments. Revenues do not cover the immediate fiscal needs resulting from increases in local road maintenance and school enrollment attributable to geothermal development. Several mitigation options are discussed and a framework presented for calculating mitigation costs for school and road impacts.
Matthews, K.M.
Cumulative impacts study of The Geysers KGRA: public-service impacts of geothermal development
Geothermal development in The Geysers KGRA has affected local public services and fiscal resources in Sonoma, Lake, Mendocino, and Napa counties. Each of these counties underwent rapid population growth between 1970 and 1980, some of which can be attributed to geothermal development. The number of workers currently involved in the various aspects of geothermal development in The Geysers is identified. Using three different development scenarios, projections are made for the number of power plants needed to reach the electrical generation capacity of the steam resource in The Geysers. The report also projects the cumulative number of workers needed to develop the steam field and to construct, operate, and maintain these power plants. Although the number of construction workers fluctuates, most are not likely to become new, permanent residents of the KGRA counties. The administrative and public service costs of geothermal development to local jurisdictions are examined and compared to geothermal revenues accruing to the local governments. Revenues do not cover the immediate fiscal needs resulting from increases in local road maintenance and school enrollment attributable to geothermal development. Several mitigation options are discussed, and a framework is presented for calculating mitigation costs per unit of public service.
Modelling energy-economy interactions in small developing countries : a case study of Sri Lanka
This report is addressed at modelling energy-economy interactions in small developing countries, those with populations less than 20 million or so and where neither the industrial or energy sectors are dominant. The overall ...
Blitzer, Charles R.
Advanced LWR Nuclear Fuel Cladding System Development Trade-Off Study
The Advanced Light Water Reactor (LWR) Nuclear Fuel Development Research and Development (R&D) Pathway encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. To achieve significant operating improvements while remaining within safety boundaries, significant steps beyond incremental improvements in the current generation of nuclear fuel are required. Fundamental improvements are required in the areas of nuclear fuel composition, cladding integrity, and the fuel/cladding interaction to allow power uprates and increased fuel burn-up allowance while potentially improving safety margin through the adoption of an �accident tolerant� fuel system that would offer improved coping time under accident scenarios. With a development time of about 20 � 25 years, advanced fuel designs must be started today and proven in current reactors if future reactor designs are to be able to use them with confidence.
Kristine Barrett; Shannon Bragg-Sitton
KM capability for software development: a case study of the Indian software firms
Organisational knowledge management (KM) capability is developed to allow companies to share, create and disseminate their organisational knowledge resources. The paradigm shift from traditional business to information communication technology (ICT) ...
Abdullah Kammani; Sultan Aljahdali; Hema Date
A Multiscale Observational Case Study of the Development of an Isolated High Plains Tornadic Supercell
On 21 May 1995, a strong tornado developed with an isolated supercell in southwestern Nebraska. Large-scale conditions were not supportive of a tornadic thunderstorm outbreak; however, evidence suggests significant mesoscale enhancements produced ...
Mace L. Bentley; Michael Buban; Stonie Cooper
Multiwavelength Observations of a Developing Cloud System: The FIRE II 26 November 1991 Case Study
Simultaneous multiwavelength measurements of a developing cloud system were obtained by NOAA Doppler lidar, Doppler radar, Fourier transform infrared interferometer, and microwave and infrared radiometers on 26 November 1991. The evolution of the ...
J. M. Intrieri; W. L. Eberhard; T. Uttal; J. A. Shaw; J. B. Snider; Y. Han; B. W. Orr; S. Y. Matrosov
Tenements : dwellings for the urban poor. Comparative study illustrating 28 cases in developing countries
Tenements are significant systems that provide habitation to the poor in most of the urban areas of the developing countries. Yet, tenements are practically ignored if not prohibited by the public sector and consequently ...
Aliman, Isam Mohammad
The Development of an Airborne Infrared Interferometer for Meteorological Sounding Studies
The United Kingdom Meteorological Office (UKMO) has developed an airborne interferometer to act as a simulator for future satellite-based infrared meteorological sounders. The Airborne Research Interferometer Evaluation System (ARIES) consists of ...
S. H. S. Wilson; N. C. Atkinson; J. A. Smith
The process of resort second home development demand quantification : exploration of methodologies and case study application
Prevalent methodologies utilized by resort second home development professionals to quantify demand for future projects are identified and critiqued. The strengths of each model are synthesized in order to formulate an ...
Wholey, Christopher J. (Christoper John)
Studies in ion source development for application in heavy ion fusion
Ion Sources for Heavy Ion Fusion Applications . Ph.D.Sources for Heavy Ion Fusion . Proceedings of the ParticleDevelopment for Heavy Ion Fusion. Wollnik, H. , Optics of
Kapica, Jonathan G.
Numerical length estimation for tubular flow reactors
Keywords: free boundary value problems, noniterative and iterative numerical methods, tubular flow reactors
Riccardo Fazio
Evaluating electronic banking systems in developing nations through Analytic Hierarchy Process model: a case study
Since the beginning of the late 1970s an impressive number of innovative electronic banking systems have been developed and tested commercially. One of the most important issues with respect to these innovations is the choosing best electronic banking ... Keywords: AHP, ATM banking, Iran, analytical hierarchy process, bank remark factors, developing countries, e-banking, electronic banking, internet banking, m-banking SMS banking, mobile banking, online banking, phone banking, security factors, socioeconomic factors, technological factors, telephone banking
Ehsan Rasolinezhad
Sludge Treatment and Extraction Technology Development: Results of FY 1993 studies
This report describes experimental results from work conducted in FY 1993 under the Sludge Treatment and Extraction Technology Development Task of the Tank Waste Remediation System (TWRS) Pretreatment Technology Development Project at Pacific Northwest Laboratory (PNL). Experiments were conducted in the following six general areas: (1) sludge washing, (2) sludge leaching, (3) sludge dissolution, (4) actinide separation by solvent extraction and extraction chromatography, (5) Sr separation by solvent extraction, and (6) extraction of Cs from acidic solution.
Lumetta, G.J.; Wagner, M.J.; Barrington, R.J.; Rapko, B.M.; Carlson, C.D.
Confronting Models with Data: The GEWEX Cloud Systems Study
The Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) was organized to promote the development of improved parameterizations of cloud systems for use in climate and numerical weather prediction models, with an emphasis on ...
David Randall; Steven Krueger; Christopher Bretherton; Judith Curry; Peter Duynkerke; Mitchell Moncrieff; Brian Ryan; David Starr; Martin Miller; William Rossow; George Tselioudis; Bruce Wielicki
Symposium on Fuels from Biomass. DOE meeting, Troy, New ~orkSTUDIES FOR CONVERSION OF BIOMASS TO SUGARS AND ETHANOL C.STUDIES FOR CONVERSION OF BIOMASS TO SUGARS AND ETHANOL* by
Wilke, C.R.
Essays using military-induced variation to study social interactions, human capital development, and labor markets
This dissertation consists of four empirical studies, each using military-induced variation to examine various aspects of human capital production and the U.S. labor market. The first two chapters study the effects of ...
Lyle, David S. (David Stephen), 1971-
Development and Testing of a Frozen Soil Parameterization for Cold Region Studies
Proper simulation of soil freezing and thawing processes is an important issue in cold region climate studies. This paper reports on a frozen soil parameterization scheme for cold region studies that includes water flow and heat transfer in soil ...
Xia Zhang; Shu Fen Sun; Yongkang Xue
Vegetation component of geothermal EIS studies: Introduced plants, ecosystem stability, and geothermal development
This paper contributes new information about the impacts from introduced plant invasions on the native Hawaiian vegetation as consequences of land disturbance and geothermal development activities. In this regard, most geothermal development is expected to act as another recurring source of physical disturbance which favors the spread and maintenance of introduced organisms throughout the region. Where geothermal exploration and development activities extend beyond existing agricultural and residential development, they will become the initial or sole source of disturbance to the naturalized vegetation of the area. Kilauea has a unique ecosystem adapted to the dynamics of a volcanically active landscape. The characteristics of this ecosystem need to be realized in order to understand the major threats to the ecosystem and to evaluate the effects of and mitigation for geothermal development in Puna. The native Puna vegetation is well adapted to disturbances associated with volcanic eruption, but it is ill-adapted to compete with alien plant species in secondary disturbances produced by human activities. Introduced plant and animal species have become a major threat to the continued presence of the native biota in the Puna region of reference.
Low-rank coal study: national needs for resource development. Volume 3. Technology evaluation
Technologies applicable to the development and use of low-rank coals are analyzed in order to identify specific needs for research, development, and demonstration (RD and D). Major sections of the report address the following technologies: extraction; transportation; preparation, handling and storage; conventional combustion and environmental control technology; gasification; liquefaction; and pyrolysis. Each of these sections contains an introduction and summary of the key issues with regard to subbituminous coal and lignite; description of all relevant technology, both existing and under development; a description of related environmental control technology; an evaluation of the effects of low-rank coal properties on the technology; and summaries of current commercial status of the technology and/or current RD and D projects relevant to low-rank coals.
Study on development of education model and its evaluation system for radiation safety
As one of the detailed action strategy of multi object preparedness for strengthening of radiation safety management by MOST, this project was performed, in order to promote the safety culture for user and radiation worker through effective education program. For the prevention of radiological accident and effective implementation of radiation safety education and training, this project has been carried out the development of education model and its evaluation system on radiation safety. In the development of new education model, education course was classified; new and old radiation worker, temporary worker, lecturer and manager. The education model includes the contents of expanding the education opportunity and workplace training. In the development of evaluation system, the recognition criteria for commission-education institute and inside-education institute which should establish by law were suggested for evaluation program. The recognition criteria contains classification, student, method, facilities, ...
Seo, K W; Nam, Y M
Numerical Schemes for Rough Parabolic Equations
This paper is devoted to the study of numerical approximation schemes for a class of parabolic equations on (0,1) perturbed by a non-linear rough signal. It is the continuation of Deya (Electron. J. Probab. 16:1489-1518, 2011) and Deya et al. (Probab. Theory Relat. Fields, to appear), where the existence and uniqueness of a solution has been established. The approach combines rough paths methods with standard considerations on discretizing stochastic PDEs. The results apply to a geometric 2-rough path, which covers the case of the multidimensional fractional Brownian motion with Hurst index H>1/3.
Deya, Aurelien, E-mail: firstname.lastname@example.com [Universite de Nancy 1, Institut Elie Cartan Nancy (France)
Software engineering education: A study on conducting collaborative senior project development
Project and teamwork training is recognized as an important aspect in software engineering (SE) education. Senior projects, which often feature industrial involvement, serve the function of a 'capstone course' in SE curricula, by offering comprehensive ... Keywords: Collaborative development, Meetings-flow, Senior project, Software engineering education
Chung-Yang Chen; P. Pete Chong
A Case Study of Nonmesocyclone Tornado Development in Northeast Colorado: Similarities to Waterspout Formation
The evolution of the 26 July 1985 Erie, Colorado tornado is described using data from NCAR's CP-2 Doppler radar. This tornado develops within 20 km of the radar site under weakly forced synoptic conditions and weak tropospheric flow, and is not ...
Raymond H. Brady; Edward J. Szoke
Feasibility Study on Wind Farm Renewable Energy Development in the Eastern Coast of China
Eastern China has a vast land area with a long coastline, presenting a possible wind resource. But the use of the wind renewable energy to generate electric power is still on a small scale, because of the large upfront investment and lower internal rate ... Keywords: Wind renewable energy, clean development mechanism, greenhouse gas emission reductions
Huang Xiangning; Ma Xiuqin; Wang Jing
Framework for energy policy and technology assessment in developing countries: a case study of Peru
The potential of various energy sources and technology options in meeting national economic and social development goals in developing countries is assessed. The resource options that are of interest are the development of indigenous resources. In general, two categories of options can be considered: those which correspond to the accelerated implementation of existing elements of the energy system and those which correspond to the introduction of a new technology, such as solar electricity. The various resource and technology options that must be analyzed with respect to a number of criteria or payoff functions are: total demand and fuel mix; reduction of oil consumption; national social goals; total energy costs; and environmental quality. First, a view is constructed of the energy implications of current national economic development plans. A consistent description of the future energy system of the country, under the assumption of current trends and policies is constructed for certain reference years in the future. The values of the payoff functions selected are then calculated for that reference case. The major resource and technology options are identified and the rates at which they can be implemented are determined. Finally, the impact on the various payoff functions of the implementation of each option is calculated. The basic element of the framework is the Reference Energy System, discussed in Secton 3. The energy policy analysis for Peru is used as a reference case. 11 references, 10 figures, 2 tables.
Mubayi, V.; Palmedo, P.F.; Doernberg, A.B.
Influence of confirmation biases of developers on software quality: an empirical study
The thought processes of people have a significant impact on software quality, as software is designed, developed and tested by people. Cognitive biases, which are defined as patterned deviations of human thought from the laws of logic and mathematics, ... Keywords: Confirmation bias, Defect prediction, Human factors, Software psychology
G�l �al?kl?; Ay?e Ba?ar Bener
Analyzing the oil refining industry in developing countries: A comparative study of China and India
The oil refining industry is a critical link in the energy chain in many developing and industrialized countries, transforming crude oil into transport fuels (gasoline, jet fuel, and diesel), residual fuel oil (widely used as a fuel in industry and the electric power sector), and other products such as kerosine, frequently for lighting an cooking usages. Three to four decades ago, the demand for oil products in most developing countries was centered to a few large cities; thus, few refineries were built in these regions. But because of the astonishing economic growth in many developing nations, demand for oil products has increased rapidly. As a result, the refining industry has expanded rapidly in such countries, even in cases were there is no domestic crude oil production. Oil product demand and refinery expansion in Asian developing countries in particular have experienced significant growth. Between 1976 and 1993, oil product demand and refinery capacity in that region (excluding Japan) increased annually an average of 5.2 percent and 4.3 percent, respectively, whereas the comparable figures for the world as a whole remained virtually unchanged during the same period. The substantial gains in Asia`s crude oil production in the 1970s is believed to have facilitated this refinery expansion.
Tang, F.C.
Numerical modeling and experimental testing of a solar grill
The sun provides a free, nonpolluting and everlasting source of energy. Considerable research has been carried out to utilize solar energy for purposes such as water heating, high temperature ovens, and conversion to electrical energy. One of the interesting forms for utilizing solar energy is cooking. The main disadvantage of solar energy systems has been the low efficiency attained in most of its practical applications. It is expected, however, that due to continuing decreases in the availability of other energy sources such as oil and coal, along with the safety problems associated with nuclear energy, man's need for utilization of solar energy will increase, thus leading him to find the ways and means to develop adequate and efficient solar-powered systems. In camps, where tents are used to accommodate people, cooking is done via conventional gas stoves. This usually takes place in extremely crowded areas which become highly fireprone. Solar oven cookers seem to be a viable alternative considering both economy and safety. Among the various forms of solar cookers, the oven-type solar cooker is known to be the best in terms of efficiency. One of the most practical and efficient forms of solar oven cookers is the outdoor portable solar grill (Bar-B-Q), developed by Khalifa et al. The solar grill is a light and portable unit that utilizes solar energy to grill meat. One of the best types of grilling with this cooker is the well-known Shish Kebab or Bar-B-Q. A detailed description for the design of the solar grill is provided as follows. This paper is aimed at providing experimental results and formulating a numerical model for the solar grill. Results of the two approaches are then compared to verify the validity of the numerical simulation. An experimental and theoretical investigation was conducted on the solar grill in order to study the factors that affect its design and performance.
Olwi, I.; Khalifa, A. (King Abdulaziz Univ., Jeddah (Saudi Arabia))
Numerical study of the thm effects on the near-field safety of a hypothetical nuclear waste repository - bmt1 of the decovalex iii project. part 1: conceptualization and characterization of the problems and summary of results
071, Power Reactor and Nuclear Fuel Development Corporation,safety assessment of a nuclear fuel waste repository in aPower Reactor and Nuclear Fuel Development Corporation.
Numerical codes for MHD flows. Quarterly technical progress report
The objective of this work is to develop numerical techniques and codes for characterizing coal-combustion-operated MHD generators and diffusers. The purpose for this activity is twofold: (a) provide the MHD Division of the Department of Energy with evaluative guidelines in selecting and exercising channel codes; (b) provide users with codes to design MHD channel/diffusers and evaluate their performance. The scope of work calls for four tasks: 1) unsteady one-dimensional channel code: to modify an existing time-dependent code to include MHD effects for approximate predictions of the flow from the combustion chamber through the diffuser; 2) multidimensional channel codes: to develop codes for predicting the complete inviscid-viscous flow across the duct in an MHD generator and diffuser; 3) slag layer studies and heat transfer analyses: to adapt an existing code to predict the stability conditions of slag layers which are driven by turbulent exterior flows and to develop a code for predicting slag layer growth; and 4) arc formation, migration, and electrode erosion: to conduct transient analyses in evaluating the inter-electrode arcing and constricted discharges from th gas to the electrode in the presence of Hall current. A summary of the current progress on these tasks is presented.
Blottner, F.G.; Russo, A.J.; Taylor, J.G.; Hadley, G.R.
A Potential Enstrophy and Energy Conserving Numerical Scheme for Solution of the Shallow-Water Equations on a Geodesic Grid
Using the shallow water equations, a numerical framework on a spherical geodesic grid that conserves domain-integrated mass, potential vorticity, potential enstrophy, and total energy is developed. The numerical scheme is equally applicable to ...
Todd D. Ringler; David A. Randall
DOE-STD-1058-93: Guide to Good Practices for Developing and Conducting Case Studies; Replaced by DOE-HDBK-1116-98
Energy.gov (U.S. Department of Energy (DOE))
This guide contains a method for learning fromexperience to prevent mistakes fromoccurring. That method is the case study. This guide describes how to develop and present case studies.
Numerical simulation of transient, incongruent vaporization induced by high power laser
A mathematical model and numerical calculations were developed to solve the heat and mass transfer problems specifically for uranum oxide subject to laser irradiation. It can easily be modified for other heat sources or/and other materials. In the uranium-oxygen system, oxygen is the preferentially vaporizing component, and as a result of the finite mobility of oxygen in the solid, an oxygen deficiency is set up near the surface. Because of the bivariant behavior of uranium oxide, the heat transfer problem and the oxygen diffusion problem are coupled and a numerical method of simultaneously solving the two boundary value problems is studied. The temperature dependence of the thermal properties and oxygen diffusivity, as well as the highly ablative effect on the surface, leads to considerable non-linearities in both the governing differential equations and the boundary conditions. Based on the earlier work done in this laboratory by Olstad and Olander on Iron and on Zirconium hydride, the generality of the problem is expanded and the efficiency of the numerical scheme is improved. The finite difference method, along with some advanced numerical techniques, is found to be an efficient way to solve this problem.
Tsai, C.H.
An exploratory study of forces and frictions affecting large-scale model-driven development
In this paper, we investigate model-driven engineering, reporting on an exploratory case-study conducted at a large automotive company. The study consisted of interviews with 20 engineers and managers working in different roles. We found that, in the ...
Adrian Kuhn; Gail C. Murphy; C. Albert Thompson
FINESSE: study of the issues, experiments and facilities for fusion nuclear technology research and development. Interim report. Volume I
The following chapters are included in this study: (1) fusion nuclear issues, (2) survey of experimental needs, (3) requirements of the experiments, (4) non-fusion facilities, (5) fusion facilities for nuclear experiments, and (6) fusion research and development scenarios. (MOW)
Abdou, M.
Design and development of a test facility to study two-phase steam/water flow in porous media
The approach taken at Lawrence Berkeley Laboratory to obtain relative permeability curves and their dependence on fluid and matrix properties is summarized. Thermodynamic studies are carried out to develop the equations governing two-phase steam/water flow in porous media and to analyze the relationship between mass flow rate and flowing enthalpy. These relationships will be verified against experimental results and subsequently will be used to develop a field analysis technique to obtain in-situ relative permeability parameters. Currently our effort is concentrated on thermodynamic analysis and development of an experimental facility. Some of the findings of the theoretical work are presented and also the design and development effort for the experimental facility is described.
Verma, A.K.; Pruess, K.; Bodvarsson, G.S.; Tsang, C.F.; Witherspoon, P.A.
Development of static and simulation programs for voltage stability studies of bulk power system
In the analysis and evaluation of voltage stability, it is necessary to accurately identify the stability margin at each load point under specific system configuration or power balance condition. Voltage stability margin can be basically identified by the multi-solution load flow calculation method. When predicted by this static analysis that voltage instability may occur, time domain simulation will be required which includes the models of various control equipments related with system voltage profile. To deal with this, the following two analytical computer codes shown below were developed. (1) Voltage stability static analysis computer code employing a new load flow calculation method. (2) Time domain long term simulation computer code for voltage stability. These computer codes can also calculate the voltage stability index at each load point which is based on the margin to the stability power limit at each load point. The practicality of these codes developed were verified by applying to the IEEE-118 test system.
Nagao, T.; Tanaka, K.; Takenaka, K. [Central Research Inst. of Electric Power Industry, Tokyo (Japan)
Models and Inputs Developed for Use in the xLPR Pilot Study
The eXtremely Low Probability of Rupture (xLPR) Project is a multi-year, cooperative effort between the U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research and the Electric Power Research Institute (EPRI) Materials Reliability Program (MRP) to develop a fully probabilistic computational tool capable of evaluating degradation in reactor coolant piping leading to rupture with extremely low probabilities of occurrence. Due to the complexity of this undertaking, a limited scope pil...
Cycle Life Studies of Advanced Technology Development Program Gen 1 Lithium Ion Batteries
This report presents the test results of a special calendar-life test conducted on 18650-size, prototype, lithium-ion battery cells developed to establish a baseline chemistry and performance for the Advanced Technology Development Program. As part of electrical performance testing, a new calendar-life test protocol was used. The test consisted of a once-per-day discharge and charge pulse designed to have minimal impact on the cell yet establish the performance of the cell over a period of time such that the calendar life of the cell could be determined. The calendar life test matrix included two states of charge (i.e., 60 and 80%) and four temperatures (40, 50, 60, and 70�C). Discharge and regen resistances were calculated from the test data. Results indicate that both discharge and regen resistance increased nonlinearly as a function of the test time. The magnitude of the discharge and regen resistance depended on the temperature and state of charge at which the test was conducted. The calculated discharge and regen resistances were then used to develop empirical models that may be useful to predict the calendar life or the cells.
Wright, Randy Ben; Motloch, Chester George
Calendar Life Studies of Advanced Technology Development Program Gen 1 Lithium Ion Batteries
A Diagnostic Case Study of Self-Development as an Antecedent Conditioning Process in Explosive Cyclogenesis
A diagnostic study of two, successive operational model forecasts of a case of explosive cyclogenesis is presented, with the goal of understanding the rather substantial differences in the simulations. The rapid cyclogenesis, Which occurred to ...
Paul J. Roebber
Numerical Simulation and Analysis of a Prefrontal Squall Line. Part II: Propagation of the Squall Line as an Internal Gravity Wave
A numerical study of the squall line that occurred on 17�18 June 1978 was described in Part I of this paper. The squall line was collocated with a surface front during its initial development (at 0000 UTC 18 June 1978), but then propagated faster ...
Jennifer M. Cram; Roger A. Pielke; William R. Cotton
A Summertime Antarctic Mesocyclone Event over the Southern Pacific during FROST SOP-3: A Mesoscale Analysis Using AVHRR, SSM/I, ERS, and Numerical Model Data
The development of three summertime mesoscale cyclones (MCs) over the northern Amundsen and Bellingshausen Seas from 10 to 12 January 1995 (during FROST SOP-3) is studied by means of AVHRR data, ERS and SSM/I retrievals, and mesoscale numerical ...
Michael Lieder; G�nther Heinemann
Getting a kick out of numerical relativity
Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. Our estimated kick is 105 km/s with an error of less than 10%. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts z > 10, halos with masses < 10^9 M_sun w...
Baker, J G; Choi, D I; Koppitz, M; Miller, M C; Van Meter, J R; Baker, John G.; Centrella, Joan; Choi, Dae-Il; Koppitz, Michael; Meter, James R. van
Recent developments in numerical relativity have made it possible to follow reliably the coalescence of two black holes from near the innermost stable circular orbit to final ringdown. This opens up a wide variety of exciting astrophysical applications of these simulations. Chief among these is the net kick received when two unequal mass or spinning black holes merge. The magnitude of this kick has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters. Here we report the first accurate numerical calculation of this kick, for two nonspinning black holes in a 1.5:1 mass ratio, which is expected based on analytic considerations to give a significant fraction of the maximum possible recoil. We have performed multiple runs with different initial separations, orbital angular momenta, resolutions, extraction radii, and gauges. The full range of our kick speeds is 86--116 km s$^{-1}$, and the most reliable runs give kicks between 86 and 97 km s$^{-1}$. This is intermediate between the estimates from two recent post-Newtonian analyses and suggests that at redshifts $z\\gtrsim 10$, halos with masses $\\lesssim 10^9 M_\\odot$ will have difficulty retaining coalesced black holes after major mergers.
John G. Baker; Joan Centrella; Dae-Il Choi; Michael Koppitz; James R. van Meter; M. Coleman Miller
Handbook of numerical heat transfer
A comprehensive presentation is given of virtually all numerical methods that are suitable for the analysis of the various heat transverse and fluid flow problems that occur in research, practice, and university instruction. After reviewing basic methodologies, the following topics are covered: finite difference and finite element methods for parabolic, elliptic, and hyperbolic systems; a comparative appraisal of finite difference versus finite element methods; integral and integrodifferential systems; perturbation methods; Monte Carlo methods; finite analytic methods; moving boundary problems; inverse problems; graphical display methods; grid generation methods; and programing methods for supercomputers.
Minkowycz, W.J.; Sparrow, E.M.; Schneider, G.E.; Pletcher, R.H.
Leveraging Limited Data Resources: Developing Commercial End-Use Information: B.