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A Domain Decomposition Approach for Large-Scale Simulations of Flow Processes in Hydrate-Bearing Geologic Media

Description: Simulation of the system behavior of hydrate-bearing geologic media involves solving fully coupled mass- and heat-balance equations. In this study, we develop a domain decomposition approach for large-scale gas hydrate simulations with coarse-granularity parallel computation. This approach partitions a simulation domain into small subdomains. The full model domain, consisting of discrete subdomains, is still simulated simultaneously by using multiple processes/processors. Each processor is dedicated to following tasks of the partitioned subdomain: updating thermophysical properties, assembling mass- and energy-balance equations, solving linear equation systems, and performing various other local computations. The linearized equation systems are solved in parallel with a parallel linear solver, using an efficient interprocess communication scheme. This new domain decomposition approach has been implemented into the TOUGH+HYDRATE code and has demonstrated excellent speedup and good scalability. In this paper, we will demonstrate applications for the new approach in simulating field-scale models for gas production from gas-hydrate deposits.
Date: July 1, 2008
Creator: Zhang, Keni; Moridis, G.J.; Wu, Y.-S. & Pruess, K.
Partner: UNT Libraries Government Documents Department

Geospatial and Contextual Approaches to Energy Balance and Health

Description: This article examines associations between geographic and contextual features of the environment and elements of human energy balance, with a particular focus on research and opportunities in the United States.
Date: September 13, 2014
Creator: Berrigan, David; Hipp, J. Aaron; Hurvitz, Philip M.; James, Peter; Jankowska, Marta M.; Kerr, Jacqueline et al.
Partner: UNT College of Arts and Sciences

Temperature Gradient in Hall Thrusters

Description: Plasma potentials and electron temperatures were deduced from emissive and cold floating probe measurements in a 2 kW Hall thruster, operated in the discharge voltage range of 200-400 V. An almost linear dependence of the electron temperature on the plasma potential was observed in the acceleration region of the thruster both inside and outside the thruster. This result calls into question whether secondary electron emission from the ceramic channel walls plays a significant role in electron energy balance. The proportionality factor between the axial electron temperature gradient and the electric field is significantly smaller than might be expected by models employing Ohmic heating of electrons.
Date: November 24, 2003
Creator: Staack, D.; Raitses, Y. & Fisch, N.J.
Partner: UNT Libraries Government Documents Department

Transport calculations for D-T burning Tokamak reactors

Description: From topical meeting on technology of controlled nuclear fusion; San Diego, California, USA (16 Apr 1974). One-dimensional particle and energy balance equations are solved for a 50-50 D-- T burning Tokamak operating in the reactor regime. Steady-state solutions which satisfy MHD equilibrium and stability criteria are obtained for banana, plateau, and classical transport coefficients by suitable enhancement of the coefficients. The effects of trapped particle instabilities and impurities are investigated. (auth)
Date: January 1, 1973
Creator: Stacey, W.M. Jr.
Partner: UNT Libraries Government Documents Department

Using the ABLE facility to observe urbanization effects on planetary boundary layer processes

Description: The Argonne Boundary Layer Experiments (ABLE) facility, located in south central Kansas, east of Wichita, is devoted primarily to investigations of and within the planetary boundary layer (PBL), including the dynamics of the mixed layer during both day and night; effects of varying land use and landform; the interactive role of precipitation, runoff, and soil moisture; storm development; and energy budgets on scales of 10 to 100 km. With an expected lifetime of 10--15 years, the facility is well situated to observe the effects of gradual urbanization on PBL dynamics and structure as the Wichita urban area expands to the east and several small municipalities located within the study area expand. Combining the continuous measurements of ABLE with (1) ancillary continuous measurements of, for example, the Atmospheric Radiation Measurement (ARM) program and the Global Energy Water Cycle Experiment (GEWEX) programs and with (2) shorter, more intensive studies within ABLE, such as the Cooperative Atmosphere Surface Exchange Studies (CASES) Program, allows hypothesized features of urbanization, including heat island effects, precipitation enhancement, and modification of the surface energy budget partitioning, to be studied.
Date: December 31, 1998
Creator: Coulter, R.L.; Klazura, J.; Lesht, B.M.; Shannon, J.D.; Sisterson, D.L. & Wesely, M.L.
Partner: UNT Libraries Government Documents Department

Experimental Study of Ion Heating and Acceleration During Magnetic Reconnection

Description: Ion heating and acceleration has been studied in the well-characterized reconnection layer of the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)]. Ion temperature in the layer rises substantially during null-helicity reconnection in which reconnecting field lines are anti-parallel. The plasma out flow is sub-Alfvonic due to a downstream back pressure. An ion energy balance calculation based on the data and including classical viscous heating indicates that the ions are heated largely due to non-classical mechanisms. The Ti rise is much smaller during co-helicity reconnection in which field lines reconnect obliquely. This is consistent with a slower reconnection rate and a smaller resistivity enhancement over the Spitzer value. These observations indicate strongly that non-classical dissipation mechanisms can play an important role both in heating the ions and in facilitating the reconnection process.
Date: October 24, 2000
Creator: Hsu, S.C.; Carter, T.A.; Fiksel, G.; Ji, H.; Kulsrud, R.M. & Yamada, M.
Partner: UNT Libraries Government Documents Department

Field monitoring of solar domestic hot water systems based on simple tank temperature measurement

Description: By dynamically measuring solar storage tank temperature(s), the solar storage tank effectively becomes a dynamic calorimeter to measure the energy flows in a solar system. The energy flows include solar loop gain, tank losses, and potentially draw extraction. With one-channel temperature loggers storing data over several days to several weeks, this approach provides low-cost, modest-accuracy performance assessment, useful for determination of savings persistence and diagnostics. Analysis is based upon the tank energy balance, identifying solar gain during the day and tank losses at night. These gains and losses can be compared to expectations based upon prior knowledge, and estimated weather conditions. Diagnostics include controller and pump operation, and excessive nighttime losses. With one point temperature logger, solar gain accuracy is expected to be 20 to 50%, depending on draw frequency and volume. Two examples are shown, a properly operating system and a system with excessive nighttime losses.
Date: May 1, 1995
Creator: Burch, J.; Xie, Yuantao & Murley, C.S.
Partner: UNT Libraries Government Documents Department

Evidence of systematic biases in ocean surface heat fluxes simulated by AGCMs

Description: The Atmospheric Model Intercomparison Project has provided a unique opportunity to evaluate atmospheric general circulation model (AGCM) simulations made with realistic boundary forcing. Here we report on some results from AMIP Subproject No. 5, making use of a suite of observationally-based estimates of ocean surface heat fluxes to evaluate the seasonal cycle of surface heating as simulated by AGCMs.
Date: January 1, 1995
Creator: Gleckler, P.J. & Randall, D.A.
Partner: UNT Libraries Government Documents Department

Special properties of optical parametric oscillators

Description: Optical parametric oscillators (OPOS) are useful devices to generate tunable radiation. The tuning characteristics of OPOs can lead to their utility in remote sensing applications. We have investigated injection-seeded OPOs to generate narrow-band Mid-JR radiation for this purpose. OPOs exhibit a resonance structure similar to that of a laser`s cavity limiting the frequency choices available. Also, the coupling of the electric fields of the three interacting waves can generate cavity resonances for OPOs which have no cold cavity resonances (i.e. non-resonant OPOS). The potential for generating multiple frequencies simultaneously from a single OPO is discussed. The generation of multiple output frequencies is accomplished by injecting either multiple signal or multiple pump frequencies to the OPO. A seeded SRO is found to be well-suited to generating spectrally pure and stable multi-line output when the input pump field is multiple frequency. The generation of sideband frequencies during multiple seeding is also observed experimentally and addressed theoretically. The spectral purity of the OPO output is related to the frequency separation of the multi-line input as compared to the OPO cavity resonance structure.
Date: February 27, 1996
Creator: Neuman, W.A. & Velski, S.P.
Partner: UNT Libraries Government Documents Department

UNSAT-H Version 3.0:Unsaturated Soil Water and Heat Flow Model Theory, User Manual, and Examples

Description: The UNSAT-H model was developed at Pacific Northwest National Laboratory (PNNL) to assess the water dynamics of arid sites and, in particular, estimate recharge fluxes for scenarios pertinent to waste disposal facilities. To achieve the above goals for assessing water dynamics and estimating recharge rates, the UNSAT-H addresses soil water infiltration, redistribution, evaporation, plant transpiration, deep drainage, and soil heat flow. The UNSAT-H model simulates liquid water flow using the Richards equation, water vapor diffusion using Fick's law, and sensible heat flow using the Fourier equation. This report documents UNSAT-H Version 3.0. The report includes the bases for the conceptual model and its numerical implementation, benchmark test cases, example simulations involving layered soils and plants, and the code manual. Version 3.0 is an enhanced-capability update of UNSAT-H Version 2.0 (Fayer Jones 1990). New features include hysteresis, an iterative solution of head and temperature, an energy balance check, the modified Picard solution technique, additional hydraulic functions, multiple year simulation capability, and general enhancements. This report includes eight example problems. The first four are verification tests of UNSAT-H capabilities. The second four example problems are demonstrations of real-world situations.
Date: June 15, 2000
Creator: Fayer, Michael J
Partner: UNT Libraries Government Documents Department

KIVA-3V, Release 2: Improvements to KIVA-3V

Description: This report describes the changes made in the KIVA-3V computer program since its initial release version dated 24 March 1997. A variety of new features enhance the robustness, efficiency, and usefulness of the overall program for engine modeling. Among these are an automatic restart of the cycle with a reduced timestep in case of iteration limit or temperature overflow, which should greatly reduce the likelihood of having the code crash in mid run. A new option is the automatic deactivation of a port region when it is closed off from the engine cylinder and its reactivation when it again communicates with the cylinder. A number of corrections throughout the code improve accuracy, one of which also corrects the 2-D planar option to make it properly independent of the third dimension. Extensions to the particle-based liquid wall film model make the model somewhat more complete, although it is still considered a work-in-progress. In response to current research in fuel-injected engines, a split-injection option has been added. A new subroutine monitors the whereabouts of the liquid and gaseous phases of the fuel, and for combustion runs the energy balance data and emissions are monitored and printed. New features in the grid generator K3PREP and the graphics post-processor K3POST are also discussed.
Date: May 1, 1999
Creator: Amsden, Anthony A.
Partner: UNT Libraries Government Documents Department

Mississippi Climate & Hydrology Conference

Description: The GEWEX Continental International Project (GCIP), which started in 1995 and completed in 2001, held its grand finale conference in New Orleans, LA in May 2002. Participants at this conference along with the scientists funded through the GCIP program are invited to contribute a paper to a special issue of Journal of Geophysical Research (JGR). This special JGR issue (called GCIP3) will serve as the final report on scientific research conducted by GCIP investigators. Papers are solicited on the following topical areas, but are not limited to, (1) water energy budget studies; (2) warm season precipitation; (3) predictability and prediction system; (4) coupled land-atmosphere models; (5) climate and water resources applications. The research areas cover observations, modeling, process studies and water resources applications.
Date: May 1, 2002
Creator: Lawford, R. & Huang, J.
Partner: UNT Libraries Government Documents Department

Documentation of the Thermal Energy Balance Equation used in the USNT Model of the NUFT Flow and Transport Code

Description: The main purpose of this document is to describe the thermal energy balance used in the USNT module of the NUFT code (Nitao, 1998) and its derivation. We also address several specific issues that have arisen within the Yucca Mountain Project.
Date: June 28, 2000
Creator: Nitao, J.J.
Partner: UNT Libraries Government Documents Department

Residual Life and Strength Predictions and Life-Enhancement of Structures

Description: In this paper, a method to quantitatively evaluate the T{sub {var_epsilon}}* integral directly from the measured near-tip displacement field for laboratory specimens made of metallic materials, is presented. This is the first time that such an attempt became a success. In order to develop the procedure, we carefully examine the nature of T{sub {var_epsilon}}* Hence, the nature of T{sub {var_epsilon}}* is further revealed. Following Okada and Atluri (1997), the relationship between energy balance statements for a cracked plate and the T{sub {var_epsilon}}* is discussed. It is concluded that T{sub {var_epsilon}}* quantifies the deformation energy dissipated near crack tip region [an elongating strip of height e] per unit crack extension. In the evaluation of T{sub {var_epsilon}}* integral directly from measured displacement field, the use of deformation theory plasticity (J2-D theory) and the truncation of the near crack integral path on the experimental studies of Omori et el. (1995) are presented, and these show a good agreement with the results of finite element analysis.
Date: September 1, 1998
Creator: Okada, H. & Atluri, S.N.
Partner: UNT Libraries Government Documents Department

The Argonne boundary layer experiments facility : using minisodars to complement a wind profiler network.

Description: The Argonne Boundary Layer Experiments (ABLE) facility, located in south central Kansas, east of Wichita, is devoted primarily to investigations of and within the planetary boundary layer (PBL), including the dynamics of the mixed layer during both day and night; effects of varying land use and land form; the interactive role of precipitation, runoff, and soil moisture; storm development; and energy budgets on scales of 10 to 100 km. Located entirely within the Walnut River watershed, ABLE provides intense measurements within the northeast quadrant (Fig. 1) of the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) of the Atmospheric Radiation Measurement (ARM) Program (Stokes and Schwarz, 1994). By combining the continuous measurements of ABLE with ancillary continuous measurements of, for example, the ARM and the Global Energy Water cycle Experiment (GEWEX) (Kinster and Shukla, 1990) programs, ABLE provides a platform within which shorter, more intensive studies, such as those conducted by the Cooperative Atmosphere-Surface Exchange Studies (CASES) Program, can realize the full benefit of a wide variety of atmospheric measurements on many scales; this allows the study of hypothesized features of PBL development and dynamics, including frontal dynamics, nocturnal boundary development and breakdown, urban heat island effects, precipitation enhancement, and modification of the surface energy budget partitioning.
Date: June 5, 1998
Creator: Coulter, R. L.
Partner: UNT Libraries Government Documents Department

Surface Energy Balance System (SEBS) Handbook

Description: A Surface Energy Balance System (SEBS) has been installed collocated with each deployed ECOR system at the Southern Great Plains (SGP), North Slope of Alaska (NSA), Tropical Western Pacific (TWP), ARM Mobile Facility 1 (AMF1), and ARM Mobile Facility 2 (AMF2). The surface energy balance system consists of upwelling and downwelling solar and infrared radiometers within one net radiometer, a wetness sensor, and soil measurements. The SEBS measurements allow the comparison of ECOR sensible and latent heat fluxes with the energy balance determined from the SEBS and provide information on wetting of the sensors for data quality purposes.
Date: February 14, 2011
Creator: Cook, DR
Partner: UNT Libraries Government Documents Department

Sensitivity Analysis of Coupled Groundwater Processes within a Land Surface Model

Description: Management of surface water quality is often complicated by interactions between surface water and groundwater. Traditional Land-Surface Models (LSM) used for numerical weather prediction, climate projection, and as inputs to water management decision support systems, do not treat the lower boundary in a fully process-based fashion. LSMs have evolved from a leaky bucket to more sophisticated land surface water and energy budgets that typically have a so-called basement term to depict the bottom model layer exchange with deeper aquifers. Nevertheless, the LSM lower boundary is often assumed zero flux or the soil moisture content is set to a constant value; an approach that while mass conservative, ignores processes that can alter surface fluxes, runoff, and water quantity and quality. Conversely, models for saturated and unsaturated water flow, while addressing important features such as subsurface heterogeneity and three-dimensional flow, often have overly simplified upper boundary conditions that ignore soil heating, runoff, snow and root-zone uptake. In the present study, a state-of-the-art LSM (CLM2.0) and a variably-saturated groundwater model (ParFlow) have been coupled as single model, in single-column and distributed form. An initial set of single column simulations based on data from the Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) and synthetic data demonstrate the temporal dynamics of both of the coupled models. A 15-year single-column simulation using the data from the Usadievskiy catchment in Valdai, Russia demonstrate the coupled model's ability to accurately predict the soil moisture profile and location of the water table, in addition to water and energy balance within the watershed. The distributed coupled model will also be demonstrated using a series of spatially variable subsurface parameter runs, which will be used to investigate upscaling in land-surface models. The coupled model will ultimately be used to assist in the development of Total Maximum Daily Loads (TMDLs- a ...
Date: May 5, 2004
Creator: Maxwell, R M; Miller, N L & Kollet, S J
Partner: UNT Libraries Government Documents Department

Best Estimate Radiation Flux Value-Added Procedure: Algorithm Operational Details and Explanations

Description: This document describes some specifics of the algorithm for best estimate evaluation of radiation fluxes at Southern Great Plains (SGP) Central Facility (CF). It uses the data available from the three co-located surface radiometer platforms at the SGP CF to automatically determine the best estimate of the irradiance measurements available. The Best Estimate Flux (BEFlux) value-added procedure (VAP) was previously named Best Estimate ShortWave (BESW) VAP, which included all of the broadband and spectral shortwave (SW) measurements for the SGP CF. In BESW, multiple measurements of the same quantities were handled simply by designating one as the primary measurement and using all others to merely fill in any gaps. Thus, this “BESW” is better termed “most continuous,” since no additional quality assessment was applied. We modified the algorithm in BESW to use the average of the closest two measurements as the best estimate when possible, if these measurements pass all quality assessment criteria. Furthermore, we included longwave (LW) fields in the best estimate evaluation to include all major components of the surface radiative energy budget, and renamed the VAP to Best Estimate Flux (BEFLUX1LONG).
Date: October 1, 2002
Creator: Shi, Y. & Long, C. N.
Partner: UNT Libraries Government Documents Department

Energy Balance Bowen Ratio Station (EBBR) Handbook

Description: The energy balance Bowen ratio (EBBR) system produces 30-minute estimates of the vertical fluxes of sensible and latent heat at the local surface. Flux estimates are calculated from observations of net radiation, soil surface heat flux, and the vertical gradients of temperature and relative humidity (RH). Meteorological data collected by the EBBR are used to calculate bulk aerodynamic fluxes, which are used in the Bulk Aerodynamic Technique (BA) EBBR value-added product (VAP) to replace sunrise and sunset spikes in the flux data. A unique aspect of the system is the automatic exchange mechanism (AEM), which helps to reduce errors from instrument offset drift.
Date: February 23, 2011
Creator: Cook, DR
Partner: UNT Libraries Government Documents Department

Cloud Occurrence Frequency at the Barrow, Alaska, ARM Climate Research Facility for 2008 Third Quarter 2009 ARM and Climate Change Prediction Program Metric Report

Description: Clouds represent a critical component of the Earth’s atmospheric energy balance as a result of their interactions with solar and terrestrial radiation and a redistribution of heat through convective processes and latent heating. Despite their importance, clouds and the processes that control their development, evolution and lifecycle remain poorly understood. Consequently, the simulation of clouds and their associated feedbacks is a primary source of inter-model differences in equilibrium climate sensitivity. An important step in improving the representation of cloud process simulations is an improved high-resolution observational data set of the cloud systems including their time evolution. The first order quantity needed to understand the important role of clouds is the height of cloud occurrence and how it changes as a function of time. To this end, the Atmospheric Radiation Measurement (ARM) Climate Research Facilities (ACRF) suite of instrumentation has been developed to make the observations required to improve the representation of cloud systems in atmospheric models.
Date: July 14, 2009
Creator: Jensen, M; Johnson, K & Mather, JH
Partner: UNT Libraries Government Documents Department