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A 3-D hydrodynamic dispersion model for modeling tracer transport in Geothermal Reservoirs

Description: A 3-D hydrodynamic dispersion model for tracer transport is developed and implemented into the TOUGH2 EOS3 (T2R3D) module. The model formulation incorporates a full dispersion tensor, based on a 3-D velocity field with a 3-D, irregular grid in a heterogeneous geological system. Two different weighting schemes are proposed for spatial average of 3-D velocity fields and concentration gradients to evaluate the mass flux by dispersion and diffusion of a tracer or a radionuclide. This new module of the TOUGH2 code is designed to simulate processes of tracer/radionuclide transport using an irregular, 3-D integral finite difference grid in non-isothermal, three-dimensional, multiphase, porous/fractured subsurface systems. The numerical method for this transport module is based on the integral finite difference scheme, as in the TOUGH2 code. The major assumptions of the tracer transport module are: (a) a tracer or a radionuclide is present and transported only within the liquid phase, (b) transport mechanisms include molecular diffusion and hydrodynamic dispersion in the liquid phase in addition to advection, and (c) first order decay and linear adsorption on rock grains are taken into account. The tracer or radionuclide is introduced as an additional mass component into the standard TOUGH2 formulation, time is discretized fully implicitly, and non-linearities of the conservation equations are handled using the Newton/Raphson iteration. We have verified this transport module by comparison with results of a 2-D transport problem for which an analytical solution is available. In addition, a field application is described to demonstrate the use of the proposed model.
Date: January 26, 1998
Creator: Wu, Yu-Shu & Pruess, Karsten
Partner: UNT Libraries Government Documents Department

Advanced Light Source Compendium of User Abstracts andTechnical Reports 1997

Description: The Advanced Light Source (ALS), a national user facility located at Ernest Orlando Lawrence Berkeley National Laboratory of the University of California is available to researchers from academia, industry, and government laboratories. Operation of the ALS is funded by the Department of Energy's Office of Basic Energy Sciences. This Compendium contains abstracts written by users summarizing research completed or in progress during 1997, ALS technical reports describing ongoing efforts related to improvement in machine operations and research and development projects, and information on ALS beamlines planned through 1998.
Date: July 1, 1998
Creator: Cross, J.; Devereaux, M.K.; Dixon, D.J.; Greiner, A. & editors
Partner: UNT Libraries Government Documents Department

Amorphous Diamond Flat Panel Displays - Final Report of ER-LTR CRADA project with SI Diamond Technology

Description: The objective of this project was to determine why diamond-based films are unusually efficient electron emitters (field emission cathodes) at room temperature. Efficient cathodes based on diamond are being developed by SI Diamond Technology (SIDT) as components for bright, sunlight-readable, flat panel displays. When the project started, it was known that only a small fraction (<1%) of the cathode area is active in electron emission and that the emission sites themselves are sub-micron in size. The critical challenge of this project was to develop new microcharacterization methods capable of examining known emission sites. The research team used a combination of cathode emission imaging (developed at SIDT), micro-Raman spectroscopy (LBNL), and electron microscopy and spectroscopy (National Center for Electron Microscopy, LBNL) to examine the properties of known emission sites. The most significant accomplishment of the project was the development at LBNL of a very high resolution scanning probe that, for the first time, measured simultaneously the topography and electrical characteristics of single emission sites. The increased understanding of the emission mechanism helped SIDT to develop a new cathode material,''nano-diamond,'' which they have incorporated into their Field Emission Picture Element (FEPix) product. SIDT is developing large-format flat panel displays based on these picture elements that will be brighter and more efficient than existing outdoor displays such as Jumbotrons. The energy saving that will be realized if field emission displays are introduced commercially is in line with the energy conservation mission of DOE. The unique characterization tools developed in this project (particularly the new scanning microscopy method) are being used in ongoing BES-funded basic research.
Date: May 8, 1998
Creator: Ager III, Joel W.
Partner: UNT Libraries Government Documents Department

W Boson physics at the Fermilab Tevatron Collider

Description: Recent results from the CDF and D0 Experiments at the Fermilab Tevatron Collider are presented for the W and Z boson production cross sections, the W boson width, rare W boson decays, trilinear gauge boson couplings, and the W boson mass.
Date: August 1, 1998
Creator: Madaras, Ronald J.
Partner: UNT Libraries Government Documents Department

Technology and Greenhouse Gas Emissions: An IntegratedScenario Analysis

Description: This report describes an analysis of possible technology-based scenarios for the U.S. energy system that would result in both carbon savings and net economic benefits. We use a modified version of the Energy Information Administration's National Energy Modeling System (LBNL-NEMS) to assess the potential energy, carbon, and bill savings from a portfolio of carbon saving options. This analysis is based on technology resource potentials estimated in previous bottom-up studies, but it uses the integrated LBNL-NEMS framework to assess interactions and synergies among these options. The analysis in this paper builds on previous estimates of possible "technology paths" to investigate four major components of an aggressive greenhouse gas reduction strategy: (1) the large scale implementation of demand-side efficiency, comparable in scale to that presented in two recent policy studies on this topic; (2) a variety of "alternative" electricity supply-side options, including biomass cofiring, extension of the renewable production tax credit for wind, increased industrial cogeneration, and hydropower refurbishment. (3) the economic retirement of older and less efficient existing fossil-find power plants; and (4) a permit charge of $23 per metric ton of carbon (1996 $/t),l assuming that carbon trading is implemented in the US, and that the carbon permit charge equilibrates at this level. This level of carbon permit charge, as discussed later in the report, is in the likely range for the Clinton Administration's position on this topic.
Date: September 1, 1998
Creator: Koomey, J.G.; Latiner, S.; Markel, R.J.; Marnay, C. & Richey, R.C.
Partner: UNT Libraries Government Documents Department

Technology Assessment Report: Duty Cycling Controllers Revisited

Description: This report covers an assessment of two brands of energy management controllers that are currently being offered that utilize the principle of duty cycling to purportedly save energy for unitary air conditioners and heat pumps, gas furnaces, and gas fired boilers. The results of an extensive review of past research on this subject as well as a review of vendor sponsored field testing of these controllers compares these newer controllers to those of the past. Included also is a discussion of how the duty cycling principle is prone to misinterpretation as to its potential to save energy.
Date: May 1, 1998
Creator: Webster, Tom & Benenson, Peter
Partner: UNT Libraries Government Documents Department

Cosmological moduli problem in a supersymmetric model with direct gauge mediation

Description: Recently, an interesting class of the direct gauge mediation supersymmetry (SUSY) breaking models are proposed, in which the minimum of the potential of the SUSY breaking field is determined by the inverted hierarchy mechanism. We consider their cosmological implications. In this class of models, SUSY breaking field has a very flat potential, which may have a cosmological importance. Assuming the initial amplitude of the SUSY breaking field to be of the order of the Planck scale, it can be a source of a large entropy production. A special attention is paid to the cosmological moduli problem, and we will see the cosmological mass density of the moduli field can be significantly reduced.
Date: July 7, 1998
Creator: Moroi, Takeo
Partner: UNT Libraries Government Documents Department

Self-dual nonsupersymmetric Type II String Compactifications

Description: It has recently been proposed that certain nonsupersymmetric type II orbifolds have vanishing perturbative contributions to the cosmological constant. We show that techniques of Sen and Vafa allow one to construct dual type II descriptions of these models (some of which have no weakly coupled heterotic dual). The dual type II models are given by the same orbifolds with the string coupling S and a T{sup 2} volume T exchanged. This allows us to argue that in various strongly coupled limits of the original type II models, there are weakly coupled duals which exhibit the same perturbative cancellations as the original models.
Date: August 17, 1998
Creator: Kachru, Shamit & Silverstein, Eva
Partner: UNT Libraries Government Documents Department

Self-pinched beam transport experiments Relevant to Heavy Ion Driven inertial fusion energy

Description: An attractive feature of the inertial fusion energy (IFE) approach to commercial energy production is that the fusion driver is well separated from the fusion confinement chamber. This ''standoff'' feature means the driver is largely isolated from fusion reaction products. Further, inertial confinement fusion (ICF) target ignition (with modest gain) is now scheduled to be demonstrated at the National Ignition Facility (NIF) using a laser driver system. The NIF program will, to a considerable extent, validate indirectly-driven heavy-ion fusion (HIF) target designs for IFE. However, it remains that HIF standoff between the final focus system and the fusion target needs to be seriously addressed. In fact, there now exists a timely opportunity for the Office of Fusion Energy Science (OFES) to experimentally explore the feasibility of one of the attractive final transport options in the fusion chamber: the self-pinched transport mode. Presently, there are several mainline approaches for HIF beam transport and neutralization in the fusion chamber. These range from the (conservative) vacuum ballistic focus, for which there is much experience from high energy research accelerators, to highly neutralized ballistic focus, which matches well to lower voltage acceleration with resulting lower driver costs. Alternatively, Z-discharge channel transport and self-pinched transport in gas-filled chambers may relax requirements on beam quality and final focusing systems, leading to even lower driver cost. In any case, these alternative methods of transport, especially self-pinched transport, are unusually attractive from the standpoint of chamber design and neutronics. There is no requirement for low chamber pressure. Moreover, only a minuscule fraction of the fusion neutrons can escape from the chamber. Therefore, it is relatively easy to shield sensitive components, e-g., superconducting magnets from any significant neutron flux. Indeed, self-pinched transport and liquid wall protection endow DT fusion with many of the advantages of aneutronic fusion. The question ...
Date: February 6, 1998
Creator: Herrmannsfeldt, W.B.; Bangerter, R.O.; Fessenden, T.J.; Lee, E.P.; Yu, S.S.; Olson, C.L. et al.
Partner: UNT Libraries Government Documents Department

Several TOUGH2 Modules Developed for Site Characterization Studies of Yucca Mountain

Description: A comprehensive site characterization study has been conducted for the unsaturated zone (UZ) of Yucca Mountain to investigate its suitability as a potential high-level nuclear waste repository. Numerical modeling of moisture, gas, chemicals and heat flow, and their influence on the repository performance has been proven to be essential in understanding unsaturated-zone fluid movement, and the effects of hydrogeologic, geochemical and thermal conditions on various aspects of the overall waste disposal system. In these studies, the TOUGH2 code has been used extensively as a main modeling tool because of its flexibility and robustness in handling multiphase, multi-component fluid and heat flow and chemical transport in porous/fractured rocks. As part of the UZ modeling efforts at LBNL, several new modules of the TOUGH2 code have been developed to meet different needs of the site characterization studies. In this paper they will summarize some of these new TOUGH2 modules and their specific features in application to the Yucca Mountain project. These new TOUGH2 modules include (1) the effective continuum model (ECM) for treating fracture/matrix flow; (2) single-phase gas flow (EOS1G) in a water-air two phase flow system; and (3) a 3-D radionuclide transport module (T2R3D) for 3-D radionuclide or tracer transport in porous/fractured media under two-phase flow and non-isothermal conditions.
Date: January 2, 1998
Creator: Wu, Yu-Shu & Pruess, Karsten
Partner: UNT Libraries Government Documents Department

Simulated Impact of Roof Solar Absorptance, Attic, and DuctInsulation, and Climate on Cooling and Heating Energy Use inSingle-Family Resi dential Buildings

Description: This report summarizes a comparative analysis of the impact of roof surface solar absorptance, attic, and duct insulation on simulated residential annual cooling and heating energy use in sixteen sunbelt climates. These locations cover a wide range of climates where cool roofs are expected to save energy and money, and are areas with high growth rates in new residential construction. The residences are single-story, single-family of new construction with either a gas furnace or an electric heat pump, and with ducts in the attic OT conditioned zone. The objective is to demonstrate that a residence with a cool roof could utilize a lower level of attic insulation than one with a dark roof with a zero net change in the annual energy bill. Annual energy use is simulated with DOE-2. lE, which was adapted with a validated residential duct-attic function, for dark and cool roofs and eleven attic insulation R-values ranging from 1 through 60. Analysis of the simulated energy savings from the light-colored roofs show that the savings can be transformed into an equivalent reduction in the level of attic insulation. Reductions in R-value are observed in varying degrees for residences with both gas and electric heat, all duct configurations, and all climates. In some cooling dominated climates there are cases where a cool roof could be implemented without attic insulation.
Date: October 26, 1998
Creator: Akbari, H. & Konopacki, S.
Partner: UNT Libraries Government Documents Department

Vaporizing Flow in Hot Fractures: Observations from Laboratory Experiments

Description: Understanding water seepage in hot fractured rock is important in a number of fields including geothermal energy recovery and nuclear waste disposal. Heat-generating high-level nuclear waste packages which will be emplaced in the partially saturated fractured tuffs at the potential high-level nuclear waste repository at Yucca Mountain, Nevada, if it becomes a high-level nuclear waste repository, will cause significant impacts on moisture distribution and migration. Liquid water, which occupies anywhere from 30 to 100% of the porespace, will be vaporized as the temperature reaches the boiling temperature. Flowing primarily in fractures, the vapor will condense where it encounters cooler rock, generating mobile water. This water will flow under gravitational and capillary forces and may flow back to the vicinity of the emplaced waste where it may partially escape vaporization. Water flowing down (sub-) vertical fractures may migrate considerable distances through fractured rock that is at above-boiling temperatures; thus, flowing condensate may contact waste packages, and provide a pathway for the transport of water-soluble radionuclides downward to the saturated zone. Thermally-driven flow processes induced by repository heat may be as important or even more important for repository performance than natural infiltration. For a nominal thermal loading of 57 kW/acre, vaporization may generate an average equivalent percolation flux from condensate of 23.1 mm/yr over 1,000 years, and 5.2 mm/yr over 10,000 years. These numbers are comparable to or larger than current estimates of net infiltration at Yucca Mountain. This condensate, which is generated in the immediate vicinity (meters) of the waste packages, will likely have a larger impact on waste package and repository performance than a similar amount of water introduced at the land surface.
Date: December 1, 1998
Creator: Kneafsey, T. & Pruess, K.
Partner: UNT Libraries Government Documents Department

Characteristics of Microseismicity in the DV11 Injection Area, Southeast Geysers, California

Description: Microearthquake (MEQ) occurrence surrounding the injection well DV11 in Unit 18 of the Southeast (SE) Geysers is investigated. Seismicity rates are compared to the injection rate, and to flow rates in nearby steam extraction wells, which were monitored during the Unit 18 Cooperative Injection Test in 1994 and 1995. The seismicity rate is seen to mirror both injection and production rates, although a time lag sometimes occurs. Waveform cross-correlation is performed for the MEQs in the DV11 area, and the events grouped into clusters based on waveform similarity. Relative location techniques applied to the events in two of these clusters show 7 events grouped into a volume of about 25 m in diameter, at an elevation of about -0.65 km msl and 5 events grouped into a vertically-oriented linear feature about 100 m in length, at about -1.8 km msl.
Date: November 1, 1998
Creator: Kirkpatrick, Ann; Peterson Jr., John E.; Majer, Ernest L. & Nadeau, Robe rt
Partner: UNT Libraries Government Documents Department

Survey Talk--New Laser and Optical RadiationDiagnostics

Description: New techniques am reported for electron beam monitoring, that rely either on the analysis of the properties of wiggler radiation (from static magnetic fields as well as from laser "undulators", also referred to as Thomson scattering) or on the non-linear mixing of laser radiation with electron beam radiation. The different techniques reviewed are capable of providing information on femtosecond time scales and micron or even sub-micron spatial scales. The laser undulator is also proposed as a useful tool for non- destructive measurement of high power electron beams. An example is given of measuring electron beam energy and energy spread through spectral filtering of spontaneous wiggler radiation [1]. A novel technique based on fluctuational characteristics of radiation is described, for single shot, nondestructive measurement of the electron beam bunch length [2,3]. Thomson scattering based beam monitoring techniques are discussed which, through analysis of the radiated beam properties, allow non-destructive detailed measurement of transverse and longitudinal distributions of relativistic electron beams [4]. Two new techniques are discussed which rely on non-linear optical mixing of laser radiation with electron bunch emission: differential optical gating (DOG) [5] and electron bunch length measurement in a storage ring based on sum-frequency generation [6].
Date: September 1, 1998
Creator: Leemans, W.P.
Partner: UNT Libraries Government Documents Department

Estimates of Hadronic Backgrounds in Future e+e- LinearColliders

Description: We have estimated hadronic backgrounds for an e+e- linear collider at a center- of-mass energy of 5 TeV. In order to achieve a required luminosity in TeV e+ e- colliders, the high beamstrahlung parameter {Upsilon}, such as several thousands, is caused. In the high {Upsilon} regime, the {gamma}{gamma} luminosities due to the collision of beamstrahlung photons are calculated by using the CAIN code. According to the {gamma}{gamma} luminosity distribution, we have estimated the hadronic backgrounds of {gamma}{gamma} {yields} minijets based on the parton distributions of the Drees and Grassie model by the PYTHIA 5.7 code. The Japan Linear Collider (J LC-1) detector simulator is applied for selection performances in the detector.
Date: May 1, 1998
Creator: Ohgaki, Tomomi
Partner: UNT Libraries Government Documents Department

Monitoring and Data Analysis for the Vadose Zone Monitoring System (VZMS), McClellan AFB. Quarterly Status Report (2/20/98 - 5/20/98)

Description: This report contains information on field and laboratory work performed between February 20th, 1998 and May 20th, 1998, at site S-7 in IC 34, at McClellan AFB. At this location, a Vadose Zone Monitoring System (VZMS) (LBNL, 1996) is currently being used to collect subsurface data including hydraulic potential, soil gas pressure, moisture content, water chemistry, gas chemistry, and temperature. This report describes: moisture content changes, based on neutron logging; gas-phase VOC concentrations; aqueous-phase VOC concentrations; temperature profiles; and installation of new instrument cluster.
Date: June 18, 1998
Creator: Zawislanski, P.T.; Mountford, H.S.Monitoring and Data Analysis; System, for the Vadose Zone Monitoring; Mountford, H.S.; Dahlquist, R. & Rodriguez, S.J.
Partner: UNT Libraries Government Documents Department