236 Matching Results

Search Results

Advanced search parameters have been applied.

Aperture studies for the AP2 anti-proton Line at Fermilab

Description: The AP2 beamline transports anti-protons from the production target to the Debuncher ring. For many years the observed aperture has been smaller than that estimated from linear, on-energy optics. We have investigated possible reasons for the aperture restriction and have identified several possible sources, including residual vertical dispersion from alignment errors and chromatic effects due to very large chromatic lattice functions. We discuss the possible sources, suggest some remedies, and propose specific studies, where needed, to evaluate suspected problems.
Date: December 5, 2003
Creator: Reichel, Ina; Zisman, Michael & Placidi, Massimo
Partner: UNT Libraries Government Documents Department

Estimation of field-scale soil hydraulic and dielectric parametersthrough joint inversion of GPR and hydrological data

Description: A method is described for jointly using time-lapse multiple-offset cross-borehole ground-penetrating radar (GPR) travel time measurements and hydrological measurements to estimate field-scale soil hydraulic parameters and parameters of the petrophysical function, which relates soil porosity and water saturation to the effective dielectric constant. We build upon previous work to take advantage of a wide range of GPR data acquisition configurations and to accommodate uncertainty in the petrophysical function. Within the context of water injection experiments in the vadose zone, we test our inversion methodology with synthetic examples and apply it to field data. The synthetic examples show that while realistic errors in the petrophysical function cause substantial errors in the soil hydraulic parameter estimates,simultaneously estimating petrophysical parameters allows for these errors to be minimized. Additionally, we observe in some cases that inaccuracy in the GPR simulator causes systematic error in simulated travel times, making necessary the simultaneous estimation of a correction parameter. We also apply the method to a three-dimensional field setting using time-lapse GPR and neutron probe (NP) data sets collected during an infiltration experiment at the U.S. Department of Energy (DOE) Hanford site in Washington. We find that inclusion of GPR data in the inversion procedure allows for improved predictions of water content, compared to predictions made using NP data alone.
Date: May 5, 2005
Creator: Kowalsky, Michael B.; Finsterle, Stefan; Peterson, John; Hubbard,Susan; Rubin, Yoram; Majer, Ernest et al.
Partner: UNT Libraries Government Documents Department

DataMover: robust terabyte-scale multi-file replication overwide-area networks

Description: Typically, large scientific datasets (order of terabytes) are generated at large computational centers, and stored on mass storage systems. However, large subsets of the data need to be moved to facilities available to application scientists for analysis. File replication of thousands of files is a tedious, error prone, but extremely important task in scientific applications. The automation of the file replication task requires automatic space acquisition and reuse, and monitoring the progress of staging thousands of files from the source mass storage system, transferring them over the network, archiving them at the target mass storage system or disk systems, and recovering from transient system failures. We have developed a robust replication system, called DataMover, which is now in regular use in High-Energy-Physics and Climate modeling experiments. Only a single command is necessary to request multi-file replication or the replication of an entire directory. A web-based tool was developed to dynamically monitor the progress of the multi-file replication process.
Date: April 5, 2004
Creator: Sim, Alex; Gu, Junmin; Shoshani, Arie & Natarajan, Vijaya
Partner: UNT Libraries Government Documents Department

Distributed Energy Resources at Naval Base Ventura County Building1512: A Sensitivity Analysis

Description: This report is the second of a two-part study by BerkeleyLab of a DER (distributed energy resources) system at Navy Base VenturaCounty (NBVC). First, a preliminary assessment ofthe cost effectivenessof distributed energy resources at Naval Base Ventura County (NBVC)Building 1512 was conducted in response to the base s request for designassistance to the Federal Energy Management Program (Bailey and Marnay,2004). That report contains a detailed description of the site and theDER-CAM (Consumer Adoption Model) parameters used. This second reportcontains sensitivity analyses of key parameters in the DER system modelof Building 1512 at NBVC and additionally considers the potential forabsorption-powered refrigeration.The prior analysis found that under thecurrent tariffs, and given assumptions about the performance andstructure of building energy loads and available generating technologycharacteristics, installing a 600 kW DER system with absorption coolingand recovery heat capabilities could deliver cost savings of about 14percent, worth $55,000 per year. However, under current conditions, thisstudy also suggested that significant savings could be obtained ifBuilding 1512 changed from its current direct access contract to a SCETOU-8 (Southern California Edison time of use tariff number 8) ratewithout installing a DER system. Evaluated on this tariff, the potentialsavings from installation of a DER system would be about 4 percent of thetotal bill, or $16,000 per year.
Date: June 5, 2005
Creator: Bailey, Owen C. & Marnay, Chris
Partner: UNT Libraries Government Documents Department

Acceleressence: Dark energy from a phase transition at the seesawscale

Description: Simple models are constructed for ''acceleressence'' dark energy: the latent heat of a phase transition occurring in a hidden sector governed by the seesaw mass scale v{sup 2}/M{sub Pl}, where v is the electroweak scale and M{sub Pl} the gravitational mass scale. In our models, the seesaw scale is stabilized by supersymmetry, implying that the LHC must discover superpartners with a spectrum that reflects a low scale of fundamental supersymmetry breaking. Newtonian gravity may be modified by effects arising from the exchange of fields in the acceleressence sector whose Compton wavelengths are typically of order the millimeter scale. There are two classes of models. In the first class the universe is presently in a metastable vacuum and will continue to inflate until tunneling processes eventually induce a first order transition. In the simplest such model, the range of the new force is bounded to be larger than 25 {micro}m in the absence of fine-tuning of parameters, and for couplings of order unity it is expected to be {approx} 100 {micro}m. In the second class of models thermal effects maintain the present vacuum energy of the universe, but on further cooling, the universe will ''soon'' smoothly relax to a matter dominated era. In this case, the range of the new force is also expected to be of order the millimeter scale or larger, although its strength is uncertain. A firm prediction of this class of models is the existence of additional energy density in radiation at the eV era, which can potentially be probed in precision measurements of the cosmic microwave background. An interesting possibility is that the transition towards a matter dominated era has occurred in the very recent past, with the consequence that the universe is currently decelerating.
Date: October 5, 2004
Creator: Chacko, Z.; Hall, Lawrence J. & Nomura, Yasunori
Partner: UNT Libraries Government Documents Department

A Compact High Gradient Pulsed Magnetic Quadpole

Description: A design for a high gradient, low inductance pulsed quadrupole magnet is presented. The magnet is a circular current dominated design with a circular iron return yoke. Conductor angles are determined by a method of direct multipole elimination which theoretically eliminates the first four higher order multipole field components. Coils are fabricated from solid round film-insulated conductor, wound as a single layer ''non-spiral bedstead'' coil having a diagonal leadout entirely within one upturned end. The coils are wound and stretched straight in a special winder, then bent in simple fixtures to form the upturned ends.
Date: July 5, 2005
Creator: Shuman, D.; Faltens, A.; Kajiyama, Y.; Kireeff-Covo, M. & Seidl, P.
Partner: UNT Libraries Government Documents Department

Results and commissioning issues from an automated demand responsepilot

Description: This paper describes a research project to develop and test Automated Demand Response hardware and software technology in large facilities. We describe the overall project and some of the commissioning and system design problems that took place. Demand Response (DR) is a set of activities to reduce or shift electricity use to improve the electric grid reliability purposes, manage electricity costs, and ensure that customers receive signals that encourage load reduction during times when the electric grid is near its capacity. There were a number of specific commissioning challenges in conducting this test including software compatibility, incorrect time zones, IT and EMCS failures, and hardware issues. The knowledge needed for this type of system commissioning combines knowledge of building controls with network management and knowledge of emerging information technologies.
Date: August 5, 2004
Creator: Piette, Mary Ann; Watson, Dave; Sezgen, Osman & Motegi, Naoya
Partner: UNT Libraries Government Documents Department

The KM phase in semi-realistic heterotic orbifold models

Description: In string-inspired semi-realistic heterotic orbifolds models with an anomalous U(1){sub X},a nonzero Kobayashi-Masakawa (KM) phase is shown to arise generically from the expectation values of complex scalar fields, which appear in nonrenormalizable quark mass couplings. Modular covariant nonrenormalizable superpotential couplings are constructed. A toy Z{sub 3} orbifold model is analyzed in some detail. Modular symmetries and orbifold selection rules are taken into account and do not lead to a cancellation of the KM phase. We also discuss attempts to obtain the KM phase solely from renormalizable interactions.
Date: July 5, 2000
Creator: Giedt, Joel
Partner: UNT Libraries Government Documents Department

Terahertz radiation from laser accelerated electron bunches

Description: Coherent terahertz and millimeter wave radiation from laser accelerated electron bunches has been measured. The bunches were produced by tightly focusing (spot diameter {approx} 6 {micro}m) a high peak power (up to 10 TW), ultra-short ({ge}50 fs) laser pulse from a high repetition rate (10 Hz) laser system (0.8 {micro}m), onto a high density (>10{sup 19} cm{sup -3}) pulsed gas jet of length {approx} 1.5 mm. As the electrons exit the plasma, coherent transition radiation is generated at the plasma-vacuum boundary for wavelengths long compared to the bunch length. Radiation in the 0.3-19 THz range and at 94 GHz has been measured and found to depend quadratically on the bunch charge. The measured radiated energy for two different collection angles is in good agreement with theory. Modeling indicates that optimization of this table-top source could provide more than 100 {micro}J/pulse. Together with intrinsic synchronization to the laser pulse, this will enable numerous applications requiring intense terahertz radiation. This radiation can also be used as a powerful tool for measuring the properties of laser accelerated bunches at the exit of the plasma accelerator. Preliminary spectral measurements indicates that bunches as short as 30-50 fs have been produced in these laser driven accelerators.
Date: January 5, 2004
Creator: Leemans, W.P.; van Tilborg, J.; Faure, J.; Geddes, C.G.R.; Toth, Cs.; Schroe der, C.B. et al.
Partner: UNT Libraries Government Documents Department

Algorithms for deriving crystallographic space-group information. II: Treatment of special positions

Description: Algorithms for the treatment of special positions in 3-dimensional crystallographic space groups are presented. These include an algorithm for the determination of the site-symmetry group given the coordinates of a point, an algorithm for the determination of the exact location of the nearest special position, an algorithm for the assignment of a Wyckoff letter given the site-symmetry group, and an alternative algorithm for the assignment of a Wyckoff letter given the coordinates of a point directly. All algorithms are implemented in ISO C++ and are integrated into the Computational Crystallography Toolbox. The source code is freely available.
Date: October 5, 2001
Creator: Grosse-Kunstleve, Ralf W. & Adams, Paul D.
Partner: UNT Libraries Government Documents Department

Development of an energy conservation voluntary agreement pilot project in the steel sector in Shandong

Description: China faces a significant challenge in the years ahead to continue to provide essential materials and products for a rapidly-growing economy while addressing pressing environmental concerns. Energy is a fundamental element of the national economy and the conditions of its use have a direct impact on China's ability to reach its sustainable development goals. China's industrial sector, which accounts for over 70 percent of the nation's total energy consumption each year, provides materials such as steel and cement that build the nation's roads, bridges, homes, offices and other buildings. Industrial products include bicycles, cars, buses, trains, ships, office equipment, appliances, furniture, packaging, pharmaceuticals, and many other components of everyday life in an increasingly modern society. This vital production of materials and products, however, comes with considerable problems. China's industrial sector is heavily dependent on the country's abundant, yet polluting, coal resources. Industrial production locally pollutes the air with emissions of particulates, carbon monoxide, sulfur dioxide, and nitrogen oxides, uses scarce water and oil resources, emits greenhouse gases contributing to the warming global atmosphere, and often produces hazardous and polluting wastes. Fostering innovative approaches to reduce the use of polluting energy resources and to diminish pollution from industrial production that are tailored to China's emerging market-based economy is one of the most important challenges facing the nation today. The pressures of rapid industrial production growth, continued environmental degradation, and increased competition create a situation that calls for a strategically-planned evolution of China's industries into world-class production facilities that are competitive, energy-efficient and less polluting. Such a transition requires the complete commitment of industrial enterprises and the government to work together to transform the industrial facilities of China. Internationally, such a transformation of the industrial sector has been realized in a number of countries using an innovative policy mechanism called Voluntary Agreements. ...
Date: February 5, 2004
Creator: Price, Lynn; Yun, Jiang; Worrell, Ernst; Wenwei, Du & Sinton, Jonathan E.
Partner: UNT Libraries Government Documents Department

Self-aggregation in scaled principal component space

Description: Automatic grouping of voluminous data into meaningful structures is a challenging task frequently encountered in broad areas of science, engineering and information processing. These data clustering tasks are frequently performed in Euclidean space or a subspace chosen from principal component analysis (PCA). Here we describe a space obtained by a nonlinear scaling of PCA in which data objects self-aggregate automatically into clusters. Projection into this space gives sharp distinctions among clusters. Gene expression profiles of cancer tissue subtypes, Web hyperlink structure and Internet newsgroups are analyzed to illustrate interesting properties of the space.
Date: October 5, 2001
Creator: Ding, Chris H.Q.; He, Xiaofeng; Zha, Hongyuan & Simon, Horst D.
Partner: UNT Libraries Government Documents Department

Baseline information development for energy smart schools -- applied research, field testing and technology integration

Description: The original scope of work was to obtain and analyze existing and emerging data in four states: California, Florida, New York, and Wisconsin. The goal of this data collection was to deliver a baseline database or recommendations for such a database that could possibly contain window and daylighting features and energy performance characteristics of Kindergarten through 12th grade (K-12) school buildings (or those of classrooms when available). In particular, data analyses were performed based upon the California Commercial End-Use Survey (CEUS) databases to understand school energy use, features of window glazing, and availability of daylighting in California K-12 schools. The outcomes from this baseline task can be used to assist in establishing a database of school energy performance, assessing applications of existing technologies relevant to window and daylighting design, and identifying future R&D needs. These are in line with the overall project goals as outlined in the proposal. Through the review and analysis of this data, it is clear that there are many compounding factors impacting energy use in K-12 school buildings in the U.S., and that there are various challenges in understanding the impact of K-12 classroom energy use associated with design features of window glazing and skylight. First, the energy data in the existing CEUS databases has, at most, provided the aggregated electricity and/or gas usages for the building establishments that include other school facilities on top of the classroom spaces. Although the percentage of classroom floor area in schools is often available from the databases, there is no additional information that can be used to quantitatively segregate the EUI for classroom spaces. In order to quantify the EUI for classrooms, sub-metering of energy usage by classrooms must be obtained. Second, magnitudes of energy use for electricity lighting are not attainable from the existing databases, nor are the ...
Date: August 5, 2004
Creator: Xu, Tengfang & Piette, Mary Ann
Partner: UNT Libraries Government Documents Department

Instrumentation optimization for positron emission mammography

Description: The past several years have seen designs for PET cameras optimized to image the breast, commonly known as Positron Emission Mammography or PEM cameras. The guiding principal behind PEM instrumentation is that a camera whose field of view is restricted to a single breast has higher performance and lower cost than a conventional PET camera. The most common geometry is a pair of parallel planes of detector modules, although geometries that encircle the breast have also been proposed. The ability of the detector modules to measure the depth of interaction (DOI) is also a relevant feature. This paper finds that while both the additional solid angle coverage afforded by encircling the breast and the decreased blurring afforded by the DOI measurement improve performance, the ability to measure DOI is more important than the ability to encircle the breast.
Date: June 5, 2003
Creator: Moses, William W. & Qi, Jinyi
Partner: UNT Libraries Government Documents Department

Effect of small-scale fractures on flow and transport processes at Yucca Mountain, Nevada

Description: Although many conceptual models for fracture-matrix interaction have been evaluated for Yucca Mountain site-characterization studies, the most widely used model is currently based on the dual-permeability concept. It was chosen for use in site-characterization partially because it has proved to be capable of matching many types of field observed data. Another consideration is that net infiltration rates at the site are estimated to be very low (on the order of millimeters/year), or close to saturated matrix hydraulic conductivity. Recent field studies and tests, in particular, fracture mapping data, collected along the walls of the underground tunnels reveal that there exists a significantly large variety in fracture sizes from centimeters to tens of meters. There is a considerable amount of small-scale fractures that have not been considered in the previous modeling studies. Although the majority of these small fractures may not contribute much to global flow and transport through the fracture-matrix system, they may provide large amounts of storage pore space and allow for additional connection areas for well-connected, large-scale fractures and surrounding matrix blocks, which ultimately affect fracture-matrix interactions. However, the currently used dual-permeability model is unable to include the potentially important effect of small fractures. To overcome the limitations of the dual-permeability approach, we have developed a triple-continuum conceptual model to investigate the impact of small-scale fractures on flow and transport processes in fractured rocks. This new conceptual model subdivides fractures into two types: large-scale and small-scale. Large-scale fractures are those responsible for global connections; small-scale fractures are those that provide large-fracture storage space and enhance the local connections to the matrix system without contributing to global flow or transport. Because the triple-continuum model is composed of the rock matrix and two types of fractures, it can be regarded as an extension of the traditional dual-permeability model. Using a ...
Date: December 5, 2002
Creator: Wu, Yu-Shu; Liu, H.H. & Bodvarsson, G.S.
Partner: UNT Libraries Government Documents Department

High resolution imaging of vadose zone transport using surface and crosswell ground penetrating radar methods

Description: To effectively clean up many contaminated sites there is a need for information on heterogeneities at scales ranging from one centimeter to tens of meters, as these features can alter contaminant transport significantly. At the Department of Energy's Hanford, Washington site heterogeneities of interest can range from localized phenomena such as silt or gravel lenses, fractures, clastic dikes, to large-scale lithologic discontinuities. In the vadose zone it is critical to understand the parameters controlling flow. These features have been suspected of leading to funneling and fingering, additional physical mechanisms that could alter and possibly accelerate the transport of contaminants to underlying groundwater. For example, it has been observed from the studies to date that over relatively short distances there are heterogeneities in the physical structure of the porous medium and structural differences between repacked soil cores and the field site from which the materials initially came (Raymond and Shdo, 1966). Analysis of cores taken from the vadose zone (i.e., soil surface to water table) has been useful in identifying localized zones of contamination. Unfortunately, these analyses are sparse (limited to a few boreholes) and extremely expensive. The high levels of radioactivity at many of the contaminated sites increase drilling and sample costs and analysis time. Cost of drilling and core analysis for the SX tank farm has exceeded $1M per borehole (50 meter deep) for sampling. The inability to track highly mobile species through the vadose zone highlights an important need: the need for methods to describe the complete vadose zone plume and to determine processes controlling accelerated contamination of groundwater at Hanford. A combination of surface and crosswell (i.e. borehole) geophysical measurements is one means to provide this information. The main questions addressed with the radar methods in this study are: (1) What parts of the vadose zone-groundwater system ...
Date: November 5, 2002
Creator: Williams, Kenneth H.; Kowalsky, Mike B. & Peterson, John E.
Partner: UNT Libraries Government Documents Department

Solutions of test problems for disposal of CO2 in saline aquifers

Description: This report presents detailed results for three flow problems involving CO2 migration in saline aquifers, that had been posed as part of an international code intercomparison study. Selected data for PVT properties of aqueous mixtures involving CO2 are given, and the dynamics of immiscible displacement of an aqueous phase by supercritical CO2 is discussed. Simulations were conducted with a version of the TOUGH2 general purpose reservoir simulator that includes a special property package for supercritical CO2. The results can serve as benchmarks for debugging numerical simulation models.
Date: March 5, 2003
Creator: Pruess, Karsten & Garcia, Julio
Partner: UNT Libraries Government Documents Department

Studies of the N=90 region: The decay of 154Eu to 154Gd

Description: The decay of {sup 154}Eu {yields} {sup 154}Gd has been studied by {gamma}-ray singles and {gamma}-{gamma} coincidence spectroscopy using an array of 20 Compton-suppressed Ge detectors. The primary goal of the work was to confirm or refute a large number of questionable features in the decay scheme: the outcome is the removal of 8 levels from the previously adopted scheme, with the result that a new type of collective band is revealed. Many weak decay branches for the decay are clarified. These results are critical for understanding the structure of {sup 154}Gd and the N = 90 isotones; and the improved completeness of the decay scheme contributes to the use of {sup 154}Eu as a metrological standard.
Date: December 5, 2003
Creator: Kulp, W.D.; Wood, J.L.; Krane, K.S.; Loats, J.; Schmelzenbach, P.; Stapels, C.J. et al.
Partner: UNT Libraries Government Documents Department