255 Matching Results

Search Results

A preliminary assessment of the electron cloud effect for the FNALmain injector upgrade

Description: We present results from a preliminary assessment, via computer simulations, of the electron cloud density for the FNAL main injector upgrade at injection energy. Assuming a peak value for secondary emission yield {delta}{sub max} = 1.3, we find a threshold value of the bunch population, N{sub b,th} {approx} 1.25 x 10{sup 11}, beyond which the electron-cloud density {rho}{sub e} reaches a steady-state level that is {approx}10{sup 4} times larger than for N{sub b} < N{sub b,th}, essentially neutralizing the beam, and leading to a tune shift {approx}0.05. Our investigation is limited to a field-free region and to a dipole magnet, both of which yield similar results for both N{sub b,th} and the steady-state value of {rho}{sub e}. Possible dynamical effects from the electron cloud on the beam, such as emittance growth and instabilities, remain to be investigated separately.
Date: June 28, 2005
Creator: Furman, M.A.
Partner: UNT Libraries Government Documents Department

Plasma Processing of Advanced Materials

Description: Plasma Processing of Advanced Materials The project had the overall objective of improving our understanding of the influences of process parameters on the properties of advanced superhard materials. The focus was on high rate deposition processes using thermal plasmas and atmospheric pressure glow discharges, and the emphasis on superhard materials was chosen because of the potential impact of such materials on industrial energy use and on the environment. In addition, the development of suitable diagnostic techniques was pursued. The project was divided into four tasks: (1) Deposition of superhard boron containing films using a supersonic plasma jet reactor (SPJR), and the characterization of the deposition process. (2) Deposition of superhard nanocomposite films in the silicon-nitrogen-carbon system using the triple torch plasma reactor (TTPR), and the characterization of the deposition process. (3) Deposition of films consisting of carbon nanotubes using an atmospheric pressure glow discharge reactor. (4) Adapting the Thomson scattering method for characterization of atmospheric pressure non-uniform plasmas with steep spatial gradients and temporal fluctuations. This report summarizes the results.
Date: February 28, 2005
Creator: Heberlein, Joachim, V.R.; Pfender, Emil & Kortshagen, Uwe
Partner: UNT Libraries Government Documents Department

Evaluation of Fluidized Bed Steam Reforming (FBSR) Technology for Sodium Bearing Wastes from Idaho and Hanford Using the Bench-Top Steam Reformer (BSR)

Description: Fluidized Bed Steam Reforming (FBSR) is being considered as a potential technology for the immobilization of a wide variety of radioactive wastes, but especially aqueous high sodium wastes at Hanford, Idaho National Engineering and Environmental Laboratory (INEEL), and the Savannah River Site (SRS). To help the Department of Energy (DOE) make informed decisions about this technology for sodium bearing wastes further experimental data are needed. All work described in this study has been performed with non-radioactive simulants and compared to non-radioactive pilot scale testing at other facilities. The desired plan is to provide a laboratory scale system that correlates to the pilot and plant scale systems such that the chemistry of Fluidized Bed Steam Reforming (FBSR) can be optimized on a small scale, then verified at the pilot scale. Once verified, this will enable laboratory scale demonstrations of actual radioactive wastes. The Savannah River National Laboratory (SRNL) developed the Bench-top Steam Reformer (BSR) to fill this need. The development of the BSR is the focus of this study. In addition, the characterization of the FBSR products produced in the BSR from simulants of the INEEL Sodium-Bearing Waste (SBW) stream and the Hanford Low Activity Waste (LAW) stream are documented and compared to pilot scale testing of these same simulants at the INEEL pilot-scale test system located at the Science Applications International Corporation (SAIC) Science and Technology Applications Research (STAR) Center in Idaho Falls, ID.
Date: February 28, 2005
Creator: PAUL, BURKET
Partner: UNT Libraries Government Documents Department

Influence of Pressure-gradient and Shear on Ballooning Stability in Stellarators

Description: Pressure-driven, ideal ballooning stability calculations are often used to predict the achievable plasma in stellarator configurations. In this paper, the sensitivity of ballooning stability to plasmas profile variations is addressed. A simple, semi-analytic method for expressing the ballooning growth rate, for each field line, as a polynomial function of the variation in the pressure gradient and the average magnetic shear from an original equilibrium has recently been introduced [Phys. Plasmas 11:9 (September 2004) L53]. This paper will apply the expression to various stellarator configurations and comment on the validity of various truncated forms of the polynomial expression. In particular, it is shown that in general it is insufficient to consider only the second order terms as previously assumed, and that higher order terms must be included to obtain accurate predictions of stability.
Date: February 28, 2005
Creator: Hudson, S.R.; Hegna, C.C. & Nakajima, N.
Partner: UNT Libraries Government Documents Department

A Revised Model for Dosimetry in the Human Small Intestine

Description: A new model for an adult human gastrointestinal tract (GIT) has been developed for use in internal dose estimations to the wall of the GIT and to the other organs and tissues of the body from radionuclides deposited in the lumenal contents of the five sections of the GIT. These sections were the esophasgus, stomach, small intestine, upper large intestine, and the lower large intestine. The wall of each section was separated from its lumenal contents.
Date: February 28, 2005
Creator: Poston, John; Bhuiyan, Nasir U.; Redd, R. Alex; Parham, Neil & Watson, Jennifer
Partner: UNT Libraries Government Documents Department

Final Technical Report

Description: The long term goal of this laboratory is to elucidate a detailed molecular description of the process of initiation of protein synthesis and its regulation. The specific goals of the project were: (1) development of an in vivo [{sup 32}P]- and/or [{sup 35}S]-labeling system for proteins using Arabidopsis suspension cells; (2) develop an in vitro protein synthesis assay from Arabidopsis suspension cells; (3) develop an assay for locating Arabidopsis kinases that phosphorylate the initiation factors; and (4) begin to identify Arabidopsis kinases that are involved in phosphorylation of the initiation factors.
Date: June 28, 2005
Creator: Browning, Karen S.
Partner: UNT Libraries Government Documents Department

Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Final Report

Description: Final report of 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. Mockups applied to design review of AP600/1000, Construction planning for AP 600, and AP 1000 maintenance evaluation. Proof of concept study also performed for GenIV PBMR models.
Date: February 28, 2005
Creator: Shaw, Timothy; Baratta, Anthony & Whisker, Vaughn
Partner: UNT Libraries Government Documents Department

Hybrid Micro-Electro-Mechanical Systems for Highly Reliable and Selective Characterization of Tank Waste

Description: The main objective of this research program is to develop robust and reliable micro-electro-mechanical sensing systems, based on microcantilevers (MCs), that can operate in liquid environments with high levels of sensitivity and selectivity. The chemical responses of MCs result from analyte-induced differential stress at the cantilever surfaces. We aim to employ various surface nanostructuring strategies that enhance these stresses and hence the degree of static bending of the cantilevers. Receptor phases as self assembled monolayers (SAMs) and thin films are being synthesized and tested to provide selectivity. Selectivity is chemically enhanced by using different phases on individual MCs in arrays and by adding a spectroscopic component, surface enhanced Raman spectrometry (SERS), in hybrid approaches to sensing. Significant progress was made in tasks that were listed in the work plan for DOE EMSP project ''Hybrid Micro-Electro-Mechanical Systems for Highly Reliable and Selective Characterization of Tank Waste''. Several project areas are listed below and discussed and referenced to our literature on the topics.
Date: December 28, 2005
Creator: Datskos, Panos G.; Sepaniak, Michael J.; Lavrik, Nickolay; Dutta, Pampa & Culha, Mustafa
Partner: UNT Libraries Government Documents Department

An Order-of-Magnitude Estimation of Benzene Concentration in Saltstone Vault

Description: The contents of Tank 48 that include the tetraphenylborate (TPB) precipitates of potassium and cesium will be grouted and stored in the Saltstone vault. The grouting process is exothermic, which should accelerate the decomposition of TPB precipitates eventually to benzene. Because the vault is not currently outfitted with an active ventilation system, there is a concern that a mixture of flammable gases may form in the vapor space of each cell filled with the curing grout. The purpose of this study was to determine if passive breathing induced by the diurnal oscillations of atmospheric pressure would provide any mitigating measure against potential flammability. Specifically, it was requested that a set of algorithms be developed that would predict the equilibrium concentration of benzene as a function of benzene generation rate, fill height, and the amplitude of the barometric pressure oscillations. These algorithms were to be derived based on several simplifying assumptions so that order of magnitude estimates could be made quickly for scoping purposes. This memo documents the resulting algorithms along with those key assumptions made. These algorithms were then applied to simulate several test cases, including the baseline case where the cell was filled to the maximum height of 25 ft at the bulk benzene generation rate of 3.4 g/hr.
Date: February 28, 2005
Creator: ALEXANDER, CHOI
Partner: UNT Libraries Government Documents Department

YUCCA Mountain project.

Description: This report describes the experimental work performed at Argonne National Laboratory (ANL) during fiscal year 2004 (FY 04) under the Bechtel SAIC Company, LLC (BSC) Memorandum Purchase Order (MPO), contract number B004210CM3X. Important results related to the technical bases, uncertainties, validation, and conservatism in current source term models are summarized below. An examination of specimens of commercial spent nuclear fuel (CSNF) that had been subjected to corrosion testing for up to 10 years under hydrologically unsaturated conditions was undertaken to elucidate radionuclide release pathways and mechanisms.
Date: March 28, 2005
Creator: Ebert, W. L.; Fortner, J. A.; Finch, R. J.; Jerden, J. L. & Cunnane, J. C.
Partner: UNT Libraries Government Documents Department

Ultrafast Spectroscopy of Delocalized Excited States of the Hydrated Electron

Description: Research under support of this grant has been focused on the understanding of highly delocalized ''conduction-band-like'' excited states of solvated electrons in bulk water, in water trapped in the core of reverse micelles, and in alkane solvents. We have strived in this work to probe conduction-band-like states by a variety of ultrafast spectroscopy techniques. (Most of which were developed under DOE support in a previous funding cycle.) We have recorded the optical spectrum of the hydrated electron for the first time. This was accomplished by applying a photo-detrapping technique that we had developed in a previous funding cycle, but had not yet been applied to characterize the actual spectrum. In the cases of reverse micelles, we have been investigating the potential role of conduction bands in the electron attachment process and the photoinduced detrapping, and have published two papers on this topic. Finally, we have been exploring solvated electrons in isooctane from various perspectives. All of these results strongly support the conclusion that optically accessible, highly delocalized electronic states exist in these various media.
Date: September 28, 2005
Creator: Barbara, Paul F.
Partner: UNT Libraries Government Documents Department

Fundamental Studies of Fluid Mechanics: Stability in Porous Media

Description: This work has been concerned with theoretical, computational and experimental studies of a variety of flow and transport problems that are of generic interest and applicability in energy-related and energy-intensive processes. These include the following. (1) Problems associated with oil recovery: the global economy continues to be dependent on the stable and predictable supply of oil and fossil fuels. This will remain the case for the near term, as current estimates are that world production of oil will peak between 2025 and 2100, depending on assumptions regarding growth. Most of these resources reside in porous rocks and other naturally occurring media. Studies of flow-induced instabilities are relevant to the areas of secondary and enhanced oil recovery. (2) Small scale and Stokes flows: flows in microgeometries and involving interfaces and surfactants are of interest in a myriad of energy-related contexts. These include: pore-level modeling of the fundamental processes by which oil held in porous materials is mobilized and produced; heating and cooling energy cycles involving significant expenditure of energy in conditioning of human environments, heat pipes, and compact heat exchangers; and energy efficiency in large scale separation processes such as distillation and absorption-processes that underlie the chemical process industries. (3) Coating flows: these are of interest in information technologies, including the manufacture of integrated circuits and data storage and retrieval devices. It is estimated that 50-70% of the starting raw materials and intermediate devices in information technology processes must be discarded as a result of imperfections and failure to meet specifications. These in turn are often the result of the inability to control fluid-mechanical processes and flow instabilities. Our work over the grant period is primarily fundamental in nature. We are interested in establishing general principles and behaviors that relate to a variety of processes in a variety of contexts. Our ...
Date: April 28, 2005
Creator: Homsy, George M.
Partner: UNT Libraries Government Documents Department

The Impacts of Uranium and Thorium on the Defense Waste Processing Facility (DWPF) Viscosity Model

Description: The Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) vitrifies high level liquid waste (HLLW) into borosilicate glass for stabilization and permanent disposal. The viscosity of the borosilicate glass melt as a function of temperature is the single most important variable affecting the melt rate and pour ability of the glass. The viscosity determines the rate of melting of the raw feed, the rate of glass bubble release (foaming and fining), the rate of homogenization, the adequacy of heat transfer, the devitrification rate, and thus, the quality (in terms of glass homogeneity) of the final glass product. If the viscosity is too low, excessive convection currents can occur during melting, increasing corrosion/erosion of the melter materials of construction (refractory and electrodes) and making control of the melter more difficult. The lowest glass viscosities allowed in the DWPF melter have, therefore, been determined to be approximately 20 poise. DWPF glasses must pour continuously into a large steel canister for ultimate storage in a geologic repository, but glasses with a viscosity greater than or equal to 500 poise do not readily pour. Moreover, too high a viscosity can reduce product quality by causing voids in the final glass. A conservative range of 20-110 poise at a melt temperature, Tmelt or Tm, of 1150 degrees C was, therefore, established for DWPF production. In summary, a uranium term is not needed in the DWPF viscosity model as long as the U3O8 concentrations of the glasses being melted are less than or equal to 5.76 wt percent, the maximum value examined in this study. The fact that a U-plus-6 term is not needed in the DWPF viscosity model is consistent with the fact that U-plus-6 has four bridging and two non-bridging oxygen bonds. Therefore, the impact of the number of bridging and ...
Date: February 28, 2005
Creator: CAROL, JANTZEN
Partner: UNT Libraries Government Documents Department

Real-Time Water Quality Monitoring and Habitat Assessment in theSan Luis National Wildlife Refuge

Description: The project report describes a two year experiment to control wetland drainage to the San Joaquin River of California from the San Luis National Wildlife Refuge using a decision support system for real-time water quality management. This system required the installation and operation of one inlet and three drainage flow and water quality monitoring stations which allowed a simple mass balance model to be developed of the seasonally managed wetlands in the study area. Remote sensing methods were developed to document long-term trends in wetland moist soil vegetation and soil salinity in response to management options such as delaying the initiation of seasonal wetland drainage. These environmental management tools provide wetland managers with some of the tools necessary to improve salinity conditions in the San Joaquin River and improve compliance with State mandated salinity objectives without inflicting long-term harm on the wild fowl habitat resource.
Date: August 28, 2005
Creator: Quinn, Nigel W.T.; Hanlon, Jeremy S.; Burns, Josephine R.; Stromayer, Karl A.K.; Jordan, Brandon M.; Ennis, Mike J. et al.
Partner: UNT Libraries Government Documents Department

Potential Water and Energy Savings from Showerheads

Description: This paper estimates the benefits and costs of six water reduction scenarios. Benefits and costs of showerhead scenarios are ranked in this paper by an estimated water reduction percentage. To prioritize potential water and energy saving scenarios regarding showerheads, six scenarios were analyzed for their potential water and energy savings and the associated dollar savings to the consumer.
Date: September 28, 2005
Creator: Biermayer, Peter J.
Partner: UNT Libraries Government Documents Department

Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Task 5 Report: Generation IV Reactor Virtual Mockup Proof-of-Principle Study

Description: Task 5 report is part of a 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. Created a virtual mockup of PBMR reactor cavity and discussed applications of virtual mockup technology to improve Gen IV design review, construction planning, and maintenance planning.
Date: February 28, 2005
Creator: Shaw, Timothy; Baratta, Anthony & Whisker, Vaughn
Partner: UNT Libraries Government Documents Department

DOE final technical report 3/1997 to 2/2005

Description: DOE final technical report 3/1997 to 2/2005 This grant supported basic theoretical research into the derivation (from relativistic field theories) of relativistic equations for few body systems, with practical applications to the properties of 2 and 3 nucleon systems and to the nature of few-quark systems.
Date: November 28, 2005
Creator: Gross, Franz, L.
Partner: UNT Libraries Government Documents Department

LIFETIME PREDICTIONS OF TOXIC AND RADIOACTIVE WASTE DISPOSAL AND REMEDIATION SCHEMES

Description: Nuclear power production epitomizes the need for predictive geoscience (Ewing, 2004). Current global carbon emissions of {approx}7 Gt/y, largely from fossil fuel consumption, are expected to grow and result in a variety of adverse global effects, including acid rain, toxic smog, and hypothetically, sea level rise and increased frequency and severity of adverse weather conditions. One of the most reliable and sufficiently large alternative sources of energy is nuclear power, which currently provides about 17% of the world's electricity, equivalent to a reduction in carbon emissions of {approx}0.5 Gt/y. The U.S. currently consumes {approx}40% of the world's fossil fuel production, but generates only about 20% of it's electricity from nuclear plants. One major factor inhibiting increased power production form this source in the US. is the lack of a licensed repository for spent nuclear fuel, and Yucca Mountain is the only site being considered at this time. The licensing issue hinges on DOE's ability to present a credible case before the Nuclear Regulatory Commission that releases of radionuclides from the repository will not pose a threat to the accessible environment. This case is being built using a performance assessment model that incorporates a thermochemical database (EQ3/6) fed by experiments and theoretical developments in aqueous geochemistry and fluid rock interactions, coupled reaction/transport models which combine both the chemical and physical aspects of fluid and heat transport through porous and fractured media, geohazard and climate change models, and information gleaned from natural analogs. The assessment period is currently 10,000 years, but this has recently been challenged in a court of law, and may be extended to 300,000 years or more. Yucca Mountain has a design capacity that only marginally exceeds the current U.S. inventory of commercial spent fuel, currently stored on site at power plants through the country. Some analysts suggest that ...
Date: June 28, 2005
Creator: Wesolowski, D.J.; Ewing, R.C. & Bruno, J.
Partner: UNT Libraries Government Documents Department

A Dipole Assisted IEC Neutron Source

Description: A potential opportunity to enhance Inertial Electrostatic Confinement (IEC) fusion exists by augmenting it with a magnetic dipole configuration. The theory is that the dipole fields will enhance the plasma density in the center region of the IEC and the combined IEC and dipole confinement properties will reduce plasma losses. To demonstrate that a hybrid Dipole-IEC configuration can provide an improved neutron source vs. a stand alone IEC, a first model Dipole-IEC experiment was benchmarked against a reference IEC. A triple Langmuir probe was used to find the electron temperature and density. It was found that the magnetic field increases the electron density by a factor of 16, the electron temperature decreases in the presence of a magnetic field, the discharge voltage decreases in the presence of a magnetic field, the potential of the dipole strongly influences the densities obtained in the center. The experimental set-up and plasma diagnostics are discussed in detail, as well as the results, and the developmental issues.
Date: November 28, 2005
Creator: Shrestha, Prajakti Joshi
Partner: UNT Libraries Government Documents Department

Ultrahigh Sensitivity Heavy Noble Gas Detectors for Long-Term Monitoring and for Monitoring Air

Description: The primary objective of this research project is to develop heavy noble gas (krypton, xenon, and radon) detectors for (1) long-term monitoring of transuranic waste, spent fuel, and other uranium and thorium bearing wastes and (2) alpha particle air monitors that discriminate between radon emissions and other alpha emitters. DOE needs that are addressed by this project include improved long-term monitoring capability and improved air monitoring capability during remedial activities. Successful development and implementation of the proposed detection systems could significantly improve current capabilities with relatively simple and inexpensive equipment.
Date: July 28, 2005
Creator: Valentine, John D.
Partner: UNT Libraries Government Documents Department

Design of Radiation-Tolerant Structural Alloys for Generation IV Nuclear Energy Systems

Description: The objective of this program is to improve the radiation tolerance of both austenitic and ferritic-martensitic (F-M) alloys projected for use in Generation IV systems. The expected materials limitations of Generation IV components include: creep strength, dimensional stability, and corrosion/stress corrosion compatibility. The material design strategies to be tested fall into three main categories: (1) engineering grain boundaries; (2) alloying, by adding oversized elements to the matrix; and (3) microstructural/nanostructural design, such as adding matrix precipitates. These three design strategies were tested across both austenitic and ferritic-martensitic alloy classes
Date: December 28, 2005
Creator: Allen, T. R.; Was, G. S.; Bruemmer, S. M.; Gan, J. & Ukai, S.
Partner: UNT Libraries Government Documents Department

A Game Theoretic Approach to Cyber Attack Prediction

Description: The area investigated by this project is cyber attack prediction. With a focus on correlation-based prediction, current attack prediction methodologies overlook the strategic nature of cyber attack-defense scenarios. As a result, current cyber attack prediction methodologies are very limited in predicting strategic behaviors of attackers in enforcing nontrivial cyber attacks such as DDoS attacks, and may result in low accuracy in correlation-based predictions. This project develops a game theoretic framework for cyber attack prediction, where an automatic game-theory-based attack prediction method is proposed. Being able to quantitatively predict the likelihood of (sequences of) attack actions, our attack prediction methodology can predict fine-grained strategic behaviors of attackers and may greatly improve the accuracy of correlation-based prediction. To our best knowledge, this project develops the first comprehensive framework for incentive-based modeling and inference of attack intent, objectives, and strategies; and this project develops the first method that can predict fine-grained strategic behaviors of attackers. The significance of this research and the benefit to the public can be demonstrated to certain extent by (a) the severe threat of cyber attacks to the critical infrastructures of the nation, including many infrastructures overseen by the Department of Energy, (b) the importance of cyber security to critical infrastructure protection, and (c) the importance of cyber attack prediction to achieving cyber security.
Date: November 28, 2005
Creator: Liu, Peng
Partner: UNT Libraries Government Documents Department