Neutronics and shielding analysis of the National Ignition Facility (open access)

Neutronics and shielding analysis of the National Ignition Facility

The Department of Energy (DOE) is proposing to construct the National Ignition Facility (NIF) by the year 2001 to embark on a program to achieve ignition and modest gain in the laboratory. The NIF will use 1.8 MJ of 0.35 {mu}m laser light, nearly a fifty-fold increase in energy over the Nova laser at Lawrence Livermore National Laboratory (LLNL). A 5-m radius spherical aluminum chamber will contain the target experiments and allow access to diagnostics for data collection. Based on a projected maximum annual yield of 385 MJ (1.4 {times} 10{sup 20} 14 MeV neutrons), prompt annual doses will be < 1.2 {mu}Sv at the nearest site boundary, < 0.43 mSv immediately outside the Target Area, and < 30 {mu}Sv in the war-room and control room. The target chamber material has been selected in a trade-off between its mechanical properties and its neutron activation qualities. External target chamber shielding has been selected such that the total annual occupational dose to Target Area workers will be {le} 5 mSv. Finally, some Target Area systems have been redesigned based on their neutron activation and residual dose rates. The operation of the NIF will have an insignificant impact to workers and the general …
Date: June 1, 1994
Creator: Latkowski, J. F.; Tobin, M. T. & Singh, M. S.
System: The UNT Digital Library
Three neural network based sensor systems for environmental monitoring (open access)

Three neural network based sensor systems for environmental monitoring

Compact, portable systems capable of quickly identifying contaminants in the field are of great importance when monitoring the environment. One of the missions of the Pacific Northwest Laboratory is to examine and develop new technologies for environmental restoration and waste management at the Hanford Site. In this paper, three prototype sensing systems are discussed. These prototypes are composed of sensing elements, data acquisition system, computer, and neural network implemented in software, and are capable of automatically identifying contaminants. The first system employs an array of tin-oxide gas sensors and is used to identify chemical vapors. The second system employs an array of optical sensors and is used to identify the composition of chemical dyes in liquids. The third system contains a portable gamma-ray spectrometer and is used to identify radioactive isotopes. In these systems, the neural network is used to identify the composition of the sensed contaminant. With a neural network, the intense computation takes place during the training process. Once the network is trained, operation consists of propagating the data through the network. Since the computation involved during operation consists of vector-matrix multiplication and application of look-up tables unknown samples can be rapidly identified in the field.
Date: May 1, 1994
Creator: Keller, P. E.; Kouzes, R. T. & Kangas, L. J.
System: The UNT Digital Library
Characterization of nova plasmas using an x-ray spectrometer with temporal and spatial resolution (open access)

Characterization of nova plasmas using an x-ray spectrometer with temporal and spatial resolution

Spectroscopic diagnostics have great potential to obtain high temperature measurements of plasmas created in ICF targets. The plasmas may be over 1 mm in size and therefore, one of the first steps in making accurate spectroscopic measurements has been to improve the resolution of the instrument. A spectrograph is now available for Nova experiments which takes advantage of gated technology by coupling a Bragg crystal to a microchannel plate that can record data over a 250 ps time frame. The crystal disperses the x-rays, while slits add the ability to image the plasmas in the perpendicular direction. The characteristics of this diagnostic, TSPEC, will be evaluated for laser-produced plasmas. Recent data will be presented from colliding plasmas and large-scale hohlraums which indicate that imaging can greatly enhance the ability to diagnose these plasmas.
Date: May 1, 1994
Creator: Back, C. A.; Kauffman, R. L.; Bell, P. & Kilkenny, J. D.
System: The UNT Digital Library
Chloride and mercury monitors for air toxics measurements (open access)

Chloride and mercury monitors for air toxics measurements

Ames laboratory will develop an integrated sampling and analysis system suitable for on-line monitoring of hydrogen chloride (HCl) and mercury (Hg) in advanced coal gasifiers. The objectives of this project are to (1) summarize current technology for monitoring HCl and Hg in gaseous effluents, (2) identify analytical techniques for such determinations in high-temperature, high-pressure gases from coal-based systems of interest to METC for producing electrical power, (3) evaluate promising analytical approaches, and (4) produce reliable on-line monitors which are adaptable to plant-scale diagnostics and process control.
Date: October 1, 1994
Creator: Buttermore, W. H.; Norton, G. A.; Chriswell, C. D.; Eckels, D. E. & Peters, R. E.
System: The UNT Digital Library
Development of superplasticity in 5083 aluminum with additions of Mn and Zr (open access)

Development of superplasticity in 5083 aluminum with additions of Mn and Zr

The superplastic behavior of the 5083 aluminum alloy with additions of Mn and Zr was studied by uniaxial tensile testing and microstructural evaluations. Additions of up to 0.2% Zr and 0.8% Mn were made to a base 5083 aluminum alloy to decrease the grain size and improve superplastic behavior. Constant strain-rate tensile test data were used to determine strain-rate sensitivity (m values) and elongations-to-failure for the alloys at strain rates ranging from 4 {times} 10{sup {minus}4} to 1 {times} 10{sup {minus}1} s{sup {minus}1} at temperatures of 450 to 550C. Elongations-to-failure of up to 400% at 1 {times} 10{sup {minus}2} s{sup {minus}1} were achieved for the modified alloys. The strain-rate sensitivity for the alloys as a function of strain was determined and two distinct behaviors were observed. For the alloys having composition close to the base 5083 alloy, the m value steadily decreased with increasing strain; however, in alloys with higher levels of Zr, the m value remained stable. A maximum m value of 0.65 was achieved at 0.7 strain for the 1.6% Mn and 0.2% Zr alloy at 1 {times} 10{sup {minus}3} s{sup {minus}1}.
Date: May 1, 1994
Creator: Lavender, C. A.; Vetrano, J. S.; Smith, M. T.; Bruemmer, S. M. & Hamilton, C. H.
System: The UNT Digital Library
Carbon taxes and India (open access)

Carbon taxes and India

Using the Indian module of the Second Generation Model 9SGM, we explore a reference case and three scenarios in which greenhouse gas emissions were controlled. Two alternative policy instruments (carbon taxes and tradable permits) were analyzed to determine comparative costs of stabilizing emissions at (1) 1990 levels (the 1 X case), (2) two times the 1990 levels (the 2X case), and (3) three times the 1990 levels (the 3X case). The analysis takes into account India`s rapidly growing population and the abundance of coal and biomass relative to other fuels. We also explore the impacts of a global tradable permits market to stabilize global carbon emissions on the Indian economy under the following two emissions allowance allocation methods: (1) {open_quotes}Grandfathered emissions{close_quotes}: emissions allowances are allocated based on 1990 emissions. (2) {open_quotes}Equal per capita emissions{close_quotes}: emissions allowances are allocated based on share of global population. Tradable permits represent a lower cost method to stabilize Indian emissions than carbon taxes, i.e., global action would benefit India more than independent actions.
Date: July 1, 1994
Creator: Fisher-Vanden, K. A.; Pitcher, H. M.; Edmonds, J. A.; Kim, S. H. & Shukla, P. R.
System: The UNT Digital Library
Investigation of the generation of several long-lived radionuclides of importance in fusion reactor technology: Report on a Coordinated Research Program sponsored by the International Atomic Energy Agency (open access)

Investigation of the generation of several long-lived radionuclides of importance in fusion reactor technology: Report on a Coordinated Research Program sponsored by the International Atomic Energy Agency

The IAEA initiated a Coordinated Research Program (CRP) in 1988 to obtain reliable information for 16 long-lived activation reactions of special importance to fusion reactor technology: {sup 27}Al (n, 2n){sup 26}Al, {sup 63}Cu(n,p){sup 63}Ni, {sup 94}Mo(n,p) {sup 94}Nb, {sup 109}Ag(n,2n){sup 108m}Ag, {sup 179}Hf(n,2n) {sup 178m2}Hf, {sup 182}W(n,n{sup `}a){sup 178m2}Hf, {sup 151}Eu(n,2n) {sup 150}gEu, {sup 153}Eu(n,2n){sup 152+m2}Eu, {sup 159}Tb(n, 2n){sup 158}Tb, {sup 158}Dy(n,p){sup 158}Tb, {sup 193}Ir(n,2n) {sup 192m2}Ir, {sup 187}Re(n,2n){sup 186m}Re, {sup 62}Ni(n{gamma}) {sup 63}Ni, {sup 98}Mo(n,{gamma}){sup 99}Mo({beta}-){sup 99}Tc, {sup 165}Ho(n,{gamma}) {sup 166m}Ho and {sup 191}Ir(n,{gamma}){sup 192m2}Ir. this paper documents progress achieved from the start of the program through mid- 1993.
Date: May 1, 1994
Creator: Smith, D. L. & Pashchenko, A. B.
System: The UNT Digital Library
24th Annual Anomalous Absorption Conference. Book of Abstracts (open access)

24th Annual Anomalous Absorption Conference. Book of Abstracts

This report contains abstracts on topics in the following areas: parametric instabilities; hohlraum physics; laser plasma physics with short pulses; and rayleigh-taylor instability and hydrodynamics.
Date: August 1, 1994
Creator: unknown
System: The UNT Digital Library
Computer animation of clouds (open access)

Computer animation of clouds

Computer animation of outdoor scenes is enhanced by realistic clouds. I will discuss several different modeling and rendering schemes for clouds, and show how they evolved in my animation work. These include transparency-textured clouds on a 2-D plane, smooth shaded or textured 3-D clouds surfaces, and 3-D volume rendering. For the volume rendering, I will present various illumination schemes, including the density emitter, single scattering, and multiple scattering models.
Date: January 28, 1994
Creator: Max, N.
System: The UNT Digital Library
Projection Gas Immersion Laser Doping (P-GILD): A resistless, nanosecond thermal doping/diffusion technology (open access)

Projection Gas Immersion Laser Doping (P-GILD): A resistless, nanosecond thermal doping/diffusion technology

Projection Gas Immersion Laser Doping (P-GILD) is an innovative doping process that utilizes finely patterned excimer laser light to thermally process discreet regions within an integrated circuit. By reducing the total temperature cycle to nanoseconds and localizing the thermal energy in depth and area, P-GILD fundamentally changes the junction formation process. This paper first reviews the general characteristics of the P-GILD process and equipment. Two variations of the technique, melt and non-melt, and their resulting junction characteristics are then described in detail. The combination of the two laser processes along with the simplification that a resistless technology brings to the process sequence, enables efficient fabrication of impurity profiles that are ideal for a wide array of transistor applications.
Date: July 27, 1994
Creator: Weiner, K. H.
System: The UNT Digital Library
Hydrology and ecology of pinyon-juniper woodlands: Conceptual framework and field studies (open access)

Hydrology and ecology of pinyon-juniper woodlands: Conceptual framework and field studies

Pinyon-juniper woodlands represent an important ecosystem in the semiarid western United States. Concern over the sustainability of, and management approaches for, these woodlands is increasing. As in other semiarid environments, water dynamics and vegetation patterns in pinyon-juniper woodlands are highly interrelated. An understanding of these relationships can aid in evaluating various management strategies. In this paper we describe a conceptual framework designed to increase our understanding of water and vegetation in pinyon-juniper woodlands. The framework comprises five different scales, at each of which the landscape is divided into {open_quotes}functional units{close_quotes} on the basis of hydrologic characteristics. The hydrologic behavior of each unit and the connections between units are being evaluated using an extensive network of hydrological and ecological field studies on the Pajarito Plateau in northern New Mexico. Data from these studies, coupled with application of the conceptual model, have led to the development of a number of hypotheses concerning the interrelationships of water and vegetation in pinyon-juniper woodlands.
Date: September 1, 1994
Creator: Wilcox, B. P. & Breshears, D. D.
System: The UNT Digital Library
Survey of proposed high intensity accelerators and their applications (open access)

Survey of proposed high intensity accelerators and their applications

Many interesting applications are being considered for high intensity accelerators. Implications of the technology developments that are enhancing these opportunities, or making them possible, will be covered in context of the applications. Applications include those for research (in areas such as material science, biological sciences, nuclear and high energy physics), accelerator-driven transmutation technologies, defense, and medicine. Specific examples will be used to demonstrate the impact that technology development can have and how transfer of this technology to industry can have an impact in the consumer and commercial arenas. Technology Development in rf power, controls, beam optics, rf structures, magnets, injectors, and beam halos will be considered.
Date: September 1, 1994
Creator: Schriber, S. O.
System: The UNT Digital Library
Simulation and analysis of laser guide star adaptive optics systems for the eight to ten meter class telescopes (open access)

Simulation and analysis of laser guide star adaptive optics systems for the eight to ten meter class telescopes

This paper discusses the design and analysis of laser-guided adaptive optic systems for the large, 8--10 meter class telescopes. We describe a technique for calculating the expected modulation transfer function and the point spread function for a closed loop adaptive optics system, parameterized by the degree of correction and the seeing conditions. The results agree closely with simulations and experimental data, and validate well known scaling law models even at low order correction. Scaling law.model analysis of a proposed adaptive optics system at the Keck telescope leads to the conclusion that a single laser guide star beacon will be adequate for diffraction limited imaging at wavelengths between 1 and 3 am with reasonable coverage of the sky. Cone anisoplanatism will dominate wavefront correction error at the visible wavelengths unless multiple laser guide stars are used.
Date: March 1, 1994
Creator: Gavel, D. T. & Olivier, S. S.
System: The UNT Digital Library
Proceedings of the International Workshop on Low Energy Muon Science: LEMS`93 (open access)

Proceedings of the International Workshop on Low Energy Muon Science: LEMS`93

This report contains papers on research with low energy muons. Topics cover fundamental electroweak physics; muonic atoms and molecules, and muon catalyzed fusion; muon spin research; and muon facilities. These papers have been indexed and cataloged separately.
Date: January 1, 1994
Creator: Leon, M.
System: The UNT Digital Library
Recent results from Fermilab E-687, charm particle decays, lifetimes and photoproduction dynamics: A compilation results presented at DPF 1994 (open access)

Recent results from Fermilab E-687, charm particle decays, lifetimes and photoproduction dynamics: A compilation results presented at DPF 1994

This report contains papers on the following topics: Recent results on the semi-leptonic decay Decay D{sup 0} {yields} K{sup {minus}}{mu}{sup +}{nu}{sub {mu}}; charmed mesons; observation of the Decay {Omega}{sub c}{sup 0}{Sigma}{sup +}K{sup {minus}}K{sup {minus}}{phi}{sup +}; the physics of charm lifetimes; and photoproduction of charmed hadrons. These papers have been cataloged separately.
Date: October 1, 1994
Creator: Collaboration, E687
System: The UNT Digital Library
Dip-moveout processing by Fourier transform in anisotropic media (open access)

Dip-moveout processing by Fourier transform in anisotropic media

Conventional dip-moveout (DMO) processing is designed for isotropic media and cannot handle angle-dependent velocity. The authors show that Hale`s isotropic DMO algorithm remains valid for elliptical anisotropy but may lead to serious errors for non-elliptical transversely isotropic models, even if velocity anisotropy is moderate. Here, they present an extension of Hale`s constant-velocity DMO method to anisotropic media. The DMO operator, to be applied to normal-moveout (NMO) corrected data, is based on the analytic expression for NMO velocity for dipping reflectors given by Tsvankin (1995a). Since the anisotropic DMO depends on the elastic parameters of the medium, it should be preceded by an inversion procedure designed to obtain the NMO velocity as a function of ray parameter. Another complication introduced by anisotropy is the influence of nonhyperbolic moveout not accounted for in the DMO operator. However, for spreads typical in conventional acquisition design, deviations from hyperbolic moveout for P-waves are not significant. Impulse responses and synthetic examples for typical transversely isotropic models with a vertical symmetry axis (VTI) demonstrate the accuracy and efficiency of this DMO technique. Once the inversion step has been completed, the NMO-DMO sequence does not take any more computing time than that for the generic Hale`s method …
Date: December 1994
Creator: Anderson, John & Tsvankin, Ilya
System: The UNT Digital Library
Over the energy edge: Results from a seven year new commercial buildings research and demonstration project (open access)

Over the energy edge: Results from a seven year new commercial buildings research and demonstration project

Edge was a research oriented demonstration project that began in 1985. Twenty-eight commercial buildings were designed and constructed to use 30% less electricity than a hypothetical simulated baseline building. Average savings from the 18 buildings evaluated with post-occupancy, ``tuned`` simulation models were less, at 17%. The cost-effectiveness of the energy-efficiency measures at six of the 18 projects met the target cost-of-conserved (CCE) energy of 5.6cent/kWh for the total package of measures. The most important reason energy savings were not as great as predicted is that the actual, installed energy-efficiency measures and building characteristics changed from the design assumptions. The cost effectiveness of the measures would have been greater if the baseline was common practice rather than assumptions based on the regional building code. For example, the Energy Edge small offices use about 30% to 50% less energy than comparable new buildings. Savings also would have been greater if commissioning had been included within the program. Future projects should consider lower-cost ``hands-on`` evaluation techniques that provide direct feedback on measure performance based on functional and diagnostic testing, with annual check-ups to ensure persistence of savings.
Date: August 1994
Creator: Piette, M. A.; Nordman, B.; deBuen, O.; Diamond, R. & Codey, B.
System: The UNT Digital Library
Fifth international conference on hyperbolic problems -- theory, numerics, applications: Abstracts (open access)

Fifth international conference on hyperbolic problems -- theory, numerics, applications: Abstracts

The conference demonstrated that hyperbolic problems and conservation laws play an important role in many areas including industrial applications and the studying of elasto-plastic materials. Among the various topics covered in the conference, the authors mention: the big bang theory, general relativity, critical phenomena, deformation and fracture of solids, shock wave interactions, numerical simulation in three dimensions, the level set method, multidimensional Riemann problem, application of the front tracking in petroleum reservoir simulations, global solution of the Navier-Stokes equations in high dimensions, recent progress in granular flow, and the study of elastic plastic materials. The authors believe that the new ideas, tools, methods, problems, theoretical results, numerical solutions and computational algorithms presented or discussed at the conference will benefit the participants in their current and future research.
Date: December 31, 1994
Creator: unknown
System: The UNT Digital Library
Processing and properties of iridium alloys for space power applications (open access)

Processing and properties of iridium alloys for space power applications

Iridium alloys are used as fuel cladding in radioisotope thermoelectric generators due to their high-melting point, high- temperature strength, and oxidation and corrosion resistance. Although iridium has a face-centered cubic crystal structure, it undergoes a distinct ductile-to-brittle transition characteristic of many body-centered cubic metals. Improved ductility in the alloys is achieved through material purification and controlled alloy additions at the parts per million (ppm) level. A vacuum arc remelt operation produces a nearly defect-free casting, which is further processed to sheet products. A change in processing from drop castings of small arc-melted buttons to large arc-remelted ingots has substantially improved product yields. The effects of processing changes on alloy microstructure, sheet textures, oxidation effects, high-strain-rate ductility, and fabricability are discussed.
Date: December 31, 1994
Creator: Ohriner, E. K.
System: The UNT Digital Library
59. Cold Spring Harbor symposium on quantitative biology: Molecular genetics of cancer (open access)

59. Cold Spring Harbor symposium on quantitative biology: Molecular genetics of cancer

Investigation of the mechanistic aspects of cancer has its roots in the studies on tumor viruses and their effects on cell proliferation, function, and growth. This outstanding progress was well documented in previous Cold Spring Harbor Symposia on Quantitative Biology. In the early to mid 1980s, progress on the development of chromosome mapping strategies and the accumulation of DNA probes that identified polymorphisms, encouraged by the international Human Genome Project, enabled the identification of other genes that contributed to familial inheritance of high susceptibility to specific cancers. This approach was very successful and led to a degree of optimism that one aspect of cancer, the multistep genetic process from early neoplasia to metastatic tumors, was beginning to be understood. It therefore seemed appropriate that the 59th Symposium on Quantitative Biology focus attention on the Molecular Genetics of Cancer. The concept was to combine the exciting progress on the identification of new genetic alterations in human tumor cells with studies on the function of the cancer gene products and how they go awry in tumor cells.
Date: December 31, 1994
Creator: unknown
System: The UNT Digital Library
Parallel solid mechanics codes at Sandia National Laboratories (open access)

Parallel solid mechanics codes at Sandia National Laboratories

Computational physicists at Sandia National Laboratories have moved their production codes to distributed memory parallel computers. The codes include the multi-material CTH Eulerian code, structural mechanics code. This presentation discusses our experiences moving the codes to parallel computers and experiences running the codes. Moving large production codes onto parallel computers require developing parallel algorithms, parallel data bases and parallel support tools. We rewrote the Eulerian CTH code for parallel computers. We were able to move both ALEGRA and PRONTO to parallel computers with only a modest number of modifications. We restructured the restart and graphics data bases to make them parallel and minimize the I/O to the parallel computer. We developed mesh decomposition tools to divide a rectangular or arbitrary connectivity mesh into sub-meshes. The sub-meshes map to processors and minimize the communication between processors. We developed new visualization tools to process the very large, parallel data bases. This presentation also discusses our experiences running these codes on Sandia`s 1840 compute node Intel Paragon, 1024 processor nCUBE and networked workstations. The parallel version of CTH uses the Paragon and nCUBE for production calculations. The ALEGRA and PRONTO codes are moving off networked workstations onto the Paragon and nCUBE massively parallel …
Date: August 1, 1994
Creator: McGlaun, M.
System: The UNT Digital Library
Managing cumulative impacts: A key to sustainability? (open access)

Managing cumulative impacts: A key to sustainability?

This paper addresses how science can be more effectively used in creating policy to manage cumulative effects on ecosystems. The paper focuses on the scientific techniques that we have to identify and to assess cumulative impacts on ecosystems. The term ``sustainable development`` was brought into common use by the World Commission on Environment and Development (The Brundtland Commission) in 1987. The Brundtland Commission report highlighted the need to simultaneously address developmental and environmental imperatives simultaneously by calling for development that ``meets the needs of the present generation without compromising the needs of future generations.`` We cannot claim to be working toward sustainable development until we can quantitatively assess cumulative impacts on the environment: The two concepts are inextricibally linked in that the elusiveness of cumulative effects likely has the greatest potential of keeping us from achieving sustainability. In this paper, assessment and management frameworks relevant to cumulative impacts are discussed along with recent literature on how to improve such assessments. When possible, examples are given for marine ecosystems.
Date: December 31, 1994
Creator: Hunsaker, C.T.
System: The UNT Digital Library
AGS heavy ion operation with the new booster (open access)

AGS heavy ion operation with the new booster

The AGS Complex has completed its second year of operation with heavy ion beams injected from the Booster for fixed-target research. The booster accepts Au{sup 33+} ions at about 1 MeV/nucleon from the Tandem Van der Graaff and accelerates them to a final energy of about 192 MeV/nucleon. The extracted Au{sup 33+} beam is stripped to Au{sup 77+} before injection into the AGS. Substantial experience has been gained in the areas of injection, acceleration, vacuum, and stripping processes. Deliberately introduced coupling during injection resulted in 50% more beam and a much smaller emittance. A second rf system, for low frequency operation, reduced the vacuum losses and the number of harmonics switches required. Efficiency of stripping of Au{sup 33+} into Au{sup 77+} and various final charge states have been performed as a function of Au{sup 33+} final energy. At the end of the 1993 running period, the maximum intensity achieved in the AGS was about 3 {times} 10{sup 8} nuclei-per-pulse (NPP) of Au{sup 77+} at a kinetic energy of 10.2 GeV/nucleon. In the fall of 1995, a new fast extraction system and beam transport line for RHIC injection will be commissioned. The plan for raising intensity and reducing emittance for RHIC …
Date: August 1, 1994
Creator: Roser, T.
System: The UNT Digital Library
The PROSAIC Laplace and Fourier Transform (open access)

The PROSAIC Laplace and Fourier Transform

Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today`s emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting.
Date: November 1, 1994
Creator: Smith, G. A.
System: The UNT Digital Library