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Focal Length Measurements for the National Ignition Facility Large Lenses

Description: The focal length of the spatial filter and final focus lenses for the National Ignition Facility are measured to < {+-} 0.01% using a combination of master lenses and production-oriented techniques for relative focal length.
Date: January 25, 2002
Creator: Parham, T G; McCarville, T J; Johnson, M A & Kiikka, C
Partner: UNT Libraries Government Documents Department

The Use of Non-Linear Regression Methods for Analysing Sensitivity and Quantal Response Data

Description: A great many special methods for the statistical analysis of sensitivity or quantal response data have been developed during the past century. This paper demonstrates that many of these techniques can be considered in the light of non-linear regression methods which have been made more tolerable in recent years with the prevalence of high-speed computers.
Date: August 25, 1965
Creator: Moore, R H & Zeigler, R K
Partner: UNT Libraries Government Documents Department

Novel Yersinia Pestis Toxin that Resembles Bacillus Anthracis Edema Factor: Study of Activity and Structural Modeling

Description: The goal of this project was to begin both experimental and computational studies of the novel plague toxin to establish its biological properties and create its 3D-model. The project was divided into two parts. (1) Experimental--This part was devoted to determine distribution of the genes encoding novel plague toxin among different isolates of Y.pestis. If the EF-like activity is important for Y.pestis pathogenicity, it is anticipated that all highly virulent strains will contain the toxin genes. Also, they proposed to initiate research to investigate the functionality of the novel Y.pestis toxin that they hypothesize is likely to significantly contribute to the virulence of this dangerous microbe. this research design consisted of amplification, cloning and expression in E.coli the toxin genes followed by affinity purification of the recombinant protein that can be further used for testing of enzymatic activity. (2) Computational--The structural modeling of the putative EF of Y.pestis was based on multiple sequence alignments, secondary structure predictions, and comparison with 3D models of the EF of B. anthracis. The x-ray structure of the last has been recently published [Nature. 2002. 415(Jan):396-402]. The final model was selected after detailed analysis to determine if the structure is consistent with the biological function.
Date: February 5, 2003
Creator: Motin, V; Garcia, E; Barsky, D & Zemla, A
Partner: UNT Libraries Government Documents Department

Production of Biodiesels from Multiple Feedstocks and Properties of Biodiesels and Biodiesel/Diesel Blends: Final Report; Report 1 in a Series of 6

Description: In a project sponsored by the National Renewable Energy Laboratory, the Institute of Gas Technology is conducting an investigation of biodiesels produced from vegetable and animal based feedstocks. This subcontract report presents their findings.
Date: March 1, 2003
Creator: Kinast, J. A.
Partner: UNT Libraries Government Documents Department

Spin-polaron theory of high-{Tc} superconductivity: 2, electronic structure of the CuO{sub 2} planes

Description: After an introductory discussion of electronic structure calculations for the CuO{sub 2} planes in the copper-oxide based high-{Tc} superconductors, the method suggested by Slater for studying antiferromagnetic (AF) metals is described. In this method, as applied here, the chemical unit cell is doubled to form a magnetic unit cell which contains one Cu ion with predominantly up spin and one with predominantly down spin. Down spins are kept off up-spin sites, and conversely, by the introduction of a Hubbard U term. As a result, the band structure obtained is typical of that for a Mott-Hubbard (M-H) or, more generally, a charge transfer insulator. Conductivity in the a-b plane results when holes are introduced into the M-H valence band. The band structure as a function of the parameters in Koster-Slater type calculations is discussed and the Fermi surface is described. A calculation of the delocalization energy for spin-polaron formation is carried out within the context of the band calculations.
Date: June 1, 1993
Creator: Wood, R. F.
Partner: UNT Libraries Government Documents Department

Evolution of Defects in Pu during Isochronal Annealing and Self Irradiation

Description: We report on the evolution of defects in Pu during isochronal annealing and self irradiation using positron annihilation spectroscopy. Positron annihilation spectroscopy is a sensitive probe (part per million level) for atomic-scale defects. The spectroscopic tools available at LLNL allow the determination of size, concentration, and chemical surroundings of defects in aged Pu samples. Positron lifetime analysis was performed on eight samples aged 7 months to 42 years. All samples except the 7-month old sample contained a high concentration of positron trapping centers. The dominant component yielded a lifetime value of {approx}182 ps. In aged samples, a second longer lifetime component was observed that appears to increase in strength with the age of the sample. The observed lifetime values and their relative strengths are shown in figure 1. The top panel corresponds to the lifetime values and the bottom panel corresponds to the intensity of the long lifetime component. Positron lifetime values are determined by the bubble size and He content. When He is added to a bubble, the positron lifetime is shortened due to the increased electron density. When the size of the bubble is known from an independent measurement, the observed positron lifetime values and the associated first principle calculations can be used to estimate the He content of the bubble. Our positron results can be combined with the recent transmission electron microscopy measurements of Schwartz et al to estimate the He content of the bubbles. The short lifetime component corresponds to 2-3 He atoms per vacancy. A 35-year old sample was annealed to 440 C in several steps to examine the temperature stability of the two lifetime features. The isochronal anneals were performed for 30 minutes, increasing the temperature with each subsequent step. This measurement complements a previous annealing study on recast, 7-month old material. The primary ...
Date: February 5, 2003
Creator: Asoka-Kumar, P; Glade, S; Sterne, P A & Howell, R
Partner: UNT Libraries Government Documents Department

Linear collider systems and costs

Description: The purpose of this paper is to examine some of the systems and sub-systems involved in so-called ``conventional`` e{sup +}e{sup {minus}} linear colliders and to study how their design affects the overall cost of these machines. There are presently a total of at least six 500 GeV c. of m. linear collider projects under study in the world. Aside from TESLA (superconducting linac at 1.3 GHz) and CLIC (two-beam accelerator with main linac at 30GHz), the other four proposed e{sup +}e{sup {minus}} linear colliders can be considered ``conventional`` in that their main linacs use the proven technique of driving room temperature accelerator sections with pulsed klystrons and modulators. The centrally distinguishing feature between these projects is their main linac rf frequency: 3 GHz for the DESY machine, 11.424 GHz for the SLAC and JLC machines, and 14 GHz for the VLEPP machine. The other systems, namely the electron and positron sources, preaccelerators, compressors, damping rings and final foci, are fairly similar from project to project. Probably more than 80% of the cost of these linear colliders will be incurred in the two main linacs facing each other and it is therefore in their design and construction that major savings or extra costs may be found.
Date: May 1, 1993
Creator: Loew, G. A.
Partner: UNT Libraries Government Documents Department

A new Krylov-subspace method for symmetric indefinite linear systems

Description: Many important applications involve the solution of large linear systems with symmetric, but indefinite coefficient matrices. For example, such systems arise in incompressible flow computations and as subproblems in optimization algorithms for linear and nonlinear programs. Existing Krylov-subspace iterations for symmetric indefinite systems, such as SYMMLQ and MINRES, require the use of symmetric positive definite preconditioners, which is a rather unnatural restriction when the matrix itself is highly indefinite with both many positive and many negative eigenvalues. In this note, the authors describe a new Krylov-subspace iteration for solving symmetric indefinite linear systems that can be combined with arbitrary symmetric preconditioners. The algorithm can be interpreted as a special case of the quasi-minimal residual method for general non-Hermitian linear systems, and like the latter, it produces iterates defined by a quasi-minimal residual property. The proposed method has the same work and storage requirements per iteration as SYMMLQ or MINRES, however, it usually converges in considerably fewer iterations. Results of numerical experiments are reported.
Date: October 1, 1994
Creator: Freund, R. W. & Nachtigal, N. M.
Partner: UNT Libraries Government Documents Department

A feasibility assessment of magnetic bearings for free-piston Stirling space power converters

Description: This report describes work performed by Mechanical Technology Incorporated (MTI) under NASA Contract NAS3-26061, {open_quotes}A Feasibility Assessment of Magnetic Bearings for Free-Piston Stirling Space Engines.{close_quotes} The work was performed over the period from July 1990 through August 1991. The objective of the effort was to assess the feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery of the type currently being evaluated for possible use in future long-term space missions.
Date: June 1, 1992
Creator: Curwen, P. W.; Rao, D. K. & Wilson, D. S.
Partner: UNT Libraries Government Documents Department

Guide to use the data features of the AT&T 7506, 7507, and 8510T ISDN phones

Description: Integrated Service digital Network, ISDN, technology is an integral component of Sandia National Laboratories telecommunications infrastructure. ISDN is a fully digital telephone service that allows simultaneous voice and data communication from the same telephone instrument. Almost all ISDN phones in use at Sandia/New Mexico and most ISDN phones at Sandia/California have a built-in module for data communication. This user guide describes the use and operation of ISDN data module and services as they are installed at Sandia.
Date: July 1, 1994
Creator: Eldridge, J. M.
Partner: UNT Libraries Government Documents Department

Research on thermophoretic and inertial aspects of ash particle deposition on heat exchanger surfaces in coal-fired equipment. Quarterly report No. 9, September 1, 1988--November 30, 1988

Description: A real-time laser light-reflectivity technique is being used to study simultaneous thermophoretic and inertial influences on the deposition behavior of MgO particles produced via ultrasonic nebulization (submicrometer range). The deposition surface (a concave platinum ribbon) is exposed to a high velocity/temperature jet of alkali sulfate-free combustion products exiting from a seeded (C3{sub 3}H{sub 8}/air) microcombustor (110 cm{sup 3}). The reflectivity data were calibrated against deposition rates obtained from SEM pictures of the target, and were normalized with the nominal particle feed rate, in order to obtain the mass transfer Stanton number, St{sub m}, trends depicted in Figure 1. For the submicron (ca. 0.7{mu}m) particles inertial effects appear to set in at Stokes (Stk) numbers of O(10{sup {minus}2}) (an order of magnitude lower than the ones needed for ``pure`` inertial impaction), affecting significantly the dominant thermophoretic deposition mechanism. A first order (in Stk) theoretical analysis of the problem in which particle inertia is treated as equivalent to ``pressure diffusion,`` cannot explain the observed dependence of the deposition rate on Stk. We are presently formulating a Lagrangian approach, valid for all values of Stk, in order to interpret these data. In addition, a Single Particle Counter (SPC) and Transit Time Velocimeter (TTV), are being developed, to allow more precise measurements of particle feed rates and velocities.
Date: December 1, 1988
Creator: Rosner, D. E.
Partner: UNT Libraries Government Documents Department

Development of a novel and environmentally friendly method for the separation of non-inked and inked cellulose fibers in wastepaper

Description: There is currently no method in existence for the separation of non-inked cellulose fibers from the inked fibers in old newsprint (ONP). Current methods for de-inking involve the pulping of the whole paper in the presence of chemicals (caustic sodium hydroxide, diethylenetriaminepentaacetic acid, sodium silicate, hydrogen peroxide, and a surfactant) followed by washing and flotation operations. The result is a mixture of high- and low-quality de-inked secondary fibers and the production of wastewater that has to be rendered harmless prior to its discharge back to the environment. Water-based inks are a particular problem because of the difficulties in recovering the ink particles after their release from ONP by chemical treatment. Currently, only 15 to 20% of the newsprint market in the USA uses water-based inks. The use of such inks is, however, preferable from an environmental point of view. The work reported here solves several problems: (1) a separation of non-inked from inked cellulose fibers in ONP has been accomplished without the use of de-inking chemicals; (2) the ink is not released to any great extent from the inked fibers; (3) the non-inked fibers contain substantial quantities of long fibers ranging from 1 to 3.5 mm and, as such, are judged to be high-quality secondary fibers that could be recycled without further chemical treatment; and (4) the method is suitable for separating the non-inked and inked fibers in ONP utilizing water- and oil-based inks.
Date: September 1, 1993
Creator: Woodward, J.; Koran, L. J. Jr.; Stephan, L. M.; Wong, K. K. Y. & Saddler, J. H.
Partner: UNT Libraries Government Documents Department

Environmental restoration waste materials co-disposal

Description: Co-disposal of radioactive and hazardous waste is a highly efficient and cost-saving technology. The technology used for final treatment of soil-washing size fractionization operations is being demonstrated on simulated waste. Treated material (wasterock) is used to stabilize and isolate retired underground waste disposal structures or is used to construct landfills or equivalent surface or subsurface structures. Prototype equipment is under development as well as undergoing standardized testing protocols to prequalify treated waste materials. Polymer and hydraulic cement solidification agents are currently used for geotechnical demonstration activities.
Date: September 1, 1993
Creator: Phillips, S. J.; Alexander, R. G.; England, J. L.; Kirdendall, J. R.; Raney, E. A.; Stewart, W. E. et al.
Partner: UNT Libraries Government Documents Department

Quantum Dot Solar Cells: Preprint

Description: Presented at the 2001 NCPV Program Review Meeting: Potential of quantum dot solar cells to increase the maximum attainable thermodynamic conversion efficiency of solar photoconversion to about 66%.
Date: October 1, 2001
Creator: Nozik, A. J.
Partner: UNT Libraries Government Documents Department

Early Site Permit Demonstration Program: Guidelines for determining design basis ground motions. Volume 1

Description: This report develops and applies a methodology for estimating strong earthquake ground motion. The motivation was to develop a much needed tool for use in developing the seismic requirements for structural designs. An earthquake`s ground motion is a function of the earthquake`s magnitude, and the physical properties of the earth through which the seismic waves travel from the earthquake fault to the site of interest. The emphasis of this study is on ground motion estimation in Eastern North America (east of the Rocky Mountains), with particular emphasis on the Eastern United States and southeastern Canada. Eastern North America is a stable continental region, having sparse earthquake activity with rare occurrences of large earthquakes. While large earthquakes are of interest for assessing seismic hazard, little data exists from the region to empirically quantify their effects. Therefore, empirically based approaches that are used for other regions, such as Western North America, are not appropriate for Eastern North America. Moreover, recent advances in science and technology have now made it possible to combine theoretical and empirical methods to develop new procedures and models for estimating ground motion. The focus of the report is on the attributes of ground motion in Eastern North America that are of interest for the design of facilities such as nuclear power plants. Specifically considered are magnitudes M from 5 to 8, distances from 0 to 500 km, and frequencies from 1 to 35 Hz.
Date: March 18, 1993
Partner: UNT Libraries Government Documents Department

High temperature hydrogen sulfide removal with stannic oxide

Description: This contract focuses on the development of sorbents and processes for removal of H{sub 2}S from hot coal gas with the product of sorbent regeneration being elemental sulfur. TDA Research`s process uses a regenerable tin(IV) oxide-based (SnO{sub 2}) sorbent as the first sorbent and zinc ferrite (or zinc titanate) as a second sorbent.
Date: October 1, 1994
Creator: Karpuk, M. E.; Copeland, R. J.; Feinberg, D.; Wickham, D.; Windecker, B. & Yu, J.
Partner: UNT Libraries Government Documents Department

Geologic setting of the New Production Reactor within the Savannah River Site

Description: The geology and hydrology of the reference New Production Reactor (NPR) site at Savannah River Site (SRS) have been summarized using the available information from the NPR site and areas adjacent to the site, particularly the away from reactor spent fuel storage site (AFR site). Lithologic and geophysical logs from wells drilled near the NPR site do not indicate any faults in the upper several hundred feet of the Coastal Plain sediments. However, the Pen Branch Fault is located about 1 mile south of the site and extends into the upper 100 ft of the Coastal Plain sequence. Subsurface voids, resulting from the dissolution of calcareous portions of the sediments, may be present within 200 ft of the surface at the NPR site. The water table is located within 30 to 70 ft of the surface. The NPR site is located on a groundwater divide, and groundwater flow for the shallowest hydraulic zones is predominantly toward local streams. Groundwater flow in deeper Tertiary sediments is north to Upper Three Runs Creek or west to the Savannah River Swamp. Groundwater flow in the Cretaceous sediments is west to the Savannah River.
Date: December 31, 1991
Creator: Price, V.; Fallaw, W. C. & McKinney, J. B.
Partner: UNT Libraries Government Documents Department

[Atomic and electronic structure of metals and alloys: Clean surfaces and chemisorbed molecules]

Description: Ultrapure Tb was further purified and surface cleaning procedures developed for basal plane and (11{bar 2}0) surface of Tb. Structure of both surfaces was found to be relaxed: (0001) is contracted by 3.9% in the first and expanded by 1.4% in second interlayer spacing; (11{bar 2}0) is contracted by 3.3% in first layer and shows a change in registry. Thin films of Gd, Tb, Dy, Ho, and Er were grown on W{l_brace}110{r_brace} substrate in ultrahigh vacuum. Studies have been carried out on epitaxial systems involving Cu, Fe and Mn on Fe and Pt, Cu, and Pd substrates, respectively; new metastable crystalline phases have been found. Studies of possible ferromagnetism in 4d elements (Rh, Ru) and relativistic effects in electron band structure of Cu{l_brace}111{r_brace} have been completed and published. Plans for the following year are given.
Date: December 31, 1993
Partner: UNT Libraries Government Documents Department

Final Report - Effect of Magnetic Configuration on Spheromak Performances, FY2000 - FY2001, Tracking No.00-SI-008

Description: This is the final report on LDRD SI-funded research to determine the Effect of Magnetic Field Configurations on Spheromak Performance for the years FY2000-FY2001, during which a new set of bias magnetic field coils was used to change the vacuum magnetic field configuration of the SSPX spheromak at LLNL. The USDOE Office of Fusion Energy Science funded the routine operation of the SSPX facility during FY00 and FY01. A photo of the SSPX facility as it appeared in mid-FY01, appears in this report. The main distinctive feature of the spheromak is that currents in the plasma itself produce the confining toroidal magnetic field, rather than a complex set of external coils. The Sustained Spheromak Physics Experiment (SSPX) device was designed and built study how well the spheromak can contain plasma energy while dynamo processes in the plasma maintain the confining magnetic fields. The spheromak potentially offers advantages over other fusion reactor concepts because it is compact, has no field coils linking the vacuum vessel, and can be operated in a steady state with voltage applied to external electrodes. It is predicted that the ability of the SSPX to contain the plasma thermal energy will increase with increasing plasma electron temperature; that is, the hotter it is, the better it will work. Our near-term goal for the SSPX facility is to determine which of several magnetic field configurations works best to produce hot, well-confined spheromak plasmas. We also want to verify the predicted inverse relation between plasma temperature and heat loss, and to use these results to design an even higher-temperature follow-on experiment that will push closer to fusion conditions. New features of the SSPX spheromak include a large-radius coaxial plasma injector to improve efficiency, a conformal flux conserver to minimize open field lines around the plasma, a divertor to aid ...
Date: February 6, 2002
Creator: Hill, D N; Hooper, E B; McLean, H S; Stallard, B W; Woodruff, S & Wood, R D
Partner: UNT Libraries Government Documents Department

FY 1993 progress report on the ANS thermal-hydraulic test loop operation and results

Description: The Thermal-Hydraulic Test Loop (THTL) is an experimental facility constructed to support the development of the Advanced Neutron Source Reactor (ANSR) at Oak Ridge National Laboratory (ORNL). Highly subcooled heavy-water coolant flows vertically upward at a very high mass flux of almost 27 MG/m{sup 2}-s. In a parallel fuel plate configuration as in the ANSR, the flow is subject to a potential excursive static-flow instability that can very rapidly lead to flow starvation and departure from nucleate boiling (DNB) in the ``hot channel``. The current correlations and experimental data bases for flow excursion (FE) and critical heat flux (CHF) seldom evaluate the specific combination of ANSR operating parameters. The THTL facility was designed and built to provide known thermal-hydraulic (T/H) conditions for a simulated full-length coolant subchannel of the ANS reactor core, thus facilitating experimental determination of FE and CHF thermal limits under expected ANSR T/H conditions. A series of FE tests with water flowing vertically upward was completed over a nominal heat flux range of 6 to 17 MW/m{sup 2}, a mass flux range of 8 to 28 Mg/m{sup 2}-s, an exit pressure range of 1.4 to 2.1 MPa, and an inlet temperature range of 40 to 50 C. FE experiments were also conducted using as ``soft`` a system as possible to secure a true FE phenomena (actual secondary burnout). True DNB experiments under similar conditions were also conducted. To the author`s knowledge, no other FE data have been reported in the literature to date that dover such a combination of conditions of high mass flux, high heat flux, and moderately high pressure.
Date: July 1, 1994
Creator: Siman-Tov, M.; Felde, D. K. & Farquharson, G.
Partner: UNT Libraries Government Documents Department

Heterogeneous catalytic process for alcohol fuels from syngas. Second quarterly technical progress report, April--June 1992

Description: The principal objectives of this project are to discover and evaluate novel heterogeneous catalysts for conversion of syngas to oxygenates having use as fuel enhancers, to explore novel reactor and process concepts applicable in this process, and to develop the best total process for converting syngas to liquid fuels. The project is being pursued as two concurrent tasks. Task I involves catalyst research and development and is being largely conducted by catalyst chemists and analytical specialists. Task 2 is largely an engineering activity, and includes process conceptualization and economics and bench-scale process evaluation of systems developed in Task 1. The current goal of the catalyst development program is to increase selectivities to oxygenates to greater than 90% with methanol making up less than 70% of the oxygenates, increase rates to 20 lb/ft{sup 3}/hr, and have conversions of greater than 20%. Earlier work in this organization has shown that a potassium-modified Zn-Or-Mn-0 based catalyst system had alcohol selectivities as high as 70-80 wt %, but the overall alcohol yield was only 11 lb/ft{sup 3}/hr. The effects of the precipitation pH on surface area, porosity, and thermal characteristics of the mixed metal oxide component were examined. A designed experiment showed that the precipitation pH was an important factor influencing the BET surface area, and the calcination temperature had a negative effect on the surface area as expected. The optimal surface area for a given calcination temperature would be achieved at a pH of around 10.2. Other interesting results from the models were that calcination time did not affect any of the physical properties measured and only calcination temperature affected the mean pore diameter of the solid.
Date: December 31, 1992
Partner: UNT Libraries Government Documents Department