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Advances in orbit drift correction in the advanced photon source storage ring

Description: The Advanced Photon Source storage ring is required to provide X-ray beams of high positional stability, specified as 17 {mu}m rms in the horizontal plane and 4.4 {mu}m rms in the vertical plane. The author reports on the difficult task of stabilizing the slow drift component of the orbit motion down to a few microns rms using workstation-based orbit correction. There are two aspects to consider separately the correction algorithm and the configuration of the beam position monitors (BPMs) and correctors. Three notable features of the correction algorithm are: low-pass digital filtering of BPM readbacks; {open_quotes}despiking{close_quotes} of the filtered orbit to desensitize the orbit correction to spurious BPM readbacks without having to change the correction matrix; and BPM intensity-dependent offset compensation. The BPM/corrector configuration includes all of the working BPMs but only a small set of correctors distributed around the ring. Thus only those orbit modes that are most likely to be representative of real beam drift are handled by the correction algorithm.
Date: June 1, 1997
Creator: Emery, L. & Borland, M.

Advances in Photovoltaics at NREL

Description: This paper discusses the critical strategic research and development issues in the development of next-generation photovoltaic technologies, emphasizing thin-film technologies that are believed to ultimately lead to lower production costs. The critical research and development issues for each technology are identified. An attempt is made to identify the strengths and weaknesses of the different technologies, and to identify opportunities for fundamental research activities suited to advance the introduction of improved photovoltaic modules.
Date: September 9, 1999
Creator: von Roedern, B.

Advances in processing of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductors.

Description: Advances in the processing and fabrication of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) high-T{sub c} superconductors by the powder-in-tube technique continue to bring this material closer to commercial applications. Enhancement of the transport critical current density (J{sub c}) of Ag-sheathed Bi-2223 tapes was achieved by increasing the packing density of the precursor powder, improving mechanical deformation, and adjusting the cooling rate. Long lengths (>150 m) of multifilamentary Bi-2223 tapes have been fabricated and carry critical currents (I{sub c}) of >50 A (J{sub c} {approx} 25 kA/cm{sup 2}) at 77 K in self-field. A 1260-m-long tape carried an I{sub c} of 18 A (J{sub c} {approx} 12 kA/cm{sup 2}) from end-to-end. Several prototype coils have been assembled from these long-length tapes. Recent progress in the fabrication of Bi-2223 tapes is presented in this paper.
Date: March 5, 1998
Creator: Balachandran, U.; Eror, N. G.; Haldar, P. & Lelovic, M.

Advances in PSII Deposited Diamond-Like Carbon Coatings for Use as a Barrier to Corrosion

Description: Plasma source ion implantation (PSII) is a non line of sight process for implanting complex shaped targets without the need for complex fixturing. The breakdown initiation of materials coated with diamond-like carbon (DLC) produced by PSII occurs at defects in the DLC which expose the underlying material. To summarize these findings, a galvanic couple is established between the coating and exposed material at the base of the defect. Pitting and oxidation of the base and metal leads to the development of mechanical stress in the coating and eventually spallation of the coating. This paper presents our current progress in attempting to mitigate the breakdown of these coatings by implanting the parent material prior to coating with DLC. Ideally one would like to implant the parent material with chromium or molybdenum which are known to improve corrosion resistance, however, the necessary organometallics needed to implant these materials with PSII are not yet available. Here we report on the effects of carbon, nitrogen, and boron implantation on the susceptibility of PSII-DLC coated mild steel to breakdown.
Date: October 1, 1998
Creator: Lillard, R.S.; Butt, D.P.; Baker, N.P.; Walter, K.C. & Nastasi, M.

Advances in the chemical conversion of energetic materials to higher value products

Description: The objective of this program is to develop novel, innovative solutions for the disposal of surplus explosives resulting from the demilitarization of nuclear and conventional munitions by DOE and DoD. Studies related to the conversion of TNT and Explosive D to potentially useful materials are described. The paper describes the feasibility of conversion of TNT to TATB; conversion of TNT to 3,5-diamino-2,4,6-trinitrotoluene (DATNT); conversion of TNT to tolylene 2,4-diisocyanate (TDI) and nitrotolylene and diisocyanate (NTDI); chelating resins derived from trinitroarenes.
Date: January 24, 1995
Creator: Mitchell, A.R.; Pagoria, P.F. & Sanner, R.D.

Advances in the determination of quark masses

Description: Significant progress has been made in the determination of the light quark masses, using both lattice QCD and sum rule methods, in the last year. The authors discuss the different methods and review the status of current results. Finally, they review the calculation of bottom and charm masses.
Date: March 1, 1998
Creator: Bhattacharya, T. & Gupta, R.

Advances in the development of FTIR continuous emission monitor for incinerators

Description: The integrated, transportable FTIR-CEM was successfully tested from September 13 to 21, 1994, at the K-25 TSCA incinerator, in Oak Ridge, Tennessee. the field test followed the requirements of a procedure, which was submitted to the EPA for approval. The test results met all the requirement listed in the proposed procedure. Extensive spiking tests were conducted during the field test. The FTIR-CEM quantitatively detected all spiked analytes measured the stack emission variation during the ignition period of the incinerator. For the stack samples obtained under normal incineration conditions, no target analytes were detected at concentrations above the instrument detection limits, except for methane, which was occasionally detected at 4-5 ppM. Future work will involve making the master control software more robust to use, improving the accuracy of the analytical methods, and testing system effectiveness for various emission sources. A commercial version of the system is currently being developed.
Date: June 1, 1995
Creator: Mao, Zhouxiong; Demirgian, J.C. & Hwang, E.

Advances in the operation of the DIII-D neutral beam computer systems

Description: The DIII-D neutral beam system routinely provides up to 20 MW of deuterium neutral beam heating in support of experiments on the DIII-D tokamak, and is a critical part of the DIII-D physics experimental program. The four computer systems previously used to control neutral beam operation and data acquisition were designed and implemented in the late 1970`s and used on DIII and DIII-D from 1981--1996. By comparison to modern standards, they had become expensive to maintain, slow and cumbersome, making it difficult to implement improvements. Most critical of all, they were not networked computers. During the 1997 experimental campaign, these systems were replaced with new Unix compliant hardware and, for the most part, commercially available software. This paper describes operational experience with the new neutral beam computer systems, and new advances made possible by using features not previously available. These include retention and access to historical data, an asynchronously fired ``rules`` base, and a relatively straightforward programming interface. Methods and principles for extending the availability of data beyond the scope of the operator consoles will be discussed.
Date: February 1, 1998
Creator: Phillips, J.C.; Busath, J.L.; Penaflor, B.G.; Piglowski, D.; Kellman, D.H.; Chiu, H.K. et al.

Advances in the reduction and compensation of film stress in high-reflectance multilayer coatings for extreme ultraviolet lithography applications

Description: Due to the stringent surface figure requirements for the multilayer-coated optics in an extreme ultraviolet (EUV) projection lithography system, it is desirable to minimize deformation due to the multilayer film stress. However, the stress must be reduced or compensated without reducing EUV reflectivity, since the reflectivity has a strong impact on the throughput of a EUV lithography tool. In this work we identify and evaluate several leading techniques for stress reduction and compensation as applied to Mo/Si and Mo/Be multilayer films. The measured film stress for Mo/Si films with EUV reflectances near 67.4% at 13.4 nm is approximately - 420 MPa (compressive), while it is approximately +330 MPa (tensile) for Mo/Be films with EUV reflectances near 69.4% at 11.4 nm. Varying the Mo-to-Si ratio can be used to reduce the stress to near zero levels, but at a large loss in EUV reflectance (> 20%). The technique of varying the base pressure (impurity level) yielded a 10% decrease in stress with a 2% decrease in reflectance for our multilayers. Post-deposition annealing was performed and it was observed that while the cost in reflectance is relatively high (3.5%) to bring the stress to near zero levels (i.e., reduce by 1 00%), the stress can be reduced by 75% with only a 1.3% drop in reflectivity at annealing temperatures near 200{degrees}C. A study of annealing during Mo/Si deposition was also performed; however, no practical advantage was observed by heating during deposition. A new non-thermal (athermal) buffer-layer technique was developed to compensate for the effects of stress. Using this technique with amorphous silicon and Mo/Be buffer-layers it was possible to obtain Mo/Be and Mo/Si multilayer films with a near zero net film stress and less than a 1% loss in reflectivity. For example a Mo/Be film with 68.7% reflectivity at 11.4 nm and ...
Date: February 20, 1998
Creator: Mirkarimi, P.B., LLNL

Advances in the simulation of toroidal gyro Landau fluid model turbulence

Description: The gyro-Landau fluid (GLF) model equations for toroidal geometry have been recently applied to the study ion temperature gradient (ITG) mode turbulence using the 3D nonlinear ballooning mode representation (BMR). The present paper extends this work by treating some unresolved issues conceming ITG turbulence with adiabatic electrons. Although eddies are highly elongated in the radial direction long time radial correlation lengths are short and comparable to poloidal lengths. Although transport at vanishing shear is not particularly large, transport at reverse global shear, is significantly less. Electrostatic transport at moderate shear is not much effected by inclusion of local shear and average favorable curvature. Transport is suppressed when critical E{times}B rotational shear is comparable to the maximum linear growth rate with only a weak dependence on magnetic shear. Self consistent turbulent transport of toroidal momentum can result in a transport bifurcation at suffciently large r/(Rq). However the main thrust of the new formulation in the paper deals with advances in the development of finite beta GLF models with trapped electron and BMR numerical methods for treating the fast parallel field motion of the untrapped electrons.
Date: December 1994
Creator: Waltz, R. E.; Kerbel, G. D.; Milovich, J. & Hammett, G. W.

Advances in the TOUGH2 family of general-purpose reservoir simulators

Description: TOUGH2 is a general-purpose fluid and heat flow simulators, with applications in geothermal reservoir engineering, nuclear waste disposal, and environmental contamination problems. This report summarizes recent developments which enhance the usability of the code, and provide a more accurate and comprehensive description of reservoir processes.
Date: April 1, 1996
Creator: Pruess, K.; Finsterle, S.; Moridis, G.; Oldenburg, C.; Antunez, E. & Wu, Y.S.

Advances in the use of tomographic inspection techniques for non-destructive analysis of geometric conductor position and correlation with magnetic cross-section modeling

Description: Industrial Computerized Tomography has been applied to magnet components in various stages of the manufacturing process. These Computerized Tomographic images can be analyzed to infer detailed dimensional information about magnet component positions (conductor, wedges, collars, etc.) throughout the magnet manufacturing process (cable winding, collaring, yoked/skinned). An analysis technique will be presented and measurement accuracies will be discussed.
Date: May 1, 1993
Creator: Bein, D.; Snitchler, G.; Rabaey, G.F.; Bolger, J.; Crane, R. Morgan, I.L. & Vinson, M.

Advances in tubular solid oxide fuel cell technology

Description: This document provides the functional design criteria for an addition to the 222-S facility. This project will provide space for manipulator repair, equipment and manipulator decontamination and laundry storage. The manipulator repair and storage area will provide for storage of 20 manipulators, an area for receiving potentially contaminated manipulators and an area for the repair of manipulators. The decontamination area will be capable of decontamination of manipulators and shipping casks, pigs, T-handle carriers and other shipping containers. The laundry storage area will provide space for potentially contaminated and clean laundry.
Date: March 1, 1995
Creator: Singhal, S.C.

Advances in welding science and technology

Description: Over the years, welding has been more of an art than a science, but in the last few decades major advances have taken place in welding science and technology. With the development of new methodologies at the crossroads of basic and applied sciences, enormous opportunities and potential exist to develop a science-based design of composition, structure, and properties of welds with intelligent control and automation of the welding processes. In the last several decades, welding has evolved as an interdisciplinary activity requiring synthesis of knowledge from various disciplines and incorporating the most advanced tools of various basic applied sciences. A series of international conferences and other publications have covered the issues, current trends and directions in welding science and technology. In the last few decades, major progress has been made in (i) understanding physical processes in welding, (ii) characterization of microstructure and properties, and (iii) intelligent control and automation of welding. This paper describes some of these developments.
Date: December 31, 1995
Creator: David, S.A.; Babu, S.S. & Vitek, J.M.

Advances in x-ray computed microtomography at the NSLS

Description: The X-Ray Computed Microtomography workstation at beamline X27A at the NSLS has been utilized by scientists from a broad range of disciplines from industrial materials processing to environmental science. The most recent applications are presented here as well as a description of the facility that has evolved to accommodate a wide variety of materials and sample sizes. One of the most exciting new developments reported here resulted from a pursuit of faster reconstruction techniques. A Fast Filtered Back Transform (FFBT) reconstruction program has been developed and implemented, that is based on a refinement of the gridding algorithm first developed for use with radio astronomical data. This program has reduced the reconstruction time to 8.5 sec for a 929 x 929 pixel{sup 2} slice on an R10,000 CPU, more than 8x reduction compared with the Filtered Back-Projection method.
Date: August 1, 1998
Creator: Dowd, B.A.; Andrews, A.B.; Marr, R.B.; Siddons, D.P.; Jones, K.W. & Peskin, A.M.

ADVANCES IN X-RAY COMPUTED MICROTOMOGRAPHY AT THE NSLS.

Description: The X-Ray Computed Microtomography workstation at beamline X27A at the NSLS has been utilized by scientists from a broad range of disciplines from industrial materials processing to environmental science. The most recent applications are presented here as well as a description of the facility that has evolved to accommodate a wide variety of materials and sample sizes. One of the most exciting new developments reported here resulted from a pursuit of faster reconstruction techniques. A Fast Filtered Back Transform (FFBT) reconstruction program has been developed and implemented, that is based on a refinement of the ''gridding'' algorithm first developed for use with radio astronomical data. This program has reduced the reconstruction time to 8.5 sec for a 929 x 929 pixel{sup 2} slice on an R10,000 CPU, more than 8x reduction compared with the Filtered Back-Projection method.
Date: August 7, 1998
Creator: DOWD,B.A.

Advancing Design-for-Assembly: The Next Generation in Assembly Planning

Description: At the 1995 IEEE Symposium on Assembly and Task Planning, Sandia National Laboratories introduced the Archimedes 2 Software Tool [2]. The system was described as a second-generation assembly planning system that allowed preliminmy application of awembly planning for industry, while solidly supporting further research in planning techniques. Sandia has worked closely with indust~ and academia over the last four years. The results of these working relationships have bridged a gap for the next generation in assembly planning. Zke goal of this paper is to share Sandia 's technological advancements in assembly planning over the last four years and the impact these advancements have made on the manufacturing communip.
Date: December 9, 1998
Creator: Calton, T.L.

Advancing lighting and daylighting simulation: The transition from analysis to design aid tools

Description: This paper explores three significant software development requirements for making the transition from stand-alone lighting simulation/analysis tools to simulation-based design aid tools. These requirements include specialized lighting simulation engines, facilitated methods for creating detailed simulatable building descriptions, an automated techniques for providing lighting design guidance. Initial computer implementations meant to address each of these requirements are discussed to further elaborate these requirements and to illustrate work-in-progress.
Date: May 1, 1995
Creator: Hitchcock, R.J.

Advancing manufacturing through computational chemistry

Description: The capabilities of nanotechnology and computational chemistry are reaching a point of convergence. New computer hardware and novel computational methods have created opportunities to test proposed nanometer-scale devices, investigate molecular manufacturing and model and predict properties of new materials. Experimental methods are also beginning to provide new capabilities that make the possibility of manufacturing various devices with atomic precision tangible. In this paper, we will discuss some of the novel computational methods we have used in molecular dynamics simulations of polymer processes, neural network predictions of new materials, and simulations of proposed nano-bearings and fluid dynamics in nano- sized devices.
Date: December 31, 1995
Creator: Noid, D.W.; Sumpter, B.G. & Tuzun, R.E.

Advancing the Technology Base for High Temperature Hydrogen Membranes

Description: High purity hydrogen is a critical component for at least two major industrial processes: 1) the refining of conventional steels and raw pig iron into low carbon steels and high purity iron used for high performance magnets in motors, generators, alternators, transformers, and etc.; and 2) refining metallurgical grade silicon to the high- purity, polycrystalline silicon used in fabricating single crystal silicon wafers for semiconductor manufacturing. In the process of producing low carbon iron products, CO and CO2 impurities prevent efficient removal of the carbon already in the raw iron. In the refining of metallurgical grade silicon, the presence of any impurity above the part-per- million level prevents the ultimate fabrication of the large scale single crystals that are essential to the semiconductor device. In a lesser magnitude role, high quality hydrogen is used in a variety of other processes, including specialty metals refining (e.g., iridium, osmium, palladium, platinum, and ruthenium) and R{ampersand}D in areas such as organic synthesis and development of certain types of fuel cells. In all of these applications, a high-temperature hydrogen membrane can provide a method for achieving a very high purity level of hydrogen in a manner that is more economical and/or more rugged than existing techniques.
Date: 1997
Creator: Dye, Robert C. & Moss, Thomas S.

Advancing the technology base for high-temperature membranes

Description: This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project addresses the major issues confronting the implementation of high-temperature membranes for separations and catalysis. We are pursuing high-temperature membrane systems that can have a large impact for DOE and be industrially relevant. A major obstacle for increased use of membranes is that most applications require the membrane material to withstand temperatures above those acceptable for polymer-based systems. Advances made by this project have helped industry and DOE move toward high-temperature membrane applications to improve overall energy efficiency.
Date: October 1, 1997
Creator: Dye, R.C.; Birdsell, S.A. & Snow, R.C.