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  Partner: UNT Libraries Government Documents Department
 Decade: 1990-1999
Advanced worker protection system. Topical report, Phase I
The Department of Energy (DOE) is in the process of defining the magnitude and diversity of Decontamination and Decommissioning (D&D) obligations at its numerous sites. The DOE believes that existing technologies are inadequate to solve many challenging problems such as how to decontaminate structures and equipment cost effectively, what to do with materials and wastes generated, and how to adequately protect workers and the environment. Preliminary estimates show a tremendous need for effective use of resources over a relatively long period (over 30 years). Several technologies are being investigated which can potentially reduce D&D costs while providing appropriate protection to DOE workers. The DOE recognizes that traditional methods used by the EPA in hazardous waste site clean up activities are insufficient to provide the needed protection and worker productivity demanded by DOE D&D programs. As a consequence, new clothing and equipment which can adequately protect workers while providing increases in worker productivity are being sought for implementation at DOE sites. This project will result in the development of an Advanced Worker Protection System (AWPS). The AWPS will be built around a life support backpack that uses liquid air to provide cooling as well as breathing gas to the worker. The backpack will be combined with advanced protective garments, advanced liquid cooling garment, respirator, communications, and support equipment to provide improved worker protection, simplified system, maintenance, and dramatically improve worker productivity through longer duration work cycles. digital.library.unt.edu/ark:/67531/metadc665335/
Advanced zinc phosphate conversion coatings. Final report, June 1996--December 1996
A SERDP-sponsored program aims at developing environmentally benign zinc phosphate conversion coatings and their process technologies for the electrogalvanized steel (EGS). We succeeded in formulating an environmentally acceptable phosphate solution without Co- and Ni-related additives, and also in replacing a hexavalent Cr acid sealant applied over the zinc phosphate (Zh-Ph) layers with a water-based polysiloxane sealers. The specific advantages of the newly developed Zn-Ph coatings were as follows: (1) there was rapid growth of uniform, dense embryonic Zn-Ph crystals on the EGS surfaces due to the creation of short-circuited cells with Mn acting as the cathode and the galvanized (zinc) coatings as the anode, (2) an excellent protection layer against corrosion was formed, extending the service life of zinc layers as galvanic sacrifice barriers, and (3) adhesion to the electro-deposited polymeric primer coating was improved because of the interaction between the siloxane sealer and primer. A full-scale demonstration to evaluate the reproducibility of this new coating technology on mini-sized automotive door panels made from EGS was carried out in collaboration with the Palnut Company (as industrial coating applicator) in New Jersey. All of the 150 mini-door panels were successfully coated with Zn-Ph. digital.library.unt.edu/ark:/67531/metadc686239/
Advancements in low NOx tangential firing systems
The most cost effective method of reducing nitrogen oxide emissions when burning fossil fuels, such as coal, is through in-furnace NOx reduction processes. ABB Combustion Engineering, Inc. (ABB CE), through its ABB Power Plant Laboratories has been involved in the development of such low NOx pulverized coal firing systems for many years. This development effort is most recently demonstrated through ABB CE`s involvement with the U.S. Department of Energy`s (DOE) {open_quotes}Engineering Development of Advanced Coal Fired Low-Emission Boiler Systems{close_quotes} (LEBS) project. The goal of the DOE LEBS project is to use {open_quotes}near term{close_quotes} technologies to produce a commercially viable, low emissions boiler. This paper addresses one of the key technologies within this project, the NOx control subsystem. The foundation for the work undertaken at ABB CE is the TFS 2000{trademark} firing system, which is currently offered on a commercial basis. This system encompasses sub-stoichiometric combustion in the main firing zone for reduced NOx formation. Potential enhancements to this firing system focus on optimizing the introduction of the air and fuel within the primary windbox to provide additional horizontal and vertical staging. As is the case with all in-furnace NOx control processes, it is necessary to operate the system in a manner which does not decrease NOx at the expense of reduced combustion efficiency. digital.library.unt.edu/ark:/67531/metadc681831/
Advances in 3D electromagnetic finite element modeling
Numerous advances in electromagnetic finite element analysis (FEA) have been made in recent years. The maturity of frequency domain and eigenmode calculations, and the growth of time domain applications is briefly reviewed. A high accuracy 3D electromagnetic finite element field solver employing quadratic hexahedral elements and quadratic mixed-order one-form basis functions will also be described. The solver is based on an object-oriented C++ class library. Test cases demonstrate that frequency errors less than 10 ppm can be achieved using modest workstations, and that the solutions have no contamination from spurious modes. The role of differential geometry and geometrical physics in finite element analysis is also discussed. digital.library.unt.edu/ark:/67531/metadc692761/
Advances in Ammonia Removal from Hot Coal Gas
Nitrogen occurs in coal in the form of tightly bound organic ring compounds, typically at levels of 1 to 2 wt%. During coal gasification, this fuel bound nitrogen is released principally as ammonia (NH{sub 3}). When hot coal gas is used to generate electricity in integrated gasification combined cycle (IGCC) power plants, NH{sub 3} is converted to nitrogen oxides (NO{sub x}) which are difficult to remove and are highly undesirable as atmospheric pollutants. Similarly, while the efficiency of integrated gasification molten carbonate fuel cell (IGFC) power plants is not affected by NH{sub 3}, NO{sub x} is generated during combustion of the anode exhaust gas. Thus NH{sub 3} must be removed from hot coal gas before it can be burned in a turbine or fuel cell. The objective of this study is to develop a successful combination of an NH{sub 3} decomposition catalyst with a zinc-based mixed-metal oxide sorbent so that the sorbent-catalyst activity remains stable for NH{sub 3} decomposition in addition to H{sub 2}S removal under cycle sulfidation-regeneration conditions in the temperature range of 500 to 750{degrees}C. digital.library.unt.edu/ark:/67531/metadc686119/
Advances in associated-particle sealed-tube neutron probe diagnostics for substance detection
The development and investigation of a small associated-particle sealed-tube neutron generator (APSTNG) shows potential to allow the associated-particle diagnostic method to be moved out of the laboratory into field applications. The APSTNG interrogates the inspected object with 14-MeV neutrons generated from the deuterium-tritium reaction and detects the alpha-particle associated with each neutron inside a cone encompassing the region of interest. Gamma-ray spectra of resulting neutron reactions identify many nuclides. Flight-times determined from detection times of the gamma-rays and alpha-particles can yield a separate coarse tomographic image of each identified nuclide, from a single orientation. Chemical substances are identified by comparing relative spectral line intensities with ratios of elements in reference compounds. The high-energy neutrons and gamma-rays penetrate large objects and dense materials. Generally no collimators or radiation shielding are needed. Proof-of-concept laboratory experiments have been successfully performed for simulated nuclear, chemical warfare, and conventional munitions. Most recently, inspection applications have been investigated for radioactive waste characterization, presence of cocaine in propane tanks, and uranium and plutonium smuggling. Based on lessons learned with the present APSTNG system, an advanced APSTNG tube (along with improved high voltage supply and control units) is being designed and fabricated that will be transportable and rugged, yield a substantial neutron output increase, and provide sufficiently improved lifetime to allow operation at more than an order of magnitude increase in neutron flux. digital.library.unt.edu/ark:/67531/metadc794019/
Advances in atmospheric chemistry modeling: the LLNL impact tropospheric/stratospheric chemistry model
We present a unique modeling capability to understand the global distribution of trace gases and aerosols throughout both the troposphere and stratosphere. It includes the ability to simulate tropospheric chemistry that occurs both in the gas phase as well as on the surfaces of solid particles. We have used this capability to analyze observations from particular flight campaigns as well as averaged observed data. Results show the model to accurately simulate the complex chemistry occurring near the tropopause and throughout the troposphere and stratosphere. digital.library.unt.edu/ark:/67531/metadc622182/
Advances in beam physics and technology: Colliders of the future
Beams may be viewed as directed and focussed flow of energy and information, carried by particles and electromagnetic radiation fields (ie, photons). Often, they interact with each other (eg, in high energy colliders) or with other forms of matter (eg, in fixed targets, sychrotron radiation, neutron scattering, laser chemistry/physics, medical therapy, etc.). The whole art and science of beams revolve around the fundamental quest for, and ultimate implementation of, mechanisms of production, storage, control and observation of beams -- always directed towards studies of the basic structures and processes of the natural world and various practical applications. Tremendous progress has been made in all aspects of beam physics and technology in the last decades -- nonlinear dynamics, superconducting magnets and rf cavities, beam instrumentation and control, novel concepts and collider praradigms, to name a few. We illustrate this progress with a few examples and remark on the emergence of new collider scenarios where some of these progress might come to use -- the Gamma-Gamma Collider, the Muon Collider, laser acceleration, etc. We close with an outline of future oppotunities and outlook. digital.library.unt.edu/ark:/67531/metadc670203/
Advances in beryllium powder consolidation simulation
A fuzzy logic based multiobjective genetic algorithm (GA) is introduced and the algorithm is used to optimize micromechanical densification modeling parameters for warm isopressed beryllium powder, HIPed copper powder and CIPed/sintered and HIPed tantalum powder. In addition to optimizing the main model parameters using the experimental data points as objective functions, the GA provides a quantitative measure of the sensitivity of the model to each parameter, estimates the mean particle size of the powder, and determines the smoothing factors for the transition between stage 1 and stage 2 densification. While the GA does not provide a sensitivity analysis in the strictest sense, and is highly stochastic in nature, this method is reliable and reproducible in optimizing parameters given any size data set and determining the impact on the model of slight variations in each parameter. digital.library.unt.edu/ark:/67531/metadc674280/
Advances in crosswell electromagnetics steel cased boreholes
The Crosswell electromagnetic (EM) induction technique ideally measures the resistivity distribution between boreholes which may often be cased with carbon steel. Quantification of the effect of such steel casing on the induced field is the most significant limitation of the technique. Recent data acquired at a site in Richmond, California quantify the effect of steel casing on induction measurements and demonstrate this effect to be separable. This unique site contains adjacent steel and plastic wells in which frequency soundings demonstrate low spectrum (1.0 - 50 Hz) measurements an effective means of isolating the casing response from, the formation response. It is also shown that the steel casing effect on the induction coil is highly localized, and limited to less than 0.30 meters above and below the coil. digital.library.unt.edu/ark:/67531/metadc627976/
Advances in DC photocathode electron guns
At Jefferson Lab, a DC photoemission gun using GaAs and GaAs-like cathodes provides a source of polarized electrons for the main accelerator. The gun is required to produce high average current with long operational lifetimes and high system throughout. Recent work has shown that careful control of the parameters affecting cathode lifetime lead to dramatic improvements in source operation. These conditions include vacuum and the related effect of ion backbombardment, and precise control of all of the electrons emitted from the cathode. In this paper, the authors will review recent results and discuss implications for future photocathode guns. digital.library.unt.edu/ark:/67531/metadc703754/
Advances in defect characterizations of semiconductors using positrons
Positron Annihilation Spectroscopy (PAS) is a sensitive probe for studying the electronic structure of defects in solids. The authors summarize recent developments in defect characterization of semiconductors using depth-resolved PAS. The progress achieved in extending the capabilities of the PAS method is also described. digital.library.unt.edu/ark:/67531/metadc681101/
Advances in excimer laser processing of materials
The use of pulsed excimer lasers to surface processing of materials hinges on an understanding of the nature of the interaction between the laser energy and the material. The application of this understanding of the laser materials interaction to surface modification must also recognize the existence of thermodynamic driving forces and kinetic limitations in light of the short duration of a single pulse event. For species that have higher solubility in the liquid than in the solid phase, segregation by ``zone refinement`` from multiple passes by a solidification front to the surface results in surface enrichment of those species. The most obvious applications for surface processing occur where the bulk properties of a component are not commensurate with the needed surface properties. Improvements in surface mechanical properties have been observed in a number of metal and ceramic alloys. In the microelectronics industry, apart from micromachining or material removal applications, for which excimers are indeed well suited, the same features of the laser-materials interaction that are used to modify the mechanical or electrochemical properties of a surface can be used to advantage. Further advances, such as those demonstrated in microelectronics, await application-specific developments. 22 refs., 1 fig. digital.library.unt.edu/ark:/67531/metadc666065/
Advances in fabrication of Ag-clad Bi-2223 superconductors.
Powder-in-tube (PIT) processing was used to fabricate multifilamentary Ag-clad Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} (Bi-2223) superconductors for various electric power applications. Enhancements in the transport current properties of long lengths of multifilament tapes were achieved by increasing the packing density of the precursor powder, improving the mechanical deformation, and adjusting the cooling rate. The dependence of the critical current density on magnetic field and temperature for the optimally processed tapes was measured. J{sub c} was greater than 10{sup 4} (A/cm{sup 2}) at 20 K for magnetic field up to 3 T and parallel to the c-axis which is of interest for use in refrigerator coded magnets. An attempt was made to combine the good alignment of Bi-2223 grains in Ag-sheathed superconducting tapes to obtain high J{sub c} values at high temperature and low field, and good intrinsic pinning of YBa{sub 2}Cu{sub 3}O{sub 7{minus}d} (Y-123) thin film to maintain high J{sub c} values in high fields. A new composite multifilament tape was fabricated such that the central part contained Bi-2223 filaments, with the primary function of conducting the transport current. The central Bi-2223 filaments were surrounded by Y-123 thin film to shield the applied magnetic field and protect the Bi-2223 filaments. The J{sub c} values of the composite tape were better than those of an uncoated tape. In the case of 77 K applications, an I{sub c} of about 60 A was obtained in a 150 m long tape and zero applied magnetic field. In-situ strain characteristics of the mono- and multifilament tapes were conducted. digital.library.unt.edu/ark:/67531/metadc619111/
Advances in fabrication of mono- and multifilament Ag-CLAD BSCCO superconductors
Fabricating long lengths of robust and high-quality conductors is imperative for various applications of high-{Tc} superconductors. Long lengths of mono- and multifilament Ag-clad Bi-Sr-Ca-Cu-0 conductors have been fabricated by the powder-in-tube technique. High values for critical current density (J{sub c}) have been achieved in both short- and long-length conductors. J{sub c} values up to 12,000 A/cm{sup 2} have been achieved in an 850-m-long multifilament conductor. Pancake-shaped coils and test magnets fabricated from long-length conductors were characterized at various temperatures and applied magnetic fields. A magnet containing 770 m of high-{Tc} conductor generated a record high field of {approx} 1 T at 4.2 K in a background field of {approx} 20 T. In-situ tensile and bending characteristics of both mono- and multifilament conductors have also been studied. Multifilament conductors exhibited better axial strain tolerance ({var_epsilon} {approx} 1%) than that of monofilament conductor ({var_epsilon} {approx} 0.2%), while retaining 90% of their initial critical current. An analysis of the results is presented, along with effects of parameters such as thickness, superconductor/Ag ratio, and microstructural details. digital.library.unt.edu/ark:/67531/metadc619851/
Advances in ferroelectric polymers for shock compression sensors
Our studies of the shock compression response of PVDF polymer are continuing in order to understand the physical properties under shock loading and to develop high fidelity, reproducible, time-resolved dynamic stress gauges. New PVDF technology, new electrode configurations and piezoelectric analysis have resulted in enhanced precision gauges. Our new standard gauges have a precision of better than 1% in electric charge release under shock up to 15 GPa. The piezoelectric response of shock compressed PVDF gauges 1 mm{sup 2} in active area has been studied and yielded well-behaved reproducible data up to 20 GPa. Analysis of the response of these gauges in the {open_quotes}thin mode regime{close_quotes} using a Lagrangian hydrocode will be presented. P(VDF-TrFE) copolymers exhibit unique piezoelectric properties over a wide range of temperature depending on the composition. Their properties and phase transitions are being investigated. Emphasis of the presentation will be on key results and implications. digital.library.unt.edu/ark:/67531/metadc691020/
Advances in imaging with thermal neutrons
Experiments have been conducted using a modern high-resolution {sup 3}He two-dimensional position-sensitive detection chamber combined with coded apertures to produce images by means of thermal neutrons. These images are comparable to those produced by gamma ray imaging, but with some important differences. The detector is much less sensitive to the fast neutrons than to the thermalized component. Therefore, assuming that the neutron source has a fission spectrum, the brightest regions in an image represent moderating material in close proximity to the source, rather than the source itself. Earlier experiments have shown that useful contrast can be produced with thermal neutrons using thin masks made of metallic Cd sheet, but the resolution in those experiments was detector-limited at a few centimeters per pixel. The newer detector can resolve a line image with a fwhm resolution of about 1 mm. The technique could in principle be used in re-entry vehicle on-site inspections to count multiple nuclear warheads. Thermal neutrons carry no detailed spectral information, so their detection should not be as intrusive as gamma ray imaging. This technique can be used in nuclear materials management and arms control. digital.library.unt.edu/ark:/67531/metadc680158/
Advances in LIGA-Based Post-Mold Fabrication
The establishment of a process to allow planarization of deep x-ray lithography based microfabncated metal components via diamond lapping has enabled examination of three additional microfabrication issues. The areas of improvement that are discussed include materials, microassembly and packaging, and multilevel fabrication. New materials work has centered on magnetic materials including precision micromagnets and surface treatments of electrodeposited materials. Assembly and packaging has been aided by deep silicon etch processing and the use of conventional precision milling equipment combined with press-tit assembly. Diffhsion bonding is shown to be a particularly important approach to achieving multilevel metal mechanisms and furthermore shows promise for achieving batch assembled and packaged high aspect-ratio metal micromechanics, digital.library.unt.edu/ark:/67531/metadc621732/
Advances in modeling of chemical vapor infiltration for tube fabrication
The forced flow/thermal gradient chemical vapor infiltration process (FCVI) can be used for fabrication of tube-shaped components of ceramic matrix composites. Recent experimental work at Oak Ridge National Laboratory (ORNL) includes process and materials development studies using a small tube reactor. Use of FCVI for this geometry involves significant changes in fixturing as compared to disk-shaped preforms previously fabricated. The authors have used their computer model of the CVI process to simulate tube densification and to identify process modifications that will decrease processing time. This report presents recent model developments and applications. digital.library.unt.edu/ark:/67531/metadc686396/
I. Advances in NMR Signal Processing. II. Spin Dynamics in Quantum Dissipative Systems
No abstract prepared. digital.library.unt.edu/ark:/67531/metadc717784/
Advances in nuclear instrumentation for safeguards
This paper describes detectors, instrumentation, and analytical methods under development to address the above issues. The authors will describe work underway on room-temperature semiconductors including attempts to model the response of these detectors to improve spectrum analysis procedures and detector design. Computerized tomography is used in many medical and industrial applications; they are developing both gamma-ray and neutron tomography for improved measurements of waste and direct-use materials. Modern electronics and scintillation detectors should permit the development of fast neutron coincidence detectors with dramatically improved signal-to-noise ratios. For active measurements, they are studying several improved neutron sources, including a high-fluence, plasma-based, d-t generator. New analysis tools from information theory may permit one to better combine data from different measurement systems. This paper attempts to briefly describe a range of new sensors, electronics, and data analysis methods under study at Los Alamos and other laboratories to promote discussion of promising technology that they may bring to bear on these important global issues. digital.library.unt.edu/ark:/67531/metadc688344/
Advances in orbit drift correction in the advanced photon source storage ring
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. digital.library.unt.edu/ark:/67531/metadc683671/
Advances in oxide-confined vertical cavity lasers
We review the advances made in device fabrication, structure, and performance of vertical-cavity surface emitting lasers (VCSELs) which incorporate the selective oxidation of AlGaAs. digital.library.unt.edu/ark:/67531/metadc671454/
Advances in Photovoltaics at NREL
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. digital.library.unt.edu/ark:/67531/metadc623034/
Advances in processing of Ag-sheathed (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductors.
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. digital.library.unt.edu/ark:/67531/metadc739253/
Advances in PSII Deposited Diamond-Like Carbon Coatings for Use as a Barrier to Corrosion
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. digital.library.unt.edu/ark:/67531/metadc725530/
Advances in the chemical conversion of energetic materials to higher value products
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. digital.library.unt.edu/ark:/67531/metadc734132/
Advances in the determination of quark masses
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. digital.library.unt.edu/ark:/67531/metadc702585/
Advances in the development of FTIR continuous emission monitor for incinerators
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. digital.library.unt.edu/ark:/67531/metadc793433/
Advances in the operation of the DIII-D neutral beam computer systems
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. digital.library.unt.edu/ark:/67531/metadc697220/
Advances in the reduction and compensation of film stress in high-reflectance multilayer coatings for extreme ultraviolet lithography applications
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 a Mo/Si film with 66.5% reflectivity at 13.3 nm were produced with net stress values less than 30 MPa. digital.library.unt.edu/ark:/67531/metadc710268/
Advances in the simulation of toroidal gyro Landau fluid model turbulence
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. digital.library.unt.edu/ark:/67531/metadc688719/
Advances in the TOUGH2 family of general-purpose reservoir simulators
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. digital.library.unt.edu/ark:/67531/metadc666894/
Advances in the use of tomographic inspection techniques for non-destructive analysis of geometric conductor position and correlation with magnetic cross-section modeling
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. digital.library.unt.edu/ark:/67531/metadc712481/
Advances in tubular solid oxide fuel cell technology
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. digital.library.unt.edu/ark:/67531/metadc688051/
Advances in welding science and technology
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. digital.library.unt.edu/ark:/67531/metadc669614/
Advances in x-ray computed microtomography at the NSLS
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. digital.library.unt.edu/ark:/67531/metadc711142/
ADVANCES IN X-RAY COMPUTED MICROTOMOGRAPHY AT THE NSLS.
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. digital.library.unt.edu/ark:/67531/metadc625633/
ADVANCES IN YBCO COATED CONDUCTOR TECHNOLOGY
No abstract prepared. digital.library.unt.edu/ark:/67531/metadc719028/
Advancing Design-for-Assembly: The Next Generation in Assembly Planning
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. digital.library.unt.edu/ark:/67531/metadc672724/
Advancing lighting and daylighting simulation: The transition from analysis to design aid tools
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. digital.library.unt.edu/ark:/67531/metadc792891/
Advancing manufacturing through computational chemistry
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. digital.library.unt.edu/ark:/67531/metadc670616/
Advancing precollege science and mathematics education in San Diego County. Progress report, March 1, 1995--June 30, 1996
This report discusses advancing precollege science and mathematics education in San Diego Count. Described in this report are: curriculum and teacher development; pre-tour material; facility tour; student workbook; evaluation and assessment; and internet access. digital.library.unt.edu/ark:/67531/metadc698162/
Advancing the Technology Base for High Temperature Hydrogen Membranes
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. digital.library.unt.edu/ark:/67531/metadc695477/
Advancing the technology base for high-temperature membranes
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. digital.library.unt.edu/ark:/67531/metadc691951/
The advantages of evaporation of Hafnium in a reactive environment to manufacture high damage threshold multilayer coatings by electron-beam deposition
No abstract prepared. digital.library.unt.edu/ark:/67531/metadc781170/
The advantages of including professionals from different fields of study in the solution of today`s water-related problems
This report presents the details of a meeting of the American Society of Civil Engineers pertaining to water resources and quality. This report suggests an interdisciplinary approach to solving today`s problems dealing with water resources. digital.library.unt.edu/ark:/67531/metadc706596/
Advantages of traveling wave resonant antennas for fast wave heating systems
The resilience of a maximally flat externally coupled traveling wave antenna (TWA) is contrasted with the sensitivity of a simple directly driven resonant loop array to vacuum and plasma conditions in DIII-D. We find a unique synergy between standing and traveling wave resonant TWA components. This synergy extends TWA operation to several passbands between 60 and 120 MHZ, provides 60{degrees}- 120{degrees} tunability between elements within a 1-2 MHZ bandwidth and permits efficient and continuous operation during ELMing H-mode. digital.library.unt.edu/ark:/67531/metadc674952/
Advantages of using a mirror as the first optical component for APS undulator beamlines
The advantages of using a mirror as the first optical component for an APS undulator beamline for thermal management, radiation shielding mitigation, and harmonic rejection are presented. digital.library.unt.edu/ark:/67531/metadc672791/
Adventures in Supercomputing: An innovative program
Within the realm of education, seldom does an innovative program become available with the potential to change an educator`s teaching methodology and serve as a spur to systemic reform. The Adventures in Supercomputing (AiS) program, sponsored by the Department of Energy, is such a program. Adventures in Supercomputing is a program for high school and middle school teachers. It has helped to change the teaching paradigm of many of the teachers involved in the program from a teacher-centered classroom to a student-centered classroom. ``A student-centered classroom offers better opportunities for development of internal motivation, planning skills, goal setting and perseverance than does the traditional teacher-directed mode``. Not only is the process of teaching changed, but evidences of systemic reform are beginning to surface. After describing the program, the authors discuss the teaching strategies being used and the evidences of systemic change in many of the AiS schools in Tennessee. digital.library.unt.edu/ark:/67531/metadc736601/