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Analysis and optimization of an adsorption air conditioner for electric vehicle applications (open access)

Analysis and optimization of an adsorption air conditioner for electric vehicle applications

This paper shows an analysis of the applicability of an adsorption system for electric vehicle (EV) air conditioning. Adsorption systems are designed and optimized to provide the required cooling for four combinations of vehicle characteristics and driving cycles. The resulting adsorption systems are compared with vapor compression air conditioners that can satisfy the cooling load. The objective function is the overall system weight, which includes the cooling system weight and the weight of the battery necessary to provide energy for air conditioner operation. The system with the minimum overall weight is considered to be the best. The results show the optimum values of all the variables, as well as temperatures and amounts adsorbed, for the adsorption and desorption processes. The results indicate that, for the conditions analyzed in this paper, vapor compression air conditioners are superior to adsorption systems, not only because they are lighter, but also because they have a higher COP and are more compact.
Date: July 27, 1994
Creator: Aceves, S. M.
System: The UNT Digital Library
Adsorption air conditioner for electric vehicle applications. Revision 1 (open access)

Adsorption air conditioner for electric vehicle applications. Revision 1

This paper shows an analysis of the applicability of an adsorption system for electric vehicle (EV) air conditioning. Adsorption systems are designed and optimized to provide the required cooling for four combinations of vehicle characteristics and driving cycles. The resulting adsorption systems are compared with vapor compression air conditioners that can satisfy the cooling load. The objective function is the overall system weight, which includes the cooling system weight and the weight of the battery necessary to provide energy for air conditioner operation. The system with the minimum overall weight is considered to be the best, because a lower weight results in an increased vehicle range. The results indicate that, for the conditions analyzed in this paper, vapor compression air conditioners are superior to adsorption systems not only because they are lighter, but also because they have a higher COP and are more compact.
Date: July 27, 1994
Creator: Aceves, S.M.
System: The UNT Digital Library
Scaling behavior in interference lithography (open access)

Scaling behavior in interference lithography

Interference lithography is an emerging, technology that provides a means for achieving high resolution over large exposure areas (approximately 1 m{sup 2}) with virtually unlimited depth of field. One- and two-dimensional arrays of deep submicron structures can be created using near i-line wavelengths and standard resist processing. In this paper, we report on recent advances in the development of this technology, focusing, in particular, on how exposure latitude and resist profile scale with interference period We present structure width vs dose curves for periods ranging from 200 nm to 1 um, demonstrating that deep submicron structures can be generated with exposure latitudes exceeding 30%. Our experimental results are compared to simulations based on PROLITIV2.
Date: February 27, 1998
Creator: Agayan, R.R.; Banyai, W.C. & Fernandez, A.
System: The UNT Digital Library
Phase Diagram of Iron, Revised-Core Temperatures (open access)

Phase Diagram of Iron, Revised-Core Temperatures

Shock-wave experiments on iron preheated to 1,573 K conducted from 14 to 73 GPa, yield new data for sound velocities of the {gamma}- and liquid-phases. Melting was observed in the highest pressure ({approximately} 71 {+-} 2 GPa) experiments at calculated shock temperatures of 2,775 {+-} 160 K. This single crossing of the {gamma}-liquid boundary measured here agrees closely with the {gamma}-iron melting line determined by Boehler [1993], Saxena et al. [1993], and Jephcoat and Besedin [1997]. This {gamma}-iron melting curve is {approximately} 300 C lower than that of Shen et al. [1998b] at 80 GPa.
Date: January 27, 1999
Creator: Ahrens, T.J.; Chen, G.Q. & Holland, K.G.
System: The UNT Digital Library
The regulatory compliance plan for the Minimum Additive Waste Stabilization (MAWS) Program (open access)

The regulatory compliance plan for the Minimum Additive Waste Stabilization (MAWS) Program

The Fernald Environmental Management Project (FEMP) has initiated the Minimum Additive Waste Stabilization (MAWS) Program to demonstrate and evaluate integrated treatment of the FEMP site`s Operable Unit 1 contaminated soils and sludges. The demonstration will require on-site operation of an integrated treatment system consisting of soil washing, water treatment by ion exchange, and vitrification of all contaminated solid wastes at a rate of 300 kg per day. Compliance with all relevant environmental regulations is a major priority of this program. Relevant regulatory requirements come under the jurisdiction of the US Environmental Protection Agency (US EPA), the Ohio Environmental Protection Agency (Ohio EPA), and the Department of Energy (DOE). The plethora of potentially applicable regulations were reviewed and an efficient regulatory compliance strategy developed. This strategy was documented in the MAWS Regulatory Compliance Plan which was presented to the regulatory agencies as a reasonable working plan. The FEMP has found the development of a comprehensive, organized regulatory plan to be critical to the successful implementation of integrated demonstration projects such as the MAWS Program. This paper discusses the approaches used in the MAWS Regulatory Compliance Plan and highlights which could prove useful for others that want to approach the DOE and/or …
Date: January 27, 1993
Creator: Akgunduz, N. K.; Gimpel, R. F. & Finger, S. M.
System: The UNT Digital Library
Z-Pinch Driven Inertial Confinement Fusion Target Physics Research at Sandia National Laboratories (open access)

Z-Pinch Driven Inertial Confinement Fusion Target Physics Research at Sandia National Laboratories

Three hohlraum concepts are being pursued at Sandia National Laboratories (SNL) to investigate the possibility of using pulsed power driven magnetic implosions (z-pinches) to drive high gain targets capable of yields in the range of 200-1000 MJ. This research is being conducted on SNL'S.Z facility that is capable of driving peak currents of 20 MA in z-pinch loads producing implosion velocities as high as 7.5X 107 cm/s, x-ray energies approaching 2 MJ, and x-ray powers exceeding 200 TW. This paper will discuss each of these hohlraum concepts and will overview the experiments that have been conducted on these systems to date.
Date: October 27, 1998
Creator: Alberts, T. E.; Asay, J. R.; Baca, P. M.; Baker, K. L.; Breeze, S. P.; Chandler, G. A. et al.
System: The UNT Digital Library
Adaptive optics high resolution spectroscopy: present status and future direction (open access)

Adaptive optics high resolution spectroscopy: present status and future direction

High resolution spectroscopy experiments with visible adaptive optics (AO) telescopes at Starfire Optical Range and Mt. Wilson have demonstrated that spectral resolution can be routinely improved by a factor of - 10 over the seeing-limited case with no extra light losses at visible wavelengths. With large CCDs now available, a very wide wavelength range can be covered in a single exposure. In the near future, most large ground-based telescopes will be equipped with powerful A0 systems. Most of these systems are aimed primarily at diffraction-limited operation in the near IR. An exciting new opportunity will thus open up for high resolution IR spectroscopy. Immersion echelle gratings with much coarser grooves being developed by us at LLNL will play a critical role in achieving high spectral resolution with a compact and low cost IR cryogenically cooled spectrograph and simultaneous large wavelength coverage on relatively small IR detectors. We have constructed a new A0 optimized spectrograph at Steward Observatory to provide R = 200,000 in the optical, which is being commissioned at the Starfire Optical Range 3.5m telescope. We have completed the optical design of the LLNL IR Immersion Spectrograph (LISPEC) to take advantage of improved silicon etching technology. Key words: adaptive …
Date: July 27, 1999
Creator: Alcock, C.; Angel, R.; Ciarlo, D.; Fugate, R. O.; Ge, J.; Kuzmenko, P. et al.
System: The UNT Digital Library
Multi-Level Micromachined Systems-on-a-Chip: Technology and Applications (open access)

Multi-Level Micromachined Systems-on-a-Chip: Technology and Applications

Researchers at Sandia have recently designed and built several research prototypes, which demonstrate that truly complex mechanical systems can now be realized in a surface micromachined technology. These MicroElectro- Mechanical Systems (MEMS) include advanced actuators, torque multiplying gear tmins, rack and pinion assemblies, positionable mirrors, and mechanical discriminators. All of tile mechanical components are batch fabricated on a single chip of silicon using the infrastructure origimdly developed to support today's highly reliabk; and robust microelectronics industry. Sand ia is also developing the technology 10 integrate microelectronic circuits onto the s,ime piece of silicon that is used to fabricate the MEMS devices. This significantly increases sensitivity and reliability, while fhrther reducing package size and fabrication costs. A review of the MEMS technology and capabilities available at Sandia National Laboratories is presented.
Date: October 27, 1998
Creator: Allen, J. J.; Krygowski, T. W.; Miller, S. L.; Montague, S.; Rodgers, M. S.; Smith, J. H. et al.
System: The UNT Digital Library
Highly-Efficient Laser with Self-Aligned Waveguide and Current Confinement by Selective Oxidation (open access)

Highly-Efficient Laser with Self-Aligned Waveguide and Current Confinement by Selective Oxidation

We report highly efficient, low-threshold-current edge-emitting lasers where both the optical waveguide and lateral current confinement are achieved by lateral selective oxidation of AlGaAs. External differential quantum efficiency in excess of 95% and 40% wall-plug efficiency are demonstrated in 600 {micro}m-long devices without facet coatings. Shorter, 300-{micro}m-long, uncoated devices have <6 mA threshold currents. This high-performance is a combined result of placement of the oxide layers so as to achieve the minimum optical mode volume and bi-parabolic grading of the Al{sub x}Ga{sub 1{minus}x}As heteroepitaxy for minimum height/potential barriers, less than 15 meV, created by the wide-energy-gap layers required for selective wet oxidation. Since the initial development of wet AlGaAs oxidation methods, a number of oxidized edge-emitting laser concepts have been tried. The most successful of these have used lateral selective oxidation of AlGaAs layers between 100 and 300 nm thickness. These layers have been used as current restricting apertures or for both current restriction and lateral waveguiding. Use of an oxide layer above and below the laser active region offers the ability to create a self-aligned waveguide with current apertures on both sides of the pn-junction in a process requiring only one epitaxial growth step. Previous use apertures for these …
Date: July 27, 1999
Creator: Allerman, A.; Blum, O.; Gao, Y. & Vawter, G. A.
System: The UNT Digital Library
Two-Element Phased Array of Anti-Guided Vertical-Cavity Lasers (open access)

Two-Element Phased Array of Anti-Guided Vertical-Cavity Lasers

We demonstrate for the first time anti-guided coupling of two adjacent vertical-cavity surface-emitting lasers (VCSEL's), obtaining a 1-by-2 phase-locked array at 869 nm. The lateral index modification required for anti-guiding is achieved by a patterned 3-rim etch performed between two epitaxial growths. In contrast with prior evanescently coupled VCSEL's, adjacent anti-guided VCSEL's can emit in-phase and produce a single on-axis lobe in the far field. Greater than 2 mW of in-phase output power is demonstrated with two VCSEL's separated by 8 {micro}m. Moreover, phase locking of two VCSEL's separated by 20 {micro}m is observed, indicating the possibility of a new class of optical circuits based upon VCSEL's that interact horizontally and emit vertically.
Date: September 27, 1999
Creator: Allerman, Andrew A.; Choquette, Kent D.; Geib, Kent M.; Hadley, G. Ronald & Serkland, Darwin K.
System: The UNT Digital Library
Domain decomposition methods for a parallel Monte Carlo transport code (open access)

Domain decomposition methods for a parallel Monte Carlo transport code

Achieving parallelism in simulations that use Monte Carlo transport methods presents interesting challenges. For problems that require domain decomposition, load balance can be harder to achieve. The Monte Carlo transport package may have to operate with other packages that have different optimal domain decompositions for a given problem. To examine some of these issues, we have developed a code that simulates the interaction of a laser with biological tissue; it uses a Monte Carlo method to simulate the laser and a finite element model to simulate the conduction of the temperature field in the tissue. We will present speedup and load balance results obtained for a suite of problems decomposed using a few domain decomposition algorithms we have developed.
Date: January 27, 1999
Creator: Alme, H J; Rodrigue, G H & Zimmerman, G B
System: The UNT Digital Library
A Numerical Analysis of 3D EM Imaging from a Single Borehole (open access)

A Numerical Analysis of 3D EM Imaging from a Single Borehole

In this study we analyze the feasibility of three dimensional (3D) electromagnetic (EM) imaging from a single borehole. The proposed logging tool consists of three mutually orthogonal magnetic dipole sources and multiple three component magnetic field receivers. A sensitivity analysis indicates that the most important sensor configuration for providing 3D geological information about the borehole consists of a transmitter with moment aligned parallel to the axis of the borehole, and receivers aligned perpendicular to the axis. The standard coaxial logging configuration provides the greatest depth of sensitivity compared to other configurations, but offers no information regarding 3D structure. Two other tool configurations in which both the source and receiver are aligned perpendicular to the borehole axis provide some directional information and therefore better image resolution, but not true 3D information. A 3D inversion algorithm has been employed to demonstrate the plausibility of 3D inversion using data collected with the proposed logging tool. This study demonstrates that an increase in image resolution results when three orthogonal sources are incorporated into the logging tool rather than a single axially aligned source.
Date: July 27, 1999
Creator: Alumbaugh, David L. & Wilt, Michael J.
System: The UNT Digital Library
The Hanford Site Tank Waste Remediation System: An update (open access)

The Hanford Site Tank Waste Remediation System: An update

The U.S. Department of Energy`s Hanford Site, located in southeastern Washington State, has the most diverse and largest amount of highly radioactive waste in the United States. High-level radioactive waste has been stored in large underground tanks since 1944. Approximately 230,000 m{sup 3} (61 Mgal) of caustic liquids, slurries, saltcakes, and sludges have {sup 137}Cs accumulated in 177 tanks. In addition, significant amounts of {sup 90}Sr and were removed from the tank waste, converted to salts, doubly encapsulated in metal containers., and stored in water basins. A Tank Waste Remediation System Program was established by the U.S. Department of Energy in 1991 to safely manage and immobilize these wastes in anticipation of permanent disposal of the high-level waste fraction in a geologic repository. Since 1991, progress has been made resolving waste tank safety issues, upgrading Tank Farm facilities and operations, and developing a new strategy for retrieving, treating, and immobilizing the waste for disposal.
Date: January 27, 1994
Creator: Alumkal, W. T.; Babad, H.; Harmon, H. D. & Wodrich, D. D.
System: The UNT Digital Library
Report on high energy neutron dosimetry workshop (open access)

Report on high energy neutron dosimetry workshop

The workshop was called to assess the performance of neutron dosimetry per the responses from ten DOE accelerator facilities to an Office of Energy Research questionnaire regarding implementation of a personnel dosimetry requirement in DRAFT DOE 5480.ACC, ``Safety of Accelerator Facilities``. The goals of the workshop were to assess the state of dosimetry at high energy accelerators and if such dosimetry requires improvement, to reach consensus on how to proceed with such improvements. There were 22 attendees, from DOE Programs and contract facilities, DOE, Office of Energy Research (ER), Office of Environmental Safety and Health (EH), Office of Fusion Energy, and the DOE high energy accelerator facilities. A list of attendees and the meeting agenda are attached. Copies of the presentations are also attached.
Date: January 27, 1993
Creator: Alvar, K. R. & Gavron, A.
System: The UNT Digital Library
Report on high energy neutron dosimetry workshop (open access)

Report on high energy neutron dosimetry workshop

The workshop was called to assess the performance of neutron dosimetry per the responses from ten DOE accelerator facilities to an Office of Energy Research questionnaire regarding implementation of a personnel dosimetry requirement in DRAFT DOE 5480.ACC, Safety of Accelerator Facilities''. The goals of the workshop were to assess the state of dosimetry at high energy accelerators and if such dosimetry requires improvement, to reach consensus on how to proceed with such improvements. There were 22 attendees, from DOE Programs and contract facilities, DOE, Office of Energy Research (ER), Office of Environmental Safety and Health (EH), Office of Fusion Energy, and the DOE high energy accelerator facilities. A list of attendees and the meeting agenda are attached. Copies of the presentations are also attached.
Date: January 27, 1993
Creator: Alvar, K.R. & Gavron, A.
System: The UNT Digital Library
Diffractive results from the Tevatron (open access)

Diffractive results from the Tevatron

Hard diffraction in events with dijets and rapidity gaps has been studied by D0 and CDF for three processes: hard color singlet exchange, hard single diffraction, and hard double pomeron exchange, using Tevatron {anti p}p data at {radical}s = 630 GeV and 1.8 TeV. Measurements of rates, {eta}, E{sub T} and {radical}s dependencies are presented and comparisons made with predictions of several models.
Date: May 27, 1999
Creator: Alves, Gilvan A.
System: The UNT Digital Library
A Method for Treating Discretization Error in Nondeterministic Analysis (open access)

A Method for Treating Discretization Error in Nondeterministic Analysis

A response surface methodology-based technique is presented for treating discretization error in non-deterministic analysis. The response surface, or metamodel, is estimated from computer experiments which vary both uncertain physical parameters and the fidelity of the computational mesh. The resultant metamodel is then used to propagate the variabilities in the continuous input parameters, while the mesh size is taken to zero, its asymptotic limit. With respect to mesh size, the metamodel is equivalent to Richardson extrapolation, in which solutions on coarser and finer meshes are used to estimate discretization error. The method is demonstrated on a one dimensional prismatic bar, in which uncertainty in the third vibration frequency is estimated by propagating variations in material modulus, density, and bar length. The results demonstrate the efficiency of the method for combining non-deterministic analysis with error estimation to obtain estimates of total simulation uncertainty. The results also show the relative sensitivity of failure estimates to solution bias errors in a reliability analysis, particularly when the physical variability of the system is low.
Date: January 27, 1999
Creator: Alvin, Kenneth F.
System: The UNT Digital Library
Electrostriction in Field-Structured Composites: Basis for a Fast Artificial Muscle? (open access)

Electrostriction in Field-Structured Composites: Basis for a Fast Artificial Muscle?

The electrostriction of composites consisting of dielectric particles embedded in a gel or elastomer is discussed. It is shown that when these particles are organized by a uniaxial field before gelation, the resulting field-structured composites are expected to exhibit enhanced electrostriction in a uniform field applied along the same axis as the structuring field. The associated stresses might be large enough to form the basis of a polymer-based fast artificial muscle.
Date: January 27, 1999
Creator: Anderson, R. A. & Martin, J. E.
System: The UNT Digital Library
Titanium K-Shell X-Ray Production from High Velocity Wire Arrays Implosions on the 20-MA Z Accelerator (open access)

Titanium K-Shell X-Ray Production from High Velocity Wire Arrays Implosions on the 20-MA Z Accelerator

The advent of the 20-MA Z accelerator [R.B. Spielman, C. Deeney, G.A. Chandler, et al., Phys. Plasmas 5, 2105, (1997)] has enabled implosions of large diameter, high-wire-number arrays of titanium to begin testing Z-pinch K-shell scaling theories. The 2-cm long titanium arrays, which were mounted on a 40-mm diameter, produced between 75{+-}15 to 125{+-}20 kJ of K-shell x-rays. Mass scans indicate that, as predicted, higher velocity implosions in the series produced higher x-ray yields. Spectroscopic analyses indicate that these high velocity implosions achieved peak electron temperatures from 2.7{+-}0.1 to 3.2{+-}0.2 keV and obtained a K-shell emission mass participation of up to 12%.
Date: January 27, 1999
Creator: Apruzese, J.P.; Beg, F.N.; Clark, R.C.; Coverdale, C.A.; Davis, J.; Deeney, C. et al.
System: The UNT Digital Library
Dynamics of Wet Oxidation of High-AL-Content III-V Materials (open access)

Dynamics of Wet Oxidation of High-AL-Content III-V Materials

Oxidation of layers of high-Al-content III-V materials by water vapor has become the enabling process for high-efficiency vertical cavity surface emitting lasers (VCSELS) and has potential applications for reducing substrate current leakage in GaAs-on-insulator (GOI) MESFETS. Because of the established importance of wet oxidation in optoelectronic devices and its potential applications in electronic devices, it has become increasingly important to understand the mechanism of wet oxidation and how it might be expected to affect both the fabrication and subsequent operation of devices that have been made using this technique. The mechanism of wet oxidation and the consequence of this mechanism for heterostructure design and ultimate device operation are discussed here.
Date: January 27, 1999
Creator: Ashby, C.I.H.
System: The UNT Digital Library
Chemical identity of atoms using core electron annihilations (open access)

Chemical identity of atoms using core electron annihilations

Positron annihilation spectroscopy is a sensitive probe for studying the electronic structure of defects in solids. The high momentum part of the Doppler-broadened annihilation spectra can be used to distinguish different elements. This is achieved by using a new two-detector coincidence system and by imposing appropriate kinematic cuts to exclude background events. The new setup improves the peak to background ratio in the annihilation spectrum to {approximately}10{sup 5}. As a result, the line shape variations arising from different core electrons can be studied. The new approach adds elemental specificity to the Doppler broadening technique, and is useful in studying elemental variations around a defect site. Results from several case studies are reviewed.
Date: June 27, 1997
Creator: Asoka-Kumar, P.
System: The UNT Digital Library
Polymer Aging Techniques Applied to Degradation of a Polyurethane Propellant Binder (open access)

Polymer Aging Techniques Applied to Degradation of a Polyurethane Propellant Binder

The oxidative thermal aging of a crosslinked hydroxy-terminated polybutadiene (HTPB)/isophorone diisocyanate (IPDI) polyurethane rubber, commonly used as the polymeric binder matrix in solid rocket propellants, was studied at temperatures of RT to 125 C. We investigate changes in tensile elongation, mechanical hardening, polymer network properties, density, O{sub 2} permeation and molecular chain dynamics using a range of techniques including solvent swelling, detailed modulus profiling and NMR relaxation measurements. Using extensive data superposition and highly sensitive oxygen consumption measurements, we critically evaluate the Arrhenius methodology, which normally assumes a linear extrapolation of high temperature aging data. Significant curvature in the Arrhenius diagram of these oxidation rates was observed similar to previous results found for other rubber materials. Preliminary gel/network properties suggest that crosslinking is the dominant process at higher temperatures. We also assess the importance of other constituents such as ammonium perchlorate or aluminum powder in the propellant formulation.
Date: July 27, 1999
Creator: Assink, R. A.; Celina, M.; Graham, A. C. & Minier, L. M.
System: The UNT Digital Library
Use of alternating-Z doubling in high-dynamic-range tripling: design and evaluation of an optimized prototype tripler (open access)

Use of alternating-Z doubling in high-dynamic-range tripling: design and evaluation of an optimized prototype tripler

We designed and tested an alternating-Z tripler that consisted of two detuned, Type-1, potassium dihydrogen phosphate (KD*P) doublers and one KD*P mixer. The crystal thicknesses were, respectively, 13, 10 and 10 mm, and the detunings of the doublers were +420 and -520 µrad. All three crystals were fabricated from 80% deuterated KDP. Conversion efficiency was measured and calculated for input 1053- nm pulses with approximately rectangular waveforms and durations of either 1 or 6 ns, and for 20-ns pulses that exhibited intensity variation by a factor of 10. The measured peak conversion efficiency was more than 80%, and energy conversion efficiencies ranged from 62-80% depending on the waveform of the input pulse. The expected large dynamic range in input intensity, 9-10, was observed, and the measured and calculated efficiencies were in excellent agreement.
Date: July 27, 1998
Creator: Auerbach, J. M.; Barker, C.; Eimerl, D.; Milan, D. & Milonni, P. W.
System: The UNT Digital Library
Perturbation theory for frequency doubling and tripling of electric field amplitude and phase ripples (open access)

Perturbation theory for frequency doubling and tripling of electric field amplitude and phase ripples

A perturbation theory has been developed to calculate the transfer of electric field amplitude and phase ripples from the first harmonic to either the second harmonic or the third harmonic. The theory is restricted to steady-state conversion processes. In the case of small phase gradients, the real and imaginary parts of the output harmonic ripple are related to the real and imaginary parts of the input perturbation by a 2 {times} 2 matrix. To confirm the validity of the perturbation theory, we have performed an initial set of experiments on the Optical Sciences Laser to investigate the transfer of a weak ripple from the first harmonic to the second harmonic.
Date: June 27, 1995
Creator: Auerbach, J. M.; Eimerl, D.; Hunt, J. T.; Milam, D.; Trenholme, J. B. & Milonni, P. W.
System: The UNT Digital Library