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Parallel sphere rendering

Description: Sphere rendering is an important method for visualizing molecular dynamics data. This paper presents a parallel algorithm that is almost 90 times faster than current graphics workstations. To render extremely large data sets and large images, the algorithm uses the MIMD features of the supercomputers to divide up the data, render independent partial images, and then finally composite the multiple partial images using an optimal method. The algorithm and performance results are presented for the CM-5 and the M.
Date: October 1, 1996
Creator: Krogh, M.; Painter, J. & Hansen, C.
Partner: UNT Libraries Government Documents Department

Frame work on an on-line regulations expert permit server, Semi-annual technical progress report, September 25, 1996--March 24, 1997

Description: The Interstate Oil and Gas Compact Commission and its member states have become increasingly concerned about environmental compliance costs for the petroleum exploration and production industry with estimated costs for 1990 at about $2 billion. Over the last decade, these costs have increased at a rate of 3 to 5% per year. At a time when regulatory and environmental needs and costs are increasing, major oil companies are restructuring and reducing staffs. The places an increased burden on the remaining personnel charged with regulatory compliance duties. As major oil producers have begun to concentrate on their more profitable overseas properties, they have created a greater role for the approximately 8000 independent oil and gas producers in the U.S. with many being small independent producers with limited staff. With small staffs, the independents lack the infrastructure to address an increasingly important aspect of production operations: compliance with environmental regulations. Depending on the level of industry activity, the oil and gas industry could incur an additional $16 to $24 billion in increased environmental compliance expenditures by the end of the 1990`s. At current oil prices, the abandonment of remaining resources in known oil reservoirs could be accelerated by approximately ten years, and up to 30% of currently producing resources could be immediately abandoned because of increased regulations. Transferring new and innovative technologies to the industry can help defer reservoir abandonments, improve regulatory compliance, lower the costs of compliance, reduce risk, and help assure the development of new domestic resources.
Date: March 24, 1997
Creator: Hansen, C.
Partner: UNT Libraries Government Documents Department

Cost-effective data-parallel load balancing

Description: Load balancing algorithms improve a program`s performance on unbalanced datasets, but can degrade performance on balanced datasets, because unnecessary load redistributions occur. This paper presents a cost-effective data-parallel load balancing algorithm which performs load redistributions only when the possible savings outweigh the redistribution costs. Experiments with a data-parallel polygon renderer show a performance improvement of up to a factor of 33 on unbalanced datasets and a maximum performance loss of only 27 percent on balanced datasets when using this algorithm.
Date: May 1, 1995
Creator: Hansen, C.D. & Ahrens, J.P.
Partner: UNT Libraries Government Documents Department

Parallel rendering techniques for massively parallel visualization

Description: As the resolution of simulation models increases, scientific visualization algorithms which take advantage of the large memory. and parallelism of Massively Parallel Processors (MPPs) are becoming increasingly important. For large applications rendering on the MPP tends to be preferable to rendering on a graphics workstation due to the MPP`s abundant resources: memory, disk, and numerous processors. The challenge becomes developing algorithms that can exploit these resources while minimizing overhead, typically communication costs. This paper will describe recent efforts in parallel rendering for polygonal primitives as well as parallel volumetric techniques. This paper presents rendering algorithms, developed for massively parallel processors (MPPs), for polygonal, spheres, and volumetric data. The polygon algorithm uses a data parallel approach whereas the sphere and volume render use a MIMD approach. Implementations for these algorithms are presented for the Thinking Ma.chines Corporation CM-5 MPP.
Date: July 1, 1995
Creator: Hansen, C.; Krogh, M. & Painter, J.
Partner: UNT Libraries Government Documents Department

Approximations for the thermodynamic and transport properties of high-temperature air

Description: Report presenting the thermodynamic and transport properties of high-temperature air in closed form starting from approximate partition functions for the major components in air and neglecting all minor components. The compressibility, energy, entropy, specific heats, speed of sound, coefficients of viscosity and thermal conductivity, and Prandtl numbers for air are provided for a range of temperatures and pressures.
Date: March 1958
Creator: Hansen, C. Frederick
Partner: UNT Libraries Government Documents Department

The erosion of meteors and high-speed vehicles in the upper atmosphere

Description: From Summary: "A simple inelastic collision model of meteor-atmosphere interaction is used and analytic relations for velocity, deceleration, size, and relative luminous magnitude of meteors are derived and expressed in dimensionless parametric form. The analysis is compared with available quantitative observations of meteor behavior and it is indicated that a large fraction of the atmospheric bombardment energy is used in eroding meteor material. The erosion from large, high-speed vehicles as they traverse the high-altitude, free-molecule portion of the atmosphere is calculated, on the assumption that the vaporization process is similar to that which occurs for meteors."
Date: March 1957
Creator: Hansen, C. Frederick
Partner: UNT Libraries Government Documents Department

Photon burst mass spectrometry for the measurement of {sup 85}Kr at ambient levels

Description: Photon Burst Mass Spectrometry has been used to measure {sup 85}Kr in a sample with an abundance of 6 x 10{sup {minus}9}. Improvements in detection efficiency by the use of avalanche photodiodes cooled to liquid nitrogen temperature are reported, which should make possible measurement of {sup 85}Kr at the ambient atmospheric abundance of 10{sup {minus}11}. Potential applications include nuclear monitoring, atmospheric transport, and dating young ground water up to 40 years.
Date: December 1, 1998
Creator: Fairbank, W.M. Jr.; LaBelle, R.D. & Hansen, C.S.
Partner: UNT Libraries Government Documents Department

The ACL Message Passing Library

Description: This paper presents the ACL (Advanced Computing Lab) Message Passing Library. It is a high throughput, low latency communications library, based on Thinking Machines Corp.`s CMMD, upon which message passing applications can be built. The library has been implemented on the Cray T3D, Thinking Machines CM-5, SGI workstations, and on top of PVM.
Date: September 1, 1995
Creator: Painter, J.; McCormick, P.; Krogh, M.; Hansen, C. & Colin de Verdiere, G.
Partner: UNT Libraries Government Documents Department

ACLMPL: Portable and efficient message passing for MPPs

Description: This paper presents the Advanced Computing Lab Message Passing Library (ACLMPL). Modeled after Thinking Machines Corporation`s CMMD, ACLMPL is a high throughout, low latency communications library for building message passing applications. The library has been implemented on the Cray T3D, Thinking Machines CM-5, SGI workstations, and on top of PVM. On the Cray T3D, benchmarks show ACLMPL to be 4 to 7 times faster than MPI or PVM.
Date: September 19, 1995
Creator: Painter, J.; Krogh, M.; Hansen, C.; McCormick, P. & de Verdiere, G.C.
Partner: UNT Libraries Government Documents Department

Parallel sphere rendering

Description: Sphere rendering is an important method for visualizing molecular dynamics data. This paper presents a parallel divide-and-conquer algorithm that is almost 90 times faster than current graphics workstations. To render extremely large data sets and large images, the algorithm uses the MIMD features of the supercomputers to divide up the data, render independent partial images, and then finally composite the multiple partial images using an optimal method. The algorithm and performance results are presented for the CM-5 and the T3D.
Date: May 1, 1995
Creator: Krogh, M.; Hansen, C.; Painter, J. & de Verdiere, G.C.
Partner: UNT Libraries Government Documents Department

Condensation of air in supersonic wind tunnels and its effects on flow about models

Description: Report presenting the results of an investigation of condensation phenomena in supersonic wind tunnel. Lower and upper limits for the degree of supersaturation attainable before the onset of condensation of air are discussed. A method is presented for calculating the properties of a stream containing a small fraction of condensed air.
Date: April 1952
Creator: Hansen, C. Frederick & Nothwang, George J.
Partner: UNT Libraries Government Documents Department

X-ray instrumentation for density measurements in a supersonic flow field

Description: Report describing an instrument based on the principle that an x-ray beam is essentially undeviated while traversing a short path in air. It was used to measure the product of air density and the path length in the 10- by 14-inch supersonic wind tunnel. The measurements obtained were accomplished by comparing the intensity of two beams from the same X-ray source.
Date: December 1952
Creator: Dimeff, John; Hallet, Ralph K., Jr. & Hansen, C. Frederick
Partner: UNT Libraries Government Documents Department

A review of the thermodynamic, transport, and chemical reaction rate properties of high-temperature air

Description: Thermodynamic and transport properties of high temperature air, and the reaction rates for the important chemical processes which occur in air, are reviewed. Semiempirical, analytic expressions are presented for thermodynamic and transport properties of air. Examples are given illustrating the use of these properties to evaluate (1) equilibrium conditions following shock waves, (2) stagnation region heat flux to a blunt high-speed body, and (3) some chemical relaxation lengths in stagnation region flow.
Date: July 1958
Creator: Hansen, C. Frederick & Heims, Steve P.
Partner: UNT Libraries Government Documents Department

Stagnation-point heat transfer to blunt shapes in hypersonic flight, including effects of yaw

Description: An approximate theory is developed for predicting the rate of heat transfer to the stagnation region of blunt bodies in hypersonic flight. Attention is focused on the case where wall temperature is small compared to stagnation temperature. The theoretical heat-transfer rate at the stagnation point of a hemispherical body is found to agree with available experimental data. The effect of yaw on heat transfer to a cylindrical stagnation region is treated at some length, and it is predicted that large yaw should cause sizable reductions in heat-transfer rate.
Date: April 1958
Creator: Eggers, A. J., Jr.; Hansen, C. Frederick & Cunningham, Bernard E.
Partner: UNT Libraries Government Documents Department

Investigation of a rotary valving system with variable valve timing for internal combustion engines: Final technical report

Description: The objective of the program was to provide a functional demonstration of the Hansen Rotary Valving System with Variable Valve timing (HRVS/VVT), capable of throttleless inlet charge control, as an alternative to conventional poppet-valves for use in spark ignited internal combustion engines. The goal of this new technology is to secure benefits in fuel economy, broadened torque band, vibration reduction, and overhaul accessibility. Additionally, use of the variable valve timing capability to vary the effective compression ratio is expected to improve multi-fuel tolerance and efficiency. Efforts directed at the design of HRVS components proved to be far more extensive than had been anticipated, ultimately requiring that proof-trial design/development work be performed. Although both time and funds were exhausted before optical or ion-probe types of in-cylinder investigation could be undertaken, a great deal of laboratory data was acquired during the course of the design/development work. This laboratory data is the basis for the information presented in this Final Report.
Date: November 18, 1994
Creator: Cross, P. C. & Hansen, C. N.
Partner: UNT Libraries Government Documents Department

Weather-Corrected Performance Ratio

Description: Photovoltaic (PV) system performance depends on both the quality of the system and the weather. One simple way to communicate the system performance is to use the performance ratio (PR): the ratio of the electricity generated to the electricity that would have been generated if the plant consistently converted sunlight to electricity at the level expected from the DC nameplate rating. The annual system yield for flat-plate PV systems is estimated by the product of the annual insolation in the plane of the array, the nameplate rating of the system, and the PR, which provides an attractive way to estimate expected annual system yield. Unfortunately, the PR is, again, a function of both the PV system efficiency and the weather. If the PR is measured during the winter or during the summer, substantially different values may be obtained, making this metric insufficient to use as the basis for a performance guarantee when precise confidence intervals are required. This technical report defines a way to modify the PR calculation to neutralize biases that may be introduced by variations in the weather, while still reporting a PR that reflects the annual PR at that site given the project design and the project weather file. This resulting weather-corrected PR gives more consistent results throughout the year, enabling its use as a metric for performance guarantees while still retaining the familiarity this metric brings to the industry and the value of its use in predicting actual annual system yield. A testing protocol is also presented to illustrate the use of this new metric with the intent of providing a reference starting point for contractual content.
Date: April 1, 2013
Creator: Dierauf, T.; Growitz, A.; Kurtz, S.; Cruz, J. L. B.; Riley, E. & Hansen, C.
Partner: UNT Libraries Government Documents Department

Pulsations of the R Coronae Borealis stars

Description: The radial pulsations of very luminous, low-mass models (L/M approx. 10/sup 4/, solar units), which are possible representatives of the R CrB stars, have been examined. These pulsations are extremely nonadiabatic. There are in some cases at least one extra (strange) mode which makes interpretation difficult. The blue instability edges are also peculiar, in that there is an abrupt excursion of the blue edge to the blue for L/M sufficiently large. The range of periods of the model encompasses observed periods of the Cepheid-like pulsations of actual R CrB stars.
Date: January 1, 1980
Creator: Cox, J.P.; King, D.S.; Cox, A.N.; Wheeler, J.C.; Hansen, C.J. & Hodson, S.W.
Partner: UNT Libraries Government Documents Department

Photon burst mass spectrometry--ultrasensitive detection of rare isotopes

Description: Progress is reported on the development of a new technique for measurement of trace levels of radioisotopes which is based on fluorescence detection of output from a mass spectrometer. Significant achievements include the observation of fluorescence and burst signals from Kr isotopes, including enriched samples of {sup 85}Kr with a 4-collector system. An abundance sensitivity is demonstrated with {sup 83}Kr and {sup 85}Kr.
Date: February 1, 1995
Creator: Hansen, C.S.; Pan, X.J.; Fairbank, W.M. Jr.; Oona, H.; Chamberlin, E.P.; Nogar, N.S. et al.
Partner: UNT Libraries Government Documents Department

Three-color resonance ionization spectroscopy of Zr in Si

Description: It has been proposed that the composition of the solar wind could be measured directly by transporting ultrapure collectors into space, exposing them to the solar wind, and returning them to earth for analysis. In a study to help assess the applicability of present and future postionization secondary neutral mass spectrometers for measuring solar wind implanted samples, measurements of Zr in Si were performed. A three-color resonant ionization scheme proved to be efficient while producing a background count rate limited by secondary ion signal (5 x 10{sup {minus}4} counts/laser pulse). This lowered the detection limit for these measurements to below 500 ppt for 450,000 averages. Unexpectedly, the Zr concentration in the Si was measured to be over 4 ppb, well above the detection limit of the analysis. This high concentration is thought to result from contamination during sample preparation, since a series of tests were performed that rule out memory effects during the analysis.
Date: September 1, 1996
Creator: Hansen, C.S.; Calaway, W.F.; Pellin, M.J.; Wiens, R.C. & Burnett, D.S.
Partner: UNT Libraries Government Documents Department

Measurement of trace isotopes by photon burst mass spectrometry

Description: Progress is reported on the development of a new laser- and mass spectrometer-based technique for measurement of trace levels of radioisotopes. Significant results to date include the demonstration of high efficiency and throughput in a mass spectrometer, efficient production of metastable atoms from Ar{sup +} and Kr{sup +} beams, a demonstration of the photon burst detector principle with Mg{sup +} ions, and the verification of zero background in a two-detector system. 7 refs., 5 figs.
Date: January 1, 1991
Creator: Fairbank, W.M. Jr.; Hansen, C.S.; LaBelle, R.D.; Pan, X.J. (Colorado State Univ., Fort Collins, CO (USA). Dept. of Physics); Chamberlin, E.P.; Fearcy, B.L. et al.
Partner: UNT Libraries Government Documents Department

A search for. mu. yields e. gamma. at the level of 10 sup minus 13

Description: The status of the MEGA experiment is described. It is a search for the decay {mu} {r arrow} e{gamma} with a branching ratio sensitivity of approximately 10{sup {minus}13}. The observation of this decay would indicate the existence of physics outside the standard model of electroweak interactions. The experiment employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with on-line filters. The detectors are contained in a 1.5 T solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the detector design have been validated in engineering runs; data taking will begin in 1990 with most of the electron arm and one pair spectrometer layer installed. 5 refs., 4 figs.
Date: January 1, 1990
Creator: Amann, J.F.; Black, K.; Bolton, R.D.; Carius, S.; Cooper, M.D.; Foreman, W. et al.
Partner: UNT Libraries Government Documents Department