Digital Commons Network^™

Country/Region Reports -- United States Of America, Linda A. Malone

Faculty Publications

No abstract provided.

Observation Of Hard Scattering In Photoproduction At Hera, M. Derrick, D. Krakauer, S. Magill, B. Musgrave, J. Repond, K. Sugano, R. Stanek, R. L. Talaga, J. Thron, F. Arzarello, R. Ayed, G. Barbagli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, G. Bruni, P. Bruni, G. Cara Romeo, G. Castellini, M. Chiarini, L. Cifarelli, F. Cindolo, F. Ciralli, A. Contin, S. D'Auria, C. Del Papa, F. Frasconi, P. Giusti, G. Iacobucci, G. Laurenti, G. Levi, Q. Lin

Faculty Publications

We report a study of electron proton collisions at very low Q2, corresponding to virtual photoproduction at centre of mass energies in the range 100-295 GeV. The distribution in transverse energy of the observed hadrons is much harder than can be explained by soft processes. Some of the events show back-to-back two-jet production at the rate and with the characteristics expected from hard two-body scattering. A subset of the two-jet events have energy in the electron direction consistent with that expected from the photon remnant in resolved photon processes. © 1992.

Photopolymer-Based Stratified Volume Holographic Optical Elements, Gregory P. Nordin, A. R. Tanguay

Faculty Publications

We report the implementation of stratified volume holographic optical elements (SVHOE's) using DuPont's Omnidex holographic photopolymer material and an in situ exposure technique for simultaneous multilayer grating recording. Experimental measurement of the +1-order angular sensitivity of a seven-layer SVHOE structure shows remarkable agreement with both theory and numerical simulation for incidence angles near the Bragg angle. For SVHOE's having modulation layers that individually operate in the Bragg or transition diffraction regimes, the envelope of the SVHOE angular sensitivity is experimentally shown to approximate closely that of a single modulation layer.

Diffraction Properties Of Stratified Volume Holographic Optical Elements, Gregory P. Nordin, R. V. Johnson, A. R. Tanguay

Faculty Publications

We present a unified treatment of the diffraction properties of stratified volume holographic optical elements (SVHOE's). We show that the relative phasing of the diffraction orders as they propagate from layer to layer gives rise to a unique notched diffraction response of the +1 order (for the case of Bragg incidence) as a function of the normalized buffer-layer thickness, the grating spatial frequency, and the readout wavelength. For certain combinations of these parameters Bragg diffraction behavior characteristic of volume holographic optical elements (VHOE's) is observed, whereas for other combinations pure Raman-Nath behavior periodically recurs. By using these same relative-phasing arguments, …

Use Of Raman Spectroscopy In Characterizing Soft X-Ray Multilayers: Tools In Understanding Structure And Interfaces, Ming Cai, Qi Wang, David D. Allred, Larry V. Knight, Dorian M. Hatch, A. Reyes-Mena, Guizhong Zhang

Faculty Publications

Our group is studying the structure and interfaces of soft x-ray multilayers by various techniques including x-ray diffraction and Raman spectroscopy. Raman spectroscopy is particularly useful since it is sensitive to the identity of individual bonds and thus can potentially characterize the abruptness of interfaces in multilayers. Blocking interfacial mixing is very important in achieving and maintaining high reflectivity. We report our studies of the as-deposited and postannealed structure of Mo/Si and W/C multilayers. The Mo/Si system is probably the most widely studied multilayer currently because of its potential applications for soft x-ray projection lithography for the range of 13 …

Causation In Fact In Omission Cases, David A. Fischer

Faculty Publications

This article analyzes the difficulties involved in attributing cause in fact in omission cases, and suggests possible resolutions. Part II discusses the basic concept of causation, and the distinction between acts and omissions. Part III discusses the particular problems that arise in applying causation principles in omission cases. Part IV then analyzes these problems from both corrective justice and economic analysis perspectives. Finally, the article suggests an approach for solving these complex issues.

Drying Of Beulah-Zap Lignite, Karl S. Vorres, David L. Wertz, Vivak Malhotra, Yuhong Dang, J.T. Joseph, Ronald Fisher

Faculty Publications

Lignite dried in a stream of dry nitrogen at moderate temperatures (20-80-degrees-C) loses water in two distinguishable modes. The first mode represents about 80-85% of the loss of moisture. The second represents the other 15-20% lost under these conditions. The rate follows a unimolecular mechanism (like radioactive decay) for each mode. The activation energy for the first mode is close to the heat of vaporization of water. The rate is dependent upon the gas flow around the sample and the weight (or thickness) of the sample. Work at Amoco Oil Company indicated that the oil yield was higher for the …

Heterogeneity Of Intergranular Damage In Copper Crept In Plane-Strain Tension, Brent L. Adams, David P. Field

Faculty Publications

The authors wish to acknowledge support of this work by the Office of Basic Energy Sciences of the U. S. Department of Energy. An interface damage function (IDF), which statistically describes the area fraction of interface damage as a function of up to eight parameters defining crystallite interfaces, was determined for commercial purity copper specimens crept in plane strain tension. The IDF was determined from stereological parameters measured on plane sections cut through damaged specimens. The eight-dimensional space of the function was investigated by analyzing two-dimensional projections of the complete domain. Certain special interfaces were observed to damage preferentially. A …

An Improved Choice: The Virginia Limited Liability Company, James J. Wheaton

Faculty Publications

When the General Assembly adopted the Virginia Limited Liability Company Act (the "Act")' in 1991, Virginia joined just four other states in recognizing the potential of a relatively obscure business entity, the limited liability company ("LLC"). The LLC concept has spread rapidly since the adoption of the Virginia Act early last year. Three other states enacted LLC legislation in 1991, and in just the first few months of 1992, six more states followed the trend.

[...]

Although the number of LLCs formed in Virginia since the Virginia Act took effect last July displays the willingness of Virginia attorneys to recommend …

Multiplication, Division, And Shift Instructions In Parallel Random Access Machines, Jerry L. Trahan, Michael C. Loui, Vijaya Ramachandran

Faculty Publications

We prove that polynomial time on a parallel random access machine (PRAM) with unit-cost multiplication and division or on a PRAM with unit-cost shifts is equivalent to polynomial space on a Turing machine (PSPACE). This extends the result that polynomial time on a basic PRAM is equivalent to PSPACE to hold when the PRAM is allowed multiplication or division or unrestricted shifts. It also extends to the PRAM the results that polynomial time on a random access machine (RAM) with multiplication is equivalent to PSPACE and that polynomial time on a RAM with shifts (that is, a vector machine) is …

Interface Cavitation Damage In Polycrystalline Copper, Brent L. Adams, David P. Field

Faculty Publications

The authors acknowledge the support of the Office of Basic Energy Sciences of the United States Department of Energy. Determination of an interface damage function (IDF) from a stereological procedure similar to that presented by Hilliard is described. The mathematical and experimental simplicity of the method is utilized in measuring an IDF for polycrystalline copper crept at 0.6T sub m under uniaxial tension. Whereas previous work focused on a five parameter description of the local state of a grain boundary, the domain of the IDF is increased to eight degrees of freedom in the present study to include the complete …

Experimental Measurement Of Rov Tether Tension, Tim W. Mclain, S M. Rock

Faculty Publications

In the undersea operation of a tethered ROV system, the pilot's ability to control precisely the ROV is often limited by disturbance forces generated by drag due to currents that act either directly on the ROV or indirectly on the ROV through the tether. The objective of this research, which was conducted at the Monterey Bay Aquarium Research Institute (MBARI), was to characterize the magnitude and dynamics of tether forces by measuring them during operation. To achieve this, a tether tension sensor and data logging system were developed. This system was used to measure the forces in the tether of …

Effects Of Fall Fertilizer Applications Of Mitotic Index And Bud Dormancy Of Loblolly Pine Seedlings, Hans Michael Williams, David B. South

Faculty Publications

A series of studies examined the effects of fall fertilization with diammoniwn phosphate (DAP) on mitotic index and bud donnancy [as measured by mean days to budbreak (DBB)] of two half-sib seed sources of loblolly pine. The first study tested different rates of DAP (0, 67, and 202 kg Nlha), the second study compared DAP with ammoniwnnitrate, and the third study examined the effect of different application dates (September 28, October 19, and November 9). An increase in mitotic index of unfertilized seedlings was observed during October and was due to developmental activity which follows initial budset. Differences in mitotic …

Note On The Number Dependence Of Nonequilibrium Molecular Dynamics Simulations Of The Viscosity Of Structured Molecules, Richard L. Rowley, James F. Ely

Faculty Publications

Nonequilibrium molecular dynamics simulations have been performed for a system of 512 four-site models representing n-butane molecules. The results are compared to simulations previously reported for 125 molecules to check a recently reported number dependence in such simulations. A small system size dependence was observed at low shear rates, but the rheological behavior is not affected. Considerably greater certainty is obtained using larger systems.

Effect Of Co2 On The Processing Of Y-Ba-Cu-O Superconductors, C. Zhang, Guna S. Selvaduray

Faculty Publications

The superconducting properties of YBa2Cu3O6+x reacted with various known ratios of O2/CO2 gas mixtures during sintering at different temperatures were studied. Jc was found to decrease drastically upon reaction with CO2, becoming zero at certain CO2 activities. The stability region for the 123 superconductor, as a function of CO2 activity and temperature, was empirically formulated as follows: log pCO2 < (−45,000)/T + 33.4. The grain boundaries in sintered samples with Jc = 0 were investigated with HRTEM in conjunction with EDS. Two distinct types of grain boundaries were observed. Approximately 10% of the grain boundaries were wet by a thin layer of a second phase, deduced to be BaCuO2. The remaining boundaries were sharp grain boundaries. The grain structure near the sharp grain boundaries was tetragonal. These two types of grain boundaries are thought to be responsible for Jc being zero.

Unequal Error Protection Qpsk Modulation Codes, Robert H. Morelos-Zaragoza, Shu Lin

Faculty Publications

The authors use binary linear UEP (LUEP) codes, in combination with a QPSK signal set and Gray mapping, to obtain new efficient block QPSK modulation codes with unequal minimum squared Euclidean distances. They give several examples of codes that have the same minimum squared Euclidean distance as the best QPSK modulation codes of the same rate and length. A new suboptimal two-stage soft-decision decoding is applied to LUEP QPSK modulation codes.

A Note On After-Tax Analysis Where Capitalized Costs Are Depreciated, Steven H. Bullard, Thomas J. Straka

Faculty Publications

Forest management often requires relatively long-term and capital intensive investments. Economic analysis of timber management alternatives can therefore be an extremely important aspect of decision-making. Investment analysis techniques are prominent in forest management texts and have also been the subject of many articles in the forestry literature.

Any forestry investment analysis involves several important aspects. Topics included in reports by Gunter and Haney (1984) and Bullard et al. (1986), for example, include the treatment of inflation, income taxes, risk, and the choice of an appropriate discount rate. In this article, we focus on a very specific aspect of after-tax investment …

Can Governmental Action Shield Otherwise Commercial Activity Under The Foreign Sovereign Immunities Act?, Michael P. Waxman

Faculty Publications

No abstract provided.

Causal Comparisons, Robert N. Strassfeld

Faculty Publications

Focusing on the multiple meanings of the statement "A was a more important cause of C than was B," Professor Strassfeld considers the feasibility of comparative causation as a means of apportioning legal responsibility for harms He concludes that by combining two different interpretations of "more important cause"--judgments of comparative counterfactual similarity and the Uniform Comparative Fault Act approach of comparative responsibility-we can effectively make causal comparisons and avoid the effort to compare such incommensurables as the defendant's fault under a strict liability standard and the plain- tiff's fault for failure to exercise reasonable care

Effects Of Temperature On Methane Consumption In A Forest Soil And In Pure Cultures Of The Methanotroph Methylomonas Rubra, G. M. King, A. P.S. Adamsen

Faculty Publications

Methane oxidation in soil cores from a mixed hardwood-coniferous forest varied relatively little as a function of incubation temperatures from -1 to 30°C. The increase in oxidation rate was proportional to T2.4 (in kelvins). This relationship was consistent with limitation of methane transport through a soil gas phase to a subsurface zone of consumption by diffusion. The Q10 for CO2 production, 3.4, was substantially higher than that for methane oxidation, 1.1, and indicated that the response of soil respiration to temperature was limited by enzymatic processes and not diffusion of either organic substrates or molecular oxygen. When grown under conditions …

Government Regulation Of Religiously Based Social Services: The First Amendment Considerations, Carl H. Esbeck

Faculty Publications

A daunting welter of variables confronts anyone who sets out to systematize the First Amendment's effect on the government's role in regulating social services operated by religious organizations. The task is further complicated because the regulations in question often were promulgated as a consequence of the monitoring that inevitably accompanies government spending on private-sector welfare programs. The most suitable methodology should take into account: 1) the nature of the organizations that are the object of the government's regulation or program of aid; 2) the interrelationship between government and religious organizations that results from the regulation or aid; and 3) the …

Collection Development Policy: Academic Library, St. Mary's University, Margaret Sylvia

Faculty Publications

A revised edition of the original collection development policy for the Academic Library (now the Louis J. Blume Library) published in ERIC. This guide spells out the collection development policy of the library of St. Mary's University in San Antonio, Texas. The guide is divided into the following five topic areas: (1) introduction to the community served, parameters of the collection, cooperation in collection development, and priorities of the collection; (2) considerations in collection development, including maintaining the collection, gifts, bibliographic instruction, circulation, and intellectual freedom; (3) selection of materials, including responsibility for selection, selection aids, and criteria for selection …

Extensions Of Tutte's Wheels-And-Whirls Theorem, Collette R. Coullard, James G. Oxley

Faculty Publications

Tutte's wheels-and-whirls theorem states that if M is a 3-connected matroid and, for every element e, both the deletion and the contraction of e destroy 3-connectivity, then M is a wheel or a whirl. We prove some extensions of this theorem, one of which states that if M is 3-connected and has both a wheel and a whirl minor, then either M has only seven elements or there is some element the deletion or contraction of which maintains 3-connectivity and leaves a matroid with both a wheel and a whirl minor. © 1992.

When First Amendment Values And Competition Policy Collide: Resolving The Dilemma Of Mixed-Motive Boycotts, Kay P. Kindred

Faculty Publications

No abstract provided.

Judicial Matters, Neal Devins

Faculty Publications

No abstract provided.

Legal Breakdown: 40 Ways To Fix Our Legal System [Book Review], Margalynne J. Armstrong

Faculty Publications

No abstract provided.

Regulating Broadband Communication Networks, Allen S. Hammond Iv

Faculty Publications

No abstract provided.

Thermal Mathematical Modeling Of A Multicell Common Pressure Vessel Nickel-Hydrogen Battery, Junbom Kim, T. V. Nguyen, Ralph E. White

Faculty Publications

A two-dimensional and time-dependent thermal model of a multicell common pressure vessel (CPV) nickel-hydrogen battery was developed. A finite element solver called PDE/Protran was used to solve this model. The model was used to investigate the effects of various design parameters on the temperature profile within the cell. The results were used to help find a design that will yield an acceptable temperature gradient inside a multicell CPV nickel-hydrogen battery. Steady-state and unsteady-state cases with a constant heat generation rate and a time-dependent heat generation rate were solved.

Comparison Of Heat-Fin Materials And Design Of A Common-Pressure-Vessel Nickel-Hydrogen Battery, Junbom Kim, Ralph E. White

Faculty Publications

A two-dimensional, axisymmetric, and time-dependent thermal model was developed to study the temperature behavior of the cylindrically shaped common-pressure-vessel nickel-hydrogen cell. A differential-energy-balance equation was used as the governing equation. A finite-element software package called PDE/Protran was used to solve this model. Different materials such as copper, copper beryllium, silver, and sterling silver were compared as heat-fin materials. The heat-fin geometry (thickness and height) and spacing were tested to find a design that yielded an acceptable temperature gradient inside a nickel-hydrogen cell. Pulse heat-generation rates were tested and correlated with the time-dependent heat-generation cases.

Mathematical Modeling Of A Primary Zinc/Air Battery, Z. Mao, Ralph E. White

Faculty Publications

The mathematical model developed by Sunu and Bennion has been extended to include the separator, precipitation of both solid ZnO and K₂Zn(OH)₄, and the air electrode, and has been used to investigate the behavior of a primary Zn-Air battery with respect to battery design features. Predictions obtained from the model indicate that anode material utilizationis predominantly limited by depletion of the concentration of hydroxide ions. The effect of electrode thickness on anode material utilization is insignificant, whereas material loading per unit volume has a great effect on anode material utilization; a higher loading lowers both the …