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Full-Text Articles in Physical Sciences and Mathematics

Industrial Simulation With Animation, Edward T. Hammerand, Chung You Ho Dec 1985

Industrial Simulation With Animation, Edward T. Hammerand, Chung You Ho

Computer Science Technical Reports

This thesis examines and evaluates the new simulation language PCModel. Prior to the arrival of PCModel, simulation via computer typically resulted in pages of statistics compiled over the duration of the simulation. PCModel's approach is to simulate the model on the display before the user in real time. Additionally, user interaction is supported to allow changes to be made throughout the simulation run.

The evaluation of PCModel is accomplished through inspection of a pair of examples already simulated in a conventional simulation language. The examples show the relative strong and weak points of the language, as well as demonstrating how …


Investigation Of The Appropriateness Of Sensitized Luminescence To Determine Exciton Motion Parameters In Pure Molecular Crystals, Vasudev M. Kenkre, Paul Ernest Parris, Dankward B. Schmid Oct 1985

Investigation Of The Appropriateness Of Sensitized Luminescence To Determine Exciton Motion Parameters In Pure Molecular Crystals, Vasudev M. Kenkre, Paul Ernest Parris, Dankward B. Schmid

Physics Faculty Research & Creative Works

A wealth of experimental data has been collected over the years regarding the sensitized luminescence of molecular crystals. Indeed, such observations have played a primary role in attempts to characterize the dynamical aspects of exciton transport in these materials. Nonetheless, as has been noted previously, serious questions of interpretation remain concerning the relationship between primary experimental observables and microscopic parameters which govern exciton transport and capture. In the past these questions have led to an uncertainty, not always acknowledged, in the values of exciton diffusion constants reported in the literature. On the other hand, careful analysis of some recent experiments …


Electron Production In Proton Collisions: Total Cross Sections, M. Eugene Rudd, Yongki Kim, Don H. Madison, Jean W. Gallagher Oct 1985

Electron Production In Proton Collisions: Total Cross Sections, M. Eugene Rudd, Yongki Kim, Don H. Madison, Jean W. Gallagher

Physics Faculty Research & Creative Works

Existing data on the ionization of neutral atoms and molecules by proton impact are reviewed, and electron production cross-section data are collected. The three major experimental methods are discussed and possible sources of error identified. Some theoretical cross sections are discussed, and well-established methods of relating them to measured cross sections are reviewed. A mathematical equation is fitted to the weighted experimental data for each target, and these fits are adjusted to be consistent with appropriate theoretical calculations and with electron impact and photoionization data. Recommended values of total cross sections for proton-impact ionization are given.


Angular Differential Cross Sections For The Excitation Of 1¹S Helium To The 2¹S And 2¹P States By 25- To 100-Kev-Proton Impact, Thomas J. Kvale, Denver G. Seely, D. M. Blankenship, E. Redd, Timothy Gay, Mineo Kimura, Eduard P. Rille, Jerry Peacher, John T. Park Sep 1985

Angular Differential Cross Sections For The Excitation Of 1¹S Helium To The 2¹S And 2¹P States By 25- To 100-Kev-Proton Impact, Thomas J. Kvale, Denver G. Seely, D. M. Blankenship, E. Redd, Timothy Gay, Mineo Kimura, Eduard P. Rille, Jerry Peacher, John T. Park

Physics Faculty Research & Creative Works

Angular differential cross sections for the proton-impact excitation of ground-state helium (11S) to the 21S and 21P states have been measured for the first time in the energy range 25 to 100 keV with use of the energy-loss technique. The data indicate that, for very small scattering angles, at 25 keV the 21S differential cross section is greater than the 21P differential cross section. For impact energies greater than 50 keV, the 21P differential cross section clearly dominates over the 21S cross section in the very …


Time-Dependent Magnetic Structures Of The Superconducting Mixed Ternary System Ho(Rh₁₋ₓirₓ)₄B₄, Steven E. Lambert, M. Brian Maple, Oran Allan Pringle, Herbert A. Mook Sep 1985

Time-Dependent Magnetic Structures Of The Superconducting Mixed Ternary System Ho(Rh₁₋ₓirₓ)₄B₄, Steven E. Lambert, M. Brian Maple, Oran Allan Pringle, Herbert A. Mook

Physics Faculty Research & Creative Works

Magnetic structures have been determined by netron diffraction for several compositions in the superconducting mixed ternary system Ho(Rh1-xIrx)4B4. Two features previously reported to occur in the heat capacity for some compositions are shown to correspond to successive magnetic transitions. For x=0.30 and 0.45, neutron diffraction peaks for the lowest temperature structure develop over a timescale of many hours. The results are discussed in terms of magnetic frustration.


Method And Apparatus For Performing Hashing Operations Using Galois Field Multiplication, John L. Carter, George Markowsky, Mark N. Wegman Aug 1985

Method And Apparatus For Performing Hashing Operations Using Galois Field Multiplication, John L. Carter, George Markowsky, Mark N. Wegman

Computer Science Faculty Research & Creative Works

The invention comprises a method and apparatus for performing a hashing operation on an N bit number under control of a prespecified N bit hashing constant which comprises performing N/K finite field partial multiplications of the object to be hashed by the hashing constant, utilizing K logic and combinatorial circuits all of which operate in parallel to completely evaluate the number in N/K operations.

Another feature of the present invention is that the hashing constant loaded into the system may be changed at will with a resultant changing of the hashing characteristics to suit a particular class of objects to …


Low Temperature Tunneling Dynamics In Condensed Media, Paul Ernest Parris, Robert J. Silbey Aug 1985

Low Temperature Tunneling Dynamics In Condensed Media, Paul Ernest Parris, Robert J. Silbey

Physics Faculty Research & Creative Works

There has been considerable interest recently in the low temperature dynamics of condensed phase tunneling phenomena. In this paper we consider the interplay between quasiparticle transport and vibrational relaxation; the former taking place via tunneling in a double well potential, and the latter occurring due to interactions of the tunneling system with a harmonic bath. Taking the system-bath interactions to be linear in the bath coordinates, and explicitly allowing for a vibrationally excited well, we present a unified treatment of the weak and strong coupling regimes and obtain reduced equations of motion for the tunneling particle position operator. Solutions are …


A Monte Carlo Analysis Of The Mincycle Algorithm For Generating Minimal Perfect Hash Functions, Pao-Po Hou, Thomas J. Sager Jul 1985

A Monte Carlo Analysis Of The Mincycle Algorithm For Generating Minimal Perfect Hash Functions, Pao-Po Hou, Thomas J. Sager

Computer Science Technical Reports

In this paper, several minimal perfect hashing function generating methods are examined. One of them, the mincycle method by Sager is evaluated by the Monte Carlo method. The results are represented in graphs and tables.


A Parallel Branch And Bound Algorithm For Integer Linear Programming Models, Rochelle L. Boehning, Billy E. Gillett Jul 1985

A Parallel Branch And Bound Algorithm For Integer Linear Programming Models, Rochelle L. Boehning, Billy E. Gillett

Computer Science Technical Reports

A parallel branch and bound algorithm is developed for use with MIMD computers to study the efficiency of parallel processors on general integer linear programming problems. The Haldi and IBM test problems and a System Design model are used in the implementation of the algorithm. Initially the algorithm solves the Haldi and IBM test problems on a single processor computer which simulates a multiple processor computer. The algorithm is then implemented on the Denelcor HEP multiprocessor using two of the IBM problems to compare the results of the simulation to the results using an MIMD computer. Finally the algorithm is …


An Algorithm For Parallel Subsumption, Ralph M. Butler, Arlan R. Dekock May 1985

An Algorithm For Parallel Subsumption, Ralph M. Butler, Arlan R. Dekock

Computer Science Technical Reports

Many current automated theorem provers use a refutation procedure based on some version of the principle of resolution. These methods normally lead to the generation of large numbers of new clauses. Subsumption is a process that eliminates the superfluous clauses from the clause space, thus speeding up the proof. The research presented in this thesis is concerned with the design and implementation of a subsumption algorithm which exploits the parallelism provided by a multiprocessor. For portability, all coding is done in the programming language C. Monitors are used as the synchronization mechanism. Correct performance in both a multiprocessor and uniprocessor …


Small-Angle Neutron Scattering Of (Er₀.₈Ho₀.₂)Rh₄B₄, Oran Allan Pringle, Herbert A. Mook, M. Brian Maple Apr 1985

Small-Angle Neutron Scattering Of (Er₀.₈Ho₀.₂)Rh₄B₄, Oran Allan Pringle, Herbert A. Mook, M. Brian Maple

Physics Faculty Research & Creative Works

The (Er1-xHox)Rh4B4 pseudoternary alloy system has a minimum in the phase boundary between the superconducting and ferromagnetic phases near x=0.3. This minimum has been identified as due to the competing magnetic anisotropies of Er and Ho. It has also been suggested that there could be a Lifschitz point near the minimum. Using the 30-m SANS camera at the National Center for Small-Angle Scattering Research at ORNL, we have observed a peak in the SANS pattern for (Er 0.8Ho0.2)Rh4B4 at Q=0.065 Å-1. This peak appears for …


A Parallel Array Scanning Algorithm, Ralph M. Butler, Ralph W. Wilkerson Jan 1985

A Parallel Array Scanning Algorithm, Ralph M. Butler, Ralph W. Wilkerson

Computer Science Technical Reports

Suppose we are given a vector X of n real numbers and we want to find the maximum sum found in any contiguous subvector of X. In Jon Bentley's article [l] on algorithm design and technique, a simple vector scanning problem and a series of progressively more efficient algorithms to solve this problem were discussed in some detail. Clearly, any algorithm must visit each location of X at least once and consequently a lower bound on the running time for problem is 0(n), which is in fact attainable as Bentley’s paper illustrates. However, the original motivation for this problem was …


Ada: A New Programming Language., Daniel C. St. Clair Jan 1985

Ada: A New Programming Language., Daniel C. St. Clair

Mathematics and Statistics Faculty Research & Creative Works

In an attempt to control defense software costs while maintaining system reliability, the DOD (Department of Defense) has sponsored the development of a new programming language, called Ada. While Ada supports many of the features found in Fortran and Pascal, it has additional features making it easier and more reliable to use in large complex engineering software systems. Currently, the DOD is requiring that many new defense software systems be written in Ada. The author reviews the history of Ada's development and examines the primary constructs of the language. The philosophy behind Ada program design is reviewed by designing and …


Neutron-Diffraction Study Of The Magnetic Ordering In Ni(Ch₂Co₂Nh₂)₂ 2h₂O, Akifumi Onodera, Yorihiko Tsunoda, Nobuhiko Kunitomi, Oran Allan Pringle, Robert M. Nicklow, Ralph M. Moon Jan 1985

Neutron-Diffraction Study Of The Magnetic Ordering In Ni(Ch₂Co₂Nh₂)₂ 2h₂O, Akifumi Onodera, Yorihiko Tsunoda, Nobuhiko Kunitomi, Oran Allan Pringle, Robert M. Nicklow, Ralph M. Moon

Physics Faculty Research & Creative Works

The magnetic structure of Ni(CH2CO2NH2)2 2 H2O has been determined by the analysis of neutron-diffraction data from powder and single-crystal samples. Ni(CH2CO2NH2)2 2 H2O orders at a Néel temperature of 0.88 K. The magnetic structure consists of antiferromagnetically coupled layers having a canted ferromagnetic ordering within layers, with a moment of (2.33 ± 0.14)μB per Ni2+ ion. The magnetic unit cell is composed of two crystallographic unit cells, and contains four nickel atoms. The moment direction is not simply related …


Erratum: Normalized Line Shapes For Far-Wing Continuum Spectra: The Rb-Xe Satellite Band (Physical Review A(1985) 32, 5 (3150-3152)), Ronald James Bieniek Jan 1985

Erratum: Normalized Line Shapes For Far-Wing Continuum Spectra: The Rb-Xe Satellite Band (Physical Review A(1985) 32, 5 (3150-3152)), Ronald James Bieniek

Physics Faculty Research & Creative Works

Recent advances in experimental spectroscopy offer the promise of yielding much detailed information about molecular potentials and collisional interactions from a study of the light emitted or absorbed in the far wings of atomic lines. However, readily manipulable, accurate theoretical expressions and methods are needed to extract such knowledge. Straightforward formulas, based on the distorted-wave approximation, for the normalized emission intensity in the far wing of a pumped atomic line are given here. By normalizing theoretical spectra with respect to the strength of the atomic line, one obtains a convenient form for the analysis of experimental differential spectra that are …


Interobserver Variability In The Assessment Of Neurologic History And Examination In The Stroke Data Bank, David Shinar, Cynthia R. Gross, Jay P. Mohr, Louis R. Caplan, Thomas R. Price, Philip A. Wolf, Daniel B. Hier, Carlos S. Kase, Irene G. Fishman, Christine L. Wolf, Selma C. Kunitz Jan 1985

Interobserver Variability In The Assessment Of Neurologic History And Examination In The Stroke Data Bank, David Shinar, Cynthia R. Gross, Jay P. Mohr, Louis R. Caplan, Thomas R. Price, Philip A. Wolf, Daniel B. Hier, Carlos S. Kase, Irene G. Fishman, Christine L. Wolf, Selma C. Kunitz

Chemistry Faculty Research & Creative Works

Interobserver Reliability in Obtaining Neurologic Histories and Examinations Was Investigated among Neurologists Collaborating in the Stroke Data Bank (SDB). Seventeen In-Hospital Stroke Patients Were Examined by Six Neurologists Experienced in Stroke over the Course of Three Days. Patients Were Examined Twice a Day for Two Successive Days, with Each Patient Seen by Four Different Neurologists. Data Were Recorded on SDB Forms, According to Definitions and Procedures Established for the SDB. Percent Agreement and Κ Coefficients Were Calculated to Assess the Levels of Agreement for Each Item. Important Differences in Levels of Agreement Were Found among Items on Both Neurologic History …


Removal Of Colloidal Silica In Simulated Seawater By A Dynamic Multi-Short-Circuited Galvanic Cell, Jan E. Osterholm, Paul W. Kramer, Hlrotsugu K. Yasuda Jan 1985

Removal Of Colloidal Silica In Simulated Seawater By A Dynamic Multi-Short-Circuited Galvanic Cell, Jan E. Osterholm, Paul W. Kramer, Hlrotsugu K. Yasuda

Chemistry Faculty Research & Creative Works

A dynamic multi-short-circuited galvanic cell (MSCGC) with Pt-AI electrodes has been used to study the removal of colloidal silica from seawater as a pretreatment step for the desalination of seawater by use of reverse osmosis. The rate of silica removal is observed to be affected by the flow rate of the solution through the cell and the dissolved oxygen content of the solution as well as by the nature of the aluminum electrode surface and the number of contact points (short circuits) between the aluminum and platinum. The total silica content is reduced by 95 % by use of this …


Dynamic Structure Of N-Hexadecane Solubilized In A Nonionic Surfactant Bilayer Measured By Deuteron Magnetic Resonance, Anthony J.I. Ward, Stig Friberg, David W. Larsen, Shankar B. Rananavare Jan 1985

Dynamic Structure Of N-Hexadecane Solubilized In A Nonionic Surfactant Bilayer Measured By Deuteron Magnetic Resonance, Anthony J.I. Ward, Stig Friberg, David W. Larsen, Shankar B. Rananavare

Chemistry Faculty Research & Creative Works

A 2H NMR study was made of the order parameters of n-hexadecane molecules solubilized up to 55% (w/w) in a lyotropic lamellar liquid crystal of tetra ethylene glycol n-dodecyl ether and water for a range of compositions of varying water and hydrocarbon content. The NMR data supported a model with only a small amount of penetration of the hydrocarbon between the amphiphilic molecules and a rapid exchange on the 2H NMR time scale between the penetrated segments and the nonpenetrating molecules which latter are essentially isotropic. © 1985, American Chemical Society. All rights reserved.


Relative Fluorescence Efficiencies For The Dissociative Excitation Of Some Hg-Halides By N2(A ³Σu+), Laird D. Schearer Jan 1985

Relative Fluorescence Efficiencies For The Dissociative Excitation Of Some Hg-Halides By N2(A ³Σu+), Laird D. Schearer

Physics Faculty Research & Creative Works

No abstract provided.


Effects Of Iron Implantation On The Aqueous Corrosion Of Magnesium, S. Akavipat, Edward Boyd Hale, C. E. Habermann, P. L. Hagans Jan 1985

Effects Of Iron Implantation On The Aqueous Corrosion Of Magnesium, S. Akavipat, Edward Boyd Hale, C. E. Habermann, P. L. Hagans

Physics Faculty Research & Creative Works

The influence of the implantation of iron ions on the corrosion of magnesium and an AlZn-rich magnesium alloy (AZ91C) has been studied. Anodic polarization measurements in a dilute chloride-containing alkaline solution were used to evaluate corrosion resistance. A range of ion energies (50-180 keV) and doses (1016-2 x 1017 Fe+ ions cm-2) have been evaluated. Both the iron-implanted pure magnesium and the alloy AZ91C gave improved polarization measurements. A systematic positive shift of the open-circuit potential with increasing iron dose was found. In AZ91C at a dose of 1017 Fe+ ions cm-2, there was a + 0.6 V more noble …


Computerized Scanning Auger Microprobe, T. J. Sommerer, Edward Boyd Hale Jan 1985

Computerized Scanning Auger Microprobe, T. J. Sommerer, Edward Boyd Hale

Physics Faculty Research & Creative Works

An Auger spectrometer has been automated using a microcomputer. Fundamental considerations in the design and choice of the computerized system are presented and should be of general interest. The spectrometer was a Physical Electronics Ind. model 545 scanning Auger microprobe. The microcomputer chosen was a Southwest Technical Products 6809 computer system. Hardware details are discussed with emphasis on the four computer-spectrometer interface boards. These boards are (1) Auger energy control board, which sets the Auger detection energy with its 16 bit digital-to-analog converter (DAC); (2) read Auger signal board, which reads the Auger signal intensity with its 12 bit analog-to-digital …


Summary Abstract: Computerized Scanning Auger Microprobe, T. J. Sommerer, Edward Boyd Hale Jan 1985

Summary Abstract: Computerized Scanning Auger Microprobe, T. J. Sommerer, Edward Boyd Hale

Physics Faculty Research & Creative Works

No abstract provided.


Evidence For Uncorrelated Electron Capture And K-Shell Excitation In S13++He Collisions, J. A. Tanis, E. M. Bernstein, M. W. Clark, W. G. Graham, Robert H. Mcfarland, T. J. Morgan, B. M. Johnson, K. W. Jones, M. Meron Jan 1985

Evidence For Uncorrelated Electron Capture And K-Shell Excitation In S13++He Collisions, J. A. Tanis, E. M. Bernstein, M. W. Clark, W. G. Graham, Robert H. Mcfarland, T. J. Morgan, B. M. Johnson, K. W. Jones, M. Meron

Physics Faculty Research & Creative Works

Evidence is presented for a two-step process in ion-atom collisions in which two independent interactions occur in a single encounter. Measurements for 15200-MeVS13++He collisions indicate that uncorrelated projectile K-shell excitation and capture of a target electron occur in a single collision with one target atom. The results are in reasonable qualitative agreement with theoretical predictions of this two-step process. © 1985 The American Physical Society.


Spin-1 Exchange-Interaction Model Of Ferromagnetism, Harry A. Brown Jan 1985

Spin-1 Exchange-Interaction Model Of Ferromagnetism, Harry A. Brown

Physics Faculty Research & Creative Works

The spin-exchange operator for spin S=1 and a constant-coupling-like approximation are used to evaluate the thermodynamic properties of a system described by a two-spin Hamiltonian that includes dipole and quadrupole interactions. The dipole and quadrupole moments and the exchange energy are found as functions of temperature. There is a critical temperature, Tc, which depends on the coordination number of the lattice at which the system undergoes a second-order phase transition. Below Tc, both magnetic moments, simultaneously, take on nonzero values and have infinite derivatives there while the derivative of the exchange energy is discontinuous. Comparison is made with other results …


Electron Capture In Pseudo-Two-Electron Systems: Ar8++He, M. Kimura, Ronald E. Olson Jan 1985

Electron Capture In Pseudo-Two-Electron Systems: Ar8++He, M. Kimura, Ronald E. Olson

Physics Faculty Research & Creative Works

Molecular-structure calculations using the pseudopotential method have been performed on the (ArHe)8+ system. The cross section for single-electron capture in Ar8++He collisions was calculated for energies from 20 eV to 10 keV/amu. The perturbed-stationary-state method [M. Kimura, H. Sato, and R. E. Olson, Phys. Rev. A 28, 2085 (1983)], modified to include electron translation factors appropriate to two-electron systems, was used. The total cross section is relatively energy independent with a value of approximately 2.5x10-15 cm2. The n=4 level of Ar7+ is found to be preferentially populated, with the 4f level being dominant. © 1985 The …


Interaction Of Electric And Magnetic Charges: Addendum, I. Adawi Jan 1985

Interaction Of Electric And Magnetic Charges: Addendum, I. Adawi

Physics Faculty Research & Creative Works

The problem of a head-on collision between a spherically symmetric electric and magnetic charge is reconsidered. The assumption of the equality of the electric and magnetic forces made earlier is abandoned as it does not follow from the model. It is shown that the rotational angular momentum a charge acquires is determined by the amount of the angular momentum which the charge removes from the field by virtue of its extension. The interaction energy of each charge with the dipole it induces in the other charge is equal to the rotational energy of the charge itself. This results in simple …


Laser-Assisted Charge-Transfer Collisions: K++Na, Y. P. Hsu, M. Kimura, Ronald E. Olson Jan 1985

Laser-Assisted Charge-Transfer Collisions: K++Na, Y. P. Hsu, M. Kimura, Ronald E. Olson

Physics Faculty Research & Creative Works

A theory has been formulated to characterize charge-transfer collisions in the presence of an external laser field. The molecular-state-expansion method is used to describe the scattering process within the impact-parameter formalism. Electron translation factors are included in the molecular-state expansion so that the scattering wave function satisfies the correct boundary conditions. The theory is applied to the process K++NaK+Na+. In addition, we have made a detailed analysis of laser-assisted charge transfer for low-energy collisions. In this case, a Landau-Zener formula can be derived which shows that the cross section increases with decreasing incident energy. In general the laser coupling is …


Raman Studies Of Heavily Implanted, Dye-Laser-Annealed Gaas, H. D. Yao, A. Compaan, Edward Boyd Hale Jan 1985

Raman Studies Of Heavily Implanted, Dye-Laser-Annealed Gaas, H. D. Yao, A. Compaan, Edward Boyd Hale

Physics Faculty Research & Creative Works

Raman scattering is used to study the annealing behavior produced by 10 nsec, 565 nm dye laser pulses in high dose ion-implanted GaAs. Samples were prepared with Sn and Cd implantations of 2, 5, and 10 x 1015 cm2. The Raman spectra indicate that the threshold for epitaxial growth lies between 0.2 - 0.3 J cm2. Best carrier activation (∼ 2%), however, is achieved at ∼1.6 J cm2 for the Sn-implanted sample (n-type). For Cd implantation the electrical activation appears to be very high ({greater-than or approximate} 50%) for low pulse energies({less-than or approximate} 0.3 J cm2) but decreases for …


Faraday's Law Demonstration, Richard Sankovich Jan 1985

Faraday's Law Demonstration, Richard Sankovich

Physics Faculty Research & Creative Works

No abstract provided.


Electron Capture By Slow Alq+ Ions Colliding With Hydrogen, R. A. Phaneuf, M. Kimura, H. Sato, Ronald E. Olson Jan 1985

Electron Capture By Slow Alq+ Ions Colliding With Hydrogen, R. A. Phaneuf, M. Kimura, H. Sato, Ronald E. Olson

Physics Faculty Research & Creative Works

Total electron-capture cross sections have been measured for collisions of Alq+ (q=210) with H and H2 in the 20120-eV/amu energy range. The general trend of the cross sections for both H and H2 is an approximately linear increase with ionic charge state. The Al2++H and Al3++H systems were investigated theoretically using the molecular-orbital method with a pseudopotential to represent the Al3+ ion core. Coupled-channel calculations realize good agreement with experiment. An anomalously small cross section for Al2++H is attributed to the fact that of the 1 and 3 entrance channels, only the 1 …