Physical Sciences and Mathematics Commons^™

Racial Differences In The Distribution Of Posterior Circulation Occlusive Disease, Philip B. Gorelick, Louis R. Caplan, Daniel B. Hier, Dushyant Patel, Patricia Langenberg, Michael S. Pessin, Jose Biller, David Kornack

Chemistry Faculty Research & Creative Works

We Compared Clinical and Arteriographic Features in 27 White and 24 Black Patients with Symptomatic Posterior Circulation Occlusive Disease. the Degree of Arterial Stenosis Was Measured Independently by Two Examiners at 12 Sites within the Vertebrobasilar Territory. Racial Comparisons Were Made based Upon the Distribution of Extra- and Intracranial Occlusive Lesions and Symptomatic Sites of the Lesions. White Patients Had Significantly More Angina Pectoris, More Lesions of the Origin of the Left Vertebral Artery and More High-Grade Lesions of the Extracranial Vertebral Arteries. Black Patients Had Significantly Higher Mean Diastolic Blood Pressure, More Diabetes Mellitus, More Lesions of the Distal …

Charge Transfer Of Hydrogen Ions And Atoms In Metal Vapors, T. J. Morgan, Ronald E. Olson, A. S. Schlachter, J. W. Gallagher

Physics Faculty Research & Creative Works

Cross sections and equilibrium fractions for energetic H+, H−, and H0 in collisions with metal vapor targets have been compiled and evaluated. Both experimental and theoretical results are reported. Sources of errors are discussed, and recommended values for the data are presented. © 1985, American Institute of Physics for the National Institute of Standards and Technology. All rights reserved.

Plasma Polymerization Investigated By The Substrate Temperature Dependence., H. Yasuda, Cheng Wang

Chemistry Faculty Research & Creative Works

In the reported experiments, plasma polymerization of tetrafluoroethylene (TFE), perfluoro-2-butyl-tetrahydrofuran (PFBTHF), ethylene, and styrene were investigated in various combinations of monomer flow rates and discharge wattages for the substrate temperature range of minus 50 to 80 degree C. The polymer deposition rates can be generally expressed by k//o equals Ae** minus **b**t, where k//o is the specific deposition rate given by k//o equals (deposition rate)/(mass flow rate of monomer), A is the preexponential factor representing the extrapolated value of k//o at zero absolute temperature, and b is the temperature-dependence coefficient. It was found that the value of b is not …

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 …

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

Doctoral Dissertations

"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 …

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.

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 …

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.

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 …

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 …

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 …

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 …

Industrial Simulation With Animation, Edward T. Hammerand

Masters Theses

"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 …

Carbonate Facies Of The Kimmswick Limestone (Trenton/Galena) In Southwestern Illinois : Their Relations As Oil Reservoirs And Traps, Gregory A. Crews

Masters Theses

"Four potentially productive oil horizons have been identified in the Kimmswick Limestone (Trenton/Galena), Ordovician of southwestern Illinois. Four non-porous caprock zones and four porous horizons were identified and informally named after corresponding members of the Dunleith Formation (Illinois State Geological Survey classification). The porous horizons generally consist of coarse-grained, fossiliferous limestone, which is overlain by finer grained, spar-cemented, impermeable limestone.

In order of production potential, the horizons are the upper Moredock, lower Moredock, Beecher-St. James (lowermost stratigraphic unit), and New London (uppermost stratigraphic unit). Porosity in the upper Moredock horizon is relatively consistent throughout the study area, as determined by …

Survey Of Routing Algorithms For Computer Networks, Lu Yu, Thomas J. Sager

Computer Science Technical Reports

This thesis gives a general discussion of routing for computer networks, followed by an overview of a number of typical routing algorithms used or reported in the past few years. Attention is mainly focused on distributed adaptive routing algorithms for packet switching (or message switching) networks. Algorithms for major commercial networks (or network architectures) are reviewed as well, for the convenience of comparison.

Increased Optical Damage Resistance In Lithium Niobate, D. A. Bryan, Robert Gerson, H. E. Tomaschke

Physics Faculty Research & Creative Works

We have confirmed greatly improved resistance to photorefractive damage in compositions of lithium niobate containing 4.5 at. % MgO or more. Holographic diffraction measurements of photorefraction demonstrated that the improved performance is due to a hundredfold increase in the photoconductivity, rather than a decrease in the Glass current. The diffraction efficiency shows an Arrhenius dependence on temperature, with an activation energy of 0.1 eV for the damage-resistant compositions, compared with 0.5 eV for undoped or low-magnesium compositions. The damage-resistant compositions are distinguished by a 2.83-μm absorption line instead of the usual 2.87-μm line due to the OH-stretch vibration.

Threshold Effect In Mg-Doped Lithium Niobate, K. L. Sweeney, L. E. Halliburton, D. A. Bryan, R. R. Rice, Robert Gerson, H. E. Tomaschke

Physics Faculty Research & Creative Works

Optical absorption spectra were obtained after reducing (i.e., vacuum annealing) a series of LiNbO3 crystals grown from melts having various Mg concentrations and Li/Nb ratios. A band peaking at 500 nm, and assigned to oxygen vacancies containing two electrons, was the only absorption present in one set of crystals following reduction. In contrast, two overlapping bands peaking near 1200 and 760 nm were present in the other set of crystals immediately after the reduction. The 1200-nm band is assigned to a previously unreported electron trap and the 760-nm band to oxygen vacancies containing only one electron. These data are interpreted …

Microprocessor-Based Pressure Controller, E. Redd, John T. Park

Physics Faculty Research & Creative Works

A device for automatic control of pressure in an ion-atom scattering experiment has been constructed. The system was modeled to achieve the minimum time for transition from one pressure to another. The pressure controller "learns" the system response and iterates the parameters used in "profiling" the valve voltage to reduce the transition time. The device has been used with two different scattering chambers and has worked well with both.

Evaluation Of Plasma Polymers Of Silanes As Adhesion Promoters For Organic Paint, Y. Matsuda, H. Yasuda

Chemistry Faculty Research & Creative Works

Plasma-polymerized coatings were prepared in a bell-jar-type reactor equipped with a magnetron system behind parallel aluminum electrodes using an a.c. source of frequency 10 kHz. Tetramethoxysilane, dimethyldimethoxysilane and hexamethyldisilane were used as monomers. Alkyd paint was coated on titanium plates onto which plasma polymer films had been deposited, to investigate the characteristics of the plasma-deposited films as adhesion promoters. The relationship between the adhesion strength for the paint and the conditions for the plasma polymerization was studied. The properties of the plasma polymers are dependent on the conditions of plasma polymerization manifested by two domains, namely the energy-deficient and the …

Preparation Of Gas Separation Membranes By Plasma Polymerization With Fluoro Compounds, H. Nomura, P. W. Kramer, H. Yasuda

Chemistry Faculty Research & Creative Works

Plasma polymerization coatings were applied for the preparation of gas separation membranes. Mainly fluoro compounds were used as coating materials. The membranes showed good separation characteristics with high flux for gaseous systems. The plasma polymerization composite parameter given by W/FM plays an important role in obtaining excellent separation characteristics. The correlation between the conversion rate DR/FM, where DR is the deposition rate of plasma polymer, and W/FM is useful to consider the plasma polymer character under the different plasma polymerization conditions (discharge power W and monomer flow rate F). The proper conditions for membrane preparation lie in the intermediate region …

A Simple Method For Organizing Nearly Optimal Binary Search Trees, Joy L. Henderson, John R. Metzner

Computer Science Technical Reports

Improving the efficiency of retrieving information concerns users of computer systems involved in many applications- One way of addressing this concern is to organize a sorted sequence into a binary search tree. Knuth's Algorithm K is a bottom-up organization algorithm that always constructs a binary tree which minimizes average search time. However, the cost of executing Algorithm K is prohibitive for a large tree. The aim of this work is to find a less costly method of organizing sorted sequences into nearly-optimal binary search trees.

We present a top-down organization method which yields better average search times than top-down methods …

The Design And Implementation Of The Programming Language Natural, Alan L. Sparks, Thomas J. Sager, Arlan R. Dekock

Computer Science Technical Reports

This paper reports progress on the development of the programming language Natural, currently under design by Dr. Thomas J. Sager at the University of Missouri--Rolla. Natural is a very high-level language with a mathematical flavor, and includes several concepts relatively uncommon in programming language design.

The text also discusses an implementation on the IBM Personal Computer of Mini-Natural, a subset of Natural, and presents examples of programs written in Mini-Natural.

Angular Differential And Total Cross Sections For The Excitation Of Atomic Hydrogen To Its N=2 Level By 25-150-Kev Hydrogen Molecular Ions, Jerry Peacher, Paul J. Martin, Denver G. Seely, Judith E. Aldag, Thomas J. Kvale, E. Redd, D. M. Blankenship, V. C. Sutcliffe, John T. Park

Physics Faculty Research & Creative Works

Experimentally and theoretically determined differential and total cross sections are reported for excitation of atomic hydrogen to its n=2 level by 25-150-keV hydrogen molecular ions. The differential cross sections decrease 3-4 orders of magnitude over the measured center-of-mass scattering-angular range from 0 to 4.5 mrad. The results of a first Born approximation and two other theoretical calculations based upon the Glauber approximation are presented and compared with the experimental results. Both calculations based on the Glauber approximation agree fairly well with the experimental results. The Born approximation agrees moderately well with the experimental results at the very small scattering angles …

A Focus Of Attention Algorithm For Expert Systems, Kevin W. Whiting, Arlan R. Dekock, John Bruce Prater

Computer Science Technical Reports

This research is primarily concerned with increasing the performance of expert systems. A refined focus of attention strategy and its affect on performance are discussed. Early expert systems used a brute force approach to process the knowledge base. Each production rule in the knowledge base was evaluated each cycle. More recently, processing efficiency has been increased by focusing the attention of the inference engine on a subset of the rules by "filtering" for further testing, only rules that could possibly fire given the current content of the context base. Focus of attention as developed in this research increases performance over …

Color Computer Graphics As Applied To Introductory Calculus Instruction, Kathy B. Windhorst, Ralph E. Lee

Computer Science Technical Reports

The use of computer graphics to support and enhance the presentation of introductory calculus concepts is described.

Computer graphics provides more accurate graph sketching, consistent presentations and the ability to develop mathematical models incrementally. The addition of extensive use of color aids even more, adding contrast, color keying, dimensionality, and interest to an illustration.

Ten lessons have been designed, developed, and evaluated. They employ a set of subroutines which interface to the NBC APC microcomputer graphics software. These lessons as developed and evaluated may be used interactively in the classroom or by individuals, or noninteractively in the classroom by the …

Ciegen: A System For Testing Knowledge Base Compilation Heuristics On A Microcomputer, Jayne D. Ward, Billy E. Gillett, Arlan R. Dekock

Computer Science Technical Reports

The expert system has proven itself to be a valuable aid in diagnosing and treating problems in domains requiring expertise. The commercial world has been alerted to this fact and the thrust is to make the expert system portable and available on small computers.

The goal of this research has been to lay the groundwork for a domain independent expert system builder on a microcomputer. The result of this effort was CIEGEN, a system consisting of a rule compiler, inference engine, and rule generator developed on the IBM PC. It is domain independent, responsible for transforming a knowledge base of …

Full Second-Order Distorted-Wave Calculation Without Approximations For Atomic Excitation By Electron Impact, Don H. Madison

Physics Faculty Research & Creative Works

A new technique has been developed for evaluating second-order distorted-wave amplitudes for atomic excitation without making any approximations. By this technique, second-order amplitudes with arbitrary distorted waves and arbitrary Green's functions in the interaction can be evaluated with comparable difficulty. The utility of the method is demonstrated through a practical calculation of the second-order distorted-wave approximation for electron excitation of the 2p state of hydrogen.

A Graphical Representation Of An Executing Program, Sherry A. Lile, Arlan R. Dekock, John Bruce Prater, Darrow Finch Dawson

Computer Science Technical Reports

This thesis describes the rationale for a computer program used as a teaching aid, as well as, the design, development, and implementation of that computer program. The program is a prototype that displays, line by line, a graphical depiction of a BASIC program being executed. Icons are used to represent FOR-NEXT loops, the contents of variables, I/O, and other programming elements. The internal logic associated with the Arithmetic-Logic Unit is also represented. The purpose is to produce an environment where the student may visualize the processes occurring in memory by viewing a symbolic portrayal of an executing program. The example …

The Optimal Trajectory Modelling Of Robot Manipulators, Mary Claire Miller, Chung You Ho, Arlan R. Dekock

Computer Science Technical Reports

Greater robot capability can be achieved through the use of robot manipulator control systems. Crucial to the success of these control systems is the optimal trajectory modelling of the path traced by the end- effector. To create this optimal path the utilization of B-Spline curve functions will be investigated, and compared to Cubic Spline curve functions.

An Experimental Study Of The Effects Of Modularity On Resource Consumption In Software Development, Alan D. Christiansen, Arlan R. Dekock, John Bruce Prater

Computer Science Technical Reports

Many authors have encouraged the use of modular programming techniques in software development. In fact, there is almost total agreement within industrial and academic circles that modularity is a desirable feature of any software package. Unfortunately, the desirability of modular design is almost always voiced without support from experimental evidence.

This paper consists of an experiment comparing the resource consumption of programmers based on the modularity practices employed during the design and programming phases of software development. The experiment tests the effectiveness of modularity in reducing psychological complexity of software.

The results of the research show that in some cases …