Physical Sciences and Mathematics Commons^™

The Dependence On Zenith Angle Of The Strength Of 3-Meter Equatorial Electrojet Irregularities, H. M. Ierkic, Bela G. Fejer, D. T. Farley

Bela G. Fejer

Radar measurements in Peru were used to deduce the zenith angle dependence of the scattering cross section of plasma irregularities generated by instabilities in the equatorial electrojet. The irregularities probed by the 50 MHz Jicamarca radar had a wavelength of 3m. The cross section for the type 2 irregularities was isotropic in the plane perpendicular to the magnetic field, while the cross section for the stronger type 1 irregularities varied with zenith angle at a rate of approximately 0.3 dB/degree; the horizontally traveling waves were more than 100 times stronger than those traveling vertically.

An Experiment In Discovery, Daniel J. Steck

Physics Faculty Publications

No abstract provided.

Improving Physics Teaching, Robert Fuller

Robert G. Fuller Publications

I began this editorial with a desire to take up battle against the recent ills of physics teaching. I paused to peruse the AAPT reprint book, 50 Years on Teaching Physics, edited by Melba Phillips.

Trends In The Theory Of Atomic Photoionization, Anthony F. Starace

Anthony F. Starace Publications

For VUV photon energies, detailed theoretical understanding of the photoionization process has been achieved for the case of a single electron ionized from one of the outer subshells of a closed-shell atom. This understanding is based qualitatively upon a few properties of realistic atomic central potentials and quantitatively upon a few distinct types of electronic interactions known generically as particle-hole interactions. Current theoretical research is mainly directed at understanding a broader class of atomic photoionization phenomena involving, e.g., open-shell atoms, electronic interactions not of the particle-hole class, real two-electron processes, and external electric and magnetic fields.

Sound Absorption In N2-H2O Gas Mixtures At Elevated Temperatures, Roger W. Meredith

Physics Theses & Dissertations

Sound absorption measurements were conducted in N₂ -H₂O gas mixtures at 297, 343, and 387 Kelvin to determine the location of the vibrational relaxation peak of nitrogen on the frequency/pressure, (f/P), axis as a function of humidity and temperature. At low humidities the best fit of the data is to a linear relationship between (f/P)_max and humidity (h) yields a slope of 1 .84 X 10⁴ Hz/ atm mole fraction at all three temperatures. The slope is the same as that reported by Zuckerwar and Griffin (2.00 X 10⁴ Hz/atm mole fraction) but is …

High Resolution Laser Absorption Spectroscopy Of Ozone Near 1129.4 Cm-1, Lawrence N. Majorana

Physics Theses & Dissertations

A Beer's Law experiment was performed with a tunable laser to determine self broadened line shape parameters of one infrared absorption ozone line in the v1 band for ten pressures from 0.26 to 6.29 Torr at 285K. SO₂ line positions were used for wavelength calibration. Line shapes were iteratively fitted to the Voigt function at a Doppler width of 29.54 MHz (HWHM) resulting in values for the integrated line• strength, ( S), of (0.144 +/- 0.007 ) x ·10^-20 cm-1/molecule cm-2, line center frequency, (υ_ο) of 1129.426 cm-1 and the Lorentzian contributions to half width, (α …

Stopping Power Of Matter For Alpha Particles At Extreme Relativistic Energies, P.T. Leung, M. L. Rustgi, J. E. Turner

Physics Faculty Publications and Presentations

The stopping power of matter for alpha particles at extreme relativistic energies has been calculated by incorporating the charge form factor. A table is presented for aluminum, copper, and lead. It is found that at the highest energies considered, inclusion of form factor reduces the mass stopping power by about 6-8% in comparison with that predicted by Bethe's relativistic formula.

Thermal Decomposition Kinetics Of Asf5-Doped Polyacetylene In Vacuum, T. Inoue, J. E. Osterholm, H. Yasuda, L. L. Levenson

Physics Faculty Research & Creative Works

Electrical conductivity measurements, mass spectra of desorbing species, and ESCA surface analysis are reported for AsF5-doped polyacetylene heated between 50 and 130°C in vacuum. All measurements indicate first-order decomposition kinetics with activation energies between 13 and 20 kcal mole-1. Decomposition leads to the desorption of AsF3 and F2. Metallic arsenic remains in the polyacetylene as a decomposition by-product.

High Flux Beam Source Of Thermal Rare-Gas Metastable Atoms, D. W. Fahey, William F. Parks, Laird D. Schearer

Physics Faculty Research & Creative Works

A high-flux beam source has been constructed for the production of helium, neon and argon metastable atoms. The source is a DC electric discharge maintained in an expanding gas. A metastable flux of 3.5*1014, and 7.2*1013 atoms s-1 sr-1 has been achieved with most probable energies of 66, 72 and 74 meV for the helium, neon and argon sources, respectively. Time-of-flight measurements showed the widths of the respective velocity distributions to be 45%, 27% and 27%.

Dielectric Saturation In Dipolar Fluids. I. The Single-Molecule Distribution Function, John D. Ramshaw

Physics Faculty Publications and Presentations

The functional-derivative formalism is used to investigate the form of the equilibrium single-molecule distribution function n(1) in a finite fluid system of rigid polar molecules subjected to a strong external electric field that varies slowly with position. The investigation is based on the assumption that the long-range asymptotic behavior of the direct correlation function is independent of the external field, and is hence the same as in the unperturbed fluid. This assumption implies that n(1) has the form of a single-molecule Boltzmann factor in which the interaction energy is that of a deformable quasidipole with the local Lorentz electric field …

Electrostatic Tem Studies Of Magnetic Domains In Thin Iron Films, Hideaki Karamon

Dissertations and Theses

An electron microscope with electrostatic lenses was used for high resolution studies of magnetic domains in thin iron films.

Observation methods used to determine the directions of local magnetization in iron thin films were the Lorentz method and the Foucault method.

We studied how Bloch line-crosstie pairs and crosstie main walls behave in applied, in-plane magnetic fields. We found that crosstie main walls remain unchanged until crosstie density goes nearly to zero when the field is applied perpendicular to the main wall. A twisted type of domain appears where crossties disappear.

10 Kw Per Capita, Harry A. Brown

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

The rate of energy use in the U.S. is discussed. Possible savings in the principal areas of use are considered. The conclusion is that significant reductions could be made in five to ten years without new technology, but are not likely under present conditions.

Computed Cross Sections For Electron Transfer In Ba+ + Ba+ Collisions , Stanley J. Sramek, J.H. Macek, Gordon A. Gallup

Gordon Gallup Publications

Cross sections have been computed for the electron-transfer process Ba⁺+Ba⁺→Ba+Ba⁺⁺, for collision energies ranging from 25 to 500 keV. The straight-line classical-trajectory method has been used, with basis functions obtained by the multiconfiguration valence-bond method. Several numerical procedures applicable to future treatments of similar large systems were developed. The maximum cross-section value is found to be around 27π a₀² (2.4 × 10^-15 cm²), and occurs near collision energy 500 keV. The system's transient behavior has also been studied in detail during the collision, and it has been found that …

Orientation And Alignment Of The 3P 1P And 4D 1D Levels Of Neutral Helium, R. M. Schectman, R. D. Hight, S. T. Chen, L. J. Curtis, H. G. Berry, Timothy J. Gay, R. Deserio

Timothy J. Gay Publications

The alignment and orientation produced by the tilted-foil excitation of He was studied for a wide range of foil tilt angles and outgoing-atom velocities. In particular, two quantum states of different orbital angular momentum (3p ¹P and 4d ¹D) were investigated and the results were compared with a number of previously proposed models.

Debye–Hückel Theory For Particles Of Arbitrary Electrical Structure, John D. Ramshaw

Physics Faculty Publications and Presentations

Classical linearized Debye–Hückel theory is formulated for a finite fluid system, of arbitrary shape, composed of rigid particles with arbitrary internal electrical structure. The multipole description is eschewed in favor of the more basic description of a particle in terms of its charge density function. This function is left arbitrary, so the particles may be charged or neutral, polar or nonpolar, etc. The theory implies that the direct correlation function c(12)=−v(12)/k T, where v(12) is the Coulomb interaction energy between the charge densities of particles 1 and 2. In the case of uncharged polar …

Photoionization Cross Section For He In The Hyperspherical Coordinate Method, Donald L. Miller, Anthony F. Starace

Anthony F. Starace Publications

The hyperspherical coordinate method developed by Macek, Fano, Lin, and Klar to describe two-electron correlations is used for the first time to treat an atomic photoionization process. Using adiabatic approximations for both the initial and the final state, the cross section for the process He +γ +He⁺1s +e^– is calculated and is found to lie 1% higher than the revised experimental data of Samson at threshold, 4% lower at 1 Ryd above threshold, and 12% lower at 1.9 Ryd above threshold.

Electron-Density Studies Of Metal–Metal Bonds. I. The Deformation Density Of Ti2O3 At 295 K, M. G. Vincent, K. Yvon, A. Gruttner, J. Ashkenazi

Physics Articles and Papers

The electron-density distribution in Ti₂O₃ at room temperature has been determined from single-crystal X-ray diffraction data. The deformation maps show maxima of 0.15 e Å^-3 between the Ti atoms sharing a common face of O-atom octahedra, and maxima of 0.18 e Å^-3 between the O atoms and their four nearest Ti neighbours. These observations support the general view concerning the bonding in Ti₂O₃ and correlate well with the results of theoretical band-structure calculations. In particular, they confirm the existence of a metal-metal bond which is directed parallel to the ternary axis and …

Electron-Density Studies Of Metal-Metal Bonds. Ii. The Deformation Density Of V2O3, M. G. Vincent, K. Yvon, J. Ashkenazi

Physics Articles and Papers

The charge-density distribution in V₂O₃ differs from that in Ti₂O₃ mainly with respect to the deformation of the metal atoms. The V atoms show a positive deformation of up to 0.1 e Å^-3 perpendicular to c in a plane containing three nearest V-atom sites across the edges of the surrounding O-atom octhedra, and a negative deformation of up to 0.3 e Å^-3 parallel to c between the nearest V-atom site across the faces of the O-atom octahedra. These observations are in accordance with theoretical band-structure calculations and confirm the existence of an …

Bulk Magnetic Properties Of Magnetotactic Bacteria, C. R. Denham, R. P. Blakemore, Richard B. Frankel

Physics

Bulk magnetization measurements at room temperature of freeze dried magnetotactic bacterial cells, nonmagnetotactic bacterial cells, and extracted magnetosomes from magnetotactic cells are presented. The role of the magnetosome in the magnetotactic response of swimming cells is discussed.

Distorted Wave Born Approximation For Inelastic Collisions: Application To Electron Capture By Positrons From Hydrogen Atoms, Robin Shakeshaft, J. M. Wadehra

Physics and Astronomy Faculty Research Publications

We have re-examined the distorted-wave Born approximation for inelastic collisions. We find that the distortion in the relative motion of the collision partners cannot be neglected even for high-energy ion-atom collisions. Furthermore, if the distortion in the relative motion is not treated exactly, post-prior discrepancies will occur. We have applied the distorted-wave Born approximation, with distortion included through first order, to ground-state-to-ground-state electron capture by positrons from hydrogen atoms. The results are presented in this paper. We have also examined the nonrelativistic asymptotic behavior of the cross section for electron capture from hydrogen by positrons incident with a speed v∼∞. …

Heavy Ion Beam Model For Radiobiology, Rose Ann Roth, Robert Katz

Robert Katz Publications

An ad hoc model of energetic heavy ion beams, including secondary and tertiary particles, has been constructed for predicting radiobiological experiments. While the beam model is relatively primitive, it yields depth-dose and depth-radiobiological calculations in good agreement with experiment upstream of the Bragg peak. Beyond the peak, the model is somewhat coarse grained and seems to underestimate low-LET fragment production. These defects can be repaired at some cost in computer time. Presently a complete set of depth-dose and radiobiological results (RBE, OER, aerobic and hypoxic survival) is obtained in 4–8 min, for a single beam, at a cost of $10. …

Large Momentum Transfer Limit Of Some Matrix Elements, J. M. Wadehra, Larry Spruch

Physics and Astronomy Faculty Research Publications

The matrix element εfi(K), or ε, that appears in the study of elastic and inelastic electron-atom scattering from an initial state i to a final state f in the first Born approximation depends explicitly on the momentum transfer ℏK⃗ . The uncertainty in the value of the calculated cross sections arises not only from the application of the Born approximation but also from the approximate nature of the wave functions used. For the 1 S1−2 P1 transition in helium, we present an analytic expression in terms of the 1 S1 and 2 P1 wave functions for the leading coefficient C1 …

An Empirical Model Of Quiet Dayionospheric Electric Fields Of Middle And Low Latitudes, A. D. Richmond, M. Blanc, B. A. Emery, R. H. Wand, Bela G. Fejer, R. F. Woodland, S. Ganguly, P. Amyenc, R. A. Behnke, C. Calderon, J. V. Evans

Bela G. Fejer

Seasonally averaged quiet-day F region ionospheric E × B drift observations from the Millstone Hill, St. Santin, Arecibo, and Jicamarca incoherent scatter radars are used to produce a model of the middle and low-latitude electric field for solar minimum conditions. A function similar to an electrostatic potential is fitted to the data to provide model values continuous in latitude, longitude, time of day, and day of the year. This model is intended to serve as a reference standard for applications requiring global knowledge of the mean electric field or requiring information at some location removed from the observing radars. This …

Frequency-Dependent Conductivity In Nbse3, G. Gruner, L. C. Tippie, Jeff Sanny, W. G. Clark, N. P. Ong

Physics Faculty Works

The observation of a frequency-dependent conductivity (σ) and dielectric constant (ε) in NbSe₃ is reported. In both charge-density-wave phases a strong frequency dependence and huge dielectric constant are observed below 100 MHz, with greatest effects observed at 42 K. The conductivity σ increases smoothly from the dc value to the high-frequency (f=100 MHz) limit; this increase is accompanied by the reduction of ε. A resistance-capacitance network model is suggested to account for the observed frequency dependence.

22nd Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Abstracts and meeting program from the 22nd annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, August 10-14, 1980.

A Study Of The Target Thickness Effect For Chlorine On Germanium From 25 To 49.5 Mev, James Robert Slusser

Masters Theses

No abstract provided.

Development Of A System For Water Quality Analysis Using Particle Induced X-Ray Emission, James Albert Andrus

Masters Theses

Particle induced x-ray emission (PIXE) has been in use for several years at Western's accelerator laboratory. Its primary purpose has been to provide trace element analysis of various types of solid samples. The analysis of water samples has not been done because of problems involving target preparation for the accelerator. A process called vapor filtration, developed at Purdue University, allows adequate sample preparation for the accelerator. This process is being adapted for use here at WMU. When completely operational, this system will give the WMU accelerator program the additional capability of performing water quality analyses to concentrations of parts per …

Analysis Of Differential Corrosion On High-Silicon Steel Laminations, Sompob Tingthanathikul

Masters Theses & Specialist Projects

The Cutler-Hammer plant in Bowling Green, Kentucky,manufactures laminated steel armatures for electrical starters (large relays) on which corrosion occurs only in some regions. The manufacturing process includes a heat treatment step from which the laminations emerge with a non-uniform surface appearance.

Laminations from corroded regions of an armature have red oxide (Fe₂0^₃) on the edges, while the sides have a black coating of partly-burned cutting-machine oil residue. The purpose of the project was to investigate the mechanisms of this corrosion and why it does not occur uniformly and to suggest practical solutions for the plant.

Emission …

South-Seeking Magnetotactic Bacteria In The Southern Hemisphere, R. P. Blakemore, Richard B. Frankel, Ad. J. Kalmijn

Physics

Several species of aquatic bacteria which orient in the Earth's magnetic field and swim along magnetic field lines in a preferred direction (magnetotaxis) have been observed in marine and freshwater sediments of the Northern Hemisphere^1,2. Their orientation is due to one or more intracytoplasmic chains of single-domain magnetite particles³. These linearly arranged particles impart a net magnetic dipole moment to the bacterium, parallel to the axis of motility. Northern Hemisphere magnetotactic bacteria with unidirectional motility swim consistently in the direction of the magnetic field, that is, to the geomagnetic North^1,2,4. This implies that their …

Theoretical Potential Curves For Excited States Of Arh And The Rate Of Collisional Quenching Of Metastable Ar By H, R.L. Vance, Gordon A. Gallup

Gordon Gallup Publications

Energy curves for the ground state and the first seven excited states of ArH have been calculated using the multiconfiguration valence bond (MCVB) method. Important features of the excited curves include two distinct avoided crossings between the lowest Ar*H and the highest ArH* potential energy curves. Using these curves we have made a theoretical analysis of quenching of metastable Ar by collision with H at room temperature. Application of the Massey criterion indicates that the separation of the potential curves in the region of the crossing and the acceleration produced by the fall of the reactant channel potential curve from …