Physical Sciences and Mathematics Commons^™

Identification Of Cosmic Particles 3695 Mev/C2 And 3105 Mev/C2, Frank H. Meyer, Ronald W. Satz

Journal of the Minnesota Academy of Science

No abstract provided.

Sporadic Mass Ejection In Red Supergiants, Menas Kafatos, A. G. Michalitsianos

Mathematics, Physics, and Computer Science Faculty Articles and Research

We have applied a general mechanism first proposed by J. A. Burke to red supergiants for determining the spin-down rate and angular momentum loss of rotating stars. This model relies principally on sporadic mass ejection, which is assumed to be the result of turbulent elements accelerating material in cool supergiant.atmospheres. Mass is preferentially expelled in the forward direction of rotation, resulting in a rapid loss of angular momentum on time scales of 1Q^4-10^6 years in the supergiant evolutionary phase. Such rotational breaking will occur if the turbulent elements have characteristic sizes a few percent of the stellar radius, and rms …

Penrose Pair Production As A Power Source Of Quasars And Active Galactic Nuclei, Menas Kafatos, D. Leiter

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper we propose a new mechanism, Penrose pair production in massive, canonical (with a/M = 0.998) Kerr black holes, as a power source in quasars, Seyfert galaxies, radio galaxies, and BL Lac objects (i.e., what one usually refers to as active nuclei). As a working hypothesis, we postulate that massive (10^8 M0 or around this value) Kerr black holes reside in the centers of these objects. We also postulate that an accretion disk is formed. In a variety of models, hot, inner disks are expected. If the temperature is sufficiently high-as, for example, in the two-temperature model-then MeV …

Chemical Vapor Deposited Molybdenum Films For Use In Photothermal Conversion, David D. Allred, G. E. Carver, B. O. Seraphin

Faculty Publications

High infrared reflectance, coupled with higher solar absorptance, is required for efficient photothermal conversion. Converters can be fabricated by depositing an absorber on a highly reflecting metal. The absorber functions in the visible, yet becomes transparent in the near infrared, allowing the metal to suppress the thermal emittance. Economic considerations demand the use of thin films, rather than bulk materials. The thin film reflector must be capable of withstanding high temperatures of operation. Compatibility of the reflector with the substrate below, and the absorber above, is required for long-time service. Highly reflective silver films suffer reflectance losses by agglomeration, and …

Chemical Vapor Deposited Amorphous Silicon For Use In Photothermal Conversion, David D. Allred, D. C. Booth, M. Janai, G. Weiser, B. O. Seraphin

Faculty Publications

Efficient photothermal conversion requires surfaces of high solar absorptance and low thermal emittance. This can be accomplished by the tandem action of a good infrared reflector overlaid by a film of sufficient solar absorptance that is transparent in the infrared. Crystalline silicon is a suitable candidate for the absorber layer. Its indirect band gap, however, results in a shallow absorption edge that extends to far into the visible. In contrast, the absorption edge of amorphous silicon is steeper and located farther into the infrared, resulting in a larger solar absorptance. We report on the fabrication of amorphous silicon absorbers by …

"Needed Social Innovations (Lecture 2)", John Rader Platt

Special Collections: Oregon Public Speakers

No abstract provided.

"Space Settlements", John Billingham

Special Collections: Oregon Public Speakers

No abstract provided.

Recipe For A Moon, Edwin J. Geels

Pro Rege

No abstract provided.

Energy And Angular Distribution Of Neutrons From Proton-Proton Inelastic Scattering At 800 Mev, Ted Dean Rupp

Physics & Astronomy ETDs

The neutron energy spectra from the reaction p + p → n + p + π⁺ for an incident proton energy of 800 MeV was measured for all phase space. ++ The channels were dominated by △⁺⁺. (1232) resonance and had a total cross section of 16 ± 1.5 mb. Also, the data demonstrated the dominance of Sand P waves. The experimental results were compared to isobar, phase space and a one pion exchange model. The isobar and phase space models failed to predict the experimental results; however, the one pion exchange model fit the data for …

Polynomial And Rational Fraction Representations Of A Diatomic Molecular Potential, Paul R. Findley

Physics & Astronomy ETDs

A method is presented for approximating a diatomic molecular vibrational potential by fitting to modified forms of the potential. Power's numerical Born-Oppenheimer potential for the H₂⁺ electronic ground state is the potential used in this thesis. The modification procedure is to multiply the potential by various powers of the internuclear separation. This removes the troublesome Coulomb pole at zero internuclear separation. Graphs of the modified forms are presented. Polynomials were fitted directly to the potential, to the modified forms, and to the pure electronic energy. Comparisons are made among the various representations of the potential obtained from the …

Penrose Pair Production In Massive, Extreme Kerr Black Holes, D. Leiter, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

We show that in the case of very massive (M > 108 M0 ) Kerr black holes with extreme ranges of angular momentum 1 ≥ a/M > 0.998, the possibility of photon-induced Penrose pair production (PPP) in the ergosphere is very plausible. The pairs that escape the ergosphere are very high energy and on the order of the GeV rest mass of the Penrose accreted protons which participate in the photon-induced pair production process. Application of this model to the case of quasistellar objects (QSOs) is shown to lead to reasonable predictions about their masses, lifetimes, and luminosities. The physical mechanism is …

Mass Loss And Oh Maser Emission From Mira Variables, A. G. Michalitsianos, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

We have estimated the mass, radius, and luminosity of 26 Mira variables that are known OH sources of radio emission at 1612 MHz. The time-independent solution of Salpeter's stellar wind equation and a period-density relation are used to solve for basic stellar parameters, with the aid of the terminal expansion velocity of the OH maser cloud. Masses obtained from these calculations are consistent with other estimated values for masses of Mira variables. Good agreement is obtained when comparing the rate of mass loss as determined from Reimers's semiempirical relation to estimates of the mass loss rate as deduced from theoretical …

The Central, Compact Source In The Cygnus A Galaxy, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Single, optically thin, component models as well as double, optically thick at low frequencies, component models have been examined in trying to explain the central source in the nucleus of Cygnus A. In the course of exploring those models, it is found that this compact radio source may be quite similar to other compact and variable sources in Seyfert galaxies and quasars. Double component models generally do better because they fit the X-rays, and there is a good chance that the X-rays arise in the central source; these models can naturally explain variability which may already have been detected in …

Cygnus A At 99 Ghz: Observations Of The Three Principal Components And The Interpretation Of The Central Source, R. W. Hobbs, S. P. Maran, Menas Kafatos, L. W. Brown

Mathematics, Physics, and Computer Science Faculty Articles and Research

The three principal emission components of Cygnus A have been observed at 99 GHz, the highest frequency at which radio measurements of this source have been accomplished. The observations show no definite indication of a high-frequency cutoff in the spectrum of the compact central component, which perhaps may be attributed to an optically thin synchrotron source that peaks at a frequency of several hundred GHz.

Precipitation Phenomena In Antimony-Implanted Aluminium, Richard Allen Kant

Physics & Astronomy ETDs

An experimental and theoretical study of the influence of temperature flux, and fluence on the formation and evolution of compounds formed by ion implantation has been conducted. Transmission electron microscopy was used to determine the size distribution of AJSb precipitates resulting from implanting single crystal A1 with Sb. In addition, the role of ion damage was investigated using both Ar and Al bombardment. These experiments show that for samples which initially contain no Sb, the number density of pre• cipitates decreases with increasing fluence and temperature, and with decreasing flux.

Measurement Of The H- Photodetachment Cross Section In The Continuum Region From 1.5 To 10.5 Ev, Mohammad Hassan Sharifian-Attar

Physics & Astronomy ETDs

We have measured the H photodetachment cross section in the photon energy range from 1.5 to 10.5 eV, using a colliding beam method. The H beam with an energy of 800 MeV, at Los Alamos Linear Accelerator, was intersected by a nitrogen laser beam with a photon energy of 3 .678 eV in the lab frame. We changed the energy of the pho"ton in the H rest frame, through the Doppler effect, by varying the angle between the laser and the H beams. The magnitude of the Doppler shift was enough to cover the entire range from 1.5 to 10.5 …

Neutron-Proton Elastic Scattering At 790 Mev, Roger Daniel Carlini

Physics & Astronomy ETDs

The forward n-p differential cross-section is measured at 790 Mev from 9.5 to 60. degrees in the center of mass. The systematic errors are less than 4.0%. The differential cross-section is parameterized by the function dσ/dΩ = A e^bt, where t is the momentum transfer between the incoming and outgoing neutrons in (GeV/C)², and A and b are constants having the values A= 9.757±.069, b= 5.052±.045. With 36 data points the x² is 55. The magnitude of the ratio of the real to imaginary part of the forward scattering amplitude is found to be .3501±.14.

Astronomy And The Bible: Joshua's Long Day, Joel W. Block

Physics Faculty Publications

The Bible has served as a multipurpose text for thousands of years. However, the Bible has been ignored in the area of astronomy. Several teaching points can be demonstrated using the Bible stories and modern astronomical principles.

Convection In Pulsating Stars, Michael John Robert Costello

Physics & Astronomy ETDs

Stellar models using mixing length convection in a linear calculation show a red edge to the instability strip. The models are of a 6 solar mass, 1 x 10 ergs/sec luminos­ity, King 4A composition, cepheid variable star, for various values of effective temperature, Te, and mixing length parameter, a. Results are obtained with an assumed instantaneous adjustment of the convective flux to changes in the local stellar conditions. Calculations of the convective time de­lay show it to be small compared to the period, under the assumption that the convective time delay is due solely to the inertia of convective bubbles. …

The Use Of Nuclear Reactions And Sims For Quantitative Depth Profiling Of Hydrogen In Amorphous Silicon, David D. Allred, G. J. Clark, C. W. White, B. R. Appleton, C. W. Magee, D. E. Carlson

Faculty Publications

Depth profiles for hydrogen in amorphous silicon have been determined by the use of resonant nuclear reactions [1H(15N,αγ)12C and 1H(19F,αγ)16O] and by secondary ion mass spectroscopy (SIMS). Independent calibration procedures were used for the two techniques. Measurements were made on the same amorphous silicon film to provide a direct comparison of the two hydrogen analysis techniques. The hydrogen concentration in the bulk of the film was determined to be about 9 at % H. The SIMS results agree with the resonant nuclear reaction results to within 10%, which demonstrates that quantitative hydrogen depth profiles can be obtained by SIMS analysis …

Heights Of Formation For Certain Solar Spectral Lines, Erik J. Schwendeman

Physics & Astronomy ETDs

Heights of formation are calculated for several of the solar spectral lines studied by the National Aeronautics and Space Administration - Goddard Space Flight Center (NASA-GSFC) New Mexico Solar Station at Sacramento Peak Observatory. These lines are Ca II H, K, 8498 Å and 8542 Å, MgI b₁, NaI D₁ and D₂ and Sil 4103 Å. I calculate the heights of formation for each of these lines along with upper and lower confidence limits representing the height region where 90% of the total intensity of the line is formed in the solar photosphere and chromosphere. The …

A Covariant Approach To Wave Equations In General Relativity, Alan L. Dudley

Physics & Astronomy ETDs

A formalism for the manipulation of tensors in both real and complex spacetimes is introduced, which utilizes the irreducible representations of the Lorentz group to substantially simplify certain general relativistic calculations. The notation is completely covariant and is most effective for massless field calculations. Results emerge which eliminate the majority of the algebraic burden of the traditional Newman­Penrose formalism and, simultaneously, allow the reader to understand both the physical and geometrical meanings of each step of the derivations. The technique developed is well suited for perturbation analyses. Consequently, the perturbed wave equations for massless fields are examined. The notation has …

"Address To Faculty And Students", Timothy Francis Leary

Special Collections: Oregon Public Speakers

Dr. Leary's first speech at Portland State University was ten years prior to this date. The recording of his 1967 talk was stolen from the Portland State library.

Infrared Observations Of Hii Regions And Comet West, Paul A. Heckert

Physics & Astronomy ETDs

In Chapter 1, I outline the methods of making ground-based infrared observations. I concentrate on the observational procedures rather than the instrumental design. Near-infrared observations of S 156A, _S 158A, S 159A, S 162A₁, S 228, and G 45. 5 + 0 .1 (#2) made with a beam size of ̴1 are used to estimate the total near infrared flux. After correcting for the line of sight extinction the near infrared luminosities are greater than the Lyman-α luminosities inferred from radio observations. A strong double peaked infrared source was discovered near the region of G 25.3-0.1. The infrared …

Plasma Sheath Analysis By Computer Simulation, Leo J. Rahal

Physics & Astronomy ETDs

The time development of a fully ionized, dense two-component plasma is investigated through the use of a one-dimensional particle simulation code. The plasma is initially composed of two distinct regions. One region is a uniform plasma in which electrons and ions are at the sane temperature and have no electric fields due to charge separ­ation. The other region contains a charge separation of electrons and ions resulting in an electric field. There also exists an electron current which produces a confining magnetic field. This is the sheath region between the neutral plasma and the confining magnetic field. The simulation occurs …

Theoretical Studies Of Nucleic Acid Sugar Ring Analogs, Ali-Reza Hashemi-Attar

Physics & Astronomy ETDs

Extended Hueckel theory (EHT) was used to study analogs of sugar rings in nucleic acid monomers. The energy gradient in a variable metric algorithm was used to find the potential energy along the pseudorotation path. Use of the energy gradient made it possible to permit 34 degrees of freedom in a molecule. Seven molecules and their isomers were studied. These were: 3-hydroxy2-methyl tetrahydrofuran, 2-ami no-4-hydroxytetrahydrofiJran, 5-ami no3-hydroxy-2-methyltetrahydrofuran (deoxyribonucleic acid analog), 3,4-dihydroxy-2-methyltetrahydrofuran, 2-amino-3,4-dihydroxytetrahydrofuran, 2-amino-5-methyltetrahydrofuran, and 2-amino-3,4-dihydroxy-5-methyltetrahydrofuran (ribonucleic acid analog).

It was shown that the difference in sum of total overlap populations (TOP) for all pairs of atoms between two related conformations …

El Viento De Las Estrellas, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

¿Dónde Está El Límite Del Universo?, Aldemaro Romero Jr.

Publications and Research

No abstract provided.

The Nitrogen Dayglow On Mars, Jane L. Fox, Alexander Dalgarno, E. R. Constantinides, G. A. Victor

Physics Faculty Publications

The ultraviolet dayglow spectrum arising from emission of N₂ in the Mars atmosphere is predicted. The intensities are such that a high-resolution spectrum should readily reveal the presence of N₂ at the abundances suggested by the Viking experiments.

Solar Magnetoatmospheric Waves-A Simplified Mathematical Treatment, John A. Adam

Mathematics & Statistics Faculty Publications

The inhomogeneous wave equation for a special class of magnetoatmospheric waves is formally solved, and the principle of stationary phase used to provide information on the group velocity properties of such waves. General results are presented concerning the associated mechanical energy flux. The basic problem considered is relevant to waves initiated by sudden events in the solar atmosphere.