Physical Sciences and Mathematics Commons^™

Laser Light In, 50-Mev Protons Out, Phillip F. Schewe, Ben Stein, Donald P. Umstadter

Donald Umstadter Publications

At next week's meeting of the American Physical Society Division of Plasma Physics in Seattle, three groups will independently announce their ability to generate powerful, intense streams of ions by shining ultrashort laser pulses on tiny spots of solid material. Potentially, this approach offers an alternative to bulky, expensive ion accelerators for producing high-velocity ions useful for cancer therapy and electronics manufacturing. Using a single pulse of light from Livermore's Petawatt laser, the most powerful in the world, researchers at that laboratory (Scott Wilks, 925-422-2974, [email protected]) have reported generating 30 trillion protons with energies up to 50 MeV, from a …

Rkky Interactions Between Nanomagnets Of Arbitrary Shape, Ralph Skomski

Ralph Skomski Publications

The RKKY interaction between well-separated magnetic particles in a nonmagnetic metallic matrix is calculated. It turns out that the net interaction can be mapped onto an RKKY interaction between two point-like effective moments. The effective moments exhibit a strongly oscillating dependence on the particle's size, shape, and orientation, but their magnitudes are governed by scaling laws. As a rule, magnetostatic interactions tend to suppress the RKKY effect in particles larger than about 1 nm. Surface roughness leaves the effective-moment picture unaltered but tends to yield a moderate reduction of the effective moments. The results are discussed in the context of …

Structural And Magnetic Properties Of Fept:Sio2 Granular Thin Films, C.P. Luo, David J. Sellmyer

David Sellmyer Publications

Nanocomposite FePt:SiO₂ films have been fabricated by annealing the as-deposited FePt/SiO₂ multilayers at temperatures from 450 to 650 °C. These films consist of high-anisotropy tetragonal L1₀ FePt particles embedded in a SiO₂ matrix. The structural and magnetic properties of these films were investigated. We have found that coercivity and grain size are highly dependent on the annealing temperature and SiO₂ concentration. Films with coercivities in the range from 2 to 8 kOe and grain sizes of 10 nm or less were obtained. These films have considerable potential as high-density magnetic recording media.

Mental Models For Introductory Csc Concepts, Jennifer J. Wheeler, Erika Rogers

Computer Science and Software Engineering

If is hypothesized that the development of mental models for a concept can lead to improved learning. The purpose of this paper is to identify, quantify, and analyze the mental models of students beginning to program in the UNIX environment. By focusing on 4 basic concept, this study abstracts current mental models from students and hypothesizes ways of improving these models. Ultimately, the results of the study will be incorporated into the design and implementation of a multimedia tutor. This tutor will attempt to teach people how to develop mental models in order to improve their learning.

Environmental Assessment, Decision Record, And Finding Of No Significant Impact For The Ixc Communications, Inc.'S Proposed Fiber Optic Telecommunications System, Denver, Colorado, To Salt Lake City, Utah, U.S. Department Of The Interior, Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

IXC proposes to install and operate a telecommunications system from Denver, Colorado, to Salt Lake City, Utah, to provide service to these and other western cities. The approximately 611-mile long cable would cross 116 miles of federal land administered by the BLM (all within Wyoming), 1 mile of National Forest lands administered by the Forest Service (all within Utah), and 494 miles of state, county, municipal, and private lands. Three 1.9-inch and three 2.4-inch high-density polyethylene conduits would be installed simultaneously and a fiber optic cable would be installed in one conduit; the other conduits would be used for future …

Stereoselective Determination Oftrihexyphenidyl In Human Serum By Lc–Esi–Ms, Vladimı́R Čápka, Yan Xu, Yong Hong Chen

Chemistry Faculty Publications

The antiparkinsonian drug trihexyphenidyl (THP) is currently manufactured and administered as a racemate. However, stereochemistry can play significant role in the drug’s pharmacokinetics, biotransformation, metabolism, interaction with cellular and tissue components and overall effect on human body. It is necessary to consider such a drug as a mixture of two compounds (drug enantiomers), with their own effect on the human body. The present paper describes a simple and sensitive LC–MS method for the stereoselective determination of THP in human serum. In this study, the sample was prepared by a solid-phase extraction (SPE) procedure. The enantiomer separation was done using native …

Coherence Properties Of An Atom Laser, Marek Trippenbach, Y. B. Bland, Mark Edwards, Marya Doery, P. S. Julienne, E. W. Hagley, L. Deng, M. Kozuma, K. Helmerson, S. L. Rolston, W. D. Phillips

Physics & Astronomy: Faculty Publications

We study the coherence properties of an atom laser, which operates by extracting atoms from a gaseous Bose-Einstein condensate via a two-photon Raman process, by analysing a recent experiment (Hagley et al1999 Phys. Rev. Lett.833112). We obtain good agreement with the experimental data by solving the time-dependent Gross-Pitaevskii equation in three dimensions both numerically and with a Thomas-Fermi model. The coherence is strongly affected by the space-dependent phase developed by the condensate when the trapping potential is turned off.

First Example Of A Double Stranded Helicate With Square-Planar Coordination For The Metal, Marc Zimmer, Derek A. Tocher, Goutam K. Patra, Jnan P. Naskar, Dipankar Datta

Chemistry Faculty Publications

Reaction of dichlorobis(benzildihydrazone)Ni(II) with biacetylmonoxime in 1:4 molar proportion generates diamagnetic Ni₂L₂ where LH₂ (H = dissociable oximato proton) is HO-N=C(CH₃)-C(CH₃)=N-N=C(C₆H₅)-C(C₆H₅)=N-N=C(CH₃)-C(CH₃)=N-OH. Our molecular mechanics calculations show that Ni₂L₂ is an unprecedented double stranded homotopic helicate with the metal ion having a square-planar N₄ coordination.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 9, November 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A fourteen page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

The Type Ia Supernova 1998bu In M96 And The Hubble Constant, Saurabh Jha, Peter M. Garnavich, Robert P. Kirshner, Peter Challis, Alicia M. Soderberg, Lucas M. Macri, John P. Huchra, Pauline Barmby, Elizabeth J. Barton, Perry Berlind, Warren R. Brown, Nelson Caldwell, Michael L. Calkins, Sheila J. Kannappan, Daniel M. Koranyi, Michael A. Pahre, Kenneth J. Rines, Krzysztof Z. Stanek, Robert P. Stefanik, Andrew H. Szentgyorgyi, Petri Vaisanen, Zhong Wang, Joseph M. Zajac, Adam G. Riess, Alexei V. Filippenko, Weidong Li, Maryam Modjaz, Richard R. Treffers, Carl W. Hergenrother, Eva K. Grebel, Patrick Seitzer, George H. Jacoby, Priscilla J. Benson, Akbar H. Rizvi '99, Laurence A. Marschall, Jeffrey D. Goldader, Matthew Beasley, William D. Vacca, Bruno Leibundgut, Jason Spyromilio, Brian P. Schmidt, Peter R. Wood

Physics and Astronomy Faculty Publications

We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29 spectra of SN 1998bu between UT 1998 May 11 and July 15. The well-sampled light curve indicates the supernova reached maximum light in B on UT 1998 May 19.3 (JD 2450952.8^0.8) with B\12.22^0.03 and V \11.88^0.02. Application of a revised version of the Multicolor Light Curve Shape (MLCS) method yields an extinction toward the supernova of AV\0.94^0.15 mag, and indicates the supernova was of average luminosity compared …

Intercomparison Of Retrospective Radon Detectors, R. William Field, Daniel J. Steck, Mary Ann Parkhurst, Judy A. Mahaffey, Michael C.R. Alavanja

Physics Faculty Publications

We performed both a laboratory and a field intercomparison of two novel glass-based retrospective radon detectors previously used in major radon case-control studies performed in Missouri and Iowa. The new detectors estimate retrospective residential radon exposure from the accumulation of a long-lived radon decay product, ²¹⁰Pb, in glass. The detectors use track registration material in direct contact with glass surfaces to measure the α-emission of a ²¹⁰Pb-decay product, ²¹⁰Po. The detector's track density generation rate (tracks per square centimeter per hour) is proportional to the surface α-activity. In the absence of other strong sources of α-emission in …

Teaching Object Technology In Industry Short Courses, David S. Janzen

Computer Science and Software Engineering

No abstract provided.

1991-1992 & 1996 Utah Usage Of Ems Services By Children: Year Iii Research Report, Intermountain Injury Control Research Center, U.S. Department Of Commerce

All U.S. Government Documents (Utah Regional Depository)

This study examined how Utah children used emergency medical services (EMS) and related hospital care in 1991-1992. The EMS and hospital records were linked using special software (probabilistic linkage) . The principal findings of the study concerned the care of young children less than 5 years of age. They received fewer procedures prior to being transported to a hospital and required more time at the scene for assessment. Some interventions such as splinting of fractured arms prior to transport to a hospital were related to reduced hospital charges. Ambulance and hospital charges for children were estimated to by $35,000,000 not …

The Coral Reef Fishes Of Broward County Florida, Species And Abundance: A Work In Progress, B. D. Ettinger, David S. Gilliam, L. K. B. Jordan, Robin L. Sherman, Richard E. Spieler

Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures

The inshore environment of Broward County, FL consists of three coral reef/hard bottom reef tracts, separated by sand substrate, running parallel to the coast in sequentially deeper water. At quarter nautical mile intervals, for a five mile coastline section, fishes were censused at western, eastern and crest sites of each of the three reef tracts. On SCUBA and using the Bohnsack/Bannerot point-count method, we recorded: fish abundance, species richness, size, and general habitat of an imaginary cylinder 15 m in diameter. The position of each site was recorded by DGPS after census. One hundred and eighty-one sites were censused during …

Recounting Fibonacci And Lucas Identities, Arthur T. Benjamin, Jennifer J. Quinn

All HMC Faculty Publications and Research

No abstract provided in this article.

Center For Sustainable Agricultural Systems Newsletter, November/December 1999

Center for Sustainable Agricultural Systems: Newsletter (1993–2000)

Contents:

Conference Shows Large Interest in Small Farms

University Role in Biotechnology: What Do People Say and Why?

Loss of Biodiversity a Growing Concern

A Near-Surface Microstructure Sensor System Used During Toga Coare. Part Ii: Turbulence Measurements, Alexander Soloviev, Roger Lukas, Peter Hacker, H. Schoeberlein, M. Baker, A. Arjannikov

Marine & Environmental Sciences Faculty Articles

New techniques developed for near-surface turbulence measurements during the Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean–Atmosphere Response Experiment (COARE) employ a difference in spatial scales of turbulence and surface waves. According to this approach, high relative speed of the measurements provides separation of the turbulence and surface wave signals. During the TOGA COARE field studies, highresolution probes of pressure, temperature, conductivity, fluctuation velocity, and acceleration were mounted on the bow of the vessel at a 1.7-m depth in an undisturbed region ahead of the moving vessel. The localization in narrow frequency bands of the vibrations of the bow sensors allows …

Cationic 5,10,15,20-Tetrakis(N-Methylpyridinium-4-Yl)Porphyrin Fully Intercalates At 5‘-Cg-3‘ Steps Of Duplex Dna In Solution, Anton B. Guliaev, Neocles B. Leontis

Chemistry Faculty Publications

The interaction of 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)p (T4MPyP⁴⁺ with the oligonucleotide DNA duplex [d(GCACGTGC)](2) was studied by two-dimensional ¹H NMR spectroscopy, optical absorbance, circular dichroism, and molecular dynamics simulation employing particle mesh Ewald methods. T4MPyP⁴⁺ is one of the largest aromatic molecules for which intercalative binding to DNA has been proposed, although this has been called into question by recent X-ray crystallographic work [Lipscomb et al. (1996) Biochemistry 35, 2818-2823]. T4MPyP⁴⁺ binding to [d(GCACGTGC)]₂ produced a single set of (mostly) upfield-shifted DNA resonances in slow exchange with the resonances of the free DNA. Intra- and intermolecular NOEs …

Electro-Optic Response Of Surface-Induced Nematic Order Above The Nematic-Isotropic Phase Transition Temperature, Jong-Hyun Kim, Rolfe G. Petschek, Charles Rosenblatt

Faculty Scholarship

The optical retardation of a liquid crystal above the nematic-isotropic phase transition temperature TNI and subjected to planar alignment conditions at the substrate was investigated in the presence of an electric field applied normal to the substrates. The response was found to exhibit "S"-shaped behavior with electric field, and was larger near TNI than well above TNI. The results were examined in the context of a model that permits both biaxiality and a field-induced tilt of the molecular director. The results suggest that the primary effect of the electric field is to induce biaxiality, and in consequence suppress the order …

Confined Water In Hydrophobic Nanopores: Dynamics Of Freezing Into Bilayer Ice, Jan Slovak, Kenichiro Koga, Hideki Tanaka, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Molecular dynamics simulations for a thin film of water confined to a slit nanopore are performed in order to investigate the dynamic process of crystallization of the system. The system upon freezing creates a bilayer ice crystal composed of two layers of hexagonal rings. We perform one simulation at T=257 K during which the system remains a supercooled liquid state, and another one at T=253 K during which the system freezes. Many patterns of molecular arrangement are found upon freezing, and an account is given of the origin of multiple peaks in the distributions of binding energy and …

Imaging Point Defects In A Liquid Environment: A Model Afm Study, Kenichiro Koga, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Effects of the liquid on atomic force microscopy (AFM) imaging are examined for a model system consisting of a hexagonal flake of seven Lennard-Jones (LJ) atoms as a multiatom tip, a monolayer of LJ crystal containing a single point defect as a substrate, and three-site model water as the liquid. A previous simulation [Koutsos et al., Europhys. Lett. 26, 103 (1994)] has shown that the true atomic resolution of a point defect cannot be achieved in vacuum by use of the multiatom tip. Here we examine the feasibility of such atomic resolution when both the tip and substrate are immersed …

Geosciences Newsletter- 1999, Department Of Geosciences

Geological and Environmental Sciences News

Vol.1, No. 24

• Dear Alumni and Friends
• Faculty News
• Graduate Student News
• Student News
• Alumni News
• Donations

The Prairie Naturalist Volume 31 No.4 December 1999

The Prairie Naturalist

THE FISHES OF THE UPPER MOREAU RIVER ▪ T. M. Loomis, C. R. Berry, Jr., and J. Erickson

DO INTERNAL FIRE LANES AFFECT NEST DEPREDATION RATES IN PRAIRIES? ▪ K. A. Warren and M. R. Ryan

SPECIES COMPOSITION AND TROPHIC STRUCTURE OF INSECT COMMUNITIES IN TEXAS PRAIRIES. ▪ G. N. Cameron and E. H. Bryant

FIDELITY OF MALLARDS TO ARTIFICIAL NESTING STRl!CTURES ▪ T. Yerkes

OBSERVATIONS ON REPRODUCTION IN THREE SPECIES OF BATS ▪ D. W. Sparks, J. R. Choate, and R. J. Winn

EARLIEST SEASONAL RECORD OF REPRODUCTION IN THE HOARY BAT ON THE NORTHERN GREAT PLAINS ▪ T. …

The Probe, Issue 206 – November 1999

The Probe: Newsletter of the National Animal Damage Control Association

Wildlife Damage Conferences: When, Where, and Why? -- Robert M. Timm, Editor, THE PROBE
Booklet Review:"The Problem with Skunks!!" by Edward Kellems (34 pages, illustrated. $14.95)
New NWCO Web Page url is http://www.wildlifedamagecontrol.com/nwcoa.htm

Abstracts from the 2nd International Wildlife Management Congress, Hungary
Human Disturbance as a Design Factor to Aid Displacement of Canada Geese from Urban Parks -- P. C. Whitford, Biology Department, Capital University, Columbus, OH
Leopard Problems in Nepal -- T. M. Maskey, National Parks and Wildlife Conservation Department, Kathmandu, Nepal
Elk-human Conflict Management in Banff National Park, Alberta, Canada -- J. A. McKenzie, Banff National Park Wildlife …

Light Backscatter Of Milk Products For Transition Sensing Using Optical Fibers, Frederick A. Payne, Czarena L. Crofcheck, Sue E. Nokes, Klat C. Kang

Biosystems and Agricultural Engineering Faculty Publications

Transition sensors are needed, particularly in the dairy industry, for detecting transitions in pipe flow systems from product-to-water or product-to-product (such as from chocolate to vanilla ice cream mix). Transition information is used to automatically sequence valves to minimize product waste. Optical fibers were used to measure light backscatter between 400 and 950 nm as a function of milk concentration in water and milkfat concentration in milk. The normalized response (100% for product and 0% for water) as a function of product concentration in water was approximately logarithmic for skim milk between 400 and 900 nm and approximately linear for …

Student Fact Book, Fall 1999, Twenty Third Annual Edition November 1999, Wright State University, Office Of Student Information Systems, Wright State University

Wright State University Student Fact Books

The student fact book has general demographic information on all students enrolled at Wright State University for Fall Quarter, 1999.

Velocity Distributions Of C Atoms In Co+ Dissociative Recombination: Implications For Photochemical Escape Of C From Mars, Jane L. Fox, Aleksander Hać

Physics Faculty Publications

We have carried out Monte Carlo calculations to determine the velocity distributions of C atoms produced by dissociative recombination of CO⁺ using recent data for the branching ratios of various allowed channels and ion and electron temperatures appropriate to the Martian thermosphere. We find that the fractions of ¹²C atoms with velocities greater than the escape velocity are ∼ 0.66 and ∼ 0.62, and those for ¹³C are ∼ 0.47 and ∼ 0.48 at the plasma temperatures characteristic of the exobases at low and high solar activities, respectively. The ratio of the escape fractions of ¹³C …

A New Numerical Model Of Coupled Inland Ice Sheet, Ice Stream, And Ice Shelf Flow And Its Application To The West Antarctic Ice Sheet, Christina L. Hulbe, D. R. Macayeal

Geology Faculty Publications and Presentations

We have developed a dynamic/thermodynamic finite element numerical model that couples inland ice sheet, ice stream, and ice shelf dynamics. This new model stands apart from other whole ice sheet models in its explicit treatment of ice stream flow. Additionally, the model accounts for both horizontal and vertical advection and diffusion of temperature in the flowing ice. In present day simulations of the West Antarctic Ice Sheet (WAIS), modeled ice velocity agrees well with observed ice flow. In particular, the model reproduces the pattern of speed variation across ice streams although the continuous downstream speed up of ice flow cannot …

Strain Splitting Of The Gamma(5) And Gamma(6) Free Excitons In Zno, D. C. Reynolds, David C. Look, B. Jogai, C. W. Litton, T. C. Collins, M T. Harris, M. J. Callahan, J. S. Bailey

Physics Faculty Publications

High-quality ZnO crystals have been grown by vapor-phase techniques and by the hydrothermal method. Depending on the surface preparation technique, some hydrothermally grown crystals contain strain. These strains result in energy shifts of the free excitons as well as relaxation of the selection rules. The Γ₆ unallowed exciton is observed in these samples without the application of a magnetic field. The Γ₆ exciton is also observed to split in a strain field, consistent with the Γ₉ symmetry for the top valence band in ZnO. The Γ₅ and Γ₆ excitons have been observed to split in …

An Access-Control Calculus For Spanning Administrative Domains, Jon Howell, David Kotz

Computer Science Technical Reports

In our quest to give users uniform access to resources unimpeded by administrative boundaries, we discovered that we needed transitive sharing among users, with the possibility of restricted access along each sharing link. To achieve that goal, we extend Lampson et al.'s calculus for access control to support restricted delegations. We discuss the advantages of our extension, including the simplification of constructs like ACLs and statement expiration. We also apply our extension to model the Simple Public Key Infrastructure and make suggestions about its future development. Our extended calculus exposes some surprising consequences in such systems that use restricted delegation.