Physical Sciences and Mathematics Commons^™

Molecular-Dynamics Study Of Phase Transitions In Alkali Azides, M. M. Ossowski, John R. Hardy, Robert W. Smith

Physics Faculty Publications

An account is presented of our studies of the order-disorder phase transitions in KN₃, RbN₃, and CsN₃. These are based on parameter-free interionic potentials based on the Gordon-Kim modified electron-gas formalism extended to molecular ions. We performed static structural relaxations and supercell molecular dynamics and predicted with reasonable accuracy the temperatures for the onset of the transitions. In particular, we address the question of how the N₃^- ions reorient to yield the transitions. We found the existence of NaCl-type high-temperature phases in disordered KN₃ and RbN₃ and argue that this …

The Weyr Characteristic, Helene Shapiro

Mathematics & Statistics Faculty Works

No abstract provided.

Legislating A Sustainable Land Ethic For New Zealand, Michèle D. Dominy

Pacific Studies

This article explores competing discourses of sustainability in New Zealand’s South Island. As active resource managers, high-country pastoralists’ conception of “country” contests predominant reductive and binary models of production/ conservation and economic resource/visual resource and suggests a more complicated dynamic between scientific and cultural paradigms of sustainability than has been acknowledged. This dynamic is captured in the internationally driven top-down concept of equitable sustainable land management with a dual commitment to both cultural and ecological diversity as defined locally, formulated as part of the United Nations Rio Declaration of 1992, agenda 21, chapter 13. I examine an emergent high-country “land …

Contributors: Vol 22 No. 3-4, The Jonathan Nāpela Center For Hawaiian And Pacific Islands Studies

Pacific Studies

Contributors list of Vol. 22 (1999): Pacific Studies Full Issue 3-4

Accounting For Change: Bringing Interdependence Into Defining Sustainability, Karen L. Nero

Pacific Studies

“Sustainability,” the key word of international development bodies currently intervening in the restructuring of the Marshall Islands economy, is defined within Western economic conceptualizations. I argue that such characterizations are incomplete: they fail to capture the full nature of the ongoing Marshallese economy by focusing too narrowly on transfers related to the Compact of Free Association and by their partial understanding of Marshallese food systems and easy dichotomies between imported and local foods. The segregation of external interventions by sector further distorts their possible impact. Structural imbalances within the Marshallese and other Pacific nations’ economies have been exacerbated by the …

Artisanal Coral Reef Fisheries And Sustainable Development: The Arno Atoll Fisheries Association, Jim Hess

Pacific Studies

The concept of sustainable development is inexact, requiring additional specification in application. How the subject of analysis is bounded will have consequences for understanding what is being sustained as well as for determining whether something is sustained. Here I examine a fisheries development project in the Marshall Islands. Shifting boundaries, I create three accounts of the project. In the first account, which focuses on resources and monetary cost and benefits, the project is clearly unsustainable. In the second account, focusing on international relations, the project sustains the relations of power and dependency. In the third account, I suggest that evaluation …

Is Tonga's Mirab Economy Sustainable? A View From The Village And A View Without It, Mike Evans

Pacific Studies

The development implications of the now-classic MIRAB economic pattern for South Pacific microstates (with economies dominated by overseas remittances and foreign aid) have attracted considerable attention. Some scholars argue the MIRAB pattern is well entrenched and can be sustained with a minimum of undesirable social and economic outcomes. Others decry the acceptance of the dependency of South Pacific nations and argue for renewed effort toward the development of self-sustaining economies. I argue that the debate must directly address the underlying social relations that facilitate and shape migration and remittances. In Tonga, the movement of people from rural areas has wide-ranging …

Hopf Bifurcation In Models For Pertussis Epidemiology, Herbert W. Hethcote, Yi Li, Zhujun Jing

Mathematics and Statistics Faculty Publications

Pertussis (whooping cough) incidence in the United States has oscillated with a period of about four years since data was first collected in 1922. An infection with pertussis confers immunity for several years, but then the immunity wanes, so that reinfection is possible. A pertussis reinfection is mild after partial loss of immunity, but the reinfection can be severe after complete loss of immunity. Three pertussis transmission models with waning of immunity are examined for periodic solutions. Equilibria and their stability are determined. Hopf bifurcation of periodic solutions around the endemic equilibrium can occur for some parameter values in two …

Alkyl Nitrates During The Prophet ’98 Summer Intensive, Kristi A. Ostling

Masters Theses

As part of the PROPHET intensive held at the University of Michigan Biological Station in northern Michigan, a gas chromatography system for making fast-turnaround measurements of C1 to C5 alkyl nitrates was developed and deployed from July 19 to August 21, 1998. Every 30 minutes, samples were automatically acquired on a small Tenax trap made from silicosteel column and injected on a GC column by thermal desorption prior to ECD detection. Tests performed to measure breakthrough and on-trap destruction indicated no breakthrough for C3, C4, and C5 nitrates and excellent stability for these compounds on the trap. Chromatographic resolution of …

Bulletin 4385 - Control Of Mediterranean Fruit Fly (Medfly) In Commercial Orchards, Sonya Broughton, Francis De Lima

Bulletins 4000 -

The Mediterranean fruit fly (Medfly) is thought to originate from tropical Africa. It is a pest in many areas of the world including Western Australia. It was first detected at Claremont in 1895 and is now found as far south as Esperance and as far north as Derby. The main area of infestation extends from Carnarvon to Bunbury.

Medfly is known to infest over 200 fruit and vegetable species. In Western Australia, stone fruit, pome fruit, citrus, guavas, figs and loquats are particularly susceptible.

A Comparison Of Training Algorithms For Dhp Adaptive Critic Neuro-Control, George G. Lendaris, Thaddeus T. Shannon, Andres Rustan

Complex Systems Faculty Publications and Presentations

A variety of alternate training strategies for implementing the Dual Heuristic Programming (DHP) method of approximate dynamic programming in the neuro-control context are explored. The DHP method of controller training has been successfully demonstrated by a number of authors on a variety of control problems in recent years, but no unified view of the implementation details of the method has yet emerged. A number of options are here described for sequencing the training of the Controller and Critic networks in DHP implementations. Results are given about their relative efficiency and the quality of the resulting controllers for two benchmark control …

Off-Line Compression By Greedy Textual Substitution, Alberto Apostolico, Stefano Lonardi

Department of Computer Science Technical Reports

No abstract provided.

A Model For Active Techniques For Compressed Video Transmission, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Towards The Evaluation Of Netcentric Scientific Applications, Shanhani Markus, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

An Adaptable Network Architecture For Multimedia Traffic Management And Control, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

String Pattern Matching For A Deluge Survival Kit, Alberto Apostolico, Maxime Crochemore

Department of Computer Science Technical Reports

No abstract provided.

Experimental Evaluation Of Design Tradeoff In Specialized Virtual Machine For Multimedia Traffic In Active Networks, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

Initial State Dependence Of Low-Energy Electron Emission In Fast Ion Atom Collisions, Robert Moshammer, Pablo Daniel Fainstein, Michael Schulz, Wayne M. Schmitt, Holger Kollmus, Rido Mann, Siegbert Hagmann, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

Single and multiple ionization of neon and argon atoms by 3.6 MeV/u Au⁵³⁺ impact has been explored in kinematically complete experiments. Doubly differential cross sections for low-energy electron emission have been obtained for a defined charge state of the recoiling target ion and the receding projectile. Observed target specific structures in the electron continuum are attributable to the nodal structure of the initial bound state momentum distribution. The experimental data are in excellent accord with continuum-distorted-wave eikonal-initial-state single ionization calculations if multiple ionization is considered appropriately.

Measuring Information Quality Of Web Site: Development Of Instrument, P. Katerattanakul, Keng Siau

Research Collection School Of Computing and Information Systems

Web sites have been extensively used to provide information to consumers. While practitioners and researchers have proposed different criteria for effective Web site design based on common sense, intuition, and rules-ofthumb, effective Web site design focusing on the quality of the information it provides has rarely been studied. In this research, we propose a framework and develop an instrument to measure the information quality of individual or personal Web sites. The theoretical foundation of this research is the information quality framework. The proposed framework and instrument were tested in an individual or personal Web site context.

Production Of The Subtropical Seagrass, Halodule Wrightii Aschers., In Lower Laguna Madre, Texas, Joseph L. Kowalski

Theses and Dissertations - UTB/UTPA

The autecology of shoal grass, Halodule wrightii Aschers., was studied at 1.2 m depth from June 1995 to February 1997 in Lower Laguna Madre (LLM), Texas. Halodule wrightii in LLM received about 47% surface irradiance, but otherwise displayed lower growth rates and biomass in nutrient-poor rhizosphere and water-column environments compared to H. wrightii populations in other Texas estuaries. High tissue N content and low C:N ratios belied low growth dynamics. Halodule wrightii in LLM is probably nutrient limited. A high nutrient demand by H. wrightii in a nutrient-poor environment may explain, in part, its gradual displacement by Thalassia testudinum and …

Calibration, Installation Techniques, And Initial Measurements For Vertical Resistivity Probes Used In Hydrogeologic Investigations, Jeffrey Mark Groncki

Masters Theses

Vertical Resistivity Probes (VRPs) are being increasingly used in a variety of applications where detailed vertical resistivity information in both the vadose and saturated zones is needed. All the different possible array types and spacings must be calibrated for the effect of the 2" (outer diameter) insulating PVC cylinder on which the electrodes are mounted. Apparent resistivities must be corrected by calibration factors. Varying the installation parameters greatly influences the measured apparent resistivity because of the disturbed annulus and the composition of the backfill materials. Bentonite slurry is necessary for the installations to keep the electrodes in good contact with …

Stratigraphic Analysis Of Diamicton Units In North-Central St. Joseph County, Michigan, Andrew C. Flint

Masters Theses

Seven subsurface glacial diamicton units, including a paleosol, have been characterized from two borings in north-central St. Joseph County, Michigan. These units have been characterized in terms of their clay mineralogy, texture, color, and stratigraphic position. t-Tests confirm that each unit displays a significant difference in mean 7A/10A peak height ratio from all other units.

Unit 4, informally called the Gray Marker tilt has been correlated between borings in this study and to the findings of others (Gardner, 1997, Nicks, in preparation). The Newbury till described by the Indiana Geological Survey (unpublished data) may also correlate to Unit 4, raising …

Detailed Dynamics Of Electron Beams Self-Trapped And Accelerated In A Self-Modulated Laser Wakefield, Shouyuan Chen, M. Krishnan, Anatoly Maksimchuk, R. Wagner, Donald P. Umstadter

Donald Umstadter Publications

The electron beam generated in a self-modulated laser-wakefield accelerator is characterized in detail. A transverse normalized emittance of 0.06 π mm mrad, the lowest ever for an electron injector, was measured for 2 MeV electrons. The electron beam was observed to have a multicomponent beam profile and energy distribution. The latter also undergoes discrete transitions as the laser power or plasma density is varied. In addition, dark spots that form regular modes were observed in the electron beam profile. These features are explained by analysis and test particle simulations of electron dynamics during acceleration in a three-dimensional plasma wakefield.

Year In Review - 1999, Annis Water Resources Institute

AWRI Reviews

No abstract provided.

Tga/Ftir: An Extremely Useful Technique For Studying Polymer Degradation, Charles A. Wilkie

Chemistry Faculty Research and Publications

Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FTIR, has been used to probe the degradation of several polymeric systems. These include poly(methyl methacrylate) in the presence of various additives, graft copolymers of acrylonitrile-butadiene-styrene and styrene-butadiene with sodium methacrylate and styrene with acrylonitrile, blends of styrene-butadiene block copolymers with poly(vinylphosphonic acid) and poly(vinylsulfonic acid), and cross-linked polystyrenes. Additives may interact with poly(methyl methacrylate) by coordination to the carbonyl oxygen to a Lewis acid and the subsequent transfer of an electron from the polymer chain to the metal atom or by the formation of a radical which can trap the degrading …

Work In Progress: Automating Proportion/Period Scheduling, David Steere, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

The recent effort to define middleware capable of supporting real-time applications creates the opportunity to raise the level of abstraction presented to the programmer. We propose that proportion/period is a better abstraction for specifying resource needs and allocation than priorities. We are currently investigating techniques to address some issues that are restricting use of proportion/period scheduling to research real-time prototypes. In particular, we are investigating techniques to automate the task of selecting proportion and period, and that allow proportion/period to incorporate job importance under overload conditions.

Trace-Level Determination Of Fluorescently Labeled Phenoxy Acid Herbicides And The Study Of Their Crop Uptake And Soil Accumulation, Noura Saeed Al Nuaimi

Theses

A challenging problem facing the determination of phenoxy acid herbicides in samples is their low UV absorptivity and the interference associated with the matrix in which these analytes exist. This thesis is concerned with improving the detection limits of this group of herbicid as well as reduce or eliminate interference associated with the sample matrix.

Native phenoxy acid herbicides could be analyzed by high performance liquid chromatography (HPLC) with ultraviolet detection. Phenoxy herbicides were analyzed by HPLC employing a gradient conditions that allowed baseline resolution of all analytes used in this study in approximately 20 min. However, the average detection …

Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole

UNLV Theses, Dissertations, Professional Papers, and Capstones

A 100 meter X 100 meter study site was chosen at White Rock Springs in Red Rock Canyon National Conservation Area, Nevada. To examine Syntrichia caninervis, a desert crustal moss, reciprocal transplantations (20 mm and 40 mm diameter cores) were performed between shaded to shaded, exposed to exposed, and shaded to exposed microsites to determine if it was possible to transplant the study organism with reasonable survivorship. Transplants were inspected following rain events for percent hydration, number of dead stems, and change in percent cover. Data indicated that there was a low mortality rate of S. caninervis stems, and few …

Wiyn Open Cluster Study. Ii. Ubvri Ccd Photometry Of The Open Cluster Ngc 188, Ata Sarajedini, Ted Von Hippel, Vera Kozhurina-Platais, Pierre Demarque

Publications

We present high-precision UBVRI CCD photometry of the old open cluster NGC 188. Our color-magnitude diagram extends from near the red giant branch tip to as faint as ~5 mag below the main-sequence turnoff. From an analysis of these data along with published photometry for M67, we draw the following conclusions: (1) From the UBV two-color diagram, we find a reddening of E(B ̶ V) = 0.04 ± 0.02 for M67 and E(B ̶ V) = 0.09 ± 0.02 for NGC 188. (2) Based on main-sequence fitting to solar abundance isochrones, the distance moduli …

Characterisation Of The Effects Of Time And Pressure On A Group Of Electronic Voltage Standards, James Kevin Armstrong

Masters

Although primary metrology laboratories use standards based on the Josephson effect to maintain a local reference standard for dc voltage, artefact standards are still the standard of choice in many secondary laboratories. The National Metrology Laboratory, Dublin maintains a local reference standard for dc voltage by means of an ensemble of Zener-diode based electronic voltage standard units. Electronic voltage standards have a number of shortcomings over Josephson standards for use as a local reference standard. In particular their output voltages are influenced by several external factors. In order to make optimum use of the NML reference standard it is important …