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A Theoretical Study Of The Semiconductor Laser Structures With Lateral Discontinuity In The Optical Cavity, Yi Cai

Theses

A theoretical study of the semiconductor laser structures with lateral discontinuity in the optical resonant cavity is presented in this thesis. Specifically, the lateral discontinuity is referred to the lateral expansion structure newly invented for increasing the power output of semiconductor lasers while keeping single mode operation.

In the first part of the thesis (Chapter 2 and Chapter 3), an explicit expression for calculating the lateral discontinuity problems is formulated by the incorporation of mode-matching method. Our approach is based on the mode expansion theory developed for lossless micro-wave and optical fiber waveguides, but the effect of gain in active …

External Cavity Laser Power Stabilizer, Jie Ding

Theses

In this thesis, we want to design a stabilizer which does not depend on laser source--with external cavity.

In the first part of the thesis ( Chapter 2 and 3 ), we discuss the wave propagation in crystals and the modulation of optical radiation. From the main two types electro-optic modulations, Phase Modulation and Transverse Modulation, we know that the transverse modulation shows an increase in the frequency limit or useful crystal length of (1-c0/ncm)^-1, and we will use this type modulation in this thesis.

The second part of the thesis is the procedure of design and experiment. …

Bio-Oxidation Of A Model Voc In Air, Jeong Seop Shim

Theses

This study was performed to find a satisfactory regime of operation for the vapor phase bio-oxidation of ethyl alcohol, a model volatile organic compound (VOC), in a specially designed bioreactor. Ethanol was selected as a model compound representing bakery oven gas pollution. A spirally wound bioreactor module was used within which was immobilized a mixed bacterial culture from aerobic sludge. The activated sludge from municipal wastewater treatment plants readily attached with no pretreatment on the surface of the spiral biosupport which is a polymeric sheet.

The parameters studied were air flow rate and inlet concentrations of ethanol. Ethanol was injected, …

Additive Pulse Mode-Locking Using A Birefringent Optical Fiber, Sandra F. Feldman, B. A. Moore, Doreen A. Weinberger, Herbert G. Winful

Physics: Faculty Publications

A powerful and increasingly common method to mode-lock a variety of lasers is additive pulse mode-locking (APM). In this technique, a nonlinear medium is placed in an external cavity which is coupled to the main laser cavity. As a result of interference at the common mirror between the pulses returning from each cavity, significant pulse shortening may be obtained. Optical fiber is often used as the nonlinear medium, and polarization effects and fiber birefringence are generally neglected. A computer model has been developed in order to simulate the effect of using a birefringent fiber. The simulations indicate that although the …

Effective Internal Fields And Magnetization Buildup For Magnetotransport In Magnetic Multilayered Structures, Horacio E. Camblong

Physics and Astronomy

Starting with the Kubo formula for electric conductivity we derive a set of equations that define the spin diffusion that is present when current is driven through inhomogeneous magnetic media. We show the spin accumulation, or nonequilibrium magnetization, attendant to charge transport through regions of inhomogeneous magnetization is governed by the same equations found in a thermodynamic approach to magnetoelectric transport.

The Importance Of Understanding Climate And The Use Of Climate Information, Stanley A. Changnon

Journal of the Minnesota Academy of Science

In this paper, the interrelated issues of understanding climate and its importance are addressed through consideration of three factors. Considered first are the general views of climate, as seen by three principal groups who deal with climatic conditions; the public, the weather-sensitive sectors, and the scientific community. The second consideration is how the atmospheric sciences community and climatologists specifically, have helped society function. Finally, activities and knowledge of climate which are changing over time, are assessed. I want to stress these are views· developed over 43 years as an atmospheric scientist. I have had the privilege of conducting a wide …

The Binational English & Spanish Telecommunications Network, Armando A. Arias Jr.

SSGS Faculty Publications and Presentations

BESTNET was established in the early 1980's, as an effort to link universities on both sides of the U.S.- Mexico border through microwave, satellite and cable television technologies. In the late 1980's BESTNET focused primarily on the development of asynchronous computer mediated learning and teaching in an internationally networked virtual environment. For the past six years (1990's) BESTNET has strengthened its binational ties and continued its "high tech" focus through the development of active or vibrant model technology which is assisting in the creation of an on-line binational university setting that is "borderless" (albeit, seamless to the user). Today, this …

Resonance Raman Investigation Of The Radical Cation Of 1,3,5-Hexatriene, Tamas Keszthelyi, Robert Wilbrandt, Robert J. Cave, Jenifer L. Johnson

All HMC Faculty Publications and Research

The resonance Raman spectrum of the 1,3,5-hexatriene radical cation generated by v-irradiation in a Freon glass is reported. The spectrum is excited at 395 nm in resonance with the second absorption band. Identical spectra are obtained from ionized (E)- and (Z)-1,3,5-hexatriene. The presence of more than one rotamer has to be assumed to account for all the observed resonance Raman bands. The bands are assigned to a mixture of the two rotamers, calculated at lowest energy, the ttt an tct rotamers, on the basis of ab initio ROHF/6-31G calculated harmonic frequencies. The spectrum indicates that …

Strategic Sealift And National Security: Effects Of A Declining Merchant Marine And Problematic Marad-Administered Reserve Forces, Michael J. Colston

Marine Affairs Theses and Major Papers

Strategic sealift, the movement of cargo in support of deployed troops in an international conflict, relies primarily on a national asset--a National Defense Reserve Force, administered by MARAD, and a commercial asset--the US Merchant Marine. The decline of the merchant marine, along with the attendant decline and unmanageable nature of MARAD-administered forces, made sealift (which was once carried out simply by purchasing space on US carriers) the limiting factor in the successful execution of Operations DESERT SHIELD/DESERT STORM. This decline is documented in a literature review. A nine case analysis of sealift performance, examining three scenarios at three times, is …

Towing Vessel Safety: Analysis Of Congressional And Coast Guard Investigative Response To Operator Involvement In Casualties Where A Presumption Of Negligence Exist, Paul J. Cormier

Marine Affairs Theses and Major Papers

Legislation proposed by members of the 103rd Congress to address towing vessel safety resulted from three focusing events. The proposed legislation was not passed. There is a continuing need to address the human element in marine casualties. Prevention through enforcement is a viable solution to some human causal factors. Numerous personnel investigations which should have been initiated following towing vessel groundings during 1992 and 1993, were not pursued; despite a presumption of negligence that exists in grounding cases. Due to the presumption, all groundings, and particularly those attributed to human factors during a casualty investigation provide sufficient reason to initiate …

Conservation And Management Of Sri Lanka's Coastal Resources Through The Experience Of Other Countries, K.W.P. Thilakaratna

Marine Affairs Theses and Major Papers

After Sri Lanka's independence in 1948, the economic importance of the coastal areas had intensified due to development of commercial and fishery harbors, transportation, communication, and recreational facilities. Opportunities in the public administration, industry, and education sectors were other main attractions. With the introduction of international tourism in 1970, economic development of coastal areas increased further. In addition to the job opportunities provided by the industrial and commercial sectors, many people were engaged in other activities depending on coastal resources, including fishing and mining activities. Prior to 1978, there was no proper authority or mechanism to address coastal issues. legislation …

Fresh Water To Arabia By Vlcc-Fact Or Folly?, Joseph P. Power

Marine Affairs Theses and Major Papers

Population growth, industrial development and the esoteric goals of national self-sufficiency in water and food propels the arid nations of Arabia in a voracious scavenge for alternative resources of fresh water as depletion and contamination of the natural aquifers have reached critical proportions. Desalination of sea water is currently the preferred alternative source of fresh water. Recent misgivings concerning the antroprogenic discharge of desalination effluent (i.e. high temperature and high saline water) into the semi-enclosed, epicontinental waters of the Arabian Gulf question the sustainability of this process. Demonstrable deleterious affects of such a process on the marine ecosystem of the …

The Persian Gulf Oil Spill: A Case Study Of Emerging International Law On Environmental Damages During Hostilities, Esther J. Mcclure

Marine Affairs Theses and Major Papers

During the 1991 Persian Gulf War, the retreating Iraqis caused the deliberate discharge of six million barrels of oil into the shallow waters of the Persian Gulf. The immediate impact on the ecosystem was dramatic, and, because of the intense media coverage of the conflict, highly visible to the American public. The spill popularized the term 'ecoterrorism' and raised serious questions about the applicability of international law to the situation. There are numerous conventions that seek to establish standards of due diligence for the prevention of accidental pollution and to impose civil liability on those who damage the environment, but …

A Case Study Of Health Risk Communication: What The Public Wants And What It Gets, Jeannette M. Trauth

RISK: Health, Safety & Environment (1990-2002)

Dr. Trauth presents a content analysis of 40 years of coverage of a major local source of air pollution by a Pittsburgh newspaper. She also summarizes the results of a survey conducted to determine the extent to which citizens of most likely affected communities, e.g., understand health risks and desire further information.

Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle

Faculty Publications, Biological Sciences

No abstract provided.

Snake: The Plain And Its People, E. B. Bentley, Bill Bonnichsen, John C. Freemuth, Bill Hackett, Glenn Oakley, F. Ross Peterson, Mark G. Plew, Todd Shallat, Steve Stuebner

Faculty & Staff Authored Books

Idaho's longest river curves west through desert landscapes, cutting deep through ancient formations, flowing through space and time. How have humans dealt with the desert? How have we been shaped by the land? SNAKE: The Plain and Its People explores the physical and ecological roots of Idaho civilization through science, social science, photography and art.

Bird Dispersal Techniques, Thurman W. Booth

Prevention and Control of Wildlife Damage Handbook

Birds, especially migratory birds, provide enjoyment and recreation for many and greatly enhance the quality of our lives. These colorful components of natural ecosystems are often studied, viewed, photographed, hunted, and otherwise enjoyed. Unfortunately, bird activities sometimes conflict with human interests. Birds may depredate agricultural crops, create health hazards, and compete for limited resources with other more favorable wildlife species. The management of bird populations or the manipulation of bird habitats to minimize such conflicts is an important aspect of wildlife management. Problems associated with large concentrations of birds can often be reduced through techniques of dispersal or relocation of …

Open Stream Collection And Diversion: An Added Dimension In Providing Water For Grazing Animals, United States Bureau Of Land Management

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

This technical note describes an effective system for collecting water from open streams and conveying it several miles via pipeline systems to watering troughs in arid locations. Perhaps one of the greatest challenges in managing lands that produce forage for grazing animals is to strike a desirable balance between forage and water. However, on native grazing lands, this is rarely the case due to terrain and uneven distribution of water. The "open stream collection and diversion system" addresses this issue with a specific engineering solution.

Ground Water Monitoring Project For Arkansas, Phase Iii, Kenneth F. Steele, Steven S. Hill, Terry W. Nichols, H. Don Scott, Paul Vendrell, H. S. Lin

Arkansas Water Resources Center Technical Reports

This report is composed of two parts. The first part is an interpretation of the pesticide and nitrate data collected in Woodruff County based on samples collected during 1994. Because there is an indication that there were hydrological differences between 1994 and 1995, and because most of the pesticide data is from 1994, this interpretive portion is restricted to 1994 data. Six wells initially sampled in 1994 that contained pesticides had continuing contamination in re-sampling in 1994 and 1995. Part II lists a seventh well in Woodruff County that contained pesticides in February and May of 1995

Highly Reactive Forms Of Zinc And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly produced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)₂. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.

Cover - Table Of Contents

Journal of the Iowa Academy of Science: JIAS

No abstract provided.

Magpies, Thomas C. Hall

Prevention and Control of Wildlife Damage Handbook

Magpies (Pica pica and P. nuttalli) have lived in close association with humans for centuries. Magpies are found in western North America. Magpies are associated with the dry, cool climatic regions of North America. Magpies are omnivorous and very opportunistic, a characteristic typical of other corvids. Magpies, like other corvids, are intelligent birds. Magpies have come into conflict with humans in North America for quite some time. Magpies are protected as migratory nongame birds under the Federal Migratory Bird Treaty Act.

Passion Runtime Library For Parallel I/O, Rajeev Thakur, Rajesh Bordawekar, Alok Choudhary, Ravi Ponnusamy

Electrical Engineering and Computer Science - All Scholarship

We are developing a compiler and runtime support system called PASSION: Parallel And Scalable Software for Input-Output. PASSION provides software support for I/O intensive out-of-core loosely synchronous problems. This paper gives an overview of the PASSION Runtime Library and describes two of the optimizations incorporated in it, namely Data Prefetching and Data Sieving. Performance improvements provided by these optimizations on the Intel Touchstone Delta are discussed, together with an out of -core Median Filtering application.

Magnetospheric Shortcomings In Ionospheric-Magnetospheric Coupling: An Ionospheric Perspective, Jan Josef Sojka

All Physics Faculty Publications

The ionosphere, on a global scale, is reasonably well understood from a climatology perspective. However, the storm dynamics of the ionosphere are not fully understood. This partly arises from the complex response function of the Thermosphere-Ionosphere(T-I) system but also from the uncertainty in the space and time dynamics of the magnetospheric inputs to the ionosphere. In the context of M-I coupling, the ionosphere responds to magnetospheric electrodynamic forcing by altering the conductivity in the ionosphere and by plasma transport. Phenomenologically,we understand how to let the ionospheric conductivity evolve in response to local precipitation and how to transport plasma in the …

Environmental Attitudes And Knowledge: An International Comparison Among Business Students, Raymond Benton Jr., G. Ray Funkhouser

School of Business: Faculty Publications and Other Works

This article investigates international differences in environmental knowledge and attitudes among business administration students. The Environmental Knowledge and Attitude Scale, developed by Maloney, Ward, and Braucht (1975) and used by Synodinos (1990), was administered to 85 upperdivision business administration students at Loyola University Chicago and 111 upperdivision business students at the National University of Singapore. No significant differences were found between the two samples on the Knowledge, Concern, or Willingness to Act subscales. The United States students' higher mean score on the Actual Behavior subscale was significant but may only reflect relative possibilities for participation in environmental activities. Overall, the …

Synthesis And Characterization Of Binuclear And Unsymmetrical Phthalocyanines, Jiang Yang

Doctoral Dissertations

"The metal free planar binuclear phthalocyanines sharing a benzene or naphthalene ring have been synthesized and characterized. The position of Q band of binuclear phthalocyanine sharing a naphthalene ring is red shifted compared to binuclear phthalocyanine sharing a benzene ring. The compounds are shown to form the liquid crystal mesophases at room temperature.

The unique unsymmetrical phthalocyanines with steric hindrance tetraphenyl or “opposite” octaphenyl substitution have been synthesized with the aid of computer modeling. The compounds are characterized by UV-visible near IR absorption and NMR spectroscopy. Mesophase is observed by optical microscopy and differential scanning calorimetry.

The aggregation behavior has …

A Spatially Distributed Energy Balance Snowmelt Model, David G. Tarboton, Tanveer G. Chowdhury, Thomas H. Jackson

Reports

This paper describes an energy balance snowmelt model developed for the prediction of rapid snowmelt rates responsible for soil erosion and water input to a distributed water balance model. The model uses a lumped representation of the snowpack with two state variables, namely, water equivalent and energy content relative to a reference state of water in the ice phase at 0 degrees Celcius. This energy content is used to determine snowpack average temperature of liquid fraction. This representation of the snowpack is used to determine snowpack average temperature of liquid fraction. This representation of the snowpack is used in a …

Measurements And Modeling Of Snow Energy Balance And Sublimation From Snow, David G. Tarboton

Reports

Snow melt runoff is an important factor in runoff generation for most Utah rivers and a large contributer to Utah's water supply and periodically flooding. The melting of snow is driven by fluxes of energy into the snow during warm periods. These consist of radiant energy from the sun and atmosphere, sensible and latent heat transfers due to turbulent energy exchanges at the snow surface and a relatively small ground flux from below. The turbulent energy exchanges are also responsible for sublimation from the snow surface, particularly in arid environments, and result in a loss of snow water equivalent available …

Utah Water Research Laboratory Publications Listing 1989-1994, David S. Bowles, Leaunda S. Hemphill

Reports

No abstract provided.

Use Of Ion Exchange Membranes For Selective Recovery Of Aspergillus Awamori Glucoamylase And Phage T4 Lysozyme, Deborah K. Stafslein, Jeff M. Hunter, Craig E. Forney

Journal of the Iowa Academy of Science: JIAS

Our research examined whether enhanced separation and purification of mutant enzymes could be obtained on ion-exchange membranes. Solutions of three mutants of Aspergillus awamori glucoamylase were passed through an anionic exchange membrane, as well as one mutant of T4 lysozyme through a cationic exchange membrane. The mutant enzymes were modified by adding "charged fusions'', polypeptides of either aspartic acid residues to increase the overall negative charge of the enzyme or arginine residues to increase the overall positive charge. The effect of the mutations on the purification of glucoamylase from a "modified" fermentation broth were examined at two different elution pHs, …