Digital Commons Network^™

Direct Current-Excited Cw Co² Metal Waveguide Laser, Fahad S. Al-Mashaabi, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

A novel design for a dc-excited cw CO₂ metal waveguide laser has been developed in which a slotted hollow cathode also doubles as a metal waveguide for the cavity modes. This design has been implemented in a compact structure that produces over 1 W of cw 10.6-µm radiation. The discharge characteristics, laser gain, and laser output have been studied as functions of various discharge parameters. The advantages of the transverse discharge of the slotted hollow cathode geometry include low voltage, positive impedance, rugged structure, and high optical gain. Overall efficiency is comparable with that of conventional longitudinal CO² lasers. The …

Density-Dependent Convective Flow In Closed Basins, Kim L. Mccleary

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Great Basin is a region of the Basin and Range Physiographic Province, which is completely isolated hydrologically from the sea. All precipitation that falls within the Great Basin is lost from the land surface or from the surface of closed inland lakes through evapotranspiration. Playas are often found at the base of these undrained basins. This study focuses on subsurface groundwater flow patterns in closed basins. Because all discharge from the basins occurs via evapotranspiration on and near the playa, the water table of the aquifer beneath the playa is often just below the ground surface. Fluctuations of the …

Automatic Meshing Of Free-Form Deformation Solids, Ssuta S. Hsu

Theses and Dissertations

Development of computer models and subsequent finite element analysis, are important aspects of modern engineering design. In this process, the geometry creation and finite element analysis software are well developed; however, the process of discretizing a geometry into a proper finite element model is time consuming and tedious. The work presented here uses the free-form deformation method to create smooth solid models, and invokes a solid subdivision and transition method to generate the hexahedron finite elements. The combination of these two techniques provides an automatic mesh generator that is easy to use, creates acceptable hexahedron elements for finite element analysis, …

Agricultural Pesticide Hazard To Groundwater In Utah, Hubert Eisele, Majid Ehteshami, Richard C. Peralta, Howard M. Deer, Terry T. Tindall

Civil and Environmental Engineering Faculty Publications

We gratefully acknowledge the funding support of the Utah Department of Agriculture and the following offices at Utah State University. The Department of Agricultural and Irrigation Engineering, the International Irrigation Center, the Department of Animal, Dairy and Veterinary Sciences, the Department of Soil Science and Biometerology, and the University Extension Services.

Acuta Enews April 1989, Vol. 18, No. 4

ACUTA Newsletters

In This Issue

President's Message

Party Line

User Groups

1989-90 Dues Notices

Gallaudet University

University of Missouri Adds Video Instruction To Beat The Highway Blue

Wake Forest University Telecommunitcations

Administrative Director's Office

Sky-high satisfaction with SkyDome contract

Stress Interference In A Transversely Isotropic Body Under Axisymmetric Loading, Stephen M. Heinrich, J. Y. Wang

Civil and Environmental Engineering Faculty Research and Publications

An unbounded homogeneous transversely isotropic body of revolution containing two twin spheroidal cavities is subjected to an axisymmetric loading. The axis of loading symmetry coincides with the axis of elastic symmetry of the material and the axis of revolution of the body. The elasticity solution is obtained in series form utilizing the displacement potential representation for the equilibrium of transversely isotropic solids, and numerical results are presented for the cases of two spherical cavities perturbing uniaxial and hydrostatic tension fields in certain hexagonal crystals and in isotropic materials. Of primary interest is the influence of cavity spacing and material type …

Computational Aspects Of Chance-Constrained Sustained Groundwater Yield Management, R. R.A. Cantiller, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A methodology for including chance-constraints in models for maximizing regional sustained-yield groundwater extraction is presented. The procedure utilizes the spatially distributed mean and variance of saturated thickness in a confined aquifer. This data is derivable from kriging, a geostatistical technique. The technique is applied to a scenario of somewhat egalitarian agricultural development dependent on groundwater. Decision makers in this situation know that groundwater availability is insufficient to supply all potential demand. They plan to implement a sustained yield groundwater extraction strategy. They know that because of uncertain knowledge of aquifer parameters, at some point in the future, available groundwater in …

Convective Regimes In Reactive Fluid Media Due To The Interaction With Catalytic Surfaces, Hendrik J. Viljoen, Jorge E. Gatica, Vladimir Hlavacek

Papers in Reaction Kinetics

Reactive fluid media enclosed in a cavity with a catalytic surface are analyzed. Nonisothermal chemical reactions on this surface can lead to convective instabilities. A simplified model is developed by using a low-order truncation of a Fourier-type expansion and employing the Galerkin method. A linear stability analysis is presented and it is shown that, under certain conditions, the marginal curve for the onset of oscillatory instabilities can lie below that for monotonic ones. The stability of the convective modes is studied by nonlinear stability analysis and it is shown how they can evolve into periodic and nonperiodic motion patterns. Numerical …

Irish Building Services News

Building Services Engineering

No abstract provided.

A Microcomputer Based Non-Invasive Cardiopulmonary Monitor Using A Microwave Interferometer, Tanmoy K. Basu

Theses

With a microwave interferometer the vibrational velocity of the anterior (front), as well as posterior (back) chest wall can be monitored and recorded. The recorded signals are a reflection of the mechanical cardiac activity within the chest cavity, as opposed to Electrocardiogram (ECG) which is a reflection of the electrical cardiac activity. The interferometer recordings are obtained with no physical contact between the instrument and the subject. Moreover, the subject can be fully clothed since microwave energy readily passes through normal dry clothing.

A microwave interferometer that is capable of detecting the vibrational velocity of the surfaces of the chest …

Thermodynamic And Leaching Studies Of Various Systems, Satya D. Rami

Theses

The group contribution approach is a reliable and fast method for the prediction of liquid phase activity coefficients in none lectrolyte, nonpolymeric mixtures at low to moderate pressures and temperatures between 300 and 425 K. It has become widely used in practical chemical engineering applications in cases where little or no relevant experimental information is available.

The two group contribution methods examined in the course of this work, are the Knox and & UNIFAC models. Group interaction parameters are evaluated for each of these models and results compared. Although the results for both models are similar when sufficient data are …

A Wideband Continuous Phase Shifter For Ka-Band, William J. Tanis

Theses

The design, fabrication and test of a 45 degree microstrip phase shifter capable of full Ka-band performance is presented. The design uses a Lange coupler with two ports terminated with beam-lead varactor diodes to provide continuous phase shift. Although this concept has been employed at X-band and below, this thesis demonstrates its feasibility for wideband use at frequencies as high as 40 GHz. The design uses thin-film capacitors, beam-lead diodes, simulated grounds, and air bridges to achieve a planar geometry and to simplify the production process. Detailed test results using various test circuits are shown for comparison to actual phase …

Design Of A Lan Based Data Acquisition System For Sensor Applications, Krishna Murthy Uppunda

Theses

This thesis presents the design of a local area network (LAN) based data acquisition system for sensor applications. The circuit designed forms the robotic LAN (RLAN) interface between the sensor IC nodes and the ARCNET network. The RLAN network uses two packet protocols. The sensor data request (SDR) packet is received by the sensor IC nodes and the sensor transmits the sensor data (SD) packet. The RLAN interface provides a two way communication between the sensors and the ARCNET network. Whenever an ARCNET node receives the SDR packet, it stores the packet temporarily in a 1k RAM buffer. The RLAN …

The Planar Singular Solutions Of Stokes And Laplace Equations And Their Application To Transport Processes Near Porous Surfaces, Ashok S. Sangani, S. Behl

Biomedical and Chemical Engineering - All Scholarship

The planar singular solutions of Stokes and Laplace equations are derived and applied to a number of transport problems associated with porous surfaces. The velocity, pressure, concentration, and temperature slip coefficients are determined exactly for the semi-infinite periodic arrays of spheres and these are compared with the predictions of two approximate continuum theories formulated by Brinkman [Appl. Sci. Res. Sect. A I, 27 (1947)] and Chang and Acrivos [J. Appl. Phys. 59, 375 (1986)] to assess the utility of such theories in accurately predicting various overall properties related to the porous surfaces. It is found that in general these theories …

Spring 1989, 90.9 Wmpg Fm

WMPG Program Guides

Newspaper format

Summer 1989, 90.9 Wmpg Fm

WMPG Program Guides

Newspaper format

Santa Clara Magazine, Volume 31 Number 2, Winter 1989, Santa Clara University

Santa Clara Magazine

10 - MANUFACTURED MOTHERHOOD A Catholic theologian looks at reproductive technology.

16 - ELECTION '88 Will Bush put a new face on Uncle Sam?

20 - IN THE FACE OF AIDS What alumna Sharon Kugler '81 learned hel ping AIDS sufferers.

23 - ON A ROLL New York's hottest director is SCU's Ron Lagomarsino '73.

25 - DO JOBS AND COLLEGE MIX? Alumni and students tell how they fit part-time jobs into their schedules/

Physical Aspects Of Charged Particle Track Structure, R. H. Ritchie, R. N. Hamm, J. E. Turner, H. A. Wright, J. C. Ashley, G. J. Banks

United States Department of Energy: Publications

A plasmon generated by a swift charged particle constitutes a coherent excitation about the particle track. We discuss the physics of the plasmon in condensed matter and its effects on electron transport in liquid water. Criteria for the existence of the plasmon III a given substance, Its characteristics when generated by a swift charged particle, its representation in impact parameter space, and its decay into localized excitations are described. We describe how plasmon excitation and decay are implemented in our Monte Carlo code, OREC, and how track structure calculations are affected by this mode.

Subsurface Transport Of Contaminants, John E. Mccarthy, John M. Zachara

United States Department of Energy: Publications

Contaminants originating from human activities have entered the subsurface environment through waste disposal practices, spills, and land application of chemicals. The establishment of effective disposal and isolation procedures for chemical wastes, the protection of public health, and the amelioration of subsurface contamination rely on the ability to predict the velocity at which contaminants move through the vadose (unsaturated) and saturated zones. However, attempts to describe and predict contaminant transport cannot succeed if major pathways and mechanisms for transport are not defined.

Most approaches to describing and predicting the movement of contaminants treat groundwater as a two-phase system in which contaminants …

Effect Of Oxygen Concentration On The Formation Of Malondialdehyde-Like Material In A Model Of Tissue Ischemia And Reoxygenation, Steven C. Salaris, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This study was conducted to explore the functional relationship between oxygen concentration during tissue reoxygenation after ischemia and the extent of postischemic lipid peroxidation, an indicator of reoxygenation injury. Excised rat liver or kidney tissue was rendered ischemic for 1 h at 37°C, minced into 1 mm3 fragments, and then reoxygenated for 1 h in flasks of buffered salt solution containing various amounts of oxygen. Production of malondialdehyde-like material (MDA) was measured to indicate lipid peroxidation. MDA production was minimal at oxygen tensions less than 10 mmHg, increased sharply from 10 to 50 mmHg, and plateaued at approximately 100 mmHg. …

The Multiprocessor System With A Fairly Weighted Global Bus Arbitration Circuit, Shinobu Doi

Theses and Dissertations

The objective of this thesis is to investigate various multiprocessor system structures and to implement and test the resultant system configuration that offers high reliability and availability, ease of expansion, ease of programming, and increased computing performances. The resultant system is a MC68000 based tightly coupled multiprocessor system with large local memories and local I/Os, arbitrated by a specially designed arbitration circuit to implement pseudo random global bus granting. Each of the computer modules is an enhanced independent uniprocessor system with channel access switches to access the global memory. In its multiprocessor mode one computer module cooperates with the other …

Enhancing The Adoption Of Soil Conservation Practices With Targeted Educational Programs, David P. Shelton, Elbert C. Dickey, Paul J. Jasa, David A. Biere

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Two independent, but closely related, grant funded educational programs have been developed and implemented to reduce soil erosion in selected areas of eastern Nebraska, U.S.A. Traditional extension programming methods as well as other more nontraditional approaches have been extensively used. In one program, encompassing 220,000 ha of cropland, annual soil erosion has been reduced by 2.5 Mt and annual fuel savings of 1.5 ML have been achieved through a reduction in the number of tillage operations. During a one-year period in the second project, more than 81,000 m of terraces were constructed, which resulted in an annual soil erosion reduction …

Soil Phase Photodegradation Of Toxic Organics At Contaminated Disposal Sites For Soil Renovation And Groundwater Quality Protection, W. M. Moore, R. Ryan Dupont, J. E. Mclean

Reports

Accurate assessment of the potential for contaminated soil remediation requires detailed knowledge of the fate of waste constituents within the soil environment. For many non-biodegradable organics compounds, photochemical degradation may provide a potential pathway for the removal of such compounds from soil surfaces. A study was conducted to evaluate the rate of photodegradation of ten hazardous organic compounds from three soils, silica gel, and four soil minerals (kaolinite, montmorillonite, illite, and calcite) under conditions of controlled irradiation. In addition, the effect of siz amendment treatments (methylene blue, riboflavin, hydrogen peroxide, diethylamine, peat moss, and silica gel) on the rates of …

Sludge Digestion By Anaerobic Fluidized Beds. I: Lab Performance Data, Ju-Chang Huang, Bill T. Ray, Yao Jiang Huang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study was undertaken to evaluate the laboratory performance of the anaerobic fluidized bed digesting secondary biological sludge at 35° C with four hydraulic-retention times (HRTs): 1, 2.5, 5, and 10 days. In addition, the effects of both operating temperature (15° C, 25° C and 35° C) and the initial sludge solubilization on the digester performance were also examined. It was found that at 35° C, an adequate degree of sludge digestion was obtainable with an HRT of only 1-2 days if the influent biological sludge was presolubilized by treatment with 17.5 meq/L of sodium hydroxide. If no presolubilization was …

Permeability Of Clays Under Organic Permeants, Janardanan O. Uppot, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A Magnesium Montmorillonite and a Kaolinite Clay Are Subjected to Organic and Inorganic Permeants to Study the Changes in Permeability Caused by the Reaction between Clays and Permeants. the Permeants Are Acetic Acid, Aniline, Methanol, and Xylene. Tests Are Conducted in Specially Designed and Constructed Flexible Wall Permeameters that Provide Precise Measurements of Pressures and Flows. Increases in Clay Permeability Due to Clay-Permeant Chemical Reactions Are Measured to Be on the Order of Two to Three Times the Original Permeability. This is in Contrast to the 100 to 1,000 Times Increases Reported by Others. the Writers Believe that the Large …

Axisymmetric Vibrations Of Reinforced Orthotropic Shallow Spherical Caps, Victor Birman, George J. Simitses

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Axisymmetric vibrations of reinforced shallow, spherical caps manufactured from orthotropic materials are considered. The closed form solution is obtained for the natural frequency of the cap with a clamped and immovable circular edge by assuming that the motion component parallel to the cap boundary plane (in plane) is negligible. Parametric studies are performed to assess the effect of various geometric and structural parameters on the natural frequency of the cap and, most importantly, to identify the most influencing parameters of the problem. From the generated data, it is concluded that the national frequency increases with increasing extensional stiffness and eccentricity …

The Effects Of Bandwidth Limiting Tuning Elements On A Synchronously Pumped Mode-Locked Dye Laser, Bahram Zandi

Dissertations and Theses

In this study an improved description of the bandwidth limiting tuning filters has been introduced into a semiclassical model for a synchronously pumped mode-locked dye laser system. This model is an improvement over the traditional rate equation approach since it has detailed representations of the energy levels, rotational distribution, and coherence effects. The new set of equations has been solved numerically using the best available values for the various parameters, and autocorrelations have been computed for a range of different length detuning and bandwidth limiting elements. In the experiments, an acousto-optically mode-locked argon ion laser is used to synchronously pump …

Optical Recording Aspects Of Rf Magnetron Sputtered Iron-Garnet Films, J.P. Krumme, V. Doormann, P. Hansen, H. Baumgart, J. Petruzzello, M.P.A. Viegers

Electrical & Computer Engineering Faculty Publications

The intrinsic magneto-optical readout performance in reflection is calculated for bismuth and cobalt-substituted iron-garnet films on a multilayer interference mirror at 800-, 633-, 488-, and 420-nm wavelengths and is compared with that of a trilayer medium composed of an antireflection layer, a rare-earth transition-metal film, and a metallic mirror. It is found, when disregarding inhomogeneities, like irregular domain shape, ripple of the magnetic anisotropy, and surface roughness, that iron garnets are superior to rare-earth transition-metal films at blue to near-ultraviolet wavelengths if operated at thicknesses where optical interference occurs in the magnetic layer. Optical transmittance at these thicknesses is sufficiently …

Anaerobic Biodegradation Of Trichloroethylene By Activated Carbon Fluidized-Bed, Jiunn-Horng Chern

Theses

The synthetic wastewater containing trichloroethylene (TCE) was anaerobically degraded with glucose using activated carbon fluidized-bed.

The range of TCE concentration from 26 ppb to 10.8 ppm was examined. The ratio of glucose to TCE in the influent wastewater was ranged from 26 to 805, while the TCE loading ranged from 0.025 to 1.510 mg/hr-L.

The TCE removal efficiency under these treatment conditions was found to be of 99.4%. However, the reduction of chemical oxygen demand (COD) decreased when the TCE loadings was over 0.38 mg/hr-L.

Unsaturated Column Studies Of Silty Sand Using A Conservative Tracer, Canagasabapathy Nallianathan

Theses

A laboratory study was conducted to investigate the flow and mass transport of a conservative tracer in the unsaturated phase. For this purpose, a relatively "large-scale" cylindrical column(12 in. O.D. x 4 feet long) was fabricated and equipped with tensiometer and psychrometer sensors.

The soil used in the study was a New Jersey based silty sand compacted to an average dry density of 93 lb/ft³. The soil was permeated with a 0.5 M NaCl solution infiltrated at the top of the column using a perforated spiral tube assembly. The permeant was applied at a constant rate of approximately …