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Building Services Engineering

No abstract provided.

A New Method For The Determination Of Flow Directions And Contributing Areas In Grid Digital Elevation Models, David G. Tarboton

Civil and Environmental Engineering Faculty Publications

A new procedure for the representation of flow directions and calculation of upslope areas using rectangular grid digital elevation models is presented. The procedure is based on representing flow direction as a single angle taken as the steepest downward slope on the eight triangular facets centered at each grid point. Upslope area is then calculated by proportioning flow between two downslope pixels according to how close this flow direction is to the direct angle to the downslope pixel. This procedure offers improvements over prior procedures that have restricted flow to eight possible directions (introducing grid bia) or proportioned flow according …

Feasibility Considerations Of An Optimal Pumping Strategy To Capture Tce/Pce Plume At March Afb, Ca, Mohamed A. Hegazy, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

TCE/PCE contaminated groundwater from March AFB has reached off-base supply wells. Further migration of the contaminants can endanger other downstream water supply wells.

Historical Water Use Backcasting Study Luke Air Force Base, Arizona, Mohamed A. Hegazy, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

The goal of this report is to present historic (backcast) water use for Luke Air Force Base (LAFB), Arizona for 1941 through 1961. Historic water use (including system losses) from LAFB records can be used as groundwater pumping amounts because groundwater extracted from the underlying aquifer was the sole water source. Historical water use amounts were derived primarily using regression analysis and the Installation Water Resources Analysis and Planning System - Air Force (IWRAPS-AF). IWRAPS-AF is a computer software package designed to forecast or backcast water use and assess the effectiveness of conservation measures at Air Force Installations (Willett et. …

The Fate And Disposition Of Metolachlor And 2, 4-D Under Irrigated Corn And Turf, Ghassan R. Musharrafieh, Richard C. Peralta, Robert W. Hill, Howard M. Deer

Civil and Environmental Engineering Faculty Publications

A field lysimeter experiment was conducted during the summers of 1993 and 1994, at the River Laboratory, Utah State University, Logan, Utah. The intent was to study the fate and disposition of metolachlor and 2,4-D in a one dimensional soil system. Metolachlor was applied to corn and 2,4-D was applied to turf. The mobility, persistence, and degradation of these herbicides were investigated in the field lysimeters using four irrigation treatment levels on corn and two irrigation levels on turf. The four irrigation levels applied to corn were 0, 30, 60, and 120 percent of potential evapotranspiration. The two irrigation levels …

Across-Column Cracks And Axial Splits In S2 Saline Ice Under Compression, E. M. Schulson, S. Qi, J. S. Melton, E. T. Gratz

Dartmouth Scholarship

Experiments on plate-like specimens have established that across-column cracks from within S2 (columnar) salt-water ice when compressed uniaxially along a direction inclined to the long axis of the grains. Wing cracks initiate from the across-column cracks and lengthen into axial splits when the ice is rapidly deformed; correspondingly; the macroscopic behavior changes from ductile to brittle. The across-column cracking is attributed to grain-boundary sliding, and the splitting to the suppression of crack-tip creep.

Dynamic Site Periods For The Jackson Purchase Region Of Western Kentucky, Ron Street, Zhenming Wang, Edward W. Woolery, Issam E. Harik, David L. Allen, Kevin G. Sutterer

Kentucky Transportation Center Research Report

Bridges, overpasses, and other engineered structures in the Jackson Purchase region of Western Kentucky are, of necessity, built on a thick column of loose to semi-consolidated sediments. Because these sediments tend to amplify seismically induced ground motions at preferred periods, structures with natural periods close to the preferred periods of amplification of the ground motions are particularly vulnerable to damages during an earthquake because of in-phase resonance.

For this report, conventional seismic refraction and reflection techniques were used to determine the shearwave velocities of the more poorly consolidated, near-surface sediments for a matrix of sites in the region. Conventional seismic …

Traffic Flow And Safety Evaluation Of Fayette County Schools Part Ii, Samantha S. Jones, Jerry G. Pigman, Kenneth R. Agent

Kentucky Transportation Center Research Report

In cooperation with Fayette County Schools, an evaluation of traffic flow and safety was conducted at school sites in Fayette County. The purpose of this evaluation was to identify potential safety risks currently existing at selected schools, recommend actions to reduce risks, and to decrease traffic congestion in and around school properties.

This report is a continuation of the traffic and safety project submitted to Fayette County Schools in September 1996. For this project, three schools were identified by Fayette County Schools as having traffic flow or safety problems that could benefit from detailed evaluation. The three schools were Clays …

Ccfss News February 1997, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Minimizing Channel Density With Movable Terminals, Ronald I. Greenberg, Jau-Der Shih

Computer Science: Faculty Publications and Other Works

We give algorithms to minimize density for VLSI channel routing problems with terminals that are movable subject to certain constraints. The main cases considered are channels with linear order constraints, channels with linear order constraints and separation constraints, channels with movable modules containing fixed terminals, and channels with movable modules and terminals. In each case, we improve previous results for running time and space by a factor of L/\lgn and L, respectively, where L is the channel length, and n is the number of terminals.

Analytical Solutions Of Openings Formed By Intersection Of A Cylindrical Shell And An Oblique Nozzle Under Internal Pressure, Hengming Cai

Dissertations

Since several decades ago, many authors have published their research results about local stress distributions of shells and shell-nozzles both analytically and numerically. However, there has not been a published paper, which deals with analytical solutions of cylindrical shell and oblique nozzle, even though in the case of openings formed by intersection of a cylindrical shell and an oblique nozzle.

A comprehensive analytical study of local stress factors at the area of openings formed by intersection of a cylindrical shell and an oblique nozzle under internal pressure is presented in this dissertation.

By means of traditional approach in theory of …

Adaptive Distributed Detection With Applications To Cellular Cdma, Jian-Guo Chen

Dissertations

Chair and Varshney have derived an optimal rule for fusing decisions based on the Bayesian criterion. To implement the rule, probabilities of detection P_D and false alarm P_F for each detector must be known, which is not readily available in practice. This dissertation presents an adaptive fusion model which estimates the P_D and P_F adaptively by a simple counting process. Since reference signals are not given, the decision of a local detector is arbitrated by the fused decision of all the other local detectors. Adaptive algorithms for both equal probable and unequal probable sources, for independent …

Synthesis And Characterization Of Lpcvd Sic Films Using Novel Precursors, Mahalingam Bhaskaran

Dissertations

A unique low pressure chemical vapor deposition (LPCVD) process has been developed to synthesize amorphous and crystalline SiC films using environmentally benign chemicals. The interrelationships governing the process variables, compositions and select properties of the resulting films were established. Such films can be used to produce high quality mask membrane for x-ray lithography. These films can also be used in fabricating high power electrical devices, and hetrojunction devices in conjunction with silicon.

Amorphous SiC films were synthesized using a single precursor, ditertiarybutylsilane, at temperatures below 850°C. Compositional analysis performed on these deposits revealed that, in the deposition temperature range of …

Bilinear Time-Frequency Representations Of Heart Rate Variability And Respiration During Stress, Rindala Saliba

Dissertations

Recently, joint time-frequency signal representation has received considerable attention as a powerful tool for analyzing a variety of signals and systems. In particular, if the frequency content is time varying as in signals of biological origin which often do not comply with the stationarity assumptions, then this approach is quite attractive. In this dissertation, we explore the possibility of better representation of two particular biological signals, namely heart rate variability (HRV) and respiration. We propose the use of time-frequency analysis as a new and innovative approach to examine the physical and mental exertion attributed to exercise. Two studies are used …

Two Dimensional Agonistic Control, Daqing Yang

Dissertations

The conventional method of precise multiple-axis motion control entails use of a multiple axis positioning system with each axis carrying not only the workpiece but also the positioning system of the remaining axes. The resultant structure is heavy, sluggish, and expensive. An alternative positioning technique is being investigated in which the motion of the workpiece is controlled by pulling it with tendons, each of which has its own actuator. Since the actuators can be mounted on the base of the structure instead of being carried by motion system of the other axes, they can be relatively large and powerful without …

Evaluation Of Environmental Characteristics Of Wtp Residuals For Disposal In Monofills, Ping Tian

Dissertations

Disposal of water treatment plant (WTP) have raised great concerns due to the stringent water quality standards and environmental regulations, and limited availability of land for ultimate disposal. The ultimate disposal of water treatment plant residuals by using monofill may be one of the most economical, and feasible options. Design and operation of such a monofill will be simple because of the uniformity of the characteristics of WTP residuals.

The objectives of this project were to determine the environmental characteristics of WTP residuals and to apply these characteristics for the design of monofills and development of the metal leaching model …

Counterpulsation Cardiac Assist Device Controller Defection Filter Simulation And Canine Experiments, Carl Edward Werner

Dissertations

Electronic control systems for counterpulsation Cardiac Assist Devices (CADs) are an essential part of cardiac assistance. Synchronization of the counterpulsation CAD controller with the cardiac cycle is critical to the efficacy of the CAD. The robustness of counterpulsation CAD controllers varies with the ability of the CAD controller to properly trigger on aortic pressure (Pa) and electrocardiogram (ECG) signals for sinusoid rhythms, non-sinusoid rhythms and non-ideal signals resulting from surgical intervention. An analog-to-digital converter and digital-to-analog converter based CAD controller development platform was devised on a 33Mhz PC-AT.

Counterpulsation Pa systolic rise and dicrotic notch detectors were demonstrated with a …

Non-Linear Evaluation Of Concrete-Filled Steel Tubular Columns, Mohammad Hassan Shams

Dissertations

Concrete-filled steel tubular (CFT) columns have become increasingly popular in structural applications due to their high strength, high ductility, and large energy absorption capacity. These structural properties are the result of integral behavior of the concrete core and the steel tube. This research provides an analysis of the interaction of the concrete core and the steel tube in CFT columns.

While there have been many experimental studies of CFT columns, there has been no analytical work modeling the confining effect of the steel tube on the concrete core. Furthermore, current design procedures tend to underestimate the ultimate strengths of CFTs …

Shaped Charges Having A Porous Tungsten Liner-An Experimental And Theoretical Study Of Metal Compression, Jet Formation And Penetration Mechanics, Brian Edward Fuchs

Dissertations

The use of porous tungsten as a liner for shaped charges to improve their penetration was proposed by Ki-Hwan Oh in his invention disclosure "Shock Extrusion of Ingots from Powders or Solids", at the New Mexico Institute of Mining and Technology, Socorro NM on June 7, 1988. The intention was to increase the ductility of the normally brittle metal by heating the liner to a high temperature by shock compaction during its acceleration just before jet formation.

The feasibility of increasing the ductility of tungsten in this way is the subject of the present study. The theory and prior experimental …

Performance Evaluation Of Cebus Power Line Communication In The Presence Of X-10 Module Signaling, Nashwa F. Kamel

Theses

A power line of CEBus has great potential towards inexpensive home automation. Both PLBus and X-10 uses [sic] burst of 120KHz signals to transmit bits of information on the power line. However, these two systems are completely incompatible and can conflict with each other. This thesis presents the first performance evaluation of Power Line CEBus communication in the presence of X-10 module signaling. The evaluation included simulation experiments measuring packet delays, message delays, message throughput, channel throughput and the percentage of messages received in error verses [sic] different loads. Network performance has been confirmed to function well in terms of …

Measuring The Need For Manufacturing Flexibility And Evaluating Its Economic Benefits, Navin Karwande

Theses

Flexible systems are known of enabling organizations to take advantage of diversified products, low volume production items with short life-cycles. They also improve the ability to respond to market changes. Flexibility has thus become a strategic manufacturing need in recent years.

Because of the high initial capital outlay involved, the selection of the appropriate flexible solution has become a critical issue. This thesis proposes a methodology to determine the most cost effective and feasible flexibility strategy. A flexibility audit is developed to analyze and evaluate the changes taking place in a facility's environment. These changes and a measurement scheme is …

Trifluoroiodomethane As An Environmentally Friendly Gas For Water Patterning By Plasma Etching Process, Krit Aryusook

Theses

Trifluoroiodomethane (CF₃I), a non-global warming gas, has been investigated with study as a substitute for typical CFC etchants, such as CF₄ and C₂F₆, used in wafer pattering technology. This investigation was carried out by exposing dielectric films of silicon oxide (SiO₂) and silicon nitride (Si₃N₄) in CF₃I and C₂F₆/O₂ (used as a reference) plasma environments. The etch rate of these films was ascertained as function of applied rf power, etchant gas flow rate, reaction chamber operating pressure, and O_{2 …}

Design, Simulation And Fabrication Of A Mems In-Situ Contactless Sensor To Detect Plasma Induced Damage During Reactive Ion Etching, Subramanian Ganesh

Theses

The present trend in the semiconductor industry is towards submicron devices. An inevitable process technique in achieving this is by reactive ion etching of the polysilicon gate. During RIE, the gate oxide may get damaged due to several causes. One of the main causes of the damage is the non-uniformity of the plasma. It is reported that these plasma inconsistencies are mainly due to electrode design and that they create spatial plasma potential fluctuation. These fluctuations are reported to be in the range of 10-20 Volts. By providing an in-situ monitoring of the wafers, the reliability of the device could …

Modeling Of Objects Using Planar Facets In Noisy Range Images, Girish Phansalkar

Theses

Products designed and manufactured before the advent of Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) technology have not been documented electronically. To avoid the laborious procedure of redesigning the parts, a reverse engineering approach can be adopted. This approach involves, taking a picture of the object and constructing a solid model from the image data.

Range image is a three dimensional image of an object or a scene. This image can be obtained from special cameras, called range image cameras, or can be constructed from the Coordinate Measuring Machine's (CMM) output data. Adaptive Fuzzy c-Elliptotype (AFC) clustering algorithm …

Synthesis And Characterization Of Hafnium Carbide Thin Films, Wiriya Thongruang

Theses

Hafnium carbide thin films of various characteristics were deposited on silicon substrates using dc magnetron sputtering. A HfC target was used as a sputtering source and Ar was used as a sputtering gas during deposition. The variables investigated were total sputtering gas pressure and power. Optimum characteristics were achieved with a total sputtering gas pressure of 5 mTorr and power of 200 W. No evidence for oxidation of the film was found at a depth below 400A for deposited and annealed films. Binding characteristics were obtained from ESCA data. The compressive film stress increased when sputtering gas pressure decreased. The …

Relaxation And The Nature Of Electrical Stress Related Defects In Ultra-Thin Dioxide On Silicon, Lihui Xie

Theses

The instability of defects created in ultra-thin insulator, metal-oxide-silicon devices biased in the direct tunnel regime is investigated. For the case of electron injection from the silicon substrate, nearly complete defect relaxation is observed after the bias is removed, allowing the possibility of re-generating the defects. Modeling the defect generation process and examining differences between initial and subsequent degradation periods lead to an improved picture of both the relaxation process and the nature of the involved defects.

Potential Effects Of Pneumatic Fracturing On Existing Structures And Utilities, Michael C. Canino

Theses

This thesis develops a mathematical design model for predicting ground deformations resulting from pneumatic fracturing. Pneumatic fracturing is a patented process developed for the purpose of enhancing the in situ treatment and removal of hazardous contaminants from geologic formations. During pneumatic injections, measurable ground deformations are experienced both during and after the process. Safe application of pneumatic fracturing to contaminated plumes occurring beneath existing structures and utilities requires that the elastic deformation behavior of the geologic formation and overlying structures be quantified.

Data from five pneumatic fracturing sites were regressed to establish the characteristic polynomial describing the curvature of ground …

Design Of A Mode Of Delivery For Macrobead Transplantation, Jagdip Desai

Theses

The macrobead is a form of a biohybrid artificial pancreas (BAP), which is being developed to treat type 1 diabetes. A hypothetical human transplant would require 125 rat equivalent macrobeads. For intraperitoneal transplantation a mode of delivery that allows the placement of several hundred macrobeads into a basket or pouch type device is required.

In this study, four commercially available materials were studied as possible candidates for creating a pouch. These materials are polyvinyl chloride acrylic copolymer (PVC), polyethersulfone (PES), polyvinylidenedifluoride (PVDF), and polytetrafluorethylene (PTFE). Tubular pouches of each material were designed. They then underwent in vivo biocompatibility and in-vitro …

A Cost Model For Multi-Lifecycle Engineering Design, Bin Zhang

Theses

Design for Environment aims to yield a product whose aggregate environmental impact is as small as possible. This thesis characterizes a product recovery system and defines the concepts of product lifetime and part lifetime. A multi-lifecycle product recovery model is developed based on the concepts of product tree and disassembly path representation, four product recovery choices, time varying costs, cost comparison. The four product recovery choices of a part in the product tree are: Reconditioning, Part Remanufacturing, Material Recycling, and Landfill. This thesis focuses on how to improve the product design while minimizing environmental impact of the product and introduces …

Microporous Silicon Dioxide/Vycor Membranes For Gas Separation, Justin R. Barone

Theses

This study focused on producing membranes for molecular sieving of gases by reducing the pore size of an already existing membrane structure. To do this, SiO₂ was deposited inside the pores of a Vycor tube with initial pore diameter of 4 nm. The film deposition took place by a low pressure chemical vapor deposition (LPCVD) process where diethylsilane (DES) and nitrous oxide (N₂O) were used as precursor gases. A counterflow reactant geometry was used where the precursor gases were flowed on both sides of the porous membrane. This deposition geometry gave higher selectivities and better mechanical stability. …