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open access

Shear and Bending Strength of Cold-Formed Steel Solid Wall Panels Using Corrugated Steel Sheets for Mobile Shelters

Description: The objective of this thesis is to determine if the single sided resistance spot weld (RSW) can be used as a feasible connection method for cold formed steel (CFS) shear walls subject to lateral force of either seismic or wind loads on mobile shelters. The research consisted of three phases which include: a design as a 3D BIM model, connection tests of the resistance spot weld, and full-scale testing of the designed solid wall panels. The shear wall testing was conducted on specimens with both … more
Date: December 2017
Creator: Derrick, Nathan Lynn
Partner: UNT Libraries
open access

Shear and Compression Strength of Cold-formed Steel Clip Angles Subjected to Different Screw Patterns

Description: This thesis presents experiments and numerical analysis of the cold-formed steel clip angle in three different limit states which are shear, compression, and combination of the screw connection. A previous cold-formed steel clip angle test program (which is Phase 1) developed design methods for clip angle. Therefore, the object of this thesis is to further investigate the behavior and design methods of loading-bearing cold-formed steel clip angles under different screw pattern. For each limit … more
Date: December 2017
Creator: Yan, Zhishan
Partner: UNT Libraries

Development of a Coaxiality Indicator

Description: The geometric dimensioning and tolerancing concept of coaxiality is often required by design engineers for balance of rotating parts and precision mating parts. In current practice, it is difficult for manufacturers to measure coaxiality quickly and inexpensively. This study examines feasibility of a manually-operated, mechanical device combined with formulae to indicate coaxiality of a test specimen. The author designs, fabricates, and tests the system for measuring coaxiality of holes machine… more
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Date: December 1999
Creator: Arendsee, Wayne C.
Partner: UNT Libraries
open access

Effects of a Surface Engineered Metallic Coating on Elastomeric Valve Stem Seal Leakage

Description: Valve stem seal leakage is a major source of fugitive emissions, and controlling these emissions can result in added expense in leak detection and repair programs. Elastomeric O-rings can be used as valve stem seals, and O-ring manufacturers recommend lubrication of elastomeric seals to prevent damage and to assure proper sealing. In this research, a metallic coating was applied as a lubricant using a vacuum vapor deposition process to the surface of elastomeric valve stem seals. Valve stem le… more
Date: December 2000
Creator: Taylor, John Abner
Partner: UNT Libraries

Effect of Engineered Surfaces on Valve Performance

Description: Performance of air operated valves is a major maintenance concern in process industries. Anecdotal information indicates that reliability of some high maintenance valves has been improved by using an ion deposition process to achieve engineered surfaces on selected components. This project compared friction for various surface treatments of selected valve components. Results indicate valve performance may be slightly more consistent when an engineered surface is applied in the valve packing are… more
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Date: December 2000
Creator: Pope, Larry G.
Partner: UNT Libraries
open access

Fracture Toughness Testing of Plastics under Various Environmental Conditions

Description: The primary objective of this study is to test the applicability to plastics of a fracture toughness testing tool developed for metals. The intent is to study pre-test conditioning of several plastic materials and the effect of the depth of the razor notch cut in the chevron notched fracture toughness test specimens. The study includes the careful preparation of samples followed by conditioning in various environments. Samples were subjected to laboratory air for a specific duration or to a con… more
Date: December 1997
Creator: Velpuri, Seshagirirao V.
Partner: UNT Libraries
open access

Investigation of the feasibility of non-invasive carbon dioxide detection using spectroscopy in the visible spectrum.

Description: Pulse oximeters are used in operating rooms and recovery rooms as a monitoring device for oxygen in the respiratory system of the patient. The advantage of pulse oximeters over other methods of oxygen monitoring is that they are easy to use and they are non-invasive, which means it is not necessary break the skin to extract blood for information to be obtained. The standard for the measurement of partial pressure of CO2 and O2 is an arterial blood gas analysis (ABG). However routine monitoring … more
Date: December 2007
Creator: Marks, Damian
Partner: UNT Libraries
open access

Cost Savings Realized Through Proper Sizing of an Excessive Instrument Air System.

Description: The purpose of this research was to determine if installing a smaller air compressor could reduce the electrical usage of a large semiconductor manufacturing plant. A 200 horsepower Atlas Copco compressor was installed with the existing 500 horsepower Ingersoll-Rand compressors. Testing was conducted during the regular manufacturing process at MEMC Southwest in Sherman, Texas. Analysis of the data found that installing the new compressor could reduce electrical consumption. The study also found… more
Date: December 2003
Creator: Condron, Ewell D.
Partner: UNT Libraries
open access

Effect of Amines as Corrosion Inhibitors for a Low Carbon Steel in Power Industry

Description: Commonly used amines in power industry, including morpholine, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), and DMA (dimethylallylamine) were evaluated for their effect on AISI 1018 steel at 250oF. Samples were exposed to an autoclave containing amine added aqueous solution at pH of 9.5 for 1, 2, 4, 6, 8, and 12 hours. Morphology studies were carried using scanning electron microscope (SEM), phase analysis was done utilizing Fourier transform infrared spectroscopy (FTIR), and weight loss was perfor… more
Date: December 2004
Creator: Díaz, Jorge G.
Partner: UNT Libraries
open access

Computer Virus Spread Containment Using Feedback Control.

Description: In this research, a security architecture based on the feedback control theory has been proposed. The first loop has been designed, developed and tested. The architecture proposes a feedback model with many controllers located at different stages of network. The controller at each stage gives feedback to the one at higher level and a decision about network security is taken. The first loop implemented in this thesis detects one important anomaly of virus attack, rate of outgoing connection. Tho… more
Date: December 2004
Creator: Yelimeli Guruprasad, Arun
Partner: UNT Libraries

Development of a Hybrid Molecular Ultraviolet Photodetector based on Guanosine Derivatives

Description: Modern studies on charge transfer reaction and conductivity measurements of DNA have shown that the electrical behavior of DNA ranges from that of an insulator to that of a wide bandgap semiconductor. Based on this property of DNA, a metal-semiconductor-metal photodetector is fabricated using a self-assembled layer of deoxyguanosine derivative (DNA base) deposited between gold electrodes. The electrodes are lithographically designed on a GaN substrate separated by a distance L (50nm < L < 100nm… more
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Date: December 2005
Creator: Liddar, Harsheetal
Partner: UNT Libraries

Surface Plasmon Based Nanophotonic Optical Emitters

Description: Group- III nitride based semiconductors have emerged as the leading material for short wavelength optoelectronic devices. The InGaN alloy system forms a continuous and direct bandgap semiconductor spanning ultraviolet (UV) to blue/green wavelengths. An ideal and highly efficient light-emitting device can be designed by enhancing the spontaneous emission rate. This thesis deals with the design and fabrication of a visible light-emitting device using GaN/InGaN single quantum well (SQW) system wit… more
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Date: December 2005
Creator: Vemuri, Padma Rekha
Partner: UNT Libraries

Evaluation of dynamic and static electrical characteristics for the DY8 and YI8 process gallium diodes in comparison to the DI8 process boron diodes.

Description: A rectifier is an electrical device, comprising one or more semiconductor devices arranged for converting alternating current to direct current by blocking the negative or positive portion of the waveform. The purpose of this study would be to evaluate dynamic and static electrical characteristics of rectifier chips fabricated with (a) DY8 process and (b) YI8 process and compare them with the existing DI8 process rectifiers. These new rectifiers were tested to compare their performance to meet … more
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Date: December 2006
Creator: Dhoopati, Swathi
Partner: UNT Libraries
open access

Radio frequency propagation differences through various transmissive materials.

Description: The purpose of this research was to determine which of the commonly used wireless telecommunication site concealment materials has the least effect on signal potency. The tested materials were Tuff Span® fiberglass panels manufactured by Enduro Composite Systems, Lexan® XL-1 polycarbonate plastic manufactured by GE Corporation and Styrofoam™ polystyrene board manufactured by The Dow Chemical Company. Testing was conducted in a double electrically isolated copper mesh screen room at the Univer… more
Date: December 2002
Creator: Ryan, Patrick L.
Partner: UNT Libraries
open access

Study of the Corrosion Resistance of 316L Stainless Steel Made by Directed Energy Deposition for Applications at an Elevated Temperature

Description: The corrosion resistance under elevated temperature of additively manufactured 316L stainless steel made by directed energy deposition was studied. Test samples were prepared in a hybrid additive manufacturing machine using standard deposition parameters recommended by the manufacturer. Control samples were cut from wrought material to compare the results. The test was performed under a corrosive atmosphere with a solution of water with 3.5 % in weight of salt (NaCl). The total duration of the … more
Date: December 2021
Creator: Canales Cantu, Alberto Alejandro
Partner: UNT Libraries
open access

Susceptibility of a digital turbine control system to IEEE 802.11 compliant emissions.

Description: Within the nuclear industry, there have been numerous instances of radio transmissions interfering with sensitive plant equipment. Instances documented vary from minor instrument fluctuations to major plant transients including reactor trips. With the nuclear power industry moving toward digital technologies for control and reactor protection systems, concern exists regarding their potential susceptibility to contemporary wireless telecommunications technologies. This study evaluates the suscep… more
Date: December 2003
Creator: Carter, Clinton E.
Partner: UNT Libraries
open access

Indoor Propagation Modeling at 2.4 GHz for IEEE 802.11 Networks

Description: Indoor use of wireless systems poses one of the biggest design challenges. It is difficult to predict the propagation of a radio frequency wave in an indoor environment. To assist in deploying the above systems, characterization of the indoor radio propagation channel is essential. The contributions of this work are two-folds. First, in order to build a model, extensive field strength measurements are carried out inside two different buildings. Then, path loss exponents from log-distance path l… more
Date: December 2005
Creator: Tummala, Dinesh
Partner: UNT Libraries

Construction Management Methods and Techniques in Army Tactical Shelter

Description: This thesis presents a research effort aimed at developing using construction methods and techniques in army tactical shelter. The beginning step focuses on developing and identifying different activities and work breakdown structure applicable in shelter prototype. The next step focuses on identifying resource allocation. This include allocate resources based on the delivered project as per alternative one and for the second alternative as optimization, resource allocation modified and tried t… more
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Date: December 2019
Creator: Yeganehtalab, Babak
Partner: UNT Libraries
open access

Fabrication and Testing of Biomimetic Microstructures for Walkway Tribometers

Description: The main objective of this work is to give contribution in both additive manufacturing (AM) and tribometry derived from the application and study of materials available with the use of biomimetic designs. Additional contributions are determining what effects treatments for flooring surfaces may have on the dynamic coefficient of friction and the effects of these products on common surfaces. The validity of the proposed methodology for a proof of concept was demonstrated by comparing measured dy… more
Date: December 2019
Creator: Haney, Christopher Willard
Partner: UNT Libraries

Design Method of Cold-Formed Steel Framed Shear Wall Sheathed by Structural Concrete Panel

Description: The objective of this research is developing a new method of design for cold-formed steel framed shear wall sheathed by ¾" thick USG structural panel concrete subfloor using a predictive analytical model and comparing the results obtained from the model with those achieved from real testing to verify the analytical model and predicted lateral load-carrying capacity resulted from that. Moreover, investigating the impact of various screw spacings on shear wall design parameter such as ultimate st… more
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Date: December 2019
Creator: Ashkanalam, Aida
Partner: UNT Libraries
open access

Microfluidic-Based Fabrication of Photonic Microlasers for Biomedical Applications

Description: Optical microlasers have been used in different engineering fields and for sensing various applications. They have been used in biomedical fields in applications such as for detecting protein biomarkers for cancer and for measuring biomechanical properties. The goal of this work is to propose a microfluidic-based fabrication method for fabricating optical polymer based microlasers, which has advantages, over current methods, such us the fabrication time, the contained cost, and the reproducibil… more
Date: December 2019
Creator: Cavazos, Omar
Partner: UNT Libraries
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