UNT Theses and Dissertations - 62 Matching Results

Search Results

prev Results: 11 - 34 next

Cold-Formed Steel Member Connections Using BAC Screw Fasteners

Description: In this project, the main research objective is intend to seek criteria for evaluating the capacity of BAC screw fasteners with mixed configuration of waterproof seal washer, sealer tape and different pre-drill holes to determine shear and tension strength values for the screws used in cold-formed steel connections. The thesis presents the design methods and test program conducted to investigate the behavior and strength of the screw connections in shear and tension test. Test results were comp… more
Access: Restricted to UNT Community Members. Login required if off-campus.
Date: May 2019
Creator: Li, Xun
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Topology and Lattice-Based Structural Design Optimization for Additively Manufactured Medical Implants

Description: Topology-based optimization techniques and lattice structures are powerful ways to accomplish lightweight components with enhanced mechanical performance. Recent developments in additive manufacturing (AM) have led the way to extraordinary opportunities in realizing complex designs that are derived from topology and lattice-based structural optimization. The main aim of this work is to give a contribution, in the integration between structural optimization techniques and AM, by proposing a setu… more
Date: May 2019
Creator: Peto, Marinela
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Hydrophobicity of Magnetite Coating on Low Carbon Steel

Description: Superhydrophobic coatings (SHC) with excellent self-cleaning and corrosion resistance property is developed on magnetite coated AISI SAE 1020 steel by using a simple immersion method. Roughness measurement, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), contact angle measurement (CAM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS), … more
Date: August 2018
Creator: Akhtar, Mst Alpona
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Design and Development of Lightweight Composite Wall, Roof, and Floor Panels for Rigid Wall Shelter

Description: This thesis presents a research effort aimed at developing a stronger, lighter, and more economic shelter using rigid wall panels. Reported herein is insulation research, wall and roof panel design and testing, floor section modeling and strength calculations, and cost and weight calculations. Beginning stages focus on developing solid wall and roof panels using cold-formed steel corrugated sheathing and members, as well as polyurethane spray foam for insulation. This research includes calculat… more
Date: May 2018
Creator: Artman, Jeremy J
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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
Item Type: Refine your search to only Thesis or Dissertation
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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of Immersion Cooled ARM-Based Computer Clusters for Low-Cost, High-Performance Computing

Description: This study aimed to investigate performance of ARM-based computer clusters using two-phase immersion cooling approach, and demonstrate its potential benefits over the air-based natural and forced convection approaches. ARM-based clusters were created using Raspberry Pi model 2 and 3, a commodity-level, single-board computer. Immersion cooling mode utilized two types of dielectric liquids, HFE-7000 and HFE-7100. Experiments involved running benchmarking tests Sysbench high performance linpack (H… more
Date: August 2017
Creator: Mohammed, Awaizulla Shareef
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Seismic Performance Evaluation of Novel Cold-Formed Steel Framed Shear Walls Sheathed with Corrugated Steel Sheets

Description: This thesis presents experiments and numerical analysis of a novel cold-formed steel framed shear wall sheathed with corrugated steel sheets. The objective of this newly designed shear wall is to meet the growing demand of mid-rise buildings and the combustibility requirement in the International Building Code. The strength of the novel shear wall is higher than currently code certified shear wall in AISI S400-15 so that it could be more favorable for mid-rise building in areas that are prone t… more
Date: August 2017
Creator: Lan, Xing
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Two-Phase Spray Cooling with HFC-134a and HFO-1234yf for Thermal Management of Automotive Power Electronics using Practical Enhanced Surfaces

Description: The objective of this research was to investigate the performance of two-phase spray cooling with HFC-134a and HFO-1234yf refrigerants using practical enhanced heat transfer surfaces. Results of the study were expected to provide a quantitative spray cooling performance comparison with working fluids representing the current and next-generation mobile air conditioning refrigerants, and demonstrate the feasibility of this approach as an alternative active cooling technology for the thermal manag… more
Date: August 2017
Creator: Altalidi, Sulaiman Saleh
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Design, Modeling, and Experiment of a Piezoelectric Pressure Sensor based on a Thickness-Shear Mode Crystal Resonator

Description: This thesis presents the design, modeling, and experiment of a novel pressure sensor using a dual-mode AT-cut quartz crystal resonator with beat frequency analysis based temperature compensation technique. The proposed sensor can measure pressure and temperature simultaneously by a single AT-cut quartz resonator. Apart from AT-cut quartz crystal, a newly developed Langasite (LGS) crystal resonator is also considered in the proposed pressure sensor design, since LGS can operate in a higher tempe… more
Date: May 2017
Creator: Pham, Thanh Tuong
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of Spray Cooling Schemes for Dynamic Thermal Management

Description: This study aims to investigate variable flow and intermittent flow spray cooling characteristics for efficiency improvement in active two-phase thermal management systems. Variable flow spray cooling scheme requires control of pump input voltage (or speed), while intermittent flow spray cooling scheme requires control of solenoid valve duty cycle and frequency. Several testing scenarios representing dynamic heat load conditions are implemented to characterize the overall performance of variable… more
Date: May 2017
Creator: Yata, Vishnu Vardhan Reddy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Study on the System Reliability of Cold-Formed Steel Roof Trusses

Description: This thesis presents a research project aimed at advancing the treatment of cold-formed steel (CFS) structural reliability in roof trusses. Structural design today relies almost exclusively on component-level design, so structural safety is assured by limiting the probability of failure of individual components. Reliability of the entire system is typically not assessed, so in a worst-case scenario the system reliability may be less than the component reliability, or in a best-case scenario the… more
Date: May 2017
Creator: Johnson, Adam M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Study of the Synthesis and Surface Modification of UV Emitting Zinc Oxide for Bio-Medical Applications

Description: This thesis presents a novel ZnO-hydrogel based fluorescent colloidal semiconductor nanomaterial system for potential bio-medical applications such as bio-imaging, cancer detection and therapy. The preparation of ZnO nanoparticles and their surface modification to make a biocompatible material with enhanced optical properties is discussed. High quality ZnO nanoparticles with UV band edge emission are prepared using gas evaporation method. Semiconductor materials including ZnO are insoluble in w… more
Date: May 2009
Creator: John, Sween
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Flow Accelerated Corrosion Experience at Comanche Peak Steam Electric Station

Description: Flow accelerated corrosion (FAC) is a major concern in the power industry as it causes thinning of the pipes by the dissolution of the passive oxide layer formed on the pipe surface. Present research deals with comparing the protection offered by the magnetite (Fe3O4) versus maghemite (γ-Fe2O3) phases thickness loss measurements. Fourier transform infrared spectroscopy (FTIR) is used in distinguishing these two elusive phases of iron oxides. Representative pipes are collected from high pressure… more
Date: May 2008
Creator: Nakka, Ravi Kumar
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Liquid Nitrogen Propulsion Systems for Automotive Applications: Calculation of Mechanical Efficiency of a Dual, Double-acting Piston Propulsion System

Description: A dual, double-acting propulsion system is analyzed to determine how efficiently it can convert the potential energy available from liquid nitrogen into useful work. The two double-acting pistons (high- and low-pressure) were analyzed by using a Matlab-Simulink computer simulation to determine their respective mechanical efficiencies. The flow circuit for the entire system was analyzed by using flow circuit analysis software to determine pressure losses throughout the system at the required mas… more
Date: May 2008
Creator: North, Thomas B.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Study of Laser Direct Writing for All Polymer Single Mode Passive Optical Channel Waveguide Devices

Description: The objective of this research is to investigate the use of laser direct writing to micro-pattern low loss passive optical channel waveguide devices using a new hybrid organic/inorganic polymer. Review of literature shows previous methods of optical waveguide device patterning as well as application of other non-polymer materials. System setup and design of the waveguide components are discussed. Results show that laser direct writing of the hybrid polymer produce single mode interconnects w… more
Date: May 2008
Creator: Borden, Bradley W.
Item Type: Refine your search to only Thesis or Dissertation
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
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Characterization of Boron Nitride Thin Films on Silicon (100) Wafer.

Description: Cubic boron nitride (cBN) thin films offer attractive mechanical and electrical properties. The synthesis of cBN films have been deposited using both physical and chemical vapor deposition methods, which generate internal residual, stresses that result in delamination of the film from substrates. Boron nitride films were deposited using electron beam evaporation without bias voltage and nitrogen bombardment (to reduce stresses) were characterize using FTIR, XRD, SEM, EDS, TEM, and AFM technique… more
Date: August 2007
Creator: Maranon, Walter
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

FPGA Prototyping of a Watermarking Algorithm for MPEG-4

Description: In the immediate future, multimedia product distribution through the Internet will become main stream. However, it can also have the side effect of unauthorized duplication and distribution of multimedia products. That effect could be a critical challenge to the legal ownership of copyright and intellectual property. Many schemes have been proposed to address these issues; one is digital watermarking which is appropriate for image and video copyright protection. Videos distributed via the Inter… more
Date: May 2007
Creator: Cai, Wei
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Preliminary design of a cryogenic thermoelectric generator.

Description: A cryogenic thermoelectric generator is proposed to increase the efficiency of a vehicle propulsion system that uses liquid nitrogen as its fuel. The proposed design captures some of the heat required for vaporizing or initial heating of the liquid nitrogen to produce electricity. The thermoelectric generator uses pressurized liquid nitrogen as its cold reservoir and ambient air as the high-temperature reservoir to generate power. This study concentrated on the selection of thermoelectric mater… more
Date: May 2007
Creator: Sivapurapu, Sai Vinay Kumar
Item Type: Refine your search to only Thesis or Dissertation
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
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2006
Creator: Dhoopati, Swathi
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

MBE Growth and Instrumentation

Description: This thesis mainly aims at application of principles of engineering technology in the field of molecular beam epitaxy (MBE). MBE is a versatile technique for growing epitaxial thin films of semiconductors and metals by impinging molecular beams of atoms onto a heated substrate under ultra-high vacuum (UHV) conditions. Here, a LabVIEW® (laboratory virtual instrument engineering workbench) software (National Instruments Corp., http://www.ni.com/legal/termsofuse/unitedstates/usH) program is dev… more
Date: May 2006
Creator: Tarigopula, Sriteja
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Propagation analysis of a 900 MHz spread spectrum centralized traffic signal control system.

Description: The objective of this research is to investigate different propagation models to determine if specified models accurately predict received signal levels for short path 900 MHz spread spectrum radio systems. The City of Denton, Texas provided data and physical facilities used in the course of this study. The literature review indicates that propagation models have not been studied specifically for short path spread spectrum radio systems. This work should provide guidelines and be a useful ex… more
Date: May 2006
Creator: Urban, Brian L.
Item Type: Refine your search to only Thesis or Dissertation
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
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: December 2005
Creator: Liddar, Harsheetal
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
Back to Top of Screen