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open access

Hardware and Software Codesign of a JPEG2000 Watermarking Encoder

Description: Analog technology has been around for a long time. The use of analog technology is necessary since we live in an analog world. However, the transmission and storage of analog technology is more complicated and in many cases less efficient than digital technology. Digital technology, on the other hand, provides fast means to be transmitted and stored. Digital technology continues to grow and it is more widely used than ever before. However, with the advent of new technology that can reproduce d… more
Date: December 2008
Creator: Mendoza, Jose Antonio
open access

Innovative Cold-Formed Steel Shear Walls with Corrugated Steel Sheathing

Description: This thesis presents two major sections with the objective of introducing a new cold-formed steel (CFS) shear wall system with corrugated steel sheathings. The work shown herein includes the development of an optimal shear wall system as well as an optimal slit configuration for the CFS corrugated sheathings which result in a CFS shear wall with high ductility, high strength, high stiffness and overall high performance. The conclusion is based on the results of 36 full-scale shear wall tests pe… more
Date: May 2016
Creator: Mahdavian, Mahsa
open access

Accelerated Corrosion Test with Operation Simulation of All-Aluminum Microchannel Heat Exchangers

Description: The HVAC&R industry is looking to transition from copper-aluminum heat exchangers to all-aluminum microchannel technology. The want for the transition stemmed from seeing the performance improvement of all-aluminum microchannel radiators in the automotive industry. Applications differ between the two industries; therefore, applying this technology for HVAC&R use must be validated. Research towards operating modes of an all-aluminum heat exchanger in a defined corrosive environment will provide … more
Date: May 2016
Creator: Vaughan, Haydn
open access

Knowledge Based System and Decision Making Methodologies in Materials Selection for Aircraft Cabin Metallic Structures

Description: Materials selection processes have been the most important aspects in product design and development. Knowledge-based system (KBS) and some of the methodologies used in the materials selection for the design of aircraft cabin metallic structures are discussed. Overall aircraft weight reduction means substantially less fuel consumption. Part of the solution to this problem is to find a way to reduce overall weight of metallic structures inside the cabin. Among various methodologies of materials … more
Date: August 2016
Creator: Adhikari, Pashupati Raj
open access

Two-Phase Spray Cooling with Water/2-Propanol Binary Mixtures for High Heat Flux Focal Source

Description: Two-phase spray cooling has been an emerging thermal management technique offering high heat transfer coefficients and critical heat flux levels, near-uniform surface temperatures, and efficient coolant usage that enables to design of compact and lightweight systems. Due to these capabilities, spray cooling is a promising approach for high heat flux applications in computing, power electronics, and optics. Two-phase spray cooling inherently depends on saturation temperature-pressure relations… more
Date: December 2016
Creator: Obuladinne, Sai Sujith
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
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
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
open access

A Computer-Based Process Control System for a Target Station in a LINAC Facility

Description: An event-driven, sequential, process control system was designed for International Isotopes, Inc., to automate and remotely control a target station at the company's linear accelerator facility. The designed system consisted of two major sections: a software program (virtual instrument), which was developed by LabVIEW, and a hardware interface (FieldPoint Modular Distributed I/O System by National Instrument), which had to be a pre-developed system that did not require customization. The design… more
Date: May 1999
Creator: Al-Shantaf, Abdulraouf O.
open access

Development of a Simplified Fracture Toughness Tool for Polymers

Description: This thesis presents research toward the development of a simple inexpensive fracture toughness tool for polymeric materials. Experiments were conducted to test the specimen configuration and the fracture toughness tool against an established ASTM standard for polymer fracture toughness, D5045, and a commonly used four-point bend method. The materials used in this study were polycarbonate and high density polyethylene. Reductions in both the production time and the variability resulting from th… more
Date: August 1997
Creator: Marnock, Patrick J. (Patrick Joseph)
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.
open access

A Data Acquisition System Experiment for Gas Temperature and Pressure Measurements on a Liquid-Nitrogen-Powered Vehicle

Description: A data acquisition system was set up to measure gas temperatures and pressures at various points on a liquid-nitrogen-powered vehicle. The experiment was attempted to develop a data acquisition method for applications on engines that use liquid air as the fuel. Two thermocouples and a pressure transducer were connected using data acquisition instruments interfaced to a laptop computer to acquire data.
Date: May 1998
Creator: Lui, Samson Sze-Sang
open access

Laser Cutting Machine: Justification of initial costs

Description: The Industrial Laser is firmly established in metalcutting as the tool of choice for many applications. The elevator division of Montgomery KONE Inc., in an effort to move towards quality, ontime, complete deliveries and 100% customer satisfaction, decided to invest in new equipment to improve manufacturing processes. A huge investment is proposed for a laser-cutting machine. It is the responsibility of Manufacturing Engineering to direct the management by justifying its benefits, which include… more
Date: May 2001
Creator: Nagaraja, Dwarakish
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
open access

Determination of the Shelf Life of Aluminum Electrolytic Capacitors.

Description: The aluminum electrolytic capacitor is used extensively in the electric utility industry. A factor limiting the storage of spare capacitors is the integrity of the aluminum oxide dielectric, which over time breaks down contributing to a shelf life currently estimated at one nuclear power electric generating station to be approximately five years. This project examined the electrical characteristics of naturally aged capacitors of several different styles to determine if design parameters were… more
Date: May 2002
Creator: Wynne, Edward McFaddin
open access

Effects of Rebar Temperature and Water to Cement Ratio on Rebar-Concrete Bond Strength of Concrete Containing Fly Ash

Description: This research presents the results on an experimental investigation to identify the effects of rebar temperature, fly ash and water to cement ratio on concrete porosity in continuously reinforced concrete pavements (CRCP). Samples were cast and analyzed using pullout tests. Water to cement ratio (w/c) and rebar temperature had a significant influence on the rebar-concrete bond strength. The 28-day shear strength measurements showed an increase in rebar-concrete bond strength as the water to cem… more
Date: May 2010
Creator: Pati, Ardeep Ranjan
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.

Effects of Thickness and Indenter Tip Geometry in Nanoindentation of Nickel Films

Description: Nanoindentation has become a widely used technique to measure the mechanical properties of materials. Due to its capability to deform materials in micro- and nano-scale, nanoindentation has found more applications in characterizing the deformation behavior and determining the mechanical properties of thin films and coatings. This research deals with the characterization of samples received from Center for Advanced Microstructures and Devices (CAMD) and Integran Technologies Inc., Toronto, Canad… more
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Date: May 2004
Creator: Parakala, Padma

Design of Power Amplifier Test Signals with a User-Defined Multisine

Description: Cellular radio communication involves wireless transmission and reception of signals at radio frequencies (RF). Base stations house equipment critical to the transmission and reception of signals. Power amplifier (PA) is a crucial element in base station assembly. PAs are expensive, take up space and dissipate heat. Of all the elements in the base station, it is difficult to design and operate a power amplifier. New designs of power amplifiers are constantly tested. One of the most important co… more
Access: Restricted to UNT Community Members. Login required if off-campus.
Date: May 2004
Creator: Nagarajan, Preeti
open access

Sunlight readability and luminance characteristics of light-emitting diode push button switches.

Description: Lighted push button switches and indicators serve many purposes in cockpits, shipboard applications and military ground vehicles. The quality of lighting produced by switches is vital to operators' understanding of the information displayed. Utilizing LED technology in lighted switches has challenges that can adversely affect lighting quality. Incomplete data exists to educate consumers about potential differences in LED switch performance between different manufacturers. LED switches from four… more
Date: May 2004
Creator: Fitch, Robert J.
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.
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
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

Synthesis of cubic boron nitride thin films on silicon substrate using electron beam evaporation.

Description: Cubic boron nitride (cBN) synthesis has gained lot of interest during the past decade as it offers outstanding physical and chemical properties like high hardness, high wear resistance, and chemical inertness. Despite of their excellent properties, every application of cBN is hindered by high compressive stresses and poor adhesion. The cost of equipment is also high in almost all the techniques used so far. This thesis deals with the synthesis of cubic phase of boron nitride on Si (100) wafers … more
Access: Restricted to the UNT Community Members at a UNT Libraries Location.
Date: May 2004
Creator: Vemuri, Prasanna
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