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Feasibility Study of Consolidation by Direct Compaction and Friction Stir Processing of Commercially Pure Titanium Powder

Description: Commercially pure titanium can take up to six months to successfully manufacture a six-inch in diameter ingot in which can be shipped to be melted and shaped into other useful components. The applications to the corrosion-resistant, light weight, strong metal are endless, yet so is the manufacturing processing time. At a cost of around $80 per pound of certain grades of titanium powder, the everyday consumer cannot afford to use titanium in the many ways it is beneficial simply because the numb… more
Date: August 2016
Creator: Nichols, Leannah Marie
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Dissimilar Friction Stir Welding Between Magnesium and Aluminum Alloys

Description: Joining two dissimilar metals, specifically Mg and Al alloys, using conventional welding techniques is extraordinarily challenging. Even when these alloys are able to be joined, the weld is littered with defects such as cracks, cavities, and wormholes. The focus of this project was to use friction stir welding to create a defect-free joint between Al 2139 and Mg WE43. The stir tool used in this project, made of H13 tool steel, is of fixed design. The design included an 11 mm scrolled and concav… more
Date: December 2016
Creator: Reese, Gregory A
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Cyclic Polarization of AA 3102 in Corrosive Electrolytes Containing Sodium Chloride and Ammonium Sulfate

Description: Corrosion of all aluminum microchannel heat exchangers present a challenge in automotive and heating, ventilation, and air conditioning (HVAC) industries. Reproducibility of Salt Water Acetic Acid Test (SWAAT) has been questioned and a need to new corrosion tests with better reproducibility has risen. Cyclic polarization, that is an electrochemical test, was explored for its suitability for the assessment of AA 3102 tube material that is currently a popular aluminum alloy used in manufacturing… more
Date: December 2016
Creator: Dorreyatim, Mohammad
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Modeling of Fracture Toughness of Magnesium Alloy WE43 Before and After Friction Stir Processing

Description: Magnesium alloys are a popular research topic for structural applications because they have a lower density than conventional structural materials, including steel, titanium, and aluminum; however, the reliability and safety of their mechanical properties must be further proven. An important mechanical property for this purpose is fracture toughness, which is the measure of the material's resistance to crack propagation. In this study, a model of an experiment to investigate the fracture toughn… more
Date: December 2016
Creator: Lipscomb, Celena Andrea
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Development of a Natural Fiber Mat Plywood Composite

Description: Natural fibers like kenaf, hemp, flax and sisal fiber are becoming alternatives to conventional petroleum fibers for many applications. One such applications is the use of Non-woven bio-fiber mats in the automobile and construction industries. Non-woven hemp fiber mats were used to manufacture plywood in order to optimize the plywood structure. Hemp fiber mats possess strong mechanical properties that comparable to synthetic fibers which include tensile strength and tensile modulus. This study … more
Date: August 2017
Creator: Anthireddy, Prasanna Kumar
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Investigation of an Investment Casting Method Combined with Additive Manufacturing Methods for Manufacturing Lattice Structures

Description: Cellular metals exhibit combinations of mechanical, thermal and acoustic properties that provide opportunities for various implementations and applications; light weight aerospace and automobile structures, impact and noise absorption, heat dissipation, and heat exchange. Engineered cell topologies enable one to control mechanical, thermal, and acoustic properties of the gross cell structures. A possible way to manufacture complex 3D metallic cellular solids for mass production with a relativel… more
Date: August 2013
Creator: Kodira, Ganapathy D.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Use of Bio-Product/Phase Change Material Composite in the Building Envelope for Building Thermal Control and Energy Savings

Description: This research investigates the bio-products/phase change material (PCM) composites for the building envelope application. Bio-products, such as wood and herb, are porous medium, which can be applied in the building envelope for thermal insulation purpose. PCM is infiltrated into the bio-product (porous medium) to form a composite material. The PCM can absorb/release large amount of latent heat of fusion from/to the building environment during the melting/solidification process. Hence, the PCM-b… more
Date: August 2018
Creator: Boozula, Aravind Reddy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

Description: There is a wide range of applications for 3D printing technology with an additive manufacturing such as aerospace, automotive, marine and oil/gas, medical, consumer, electronics, building construction, and many others. There have been many pros and cons for 3D additive manufacturing. Even though 3D printing technology has many advantages: freedom to design and innovate without penalties, rapid iteration through design permutations, excellence mass customization, elimination of tolling, green ma… more
Date: December 2015
Creator: Mun, Jiwon
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Direct Strength Method for Web Crippling of Cold-formed Steel C and Z Sections Subjected to Interior One Flange Loading and End One Flange Loading

Description: The main objective of this research is to extend the “Direct strength method” for determining the web crippling strength of cold-formed steel C and Z sections subjected to End one flange loading and Interior one flange loading conditions. Direct strength method is applied for designing the columns and beams earlier. The existing specifications equation for calculating the web crippling strength of cold-formed steels designed by American Institute of Iron and Steel is very old method and it is b… more
Date: December 2015
Creator: Dara, Martin Luther
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Evaluation of the Influence of Non-Conventional Sources of Emissions on Ambient Air Pollutant Concentrations in North Texas

Description: Emissions of air pollutants from non-conventional sources have been on the rise in the North Texas area over the past decade. These include primary pollutants such as volatile organic compound (VOC) and oxides of nitrogen (NOx) which also act as precursors in the formation of ozone. Most of these have been attributed to a significant increase in oil and gas production activities since 2000 within the Barnett Shale region adjacent to the Dallas-Fort Worth metroplex region. In this study, air q… more
Date: August 2015
Creator: Lim, Guo Quan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Membrane-Based Energy Recovery Ventilator Coupled with Thermal Energy Storage Using Phase Change Material for Efficient Building Energy Savings

Description: This research work is focused on a conceptual combination of membrane-based energy recovery ventilator (ERV) and phase change material (PCM) to provide energy savings in building heating, ventilation & air-conditioning (HVAC) systems. An ERV can recover thermal energy and moisture between the outside fresh air (OFA) entering into the building and the exhaust air (EA) leaving from the building thus reducing the energy consumption of the HVAC system for cooling and heating the spaces inside the b… more
Date: December 2018
Creator: Mohiuddin, Mohammed Salman
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Comparative Study of Thermal Comfort Models Using Remote-Location Data for Local Sample Campus Building as a Case Study for Scalable Energy Modeling at Urban Level Using Virtual Information Fabric Infrastructure (VIFI)

Description: The goal of this dissertation is to demonstrate that data from a remotely located building can be utilized for energy modeling of a similar type of building and to demonstrate how to use this remote data without physically moving the data from one server to another using Virtual Information Fabric Infrastructure (VIFI). In order to achieve this goal, firstly an EnergyPlus model was created for Greek Life Center, a campus building located at University of North Texas campus at Denton in Texas, U… more
Date: December 2018
Creator: Talele, Suraj Harish
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Study of Metal Whiskers Growth and Mitigation Technique Using Additive Manufacturing

Description: For years, the alloy of choice for electroplating electronic components has been tin-lead (Sn-Pb) alloy. However, the legislation established in Europe on July 1, 2006, required significant lead (Pb) content reductions from electronic hardware due to its toxic nature. A popular alternative for coating electronic components is pure tin (Sn). However, pure tin has the tendency to spontaneously grow electrically conductive Sn whisker during storage. Sn whisker is usually a pure single crystal tin … more
Date: August 2015
Creator: Gullapalli, Vikranth
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Preliminary Analysis of an Innovative Rotary Displacer Stirling Engine

Description: Stirling engines are an external combustion heat engine that converts thermal energy into mechanical work that a closed cycle is run by cyclic compression and expansion of a work fluid (commonly air or Helium) in which, the working fluid interacts with a heat source and a heat sink and produces network. The engine is based on the Stirling cycle which is a subset of the Carnot cycle. The Stirling cycle has recently been receiving renewed interest due to some of its key inherent advantages. In p… more
Date: December 2015
Creator: Bagheri, Amirhossein
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Particle Image Velocimetry Sensitivity Analysis Using Automatic Differentiation

Description: A particle image velocimetry (PIV) computer software is analyzed in this work by applying automatic differentiation on it. We create two artificial images that contained particles that where moved with a known velocity field over time. These artificial images were created with parameters that we would have on real PIV experiments. Then we applied a PIV software to find the velocity output vectors. As we mentioned before, we applied automatic differentiation through all the algorithm to track th… more
Date: December 2016
Creator: Grullon Varela, Rodolfo Antonio
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Denim Fiberboard Fabricated from MUF and pMDI Hybrid Resin System

Description: In this study, a series of denim fiberboards are fabricated using two different resins, malamine urea formaldehyde (MUF) and polymeric methylene diphenyl diisocyanate (pMDI). Two experimental design factors (1) adhesive content and (2) MUF-pMDI weight ratio, were studied. All the denim fiberboard samples were fabricated following the same resin blending, cold-press and hot-press procedures. The physical and mechanical tests were conducted on the fiberboard following the procedures described in … more
Date: May 2019
Creator: Cui, Zhiying
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Increasing Effective Thermal Resistance of Building Envelope's Insulation Using Polyurethane Foam Incorporated with Phase Change Material

Description: Incorporating insulation material with phase change materials (PCMs) could help enhance the insulation capability for further building energy savings by reducing the HVAC loadings. During the phase change process between the solid and liquid states, heat is being absorbed or released by PCMs depending on the surrounding temperature. This research explores the benefits of a polyurethane (PU)-PCM composite insulation material through infiltrating paraffin wax as PCM into PU open cell foam. The ne… more
Date: May 2019
Creator: Houl, Yassine
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Quantification of Human Thermal Comfort for Residential Building's Energy Saving

Description: Providing conditioned and fully controlled room is the final goal for having a comfortable building. But on the other hand making smart controllers to provide the required cooling or heating load depending on occupants' real time feeling is necessary. This study has emphasized on finding a meaningful and steady state parameter in human body that can be interpreted as comfort criterion which can be expressed as the general occupants' sensation through their ambient temperature. There are lots of… more
Date: August 2016
Creator: Sharifani, Pooya
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Investigations of the Fresnel Lens Based Solar Concentrator System through a Unique Statistical-Algorithmic Approach

Description: This work investigates the Fresnel-lens-based solar concentrator-receiver system in a multi-perspective manner to design, test and fabricate this concentrator with high-efficiency photon and heat outputs and a minimized effect of chromatic aberrations. First, a MATLAB®-incorporated algorithm optimizes both the flat-spot and the curved lens designs via a statistical ray-tracing methodology of the incident light, considering all of its incidence parameters. The target is to maximize the solar ray… more
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Date: December 2019
Creator: Qandil, Hassan Darwish Hassan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Radial and Axial Designs for Magnetic Absorbent Collector in Water

Description: The use of collection systems for magnetic sorbents such as Magnetic Activated Carbon are discussed in order to gauge their efficacy in marine environments. Two collectors were built and tested, one which utilized a radial orientation of magnets and another with axially placed magnets. The two systems underwent a series of test with differing linear velocities and angular velocities. From the results, the axial system outperformed its radial counterpart, being most effective with a relatively h… more
Date: August 2020
Creator: Renzetti, Andrew John
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Design Optimization of Functionalized Silica-Polymer Nanocomposite through Finite Element and Molecular Dynamics Modeling

Description: This dissertation focuses on studying membrane air dehumidification for a membrane moisture exchanger in a membrane heat pump system. The study has two parts: an optimization of membrane moisture exchanger for air dehumidification in the macroscale, and diffusion of water vapor in polymer nanocomposites membrane for humid air dehumidification in the nanoscale. In the first part of the research, the mass transport of water vapor molecules through hydrophilic silica nanochannel chains in hydropho… more
Date: August 2020
Creator: Almahmoud, Omar H. M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Thermal Transport Modeling in Three-Dimensional Pillared-Graphene Structures for Efficient Heat Removal

Description: Pillared-graphene structure (PGS) is a novel three-dimensional structure consists of parallel graphene sheets that are separated by carbon nanotube (CNT) pillars that is proposed for efficient thermal management of electronics. For microscale simulations, finite element analyses were carried out by imposing a heat flux on several PGS configurations using a Gaussian pulse. The temperature gradient and distribution in the structures was evaluated to determine the optimum design for heat transfer.… more
Date: December 2020
Creator: Almahmoud, Khaled Hasan Musa
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

The Role of Interface in Crystal Growth, Energy Harvesting and Storage Applications

Description: A flexible nanofibrous PVDF-BaTiO3 composite material is prepared for impact sensing and biomechanical energy harvesting applications. Dielectric polyvinylidene fluoride (PVDF) and barium titanate (BaTiO3)-PVDF nanofibrous composites were made using the electrospinning process based on a design of experiments approach. The ultrasonication process was optimized using a 2k factorial DoE approach to disperse BaTiO3 particles in PVDF solution in DMF. Scanning electron microscopy was used to charact… more
Date: December 2020
Creator: Ramesh, Dinesh
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Study of Mechanical Performance of Stent Implants Using Theoretical and Numerical Approach

Description: The coronary heart disease kills more than 350,000 persons/year and it costs $108.9 billion for the United States each year, in spite of significant advancements in clinical care and education for public, cardiovascular diseases (CVD) are leading cause of death and disability to the nation. A cardiovascular disease involves mainly heart or blood vessels (arteries, veins and capillaries) or both, and then mainly occurs in selected regions and affects heart, brain, kidney and peripheral arteries.… more
Date: August 2015
Creator: Yang, Hua, (Mechanical engineer)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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