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open access

Adhesion and Surface Energy Profiles of Large-area Atomic Layers of Two-dimensional MoS2 on Rigid Substrates by Facile Methods

Description: Two-dimensional (2D) transition metal dichalcogenides (TMDs) show great potential for the future electronics, optoelectronics and energy applications. But, the studies unveiling their interactions with the host substrates are sparse and limits their practical use for real device applications. We report the facile nano-scratch method to determine the adhesion energy of the wafer scale MoS2 atomic layers attached to the SiO2/Si and sapphire substrates. The practical adhesion energy of monolayer M… more
Date: May 2016
Creator: Wu, Min
Item Type: Refine your search to only Thesis or Dissertation
open access

Analysis of Sources Affecting Ambient Particulate Matter in Brownsville, Texas

Description: Texas is the second largest state in U.S.A. based on geographical area, population and the economy. It is home to several large coastal urban areas with major industries and infrastructure supporting the fossil-fuel based energy sector. Most of the major cities on the state have been impacted by significant air pollution events over the past decade. Studies conducted in the southern coastal region of TX have identified long range transport as a major contributor of particulate matter (PM) pol… more
Date: May 2012
Creator: Diaz Poueriet, Pablo
Item Type: Refine your search to only Thesis or Dissertation
open access

Application of Cyclic Polarization of Aluminum 3003 Used in All-Aluminum Microchannel Heat Exchangers

Description: All-aluminum microchannel heat exchangers are designed to significantly reduce refrigerant charge requirements, weight, reduced brazed joints, and decreased potential for leakage by increasing reliability. Al 3003 alloy is corrosion resistant and can be formed, welded, and brazed but the issue with all-aluminum heat exchangers is localized corrosion (pitting) in corrosive environments. Currently, there is no universally accepted corrosion test that all coil manufacturers use to characterize the… more
Date: May 2015
Creator: Barnes, Javier
Item Type: Refine your search to only Thesis or Dissertation
open access

Application of High Entropy Alloys in Stent Implants

Description: High entropy alloys (HEAs) are alloys with five or more principal elements. Due to these distinct concept of alloying, the HEA exhibits unique and superior properties. The outstanding properties of HEA includes higher strength/hardness, superior wear resistance, high temperature stability, higher fatigue life, good corrosion and oxidation resistance. Such characteristics of HEA has been significant interest leading to researches on these emerging field. Even though many works are done to unders… more
Date: May 2017
Creator: Alagarsamy, Karthik
Item Type: Refine your search to only Thesis or Dissertation
open access

Bioinspired & biocompatible coatings of poly(butylene adipate-co-terephthalate) and layer double hydroxide composites for corrosion resistance

Description: Hierarchical arrangement of biological composites such as nacre and bone containing high filler (ceramic) content results in high strength and toughness of the natural material. In this study we mimic the design of layered bone microstructure and fabricate an optimal multifunctional bio-nanocomposite having strength, toughness and corrosion resistance. Poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer was used as a substrate material with the reinforcement of LDH (Layered… more
Date: May 2016
Creator: Rizvi, Hussain R.
Item Type: Refine your search to only Thesis or Dissertation
open access

Biomass-Derived Activated Carbon Through Self-Activation Process

Description: Self-activation is a process that takes advantage of the gases emitted from the pyrolysis process of biomass to activate the converted carbon. The pyrolytic gases from the biomass contain CO2 and H2O, which can be used as activating agents. As two common methods, both of physical activation using CO2 and chemical activation using ZnCl2 introduce additional gas (CO2) or chemical (ZnCl2), in which the CO2 emission from the activation process or the zinc compound removal by acid from the follow-up… more
Date: May 2016
Creator: Xia, Changlei
Item Type: Refine your search to only Thesis or Dissertation
open access

Deleterious Synergistic Effects of Concurrent Magnetic Field and Superparamagnetic (Fe3O4) Nanoparticle Exposures on CHO-K1 Cell Line

Description: While many investigations have been performed to establish a better understanding of the effects that magnetic fields and nanoparticles have on cells, the fundamental mechanisms behind the interactions are still yet unknown, and investigations on concurrent exposure are quite limited in scope. This study was therefore established to investigate the biological impact of concurrent exposure to magnetic nanoparticles and extremely-low frequency magnetic fields using an in-vitro CHO-K1 cell line mo… more
Date: May 2015
Creator: Coker, Zachary
Item Type: Refine your search to only Thesis or Dissertation
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
open access

Design of a Lower Extremity Exoskeleton to Increase Knee ROM during Valgus Bracing for Osteoarthritic Gait

Description: Knee osteoarthritis (KOA) is the primary cause of chronic immobility in populations over the age of 65. It is a joint degenerative disease in which the articular cartilage in the knee joint wears down over time, leading to symptoms of pain, instability, joint stiffness, and misalignment of the lower extremities. Without intervention, these symptoms gradually worsen over time, decreasing the overall knee range of motion (ROM) and ability to walk. Current clinical interventions include offloading… more
Date: May 2017
Creator: Cao, Jennifer M.
Item Type: Refine your search to only Thesis or Dissertation
open access

Effectiveness of Fillers for Corrosion Protection of AISI-SAE 1018 Steel in Sea Salt Solution

Description: Corrosion represents the single most frequent cause for product replacement or loss of product functionality with a 5% coat to the industrial revenue generation of any country in this dissertation the efficacy of using filled coatings as a protection coating are investigated. Fillers disrupt the polymer-substrate coating interfacial area and lead to poor adhesion. Conflicting benefits of increasing surface hardness and corrosion with long term durability through loss of adhesion to the subst… more
Date: May 2017
Creator: Al-Shenawa, Amaal
Item Type: Refine your search to only Thesis or Dissertation
open access

Estimation of Air Emissions During Production Phase from Active Oil and Gas Wells in the Barnett Shale Basin: 2010-2013

Description: The Barnett shale basin, the largest onshore gas field in the state of Texas, mainly produces natural gas. The basin’s oil and gas productions have dramatically increased over the past two decades with the enhancement via shale fracturing (fracking) technology. However, recent studies suggest that air emissions from shale fracking have significantly contributed to the growing air pollution problem in North Texas. In this study, air emissions from the Barnett shale basin during the production ph… more
Date: May 2015
Creator: Dohde, Farhan A.
Item Type: Refine your search to only Thesis or Dissertation
open access

Estimation of Aircraft Emissions for the Corpus Christi International Airport, Corpus Christi, Texas

Description: Commercial aviation is a vital part of the United States economy. It generates over $1 trillion annually, which is more than 5% of the U.S. GDP, and produces approximately 10 million jobs. Every year there is an increase in commercial air traffic. This is attributed to expanding trade between states and other countries, which requires larger amounts of cargo aircraft in operation, and also catering to the growing number of middle and upper class passengers who travel for business and pleasure p… more
Date: May 2013
Creator: Thomas, Gregson Johann
Item Type: Refine your search to only Thesis or Dissertation
open access

An Evaluation of Long-Term Air Quality Trends in North Texas using Statistical and Machine Learning Techniques

Description: While ozone design values have decreased since 2000, the values measured in Denton Airport South (DEN), an exurban region in the northwest tip of the Dallas-Fort Worth (DFW) metroplex, remains above those measured in Dallas Hinton (DAL) and Fort Worth Northwest (FWNW), two extremely urbanized regions; in addition, all three sites remained in nonattainment of National Ambient Air Quality Standards (NAAQS) ozone despite reductions in measured NOx and CO concentrations. The region's inability to a… more
Date: May 2020
Creator: Lim, Guo Quan
Item Type: Refine your search to only Thesis or Dissertation
open access

Experimental Study on Fluidization of Biomass, Inert Particles, and Biomass/Sand Mixtures

Description: Fluidization of biomass particles is an important process in the gasification, pyrolysis and combustion in order to extract energy from biomass. Studies on the fluidization of biomass particles (corn cob and walnut shell), inert particles (sand, glass bead, and alumina), which are added to facilitate fluidization of biomass, and biomass/sand mixture were performed. Experiments were carried out in a 14.5 cm internal diameter cold flow fluidization bed to determine minimum fluidization velocities… more
Date: May 2011
Creator: Paudel, Basu
Item Type: Refine your search to only Thesis or Dissertation
open access

Feasibility of a New Technique to Determine Dynamic Tensile Behavior of Brittle Materials

Description: Dynamic tensile characterization of geo-materials is critical to the modeling and design of protective structures that are often made of concrete. One of the most commonly used techniques currently associated with this type of testing is performed with a Kolsky bar and is known as the spall technique. The validity of the data from the spall technique is highly debated because the necessary boundary conditions for the experiment are not satisfied. By using a technique called pulse shaping, a new… more
Date: May 2016
Creator: Dean, Andrew W.
Item Type: Refine your search to only Thesis or Dissertation
open access

Field Validation of Zero Energy Lab Water-to-Water Ground Coupled Heat Pump Model

Description: Heat pumps are a vital part of each building for their role in keeping the space conditioned for the occupant. This study focuses on developing a model for the ground-source heat pump at the Zero Energy lab at the University of North Texas, and finding the minimum data required for generating the model. The literature includes many models with different approaches to determine the performance of the heat pump. Each method has its pros and cons. In this research the equation-fit method was used … more
Date: May 2016
Creator: Abdulameer, Saif
Item Type: Refine your search to only Thesis or Dissertation
open access

High-Density Polyethylene/Peanut Shell Biocomposites

Description: A recent trend in the development of renewable and biodegradable materials has led to the development of composites from renewal sources such as natural fibers. This agricultural activity generates a large amount of waste in the form of peanut shells. The motivation for this research is based on the utilization of peanut shells as a viable source for the manufacture of biocomposites. High-density polyethylene (HDPE) is a plastic largely used in the industry due to its durability, high strength … more
Date: May 2014
Creator: Londoño Ceballos, Mauricio
Item Type: Refine your search to only Thesis or Dissertation
open access

Highly Stretchable Miniature Strain Sensor for Large Dynamic Strain Measurement

Description: This thesis aims to develop a new type of highly stretchable strain sensor to measure large deformation of a specimen subjected to dynamic loading. The sensor was based on the piezo-resistive response of carbon nanotube(CNT)/polydimethysiloxane (PDMS) composites thin films, some nickel particles were added into the sensor composite to improve the sensor performance. The piezo-resistive response of CNT composite gives high frequency response in strain measurement, while the ultra-soft PDMS matri… more
Date: May 2016
Creator: Yao, Shulong
Item Type: Refine your search to only Thesis or Dissertation
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
open access

Investigation of a Novel Vapor Chamber for Efficient Heat Spreading and Removal for Power Electronics in Electric Vehicles

Description: This work investigated a novel vapor chamber for efficient heat spreading and heat removal. A vapor chamber acting as a heat spreader enables for more uniform temperature distribution along the surface of the device being cooled. First, a vapor chamber was studied and compared with the traditional copper heat spreader. The thickness of vapor chamber was kept 1.35 mm which was considered to be ultra-thin vapor chamber. Then, a new geometrical model having graphite foam in vapor space was propose… more
Date: May 2017
Creator: Patel, Anand Kishorbhai
Item Type: Refine your search to only Thesis or Dissertation
open access

Investigation of the Effect of Particle Size and Particle Loading on Thermal Conductivity and Dielectric Strength of Thermoset Polymers

Description: Semiconductor die attach materials for high voltage, high reliability analog devices require high thermal conductivity and retention of dielectric strength. A comparative study of effective thermal conductivity and dielectric strength of selected thermoset/ceramic composites was conducted to determine the effect of ceramic particle size and ceramic particle loading on thermoset polymers. The polymer chosen for this study is bismaleimide, a common aerospace material chosen for its strength and t… more
Date: May 2016
Creator: Warner, Nathaniel A.
Item Type: Refine your search to only Thesis or Dissertation
open access

Investigation on the Effects of Indoor Temperature Modulations on Building Energy Usage and Human Thermal Comfort

Description: Energy efficiency in the operation of buildings is becoming increasingly important with a growing emphasis on sustainability and reducing environmental impacts of irresponsible energy usage. Improvements have been made both on the technology side of energy efficiency and on the human behavior side. However, when changing human behavior, it is critical to find energy conservation measures that will maintain comfort for occupants. This paper analyzes how this can be done by implementing a modulat… more
Date: May 2017
Creator: Traylor, Caleb
Item Type: Refine your search to only Thesis or Dissertation
open access

Loading Mode Dependent Effective Properties of Octet-truss Lattice Structures Using 3D-Printing

Description: Cellular materials, often called lattice materials, are increasingly receiving attention for their ultralight structures with high specific strength, excellent impact absorption, acoustic insulation, heat dissipation media and compact heat exchangers. In alignment with emerging additive manufacturing (AM) technology, realization of the structural applications of the lattice materials appears to be becoming faster. Considering the direction dependent material properties of the products with AM, … more
Date: May 2015
Creator: Challapalli, Adithya
Item Type: Refine your search to only Thesis or Dissertation
open access

Micro-Pipette Thermal Sensor: A Unique Technique for Thermal Characterization of Microfluids, Microsphere, and Biological Cell

Description: In this research work, an innovative method for measurement of thermal conductivity of a small volume of liquids, microsphere, and the single cancer cell is demonstrated using a micro-pipette thermal sensor (MPTS). The method is based on laser point heating thermometry (LPHT) and transient heat transfer. When a single pulse of a laser beam heats the sensor tip which is in contact with the surrounding liquids or microsphere/cells, the temperature change in the sensor is reliant on the thermal pr… more
Date: May 2020
Creator: Shrestha, Ramesh
Item Type: Refine your search to only Thesis or Dissertation
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