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open access

Design of Bioinspired Conductive Smart Textile

Description: Electrically conductive fabrics are one of the major components of smart textile that attracts a lot of attention by the energy, medical, sports and military industry. The principal contributors to the conductivity of the smart textiles are the intrinsic properties of the fiber, functionalization by the addition of conductive particles and the architecture of fibers. In this study, intrinsic properties of non-woven carbon fabric derived from a novel linear lignin, poly-(caffeyl alcohol) (PCFA) … more
Date: August 2017
Creator: Rizvi, Syed Hussain Raza
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Lignocellulose-Based Nanobiocomposites for Water Purification

Description: The research focuses on the synthesis and application of multifunctional lignocellulosic biomass bioadsorbent and nanobiocomposites for water purification. A bioadsorbent was prepared from kenaf fiber by self-activation without the use of any toxic chemicals in an innovative method. Silver nanoparticles were synthesized by the green route and then impregnated on the surface of kenaf-based activated carbon (KAC), and hemp fibers by heating and photoirradiation. The formation of hemp-based and ke… more
Date: August 2021
Creator: Mandal, Sujata
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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
Partner: UNT Libraries
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
Partner: UNT Libraries
open access

A study of the impact of unconventional sources within a large urban area: evidence from spatio-temporal assessment of volatile organic compounds.

Description: Conventional sources of emissions have been a prime target for policymakers in designing pollution control strategies. However, the evolution of shale gas activities is a growing concern over the impact of unconventional sources on urban and regional air quality. Owing to the development of Barnett Shale production, the fast-growing Dallas-Fort Worth (DFW) metroplex has encountered both types of these emissions. Oil and gas activities result in emissions of ozone precursors, notably volatile or… more
Date: May 2016
Creator: Matin, Maleeha
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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
Partner: UNT Libraries
open access

Optimization of Superhydrophobic Surfaces to Maintain Continuous Dropwise Condensation

Description: In the past decade, the condensation on superhydrophobic surfaces has been investigated abundantly to achieve dropwise condensation. There is not a specific approach in choosing the size of the roughness of the superhydrophobic surfaces and it was mostly selected arbitrarily to investigate the behavior of condensates on these surfaces. In this research, we are optimizing the size of the roughness of the superhydrophobic surface in order to achieve dropwise condensation. By minimizing the resist… more
Date: May 2014
Creator: Vandadi, Aref
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

Ozone Pollution of Shale Gas Activities in North Texas

Description: The effect of shale gas activities on ground-level ozone pollution in the Dallas-Fort Worth area is studied in detail here. Ozone is a highly reactive species with harmful effects on human and environment. Shale gas development, or fracking, involves activities such as hydraulic fracturing, drilling, fluid mixing, and trucks idling that are sources of nitrogen oxides (NOX) and volatile organic compounds (VOC), two of the most important precursors of ozone. In this study two independent approach… more
Date: May 2016
Creator: Ahmadi, Mahdi
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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
Partner: UNT Libraries
open access

Piezoelectric-Based Gas Sensors for Harsh Environment Gas Component Monitoring

Description: In this study, gas sensing systems that are based on piezoelectric smart material and structures are proposed, designed, developed, and tested, which are mainly aimed to address the temperature dependent CO2 gas sensing in a real environment. The state-of-the-art of gas sensing technologies are firstly reviewed and discussed for their pros and cons. The adsorption mechanisms including physisorption and chemisorption are subsequently investigated to characterize and provide solutions to various … more
Date: August 2019
Creator: Zhang, Chen
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

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
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

Enhanced Coarse-Graining for Multiscale Modeling of Elastomers

Description: One of the major goal of the researchers is to reduce energy loss including nanoscale to the structural level. For instance, around 65% of fuel energy is lost during the propulsion of the automobiles, where 11% of the loss happens at tires due to rolling friction. Out of that tire loss, 90 to 95% loss happens due to hysteresis of tire materials. This dissertation focuses on multiscale modeling techniques in order to facilitate the discovery new rubber materials. Enhanced coarse-grained models o… more
Date: December 2016
Creator: Uddin, Md Salah
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Carbon Capture Utilization for Bio-Based Building Insulation Foams

Description: Ecological, health and environmental concerns are driving the need for bio-resourced foams for the building industry and for other applications. This is because insulation is one of the most important aspects of the building envelope. Global building insulation is expected to reach USD 27.74 billion in 2022. Conventional insulation materials currently used in buildings are made from nonrenewable products (petroleum, fiber glass). However, they yield increasing unrecyclable eco-unfriendly waste … more
Date: August 2021
Creator: Oluwabunmi, Kayode Emmanuel
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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
Partner: UNT Libraries
open access

Modeling of Hexagonal Boron Nitride Filled Bismalemide Polymer Composites for Thermal and Electrical Properties for Electronic Packaging

Description: Due to the multi-tasking and miniaturization of electronic devices, faster heat transfer is required from the device to avoid the thermal failure. Die-attached polymer adhesives are used to bond the chips in electronic packaging. These adhesives have to hold strong mechanical, thermal, dielectric, and moisture resistant properties. As polymers are insulators, heat conductive particles are inserted in it to enhance the thermal flow with an attention that there would be no electrical conductivity… more
Date: December 2016
Creator: Uddin, Md Salah
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Heat Transfer Analysis of a Small Thermochemical Reactor for Hydrogen Production from Ammonia

Description: Several types of research are ongoing throughout the world, to discover economical and reliable techniques to create hydrogen, and propagate the vision of a hydrogen economy. This research examines a COMSOL Multiphysics 5.4 heat transfer model for a hydrogen production system consisting of a retort with two different heat sources, namely a heat tape and an infrared (IR) lamp. The main objective was to compare the two heat sources and find out which one offers a better technique for producing hy… more
Date: August 2020
Creator: Owusu-Ansah, Nana
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 Influence of Surface Roughness and Its Geometry on Dynamic Behavior of Water Droplets

Description: In this study the author reports the effects of surface roughness on dynamic behavior of water droplets on different types of rough structures. First, the influence of roughness geometry on the Wenzel/ Cassie-Baxter transition of water droplets on one-tier (solid substrates with Si micropillars) surfaces is studied (Chapter 3). In order to address distinct wetting behaviors of the advancing and receding motions, the author investigates the Wenzel/ Cassie-Baxter transition of water droplets on o… more
Date: December 2014
Creator: Sadeghpour, Nima.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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
Partner: UNT Libraries
open access

Heat Transfer in Low Dimensional Materials Characterized by Micro/Nanoscae Thermometry

Description: In this study, the thermal properties of low dimensional materials such as graphene and boron nitride nanotube were investigated. As one of important heat transfer characteristics, interfacial thermal resistance (ITR) between graphene and Cu film was estimated by both experiment and simulation. In order to characterize ITR, the micropipette sensing technique was utilized to measure the temperature profile of suspended and supported graphene on Cu substrate that is subjected to continuous wave l… more
Date: August 2018
Creator: Jeong, Jae Young
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Electrodepostion of Iron Oxide on Steel Fiber for Improved Pullout Strength in Concrete

Description: Fiber-reinforced concrete (FRC) is nowadays extensively used in civil engineering throughout the world due to the composites of FRC can improve the toughness, flexural strength, tensile strength, and impact strength as well as the failure mode of the concrete. It is an easy crazed material compared to others materials in civil engineering. Concrete, like glass, is brittle, and hence has a low tensile strength and shear capacity. At present, there are different materials that have been employed … more
Date: August 2014
Creator: Liu, Chuangwei
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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