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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
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
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
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
Partner: UNT Libraries

Thermal Transport Properties Enhancement of Phase Change Material by Using Boron Nitride Nanomaterials for Efficient Thermal Management

Description: In this research thermal properties enhancement of phase change material (PCM) using boron nitride nanomaterials such as nanoparticles and nanotubes is studied through experimental measurements, finite element method (FEM) through COMSOL 5.3 package and molecular dynamics simulations via equilibrium molecular dynamics simulation (EMD) with the Materials and Process Simulations (MAPS 4.3). This study includes two sections: thermal properties enhancement of inorganic salt hydrate (CaCl2∙6H2O) as … more
Date: December 2020
Creator: Barhemmati Rajab, Nastaran
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.
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
Partner: UNT Libraries

Passive Control of Fiber Orientation in Direct Ink Writing 3D Printing

Description: Several active methods, which requires external control systems and moving parts, have been developed to control the fiber orientation during 3D printing. Active mechanisms like rotating nozzle, impeller, and magnetic field have been integrated to realize complex internal fiber structures. In this study, instead of using active methods, I investigate a passive method for controlling the fiber orientation without any moving parts or additional mechatronics added in the printing process. Composit… more
Date: August 2020
Creator: Khatri, Nava Raj
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
Partner: UNT Libraries

Refrigeration Insulation Using Phase Change Material Incorporated Polyurethane Foam for Energy Savings

Description: Incorporating insulation material with phase change materials (PCMs) could help enhance the insulation capability for a refrigerator system. The phase change material can absorb or release large amount of latent heat of fusion depending on surrounding temperatures for efficient thermal management. This research focuses on how incorporating PCM to the conventional PU foam insulation affects the inside temperatures of the refrigerator system and in-turn helps in conserving energy by reducing the … more
Date: August 2020
Creator: Shaik, Sania
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
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
Partner: UNT Libraries

Characterization, Analysis, and Optimization of Rotary Displacer Stirling Engines

Description: This work focuses on an innovative Rotary Displacer SE (RDSE) configuration for Stirling engines (SEs). RDSE features rotary displacers instead of reciprocating displacers (found in conventional SE configurations), as well as combined compression and expansion spaces. Guided by the research question "can RDSE as a novel configuration achieve a higher efficiency compared to conventional SE configurations at comparable operating conditions?", the goal of this study is to characterize, analyze, an… more
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Date: December 2019
Creator: Bagheri, Amirhossein
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
Access: Restricted to UNT Community Members. Login required if off-campus.
Date: December 2019
Creator: Qandil, Hassan Darwish Hassan
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
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
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
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
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
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
Partner: UNT Libraries
open access

Microcantilever Based Viscosity Measurement as it Applies to Oscillation Amplitude Response

Description: The goal of this research is to measure viscosity via the analysis of amplitude response of a piezo driven vibrating cantilevers partially immersed in a viscous medium. As a driving frequency is applied to a piezoceramic material, the external forces acting on the system will affect its maximum amplitude. This thesis applies this principle through experimental and analytical analyses of the proportional relationship between viscosity and the amplitude response of the first natural frequency mod… more
Date: August 2018
Creator: Siegel, Sanford H.
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
Partner: UNT Libraries
open access

Analysis of Heat Transfer Enhancement in Channel Flow through Flow-Induced Vibration

Description: In this research, an elastic cylinder that utilized vortex-induced vibration (VIV) was applied to improve convective heat transfer rates by disrupting the thermal boundary layer. Rigid and elastic cylinders were placed across a fluid channel. Vortex shedding around the cylinder led to the periodic vibration of the cylinder. As a result, the flow-structure interaction (FSI) increased the disruption of the thermal boundary layer, and therefore, improved the mixing process at the boundary. This … more
Date: December 2017
Creator: Kota, Siva Kumar k
Partner: UNT Libraries
open access

Estimating Thermal Conductivity and Volumetric Specific Heat of a Functionally Graded Material using Photothermal Radiometry

Description: Functionally graded materials (FGMs) are inhomogeneous materials in which the material properties vary with respect to space. Research has been done by scientific community in developing techniques like photothermal radiometry (PTR) to measure the thermal conductivity and volumetric heat capacity of FGMs. One of the problems involved in the technique is to solve the inverse problem, i.e., estimating the thermal properties after the frequency scan has been obtained. The present work involves fin… more
Date: December 2017
Creator: Koppanooru, Sampat Kumar Reddy
Partner: UNT Libraries
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