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Heat Transfer Analysis of Bio-Printed Tissue Mimicking Material Mixed with Silver Nanoparticles

Description: Novel tissue mimicking materials have been developed for cancer treatment research. In the present research work, the tissue mimicking material is printed using 3D bioprinting technology. The nanoparticles are homogeneously mixed with tissue mimicking materials to enhance the heating capacity. The thermal conductivity of tissue mimicking materials is measured using a micropipette thermal sensor (MTS). Further, the optimal value is identified based on optimization technique and incorporated into… more
Date: August 2022
Creator: Chandrasegaran, Jedeshkeran
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Development of an Enclosed Evaporation Chamber Utilizing a Fresnel Lens Solar Concentrator

Description: This thesis project investigates the configuration of an enclosed evaporation chamber with the intention of converting seawater into potable freshwater. The evaporation chamber's sole heat source is provided by a Fresnel lens, located above the chamber, which concentrates sunlight onto a 3-inch diameter focal plate built into the core of the chamber. The design of the evaporation chamber is modeled after a solar still and is coupled with a heat exchanger to boost efficiency of the system. The c… more
Date: August 2022
Creator: Planz, Bridger T
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of Interfacial Property with Imperfection: A Machine Learning Approach

Description: Interfacial mechanical properties of adhesive joints are very crucial in board applications, including composites, multilayer structures, and biomedical devices. Establishing traction-separation (T-S) relations for interfacial adhesion can evaluate mechanical and structural reliability, robustness, and failure criteria. Due to the short range of interfacial adhesion such as micro to nanoscale, accurate measurements of T-S relations remain challenging. The advent of machine learning (ML) became … more
Date: July 2023
Creator: Ferdousi, Sanjida
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Structural Design and Its Impact on Thermal Efficiency and Corrosion of All-Aluminum Microchannel Heat Exchangers

Description: In this study, high-fidelity conjugate heat transfer simulations are used to model a micro-channel heat exchanger (MCHE) in a crossflow to study its thermal-hydraulic performance. This study considers three different microchannels (internal flow) geometries (circular, triangular, and square) with louver-shaped fins. The local flow field showed a strong coupling between the microchannel flow, solid domain, and crossflow. The flow separation and wake regions formed near MCHE resulted in a large v… more
Date: July 2023
Creator: Ahmed, Hossain
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

3D Printed Self-Activated Carbon Electrodes for Supercapacitor Applications

Description: This study investigated a new approach to achieving high energy density supercapacitors (SCs) by using high surface area self-activated carbon from waste coffee grounds (WCGs) and modifying 3D printed electrodes' porous structure by varying infill density. The derived activated carbons' surface area, pore size, and pore volume were controlled by thermally treating the WCGs at different temperatures (1000˚C, 1100˚C, and 1200˚C) and post-treating with HCL to remove water-soluble ashes and contami… more
Date: July 2023
Creator: Disi, Onome Aghogho
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Suppression of Higher Acoustic Harmonics by Application of Solid-Solid Periodic Layered Structure in Nonlinear Ultrasonics Nondestructive Evaluation Field

Description: Nondestructive testing (NDT) using ultrasound band 1-5 MHz, has been widely used for the early-stage detection of structural failure; however, it fails to detectf material degradation, fatigue, and microcracks. NDT with nonlinear ultrasound (NLU) can detect a microscopic discontinuity or imperfection that may be a source of the second harmonic in the reflected signal. In this research, we focus on creating a metamaterial band filter that filters out nonlinearities induced by the instrument itse… more
Date: May 2023
Creator: Kang, Jinho
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Rapid, Approximate Multi-Axis Vibration Testing

Description: Sequential single-axis vibration testing strategies often produce over-testing when qualifying system hardware. Multi-axis excitation techniques can simulate realistic service environments, but the hardware and testing strategies needed to do so tend to be costly and complex. Test engineers instead must execute sequential tests on single-axis shaker tables to excite each degree of freedom, which the previous two decades of vibration testing literature have shown to cause extensive over-testing … more
Date: May 2023
Creator: Cramer, Ethan Savoy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Thermally Tunable Acoustic Beam Splitter Based on Poly(vinyl alcohol) Poly(N-isopropylacrylamide) Hydrogel

Description: Article demonstrating a thermally tunable acoustic beam splitter using a poly(vinyl alcohol) poly(N-isopropylacrylamide) hydrogel (PVA-pNIPAM). The nature of PVA-pNIPAM hydrogel offers exceptional temperature-dependent physical properties due to its phase transition around its lower critical solution temperature. The acoustic impedance of the hydrogel can be tuned below, above, or matched to that of water by changing the environmental temperature. An acoustic wave propagating in water can be sp… more
Date: September 13, 2021
Creator: Jin, Yuqi; Zhou, Mi; Choi, Tae-Youl & Neogi, Arup
Item Type: Refine your search to only Article
Partner: University of North Texas
open access

Study of the Corrosion Resistance of 316L Stainless Steel Made by Directed Energy Deposition for Applications at an Elevated Temperature

Description: The corrosion resistance under elevated temperature of additively manufactured 316L stainless steel made by directed energy deposition was studied. Test samples were prepared in a hybrid additive manufacturing machine using standard deposition parameters recommended by the manufacturer. Control samples were cut from wrought material to compare the results. The test was performed under a corrosive atmosphere with a solution of water with 3.5 % in weight of salt (NaCl). The total duration of the … more
Date: December 2021
Creator: Canales Cantu, Alberto Alejandro
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Tuning Effect on Thermal Radiative Emission of Thermo-Mechano-Optical Gratings and Multilayers

Description: The recipes of optical radiative properties manipulation are their materials chemistry, nano/microscale geometry, and transport properties of quasiparticle carriers such as photons, phonons, and electrons. The important technical element in optical properties is the dielectric function of materials, which is different for metals, dielectrics, 2D materials, and phase transition materials. Graphene has a unique electrical conductivity profile which have metallic nature depending on the frequency,… more
Date: December 2022
Creator: Araki, Ken
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Experimental Investigation on Efficiency of Fresnel Lenses with Different Manufacturing Methods

Description: Non-imaging Fresnel lenses have been playing an important role in improving the efficiency of the solar energy systems. Many researchers and scientists have devoted their research to optimize the design of the Fresnel lenses. Before it can contribute to energy efficiency increase, a Fresnel lens with optimized design will first need to be fabricated with the most cost-effective method as well as the best quality fabrication as possible. If targeted in a commercial market, feasibility of mass pr… more
Date: December 2020
Creator: Sexton, Ai Jiang
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

A Novel Thermal Regenerative Electrochemical System for Energy Recovery from Waste Heat

Description: Waste-heat-to-power (WHP) recovers electrical power from exhaust heat emitted by industrial and commercial facilities. Waste heat is available in enormous quantities. The U.S. Department of Energy estimates 5-13 quadrillion BTUs/yr with a technical potential of 14.6 GW are available and could be utilized to generate power by converting the heat into electricity. The research proposed here will define a system that can economically recover energy from waste heat through a thermal regenerative … more
Date: May 2021
Creator: Gray, David B
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Multi-Fidelity Study of Aerodynamics and Aeroacoustics Characteristics of a Quadrotor Biplane Tailsitter

Description: Recent advances in manufacturing and growing concerns on the sustainability of aviation environment have led to a remarkable interest in electrical unmanned aerial systems (UASs) in the past decade. Among various UAS types, the newly designed quadrotor biplane tailsitter class is capable of delivering a wide range of civilian and military tasks, relying on its Vertical Take-Off and Landing (VTOL) capability as well as great maneuverability. Nevertheless, as such UASs employ rotors to generate t… more
Date: May 2022
Creator: Heydari, Morteza
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Gradient-Index Metamaterial Infrared Detector for Enhanced Photo-Response and Image Quality

Description: An enhanced thermal imaging concept made possible through the development of a gradient-indexed metamaterial infrared detector that offers broadband transmission and reflection in THz waves. This thesis proposes a proof of feasibility for a metamaterial infrared detector containing an anti-reflective coating with various geometrically varying periodic metasurfaces, a gradient-indexed dielectric multilayer for near-perfect longpass filtering, and a gradient index of refraction (GRIN) metalens fo… more
Date: May 2022
Creator: Adams, Kelsa Derek
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Investigation of Structure-Property Effects on Nanoindentation and Small-Scale Mechanical Testing of Irradiated Additively Manufactured Stainless Steels

Description: Additively manufactured (AM) 316L and 17-4PH stainless steel parts, concretely made by laser powder bed fusion (L-PBF), are characterized and micro-mechanical properties of those steels are analyzed. This study also explored and extended to proton irradiation and small-scale mechanical testing of those materials, to investigate how irradiation affects microstructural evolution and thus mechanical properties at the surface level, which could be detrimental in the long term in nuclear application… more
Date: August 2022
Creator: Uddin, Mohammad Jashim
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Development of an Interpolation-Free Sharp Interface Immersed Boundary Method for General CFD Simulations

Description: Immersed boundary (IB) methods are attractive due to their ability to simulate flow over complex geometries on a simple Cartesian mesh. Unlike conformal grid formulation, the mesh does not need to conform to the shape and orientation of the boundary. This eliminates the need for complex mesh and/or re-meshing in simulations with moving/morphing boundaries, which can be cumbersome and computationally expensive. However, the imposition of boundary conditions in IB methods is not straightforward … more
Date: August 2022
Creator: Kamau, Kingora
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Artificial Neural Network Based Thermal Conductivity Prediction of Propylene Glycol Solutions with Real Time Heat Propagation Approach

Description: Machine learning is fast growing field as it can be applied to solve a large amount of problems. One large subsection of machine learning are artificial neural networks (ANN), these work on pattern recognition and can be trained with data sets of known solutions. The objective of this thesis is to discuss the creation of an ANN capable of classifying differences in propylene glycol concentrations, up to 10%. Utilizing a micro pipette thermal sensor (MTS) it is possible to measure the heat propa… more
Date: August 2022
Creator: Jarrett, Andrew Caleb
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Microgravity Vortex Phase Separator for Liquid Amine CO2 Removal System

Description: The present study investigates vortex phase separator (VPS) technology as a new approach for a liquid amine CO2 removal system. Experimental results obtained using a 99.99% pure CO2 stream and liquid amine with varying concentrations demonstrate the VPS' ability to decrease CO2 volume at its gas outlet. Operating parameters such as CO2 flow rate, relative humidity (RH), and temperature were systematically varied during experimental procedure, as well as working fluid temperature, volume, and fl… more
Date: August 2022
Creator: Sarvadi, Alexander Armstrong
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Optimization of Silica Nanocomposite Membranes for Air Dehumidification

Description: This thesis is focused on understanding the correct method to simulate atomistic models to calculate coefficient of diffusion of water through the membrane. It also aims to fix the method previously used in molecular modelling in which the simulation results did not match the experimental results. These membranes will be used in air dehumidification systems. The four types of membranes namely, polyurethane, polyurethane with silica nano particles, polyurethane with silica nano particles and ami… more
Date: May 2022
Creator: Appaji, Tejas
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Structural Analysis and Finite Element Modeling of Aluminum Honeycomb Sandwich Structures

Description: The objective of this research is to determine how the sandwich's physical characteristics have an impact on the mechanical properties, determine under what conditions the specimens will be lighter and mechanically stronger, and determine if the use of an aluminum honeycomb sandwich as a construction material is feasible. The research has aimed at the use of aluminum sandwiches as light and strong material. The study of the structural layers' damage resistance and tolerance demonstrated that th… more
Date: May 2021
Creator: Doukoure, Maimouna
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Design, Fabrication and Testing of a Novel Dual-Axis Automatic Solar Tracker System Using a Fresnel-Lens Solar Concentrator

Description: This thesis project investigates, analyzes, designs, simulates, constructs and tests a dual-axis solar tracker system to track the sun and concentrates the heat of the sunlight, using a Fresnel lens, into a small area, which is above of an evaporator, to increase the temperature of the seawater to convert it into freshwater. The dual-axis solar tracker was designed with the main objectives that the structure was portable, dismountable, lightweight, low cost, corrosion resistant, wires inside pi… more
Date: August 2021
Creator: Almara, Laura Mabel
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Embedded Sensing Textiles for Corrosion Detection

Description: Corrosion in underground and submerged steel pipes is a global problem. Coatings serve as an impermeable barrier or a sacrificial element to the transport of corrosive fluids. When this barrier fails, corrosion in the metal initiates. There is a critical need for sensors at the metal/coating interface as an early alert system. Current options utilize metal sensors, leading to accelerating corrosion. In this dissertation, a non-conductive sensor textile as a viable solution was investigated. For… more
Date: August 2021
Creator: Chowdhury, Tonoy
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Aerodynamic Optimization of a 2D Airfoil for Rotary-Wing Aircraft at Mars Atmospheric Conditions

Description: The interest toward Mars exploration has been considerably increasing due to also the successful deployment of the Perseverance rover and the continuous tests developed by SpaceX's launch vehicle, Starship. While the Mars 2020 mission is currently in progress, the first controlled flight on another planet have been proven in April 2021 with the vertical take-off and landing of the Ingenuity rotorcraft on Mars. In addition, the rotorcraft Dragonfly is expected to achieve the same endeavor in Tit… more
Date: December 2021
Creator: Saez, Aleandro G.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Fabrication and Testing of Polymeric Flexible Sheets with Asymmetric Distributed Magnetic Particles for Biomedical Actuated Devices

Description: This thesis explores a method to fabricate magnetic membranes with asymmetric distribution of particles and their testing as actuators. Focus of this research is to fabricate thin polymeric sheets and thickness range of 120-125µm, with asymmetric distribution of magnetic nano particles, employing micromagnets during the fabrication. The micromagnets are used to localize the magnetic particles during the curing process at selected locations. The effect of the asymmetric distribution of magnetic … more
Date: May 2022
Creator: Bakaraju, Megha Ramya
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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