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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
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
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
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
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
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
Partner: UNT Libraries

Real Time Gas Monitoring and Modeling on the Pyrolysis Process of Biomass

Description: In order to better understand the changes occurring in the internal environment of the pyrolysis process a method of monitoring the internal environment in real time is the key objective of this study. To accomplish this objective four tasks were laid out in order to develop an effective way of monitoring the changes in gases present as pyrolysis is occurring as well as in material activation processing. For all processing the self-activation process was used which combines pyrolysis and ther… more
Date: December 2021
Creator: Smith, Lee Miller
Partner: UNT Libraries

Green Manufacturing of Lignocellulosic Fiber through Bacterial Degradation Process

Description: Lignocellulose is the most abundant biopolymer on earth and offers excellent potential for sustainable manufacturing. Because lignocellulose is structurally complex and resistant to decomposition, innovative degradation strategies are necessary to unlock its value. In this dissertation, a green manufacturing process through enzyme-triggered self-cultured bacteria retting for lignocellulosic fiber was developed and investigated. The mechanism of the lignocellulosic fiber retting at a controlled … more
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Date: December 2023
Creator: Fu, Yu
Partner: UNT Libraries

Remotely Controlled Magneto-Phononic Devices Achieving Nonreciprocity and Anderson Localization in Ferrofluid

Description: Motivated by previous relevant research on phononics including both active and passive phononics, the interest of faster turnability and more functions of the active phononics of further study led to this proposing research topic: magnetic field tunable active functional phononics. The first design of magnetic field tunable reciprocal--non-reciprocal transmission acoustic device was established, material was characterized, and numerical simulation has been performed. The simulation results show… more
Date: December 2021
Creator: Jin, Yuqi
Partner: UNT Libraries
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