Engineering Commons^™

The Second-Order Features Adjoint Sensitivity Analysis Methodology For Response-Coupled Forward/Adjoint Linear Systems (2nd-Fasam-L): Mathematical Framework And Illustrative Application To An Energy System, Dan Gabriel Cacuci

Faculty Publications

The Second-Order Features Adjoint Sensitivity Analysis Methodology for Response-Coupled Forward/Adjoint Linear Systems (abbreviated as “2nd-FASAM-L”), presented in this work, enables the most efficient computation of exactly obtained mathematical expressions of first- and second-order sensitivities of a generic system response with respect to the functions (“features”) of model parameters. Subsequently, the first- and second-order sensitivities with respect to the model’s uncertain parameters, boundaries, and internal interfaces are obtained analytically and exactly, without needing large-scale computations. Within the 2nd-FASAM-L methodology, the number of large-scale computations is proportional to the number of model features (defined as functions of model parameters), as opposed to …

On-Demand Fabrication Of Piezoelectric Sensors For In-Space Structural Health Monitoring, Amanda White, Isaac Little, Anastasiya Artyuk, Nicholas Mckibben, Fereshteh Rajabi Kouchi, Claire Chen, David Estrada, Zhangxian Deng

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Inflatable structures, promising for future deep space exploration missions, are vulnerable to damage from micrometeoroid and orbital debris impacts. Polyvinylidene fluoride-trifluoroethylene (PVDF-trFE) is a flexible, biocompatible, and chemical-resistant material capable of detecting impact forces due to its piezoelectric properties. This study used a state-of-the-art material extrusion system that has been validated for in-space manufacturing, to facilitate fast-prototyping of consistent and uniform PVDF-trFE films. By systematically investigating ink synthesis, printer settings, and post-processing conditions, this research established a comprehensive understanding of the process-structure-property relationship of printed PVDF-trFE. Consequently, this study consistently achieved the printing of PVDF-trFE films with a thickness of …

Test And Evaluation Model For Midwater Docking Of Autonomous Underwater Vehicles, Parker Baillon

Theses and Dissertations

This research created a Test and Evaluation (T&E) model for midwater Autonomous Underwater Vehicle (AUV) capture. The creation of this model will allow for a better assessment of the feasibility of midwater AUV capture. To achieve this, the T&E model was exposed to various flow conditions to assess stability. Capturing an AUV in midwater, the area below the wave-affected zone to the sea floor, has many benefits for an AUV and its mission. AUVs basing missions from a midwater dock will not be affected by wave motions. A midwater dock can be transported to any mission site and deployed with …

Methodologies For Optimization And Surface Heat Flux Estimation For Hybrid Thermal Protection Systems, Syed Arafun Nabi

Theses and Dissertations

Thermal protection system (TPS) plays a pivotal role in safeguarding space vehicles from extreme aerothermal heating during atmospheric entry. To ensure effective thermal management, Hybrid Thermal Protection seamlessly integrating both active and passive TPS is an innovative solution. The passive TPS consists of an insulative layer on vehicle skin to counteract the aerothermal heat. Although a thicker layer enhances insulation, a trade-off arises between the thickness of the passive layer and the spacecraft’s weight. Beneath the passive TPS layer lies the active TPS functioning as a heat exchanger where the vehicle fuel liquid is considered as coolant. The effectiveness of …

Artificial Neural Networks As The Solution Of Inverse Heat Conduction Problems In Multidimensional Domains, Andrea Carolina Martinez Mundarain

Theses and Dissertations

Surface heat flux measurement is essential in various industrial applications including atmospheric entry of space vehicles, machining processes, non-destructive testing and more. While direct measurement of surface heat flux is known to be a very difficult, if not infeasible, task, acquiring temperature measurement from sub- surface locations are often viable. The problem of evaluating the surface heat flux using internal temperature measurements is known as an inverse heat conduction problem (IHCP). IHCPs are considered as mathematically ill-posed as they are highly sensitive to measurement error. This research presents a solution based on the implementation of artificial neural networks (ANNs) to …

Synthesis Of Durable Zeolite 13x Insertion Coatings And Scaled-Up Experimental Demonstration For Co2 Capture, Daniel Jamil Hocheimy

Theses and Dissertations

Minimizing the energy requirement for capturing carbon dioxide (CO₂) from post-combustion sources is critical to efficient industrial decarbonization and subsequent mitigation of the effects of climate change. The current portfolio of CO₂ capture technologies includes absorption, membrane separation and packed bed adsorption, which suffer from high energy and temperature requirements, scalability, and location dependency issues. Adsorption-based systems could cater to these concerns; however, their current embodiments primarily use packed adsorbent bed design and electricity-driven vacuum pumps to regenerate them. While simple and easy to fabricate, these designs are not scalable and cannot use heat to regenerate them …

Computational Fluid Dynamics Study Of Perforated Monopiles, Mary Kathryn Walker

Theses and Dissertations

Monopiles are used in the construction of offshore wind turbines and typically have a design life of 25 to 50 years. Over their lifecycle, monopiles are exposed to a corrosive saltwater environment, facilitating a galvanic oxidation process that quickly degrades the structure. This process can be mitigated by coating the monopile in a protective barrier and implementing cathodic protection techniques. Historically, monopile designers assumed the interior of the pile would be completely sealed and the galvanic corrosion process would eventually consume all the available oxygen, halting the reaction. However, penetrations made in the pile wall for conduit often leaked and …

Experimental And Numerical Analysis Of Laminar And Transitional Flow Through Annular Corrugated Pipes, Joseph Russell Sargent

Theses and Dissertations

This dissertation presents studies on pressure loss through annular corrugated pipes to determine a friction factor coefficient using nitrogen. Ten different corrugated pipes’ geometries were evaluated via testing and experimentation. The ratio of corrugation height to inner diameter varied from 0.233 to 0.333 and the ratio of corrugation pitch to inner diameter varied from 0.181 to 0.446. Nitrogen flow rates between 0.25 to 94.4 standard liters per minute were used, resulting in Reynolds numbers, based on the corrugated pipe inner diameter, from 100 to 23,000. The experimental set-up was validated using smooth-pipe pressure loss measurements and the derived friction factor …

Thermal Conductivity Of Thin Porous Ceramic Coatings: An Analytical And Experimental Study, Lei Zhao

Theses and Dissertations

An analytical model of the thermal conductivity of the porous yttrium-stabilized zirconia (YSZ) layer used in the thermal barrier coatings (TBCs) is presented. Such high-temperature resistant coatings are essential to protect the metallic components of gas turbine engines. The model calculates the conductivity based on the coating's porosity, pore size distribution, and pore morphology, including the individual pore cross-section area, aspect ratio, and orientation, which are extracted from the scanning electron microscopy images. The model was verified through comparisons with numerical simulation results from a multiphysics software tool. A laser temperature gradient test was performed to validate the analytical model …

Heat Sink Integrating Phase Change Materials (Pcms) For Cooling High Power Electronic Devices, Mohammad Sameer Qasem

Theses

This research explores the numerical analysis of phase change materials (PCMs) heat sinks, focusing on high heat flux dissipation applications, e.g. electronics cooling. Both 2D and 3D numerical models using gallium and paraffin RT31 as PCMs are considered within a heat sink design framework featuring a rectangular cavity and dual opposing vertical copper walls serving as fins to dissipate heat from the hot sink base that receives heat from the heat source. The inclusion of a Triply Periodic Minimal Surface (TPMS) ‘Primitive’ structure as an in-fill thermal conductivity enhancer (TCE) in the case of the gallium heat sink, and a …

Emulsion Stability, Rheological Properties, And Combustion Characteristics Of Water-Jojoba Biofuel Emulsion, Ihab Mohamed Helal

Theses

This thesis comprehensively investigates the stability, rheological properties, and engine performance implications of Water in Jojoba Biodiesel (WJBD) emulsion. The research delves into multiple aspects, including the influence of diverse surfactants and water concentrations on emulsion stability. It also yields valuable insights into the development of stable water in jojoba biodiesel emulsions, specifically tailored for diesel engines. These insights contribute significantly to the body of knowledge of positioning emulsion fuels as viable alternative to traditional diesel fuels. The anticipated benefits include notable reductions in emissions, improvement in combustion efficiency, and lower production cost. Importantly, this study underscores the critical importance …

Modeling Vibration Stiffness: An Analytical Extension Of Hertzian Theory For Angular Contact Bearings With A Thin Viscoelastic Coating, Davis R. Burton

Honors Theses

This thesis considers the novel angular contact rolling-element bearings proposed by NASA’s Glenn Research Center, which are coated with a thin solid lubricant that exhibits viscoelastic behavior. Current analytical models for the dynamic stiffness matrix of angular contact bearings, critical for vibration analysis, lack the ability to model the effects of a solid coating, as well as the time dependencies inherent in viscoelastic theory. The author first presents an overview of the stiffness matrix derivation, followed by a treatment of the underlying Hertzian contact theory. An analytical extension of this theory is proposed which accounts for a thin elastic layer …

Study Of Electrospun Nanocomposite Nanofiber Nonwoven Mats With Precursor Solutions Prepared By Ultrasonic Processing, Stephanie Tussey

All Dissertations

Understanding the complexity of changes in a polymer solution through the addition of nanoparticles and the process used to prepare the solutions is vitally important to obtain desirable characteristics of electrospun nanofibers such as degree of crystallinity, morphological, thermal and mechanical properties. Although there have been significant efforts in this research area, a more in-depth understanding on how nanoparticles can affect the formation of polymeric structures during electrospinning is still needed to ensure overall quality and performance of the nonwoven material. The present study aimed to specifically explore the relationship between solution processing method, nanoparticle volume fraction, and solution properties …

Advances In Nanofiber Technology For Biomedical Application: A Review, Dipasree Bhowmick, Islam Uddin Shipu

Mechanical Engineering Faculty Publications

The application of nanofiber technology in the biomedical field has garnered significant interest due to its potential to revolutionize areas such as tissue engineering, wound healing, and antimicrobial treatments. This paper provides a comprehensive review of the recent advancements in nanofiber technology, particularly focusing on electrospinning and 3D printing methods that enable the fabrication of scaffolds mimicking the native extracellular matrix. These technologies have facilitated the development of nanofibers with high surface-to-volume ratios, adjustable porosity, and enhanced mechanical properties, tailored to meet specific biomedical needs. Despite their promising features, challenges such as the optimization of pore size for effective cell …

Evaluation, Rating, And Numerical Modeling Of A Shock Mitigation Seat For High-Speed Craft Based On Laboratory Single Impact Testing, Darren Benn

UNLV Theses, Dissertations, Professional Papers, and Capstones

High-speed craft (HSC) are utilized in military and para-military maneuvers that are usually conducted in harsh environments. The Special Warfare Combatant-craft Crewmen (SWCC), a sub-unit of the United States Naval Special Warfare Command (NAVSOC), use an advanced HSC, known as the Combatant Craft Assault, to conduct coastal patrol and interdiction, and for infiltration and exfiltration of Navy SEALs. The United States Coast Guard, and the Drug Enforcement Agency (DEA), employ HSC for maritime patrol and to pursue ‘go-fast’ boats operated by contraband runners. In most of these intense applications, the mode of operation of the HSC results in planing. Planing …

Sliding Markov Decision Processes For Dynamic Task Planning On Uncrewed Aerial Vehicles, Trent Wiens

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Mission and flight planning problems for uncrewed aircraft systems (UASs) are typically large and complex in space and computational requirements. With enough time and computing resources, some of these problems may be solvable offline and then executed during flight. In dynamic or uncertain environments, however, the mission may require online adaptation and replanning. In this work, we will discuss methods of creating MDPs for online applications, and a method of using a sliding resolution and receding horizon approach to build and solve Markov Decision Processes (MDPs) in practical planing applications for UASs. In this strategy, called a Sliding Markov Decision …

Dynamic Impact Testing And Numerical Analysis Of Non-Proprietary Astm F2656-20 M50 Anti-Ram Barrier Components, Weston Kelley

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In a post-9/11 world, hostile actors are using vehicles as weapons to inflict civilian casualties. Pedestrians, vulnerable road users, military personnel, and police may be targeted using a vehicle as a weapon. The United States Department of Defense (DoD) also utilizes Entry Control Facilities (ECFs) which are carefully designed transportation corridors to manage how threat vehicles are able to access military facilities. In 2004, DoD started to upgrade all ECFs using both passive and active barriers. Many anti-ram vehicle barriers were evaluated according to the criteria established in ASTM F2656, but to date few options are available which are (1) …

Novel Vector Assignment Approach For Inherent Strain Modeling Of Laser Powder Bed Fusion Manufacturing, Lucas M. Morand

All Dissertations

The expansion of the design space due to additive manufacturing (AM) has been a large motivator for the success of this family of processes. Despite the complexity of the physics in metal laser powder bed fusion AM causing significant stresses and strains in finished parts, the design advantages and subsequent performance improvements continue to drive the expansion of AM. Because the trial-and-error approach to AM part development is cost prohibitive, simulation of prints has become crucial. However, full thermo-mechanical simulation is susceptible to the same pitfall of time and computational cost in order to attain part-scale results. The development of …

A Manufacturing-To-Response Pathway For Manufacturing Optimization Of Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye

All Dissertations

Over the past decade, there has been an increased adoption of thermoplastic and thermoset based continuous carbon fiber reinforced polymer (CFRP) composites for structural applications in several industries. Among the different manufacturing methods, thermoforming process for thermoplastic based continuous CFRP’s offer a major advantage in reducing cycle times for large scale productions. Similarly, out-of-autoclave curing process for thermoset based continuous CFRP’s using heated tooling enables production of large composite structures. However, these manufacturing processes can have a significant impact on the structural performance of parts by inducing undesirable effects. These effects include inhomogeneous fiber orientations, thickness variations, and residual stresses …

Oscillations Of Capillary Surfaces With Volume And Edge Effects, Dingqian Ding

All Dissertations

Capillary surfaces are defined by an interface endowed with surface tension that is partially supported by a solid substrate and are susceptible to oscillations reflecting a balance between fluid inertia and the restorative force of surface tension. The wave dynamics strongly depend upon volume change within the domain and edge effects through the boundary conditions applied at the contact-line formed at the liquid-gas-solid interface, while the spatial wave structure conforms to the geometry of the capillary surface. This dissertation develops mathematical models to address these effects for several canonical capillary surfaces, which are organized into two parts that are focused …

Characterizing The Molecular And Cellular Changes Of Senescent Cells Induced By Diverse Stressors In 2d And 3d Microenvironments, Apoorva Chauhan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aging is a risk factor for myriad diseases and is often associated with the accumulation of senescent cells. Cellular senescence, a process of irreversible cell cycle arrest, is associated with various changes in cellular morphology and function. While senescence will occur naturally in a time-dependent manner, it can be prematurely induced by various extrinsic and intrinsic factors. Most senescence studies model cell behavior in two-dimensional (2D) microenvironments; however, these models are not physiologically relevant. In this study, the effects of naturally occurring reactive oxygen species (ROS) hydrogen peroxide (H2O2) and commonly used chemotherapy drugs, doxorubicin and palbociclib, on cellular senescence …

A Computational Framework For Predicting Cell-Specific Nucleo-Cytoskeletal Forces, Madison Leigh Goldfeldt

Boise State University Theses and Dissertations

Understanding the influence of mechanical forces on cell function and fate is crucial in unraveling the intricate mechanisms that govern cellular behavior. The cytoskeleton, a dynamic network of protein filaments, plays a pivotal role in sensing and transmitting mechanical cues within cells. The nucleus relies on cytoskeletal mechanical input through nuclear envelope adaptor proteins to sense external stimuli and respond by regulating intra-nuclear chromatin organization. This research provides a means for examining the interplay between mechanical forces and the cytoskeleton in regulating various cellular processes, including cell adhesion, migration, division, and differentiation. Through studying and simulating the cellular response to …

Development And Characterization Of A Low Intensity Vibrational System For Microgravity Studies, Omor Khan

Boise State University Theses and Dissertations

The advent of extended-duration human spaceflight demands a better comprehension of the physiological impacts of microgravity. One primary concern is the adverse impact on the musculoskeletal system, including muscle atrophy and bone density reduction. Ground-based microgravity simulations have provided insights, with vibrational bioreactors emerging as potential mitigators of these negative effects. Despite the potential they have, the adaptation of vibrational bioreactors for space remains unfulfilled, resulting in a significant gap in microgravity research. This paper introduces the first automated low-intensity vibrational (LIV) bioreactor designed specifically for the International Space Station (ISS) environment. Our research covers the bioreactor's design and characterization, …

Porcine Computational Modeling To Investigate Developmental Dysplasia Of The Hip, Chia-Yu Yu

Boise State University Theses and Dissertations

While it is well-established that early detection and initiation of treatment of developmental dysplasia of the hip is crucial to successful clinical outcome, research on mechanics of the hip joint during healthy and pathological hip development in infants has been limited. Quantification of mechanical behavior in both the healthy and dysplastic developing joints may provide insight into the causes of developmental dysplasia of the hip and facilitate innovation in treatment options. In this study, subject-specific three-dimensional finite element models of two pigs were developed: one healthy pig and one pig with induced dysplasia in the right hindlimb. The objectives of …

Thermal-Fluid And Optical Considerations In The Design Of Porous Cavity Receivers, Koda D. Boldt

Boise State University Theses and Dissertations

Concentrated solar power (CSP) is a versatile renewable energy source that cleanly provides thermal energy by means of concentrating solar irradiance. One form of CSP, central receiver systems (CRS), utilizes receivers that allow for a solid medium to act as a heat exchanger between the solar irradiance and an optically clear working fluid. This solid medium can take many forms. One such form that shows great potential in high temperature applications is a porous receiver made of a ceramic material. The porous media is subject to solar irradiance to heat its surface. Air is then pulled across the porous media …

Multiscale Design And Numerical Modeling Of A Porous Lattice For Concentrated Solar Thermal Applications, Aidan T. Mcconnehey

Boise State University Theses and Dissertations

Due to the rising demand in the market for renewable energy, concentrated solar power (CSP) systems are increasing in popularity. One CSP receiver configuration showing increased promise is the volumetric cavity solar receiver, which employs a porous lattice for radiative heat absorption and transport. However, due to the presence of large temperature gradients, mechanical failure as a result of thermal expansion is a crucial metric in the design of these systems.

This thesis involves the design of a porous lattice, constrained by thermal transport requirements as well as mechanical failure criteria. The design is then numerically analyzed to determine thermal …

The Effect Of Extended Saltwater Absorption And Uv Cure On The Compressive Properties Of Msla 3d-Printed Photopolymer Resin Samples With Printing Variations, Suzanne Dixon

Theses and Dissertations

Liquid Crystal Display (LCD) 3D printers, also known as Masked Stereolithography Apparatus (MSLA), is a type of vat polymerization printing technique that cures liquid resin into a solid object. This technique is relatively new. Consequently, there is a shortage of detailed research on the impact of long-term environmental exposure on the MSLA-printed materials. The research within this document informs engineers and scientists of resin compressive properties after extended exposure to saltwater and ultraviolet (UV) light. Saltwater absorption of the material was analyzed at atmospheric pressure, 30-psi, 60-psi, and 90-psi; the samples reached saturation in saltwater after 56 days. The variation …

Fabrication And Performance Demonstration Of Compact Adsorption Heat Pump, Faraz Ege

Theses and Dissertations

Addressing global environmental concerns requires a shift to eco-friendly energy sources, particularly in cooling applications where traditional vapor-compression systems rely on harmful refrigerants and electricity. Thermally-driven cooling systems, like adsorption heat pumps, offer promise with their environmentally friendly refrigerants such as water and use of low-temperature heat sources, including solar energy or waste industrial heat. This dissertation undertakes a comprehensive investigation into the development and optimization of compact adsorption heat pumps, aiming to address the efficiency and environmental challenges inherent in conventional cooling systems.

This research begins by introducing a novel insertion coating technique for fabricating MIL-101 (Cr) adsorbent layers …

Evaluation Of Beach-Fx — Beach Nourishment Planning Model – Miami Beach Case Study, Brennan Chase Banks

Theses and Dissertations

Miami Beach, located on the Southeast coast of Florida, is a concerning location for coastal erosion because of the increasing intensity and frequency of tropical storms, nuisance flooding, and accelerated sea-level rise due to climate change. Miami Beach is famous for its beautiful beaches, making it a location of high interest for tourists, citizens, and investors. It is vital for coastal practitioners to accurately model coastal processes, beach evolution, and storm damage during the planning stage of coastal protection projects. The U.S. Army Corps of Engineers developed the Beach-fx model as a tool for engineers, planners, and economists to …

System Identification For Motion Control Of Unmanned Aerial Vehicles Platform, Raj Ramesh Agarwal

Theses and Dissertations

Comprehensive research on Unmanned Aerial Vehicles (UAV) system identification for motion control parameters is presented in this thesis, with a focus on the necessity of precise control and improved performance. Using Pseudorandom Binary Sequence (PRBS) and Normally Distributed Random Numbers, it presents a unique technique for excitation of UAV dynamic systems. It also shows how effective random signals are in time-domain identification for precise control in a range of flying circumstances. The piece of research includes a thorough analysis and implementation of various approaches and its further improvements, highlighting the benefits and drawbacks of each. These approaches include the free …