Digital Commons Network^™

Development Of Alternative Air Filtration Materials And Methods Of Analysis, Ivan Philip Beckman

Theses and Dissertations

Clean air is a global health concern. Each year more than seven million people across the globe perish from breathing poor quality air. Development of high efficiency particulate air (HEPA) filters demonstrate an effort to mitigate dangerous aerosol hazards at the point of production. The nuclear power industry installs HEPA filters as a final line of containment of hazardous particles. Advancement air filtration technology is paramount to achieving global clean air. An exploration of analytical, experimental, computational, and machine learning models is presented in this dissertation to advance the science of air filtration technology. This dissertation studies, develops, and analyzes …

Design, Development And Evaluation Of The Ruggedized Edge Computing Node (Recon), Sahil Girin Patel

Theses and Dissertations

The increased quality and quantity of sensors provide an ever-increasing capability to collect large quantities of high-quality data in the field. Research devoted to translating that data is progressing rapidly; however, translating field data into usable information can require high performance computing capabilities. While high performance computing (HPC) resources are available in centralized facilities, bandwidth, latency, security and other limitations inherent to edge location in field sensor applications may prevent HPC resources from being used in a timely fashion necessary for potential United States Army Corps of Engineers (USACE) field applications. To address these limitations, the design requirements for RECON …

Molecular Dynamics Of High Temperature Hydrogen Attack, Mike Travis Bodden Connor

Theses and Dissertations

High temperature hydrogen attack (HTHA) is a damage mechanism that only affects carbon steel and low alloy material. Most of the data regarding HTHA are experimental-driven. Even though this approach has been successful, there are still much more things that the oil and gas industry does not understand about HTHA. The regions that were considered safe (below the Nelson curves) have experienced catastrophic failure. Our research consists of performing Molecular Dynamics (MD) and the Nudge Elastic Band (NEB) calculation of HTHA to better understand the atomistic behavior of this damage mechanism.

Numerical Study Of Advanced Solar Receiver Tubes Based On A Coupled Thermo-Mechanical Analysis For Concentrated Solar Power Tower Plant, Shawn Michael Hatcher

Theses and Dissertations

The search for more sustainable energy to match the growing energy demand begins with finding more dispatchable resources such as solar energy. As one of the promising solar technologies, concentrated solar power (CSP) has a full capacity to store thermal energy for extended operation. Nevertheless, some key components in CSP systems usually face extreme environment, such as uneven solar flux, cyclic thermal expansion, structural degradation on the solar absorber tubes in a Concentrated Solar Power Tower (CSPT) Plant. In this study, we applied Multiphysics simulation to explore the benefits of introducing optimized fins for heat transfer enhancement and uniform temperature …

A Constitutive Material Model For Simulating Texture Evolution And Anisotropy Effects In Cold Spray., Creston Michael Giles

Theses and Dissertations

Cold spray has seen rapid advancement since its inception and has shown significant potential as a method of additive manufacturing. However, the large plastic deformation and repeated heating/cooling cycles that the material undergoes during the cold spray process can result in gradients in material structure and large residual stresses. The purpose of this study is to extend the existing EMMI material model to include anisotropic material response through the use of orientation distribution functions to predict residual stresses and anisotropy resulting from cold spray and similar additive manufacturing processes. Through the use of a finite element simulation, yield surfaces for …

Design, Development, And Control Of A Robotic Gripper For Activities Of Daily Living (Adl) Assistance., Jaime Rafael Hernandez

Theses and Dissertations

This research contributes to developing a robotic gripper designed to improve the performance of assistive robots to help people with upper limb impairment due to stroke, injury, and other trauma. As developed in this research, the gripper for assistive robots (GAR) can be an alternative solution to the existing robotic grippers increasing the benefits in different ways, including the cost/benefits ratio and the range of graspable objects.

The GAR has been designed with simplicity in mind with a minimum viability approach. The design, construction, control, and operation of this robotic hand have been simplified with a minimal number of custom-made …

Mechanical Erosion Investigation Through The Solid Rocket Motor’S Nozzle, Mohamed Ahmed Abdelazim Abousabae

Theses and Dissertations

The solid rocket motor (SRM) is considered one of the essential engines that facilitatesaerospace research; thus, investigating the propellant burning process is vital. One of the challenges facing its growth is the oxidization of the aluminum into aluminum oxide at the exhaust’s high pressures and temperatures. The oxidized aluminum forms agglomerates, impinge on the exit nozzle walls, causing severe damage (erosion) to the nozzle material. Thus, the present work attempts to investigate and reduce this erosion. Two different approaches are followed in the current work, the first one aims to better understand the aluminum oxide agglomerates break-up mechanism and the …

Study Of The Various Charactertics Of A Helical Vertical Axis Wind Turbine Compared To A Straight Bladed Darrieus Design, Patrick Quinlan

Theses and Dissertations

As the wind energy market continues to expand, the need for a more diverse range of wind turbine technologies becomes increasingly apparent. Horizontal axis wind turbines (HAWT) have become the standard design for wind turbines over the past few decades and have been the go-to design used in wind farms both on land and off-shore. However, in residential and urban environments other types of turbine designs can help expand the reach of wind energy. Specifically, vertical axis wind turbines (VAWT) have shown potential for new applications of wind turbines in areas that are less suitable for typical HAWTs. The most …

The Deflection And Heat Transfer Analysis Of Injection Mold Cavity With Sla Cooling Channel Insert, Olumide Temidayo Aladesiun

Theses and Dissertations

Fast cooling in injection molding is the critical in the process economy. Among many different cooling channel designs available, conformal cooling offers the best and the most efficient cooling. However, limited awareness, accessibility, complexity, cost, knowledge, and experience limit the use of conformal cooling channels to be used into the mold in a molding process.

Typically, SLM(Selective Laser Melting) method is used to create cavity inserts with conformal cooling channels, however, due to the difficulties listed above, applications of conformal cooling channels are very limited. For an inexpensive alternative SLA (Stereolithography Apparatus) can print cavity inserts with conformal cooling channels. …

Femtosecond Pulse Filamentation In Dielectric Media Toward Photonics Sensor Fabrication, Anitha Narayanan

Theses and Dissertations

Through pulse filamentation, femtosecond laser pulses have been utilized to modify the refractive indices of dielectric materials such as glass, A-plane sapphire crystal, and Cplane sapphire crystal. The 10x Infinity Corrected Lens was used, and the focusing condition was tuned as being the same and fixed to both glass and sapphire crystals. First, 8uJ of laser energy was optimized to produce controlled pulse filamentation voids in the glass. The laser intensity was then optimized to 2-3.5 uJ, 1.5 uJ, & 2.5 uJ, respectively, for the controlled pulse filamentation in A and C plane sapphire crystals. Due to the different crystal …

Investigation Of Process Parameters To Fabricate Refractory Medium-Entropy Alloy By Selective Laser Melting Process, Abdullah Al Masum Jabir

Theses and Dissertations

This thesis proposal investigates the synthesis of TiWMo refractory medium entropy alloy (RMEA) by selective laser melting process from elemental powder. Steel, titanium and tungsten substrates were used to study the impact on the formation of TiWMo RMEA. Different process parameters were applied to investigate the effects on melting, diffusion and formation of RMEA. The microstructure of TiWMo and elemental distribution were observed by scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). SEM analysis revealed that with higher energy density the pores and microcracks were improved. EDS data validated the composition is homogenized and stable after few layers …

Tympanostomy Tubes In Children: A Fem Study Of Adverse Effects, Manuel Nicolas Jaramillo Bucheli

Theses and Dissertations

Background: The current study investigates if tympanic (myringotomy) tubes affect hearing by comparing the harmonic displacement response to sound excitation within the hearing frequency range for healthy vs. surgically-treated pediatric tympanic membranes. The use of ear myringotomy tubes has proven an effective method for combating recurrent ear infections in infants and children. These tubes are placed in the tympanic membrane through an incision and connect the middle ear to the external ear, thereby allowing fluid drainage and middle-ear ventilation. While this treatment has been proven beneficial in alleviating urgent pus accumulation in the middle ear, recent research shows that it …

A Numerical Simulation Of The Powder Bed Additive Manufacturing Process With Molecular Dynamics Simulation, Yeasir Mohammad Akib

Theses and Dissertations

Many manufacturing industries utilize powder bed fusion (PBF) since it can produce microscale precision 3D parts. During PBF, powder particles are selectively fused layer by layer using thermal energy. The build quality in the PBF process relies heavily on powder bed properties and thermal energy deposition. Powder flowability, spreadability, and packing fraction are some of the insightful factors that determine the quality of the powder bed. In this study, a two-dimensional powder bed is developed using the LAMMPS package. A cloud-based pouring of powders with varying volumes and initialization is adopted for the work. A blade-type and circular recoater is …

Development Of An Electro-Centrifugal Spinning Setup For Nanofiber Production Research, David A. Treviño

Theses and Dissertations

Nanofiber production methods have been developed and improved over the course of decades. Each process allows for the creation of fibers with distinct properties that provide benefits to growing number of applications. On the same note, every process has shortcomings that keep them from being universally valid for all applications. This research considers electrospinning and centrifugal spinning systems and attempts to create a process which maintains high fiber qualities like small and consistent fiber diameters, and improved fiber alignment while providing a high fiber yield. The electro-centrifugal (EC) spinning machine that resulted was designed utilizing computer aided design (CAD) software …

Wheelchair-Mounted Assistive Robot For Activities Of Daily Living: Design, And Validation, Elias Jose Munoz Montenegro

Theses and Dissertations

In the last decades, the number of wheelchair users has been increasing at an alarmingrate. Part of these individuals has an upper or lower dysfunction (ULED) resulting from a stroke, spinal cord injury, trauma, accident, or workplace injuries. Due to this, these patients need assistance to conduct their activities of daily living (ADLs). Hence, Wheelchair-Mounted Assistive Robots (WMAR) have a crucial role in Individuals with ULED. This research focuses on the design optimization, development, and validation of WMARs for essential ADLs. The design aims to obtain the link lengths with the most workspace coverage. Moreover, the analysis includes singularity avoidance …

Study Of The Various Charactertics Of A Helical Vertical Axis Wind Turbine Compared To A Straight Bladed Darrieus Design, Patrick Quinlan

Theses and Dissertations

As the wind energy market continues to expand, the need for a more diverse range of wind turbine technologies becomes increasingly apparent. Horizontal axis wind turbines (HAWT) have become the standard design for wind turbines over the past few decades and have been the go-to design used in wind farms both on land and off-shore. However, in residential and urban environments other types of turbine designs can help expand the reach of wind energy. Specifically, vertical axis wind turbines (VAWT) have shown potential for new applications of wind turbines in areas that are less suitable for typical HAWTs. The most …

Fabrication Of Solar Absorber Tube With Internal Fin Structure With In718 And Effect Of Boron With In718 For Solar Absorber Tube Using Selective Laser Melting 3d Printing Technology, Naznin Nuria Afrin

Theses and Dissertations

This research aimed to fabricate Solar Absorber Tubes for Solar-Thermal Power Plant with internal fin structures using Selective Laser Melting (SLM) technology. In this study, we investigated the effect of B with IN718 in 3D printing using SLM for solar absorber tubes. The objective was to study the material-process-properties relationship with goal to identify and validate the optimal parameters for the SLM process. Material selected for this study was IN718 with 0.5% and 1% B particle mixed using a V-shape mixing machine. The flowability test was conducted using the Angle of Repose (AOR) method. 3D printed samples …

Fabrication And Characterization Of Force Spun Polymeric Nanofiber For Drug Delivery And Tissue Engineering Applications, Salahuddin Ahmed

Theses and Dissertations

This study focuses on the development and characterization of polymeric nanofiber for drug delivery and tissue engineering applications. In this study, poly(lactic-co-glycolic) acid (PLGA), Poly-vinyl alcohol (PVA), and Pullulan(PL) were used as the base polymers to develop the nanofiber. Bioactive components Oleanolic acid(OA), Oxymatrine(OM), and Salvianolic Acid(SA) were incorporated in PLGA, PVA, and PL, respectively, via solution mixing. The nano fiber systems were developed using the Forcespinning® method. Morphological, thermo-physical, and biological properties of the fiber mats were analyzed. The composite fiber system containing OA showed a very high drug loading efficiency. The composite fiber system containing high concentration of …

Ultrafast Laser Direct Writing Of Conductive Patterns On Modified Polyimide Film For Flexible Electronic Applications, Ishrat Jahan Biswas

Theses and Dissertations

Conductive patterns can be printed on a flexible polymer substrate using the direct laser writing (DLW) method. In order to write conductive circuits in such polymer using a laser, polyimide (PI) is a desirable material choice due to its electrical, chemical, and mechanical properties. Electrically non-conductive PI has shown great potential for flexible printed electronics as LDW enables selective carbonization in the bulk of such material leading to the formation of conductive lines. The technique is shown to be a rapid and minimal cost method for printing electrodes to nanoscale devices. However, investigations in this field show several limitations to …

A Study Of The Surface Properties Of Additive Manufactured Inconel 718 After Laser Surface Treatment And Cnc Grinding, Sampson K. Canacoo

Theses and Dissertations

This study investigated the surface properties of additive manufactured Inconel 718 produced through selective laser melting, and the effects of laser ablation and CNC grinding on the surface finish. The objectives were to investigate the effects of the various parameters of laser ablation and CNC grinding on the Inconel 718 surface. The parameters used for the laser experiments were pulse energy (4, 20, and 30 µJ), scanning speed (5, 10, and 15 mm/s), and hatch distance (10, 30, and 50 µm). For the grinding experiments, the wheel speed was kept constant at 20.3 m/sec, however, two different workpiece speed (8.6 …

Development Of Vegetable Oil-Based Nano-Lubricants Using Ag, H-Bn And Mgo Nanoparticles As Lubricant Additives, Kollol Sarker Jogesh

Theses and Dissertations

Because of the harmful impact of petroleum-based lubricant on the environment and human body, vegetable oil-based lubricant with eco-friendly nanoparticles has a great potential to be an alternative lubricant if it possesses proper lubricating properties. In this study, thermal conductivity, viscosity and tribological properties (wear scar diameter and coefficient of friction) of vegetable oil-based nanolubricant, developed from soybean oil and sunflower oil, modified with Ag, h-BN and MgO nanoparticles as lubricant additives, were evaluated. For thermal conductivity evaluation, a line heat source method was used with KD2 Pro-Thermal Property Analyzer. For viscosity evaluation, Haake Mars 40-rheometer was used to evaluate …

Feasibility Analysis Of Embedding Optical Fiber Sensor Into Additively Manufactured Part, Mahmudul Hasan Porag

Theses and Dissertations

The research tried to examine the viability of the embedment of optical fiber sensors in Additively built components, packaging the sensors within the components, and characterizing the sensors for sensing a specified measurement. Optical fiber sensors are popular due to their small size, resilience against electromagnetic radiation, and reliability in potentially dangerous conditions. Embedding fibers inside a product allows for the monitoring of critical areas, allowing for preemptive action in the case of a breakdown. Coupons of Inconel 718 were made using laser powder-bed fusion (LPBF), with the fabrication settings tuned to determine whether such a development was possible. After …

The Effect Of Zonation, Biofouling, And Corrosion Products On Cathodic Protection Design For Offshore Monopiles, Caglar Erdogan

Theses and Dissertations

Cathodic protection (CP) is required to prevent corrosion of the submerged steel for offshore wind monopile foundations in the marine environment. The design of these systems depends on the environmental conditions, including temperature, salinity, pH, dissolved oxygen, depth, micro- and macro-organisms, and water flow rates. The standards utilized to design cathodic protection systems consider only some of these conditions. This research identified the gaps in knowledge for the design of corrosion prevention systems for offshore wind monopile foundations and investigated the changes in cathodic current densities due to macro-galvanic cells, fouling communities and corrosion products established on uncoated vertical steel …

Framework For The Utilization Of The Agile Methodology In Engineering Consulting Services, Cristian Daniel Nuñez

Theses and Dissertations

The guidelines that form the Agile methodology framework are developed and adapted to the engineering consulting services industry. Four tools recommended by the literature are developed and adapted for the specific case of this industry. The implementation of the use of these tools is intended to help adopt the Agile methodology more effectively. A company that performs consulting services for airports is taken as a case study. This company did not officially implement the Agile methodology at the time this research has been done. The data is obtained through a survey designed to associate the company's activities with the guides …

Thermal Design And Energy Analysis Of A Greenhouse In Microgravity Conditions, Nivedha Karigiri Madhusudhan

Theses and Dissertations

The recent progress in commercial space flights and prospects for interplanetary space missions has attracted more attention towards developing sustainable built environments in microgravity conditions. An important factor in establishing a sustainable living condition for outer space applications is the ability to produce food. The thermal design considerations in a greenhouse have a major impact on the survival, water efficiency, quantity, and quality of plants produced. The extremely low environmental temperatures necessitate the use of heaters which do consume energy. Given the scarcity of energy access, it is important to achieve proper thermal conditions with the lowest possible energy requirements. …

Investigation Of Polymer Nanocomposites With Silicon Dioxide Fillers As Helium Cooled High-Temperature Superconducting Cable Dielectrics, Jordan Thomas Cook

Theses and Dissertations

In this thesis, three polymer nanocomposite configurations are fabricated for investigation as dielectrics in helium-cooled high-temperature superconducting (HTS) cables. Polyimide, polyamide, and polymethyl methacrylate are utilized as host polymers. The composite samples are synthesized through an in situ process, dispersing silicon dioxide nanoparticles throughout the polymer hosts. Fourier transform infrared spectroscopy and scanning electron microscopy were employed to validate the synthesis of each composite configuration. Thin film samples of each configuration were also tested for their dielectric strength at both room (300 K) and cryogenic (92 K) temperatures. When going from room to cryogenic temperatures, all materials demonstrated a significant …

Experimental Investigations Of Yarn Pull-Out Behavior In Kevlar®: Influence Of Applied Metallic Coatings And Effect Of Dynamic Loading, Julie Ann Roark

Theses and Dissertations

Flexible woven Kevlar® textile fabrics are widely used in protective armor applications. Yarn pull-out, comprised of yarn uncrimping (i.e., straightening) and yarn translation, is a major energy absorption mechanism during ballistic impact onto these fabrics, especially for impact velocities below the ballistic limit. Yarn pull-out is influenced by various parameters including inter-yarn friction, pull-out distance, pull-out velocity, transverse pre-tension, fiber diameter, fabric architecture, fabric waviness, fabric count and yarn modulus.

The first part of this thesis investigates yarn pull-out behavior of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride, silver) via a directed vapor …

A Hybrid Experimental-Computational Study: Prediction Of Flow Fields And Full-Field Pressure Distributions On Three-Tab Asphalt Roofing Shingles Subjected To Hurricane Velocity Winds, Troy A. Myers

Theses and Dissertations

A novel hybrid experimental-computational study is performed to predict the flow fields and pressure distributions on the measured shapes of flexible, three-tab asphalt roofing shingles undergoing increasing uplift when exposed to hurricane velocity winds. StereoDIC analysis is performed to measure the transient full-field deformed shapes of full-size three-tab asphalt shingles when subjected to hurricane velocity winds for two hours. Steady state computational fluid dynamics (CFD) simulations of the shingled roof facsimile-plenum region representative of the experiments are successfully performed. The simulations are performed to predict wind loading of the uplifted shingle shapes by utilizing the measured full-field three-dimensional uplifted shapes …

Towards Modeling Of Induction Welding Of Thermoplastic Laminates With A Mixed Finite Element Boundary Element Approach, Florentius Johannes Van Zanten

Theses and Dissertations

There is an increased interest in induction welding of carbon fiber reinforced thermoplastic composite laminates within the aerospace industry. Currently, optimal manufacturing process parameters (e.g., current, power, and frequency settings, coil movement speed, etc.) are determined through an experimental trial-and-error approach. To reduce the need for an experimental approach that can determine the manufacturing process parameters, which would be expensive in both time and money, accurate and computationally efficient numerical tools are desired. This research is focused on improving the existing numerical tool, WelDone, in regard to its speed and accuracy.

WelDone utilizes a hybrid element formulation that combines traditional …

High-Throughput Computation Of Interfacial Thermal Management Of Wide-Bandgap Semiconductors, Hao-Wen Chen

Theses and Dissertations

As semiconductor electronics, in particular high electron mobility transistors, get hot in operation, people are trying to incorporate different semiconductor materials to solve the problem of heat dissipation to maintain the device efficiency and performance. In this master thesis, two different packages, LAMMPS and almaBTE, that are focusing on micro-scale and atomic scale respectively, are used to simulate the heat transfer process across interfaces in two different scales. In the LAMMPS simulation, the research is exploring how the location of atoms and the thickness of interfacial layers will influence the interfacial thermal conductance. On the other hand, using the almaBTE …