Engineering Commons^™

Investigating The Role Of Cryptochrome Activity In Arabidopsis Plant And Blue Light Exposure In Saos-2 Cell-Mediated Mineralization, Maria Nijr Albaqami

Theses and Dissertations

Cryptochromes (CRYs) are flavoproteins that absorb blue light and are associated with the perception of electromagnetic stimuli in a variety of organisms including animals and plants. When exposed to blue light, CRYs undergo flavin redox cycles and form radical pairs intermediates that are assumed to be magnetically sensitive as predicted by the radical-pair hypothesis. However, it is unknown if CRYs fulfill the criteria to act as biological magnetosensors. In the first aim, Arabidopsis thaliana seedlings were exposed to blue light and a time-dependent weak magnetic field at radiofrequency (RF) of 7 MHz as a diagnostic tool to test the radical-pair …

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 …

Image-Based Cancer Diagnosis Using Novel Deep Neural Networks, Hosein Barzekar

Theses and Dissertations

Cancer is the major cause of death in many nations. This serious illness can only be effectivelytreated if it is diagnosed early. In contrast, biomedical imaging presents challenges to both clinical institutions and researchers. Physiological anomalies are often characterized by modest modifications in individual cells or tissues, making them difficult to detect visually. Physiological anomalies are often characterized by slight abnormalities in individual cells or tissues, making them difficult to detect visually. Traditionally, anomalies are diagnosed by radiologists and pathologists with extensive training. This procedure, however, demands the participation of professionals and incurs a substantial expense, making the classification of …

Modeling And Validation Of Common-Mode Emission In Silicon Carbide Based Voltage Source Converters, Tianchen Li

Theses and Dissertations

Electromagnetic compatibility (EMC) issues have become one of the most difficult challenges in power converter designs. With the invention of wide bandgap (WBG) power semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) power MOSFETs, the power converter designs are provided with the potential to be significantly more power dense than older generation converters using silicone IGBTs. However, the majority of spectral contents of the switching waveforms are moved from the very-low-frequency (VLF, 3 kHz to 30 kHz) range to low-frequency and up to the very-high-frequency (VHF, 30 MHz to 300 MHz) range. Moreover, due to the design traits …

Stress-Based Topology Optimization Of Pi Preform-Bonded Composite Laminate Structure, Iwan Broodryk

Theses and Dissertations

The purpose of this work is to explore the stress-based topology optimization of structure that utilizes laminated composites and 3D woven Pi preform joints. Simple geometry, loading, and boundary conditions are considered. At a finite element level, an aggregate stress ratio is developed for Pi joint and acreage laminate elements. A basic descent method of moving asymptotes (BDMMA) algorithm is created to solve all optimization problems. Topology results for two different stress-based formulations and a compliance minimization problem are compared, followed by an in-depth analysis at a Pi joint and laminate level.

Accelerated Aging Of Adhesively Bonded Composite Joints For Use In Material Screening And Selection During Development: A Review And Case Study, Marie Danielle Flanigan

Theses and Dissertations

Adhesively bonded structures are used in many high-tech industries such as aerospace, automotive, and defense. The application of these joints using composite adherends has increased in recent years because of improved strength-to-weight ratio, design flexibility, and lower concern for corrosion. Quality acceptance of these structures largely depends on reliability and durability which includes influence of environmental service conditions on long-term behavior. Characterization of long-term behavior presents a difficult challenge to those involved in material selection and design due to the long service life of the joint compared to the development time available and complexity of the degradation mechanisms. Therefore, different …

Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro, Sean Gregory Gunther

Theses and Dissertations

This document finds the stability and control affects of electric powerplant conversion on a pre-existing internal combustion powered Pipistrel Virus SW through comparison with the Pipistrel Velis Electro. Testing included analysis of both static and dynamic stability on the longitudinal and lateral-directional axes of the airplane. Due to the light sport airplane being used in testing, some of the intedended tests were unable to be performed, however, conclusions were still capable of being made. The primary conclusion is that electric conversion of an airframe has no significant negative consequences, with the airplane still exhibiting positive stability on all three axes. …

Examining The Effects Of Payload Type And Framing On Weather-Related Decision-Making In A Simulated Urban Air Mobility (Uam) Environment, Maria Chaparro Osman

Theses and Dissertations

The purpose of the current research study was two-fold. First, the study examined the effect of payload type on the riskiness of weather-related decision-making in a simulated urban air mobility (UAM) environment. Second, the current study examined whether framing information using prospect theory (Kahneman & Tversky, 1979) could influence the riskiness of weather-related decision-making in a simulated UAM environment. In the context of the current study, riskiness referred to the risk associated with the decision outcome, specifically whether participants selected a risk-averse decision outcome (return to the departure site) or risk-seeking decision outcome (continue to the destination site) based on …

Piper Pa-28-181 Archer Iii Tail #931ec Flight Test Stability, Control And Performance, Steven Allan Sutton

Theses and Dissertations

The following flight test was conducted as part of the culmination requirement for the Master of Science, Flight Test Engineer degree program from Florida Institute of Technology. The flight was conducted to gather data and produce a flight test report on the data gathered. The flight test plan consisted of a series of both Stability and Handling test point as well as basic aircraft performance points. The testing was planned to be accomplished over a single flight, for reasons discussed later in this report. The flight departed on the morning of 26 September, 2022 out of Bob Sikes Airport, KCEW, …

Building Software Compliant Multidimensional Datasets Through Programmatic Solutions, Jon Enoch Jones

Theses and Dissertations

Meteorological and other multidimensional, georeferenced data is used extensively in science and engineering. These datasets are produced, shared, and used by organizations all over the world. Conventions have been developed specifying the metadata and format of these datasets in an effort to standardize the data and make it compatible with current and future software and web services. By necessity, the conventions are complex and difficult to implement correctly, resulting in useful datasets that are unusable in many applications due to lack of compliance with the conventions. By programmatically assigning metadata and guiding the dataset creator through the dataset creation process, …

Towards Orchestration In The Cloud-Fog Continuum, Xavier Jesus Merino Aguilera

Theses and Dissertations

The proliferation of the Internet-of-Things has raised demand for computing, storage, and network resources. The cloud model is ill-equipped to handle the volume and variety of data travelling to and from the cloud’s core as more data is generated and consumed at the network’s edge. Some applications necessitate low-latency connectivity and geographical awareness, highlighting the cloud’s centralization shortcomings. By localizing resources, minimizing bandwidth utilization, and lowering latency, the fog and edge layers are proposed to circumvent these limitations. At these layers, resource orchestration is crucial because poor resource management has an impact on service delivery. The aim of this study …

Deep Learning Approach To Speech Recognition: A Signal Extractor & Producer For Artificial General Intelligence, Ahmad Zuhair S. Hasanain

Theses and Dissertations

The efficient use of a communication bandwidth starts with the data source. The features of the speech signals can be extracted and reconstructed to lower the Internet traffic of the acoustic artificial agents and to increase the quality of the automatic speech recognition systems. The Speech Quefrency Transform (SQT) is hereby introduced in the work to enrich the communication space between the artificial agents and mankind. We describe the motivation, methodology, and deep learning approach in detail as we apply the SQT technology to several applications: sharp pitch track extraction, real-time speech communications, and emotion recognition. The results were excellent. …

A Voice And Facial Recognition System To Protect Students From Being Forgotten Inside School Buses In The Kingdom Of Saudi Arabia, Ibrahim Alferaih

Theses and Dissertations

In this research, we discuss the situation of students in the three to eight year old age group. Every day in the Kingdom of Saudi Arabia during school days, more than 1,000,000 students are transported throughout the country by more than 15,000 school buses. Everything is dependent on the human element. During school transportation around the world, many children are forgotten inside the school bus and with many of them eventually going missing or even dying. The bus driver is usually busy and tired due to the focus on the road, which may make him lose focus on those on …

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 …

Integrating Model-Based Systems Engineering Industry Transformations For Workforce Development, Wilma Analisa Ankobiah

Theses and Dissertations

This study explores whether MBSE industry workforce requirements are being satisfied by the academic curricula of US institutions. Using an industry survey, which is highlighted in Chapter 3, identifies the existing perception of MBSE from various industries and explores the MBSE needs of professionals, such as tools concepts and languages. It examines how industry professionals perceive MBSE, the advantages and challenges of MBSE use and the preferred MBSE tools, languages and knowledge of concepts deemed necessary to ensure project success in the respective industry sectors. Results of phase 1 industry survey will summarize the current MBSE concepts, tools and languages …

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. …

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 …

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 …

Ambient Air-Processed Cspbi3-Based Perovskite Solar Cell Via Semi-Sputtering Deposition And Numerical Studies Of Cs3sb2i9-Based Perovskite Solar Cell, Shamik Datta

Theses and Dissertations

Commercialization of Perovskite solar cells as a clean energy source can augment the reduction of carbon footprint. CsPbI3, a well-known perovskite material, has been synthesized in ambient air and high-humidity conditions and utilized as the active layer in a perovskite solar cell. The rest of the solar cell layers have been sputter-deposited. This solar cell with a p-i-n configuration ITO/NiOx/CsPbI3/ZnO/Au exhibited a champion efficiency of 3.7%. Nonetheless, lead incorporation in the conventional Pb-cation-based perovskites poses an environmental threat. The physical proximity of living organisms to lead point sources exhibits a wide spectrum of negative consequences. In this study, we have …

Safety-Aware Longitudinal And Lateral Control Of Autonomous Vehicles, Randy Guadalupe Chapa

Theses and Dissertations

Safety is undoubtedly the most critical design requirement regarding autonomous vehicle controllers. This research considers an autonomous vehicle to keep a desired distance from the leader vehicle, as well as stay centered within the lane. To achieve this, the lateral control problem and the combined longitudinal and lateral control problem were studied. Adaptive control laws were proposed with the aid of the backstepping technique and the barrier function technique. Simulation was done to verify the effectiveness of the proposed control laws.

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 …

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 …

Effects Of Fibers In Dense Graded And Gap Graded Asphalt Concrete, Franher Daniel Cantu

Theses and Dissertations

As a part of efforts to understand the interactions between fibers and particles in compliant binder such as asphalt. This investigated the compressive behaviors of fiber reinforced asphalt concrete with different aggregate gradation, such as gap graded and dense graded. There have been multiple studies attempting to understand the impact of fibers on particle reinforced composites, however, only few of those focused on the fiber-particle interactions. A comprehensive literature review on the current state of the art of fiber reinforced asphalt concrete and fiber-particle interactions was conducted. Then a series of compression tests were conducted using various size steel fibers …

A Study Of The Constitutive Models Used In Analyzing Dynamic Strain Aging In Austenitic Stainless Steel 304, Mohammad Mohiuddin

Theses and Dissertations

When triggered, dynamic strain aging has a significant impact on the microstructural mechanical behavior of austenitic stainless steel 304 high performance alloy. The dynamic strain aging phenomenon has been shown to cause significant additional hardening in several experimental studies. To effectively predict the behavior of the material, it is required to employ a constitutive model that includes dynamic strain aging. The extra hardness brought on by dynamic strain aging is captured in this study by the proposal of a novel constitutive model (VAS model) for Austenitic Stainless Steel (ASS) 304 high performance alloy. As part of this study, the developed …

Fostering Collaboration In Emerging Three-Tiered Spectrum Markets, Anindo Mahmood

Theses and Dissertations

Ensuring optimum spectral efficiency is a critical requirement for current wireless networks to cope with the ever-growing flow of wireless data traffic, using limited spectral resources. As such, spectrum sharing, which allows different grades of users, as well as multiple networking standards to co-exist and utilize in the same frequency band, has become a topic of great intrigue. Due to the inherent advantages of these schemes, the US government has opened up vast amounts of federal spectrum that supports spectrum sharing. The Citizens Broadband Radio Service (CBRS) proposed by the Federal Communications Commission (FCC) is one of them. A tiered …

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 …

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 …

Numerical Simulation Of Vibration - Based Piezoelectric Energy Harvester For Shape Comparison, Adriana Rosas

Theses and Dissertations

This work investigates the shape optimization of piezoelectric energy harvesters subjected to mechanical vibration using ABAQUS/Standard software. Three piezoelectric energy harvesters with different dimensions but the same areas were created to identify if model dimensions have an impact on the output voltage. The models were tested at different speeds to create an output voltage. Once the output voltages were obtained, the results were compared with each other to find if shape optimization on piezoelectric energy harvesters has an impact on scavenging energy from mechanical vibrations.