Engineering Commons^™

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 …

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 …

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 …

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 …

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.

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 …

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 …

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 …

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 …

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.

Water Hardness Removal By Electrochemical Precipitation In A Continuous Flow Condition Using Conductive Concrete As Cathode, Tahsin Tareque

Theses and Dissertations

This study focuses on the electrochemical precipitation (EP) process to reduce excess water hardness from the Lower Rio Grande Valley (LRGV) tap water using electrically conductive concrete as cathode in a continuous flow condition. LRGV tap water is extremely hard with hardness more than 350 mg/L as CaCO3. Humans can pleasantly consume water with hardness less than 150 mg/l as CaCO3 according to World Health Organization (WHO). Hard water is also known to cause mechanical problems to boilers and heat exchangers. In this process, electricity is passed through electrodes submerged in electrolyte, which causes an alkaline environment around the cathode …

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 …

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 …

Simncore: Multilevel Cache Memory Design Simulator For Manycore System, Provashish Roy

Theses and Dissertations

The current trend in a processor design has moved from multicore to manycore (tens to hundreds, or more cores) to support more computational power based on parallelism. One of challenges is how to handle such large number of cores’ data in cache memories through an efficient inter-core communication and cache coherence. To meet the demand, this paper presents a manycore cache memory simulator for research and education purposes. The proposed simulator, called as SIMNCORE, is to design and evaluate various multi-level, such as L1 and L2, cache memories for manycore processing. The SIMNCORE will implement various trace files collected from …

Enhancing Human Schwann Cells Reparative Behavior Using Heparin/Collagen Layer-By-Layer Coatings, Luis Carlos Pinzon-Herrera

Graduate Theses and Dissertations

When a peripheral nerve injury (PNI) occurs, the gold standard for tissue regeneration is the use of autografts. However, due to the secondary effects produced by multiple surgeries involved in the removal and implantation of autografts for very small lesions, it is possible to replace them with the use of Nerve Guide Conduits (NGCs). However, NGCs are limited to short lesions (less than 1 cm). This limitation is caused by the absence of compounds in the extracellular matrix (ECM) that autografts can provide. Since much of the regenerative process takes place on the NGC surface, our work aims to modify …

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 …

Recycling Of Cured Carbon Fiber/Epoxy Resin Laminated Composites Scraps: Processing And Characterization, Khaled Mohammed Al Harmoodi

Theses

The concept of reinforced composites came decades ago from the need to fabricate high-strength, heat-resistant, wear-resistant, and low-density materials. The polymer matrix composites offer a wide range of applications due to the collaborative nature of the functional fillers and polymers present. Towards the twenty-first century, the aviation industry flourished due to flying being the preferred way of travel across states and countries. With such a massive demand for air transport, there is an equally parallel demand for the production of aircraft components. This study aims to reuse the waste of uncured composite prepreg scraps from the ply-cutting manufacturing process in …

Synthesis And Characterization Of Vo2 Thin Films On Piezoelectric Substrates, Samee Azad

All Theses

Polycrystalline VO₂ thin films synthesized on two piezoelectric substrates (AT-cut quartz and GaN/AlGaN/GaN/Si) using low pressure direct oxidation technique have been characterized and compared to VO₂ grown on traditional non-piezoelectric substrates sapphire and SiO₂/Si. X-ray diffraction and atomic force microscopy characterization performed on the as grown films confirmed high quality of the VO₂ films grown on both the piezoelectric and non-piezoelectric substrates. Changes in material properties associated with the semiconductor metal transition (SMT) of the VO₂ films were investigated through resistivity and transmitted optical power changes measured across the SMT. It was observed that …

Supporting Us Army Next-Generation Ground Vehicle Simulation Modeling Using An Integrated Ontology Suite, Edward Louis

All Theses

The development of the US Army’s next-generation of ground vehicle systems is supported by simulations that predict vehicle performance and inform engineering design choices in the design and acquisition process. In this paper, we describe the development of an Integrated Ontology Suite to support modeling and simulation of next generation military ground vehicles. The ontology suite is intended to address model reuse challenges and increase the shared understanding of ground vehicle system simulations. It is intended to function in a Model Library structure that stores, documents, assembles, and executes vehicle simulations. The ontology suite consists of four domain ontologies: Vehicle …

Effects Of Polymer Side-Group Size On Interfacial Mechanics Of Graphene-Polymer Nanocomposites, Grace Brokaw

All Theses

Graphene-reinforced polymer nanocomposites possess excellent mechanical, thermal, and electrical properties, which make them promising candidates for various applications. Favorable interfacial interactions and mechanics between graphene sheets and polymer matrices are often essential to achieve superior mechanical properties. Nevertheless, it remains largely elusive how molecular features of polymer systems, particularly the side-group size of polymer chains, affect the interfacial mechanics between graphene sheets and polymer matrices, primarily due to challenges in well controlling these features in experiments. On the other hand, exploring their roles in the mechanical properties of graphene-polymer nanocomposites is very expensive to study with all-atomistic molecular dynamics (MD) …

Flexural Testing Of Precast Reinforced Concrete Bridge Slabs, Evaluation Of Deterioration And Strengthening Applications, Alyssa Leaman

All Theses

This thesis investigates the strength of flat precast concrete slabs that were taken from decommissioned South Carolina bridges. The specimens tested spanned 14 ft (4.3 m) or 15 ft (4.6 m), were 5 ft (1.5 m) or 5.5 ft (1.7 m) wide, and 8.25 in (210 mm) thick. In South Carolina, there are approximately 3000 similar bridges that use these slab members. Testing was conducted to determine the flexural capacity of “typical” slabs and the residual strength of slabs having visible deterioration of both the rebar and the concrete. For the slabs that were load rated below the new standards, …

Utilizing Systematic Design And Shape Memory Alloys To Enhance Actuation Of Modular High-Frequency Origami Robots, Jessica M. Den Haese

All Theses

Shape memory alloys (SMAs) describe a group of smart metallic materials that can be deformed by external magnetic, thermal, or mechanical influence and then returned to a predetermined shape through the cycling of temperature or stress. They have several advantages, such as having excellent mechanical properties, being low cost, and being easily manufactured, while also providing a compact size, completely silent operation, high work density, and requiring less maintenance over time. SMAs can undergo sold-to-solid phase transformations, and it is because of these phase transformations that they can experience shape memory effect (SME); or the ability to recover from a …

Flexural Bond Strength Of Masonry Assemblies With Lightweight Grout, Benjamin L. Hiner

All Theses

Lightweight grout has many potential benefits in masonry construction, including minimizing mass, improving thermal performance, and potentially reducing shrinkage cracking via internal curing. However, insufficient testing of masonry assemblies with lightweight grout has been conducted to suggest appropriate design modification factors akin to the lambda factor in ACI 318-19. The objective of this paper is to study the tensile bond behavior of masonry assemblies grouted with lightweight grout and to suggest appropriate equations for predicting design capacity. A moment couple test is designed specifically for grouted masonry assemblies and has additional capacity compared to the traditional ASTM 1072 bond wrench …

Transforming Character Faces Based On Perceived Personality Traits, Kara Porter

All Theses

The ability to read other human's faces is a crucial part of everyday life. Subconsciously, the human brain analyzes someone's face within the first few seconds of seeing it, making a variety of conclusions ~\cite{FacePerp} such as gathering information about emotional state and assuming character traits this person might possess. The purpose of this thesis is to create a tool that allows a user to alter features of a character's three dimensional (3D) face mesh to look increasingly or decreasingly like the character possesses certain personality traits. Using a sample set of randomly generated faces, a survey is conducted to …

Oam-Based Wavelets In A High Speed Optical Probing System For Measuring The Angular Decomposition Of The Environment, Justin Free

All Theses

This thesis presents the theoretical development of orbital angular momentum (OAM) based wavelets for the analysis of localized OAM information in space. An optical probing system for generating and detecting these wavelets is demonstrated; individual wavelets can scan the environment in 10µs or less. The probing system was applied to a three-dimensional atmospheric turbulence distribution to obtain a continuous wavelet transform of the angular information of the turbulent propagation path about a fixed radius. An entire continuous wavelet transform was measured in 3.8ms; the measurements are much faster than the turbulence and give insight into the short time scale of …

An Application Of Optimized Bistable Laminates As A Low Velocity, Low Impact Mechanical Deterrent, Graham Lancaster

All Theses

This research considers the problem of using bistable laminates as a mechanical deterrent to the impending impact of a particle. The structure will be controlled through an algorithm that will utilize piezoelectric devices to activate them in unison with the bistable laminate to successfully deter. A novel experimental setup will be constructed to ensure that the bistable laminate stays fixed when acting as a mechanical deterrent. Piezoelectricity is the main driving force of the bistable laminate to morph and this study will use a Macro Fiber Composite (MFC) actuator that contains piezoelectric ceramic rods in a patch to transfer electrical …

Mango Surface Color Features Measurement Using Digital Image Processing, Md Towfiqur Rahman, Goutom Kumar, Md Abdul Momin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Summary

Postharvest processing of agricultural produce is still done the conventional way in Bangladesh. Manual grading of agricultural produce, especially fruits and vegetables, is laborious and costly due to acute shortage of labor during the peak season, as well as difficulty maintaining the product quality. Machine vision system (MVS) applications are widely used nowadays as a non-destructive and cost-effective technology for automatically grading and sorting large volumes of produce in the packing house according to size, shape, color, texture, and surface defects. In this study, a simple MVS was constructed measuring different color features of mango fruit surface as a …

Framework For The Use Of Extended Reality Modalities In Aec Education, Barbara Oliveira Spitzer, Jae Hoon Ma, Ece Erdogmus, Ben Kreimer, Erica Ryherd, Heidi Diefes-Dux

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The educational applications of extended reality (XR) modalities, including virtual reality (VR), augmented reality (AR), and mixed reality (MR), have increased significantly over the last ten years. Many educators within the Architecture, Engineering, and Construction (AEC) related degree programs see student benefits that could be derived from bringing these modalities into classrooms, which include but are not limited to: a better understanding of each of the subdisciplines and the coordination necessary between them, visualizing oneself as a professional in AEC, and visualization of difficult concepts to increase engagement, self-efficacy, and learning. These benefits, in turn, help recruitment and retention efforts …

High Throughput And Highly Controllable Methods For In Vitro Intracellular Delivery, Justin Brooks, Grayson Minnick, Prithvijit Mukherjee, Arian Jaberi, Lingqian Chang, Horacio D. Espinosa, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

In vitro and ex vivo intracellular delivery methods hold the key for releasing the full potential of tissue engineering, drug development, and many other applications. In recent years, there has been significant progress in the design and implementation of intracellular delivery systems capable of delivery at the same scale as viral transfection and bulk electroporation but offering fewer adverse outcomes. This review strives to examine a variety of methods for in vitro and ex vivo intracellular delivery such as flow-through microfluidics, engineered substrates, and automated probe-based systems from the perspective of throughput and control. Special attention is paid to a …