Materials Science and Engineering Commons^™

The Limits & Effects Of Draw On Properties And Morphology Of Pan-Based Precursor And The Resultant Carbon Fibers, Sarah Edrington

Theses and Dissertations--Mechanical and Aerospace Engineering

The process, structure, and property relationship of PAN fiber as a precursor to carbon fiber was studied. The limitations of stable spinning and property improvement associated with hot draw in solution spinning were found and quantified. Conditions were varied to generated precursor fiber up to the limit of draw, from which actual samples were collected for thermal conversion to carbon fiber. Samples of PAN and subsequent carbon fiber were characterized using tensile testing and x-ray analysis. The effects of draw on modulus and break stress, as well as the orientation of the crystalline structure of both parent precursor and resultant …

Shape Memory Behavior Of Dense And Porous Niti Alloys Fabricated By Selective Laser Melting, Soheil Saedi

Theses and Dissertations--Mechanical and Aerospace Engineering

Selective Laser Melting (SLM) of Additive Manufacturing is an attractive fabrication method that employs CAD data to selectively melt the metal powder layer by layer via a laser beam and produce a 3D part. This method not only opens a new window in overcoming traditional NiTi fabrication problems but also for producing porous or complex shaped structures. The combination of SLM fabrication advantages with the unique properties of NiTi alloys, such as shape memory effect, superelasticity, high ductility, work output, corrosion, biocompatibility, etc. makes SLM NiTi alloys extremely promising for numerous applications.

The SLM process parameters such as laser power, …

Effects Of Temperature, Orientation, Load Level And Indenter Shape On The Indentation Response Of Niti-Based Shape Memory Alloys, Peizhen Li

Theses and Dissertations--Mechanical and Aerospace Engineering

Owing the capability of recovering large deformations through reversible phase transformation, shape memory alloys (SMAs) are well-known for their unique behaviors such as shape memory effect (SME) and superelasticity (SE), which can also be characterized by instrumented indentation techniques. Nickel titanium (NiTi) SMAs have been extensively used for nano/micro-indentation studies and widely applied to biomedical and other elaborate medical devices.

In this study, indentation responses of NiTi, NiTiHf, NiTiHfPd and NiTiHfCu alloys were investigated using spherical and Berkovich indenters at room temperature. Spherical and Berkovich indentation hardness, modulus, and work/depth recoverable ratio of these NiTi-based alloys were revealed as a …

Study Of Surface Passivation Behavior Of Crystalline Silicon Solar Cells, Haider Ali

Electronic Theses and Dissertations

To achieve efficiencies approaching the theoretical limit of 29.4% for industrially manufactured solar cells based on crystalline silicon, it is essential to have very low surface recombination velocities at both the front and rear surfaces of the silicon substrate. Typically, the substrate surfaces feature contacted and uncontacted regions, and recombination should be limited for both to maximize the energy conversion efficiency. Uncontacted silicon surfaces are often passivated by the deposition of silicon nitride (SiNx) or an aluminum oxide film with SiNx as capping layer (Al2O3/SiNx stack). Further, proper surface preparation and cleaning of Si wafers prior to deposition also plays …

Interaction Between Carbon Nanotubes And Metals (Al, Cu) And The Effects On Resultant Properties Of The Hybrid Materials, Jingyin Jiang

Electronic Theses and Dissertations

Due to the exceptional strength, stiffness and excellent electrical and thermal properties, carbon nanotubes (CNTs) have been regarded as promising candidates for advanced nanoelectronics and multifunctional nanocomposites. In this dissertation, the interaction of CNTs with metals have been investigated and the resultant electrical conduction have been analyzed, aiming to develop innovative avenues to best utilize CNTs' potential. In order to do so, quantum mechanics calculations have been carried out to study that how to obtain greater electrical conduction by doping metals (Cu, Al) which tailor the electronic structure of three different types of metal-CNT interactions, : 1) encapsulation of atoms …

Printable Carbon Nanotube Based Multifunctional Nanocomposites For Strain Sensing And Self-Heating, Xin Wang

Electronic Theses and Dissertations

The unique properties of carbon nanotubes (CNTs) represent a potential for developing a piezo-resistive strain sensor and a resistive heating sheet with a smart structure. Conventional fabrication techniques of CNT based nanocomposites such as molding, casting or spray coating lack the ability to control the geometry and properties of fabricated composites. In order to meet the various requirements of strain sensing or self-heating applications, nanocomposites with complex geometry and controllable properties are in high demand. Digital printing technique is able to fabricate CNT films with precisely controlled geometry with the help of computer aided design, and their properties could also …

Structural Characteristics And Corrosion Behavior Of Bio-Degradable Zn-Li Alloys In Stent Application, Shan Zhao

Dissertations, Master's Theses and Master's Reports

Zinc has begun to be studied as a bio-degradable material in recent years due to its excellent corrosion rate and optimal biocompatibility. Unfortunately, pure Zn’s intrinsic ultimate tensile strength (UTS; below 120 MPa) is lower than the benchmark (about 300 MPa) for cardiovascular stent materials, raising concerns about sufficient strength to support the blood vessel. Thus, modifying pure Zn to improve its mechanical properties is an important research topic.

In this dissertation project, a new Zn-Li alloy has been developed to retain the outstanding corrosion behavior from Zn while improving the mechanical characteristics and uniform biodegradation once it is implanted …

Magnetic Behavior Of Bulk And Nanostructured Mnxtas2, Lucas Paul Beving

Honors Program Theses

At its base, material science research aims to categorize specific materials by their various attributes, such as structure, integrity, electronic properties, magnetic properties, and others. By categorizing materials in this way, it becomes easier to generalize the application of a specific material to those within a broader category. The interest in materials that exhibit useful characteristics at small scales derives directly from the technology industry’s need for smaller and smaller devices. Two-dimensional materials are of great interest for this reason.

Two-dimensional materials are comprised of many single layers, or planes, stacked together to create a crystal. Each layer may be …

Impact Of Trucking Network Flow On Preferred Biorefinery Locations In The Southern United States, Timothy M. Young, Lee D. Han, James H. Perdue, Stephanie R. Hargrove, Frank M. Guess, Xia Huang, Chung-Hao Chen

Electrical & Computer Engineering Faculty Publications

The impact of the trucking transportation network flow was modeled for the southern United States. The study addresses a gap in existing research by applying a Bayesian logistic regression and Geographic Information System (GIS) geospatial analysis to predict biorefinery site locations. A one-way trucking cost assuming a 128.8 km (80-mile) haul distance was estimated by the Biomass Site Assessment model. The "median family income," "timberland annual growth-to-removal ratio," and "transportation delays" were significant in determining mill location. Transportation delays that directly impacted the costs of trucking are presented. A logistic model with Bayesian inference was used to identify preferred site …

Utilizing Reprap Style 3d Printers For The Manufacturing Of Composite Heat Exchangers, John Laureto

Dissertations, Master's Theses and Master's Reports

The low cost 3D printing market is currently dominated by the application of RepRap (self-replicating rapid-prototyper) variants. Presented in this document are practical utilizations of RepRap technology. Developed are innovative processes to manufacture composite materials systems for thermal management solutions.

First, a laser polymer welder system is validated by quantifying maximum peak load and weld width of linear low density polyethylene (LLDPE) lap welds as a function of linear energy density. The development of practical engineering data, in this application, is critical to producing mechanically durable welds. Developed laser and printer parameter sets allow for manufacturing of LLDPE multi-layered heat …

Evaluation Of Thermal Stability Of Ausferrite In Austempered Ductile Iron Using Differential Scanning Calorimetry, Karl Warsinski

Dissertations, Master's Theses and Master's Reports

Austempered Ductile Iron (ADI) is prone to changes in microstructure and mechanical properties when exposed to elevated service temperatures. Differential Scanning Calorimetry has been used to evaluate the stabilizing effects of copper, nickel, molybdenum, and cobalt on the ausferrite structure. Previous studies have conflated the effects of various alloy additions, and little effort has been made to systematically catalog the effects of individual elements. The focus of the current research has been to identify alloying elements that more strongly stabilize the ausferrite structure in order to improve service life of ADI at elevated temperatures. Nickel has been shown to have …

Molecular Modeling Of Aerospace Polymer Matrices Including Carbon Nanotube-Enhanced Epoxy, Matthew Radue

Dissertations, Master's Theses and Master's Reports

Carbon fiber (CF) composites are increasingly replacing metals used in major structural parts of aircraft, spacecraft, and automobiles. The current limitations of carbon fiber composites are addressed through computational material design by modeling the salient aerospace matrix materials. Molecular Dynamics (MD) models of epoxies with and without carbon nanotube (CNT) reinforcement and models of pure bismaleimides (BMIs) were developed to elucidate structure-property relationships for improved selection and tailoring of matrices.

The influence of monomer functionality on the mechanical properties of epoxies is studied using the Reax Force Field (ReaxFF). From deformation simulations, the Young’s modulus, yield point, and Poisson’s ratio …

Multiscale Modeling: Thermal Conductivity Of Graphene/Cycloaliphatic Epoxy Composites, Sorayot Chinkanjanarot

Dissertations, Master's Theses and Master's Reports

The thermal property of epoxy as the binder in the Carbon Fiber (CF) composites, especially thermal conductivity is important to achieve the advance technology and to improve the performance of materials. Multiscale modeling including molecular dynamic (MD) modeling and micromechanical modeling is used to study the properties of neat Cycloaliphatic Epoxies (CE) and Graphene nanoplatelet (GNP)/CE with and without covalent functionalization.

The thermal properties (glass-transition temperature, thermal expansion coefficient, and thermal conductivity) and mechanical properties of CE system are investigated by MD modeling using OPLS-All Atom force field. A unique crosslinking technique is developed to achieve the cured CE models …

Polyvinyl Alcohol (Pva) Fiber-Reinforced Rubber Concrete And Rubberized Self-Compacting Concrete, Jiaqing Wang

Dissertations, Master's Theses and Master's Reports

This study experimentally investigates the mechanical performance and durability of Polyvinyl Alcohol (PVA) fiber-reinforced rubber concrete and the rubberized self-compacting concrete. The waste rubber particles were introduced as a partial replacement of fine aggregate in the plain concrete. In addition, the waste tire rubbers were pre-treated with alkali surface treatment method to enhance the performance. The PVA fibers were added to the concrete mixes to enhance the post-failure resistance and thus fracture energy. Rubberized fiber concrete samples were prepared with different fine aggregate replacement ratios and the optimum fiber content. At the same time, the rubber particles had been used …

Microstructural Evolution And Mechanical Properties Of Zn-Ti Alloys For Biodegradable Stent Applications, Zhiyong Yin

Dissertations, Master's Theses and Master's Reports

Stents made of biodegradable metallic materials are increasingly gaining interest within the biomaterials field because of their superior mechanical properties and biodegradation rates as compared to polymeric materials. Zinc and its alloys have been developed and investigated as possible candidates for biodegradable stent applications in the last five years. This study intended to formulate and characterize a new series of Zn-Ti alloys, with titanium additions of less than 1-3 wt%, with the primary objective to develop and select an alloy that meets benchmark values of mechanical properties for biodegradable stents. A series of Zn-Ti alloys was formulated through vacuum induction …

Formulation And Testing Of Biodegradable Polymeric Coating On Zinc Wires In Cardiovascular Stent Application, Avishan Arab Shomali

Dissertations, Master's Theses and Master's Reports

Biodegradable and biocompatible poly (L-lactic-acid) (PLLA) coating was applied on a modified zinc (Zn) substrate by dip coating, with the intent to delay the bio-corrosion and slow the degradation rate of zinc substrate. 3-(Trimethoxysilyl) propyl methacrylate (MPS) was used for modification of the zinc substrate for promoting the adhesion between the metallic substrate and the polymer coating. It is hypothesized that the delay in Zn biodegradation could be useful in the first several weeks to prevent the early loss of mechanical integrity of the endovascular stent and to improve the healing process of the diseased vascular site. The PLLA coating …

Rubber Additives To Concrete Specimens, Kendall J. Sweitzer, Mary Mccannon

Williams Honors College, Honors Research Projects

Rubber, as an additive to concrete, would hypothetically cause a concrete specimen to take on some mechanical characteristics of the rubber to a certain degree. In particular, the concrete’s durability should increase when exposed to fluctuating temperature conditions due to the rubber additive. This experiment sets out to test crumb rubber as a concrete additive, cured under various atmospheric conditions. The effects shall be measured via a simple concrete compression test.

Unfortunately, several errors took place during experimental process that led to inconclusive results. However, it can be reasonably considered from testing Matrix One that the addition of crumb rubber …

Design Of Natural Rubber Extraction From Tks Dandelion, Jehad S. Alrawajfeh, Trevor Cody, Jason Pogozelski

Williams Honors College, Honors Research Projects

A design was developed for a controlled environment agriculture 3D greenhouse to grow and harvest TKS dandelions, as well as a processing plant to extract natural rubber and inulin from the roots. The design capacity was scaled for both pilot- and full-scale production: 100 and 100,000 tonnes of natural rubber per year, respectively. The byproducts of the process were dandelion greens, inulin, cellulose, and glucose; all of these except for cellulose were able to be valorized. The greenhouse was designed based on existing 3D hydroponic growing environments, and the extraction process was designed based on the original TKS dandelion extraction …

Pitting Corrosion Of 410 Stainless Steel In Hcl Solutions, Paul D. Krell

Williams Honors College, Honors Research Projects

410 stainless steel (SS) is a material used in HCl services, such as distillation column trays in oil refineries. Unlike other alloys, however, the oil refining industry lacks a good reference for the corrosion rate of 410 SS at the varying HCl concentrations and temperatures the material might experience as trays in crude unit distillation columns. The goal of this project is to fill that knowledge gap. The corrosion behavior of 410 SS in HCl environments of pH 0.50, 1.25, 2.25, 3.25, and 4.25 at temperatures of 38, 52, 79, and 93°C was investigated using several methods. Cyclic potentiodynamic polarization …

Design And Testing Of Flexible Lithium-Ion Batteries, Ryan C. Kramanak, Matt A. Murrow, Matt Stolfer, Jered Tyler, Aaron Moser

Williams Honors College, Honors Research Projects

The goal of this disquisition is to delineate the development of a material and casing suitable for flexible lithium-ion rechargeable batteries. Development of these cells is driven by increasing interest in portable and flexible electronics. The goal is to implement them into items such as smart cards, wearable electronics, novelty packages, flexible displays, and transdermal drug delivery patches. To accomplish this task, a number of individual cathode compounds were explored that used different compositions of lithium cobalt oxide and other compounds. These cells were tested in a generic and easily manufacturable cell casing. After the catholyte compound testing was completed …

Experimental And Computational Investigation Of Multi-Principal Element Alloys, Mohsen Beyramali Kivy

Doctoral Dissertations

"Multi-principal element (MPE) alloys, unlike traditional alloys, consist of five or more principal elements with near equi-atomic compositions creating a large new compositional space for exploring new alloy possibilities. However, designing MPE alloys with the desired phases, microstructures and properties is challenging task, and there is a demand for basic research for a better understanding of structure-processing-property relations in these alloys.

In this Ph.D. research, different computational models and experiments were integrated to study phase formations, and mechanical properties of different MPE alloys. Density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations were used to determine crystal structures, …

Dirac Surface States Of Magnetic Topological Insulators, Seng Huat Lee

Doctoral Dissertations

"Magnetic topological insulator (TI) has been theoretically proposed to be a platform for inducing magnetic monopole and exhibit fascinating quantum phenomena, whereas topological superconductor can host Majorana fermions, particles that are their own antiparticles, which can be manipulated for topological quantum computing. In this dissertation, we experimentally demonstrated that by intercalation of different transition metals in the van der Waals gaps of Bi₂Se₃ TI, magnetism and even superconductivity can be induced. In Fe_xBi₂Se₃, antiferromagnetism is induced with a transition temperature at ~ 100 K. Coexistence of the Dirac surface state with …

Pore Formation In Aluminum Castings: Theoretical Calculations And The Extrinsic Effect Of Entrained Surface Oxide Films, Pedram Yousefian

UNF Graduate Theses and Dissertations

Aluminum alloy castings are being integrated increasingly into automotive and aerospace assemblies due to their extraordinary properties, especially high strength-to-density ratio. To produce high quality castings, it is necessary to understand the mechanisms of the formation of defects, specifically pores and inclusion, in aluminum. There have been numerous studies on pore formation during solidification which lead to hot tearing and/or reduction in mechanical properties. However, a comprehensive study that correlates pore formation theory with in situ observations and modeling assumptions from the literature as well as experimental observations in not available. The present study is motivated to fill this gap. …

Synthesis, Characterization, And Enhanced Magnetic Properties Of Iron Carbide Nanomaterials, Brent M. Williams

Theses and Dissertations

Permanent magnets are classified as hard magnetic materials with the main purpose of generating flux for applications such as electric motors, turbines, and hard drives. High coercivity, magnetic remanence, and saturation values with high stability are some of the requirements for permanent magnets. Rare-earth magnets including neodymium and samarium based magnets are known to have superior magnetic properties due to their high magnetocrystalline anisotropy. However, due to the price of rare-earth materials development of alternate permanent magnets composed of inexpensive materials is an ongoing process. Previously cobalt carbide (Co_xC) have shown promise as a potential rare-earth free magnet …

Signal-To-Noise Ratio Enhancement Using Graphene-Based Passive Microelectrode Arrays, Sepideh Rastegar, Justin Stadlbauer, Kiyo Fujimoto, Kari Mclaughlin, David Estrada, Kurtis D. Cantley

Materials Science and Engineering Faculty Publications and Presentations

This work is aimed toward the goal of investigating the influence of different materials on the signal-to-noise ratio (SNR) of passive neural microelectrode arrays (MEAs). Noise reduction is one factor that can substantially improve neural interface performance. The MEAs are fabricated using gold, indium tin oxide (ITO), and chemical vapor deposited (CVD) graphene. 3D-printed Nylon reservoirs are then adhered to the glass substrates with identical MEA patterns. Reservoirs are filled equally with a fluid that is commonly used for neuronal cell culture. Signal is applied to glass micropipettes immersed in the solution, and response is measured on an oscilloscope from …

Application Of Artificial Neural Networks To Identify Equilibration In Computer Simulations, Michael H. Leibowitz, Evan D. Miller, Michael M. Henry, Eric Jankowski

Materials Science and Engineering Faculty Publications and Presentations

Determining which microstates generated by a thermodynamic simulation are representative of the ensemble for which sampling is desired is a ubiquitous, underspecified problem. Artificial neural networks are one type of machine learning algorithm that can provide a reproducible way to apply pattern recognition heuristics to underspecified problems. Here we use the open-source TensorFlow machine learning library and apply it to the problem of identifying which hypothetical observation sequences from a computer simulation are "equilibrated" and which are not. We generate training populations and test populations of observation sequences with embedded linear and exponential correlations. We train a two-neuron artificial network …

การเพิ่มการกักเก็บของแคลเซียมคาร์บอเนตชนิดตกตะกอนและนาโนแคลเซียมคาร์บอเนตในกระดาษโดยใช้พอลิอะคริเลตและพอลิอะคริลาไมด์, มนต์นภา ลัภนพรวงศ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้มุ่งศึกษาถึงผลจากการเติมแคตไอออนิกพอลิอะคริลาไมด์เป็นสารเพิ่มการตกค้างและโซเดียมพอลิอะคริเลตเป็นสารช่วยกระจายตัว เพื่อเพิ่มปริมาณการกักเก็บตัวเติม 2 ชนิด ได้แก่ แคลเซียมคาร์บอเนตชนิดตกตะกอนและนาโนแคลเซียมคาร์บอเนตภายในเนื้อกระดาษ โดยใช้เยื่อเคมีฟอกทางการค้าในอัตราส่วนเยื่อใยสั้นและเยื่อใยยาวเท่ากับ 70:30 ของน้ำหนักแผ่นทดสอบ นำไปบดเยื่อเพื่อให้มีค่าสภาพการระบายน้ำ 325 ± 25 mL CSF จากนั้นศึกษาถึงปริมาณการเติมแคตไอออนิกพอลิอะคริลาไมด์และโซเดียมพอลิอะคริเลตที่เหมาะสมสำหรับตัวเติมแคลเซียมคาร์บอเนตทั้งสองชนิด เพื่อให้มีปริมาณการกักเก็บภายในเนื้อกระดาษที่ร้อยละ 30 ของน้ำหนักแผ่นทดสอบ โดยพบว่าเมื่อเติมแคตไอออนิกพอลิอะคริลาไมด์ที่ร้อยละ 1.1 ของน้ำหนักเยื่อแห้งส่งผลให้มีปริมาณการกักเก็บสูงสุด แต่อย่างไรก็ตามพบว่าการเติมโซเดียมพอลิอะคริเลตในสารแขวนลอยแคลเซียมคาร์บอเนต ทำให้ปริมาณการกักเก็บตัวเติมภายในกระดาษลดลง โดยเฉพาะในภาวะที่เติมนาโนแคลเซียมคาร์บอเนตเนื่องจากมีการกระจายตัวของอนุภาคที่มากเกินไป ส่งผลให้อนุภาคเล็ก ๆ ลอดไปกับน้ำผ่านรูตะแกรงระหว่างทำการขึ้นแผ่น เมื่อได้ปริมาณที่เหมาะสมในการเติมสารเติมแต่งแล้วนั้นจึงได้ศึกษาถึงการใช้ร่วมกันระหว่างแคลเซียมคาร์บอเนตชนิดตกตะกอนและนาโนแคลเซียมคาร์บอเนตในสัดส่วนที่ต่างกัน ตั้งแต่ 100: 0 75:25 50:50 25:75 ถึง 0:100 ในการปรับปรุงสมบัติกระดาษโดยเทียบกับภาวะที่ไม่เติมสารเติมแต่งใด ๆ พบว่าแม้ว่าแคลเซียมคาร์บอเนตชนิดตกตะกอนและนาโนแคลเซียมคาร์บอเนตจะให้สภาพพิมพ์ได้และสมบัติทางทัศนศาสตร์ใกล้เคียงกัน แต่เมื่อสัดส่วนของนาโนแคลเซียมคาร์บอเนตเพิ่มขึ้นกลับทำให้ความเรียบของผิวกระดาษและความหนาแน่นของแผ่นทดสอบลดลง นอกจากนี้เมื่อนำไปทดสอบความแข็งแรงต่อแรงดึงและแรงฉีกพบว่าเกิดการฟุ้งกระจายของอนุภาคแคลเซียมคาร์บอเนตมากขึ้นเมื่อแผ่นทดสอบฉีกขาด

Fabrication Of Flexible, Biofunctional Architectures From Silk Proteins, Ramendra K. Pal

Theses and Dissertations

Advances in the biomedical field require functional materials and processes that can lead to devices that are biocompatible, and biodegradable while maintaining high performance and mechanical conformability. In this context, a current shift in focus is towards natural polymers as not only the structural but also functional components of such devices. This poses material-specific functionalization and fabrication related questions in the design and fabrication of such systems. Silk protein biopolymers from the silkworm show tremendous promise in this regard due to intrinsic properties: mechanical performance, optical transparency, biocompatibility, biodegradability, processability, and the ability to entrap and stabilize biomolecules. The unique …

Tightening The Loop On The Circular Economy: Distributed Plastic Recycling With An Open Source Recyclebot, Shan Zhong

Dissertations, Master's Theses and Master's Reports

Following the goals of a circular economy, the growth of both plastic consumption and prosumer 3-D printing are driving an interest in producing 3-D printer filament from waste plastic. However, traditional recycling can have a significant environmental impact as it demands the collection and transportation of relatively low-density waste plastics to collection centers and reclamation facilities for separation and reconstruction. Compared to the traditional recycling, distributed recycling (where consumers directly recycle their own waste) has the potential to reduce energy consumption because it can save the energy for transportation needed in conventional recycling. A promising method of such distributed plastic …

Mse Annual Report 2017, Department Of Materials Science And Engineering, Michigan Technological University

Department of Materials Science and Engineering Annual Reports

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