Materials Science and Engineering Commons^™

Interfacial Corrosion Of Copper And The Formation Of Copper Hydroxychloride, Mary Teague, Shengxi Li, Hongbo Cong

Williams Honors College, Honors Research Projects

Electrical circuitry is an industry, among many others, heavily using the element of copper. Ensuring the mechanical integrity of Cu is crucial, especially in salt environments, for the multifaceted composition of circuits. 4N NaCl solution (equilibrium concentration in ~84% RH) simulated this three-phase system. Rectangular Cu samples were partially immersed in both ambient and continuous lab air sparging atmospheres to understand waterline corrosion of the metal. Open circuit potentials (OCP) were continuously taken during the immersion testing for a maximum of 5 days. A scanning electron microscopy (SEM) equipped with an energy dispersive X-ray spectrometer (EDS), Raman spectroscopy, and 3-D …

Investigation Of Scanning Kelvin Probe Techniques, Nicholas D'Angelo Jr., Hongbo Cong

Williams Honors College, Honors Research Projects

The original scope of this work was to advance the understanding of corrosion properties of additively manufactured (AM) materials by correlating microstructural defects in AM materials to the material conventional counterparts utilizing a scanning kelvin probe [Ametek VeraSCAN Electrochemical System]. However, upon the initiation of project research, it was observed that the system was not operational due to unknown hardware and software problems. The evolved scope of this work was to reconcile the operational issues and develop a repair and mitigation plan. After extensive troubleshooting, it was determined that the software was not properly configured, and the electrometer had permanently …

Design Of Shape-Conforming Nosecone For Optimal Fluid Flow From Transonic To Supersonic Range, Anna Tombazzi

Williams Honors College, Honors Research Projects

Modern flight vehicles, such as rockets, missiles, and airplanes, experience a force caused by forebody wave drag during the flight. This drag force is induced when the frontal point of each vehicle breaks the pressure wave during flight. Efforts to reduce this wave drag force to improve flight efficiency include modifying the nosecone profile of the flight vehicles to lower the drag force.

This project revolved around creating a design to make the transformation of nosecone shapes from a ¾ Parabolic profile to a ½ Power Series profile possible, mid-flight. Using a novel nosecone assembly, shape memory alloys (SMAs) and …

Galvanic And Pitting Corrosion Of A Fastener Assembly, Julie Shallman

Williams Honors College, Honors Research Projects

This research focuses on coupled galvanic/pitting corrosion of AA7075 when combined with stainless steel in a fastener assembly. A one-dimensional mathematical model of a well-mixed thin film electrolyte is developed to predict the damage profile of the AA7075 surface when its protective coating is damaged. The damage exposes the galvanic couple. A time dependent system of partial differential equations for potential, chloride concentration, aluminum ion concentration, and damage is developed and solved numerically. Two approaches to calculate the current density within aluminum pits are discussed. The first is a current balance between the cathodic, anodic and passive portions of the …

Improving The Relative Calculations Of Volta Potential Differences Acquired From Scanning Kelvin Probe Force Microscopy (Skpfm) From Comparing An Inert Material To First-Principle Calculations, C. M. Efaw, T. Da Silva, P. H. Davis, L. Li, E. Graugnard, M. Hurley

Materials Science and Engineering Faculty Publications and Presentations

An improved relative scaling of Volta potential differences (VPD) acquired from scanning Kelvin probe force microscopy (SKPFM) was developed by quantifying the probe work function. In corrosion studies, SKPFM has been used to identify local nobility of complex metallic systems and provide theoretical corrosion initiation sites. However, large variability in measured VPD values for metallic phases has led to controversy in their interpretation. Tracking changes of the probe work function has been shown to decrease the variability seen in SKPFM results. To quantify the work function of SKPFM probes, the measured VPD of an inert gold standard was compared to …

อิทธิพลของเถ้าหนักลิกไนต์ต่อการแอ่นตัวของกระเบื้องเซรามิกสโตนแวร์, ธฤต ประสาทเสรี

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ได้ทำการศึกษาผลของการใช้เถ้าหนักลิกไนต์เป็นส่วนผสมในเนื้อกระเบื้องเซรามิกสโตนแวร์ ชนิดดูดซึมน้ำต่ำ ทำการขึ้นรูปชิ้นงานกระเบื้องที่มีส่วนผสมของเถ้าหนักลิกไนต์ที่มีอัตราการดูดซึมน้ำเทียบเท่ากับกระเบื้องสโตนแวร์สูตรมาตรฐาน และนำสูตรกระเบื้องที่มีส่วนผสมของเถ้าหนักลิกไนต์ที่มีการดูดซึมน้ำใกล้เคียงกับกระเบื้องสูตรมาตรฐานมาผสมในอัตราส่วนร้อยละ10 ถึงร้อยละ 90 ของกระเบื้องดินเผาสูตรมาตรฐาน เพื่อวิเคราะห์แนวโน้มที่เกิดขึ้นจากการเติมเถ้าหนักลิกไนต์ลงในกระเบื้องดินเผาที่มีผลต่อการแอ่นตัวที่อุณหภูมิสูง และสมบัติที่สำคัญของกระเบื้องเซรามิกสโตนแวร์กระเบื้องดินเผาที่มีการใช้เถ้าหนักลิกไนต์เป็นส่วนผสมมีการแอ่นตัวที่อุณหภูมิสูงน้อยลงตามอัตราส่วนของเถ้าหนักลิกไนต์ที่เพิ่มขึ้น กระเบื้องดินเผา (สูตร T3) ประกอบด้วยเถ้าหนักลิกไนต์ร้อยละ 50 ดินดำแม่ทานร้อยละ 30 ดินขาวลำปางร้อยละ 10 โซเดียมเฟลสปาร์ร้อยละ 5 และทรายบดร้อยละ 5 โดยน้ำหนัก มีการค่าแอ่นตัว 1.29x10-6 ต่อมิลลิเมตร เทียบกับกระเบื้องสูตรมาตรฐาน (สูตร STD) ประกอบด้วย ดินดำแม่ทานร้อยละ 30 ดินขาวลำปางร้อยละ 30 หินผุร้อยละ 30 โซเดียมเฟลสปาร์ร้อยละ 5 และทรายบดร้อยละ 5 โดยน้ำหนัก มีค่าการแอ่นตัว 3.39x10-6 ต่อมิลลิเมตร เนื่องจากในเถ้าหนักลิกไนต์ มีองค์ประกอบของแคลเซียมออกไซด์เป็นตัวทำให้เกิดเฟสอนอร์ไทต์ที่มีผลึกรูปเข็ม และช่วยให้ค่าการแอ่นตัวน้อยลงตามปริมาณของเฟสอนอร์ไทต์ที่เกิดขึ้น นอกจากนี้การเติมเถ้าหนักลิกไนต์ในอัตราส่วนที่เหมาะสมยังช่วยลดปริมาณการดูดซึมน้ำโดยกระเบื้องดินเผา (สูตร T30) ที่มีเถ้าหนักลิกไนต์ร้อยละ 15 ดินดำแม่ทานร้อยละ 30 ดินขาวลำปางร้อยละ 24 หินผุร้อยละ 21 โซเดียมเฟลสปาร์ร้อยละ 5 และทรายบดร้อยละ 5 โดยน้ำหนัก มีค่าการดูดซึมน้ำ 0.99 เปอร์เซ็นต์ เทียบกับกระเบื้องสูตรมาตรฐานที่ 3.15 เปอร์เซ็นต์

อิทธิพลของการเจือ ไนโอเบียม อินเดียม และ อะลูมิเนียม ในไทเทเนียมไดออกไซด์เซรามิกต่อสมบัติทางไดอิเล็กทริก, ยุทธพิชัย ขำมณี

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในงานวิจัยนี้ได้ศึกษาและพัฒนาสมบัติทางไฟฟ้าของวัสดุไดอิเล็กทริกไทเทเนียมได-ออกไซด์เซรามิกส์ ด้วยการเจือ ไนโอเบียมออกไซด์ อินเดียมออกไซด์ และอะลูมิเนียมออกไซด์ การสังเคราะห์ทำได้ด้วยวิธีการปฏิกิริยาสถานะของแข็ง จากการเผาผนึกที่อุณหภูมิ 1,450 องศาเซลเซียส ยืนไฟเป็นเวลา 10 ชั่วโมง ได้มีการแบ่งกลุ่มตัวอย่างออกเป็น 3 กลุ่ม ได้แก่ กลุ่มที่ 1 การเจือไทเทเนียมไดออกไซด์ด้วยไนโอเบียมและอินเดียมร่วมกันที่ความเข้มข้น 1, 5 และ 7 เปอร์เซ็นต์โดยโมล ทำให้ค่าคงที่ไดอิเล็กทริกที่สูงเพิ่มสูงขึ้นจาก 400 เป็น 600, 8,000 และ 14,000 ตามลำดับ กลุ่มที่ 2 การเจือไทเทเนียมไดออกไซด์ด้วยไนโอเบียมและอินเดียมที่ความเข้มข้น 5 เปอร์เซ็นต์โดยโมล และปรับองค์ประกอบของของอินเดียมแบบขาดและเกินอัตราส่วนของ ไนโอเบียมและอินเดียม ได้แก่ 0.50:0.47, 0.50:0.48, 0.50:0.49, 0.50:0.51, 0.50:0.52 และ 0.50:0.53 พบว่าค่าคงที่ไดอิเล็กทริกของตัวอย่างที่มีความเข้มข้นของอินเดียมขาด มีค่า 28,000, 22,000 และ 30,000 ตามลำดับซึ่งโดยรวมมีค่าสูงกว่าตัวอย่างที่มีความเข้มข้นของอินเดียมเกินซึ่งมีค่า 17,000, 12,000 และ 13,000 ตามลำดับ กลุ่มที่ 3 การเจือไทเทเนียมไดออกไซด์ด้วยไนโอเบียม อินเดียมและอะลูมิเนียม 5 เปอร์เซ็นต์โดยโมล อัตราส่วนของ ไนโอเบียม อินเดียมและอะลูมิเนียม ได้แก่ 0.005:0.475:0.025, 0.005:0.450:0.050 และ 0.005:0.425:0.075 มีสมบัติที่โดดเด่นทางกายภาพและไฟฟ้า การตรวจสอบเฟสด้วยเทคนิคการเลี้ยวเบนรังสีเอกซ์ไม่พบการเปลี่ยนแปลงของเฟส หรือการเกิดเฟสที่แปลกปลอม ขนาดเกรนเฉลี่ย 25.94, 23.24 และ 40.20 ไมโครเมตร มีค่าคงที่ไดอิเล็กทริก 27,000, 25,000 และ 43,000 ตามลำดับและมีความเสถียรในช่วงความถี่ 102-106 เฮิร์ต และ จากอุณหภูมิห้องถึง 300 องศาเซลเซียส

Synthesis And Behavior Characterization Of Multi-Scale Hierarchical Structured Composites, Jacob M. Mayfield

College of Graduate Studies: Theses & Dissertations

The purpose of the synthesis of a multi-scale hierarchical composite material was to create a material with a high specific strength, a low mass, and high strength material. To achieve this the material categorization of the Formlabs Tough V2 resin was conducted. The resin was used in the construction of a bio-mimicry diamond lattice structure. The structure was subjected to compression testing to characterize the material properties. The Tough V2 resin structure combined with cellulose created a multi-scaled material on Macro and Micro levels to show the bio-inspired design to increase the material properties in a favorable manor. The Tough …

Development Of Oxide-Dispersion-Strengthened Nickel-Based Super Alloy Powders For Additive Manufacturing, Sizhe Huang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Oxide-Dispersion-Strengthened (ODS) Nickel-Based superalloy has been drawn a huge attention and developed with good oxidation resistance, corrosion resistance and high creep strength. It has been considered as critical materials for Additive Manufacturing (AM). The quality and the efficiency of fabrication methods of ODS limits the performance of itself on AM. The development of new type of ODS, new methodologies and evaluation techniques are required if the enhanced quality of ODS and enhanced efficiency of fabrication are to be achieved. Of the current fabrication techniques for AM, Gas Atomization (GA) is widely used since they can generate spherical powders with high …

Bio-Mimetic Design With 3d Printable Composites, Ramya Mitra Patnam Damodaram

Electronic Theses and Dissertations

Weight and stiffness are key factors in the advancement of materials and parts for use in numerous industries. Lightweight cellular structures are broadly utilized for this reason. However, these structures must satisfy several key constraints: they should be light yet structurally safe, sustainable in different loading conditions, resource efficient and easy to maintain. Bio-inspired materials/structures which results in desirable material features are a significant inspiration for engineered cellular structures. Cellular structures can be designed to have multifunctional properties along with lightweight characteristics. Currently, these structures with high strength to weight ratio are widely applied in many fields such as automotive, …

Evaluation Of The Effect Of Tack Coat Type, Application Rate, And Surface Type On Interlayer Shear Strength, Chamika Prashan Dharmarathna

Electronic Theses and Dissertations

Tack coat is an asphaltic material applied between asphalt pavement layers. Since pavement is a multilayered structure, it is highly important to make proper bond between the layers to achieve a monolithic behavior. Hence, inadequate bond due to application of inadequate amount of tack coat may lead to poor structural behavior and premature failure. Also, applying excessive amount of tack coat may lead to layer slippage and binder migration. Therefore, it is highly important to apply an optimum amount of tack coat between layers. Over the past decades several studies have been conducted to determine the optimum tack coat application …

Thickness Dependence Of Electrical Conductivity In A Thin Film Thermoelectric Composite, David Zagaceta, William Rogers, Andres Breucop, Brian Herrera

Math 365 Class Projects

In this work we utilize the Van Der Pauw method for measuring and calculating the electrical conductivity of a composite material in relation to its thickness.

Plasmon-Enhanced Optical Sensing By Engineering Metallic Nanostructures, Peng Zheng

Graduate Theses, Dissertations, and Problem Reports (ETD)

The world’s booming population projected to reach 10 billion by 2050 causes enormous stresses on environmental safety, food supply, and healthcare, which in return threatens human civilizations. One of the most promising solutions lies at innovating point-of-care (POC) sensing technologies to conduct detection of environmental hazards, monitoring of food safety, and early diagnosis of diseases in a timely and accurate manner. The discovery of surface-enhanced spectroscopy in the 1970s has significantly stimulated research on light-matter interaction which gives rise to enhanced optical phenomena such as surface-enhanced Raman scattering (SERS), plasmon-enhanced fluorescence (PEF), and particularly, they have found enormous applications in …

An Injectable Thermosensitive Biodegradable Hydrogel Embedded With Snap Containing Plla Microparticles For Sustained Nitric Oxide (No) Delivery For Wound Healing, Nikhil Mittal

Dissertations, Master's Theses and Master's Reports

After injury, wound healing is a complex sequential cascade of events essential for the proper recovery of the wound without the scar formation. Nitric oxide (NO) is a small, endogenous free-radical gas with antimicrobial, vasodilating and growth factor stimulating properties. NO has wide biomedical application especially in wound healing however, its usability is hindered due its administration problem as it is highly unstable.

In this work, poly (l-lactic acid) microparticles encapsulated with NO donor S-nitroso-N-acetyl-D-penicillamine (SNAP) were prepared using water-in-oil-water double emulsion solvent evaporation method for controlled delivery for NO at the specific site. The NO release from SNAP-PLLA microparticles …

Mse Annual Report 2018, Department Of Materials Science And Engineering, Michigan Technological University

Department of Materials Science and Engineering Annual Reports

Table of Contents

• Faculty and Staff News
• STEM Feature
• Student News
• Senior Design Teams
• Graduate Student News
• Outreach
• Alumni News
• By the Numbers
• Michigan Tech Foundry Fund

A Scientific Approach To Understanding The Head Trauma Endured By A Mixed Martial Arts Fighter, John William Michael Sorbello

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this research is to gain some insight on the type of head trauma an athlete may encounter during mixed martial arts (MMA) competition. These athletes endure continuous blows to the head throughout their training and fighting career. The knowledge obtained from this research may assist MMA athletes and trainers in assessing the way they train, how they compete and, more importantly, how long they choose to compete in their amateur or professional MMA career.

The analysis is performed by first creating a three-dimensional solid model of the human head based on geometric coordinates originally obtained from a …

Studying Mass And Mechanical Property Changes During The Degradation Of A Bioadhesive With Mass Tracking, Rheology And Magnetoelastic (Me) Sensors, Zhongtian Zhang

Dissertations, Master's Theses and Master's Reports

In this research, the degradable polymer 4-arm poly (ethylene glycol)-glutaric acid-dopamine (PEG-GA-DM₄) was synthesized. The degradation behavior of crosslinked PEG-GA-DM₄ bioadhesive was studied with mass tracking, oscillatory rheology, and magnetoelastic (ME) sensors. Changes in mechanical properties were correlated with both dry mass and wet mass changes during the degradation. The results indicate that the loss of mechanical property in the bioadhesive can take place without losing the dry mass. The mass loss profile cannot describe the degradation behavior completely. In addition to studying the degradation of PEG-GA-DM₄, this research also confirms the application of ME …

Nondestructive Evaluation Of Salvage White Spruce, Tyler Hovde

Dissertations, Master's Theses and Master's Reports

Knowledge of wood quality in dead standing trees is an important topic with recent increases in defoliation across North America. Obtaining wood quality information for defoliated trees would help stakeholders in the timber products industry sort and sell salvaged material for the highest possible value. This research investigates the ability to measure wood quality of white spruce (Picea glauca) after spruce budworm (Choristoneura fumiferana) attack using acoustic nondestructive evaluation. We compared stress wave velocities measured on standing trees to trees’ visual appearance. After harvest and processing of selected trees into bolts, standing-tree stress wave velocities were compared to bolt acoustic …

Fundamental Studies Of Chemical Stability And Carrier Process In Hybrid Perovskite Materials, Jue Gong

Graduate Research Theses & Dissertations

This dissertation comprehensively studies the optoelectronic properties of organic-inorganic hybrid perovskites to fundamentally answer their foundations of outstanding performance on solar cells, photodetectors, nanowire lasers and other optoelectronic applications. Specifically, a novel type of charge carrier-lattice interaction was discovered in perovskite methylammonium lead iodide (CH3NH3PbI3), where photoluminescence lifetime of photoinduced carriers is strongly dependent on the rotational frequency of CH3NH3+, as modulated via substitution of hydrogens with deuterium atoms in the organic cation. In addition, two-dimensional Ruddlesden-Popper perovskite (CH3NH3)2Pb(SeCN)2I2 was first synthesized and characterized in the field, and its photoluminescence properties were systematically examined. The existence of intensive photoluminescence peak …

Surface Engineering And Monomer Design For Light-Mediated Ring Opening Metathesis Polymerization, Ishan A. Fursule

Theses and Dissertations--Chemical and Materials Engineering

Stimuli-responsive materials are changing the landscape of actuated materials, optoelectronics, molecular machines, solar cells, temporary memory storage, and biomedical materials. Specifically, photo-responsive polymers have gained acceleration in research and application since the last two decades in the form of a surface coating and micro-patterns. Light as a stimulus can be coherent, mono or polychromatic, tunable for power (intensity) and energy (wavelength), and has precise spatiotemporal control. Conventional surface coating techniques such as spin coating are unable to impart properties to the coatings in terms of sturdiness, homogeneity, uniformity over the complex surface, post deposition modification, and process efficiency. Also, in …

Combinatorial Screening Approach In Developing Non-Equiatomic High Entropy Alloys, Azin Akbari

Theses and Dissertations--Chemical and Materials Engineering

High entropy alloys (HEA) are a relatively new group of alloys first introduced in 2004. They usually contain 5 to 6 different principle elements. Each of these elements comprise 5-35 at. % of the chemical composition of the alloy. There is a growing interest in the research community about the development of these alloys as well as their engineering applications. Some HEAs have interesting properties that have made them well suited for higher temperature applications, particularly refractory uses, while some have been shown to maintain their mechanical properties even at cryogenic temperatures.

Initially, the HEA research was focused on developing …

A Microstructure-Based Model Validated Experimentally For Quantification Of Short Fatigue Crack Growth In Three-Dimensions, Pei Cai

Theses and Dissertations--Chemical and Materials Engineering

Built on the recent successes in understanding the crystallographic mechanism for short fatigue crack (SFC) growth across a grain boundary (GB) and developing an experimental method to quantify the GB resistance against short crack growth, a microstructure-based model was developed in this study to simulate the growth behaviors of SFCs in 3-D, by taking into account both the driving force and resistance along at each point along the crack front in an alloy. It was found that the GB resistance was a Weibull function of the minimum twist angle of crack deflection at the boundary in AA2024-T3 Al alloys. In …

Defect Chemistry And Transport Properties Of Solid State Materials For Energy Storage Applications, Xiaowen Zhan

Theses and Dissertations--Chemical and Materials Engineering

Replacing organic liquid electrolytes with nonflammable solid electrolytes can improve safety, offer higher volumetric and gravimetric energy densities, and lower the cost of lithium-ion batteries. However, today’s all-solid-state batteries suffer from low Li-ion conductivity in the electrolyte, slow Li-ion transport across the electrolyte/electrode interface, and slow solid-state Li-ion diffusion within the electrode. Defect chemistry is critical to understanding ionic conductivity and predicting the charge transport through heterogeneous solid interfaces. The goal of this dissertation is to analyze and improve solid state materials for energy storage applications by understanding their defect structure and transport properties.

I have investigated defect chemistry of …

Mixed Matrix Flat Sheet And Hollow Fiber Membranes For Gas Separation Applications, Nicholas W. Linck

Theses and Dissertations--Chemical and Materials Engineering

Mixed matrix membranes (MMM) offer one potential path toward exceeding the Robeson upper bound of selectivity versus permeability for gas separation performance while maintaining the benefits of solution processing. Many inorganic materials, such as zeolites, metal-organic frameworks, or carbon nanotubes, can function as molecular sieves, but as stand-alone membranes are brittle and difficult to manufacture. Incorporating them into a more robust polymeric membrane matrix has the potential to mitigate this issue.

In this work, phase inversion polymer solution processing for the fabrication and testing of asymmetric flat sheet mixed matrix membranes was employed with CVD-derived multiwall carbon nanotubes (MWCNTs) dispersed …

The Formation Mechanism Of Α-Phase Dispersoids And Quantification Of Fatigue Crack Initiation By Experiments And Theoretical Modeling In Modified Aa6061 (Al-Mg-Si-Cu) Alloys, Gongwang Zhang

Theses and Dissertations--Chemical and Materials Engineering

AA6061 Al alloys modified with addition of Mn, Cr and Cu were homogenized at temperatures between 350 ^ºC and 550 ^ºC after casting. STEM experiments revealed that the formation of α-Al(MnFeCr)Si dispersoids during homogenization were strongly affected by various factors such as heating rate, concentration of Mn, low temperature pre-nucleation treatment and homogenization temperature. Through analysis of the STEM results using an image software Image-Pro, the size distributions and number densities of the dispersoids formed during different annealing treatments were quantitatively measured. It was revealed that increasing the heating rate or homogenization temperature led to a reduction of …

Synthesis And Characterization Of Magnesium - Titanium Composites By Severe Plastic Deformation, Baleegh Alobaid

Theses and Dissertations--Chemical and Materials Engineering

Magnesium alloys are widely used in engineering applications, including aerospace and automobile industries, due to their desirable properties, such as lower density, high damping capacity, relatively high thermal conductivity, good machinability, and recyclability. Researchers have, therefore, been developing new magnesium materials. However, mechanical and corrosion properties are still limiting many commercial applications of magnesium alloys. In this Ph.D. thesis research, I developed Mg-Ti composite materials to offer some solutions to further improve the mechanical behavior of magnesium, such as titanium-magnesium (Ti-Mg) claddings, Mg-Ti multilayers, and Ti particle enforced Mg alloys. Low cost manufacturing processes, such as hot roll-bonding (RB) and …

The Physical Behavior And Characterization Of Nanoporous Silicon And Dispenser Cathode Surfaces, Tyler Lucius Corey Maxwell

Theses and Dissertations--Chemical and Materials Engineering

Nanostructured materials have received a surge of interest in recent years since it has become apparent that reducing the size of a material often leads to heightened mechanical behavior. From a fundamental standpoint, this stems from the confinement of dislocations. Applications in microelectromechanical devices, lithium ion batteries, gas sensing and catalysis are realized by combining the improvements in mechanical behavior from material size reduction with the heightened chemical activity offered by materials with a high surface-area-to-volume ratio. In this study, films of nanoporous Si-Mg were produced through magnetron sputtering, followed by dealloying using an environmentally benign process with distilled water. …

Morphological And Energetic Effects On Charge Transport In Conjugated Polymers And Polymer-Nanowire Composites, Zhiming Liang

Theses and Dissertations--Chemistry

Organic semiconductors have wide applications in organic-based light-emitting diodes, field-effect transistors, and thermoelectrics due to the easily modified electrical and optical properties, excellent mechanical flexibility, and solution processability. To fabricate high performance devices, it is important to understand charge transport mechanisms, which are mainly affected by material energetics and material morphology. Currently it is difficult to control the charge transport properties of new organic semiconductors and organic-inorganic nanocomposites due to our incomplete understanding of the large number of influential variables. Molecular doping of π-conjugated polymers and surface modification of nanowires are two means through which charge transport can be manipulated. …

Comparative Study Of Cv3 Carbonaceous Chondrites Allende And Bali Using Micro-Raman Spectroscopy And Sem/Eds, Raka Paul

All Graduate Theses, Dissertations, and Other Capstone Projects

The birth of the solar system (over 4 billion years) is speculated to have happened from a nebula, swirling and compacting in localized regions to eventually form the Sun and planets. This complex process consists of numerous changes and intermediary steps, yet to be fully understood. Carbonaceous chondritic meteorites are relics of that process and therefore have potential to reveal information about the formation history. Several theories have been formulated linking their composition to planet formation. This study focusses on two carbonaceous chondritic specimens, Allende and Bali, both of the group CV and petrologic type 3. CV meteorites are abundant …

Nonlinear Coupled Effects In Nanomaterials, Sia Bhowmick

Theses and Dissertations (Comprehensive)

Materials at the nanoscale have different chemical, structural, and optoelectrical properties compared to their bulk counterparts. As a result, such materials, called nanomaterials, exhibit observable differences in certain physical phenomena. One such resulting phenomenon called the piezoelectric effect has played a crucial role in miniature self-powering electronic devices called nanogenerators which are fabricated by using nanostructures, such as nanowires, nanorods, and nanofilms. These devices are capable of harvesting electrical energy by inducing mechanical strain on the individual nanostructures. Electrical energy created in this manner does not have environmental limitations. In this thesis, important coupled effects, such as the nonlinear piezoelectric …