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Articles 91 - 120 of 244

Full-Text Articles in Materials Science and Engineering

Nature Inspired Technology: A New Process For Silicification Based On Marine Sponges, Ami Atul Shah May 2018

Nature Inspired Technology: A New Process For Silicification Based On Marine Sponges, Ami Atul Shah

Material Science and Engineering Dissertations - Archive

Silica is used in various industries, ranging from automobile industry for tires to semiconductor industry, paints and coatings, biomedical devices & applications to food & drug industry. The current processing techniques for precipitated silica involve harsh conditions like high temperature and extreme pH conditions. Nature already has highly evolved production techniques for silica. They run at physiological conditions and exhibit intricate control over the synthesis, leading to very pure and ornate siliceous structures. These structures exhibit organized architecture at scales as small as nano-dimensions. The proposed research work is a step, towards development of new techniques that bio-mimic the silica …

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Investigation Of The Processing-Structure-Property Relationship In Ta-Si-N Nanocomposite Coatings, Anna Zaman May 2018

Investigation Of The Processing-Structure-Property Relationship In Ta-Si-N Nanocomposite Coatings, Anna Zaman

Material Science and Engineering Dissertations - Archive

The present-day industry demands development of coatings for harsh environmental applications which can resist impact and oxidation at high temperatures. It is vitally important to develop new hard (>30 GPa) protective coatings which will be thermally stable at temperatures, T > 800 °C and simultaneously will ensure a good protection of the substrate against oxidation from an external atmosphere. The limitations of conventional coatings due to inferior hardness or poor oxidation stability can be overcome by nanocomposite coatings as they exhibit enhanced and completely new properties. To address this requirement of new enhanced protective systems, there is a need to …

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Dielectric Property Investigation Of Degraded Pre-Preg And Performance Prediction Of The Final Composite Part, Aishwarya Nandini, Nina Shute, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider May 2018

Dielectric Property Investigation Of Degraded Pre-Preg And Performance Prediction Of The Final Composite Part, Aishwarya Nandini, Nina Shute, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

In recent years, fiber-reinforced (i.e., Glass, Carbon, Kevlar) epoxy composites are used widely in structural applications ranging from military and civil aircraft production to recreational consumer products. Most of the industries use pre-impregnated varieties of composite (prepregs) to make high-quality composite parts. Despite their various advantages, prepreg materials are unstable at ambient temperature. A realistic estimation of the shelf life of prepreg is therefore essential for maintaining quality while reducing wastage of resources. Prepregs are temperature and moisture sensitive material systems. To achieve prolonged shelf life, manufacturer and seller of the prepreg must store the materials at zero degrees Celsius …

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Effects Of Build Parameters On The Mechanical And Di-Electrical Properties Of Am Parts, Sai Sri Munaganuru, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rauhon Ahmed Shaik, Hari K. Adluru, Rassel Raihan Jan 2018

Effects Of Build Parameters On The Mechanical And Di-Electrical Properties Of Am Parts, Sai Sri Munaganuru, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rauhon Ahmed Shaik, Hari K. Adluru, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Additive manufacturing (AM) revolutionized many industries, i.e., Automotive, Biomedical, Aerospace and Defense. As opposed to traditional manufacturing methods, a part is manufactured layer by layer from 3D CAD models in AM. Though the vision of AM is impressive, there are many challenges that are hindering the widespread use of these complex parts. One of the challenges in these materials is defects grow and their orientation during the manufacturing process. In this paper we are going to investigate the effect of Build Parameters and their effects on the mechanical and electrical properties of the additively manufactured heterogeneous material system. We will …

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Data Driven Composites: The Challenge And Paths Forwards, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider Jan 2018

Data Driven Composites: The Challenge And Paths Forwards, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

The concept of “data driven” grew out of the general subject of data analytics, especially in the business world. The classical sequence proposed by Dykes (2010) shown below illustrates the general contents of the concept. Indeed, the idea of “predictive modeling” of the future behavior of a system has strong roots in the business community. In general, for engineering and other fields, the data driven challenge is to use the past with information from the present to predict the future behavior of a system. In turn, the user must pay for collection and processing, hosting and maintenance of the data, …

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State Variable Methods Of Assessment, Prognosis, And Control Of Composite And Bonded Structures, Kenneth Reifsnider, Rassel Raihan, Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian Jan 2018

State Variable Methods Of Assessment, Prognosis, And Control Of Composite And Bonded Structures, Kenneth Reifsnider, Rassel Raihan, Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

It is generally recognized that the determination of material state is the baseline foundation for the assessment and prognosis of current and future performance of structural materials in which distributed damage leads to progressive property degradation. Many classes of composite materials, both naturally occurring and engineering designs, are governed by such behavior. However, finding appropriate measureable physical variables to make such assessments, especially for as-manufactured and subsequent real-time assessment and prognosis conditions is challenging. Measurement and analysis of multiple single defect initiation, interaction, and collective effects is the most rigorous current methodology, and is the foundation for certification and quality …

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Global Prediction Of Discrete Local Damage Interactions Using Broadband Dielectric Spectroscopy, Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian, Rauhon Ahmed Shaik, Aishwarya Nandini, Rassel Raihan, Kenneth Reifsnider Jan 2018

Global Prediction Of Discrete Local Damage Interactions Using Broadband Dielectric Spectroscopy, Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian, Rauhon Ahmed Shaik, Aishwarya Nandini, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

With the increasing demand for composites in many modern applications, it is important to predict the initiation of failure events. Due to the heterogeneous nature of these materials, a single damage mode will not lead to final failure, hence detecting the initiation and growth of a single crack (defect) will not yield accurate predictions of the strength or the material state. It is important to capture the interaction of various damage modes that tend to change the material state leading to initiation of failure. To assess the material state, one needs to determine the appropriate global physical variables that can …

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Molecular Dynamics For The Prediction Of The Interfacial Shear Stress And Interface Dielectric Properties Of Carbon Fiber Epoxy Composites, Rajni Chahal, Ashfaq Adnan, Kenneth Reifsnider, Rassel Raihan, Yuan Ting Wu, Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian Jan 2018

Molecular Dynamics For The Prediction Of The Interfacial Shear Stress And Interface Dielectric Properties Of Carbon Fiber Epoxy Composites, Rajni Chahal, Ashfaq Adnan, Kenneth Reifsnider, Rassel Raihan, Yuan Ting Wu, Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

The thermoset epoxy resin Diglycidyl ether of Bisphenol F (EPON 862), crosslinked with the Diethylene Toluene Diamine (DETDA) hardening agent, are utilized as the polymer matrix component in many graphite (carbon fiber) composites. Since it is difficult to experimentally characterize the interfacial region, computational molecular modeling is a necessary tool for understanding the influence of the interfacial molecular structure on bulk-level material properties. The purpose of this research is to evaluate and compare the interfacial shear stress and dipole moment for the pristine carbon fiber composite and the one with the moisture content at the interface. Molecular models are established …

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Investigation Of Thermophysical Properties Of Enhanced Molten Salt Nanofluids For Thermal Energy Storage (Tes) In Concentrated Solar Power (Csp) Systems, Joohyun Seo Dec 2017

Investigation Of Thermophysical Properties Of Enhanced Molten Salt Nanofluids For Thermal Energy Storage (Tes) In Concentrated Solar Power (Csp) Systems, Joohyun Seo

Material Science and Engineering Dissertations - Archive

Concentrated solar power (CSP) technologies have a great economical and technical potential for energy production in future. Its incorporation with thermal energy storage (TES) overcomes one of the biggest challenges in most renewable energy technologies, the intermittency of energy supply by natural resources. TES with 15-hour storage capacity is already commercialized to operate a CSP plant for 24 hours a day. When the sunlight is concentrated by mirrors into a small focal point, a heat transfer fluid (HTF) transfers the collected heat to a turbine or an engine to produce electricity and any surplus heat to a TES unit for …

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Development Of Plasma Functionalized Nano-Additives For Oils And Study Of Their Tribological Properties, Vinay Sharma Dec 2017

Development Of Plasma Functionalized Nano-Additives For Oils And Study Of Their Tribological Properties, Vinay Sharma

Material Science and Engineering Dissertations - Archive

Lubricants used in motor engines contain various chemical species to help enhance energy efficiency and provide increased longevity. Unfortunately, at the same time, these additives become a source of catalytic poisoning, thus increasing emissions from the tailpipe. With growing concern for the negative impacts of human activities on the environment, regulatory bodies for the automobile lubrication industry have set up strict guidelines for chemical compositions of their end products, including engine oils. This research work is a step towards development of a new class of lubricant additives, which are less harmful to the environment and, simultaneously, also reduce friction and …

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Study Of Defect Coalescence In Heterogeneous Material Systems Using Broad Band Dielectric Spectroscopy., Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian, Priyanshu Kumar Banerjee, Rassel Raihan, Kenneth Reifsnider Nov 2017

Study Of Defect Coalescence In Heterogeneous Material Systems Using Broad Band Dielectric Spectroscopy., Vamsee Vadlamudi, Muthu Ram Prabhu Elenchezhian, Priyanshu Kumar Banerjee, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Composite materials are essential for many modern applications, including airplanes and cars, energy conversion and storage devices, medical prosthetics, and civil structures. Detecting the initiation, growth, accumulation, and coalescence of micro-damage in these heterogeneous materials and predicting the onset of component failure using conformal Broadband Dielectric Spectroscopy (BbDS) is a promising area of ongoing research. Recently, the authors have developed the critical path concept and Heterogeneous fracture mechanics concept that depicts the effect of defect nucleation, growth, coalescence, and fracture plane development and correlation of these damage mechanisms to change in dielectric response respectively. Current research applies those concepts to …

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Predicting Adhesive Bond Performance Based On Initial Dielectric Properties, Priyanshu Kumar Banerjee, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider Oct 2017

Predicting Adhesive Bond Performance Based On Initial Dielectric Properties, Priyanshu Kumar Banerjee, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Rassel Raihan, Kenneth Reifsnider

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

This paper will focus on an approach to study the mechanical as well as the dielectric properties of an adhesive bond. The dielectric testing is done by using Broadband Dielectric Spectroscopy (BbDS), wherein the dielectric characteristics of the material are analyzed in a wide frequency spectrum. The data obtained by this technique are used to demonstrate the charge transport, the combined dipolar fluctuation, and the effects of polarization occurring between the boundaries of materials. The continuous modifications of the dielectric spectra are due to the changes in the electrical and structural interactions between the particles, shapes, and orientations of the …

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Nanosilica Based 3d Printed Scaffold Facilitate Osteoblast Mineral Formation, Tugba Cebe Aug 2017

Nanosilica Based 3d Printed Scaffold Facilitate Osteoblast Mineral Formation, Tugba Cebe

Material Science and Engineering Theses - Archive

Bone has the ability to heal fractures so long as the size of the fracture is sufficiently small. If the defect is large or of critical size, a filling material or graft will be needed to help bone union. Among all the available methods to address this medical condition, the common drawback of grafts is that they are limited in supply since a biological site or organism is needed to harvest the biological graft. As a new approach, researchers have been working with bioceramics and biopolymers for their use in bone tissue engineering. In this work, chitosan was modified with …

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Processing Beta-Tricalcium Phosphate And 45s5 Bioglass Mixtures For Osteogenic Bone Tissue Scaffolds, Phillip Zachary James Aug 2017

Processing Beta-Tricalcium Phosphate And 45s5 Bioglass Mixtures For Osteogenic Bone Tissue Scaffolds, Phillip Zachary James

Material Science and Engineering Theses - Archive

A 30% 45S5 Bioglass and 70% -tricalcium phosphate ceramic mixture, which was previously shown to be osteogenic [1], was sintered and the process was investigated as a strengthening mechanism. Samples were sintered for dwell times of 1,2, and 4 hrs at 500°C to avoid crystallization of the 45S5 Bioglass. Two different binders were used, 2% gelatin in deionized water and 2% laponite with 2% oleic acidin deionized water. The mixture was also robocasted as a slurry to evaluate the manufacturing process. Mechanical compression testing shows that the laponite with oleic acid binder acted as a sintering aid leading to a …

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Investigation Of Microstructure Effects On Hardness And Oxidation Resistance Of New Generation Ceramic Coatings, Minghui Zhang Aug 2017

Investigation Of Microstructure Effects On Hardness And Oxidation Resistance Of New Generation Ceramic Coatings, Minghui Zhang

Material Science and Engineering Dissertations - Archive

This work was motivated by the demand for a new generation of materials capable for harsh environment applications, and focused on developing a better understanding of the effects of elemental composition and microstructure on the mechanical and thermal properties of coatings. The knowledge gained from this work can be used to design protective coatings with tailored properties for harsh environment applications in the future. High resolution transmission electron microscopy (HRTEM) and electron diffraction have been mainly employed in the microstructure studies of the new generation ceramics, with the assistance of other materials characterization techniques, such as x-ray diffraction (XRD), x-ray …

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Investigation Of The Plasma Electrolytic Oxidation Mechanism Of Titanium, Golsa Mortazavi Aug 2017

Investigation Of The Plasma Electrolytic Oxidation Mechanism Of Titanium, Golsa Mortazavi

Material Science and Engineering Dissertations - Archive

Plasma electrolytic oxidation (PEO) is an environmentally friendly technology capable of forming coatings with excellent adhesion strength at high deposition rates. The PEO process is particularly attractive for forming desirable oxide-based coatings in transition metals (Al, Ti, Mg) to improve their surface sensitive properties. At present, the PEO mechanism is not fully understood since the process includes complex processes that are difficult to study. However, understanding the PEO mechanism is essential to produce coatings with desirable characteristics for a variety of new applications. One critical PEO process parameter is the applied total current to the workpiece. The total applied current …

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Ag Nano-Dendritic Three-Dimensional (3d) Surface-Enhanced Raman Scattering (Sers) Substrate For In-Situ Liquid Media Detection, Milind Mansing Pawar May 2017

Ag Nano-Dendritic Three-Dimensional (3d) Surface-Enhanced Raman Scattering (Sers) Substrate For In-Situ Liquid Media Detection, Milind Mansing Pawar

Material Science and Engineering Theses - Archive

Continuous monitoring of certain environmental pollutants, biological species, chemical species, and explosives are of utmost importance in recent times. Surface-enhanced Raman scattering (SERS) provides most promising option as it is a highly sensitive technique which allows for ultrasensitive detection of molecules and provides excellent structural information. To obtain rich results through Surface-enhanced Raman scattering, proper design of enhancing substrate plays vital role. Contemporary SERS substrates don’t provide ease to detect liquid analytes for in-situ spectroscopy. Liquid media detection through SERS relies on highly statistical binding of analytes to SERS-sensitive hot spots. Moreover, it becomes extremely difficult to detect flowing liquid …

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Quality Assessment Of Adhesive Bond Based On Dielectric Properties, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Priyanshu Kumar Banerjee, Chaitanya Dave, Anik Mahmood, Rassel Raihan Jan 2017

Quality Assessment Of Adhesive Bond Based On Dielectric Properties, Muthu Ram Prabhu Elenchezhian, Vamsee Vadlamudi, Priyanshu Kumar Banerjee, Chaitanya Dave, Anik Mahmood, Rassel Raihan

Institute of Predictive Performance Methodologies (IPPM-UTARI)-Archive

Composite materials are widely used in Aerospace, Marine and Automotive structures to reduce weight and increase performance. Adhesive bonding improves the stress distribution between the composite materials / dissimilar materials and ensures a lighter structure than conventional fastener joints. But still there is not much research on the Non-Destructive strength estimation and life prediction, or the damage prognosis of the adhesive bond. One of the main problems when using adhesive bonding is a "kissing bond" which is a weak adhesion bond alternatively called zero volume disbond. Typically, convectional non-destructive methods cannot detect this kissing bond. Broadband Dielectric Spectroscopy, BbDS, is …

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The Influence Of The Interaction Of Carbon Based Materials With Ionic Liquid On The Tribological Performance Of Lubricating Grease And Oil, Kimaya Vyavhare Dec 2016

The Influence Of The Interaction Of Carbon Based Materials With Ionic Liquid On The Tribological Performance Of Lubricating Grease And Oil, Kimaya Vyavhare

Material Science and Engineering Theses - Archive

Stringent government regulation on environment emissions and demand to develop energy efficient and durable modern mechanical systems has imposed a significant challenge on the lubricant additive manufacturer to develop environment friendly and high performance additives for the lubricating medias like oil and grease. The current industrial additive technology is dominated by phosphorus and sulfur containing the liquid antiwear additive, Zinc dialkyl dithiophosphate and extreme pressure solid additives like Graphite, Molybdenum disulfide. This current additive package possesses harm to the environment and has already met performance limit for applications working under severe operating condition. A proposed solution to combat with this …

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A Novel Approach For Fabrication Of Single Silicon/Silicon Oxide Nanopillars At Precise Locations, Sravan Chowdary Talasila Dec 2016

A Novel Approach For Fabrication Of Single Silicon/Silicon Oxide Nanopillars At Precise Locations, Sravan Chowdary Talasila

Material Science and Engineering Theses - Archive

Nanopillars exhibit novel electrical and optical properties which could not be obtained from bulk materials. Many of their practical applications would require controlled placement of nanopillars at exact locations. However, precise placement and large scale fabrication of nanopillars have been challenging with conventional fabrication techniques. This thesis investigates a new approach to fabricate nanopillars at exact locations on a large scale. In this approach, fabrication of nanopillars is accomplished by first placing nanoparticles (NP) at exact locations and then performing anisotropic dry etching using these NPs as hard masks, resulting in formation of nanopillars on exact substrate positions. Precise placement …

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Electromigration Induced Interface Reaction In Cu-Wire / Al-Pad Diffusion Couple, Patricia Aracelly Rodriguez-Salazar Dec 2016

Electromigration Induced Interface Reaction In Cu-Wire / Al-Pad Diffusion Couple, Patricia Aracelly Rodriguez-Salazar

Material Science and Engineering Dissertations - Archive

This dissertation presents experimental observations that may assist the understanding of electromigration (EM) failure mechanism active in Cu wire and Al thin film pad (wire bond). This study is motivated by an ongoing industrial effort to adapt Cu as wire bonding material for interconnection. Traditional material used for the wire bond has been Au; however, its high cost combined with its susceptibility to reliability failure caused by excessive growth of IMCs (IMC) makes Cu to be an attractive replacement. Though, since an application of Cu to wire bond technology is relatively new, many of reliability failure mechanisms are unknown especially …

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Study Of An All-Vanadium Photoelectrochemical Cell For High-Efficiency Solar Energy Storage, Zi Wei Aug 2016

Study Of An All-Vanadium Photoelectrochemical Cell For High-Efficiency Solar Energy Storage, Zi Wei

Material Science and Engineering Dissertations - Archive

In an attempt to explore a clean and renewable alternative to existing energy sources such as fossil fuel, we studied the feasibility of using vanadium redox species to store the inexhaustible solar energy via photoelectrochemical (PEC) reactions with photogenerated charge carriers from semiconductor photocatalysts such as TiO2. Based on our fundamental study of the compatibility of vanadium redox and TiO2, modification of TiO2 such as carbon coating and geometry enhancement, and development of a continuous-flow solar energy storage cell, we demonstrated high-efficiency solar energy storage cell.The research focuses on the following four directions. Firstly, a highly-efficient all-vanadium (all-V) PEC storage …

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Gold-Nanoparticle-Based Theranostic Agents For Radiotherapy Of Malignant Solid Tumors, Sina Moeendarbari Aug 2016

Gold-Nanoparticle-Based Theranostic Agents For Radiotherapy Of Malignant Solid Tumors, Sina Moeendarbari

Material Science and Engineering Dissertations - Archive

Radiation therapy is one of the three major methods of cancer treatment. The fundamental goal of radiotherapy is to deliver high radiation doses to targets while simultaneously minimizing doses to critical structures and healthy normal tissues. The aim of this study is to develop a general, practical, and facile method to prepare nanoscale theranostic agents for more efficacious radiation therapy with less adverse side effects. First, a novel type of gold nanoparticle, hollow Au nanoparticles (HAuNPs) which was synthesized using the unique bubble template synthesis method developed in our lab, are studied in vitro and in vivo to investigate their …

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Osteogenic Differentiation In Preosteoblast Mc3t3-E1 Cells Induced By Beta Tricalcium Phosphate Bioglass Composite, Chien-Ning Yao Aug 2016

Osteogenic Differentiation In Preosteoblast Mc3t3-E1 Cells Induced By Beta Tricalcium Phosphate Bioglass Composite, Chien-Ning Yao

Material Science and Engineering Theses - Archive

The use of bioactive material from bioceramic and composite components to support bone cell and tissue growth is an interesting area of medical field. Calcium phosphate ceramics are biocompatible and may develop interactions with human living bone tissues. Bioactive calcium phosphates, beta -tricalcium phosphate (β-TCP), have been intensively investigated as the cell scaffold for bone tissue engineering because it is well recognized that they are compatible to natural bone tissue and osteoconductive. In this research we will discuss two types of biomaterial with different kind of composition—(a) a cement type and (b)a scaffold type of biomaterial that can be applied …

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Mechanism Of Wear And Tribofilm Formation With Ionic Liquids And Ashless Antiwear Additives, Vibhu Sharma Aug 2016

Mechanism Of Wear And Tribofilm Formation With Ionic Liquids And Ashless Antiwear Additives, Vibhu Sharma

Material Science and Engineering Dissertations - Archive

Increasingly stringent government regulation on emissions (EPA Emissions Standard Reference Guide and latest CAFE standards requiring an average fuel economy of 54.5 mpg (combined cars and trucks) by 2025) impose significant challenges to the automotive and lubricant industries calling for the development and implementation of lower viscosity ILSAC GF-5&6 and API-CJ4&5 oils which further limit the amount of SAPS and deposits in engines. Development of additives that result in lower ash content, volatility and anti-wear property plays a crucial role in being able to reach these standards. The current industrial additive technology i.e. zinc dialkyldithiophosphate (ZDDP) forms harmful deposits on …

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The Characterization Of Secondary Lithium-Ion Battery Degradation When Operating Complex, Ultra-High Power Pulsed Loads, Derek N. Wong Aug 2016

The Characterization Of Secondary Lithium-Ion Battery Degradation When Operating Complex, Ultra-High Power Pulsed Loads, Derek N. Wong

Material Science and Engineering Dissertations - Archive

The US Navy is actively developing all electric fleets, raising serious questions about what is required of onboard power supplies in order to properly power the ship’s electrical systems. This is especially relevant when choosing a viable power source to drive high power propulsion and electric weapon systems in addition to the conventional loads deployed aboard these types of vessels. Especially when high pulsed power loads are supplied, the issue of maintaining power quality becomes important and increasingly complex. Conventionally, a vessel’s electrical power is generated using gas turbine or diesel driven motor-generator sets that are very inefficient when they …

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Microstructure And Properties Of Hard And Optically Transparent Hfo2 Films Prepared By High-Rate Reactive High-Power Impulse Magnetron Sputtering, Nai-Wen Pi May 2016

Microstructure And Properties Of Hard And Optically Transparent Hfo2 Films Prepared By High-Rate Reactive High-Power Impulse Magnetron Sputtering, Nai-Wen Pi

Material Science and Engineering Theses - Archive

Hafnium Dioxide (HfO2) has an extraordinary high bulk modulus, high hardness, high chemical stability, high melting point and high thermal stability. This material can be used as protective coatings for application involving high temperature environments. HfO2 films were fabricated on Si using high-rate reactive high-power impulse magnetron sputtering (HiPIMS) using different deposition-averaged target power density and voltage pulse durations t1. Five HfO2 films were prepared with (1) t1 = 25 µs, =7.6 Wcm-2 (T25S7), (2) t1 = 100 µs, =7.2 Wcm-2 (T100S7), (3) t1 = 200 µs, =7.3 Wcm-2 (T200S7), (4) t1 = 200 µs, =18 Wcm-2 (T200S18) and (5) …

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Silver Dendrite Based Three-Dimensional Surface Enhanced Raman Scattering (Sers) Substrates, Sandesh Rajkumar Shelke May 2016

Silver Dendrite Based Three-Dimensional Surface Enhanced Raman Scattering (Sers) Substrates, Sandesh Rajkumar Shelke

Material Science and Engineering Theses - Archive

Three-dimensional (3D) hierarchical nanostructures have been considered as one of the most promising surface-enhanced Raman spectroscopy (SERS) substrates because it provides high-density hotspots along the three-dimension directions and high surface areas. In this thesis, we report the synthesis process to develop 3D SERS substrates in thin wall quartz capillary tube on Cu wire. These 3D SERS substrates consist of Ag dendrite, Au-Ag and Pd-Ag bimetallic nanostructures which was synthesized by employing simple galvanic replacement reactions (GRR). In this synthesis process Cu wire which is used as substrate was inserted in the thin walled quartz capillary tube and then AgNO3 was …

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Synthesis And Characterization Of Plasmonic-Magnetic Au-Co Multilayered Nanorods, Akshay Hande May 2016

Synthesis And Characterization Of Plasmonic-Magnetic Au-Co Multilayered Nanorods, Akshay Hande

Material Science and Engineering Theses - Archive

Au nanoparticles (AuNPs) and superparamagnetic iron oxide nanoparticles (SPIONs), in various forms, are considered as biocompatible and are of great interest for diagnostic imaging and therapeutic applications. Biomedical applications of AuNPs originate from the surface plasmon resonance (SPR) effect. In order to tune the SPR wavelength to the near infrared (NIR) region which is required for deep light penetration for in vivo applications, various types of AuNPs such as nanorods, nanoprisms, nanoshells and nanocages have been developed and investigated. SPIONs have also been explored extensively for biomedical applications, including magnetic cell separation, contrast enhancement agents for magnetic resonance imaging (MRI), …

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Studying An All-Vanadium Photoelectrochemical Cell For Highly Efficient Solar Energy Conversion And Storage Via Photocatalytic Redox Reaction, Dong Liu Dec 2015

Studying An All-Vanadium Photoelectrochemical Cell For Highly Efficient Solar Energy Conversion And Storage Via Photocatalytic Redox Reaction, Dong Liu

Material Science and Engineering Dissertations - Archive

This study aims at developing a promising alternative approach to utilize solar energy continuously with high efficiency by employing photocatalytic vanadium redox reactions to overcome major drawbacks associated with conventional photoelectrochemical water splitting. The preliminary study was implemented on TiO2 and WO3/TiO2 by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and zero-resistance ammetry (ZRA) in a photoelectrochemical cell (PEC). The results show much enhanced photoelectrochemical response with the assistance of vanadium(IV, VO2+) redox species. Such photoresponse improvement is attributed to the hole scavenging effect by fast vanadium redox reaction to depress charge recombination at semiconductor/liquid interface in both TiO2 and …

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