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Articles 181 - 210 of 244
Full-Text Articles in Materials Science and Engineering
Synthesis And Characterization Of Carbon Magnetic Nanoparticles, Sunilsingh Gusain
Synthesis And Characterization Of Carbon Magnetic Nanoparticles, Sunilsingh Gusain
Material Science and Engineering Theses - Archive
Carbon incorporated iron nanoparticles (Fe-CNPs) were successfully synthesized using ultrasonic cavitation in Benzene. This novel method of carbon nanoparticle (CNP) synthesis is a very cost-effective and versatile as one can easily tune the microstructure and magnetic properties by varying few parameters, for e.g. voltage. The Fe-CNP complexes are produced due to the electric plasma discharge generated between the electrodes in an ultrasonic cavitation field of liquid benzene. The constituent of the CNPs can be easily modified by different choice of electrode materials- iron and graphite. The resultant Fe-CNPs were characterized by high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy to …
Microstructural Evolution Of Surface Layers During Electrolytic Plasma Processing, Cristian Cionea
Microstructural Evolution Of Surface Layers During Electrolytic Plasma Processing, Cristian Cionea
Material Science and Engineering Dissertations - Archive
Electrolytic Plasma Processing is an emerging technology for surface modification. The EPP process is based on electrolysis of an aqueous electrolyte by application of an electrical potential between the workpiece and counter-electrode, and the production of plasma (micro-arc discharges on the workpiece surface). The plasma micro-arcs provide a heat source for surface modification via localized surface melting and rapid cooling (cleaning process) and, if desirable, enhance ion deposition on a given substrate (coating). Three substrates (low carbon steel, pure Al and pure Ti) were "cleaned" by EPP and their near surface layer microstructure was studied. It was found that the …
Bubble Template Synthesis Of Hollow Gold Nanoparticles And Their Applications As Theranostic Agents, Chienwen Huang
Bubble Template Synthesis Of Hollow Gold Nanoparticles And Their Applications As Theranostic Agents, Chienwen Huang
Material Science and Engineering Dissertations - Archive
Hollow gold nanoparticle with a sub-30nm polycrystalline shell and a 50 nm hollow core has been successfully synthesized through the reduction of sodium gold sulfite by electrochemically evolved hydrogen. Such hollow gold nanoparticles exhibit unique plasmonic properties. They strongly scatter and absorb near infrared light. In this thesis we seek to understand the formation mechanism of hollow gold nanoparticles in this new synthesis process and their plasmonic properties. Also, we explore their biomedical applications as theranostic agents (therapeutic and diagnostic imaging). A lithographically patterned electrode consisting of Ag stripes on a glass substrate was used to investigate the formation process …
Study On The Leakage Current Behavior And Conduction Mechanism Of Porous Low-K In Cu/Porous Low-K Interconnects: The Influence Of Extrinsic Factors, Liangshan Chen
Material Science and Engineering Dissertations - Archive
This study investigates the influence of extrinsic factors including moisture and impurities trapped in porous low-k (PLK) and defective diffusion barrier on the leakage current behavior and the associated conduction mechanism of PLK in advanced Cu/PLK interconnects. For this purpose, a voltammetry technique that was previously developed for diffusion barrier characterization was extended to detect the trapped impurities in PLK. With this technique in hand, the influence of extrinsic factors was then studied. Cu was found to diffuse out into PLK through barrier defects in the presence of electric stress. Its out-diffusion and subsequent migration in PLK manifested as a …
Nanocrystalline Piezoresistive Polysilicon Film Obtained By Aluminum Induced Crystallization For Pressure Sensing Applications, Suraj Kumar Patil
Nanocrystalline Piezoresistive Polysilicon Film Obtained By Aluminum Induced Crystallization For Pressure Sensing Applications, Suraj Kumar Patil
Material Science and Engineering Dissertations - Archive
The overall objective of our research was to integrate various sensors on to a single flexible substrate for multi-sensory information gathering. Additional capabilities could be incorporated towards the realization of 'smart skin' for simultaneous and real time sensing of various mechanical, biological and chemical stimuli. Recent research venues are dictated by the trend of shifting from conventional silicon (Si) substrates to lower weight, low profile, structurally robust and lower cost flexible substrates. These flexible substrates easily conform to non-planar objects, could be batch fabricated at lower cost and enable multilayer construction. This would eventually evolve into seamless assimilation of sensors …
Po2 Dependant Resistance Switch Effect In Highly Epitaxial (Laba)Co2o5+[Delta] Thin Films, Jian Liu, Gregory Collins, Ming Liu, C L. Chen, Jiechao Jiang, Efsftathios Meletis, Qingyu Zhang, Chuang Dong
Po2 Dependant Resistance Switch Effect In Highly Epitaxial (Laba)Co2o5+[Delta] Thin Films, Jian Liu, Gregory Collins, Ming Liu, C L. Chen, Jiechao Jiang, Efsftathios Meletis, Qingyu Zhang, Chuang Dong
Material Science and Engineering Faculty Publications - Archive
Giant resistance switching behavior in mixed conductive LaBaCo2O5+ epitaxial thin film were discovered in high temperature and reducing environments during the reduction and reoxidation process. A reproducible resistance response of over 99% was achieved in the films during a change of 4% H2 /96% N2 to oxygen at temperature range of 400– 780 °C. The results indicate that at, low oxygen partial pressure, the extension of oxygen deficiency is an essential factor to the high temperature physical properties of LaBaCo2O5+ and demonstrates its potential application as a chemical sensor device for reducing environments at high temperature. © 2010 American Institute …
A Study Of Diamond Nanoparticles, Rajarshi Chakraborty
A Study Of Diamond Nanoparticles, Rajarshi Chakraborty
Material Science and Engineering Theses - Archive
Diamond nanoparticles grown previously by Hot Filament Assisted Chemical Vapor Deposition have been characterized by utilizing Atomic Force Microscopy, Scanning Electron Microscopy, Raman Spectroscopy and X Ray Diffraction. AFM and SEM data shows increase in nanoparticle size with growth period ranging from about 20 nm for 15 minutes to 200 nm for 105 minutes growth. Raman spectra have been analyzed by using optical phonon confinement in nanometer size crystals. Based on the SEM, Raman spectroscopy and XRD data, we present clear evidence for nanometer size (10-200 nm) diamond particles in CVD-grown diamond thin films.
Development Of Amphiphilic Biodegradable Photoluminescent Polymers, Shengyuan Zhou
Development Of Amphiphilic Biodegradable Photoluminescent Polymers, Shengyuan Zhou
Material Science and Engineering Theses - Archive
The development of amphiphilc block copolymers have been attracted much attention due to their potential use in drug delivery and targeting. Less research work focused on their prospective application as fluorescent imaging probes. Although some research reported fluorescent materials encapsulated in amphiphilc micelles has provided significant opportunities for biological labeling and imaging in biomedical fields, these fluorescent materials, such as organic dyes and quantum dots, suffer from photobleaching, cytotoxicity and lack of biodegradability. A novel and ideal amphiphilic biodegradable photoluminescent polymeric micelle was developed, which will open new avenues for biomedical filed. The objective of this reseach was to develop …
Synthesis And Characterization Of Platinum And Carbon Nanoparticle In Benzene By Electric Plasma Discharge In Ultrasonic Cavitation, Rakesh Pratapbhai Chaudhary
Synthesis And Characterization Of Platinum And Carbon Nanoparticle In Benzene By Electric Plasma Discharge In Ultrasonic Cavitation, Rakesh Pratapbhai Chaudhary
Material Science and Engineering Theses - Archive
Nanoparticles are of interest due to the high number of atoms located on the surface. This high surface area is conductive to higher catalytic efficiency than normal seen in bulk metals. Of numerous Nanoparticles catalysts studied, Platinum (Pt) nanoparticles have attracted particular interest due to their superior catalysis for many chemical reactions, especially for fuel cell reactions including hydrogen oxidation and oxygen reduction. Carbon supported Pt nanoparticles are active anode catalysts for fuel cells. In this thesis nano-sized Pt particles have been synthesized by an advanced and cost effective method. Pt nanoparticles embedded in carbon matrix were synthesized by an …
Nanoparticle Bridge Dna Biosensor, Hong-Wen Huang
Nanoparticle Bridge Dna Biosensor, Hong-Wen Huang
Material Science and Engineering Dissertations - Archive
A new DNA sensing method is demonstrated in which DNA hybridization events lead to the formation of nanoparticle satellites that bridge two electrodes and are detected electrically. The hybridization events are exclusively carried out only on specific locations, the surfaces of C-ssDNA modified 50 nm GNPs. The uniqueness of this work is that only a small number of T-ccDNA molecules (<10) is required to form the nanoparticle satellites, allowing ultra-sensitive DNA sensing. The principle of this new DNA sensing technique has been demonstrated using target DNA and three-base-pair-mismatched DNA in 20nM concentrations. Three single-stranded DNA (ssDNA) system is used in our experiment which includes Capture-ssDNA (C-ssDNA), Target-ssDNA (T-ssDNA) and Probe-ssDNA (P-ssDNA). Both C-ssDNA and P-ssDNA are modified by a thiol group and can hybridize with different portions of T-ssDNA. T-ssDNA requires no modification in three ssDNA system, which is beneficial in many applications. C-ssDNA modified 50nm gold nanoparticle (C-50au) and P-ssDNA modified 30nm gold nanoparticle (P-30au) are prepared through the reaction of thiol-gold chemical bonding between thiolated ssDNA and gold nanoparticle (GNP) (C-ssDNA with 50nm GNP, P-ssDNA with 30nm GNP). We controllably place the C-50au only on the SiO2 band surface (~ 90nm width) between two gold electrodes (source and drain electrodes) by forming positively- and negatively-charged self-assembled monolayers (SAMs) on SiO2 and gold surface, respectively. DNA modified GNP is negatively charged due to ionization of phosphate group on DNA back bone. C-50au therefore is negatively charged and can only be attracted toward SiO2 area (repelled by negatively charged gold electrode surface). The amine group of positively-charged SAMs on SiO2 surface is then passivated by converting to non-polar methyl functional group after C-50au placement. P-30au is first hybridized with T-ssDNA in the solution phase (T-P-30au formed) and is introduced into DNA detection device in which C-50au are immobilized on ~90nm width SiO2 band (between two gold electrodes). The passivation step ensures every T-P-30au are attached only to C-50au through hybridization (T-P-30au will not be attracted toward SiO2 surface or gold electrodes). GNP bridges are formed across the electrodes and provide an electrical path between two gold electrodes.We ensure that every T-P-30au only hybridizes on the surface of C-50au by (1) accurately controlling C-50au placement between two gold electrodes, (2) passivating positively-charged SAMs on SiO2 surface after C-50au immobilization. When T-P-30au hybridize with C-50au on ~90nm wide SiO2 surface, GNP bridges form and provide an electrical path between two gold electrodes even with only a few hybridization events. Experimental results show that even a few GNP bridges formed on SiO2 band can provide a significant conductance change from an open circuit to a conductive circuit (current = 0.5 uA at voltage = 0.1 V with four GNP bridge). We also used 3-base-pair-mismatched ssDNA (3mm-ssDNA) as a control experiment, which always resulted in an open circuit (no GNP bridge formed). Our detection device is compatible with current CMOS fabrication technology and can be manufactured on a wafer scale. The direct electrical output of this DNA detection technique provides a promising basis for high-throughput screening (can be fabricated on a wafer scale) with no expensive equipment required.
Measurement Of The Spectral Distribution Of Low Energy Electrons Emitted As A Result Of Nvv Auger Transitions In Ag (100), Sushant Kalaskar
Measurement Of The Spectral Distribution Of Low Energy Electrons Emitted As A Result Of Nvv Auger Transitions In Ag (100), Sushant Kalaskar
Material Science and Engineering Theses - Archive
Auger Photoelectron Coincidence Spectroscopy (APECS) was used to investigate the physics of the Low Energy Tail (LET) of the Auger spectrum of Ag (100) at the National Synchrotron Light Source, Brookhaven National Lab, New York. The incident photon energy was set at 180eV. The spectrum shows a peak due to the NVV Auger transition accompanied by a substantial low energy region. The APECS spectrum contains the contributions from electrons excited by the NVV Auger transition plus a background due to true coincidences between photoemitted valence band electrons that undergo inelastic scattering and transfer part of their energy with other valence …
Formation Of Au Nanoparticles Through Reaction Of Na₃Au(So₃)₂ By Electrochemically Evolved Hydrogen, Yi Jiun Li
Formation Of Au Nanoparticles Through Reaction Of Na₃Au(So₃)₂ By Electrochemically Evolved Hydrogen, Yi Jiun Li
Material Science and Engineering Theses - Archive
Hydrogen evolution during electrochemical deposition has long been regarded as undesired and deliberately suppressed since small hydrogen bubbles could cause a rough surface of deposits. Here, we demonstrate a new role for electrochemically evolved hydrogen, serving as both templates and reducing agents for synthesizing Au nanoparticles via electroless depositions from Na₃Au(SO₃)₂ electrolytes. A series of experiments have been designed to investigate this new role. A working electrode of patterned Ag strips on the non-conductive substrates has been used. It has been observed that when a potential more negative than hydrogen evolution potential was applied to metal areas, a large amount …
Self-Assembly Of Polystyrene Nanospheres And Its Applications As Templates For Plasmonic Structures, Shih-Hsin Chang
Self-Assembly Of Polystyrene Nanospheres And Its Applications As Templates For Plasmonic Structures, Shih-Hsin Chang
Material Science and Engineering Dissertations - Archive
Monodispersed colloidal polystyrene spheres have been self-assembled into various structures as templates for the fabrication of different nanostructures. Two unique self-assembly processes have been developed and systematically investigated. A method to make the multi-layer and mono-layer close-packed structure by means of capillary-convective force has been developed. By directly visualizing the self-assembling process using optical microscopy, a mechanism based on the 2-D crystal formation and 3-D repulsive force model has been proposed to explain the process. A vertical deposition technique to produce nanosphere crystal structure with single orientation on hydrophilic glass substrate has also been developed. Using a lithographically patterned substrate …
A Study On The Corrosion Behavior Of Nanocrystalline Nickel In Aqueous Environments, Anjana Shyam Sundar
A Study On The Corrosion Behavior Of Nanocrystalline Nickel In Aqueous Environments, Anjana Shyam Sundar
Material Science and Engineering Theses - Archive
Nanocrystalline materials possess considerably enhanced properties arising from their small grain size. Significant interest has been paid in the past to their mechanical and physical properties. Very little attention has been attracted by their electrochemical behavior, which is expected to be affected by the significant volume fraction of grain boundaries. In the present study, corrosion experiments were conducted in nanocrystalline nickel in two entirely different solutions in order to obtain a better understanding of its corrosion behavior. This is of particular interest to MEMS and NEMS devices where electroplated nanocrystalline nickel is the metal of choice. The corrosion behavior of …
Synthesis And Characterization Of Ferromagnetic Nanowires, Poching Tsai
Synthesis And Characterization Of Ferromagnetic Nanowires, Poching Tsai
Material Science and Engineering Theses - Archive
Ferromagnetic nanocrystals with shape anisotropy have drawn great attention in the past decades because of their unique magnetic properties and for their potential applications in ultra-high-density magnetic recording media, exchange-coupled nanocomposite magnets and related nanodevices. In this thesis, synthesis and characterixation of ferromagnetic CoNi and CoFe nanowires are reported. CoNi nanocrystals with different size, shape and composition were successfully synthesized via a catalyst chemical solution method. It was found out that the structure and morphology can be controlled by altering the NaOH concentration, and the elongation of the nanowires can be adjusted by changing surfactants ratio and catalyst amount. Unlike …
Solid-State Tunneling Spectroscopy Of Individual Quantum Dots, Ramkumar Subramanian
Solid-State Tunneling Spectroscopy Of Individual Quantum Dots, Ramkumar Subramanian
Material Science and Engineering Dissertations - Archive
Quantum dots are gaining importance for their potential applications in the fields of energy harvesting, bio-labeling and treatment, in opto-electronic devices and in photonic devices. For all these applications, it is imperative to know their electronic structure. Although currently several spectroscopic techniques exist to study the electronic structure of these quantum dots, they are accompanied by other effects and do not give purely the electronic structure of the individual quantum dot. The main goals of this research are to:o To study the energy level structure of `single' quantum dots.o Develop a new spectroscopic technique that allows the measurement of the …
Transmission Electron Microscopy Studies Of Lamno₃ And La₁₋Xsrxmno₃Thin Films Grown On Various Substrates, Yinsheng Fang
Transmission Electron Microscopy Studies Of Lamno₃ And La₁₋Xsrxmno₃Thin Films Grown On Various Substrates, Yinsheng Fang
Material Science and Engineering Theses - Archive
LaMnO₃ (LMO) and La₁₋xSrxMnO₃ (LSMO) thin films with colossal magnetoresistance have attracted considerable interest for potential applications in many technological devices, such as magnetic sensors and read-head of computer memory. In this work, polycrystalline and epitaxial LMO and LSMO thin films were deposited on various substrates including (001) Si, (001) MgO, and (001) LaAlO₃ (LAO) using RF magnetron sputtering. The microstructures of the thin films were initially studied using X-ray diffraction. Detailed microstructure information such as crystallite of the films, grain size, epitaxial quality, crystallographic structure and film/substrate interface were studied using high-resolution transmission electron microscope (HRTEM). More specifically, Effects …
Synthesis And Evaluation Of Bioceramics For Orthopedics And Tissue Culture Applications, Hande Demirkiran
Synthesis And Evaluation Of Bioceramics For Orthopedics And Tissue Culture Applications, Hande Demirkiran
Material Science and Engineering Dissertations - Archive
Hydroxyapatite is the most well known phosphate in the biologically active phosphate ceramic family by virtue of its similarity to natural bone mineral. Among all bioglass compositions Bioglass®45S5 is one of the most bioactive glasses. This study initially started by adding different amounts (1, 2.5, 5, 10, and 25 wt. %) of Bioglass®45S5 to synthetic hydroxyapatite in order to improve the bioactivity of these bioceramics.The chemistries formed by sintering and their effect on different material properties including bioactivity were identified by using various techniques, such as powder and thin film x-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray …
Tribological Performance Of Ashless Antiwear Additives Under Extreme Pressure Conditions, Bohoon Kim
Tribological Performance Of Ashless Antiwear Additives Under Extreme Pressure Conditions, Bohoon Kim
Material Science and Engineering Dissertations - Archive
Zinc diakyl dithiophosphate (ZDDP) has been used in engine oil for several decades as an antiwear additive. However, ZDDP is the primary source of P, S and Zn in the exhaust, which results in frequent maintenance or replacement of exhaust gas treatment systems. The use of ashless additives is more desirable because of recent environmental regulations. The main goal of this research was to develop a fundamental understanding of how ashless compounds protect the tribological surface in comparison to ZDDP. X-ray absorption near edge structure spectroscopy (XANES) has been performed on tribo and thermal films in order to investigate the …
Self Powered Sensing By Combining Novel Sensor Architectures With Energy Harvesting, Vishwas Bedekar
Self Powered Sensing By Combining Novel Sensor Architectures With Energy Harvesting, Vishwas Bedekar
Material Science and Engineering Dissertations - Archive
Recent advancements in the field of wireless sensor networks have resulted in increasing demand for self-powering techniques that reduces the dependence on batteries. In order to address this problem, there has been significant effort on generating small electrical power locally by harvesting energy from freely available environmental sources such as mechanical vibrations, wind, and stray magnetic field. Further, there is need for inventing new sensing techniques to reduce the overall power consumption. The road for reaching the destination of self-powered sensor networks requires cooperative progress in reduction in sensor power consumption by developing new sensing mechanisms and local generation of …
Synthesis, Characterization And Potential Applications Of Fept Nanoparticles, Vikas Nandwana
Synthesis, Characterization And Potential Applications Of Fept Nanoparticles, Vikas Nandwana
Material Science and Engineering Dissertations - Archive
Monodisperse FePt nanoparticles with controlled size and geometry have drawn great attention in the last decade for fundamental scientific studies and for their potential applications in advanced materials and devices such as ultra-high-density magnetic recording media, exchange-coupled nanocomposite magnets, biomedicines and nanodevices. This dissertation focuses on the synthesis and characterization of FePt nanoparticles and their use in potential applications. The FePt nanoparticles of different size (2 to 16 nm) and shape (spherical, cubic, rod) were synthesized by a chemical solution method. The size and shape of these particles were controlled by adjusting reaction parameters. The as-synthesized FePt nanoparticles have chemically …
Synthesis And Dip-Pen Nanolithographical Patterning Of Ferrite Nanoparticles, Jingwen He
Synthesis And Dip-Pen Nanolithographical Patterning Of Ferrite Nanoparticles, Jingwen He
Material Science and Engineering Theses - Archive
Magnetic nanoparticles are of great interest for researchers from a wide range of disciplines, including magnetic fluids, catalysis, biotechnology/biomedicine, magnetic resonance imaging, data storage, and environmental remediation. Ferrites, a class of ferrimagnetic ceramic compounds with the chemical formula of MFe₂O₄, where M represents any one of several metallic elements such as Mg, Fe, Co, Ni, Cu and so on, are commonly used magnetic materials for nanoparticles. Magnetite (Fe3O₄) is the prototype of ferrites. Magnetite nanoparticles have been prepared through the co-precipitation of Fe²⁺ and Fe³⁺ aqueous salt solutions by addition of base. They exhibit a size distribution from 4 nm …
Synthesis And Tribological Properties Of Dlc Film By Rf Pacvd: Effect Of Processing Parameters, Pruthul Desai
Synthesis And Tribological Properties Of Dlc Film By Rf Pacvd: Effect Of Processing Parameters, Pruthul Desai
Material Science and Engineering Theses - Archive
Diamond-like carbon (DLC) films, have gained grounds in many industries ranging from automobile and oil and gas to electronics and bio fields due to their low friction and wear rate, chemical inertness and high hardness. Radio Frequency (RF) plasma discharge has been widely used to produce amorphous carbon films, because this method can be applied not only for etching but also for deposition on insulators. The advantage of RF plasma discharge is the application for wide area and the stability as compared with direct current (DC) plasma. The properties of DLC films deposited by RF plasma-assisted chemical vapor deposition (PACVD) …
Tribological Behavior Of Nanocrystalline Metals Prepared By Surface Mechanical Attrition Treatment, Michael Frink
Tribological Behavior Of Nanocrystalline Metals Prepared By Surface Mechanical Attrition Treatment, Michael Frink
Material Science and Engineering Theses - Archive
Nanocrystalline materials have shown great promise for a number of engineering applications ranging from structural and electronics to biomaterials and drug delivery. Nanoscale grain structures can cause tremendous improvements in strength, hardness and other mechanical properties. This is partially due to the suppression of dislocations within nanocrystalline grains and the entirely different deformation modes active at that scale. In spite of anticipated benefits, very little work has been performed to explore nanoscale effects on the tribological behavior of materials. Surface Mechanical Attrition Treatment (SMAT) is an effective and economical method to produce nanostructured surface layers in bulk materials. The process …
Thioacetamide As A Sulfur Precursor For Chalcopyrite Thin Film Solar Cells, Alex Alphonse
Thioacetamide As A Sulfur Precursor For Chalcopyrite Thin Film Solar Cells, Alex Alphonse
Material Science and Engineering Theses - Archive
Chalcopyrite CuInS₂ (CIS) thin films have the potential to be used in low cost terrestrial photovoltaic applications. The band gap of CIS is around 1.5 eV [1] and it well matches with the solar spectrum. However, the power conversion efficiencies in CIS solar cells are presently limited to 13.2% [2]. CIS absorber layers can be produced in a simple two-stage process consisting of the physical vapor deposition of a Cu-In bilayer - generally with Cu-rich composition - and its subsequent sulfurization under sulfur atmosphere made by either sulfur vapor or H₂S. While sulfur vapor is a safer option than H₂S …
Effect Of Reflow Variables On The Nanoscale Mechanical Properties Of Lead Free Solders, Tonye Adeogba
Effect Of Reflow Variables On The Nanoscale Mechanical Properties Of Lead Free Solders, Tonye Adeogba
Material Science and Engineering Theses - Archive
This study presents findings on the nano-mechanical properties of binary and ternary (Cu, Ag) - Sn Solders. Nanoindentation with a cube corner tip was used on Sn-Ag and SAC405 alloy compositions to investigate the effect of reflow process variables on the properties of hardness and reduced modulus on a nanoscale. The specimens tested were sandwich solder joints where Cu was the substrate. While the reflow variables of cooling rate and reflow time were found to cause changes in IMC morphology and solder matrix microstructure, the nano hardness and reduced modulus were independent of these variables. Low max loads coupled with …
Negative Differential Resistance In Hydrated Deoxyribonucleic Acid Thin Films Mediated By Diffusion-Limited Redox Reaction, Hou Kuan Lee
Negative Differential Resistance In Hydrated Deoxyribonucleic Acid Thin Films Mediated By Diffusion-Limited Redox Reaction, Hou Kuan Lee
Material Science and Engineering Theses - Archive
The charge transport mechanisms in DNA proposed in the literature cover broad range of possibilities including molecular band conduction, superexchange, multistep hole hopping, and polaron hopping. The reason for the surprisingly diverse results is all the variables in the experiments - DNA sequence, DNA characteristic (single molecule or bundle, DNA length), the metal/DNA contacts, and the environmental dissimilarities in temperature, humidity, etc. In this study, the humidity effect on the electrical conduction in DNA was systematically investigated in a humidity chamber over the wide range of DC voltage. The exponential increase in conduction with increasing humidity was observed for the …
Mechanism Of Wear Protection Of Al-Alloys Using Xanes, Beibei Wang
Mechanism Of Wear Protection Of Al-Alloys Using Xanes, Beibei Wang
Material Science and Engineering Theses - Archive
The mechanism of wear protection of Al-Si alloys in wear tests using lubricants containing Zinc dialkyl-dithiophosphate (ZDDP), Dialkyl dithiophosphate (DDP) , Amine phosphates, Thiadiazole, Antimony 0, 0-dialkylphosphorodithioate (SbDDP) was studied. Using techniques such as XANES this study examined the tribological behavior of these compounds and the characteristics of the tribofilms formed by them. High frequency reciprocating rig (HFRB) tests were conducted with lubricant containing these five antiwear additives were compared in both base oil and fully formulated oil. The tribofilms formed were then analyzed by a variety of techniques such as Scanning electron microscopy of the film and the composition …
Synergistic And Antagonistic Effect Of Sulfur-Based Additives On The Performance Of Greases With Zddp And Ptfe, Arunya Suresh
Synergistic And Antagonistic Effect Of Sulfur-Based Additives On The Performance Of Greases With Zddp And Ptfe, Arunya Suresh
Material Science and Engineering Theses - Archive
Lithium-base greases constitute about 50% of the grease market. The current trend is towards developing greases with longer working life and wider application flexibility. To address this concern, greases are blended with antiwear and extreme pressure (EP) additives that serve to reduce wear and increase the operating life of the machinery by creating a low strength, shearable film on the moving surfaces. In the current study, greases were developed to address the need for both performance as prescribed by the ASTM standards D2266 and D2596, respectively. The actual bearing conditions vary significantly with load, rpm and duration of test. These …
Corrosion And Leaching Study Of Low Copper (I) Oxide Paints For Antifouling Application, Hansika Parekh
Corrosion And Leaching Study Of Low Copper (I) Oxide Paints For Antifouling Application, Hansika Parekh
Material Science and Engineering Theses - Archive
Global environmental concern/economy challenges necessitate innovation of AFP's with novel additives offering improved corrosion protection, and biofouling resistance. Dispersing large proportions (40-70%) of Cu/Cu2O in paints although inexpensive produces excessive leaching & heavy accumulation of copper in marine. This study aims at formulating AFP's with reduced Cu2O levels along with novel additives, targeting controlled copper release around 15 ug/cm2/day. In the present study several formulations were prepared using Viscoplex (PAMA in mineral oil), Ionomer ED-SPAN and CuDDP. Substitute ocean water was prepared to simulate marine environmental conditions and perform leaching studies of different formulations. A variety of preliminary elimination tests …