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Optical Characterization Of Electrochemically Self-Assembled Compound Semiconductor Nanowires, Sivakumar Ramanathan Jan 2006

Optical Characterization Of Electrochemically Self-Assembled Compound Semiconductor Nanowires, Sivakumar Ramanathan

Theses and Dissertations

Semiconductor nanowires have attracted considerable attention as possible source for lasers and optical storage media. We report the fabrication and optical characterization of ZnO and CdS nanowires. The former are produced by electrochemical deposition of Zn inside nanoporous alumina films containing regimented arrays of 10nm, 25nm and 50 nm diameter pores, followed by room temperature chemical oxidization. Fluorescence spectroscopy shows different characteristics associated with different sample diameter. The 50 nm ZnO nanowires show an exciton recombination peak and an additional peak related to the deep trap levels. 25 nm ZnO nanowires show a only the exciton recombination peak, which is …


Green Organic Solar Cells From A Water Soluble Polymer And Nancrystalline Tio2, Qiquan Qiao Jan 2006

Green Organic Solar Cells From A Water Soluble Polymer And Nancrystalline Tio2, Qiquan Qiao

Theses and Dissertations

The cost of the present generation of inorganic silicon solar cells is very high and further breakthroughs in cost and efficiency using traditional materials are becoming less and less likely after over 50 years of development. Next generation organic solar cells offer a solution to the limitations of silicon through the vision of low-cost, liquid-based, large area fabrication technology based on polymer and nanomaterials at room temperature. However, most polymers used in solar cells are dissolved in organic solvents such as xylene, toluene, chloroform, and chlorobenzene. Such solvents are harmful to people and environments, leading to higher costs due to …


Experimental Study Of The Entrainment Of Nanoparticles From Surfaces, Srirupa Ganguly Jan 2006

Experimental Study Of The Entrainment Of Nanoparticles From Surfaces, Srirupa Ganguly

Theses and Dissertations

The adhesion and resuspension of nanoparticles is important in applications ranging from semiconductor manufacturing to pollution management. The objective of this work is to understand the effect of particle size on re-entrainment of nanometer scale particles. One of the major contributions is to reduce the randomness introduced in past measurements on resuspension by controlling humidity, temperature, material and the distribution of shape and particle sizes. In the process of studying particle size, the effect of surface roughness was also found. Measurements of the detachment fraction of carbon particles as a function of flow rate show three distinct regimes that we …


Accelerating Whole-Cell Biocatalysis By Enhancing Outer Membrane Permeability, Ye Ni Jan 2006

Accelerating Whole-Cell Biocatalysis By Enhancing Outer Membrane Permeability, Ye Ni

Theses and Dissertations

Whole-cell biocatalysts are preferred in many biocatalysis applications. However, cell envelope often represents a formidable permeability barrier. As a result, reactions catalyzed by whole-cells are reportedly orders of magnitude slower than those of by their free enzyme counterparts. The present research addresses this critical issue by using membrane engineering approaches. Two E. coli strains with genetically altered outer membrane structures were used in the study, a lipopolysaccarides (LPS) mutant SM101 and a Braun's lipoprotein mutant E609L. The effects of outer membrane mutation on the permeability of substrates differing substantially in size and hydrophobicity were investigated by combining the mutant cells …


Spin Polarized Transport In Nanoscale Devices, Sandipan Pramanik Jan 2006

Spin Polarized Transport In Nanoscale Devices, Sandipan Pramanik

Theses and Dissertations

The ultimate goal in the rapidly burgeoning field of spintronics is to realize semiconductor-based devices that utilize the spin degree of freedom of a single charge carrier (electron or hole) or an ensemble of such carriers to achieve novel and/or enhanced device functionalities such as spin based light emitting devices, spin transistors and femto-Tesla magnetic field sensors. These devices share a common feature: they all rely on controlled transport of spins in semiconductors. A prototypical spintronic device has a transistor-like configuration in which a semiconducting channel is sandwiched between two contacts (source and drain) with a gate electrode sitting on …


Determination Of The Mechanical Properties Of Electrospun Gelatin Based On Polymer Concentration And Fiber Alignment, Leander Taylor Iii Jan 2006

Determination Of The Mechanical Properties Of Electrospun Gelatin Based On Polymer Concentration And Fiber Alignment, Leander Taylor Iii

Theses and Dissertations

The process of electrospinning has given the field of tissue engineering insight into many aspects of tissue engineered scaffolds, including how factors such as fiber diameter and porosity are affected by polymer concentration. However, the affects of fiber alignment upon the material properties of electrospun scaffolds remains unclear. The purpose of this study is to determine how the material properties of electrospun gelatin scaffolds are affected by changes in fiber alignment and starting gelatin concentration. Gelatin scaffolds, with starting concentrations of 80, 100, and 130mg/m1, were electrospun onto a target mandrel rotating at various speeds. Samples of each scaffold were …


Scaffold Permeability As A Means To Determine Fiber Diameter And Pore Size Of Electrospun Fibrinogen, Scott Allen Sell Jan 2006

Scaffold Permeability As A Means To Determine Fiber Diameter And Pore Size Of Electrospun Fibrinogen, Scott Allen Sell

Theses and Dissertations

The purpose of this study was to construct a flowmeter that could accurately measure the hydraulic permeability of electrospun fibrinogen scaffolds, providing insight into the transport properties of electrospun scaffolds while making the measurement of their topographical features (fiber and pore size) more accurate. Three different concentrations of fibrinogen were used (100, 120, and 150mg/ml) to create scaffolds with three different fiber diameters and pore sizes. The fiber diameters and pore sizes of the electrospun scaffolds were analyzed through scanning electron microscopy and image analysis software. The permeability of each scaffold was measured and used to calculate permeability-based fiber diameters …


Evaluation Of Prototype Cell Delivery Catheters Using Agarose Gel And Cell Culture Experiments, Sagar Panse Jan 2006

Evaluation Of Prototype Cell Delivery Catheters Using Agarose Gel And Cell Culture Experiments, Sagar Panse

Theses and Dissertations

Neurodegenerative diseases and brain tumors affect millions of patients worldwide and are associated with significant morbidity and mortality. The blood brain barrier constitutes a major obstacle to delivery of therapeutic agents administered systemically for treating these disorders. Intracranial drug delivery provides a novel way of bypassing the blood brain barrier and achieving high concentration of therapeutic agents in the brain while avoiding systemic side effects. However damage to tissues during insertion of catheters, release of air in the brain and consequent backtracking of dye are some disadvantages with this mode of treatment. We evaluated prototype cell delivery catheters (each with …


A Computational Study Of Axial Compressor Rotor Casing Treatments And Stator Land Seals, Charles C. Cates Jan 2006

A Computational Study Of Axial Compressor Rotor Casing Treatments And Stator Land Seals, Charles C. Cates

Theses and Dissertations

As fuel prices soar ever higher, aircraft manufacturers and their airline customers demand that the next generation of engines used on their aircraft push the limits of efficiency and capability. This study consists of a computational examination of two currently accepted methods of axial compressor performance improvement in terms of surge margin and efficiency, rotor casing treatments and stator land seals.ADPAC and Fluent CFD solvers were used in the analysis of circumferential groove casing treatments and two types of stator seals, one typical of a front stage stator and one typical of a rear stage stator. The computational solutions and …


Hmg-Coa Reductase Inhibitors Act Synergistically With Ucn-01 Through Ras Inhibition, Payal Khanna Jan 2006

Hmg-Coa Reductase Inhibitors Act Synergistically With Ucn-01 Through Ras Inhibition, Payal Khanna

Theses and Dissertations

The primary objective of this study is to elucidate the mechanism by which the reagent UCN-01 induces apoptosis when administered to leukemia cells along with HmG-CoA reductase inhibitors, mainly the statins. In this study, we demonstrated that exposure of leukemia cell lines to lovastatin (20 uM, 18 hours) and UCN-01 (100 nM, 18 hours) resulted in mitochondria dysfunction, procaspase 3 and 9 cleavage, and PAW degradation along with marked cytochrome C release and apoptosis. Although similar molecular mechanisms have not yet been confirmed in other cancers, our hypothesis holds that enhanced apoptotic effects of UCN-01 are due in part to …


Design And Validation Of A Full Contact Gait Simulator For The Cadaveric Lower Extremity, Joseph Michael Iaquinto Jan 2006

Design And Validation Of A Full Contact Gait Simulator For The Cadaveric Lower Extremity, Joseph Michael Iaquinto

Theses and Dissertations

The projects goal was to create a device to simulate full contact gait in the cadaveric lower extremity. The Contact Gait Simulation System loads specific muscles to recreate anatomical dorsi and plantar flexion of the ankle under axial loading. A system of pneumatic load generation was connected a LabVIEW virtual instrument (VI), which controlled the application of these loads. The loads were roughly based off literature cited EMG data, and further modified from feedback. In addition to controlling the load system, the VI also coordinates external sensor timing. Along with this simulator, software was developed specifically for analyzing pressure data …


Development Of A Software Application To Extract The Features Of Normal Respiratory Sounds From The Lungs And The Trachea, Ranjani Sabarinathan Jan 2006

Development Of A Software Application To Extract The Features Of Normal Respiratory Sounds From The Lungs And The Trachea, Ranjani Sabarinathan

Theses and Dissertations

Auscultation has been widely regarded as one of the most important noninvasive diagnostic tools for clinical diagnosis of the respiratory tract. The purpose of this thesis was to develop a software application capable of extracting the key features of respiratory sound signals from the lungs and trachea of healthy persons. The efficacy of the program was evaluated by the verification of the important features of the sound signals from the left and right lungs and the trachea such as 1) right and left lung symmetry and 2) dissimilarity between the trachea and both lungs. The program was developed in LabView …


The Effect Of Stationary Uv Excitation On The Optical Behavior Of Electrochemically Self-Assembled Semiconductor Nanowires, Rajesh A. Katkar Jan 2006

The Effect Of Stationary Uv Excitation On The Optical Behavior Of Electrochemically Self-Assembled Semiconductor Nanowires, Rajesh A. Katkar

Theses and Dissertations

In this work, we investigate the optical response of the semiconductor quantum wire array when excited by stationary UV light. The array is synthesized by selectively electro-depositing the semiconductor material in electrochemically self-assembled porous alumina templates. Our studies are based on the optical behavioral changes in CdS, ZnO, ZnSe and CdSe quantum wires of 50-, 25- and 10-nm diameters. We use a set of generalized Bloch equations to solve the interband polarization function of the semiconductors derived within the Hartree-Fock approximation, and theoretically model the UV excitation effect on the quantum wires. The solutions which consider the effects of screening, …


A Wireless Surface Electromyography (Wsemg) System, Aleeta E. Bell Jan 2006

A Wireless Surface Electromyography (Wsemg) System, Aleeta E. Bell

Theses and Dissertations

Surface Electromyography (SEMG) systems are utilized throughout the medical industry to study abnormal electrical activity of the human muscle. Historically, SEMG systems employ surface (skin) mounted sensors that transmit electrical muscle data to a computer base via an umbilical cord. A typical SEMG analysis may exercise multiple sensors, each representing a unique data channel, positioned about the patient's body. Data transmission cables are linked between the surface mounted sensor nodes and a backpack worn by the patient. As the number of sensors increases, the patient's freedom of mobility decreases due to the lengthy data cables linked between the surface sensors …


Computational Modeling To Predict Mechanical Function Of Joints: Validations And Applications Of Lower Leg Simulations, Peter C. Liacouras Jan 2006

Computational Modeling To Predict Mechanical Function Of Joints: Validations And Applications Of Lower Leg Simulations, Peter C. Liacouras

Theses and Dissertations

Computational models of musculoskeletal joints and limbs can provide useful information about joint mechanics. Validated models can be used as a predictive device for understanding joint function and serve as a clinical tool for predicting the outcome of surgical procedures. A new computational modeling approach was developed for simulating joint kinematics that are dictated by bone/joint anatomy, ligamentous constraints, and applied loading.Three-dimensional computational models of the lower leg were created. Model development involved generating three-dimensional surfaces from CT images, followed by importing these surfaces into SolidWorks and COSMOSMotion. ThroughSolidWorks and COSMOSMotion, each bone surface was created into a solid object …


Detection, Identification And Classification Of Suck, Swallow And Breathing Activity In Premature Infants During Bottle-Feeding, Fedra Adnani Jan 2006

Detection, Identification And Classification Of Suck, Swallow And Breathing Activity In Premature Infants During Bottle-Feeding, Fedra Adnani

Theses and Dissertations

Prematurity, especially if extreme, is one of the leading causes of problems and/or death after delivery. Among all the problems encountered by premature infants, feeding difficulties are very common. Many premature infants are fed intravenously at first, and they progress to milk feedings provided by a tube passed into the stomach. At around 34 weeks of gestation, premature infants should be able to breastfeed or take a bottle. At the same time such premature infants are usually faced with difficulty making the transition from tube-feeding to full oral feeding. In this study three physiological measurements of premature infants including sucking, …