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Production And Characterization Of Composite Nano/Micro Sized Particles By Rapid Expansion Of Supercritical Solutions (Ress) Co-Precipitation, Beidi He

Dissertations

Nanoscale composites of hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX) and polymer binders were produced by co-precipitation using rapid expansion of supercritical solutions (RESS). The binders used in this study are poly (vinylidene fluoride-co-hexafluoropropylene) (VDF-HFP22), polystyrene (PS) and 7-amino-4-methyl coumarin (AMC). The RDX/VDF-HFP22 and RDX/PS co-precipitated nanoparticles were characterized by Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). The average size of produced nanoparticles is ca. 100 nm. TEM analysis of RDX/PS nano-composite shows a core-shell structure with RDX as the core material and the shell consisting of the polymeric binder. X-ray Powder Diffraction (XRPD) analysis …

Hydrodynamics, Dissolution, And Mass Transfer Effects In Different Dissolution Testing Apparatuses And Laboratory Systems, Bing Wang

Dissertations

Dissolution testing apparatuses and shaker flasks agitated by shaker tables are laboratory systems routinely found in many laboratories at most companies and agencies, and especially in pharmaceutical companies. These devices are commonly used in a number of applications, from drug development to quality control. Despite their common use, these systems have not been fully investigated from an engineering perspective in order to understand their operation characteristics. For example, the hydrodynamics of many of these systems have received little attention until relatively recently, and only over the last few years have some of these systems, such as the USP dissolution testing …

Modeling The Controlled Delivery Power Grid, Vinit Madhukar Sahasrabudhe

Theses

Competitive energy markets, stricter regulation, and the integration of distributed renewable energy sources are forcing companies to reengineer energy production and distribution. The Controlled Delivery Power Grid is proposed as a novel approach to transport energy from generators to consumers. In this approach, energy distribution is performed in an asynchronous and distributed fashion. Much like the Internet, energy is delivered as addressable packets, which allow a controlled delivery of energy.

As a proof-of-concept of the controllable delivery grid, two experimental test beds, one with integrated energy storage and another with no energy storage, were designed and built to evaluate the …

Effect Of Endplate On The Blast Wave Profile In A Compressed Gas Shock Tube, Sudeepto Kahali

Theses

Blast related brain injuries are commonly encountered in the recent wars of Iraq and Afghanistan increased use of improvised explosive devices (IEDs). An estimated 20% of veterans returning from these operations have suffered traumatic brain injuries (TBI). The mechanisms and long-term effects of the injury are not fully understood, and extensive research effort is being focused toward identifying the mechanisms of primary blast injury. When a pure shock-blast wave encounters a subject, in the absence of shrapnel, casing or gaseous products, the loading is termed as primary blast loading, and its effects can be studied using shock tubes.

The wave …

New Screening Methodology For Selection Of Polymeric Materials For Transdermal Drug Delivery Devices, Roberto P. Falcone

Dissertations

As medical advances extend the human lifespan, the level of chronic illnesses will increase and thus straining the needs of the health care system that, as a result, governments will need to balance expenses without upsetting national budgets.

Therefore, the selection of a precise and affordable drug delivery technology is seen as the most practical solution for governments, health care professionals, and consumers.

Transdermal drug delivery patches (TDDP) are one of the best economical technologies that are favored by pharmaceutical companies and physicians alike because it offers fewer complications when compared to other delivery technologies. TDDP provides increased efficiency, safety …

High Frequency Field Potentials Of The Cerebellar Cortex, Jonathan David Groth

Dissertations

The cerebellum plays a crucial role in motor coordination along with basal ganglia and the motor areas of the cerebral cortex. Both somatosensory and the cerebro-cerebral pathways bring in massive amounts of neural information to the cerebellum. The output of the cerebellar cortex projects to various motor cortices as well as down to the spinal cord to make its contributions to the motor function.

The origin and function of the field potential oscillations in the cerebellum, especially in the high frequencies, have not been explored sufficiently. The primary objective of this study was to investigate the spatio-temporal characteristics of high …

Accounting For Midblock Pedestrian Activity In The Hcm 2010 Urban Street Segment Analysis, Albert Forde

Dissertations

The Urban Street segment analysis Chapter of the 2010 Highway Capacity Manual (HCM 2010) provides a methodology for analyzing automobile performance on signalized roadway segments within an urban roadway network. The methodology involves applying a platoon dispersion model to: a) predict the vehicle arrival flow profiles at a downstream signalized intersection; b) use the predicted arrivals to compute the proportion of vehicle arrivals on green; and c) subsequently estimate the delay, travel speed and Level of Service (LOS) under which the segment operates. Vehicles arriving during the red interval at a signalized intersection generally accumulate and form a platoon. When …

Optimization Methods For Active And Passive Localization, Nil Garcia

Dissertations

Active and passive localization employing widely distributed sensors is a problem of interest in various fields. In active localization, such as in MIMO radar, transmitters emit signals that are reflected by the targets and collected by the receive sensors, whereas, in passive localization the sensors collect the signals emitted by the sources themselves. This dissertation studies optimization methods for high precision active and passive localization.

In the case of active localization, multiple transmit elements illuminate the targets from different directions. The signals emitted by the transmitters may differ in power and bandwidth. Such resources are often limited and distributed uniformly …

Collaborative Rescheduling Of Flights In A Single Mega-Hub Network, Sufian Ikhmeis

Dissertations

Traditionally, airlines have configured flight operations into a Hub and Spoke network design. Using connecting arrival departure waves at multiple hubs these networks achieve efficient passenger flows. Recently, there has been much growth in the development of global single mega-hub (SMH) flight networks that have a significantly different operating cost structure and schedule design. These are located primarily in the Middle East and are commonly referred to as the ME3. The traditionalist view is that SMH networks are money losers and subsidized by sovereign funds.

This research studies and analyzes SMH networks in an attempt to better understand their flight …

System Design And Performance Analysis Of Asymmetrically And Symmetrically Clipped Optical (Asco)-Ofdm For Im/Dd Optical Wireless Communications, Nan Wu

Dissertations

As the quantity of mobile communication devices, such as cellphones, tablets, and laptops, dramatically increase, the demand for high speed wireless service has been growing. Optical wireless communications (OWCs), which offer unlimited transmission bandwidth, have received a lot of attention and been studied in recent decades. They can be an effective alternative to radio frequency communications (RFCs) for indoor high speed data transmission. Intensity modulation direct detection (IM/DD) is a simple way to realize the transmission of optical wireless signals in an indoor environment. Information data streams are modulated into the intensity of optical carriers and transmitted by light emitting …

Piezoelectric Scaffolds For Osteochondral Defect Repair, Sita Mahalakshmi Damaraju

Dissertations

Osteoarthritis is one of the most prevalent causes of disability affecting nearly 27 million Americans. Osteoarthritis is caused when extensive damage occurs to the articular cartilage later spreading to the underlying subchondral bone, resulting in osteochondral defects. The current clinical therapies aim at regenerating the hyaline cartilage, but instead fibrocartilage forms at the osteochondral defect site, which is inferior in structure and function and fails to integrate with the surrounding tissue. A biomimetic scaffold, which can provide cues similar to the native extracellular matrix, may facilitate osteochondral defect repair. Articular cartilage and bone extracellular matrix have been shown to produce …

Processing And Characterization Of Graphene And Graphene On Silicon, Cheng Peng

Theses

Graphene has become a promising material for applications in many areas including electronic devices, batteries and space crafts. Although it has a bright future, the commercial production of graphene has not yet been realized. In this thesis, an overview of the properties and applications of graphene is presented. The early research of preparing graphene and its composites is summarized, which gives the basis to synthesize graphene and improve the process. In this study, graphene oxide (GO) and graphene have been successfully made using graphite; graphene layer has been coated on the surface of a silicon wafer. The resulting specimens are …

An Extended Duration Operation For Solid Hollow Fiber Cooling Crystallization Method, Chi Jin

Theses

As recently demonstrated by Chen et al. [1], the solid hollow fiber cooling crystallization method to achieve continuous polymer coating/encapsulation of submicrometer particles, has advantages of no problem with high pressure, easy scale-up and production of free-flowing coated particles. There is a concern whether this crystallization method can be applied for an extended duration coating process; it was not investigated in the previous study. Therefore, in order to examine this problem, in this work, the duration of the whole crystallization coating process has been greatly extended from 5 min to 60 min and 120 min. For the purpose of being …

Principles And Applications Of Mechanical Dry Coating - Review And State-Of-The-Art, Sayani Bhaumik

Theses

Dry Coating of powders to form composite particulates has been firmly established and has garnered interest both in academia and industry due to its myriad applications. This thesis work is an attempt to map the progress of the dry coating technology from its incipient years in the '80s to the thriving practice in the present day. Dry coating is a relatively simple approach to coat powders with specific guest particles via mechanical means to produce composites with desired tailor-made properties, without the constraints of harmful emissions or huge capital investment. Composite particulates with enhanced flowability, high-temperature resistant properties, and modified …

Computational Studies Of Electronic Structure Of Doped Graphene, Yan Chu

Theses

In the literature, extensive studies have been performed to study the electronic properties of doped graphene. This is due to the potentially large number of applications of graphene in p-n junctions, transistors, photodiodes and lasers. By utilizing single heteroatom chemical doping method or electric field-induced method, one can introduce a band gap, ranging from 0.1eV to 0.5eV, in graphene. A tunable bandgap is highly desirable because it would allow significant flexibility in the design and optimization of such devices, particularly if it could be tuned by adjusting the doping configurations. Here, we demonstrate the realization of a widely tunable electronic …

Modeling Of Electrical Behavior Of Graphene-Based Ultracapacitors, Patrick Dzisah

Theses

Graphene has been identified as a promising material for energy storage, especially for high performance ultracapacitors. Graphene-based ultracapacitors show high stability, significantly-improved capacitance and energy density with fast charging and discharging time at a high current density, due to enhanced ionic electrolyte accessibility in deeper regions. The surface area of a single graphene sheet is 2630 m2/g, substantially higher than values derived from Brunauer Emmett Teller (BET) surface area measurements of activated carbons used in the current electrochemical double layer capacitors.

In an ultracapacitor cell, chemically modified graphene (CMG) materials demonstrate high specific capacitances of 135 and 99 F/g in …

Structural Health Monitoring Of Bridges Using Wireless Sensor Networks, Seyed Behrad Ghazi Sharyatpanahi

Theses

Structural Health Monitoring, damage detection and localization of bridges using Wireless Sensor Networks (WSN) are studied in this thesis. The continuous monitoring of bridges to detect damage is a very useful tools for preventing unnecessary costly and emergent maintenance. The optimal design aims to maximize the lifetime of the system, the accuracy of the sensed data, and the system reliability, and to minimize the system cost and complexity

Finite Element Analysis (FEA) is carried out using LUSAS Bridge Plus software to determine sensor locations and measurement types and effectively minimize the number of sensors, data for transmission, and volume of …

Thermal Properties Of Graphene, Vishal Vijay Nakhate

Theses

The two-dimensional (2D) monolayer structure of carbon atoms were initially considered as unstable. The 2D materials have recently been discovered and many researchers have started analyzing these materials. Graphene, a two-dimensional allotrope of graphite with sp2 bonded carbon atoms, is arranged in honeycomb structure. Graphene has excellent thermal conductivity and can be considered as a potential material for applications in the electronics industry where heating of materials is a serious concern.

In this study, thermal properties of p and n doped graphene nanosheets and nanoribbons are studied as function of percentage composition of the dopants and the direction of dissipation …

Tendon Reflex Protocol For Exploring The Mechanisms Associated With Whole Body Vibration, Ikechukwu Okeke

Theses

Whole body vibration (WBV) machines have in recent years been widely used as rehabilitation equipment. Whole body vibration has been shown to have positive effects on muscle response. Cerebral palsy (CP) is a neurodevelopmental condition that includes a group of non-progressive, but often changing, motor impairment syndromes arising in the early stages of human development. The aim of this project was to design a protocol and related instruments to assess the tendon reflex in response to WBV. Both a press pedal used for measuring the force exerted by the foot and a hammer used for measuring the stimulating force were …

Behavior Of Deformed Dermal Fibroblasts Seeded On A Silicon Membrane Under High Levels Of Strain, Laura Osorno

Theses

The main objective of this thesis is to understand, from a molecular perspective, the morphological and functional abnormalities of human dermal fibroblasts as a response to deformation produced by a normal force that can lead to the potential formation of stretch marks in pregnant women, adolescents, and people with Cushing's syndrome. The main function of dermal fibroblasts is to produce the essential fibrous components of the extracellular matrix (ECM) of the skin.

In order to study the mechanism of stretch mark formation, neonatal human dermal fibroblasts were seeded on a silicon membrane for controlled deformation. Upon reaching a confluence of …

Experimental Determination Of The Agitation Requirements For Solids Suspension In Dissolution Systems Using A Mini Paddle Apparatus, Yang Song

Theses

Dissolution testing is a critical step in quality control of manufactured final products in the pharmaceutical industry. The United State Pharmacopeia (USP) Dissolution Testing Apparatus 2 (paddle) is the most widely used dissolution test devices in the pharmaceutical industry to formulate solid drug dosage forms and to develop quality control specifications for its manufacturing process.

Mini vessels and mini paddle dissolution testing systems are smaller versions of the USP 2 Apparatus. The concept of the mini paddle apparatus is similar to that of the USP 2 setup but it is scaled down about to 1/5 of the volume and 40% …

Effect Of Impeller Submergence On Power Dissipation And Solids Suspension In Mixing Systems Equipped With Pitch-Blade Turbines, Yufeng Song

Theses

Mixing and dispersion of solids in a liquid is a process frequently encountered in the pharmaceutical industry and often conducted in cylindrical baffled tanks stirred by mechanical impellers. In operations where the liquid level is decreased (as often which emptying the tank) the process must be stopped when the solids are no longer suspended. In this work, the minimum agitation to suspend solids (Njs) when the liquid level was lowered, and the impeller submergence S_b changed as a result were determined for the case of a six-blade, pitch-blade turbine (6-PBT) impeller. The power consumed by the impeller …

Ultracapacitors For Off Grid Wind Power Systems, Hans Tanis

Theses

The main reason for wind turbine to be not as prevalent as traditional power systems is because they do not have an effective storage capacity. However, researchers in material science and engineering have found ways to resolve this problem by developing “ultracapacitors” that store energy by assembling ions at the surface of a porous material. That is why ultracapacitors coupled with the energy storage battery could present a challenge to the electrical power grid. Such a design allows ultracapacitors to charge in matter of minutes and not hours. This innovation would create a significant impact on electronic items such as …

Design, Construction And Characterization Ofa Magnetic Augmented Rotation System (Mars) Based Wind Turbine, Da Li

Theses

Magnetic Augmented Rotation System (MARS) works by magnetic field coupling, to transfer torque from the driver to the rotor without contact. This characteristic has significant applications to the wind turbine but research in combination of MARS and wind turbine has not been done in the literature. In this thesis, a small-scale wind turbine is designed, built and characterized in a prototype wind tunnel. The test results are analyzed and computer-aided software simulation is used as an auxiliary method to understand the mechanism of MARS. The power coefficient of this new wind turbine is estimated to be about 40%. The “gear …

Bio-Medicinal Application For Plasma Electrolytic Oxidation Of Metals, Zunjian Yang

Theses

Plasma electrolytic oxidation (PEO), a novel method for forming ceramic coatings on metals, has been researched extensively in recent times. By applying high voltage between dielectric thin films, a plasma micro-arc is induced through penetration of breakdown in film boiling layer. Such a method takes advantage of high processing time, low equipment requirement and advanced coating performance.

Titanium alloys, Ti-6Al-4V and pure Titanium Grade 2, are two of most common Titanium alloys in daily use. Both of such Titanium alloys show great potential utilization in bio-medicinal application, especially in implants, for its excellent biocompatibility, high tensile strength, and high elastic …

Optical Properties Of Black Silicon - An Analysis, Suramya Sekhri

Theses

Silicon is the preeminent solar cell material of the day because it is the first semiconductor that was learned to commercialize and continues to be the principal semiconducting material used in photovoltaic technology for the manufacture of solar cells. Silicon, an indirect band gap semiconducting material, has a reflectance of about 30% in the visible range of wavelengths. Standard Silicon solar cells are not entirely useful in the infrared spectrum region. In order to enhance the performance of Silicon solar cells, reflectance losses must be minimized and absorption must be maximized. In the solar cell industry, anti-reflection (AR) coating is …

The Kinetics Of Drug Dissolution In Polymers During Hot-Melt Extrusion, Huayang Fang

Theses

Extrusion has been a most important and widely used continuous process in polymer processing for over one hundred and fifty years. However, it has only been recently applied and adopted by the pharmaceutical industry to prepare solid oral dosage formulations with increased bioavailability for the poorly-water soluble drugs and controlled release characteristics for the water-soluble drugs. In pharmaceutical Hot-melt extrusion poorly water soluble drug particulates are mixed with water soluble polymer excipient particulates and fed in the extruder, where the polymer is melted, after which the drug particulates begin to dissolve into the polymer melt. Extrusion-generated mixing accelerates dissolution process. …

Simulation Of Electronic And Optical Properties Of Graphene, Biao Leng

Theses

Graphene is a recently discovered two-dimensional crystal. Due to its excellent electronic properties, transport properties, optical properties, and many other features, it has tremendous potential for applications in many areas. This thesis discusses the structure and properties of graphene using several different models of graphene and carries out detailed theoretical studies and calculations of its electronic and optical properties. Using two modules of Materials Studio, CASTAP and Doml3, four graphene models have been constructed. Their electronic and optical properties have also been calculated via these two modules. By comparing the results of calculations with experimental results and the literature, the …

Differentiation Of Mouse Embryonic Stem Cells Into Insulin-Producing Cells: Optimization To Enhance The Overall Differentiation Efficiency, Xiaotang Ma

Theses

Embryonic stem cells have the potential to differentiate into multiple cell types including insulin-producing cells (IPCs), which is becoming one of the promising cell sources for treating type 1 diabetes mellitus. However, in order to achieve functional stem cell-derived cells, it is important to generate more mature IPCs and to keep long-term viability post differentiation process. In this study, we varied several factors including different embryonic body culture conditions, digested cells seeding density and various coatings required for differentiation to optimize a previously established protocol to enhance the overall differentiation efficiency. Moreover, a three-dimensional in vitro collagen tissue culture system …

Experimental Determination Of Solids Suspension With Angled Impeller In A Pharmaceutical Mixing Vessel, Yingxi Tang

Theses

Angled-mounted impellers are commonly used in a number of pharmaceutical industry applications, from laboratory reactors to full-scale tanks. In these systems, the impeller is not centrally and vertically mounted, as in most stirred vessels, but it enters the vessel, and is therefore immersed in the fluid, at an angle from the vertical. This arrangement provides some baffling effects that would not otherwise exist if the impeller was centrally mounted.

One common requirement for such systems is that they are capable of suspending small solids dispersed in the liquid. Therefore, it is critical to know the value of the minimum agitation …