Engineering Commons^™

Theoretical Prediction Of Drug Release In Gi Tract From Spherical Matrix Systems, Naga Lakshmi Ramana Susarla

Dissertations

The significance of controlled release drug delivery systems (CRDDS) lies in their ability to deliver the drug at a steady rate thus reducing the dosage interval and providing a prolonged pharmacodynamic effect. But despite the steadily increasing practical importance of these devices, little is known regarding their underlying drug release mechanisms. Mathematical modeling of these drug delivery systems could help us understand the underlying mass transport mechanisms involved in the control of drug release. Mathematical modeling also plays an important role in providing us with valuable information such as the amount of drug released during a certain period of time …

Dispersion Of Particles On Liquid Surfaces, Sathishkumar Gurupatham

Dissertations

When small particles (e.g., flour, pollen, etc.) come in contact with a liquid surface, they immediately disperse. The dispersion can occur so quickly that it appears explosive, especially for small particles on the surface of mobile liquids like water. This explosive dispersion is the consequence of capillary force pulling particles into the interface causing them to accelerate to a relatively large velocity. The maximum velocity increases with decreasing particle size; for nanometer-sized particles (e.g., viruses and proteins), the velocity on an air-water interface can be as large as 47 m/s. They also oscillate at a relatively high frequency about their …

The Impact Of Dynamic And Passive Standing On Bone Mineral Density And Appositional Growth In Immobilized Children, Megan Diane Damcott

Dissertations

The first discovery of the potential role that mechanical loading has on determining the strength of bone occurred in 1892. However, for almost a century after this discovery, the specific mechanisms influenced by mechanical loading remained locked in a mysterious 'black box'. Then in the 1960s, the 'black box' was opened and continued work has now unlocked the basic mechanisms involved in mechanical loading and whole-bone strength. This increased knowledge has spurred clinicians and researchers to investigate the impact of weight-bearing interventions on individuals with an increased risk of osteoporosis. The most common weight-bearing clinical intervention used in non-ambulant populations …

Effects Of Operating And Geometric Variables On Hydrodynamics And Tablet Dissolution In Standard And Modified Dissolution Testing Apparatuses 2, Yimin Wang

Dissertations

Dissolution testing is routinely conducted in the pharmaceutical industry to provide critical in vitro drug release information for quality control purposes, and especially to assess batch-to-batch consistency of solid oral dosage forms such as tablets. Among the different types of apparatuses listed in the United States Pharmacopoeia (USP), the most commonly used dissolution system for solid dosage forms is the USP Dissolution Testing Apparatus 2, consisting of an unbaffled, hemispherical-bottomed vessel equipped with a 2-blade radial impeller.

Despite its extensive use in industry and a large body of work, some key aspects of the hydrodynamics of Apparatus 2 have received …

Synthesis And Development Of Boron Nanotubes And Metal/Ceramic-Carbon Nanotube Composites, Jinwen Liu

Dissertations

The first part of this thesis will be focused on developing a facile and scalable solid — solid chemical vapor deposition (CVD) process using a solid boron precursor to synthesize crystalline boron nanotubes (BNTs) mixed with small amounts of boron nanofibers (BNFs). The synthesis involves the use of solid boron precursors - magnesium boride and magnesium borohydride, magnesium and nickel boride as co-catalysts, and porous MCM-41 zeolite as the growth template. Experimental parameters, such as temperature, grinding of constituents and starting precursor-catalyst-template compositions, were studied and optimized. Detailed characterization have been carried out using field-emission scanning electron microscopy (FE-SEM), transmission …

Multifunctional Reactive Nanocomposite Materials, Demitrios Stamatis

Dissertations

Many multifunctional nanocomposite materials have been developed for use in propellants, explosives, pyrotechnics, and reactive structures. These materials exhibit high reaction rates due to their developed reaction interfacial area. Two applications addressed in this work include nanocomposite powders prepared by arrested reactive milling (ARM) for burn rate modifiers and reactive structures. In burn rate modifiers, addition of reactive nanocomposite powders to aluminized propellants increases the burn rate of aluminum and thus the overall reaction rate of an energetic formulation. Replacing only a small fraction of aluminum by 8Al•MoO₃ and 2B•Ti nanocomposite powders enhances the reaction rate with little change …

Effect Of Dry Particle Coating On The Properties Of Cohesive Pharmaceutical Powders, Lauren Elizabeth Beach

Dissertations

Engineered particles, which have undergone surface modification via dry coating, have been previously shown to have improved flow and handling properties. The improvements in these properties can be applied and are very useful for a number of industrial applications, in this case the pharmaceutical industry. This work investigates the effect of dry particle coating to improve the flowability of cohesive active pharmaceutical ingredient (API) powders and their blends. Improving the flow properties of cohesive API powders can significantly improve their handling and subsequent use for pharmaceutical processes such as formulation and manufacturing processing operations. Although it has been shown that …

A 3-Dimensional Vascularized Cardiac Tri-Culture Model Using Chitosan Nanofiber Scaffolds, Ali Hussain

Dissertations

The development of an in vitro tissue model that can mimic the 3-dimenisonal (3-D) cellular architecture and mosaic of myocardial tissue holds great value for cardiac tissue engineering, modeling, and cardiovascular drug screening applications. The main objective of this project was to develop a 3-D vascularized cardiac tissue model in vitro for improved survival and function.

The cellular mosaic of the myocardial tissue demands the intricate integration of an extracellular matrix-like scaffold, cellular constituents, and biological factors. The first aim of the research was to fabricate and characterize a biodegradable chitosan nanofiber scaffold that would resemble the extracellular matrix (ECM) …

A Study Of Three Transition Metal Compounds And Their Applications, Zhen Qin

Dissertations

The La_5/8-yPr_yCa_3/8MnO₃ with colossal magnetoresistance (CMR) effect has a rich phase diagram and is well studied for its electronic phase separation phenomenon, where the ferromagnetic (FM) metal order co-exists and competes with the charge-ordered (CO) insulator phase. High Pr doping will favor the CO order, leading a sharp FM to CO dominated phase transition around Pr concentration of 0.3 and above. Hydrostatic pressure favors FM metallic order without damaging the sample and can be tuned continuously. In this study, pressurized-magnetic and resistivity measurements was done on a La_0.25Pr_0.375Ca_{0.375 …}

Electrodeless Electro Hydrodynamic Printing Of Personalized Drug Dosages, Ezinwa Okeoma Elele

Dissertations

There is compelling evidence that variability in drug efficacy in individuals depends on their genetic fingerprints. These observations have given rise to the concept of personalized therapy whose ultimate goal is to develop medicinal agents designed for each niche of the population and individual patients according to their genetic background. The drawback in current pharmaceutical technologies is that most processes are designed to target large population and are unable to meet the demand of small-scale manufacturing of tailored therapeutics with diverse range of physical properties. One of the major challenges lie in developing efficient and cost effective methods of manufacturing …

Magnetic Seeding Aggregation To Enhance The Removal Efficiency Of Tio2 Nanoparticles From Water, Ashish Dhananjay Borgaonkar

Dissertations

Engineered nanoparticles, such as titanium dioxide (TiO₂), are important building blocks for the evolution of nanotechnology in industries and commercial products. Ever so increasing use of the engineered nanoparticles is bound to result in a substantial fraction of these nanoparticles ending up in wastewater; or surface water and groundwater, which are sources of intake for drinking water treatment. Removal of these engineered nanoparticles in wastewater and drinking water treatment processes is a very important step towards the protection of environmental and public health as well as protecting water treatment units from fouling and other issues.

Experimental studies showed …

Deagglomeration And Mixing Via The Rapid Expansion Of High Pressure And Supercritical Suspensions, Daniel To

Dissertations

Nano-materials are the focus of many research activities due to the desirable properties imparted from their small grain size and high interfacial surface area. However, these materials are highly cohesive powders in the dry state and typically form large agglomerates, leading to a diminished surface area or even grain growth, which minimizes the effectiveness of these nanomaterials. This dissertation addresses the issue of mixing nanopowders constituents by deagglomerating them and achieving simultaneous mixing so that even after inevitable reagglomeration, the effectiveness of large interfacial surface area may be preserved.

Nano-particle mixtures were prepared using the environmentally benign dry mixing methods …

Study Of The Heating And Ignition Of Metal Powder By Electrostatic Discharge, Ervin Beloni

Dissertations

The objective of this work was to understand the processes that lead to ESD stimulated ignition events in metal powders. Several metals were studied: Mg, Al, and Ti. A commercially available ESD test device was adapted for the present experiments. The ESD current and voltage were measured using inductance coils; the data were used to determine the electric circuit impedance, and energy transferred to the powder. A mode of the powder ignition (individual particles vs. dust cloud), ignition delays, burn times, and velocities of ignited and ejected particles were determined from optical measurements.

It was determined that the ESD energy …

A Study Of The New York / New Jersey Coastal Water : Bio-Optical Characteristics Of The Harbor Estuary And The Effects Of Heavy Metals On Brown Tide Alga Of The Bight, Bin Wang

Dissertations

The New York / New Jersey (NY/NJ) coastal area is one of the most productive regions around the world and a major natural and scenic resource for New York and New Jersey. As a result of excessive nutrient loading in the water, algal blooms have been observed since 1950’s. The NY/NJ coastal area includes the NY/NJ Bight and the NY/NJ Harbor Estuary, and in the former, brown tides (Aureococcus anophagefferens) were first observed in 1985 becoming a more serious water quality problem over the last 25 years. The influence of micronutrients, namely trace metals, on A. anophagefferens that are widespread …

Efficient Packet Delivery In Modern Communication Networks, Nan Wang

Dissertations

Modern communication networks are often designed for diverse applications, such as voice, data and video. Packet-switching is often adapted in today’s networks to transmit multiple types of traffic. In packet-switching networks, network performance is directly affected by how the networks handle their packets. This work addresses the packet-handling issues from the following two aspects: Quality of Service (QoS) and network coding.

QoS has been a well-addressed issue in the study of IP-based networks. Generally, nodes in a network need to be informed of the state of each communication link in order to make intelligent decisions to route packets according to …

Optimizing Resource Allocation In Next-Generation Optical Access Networks, Jingjing Zhang

Dissertations

To meet rapidly increasing traffic demands caused by the popularization of Internet and the spouting of bandwidth-demanding applications, Passive Optical Networks (PONs) exploit the potential capacities of optical fibers, and are becoming promising future-proof access network technologies. On the other hand, for a broader coverage area and higher data rate, integrated optical and wireless access is becoming a future trend for wireless access. This thesis investigates three next-generation access networks: Time Division Multiplexing (TDM) PONs, Wavelength Division Multiplexing (WDM) PONs, and WDM Radio-Over-Fiber (RoF) Picocellular networks.

To address resource allocation problems in these three networks, this thesis first investigates respective …

Modeling Of Non-Uniform Hydrodynamics And Catalytic Reaction In A Solids-Laden Riser, Rajeshkumar Patel

Dissertations

The riser reactors are widely used in a variety of industrial applications such as polymerization, coal combustion and petroleum refinery because of the strong mixing of gas and solids that yields high heat and mass transfer rates, and reaction rates. In a Fluid Catalytic Cracking (FCC) process, the performance of riser reactor is strongly dependent on the interaction between the fluid and catalysts, since the reaction takes place on the active surface of the catalysts. This is why, the local coupling between hydrodynamics and reaction kinetics is critical to the development of riser reaction models. The local gas-solids flow structure …

Design Of Single-Carrier Frequency Domain Equalization (Sc-Fde) With Transmit Diversity For Wireless And Optical Communications, Kodzovi Acolatse

Dissertations

As the demand of wireless service is rising, there is a need to transmit high-speed packets over the wireless communication channel. Broadband data transmission over wireless channels commonly faces the challenges of multipath fading channels, which are both time and frequency selective. There is then a need to design transmission techniques that can combat the adverse effects of the channel, and enable reliable high data rate wireless services. Orthogonal frequency division multiplexing (OFDM) has become widely accepted primarily because of its robustness against frequency selective fading channels, but it suffers a number of drawbacks such as high peak-to-average power ratio …

Risk Based Models For The Optimization Of Oil And Gas Supply Chain Critical Infrastructure, Kingsley Oseloka Achebe

Dissertations

The oil and gas sector faces a broad array of risks and uncertainties, affecting short- and long-term planning, and causing adverse effects in the energy sector. To predict and minimize them, risk based supply chain models were developed for the oil and gas supply chain critical infrastructure.

First, the events and activities were categorized as short term and long term, and their risk ratings derived, by analyzing data from past events and site visits. The result showed that events like the Israel – Arab war, successful hurricane, and production increase or decrease, had a risk rating of approximately 7.

Second, …

Modeling Of Equilibrium Point Trajectory Control In Human Arm Movements, Kai Chen

Dissertations

The underlying concept of the Equilibrium Point Hypothesis (EPH) is that the CNS provides a virtual trajectory of joint motion, representing spacing and timing, with actual movement dynamics being produced by interactions of limb inertia, muscle viscosity and speed/position feedback from muscle spindles. To counter criticisms of the EPH, investigators have proposed the use of complex virtual trajectories, non-linear damping, stiffness and time varying stiffness to the EPH model. While these features allow the EPH to adequately produce human joint velocities, they conflict with the EPH’s premise of simple pre-planned monotonic control of movement trajectory. As a result, this study …

Factors That Impact Seat Belt Usage And Injury Severity Of Belted Front Seat Occupants, Siri Konje Lawrencia Nukenine

Dissertations

Factors influencing seat belt usage have been extensively researched in the safety analysis literature. Most of this research has focused on factors that influence seat belt usage for a driver and front seat passenger in a vehicle. Few research studies have investigated factors that impact seat belt usage for back seat occupants. This research investigates the factors associated with seat belt usage for front-seat as well as backseat occupants of vehicles in the state of New Jersey. Using logistic regression, seat belt usage models were developed to examine the contribution of several variables on seat belt usage for five vehicle …

Application Of Mass/Stiffness Eccentricity To Control Response Of Structures Subjected To Earthquake Ground Motion, Bakhtiar Feizi

Dissertations

This dissertation is driven by the concept that engaging more modes in the response of structures can be used to mitigate its translational dynamic response. One such an approach is to engage torsional modes through engineered eccentricity (mass/stiffness eccentricity), thus, introducing coupled translation-rotation response. This idea was first introduced in a paper published by MacBain and Spillers in 2004. As a follow up to the same idea this dissertation was an attempt to investigate and develop the theory concerning the application of mass/stiffness eccentricity to control the translational motion of structures subjected to earthquake ground motion.

Different discrete and continuous …

Study Of Mechanisms Of Phytotoxicity Of Alumina Nanoparticles, Anthony Elijius

Dissertations

Plant growth inhibitory effect of alumina nanoparticles has recently been reported (Ling Y, Watts D, 2004) but the mechanisms of such an effect are yet to be established. The phytotoxicity of aluminum and some of its compounds is well known, but the rapid expansion of nanotechnology resulting in the introduction of new sets of materials in the nanometer range has led to the development of new approaches, experimental methods and modes of investigation.

In this study, the observed phytotoxic effects of alumina nanoparticles suspension on five plant species (Zea mays, Cucumis sativus, Daucus carota, Brassica oleracea, Lactuca sativa) …

Mixing Of Nanosize Particles By Magnetically Assisted Impaction Techniques, James V. Scicolone

Dissertations

Nanoparticles and nanocomposites offer unique properties that arise from their small size, large surface area, and the interactions of phases at their interfaces, and are attractive for their potential to improve performance of drugs, biomaterials, catalysts and other highvalue- added materials. However, a major problem in utilizing nanoparticles is that they often lose their high surface area due to grain growth. Creating nanostructured composites where two or more nanosized constituents are intimately mixed can prevent this loss in surface area, but in order to obtain homogeneous mixing, de-agglomeration of the individual nanoparticle constituents is necessary.

Due to high surface area, …

Tin/Hfo2/Sio2/Si Gate Stacks Reliability : Contribution Of Hfo2 And Interfacial Sio2 Layer, Nilufa Rahim

Dissertations

Hafnium Oxide based gate stacks are considered to be the potential candidates to replace SiO₂ in complementary metal-oxide-semiconductor (CMOS), as they reduce the gate leakage by over 100 times while keeping the device performance intact. Even though considerable performance improvement has been achieved, reliability of high-κ devices for the next generation of transistors (45nm and beyond) which has an interfacial layer (IL: typically SiO₂) between high-κ and the substrate, needs to be investigated. To understand the breakdown mechanism of high-κ/SiO₂ gate stack completely, it is important to study this multi-layer structure extensively. For example, (i) the …

Distributed Synchronization Algorithms For Wireless Sensor Networks, Nicola Varanese

Dissertations

The ability to distribute time and frequency among a large population of interacting agents is of interest for diverse disciplines, inasmuch as it enables to carry out complex cooperative tasks. In a wireless sensor network (WSN), time/frequency synchronization allows the implementation of distributed signal processing and coding techniques, and the realization of coordinated access to the shared wireless medium. Large multi-hop WSN's constitute a new regime for network synchronization, as they call for the development of scalable, fully distributed synchronization algorithms. While most of previous research focused on synchronization at the application layer, this thesis considers synchronization at the lowest …

Model Reference Control For Ultra-High Precision Positioning Systems, Lan Yu

Dissertations

Due to the increasing demands of high-density semiconductors, molecular biology, optoelectronics, and MEMS/NEMS in the past decades, control of ultra-high precision positioning using piezoelectricity has become an important area because of its high displacement resolution, wide bandwidth, low power consumption, and potential low cost. However, the relatively small displacement range limits its application. This work proposed a practical ultra-high precision piezoelectric positioning system with a complementary high displacement range actuation technology. Solenoids are low cost, high speed electromagnetic actuators which are commonly used in on-off mode only because of the inherent high nonlinear force-stroke characteristics and unipolar forces (push/pull) generated …

Study Of Controlled Release Of Active Pharmaceutical Ingredients From Functionalized Nanoclays And Polymer Matrices, Jin Uk Ha

Dissertations

This dissertation contains the results of three related novel investigations in the field of structure-property-processing relationships of pharmaceutical polymer-based products. They are: a) modification of a pharmaceutical anionic nanoclay with two different Active Pharmaceutical Ingredients (APIs) to produce nanohybrid API carriers intended to be used alone or in acrylic polymer matrices, b) comparison of binary systems containing the above APIs in the selected acrylic polymers in terms of their miscibilities with the polymer, but in the absence of nanoclay, and c) comparison of the polymer/API binary systems with ternary polymer/API/Clay systems.

For the first study, the calcination method which can …

Underwater Communication Via Particle Velocity Channels : Principles, Channel Models, And System Design, Huaihai Guo

Dissertations

A vector sensor is capable of measuring important non-scalar components of the acoustic field such as the particle velocity, which cannot be obtained by a single scalar pressure sensor. In the past few decades, extensive research has been conducted on the theory and design of vector sensors. On the other hand, underwater acoustic communication systems have been relying on scalar sensors only, which measure the pressure of the acoustic field. By taking advantage of the vector components of the acoustic field, such as the particle velocity, the vector sensor can be used for detecting the transmitted data. In this dissertation, …

Seismic Characterization Of Recycled Aggregate Concrete, Amin Jamali

Dissertations

There are significant environmental benefits of recycling waste concrete and reusing it as aggregate for structural concrete, but the use of Recycled Aggregate Concrete (RAC) is yet limited to non-structural applications such as road sub-base. Widespread application of RAC in areas such as seismic design requires an improved knowledge of RAC behavior under multiaxial state of stresses.

The main objective of this research is the characterization of seismic properties of RAC by developing a stress-strain model which can reasonably describe the behavior under both unconfined and confined conditions. An extensive experimental program, including testing of several plain RAC cylinders as …