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2008

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Articles 1 - 30 of 4970

Full-Text Articles in Engineering

Effect Of Microreactor Geometry In Performance Of Catalytic Microreactor Of Hydrogen Production By Cfd Modeling, Mohsen Behnam, Ali Fazeli, Shohreh Fatemi, Yadolah Mortazavi, A. Khodadai Feb 2010

Effect Of Microreactor Geometry In Performance Of Catalytic Microreactor Of Hydrogen Production By Cfd Modeling, Mohsen Behnam, Ali Fazeli, Shohreh Fatemi, Yadolah Mortazavi, A. Khodadai

Ali Fazeli

Hydrogen production from steam reforming of methanol for fuel cell application was modeled in a wall coated micro channel reactor by CFD approach. Heat of steam reforming was supplied from catalytic total oxidation (TOX) of methanol in neighboring channel of steamreforming (SR) channel and conduct from TOX to SR channel through metal divider wall of the channels. Heat integration was compared in zigzag and straight geometry of microreactor by CFD modeling. The model is 2 dimensional, steady state and containing five zones: TOX fluid, TOX catalyst layer, steel wall of the channel, SR catalyst layer, SR fluid. Set of partial ...


Surface And Bulk Passivation Of Multicrystalline Silicon Solar Cells By Silicon Nitride (H) Layer : Modeling And Experiments, Chuan Li Dec 2008

Surface And Bulk Passivation Of Multicrystalline Silicon Solar Cells By Silicon Nitride (H) Layer : Modeling And Experiments, Chuan Li

Dissertations

The objective of this dissertation is to study passivation effects and mechanisms in Si solar cells, specifically, the surface and bulk passivation by hydrogen-rich PECVD silicon nitride (SiN :H) antireflection layer on multicrystalline silicon (me-Si) solar cells.

The passivation of silicon surface can be achieved in two ways: by field-effect passivation and/or by neutralization of interface states. In other words, the deposition should result in a high value of fixed charge, Qf and /or a low value of interface state density, D1. The surface recombination velocity can be described by Shockley-Read-Hall (SRH) statistics.

Current SRH formalisms have failed to ...


Experiment And Modeling : Ignition Of Aluminum Particles With A Co2 Laser, Salil Mohan Dec 2008

Experiment And Modeling : Ignition Of Aluminum Particles With A Co2 Laser, Salil Mohan

Dissertations

Aluminum is a promising ingredient for high energy density compositions used in propulsion systems, explosives, and pyrotechnics. Aluminum powder fuel additives enable one to achieve higher combustion enthalpies and reaction temperatures. Therefore, to develop aluminum based novel and customized high density energetic materials, understanding of ignition and combustion kinetics of aluminum powders is required. In most practical systems, metal ignition and combustion occur in environments with rapidly changing temperatures and gas compositions. The kinetics of exothermic reactions in related energetic materials is commonly characterized by thermal analysis, where the heating rates are very low, on the order of 1 -50 ...


Optimizing Container Retrieval Operation At A Port Container Terminal, Dejan Besenski Dec 2008

Optimizing Container Retrieval Operation At A Port Container Terminal, Dejan Besenski

Dissertations

In the presence of major challenges, where ports are striving to improve their operation and stay competitive in the global market, the issue of port efficiency, particularly the intelligent management of straddle carriers is investigated in this study. A new approach is presented that optimizes container handling equipment operation and is beneficial for the terminal operator in terms of improving productivity, providing faster service and reducing operating cost, Also, the solution provides acceptable service for truckers, The operational strategies presented are able to assess the operation from the truckers' and terminal operators' perspective.

The research is structured into four different ...


Phosphate And Thermal Stabilization Of Heavy Metals In Dredged Sediments, Peter Kuria Ndiba Dec 2008

Phosphate And Thermal Stabilization Of Heavy Metals In Dredged Sediments, Peter Kuria Ndiba

Dissertations

Treatment and reuse of dredged harbor sediments in construction as an alternative to disposal reduces costs and conserves resources. This research focused on leachability of metal contaminants subsequent to phosphate addition and thermal treatment at 700 °C. X- ray absorption spectroscopy (XAS) in combination with principal component analysis, target transformation, and linear combination revealed that in the untreated sediments Zn precipitated as the relatively soluble smithsonite (ZnCO3) (67%) and adsorbed to hydrous iron oxides (15%) and hydrous manganese oxides (18%). Phosphate addition and calcination resulted in sparingly soluble phases, hopeite (Zn3(PO4)2.4H2O) (22 ...


Characterization Of Natural Organic Matter And Precursors To Trihalomethanes Using Spectral Flourescence Signatures, Krit Punburananon Dec 2008

Characterization Of Natural Organic Matter And Precursors To Trihalomethanes Using Spectral Flourescence Signatures, Krit Punburananon

Dissertations

Disinfection is an essential process to kill pathogens (i.e., disease causing organisms) in source water during the production of drinking water. Chlorine is most widely used disinfectant because it is effective, affordable, and also provides chlorine residual to ensure that the water is safe through the distribution system. Nonetheless, chlorine reacts with Natural Organic Matter (NOM) and forms potentially carcinogenic Disinfection By-products (DBPs). The major chlorination DBPs are dominantly Trihalomethanes (THMs). However, not all organic compounds are equally reactive to THMs formation.

NOM in water samples collected from the Delaware & Raritan Canal and its tributaries (Central New Jersey) was ...


Optimizing Fare Structure And Service Frequency For An Intercity Transit System, Feng-Ming Tsai Dec 2008

Optimizing Fare Structure And Service Frequency For An Intercity Transit System, Feng-Ming Tsai

Dissertations

This study presents an approach to jointly optimize service headway and differentiated fare for an intercity transit system with an objective of total profit maximization and with consideration given to the economic and social sustainability of the system. Service capacity and fleet size constraints are considered. The optimization problem is structured into four scenarios which are comprised of the combinations of whether the Ranges of Travel Distance (RTD) is fixed or variable and if the time period is for a single period or for multiple periods. A successive substitution method (specifically, a modified Gauss Southwell method) is applied to solve ...


Precipitation Of Micro/Nanoparticles In Enhanced High Energy Dissipation Mixing Systems, Giuseppe Di Benedetto Dec 2008

Precipitation Of Micro/Nanoparticles In Enhanced High Energy Dissipation Mixing Systems, Giuseppe Di Benedetto

Dissertations

Crystallization is the most common unit operation used in the pharmaceutical industry to synthesize active ingredients. Rapid development of a drug candidate is dependent on the ability to produce a desired drug substance with consistent properties, These properties include stability and purity, which are directly affected by the crystallization process and which affect, in turn, bioavailability, drug dissolution rate, drug stability, and shelf life.

The objective of this work is to produce micro/nanoparticle crystals within existent glass-lined pharmaceutical stirred-tank reactors by modifying the current reactor configuration to include features that can increase the local rate of energy dissipation in ...


Assessing Trainer Hand Forces For Manual Body Weight Supported Walking, Manish Raval Dec 2008

Assessing Trainer Hand Forces For Manual Body Weight Supported Walking, Manish Raval

Theses

Spinal cord injuries occur in approximately 12,000 to 15,000 people per year in the U.S. About 10,000 of these people are permanently paralyzed. Most spinal cord traumas occur in young, healthy individuals. Males between 15 and 35 years old are most commonly affected.

Recently new approaches to facilitate walking recovery for individuals after a spinal cord injury, have been directed towards a therapy known as Locomotor Training (LT) that implements repetitive stepping on a treadmill using body weight support. A major intent of LT research is to investigate the effect of an extended period of LT ...


Dual Parametric Sensors For Highly Sensitive Nucleic Acid Detection, Manu Sebastian Mannoor Dec 2008

Dual Parametric Sensors For Highly Sensitive Nucleic Acid Detection, Manu Sebastian Mannoor

Theses

The primary focus of this research work was on the design and development of a molecular scale (nano-scale) capacitive sensing mechanism for the highly sensitive and label-free detection of Nucleic Acid hybridization. These novel capacitive sensors with nano-scale electrode spacing offer solutions to many problems suffered by the conventional signal transduction mechanisms, thereby immensely improving the sensitivity of the biomolecular detection processes. Reducing the separation between the capacitive electrodes to the same scale as the Debye length of the sample solution, results in the overlapping of the electrical double layers of the two electrodes, thereby confining them to occupy a ...


Kinematic Synthesis Of Planar Four Bar And Geared Five Bar Mechanisms With Structural Constraints, Yahia Mohammad Al-Smadi Dec 2008

Kinematic Synthesis Of Planar Four Bar And Geared Five Bar Mechanisms With Structural Constraints, Yahia Mohammad Al-Smadi

Dissertations

In motion generation, the objective is to calculate the mechanism parameters required to achieve or approximate a set of prescribed rigid-body positions. This doctoral dissertation study is aimed to integrate the classical kinematic analysis of a planar four-bar and geared five-bar motion generation with three structural design constraints. These constraints consider driving link static torque, deflection of the crank and buckling of the follower for a given rigid-body load or constant external load.

This kineto-elastostatic analysis is based on the following assumptions to be considered during the analysis; the crank and the follower are elastic members and the coupler is ...


Electro Hydrodynamic Manipulation Of The Process Of Self-Assembly Of Particles At Fluid-Fluid Interfaces, Muhammad Mansoor Janjua Dec 2008

Electro Hydrodynamic Manipulation Of The Process Of Self-Assembly Of Particles At Fluid-Fluid Interfaces, Muhammad Mansoor Janjua

Dissertations

This dissertation is divided into two parts, first deals with the numerical study of motion of dielectric particles subjected to nonuniform electric fields and second deals with the process of self-assembly of particles at fluid-fluid interfaces and subjected to uniform electric field normal to the interface. In the numerical study, the particles are moved using a direct simulation scheme (DNS) in which the fundamental equations of motion of fluid and solid particles are solved without the use of models. The motion of particles is tracked using a distributed Lagrange multiplier method (DLM) and the electric force acting on the particles ...


Enhanced Fluidization Of Nanoparticle Agglomerates, Daniel Lepek Dec 2008

Enhanced Fluidization Of Nanoparticle Agglomerates, Daniel Lepek

Dissertations

Gas fluidization of nanoparticle agglomerates has recently received much attention due to the excellent way in which these novel nanornaterials can be dispersed in a gaseous medium. Nanopowders have a very high surface area to volume ratio which allows them have unique chemical and physical properties especially at the surface. Fluidization is a popular technique for the continuous dispersal of solid materials in the fluidlike state.

Recently it has been found that nanoparticles exist in a highly agglomerate state which allow them to become fluidizable. The fluidization behavior of the nanopowders is dependent on the bulk and material properties of ...


A Novel Storage Area Network (San) Extension Solution Over Passive Optical Networks (Pons), Si Yin Dec 2008

A Novel Storage Area Network (San) Extension Solution Over Passive Optical Networks (Pons), Si Yin

Dissertations

After 9/11 and the 2003 power grid failure in North America, storage area network (SAN) extension has emerged as a critical option to ensure business continuity. However, SAN extension encounters challenges in the access network including the scalability, cost, bandwidth bottleneck, and throughput. In this dissertation, a new solution, SAN extension over passive optical networks (S-PONs), has been proposed to address the above problems. PONs are the mainstream wireline technology for upgrading the megabit-level access solutions (such as xDSL and Cable Modem) into gigabit-level broadband access. To tackle the scalability problem and cost challenge, the S-PON architecture has been ...


Finger Walking Control Of A Two-Dimensional Walking Model Through Inverse Kinematics, Jordan Ratcliff Dec 2008

Finger Walking Control Of A Two-Dimensional Walking Model Through Inverse Kinematics, Jordan Ratcliff

Theses

Those people who have spinal cord injuries (SCI) must remain in wheelchairs due to disruption of the neural signaling to their muscles. Functional electrical stimulation (FES) has proved itself to be an option for restoring some motion and some walking for the patient. Electrodes can either be placed on the skin or muscle to provide an electrical impulse that stimulates the muscles into contraction. Current systems provide buttons that use set functions for left and right steps with constant direction and size. It is desired however that the user be allowed a more natural and variable control method of controlling ...


Evaluation Of Medical Alarm Sounds, Elizbha Philip Dec 2008

Evaluation Of Medical Alarm Sounds, Elizbha Philip

Theses

Auditory alarms in medical equipments perform considerably below their optimal level. Concern has been expressed about the quality of medical alarms by a large number of researchers in recent years. A detailed literature survey on the medical alarm related problems has been carried out. Hospital visits were made to obtain real life information and data of alarm sounds in various type of monitors used in OR and ICU. A laboratory experiment has been conducted on selected melodic alarm sounds. These melodic alarm sounds are being implemented in medical equipments and the idea of design is proposed in ISO / IEC 60601-1-8 ...


Aptamer-Based Nano-Scale Dielectric Sensor For Protein Detection, Teena James Dec 2008

Aptamer-Based Nano-Scale Dielectric Sensor For Protein Detection, Teena James

Theses

The specific detection and precise quantification of protein molecules play an essential role in basic discovery research as well as in clinical practice. In this research work, a novel protein detection mechanism based on nanoscale dielectric sensor functionalized with aptamer probes is developed. This work has been done in collaboration with Rational Affinity Devices LLC. The use of aptamer based detection offers several advantages over the traditional labor intensive antibody based immunosensing. In the initial phase of the work, the binding affinities of rationally designed oligomers towards a specific protein molecule (IgG) was studied and optimized under varying conditions of ...


Study And Development Of Ultrasound Monitoring Of Skeletal Defects, Kavil Patel Dec 2008

Study And Development Of Ultrasound Monitoring Of Skeletal Defects, Kavil Patel

Theses

Fatigue fractures are fine disruptions of normal bone architecture whose identification is often unreliable or difficult using x-rays (Robinson, Wilson et al.; Kundel 2004; Swischuk and Hernandez 2004). A fatigue fracture results from the application of abnormal loads to a bone with normal elastic resistance and is associated with new or different activity, and strenuous or repeated activity. The feasibility of using ultrasound to detect and monitor fatigue fractures and other structural damage in bone was established in this study.

The use of Low Transient Pulse (LTP) technology to drive the ultrasound transducers proved to enhance detection resolution and quality ...


Use Of Linear Predictive Features And Pattern Recognition Techniques To Develop A Vector Quantization Based Blind Snr Estimation System, Russell Paul Ondusko Iii Dec 2008

Use Of Linear Predictive Features And Pattern Recognition Techniques To Develop A Vector Quantization Based Blind Snr Estimation System, Russell Paul Ondusko Iii

Theses and Dissertations

Signal-to-noise ratio is defined as the ratio of a given transmitted signal to the background noise of the transmission medium. Signal-to-noise ratio (SNR) is a common concept found in all forms of electrical communications. The easiest way to measure the signal-to-noise ratio is through intrusive means in which a corrupt signal is compared to its original signal. This technique is inefficient and impractical because it requires the original signal and can only be used to theoretically test the noise properties of a channel rather than estimate the SNR of a communicated signal. Characteristics of speech signals can be used to ...


Investigation Of The Performance Of Flexible Pavement Systems Under Moving Loads Using Finite Element Analyses, Dona Jacqueline Johnson Dec 2008

Investigation Of The Performance Of Flexible Pavement Systems Under Moving Loads Using Finite Element Analyses, Dona Jacqueline Johnson

Theses and Dissertations

The introduction of larger and heavier aircraft with more complex wheel configurations is making the current design methods inadequate for airfield pavements. In addition, airport pavements experience significant wander. However, the effect of wander on airport pavement performance has not been evaluated. In previous studies, the stress interactions between each tire of a triple-dual-tandem (TDT) axle used on B-777 and A380 aircraft cannot be captured using a two-dimensional model. In addition, many of these studies have assumed a linear-elastic material behavior of the pavement layers.

The purpose of this study is to conduct a three-dimensional finite element analysis to quantify ...


Preparation Of Nanovehicles For Targeted Drug Delivery, Anagha Avinash Bhakay Dec 2008

Preparation Of Nanovehicles For Targeted Drug Delivery, Anagha Avinash Bhakay

Theses

Application of nanotechnology in pharmaceutical research has opened new frontiers for drug development and its efficient delivery. In recent years, the focus of the research has been on the engineering of nano/micro-particulate structures for efficient and targeted delivery of drugs for selective and enhanced absorption. This work throws light on the preparation of biodegradable and non-toxic nanoparticulate systems for targeted drug delivery. The drug vehicles were made by two different processes namely electrostatic interactions and desolvation process. The drug carriers made by these processes were found to be in the size range of 150-200nm which is necessary for cellular ...


Deciphering The Biology Of Axon Stretch-Growth, Joseph R. Loverde Dec 2008

Deciphering The Biology Of Axon Stretch-Growth, Joseph R. Loverde

Theses

Traditional nerve regeneration strategies focus on growth cone-mediated growth, a form of nerve growth that occurs primarily during embryogenesis. Early axons continue to grow from the end distal to the soma, seeking targets on which to synapse. It is believed that once the axons synapse, stretch-growth takes over and is responsible for the great lengths achieved by nerves of the central and peripheral nervous systems. Recent work has demonstrated stretch-growth in vitro resulting in dramatically increased growth rates compared to the growth cone. Here, the aim was to decipher the underlying biology associated with axon stretch-growth using two approaches. First ...


Nano-Structured Platforms As A Spectroscopic Tool, Ruiqiong Li Dec 2008

Nano-Structured Platforms As A Spectroscopic Tool, Ruiqiong Li

Theses

Nano-structured platforms have been studied for the purpose of enhancing weak fluorescence signals. Each platform was constructed as a thin oxide layer on top of a metal (aluminum) The oxide was perforated with hexagonal array of nano-holes. The pitch of the array was much smaller than the optical wavelengths used. Surface charge waves (Surface Plasmons) could be excited when the platform was oriented at specific direction with respect to the incident optical beam. At this point one can demonstrate that fluorescence signals could be amplified. Since the oxide (alumina) is bio-compatible, one can envision using such platforms in the study ...


Data Fusion Based Optimal Eeg Electrode Selection For Early Diagnosis Of Alzheimer's Disease, Brian Balut Dec 2008

Data Fusion Based Optimal Eeg Electrode Selection For Early Diagnosis Of Alzheimer's Disease, Brian Balut

Theses and Dissertations

As medicinal and technological advances lengthen the average human life span, diseases affecting the elderly such as Alzheimer's disease and Parkinson's disease are seeing increasingly growing numbers, especially in developed countries. As a result, the necessity for an accurate, inexpensive, noninvasive means of diagnosis becomes particularly important, since such a method is not readily available to the general population. One biomarker that has recently showed promise is the analysis of the electroencephalogram (EEG).

Over the course of two studies, more than 130 subjects have been recruited providing information from 16-19 EEG electrodes for each subject. These signals have ...


Ensemble Of Classifiers Based Data Fusion Of Eeg And Mri For Diagnosis Of Neurodegenerative Disorders, Tejash Patel Dec 2008

Ensemble Of Classifiers Based Data Fusion Of Eeg And Mri For Diagnosis Of Neurodegenerative Disorders, Tejash Patel

Theses and Dissertations

The prevalence of Alzheimer's disease (AD), Parkinson's disease (PD), and mild cognitive impairment (MCI) are rising at an alarming rate as the average age of the population increases, especially in developing nations. The efficacy of the new medical treatments critically depends on the ability to diagnose these diseases at the earliest stages. To facilitate the availability of early diagnosis in community hospitals, an accurate, inexpensive, and noninvasive diagnostic tool must be made available. As biomarkers, the event related potentials (ERP) of the electroencephalogram (EEG) - which has previously shown promise in automated diagnosis - in addition to volumetric magnetic resonance ...


Exploration Of Multiple Pathways For The Development Of Immersive Virtual Reality Environments, Kevin Laurence Garrison Dec 2008

Exploration Of Multiple Pathways For The Development Of Immersive Virtual Reality Environments, Kevin Laurence Garrison

Theses and Dissertations

The focus of this thesis is the study and recommendation of optimal techniques for developing immersive virtual environments for generic applications. The overarching objective is to ensure that virtual environments can be created and deployed, rapidly and accurately, using commercial off-the-shelf software. Specific subjective and objective criteria have been employed to determine trade-offs between multiple pathways for designing such environments and specific recommendations are made for the applicability of each. The efficacy of the techniques developed as part of this research work has been demonstrated by applying them to three widely differing areas - visualizing arbitrary 2D surface data, synthesis of ...


Quad General Tree Drawing Algorithm And General Trees Characterization: Towards An Environment For The Experimental Study On General Tree Drawing Algorithms, Chu Yao Dec 2008

Quad General Tree Drawing Algorithm And General Trees Characterization: Towards An Environment For The Experimental Study On General Tree Drawing Algorithms, Chu Yao

Theses and Dissertations

Information visualization produces (interactive) visual representations of abstract data to reinforce human cognition and perception; thus enabling the viewer to gain knowledge about the internal structure of the data and causal relationships in it. The visualization of information hierarchies is concerned with the presentation of abstract hierarchical information about relationships between various entities. It has many applications in diverse domains such as software engineering, information systems, biology, and chemistry. Information hierarchies are typically modeled by an abstract tree, where vertices are entities and edges represent relationships between entities. The aim of visualizing tree drawings is to automatically produce drawings of ...


Methods And Apparatus For Preventing A Third Party From Overhearing A Telephone Conversation, Thaddeus Gabara, Vladimir I. Prodanov Dec 2008

Methods And Apparatus For Preventing A Third Party From Overhearing A Telephone Conversation, Thaddeus Gabara, Vladimir I. Prodanov

Electrical Engineering

Methods and apparatus are provided for preventing a third party from listening to a conversation between at least two participants on a telephone. The telephone generates an audio stimulus signal that is presented through a secondary speaker. The audio stimulus signal may be, for example, pseudorandom noise or a cancellation signal. According to one aspect of the invention, the telephone ensures that the audio stimulus signal does not significantly impair the conversation for the at least two participants. To prevent the third party from listening to the local portion of the conversation, the audio stimulus signal is subtracted from the ...


Dynamic Properties Of Railway Track And Its Components : A State-Of-The-Art Review, Sakdirat Kaewunruen, Alexander Remennikov Dec 2008

Dynamic Properties Of Railway Track And Its Components : A State-Of-The-Art Review, Sakdirat Kaewunruen, Alexander Remennikov

Faculty of Engineering - Papers (Archive)

Recent findings indicate one of major causes of damages, which is attributed to the resonant behaviours, in a railway track and its components. Basically, when a railway track is excited to generalised dynamic loading, the railway track deforms and then vibrates for certain duration. Dynamic responses of the railway track and its components are the key to evaluate the structural capacity of railway track and its components. If a dynamic loading resonates the railway track’s dynamic responses, its components tend to have the significant damage from excessive dynamic stresses. For example, a rail vibration could lead to defects in ...


Secondary Electron Imaging Of Embedded Defects In Carbon Nanofiber Via Interconnects, Makoto Suzuki, Yusuke Ominami, Takashi Sekiguchi, Cary Y. Yang Dec 2008

Secondary Electron Imaging Of Embedded Defects In Carbon Nanofiber Via Interconnects, Makoto Suzuki, Yusuke Ominami, Takashi Sekiguchi, Cary Y. Yang

Electrical Engineering

Carbon nanofiber (CNF) via interconnect test structures are fabricated with the bottom-up process proposed by Li et al. [Appl. Phys. Lett. 82, 2491 (2003)] for next-generation integrated circuit technology. Critical defects in the interconnect structure are examined using scanning electron microscopy. It is shown that secondary electron signal with optimized incident beam energy is useful for detecting embedded defects, including unexposed CNF plugs and voids in the dielectric layer. The defect imaging mechanisms are elucidated based on beam-induced charging of the specimen surface.