Engineering Commons^™

Characterization And Mapping Of Crystal Defects In Silicon Carbide, Ejiro Emorhokpor

Theses

Silicon carbide (SiC) is a semiconductor with attractive properties, such as a wide bandgap (3. 26 eV), high dielectric strength, and high thermal conductivity that make it suitable for high power, highspeed electronic devices. A major roadblock to its wider application is the presence of defects, particularly micropipes and dislocations, in SiC wafers produced today and decreasing density of these defects is the most important challenge of the industry. The goal of this thesis was to design, build and test a system for detection and analysis of the defects in SiC wafers. The system is based on the reflection optical …

Role Of Catalyst And Substrate In Synthesis Of Single Wall Carbon Nanotubes, Amit Goyal

Theses

The synthesis of single wall carbon nanotubes (SWNTs) by the catalyticdisproportionation of carbon monoxide (CO) (i.e., Boudouard reaction) at I atm pressureand 700-800 C, has been systematically investigated in order to determine whether theprocess can be used for the large scale production. SWNT diameter distribution andmorphology were studied by Raman scattering, and scanning and transmission electronmicroscopy, respectively. X-ray diffraction was used to determine levels of the remnantcatalyst and support. Synthesis experiments were conducted using a three-stage processwith hydrogen to reduce the catalyst-precursor and argon to cool the system. Two typesof catalyst/support synthesis were studied: (1) Combustion synthesis to form catalyst …

Fpga Implementation Of A Cholesky Algorithm For A Shared-Memory Multiprocessor Architecture, Satchidanand G. Haridas

Theses

Solving a system of linear equations is a key problem in the field of engineering and science. Matrix factorization is a key component of many methods used to solve such equations. However, the factorization process is very time consuming, so these problems have traditionally been targeted for parallel machines rather than sequential ones. Nevertheless, commercially available supercomputers are expensive and only large institutions have the resources to purchase them or use them. Hence, efforts are on to develop more affordable alternatives. This thesis presents one such approach.

The work presented here is an implementation of a parallel version of the …

Direct Simulation Of Electrorheological Suspensions Subjected To Pressure Driven Flow And Spatially Non-Uniform Electric Field, Arun Thankamony John Kadaksham

Theses

A numerical method based on the distributed Lagrange Multiplier method is developed for direct simulation of electrorheological (ER) suspensions subjected to pressure driven flows and spatially non-uniform electric fields. The flow inside particle boundaries is constrained to be rigid body motion by the distributed Lagrange multiplier method and the point-dipole approximation is used to model the electrostatic forces acting on the polarized particles. Simulations show that the particles move to the regions of high electric field when the value of β, the Clausius-Mossotti factor is positive and they move to the regions of low electric field when the value of …

Design Of An Fpga-Based Parallel Simd Machine For Power Flow Analysis, Tirupathi Rao Kunta

Theses

Power flow analysis consists of computationally intensive calculations on large matrices, consumes several hours of computational time, and has shown the need for the implementation of application-specific parallel machines. The potential of Single-Instruction stream Multiple-Data stream (SIMD) parallel architectures for efficient operations on large matrices has been demonstrated as seen in the case of many existing supercomputers. The unsuitability of existing parallel machines for low-cost power system applications, their long design cycles, and the difficulty in using them show the need for application-specific SIMI) machines. Advances in VLSI technology and Field-Programmable Gate-Arrays (FPGAs) enable the implementation of Custom Computing Machines …

Graphical User Interface For Improved Laser Eye Surgery, Venkata K. Kuruganti

Theses

This thesis develops a system for laser eye surgery that is a significant improvement over existing technology. The new system uses image matching and MEMS micromirrors to introduce feedback control, automation and record keeping to the laser surgery process, eliminating the unwanted effects of eye movement during surgery and introducing a wide range of other benefits. It is expected that this improvement can be implemented as an addition to existing systems as well as a foundation for new tools, perhaps even remote, internet enabled ones.

The basic components of the new system are described and demonstrated, including image matching between …

Detecting Malfunction In Wireless Sensor Networks, Pablito C. Lake

Theses

The objective of this thesis is to detect malfunctioning sensors in wireless sensor networks. The ability to detect abnormality is critical to the security of any sensor network. However, the ability to detect a faulty wireless sensor is not trivial. Controlled repeatable experiments are difficult in wireless channels. A Redhat Linux. 7.0 Wireless Emulation Dynamic Switch software was used to solve this problem.

Six nodes were configured with a node acting as a base station. The nodes were all part of a cell. This means that every node could communicate with all other nodes. A client-server program simulated the background …

Intrusion Detection System For Ad Hoc Mobile Networks Using Neighborhood Watch Theory, Ramani Rajagopalan

Theses

This study describes several experiments to simulate and study temperature sensor networks. The ultimate goal of this study is to accurately predict a temperature sensor failure in a sensor network, using Network Neighborhood Watch theory. Simulated temperature measurements are used to compare the results of accuracy, and quickness in detecting a failure in a malfunctioning sensor node. This is done by changing the intervals between temperature sampling, by considering different rates of temperature raise, as well as varying the number of nodes in the network neighborhood (deployment density). The thesis studies the threshold for temperature sensor failure by computing a …

Comparative Studies Of Network Traffic In Actual And Emulated Wireless Networks, Curtis Salley Jr.

Theses

Wireless networks are becoming more popular in all types of environments from home office, to business infrastructure, to mobile computing. As more of these networks flourish, so does the attraction for hackers. The thesis examines the bandwidth of wireless networks and the effects of intrusions in three different scenarios. First, it looks at a wireless network that is connected to a wired infrastructure. Next, the thesis examines a wireless ad hoc network and how bandwidth plays a valuable part in the communication with neighboring nodes. And finally, the thesis attempts to simulate a wireless network by using a bandwidth configuration …

Reduction Of False Positives In Fault Detection System Using A Low Pass Data Filter, Ranjit Salunkhe

Theses

Network traffic is bursty in nature and exhibits the property of self-similarity, the degree of which is measured by the Hurst parameter. Now, in any network there is always the possibility of the occurrence of fault traffic that can be caused due to faults or malfunction of a network component. Fault Detection Systems that check for traffic anomalies can trigger off an alert on the detection of any traffic behavior that deviates from normal. Such deviation is usually caused when a fault occurs. But in network traffic sudden bursts may occur due to the inherent behavior of a network application. …

Sub-Segment Based Transport Layer Protocol For Wireless Medium, Som Sengupta

Theses

This thesis discusses the techniques to improve the TCP over wireless. The loss-intensive wireless communication results in high retransmission rates to recover lost packets and bandwidth consumption. In addition, the retransmitted segments have significant chance of being dropped. To make the retransmission process more granular, large segments at the transport layer (540 bytes, by default) can be subdivided into smaller sub-segments. This document introduces a split TCP based solution and describes how to produce a series of smaller-sized segments that share the same transport layer header. A new header format is introduced to support the transmission of smaller segments …

Low-Power Transceiver Design For Mobile Wireless Chemical Biological Sensors, Harshavardhan Reddy Sripuram

Theses

The design of a smart integrated chemical sensor system that will enhance sensor performance and compatibility to Ad hoc network architecture remains a challenge. This work involves the design of a Transceiver for a mobile chemical sensor. The transceiver design integrates all building blocks on-chip, including a low-noise amplifier with an input-matching network, a Voltage Controlled Oscillator with injection locking, Gilbert cell mixers, and a Class E Power amplifier making it as a single-chip transceiver. This proposed low power 2GHz transceiver has been designed in TSMC 0.35~lm CMOS process using Cadence electronic design automation tools. Post layout HSPICE simulation indicates …

Analysis Of Random Packing Of Uniform Spheres Using The Monte Carlo Simulation Method, Sai S. Tulluri

Theses

The study of random packing of spheres has had a long history. It particularly interests many researchers because randomly packed hard spheres exhibit some features of the properties of simple liquid, e.g. the packing density and the radial distribution. Many researchers have studied random packing both experimentally and also by using computer simulation.

Monte Carlo simulation method was used to generate random loose packing of hard spheres. Packing characteristics like packing density, radial distribution function, co-ordination, angular distribution and fabric tensor have been computed for this packing system.

The packing density for a system of 8000 particles with a diameter …

Addition Of A Chain-Cell Search Method And A Van Der Waals Force Model To A Particle Dynamics Code, Michael J. Sweetman

Theses

This project studies the implementation of a computational time saving technique and adds an additional force model into a discrete element method simulation code. Both aspects of the project are focused on increasing the versatility of an existing particle dynamics code by increasing the execution speed and available force models for simulation.

The first portion of the project consisted of adding a function to the collision detection mechanism to hash the particles into a spatial grid. This hashing function allows a search for near neighbor particles to be restricted to the space immediately adjacent to the particle of interest, thereby …

Design And Evaluation Of Processes For Fuel Fabrication: Quarterly Progress Report #7, Georg F. Mauer

Fuels Campaign (TRP)

The seventh quarter of the project covered the following:

• Mr. Richard Silva continued the development of a simulation model with a Waelischmiller hot cell robot. Rich will continue to develop detailed 3-D process simulation models as his M.Sc. thesis project.

• Mr. Richard Silva presented a paper on hot cell robotics at the ANS student conference in Berkeley, CA.

• Concepts and Methods for Vision-Based Hot Cell Supervision and control, focusing on rule-based object recognition (Ph.D. Student Jae-Kyu Lee)

• Undergraduate student Jamil Renno, developed better control algorithms, and created simulations of pick and place actions for the hot …

Soft Fault Detection Using Mibs In Computer Networks, Sachin Arora

Theses

To improve network reliability and management in today's high-speed communication system, a statistical anomaly network intrusion detection system (NIDS) has been investigated, for network soft faults using the Management Information Base (Mm) traffic parameters provided by Simple Network Management Protocol (SNMP), for both wired and wireless networks. The work done would be a contribution to a system to be designed MIB Anomaly Intrusion Detection, a hierarchical multi-tier and multiobservation-window Anomaly Intrusion Detection system. The data was derived from many experiments that had been carried out in the test bed that monitored 27 MIB traffic parameters simultaneously, focusing on the soft …

Optimization Of Very Early Strength Concrete Mixes Using Maturity Method, Sun Punurai

Theses

Fast track concrete technology has been used over the past two decades for overnight highway repairs. Originally, fast track was concerned only with rapid strength gain and workability but little concern was paid to cost and durability of the concrete.

The purpose of this research study is to develop a current improved very early strength (VES) concrete mix, which was accepted by NJDOT in 1996. More than 50 concrete mixes were evaluated for strength, shrinkage, and curing rate (maturity), eventually leading to the development of an optimized VES concrete mix with improved performance characteristics.

The study has developed the new …

Tracking The Path Of A Mobile Radioactive Source Using A Wireless Sensor Network, Nipa Shah

Theses

This report describes several experiments used to characterize and test a network of radiation sensors. The purpose of these tests is to assess the feasibility of using these sensors to detect and track radioactive sources in a large field, as in a battlefield or on a military campus. Simulated radiation measurements are used to compare the result of radiation detection accuracy in tracking the moving target and to find its path as early as possible. This is done via changing the number of sensing nodes deployed (deployment density), as well as the models of the detectors. This thesis describes algorithms …

Process-Structure-Property Relationship Of A Mesogenic Bioerodible Polyarylate, Seung Uk Yoo

Theses

Polymeric biomaterials are artificially synthesized polymers designed for in-vivo use. The material must be characterized and should satisfy the requirements suitable in human bodies.

For the proper characterization of materials, it is essential to apply specific processes, analyze thermal and mechanical properties, and understand the process effect and the morphology. Thermal analysis is one of the most sophisticated and well developed techniques for polymer characterization. Turi [ 1 ] has explained about the thermal characterization of polymeric materials. Jaffe et al [2], in the chapters of characterization of fibers and films, emphasized the effect of the process history of a …

Modification Of Biodegradable Polyesters With Inorganic Fillers, Georgia Chouzouri

Theses

In attempts to address the growing need of materials with controlled degradation characteristics and good mechanical properties for tissue engineering applications, composites based on biodegradable polymers and a potentially bioactive novel inorganic synthetic filler were produced and characterized. Composites were produced by solution mixing of a commercial polylactic acid, as well as a biodegradable thermoplastic polyester based on butylene adipate/succinate, with synthetic magnesium/aluminum carbonate minerals, known as hydrotalcites. Two types of hydrotalcites, at 30 wto/o filler level, were used: surface coated and uncoated. Composites were also melt-mixed in a twin-screw extruder for comparison.

Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), …

Data Recording And Analysis Of American Sign Language, Robert Michael Demarco

Theses

American Sign Language (ASL) is a form of communication that is used by the Deaf. It consists of hand shapes and gestures to express words and phrases. Translators on the market today consist of interpreting a simple form of ASL known as finger spelling. In order to develop a more effective translator, instrumentation was developed utilizing a Flock of Birds and Cyberglove system to record in hand shapes and movements in a LabVIEW environment. Experimentation done included reading in data and subjectively analyzing the data recorded for accuracy. Initial results have show that the instrumentation worked and data was recorded …

Sparse Matrix Product Implementation On Field Programmable Gate Arrays (Epgas), Amit Mahendra Sheth

Theses

If dense matrix multiplication algorithms are used with sparse matrices, they can result in a large number of redundant calculations, as numerous elements in sparse matrices are zero valued, thus available resources and time may be wasted. The algorithm discussed here aims to take advantage of the sparseness of the matrices by multiplying only nonzero elements.

The NIOS development board from Altera is used for implementing the above algorithm. First a sequential program in the C programming language is downloaded onto the FPGA and run by the NIOS soft-processor. Then the same board is also used for a parallel implementation …

Implementation Of Cyclic Exercise Protocol On Two Study Groups - Aids And Insomnia, Ujwala G. Kalambur

Theses

Traditional exercise regimens are based on maintaining a prolonged increase in heart rate, followed by a single recovery period. The Cyclic Exercise Protocol is a novel protocol that is designed to create a series of parabolic waves of exercise and recovery. This study involves the implementation of this exercise protocol on two study groups namely AIDS and Insomnia. This exercise protocol involves short bursts of exercise lasting for 60 seconds or less followed by a period of complete aerobic recovery. The underlying principle of this exercise protocol is that rest, recovery and the body's natural rhythm are important to fitness …

Discrete Element Simulation And Nonlinear Dynamic Analysis Of Particles In A Simple Lattice Structure, Liam E. Buckley

Theses

The study of particles interacting in lattice structures allows for insight into the complex interactions of granular flow, and the adaptation of such structures to mechanical apparatuses to handle the separation of bulk particulate matter. Applying methods of computer analysis to the interactions taking place within the particle-lattice system provides a particle level methodology to the study of the phenomenon taking place, as well as a stepping stone for future design of related devices.

A two prong approach is presented to the study of such particle-lattice systems. The first approach is composed of adapting an existing discrete element computer code …

Ferromagnetic Domain-Wall Behavior During Reversal And Thermally Activated Antiferromagnetic Reversal In An Exchange-Biased Nio/Nife Bilayer, Z. Y. Liu, Shireen Adenwalla

Materials Research Science and Engineering Center: Faculty Publications

The magnetization reversal mechanism in an exchange-biased NiO/Ni₈₁Fe₁₉ bilayer has been investigated using the magneto-optic Kerr effect and magnetic force microscopy imaging. The asymmetric reversal along the unidirectional axis and the two-step reversal process along the hard axis are promoted by ferromagnetic domain-wall behavior in the decreasing and increasing field branches of the as-deposited hysteresis loop, which is strongly related to the exchange coupling at the interface and the distribution of orientation of the net magnetization at the interface carried by the antiferromagnetic domains. The temperature dependence of the exchange bias and coercivity shows the thermally activated …

Observation Of Novel Liquid-Crystalline Phase Above The Bulk-Melting Temperature, Keshav S. Gautam, Satyendra Kumar, Didier Wermeille, Doug Robinson, Ali Dhinojwala

College of Polymer Science and Polymer Engineering

In this paper, we show that a noncrystalline but ordered smectic-like phase exists above the bulk-melting temperature (T-m) at poly(n-alkyl acrylates)-air interface. The surface ordered phase is one monolayer thick and undergoes a sharp transition from order to disorder 10degreesC above T-m for n=22. The presence of a surface phase that does not exist in the bulk has important implications in the design of thermally responsive adhesives.

Polar Sea Ice Mapping For Seawinds, Hyrum Spencer Anderson

Theses and Dissertations

In recent years, the scientific community has expressed interest in the ability to observe global climate indicators such as polar sea ice. Advances in microwave remote sensing technology have allowed a large-scale and detailed study of sea ice characteristics. This thesis provides the analysis and development of sea ice mapping algorithms for the SeaWinds scatterometer. First, an in-depth analysis of the Remund Long (RL) algorithm for SeaWinds is performed. From this study, several improvements are made to the RL algorithm which enhance its performance. In addition, a new method for automated polar sea ice mapping is developed for the SeaWinds …

High Resolution Wind Retrieval For Seawinds On Quikscat, Jeremy Blaine Luke

Theses and Dissertations

An algorithm has been developed that enables improved the resolution wind estimates from SeaWinds data. This thesis presents the development of three key portions of the high resolution wind retrieval algorithm: Compositing individual σ-0 measurements and Kp, Retrieved wind bias correction, and ambiguity selection for high resolution winds. The high resolution winds produced by this algorithm are expected to become a useful resource for scientists and engineers studying the ocean winds. The high resolution wind retrieval algorithm allows wind to be retrieved much closer to land than is available from the low resolution winds estimated from the same scatterometer by …

Study Of Marine Biocorrosion Using Afm And Molecular Techniques, Herbert H.P.Fang, Lichong Xu, Tong Zhang

Journal of Electrochemistry

Biofilm is ubiquitous in nature.However,corrosin caused by biofilm is still by and large overlooked. This presentation is to demonstrate the applications of several newly developed analytical techniques in chemisrty and microbiology for the study of marine biocorrosion on steel. AFM(atomic force microscopy) was applied to investigate the initial formation mechanism of biofilm and the degree of corrosion of steel in polluted seawater. DNA/RNA-related molecular techniques were used to analyze the microbial composition corrosive biofilm. Results showed that microbial corrosion began within six days, and the corroded volume in the increased as a power function of time with an index 2.83. …

A Bilayer Self-Assembled Membrane Electrode For Fluorescence And Its Electrochemical Characterization, Xiang-Ying Sun, Bin Liu, Yun-Bao Jiang

Journal of Electrochemistry

The bilayer membrane was assemblied on Au electrode by the electrostatic interaction between the fluorescence regent 1-naphthylamine diacetate acid (NADA) and DL-Cysteine. The SAMs electrode NADA/Cys/Au can be used as fluorescence and electrochemical sensor for metal ions. This paper states the electrochemical characterization of NADA/Cys/Au and SAMs' application in continous determination for Cu²⁺ and Ni²⁺.