Engineering Commons^™

Investigation Of The Band Structures And Optical Properties Of Super Lattices, Sheikha Ahmed Awad Alnaeme

Theses

Group III nitrides are highly attractive materials because of their great potential for the development of optoelectronic devices in short wavelength, semiconductor lasers and optical light-emitters and detectors. GaN, AlN and InN are considered as the most important compounds in this class of materials. In this work, we present a theoretical investigation of the electronic properties (band structure, density of state and contour maps of the charge density distribution) and optical properties (refractive index, absorption and dielectric constants). Also, we investigate the band structures and optical properties of AlN/GaN and InN/GaN super lattices. A full-potential linearized plane-wave (FPLAPW) method is …

A Wireless Method For Monitoring Medication Compliance, Jeffrey Scott Jonas

Theses

There are many devices on the market to help remind patients to take their pills, but most require observation by a caregiver to assure medication compliance. This project demonstrates three modes to detect pill removal from a pillbox: a switch under the pills, a reflective type photointerrupter and a transmissive "electric eye" photosensor. Each mode exhibited blind spots or other failures to detect pill presence, but by combining modes with complementary characteristics, the accuracy of pill detection is greatly increased.

Two methods of caregiver notification are demonstrated: text messages transmitted via an attached cellular phone, or the status is collected …

Individual Cell Pressure Control In An Air Mattress For The Prevention Of The Pressure Sores, Kapilchandra Anand

Theses

Many kinds of pressure-relieving mattresses have been developed to prevent pressure sores in patients with spinal cord injuries (SCIs) and obesity. Current technology uses alternating air pressure mattress, foam and low pressure mattress for reducing the incidence of pressure sores in SCI and obesity patients. These mattresses do not have control of pressure in individual air chambers. They are open loop system and they do not receive any feedback from the system. They have at the most control of two different pressures. The purpose of this study is to improve the current assistive technology in reducing pressure sores and to …

Characterization Of Thermally Diffused Bordie Layers On Aisi 1018 Steel : Residual Stresses (By Synchrotron Radiation) And Microhardness, Joel A. Payne

Theses

Boronization is a thermal diffusion process in which needle like boride layers are formed at the surface of the metallic substrate. The boride coatings formed by the diffusion process have high hardness and strong ware and corrosion resistance. In order for coatings of this nature to be industrially successful, their service life should be long and characterization should be extensive. Measuring the residual stresses of the coatings caters to each of these aspects.

In this study, AISI 1018 steel samples were boronized by a powder-pack process for four hours at 850°C in an argon atmosphere. Characterization techniques included coating thickness, …

Dem Simulated Floor Pressure Induced By A Granular Column, Shawn A. Chester

Theses

At the end of the 19th century, H. A. Janssen discovered that the bottom floor pressure in a cylindrical container of granular material asymptotes exponentially to a value less than the weight of the material i.e., the pressure becomes independent of the fill height of the column. This phenomenon is investigated using discrete element simulations of inelastic, frictional spheres in a cylindrical vessel having a particle-to-cylinder diameter ratio at approximately 13.3 or 26.6, with varying bed heights in both cases. The axial pressure profile and the load experienced by a piston that is supporting the granular column are computed. In …

In-Vitro Characterization Of Boronized Titanium Alloy By Means Of Corrosion And Electrochemical Impedance Spectroscopy Methods In Simulated Body Fluids, David Anthony Panus

Theses

Titanium and titanium alloys are becoming the backbone of medical implants and prosthetics. Titanium alloys are used because of its high biocompatibility and similarity to bone. However, titanium and titanium alloys have a low wear resistance. Titanium and titanium alloys are susceptible to particle erosion, which can cause inflammation, infection, and even implant rejection. Boronizing titanium alloy improves titanium's wear resistance and also improves corrosion resistance.

The target of this research was to characterize the corrosion characteristics of both unboronized and boronized titanium using both electrochemical corrosion methods and Electrochemical Impedance Spectroscopy (ELS) in simulated body fluid. Using electrochemical methods …

Fabrication And Characterization Of Back Illuminated Cmos Photodiode Array, Amitra Banerjee

Theses

With the rapid development in low-cost CMOS technology, silicon photodiodes are currently recognized as promising choice for the imager core. In this research, the arrays of back illuminated photodiodes were designed, fabricated and demonstrated with CMOS imager fabrication process on silicon wafers. The main purpose of this work was to improve the contribution of these arrays on the imaging systems before committing their design on the chips.

In this CMOS process, first the n-well, p-well, n+and p+ regions were simulated and fabricated by several implantation processes. The n-well region was implanted by phosphorus at an energy of 170 keV and …

Fpga-Based Implementation Of Parallel Graph Partitioning, Mohammad Kharashgeh

Theses

Graph partitioning is a very important application that can be found in numerous areas, from finite element methods to data processing and VLSI circuit design. Many algorithms have been developed to solve this problem. Of special interest is multilevel graph partitioning that provides a very efficient solution. This method can also be parallelized and implemented on various multiprocessor architectures. Unfortunately, the target of such implementations is often unavailable high-end multiprocessor systems. Here a parallel version of this method for an in-house developed multiprocessor system is implemented on an FPGA. The system designed provides a cost-effective solution.

The design is based …

Fabrication Of Hydroxyapatite-Biodegradable Polymer Scaffolds By Electrospinning For Potential Bone Tissue Application, Satomi Suzuki

Theses

The purpose of this study is to determine the potential of combining hydroxyapatite (HA) and polymers to form synthetic composite materials used for bone tissue engineering applications. In this study, ceramic-biodegradable polymer composites are fabricated by electrospinning method. The biodegradable polymers used are poly(L-lactic acid) (PLLA), and poly(lactide-co-glycolide) (PLGA). Two types of HA-polymer solutions are first prepared to achieve HA weight percentage of 0, 10, and 25%of the total combined weight of HA and PLLA, and HA and PLGA. The solutions are electrospun to form nanofibrous mats incorporated with HA powder. A biomimetic process was also conducted as a …

Submicron Patterning Using Laser Interference Lithography, Luigi Pollara Verdoni

Theses

In this thesis, the theory, fabrication protocol, and initial results of an alternative nanopatterning technique called Interferometric Lithography (IL) are presented. Comprised of the identical process attributes of traditional projection photolithography, IL mirrors the wafer preparation and development procedures of our existing clean room capabilities. The main departure is solely in means of pattern delineation. IL is a "mask less" technique that employs the interference fringe pattern of two coherent beams, and can therefore be generated with a commercial laser. Due to its simplicity, Interferometric Lithography provides an attractive supplement to existing methods of nano-patterning.

Utilizing a 325 nm HeCd …

The Effect Of Sample Size And Ground Granulated Blast-Furnace Slag On Hydration Temperature In Hot Climates, Mariam Eissa Saeed Al-Harrasi

Theses

Heat of hydration of Portland cement mixes is of great importance to civil engineers. While there is great deal of work being carried out on the hydration temperature of OPC-slag mixes, there is a lack in the literature of research work on the effect of such materials in real hot climates. The current research examines the influence of ground granulated blast-furnace slag (ggbs) as a partial cement replacement on temperature evolution during hydration in winter and summer in AI-Ain (interior region of the United Arab Emirates). Evolution of temperature inside the concrete was recorded by the aid of a Labview …

Dry Magnetic Assisted Impaction Mixing Of Sub-Micron Boron And Barium Chromate For A Time Delay Composition, Ryan Barrow

Theses

The objective of this investigation is to improve the mixture homogeneity of, Boron and Barium Chromate, a delay composition called T-10, using a novel dry mixing technique, , called the Magnetic Assisted Impaction Mixing (MAIM). Two additional mixing methods, ultra-sonic mixing and shaker mixing (dry and wet), were used for comparative analysis, to evaluate the mixing effectiveness of the MAIM which was also compared to two Navy mixed T-l0 samples. Characterization of the homogeneity is described by how well boron is effectively distributed throughout the mixture, which is a challenging task since the mixture's composition is 3% Boron versus 97% …

Osteogenic Differentiation Of Human Mesenchymal Stem Cells On Thin Film Tyrosine Derived Polycarbonates, Tamunotoyne Briggs

Theses

Mesenchymal stem cells, harvested from adult bone marrow, are promising in the field of regenerative medicine because of the vast differentiation potential into various cell lines such as: osteoblasts, chondrocytes, adipocytes, and neurons. Osteogenic differentiation of human mesenchymal stem cells (hMSC) could be an important tool in the treatment of orthopedic deficiencies such as bone defects. The extent of in vitro human mesenchymal stem cell growth, adhesion, motility and differentiation into osteoblasts is a function of the material surface chemistry which is mediated by protein adsorption onto the surface. A library of tyrosine derived polycarbonates allows the tailoring of material …

Auto Detection In Autism, Gayathri Chandar

Theses

Autism is a neurobiological disorder in which, certain regions of the brain are affected. The main features of autism are impairment in communication, social interaction, language and deficit in imitation and theory of mind. Using Functional Magnetic Resonance Imaging (fMRI), haemodynamic responses during a bilateral finger tapping task are analyzed for both autistic subjects and normal control subjects. fMRI is a noninvasive technique to image the activity of the brain related to a specific task. Generally, the active voxels in the IMRI images are detected using parametric or non-parametric statistical methods in which the fMRI response is assumed to have …

Classification, Testing And Optimization Of Intrusion Detection Systems, Javier Leon

Theses

Modem network security products vary greatly in their underlying technology and architecture. Since the introduction of intrusion detection decades ago, intrusion detection technologies have continued to evolve rapidly. This rapid change has led to the introduction of a wealth of security devices, technologies and algorithms that perform functions originally associated with intrusion detection systems.

This thesis offers an analysis of intrusion detection technologies, proposing a new classification system for intrusion detection systems. Working closely with the development of a new intrusion detection product, this thesis introduces a method of testing related technologies in a production environment by outlining and executing …

Pda Based Ambulatory Pulse Oximeter, Arpita Shah

Theses

The main aim of the research was to develop an ambulatory pulse oximeter which can be used to monitor the SpO₂ heart rate (HR) and plethsymograph (PPG) waveform of a person. To achieve this, an algorithm was developed in LabVIEW 8.0 to extract the HR, SpO₂ and PPG data from a Nonin Xpod device, Nonin Medical, Inc. LabVIEW PDA software was developed to make it compatible with the PDA. LabVIEW software was also developed for sending the data to the PDA via Bluetooth Pulse Oximeter commercialized by Nonin Medical Company.

Using this algorithm, data was collected from three …

Performance Analysis Of Collaborative Hybrid-Arq Protocols Over Fading Channels, Igor Stanojev

Theses

Impairments due to multipath signal propagation on the performance of wireless communications systems can be efficiently mitigated with time, frequency or spatial diversity. To exploit spatial diversity, multiple-antenna technology has been thoroughly investigated and emerged as one of the most mature communications areas. However, the need for smaller user terminals, which results in insufficient spacing for antenna collocation, tends to limit the practical implementation of this technology. Without compromising terminal dimensions, future wireless networks will therefore have to exploit their broadcast nature and rely on collaboration between single-antenna terminals for exploiting spatial diversity.

Among cooperative schemes, Collaborative ARQ transmission protocols, …

The Complex Behavior Of Poly(Dte) Carbonate And Its Blend Properties, Christopher George Elvin

Theses

Over the years a number of different polymers have been studied for bone applications. Polyesters such as the poly lactic acids (PLA), poly glycolic acids (PGA), and their copolymers have been studied intensely for bone regeneration purposes. Poly(DTE)carbonate has been found useful for bone regenerative purposes and is under review by the U.S. Food and Drug Administration.

The purpose of this study was to investigate the properties of poly(DTE)carbonate when PLLA, PLGA, and P(LcoDL)LA was blended with it. The desired outcome was to produce miscible polymer blends or significant phase shift in the blended materials which will make them at …

Automatic Detection Of Qt And Related Intervals, Divya Gowdar

Theses

The objective of this thesis is divided into two main sections: The first section comprises of the development of the algorithm for the detection of the Q wave, Tmax afld the Tend to measure the intervals such as QT, QT corrected (QTc), RT, QT_max and RT_max respectively. The second section deals with the analysis of different variabilities including heart rate variability (HRV), QT, QTc, RT, QT_max and RT_max.

Using the R wave points as reference points, the Q wave was detected by using the Differential Threshold Method (DTH). The Tmax was detected by using a …

Location Estimation In A 3d Environment Using Radio Frequency Identification Tags, Adwitiya Akash Jain

Theses

RFID tag location estimation in a 3D environment is investigated. The location of the tag with unknown coordinates can be estimated with certain accuracy. However, accuracy can be improved using the knowledge based on measurement of additional reference tags with known location. This thesis studies the mathematical formulation and practical realization of location sensing using RFID tags.

Deviating from the standard use of RFID technology which employs one tag reader to identify the presence of tag, here multiple tag readers with known location are used to estimate the physical location of an individual tag, with/without the help of few reference …

Fabrication Of Aligned Nanofiber Yarns, Mats And Isolation Of Single Nanofiber In Electrospinning, Venkatesh T. Nathilvar

Theses

Electrospinning has been extensively used as an effective technique for the fabrication of submicron and nanometer scale polymeric fibers. In spite of technological advances in electrospinning, creating a highly aligned fiber structure is a tough target to be achieved because of the chaotic motion of the electrospinning jet. In this study, two different techniques have been adopted to form a highly aligned nanofibrous scaffolds. Using these methods highly aligned fiber yams and mats are produced from Cellulose Acetate (CA) in a mixed solvent of acetone and water. In both the techniques the nanofibers suspend over the gap in a highly …

Development Of A System To Measure Cardiac Function In The Drosophila Melanogaster Animal Model, Heather Anne Reinhardt

Theses

Previous studies have shown that several genes are evolutionarily conserved from lower organisms to man, where a number of genes have been directly linked to cardiac function and disease. The Drosophila melanogaster (Fruit Fly) has a genome similar to humans and therefore has proven to be an important animal model to study the role of genetics in cardiac function and disease development. Fruit flies are an important basic science model because of the ease with which genes can be manipulated and quickly expressed due to the short lifespan of the fly. Although standard techniques exist to affect the genome of …

New Hybrid Automatic Repeat Request (Harq) Scheme For 4x4 Mimo System, Based On The Extended Alamouti Quasi-Orthogonal Space-Time Bloc Coding (Q-Stbc), In Invariant And Variant Fading Channel, Jordi Ferrer Torras

Theses

A new Hybrid Automatic Repeat reQuest (HARQ) combining scheme for a 4x4 Multiple Input Multiple Output (MIMO) system in invariant and variant fading channel conditions is proposed and analized. Based on the Extended Alamouti Quasi-orthogonal Space-Time Block Coding (Q-STBC), the use of the so-called Alternative Matrices for transmission, depending on the Channel State Information (CSI) received as feedback, is compared to other existing solutions.

Sign changes and permutations in the retransmission sequences allow reducing the interference while exploiting the spatial diversity to introduce some gain in the signal power. The best transmission order is selected by the Determinant Criterion, which …

Synthesis Of Polymeric Nanocomposites In Supercritical Carbon Dioxide, Hongta Yang

Theses

Supereritical carbon dioxide has been of great interest in various areas of chemical science and engineering during the last decade. In this thesis, the properties of poly (methyl methacrylate) (PMMA)/silica nanocomposites with different surfactant and filler concentrations synthesized through in-situ polymerization in supercritical carbon dioxide were investigated. In addition, ferromagnetic nano-particles were synthesized and functionalized for the preparation of nanocomposites. The thermal stability and surface morphology of PMMA/iron oxide nanocomposites synthesized in supercritical carbon dioxide were first studied in the work.

The scanning electron microscopy micrographs show that higher surfactant concentration results in higher number density of polymeric nanocomposite particles …

New Hybrid Automatic Repeat Request (Harq) Combining With Space Time Block Coding (Stbc) In Invariant And Variant Fading Channel, Guillem Ernest Malagarriga Vilella

Theses

Hybrid Automatic Repeat reQuest (HARQ) combining for space time block coding Multiple Input Multiple Output (MIMO) system consisting of N transmit antennas and M receive antennas (NxM) in a time invariant channel and in a time varying channel is proposed and its performance is analyzed. Based on the measured channel matrix, the receiver chooses the best retransmission order and communicated it to the transmitter.

The scheme, where this algorithm is performed, is a combination of a precombining HARQ scheme and the Multiple Alamouti Space-Time Block Coding (MASTBC), which is suitable for more than 2 transmit antennas. The combination of this …

A Study Of Steganography And Steganalysis, Nisant Nalla

Theses

Steganography is the art of hiding the fact that communication is taking place, by hiding information in other information. Steganalysis is the study of methods to detect the presence of hidden messages. The Steganography and Steganalysis are very much interdependent. The people in the Steganography domain try to develop stronger methods to hide data in different media. This spurs the discovery of new steganalysis methods which can break these Steganography methods. This is vital for the development of these fields. The internet has been growing by leaps and bounds. There is an increasing need for information security. It has been …

Boron Induced Surface Modification Of Transition Metals, Raghasudha Vangaveti

Theses

Boronizing is a thermo-chemical surface treatment of metals in which boron atoms diffuse into the metal substrate and form hard metallic borides. As a result of boronizing, several properties such as hardness, wear resistance, corrosion resistance, and high temperature oxidation resistance improve which make the metal substrate more suitable for industrial applications. These boronized parts are used in many industrial applications like ingot moulds, crucibles, biomedical implants, die-casting moulds, magnetic head applications, drawing dies etc.

The objective of this work was to investigate the influence of boronizing on the properties of transition metals. Three transition metals, tantalum, niobium and tungsten …

Medical Equipment Planning And Construction Of A Interventional Neuroradiology Suite, Furqan Elahi

Theses

New York-Presbyterian Hospital is one of the most comprehensive university hospitals in the world, with leading specialists in every field of medicine. It is composed of two renowned medical centers, New York-Presbyterian Hospital/Columbia University Medical Center and New York-Presbyterian Hospital/Weill Cornell Medical Center. The hospital's strategic planning group identified the need to expand the Interventional Neuroradiology service that the hospital provides. This brought upon the need to form a committee to plan the construction of an Interventional Neuroradiology. The problem statement of this thesis is to prepare a best practices guideline from a clinical engineering perspective on constructing the three …

Modification Of Clays With Ionic Liquids For Polymer Nanocomponents, Neung Hyun Kim

Theses

In attempts to prepare nanofillers with enhanced compatibility with a polymer matrix, cationic and anionic clays susceptible to exchange of their interlamellar ions with a variety of other cations or anions, were selected.

In order to treat cationic clay, montmorillonite, which contains sodium ions as interlayer ions, reagents having cations differing in size and structure included three ionic liquids ([EMIM]⁺ [Br]^-, [HXMIM]⁺ [Cl]^-, and [Epty]⁺ [BF4]^-). Results indicated that cationic exchange did occur from aqueous solution as confirmed by FTIR, EDX, WAXS, TGA, and elemental analysis. WAXS indicated a significant increase …

Doppler Ultrasound Technique Used To Determine The Blood Flow Viscosity In The Middle Cerebral Artery Of A Canine Animal Model, Raj P. Ganpath

Theses

The cerebral blood flow velocity in the middle cerebral artery of an canine animal model was measured using the Doppler Ultrasound technique. A transducer was designed with a 20 MHz piezoelectric crystal and used for the application. An in vitro calibration system was designed and machined for the purpose of testing and calibrating every transducer before using it in vivo. Preliminary tests included experiments on the in vitro system and measurement of blood flow velocity in the human wrist artery (metacarpal artery). The effect of using different transmission media (agarose and gelatin) was determined through the many in vitro and …