Engineering Commons^™

Characterization Of Mechanical Behavior Of Electrospun Non-Woven Mats, Ajitha Patlolla

Theses

Electrospinning is a simple and efficient method for the production of nanometer to micrometer fibers. While the process of electrospinning has been known for over half a century, current understanding of the process and those parameters that affect the properties of the fibers is very limited. Not much work has been done in the field electrospinning process to study the mechanical properties of nonwoven mats produced and to study parameters affecting their properties.

In the first part of this thesis electrospun nonwoven mats made of poly(lactides) solutions were characterized based on their mechanical behavior in biorelevant conditions. In the second …

Thermal Analysis Of Poly(Desamino Arylates), Ali Cem Recber

Theses

The goal of this study is to better understand the thermal characteristics and molecular behavior of two poly(desaminotyrosyl arylates). These two polymers were chosen from a combinatorial library of polymers developed by changing the type and size of the two substitutable chain locations. TGA, DSC and TSC studies were conducted on Poly(12,10) and Poly(2,2) after the samples were exposed to various conditions. The TGA of Poly(12,10) shows low water uptake at 25° C, higher water uptake at 80°C. Water uptake for Poly(2,2) at 25°C is similar to Poly(12,10) at 80°C. The Thermally Stimulated Current analysis (TSC) results indicate a molecular …

Parametric Synthesis Of Sign Language, Jerome Allen

Theses

The isolation of the deaf community from mainstream society is in part due to the lack of knowledge most hearing people have of sign language. To most, there seems to be little need to learn a language that is spoken by such a small minority unless perhaps a relative is unable to hear. Even with a desire to learn, the task may seem insurmountable due to the unique formational and grammatical rules of the language.

This linguistic rift has led to the call for an automatic translation system with the ability to take voice or written text as input and …

Mathematical Modeling And Simulation Of Human Motion Using 3-Dimensional, Multi-Segment Coupled Pendulum System : Derivation Of A Generalized Formula For Equations Of Motion, Loay Ahmed-Wasfe Al-Zube

Theses

The use of mathematical models to investigate the dynamics of human movement relies on two approaches: forward dynamics and inverse dynamics. In this investigation a new modeling approach called the Boundary Method is outlined. This method addresses some of the disadvantages of both the forward and the inverse approach. The method yields as output both a set of potential movement solutions to a given motor task and the net muscular impulses required to produce those movements. The input to the boundary method is a finite and adjustable number of critical target body configurations. In each phase of the motion that …

Application Of Bootstrap Resampling In Fmri, Arthika Bappal

Theses

This thesis demonstrates the use of the bootstrap resampling technique considering temporal dependency in the fMRI data to determine the reliability and confidence interval of fMRI parameters. Traditionally, the test-retest method has been used to reliably detect active voxels in the fMRI image of the brain, which is based on repetitive experimentation. The main concern with the test-retest method is the reproducibility of data over these multiple repetitions. Fatigue, habituation, motion artifacts, and repositioning errors are few of the factors, which can affect the reproducibility of data.

The conventional bootstrap resampling technique is based on the assumption that the dataset …

An Investigation Of Position And Force During Gait-Mimicking Finger Motions, Matthew Stephen Noesner

Theses

Spinal cord injuries are extremely debilitating, often leaving the injured person without the ability to use their legs (paraplegia) and sometimes, without the ability to use their arms and legs (tetraplegia or quadriplegia). Currently, primitive forms of feed-forward functional electrical stimulation (FES) and special orthotics are available for persons with paraplegia. However, these forms of FES do not allow the individual to actually control their movements on a real-time basis, nor do they offer the ability for the injured person to sense the ground on which they stand.

It is the goal of the researchers at the Neuromuscular Engineering Laboratory, …

Evaluation Of Effect Of Extrusion Process Variables On Mechanical Properties Of Extruded Collagen Tubes And Effect Of Post Extrusion Treatments, Mayank K. Patel

Theses

This study evaluated the effect of extrusion process variable on mechanical properties of extruded collagen tubes made using a specialized extruder, made by ZOKO Corporation of Czechoslovakia. Three extrusion variables were considered; extrusion speed, linear draw rate and rotation speed. Using Taguchi L₄ matrix, a design of experiment (DOE) was run. Two mechanical properties, wall thickness and estimated elastic modulus, were considered as response of this DOE. Data was analyzed statically to evaluate the effect of extrusion variables on both these properties. Result of this study showed that linear draw rate of the extrusion process has the highest influence …

Fabrication Of Nanofiber Scaffolds By Electrospinning And It's Potential For Tissue Engineering, Shobana Shanmugasundaram

Theses

Electrospinning is a fabrication process that uses an electric field to control the deposition of polymer fibers on to a target substrate. This electrospinning strategy can be used to fabricate fibrous polymer mats composed of fiber diameters ranging from several microns down to tens of nanometers. This study assesses the potential of electrospinning, as an alternative scaffold fabrication technique for tissue engineering applications. In this study, electrospinning is adapted to produce tissue-engineering scaffolds of two different size ranges composed of non-woven poly-L-lactide (PLLA) nanofibers and as a first study, the potential use of these scaffolds as tissue engineering scaffolds was …

Particle Size Dependence On Immobilized Molecular Sensors : Assay Of Nucleic Acid Probes Attached To Paramagnetic Particles, Celin Sunny

Theses

Nanotechnology is concerned with materials and systems whose structure and components exhibit novel and significantly improved physical, chemical and biological properties, phenomena and processes due to their nano scale size.

The transition from micro scale to nano scale leads to a number of changes in physical properties, possibly including new physical principles, some of which may be yet to be discovered. One of the major factors in this is the increase in ratio of surface area to volume.

This thesis research uses the increase in ratio of surface area to volume property of going from macro to micro to nano …

Biomimetic Sensor For In-Vivo Applications, Daya I. Sooryadas

Theses

The development of sensitive specific devices (e.g., molecular sensors) for the detection, diagnosis and monitoring of diseases, drug discovery, environmental detection of pollutants and/or biological agents has been an active area of research. A molecular sensor is a biomolecule or biomimetic molecule that performs two distinct functions in detecting target molecules. The sensor molecule recognizes a target molecule and specifically binds to it. This specific binding generates a signal in response to the event of target binding that can be then detected. The long term vision of this thesis research work is to develop a specific recognition ligand for detecting …

A Kinematic Analysis Of Hand Configurations In Static And Dynamic Fingerspelling, Gillian B. Sherry

Theses

The focus of this study was the investigation of target handshapes in American Sign Language fingerspelling in order to determine whether there was a difference between static canonical structures and structures produced in the context of a movement sequence. This was achieved by measuring the joint angles of a signing hand with an 18-sensor CyberGlove® by Virtual Technologies, Inc.

A discriminant analysis was used to identify targets that occurred at points of minimum angular joint velocity. A multivariate analysis of variance with planned compansons was then applied to these dynamic data along with the static data to test the hypothesis. …

Characterization Of Electrospun Dlplga Nanofibers For A Drug Delivery System For Intracranial Tumors And Avms, Kimberly A. Griswold

Theses

Electrospinning processes apply electric fields to a polymer solution in order to produce strands of polymer in the nanoscale range. These polymer fibers are manipulated for their porosity, high surface area, fineness and uniformity. In order to create the ideal drug delivery system for intracranial arteriovenous malformations (AVMs) and tumors, D, L poly-(lactice-poly-glycolide) (DLPLGA) nanofibers were electrospun in a tetrahydrofuran (THF) solvent. Three different concentration ratios of DLPLGA, 85/15, 80/20, and 75/25 were analyzed to obtain the prime base for drug annexation. 1 ,3-bis (2-chloroethyl)- 1 -nitrosourea (BCNU) was then codissolved with the DLPLGA nanofibers to form a homogenous solution, …

Design And Implementation Of Heart Rate Variability Measures In The Time Domain, Binoy John Mathews

Theses

The following study was conducted to design and implement computer programs to derive five time domain and two frequency domain Heart Rate Variability (HRV) measures from 24 hour Holter monitor recordings and to generate activity plots that display the variation of three of the five time domain measures and two frequency domain measures over a period of 24 hours.

Working with known pre and post experimental ECG data taken from a cyclical exercise program, standard parameters in both the time and frequency domains were derived using programs designed in Labview 7.0 engineering software package. Five parameters in the time domain …

Extending The Boundary Method For Solving Human Motion Problems Using A 3 Dimensional Coupled Pendulum Model, Avani Janardan Patel

Theses

Mathematical modeling, an evolving area in movement analysis research, couples quantitative measures of human motion with theoretical concepts in physiology and mechanics. Literature reveals two methods to solve for human motion problems, Forward and Inverse Mechanics. In this investigation, a new approach called the Boundaty Method is adopted to solve for human motion. This approach has the advantage of being able to solve for both new motions and the net muscular joint forces required to produce those motions but only at those discrete times and body configurations that are believed to be most crucial for accomplishing the task.

The method …

Extrusion And Evaluation Of Degradation Rate And Porosity Of Small Diameter Collagen Tubes, Bipinkumar G. Patel

Theses

The limited availability of autografts and failure of small diameter synthetic vascular grafts has stimulated continuing efforts to develop small diameter vascular grafts based on natural materials. The small diameter collagen tubes were extruded using bovine collagen type I. The biodegradation rate was determined and compared for small diameter collagen tubes crosslinked with glutaraldehyde and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and Nhydroxysuccinimide (NHS) to evaluate physio-chemical properties. The samples were also evaluated for their surface area and porosity using mercury porosimeter. The noncrosslinked tubes almost completely degraded after 2 hours. The tubes crosslinked with EDC/NHS degraded slower than the ones crosslinked with …

Measurement Of The Effectiveness Of Enhanced External Counterpulsation On Heart Rate Variability For Patients With Myocardial Ischemia, Kripa Jayaraman

Theses

This thesis is a study to measure the changes in heart rate variability due to the activity of the autonomic nervous system caused by the Enhanced External Counterpulsation treatment. The treatment is a non surgical, mechanical procedure that can reduce the symptoms of angina or Congestive Heart Failure, presumably by stimulating the opening, or formation of, small branches of blood vessels (collaterals) to create a natural bypass around narrowed or blocked arteries. It has been proved that rhythms can be markers of normal functional states. Even in the absence of external perturbations, the normal heartbeat is not characterized by clockwise …

Effects Of Sleep Deprivation On Autonomic Nervous System, Jaeyeaon Cho

Theses

Sleep deprivation (SD) has been thought a potential factor to trigger cardiovascular events by increasing the sympathetic nervous system activity. The aim of the present study was to evaluate the relationship between sleep deprivation and the autonomic nervous system activity by means of heart rate variability (HRV) and blood pressure variability (BPV). All data were acquired in the sleep lab of Columbia University.

Data were acquired from the two groups, SD and control. Subjects in the SD group did not sleep for thirty-six hours but subjects in the control group slept at night as usual. There were five different data …

An In Vitro Evaluation Of Tyrosine Derived Polyarylates And Polycarbonate As Polymeric Scaffold For Human Mesenchymal Stem Cells Osteogenic Differentiation, Manish Suresh Godbole

Theses

Human mesenchymal stem cells (hMSCs) obtained from the adult bone marrow are multipotential cells that are capable of differentiating along several lineages. They are readily available and abundant source of cells in the field of tissue engineering. For their use in treating certain connective tissue defect or disorders, their success depends at minimum on the use of scaffolds that support differentiation. Therefore , this thesis details a study that systematically evaluated hMSC differentiation on materials that exhibit gradual range in surface properties as a first study for selecting materials as potential scaffolds. Polycarbonates and polyarylates have combinatorial libraries that exhibit …

Voice Onset Time Variation In Stop Consonant To Vowel Transitions, Abhishek Gunvant Parikh

Theses

Reduced duration, increased consistency, and improved intelligibility are goals of reducing the motor complexity of speech for individuals with cerebral palsy having dysarthria. In this study, measurement and analysis were made to compare an individual with spastic Cerebral Palsy (CP) having dysarthria to an individual with athetoid CP having dysarthria as well as to a non-dysarthric individual. Each participant's normal speech, whispering, and speech using an artificial larynx was evaluated, utilizing the source-filter theory methodology. The plausibility of dysarthric speech duration reduction by minimizing vocalization is tested by stop consonant "P,, to vowel transitions. The data suggest that speech duration …

Spinning Of Collagen Fibers And Characterizing Thermal, Mechanical, Tensile And Structural Properties, Grace Evangelin Tatagiri

Theses

Collagen is the most important building block in the entire animal world. It plays an important role in regeneration of broken bones and wound healing, also helps grow blood vessels to feed the healing areas. The use of synthetic materials has been extensive, but these materials have there own limits and drawbacks. Poor biocompatibility of these materials is the main issue and often result in inflammations. Hence collagen is being heralded as one of the most appropriate replacement as an implantable material. The reasons being that it is a naturally occurring material, exhibits high biocompatibility low antigenicity and host response. …

A Labview Program To Obtain The Initiating Component Of A Vergence Eye Movement In An Open-Loop Experiment, Anuj P. Daftari

Theses

The vergence oculomotor system is used in viewing objects moving in depth, such as when a baseball player tracks a ball moving towards him. It is composed of two components according to the Dual Mode Theory; a fast preprogrammed initiating component and a slow feedback-controlled sustaining component. The initiating component is described with open-loop control and the sustaining component is described as a closed-loop feedback control system. Previously, several languages have been utilized to develop programs to study and isolate the open-loop portion of vergence eye movements. Presenting a subject with a stimulus, which initiates an open-loop response has been …

Development Of Fmri Compatible Lower Body Negative Pressure System, Pratap Singh Kunwar

Theses

The lower body negative pressure (LBNP) system provides a controlled, measured orthostatic stress to the cardiovascular system, which can be used with a magnetic resonance imaging (MRI) machine to study cardiovascular and cerebrovascular responses to graded LBNP. In the past, even though functional MRI (fMRI) was considered as one of the best modalities with which to measure small metabolic changes in the brain, it has not been used with an LBNP system to measure cerebrovascular changes. This was due to the lack of an fMRI compatible LBNP system.

In this project, an tMRI compatible LBNP system was first constructed without …

Investigation Of Heart Rate Variability During Sleep Apnea, Sekar Subramanian

Theses

Sleep apnea is a disorder, where there are repetitive pauses in respiratory flow of at least 10 seconds or longer duration, and which occur more than five times per hour. Apnea has strong modulating effects on the autonomic nervous system, with prominent heart rate variation. It can be assumed that during sleep, internal influences (sympathetic and parasympathetic nervous system activities) dominate the autonomic nervous system; in addition repetitive apneas are accompanied by a pronounced increase in average heart rate. The aim of this study was to investigate the heart rate variability using spectral analysis and time-frequency analysis during sleep apnea. …

Wavelet Transform Methods For Identifying Onset Of Semg Activity, Janina Wilen

Theses

Quantifying improvements in motor control is predicated on the accurate identification of the onset of surface electromyograpic (sEMG) activity. Applying methods from wavelet theory developed in the past decade to digitized signals, a robust algorithm has been designed for use with sEMG collected during reaching tasks executed with the less-affected arm of stroke patients. The method applied both Discretized Continuous Wavelet Transforms (CWT) and Discrete Wavelet Transforms (DWT) for event detection and no-lag filtering, respectively. Input parameters were extracted from the assessed signals.

The onset times found in the sEMG signals using the wavelet method were compared with physiological instants …

Transmission Of Light And Audible Sound In A Synthetic Fog Medium, Bhavin Babaria

Theses

The primary goal of the thesis was to study the propagation of visible light and auditory sound through a synthetic fog medium compared to an ambient air environment. It is known that the fog substantially decreases the visibility however; this has not been studied quantitatively. Further information regarding other energies such as sound is also needed to understand how the energy reacts in the fog medium. The extent of visual and auditory degradation in humans needs to be investigated. Researchers have studied light transmitted through water, air; however, no one has studied how light or sound is transmitted through a …

Evaluation Of Postural Stability Using Sensory Organization Test, Tiffany Sims

Theses

Poor postural stability of the elderly and other patients has been a major concern.The cost of treating injuries due to poor stability is expected to rise to $32.4 Billion by 2020. Many interventions have been proposed and used to improve stability. In order to determine the efficacy of these interventions, an objective evaluation of postural stability before and after intervention is important.

The aim of this thesis was to scientifically analyze the ambiguities in the equilibrium score (ES) given by the Neurocom Smart Equitest (NSE) machine, and compare it to a new measure of stability that has been proposed by …