Engineering Commons^™

A Comparative Study Of Common Crosslinking Agents For Electrospun Collagen Scaffolds, Pallavi Masih

Theses

Cartilage injury is one of the leading causes of knee pain in the world. Over two million Americans suffer from cartilage injury every year, resulting in swelling, pain or joint impairment, causing it difficult to maintain an active life style. Synthetic grafts are used extensively to restore tissue functions. The major drawback limiting successful incorporation of synthetic grafts in body is their lower ability to integrate to natural tissue, poor biocompatibility which often results in triggering immunogenic responses, causing graft rejection. Collagen is thus studied and used excessively as a successful implantable material. The reason being that it is natural …

Process-Structure-Property Relationships Of Resorbable Desamino Tyrosine Derived Polymers : Effect Of Backbone Chemistry And Assembly On Drug Delivery, Pinar Nebol

Theses

The selection the correct biomaterial for a specific medical application plays an important role for the success of both application and the device. Since different applications require different properties, investigation and improvement of biomaterials with different properties are very important. L-tyrosine derived polymers enable the manipulation of the properties of the material by changing backbone or pendent chain structure. L-tyrosine derived polyarylate is one of the class of these materials.

This study investigates the behavior of the tyrosine derived polyarylates under in vitro conditions. The change of structure caused by incubation in phosphate buffer solution and the effect on the …

Design And Construction Of A Novel Transpalpebral Ophthalmic Tonometer, Philippe R. Moinot

Theses

Glaucoma -- a degeneration of the optic nerve- is a leading cause of blindness which is primarily caused by large fluctuations in intraocular pressure (lOP) known as diurnal variations. Because these peak in the early morning dropping off rapidly, a self administrable and inexpensive lOP home testing procedure is highly desirable. The approach contained herein -- unlike traditional Goldman applanation tonometry which requires the use of ophthalmic anesthetics and complex diagnostic equipment- describes a novel lOP measurement method consisting of concavation of the cornea or sclera through the palpebra superior by the spherical tip of an optoelectronic photodetector suspended in …

A Virtual Training Environment For Wheelchair Mounted Robot, Elizabeth Leichtnam

Theses

A model of a robotic manipulator designed to respond to different inputs from users with different skills or conditions is presented. This model can be adapted to different input variables and converted into joint angles which relate to movement in space of the manipulator's links. The algorithm allows for real time response and the features of the virtual environments (i.e., 3D design, stereoscopic vision) gives the designers the opportunity to use this model for training and usability evaluation according to the skills and different conditions that users could present.

Two types of virtual environments were created aiming to be used …

The Synergistic Effect Of Pulsed Electromagnetic Fields And Demineralized Bone Matrix On The Osteogenic Differentiation Of Mesenchymal Stem Cells, John Manocchio

Theses

Orthopaedic bone grafting continues to be a mainstay in the treatment of non unions and other difficult to heal bone defects. Tissue engineering strategies have focused on providing bone graft materials that are osteoconductive, osteoinductive and osteogenic in order to achieve optimal bone healing. Furthermore, electrical stimulation technologies such as pulsed electromagnetic fields (PEMF) have been used to enhance the effectiveness of bone graft materials. PEMP has been shown to have a synergistic effect with BMP-2 and it was hypothesized that PEMF would have the same effect with demineralized bone matrix (DBM). In the present study human mesenchymal stem cells …

Effects Of Natural And Accelerated Weathering On The Performance Of Locally Manufactured Polymer-Modified Bituminous Waterproofing Membranes, Rauda Ali Saeed Al Saadi

Theses

As in most industrial sectors, today there is a growing preoccupation about product quality. Since waterproofing systems are intended to have the longest possible service life, one of the most critical quality features is their aging performance. As a result, the importance of aging tests is steadily growing, especially in the hot-dry climate zones.

Polymer-modified bituminous waterproofing membranes are normally exposed to solar radiation and various weathering conditions when used in residential and commercial buildings. They are attacked and deteriorated to some degree by environmental factors such as heat, radiation, especially ultraviolet, moisture and gases. The weathering (aging) consequences commonly …

Cortical Location Of Saccadic And Vergence Oculomotor Learning Using Fmri, Yelda Alkan

Theses

Motor learning is critical to the survival of a species and changes throughout life via neuroplasticity. The brain receives most of its information about the external world via the visual system. Eye movements are used to direct the visual information of interest to the fovea, the area of the retina which has the highest density of photoreceptors, and the largest amount of cortical area. This research will study how two of the five eye movement systems utilize oculomotor learning. Saccadic eye movements are used to quickly shift the fovea to objects using conjugate movements typically used during reading. The vergence …

The Use Of Instrumented Measures To Describe Lower Extremity Joint Mechanics, Steven Thomas Kaufman

Theses

Currently, various biomechanical assessments are used in clinical settings that offer diagnostic information about the studied joint. These assessments, however, are based on the judgment and experience of the therapist conducting the test and have a high degree of inter and intra rater variability, decreasing the strength of the observation. A set of instrumented measures consisting of a force/torque sensor and an angle sensor was created to quantitatively assess the mechanics of the lower extremity joints as a possible solution to the low repeatability of commonly used clinical tests.

It was shown through the use of instrumentation that the torques …

Dexamethasone- And Age-Sensitive Genes In Neonatal Small Intestine, Carla Cerqueira

Theses

Regulation of GLUT5 is dependent on the presence of its substrate, fructose, but it is also correlated with the developmental (aging) process of the intestine. To identify fructose-responsive genes whose expression also changes with age, intestines of 10 and 20 d old pups were perfused, by Ferraris et al., with fructose and then compared by microarray analysis. From this, a gene clustering analysis revealed that some age- and fructose-specific genes are regulated by corticosterones, which normally increase in pups ≥ 14 d old. Subsequent work indicated that priming the gut with Dexamethasone (Dex, a glucocorticoid analog) allowed fructose to precociously …

Penetration Force Measurements In The Central Nervous System With Silicon Electrodes, Ashwini Arun Nikam

Theses

One of the major challenges in neural engineering is the tissue damage that occurs during insertion of microelectrodes into the central nervous system. The damage occurs as a result of the dimpling effect that is due to the insertion force. A method which can reduce the penetration force can also reduce dimpling and the resulting tissue damage.

There are two objectives in this thesis. One is to measure the penetration force with Michigan electrodes, which are silicon based electrodes. The second is to reduce the penetration force by using mechanical vibrations.

First, the penetration force was measured in the rat …

Two Factor Authentication And Authorization In Ubiquitous Mobile Computing, Qing Zhu

Theses

Handheld devices, such as mobile phones, PDAs and others, have become an integrated part of our lives. They are perfectly suitable to become the first real-life platforms for mobile computing applications. A lightweight holistic authentication and authorization scheme is presented for this typical wireless scenario. It is shown that either SIM or Kerberos authentication has its limitations. A two-factor authentication method SIM-based Kerberos authentication is developed to implement the Secure Single Sign-on function with LDAP protocol realization for authorization and mobile directory services. Performance analysis and power consumption analyses for this protocol are presented as well. Our results show that …

Mixing Of Nanoparticles In A Stirred Tank In High Pressure Carbon Dioxide, Nitin Aggarwal

Theses

Mixing of nanoparticles of different compositions offers wide opportunities in manufacturing new nanocomposite materials with unique electronic, optical, mechanical, and chemical properties. However, due to large cohesive forces between nanoparticles, they often form large micron-sized agglomerates, thus losing their main advantage of small size and high surface area. Therefore, breaking of these agglomerates is necessary prior to mixing. One of the techniques to achieve deagglomeration and mixing of nanoparticles is based on rapid depressurization/expansion of supercritical suspensions. where the suspension of initially premixed agglomerates in supercritical CO₂ pass through the nozzle undergoing deagglomeration as a result of rapid expansion …

Kerberos Phone Secure Messenger, Nabeel Al-Saber

Theses

Security is becoming vital in today's open insecure Internet. While popular Internet enabled mobile devices are spreading widely, the security of such platforms is not maturely addressed. This research extends the popular Kerberos authentication protocol to run on mobile phones and builds a novel Kerberos Secure Phone Messenger (KSPM) on top of the protocol. Moreover, the Kerberos network authentication protocol provides user authentication and message privacy with the convenience of secret key cryptography. Such an advantage in mobile phones helps reduce the computational burden and power consumption if compared with public key cryptography. KSPM achieves high standards in terms of …

Ignition Of Metal Powder By Electrostatic Discharge Stimulation, Ervin Beloni

Theses

Energetic formulations with metal fuel additives are extensively used in propellants, explosives, pyrotechnics, and incendiaries. Currently, replacement of regular metal powders with nanocomposite metal-based materials is being considered. Such nanocomposite reactive materials are capable of very high reaction rates while maintaining the high combustion enthalpies characteristic of metals. However, such novel reactive nano-materials are often highly sensitive to impact, friction, and electrostatic discharge, making them difficult to handle. In particular, their high electrostatic discharge sensitivity (ESD) was reported. While ESD testing is very common and standardized, the mechanisms of powder ignition by electric spark remain unclear. This project is aimed …

Design Of Three-Dimensional Axon Stretch Growth Device, Fayekah Assanah

Theses

Spinal Cord Injury (SCI) causes destruction and degeneration of axons in the white matter of the spinal cord, resulting in functional loss and paralysis. A successful treatment of SCI requires axons to regenerate across damaged regions. Current studies focus on identifying mechanisms to promote axon regeneration in lesions and have yet to be successful in preventing nerve degeneration due to scar tissue formation. Establishing axonal bridges over long distances of SCI lesions remains a challenge, resulting in poor functional recovery. Instead of relying on promoting axon regeneration into lesions, Pfister et al. has developed a transplantable nervous tissue construct spanned …

Pattern Recognition Of Brain Fmri Images For Various Physiological States, Priyanka Bhatt

Theses

The development of fMRI (functional Magnetic Resonance Imaging) has led many researchers to localize brain functions using different stimuli. The use of pattern recognition techniques have made it possible to predict the stimuli being presented from the corresponding brain images and activation patterns. The primary objective of the present study was to use pattern recognition methods to develop a model using available fMRJ images and then to use the model to identify the stimulus presented from a large number of unknown images. Two different experimental conditions were used involving both binary and multi-class classification. Bilateral finger tapping data which had …

Fracture Healing : The Effects Of Local Insulin Delivery Via Calcium Sulfate And Tricalcium Phosphate, Sarah Elizabeth Buchala

Theses

Previous studies have documented the major role played by insulin in osseous healing. This is the first study to examine local intramedullary insulin delivery to the fracture site and its effect upon the normal fracture healing process. Preceding results show that when administered at the fracture site of the impaired fracture healing model of the diabetic BB Wistar rat, insulin will regulate early cellular proliferation and chondrogenesis and late mineralized tissue, cartilage content and mechanical strength.

In this study, two novel delivery vehicles have been evaluated for sustained insulin release in the normal fracture model of the BB Wistar rat. …

Multi Well Uni-Axial Stretch Injury Device, Mridusmita Choudhury

Theses

Most diffuse brain injury is the result of uni-axial stretch of brain axons in traumatic brain injury. Traumatic injury to axons throughout the brain and is believed to be a major cause for coma, and other complications. Diffuse axonal injury is mostly multi-focal and appears throughout the deep cortical and sub-cortical regions.

Several models have tried to replicate this phenomenon. Previous models, like the Penn model, have lower throughput as they conduct experiments on one well at a time, and it has lower reproducibility as well. The other problem with these models is that they are not very user friendly, …

Creating New Visualization And Human Interface Devices For Theraputic Video Games, Kunal Jayant Doshi

Theses

Virtual reality (VR) gaming environment as a tool for rehabilitation of patients with upper extremity disorders is fast gaining momentum. VR based motor training systems provide an engaging, motivating and adaptable environment where the motion of the limb displayed in the virtual world is a replication of the motion produced in the real world by the patient's extremity.

The goal of this thesis was to create a generic gaming system which can be interfaced to a number of different Human interface devices (HID) and produce rich graphics to create a virtual environment which closely resembles the real world. This would …

Comparison Of Linear Parametric Models For Predicting Fmri Response, Parina Gandhi

Theses

In this study, five different linear parametric models including Autoregressive model (ARX), Autoregressive Moving Average Model (ARMAX), Box-Jenkins Model (BJ), Instrument Variable Model (IV) and Prediction Error Model (PEM) were used to predict the fMRI response and their performances compared. Transfer functions were computed for every voxel time series for every subject using all the parametric models. Cross-correlation was subsequently performed between the predicted response and the actual fMRI data to compare the performance of the five models. The consistency of the models and the transfer function was checked by doing a statistical analysis. Among the five models tested, PEM …

Brain Segmentation Using Endogenous Contrast Mechanism Using Breath Holding Fmri Signal For Tissue Characterization, Samata Mukesh Kakkad

Theses

MRL has fast become the modality of choice for the analysis of the complexity of the human brain. MRJ is a non-invasive method and gives high spatial resolution maps of the brain with soft tissue contrast. Conventional MRI technique modified to be used to image the functionality at high temporal resolution is known as fMRI. In fMRI the BOLD signal we measure is the hemodynamic response to neuronal and vascular changes at rest or in response to a stimulus where the various tissue types will have a different response.

While fMRI has been traditionally been used to detect and identify …

A Stereoscopic System Using Knowledge Propagation To Achieve Accurate Depth Calculation, Chaitali Mulay

Theses

With the advent of the twenty first century, stereoscopic systems have found a widespread use in the engineering industry. Several biomechanical analyses utilize this concept for efficient information extraction. Some examples of its applications are gait analysis, hand shape recognition, facial surface recognition etc.

The primary goal of this thesis was to optimize the existing stereoscopic system, to increase accuracy and precision of the depth information extracted. The process included redesign of the existing equipment set-up, automation of image acquisition unit and modification of conventionally used correspondence test to achieve higher accuracy. The acquired data was used to estimate depth …

Mapping Inter-Subject And Inter-Regional Brain Connectivity During Free Viewing Of Novel Natural Scenes, Sheela Nagaraj

Theses

Traditional functional magnetic resonance imaging (fMRI) studies have used controlled tasks such as finger tapping to isolate function in distinct cortical. Recent studies have examined the mechanisms involved during natural conditions by asking subjects to freely view the presentation of a movie. The objective of our study was to further observe the extent to which similarities are present between subjects during natural vision. It was hypothesized that there would be a linear relationship between the percentage of region-specific overlap, which is the percent of the anatomical region of interest which contains spatial activation exhibited by all six subjects, and corresponding …

Finger Joint Impedance Control Applications To Investigate Spasticity, David Naisby Paglia

Theses

In order to investigate how spasticity disrupts the capabilities of the human body, a better understanding of how joint impedance control operates in healthy individuals is necessary. In this investigation, a second order rotary torque model was implemented to investigate the impedances at the metacarpophalangeal (MCP) joint of the index finger. The model was fit to approximately 25 milliseconds of force and displacement data to determine the mechanical impedances at the finger tip. Ranges of damping and stiffness were optimized over a range of mean finger tip force (0-12 N) for extension. The equilibrium-point hypothesis was examined when compared to …

Design Of Gait Rehabilitation System, Andriy Pletenetskyy

Theses

This thesis describes the conceptual design of an innovative robotic rehabilitation machine whose purpose is to help in the recovery of people with motor function disabilities. The machine is smaller, simpler and cheaper than current solutions on the market yet it delivers same functionality.

The conceptual development of the gait rehabilitation system also features a human model with average anthropometric dimensions that allows better visualization and understanding of the actual machine operation. The human model is kinematically coupled to the machine and the whole assembly presents a complex mechanism that closely simulates gait training session.

Three-dimensional modeling and analysis techniques …

Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee

Theses

The problem of designing retransmission protocols based on Hybrid Automatic Repeat reQuest (HARQ) for moving networks over Ricean fading channels has been considered. The scenario of interest consists of one receiver traveling at a given speed while connected to a wireless network based on OFDM (e.g., WiMax) through several base stations located along the path. Five different retransmission protocols that combine HARQ with handover between adjacent base stations are considered. Their performance in terms of number of retransmissions per packet via numerical simulations, considering both frequency selective and nonselective channels are presented. The results obtained show the relevant advantage that …

Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin

Theses

With the continuous expansion of network infrastructure and deployment of applications sensitive to Quality-of-Service, network measurement plays a major role in both network planning and management. Accurate measurement of various network parameters, e.g., available bandwidth, link capacity, delay, packet loss and jitter, provides a positive impact for effective traffic engineering, Quality-of-Service (QoS) routing, optimization of end-to-end transport performance, and link capacity planning. For network measurement, there exists several proactive estimation tools based on either probe-gap model or probe-rate model that estimate path related attributes. Most of these tools that have been implemented can measure tight-link capacity (smallest available bandwidth) and/or …

Phase Transfer In A Collision Between A Droplet And Solid Spheres, Zheng Shen

Theses

The hydrodynamics of a liquid droplet impinging on a particle is of direct relevance to many engineering applications. The mechanism of heat and mass transfer during the droplet solid collision is essential to the design and operation of many industrial systems. However, very limited systemic research is available to describe the droplet impact on hot solid spheres.

This paper aims to establish a systematic investigation of phase transfer due to the droplet-solid impact, by both experimental and modeling approaches. The targeted phase transfer includes the surface attachment, mass of vaporization, heat transfer to droplet and its partition between vaporization and …

Ultra-Fine Particle Formation Using Principle Of Rapid Expansion Of Supercritical Solutions`, Miraj Minesh Sheth

Theses

There are indications in the chemical and pharmaceutical industries that the reduction in size of a crystalline particle can lead to better performance of the drug compound, particularly for water insoluble drugs, in the final dosage form. Many particle formation techniques have been investigated in recent years by researchers to obtain desired particulate sizes and size distributions. Supercritical fluid technologies have been successfully investigated for particle formation due to its unique gas/liquid properties in the supereritical state. In this report, results of particle formation using the principles of Rapid Expansion of Supercritical Solutions (RESS) have been documented.

In the RESS …

Fully Dense Aluminum-Rich Aluminum Copper Oxide Powders For Energetic Formulations, Demitrios Stamatis

Theses

The thermite reaction between Al and CuO is well known and highly exothermic. For a conventional thermite mixture comprising mixed metal and oxide powders, this reaction is rate limited by the slow heterogeneous mass transfer at the metal and oxide interface. The relatively low reaction rate and a difficult ignition have restricted practical applications for this reaction. For newly developed, nano-composed thermites, the interface area can be substantially increased resulting in a much higher reaction rate and a new range of possible applications. Nanocomposite Al-CuO materials are produced using a technique referred to as arrested reactive milling. Regular metal and …