Engineering Commons^™

Design And Fabrication Of A Microneedle For The Implantation Of Floating Microstimulators, Faysal Ahmed

Theses

Neural prosthetics are used to stimulate any remaining functional nervous tissue in order to restore function in visual, auditory, or other physiological components associated with the nervous system. Microelectrodes have been used in stimulating and detecting electrical activity in neurons. When stimulating or recording neural tissue activity using microelectrodes, there are usually many problems and difficulties in obtaining the correct functionality and results. There is great difficulty in placing these microelectrodes in a specific location in the central nervous system due to various problems with the methodology used. Many different techniques such as the traditional interconnected microelectrodes have been an …

Dem Simulated Radial And Axial Pressure In A Cylindrical Granular Column, Meng Cui

Theses

The study of packed beds of granular spheres and their applications are of great interest to industries, and one of the most important subjects that has been studied is cylindrical beds. In 1895, H. A. Janssen discovered that in a vertical cylinder the pressure measured at the bottom does not depend upon the height of the filling in contrast to Newtonian fluids that possess linear hydrostatic pressure equilibrium. One of assumptions of his theory stated that the horizontal pressure is proportional to the vertical. In this thesis, this physical hypothesis is investigated using Discrete Element Simulations of inelastic with a …

Density Relaxation Of Granular Matter Through Monte Carlo And Granular Dynamics Simulations, Oleksandr M. Dybenko

Dissertations

Granular materials are the principal ingredients of the industrial complex involved with the handling and processing of bulk solids including pharmaceuticals, chemicals, agricultural and mining materials. Despite the enormous importance of these materials in society, their behavior is not well-understood; in fact, there is no known model available that is capable of predicting the wide range of phenomenon that have been observed. One of the most important of these is known as density relaxation. Here, a granular material undergoes an increase in solids fraction as a result of the application of discrete taps or continuous vibrations.

In this dissertation, the …

Production Of Nanocrystalline Rdx By Ress : Development And Material Characterization, Victor Stepanov

Dissertations

The aim of the present work was to address the hazardous vulnerability of energetic materials to accidental initiation. An improved form of the explosive RDX with a significantly reduced sensitivity to stimuli including shock and impact was sought. The direction of this research was to investigate the effect of RDX crystal size reduction down to nano-scale dimensions on the sensitivity characteristics. Although size reduction of energetic crystals has been demonstrated often to result in a sensitivity reduction, the effect at the nano-scale particle size has not been investigated.

To generate nanocrystalline RDX a recrystallization process was developed based on rapid …

Optimal Allocation Of Blood Products, Godson A. Tetteh

Dissertations

The high cost of collection and the short shelf life of apheresis platelets demand efficient inventory management to reduce outdates and shortages. Apheresis platelets are licensed for seven days, and blood centers are keen on knowing the consequences of various product collection and distribution strategies. To reduce outdates, inventory managers typically distribute the older units first, thereby following first-in first-out (FIFO) policy; however, hospital blood banks would prefer that the blood center issues out the freshest units first, equivalent to a last-in first-out (LIFO) policy. This study addresses the optimal distribution policy to achieve a desired outdate, shortage and average …

Optical Properties And Carrier Transport In Si/ Si1-Xgex Nanostructures, Eun Kyu Lee

Dissertations

Defect-free epitaxial growth of Ge on a ~4 % lattice-mismatched single-crystal Si substrate is achieved using reduced dimension nanoscale heterostructures, where efficient structural relaxation might occur due to an enhanced adatom migrations and high surface-to-volume ratio. For development of novel electronic or optical devices based on these novel structures, understanding of their electrical and optical properties is crucial. This study explores the optical properties and carrier transport in two different types of Si/Si _1-xGe _xnanostructures: Ge nanowires (NWs) forming nanoscale heterojunctions with Si substrates and multilayers of SiGe clusters embedded into a Si matrix.

Micron-long Ge nanowires grown …

Micro, Meso And Macro Materials Processing Using High-Speed Liquid Projectiles, Veljko Samardzic

Dissertations

The objective of this research is developmentof aknowledge base of materials processing by the impact of high-speed liquid projectiles. The work involved experimental study of generation and applications of high-speed liquid projectiles. The projectiles were generated by the launchers, which used gunpowder as an energy source. The experiments were carried out at the low (O.35g of the powder), middle (1.2g) and high (10g to 70g) levels of energy consumptions and at several different launchers modification.

Experimental investigation of effect of gun powder mass on energy of projectile was conducted for ductile and brittle targets. An array of experimental …

Removal And Recovery Of Fermentation-Produced Volatile Organic Compounds By A Novel Liquid Membrane-Based Pervaporation Technique, Atsawin Thongsukmak

Dissertations

Pervaporation is an energy -- efficient alternative to distillation for removing volatile organic compounds (VOCs) from water especially solvents from their dilute solutions in a fermentation broth. Liquid membranes have high selectivities for removing solvents from aqueous solutions compared with polymeric membranes or ceramic membranes; however liquid membranes have stability problems due to various losses. The loss of liquid membrane (LM) to the feed solution leads to toxicity for the organisms in a fermentation broth. A new liquid membrane based pervaporation technique has been developed to achieve high selectivity, ensure stability and prevent contamination of the fermentation broth. Trioctylamine (TOA) …

Modeling Inventory And Responsiveness Costs In A Supply Chain, Robert Nearier

Dissertations

Evaluation of supply chain performance is often complicated by the various interrelationships that exist within the network of suppliers. Currently many supply chain metrics cannot be analytically determined. Instead, metrics are derived from monitoring historical data, which is commonly referred to as Supply Chain Analytics. With these analytics it is possible to answer questions such as: What is the inventory cost distribution across the chain? What is the actual inventory turnover ratio? What is the cost of demand changes to individual suppliers? However, this approach requires a significant amount of historical data which must be continuously extracted from the associated …

Vector Support For Multicore Processors With Major Emphasis On Configurable Multiprocessors, Hongyan Yang

Dissertations

It recently became increasingly difficult to build higher speed uniprocessor chips because of performance degradation and high power consumption. The quadratically increasing circuit complexity forbade the exploration of more instruction-level parallelism (JLP). To continue raising the performance, processor designers then focused on thread-level parallelism (TLP) to realize a new architecture design paradigm. Multicore processor design is the result of this trend. It has proven quite capable in performance increase and provides new opportunities in power management and system scalability. But current multicore processors do not provide powerful vector architecture support which could yield significant speedups for array operations while maintaining …

Synthesis Of Corn-Derived Carbohydrate Derivatives As Effective Multifunctional Sunscreen, Xianhong Feng

Theses

The eighty-years-old sunscreen industry is sustained by the growing incidence of skin cancer and the continual exploration of skin aging. From the UVB-induced erythema to the UVA-induced persistent pigment darkening, scientists have used versatile methods to reveal that not only does UVB damage skin but also that longer wavelengths such as UVAIL (290nm ~ 340nm) and UVAL rays (340nm ~ 400nm) trigger skin cancer, premature skin aging and immunosuppression.

To meet a significant demand for improved photoprotection, a broad-spectrum sunscreen with a high extinction coefficient has been desired. As part of our ongoing studies on isosorbide-cinnamate derivatives, this work have …

Derivation Of The Respiratory Rate Signal From A Single Lead Ecg, Murtaza M. Lakdawala

Theses

It has been long established that respiration has an influence on heart rate, and this effect is called respiratory sinus arrhythmia. As a result, two inferences can be postulated: first respiration information can be derived from cardiac activity, and second this effect offers the potential of removing the respiration effect that suppresses cardiac information which is of clinical significance. As a result of research performed at NJIT, there is a significant amount of data on exercise and heart rate recovery, but not the associated respiration signal. The motivation of this research was to compare and implement an optimal ECG derived …

Thermal And Morphological Analysis Of Collagen-Plla Electrospun Blends, Angana Banerjee

Theses

Electrospinning of bovine Type I collagen and Poly (L-lactic acid) produces blended nanofiber scaffolds that may have application in tissue engineering, wound dressing and drug delivery.

The goal of this research work was to produce and characterize blended nanofibers of a protein, collagen, and a synthetic polymer, poly (L-lactic acid). This study focuses on the in-depth analysis of the appearance of the structural relaxation occurring at the glass transition temperature of PLLA in the collagen-PLLA blended electrospun mats. It is speculated that occurrence of this thermal event is more prominent in PLLA with high molecular weight due to the presence …

Altered Brain Activity In Autistic Children Versus Healthy Controls While Performing Simple Tasks Using Fmri, Donald Martin Adams Jr.

Theses

Functional magnetic resonance imaging (fMRI) studies dealing with Autistic children have primarily been concerned with cognitive facial recognition. Recent studies have demonstrated that Autistic children, when compared to healthy matched controls, exhibit higher neuronal activity when identifying patterns or objects, but lower levels of activity in regards to facial recognition.

The objective of this study was to examine both facial and object recognition and compare them to simple sensorimotor tasks. All subjects were administered 5 stimuli each lasting 320 seconds. Subjects were instructed to use a button press box to identify between a Person/Object and an Arrow/Object. They were then …

Automated Multi-Well Neural Injury Device, Linda Y. Chen

Theses

Traumatic Brain Injury (TBI) is a wide spread pathological problem occurring in 1.4 million individuals every year according to the National Institute of Neurological Disorders and Stroke. There are several types of TBI and the most prominent ones are concussion, contusion, hematoma, coup-contrecoup injury and diffuse axonal injury (DAI). The most severe type and the one that is the hardest to diagnose is DAI. DAI occurs mostly due to accidents relating to automobile, motorcycles and in some cases fall and assault, resulting in a "shearing" phenomenon of the brain. Patients with DAI can range from being, mildly injured, severely disabled …

Raman Scattering In Free Standing Porous Si Films, Thenappan Chidambaram

Theses

In this thesis, Raman Scattering of free standing porous silicon on sapphire samples of controllably varying porosity is studied. The free standing, fully crystalline porous silicon films were prepared by electrochemical etching and the porous structure were lifted-off by a procedure based on electro-polishing. During Raman scattering measurements, the samples are exposed to relatively high intensity laser radiation. Free-standing porous Si sample temperature and thermal conductivity are calculated by comparing intensities of Stokes and anti-Stokes Raman peaks. Compared to crystalline Si, we find strong decrease in thermal conductivity accompanied by a change in the phonon spectra. Also, comparing Stokes and …

Surface Recordings Of Evoked Field Potentials From The Cerebellum With A Flexmea Microelectrode Array, Jonathan David Groth

Theses

The cerebellum is an integral part of multijoint control. There are two input pathways to the cerebellar cortex, the mossy fiber and the climbing fiber pathways. The mossy fiber pathway forms a disynaptic input to Purkinje cells through the granular cells. This disynaptic input produces a multicomponent field potential composed of the P1, N 1, N2, N3, N4, and P3 waves. The climbing fiber input forms a monosynaptic input to the Purkinje cells and thus creates a much simpler field potential.

The mossy and climbing fiber field potentials were recorded with a FlexMEA microelectrode array from the pial surface of …

Experimental Investigation Of The Fluid Velocity Distribution In Stirred Tank Reactors Equipped With Retreat-Blade Impellers Using Laser Doppler Velocimetry, Deepak Rajesh Madhrani

Theses

Stirred tank reactors are commonly used in the pharmaceutical industry for synthesis of Active Pharmaceutical Ingredients (API's) and their intermediates. Typically, these vessels are glass-lined and are provided with a single retreat-blade glass-lined impeller and a single baffle. Despite their ubiquitous utilization in the pharmaceutical industry for at least the past 40 years, the mixing characteristics of these systems have not been studied to any great extent, making it difficult to predict mixing performance in any given operation.

In this work, the velocity distribution inside the typical glass-lined vessel/impeller system was experimentally quantified using Laser Doppler Velocimetry (LDV), which is …

Synthesis And Analysis Of Carbon Nanowalls And Their Raman Spectroscopy, Amit Mahajan

Theses

Growth of Carbon Nanowalls has been carried out by Radio Frequency Chemical Vapor Deposition (RF-PECVD) on various substrates. Hydrogen was used as an active gas for the growth where as Ethanol bubbled with Argon was used as carbon source for formation of Carbon Nanowalls (CNW). The growth was then confinned by Raman Spectroscopy and Scanning Electron Microscope (SEM) images. Also the need of using catalyst in CNW has been analyzed. The intensities of D and G bands obtained from Raman spectrum have been related to the length of Graphene walls, to study the CNW's length on different substrates.

The growth …

Interactions Between Adult Human Mesenchymal Stem Cells And Nanofibrous Scaffolds Of Different Compositions, Lisamarie Moore

Theses

Stem cells have become increasingly important in the biomedical field because they have the potential to invade and regenerate damaged tissue. In particular, the bone marrow contains meesenchymal stem cells (MSCs) that have the capacity to differentiate into many cell lineages. The incorporation of MSCs within a multidimensional biomaterial provides a delivery vehicle to areas of injury. Natural and synthetic biomaterials can be made into scaffolds to represent different types of tissues. The ratio of synthetic to natural biomaterials in the scaffold influences the interaction with MSCs. This thesis created two different nanofibrous scaffolds by a process of electrospinning. The …

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 …

Multiclass Intermodal Network Model : The Use Of Combined Model On System Evaluations, Yi Deng

Dissertations

United States transportation policy has generally addressed the negative economic and social effects of the standpoint of individual transportation modes and local government involvement. Therefore, there has been an increased focus on the development of intermodal transportation. Integrating the modes and using each of them to its best advantage are strategies to optimize the existing resources and to create new capabilities.

According to the literature review performed in this research, the research in intermodal transportation system evaluation is far from mature. Most transportation performance measurements are focused on one mode rather than a whole network. In practice, the data necessary …

Design And Analysis Of Scalable Scheduling Schemes For High-Speed Input-Queued Packet Switches, Chuan-Bi Lin

Dissertations

Single-stage input-queued (IQ) switches are attractive for implementation of high performance routers because they require no speedup in the used memory. It has been shown that IQ switches can provide 100% throughput under admissible traffic when using either maximum-weight matching schemes or iterative maximal-weight matching schemes with a significant speedup. These different approaches require either high computation complexity or high memory costs that can make them infeasible. Therefore, there is a need for low-complexity and fast matching schemes that provide high throughput under several admissible traffic patterns, without recurring to speedup nor multiple iterations. In this thesis. the concept of …

Architecture Design And Performance Analysis Of Practical Buffered-Crossbar Packet Switches, Ziqian Dong

Dissertations

Combined input crosspoint buffered (CICB) packet switches were introduced to relax inputoutput arbitration timing and provide high throughput under admissible traffic. However, the amount of memory required in the crossbar of an N x N switch is N²x k x L, where k is the crosspoint buffer size and needs to be of size RTT in cells, L is the packet size. RTT is the round-trip time which is defined by the distance between line cards and switch fabric. When the switch size is large or RTT is not negligible, the memory amount required makes the implementation …

Propagation And Scattering Of Beam Waves In Vegetation Using Scalar Transport Theory, Michael Yu-Chi Wu

Dissertations

Vegetation is a very complex propagation medium, and multiple scattering effects play a significant role in the propagation of microwave and millimeter (mm)-wave signals through foliage. At frequencies above 1 GHz,both the coherent and incoherent field components have to be taken into account and vegetation has to be modeled as a random medium of discrete scatterers having a wide variety of sizes and shapes. Multiscattering can be studied effectively by using transport theory. In prior studies, theories have been developed for microwave and mm-wave propagation in vegetation using transport theory for continuous wave and pulsed signals. In this study, the …

Optimized Scheduling Of Highway Work Zones, Yimin Tang

Dissertations

Highway maintenance activities usually require lane closures and disrupt traffic operations. Because of budget constraints, project deadlines, and the resulting traffic impact, the objective of this dissertation is to improve the efficiencies of traffic operation and maintenance work, and minimize the total project cost (i.e., agency cost and road user cost) by optimizing work zone schedules.

This dissertation focuses on the maintenance projects on multiple-lane highways. The objective total cost function is formulated while considering a discrete maintenance time-cost function and time-dependent traffic diversions. However, the work zone scheduling problem is a combinatorial optimization problem and difficult to solve analytically. …