Engineering Commons^™

Delay Line Based Passive Radio Frequency Identification Tags, Aravind Chamarti

Doctoral Dissertations

This work describes the concept, design, fabrication, and characterization of delay-based radio frequency identification (RFID) tags and RFID-based sensor tags, representing a novel RFID technology. The presented delay-based RFID concept is based on the LC-delay-line and transmission-delay-line based approaches. The proposed concept allows the realization of RFIDs and RFID-based sensor tags at any allowed radio frequency, with the limitation of realizing delay elements capable of producing required delays. The RFID configurations presented in this work are for operation at 915 MHz. Simulations are used to design and optimize components and devices that constitute the tags, and to integrate them to …

Multicomponent Patterning Of Nanocomposite Polymer And Nanoparticle Films Using Photolithography And Layer-By-Layer Self -Assembly, Javeed Shaikh Mohammed

Doctoral Dissertations

In this dissertation, the fabrication, characterization, and application examples of 3D multicomponent nanocomposite micropatterns (MNMs) with precise spatial arrangements are described. The ability to produce such small-scale 3D structures with versatility in composition and structure is a new development based on the integration of nanoscale layer-by-layer (LbL) self-assembly and microscale photolithographic patterning, enabling construction of surfaces with microscale patterns that possess nanotopographies. The techniques used here are analogous to surface micromachining, except that the deposition materials are polymers, biological materials, and colloidal nanoparticles used to produce 3D MNMs. A key feature of the resulting 3D MNMs is that the physical …

Development Of Self-Assembled Monolayer-Based Cell Culture Platform Towards Fabrication Of A Three-Dimensional Bioreactor, Rajendra Kandoor Aithal

Doctoral Dissertations

The extracellular matrix (ECM) plays an important role in regulating a number of cellular properties and functions like cell differentiation, cell synthesis and degradation, cell viability and proliferation, cell function, and cell aging. Surface modification of planar substrates with self-assembled monolayers (SAMs) is a promising technique to achieve stable ECMs.

In this work, substrates such as silicon (Si), gallium arsenide (GaAs) and indium tin oxide (ITO) substrates were modified with SAMS containing amino (-NH2), methyl (-CH3), thiol (-SH) and carboxylic (-COOH) end groups and characterized using contact angle measurements, surface infrared (IR) spectroscopy and atomic force microscopy (AFM). Different cell …

Development And Applications Of Inkjet Printed Conducting Polymer Micro-Rings, Rajneek K. Khillan

Doctoral Dissertations

A drying sessile drop moves the solute particles to the periphery where they get deposited in the form of a ring. This phenomenon is prevalent even with micro drops falling at high velocity from a piezo-actuator based inkjet printer. In polymer microelectronic field, this phenomenon is a major challenge for fabricating devices using inkjet printing. We exploited this problem and applied it for various novel applications in the field of polymer microelectronics.

Various dispensing techniques and temperature variations for micro-drop printing were used for modifying the micro-drops in such a way that the periphery of the micro-ring holds most of …

Designing And Modeling Of A New Continuous Steelmaking Process, Jörg Peter

Doctoral Dissertations

"Continuous steel production has the potential to lower the cost of steelmaking as compared to current batch operations. However, experiences from past attempts to develop and commercialize continuous steelmaking processes show that there are several engineering hurdles to overcome. The objective of this research was the development of a fully continuous steelmaking process that would incorporate the lessons from past experiences, address the foreseen challenges, and meet the requirements to justify the possible replacement of the current EAF-LMF steelmaking route.

The design of the new process consists of five interconnected vessels. Preheated scrap would be continuously charged, melted, and superheated …

Nanodot-Based Organic Memory Devices, Zhengchun Liu

Doctoral Dissertations

In this study, resistor-type, diode-type, and transistor-type organic memory devices were investigated, aiming at the low-cost plastic integrated circuit applications. A series of solution-processing techniques including spin-coating, inkjet printing, and self-assembly were employed to fabricate these devices.

The organic resistive memory device is based on a novel molecular complex film composed of tetracyanoquinodimethane (TCNQ) and a soluble methanofullerene derivative [6,6]-phenyl C61-butyric acid methyl ester (PCBM). It has an Al/molecules/Al sandwich structure. The molecular layer was formed by spin-coating technique instead of expensive vacuum deposition method. The current-voltage characteristics show that the device switches from the initial 'low' conduction state to …

An Analysis And Policy Implications Of Comfort Levels Of Diverse Constituents With Reported Units For Blast Vibrations And Limits: Closing The Communication Gap, Braden Lusk

Doctoral Dissertations

"Differences exist between public perception of construction blasting and quarry blasting. In general, people are able to tolerate short term inconveniences much better than long term ones. Quarries and other long term mining operations utilizing blasting are coming under increasing public and legislative pressure in the United States. The question being posed for the blasting industry is, "Has our past haste in adopting complex scientific scales and units been detrimental to us?" In other words, are the most palatable things being reported? The goal of this dissertation is to determine whether current units create an atmosphere of discomfort among neighbors …

Evaluation Of The Effect Of Vehicle Performance On Consumer Satisfaction, Elizabeth A. Cudney

Doctoral Dissertations

"Value is the relationship of functionality or benefit to the cost of a product or service. Consumers appear to seek value, but not all consumers are alike in their needs and wants. Common characteristics that consumers desire in automobiles include a high level of value relative to the product's cost. Consumers measure vehicle performance in terms of twenty-three attributes such as roominess, ride, reliability, handling, brake pedal feel, visibility, interior noise, acceleration, etc. Problems arise when automakers try to translate these characteristics into vehicle performance specifications and capabilities.

Quality is an essential element for both the consumer and producer since …

Integration Of Micro Nano And Bio Technologies With Layer -By -Layer Self -Assembly, Dinesh Shankar Kommireddy

Doctoral Dissertations

In the past decade, layer-by-layer (LbL) nanoassembly has been used as a tool for immobilization and surface modification of materials with applications in biology and physical sciences. Often, in such applications, LbL assembly is integrated with various techniques to form functional surface coatings and immobilized matrices. In this work, integration of LbL with microfabrication and microfluidics, and tissue engineering are explored. In an effort to integrate microfabrication with LbL nanoassembly, microchannels were fabricated using soft-lithography and the surface of these channels was used for the immobilization of materials using LbL and laminar flow patterning. Synthesis of poly(dimethyldiallyl ammonium chloride)/poly(styrene sulfonate) …

A Fe-Fd Hybrid Scheme For Solving Parabolic Two-Step Micro Heat Transport Equations In Irregularly Shaped Three Dimensional Double -Layered Thin Films Exposed To Ultrashort -Pulse Lasers, Brian R. Barron

Doctoral Dissertations

Multi-layer thin films are important components in many micro-electronic devices. These films are often used when a single film layer is insufficient to meet devices specifications. The continued reduction in component size has the side effect of increasing the thermal stress on these films and consequently the devices they comprise. Understanding the transfer of heat-energy at the micro-scale is important for thermal processing using a pulse-laser. Often, micro-voids may be found in processed devices. This is due to thermal expansion. Such defects may cause an amplification of neighboring defects resulting in severe damage and consequently the failure of the device. …

Design And Development Of Poly -(3 -Hexylthiophene) Field Effect Transistors, Fengliang Xue

Doctoral Dissertations

Organic field effect transistors (OFETs) with poly(3-hexylthiophene) (P3HT) as the active layer are developed and studied. The device characteristics are significantly affected by source/drain contact resistance, and P3HT-SiO 2 interface and the traps. These results are verified by the numerical device simulations. The temperature dependence of device mobility is studied, which indicates that the carrier transport is either heat-assisted or heat-limited at different temperature ranges. The on/off ratio and threshold voltage are found to be dependent on the temperature. Hysteresis effect due to gate electric stress is investigated. The silanol groups present at the SiO2 surface are thought to be …

Application Of Polyelectrolyte Layer-By-Layer Nano-Assembly For Surface Modification, Encapsulation And Controlled Release, Nikhil Anil Pargaonkar

Doctoral Dissertations

In this study, we applied the traditional Electrostatic layer-by-layer (ELBL) assembly procedure to fabricate nanothin films over flat surfaces, and modify particle surfaces to influence the drug particle size, and drug release. The ELBL assembly has previously been applied to fabricate multilayer nano-scale thin films, but its ability to instantaneously influencing particle size is unique. Other unique observations such as influence on drug release as a result of polymer complexation, and thermal changes occurring during layer fabrication are recorded.

The ELBL self-assembly process was applied to produce dexamethasone particles layered with various polyelectrolyte layer combinations. These combinations were further applied …

Development Of Palladium Nanowires, Chuanding Cheng

Doctoral Dissertations

Inherent limitations of traditional lithography have prompted the search for means of achieving self-assembly of nano-scale structures and networks for the next generation of electronic and photonic devices. The nanowire, the basic building block of a nanocircuit, has recently become the focus of intense research. Reports on nanowire synthesis and assembly have appeared in the scientific literature, which include Vapor-Liquid-Solid mechanism, template-based electrochemical fabrication, solvothermal or wet chemistry, and assembly by fluid alignment or microchannel networks. An ideal approach for practical application of nanowires would circumvent technical and economic constraints of templating. Here we report on the self-assembly of highly-ordered …

Study On Poly[2-Methoxy-5-(2'-Ethylhexyloxy)-1,4-Phenylenevinylene] Polymer Based Photodetectors, Difei Qi

Doctoral Dissertations

This thesis is dedicated to the development of novel and efficient polymer photodetectors based on MEH-PPV conjugated polymers. The polymer-based photodetectors have the advantages of easy processing, low weight, and low cost, and thus are promising candidates for future generations of photodetectors. At present, the quantum efficiency of polymer photodetectors is still low and not comparable to inorganic photodetectors. Therefore, in this thesis we explore ways to enhance the quantum efficiency of polymer photodetectors by using different electron donors, configurations, and implementation of the diffraction optical grating into photodetector structure. We designed, fabricated, and characterized several original types of devices: …

Organization And Signal Processing Of The Descending Tracts In The Cervical Spinal Cord, Yanmei Tie

Doctoral Dissertations

This dissertation addresses the research for the development of spinal cord-computer interface (SCCI). The main objective of SCCI is to generate voluntary motor control signals for individuals with spinal cord injury (SCI).

In the neuroscience aspect, organization of the fibers in the descending tracts of the dorsolateral funiculus of the cervical spinal cord was investigated in cats. The spinal cord was penetrated with silicon substrate microelectrodes at 400 μm intervals in the medio-lateral direction at the C5/C6 and C6/C7 segmental borders. The stimulus consisted of a 20 ms train of charge-balanced biphasic pulses at 330 Hz. The evoked activities from …

Modeling, Design, And Validation Of Fluorescent Spherical Enzymatic Glucose Microsensors Using Nanoengineered Polyelectrolyte Coatings, Jonathan Quincy Brown

Doctoral Dissertations

In this dissertation, the modeling, design, and function of fluorescent spherical enzymatic microsensors for minimally-invasive diabetic monitoring are described. The devices reported herein are novel and their experimental construction and theoretical analysis have not been previously reported, thus laying the foundation for an intensive set of studies. These sensors are based on the encapsulation of an enzymatic fluorescent assay for glucose within hydrogel alginate microspheres with diameters on the order of tens of microns, which are of the appropriate size for intradermal implantation. A novel feature of these sensors is the use of multifunctional nanoengineered ultrathin multilayer polyelectrolyte coatings on …

Dna-Templated Assembly Of Metallic Nanowires, Qun Gu

Doctoral Dissertations

Nanowires are widely recognized as key elements in the development of futuristic nanoscale devices of nanoelectronics, optoelectronics and nano-electro-mechanic systems. Lithographic fabrication, however, faces increasing difficulties in the realization of continuously miniaturized features. The “Bottom-up” approach is a promising successor to lithography for fabrication of nanostructures. DNA is a natural template for nanowire assembly. The linear polynucleotide chain has a width of 2 nm and a length of 0.34 run per nucleoside subunit.

One-dimensional magnetic Co and Ni nanoparticles have been assembled in-situ for the first time by use of single DNA molecules as templates. Target metallic nanowires that are …

Numerical Simulation Of Nanopulse Penetration Of Biological Matter Using The Z -Transform, Shengjun Su

Doctoral Dissertations

Short duration, fast rise time ultra-wide-band (UWB) electromagnetic pulses (“nanopulses”) are generated by numerous electronic devices in use today. Moreover, many novel technologies involving nanopulses are under development and expected to become widely used soon. Study of nanopulse bioeffects is needed to probe their useful range in possible biomedical and biotechnological applications, and to ensure human safety.

Based on the well-known dispersive properties of biological matter and their expression as a summation of terms corresponding to the main polarization mechanisms, the Cole-Cole expression is commonly employed to describe the frequency dependence of the dielectric properties of a tissue. Solving the …

Application Of Self -Assembled Ultrathin Film Coatings To Stabilize Enzyme Encapsulation And Activity In Alginate Microspheres, Rohit Srivastava

Doctoral Dissertations

Alginate-based hydrogels have been used for the encapsulation of a variety of materials, including enzymes, proteins, and cells for a wide range of applications from drug delivery to biosensors and bioreactors. However, due to the high porosity of the matrix, it has been increasingly difficult to retain macromolecules inside the alginate matrix, leading to loss in functionality over time. In an effort to improve the stability for long-term biosensor use, this work investigated layer-by-layer self-assembly as a potential technique to provide a diffusion barrier to an encapsulated macromolecule. Alginate microspheres (∼2–50μm radius) were fabricated using an emulsification technique, and were …

Microencapsulation Techniques Towards Building A Sensor: A Study Of Factors Affecting Enzyme Encapsulation And Stability, Suman R. Nayak

Doctoral Dissertations

Minimally and non-invasive glucose sensing techniques are instrumental in improving the quality of life of diabetics, point-of-care testing, critical care monitoring, development of new anti-diabetic drugs or therapeutic compounds, and the study of basic physiology. The overall goal of this project was to build a fluorescent glucose sensor by incorporating relevant sensing chemistry within microcapsules. The specific aims for this research were to study various processes used for the fabrication of micro-containers, the use of these for encapsulation purposes, and the application of the encapsulated system towards glucose sensing. The following is a brief description highlighting the key areas of …

Biosensing With Microcantilever-Based Sensors, Xiaodong Yan

Doctoral Dissertations

Microcantilevers provide an ideal platform for biosensors. The micron-sized transducer brings several advantages, such as high sensitivity, small sample quantity for analysis, portability, implantable sensor devices, and the ability to be mass produced and integrated into standard microelectronic processing technologies like complementary metal oxide seminconductors (CMOS).

The objective of this research is to investigate and develop modification methods of microcanitlevers for biosensing applications.

Two microcantilever modification methods were investigated. They are self-assembly monolayer method and layer-by-layer method. A fundamental procedure for modification of microcantilevers using the layer-by-layer approach was developed for the first time in this research. These modification methods …

Development Of A Novel Microreactor For Improved Chemical Reaction Conversion, Yu Liang

Doctoral Dissertations

Microreactors have been widely studied over the past two decades for different chemical reactions, to develop new analytical capabilities, and to obtain high mixing performance in the reactors. The main objectives of this work are to investigate the effect of different microchannel structures on the fluid properties and mixing behavior in microreactors, and to design, fabricate, and test a novel microreactor for higher conversion in a chemical reaction. The development of this novel microreactor is intended to provide a valuable guideline in achieving enhanced chemical mixing and to make available a solid research base for optimization of the yield of …

A Numerical Method For Obtaining An Optimal Temperature Distribution In A 3d Triple-Layered Cylindrical Skin Structure, Le Zhang

Doctoral Dissertations

In recent years, it has been interesting to research hyperthermia combined with radiation and cytotoxic drugs to enhance the killing of tumors. The crucial problem is that when heating the tumor tissues, one needs to keep the surrounding normal tissue below a temperature that will produce harm. Thus, it is important to obtain the temperature field of the entire treatment region. The objective of this dissertation is to develop a numerical model for obtaining an optimal temperature distribution in a 3D triple-layered cylindrical skin structure. To this end, we pre-specify the temperatures to be obtained at the center and perimeter …

Intelligent Control Of Nonlinear Systems With Actuator Saturation Using Neural Networks, Wenzhi Gao

Doctoral Dissertations

Common actuator nonlinearities such as saturation, deadzone, backlash, and hysteresis are unavoidable in practical industrial control systems, such as computer numerical control (CNC) machines, xy-positioning tables, robot manipulators, overhead crane mechanisms, and more. When the actuator nonlinearities exist in control systems, they may exhibit relatively large steady-state tracking error or even oscillations, cause the closed-loop system instability, and degrade the overall system performance. Proportional-derivative (PD) controller has observed limit cycles if the actuator nonlinearity is not compensated well. The problems are particularly exacerbated when the required accuracy is high, as in micropositioning devices. Due to the non-analytic nature of the …

Dilation Of The Oropharynx Via Selective Stimulation Of The Hypoglossal Nerve, Jingtao Huang

Doctoral Dissertations

Obstructive sleep apnea (OSA) is caused by the retraction of the tongue to occlude the upper airway (UAW). Electrical stimulation of the tongue protrudor and retractor muscle has been demonstrated as an effective technique to alleviate UAW obstructions and is considered to be a potential treatment for OSA. Recent studies have shown that selective stimulation of the hypoglossal nerve (HG) to activate tongue muscles using a single implantable device presents an attractive approach for treating OSA. In this study, the functional outcome of selective hypoglossal nerve stimulation with a multi-contact peripheral nerve electrode was studied by imaging the airway in …

Cad Model Extraction Of Pcb Signal Discontinuity Using A Circuit Extraction Approach Based On Mixed-Potential Integral Equation Formulation, Shaofeng Luan

Doctoral Dissertations

"In high-speed digital design, signal via transitions on printed circuit boards (PCBs) are becoming an important signal integrity issue. Efficient and accurate models for via transitions are necessary to analyze high bit-rate digital circuit system. The circuit extraction approach based on a mixed-potential integral equation formulation (CEMPIE) is an extension of the Partial Element Equivalent Circuit approach (PEEC) to general multi-layered media. CEMPIE was further developed to include the horizontal current components on the vertical surface and extended to model the discontinuities on multilayer PCBs. A procedure of building SPICE models for signal via transitions between printed circuit board layers …

Polymer-Based Wide-Angle Micro -Optic Lens System With Dynamically Variable Focal Length And Field Of View, Mangilal Agarwal

Doctoral Dissertations

A novel polymer-based integrated wide-angle dynamic micro-optical lens system that can provide variable focal length and field of view (FOV) with large numerical aperture is designed, fabricated, and tested for its optical characteristics.

Initial experiments were conducted using static glass lenses to test for configuration of lenses that could provide wide FOV. From these initial experiments, it was found that the higher FOV could be achieved with double concave (DCV) lenses compared to double convex (DCX) lenses of the same focal length. Further, it was observed that increasing the number of DCV lenses increases FOV. Thus, an integrated dynamic polymer …

Layer-By-Layer Self -Assembly For Enzyme And Dna Encapsulation And Delivery, Amish Patel

Doctoral Dissertations

Thin wall microcapsules were formed via Layer-by-Layer Self-Assembly of alternate adsorption of oppositely charged polyelectrolyte on microcores. After the core dissolution, empty polymeric shells with 20–25 nm thick walls were obtained. These microcapsules were loaded with Myoglobin, Hemoglobin and Glucose Oxidase by opening capsule pores at low pH and closing them at higher pH. The native structure of the enzyme was not affected due to different treatments. Biocompatible nanoshells were also prepared for encasing DNA. Using the same Layer-by-Layer Self-Assembly approach nanoparticle were constructed containing DNA as one of the layers. The nanoparticles of different architecture were used to deliver …

Layer-By-Layer Nanoassembly Combined With Microfabrication Techniques For Microelectronics And Microelectromechanical Systems, Jingshi Shi

Doctoral Dissertations

The objective of this work is to investigate the combination of layer-by-layer self-assembly with microfabrication technology and its applications in microelectronics and MEMS.

One can assemble, on a standard silicon wafer, needed multilayers containing different nanoparticles and polymers and then apply various micromanufacturing techniques to form microdevices with nanostructured elements.

Alternate layer-by-layer self-assembly of linear polyions and colloidal silica at elevated temperatures have been firstly studied by QCM and SEM. LbL self-assembly and photolithography were combined to fabricate an indium resistor. The RTA method was employed in the fabrication. Hot-embossing technique as a reasonably fast and moderately expensive technique was …

Biomimetic Synthesis Within Polyelectrolyte Microcapsules: Characterization Of Enzyme Catalyzed Polyphenols And Polypeptides, Rohit C. Ghan

Doctoral Dissertations

An enzyme-catalyzed synthesis of novel polymers within layer-by-layer (LbL) constructed polyelectrolyte microcapsules has been developed. This approach is based on the selective permeability of polyelectrolyte-capsule walls to monomer molecules. Conversely biocatalysts and forming polymeric chains cannot exit the micro-capsule interior because of their characteristic high molecular weight. Horseradish Peroxidase (HRP) was encapsulated into four bilayer PSS (poly-styrenesulfonate)/PAH (poly-allylamine hydrochloride) capsules with an average diameter of 5 μm using pH-driven pore opening. The polymerization of 4-(2-Aminoethyl) phenol hydrochloride (tyramine) catalyzed by HRP produces easily detectable fluorescent polymeric products after the addition of hydrogen peroxide to the system. It is known that …