Digital Commons Network^™

Sounding Rocket Measurements Of Thermal Electrons In Active Nightside Aurora, Elizabeth Macdonald

Doctoral Dissertations

On January 14th 2002 the SIERRA sounding rocket was launched from Poker Flat Research Range, Alaska into active substorm expansion aurora and reached 735 km. For the first time, direct measurements of the cold ionospheric population in darkness were made by the UNH Thermal Electron Detector (TED). At these middle altitudes, understanding this population is important because the thermal electrons can carry currents coupling the lower ionosphere and the magnetospheric auroral source. This thesis, focusing on the development and analysis of this new instrument, incorporates the study of two distinct areas. One area is the direct measurement of the ambient …

A Three-Level Finite Difference Scheme For Solving A Dual-Phase-Lagging Heat Transport Equation In Spherical Coordinates, Lixin Shen

Doctoral Dissertations

Heat transport through thin films or micro-objects is of vital importance in microtechnology applications. For instance, metal thin films are important components of microelectronic devices. The reduction of the device size to microscale has the advantage of enhancing the switching speed of the device. On the other hand, size reduction increases the rate of heat generation, which leads to a high thermal load on the microelectronic devices. Heat transfer at the microscale is also important for the thermal possessing of materials with a pulsed-laser. Examples in metal processing are laser micromachining, laser patterning, laser processing of diamond films from carbon …

Organic Diodes, Field -Effect Transistors, And An Inverter Circuit By Microfabrication Techniques, Guirong Liang

Doctoral Dissertations

The objective of this work is to fabricate microelectronic devices and circuits based on organic and polymer materials by micro fabrication techniques.

The organic microelectronic device is one of the most promising alternative to traditional inorganic devices due to its varieties of advantages, such as low-cost, large area (e.g. for display), and distinguished mechanical property (insensitive to mechanical deformation). For practical applications, it is necessary to reduce the fabrication cost as well as to improve the device's performance. In this work several fabrication processes have been developed to build organic diodes, field-effect transistors (FETs) and circuits.

Simple spin coating and …

Polymer-Based Capacitors, Junction Field -Effect Transistors, And A Follower Circuit By Lithography, Self -Assembly, And Ink -Jet Printing Techniques, Yuxin Liu

Doctoral Dissertations

The study of organic materials to create field-effect transistors has recently emerged and is gaining much interest. All-polymer electronic devices are currently in their infancy, like semiconductor devices when they first appeared. As a result, current performance of these devices is in no way comparable to the state-of-the-art semiconductor devices. However, all-polymer devices have a few possible appealing advantages. First, all polymer devices have the potential for low-cost fabrication due to their ease of manufacturability, with fewer and simpler processing steps compared with solid-state semiconductor devices. Secondly, polymer devices offer the ability of material flexibility. Lastly, polymer devices may prove …

Patterning Layer -By -Layer Self -Assembled Multilayer By Lithography And Its Applications To Thin Film Devices, Feng Hua

Doctoral Dissertations

Nanoparticles are exciting materials because they exhibit unique electronic, catalytic, and optical properties. As a novel and promising nanobuilding block, it attracts considerable research efforts in its integration into a wide variety of thin film devices.

Nanoparticles were adsorbed onto the substrate with layer-by-layer self-assembly which becomes of great interest due to its suitability in colloid particle assembly. Without extremely high temperatures and sophisticated equipment, molecularly organized films in an exactly pre-designed order can grow on almost all the substrates in nature.

Two approaches generating spatially separated patterns comprised of nanoparticles are demonstrated, as well as two approaches patterning more …

Modeling Of The Inverse Heat -Conduction Problem With Application To Laser Chemical Vapor Deposition And Bioheat Transfer, Peng Zhen

Doctoral Dissertations

This dissertation consists of two parts. Part one deals with three-dimensional laser induced chemical vapor deposition (3D-LCVD), whereas part two deals with a Pennes model of a 3D skin structure. LCVD is an important technique in manufacturing complex micro-structures with high aspect ratio. In part one, a numerical model was developed for simulating kinetically-limited growth of an axisymmetric cylindrical rod by pre-specifying the surface temperature distribution required for growing the rod and then by obtaining optimized laser power that gives rise to the pre-specified temperature distribution. The temperature distribution at the surface of the rod was assumed to be at …

Fabrication Of Cell Culture Scaffolds Using Micro/Nanotechnologies To Study The Attachment And Alignment Of Smooth Muscle Cells, Mengyan Li

Doctoral Dissertations

This dissertation elaborates the design and fabrication of in vitro cell culture scaffolds using microfabrication and electrostatic layer-by-layer self-assembly (LbL) technologies, and develops the so-called layer-by-layer lift-off (LbL-LO) technique to control surface topography, surface properties, and underlying architectures of the scaffolds. Smooth muscle cells were cultured on the fabricated scaffolds with gelatin, fibronectin, and polyelectrolytes (PSS, PDDA, PAH, and PEI) as surface materials, multilayer polyelectrolytes as architectures, deposited in strip- and square-patterns. It was found that the exposed surface materials, which have different charge, hydrophobicity, and chemical structure (e.g., amino acid sequence), affect the adhesion of smooth muscle cells. Cells …

Design And Fabrication Of A Novel Linear Oscillating Conventional Micro Air Pump, Shi-Je Wu

Doctoral Dissertations

A novel permanent magnetically and electro-magnetically powered, linear oscillating conventional micro air pump was designed, fabricated and characterized. This new pump might be used in a wrist-type blood pressure monitor or other similar devices that require high air pressure discharge. Factors considered in designing this micro air pump include feature size (especially the thickness), operation voltage, efficiency, heat transfer, noise and weight. For evaluating the feasibility of this novel design, basic performance calculations and ANSYS magnetic flux simulations had been conducted before the first prototype was made. Both theoretical calculations and simulation results show that this novel design meets the …

Finite Element Analysis And Statistical Modeling Of Pipeline Rehabilitation Liners With Material Imperfections, Wei Zhao

Doctoral Dissertations

Thin-walled plastic liners are routinely used to rehabilitate structurally sound host pipes that have lost their hydraulic integrity. The liner/host pipe structure is treated as a ring encased in a rigid wall. Significant research work dealing with liner stability has been completed in North America and Europe. These research works include laboratory experiments, numerical analysis, and statistical modeling. The objective of this dissertation is to achieve a better understanding of liner buckling phenomenon using the finite element method and statistical analysis.

Short-term liner buckling models have been applied by several researchers to study the influence of liner geometric imperfections on …

A Lateral Comb Drive On Pmma By Hot Embossing Technique, Yongjun Zhao

Doctoral Dissertations

The objective of this work is to fabricate a laterally driven comb drive on low-cost poly-methyl-meth-acrylate (PMMA) by hot embossing technology.

An electrostatic comb drive is one of the most important components in Micro-Electro-Mechanical Systems (MEMS). A comb drive can work as both a sensor and an actuator. Varieties of comb drives have been developed on silicon and poly-silicon materials.

Hot embossing of polymers is a promising alternative to traditional silicon processes due to cost-reduction. It fulfills the demand for low-cost methods for high volume production of micro-components and micro-systems. The raw materials of polymer are relatively inexpensive. For the …

Antecedents Of Salesperson Effectiveness And Efficiency Performance: A Data Envelopment Analysis, Xueming Luo

Doctoral Dissertations

The objective of this dissertation was to (1) measure salesperson efficiency; (2) investigate both personal and organizational factors that determine salesperson efficiency; and (3) investigate both personal and organizational factors that determine salesperson effectiveness. Salesperson efficiency was assessed by data envelopment analysis (DEA). Two different DEA models were employed in order to increase the reliability of the efficiency results. Antecedents of salesperson efficiency and effectiveness were tested using Tobit regression analysis and ordinary least square regression analysis, respectively. These antecedents include not only personal level variables such as working smart, working hard, learning goal orientation, and performance goal orientation, but …

Vertical Polymer Tunneling Sensor Platform By Hot Embossing Technique, Jing Wang

Doctoral Dissertations

Recent development in microfabrication technology has brought much attention to the development of miniaturized, inexpensive and high-accuracy MEMS devices and microsystems. The ultimate goal of our project is to develop a versatile, three-dimensional, high precision sensor platform, which can be used for displacement, velocity or acceleration measurement. The first step, on which this dissertation is based, is to fabricate a one-dimensional (parallel with the Z axis) tunneling sensor, which in turn can be developed into two- and three-dimensional sensor platforms through structural and functional integration.

Since the invention of mini-structured high-sensitivity silicon-based tunneling sensor in 1993, the synthesis and fabrication …

Nanoscale Platinum And Iron -Cobalt Catalysts Deposited In Microchannel Microreactors For Use In Hydrogenation And Dehydrogenation Of Cyclohexene, Selective Oxidation Of Carbon Monoxide And Fischer -Tropsch Process To Higher Alkanes, Shihuai Zhao

Doctoral Dissertations

Chemical Process Miniaturization (CPM) has predominant advantages in heat and mass transfer limited unit operations, synthesis of hazardous materials, and as a process development tool. For years, engineers have been seeking ways to apply CPM to practical applications. Studies of catalysts and catalyst supports that can be applied to microreactors are important for a number of commercially desirable gas phase reactions. Parameters such as surface-to-volume ratio and the pore structure of catalyst supports influence the activity and selectivity of the catalysts.

In this study, platinum, iron and cobalt catalysts were fabricated by sputtering deposition and compared with catalysts deposited by …

Effects Of Diabetes And Aging On Posture And Acceleration Thresholds During Lateral Translations, Samantha Jean Richerson

Doctoral Dissertations

Research objectives. One source of falls in the elderly may be an inability to sufficiently adjust to transient postural perturbations or slips. Identifying useful predictors of fall potential, as well as factors that affect the ability of an individual to detect a movement of the standing support surface may provide insight into postural stability and methods to increase stability in elders. To do this, acceleration thresholds to short, precise, lateral platform translations and the resultant psychophysical responses of adults with early Type 2 diabetes to age-matched controls and young adults were measured.

Methods. Using an innovative SLIP-FALLS platform, …

Understanding Wavelet Analysis And Filters For Engineering Applications, Chethan Bangalore Parameswariah

Doctoral Dissertations

Wavelets are signal-processing tools that have been of interest due to their characteristics and properties. Clear understanding of wavelets and their properties are a key to successful applications. Many theoretical and application-oriented papers have been written. Yet the choice of a right wavelet for a given application is an ongoing quest that has not been satisfactorily answered. This research has successfully identified certain issues, and an effort has been made to provide an understanding of wavelets by studying the wavelet filters in terms of their pole-zero and magnitude-phase characteristics. The magnitude characteristics of these filters have flat responses in both …

Study Of Energy Sampling Weights In The Dø Detector Using Multiparameter Fitting Method, Qun Yu

Doctoral Dissertations

The DØ calorimeter at Fermilab is a sampling calorimeter measuring the energy of particles produced in high energy proton-antiproton collisions. A set of accurate sampling weights is of significant importance to DØ research activity. The objective of this work was to obtain a set of optimized sampling weights for the DØ central calorimeter, the Inter-Cryostat Detector (ICD), the Central Calorimeter Massless Gap (CCMG), and the End Calorimeter Massless Gap (ECMG).

The foundation of the optimization method is that, in high energy physics, the ratio of energy E and the corresponding momentum P of a particle is approximately 1, in units …

Design And Fabrication Of A Microscale Joule -Thomson Refrigerator, Lionel Gamini Hewavitharana

Doctoral Dissertations

A simple thermodynamic, heat transfer, and fluid flow model was developed for microscale Joule-Thomson refrigerators (JT devices). For a given geometry, the model predicted that the cooling capacity of the refrigerator increased with the inlet refrigerant pressure. The effectiveness of the JT device also increased with the inlet pressure, and the heat exchanger channel length. At a constant inlet pressure, the effectiveness, and the refrigeration capacity of a given JT device increased as the aspect ratio of heat exchanger channels was increased. For nitrogen refrigerant, the model predicted that it was possible to obtain approximately 250 mW of refrigeration capacity …

Microreactor System With Immobilized Enzyme On Polydimethylsiloxane (Pdms) Polymers, Zonghuan Lu

Doctoral Dissertations

Microsystems, specifically microreactors, open the gate to new, improved analytical techniques while offering many advantages for a large number of applications in chemical engineering, pharmacy, medicine, and biotechnology. This study explored the feasibility of fabrication of microreactors using polydimethylsiloxane (PDMS) as a support for enzyme immobilization. Urease enzyme was used for catalyzing the conversion of urea to ammonia.

PDMS (polydimethylsiloxane) is a silicone-based elastomeric polymer. Traditional micromanufacturing technology was employed for reactor mold fabrication. The mold was fabricated based on photolithography techniques, and SU-8 photoresist was used to construct reactor structure templates. The resulting silicon-wafer based reactor molds were then …

A Comparison Of Floristic Diversity In Old-Growth Versus Mid-Successional Secondary-Growth Hardwood Forests Of The White Mountain National Forest, New Hampshire, United States, Leslie Marie Teeling-Adams

Doctoral Dissertations

There is currently debate over whether managed forests will ever regain the species diversity of old-growth stands. While succession and response to disturbance of tree species has been extensively researched, little similar effort has focused on understory herbaceous communities. This study conducted large-scale, comprehensive botanical inventories of three old-growth and three mid-successional (80--100 year old) secondary forest stands in New Hampshire's White Mountain National Forest (WMNF). Cluster analysis and TWINSPAN grouped the secondary sites within two steps. Old-growth floras were significantly richer in total, total herbaceous, woodland herbaceous, and unique herbaceous species. Abundance distributions of the two treatment groups were …

Towards More Efficient Solution Of Conditional Constraint Satisfaction Problems, Mihaela Sabin

Doctoral Dissertations

The focus of the thesis is on improving solving constraint satisfaction problems (CSPs) that change with certain conditions. This special class of problems, which we call conditional CSPs, has proved very useful in modeling important applications, such product configuration and design, and distributed software diagnosis and network management. The problem conditions model choices customers make to configure a product, or they are installation settings or actual observations of a running system that is monitored for diagnosis purpose.

The key, novel contribution of this thesis are two approaches for improving solving methods and the use of random conditional CSPs to evaluate …

Design And In Situ Testing Of A Piezometer System To Measure Earthquake -Induced Pore -Pressure Changes, Robert Farrell

Doctoral Dissertations

Pore pressure changes have been measured in fine sand deposits that are known to have liquefied during earthquakes. Some of the measured signals have not been similar to what was expected during earthquake-induced liquefaction. Using artificially generated signals, several investigators have attempted to determine if existing piezometer fields designed to measure earthquake induced pore pressure changes are operating correctly. The signals generated during one investigation were not similar to those expected from an earthquake. In another investigation, while the generated signals were similar to ones expected from an earthquake, the results were not reproducible; the generated signals damaged the aquifer …

Introducing Performance Into The Communication Curriculum For Engineers: Breaking The Mould, Constance Matilda Israel

Doctoral Dissertations

Education in South Africa has, thankfully, not escaped the winds of change. The introduction of Outcomes-based Education (OBE) has generated much debate. How have technikons responded to the educational transformation impelled by sociopolitical change? I refer here specifically to the Communication curricula for engineers at Mangosuthu Technikon.

This research explores the effects in my Communication classroom of introducing performance, through games and a dramatic text. My intention is to subvert the potential dangers of OBE, given its behaviourist and prescriptive thrust, and a possible reversion to the transmission model in its application at Mantec. I argue that gaps in the …

Satellite Indices Of Fluvial Influence In Coastal Waters, Joseph E. Salisbury Ii.

Doctoral Dissertations

In this dissertation a suite of satellite, discharge and in-situ measurements is used to explore the spatio-temporal distribution of terrestrial constituents in coastal environments. The covariance between riverine delivery of optically active constituents and the corresponding optical variability in neighboring coastal waters for the Mississippi and Orinoco Rivers is documented. From this work, satellite-based indices of fluvial influence (IFI), are developed which contain information on the spatial extent of riverine constituents in coastal waters. The IFI is defined as the correlation between time series of riverine discharge and an ocean color satellite-derived property in the region proximal to a river's …

Spatial Modeling And Visualization Of Habitat Response To Hydrologic Restoration In New England Salt Marshes, Raymond Anthony Konisky

Doctoral Dissertations

Anthropogenic alterations that restrict tidal flows negatively impact 20% of New England salt marshes, but management attempts to restore tides to these sites can be met with unexpected or less than optimal results. Restoration planners may be hindered by a lack of synthesized information regarding important biotic and abiotic factors that determine the distribution of dominant salt marsh plants and invasive species. An ecosystem model was developed to better predict salt marsh habitat response to hydrologic modification as a synthesis of existing models for biomass production, marsh elevation, tidal hydrology, and plant succession. A field experiment was conducted to provide …

Living The Stereotype: Connections Between Male Behavior And Male Images, Andrew Paul Smiler

Doctoral Dissertations

This project examined some linkages and discrepancies between theories that describe the acquisition of gender typical attributes in childhood with theories that describe the maintenance of those attributes in adulthood. This perspective included the idea that there are several well known ways of enacting masculinity, related to well known stereotypes (e.g., jock, business, sensitive new age guy), and highlighted within sex variability. Because a distinction between biological sex and gender was made, the sample was not restricted to males despite focusing on the masculine. One focus of the project was the consistency with which an individual enacts a particular stereotypical …

Assessment Of The Fate Of Cryptosporidium Parvum, Giardia Lamblia And Ascaris Lumbricoides In Class A Composting And Class B Lime Stabilization Biosolids Treatment Processes, Christine L. Bean

Doctoral Dissertations

The management of biosolids in the United States has become an issue of public health concern in regard to disposal. Congress created the Clean Water Act in 1972 to protect waters in the United States and as a result, no longer can human waste be dumped into oceans or rivers. Means of disposal of biosolids are focused on land application today. The practice of land application takes into consideration the classification of the biosolids material and management practices to control access to and growth of crops on the land. Biosolids are classified as either Class A or Class B depending …

Thermal Rearrangements Of Linear Carbon Chains: Theoretical And Experimental Studies, John Mabry

Doctoral Dissertations

The potential energy surface of linear hydrocarbons has been extensively investigated by experiments and the use of molecular modeling. Linear C4 structures have demonstrated the potential to scramble their inner carbon atoms leading to the formation of novel strained intermediates.

Long-range carbon atom topomerization in a 1,3-diyne has been demonstrated for the first time. 1-Phenyl-4-p-tolyl-1,3-butadiene, 13C enriched at C-1, was synthesized and subjected to flash vacuum pyrolysis. Under high temperature and at low pressure, this resulted in nearly complete 13C label equilibration among all of the sp hybridized carbons, as seen by NMR analysis. It has been proposed that 1,3-diynes …

Wavelet Analysis Of Ulf Magnetospheric Waves, Edward Scott Brennison

Doctoral Dissertations

Wavelet analysis is used to analyze magnetometer data and is compared to the traditional spectrogram technique, in particular, with respect to structured Pc 1--2 emissions. This results in the conclusion that the frequency modulation evident in Pearl pulsations is not continuous, but is comprised of waves localized in both time and space whose overall structure produces the stripe-like patterns. Utilizing information from the Multi-Resolution Analysis in conjunction with traditional spectrogram techniques this paper is the first to show clear signal power relationships between Pc 1--2 and Pc3 waves and also between Pc 1--2 and Pc 5 waves as detected on …

The Impact Of Coating Architecture On The Hardness, Friction And Wear Resistance Of Hard And Tribological Nanocomposite Coatings, Jose Luis Endrino

Doctoral Dissertations

Future generations of mechanical systems will place new demands on the tribological performance of interacting surfaces. Vapor-deposited surface coatings can provide extended lifetimes, increased efficiencies and energy savings for mechanical components and tools. These benefits can also be extended to space mechanisms and satellites with the use of vacuum solid lubricants. The material properties of surface coatings such as hardness, friction, and wear resistance in a particular environment are influenced by the characteristics of the coating microstructure which include density, grain size, grain boundary chemistry, porosity, and grain orientation.

In this research effort bias sputter deposition, co-sputtering, and magnetron sputtering-pulsed …

In-Situ Study Of The Influence Of Additives On The Growth Behavior Of Copper Electrodeposits On Copper Single Crystal, Aiwen Wu

Doctoral Dissertations

Trace organic additives are known to be essential in obtaining desired metal electrodeposits in the microelectronic industry, however, fundamental design principles for their use and a scientific understanding of their interaction during electrodeposition is lacking. In the present study we investigated electrodeposition of copper on the Cu(100) surface in air-saturated or dearated acid-sulfate plating solutions containing several combinations of chloride and additives benzotriazole (BTA) and 3-mercapto propane sulfonic acid (MPSA) under galvanostatic pulse-current conditions. The electrodeposition process was followed using in-situ atomic force microscopy (AFM). AFM images were quantitatively analyzed by pattern-recognition and scaling procedures.

In the absence of additives, …