Digital Commons Network^™

Design And Performance Of A 1 Meter Scale Horizontal Axis Wind Turbine Model, Samuel Babineau Cole

Master's Theses and Capstones

A research wind turbine of one-meter diameter was designed for the use in the UNH Flow Physics Facility (FPF), a large flow physics quality boundary layer wind tunnel. The turbine design was carried out as an aero-servo model of the NREL 5MW reference turbine, with some modifications. The turbine is used to obtain data for multiscale wake model verification and validation, including wake data over long distances downstream. Blockage in the FPF test section is 4.8% based on rotor swept area.

The rotor was designed using blade element momentum theory based on the S801 airfoil. The optimal blade chord was …

Response Of The Pui Distribution To Variable Solar Wind Conditions, Jonathan Slade Bower

Master's Theses and Capstones

We present the first systematic analysis to determine pickup ion (PUI) cutoff speed variations, during general compression regions identified by their structure, shock fronts, and times of highly variable solar wind (SW) speed or magnetic field strength. This study is motivated by the attempt to remove or correct for these effects on the determination of the longitude of the interstellar neutral gas flow from the flow pattern related variation of the PUI cutoff with ecliptic longitude. At the same time, this study sheds light on the physical mechanisms that lead to energy transfer between the SW and the embedded PUI …

Molecular Dynamics Simulations Of A Pentacene Derivative On Gold Surfaces In The Quantum Mechanical And Classical Mechanics Frameworks, Ryan Allen Miller

Master's Theses and Capstones

With increasing potential to serve as a basis for constructing organic photovoltaic de- vices, the directed self-assembly of small organic molecules on metal substrates provides an interesting new method of bottom-up device building. By utilizing the qualities inherent in the substrate and molecules, one can manipulate surface topology to create functional layers of molecules in a desired configuration. However, tailoring these organic layers in a useful way requires detailed analysis of the substructure characteristics. With top-down visualization approaches like Scanning Tunneling Microscopy (STM) pro- viding a limited view of assembled layer structural characteristics, molecular dynamics sim- ulations must be employed …

The Synthesis And Characterization Of Iron Nanoparticles, Tyler Paul Bennett

Master's Theses and Capstones

Nanoparticle synthesis has garnered attention for technological applications for catalysts, industrial processing, and medical applications. The size ranges for these is in the particles nanostructural domain. Pure iron nanoparticles have been of particular interest for their reactivity and relative biological inertness. Applications include cancer treatment and carrying medicine to a relevant site. Unfortunately, because of their reactivity, pure iron nanoparticles have been difficult to study. This is because of their accelerated tendency to form oxides in air, due to the increased surface area to volume ratio. Using synthesis processes with polyphenols or long chain amines, air stable iron nanoparticles have …

Streamline Geometry Analysis Of Turbulent Fluid Flows, Michael Dunstan

Master's Theses and Capstones

Energy in turbulent flows is transported down coherent vortical structures of different shapes and sizes. Experiments have shown that the vortical structures contain field lines that are curved in nature. Several procedures have been investigated to determine the size and location of the coherent vortical motions, as of yet there has not been a widely accepted method that exactly depicts these structures. Among the current methods of determining the coherent features of the flow, structures determined by the second largest eigenvalue of the symmetric part of the gradient of the Navier-Stokes equation has received recent attention. Another method proposed is …

A Statistical Analysis For Estimating Fish Number Density With The Use Of A Multibeam Echosounder, Madeline L. Schroth-Miller

Master's Theses and Capstones

Fish number density can be estimated from the normalized second moment of acoustic backscatter intensity [Denbigh et al., J. Acoust. Soc. Am. 90, 457-469 (1991)]. This method assumes that the distribution of fish scattering amplitudes is known and that the fish are randomly distributed following a Poisson volume distribution within regions of constant density. It is most useful at low fish densities, relative to the resolution of the acoustic device being used, since the estimators quickly become noisy as the number of fish per resolution cell increases. New models that include noise contributions are considered. The methods were applied to …

Energy Resolution Analysis Of A Domestic Neutron Imager, Marissa Louise Rousseau

Master's Theses and Capstones

The calibration and correction of the Neutron Spectroscope (NSPECT) time-of-flight (ToF) system are presented. This instrument is a double-scatter telescope designed to detect neutrons and gamma rays for the identification and location of radioactive materials. The ToF resolution is 0.72 ns FWHM. Results are reported for the ToF characterization using data obtained in the laboratory. An anomalous feature in the gamma-ray energy spectra measured with NSPECT neutron detectors is examined.

A design based on NSPECT is proposed for the assay of spent nuclear fuel, where portability is increased in exchange for source location capabilities. The proposed modular device is modifiable …

An Investigation On The Resonance Observed In A Spirally Shielded Twinaxial Differential Pair, David Richard Levine

Master's Theses and Capstones

Spirally shielded twinaxial cable assemblies are extensively used in multi-gigabit-per-second digital telecommunications systems. Unlike ideally shielded Twinaxial cables, spirally shielded cables exhibit resonant behavior which limits system throughput.

This body of work illustrates a predictive method for determining resonant behavior in twinaxial cables through physical measurement of commercially available cables and analogous transmission line fixtures, full-wave and quasi-static simulations, and equivalent circuit analysis.

It will be shown that frequency dependent standing wave resonances in twinaxial cables are independent of cable length and dependent on cross-sectional feature sizes, dielectric properties, and spiral shield pitch.

Observational Aspects Of Imf Draping Around The Magnetosphere, Brendan S. Harris

Master's Theses and Capstones

A key parameter in determining the flow of the solar wind around the magnetosphere is the Alfven Mach number (Ma) because it determines conditions at the bow shock. High Ma approaches the gas dynamic limit of flow around the magnetosphere, while low Ma implies strong magnetic forces on the flow. We study a long interval of high Ma during the recent pronounced solar minimum 2007--2009, and derive the magnetopause and bow shock shapes from data. We compare our results with models of the magnetopause and properties of the bow shock and find that during this period, the subsolar magnetosheath was …

A Micro-Transponder For Precision Tracking Of Underwater Targets, Albert Whitaker Franzheim Iii.

Master's Theses and Capstones

A prototype micro-transponder has been designed and built to track, in real-time, the positions of objects or animals within the water column. Commercially available data storage tags, which help monitor the behavior of underwater animals, do not provide real-time interrogation and data dissemination capabilities in a form factor and acoustic frequency band acceptable for active tracking applications.

This prototype is 18.5 cm3 and weighs 43.7 g in air. It operates at an acoustic frequency of 160 kHz and uses a mixed-signal topology with low-power components and a microcontroller, which allows for firmware updates and addition of external sensors. It is …

Exploration Of A Free Space Optical Telemetry System For Formation Flying Sounding Rocket Sub-Payloads, James Gealy

Master's Theses and Capstones

The results of an exploration regarding the novel use of free-space optics (FSO) between sounding rockets and their sub-payloads are presented. This includes an evaluation of optoelectronic and optical devices against environmental and system level criteria. A preliminary test using available in-house components and bench-top equipment was also performed to determine potential distances and data rates of FSO in this environment. Using a light emitting diode with an optical power output of approximately six milliwatts, and a photomultiplier tube originally purposed for use on the Compton GRO, a pulse rate of ten kilohertz was transmitted over a distance of four-hundred …

Electron Transitions And Propagation Characteristics Of Dipolarization Fronts Observed By Cluster, Jinyoung Park

Master's Theses and Capstones

This thesis describes electron transitions at the dipolarization fronts (DPFs) observed by Cluster using high time-resolution data. The sharp electron transitions occur within the rising phase of the magnetic field component Bz normal to the magnetotail current sheet. The electron transitions provide a new constraint on the DPFs generation models that are related to reconnection. A sudden Bz rise without a small dip prior to the increase was observed suggesting that tearing instabilities in the reconnection exhaust may not be required for the generation of DPFs. Based on timing and minimum variance analysis, the DPFs are found to have a …

Modeling The Signal Processing Of A Multi-Sonar System To Determine Interference Solutions, Brian O'Donnell

Master's Theses and Capstones

The quality of a multibeam echo-sounder sonar (ES) signal used in seafloor mapping is degraded by an interfering sidescan sonar (SS) signal. The ES and SS signals occur at approximately the same time, are in the same frequency band, and arrive from approximately the same direction. The ES signal is a 2 ms continuous wave pulse with a first null bandwidth of 1 kHz centered at 187.5 kHz. The interfering SS signal is an 8 ms linear frequency modulated chirp with a bandwidth of 2.5 kHz centered at 183 kHz.

The presence and properties of the interfering SS signal are …

Evaluating The Performance Of Model-Derived Wind Forecasts At Summit, Greenland During The Summer Of 2008, Jeffrey A. Luxford

Master's Theses and Capstones

The study of atmospheric chemistry relies on data from weather models to determine how air parcels move through the atmosphere. The performance of weather models can be negatively impacted by a number of factors, many of which are present at Summit, Greenland. Meteorological observations at Summit during the summer of 2008 included profiles of wind conditions over the lowest part of the troposphere. Data from the profiles were compared to output from two weather models. It was found that both models had difficulty predicting wind speed at the 650 hPa level, roughly 300--400 m above ground level. Analysis at other …

Comments On The Relation Of M-Theory And Supergravity, Timothy C. Stamnitz

Master's Theses and Capstones

M-theory was synthesized in 1995 due to observations regarding an intricate "web-of-dualities" that relate the five superstring theories, and recognition that D=11 supergravity is both nonperturbatively dual to type-IIA superstring and the low-energy limit of an 11-dimensional theory. Mutual development of M-theory and supergravity ensued.

During the past three years, related but independent field theory calculations suggest that N=8 d=4 supergravity scattering amplitudes may be ultraviolet finite. Since supergravity theories represent the low-energy effective actions of string theories and describe the interaction of massless fields in the string theory spectrum, it is noteworthy that it was suggested recently that N=8 …

Numerical And Adaptive Grid Methods For Ideal Magnetohydrodynamics, Burlen Loring

Master's Theses and Capstones

In this thesis numerical finite difference methods for ideal magnetohydrodynamics (MHD) are investigated. A review of the relevant physics, essential for interpreting the results of numerical solutions and constructing validation cases, is presented. This review includes a discusion of the propagation of small amplitude waves in the MHD system as well as a thorough discussion of MHD shocks, contacts and rarefactions and how they can be pieced together to obtain a solutions to the MHD Riemann problem. Numerical issues relevant to the MHD system such as: the loss of nonlinear numerical stability in the presence of discontinuous solutions, the introduction …

The Reduction Of Broadband Crosstalk Interference Between Multiple Conductors In A Backplane Interconnect And Its Performance Impact On Gigabit Digital Communication Signals, Prescott Brandon Atkinson

Master's Theses and Capstones

Crosstalk interference from signal transmission between transmission line conductors limits channel throughput as amplitude distortion in an experimental backplane connector. Shared return conductor microstrip connectors arranged in stacks have resonant frequencies that are determined largely by cavity dimensions of the return conductor geometries. If an input waveform to the connector excites these resonant frequencies, the resonant energy will couple to other signal conductors in the connector and will result in crosstalk interference. Lossy materials can be used to reduce the resonant crosstalk interference in connectors.

Quasi-conductor and magnetic absorber materials were used to reduce the resonant crosstalk in an experimental …

Testing And Calibration Of The Ibex Lo-Res Collimator, Stephen Zaffke

Master's Theses and Capstones

The Interstellar Boundary Explorer (IBEX) mission will provide full sky images of Energetic Neutral Atoms (ENA's) from interstellar space. The Collimator is tasked to restrict the Field of View (FOV) of IBEX, as well as repel ions up to 10keV in energy to a degree greater than 10.

4, and electrons up to 600eVto the same degree. This thesis retests the capability of the Collimator to perform these functions, as well as improving upon the testing procedures.

Design Of Atmospheric Pressure Plasma Cvd Process For Deposition Of Silicon Nitride Thin Films Using Dielectric Barrier Discharge, Shunfu Hu

Master's Theses and Capstones

Amorphous silicon nitride with incorporated hydrogen has been widely used as the anti-reflection coating for solar cells. However, current solar industry processes for silicon nitride are mainly deposited under expensive vacuum environments which are also batch type processes. Silicon nitride deposited in atmospheric pressure plasma is needed to reduce the cost of solar cells.

A dielectric barrier discharge (DBD) can be used to deposit thin films under atmospheric pressure. In this thesis, a new atmospheric pressure plasma deposition system was built and silicon nitride films were deposited on 4 by 4 inches polycrystalline silicon wafers, 3 inches single crystalline silicon …

Generation And Measurement Of Surface Plasmon Coupled Emission, Kathleen E. Hamilton

Master's Theses and Capstones

Surface plasmon coupled emission (SPCE) is a process by which isotropic fluorescent emission, from a fluorescent dye or biological agent labeled with a fluorescent dye, is channeled into highly directional emission. This process relies on the interaction between fluorescent dye molecules and thin silver films in close proximity to each other. Recent studies have shown that SPCE greatly increases the sensitivity of spectroscopic methods by increasing the amount of light that can be collected from a fluorescent molecule. The work described in this thesis encompasses the study of new materials for SPCE sample manufacture as well as the design and …

Kaon Nucleon Scattering In Lattice Qcd, Anthony Charles Marcolongo

Master's Theses and Capstones

In this paper I discuss why one would want to study meson baryon interactions within the framework of lattice QCD, and what I have contributed to this area of research. I begin with a little background on QCD, and Chiral theories. I analyze Kaon Nucleon scattering, and calculate the Kaon Nucleon scattering length from data obtained using a lattice QCD simulation. Therefore, I show that it is possible to use Lattice QCD simulation to extract observables. This is important in areas where experiments are challenging or impossible with current technologies.