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Accelerated Life Testing Of Subsea Equipment Under Hydrostatic Pressure, Amar Raja Thiraviam

Electronic Theses and Dissertations

Accelerated Life Testing (ALT) is an effective method of demonstrating and improving product reliability in applications where the products are expected to perform for a long period of time. ALT accelerates a given failure mode by testing at amplified stress level(s) in excess of operational limits. Statistical analysis (parameter estimation) is then performed on the data, based on an acceleration model to make life predictions at use level. The acceleration model thus forms the basis of accelerated life testing methodology. Well established accelerated models such as the Arrhenius model and the Inverse Power Law (IPL) model exist for key stresses …

Structural Health Monitoring Of A Stadium For Evaluating Human Comfort And Structural Performance, Hasan Sazak

Electronic Theses and Dissertations

Light and rapid constructions as well as considerations such as improved line of sight and increased capacity for modern stadium structures make them vulnerable for vibration serviceability problems. These problems are also observed at convention centers, large shopping malls, concert halls and ballrooms. Especially when the individuals in a crowd are involved in some sort of coordinated motion, this type of loading creates the most potential for high levels of vibration. In order to understand the causes of vibration, vibration levels, service and safety levels, Structural Health Monitoring (SHM) can be implemented to track and evaluate performance of a structure …

Stress Concentration Factors For V-Notched Plates Under Axisymmetric Pressure, Nathan J. Mutter

HIM 1990-2015

The topic of this thesis is the investigation of the local states of stress resulting from the introduction of av-notch in a coaxial circle on the pressurized surface of a circumferentially clamped plate subject to axisymmetric loading. The understanding of the fracture behavior of a component experiencing such a condition is of particular interest to the aerospace and defense industries where circular plate components are often utilized. In such applications, it is imperative that the designer be able to predict the loading conditions facilitating dynamic fracture. As a step towards solving such problems, the quasi-static analogy is studied. Specifically, the …

Development Of An Improved Microwave Ocean Surface Emissivity Radiative Transfer Model, Salem El-Nimri

Electronic Theses and Dissertations

An electromagnetic model is developed for predicting the microwave blackbody emission from the ocean surface over a wide range of frequencies, incidence angles, and wind vector (speed and direction) for both horizontal and vertical polarizations. This ocean surface emissivity model is intended to be incorporated into an oceanic radiative transfer model to be used for microwave radiometric applications including geophysical retrievals over oceans. The model development is based on a collection of published ocean emissivity measurements obtained from satellites, aircraft, field experiments, and laboratory measurements. This dissertation presents the details of methods used in the ocean surface emissivity model development …

Mitigating Misbehavior In Wireless Networks: A Game Theoretic Approach, Wenjing Wang

Electronic Theses and Dissertations

In a distributed wireless system, multiple network nodes behave cooperatively towards a common goal. Though such assumptions on cooperation are desirable (e.g., controlling the transmit power level, reducing interference for each other, revealing private information, adhering to network policies) for analyzing and modeling, certain nodes belonging to a real-world system have often shown to deviate. These nodes, known as misbehaving nodes, bring more challenges to the design of the wireless network because the unreliable channel makes the actions of the nodes hidden from each other. In this dissertation, we analyze two types of misbehavior, namely, selfish noncooperation and malicious attacking. …

Architectural Support For Improving Computer Security, Jingfei Kong

Electronic Theses and Dissertations

Computer security and privacy are becoming extremely important nowadays. The task of protecting computer systems from malicious attacks and potential subsequent catastrophic losses is, however, challenged by the ever increasing complexity and size of modern hardware and software design. We propose several methods to improve computer security and privacy from architectural point of view. They provide strong protection as well as performance efficiency. In our first approach, we propose a new dynamic information flow method to protect systems from popular software attacks such as buffer overflow and format string attacks. In our second approach, we propose to deploy encryption schemes …

Real-Time Cinematic Design Of Visual Aspects In Computer-Generated Images, Juraj Obert

Electronic Theses and Dissertations

Creation of visually-pleasing images has always been one of the main goals of computer graphics. Two important components are necessary to achieve this goal --- artists who design visual aspects of an image (such as materials or lighting) and sophisticated algorithms that render the image. Traditionally, rendering has been of greater interest to researchers, while the design part has always been deemed as secondary. This has led to many inefficiencies, as artists, in order to create a stunning image, are often forced to resort to the traditional, creativity-baring, pipelines consisting of repeated rendering and parameter tweaking. Our work shifts the …

Assessment Of Aquifer Storage And Recovery Impact On Phosphorus Stability In Lake Sediment, Sha Liu

Electronic Theses and Dissertations

Lake Okeechobee, the second largest natural freshwater lake in the United States, had experienced a historical drought in 2007-2008 and the inflow to Lake Okeechobee has been reduced by 40% of the average daily mean between warm phase and cold phase due to the impact of Atlantic Multidecadal Oscillation in the past six decades. To cope with this water resources management problem, the US Army Corps of Engineers (USACE) proposed the largest national implementation plan of aquifer storage and recovery (ASR) project in the Kissimmee River Basin. Routine operation of ASR will deliver recovered water from ASR wells into the …

Establishing Degradation Rates And Service Lifetime Of Photovoltaic Systems, Albert Leyte-Vidal

Electronic Theses and Dissertations

As fossil fuel sources continue to diminish, oil prices continue to increase, and global warming and CO2 emissions keep impacting the environment, it has been necessary to shift energy consumption and generation to a different path. Solar energy has proven to be one of the most promising sources of renewable energy because it is environmentally friendly, available anywhere in the world, and cost competitive. For photovoltaic (PV) system engineers, designing a PV system is not an easy task. Research demonstrates that different PV technologies behave differently under certain conditions; therefore energy production varies not only with capacity of the system …

Microstructural Investigation Of Precipitation Hardened Cuni2s+Zr Alloys For Rotor Applications, Jean-Paul Vega-Garcia

Electronic Theses and Dissertations

Industrial generator components experience high stresses and electrical fields during their service life. Material integrity is key in guaranteeing component performance. CuNi2SiZr, used as rotor wedges in generators, serve to maintain rotor slot content in place while experiencing high centrifugal stresses and low cycle fatigue during start and stop at elevated temperature. The quality and integrity of this material in service can be directly related to its microstructure, which is determined by the processing procedures of the wedges. In this study, the microstructure development in this material is evaluated to eliminate grain boundary defects by optimizing processing parameters, determining the …

A New Development Of Feedback Controller For Left Ventricular Assist Device, Yu Wang

Electronic Theses and Dissertations

The rotary Left Ventricular Assist Device (LVAD) is a mechanical pump surgically implanted in patients with end-stage congestive heart failure to help maintain the flow of blood from the sick heart. The rotary type pumps are controlled by varying the impeller speed to control the amount of blood flowing through the LVAD. One important challenge in using these devices is to prevent the occurrence of excessive pumping of blood from the left ventricle (known as suction) that may cause it to collapse due to the high pump speed. The development of a proper feedback controller for the pump speed is …

A Study Of The Strength Of Pervious Pavement Systems, Ikenna Uju

Electronic Theses and Dissertations

This thesis presents a study on the strength properties of the different pervious pavement systems installed at the Stormwater Management Academy field laboratory at University of Central Florida (UCF), Orlando. The strength tests were performed both in the laboratory and in the field. Laboratory testing was conducted to determine the compressive strength and flexural strength of the various pavement surfaces. Evaluation of field pavement performance was performed by comparing the deflection basins using the Falling Weight Deflectometer test on pervious concrete and porous asphalt with conventional impervious concrete and asphalt pavements of similar layer profile and thickness, respectively. From literature …

A New Framework For Qos Provisioning In Wireless Lans Using The P-Persistent Mac Protocol, Kiran Babu Anna

Electronic Theses and Dissertations

The support of multimedia traffic over IEEE 802.11 wireless local area networks (WLANs) has recently received considerable attention. This dissertation has proposed a new framework that provides efficient channel access, service differentiation and statistical QoS guarantees in the enhanced distributed channel access (EDCA) protocol of IEEE 802.11e. In the first part of the dissertation, the new framework to provide QoS support in IEEE 802.11e is presented. The framework uses three independent components, namely, a core MAC layer, a scheduler, and an admission control. The core MAC layer concentrates on the channel access mechanism to improve the overall system efficiency. The …

Spatio-Temporal Maximum Average Correlation Height Templates In Action Recognition And Video Summarization, Mikel Rodriguez

Electronic Theses and Dissertations

Action recognition represents one of the most difficult problems in computer vision given that it embodies the combination of several uncertain attributes, such as the subtle variability associated with individual human behavior and the challenges that come with viewpoint variations, scale changes and different temporal extents. Nevertheless, action recognition solutions are critical in a great number of domains, such video surveillance, assisted living environments, video search, interfaces, and virtual reality. In this dissertation, we investigate template-based action recognition algorithms that can incorporate the information contained in a set of training examples, and we explore how these algorithms perform in action …

Investigation Of Thermal, Elastic And Load-Biased Transformation Strains In Niti Shape Memory Alloys, Shipeng Qiu

Electronic Theses and Dissertations

Polycrystalline NiTi shape memory alloys have the ability to recover their original, pre-deformed shape in the presence of external loads when heated through a solid-solid phase transformation from a lower-symmetry B19' martensite phase to a higher-symmetry B2 austenite phase. The strain associated with a shape memory alloy in an actuator application typically has thermal, elastic and inelastic contributions. The objective of this work was to investigate the aforementioned strains by recourse to in situ neutron diffraction experiments during selected combinations of heating, cooling and/or mechanical loading. The primary studies were conducted on polycrystalline Ni49.9Ti50.1 specimens on the Spectrometer for MAterials …

Optimized Market Introduction Of Large Capital Products (Lcp) With Long Development And Learning Cycles, Antje Lembcke

Electronic Theses and Dissertations

Any product sold is expected to be reliable and available when the customer wants to operate it. Companies that produce large capital products (LCP), such as rockets, satellites, or large gas turbines to generate electrical energy, tend to shy away from extending their testing and validation method above the requirements by law, mainly due to the very high costs of each additional test and the uncertain return on investment. This research shows that today’s state of the art validation methods for LCP, required by law, or suggested in literature, and adapted by these industries, are not capable of capturing all …

Dordt College 2010-2011 Catalog, Dordt College. Registrar's Office

Academic Catalogs

Academic Catalog for 2010-2011

Quantum Interference Experiments, Modular Variables And Weak Measurements, Jeff Tollaksen, Yakir Aharonov, Aharon Casher, Tirzah Kaufherr, Shmuel Nussinov

Mathematics, Physics, and Computer Science Faculty Articles and Research

We address the problem of interference using the Heisenberg picture and highlight some new aspects through the use of pre-selection, post-selection, weak measurements and modular variables. We present a physical explanation for the different behaviors of a single particle when the distant slit is open or closed; instead of having a quantum wave that passes through all slits, we have a localized particle with non-local interactions with the other slit(s). We introduce a Gedanken experiment to measure this non-local exchange. While the Heisenberg and Schrodinger pictures are equivalent formulations of quantum mechanics, nevertheless, the results discussed here support a new …

Frustrated Drift Of An Anchored Scroll-Wave Filament And The Geodesic Principle, Marcel Wellner, Christian W. Zemlin, Arkady M. Pertsov

Bioelectrics Publications

We investigate anchored scroll-wave filaments in an excitable medium whose diffusivity matrix, including its determinant, is spatially nonuniform. The study is motivated by cardiological applications where scroll-wave behavior in the presence of diffusivity gradients is believed to play an important role in the development of severe arrhythmias. A diffusivity gradient is expected to make the filament drift, unless drift is prevented ("frustrated") by anchoring to localized defects in the propagation medium. The resulting stationary filament is a geodesic curve, as demonstrated here in the case of a nonzero but constant gradient. That is, the diffusivity matrix has a determinant that …

A History Of El Paso's Company E In World War Ii, Jorge Rodriguez

Open Access Theses & Dissertations

For the most part, Hispanics in the U.S. military were not segregated into separate units, but there was, at least, one known exception. It is this particular story of a National Guard unit from El Paso, Texas designated as Company E that has received minimal attention by historians. This unit was unlike any other unit of the National Guard in that it consisted only of Mexican-Americans.

Synthesis And Characterization Of Ruthenium Complexes Containing Chlorophenanthroline And Bipyridine, Anwar A. Bhuiyan, S. Kudo, J. Bartlett

Journal of the Arkansas Academy of Science

The divalent ruthenium polypyridine complexes hold promise as efficient photocatalysts for solar energy conversion schemes. This paper deals with the synthesis and spectroscopic investigation of ruthenium polypyridine complexes, which may be useful as photosensitizers. The homoleptic ruthenium(II) complex Ru(Cl-phen)3(PF6)2 (where Cl-phen = 5- chloro-1,10-phenanthroline), and heteroleptic ruthenium(II) complexes Ru(Cl-phen)2(bpy)(PF6)2, and Ru(Cl-phen)(bpy)2(PF6)2 (where bpy = 2,2′-bipyridine) have been prepared by following the standard synthetic procedure. Silica and alumina column chromatographies were used to purify the compounds. Mass spectroscopy, nuclear magnetic resonance (nmr) spectroscopy, and elemental analysis were used to confirm the identity and the integrity of the complexes. Absorption and emission …

Ergodic And Combinatorial Proofs Of Van Der Waerden's Theorem, Matthew Samuel Rothlisberger

CMC Senior Theses

Followed two different proofs of van der Waerden's theorem. Found that the two proofs yield important information about arithmetic progressions and the theorem. van der Waerden's theorem explains the occurrence of arithmetic progressions which can be used to explain such things as the Bible Code.

Some Professionals Play Minimax: A Reexamination Of The Minimax Theory In Major League Baseball, Jeffrey Park

CMC Senior Theses

This paper explores the behavior of Major League Baseball pitchers. We analyze the pitching data from 2007-2010 in order to determine whether their actions follow minimax play. We also examine what the OPS statistic tells us about a pitcher's value.

A State Level Analysis Of Teach For America's Impact On Student Achievement, Steven Ferguson

CMC Senior Theses

Teach For America (TFA) has seen its profile and list of donors expand tremendously in recent years. Despite its success in attracting support, research on the effectiveness of the program has been inconclusive. This study investigates the impact of TFA on student achievement measured at the state level. Panel data from grades 4 and 8 are analyzed to examine how the presence of TFA corps members in a state impacts student test scores compared to states which have no TFA corps members.

How Are Inflation Expectations Formed By Consumers, Economists And The Financial Market?, Shaun Khubchandani

CMC Senior Theses

Inflation expectations have been of great interest to economists because they predict how agents in an economy set prices and react to changes in various macroeconomic variables. The existence of Keynesian liquidity traps in Japan and the United States have helped emphasize the importance of inflation expectations, especially when monetary policy is rendered ineffective and there is almost perfect substitutability between money and bonds due to the zero bound condition of interest rates. Given the canonical theories of rational and adaptive expectations, this paper will use a simple model of the economy to measure the effect of various macroeconomic variables …

Sustaining Rural Economies With Wind Development, Eric J. Van Oss

CMC Senior Theses

This paper discusses the effects of wind development in rural areas. Areas of focus include: direct job creation, indirect job creation, tax revenue and government policies. The effects of state and federal renewable energy policies are discussed and well as the impacts to rural economies.

Inequities Of Contemporary French Women, Olivia Kuhlman

CMC Senior Theses

This thesis is an analysis of the current situation of women in contemporary France. It analyzes the current situation of French women in education, the work force, politics, and French society, with the intent of uncovering the gender inequalities French women encounter in contemporary France.

Multicultural Education: What Is It And Does It Have Benefits?, Celestial J. Zaldana

CMC Senior Theses

The purpose of this paper was to examine multicultural education, and clarify misconceptions about it. Particularly, those misconceptions that have resulted in House Bill 2281 ( i.e. multicultural education “promotes the overthrow of the United States government”), and the misconception that multicultural education solely involves content integration. In addition, this paper examines the possible benefits of having a multicultural education. These benefits include combating the negative effects of acculturation and assimilation, reducing prejudice and the effects of stereotypes, enhancing other-group orientation, and promoting critical analysis and empowerment.

Integrated Overview, Case-Studies And Analysis: Income Inequality In Latin America, Post-1980, Aaron R. Campbell

CMC Senior Theses

This thesis provides an integrated overview on the historical and contemporary literature dedicated to the study of within-country income inequality in Latin America.

The central hypothesis of this report is that there are underlying factors that drive the persistent levels of high within-country inequality experienced by Latin American countries. We study two countries, Brazil and Bolivia, through the process of reform and growth, and note the effects on the labor markets.

Using all available statistics and the wealth of knowledge compiled since the early 1980s, this study identifies those trends, and the factors that cause them to reappear in numerous …

Improving The Instruction And Learning Of Topographic Maps Through The Use Of Geospatial Technologies, Troy Dean Schwemm

Dissertations and Theses @ UNI

Geographic information technologies (GIT) are spatially based technologies that include geographic information systems (GIS), remote sensing, and global positioning systems (GPS). Though GIT has been used in society for decades, and has grown tremendously in the last 10 years as advancements in technology have become available, its inclusion into the K-12 curriculum has not kept pace. As the educational reform movement places an ever increasing amount of pressure on schools to produce technologically literate, workforce ready graduates, school districts are scrambling to find creative, innovative ways to accomplish this task. Rather than learning passively, GIT allows students to construct their …