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New Developments In Planning Accelerated Life Tests, Haiming Ma Jan 2009

New Developments In Planning Accelerated Life Tests, Haiming Ma

Graduate Theses and Dissertations

Accelerated life tests (ALTs) are often used to make timely assessments of the life time distribution of materials and components. The goal of many ALTs is estimation of a quantile of a log-location failure time distribution. Much of the previous work on planning accelerated life tests has focused on deriving test-planning methods under a specific log-location distribution. This thesis presents a new approach for computing approximate large-sample variances of maximum likelihood estimators of a quantile of general log-location distribution with censoring and time-varying stress based on a cumulative exposure model. This thesis also presents a strategy to develop useful test ...


Laser Microfabrication And Testing Of Silicon Carbide Diaphragms For Mems Applications, Benjamin Pecholt Jan 2009

Laser Microfabrication And Testing Of Silicon Carbide Diaphragms For Mems Applications, Benjamin Pecholt

Graduate Theses and Dissertations

Laser microfabrication of silicon carbide for MEMS applications was explored. 3C-SiC and 6H-SiC were laser micromachined using various lasers. 3C-SiC thin films were patterned using an 800 nm 120fs Ti:Sapphire laser. Diaphragm structures 100-130 ym thick with lateral dimensions ranging from 1-2.5 mm were fabricated in bulk 6H-SiC using a 1064 nm, <100 ns, Q-switched Nd:YAG laser. The laser micromachined diaphragms were mechanically characterized by means of nanoindentation and a novel pressure testing apparatus. Mechanical tests indicate that the diaphragms remain sealed under applied gas pressure and that the heat effects and variations in pulse energy from the laser reduce the overall mechanical strength of the diaphragms.


Modeling And Discrimination For Spectral-Temporal Data, Monica Marie Reising Jan 2009

Modeling And Discrimination For Spectral-Temporal Data, Monica Marie Reising

Graduate Theses and Dissertations

This thesis focuses on applying statistical methods to spectral-temporal data obtained from point source events. This work arises from the need in some military and national defense applications to quickly detect, locate, and identify short duration "energetic" electromagnetic events providing particular characteristic patterns of evolution over time. The first article discusses model building for spectral-temporal data that have complete spectral and temporal information over an event's evolution. The goal of this work was to build models to serve as the basis for algorithms that can be used to distinguish between different types of electromagnetic events in real time.

The ...


In-Utero Exposure To Alcohol And Nicotine Alters The Fetal Lung Innate Immunity And Development, Tatjana Lazic Jan 2009

In-Utero Exposure To Alcohol And Nicotine Alters The Fetal Lung Innate Immunity And Development, Tatjana Lazic

Graduate Theses and Dissertations

Despite the evidence that alcohol and cigarette smoke have harmful effects on the developing fetus, alcohol consumption and smoking during pregnancy remains a common behavior among women. Fetal exposure to alcohol can result in numerous developmental abnormalities referred to as fetal alcohol spectrum disorder (FASD). Fetal exposure to cigarette smoke is related to premature birth and low birth weight for gestational age. Recent evidence suggests, however, that both alcohol and cigarette smoke may alter the fetal lung development and immunity and therefore predispose infants to respiratory infections. The purpose of this study was to establish new, advantageous animal models for ...


Two Impacts Of Wind Penetration: Transient Frequency Response And Load Following Requirements, Shuyang Zhang Jan 2009

Two Impacts Of Wind Penetration: Transient Frequency Response And Load Following Requirements, Shuyang Zhang

Graduate Theses and Dissertations

Wind power installation in U.S. has increased tremendously in 2007, twice as much as the increase in 2006. With more and more wind power being integrated into power systems, it is important to investigate the wind integration effect with respect to increasing wind penetration levels. In the past few years lots much research has been performed in this area.

In this study, two parallel approaches, transient simulation and statistical analysis, are used to study the influence of increasing wind power penetration levels within a power system. Both of these methods support identification of the maximum wind penetration level in ...


Leading Them To Water: A Study Of The Efficacy Of A Mandatory Placement Project In First-Year Academic Courses At A Community College, Janet Elizabeth Emmerson Jan 2009

Leading Them To Water: A Study Of The Efficacy Of A Mandatory Placement Project In First-Year Academic Courses At A Community College, Janet Elizabeth Emmerson

Graduate Theses and Dissertations

Student retention is a topic at the forefront for all post secondary education institutions. Supporting students in their studies, providing the resources to empower them to complete their education is a critical component in the quality and success of colleges. It is also a fiscal concern for colleges. While first year programs abound, community colleges are faced with the challenges of a largely commuter population with very diverse backgrounds. Community colleges are also by mission, open access institutions.

This quantitative research study looked at a mandatory placement project piloted at a central Iowa community college in 2006 and 2007. It ...


Synthesis, Characterization, And Application Of Surface-Functionalized Ordered Mesoporous Nanoparticles, Po-Wen Chung Jan 2009

Synthesis, Characterization, And Application Of Surface-Functionalized Ordered Mesoporous Nanoparticles, Po-Wen Chung

Graduate Theses and Dissertations

The monodispersed spherical MSN with different mesoporous structure (MCM 48) was developed and employed as a template for the synthesis of mesoporous carbon nanoparticles (MCN) via nanocasting. MCN was demonstrated for the delivery of membrane impermeable chemical agents inside the cells. The cellular uptake efficiency and biocompabtibility of MCN with human cervical cancer cells were also investigated. In addition to the biocompabtibility of MCN, MCN was demonstrated to support Rh-Mn nanoparticles for catalytic reaction. Owing to the unique mesoporosity, Rh-Mn nanoparticles can be well distributed inside the mesoporous structure and exhibited interesting catalytic performance on CO hydrogenation. In addition, the ...


Synthesis Of Heteroaromatic Natural Products, Haitao Guo Jan 2009

Synthesis Of Heteroaromatic Natural Products, Haitao Guo

Graduate Theses and Dissertations

The synthesis of biologically active natural products has been used for the discovery of new drugs. Organic synthesis is designed for a target molecule like a novel compound by selecting optimal reactions from optimal starting materials. Each reaction and each step of a synthesis should give a good yield for the product with little work.

In this thesis, we explored both total synthesis and methodology of several natural products and analogs, especially heteroaromatic natural compounds. Chapter 1 describes an efficient synthesis of 2-substituted and 2,3-disubstituted indoles via a two-step approach in one pot involving a six-electron ring closure. Chapter ...


Affective Responses To Physical Activity In Obese Women: A High-Intensity Interval Bout Vs. A Longer Isocaloric Moderate-Intensity Bout, Emily Sue Decker Jan 2009

Affective Responses To Physical Activity In Obese Women: A High-Intensity Interval Bout Vs. A Longer Isocaloric Moderate-Intensity Bout, Emily Sue Decker

Graduate Theses and Dissertations

BACKGROUND: As the prevalence of obesity and inactivity continue to increase worldwide, the need for effective intervention strategies remains. Despite the well-known benefits of leading a physically active lifestyle, of those individuals classified as obese, only 3.0% of the women and 6.4% of the men trying to lose weight actually meet the 60 min/day physical activity guidelines for weight management (Bish et al., 2005). With lack of time being one of the most oft-cited reasons for not being active (King et al., 2000), the use of short-duration, high-intensity interval training (HIT) has been suggested as a time-efficient ...


Questions About Accountability And Illegality Of Virtual Rape, Melissa Mary Fenech Sander Jan 2009

Questions About Accountability And Illegality Of Virtual Rape, Melissa Mary Fenech Sander

Graduate Theses and Dissertations

Virtual rape is not a new phenomenon in virtual communities, as Julian Dibbell’s 1993 article pointed out, but it is beginning to gain attention in some scholarly circles. Of the articles specifically covering virtual rape, most focus on whether or not virtual rape is “real” while some attempt to isolate its social construction. Only one scholar to date has argued the legality of the offense, but limited the discussion only to consensual virtual rape. With this in mind, this thesis is focused on defining non–consensual virtual rape, comparing and contrasting it to other types of online deviance such ...


Are They Satisfied?: A Study Of Urban Secondary Family And Consumer Sciences Teachers, Maureen Lynea Tucker Jan 2009

Are They Satisfied?: A Study Of Urban Secondary Family And Consumer Sciences Teachers, Maureen Lynea Tucker

Graduate Theses and Dissertations

This study investigated the overall job satisfaction of urban family and consumer sciences teachers in Texas using a quantitative approach. The Minnesota Satisfaction Questionnaire (short form) was used via a web-based survey through Iowa State University. The review of literature yielded an alarming deficit in satisfaction studies of family and consumer sciences teachers.

The data analysis indicated urban FCS teachers in Texas were neither satisfied nor dissatisfied with their overall level of job satisfaction. Their intrinsic job satisfaction (i.e. security, variety, independence, recognition, moral values, social service, authority, abilities and creativity) was higher, yielding a satisfactory level. Extrinsic job ...


A Study Of The Status And Social Acclimation Of International Students' Wives At Iowa State University And Ames Community, Julia Mitrushi Jan 2009

A Study Of The Status And Social Acclimation Of International Students' Wives At Iowa State University And Ames Community, Julia Mitrushi

Graduate Theses and Dissertations

This qualitative study explores the characteristics, needs, and expectations of the international students' wives in Ames, Iowa. Participants included 89 international students' wives from twenty different countries. International students' wives enter the United States on a dependent visa status, and they experience a unique set of challenges while accompanying their husbands.

The purpose of this study was to gain some insights on how international students' wives perceive their internal and external resources at arrival, and the types of obstacles they have to overcome to achieve a successful adaptation to this transitional role. It also tested additional exploratory questions related to ...


Is Corruption Endogenous To Foreign Direct Investment In Resource-Rich Developing Economies?, Saw Htay Wah Jan 2009

Is Corruption Endogenous To Foreign Direct Investment In Resource-Rich Developing Economies?, Saw Htay Wah

Graduate Theses and Dissertations

This paper offers econometric evidence that corruption and foreign direct investment (FDI) can co-evolve if conditional on the level of development, the type of regimes, and the level of natural resource endowment. In conventional FDI empirical studies, the perceived corruption level in host countries is treated as being exogenous. Corruption, however, is also found to be endogenous to FDI depending upon economic circumstances and political conditions prevailing in host countries. The impact of FDI on corruption in host economies is found to vary across economies if disaggregated samples are used. Asian economies show a different pattern as compared to other ...


An Economic Analysis Of Decisions On Physical Activity And Energy Imbalance: Cross-Sectional Evidence From A Panel Of Middle-Aged Adults, Yanni Chen Jan 2009

An Economic Analysis Of Decisions On Physical Activity And Energy Imbalance: Cross-Sectional Evidence From A Panel Of Middle-Aged Adults, Yanni Chen

Graduate Theses and Dissertations

Ample evidence indicates that regular physical activity has many human health benefits. Maintenance of good physical fitness enables one to meet the physical demands of work and leisure comfortably and be less prone to a number of illnesses. In addition to physical inactivity, a poor diet is another factor in energy imbalance (more calories consumed than expended). According to the Dietary Guidelines for Americans 2005, physical inactivity and poor diets are the two most important factors contributing to the increase in overweight and obesity in the United States. Overweight and obesity are major risk factors for certain chronic diseases such ...


Attitudes Of General Education Teachers Toward Including Students With Special Needs, Tracy Lynn Cagney Jan 2009

Attitudes Of General Education Teachers Toward Including Students With Special Needs, Tracy Lynn Cagney

Graduate Theses and Dissertations

Due to the recent push towards inclusion, many students with special needs are finding themselves in the general education classroom. Research has shown that students' success in classes is affected by their teachers' attitudes towards having them in there. This study takes a closer look at high school general education teachers' attitudes, in the state of Iowa, towards working with students with special needs in the general education classroom.


Split, Darci Catorci Kellen Jan 2009

Split, Darci Catorci Kellen

Graduate Theses and Dissertations

April is a fourteen-year-old dealing with a split life. She tries to make sense of her sister's death, and what kind of girl she is while being shipped back and forth between her extreme parents. She starts an environmental club with friends in an atempt to make a difference, but even that gets split when Skye, a new boy from Cali, decides to start his own green group.


Algorithms For Efficient Phylogenetic Tree Construction, Mukul Subodh Bansal Jan 2009

Algorithms For Efficient Phylogenetic Tree Construction, Mukul Subodh Bansal

Graduate Theses and Dissertations

The rapidly increasing amount of available genomic sequence data provides an abundance of potential information for phylogenetic analyses. Many models and methods have been developed to build evolutionary trees based on this information. A common feature of most of these models is that they start out with fragments of the genome, called genes. Depending on the genes and species, and the methods used to perform the phylogenetic analyses, one typically ends up with a large number of phylogenetic trees which may not agree with one another. Simply put, the problem now is the following: Given several discordant phylogenetic trees as ...


Ionic Liquids: Maldi-Ms Matrices And Gas Chromatography Stationary Phases, Jeffrey Aaron Crank Jan 2009

Ionic Liquids: Maldi-Ms Matrices And Gas Chromatography Stationary Phases, Jeffrey Aaron Crank

Graduate Theses and Dissertations

This thesis shows the systematic variation of both the cation and anion to find an ionic liquid matrix that produces the greatest analyte S/N ratio. It is also demonstrated that these new ILMs have a greater mass detection range and can be used for a wider variety of analytes. Analytes tested include peptides, proteins, and carbohydrates.

Also reported is the characterization of sixteen biodegradable polymers with two ILMs and five solid matrices. It is shown that the ILM produces less degradation and typically allows detection of an almost Gaussian distribution of analyte peaks. This allows detection of a more ...


The Culture Differences On Web Design: A Study Of Taiwan's And United States' Websites, Wan-Ting Tsai Jan 2009

The Culture Differences On Web Design: A Study Of Taiwan's And United States' Websites, Wan-Ting Tsai

Graduate Theses and Dissertations

The internet is a global phenomenon that human transmits information almost simultaneously. Thus websites have become a critical communication media not only for international business but also for society. Even though websites are globally accessible, users from different cultures may have different preferences and perceptions. By using Taiwan as a case to study for culture and web design, this thesis aims to find the design characteristics of Taiwan's websites that are uniquely Taiwanese. It will also examine how cultural differences influences web design by comparing Taiwan's websites and those of United States' will be used to study according ...


Some Theoretical Contributions To The Evaluation And Assessment Of Finite Mixture Models With Applications, Volodymyr Melnykov Jan 2009

Some Theoretical Contributions To The Evaluation And Assessment Of Finite Mixture Models With Applications, Volodymyr Melnykov

Graduate Theses and Dissertations

This dissertation develops theory and methodology for the evaluation and assessment of finite mixture models. New methods for simulating finite mixture models satisfying a pre-specified level of complexity defined through the notion of pairwise overlap, are developed. Corresponding software is publicly available at CRAN. This dissertation also develops methodology for assessing significance in finite mixture models with applications to model-based unsupervised and semi-supervised clustering frameworks. The dissertation concludes with an application of finite mixture models to two-dimensional gel electrophoresis.


The Mechanisms And Roles Of Quorum Sensing In The Pathobiology Of Campylobacter Jejuni, Paul Joseph Plummer Jan 2009

The Mechanisms And Roles Of Quorum Sensing In The Pathobiology Of Campylobacter Jejuni, Paul Joseph Plummer

Graduate Theses and Dissertations

Campylobacter jejuni is the leading cause of food borne bacterial enteritis in the United States, as well as around the world, and is commonly contracted after consuming contaminated meat (especially poultry), unpasteurized milk, or contaminated drinking water. Since the ability of this bacterial species to respond to changes in the extracellular environment is paramount to its ability to cause disease, the mechanisms responsible for adaptation provide a viable target for bacterial control. The autoinducer-2 (AI-2) mediated quorum sensing system is widely conserved over both gram negative and gram positive bacteria and has been demonstrated to play a critical role in ...


Considering Value Of Information When Using Cfd In Design, John Satprim Misra Jan 2009

Considering Value Of Information When Using Cfd In Design, John Satprim Misra

Graduate Theses and Dissertations

This thesis presents an approach to find lower resolution CFD models that can accurately lead a designer to a correct decision at a lower computational cost. High-fidelity CFD models often contain too much information and come at a higher computational cost, limiting the designs a designer can test and how much optimization can be performed on the design. Lower model resolution is commonly used to reduce computational time. However there are no clear guidelines on how much model accuracy is required. Instead experience and intuition are used to select an appropriate lower resolution model. This thesis presents an alternative to ...


Asynchronous Stigmergic Sorting Of Binary Matrix Patterns: Applications Of Classical Distributed Computing Ideas, Neeraj S. Khanolkar Jan 2009

Asynchronous Stigmergic Sorting Of Binary Matrix Patterns: Applications Of Classical Distributed Computing Ideas, Neeraj S. Khanolkar

Graduate Theses and Dissertations

Multi-agent stigmergy forms the basis of explanatory theories for various self-organized biological phenomena, and also serves as an implementation strategy for several important artificial applications. While a number of sophisticated techniques have been used in the modeling and analysis of stigmergic processes, none of them, yet, seem to be drawn from the toolbox of classical distributed computing. Our goals are to investigate and lay the groundwork for the use of classical distributed computing ideas in reasoning about stigmergic computation.

Specifically, we investigate case studies that are drawn from the domain of binary matrix pattern sorting. Here, a `swarm' of memory-less ...


Using A Seed-Network To Query Multiple Large-Scale Gene Expression Datasets From The Developing Retina In Order To Identify And Prioritize Experimental Targets, Timothy Alcon Jan 2009

Using A Seed-Network To Query Multiple Large-Scale Gene Expression Datasets From The Developing Retina In Order To Identify And Prioritize Experimental Targets, Timothy Alcon

Graduate Theses and Dissertations

Understanding the gene networks that orchestrate the differentiation of retinal progenitors into photoreceptors in the developing retina is important not only due to its therapeutic applications in treating retinal degeneration but also because the developing retina provides an excellent model for studying CNS development. Although several studies have profiled changes in gene expression during normal retinal development, these studies offer at best only a starting point for functional studies focused on a smaller subset of genes. The large number of genes profiled at comparatively few time points makes it extremely difficult to reliably infer gene networks from a gene expression ...


Porcine Reproductive And Respiratory Syndrome Virus (Prrsv): Immunization Strategies, Virulence Of Various Isolates, And Efficacy Of Dna Vaccination, Wesley Scott Johnson Jan 2009

Porcine Reproductive And Respiratory Syndrome Virus (Prrsv): Immunization Strategies, Virulence Of Various Isolates, And Efficacy Of Dna Vaccination, Wesley Scott Johnson

Graduate Theses and Dissertations

Many different strategies have been pursued by researchers in the quest for control and ultimately the eradication of porcine reproductive and respiratory syndrome (PRRS). Some of the strategies have lead to the licensure of commercial products while others have provided insight into the biology of porcine reproductive and respiratory syndrome virus (PRRSV). Many of the strategies examined here have contributed to the overall understanding of the host's immune response to PRRSV. Some strategies have provided unconventional or in some cases controversial methods of protecting swine from PRRS. The main area of interest in this review will be the clinical ...


Development Of A System For Characterizing Biomass Quality Of Lignocellulosic Feedstocks For Biochemical Conversion, Patrick Thomas Murphy Jan 2009

Development Of A System For Characterizing Biomass Quality Of Lignocellulosic Feedstocks For Biochemical Conversion, Patrick Thomas Murphy

Graduate Theses and Dissertations

The purpose of this research was twofold: (i) to develop a system for screening lignocellulosic biomass feedstocks for biochemical conversion to biofuels and (ii) to evaluate brown midrib corn stover as feedstock for ethanol production.

In the first study (Chapter 2), we investigated the potential of corn stover from bm1-4 hybrids for increased ethanol production and reduced pretreatment intensity compared to corn stover from the isogenic normal hybrid. Corn stover from hybrid W64A X A619 and respective isogenic bm hybrids was pretreated by aqueous ammonia steeping using ammonium hydroxide concentrations from 0 to 30%, by weight, and the resulting residues ...


Jurassic And Cretaceous Tectonic Evolution Of The Southeast Castle Dome Mountains, Southwest Arizona, Jonathan Hunter Reis Jan 2009

Jurassic And Cretaceous Tectonic Evolution Of The Southeast Castle Dome Mountains, Southwest Arizona, Jonathan Hunter Reis

Graduate Theses and Dissertations

The southeast Castle Dome Mountains of southwest Arizona record the Mesozoic to Cenozoic geologic evolution of the Southwest. The age and tectonic setting of the informally named metasedimentary and metavolcanic rocks of Slumgullion have occasioned considerable debate, although some previous researchers have postulated a Jurassic age. Possible correlatives to the rocks of Slumgullion include the McCoy Mountains Formation of southeast California and southwest Arizona and the Winterhaven Formation of southeast California.

Within the rocks of Slumgullion detrital zircon ages were obtained from various metasedimentary units, including quartz arenites, arkosic sandstones, and a lithic arenite, in order to place constraints on ...


Genetic Profile And Horticultural Evaluation Of Styrax Americanus (American Snowbell), Olivia Marie Lenahan Jan 2009

Genetic Profile And Horticultural Evaluation Of Styrax Americanus (American Snowbell), Olivia Marie Lenahan

Graduate Theses and Dissertations

Styrax americanus Lam. (American snowbell) is an ornamental tree or shrub seldom used in the nursery industry. The species is common in the southeastern United States and is distributed continuously as far north as southeastern Virginia and southern Illinois. We studied a small, threatened population in northern Illinois (latitude = 41y10N), about 500 km disjunct from populations to the south. Little is known about the genetic diversity and landscape potential of this species. The first objective was to evaluate the genetic structure of the northern disjunct population and compare those individuals genetically to populations from the northern and southern extremes of ...


Experimental Observations And Simulations Of The Mechanical Deformation Of Amorphous Metallic Foam, Sarah Shiley Haubrich Jan 2009

Experimental Observations And Simulations Of The Mechanical Deformation Of Amorphous Metallic Foam, Sarah Shiley Haubrich

Graduate Theses and Dissertations

In this study, the deformation mechanisms of bulk metallic glass (BMG) foam with around 49% porosity were investigated by using X-Ray Computed Tomography (CT) technique. X-Ray CT experiments were conducted at ESRF Synchrotron Source, Grenoble, France where the in-situ compression testing is possible. The collected CT images were digitally enhanced and the volumetric strain of the foam cells was calculated. The visual analysis of the foam cells was compared with a finite element model to determine whether the foam exhibited any pressure sensitivity.

The sample experiences uniform local deformation under compression until a few geometric instabilities in the foam induce ...


Measurement Of Pvfs2 Performance On Infiniband, Sudhindra Prasad Tirupati Nagaraj Jan 2009

Measurement Of Pvfs2 Performance On Infiniband, Sudhindra Prasad Tirupati Nagaraj

Graduate Theses and Dissertations

InfiniBand is becoming increasingly popular as a fast interconnect technology between servers and storage. It has far better price/performance ratio compared to both Gigabit Ethernet and 10 Gigabit Ethernet, and hence is being increasingly used for high-performance computing applications. PVFS2, the second generation Parallel Virtual File System (PVFS), is a distributed file system for parallel data access that is being increasingly used in clustered applications. As previous studies have shown that in general, PVFS2 over InfiniBand offers enhanced I/O rates compared to PVFS2 over TCP and Gigabit Ethernet. Apart from the hardware technology, the application programming interface into ...