Digital Commons Network^™

Structural And Magnetic Characterization Study Of Hfco7 Alloy With Substitutions Of Si, Ti, Fe, Mn And B, Jacob A. Lewis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Magnetic materials are a critical component of the modern technological society. The market of high-energy product hard magnets is dominated by the rare-earth element containing neodymium-iron-boron (NdFeB) magnets. As a result of worldwide demand coupled with trade restrictions on rare-earth minerals, new magnet compositions are explored to reduce pressure on the already strained market. The hafnium-cobalt alloy system has shown promise as a candidate for filling the gap in saturation magnetization between rare-earth containing alloys and those made with abundant elements. This study explores the magnetic effects of silicon, titanium, iron, manganese and boron substitutions in the hafnium-cobalt-7 (1:7 atomic …

Experimental Study On The Effect Of Air Flow On Soap Bubble Formation, John M. Davidson

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Soap bubbles are a common interfacial fluid dynamics phenomenon having applications such as buoyant hollow spherical fillers and flow visualization of large scale airflows. In contrast to the dynamics of liquid drops in gas and gas bubbles in liquid, the dynamics of soap bubbles has not been well documented, possibly because soap bubbles have gas-liquid-gas interfaces. Having the thin-liquid-film interface seems to alter the characteristics of the bubble/drop creation process. Thus, the main objective of this study is to experimentally examine how airflow develops and interacts with the soap liquid film as the film stretches and finally collapses to pinch-off. …

Permaculture, Roslynn Brain, Blake Thomas

Environment and Society Faculty Publications

No abstract provided.

The Costs Of Ambient Cultural Disharmony: Indirect Intercultural Conflicts In Social Environment Undermine Creativity, Roy Y. J. Chua

Research Collection Lee Kong Chian School Of Business

Intercultural tensions and conflicts are inevitable in the global workplace. This paper introduces the concept of ambient cultural disharmony—indirect experience of intercultural tensions and conflicts in individuals' immediate social environment—and demonstrates how it undermines creative thinking in tasks that draw on knowledge from multiple cultures. Three studies (a network survey and two experiments) found that ambient cultural disharmony decreases individuals' effectiveness at connecting ideas from disparate cultures. Beliefs that ideas from different cultures are incompatible mediate the relationship between ambient cultural disharmony and creativity. Alternative mechanisms such as negative affect and cognitive disruption were not viable mediators. Although ambient cultural …

Financial Reporting Quality Of Chinese Reverse Merger Firms: The Reverse Merger Effect Or The China Effect?, Kun-Chih Chen, Qiang Cheng, Ying Chou Lin, Yu-Chen Lin, Xing Xiao

Research Collection School Of Accountancy

In this paper, we examine why Chinese reverse merger (RM) firms have lower financial reporting quality. We find that while U.S. RM firms have similar financial reporting quality as matched U.S. IPO firms, Chinese RM firms exhibit lower financial reporting quality than Chinese ADR firms. We further find that Chinese RM firms exhibit lower financial reporting quality than U.S. RM firms. These results indicate that the use of RM process is associated with poor financial reporting quality only in firms from China, where the legal enforcement is weaker than U.S. In addition, we find that compared to Chinese ADR firms, …

Institutional Presence, Johan Sulaeman, Chi Shen Wei

Research Collection Lee Kong Chian School Of Business

We propose an Institutional Presence (IP) measure to capture the latent role of non-owner institutional investors who nevertheless may be observing a firm. We employ this measure to examine whether the ‘presence’ of institutional investors reduces information asymmetry in the market. Firms in areas with high institutional presence experience higher liquidity, faster information incorporation, lower costs of equity capital, and less financing frictions relative to firms in low IP areas. The results hold after controlling for firm and geographical characteristics including institutional ownership and urban locality. Our findings indicate that being in the presence of institutional investors brings tangible benefits.

What Are Analysts Really Good At?, Rong Wang, Leonardo Madureira, Rong Wang, Tzachi Zach

Research Collection Lee Kong Chian School Of Business

Sell-side analysts employ different benchmarks when defining their stock recommendations. For example, a ‘buy’ for some brokers means the stock is expected to outperform its peers in the same sector (“industry benchmarkers”), while for other brokers it means the stock is expected to outperform the market (“market benchmarkers”), or just some absolute return (“total benchmarkers”). We use these benchmarks to analyze the role of stock picking, industry picking and market timing in contributing to the performance of stock recommendations. We are able to do so given that different benchmarks suggest the use of different sets of abilities. Analysis of the …

Social Media Hype In Times Of Crises: Nature, Characteristics And Impact On Organizations, Augustine Pang

Research Collection Lee Kong Chian School Of Business

This article extends Vasterman’s (2005) concept of media hype by analyzing how it applies in the social media context. It then develops the concept of social media hype, its nature, characteristics through examination of five cases that attracted much social media attention. Social media hype can be defined as a netizen-generated hype that causes huge interest that is triggered by a key event and sustained by a self-reinforcing quality in its ability for users to engage in conversation. It involves a trigger event, followed by interest waves, and sustaining of the interests on different social media platforms. In response, organizations …

In Search Of The Impactful And The Interesting: Swings Of The Pendulum?, Timothy Adrian Robert Clark, Steven W. Floyd, Mike Wright

Research Collection Lee Kong Chian School Of Business

In this article we reflect on our time as editors of JMS during the period 2003-09. First we describe the context as we saw it on assuming editorship of the Journal and the actions that we took to improve the quality of scholarship published in the journal in order to set JMS on the trajectory to become a world-leading Journal. We articulate our view of what quality means in this context and observe that we eschewed the USA-Europe divide. Rather, to be publishable, all papers had to meet the highest standards relative to their epistemological assumptions. Finally, we address two …

Contrasting Perspectives On China's Rare Earths Policies: Reframing The Debate Through A Stakeholder Lens, Leslie Hayes-Labruto, Simon J.D. Schillebeeckx, Mark Workman, Nilay Shah

Research Collection Lee Kong Chian School Of Business

This article critically compares China's rare earth policy with perspectives upheld in the rest of the world (ROW). We introduce rare earth elements and their importance for energy and present how China and the ROW are framing the policy debate. We find strongly dissonant views with regards to motives for foreign direct investment, China's two-tiered pricing structure and its questionable innovation potential. Using the metaphor of "China Inc.", we compare the Chinese government to a socially responsible corporation that aims to balance the needs of its internal stakeholders with the demands from a resource-dependent world. We find that China's internal …

Integrated Soil Fertility Management: Aggregate Carbon And Nitrogen Stabilization In Differently Textured Tropical Soils, R. M. Gentile, B. Vanlauwe, J. Six

All Peer-Reviewed Publications

Soil organic matter is important to improve and sustain soil fertility in tropical agroecosystems. The combined use of organic residue and fertilizer inputs is advocated for its positive effects on short-term nutrient supply, but the effect of the integrated use on long-term stabilization of soil organic C and N is still unclear. We conducted a 1.5-y soil incubation experiment with maize (Zea mays) residue and urea fertilizer to examine the stabilization of C and N in four Sub-Saharan African soils differing in texture (sand, sandy loam, clay loam, and clay). The inputs were enriched with 13C and 15N in a …

Sowing Seeds For The Future To Honor Tigua History And Tradition: Diabetes Prevention And Management At Ysleta Del Sur Pueblo, Sean Patrick Bruna-Lewis

Anthropology ETDs

This dissertation examines type 2 diabetes management and prevention at Ysleta del Sur Pueblo, a federally recognized American Indian tribe in El Paso, Texas. Type 2 diabetes is a serious and growing concern at the Pueblo, and while the incidence is not as high as it is in other tribes in the United States, it is still much higher than the national average. Despite excellent biomedical research that shows how individuals can prevent diabetes, and countless translated diabetes prevention programs targeted to individuals and families to prevent the disease, the incidence of diabetes continues to rise. This dissertation argues that …

Patient Risk And Data Standards In Healthcare Supply Chain, Paiman Farrokhvar

Graduate Theses and Dissertations

Patient safety is one of the most important health care challenges. It is a big concern since 1 in every 10 patients around the world is affected by healthcare errors. The focus of this study is given to preventable adverse events that caused by the errors or system flaw that could have been avoided. In this study, simulation models are developed using Arena to evaluate the impact of GS1 data standards on patient risk in healthcare supply chain. The focus was given to the provider hospital supply chain operations where inventory discrepancy and performance deficiencies in recall, return, and outdate …

L1 Methods For Shrinkage And Correlation, Jie Shen

All Dissertations

This dissertation explored the idea of L1 norm in solving two statistical problems including multiple linear regression and diagnostic checking in time series. In recent years L1 shrinkage methods have become popular in linear regression as they can achieve simultaneous variable selection and parameter estimation. Their objective functions containing a least squares term and an L1 penalty term which can produce sparse solutions (Fan and Li, 2001). Least absolute shrinkage and selection operator (Lasso) was the first L1 penalized method proposed and has been widely used in practice. But the Lasso estimator has noticeable bias and is inconsistent for variable …

The Household Poverty Dimensions Infuencing Forest Dependence In Protected Area Neighboring Communities In Africa And The Mitigation Potential Of Tourism: The Case Of Volcanoes National Park, Rwanda, Ian Munanura

All Dissertations

Volcanoes National Park (VNP) in Rwanda is one of the important protected areas for conservation in the Albertine Rift ecoregion. It inhabits some of the most rare and endemic wildlife species including mountain gorillas. Despite such importance, it continues to be threatened by forest dependence practices of local residents such as, poaching for bush meat and the harvest of non-timber forest products. These practices have been attributed largely to high levels of poverty among park neighboring residents. It is believed that poor residents rely on forest resources to supplement their subsistence livelihoods. The relationship between poverty and forest dependence behavior …

Synthesis And Characterization Of Multi-Component Enrichment Polymer Layers For Chemical Sensor Applications, James Giammarco

All Dissertations

This dissertation presents the building and study of a "universal" enrichment polymer layer system (EPLS). Thin polymer films have been utilized as enrichment layers for evanescent waveguide chemical sensors. The chemical nature of the polymer provides affinity which promotes the analyte to be absorbed. Having one highly sensitive polymer layer is suitable for a single target volatile organic compound (VOC). Here, the development of multi-layered and multi-component thin polymer films has been done to allow for more diverse affinity. Several parameters were identified to make the EPLSs suitable as enrichment layers for chemical sensor devices. The evanescent sensor devices used …

Pyrene Oligomers: Their Isolation, Molecular Characterization, And Phase Behavior, David Esguerra Taborda

All Dissertations

Carbonaceous pitches can serve as attractive precursors for advanced carbon materials such as high thermal conductivity fibers or carbon-carbon composites. Yet the effects of composition and molecular structure on the bulk properties (e.g., mesophase content and melting point) of these precursors remain only partly known, mainly because of the difficulties associated with the isolation, identification, and quantification of the large (i.e., molecular weight (mol wt) > 350-400 Da) polycyclic aromatic hydrocarbon (PAH) oligomers comprising these pitches. In this study, oligomeric fractions were isolated via supercritical extraction (SCE) from two representative pitches: a petroleum pitch (M-50) produced by the thermal polymerization of …

Study On Electromagnetic Scattering Of Cylinders Buried In A Half Space With Random Rough Surfaces Of Finite/Infinite Length, Yueyang Dai

All Dissertations

Analysis of electromagnetic scattering of buried objects is a subject of great interest due to its practical importance in both military and civil applications, such as subsurface investigation and target detection. In reality, the earth is of layered structure of random rough interfaces, which leads to a greatly increased complexity of the analysis. However, it is necessary to incorporate the nature of random rough surface and the layered structure because they both have substantial impact on the scattered signature and hence affect the study of inverse scattering and detection of buried objects. In this dissertation, a Monte-Carlo multidomain pseudospectral time …

Genetic Algorithm Techniques In Climate Changepoint Problems, Shanghong Li

All Dissertations

The first part of this dissertation studies genetic algorithms as a means of estimating the number of changepoints and their locations in a climatic time series. Such methods bypass classical subsegmentation algorithms, which sometimes yield suboptimal conclusions. Minimum description length techniques are introduced. These techniques require optimizing an objective function over all possible changepoint numbers and location times. Our general objective functions allow for correlated data, reference station aspects, and/or non-normal marginal distributions, all common features of climate time series. As an exhaustive evaluation of all changepoint configurations is not possible, the optimization is accomplished via a genetic algorithm that …

Distribution, Ecology, And Trophic Relationships Of A Colonial Waterbird: The Double-Crested Cormorant, Kate Sheehan

All Dissertations

The realized distribution of an organism is dependent on the environmental characteristics of the landscape, biological interactions within the communities in which it lives, and geographic barriers to dispersal. Changes in habitat can influence landscape characteristics, and consequently, the distribution of organisms within the landscape. The Double-crested Cormorant ( Phalacrocorax auritus ) is a piscivorous waterbird implicated in human-wildlife conflicts at aquaculture facilities and natural aquatic systems where they compete for resources (fish) with anglers and commercial fishing guides. Impacts of P. auritus on aquatic systems result from their consumption of fish stocks and their contamination of water and soil …

Factors Affecting The Surface-Mediated Reduction Of Plutonium In The Presence Of Pure Mineral Phases, Amy Hixon

All Dissertations

The overall objective of the research is to investigate the mechanistic and kinetic aspects of the surface-mediated reduction of plutonium. The first chapter is a critical review of plutonium sorption to pure mineral phases. The objective is to study if and how the mechanisms by which plutonium interacts with mineral surfaces are connected to mechanisms for the surface-mediated reduction of plutonium. The main conclusion of the review is that advanced spectroscopy, microscopy, and molecular modeling are needed to fully understand not only the surface structure of pure mineral phases, but also the coordination and bonding environment of plutonium surface complexes. …

Identification Of Novel Genes Regulating Elastic Fiber Formation Through Expression Profiling Analysis Of Elastogenic Models, Erin Sproul

All Dissertations

Background: Particularly important to the mechanical performance of native arterial blood vessels is elastin, an extracellular matrix (ECM) protein deposited by VSMCs in the form of elastic fibers, arranged in concentric lamellae in the media of the vessel wall. In addition to serving as major structural elements of arterial walls, providing extensibility and elastic recoil, elastic fibers also influence vascular cell behaviors. For these reasons tissue engineers are attempting to exploit elastic fiber biology to enhance vascular graft design and patency. Therefore, developing a greater understanding of the molecular mechanisms of elastogenesis may offer opportunities to control elastogenesis in tissue …

Large Scale 3d Mapping Of Indoor Environments Using A Handheld Rgbd Camera, Brian Peasley

All Dissertations

The goal of this research is to investigate the problem of reconstructing a 3D representation of an environment, of arbitrary size, using a handheld color and depth (RGBD) sensor. The focus of this dissertation is to examine four of the underlying subproblems to this system: camera tracking, loop closure, data storage, and integration. First, a system for 3D reconstruction of large indoor planar environments with data captured from an RGBD sensor mounted on a mobile robotic platform is presented. An algorithm for constructing nearly drift-free 3D occupancy grids of large indoor environments in an online manner is also presented. This …

Predicting Surgical Flow Disruption Recovery In Cardiothoracic Operating Rooms, Gary Palmer Ii

All Dissertations

Disruptions are common occurrences in a variety of healthcare settings and early research has shown that they are likely contributors to medical errors. For this reason, healthcare researchers have focused on studying and understanding the nature of Surgical Flow Disruptions (SFDs) to increase patient safety and quality of care within the operating room (OR). Many researchers have used simplistic taxonomies to collect and categorize the types of SFD that occur within the OR. Others have gone further to study SFD recovery and have link unrecovered and recovered SFD to minor and major adverse events experienced by patients. This dissertation, focused …

Engineering Beta-Cell Spheroids For Type 1 Diabetes Treatment, Xiaoyan Liu

All Dissertations

Diabetes mellitus, the third most common disease in the world, is a chronic metabolic disorder caused by a failure of insulin production and/or an inability to respond to insulin. Specifically, type 1 diabetes is a disorder characterized by targeted autoimmune-directed destruction of a patient's beta-cell population within the pancreatic islets of Langerhans. The current primary treatment for type 1 diabetes is daily multiple insulin injections. However, this treatment cannot provide sustained physiological release, and the insulin amount is not finely tuned to glycemia. Pancreatic transplants or islet transplants would be the preferred treatment method but the lack of donor tissue …

Effect Of Graphitic Carbon Nanomodifiers On The Electromagnetic Shielding Effectiveness Of Linear Low Density Polyethylene Nanocomposites, Byron Villacorta Hernandez

All Dissertations

Conductive polymer composites have become alternative materials for providing electromagnetic and electrostatic shielding where metals are not suitable. In this study, the effect of crystallinity, morphology, concentration and orientation of carbon nanomodifiers on shielding provided by their polyethylene-based composites has been investigated relative to their transport properties.

First, the electrical properties and EM SE of composites consisting of heat-treated carbon nanofibers (Pyrograf^® -III PR-19 CNF) in a linear low density polyethylene (LLDPE) matrix were assessed. Heat treatment (HT) of CNF at 2500°C significantly improved their graphitic crystallinity and intrinsic transport properties, thereby increasing the EM SE of the nanocomposites. …

Hybrid Low-Order Modeling For Conceptual Vehicle Design, Robert Mau

All Dissertations

Design freedom, and particularly the freedom to incorporate innovative designs and strategies, is greatest at the very beginning of vehicle conceptual design. Conversely, this is when the least knowledge of the product exists. As product content decisions are made the level of freedom in the design decreases and the design becomes "locked in." The majority of vehicle lifecycle cost is also set by the end of vehicle conceptual design. This makes it critical to make well-informed and validated decisions in the concept design phase to avoid expensive iterations and redesign in the detailed design phase. Parametric vehicle modeling permits rapid …

A Phenomenological Study Of College Seniors In A Performing Arts Music Program, Eric Lapin

All Dissertations

Music has been an integral component of higher education dating back to the Middle Ages. As higher education developed in American institutions a traditional degree program began to emerge. Students in American higher education music programs focused on either performance or music education. However, a review of the literature has shown that these traditional programs are rife with limitations, and in many cases are not properly preparing students. As a result, Performing Arts style undergraduate degree programs are gaining popularity. These Performing Arts programs seek to offer a more comprehensive music and arts experience that more adequately prepares graduates for …

Validation Of Thermal Destruction Of Pathogenic Bacteria In Rendered Animal Products, Mary Hayes

All Dissertations

This study tested enumeration techniques for high fat food matrices and determined thermal death times in rendering animal products. Standard Class O phosphate/magnesium chloride dilution buffer series (Dilution Series A) and a modified (pre-warmed to 32oC) lecithin phosphate dilution buffer series (Dilution Series B) were used to enumerate a Salmonella cocktail from both poultry and beef rendering materials. Results of this study indicate use of a modified lecithin buffer did not improve Salmonella enumeration accuracy from rendering materials. Instead, the results suggested use of xylose lysine deoxycholate agar (XLD) with either buffer system accurately enumerated Salmonella from rendering materials. The …

Understanding The Role Of Requirements In Engineering Design By Novices, Shraddha Joshi

All Dissertations

Requirements play a critical role in the design process. The broader impact of this research is to develop a systematic understanding of the current use of requirements with an ultimate goal to develop guidelines and recommendations for more effective use of requirements throughout the design process. Thus, this research begins to answer the question about what is the role of requirements in design process and, specifically, its role in idea generation? The answer to this question is explored in three phases. The first phase is to understand how requirements are currently taught to students. To that end, two surveys were …