Clostridium perfringens is a significant human pathogen, causing 250,000 cases of food poisoning in addition to several thousand potentially lethal cases of gas gangrene each year in the United States. Historically, work in this field has centered around toxin production, as C. perfringens can produce over 13 toxins. This work expands the knowledge of the starvation-response of C. perfringens, which includes several potential virulence factors, sporulation, motility and biofilm formation. Sporulation protects cells from a variety of stresses, including starvation. Efficient sporulation requires the transcriptional regulator CcpA, mediator of catabolite repression. Sporulation is repressed by glucose, but, surprisingly, in a CcpA-independent fashion. C. perfringens cells in a biofilm are resistant to a number of environmental stresses, including oxygen and antibiotics. Biofilm formation is repressed by glucose, and other carbohydrates, independently of CcpA. Gliding motility, a type four pili (TFP)-dependent phenomenon, affords C. perfringens with a mechanism for moving across a solid surface in response to carbohydrate starvation, while carbohydrates supplementation at high levels delay the initiation of the motility response. CcpA is required for the proper initiation of motility, a ccpA^-C. perfringens strain showed a considerable increase in the time to initiation of motility on lactose and galactose, and was unable to move at all in the presence of glucose. Gliding motility represents the most significant finding of this work. TFP were previously undescribed in any Gram-positive bacterial species, and this work produced genetic evidence suggesting their presence in all members of the clostridia, and physical evidence for TFP-dependent gliding motility in a second species, C. beijerinckii. / Ph. D.

Due to the cost and difficulty of conducting direct tensile and compression creep testing on engineering ceramics, four-point bending creep test methods are often used as an alternative. Stress distribution in the bending specimen is nonlinear, so a proper interpretation method is needed to get creep properties from data produced by four-point bending creep tests. The method of Hollenberg et al. and the method of Chuang are among the methods to predict the creep parameters from bending creep test data. However, bending creep test methods are often doubted for quantitative creep analysis with reasons like uncertainties from contact point shift or frictional effects in four-point bending creep tests. Finite element simulations of the four-point bending creep tests were performed to evaluate the limitations and abilities of four-point bending creep tests and the methods to predict creep parameters from bend test data. Material model for asymmetric creep behavior (different creep rate in tension and in compression) of ceramics material were developed by modifying the existing symmetric creep model and implemented in the inhouse non-linear finite element code. Explicit finite element method (dynamic relaxation) was successfully used to consider both, the frictional effects between loading rollers and specimen, and asymmetric creep properties of ceramics material. The developed asymmetric creep material model was verified by the simulation of C-ring compression creep test and comparison with published experimental data. It was found that when friction between loading rollers and specimen was not applied in the simulations, both Hollenberg’s and Chuang’s methods well predicted creep parameters from bend creep simulation data. But, when friction was high as in normal bend creep tests, the pre-exponent (A) was highly underestimated. Prediction of stress exponent (n) was not affected much by friction. Bend test set-up with rolling-pins in ASTM C 1211 was recommended to reduce the frictional effects in bend creep tests and a proof simulation was performed. The simulation showed that the test set-up in ASTM C 1211 effectively removed the frictional effect of the frequently used creep test set-up and the effect of bending moment increase due to the rolling of loading pin was minor. / Thesis / Master of Applied Science (MASc)

The next generation of toxic chemicals and hazardous wastes from sophisticated chemical industries will demand the environmental agencies to employ biological methods over the conventional physical and chemical remediation methods. Over the past decade, natural metallo-enzymes have been identified to degrade some of the major chemical contaminants through electron transfer pathways. However, these natural enzymes are less stable in organic solvents and they are not effective for the degradation of toxic compounds such as polychlorinated biphenyls or dioxins. This thesis explores the use of protein design approaches to produce chemically and molecularly modified enzymes, which are highly stable, possess little substrate specificity, and have higher activity than the natural enzymes. The experiments presented in this thesis make use of solid phase synthesis and site-directed mutagenesis for the synthesis and production of these enzymes and popular chromatographic techniques for their purification. The partial characterization of these proteins revealed the essential structural features of these proteins, and their catalytic activity was demonstrated by the use of peroxidase assays. / Master of Science

Yes / The near-trapping effects on wave-induced dynamic seabed response and liquefaction close to a multi-cylinder foundation in storm wave conditions are examined. Momentary liquefaction near multi-cylinder structures is simulated using an integrated wave-structure-seabed interaction model. The proposed model is firstly validated for the case of interaction of wave and a four-cylinder structure, with a good agreement with available experimental measurements. The validated model is then applied to investigate the seabed response around a four-cylinder structure at 0° and 45° incident angles. The comparison of liquefaction potential around individual cylinders in an array shows that downstream cylinder is well protected from liquefaction by upstream cylinders. For a range of incident wave parameters, the comparison with the results for a single pile shows the amplification of pressure within the seabed induced by progressive wave. This phenomenon is similar to the near-trapping phenomenon of free surface elevation within a cylinder array. / Energy Technology Partnership (ETP), Wood Group

Since the discovery of superconductivity, its fantastic properties have fascinated the scientific community. The discovery of high critical temperature (Tc) superconducting compositions further inspires the wide applications of superconductors with relatively inexpensive liquid nitrogen cooling. Recently, the integration of superconductivity and optical waveguides has put forward the potential for ultrasensitive, ultra-fast and ultralow noise light detectors. However, simple and cost effective superconductor designs and fabrication processes are still required to enable wide implementation. The objective of this research was to study the fabrication of the superconductor core fibers with a fused silica cladding via the melt-draw approach, as well as develop appropriate characterization techniques to describe the fibers produced. In addition, a further objective was to determine the cooling efficiency of ordered holes around a superconductor core and construction of a one dimensional (1-D) single-phase steady state model to predict the heat transfer during cryogenic liquid transfer inside glass tube. In this thesis, both Pb and YBCO superconductor core fibers with fused silica cladding have been demonstrated. The fibers were fabricated via the melt-draw technique and maintained overall diameters ranging from 200-900 μm and core diameters of 100-800 μm. Surface morphology, chemical composition, interface effect, and superconductivity were further investigated. Surface morphology analysis confirmed that the Pb and YBCO core fibers possessed good circularity and clean interfaces between the core and cladding. Both the Pb and YBCO cores were relatively dense after the melt-draw process. The melt-draw process avoided contamination during fabrication as indicated by the composition analysis. Limited PbO was examined on the Pb core surface but further action will be required to detect the source of oxygen. The YBCO core maintained a stoichiometric ratio comparable to the superconducting phase even after the melt forming process. The elemental mapping showed that limited cross-diffusion occurred between the Pb core and fused silica cladding. Conversely significantly more elemental cross interaction between the core and cladding was noted for the YBCO core fiber. Superconductivity of the Pb core was verified by a custom designed four-probe technique in liquid helium. The YBCO core was also confirmed to be superconductive after heat treatment with O₂ present. The feasibility of efficient cooling by the holey glass tubes was confirmed. A 1-D single-phase steady state model was constructed to evaluate the heat transfer mechanism. The experimental results are in reasonable agreement to the theoretical calculation. / Master of Science

<p dir="ltr">In response to the evolving demands of todays competition, there is a growing expectation for enhanced services to industry and academic enterprises. This thesis explores the application of System Engineering methodologies as a strategic approach to securing success with both industrial and academic enterprises. Industry faces issues with the absence of a positive tone, inefficiencies and delays in delivery, and customer satisfaction. Meanwhile, academia faces several challenges including lack of communication between departments, how to allocate institutional resources to simplify student experience, reduce complexity in<br>students college experience, and lack of students motivation. These issues for students lead to poor academic performance, financial struggles, and possibly mental health problems. There is a recognized need for a systematic approach to ensure student success at universities. A fundamental approach emerges in the form of Collective System Design (CSD) to find ways to address the above- mentioned challenges. Collective System Design is explored for ad- dressing the challenges faced by academic organizations and industrial processes. Collective System Design aims to improve the long-term viability of an enterprise by fostering<br>sustainability and success. This thesis further investigates the Collective System Design Language, offering a communication tool for design and an approach to assess effectiveness before implementation.<br>This thesis highlights two case studies: Shuttleworth (manufacturing industry) and the Purdue University Fort Wayne Student Success Standard Process Lifecycle.<br>The impact of solving these problems can be measured through several key indicators:<br>Shuttleworth (Manufacturing Industry).<br>• Reduction in Lead Time<br>• In on-time Delivery<br>• Enhanced Customer Satisfaction and improvement in product quality.<br>Purdue University Fort Wayne.<br>• Improvement in Student Experience and Quality of Life.<br>• Achievement of Student Wellness Functional Requirements and improvements in student retention and four and five year graduation rates.<br>Achievement of Student Success Functional Requirements and improvements in student retention and four and five year graduation rates.<br>There are three main objectives of this thesis: (1) Apply and contrast the application of Collective System Design principles across a manufacturing industrial client and a service enterprise, namely higher education (2) Offer a systematic approach for manufacturing to improve on-time delivery, enhance customer satisfaction, create positive tone by using the<br>principles of Collective System Design, and (3) For academia, develop a System Design Decomposition to define the functions of the university to foster student wellness according to four viewpoints: academic, financial, career, and living wellness. The objective is to incorporate the development of a System Design Decomposition that provides methodology to ensure that student wellness outcomes consider the four viewpoints of wellness (Academic, Financial, Career, and Living). The Student Success Standard Process Lifecycle defines standard processes in all process steps that will facilitate the desired student experience and four wellness outcomes. The lifecycle consists of Student Success States where the lifecycle<br>begins from S0 (learning about university) to S7 (Supportive alumni) and defines standard process steps in each state. Each standard process step seeks to achieve the Functional Requirements from the four wellness viewpoints (academic, financial, career, and living) in Student Success Standard Process Lifecycle. <br>The Collective System Design Decomposition methodology will serve as a structured approach to defining desired student wellness outcomes within a Rapid Design Process, which takes place in the first session focusing on defining outcomes. By leveraging this framework of four wellness viewpoints, the thesis aims to address issues with defining the outcomes<br>for academic, financial, career, and living wellness viewpoints. Each wellness viewpoint has specific Functional Requirements (outcomes) that need to be defined and achieved by Student Success Standard Process Lifecycle and Rapid Design Process, to ultimately enhance student<br>success and well-being at Purdue Fort Wayne University.</p>

This thesis is a study in the application of kinematics coupled with elastic body mechanics. Most studies in kinematics assume all mechanism links to be inelastic. Furthermore, the methods of kinematic synthesis have generally been developed to meet requirements of displacement, velocity and acceleration. The work presented in this thesis differs in two important aspects. First, one grounded link of a four-bar linkage is replaced by a cantilevered beam in flexure to produce a force generating mechanism. Second, the synthesis method presented here allows the generation of these mechanisms in closed form for prescribed force generation. A compound archery bow that incorporates four-bar linkages has been developed as an example. This design relies on the non-linear mechanical advantage of the four-bar linkage and the bow mechanics to provide a resistance curve that is more compatible with the human strength curve. In addition, by modifying the bow kinematics, more potential energy can be stored, and thus potentially more kinetic energy can be transferred to the arrow than with previous bows. / Master of Science

In designing devices to produce straight-line motion, the designer has a fundamental choice between selecting sliding devices or selecting pinned linkages. Although they are more complex to design and implement, linkages will often prove a less expensive, more efficient, and generally more satisfactory option than simple sliders. The objective of this thesis is to provide a tool to the designer that serves as an aid in making intelligent decisions in the selection of four-bar linkage type straight-line-mechanisms. This thesis provides research into the selection, evaluation, and implementation of existing straight-line mechanism designs. Twenty-two straight-line mechanisms are compared for both compactness and fidelity of the straight-line path. Also, figures showing position, velocity, and acceleration of each a included. The functional product of to this work is a software program called Straight-line. Straight-line gives the designer a graphical environment from which a wide variety of straight-line mechanisms can be quickly analyzed and evaluated. The software also provides a new type-synthesis technique that allows the designer to generate a straight-line-mechanism by graphically inputting a desired path. / Master of Science

Studien har utgått ifrån Freebodys och Allan Lukes modell (Freebody &amp; Kindenberg, 2019 ref. i Aldén &amp; Bigestans, 2018, s. 279–280), the four resources model som identifierar fyra olika lässtrategier som inlärare behöver för att utveckla för att bli kompetenta läsare. Modellens lässtrategier (avkodare, textdeltagande, textanvändare och textanalytiker) används för att undersöka hur inlärare i svenska som andraspråk får möjlighet att utveckla sin kritiska läsförståelse. Detta har gjorts genom att studera tre olika läromedel som används i våra egna verksamheters svenska som andraspråksundervisning i åk 7–9. Studien genomfördes som en läromedelsundersökning med stöd av ett kodschema baserat på modellen samt en kvalitativ innehållsanalys.   Läromedlen erbjuder inläraren möjlighet att träna på lässtrategierna utifrån modellen the four resources model i olika utsträckning men både Fixa Texten 1 (Sahlin, 2018), Jalla Jalla – raka vägen! C (Andersson &amp; Ojala, 2018) samt Svenska Impulser 9 (Markstedt &amp; Peña, 2023) har inslag som kan användas för att utveckla inlärarnas kritiska läsning samt den generella läsförståelsen. Beroende på läromedel kan vissa lässtrategier och material behöva kompletteras utifrån inlärarnas behov. Slutsatsen är att Jalla Jalla – raka vägen! C är den mest kompletta för utveckling av läsförståelse utifrån the four resources model enligt vår läromedelsundersökning.

Since COVID-19 pandemic, flexible work arrangements have been in vogue. People have started to rethink their way of living and especially their way of working. The well-being of employees has become a priority in this fast-changing economy. Improving well-being includes finding balance between personal and professional lives, which can be achieved through different flexible work arrangements. In this thesis, we explore the specific model of the four-day workweek (4DWW). The 4DWW can be implemented with condensing the same number of hours of a 5-day workweek in 4 days or simply with the reduction of the number of hours worked in total. In this thesis, we choose to focus on a reduced number of working hours, as we believe a condensed version of a 5-day workweek in 4 days would not be sustainable and would possibly lead to burn-out.  The 4DWW has received a lot of attention in the 1970s, but only as a condensed version of the five-day workweek and has come back in the literature since the Covid-19 pandemic. It has mostly been studied during a trial run of a few months, measuring its impact only while being under study. The Hawthorne effect shows that data can be biased while being under study, and the fact that the 4DWW is observed only for a few months can make the analysis seem out of time. We wanted to dig deeper and observe the influence of the 4DWW when it has been implemented for several years. This study investigates the influence of the 4DWW on employees and the organizing of work in the long run, paying attention to changes that are persistent after several years of implementation and stretch beyond the ones that are mainly present in the beginning.  The 4DWW is a flexible work arrangement that can have different purposes such as improving well-being and increasing productivity. The aim of the study was to analyse the influence of the 4DWW on both levels, the individual employee level and the level of the organization as a functioning dynamic between employees. Our thesis aims to observe how the well-being and productivity of employees are influenced by the 4DWW, and how the coordination can be adjusting to this fast-paced work rhythm, focusing on the collaboration and the surveillance at work. This thesis gains perspective on this subject and aims to expose practical implications for employees and their ways of working together to inform and broaden people’s minds and theoretical knowledge about flexible work arrangements, especially the 4DWW concept.