Pulse power system is widely used for medical, industrial and military applications. The operational principle of the pulse power system is that the energy from the input source is stored in the capacitor bank or superconducting inductive device through a dc-dc converter. Then, when a discharging signal exists, the stored energy is released to the load through pulse forming network (PFN) generating high peak power pulse up to gigawatts within several tens of or hundreds of microseconds. The pulse power system has been originally developed for the defense application. After the format of the voltage compression and voltage addition stages for the short-pulse high power acceleration has been established, it has been evolved to be common. Then, its application has been extended to food processing, medical equipment sterilization and wastewater treatment since many present environmental problems have been known in the early 70's or even earlier. In addition, the pulse power system is newly spotlighted due to the recent world events. The application examples are to treat anthrax-contaminated mail, and the use of accelerators to produce high power X-rays for security screening. Furthermore, the pulse power system has been applied for the tactical weapon system such as electrothermal-chemical (ETC) gun, coilgun and active armor system. Because the pulse power system applied for the tactical weapon system has the potential to be integrated in the military vehicle, a compact, lightweight pulse power system is strongly required for the future weapon system. In this thesis, a distributed power system (DPS) for the capacitor charger is introduced for the application of the active armor system. Furthermore, a design methodology is presented for the front-end converter to achieve the high efficiency as well as the high power density. Design parameters are identified and their impact on the design result is studied. the optimal operating point is determined based on the loss comparison between different operating points. In order to further improve the power density utilizing the unique operation mode i.e. pulse power operation, transformer design using amorphous-based core is provided and the design result is compared with that using ferrite-based core. A 5 kW prototype converter is built up and the experimentation is performed to verify the design. / Master of Science

Accessibility in back-end development is often overlooked, with the majority of discussions and efforts centered on front-end design. To make applications usable for a wider audience, developers must also prioritize incorporating accessibility from the back-end. Back-end web accessibility encompasses the design and development of web-based systems and applications that are accessible to all users, including those with disabilities. This involves optimizing the underlying code and infrastructure for accessibility and implementing features that enable users with disabilities to navigate and interact with the site or application. Ensuring back-end web accessibility is crucial for creating an inclusive online environment accessible to everyone, regardless of their abilities. Presently, there is a significant gap in research regarding back-end accessibility specifics. This study investigates the challenges in implementing back-end accessibility, explores best practices, and aims to facilitate future research on its impact on user experience and system performance.

No / Many data warehouses are currently underutilized by managers and knowledge workers. Can high-quality end-user metadata help to increase levels of adoption and use?

An experimental investigation was conducted to study the extended end-plate moment connections subjected to cyclic loading. Seven specimens representing three end-plate moment connection configurations commonly used in the pre-engineered building industry were used. The connections were designed using yield-line theory to predict end-plate yielding and the modified Kennedy method to predict maximum bolt force calculations including prying action. A displacement controlled loading history was used to load the specimens. The maximum moments obtained experimentally and the experimental bolt forces throughout loading were compared with analytical predictions and finite element model results. The inelastic rotation of connections was calculated and conclusions were drawn on the compliance of these connections with current AISC specifications. / Master of Science

yes / A mechanism analysis based on the upper-bound theorem of concrete plasticity is developed to predict the critical failure plane and corresponding shear capacity of reinforced concrete dapped-end beams. Failure modes observed in physical tests of reinforced concrete dapped-end beams are idealised as an assemblage of two moving blocks separated by a failure surface of displacement discontinuity. The developed mechanism analysis rationally represents the effect of different parameters on failure modes; as a result, the predicted shear capacity is in good agreement with test results. On the other hand, empirical equations specified in the Precast/Prestressed Concrete Institute design method and strutand-tie model based on ACI 318-05 highly underestimate test results. The shear capacity of dapped-end beams predicted by the mechanism analysis and strut-and-tie model decreases with the increase of shear span-to-full beam depth ratio when failure occurs along diagonal cracks originating at the bottom corner of the full-depth beam, although the shear span-to-full beam depth ratio is ignored in the Precast/Prestressed Concrete Institute design method.

A Case Study Using Scenario-based Design Tools and Techniques in the Formative Evaluation Stage of Instructional Design: Prototype Evaluation and Redesign of a Web-Enhanced Course Interface. The main purpose of this study was to augment the formative evaluation process of instructional design through the incorporation of scenario-based design tools and strategies that focus on interface design. The test population was students from undergraduate "human development" courses at Virginia Tech, approximately 250 students. One prototype of a course web interface was tested and revised based on data collected during the formative evaluation process. The scenario data provided rationale for redesign considerations. / Ph. D.

Two chemical methods, multi-reducing end modification and bleach oxidation, were used to prepare polysaccharide aldehydes and ketones. Their derived hydrogels and microgels were made for potential drug-delivery applications. Polysaccharide aldehydes and ketones are reactive intermediates for adding other functional moieties through chemo selective reactions such as Schiff-base formation or reductive amination. The most widely used method to prepare polysaccharide aldehydes is periodate oxidation. However, this method impacts higher-order polysaccharide structure, decreases degree of polymerization (DP), and increases polysaccharide instability, leading to degraded mechanical properties. Developing a new method to prepare polysaccharide aldehydes while preserving DP, stability, and desirable physical properties is challenging. Inspired by the reactive reducing ends of polysaccharides, which are the anomeric carbons (at the chain end), one per natural polysaccharide molecule, that (for aldose-based polysaccharides) is in equilibrium between a ring-closed hemiacetal and an open-chain aldehyde form, we developed a novel method to prepare polysaccharide aldehydes by attaching monosaccharides to polysaccharide chains. Herein, we describe the approach of attachment through amination between amine group at the C2 position of the monosaccharide and carboxylic acid groups on polysaccharides. In this way, more reducing ends (C1 of the monosaccharide) can be introduced to the polysaccharides. We have chosen to call this new family of polysaccharides "multi-reducing end polysaccharides (MREPs)". We call this method "multi-reducing end modification". We then fabricated injectable, self-healing, fast gelling Schiff base hydrogels based on MREPs. Previous methods to fabricate Schiff base polysaccharide hydrogels usually required periodate oxidation which leads to degraded mechanical properties, with gelation time typically from minutes to hours. We employed acetic acid to induce fast gelation of our MREPs hydrogels within seconds. The Schiff base MREP hydrogels exhibited self-healing and injectable behavior with limited cytotoxicity, which is promising for future biomedical applications such as targeted drug delivery or tissue engineering. Microgels are dispersible but undissolvable colloids of three-dimensional polymer networks with numerous applications. We synthesized all-polysaccharide microgels (herein, we use the general term "microgels" to describe small gel particles of nanometer to micron diameters) using oxidized hydroxypropyl cellulose (Ox-HPC), carboxymethyl chitosan (CMCS), and calcium chloride. By tuning the calcium concentration, uniform microgels can be obtained with gel size in the hundreds of nanometers. Model amine-containing drugs such as picloram or p-aminobenzoic acid (pABA) can be chemically attached to Ox-HPC through Schiff base chemistry, creating imine bonds that are reversible in water, thereby permitting slow release. This class of all-polysaccharide microgels showed promising applications in agriculture, such as controlled release of agrochemicals. We anticipated that these strategies would benefit future polysaccharide chemistry research and permit synthesis of novel hydrogel or microgel systems with potential drug-delivery applications. / Doctor of Philosophy / Polysaccharides are long chains composed of sugar units ("sugar polymers"). Many natural-derived polysaccharides are sustainable, biodegradable and have low toxicity. Hydrogels are composed of porous solids and water, similar to the structure of human tissues. "Microgels" are used herein to describe small gels of nanometer to micron diameters. Fabrication of polysaccharides into hydrogels or microgels can be advantageous for drug-delivery applications. Chemical modification of polysaccharides is usually required before making polysaccharide-based hydrogels or microgels. However, previously described methods usually destroy the chemical structure of polysaccharides and cause degradation. To overcome this challenge, we developed a non-destructive chemical modification method to prepare hydrogels without these disadvantages. This method also introduced a new concept in polysaccharide science. Following our novel chemical modification method, polysaccharide-based hydrogels were made. Compared to the previous polysaccharide hydrogels which usually required long gelation times, our polysaccharide hydrogels gel within seconds with addition of tiny amounts of vinegar. Besides, our polysaccharide-based hydrogels are injectable and spontaneously repair themselves with low toxicity to cells. These properties make our hydrogels promising for cancer-targeted drug delivery. Food is the first necessity of human beings. Pesticides are often used in excessive amounts and in broad distribution, to guarantee high crop productivity. Excess use and/or distribution of pesticides can pollute to the environment and pose threats to human health. To solve this problem, we made all polysaccharide microgels, dispersed in benign water, that can permit slow release of pesticides, applied in a form that can promote great precision. Overall, we developed new ways to modify polysaccharides to create effective and harmless hydrogels or microgels. We aim to push the boundaries of science and benefit human society through our research.

Raman spectroscopy records the inelastic scattering of photons originating from striking a sample with monochromatic light. Inelastic, or Raman, scattered photons shift in wavelength due to excitation of the vibrational modes of molecules struck by the incident light. The Raman scattered photons are representative of all of the covalent bonds contained within a sample. Raman spectra taken of biological systems such as proteins, bacterial colonies, and liquid waste, are difficult to interpret due to the complexity of their covalent bond landscape and mixtures of molecules in highly variable concentrations. Rather than deconstructing Raman spectra to attempt assignment of specific bonds and functional groups to wavenumber peaks, here we have developed a chemometric analysis pipeline for quantifying the similarities and differences among a set of Raman spectra. This quantification aids in both classification of samples, and in measuring how samples change over time. The chemometric approach for interpretation of Raman spectra was made freely available in a user-friendly format via a MATLAB add-on called the Raman Data Analysis (RDA) Toolbox. Demonstrations of the RDA Toolbox functionalities on Raman spectra taken of various common biological systems are included, such as determination of protein concentration and monitoring bacterial culture growth. The RDA Toolbox and Raman spectroscopy are also used to initiate research in novel areas. Fast and accurate evaluation of enzyme specific activity is required for engineering enzymes, and results of Raman assays, evaluated in the RDA Toolbox, are successfully correlated to absorbance activity assays of an enzyme WT and mutant library. Further development of this research could alleviate the bottleneck of screening mutant libraries in enzyme engineering projects. The Toolbox is then used in a distinctly different application for evaluating urine and spent dialysate samples from patients with end stage renal disease. Categorization between samples from healthy volunteers and patients is accomplished with close to 100% accuracy, and evidence indicating that Raman spectroscopy can serve as an early diagnostic tool for infections of the peritoneal membrane is presented. / PHD / Raman spectroscopy, unlike other forms of spectroscopy, provides a complete picture of the chemical make-up of a sample. However, Raman spectra of biological samples are very difficult to interpret due to the complex mixture of molecules in living systems. Rather than trying to discern what specific molecules are in a sample, we have developed a method for measuring the similarities and differences among a set of Raman spectra. These measurements help us classify samples and monitor how samples change over time. We made a MATLAB add-on called the Raman Data Analysis (RDA) Toolbox to automate our method for interpreting Raman spectra, and made it available online for anyone to download and use. Raman spectroscopy and the RDA Toolbox are used to measure enzyme reaction speed, and the results compare favorably with a traditional method for measuring enzyme reaction speed. The final part of this dissertation focuses on using Raman spectroscopy and the RDA Toolbox to evaluate the health of patients with end stage renal disease (ESRD) by scanning urine and spent dialysate samples to detect failing kidney function or the onset of infection.

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No / Fatigue is a complex symptom commonly experienced by people with life-limiting illnesses. It has been identified in patients with, for example, cancer, heart failure, respiratory conditions, acquired immunodeficiency syndrome and renal failure. It is often rated by patients as having a greater effect on quality of life than pain. This article will explore the manifestations and consequences of fatigue. It will propose a minimum standard for its assessment and management and describe the implementation and evaluation of an audit, conducted in a hospice environment, designed to evaluate achievement of this standard. Although this audit was carried out in a hospice setting, the aim of the article is also to raise awareness of fatigue in all healthcare settings and to improve the assessment of this debilitating symptom.