Determining the presence of an analyte of interest, and finding the enantiomeric purity of chiral molecules are challenging tasks. This work in molecular recognition is carried out routinely by many different researchers, including both academic as well as industrial research groups. The following dissertation presents original research directed toward two different areas of interest to the molecular recognition community: enantioselective sensing in solution, and sensing at a defined interfacial environment. This work begins with a review of the non-chromatographic ways that the enantiomeric purity of chiral carboxylic acids is determined, presented in Chapter 1. Carboxylic acids are important functional groups, both for organic synthesis as well as pharmaceutical drug development. Chapter 2 presents efforts that have been made to rapidly assess both the enantiomeric purity and identity of chiral carboxylic acids, utilizing the technique of exciton-coupled circular dichroism (ECCD). A twist is imparted on a complex, and can be correlated with the absolute configuration of the stereocenter. The enantiomeric composition can be rapidly determined. After creating the assay, the focus of the work shifted toward applying this system to new classes of analytes. Chapter 3 covers chemo- and enantioselective differentiation of [mathematical symbol]-amino acids, and continues to discuss the expansion to [mathematical symbol]-homoamino acids. Then a synthetic substrates was tested, and a series of reactions screened to determine if any enantioselectivity had been imparted by a Baeyer-Villiger oxidation. Finally, the enantiomeric composition of a biaryl atropisomer, a compound lacking a stereocenter, was determined. The signal produced from this assay is at a relatively short wavelength, and efforts were undertaken to push this signal to longer wavelength. Chapter 4 is a compendium of the lessons that were learned upon attempting to create a self-assembled sensing system. The final chapter details work that was done in collaboration with Professor Katsuhiko Ariga at the National Institute of Materials Science in Tsukuba, Japan. In this chapter, an indicator displacement assay was carried out for the first time at the air-water interface. This contribution opens the door for sensing to be carried out at defined regions, rather than free in bulk solution. / text

This research was able to identify a wide range of elements present in fresh volcanic ash from a 2010 eruption in Indonesia using varied instrumental neutron activation analysis techniques. The ash was then leached into slightly acidic distilled water meant to simulate rainwater. This thesis focuses both on the methods used to identify the elements present in the ash, as well as the possible impacts of the results. The research included the use of both thermal and epithermal neutron irradiations from the University of Texas's TRIGA research reactor in conjunction with a high purity germanium detector (HPGe) with a Compton suppression system. The leachate was analyzed by an inductively coupled plasma mass spectrometer (ICP-MS), and the results were compared to the original material present in the ash. Several potentially toxic metals and metalloids leached out of the system at relatively high rates. For example, 2.7% of the original antimony present in the ash leached into the simulated rainwater, as well as 1.7% of the original nickel, and 0.71% of the original arsenic. However, the concentrations of the elements identified in the ash were mostly similar to average crustal rock, and the concentrations of the elements identified in the leachate were not determined to be at toxic levels. The total amount of each element released during the eruption was also calculated based on the estimate of 160 million tonnes of ash released during the eruption, which was determined by a different study. / text

Asphaltene precipitation, flocculation, and deposition in the reservoir and producing wells cause serious damages to the production equipment and possible failure to develop the reservoirs. From the field production prospective, predicting asphaltene precipitation, flocculation, and deposition in the reservoir and wellbore may avoid high expenditures associated with the reservoir remediation, well intervention techniques, and field production interruption. Since asphaltene precipitation, flocculation, and deposition strongly depend on the pressure, temperature, and composition variations (e.g. phase instability due to CO2 injection), it is important to have a model that can track the asphaltene behavior during the entire production system from the injection well to the production well, which is absent in the literature. Due to economic concerns for asphaltene related problems, companies spend a lot of money to design their own asphaltene inhibition and remediation procedures. However, due to the complexity and the lack of knowledge on the asphaltene problems, these asphaltene inhibition and remediation programs are not always successful. Near-wellbore asphaltene inhibition and remediation techniques can be divided into two categories: changing operating conditions, and chemical treatment of the reservoir. Although, the field applications of these procedures are discussed in the literature, a dynamic model that can handle asphaltene inhibition and remediation in the reservoir is missing. In this dissertation, a comprehensive non-isothermal compositional reservoir simulator with the capability of modeling near-wellbore asphaltene inhibition and remediation is developed to address the effect of asphaltene deposition on the reservoir performance. This simulator has many additional features compared to the available asphaltene reservoir simulators. We are able to model asphaltene behavior during primary, secondary, and EOR stages. A new approach is presented to model asphaltene precipitation and flocculation. Adsorption, entrainment, and pore-throat plugging are considered as the main mechanisms of the asphaltene deposition. Moreover, we consider porosity, absolute permeability, and oil viscosity reductions due to asphaltene. It is well known that the asphaltene deposition on the rock surface changes the wettability of the rock towards oil-wet condition. Although many experiments in the literature have been conducted to understand the physics underlying wettability alteration due to asphaltene deposition, a comprehensive mathematical model describing this phenomenon is absent. Based on the available experimental data, a wettability alteration model due to asphaltene deposition is proposed and implemented into the simulator. Furthermore, the reservoir simulator is coupled to a wellbore simulator to model asphaltene deposition in the entire production system, from the injection well to the production well. The coupled reservoir/wellbore model can be used to track asphaltene deposition, to diagnose the potential of asphaltene problems in the wellbore and reservoir, and to find the optimum operating conditions of the well that minimizes asphaltene problems. In addition, the simulator is capable of modeling near-wellbore asphaltene remediation using chemical treatment. Based on the mechanisms of the asphaltene-dispersant interactions, a dynamic modeling approach for the near-wellbore asphaltene chemical treatments is proposed and implemented in the simulator. Using the dynamic asphaltene remediation model, we can optimize the asphaltene treatment plan to reduce asphaltene related problems in a field. The results of our simulations show that asphaltene precipitation, flocculation, and deposition in the reservoir and wellbore are dynamic processes. Many parameters, such as oil velocity, wettability alteration, pressure, temperature, and composition variations influence the trend of these processes. In the simulation test cases, we observe that asphaltene precipitation, flocculation, and deposition can occur in primary production, secondary production, or EOR stages. In addition, our results show that the wettability alteration has the major effect on the performance of the reservoir, comparing to the permeability reduction. During CO2 flooding, asphaltene precipitation occurs mostly at the front, and asphaltene deposition is at its maximum close to the reservoir boundaries where the front velocity is at its minimum. In addition, the results of the coupled reservoir/wellbore simulator show that the behavior of asphaltene in the wellbore and reservoir are fully coupled with each other. Therefore, a standalone reservoir or wellbore simulator is not able to predict the asphaltene behavior properly in the entire system. Finally, we show that the efficiency of an asphaltene chemical treatment plan depends on the type of dispersant, amount of dispersant, soaking time, number of treatment jobs, and the time period between two treatment jobs. / text

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

A novel approach to miniaturizing an 802.11b WLAN card using folded-flex ultra-thin substrates is presented. A 73 percent reduction in size was realized using hybrid circuits on FR4 and polyimide. There is even more potential for further reduction if more copper layers are used. The miniaturized 802.11b WLAN cards were used to design 802.11b wireless sensor nodes. A research test-bed was setup to study how 802.11b networked sensor nodes could operate in the field. There are many applications for such sensor networks like habitat monitoring, object tracking, seismic detection, military surveillance, or fire detection to name a few. This investigation focuses on the requirements, design, and performance of a miniaturized 802.11b wireless LAN sensor node that is reliable, can be deployed in large-scale, and has the endurance long-lived for surveillance applications. An aperture coupled microstrip antenna is investigated for 2.44 GHz wireless local area networks (WLAN) which has the advantages of being low-profile and compact. The most important parameters for antenna optimization have been determined through extensive simulation using Ansoft's HFSS and experimental verification. As a result, an omnidirectional antenna with a size of 36.2 mm x 32 mm x 4.75 mm has been realized using Rogers 5880 duroid (permittivity = 2.20 ; loss tangent = 0.0004) with 4.4 dBi of gain, > 80 MHz, and a return loss > -32 dB. These types of performance characteristics make the antenna highly desirable for both 802.11b and Bluetooth applications.

Not available / text

The radiological dispersal device (RDD) is a weapon of great concern to those agencies responsible for protecting the public from the modern age of terrorism. In order to effectively respond to an RDD event, these agencies need to possess the capability to rapidly identify the radiological agents involved in the incident and assess the uptake of each individual victim. Since medical treatment for internal radiation poisoning is radionuclide-specific, it is critical to identify and quantify the radiological uptake of each individual victim. This dissertation describes the development of automated analytical components that could be used to determine and quantify multiple radionuclides in human urine bioassays. This is accomplished through the use of extraction chromatography that is plumbed in-line with one of a variety of detection instruments. Flow scintillation analysis is used for ⁹⁰Sr and ²¹⁰Po determination, flow gamma analysis is used assess ⁶⁰Co and ¹³⁷Cs, and inductively coupled plasma mass spectrometry is used to determine actinides. Detection limits for these analytes were determined for the appropriate technique and related to their implications for health physics.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18990号 / 工博第4032号 / 新制||工||1621 / 31941 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 引原 隆士, 教授 北野 正雄, 准教授 山田 啓文 / 学位規則第4条第1項該当

Skeletal muscle is a major organ comprising 30-40% of the human body mass. The coordination of processes resulting in mature muscle requires many genes, and their loss can result in debilitating muscle disorders. Of the strategies being developed to cure muscle diseases, enhancement of the natural process of muscle cell fusion in existing or introduced myogenic cells has great therapeutic potential. In this work, we determined whether a drug that stimulates proliferation and fusion of myoblasts could alleviate murine Duchenne muscular dystrophy. We also studied the necessity of a gene that is upregulated in early fusing human myoblast cultures and its role in muscle disease development.

<p>Mechanical oscillators form the primary structure of a wide variety of devices including energy harvesters and vibration absorbers, and also have parallel systems in electrical fields for signal processing. In the area of wave propagation, recent study in periodic chains have focused on active tuning methods to control bandgap regions, bands in the frequency response in which no propagating wave modes exist. In energy harvesting, several coupled systems have been proposed to enhance the peak power or bandwidth of a single harvester through arrays or dynamic magnification. Though there are applications in several fields, the work in this dissertation can all fit into the category of coupled non-linear oscillators. In each sub-field, this study demonstrates means to advance state of the art techniques by adding nonlinearity to a coupled system of linear oscillators, or by adding a coupled device to a nonlinear oscillator.</p><p>The first part of this dissertation develops the analytical methods for studying wave propagation in nonlinear systems. A framework for studying rotational systems is presented and used to design an testbed for wave propagation experiments using a chain of axially aligned pendulums. Standard analytical methods are also adapted to allow uncertainty analysis techniques to provide insight into the relative impact of variations in design parameters. Most analytical insight in these systems is derived from a linearlized model and assumes low amplitude oscillations. Additional study on the nonlinear system is performed to analyze the types of deviations from this behavior that would be expected as amplitudes increase and nonlinear effects become more prominent.</p><p>The second part of this dissertation describes and demonstrates the first means of passive control of bandgap regions in a periodic structure. By imposing an asymmetrical bistability to an oscillator in each unit cell, it is analytically shown that each potential well has different wave propagation behaviors. Experimental demonstrations are also provided to confirm the simulated results.</p><p>The final section performs analytical and numerical analysis of a new system design to improve the performance of a nonlinear energy harvester by adding an excited dynamic magnifier. It is shown that this addition results in higher peak power and wider bandwidth than the uncoupled harvester. Unlike standard dynamic magnifiers, this performance does not come at the expense of power efficiency, and unlike harvester arrays, does not require the added cost of multiple energy harvesters.</p> / Dissertation