The proliferation of mobile computing devices with powerful sensing and communication capabilities has created an immense social landscape of awareness and connectedness. Social media applications have been largely designed for asynchronous expression and collaboration among individuals. Though these models have served as suitable surrogates for social interaction in a rapidly evolving digital age, they have been insufficient at connecting people spatially and temporally. This report describes Revolver: an appli- cation utilizing the state-of-the-art in mobile and distributed computing to provide users with a shared sense of time and space. Revolver allows users to synchronously capture image data of their surroundings with the ability to virtually reconstruct an event from the separate sources. We present the ratio- nale for the project, design considerations, implementation details, results of the prototyping effort, and conclusions to carry this project to future phases of development for viable deployment. / text

Boronic acids, particularly those that carry an ortho-aminomethyl group, have been extensively utilized in the field of molecular recognition in recent years thanks to their ability to reversibly bind to a wide variety of polyol substrates. They have been shown to form cyclic boronate esters rapidly upon reaction with 1,2- and 1,3-diols, catechols, carbohydrates and hydroxycarboxylic acids, making them attractive as potential sensing units. While they have found broad application in this forum, the mechanism by which they work is still up for debate. This work begins in Chapter 1 with a review of the fundamentals of ¹¹B NMR spectroscopy and its application on the analysis of boronic acid-containing systems. The focus of Chapter 2 turns toward systems with an o-iminomethylphenylboronic acid moiety. This species can be formed easily through a three-component assembly, though physical understanding of this complex lags behind. With the fundamentals of ¹¹B NMR spectroscopy detailed previously, the results obtained when utilizing this technique to study both the structure and mode of interaction in these species will be presented. In Chapter 3 we give a comprehensive review of the data and conclusions that have been published by different groups about one of the most successful fluorescent sugar sensors of this kind, first introduced by Seiji Shinkai in 1994. Additionally, it delineates the experimental results obtained by our group when attempting to answer some of the remaining questions. In Chapter 4 we report the use of the aforementioned multi-component assembly as an enantioselective sensor for α-chiral primary amines. Using circular dichroism, the ee% of these analytes could be accurately determined with this system. Additionally, enantio- and chemodiscrimination was possible by employing chemometric tools like PCA and LDA. Finally, Chapter 5 is a compilation of efforts to expand the use of these sensing systems into synthetic organic chemistry research labs. In collaboration with Xumu Zhang at Rutgers University, we have implemented a previously developed system to analyze the product of an asymmetric hydrogenation of an imine to create a chiral amine. A proof of concept study on a novel automated circular dichroism plate reader prototype aimed to increasing sample throughput was completed at New York University with Professor Bart Kahr. / text

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No description available.

Accurate knowledge of the neutron flux distribution in a nuclear reactor has many tangible benefits. Perhaps the most important are the contributions to reactor safety. Detailed knowledge allows reactor operators to identify off-normal conditions quickly before they cause serious complications. Furthermore, reactor safety margins can be accurately quantified. As advanced reactor types are proposed, new sensor systems should be developed together with new algorithms for neutron flux reconstruction. This thesis develops neutron flux reconstruction methods for in-core sensors placed in HTRs. Sensor systems developed for current generation reactors cannot be used in HTRs. The high temperatures inside HTRs preclude the use of existing in-core sensors, and complex flux phenomena arising from the inner reflector and three-dimensional fuel block arrangements suggest that new flux reconstruction methods should be developed as well. Computer simulations were run to generate detailed in- core neutron flux distributions representative of HTRs. Next, this data was used to test two different flux reconstruction algorithms. It was found that the reconstruction algorithm based on the proper orthogonal decomposition performed better than the algorithm based on linear interpolation.

Thesis (M.S.)--Ohio University, November, 1998. / Title from PDF t.p.

Thesis (M. Phil.)--University of Hong Kong, 2000.

Recently, point-of-care diagnostics has gained great attention because it can improve patient’s quality of life. Electrochemical diagnostic systems are promising because of their miniaturizability and low-cost. However, fabrication of such devices requires special skills as well as expensive equipment and supplies. This thesis is based on a research project aimed at fabricating electrochemical sensors combing wax printing and inkjet printing or wax printing and hand painting. The electrochemical sensors can be used for measuring different kinds of electrochemical analytes like dopamine, uric acid by electrochemical methods like amperometry, which can show great calibration curve. The LOD of dopamine, uric acid, ascorbic acid, Nile Blue, hydrogen peroxide and ferrocene is 0.015 µM, 7.3 µM, 30 µM, 1.3 µM, 8 nM and 30 µM, respectively. Further, we can modify the electrochemical sensor by using multiwall carbon nanotube in order to improve the sensitivity of the electrochemical sensors. This modified electrochemical sensor can also be used as immunoassay by sandwich format ELISA for detecting carcinoembryonic antigen (CEA), which has been designated as a reliable biomarker for several types of cancers. We found that the CNT modified hand-painting device can detect CEA down to 0.6 ng/mL, which is three times lower than the cut-off value of diagnosis, i.e. 5 ng/mL in blood.

The modification of electrodes is always an important task in electrochemical detection of electroactive and biological molecules. Chemically modified electrodes can offer improved selectivity and sensitivity for the target analyte, which greatly enhance the electrode performance. Various materials such as conducting polymers, metal nanoparticles and carbon nanomaterials have been exploited and widely used for the modification of electrodes. Electrochemical or spontaneous deposition, electrostatic adsorption, layer-by-layer self assembly and covalent binding have also been developed for electrode modification and offer improved performance. Both Prussian blue (PB) and toluidine blue O (TBO) are excellent redox mediators and very popular in electrode modification. PB has shown strong catalytic property for the reduction of hydrogen peroxide, but the application in biosensor fabrication is limited for its instability at neutral pH. Graphene, as a single-atom-thick carbon material, is considered an ideal platform for designing composite nanomaterials for high-performance electrochemical or electrocatalytic devices. The combination of PB with reduced graphene oxide (RGO) and poly(toluidine blue O) (PTBO) will greatly improve the stability of PB. An amperometric biosensor based on glassy carbon (GC) electrode modified with reduced graphene oxide, PB and poly(toluidine blue O) was developed. Experimental results showed that the GC/RGO/PB/PTBO modified electrode offered an excellent electrocatalytic activity toward the reduction of hydrogen peroxide due to the possible synergistic effects of the PB-PTBO composite material. After codeposition of glucose oxidase (GOD) and chitosan (CHIT) coating, the resulting GC/RGO/PB/ PTBO/CHIT-GOD electrode exhibited excellent response to glucose with a sensitivity of 59 mA M1 cm2, a low detection limit of 8.4 μM and a linear range from 0.02 to 1.09 mM at a detection potential of +0.2 V vs. Ag.

Thin films of a wide variety of materials can be produced using an assortment of physical and chemical techniques. Such techniques are reviewed and compared, with particular reference to the deposition of tin oxide films. In the present study, MOCVD (Metal organic chemical vapour deposition) was used to grow thin films of tin oxide from dibutyltin diacetate precursor on a variety of substrates. A series of reactor prototypes were developed in accordance with specific requirements of reproducibility and process control. The evolution of the designs leading to the final working system is detailed. The theory of MOCVD is given with particular reference to the reactor used in this project. The effects of various deposition parameters on tin oxide film growth rates were investigated, and the results are discussed with reference to the deposition kinetics in the system. Films were characterised by optical interferometry, optical and electron microscopy, X-ray diffraction, Rutherford backscattering and electrical measurements. The films were generally uniform, conducting and polycrystalline, and were comprised of very small grains, resulting in a high density. A specific application of metal oxide materials is in solid state gas sensors, which are available in various forms and operate according to different mechanisms. These are compared and a detailed account is given on the theory of operation of surface conductivity modulated devices. The application of such devices based on tin oxide in thin film form was investigated in the present work. The prepared sensor samples were comprised of very small grains, resulting in a high density. The observation that preferred (310) orientation occurred in thicker films, can be attributed to dendritic growth. The sensors generally showed response to numerous reducing gas ambients, although there was evidence of a degree of selectivity against methane. Sensor response times due to changes in gas ambients between hydrogen and dried air were related to sensor thickness in terms of a grain surface defect diffusion process. This is driven by the equilibrium requirement between the exposed, gas modulated film surface states and inter-grain surface defects which are not subject to direct interaction with the gas ambient, owing to low structural porosity.