There is a need to develop techniques for conversion of carbon dioxide to other useful products such as methanol, formaldehyde, formic acid, formate, methane, and hydrocarbons. Carbon dioxide can be converted into these products using different methods such as photochemical, electrochemical, thermochemical and hydrogenation by bacteria. Formate is of interest due to its wide industrial applications which include it’s use in direct liquid fuel cells, as an additive in pyrolysis vapors, a precursor for biological fuels, and it is a key intermediate in methanogenesis breaking down complex organic compounds. In this work, conversion of carbon dioxide to formate was accomplished photochemically. The concentration of formate obtained was quantified using ion chromatography. The yield of formate, based on the amount of carbon dioxide in solution, was 1.54%, while the quantum yield was near 2.0%. Detailed studies of the photoreduction process showed that the amount of sensitizer, light intensity and pH affect the amount of formate generated.

The stability of glass is linked to its composition and the atmosphere controls its alteration. The organic pollutants emitted by wooden showcases play a role in the alteration of historic glasses. This study examines the effects of acetic acid, formic acid and formaldehyde on objects from the National Museums of Scotland and on replica glasses aged artificially, all with a soda silicate composition. Composition was determined by electron microprobe and analytical decomposition of the Raman spectra was used to establish correlations between glass structure and composition. This allowed interpretation of the structural variations between bulk and altered glass. The structure of the glasses altered by pollutants is characteristic of an alteration by selective leaching, with transformation of the silicates linked to alkali into silanols, which subsequently underwent condensation reactions to form a more polymerised structure. The SIMS concentration profiles of glass aged in artificial and real atmospheres were used to follow the alteration evolution as a function of time, humidity and pollutant concentration. The water film formed by the humidity at the surface and its acidity control the alteration by leaching of alkali and hydration of the glass. Formaldehyde does not act on the leaching reaction while acids accelerate and amplify it. In mixed polluted atmosphere, formates compounds always predominate in the film even at low formic acid concentration. The humidity and temperature fluctuations in museums maintain the leaching reaction. Knowledge of the harmful effect of organic acid pollutants in the alteration of soda silicate glasses will help improve their conservation.

The concepts of electroneutrality coupling and electron-hopping, which are useful for the incorporation of functional components and transportation of electrons, were applied in this project. Discrete layered structures were fabricated by sequential electropolymerization to modulate the performances of formate biosensors. Different types of layers, with or without enzyme, were successfully grown on the electrode surface. The presence of the enzyme (formate dehydrogenase), co-factor (B-nicotinamide adenine dinucleotide) and an electron mediator in the polypyrrole film was verified by scanning electron microscopy, chronopotentiometry, cyclic voltammetry and amperometric measurements. Monolayer, bilayer and trilayer formate biosensors were successfully fabricated for different analytical purposes. The utilisation of the biosensing membrane for the reliable batch and FIA determination of formate based on a amperometric mode of detection are explored. Electron mediators such as ferrocyanide, Prussian Blue, ferrocene and ferrocene carboxylic acid were incorporated into the polypyrrole film to lower the required applied potential for amperometric sensing and to maintain the conductivity and stability of the polypyrrole backbone. The application of artificial neural networks (ANN) to overcome the problem of reusability and reproducibilty in a nonlinear and complicated dynamic system is also considered. The resulting system was trained with a new neural network based software package, Turbo Neuron, for prediction of the concentration of formate, based on the entire collected data, which contain the history of the detection experiments. The proposed integrated ANN conducting polymer biosensor enables the determination of formate concentration, both online and in real time / Doctor of Philosophy (PhD)

<p>The dose distribution around brachytherapy (BT) sources is characterized by steep dose gradients and an energy spectrum varying rapidly with depth in water around the source. These two properties make experimental verification of the dose distribution difficult, and put high demands on the dosimetry system in use regarding precision, size and energy dependence. The American Association of Physicists in Medicine (AAPM) recommends lithium fluoride (LiF) thermo-luminescence dosimetry (TLD) to be used for verification measurements, as it is the only dosimetry system meeting the requirements, but still the total combined uncertainty in dose-rate determination is as high as 7-9 % (1 σ). Lithium formate is a new dosimetry material that is less energy dependent than LiF, but more sensitive than the most common EPR (electron paramagnetic resonance) dosimetry material, alanine. In order to evaluate lithium formate EPR for BT dosimetry, dosimeters were produced for experimental dose determination around BT source 192Ir. The dosimeters were calibrated against an ionization chamber in a high energy photon beam. Dose to water was determined at 1, 3 and 5 cm radial distance from the source, which was stepped along a straight line in a PMMA phantom. The experiments were performed twice using 4 dosimeters per distance and experiment. Methods to correct for energy dependence were developed and evaluated. The uncertainty in measured dose was estimated. The experimental dose values agreed with the values from the treatment planning system with a maximum deviation of 3.3 %, and an average 1 σ uncertainty of 3 % at 3 and 5 cm and 5 % at 1cm. Uncertainty in radial distance from the source as well as source calibration were the dominating contributions to the total combined uncertainty. Lithium formate EPR has been shown to be a promising alternative to LiF TLD for BT dosimetry.</p>

The dose distribution around brachytherapy (BT) sources is characterized by steep dose gradients and an energy spectrum varying rapidly with depth in water around the source. These two properties make experimental verification of the dose distribution difficult, and put high demands on the dosimetry system in use regarding precision, size and energy dependence. The American Association of Physicists in Medicine (AAPM) recommends lithium fluoride (LiF) thermo-luminescence dosimetry (TLD) to be used for verification measurements, as it is the only dosimetry system meeting the requirements, but still the total combined uncertainty in dose-rate determination is as high as 7-9 % (1 σ). Lithium formate is a new dosimetry material that is less energy dependent than LiF, but more sensitive than the most common EPR (electron paramagnetic resonance) dosimetry material, alanine. In order to evaluate lithium formate EPR for BT dosimetry, dosimeters were produced for experimental dose determination around BT source 192Ir. The dosimeters were calibrated against an ionization chamber in a high energy photon beam. Dose to water was determined at 1, 3 and 5 cm radial distance from the source, which was stepped along a straight line in a PMMA phantom. The experiments were performed twice using 4 dosimeters per distance and experiment. Methods to correct for energy dependence were developed and evaluated. The uncertainty in measured dose was estimated. The experimental dose values agreed with the values from the treatment planning system with a maximum deviation of 3.3 %, and an average 1 σ uncertainty of 3 % at 3 and 5 cm and 5 % at 1cm. Uncertainty in radial distance from the source as well as source calibration were the dominating contributions to the total combined uncertainty. Lithium formate EPR has been shown to be a promising alternative to LiF TLD for BT dosimetry.

Simple Photochemical Reduction of Carbon Dioxide to Formate Ovuokenye Omadoko, Department of Chemistry, East Tennessee State University, Johnson City, Tennessee. There is a need to develop techniques for conversion of carbon dioxide to other useful products such as methanol, formaldehyde, formic acid, formate, methane, and hydrocarbons. Carbon dioxide can be converted into these products using different methods such as photochemical, electrochemical, thermochemical and hydrogenation by bacteria. Formate is of interest due to having wide industrial applications which include use in direct liquid fuel cells (DLFC’s), an additive in pyrolysis vapors, precursor for biological fuels, and is a key intermediate in methanogenesis breaking down complex organic compounds. In this work, conversion of carbon dioxide to formate was accomplished photochemically. The concentration of formate obtained was quantified using ion chromatography. The yield of formate, based on the amount of carbon dioxide in solution, was 1.54%, while the quantum yield near 1.0%. Detailed studies of the photoreduction process showed that amount of sensitizer, light intensity and pH affect the amount of formate generated.

Vortrag UNIX-Stammtisch 05/98

The green production of formic acid and utilization of methanol over heterogeneous catalysis system were investigated in this study. The heterogeneous catalysts are widely used in the chemical industry. They offer high stability and reusability which can enhance the production ability and lower the production cost, it can be considered as the sustainable energy solution for the future. In this work, we demonstrated several different heterogeneous catalysts for sustainable formic acid production and methanol utilization, including the heteropoly acid supported mesoporous silica catalysts and multi-function mixed metal oxide catalysts. Detailed characterizations of the final products were carried out by N2 adsorption and desorption, XRD, HR-TEM, SEM, ICP-OES, XANES, NH3- TPD, Raman spectroscopy, and FTIR to identify the chemical properties and physical properties of the catalysts. We obtained 60 % glycerol conversion and 30 % formic acid selectivity with at least 3 rounds of usages in batch system over PV1Mo/SBA-15-p-DS catalyst. Moreover, the continuous methyl formate production with significantly high formation rate (16.7) has been achieved via our CuMgO-based catalysts, and the best Cu5MgO5 catalyst gives more than 80 % methanol conversion with constant selectivity to methyl formate even after 4 catalytic test (more than 200 h), revealing their potential for industrialization. For the methanol utilization reaction, the methanol homocoupling to form dimethoxymethane (DMM) has been investigated. The redox and acidic properties of catalysts both play a critical role in this reaction and the related to different product. The supported V2O5 catalyst achieves the best catalytic performance (62.1 % conversion and 85.6 % DMM selectivity) with a Ce/Al specific ratio of 1. This research not only provided the efficient catalysts for numerous application with high activity, but also discovered the relation between the catalytic performance and the nature of the materials. These findings might further help the researcher to solve the global environmental and energy issues in the near future.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21132号 / 農博第2258号 / 新制||農||1056(附属図書館) / 学位論文||H30||N5106(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 加納 健司, 教授 小川 順, 教授 三芳 秀人 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

This research was designed to investigate the hydration reaction of fly ash when exposed to water. The effects that calcium nitrate and calcium formate have on the hydration reactions were also examined.