Proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) are attractive power sources as they offer high conversion efficiencies with low or no pollution. However, the most commonly used platinum electrocatalyst is expensive and the world supply of Pt is limited. In addition, the slow oxygen reduction and methanol oxidation kinetics as well as the poisoning of the Pt catalyst at the cathode resulting from methanol permeation from the anode through the Nafion membrane to the cathode lead to significant performance loss. Also, the electrocatalyst utilization in the electrodes also needs to be improved to reduce the overall cost of the electrocatalysts and improve the fuel cell performance. This dissertation explores nanostructured Pt alloys with lower cost and higher catalytic activity than Pt for oxygen reduction in PEMFC to understand the effect of synthesis and structure on the catalytic activity, methanol tolerant Pt/TiOx nanocomposites for oxygen reduction in DMFC, nanostructured Pt-Ru alloys for methanol oxidation in DMFC, and improvement in the utilization of Pt by optimizing the membrane-electrode assembly (MEA) fabrication. From a systematic investigation of a series of Pt-M alloys (M = Fe, Co, Ni, and Cu), the catalytic activity of Pt-M alloys is correlated with the extent of atomic ordering. More ordered Pt alloys exhibit higher catalytic activity than disordered Pt alloys. The higher activity of the ordered Pt alloys is found to relate to various factors including the Pt-Pt distance, Pt: 5d orbital vacancy, {100} planar density and surface atomic configuration. The catalytic activity of the Pt alloys is also influenced by the synthesis method. Low temperature solution methods usually result in smaller particle size and higher surface area, while high temperature routes result in larger particle size and lower surface area but with a greater extent of alloying. Pt/TiOx/C nanocomposites exhibit higher performance than Pt for oxygen reduction in DMFC. The nanocomposites show higher electrchochemical surface area, lower charge transfer resistance, and higher methanol tolerance than Pt. Pt-Ru alloy synthesized by a reverse microemulsion method exhibits higher catalytic surface area than the commercial Pt-Ru. The higher catalytic activity is attributed to a better control of the particle size, crystallinity, and microstructure. Membrane-electrode assemblies (MEAs) fabricated by a modified thin film method exhibit much higher electrocatalyst utilization efficiency and performance than the conventional MEAs in PEMFC. Power densities of 715 and 610 mW/cm2 are obtained at a Pt loading of, respectively, 0.1 and 0.05 mg/cm2 and 90 oC. The higher electrocatalyst utilization is attributed to the thin catalyst layer and a better continuity of the membrane/catalysts layer interface compared to that in the conventional MEAs. / text

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This thesis describes the activation of small molecules using frustrated Lewis pairs, in particular investigating their use to reduce CO₂ to methanol, thus producing a new route towards a renewable fuel. Chapter One summarises the requirement for a renewable fuel source, the alternative methods currently available and previous research conducted into converting CO₂ to methanol using FLPs and other reducing agents. Chapter Two describes the synthesis of a new family of electron-deficient tris(aryl)boranes, B(C₆F₅)_3-x(C₆Cl₅)_x (x = 1-3), allowing the electronic effects, resulting from the gradual replacement of C₆F₅ with C₆Cl₅ ligands, to be studied. The novel Lewis acids have been fully characterised and their Lewis acidities have been determined using NMR spectroscopy, electrochemistry and DFT studies. Chapter Three discusses the synthesis of nine novel FLPs and their use to successfully split H2. Each borohydride salt has been spectroscopically fully characterised and five of the salts have been characterised using single crystal X-ray diffraction. To determine the exact positions of the H atoms, single crystal neutron diffraction and DFT experiments were carried out on [1-H][H-TMP]. Chapter Four details attempts to use the borohydride salts, synthesised in Chapter Three, to reduce CO₂ to methanol. Each experiment was been fully investigated and their catalytic viability was determined. The X-ray crystal structure of [1-OCHO][H-TMP] is described and each formatoborate and methoxyborate salt were fully characterised. Chapter Five describes experimental procedures and characterisation data.

Size selective reactivity has been observed in pure aluminum cluster anions as a result of Lewis acid and base pairs. Using this a starting point, the goal of this study has been to explore how reactivity is affected with the addition of one or more ligand, which may induce active sites on the surface of the metal clusters. To study this, a theoretical investigation was undertaken on Al13Ix- and Al14Iy- (x=0-2, y=2-4) and their reactivity with methanol. The hypothesis was that iodine can induce a Lewis base site on the opposite side of the cluster, which may enhance reactivity. In results that are consistent with preliminary experimental data, it was found that the Al13Ix- series has a large energy barrier with respect to the cleavage of the O-H bond of methanol. The clusters of the series act as an extremely poor Lewis acids, and as a result, these clusters are relatively inert to methanol etching. On the other hand, the Al14Iy- series has a low barrier and is expected to react rapidly with methanol. The series is found to be most reactive at an aluminum adatom that is bound to an iodine due to the iodine extracting charge from the aluminum cluster creating a strong Lewis acid site.

This thesis focuses on cognitive functions in patients after methanol poisoning. The theoretical part consists of a description of methanol, characteristics of methanol poisoning and its neurological sequelae. Methanol poisoning affects the basal ganglia, therefore we describe them and their role in cognitive processes. The theoretical part also describes a case of mass methanol poisoning in the Czech Republic in 2012-2013. The practical part compares results of a control group and a group of patients poisoned with methanol in cognitive assessment. Results show that the patients after methanol poisoning have significantly lower scores in tasks testing memory and executive functions than the control group.

In the fall of 2012 took place in the Czech Republic, the methanol case - were poisoned and subsequently to the death of many people. According Zakharov (2013, oral communication) is currently the actual number of victims as 58, with the death of the last of methanol poisoning occurred in early December 2013. Methanol was poisoned dozens of people, from those who survived methanol poisoning has many of them probably lifelong consequences - especially disturbances and disorders of the central nervous system. The main objective of this thesis is to describe what has or has Methanol cause effects on patterns of alcohol and behavior related to alcohol use among target groups and to compare any differences in terms of socio-demographic characteristics, the awareness about the issue of methanol and patterns of use (including use of a harmful dependence). For the realization of this investigation was chosen quantitative research. The theoretical part focuses on alcohol (pharmacodynamics, kinetics, effects of alcohol on the human body or patterns of use). I mention the alcohol addiction and treatment options. I also deal with methanol (kinetics, metabolism, toxicity and poisoning), and finally to the specific aspects of mass poisoning with methanol in the Czech Republic. Data were collected from 25 May to...

In an effort to produce the tetrahedrally coordinated, catalytically active zinc center, three families of tris(2-pyridyl)methanol derivatives were synthesized and characterized. Zinc binding studies revealed that the binding behaviors of the ligands depended on the steric and electronic properties of the substituents on the pyridyl rings, as well as the functional group on the tertiary alcohol. A novel tris-pyridyl macrocyclic receptor was synthesized. The receptor possesses both hydrogen bond donors and acceptors. NMR titration experiments revealed that the receptor simultaneously bound both ammonium cation and the counter anion. The counter anion significantly influences the association between the receptor and the ammonium cation. Chiral ditopic macrocycles, which enantioselectively bind chiral ammonium cations, have also been synthesized. Their enantioselective binding properties, as well as the ditopic recognition properties were investigated

Thesis (M. Tech. Engineering: Electrical--Vaal University of Technology) / The air-breathing Direct Methanol Fuel Cell (DMFC) and Zinc Air Fuel Cell (ZAFC)were experimentally studied in a climate chamber in order to investigate the impact of climatic environmental parameters such as varying temperature and relative humidity conditions on their performance. The experimental results presented in the form of polarization curves and discharge characteristic curves indicated that these parameters have a significant effect on the performance of these fuel cells. The results showed that temperature levels below 0ºc are not suitable for the operation of these fuel cells. Instead, it was found that air-breathing DMFC is favored by high temperature conditions while both positive and negative effects were noticed for the air-breathing ZAFC. The results of the varying humidity conditions showed a negative impact on the air-breathing DMFC at a lower temperature level but a performance increase was noticed at a higher temperature level. For air-breathing ZAFC, the effect of humidity on the performance was also found to be influence by the operating temperature. Furthermore, common atmospheric air pollutants such as N20, S02, CO and N02 were experimentally investigated on the air-breathing DMFC and ZAFC. At the concentration of 20 ppm, these air contaminants showed to have a negative effect on the performance of both air-breathing DMFC and ZAFC. For both air-breathing DMFC and ZAFC, performance degradations were found to be irreversible. It is therefore evident from this research that the performance of the air-breathing fuel cell will be affected in an application situated in a highly air-polluted area such as Vaal Triangle or Southern Durban. It is recommended the air-breathing fuel cell design include air filters to counter the day-to-day variations in concentration of air pollutants.

Em face ao aumento do preço de energia e combustíveis fósseis o conceito de biorrefinaria vem sendo foco de atenção das indústrias de celulose e papel. Esse conceito visa a obtenção de co-produtos a partir de um processo industrial pré-estabelecido sendo necessários alguns ajustes e investimentos. A possibilidade de recuperação do metanol contido no licor negro traz ao setor de celulose e papel o conceito de biorrefinaria florestal. O metanol celulósico contido no licor negro de fábricas de celulose e papel é o principal composto orgânico volátil responsável por mais de 90 % das emissões nessas fábricas. De forma semelhante aos compostos reduzidos de enxofre a formação do metanol ocorre durante a polpação alcalina em digestores, mas seu potencial para recuperação é desconhecido. Por isso, este trabalho teve como finalidade quantificar o metanol presente nos licores negros industriais provenientes de processo de polpação kraft convencional. Os licores negros industriais foram cedidos por fábricas brasileiras de celulose e papel. Para a quantificação desse álcool um método analítico foi otimizado e validado. Além disso, realizou-se o estudo de formação do metanol em licor negro durante a polpação alcalina para verificação dos parâmetros que determinam a concentração desse álcool no licor. O método otimizado mostrouse adequado à análise de metanol em licor negro e com potencial para amostras de condensados. A quantidade de metanol determinada em licor negro industrial mostrou-se passível de recuperação e sua formação durante a polpação foi influenciada pela intensidade da deslignificação do processo. / Given the rising price of energy and fossil fuels the concept of bio-refinery has been the focus of attention from the pulp and paper industries. This concept aims to achieve by-products from a pre-established industrial process which requires adjustments and investments. The recoverability of methanol contained in black liquor brings to the pulp and paper business sector the concept of forest bio-refinery. The cellulosic methanol contained in black liquor from pulp and paper mills is the main volatile organic compound responsible for more than 90% of emissions in these processing plants. Similarly to reduced sulfur compounds, the formation of methanol occurs during alkaline pulping in digesters but its potential for recovery is unknown. Therefore, this work aimed at quantifying the methanol present in industrial black liquor from conventional kraft pulping process. The black liquors were provided by Brazilian pulp and paper mills. To quantify this alcohol, an analytical method was optimized and validated. Moreover, we carried out a study on formation of methanol in black liquor during the alkaline pulping to specify the parameters to determine the concentration of this alcohol in the black liquor. The optimized method was adequate for the analysis of methanol in black liquor and showed potential to evaluate samples of condensates. The amount of methanol in black liquor has shown to be able to be recovered and its formation during pulping was influenced by the intensity of the delignification process.

Estudos com a inclusão de glicerina bruta (GB) na alimentação animal vêm demonstrando benefícios quanto ao aporte energético conseguido, entretanto, existe uma variabilidade quanto aos teores de metanol encontrados na GB, nem sempre mensuradas, podendo apresentar riscos. Objetivou-se com este estudo: adaptar, otimizar e validar a metodologia oficial de determinação de metanol (MeOH) em biodiesel \"EN 14110\" para a matriz GB; aplicar o método para análise em amostras de glicerina bruta e avaliar o efeito do metanol na dieta de ruminantes por meio da técnica in vitro de produção de gases (PG). Foi utilizado um cromatógrafo gasoso Shimadzu modelo GC 2014 equipado com um detector de ionização de chamas (FID). Os parâmetros de validação foram linearidade, limite de detecção (LD) e quantificação (LQ), precisão, exatidão e efeito matriz. Foram analisadas duas amostras industriais de GB e uma obtida em laboratório por meio da reação de transesterificação do óleo de pinhão-manso (Jatropha curcas). A técnica semi automática de produção de gases foi utilizada para avaliar níveis crescentes de inclusão de MeOH na dieta via GB em substituição ao milho em grão a 0, 25, 50, 75 e 100%; correspondendo a doses de MeOH de 0, 0,018, 0,035, 0,053 e 0,071 mg, respectivamente. Como controle positivo foi adicionado um tratamento com inclusão de 8,3 mg MeOH puro na dieta controle sem inclusão de GB. As variáveis avaliadas foram produção de gases total (PGT), degradabilidade da matéria orgânica (DMO), eficiência na conversão de metano (CH4 effic) e o fator de partição (FP). As garrafas contendo as dietas foram incubadas a 39ºC por 24h. O método para análise de MeOH apresentou boa linearidade (r2 >= 0,99), e o LD e LQ foram 0,015 e 0,031%, respectivamente. Não foi observado efeito matriz significativo (4,36%). A precisão nas concentrações testadas, 0,05% e 0,5% foi de 2,09% e 2,39%, respectivamente. As concentrações de 0,05%, 0,2% e 0,5% (m/m) apresentaram recuperações de 88%, 95% e 91%, respectivamente. As amostras da indústria apresentaram teores de 0,047 e <LQ, enquanto que a obtida no laboratório apresentou 7,8% de metanol. A partir dos valores obtidos na produção de gases in vitro observou-se que a inclusão de GB contaminada com MeOH aumentou a DMO, PGT e CH4 e reduziu o FP. Conclui-se que o método é adequado para análise de MeOH em GB, com bom potencial para análise na matriz ração, quando otimizado. A GB contaminada com MeOH influencia a fermentação ruminal, sendo necessário mais estudos para elucidar os mecanismos envolvidos / Studies with the inclusion of crude glycerin (CG) in animal feed have demonstrated benefits on the energy intake achieved. However, there is a variation between the levels of methanol found in CG, not always analyzed, but often passed on to producers and may pose risks for using it as animal feed. The objective of this study was to optimize and to validate the official methodology \"EN 14110\" for determining methanol in biodiesel for CG matrix; to apply the method for analysis in commercial samples and samples produced in the laboratory; and to evaluate the effect of methanol in ruminant feed through the in vitro gas production technique (PG). It was used a Shimadzu gas chromatograph model 2014 GC equipped with a flame ionization detector (FID). The validation parameters were linearity, limit of detection (LOD) and quantification (LOQ), precision, accuracy and matrix effect. There were analyzed two industrial\'s samples and a sample obtained in the laboratory by transesterification of the oil from Jatropha curcas. The semi-automatic in vitro gas production technique was used to evaluate the use of MeOH inclusion in the ruminant diet via CG replacing corn grain at 0, 25, 50, 75 and 100%, corresponding to MeOH doses of 0, 0.018, 0.035, 0.053 and 0.071 mg respectively. As a positive control treatment was added with the inclusion of 8.3 mg pure MeOH. The variables evaluated were total gas production (GP), degradability of organic matter (DMO), efficiency in methane conversion (CH4 effic) and the partition factor (PF). The bottles containing the diets were incubated at 39 ° C for 24h. The method showed good linearity (r2 >= 0.99), the LOD and LOQ were 0.015 and 0.031%, respectively. There was no significant matrix effect (4.36%). The accuracy of the concentration tested, 0.05% e 0.5% was 2.09% and 2.39%, respectively. The concentrations 0.05%, 0,2% and 0.5% (w/w) showed recovery level of 88%, 95% e 91% respectively. The industry samples concentrations were 0.047 and <LOQ, while the laboratory one showed 7.8% of methanol. The in vitro gas production showed that the addition of CG increased GP, DMO and CH4 effc and reduced PF. It was concluded that the method is suitable for analysis in CG MeOH, with good potential for analysis of the feed array after optimization. CG contaminated with MeOH influence ruminal fermentation, requiring further studies to elucidate the mechanisms involved