Este trabalho consiste em utilizar a técnica de Espectroscopia de Impedância Eletroquímica (EIE) na investigação da cinética de diferentes materiais eletrocatalíticos. O modelo de eletrodos porosos se apresenta como uma forma bastante promissora no tratamento das respostas em freqüência dos ADEs. Uma vez estabelecida a aplicação do modelo, pode-se chegar à obtenção de informações cinéticas importantes durante a análise de vários fatores que ocorrem no sistema em questão, sendo possível então, confirmar resultados obtidos por outras técnicas. Foram investigados eletrodos do tipo ADEs de composição Ti/Ru0,3Ti(0,7-x)SnxO2 (x = 0; 0,3 e 0,7), investigando o efeito da eletrodeposição de Pt na superfície do ADE de Ti/Ru0,3Ti0,7O2, a fim de comparar os resultados obtidos por EIE (ac) com o estudo cinético realizado por curvas de polarização de Tafel (dc) em meio ácido. Além destes realizou-se a investigação dos ânodos, aplicáveis a células a combustível de etanol (DEFCs), de composição: Ti/Pt, Ti/Pt:Ru (80:20), Ti/Pt:Sn (80:20) e Ti/Pt:Ru:Sn (80:10:10) em meio ácido e também de etanol, utilizando-se a EIE como elemento de diagnóstico da atividade da composição do ânodo. Os resultados de EIE confirmam que, o aumento da concentração de SnO2 na composição dos ADEs, favorece a formação de oxigênio, como o apresentado na literatura, por outras técnicas eletroquímicas. A linha de transmissão de um canal apresentou valores satisfatórios dos seus elementos, coerentes com os valores apresentados na literatura, quanto utilizada a técnica da EIE. Foi observado também que adição de Pt na composição do ADE Ti/Ru0,3Ti0,7O2 melhorou a eficiência do material, apresentando menores valores de resistência à transferência de carga, A resistência de transferência de carga (Rtc) diminui à medida que se aumenta o potencial, no sentido da RDO. Analisando-se aos valores de potencial em função das curvas de polarização de Tafel e EIE, pode-se concluir então que existe um relação entre o comportamento ac e dc do sistema. Nos estudos de materiais aplicados a DEFCs, confirmam os resultados que a introdução de Sn melhora a atividade para a oxidação do etanol. A composição Ti/Pt:Sn(80:20) apresentou os melhores resultados nos testes de EIE, obtendo-se valores menores de resistência a transferência de carga, concordando com os resultados obtidos no estudo de célula a combustível. / This work consists in using Electrochemical Impedance Spectroscopy (EIS) in the research of various electrocatalytic materials. The porous electrode model is a very promising approach to treat the frequency responses of Dimensionally Stable Anodes (DSA®). Once the application of the model is established, it is possible to obtain important kinetic information while various factors occurring in the system are analyzed. This allows confirmation results obtained by other techniques. Electrodes of the DSA® type with composition Ti/Ru 0,3Ti(0,7-x)SnxO2 (x=0; 0,3 e 0,7) were investigated. In order to compare the results obtained for DSA® Ti/Ru 0,3Ti0,7O2 electrodes by EIS (ac) with the kinetic studies by Tafel (dc) polarization curves performed in acid environment. Additionally, an investigation of the anodes, applicable to Direct Oxidation of Ethanol Fuel Cells (DEFCs), with composition Ti/Pt, Ti/Pt:Ru (80:20), Ti/Pt:Sn (80:20) and Ti/Pt:Ru:Sn (80:10:10) in acid environment and also in ethanol was carried out, using EIS as a diagnosis element for the activity of the anode composition. The EIS results confirmed that increasing concentration of SnO2 in the DSA® composition enhances oxygen formation, as reported in the literature, for other electrochemical techniques. The EIS technique revealed that the transmission line of one canal provided satisfactory data for its elements, in agreement with literature data. Pt addition to the DSA® Ti/Ru 0,3Ti0,7O2 improved the material efficiency, giving smaller resistance values for charge transfer. The resistance of the charge transfer (Rtc) lowered with increasing potential, in the direction of RDO. Analysing the potential values as a function of the Tafel polarization curves and EIS, it is possible to conclude that there is a relationship between the ac and dc behaviors of the system. In the studies of materials applicable to DEFCs it was confirmed that Sn improves the activity for ethanol oxidation. The composition Ti/Pt:Sn (80:20) led to the best results in EIS tests, revealing lower resistance values in the charge transfer, in agreement with results obtained in the study of fuel cells.

The currently reported work involved fundamental study of auto-ignition under unusually high knock intensities in an optical spark ignition engine. The single cylinder research engine adopted included full bore overhead optical access capable of withstanding continuous peak in-cylinder pressure and knock intensity of up to 150 bar and 60 bar respectively. Heavy knock was deliberately induced under relatively low loads (5 bar IMEP) using inlet air heating up to 66 °C and a primary reference fuel blend of reduced octane rating (75 RON). High speed chemiluminescence natural light imaging was used together with simultaneous heat release analysis to evaluate the combustion events. The key out comes of this study could be listed as follow: • Proof and improved understanding of multi centred auto-ignition events under high KIs • Improved understanding of the potential pitfalls of over-fuelling for heavy knock suppression • Optical validation of 'natural' oil droplet release and on-off behaviour of knocking cycles Multiple centred auto-ignition events were regularly observed to lead in to violent knocking events, with knock intensities above 140 bar observed. The ability to directly image the events associated with such high magnitude of knock is believed to be a world first in a full bore optical engine. The multiple centred events were in good agreement with the developing detonation theory to be the key mechanism leading to heavy knock in modern downsized SI engines. The accompanying thermodynamic analysis indicated lack of relation between knock intensity and the remaining unburned mass fraction burned at the onset of the auto-ignition. Spatial analysis of the full series of images captured demonstrated random location of the first captured auto-ignition sites during developing auto-ignition events. Under such circumstances new flame kernels formed at these sites, with initial steady growth sometimes observed to suppress the growth of the earlier spark initiated main flame front prior to violent end gas auto-ignition. It was found that pre-ignition most commonly initiated in the area surrounding the exhaust valve head and resulted in a deflagration that caused the overall combustion phasing to be over advanced. In the cycles after heavy knock, droplets of what appeared to be lubricant were sometimes observed moving within the main charge and causing pre-ignition. These released lubricant droplets were found to survive within the combustion chamber for multiple cycles and were associated with a corresponding "on-off" knocking combustion pattern that has been so widely associated with super-knock in real downsized spark ignition engines. This research also concerned with improving understanding of the competing effects of latent heat of vaporization and auto-ignition delay times of different ethanol blended fuels during heaving knocking combustion. Under normal operation the engine was operated under port fuel injection with a stoichiometric air-fuel mixture. Additional excess fuel of varied blend was then introduced directly into the end-gas in short transient bursts. As the mass of excess fuel was progressively increased a trade-off was apparent, with knock intensity first increasing by up to 60% before lower unburned gas temperatures suppressed knock under extremely rich conditions (γ=0.66). This trade-off is not usually observed during conventional low intensity knock suppression via over-fuelling and has been associated with the reducing auto-ignition delay times outweighing the influence of charge cooling and ratio of specific heats. Ethanol had the highest latent heat of vaporization amongst the other fuels directly injected and was more effective to reduce knock intensity albeit still aggravating knock under slightly rich conditions. Overall, the results demonstrate the risks in employing excess fuel to suppress knock deep within a heavy knocking combustion regime (potentially including a Super-Knock regime).

Alcoholism is a devastating chronic relapsing disorder with significant costs to individuals and society. The mesolimbic dopamine (DA) system plays an important role in regulating reward and addiction. GABA neurons located in the ventral tegmental area (VTA) regulate VTA DA neuron activity, and are a relevant target for alcohol in the brain. VTA GABA neurons exhibit marked hyperexcitability during withdrawal from ethanol. Past research has demonstrated that the motivational effects of opiates cause a change in VTA GABA(A) receptors in opiate-dependent animals, which switch from a GABA-induced hyperpolarization of GABA neurons to a GABA-induced depolarization. The focus of this study was to characterize excitatory and inhibitory synaptic activity in VTA GABA neurons during withdrawal from acute and chronic alcohol, and to evaluate the function of the GABA(A) receptor in the pathway to dependence. Animals were either given injections of ethanol or saline, or were kept in ethanol vapor or air chambers for three weeks. We used standard whole-cell, perforated patch, and cell-attached mode electrophysiological techniques and pharmacology to obtain recordings of cellular activity. Results for excitatory and inhibitory synaptic events were somewhat mixed and inconclusive. There is evidence for a shift in function of the GABA(A) receptor after exposure to ethanol. We found that after a single injection of ethanol (4.0 g/kg) or a chronic intermittent ethanol vapor exposure, VTA GABA neuron firing rate is less sensitive to muscimol's inhibitory effects. The neural substrates of addiction studied here are important steps in the road to alcohol dependence, and a better understanding of them may lead to novel therapies.

The pharmacokinetics of ethanol and (-)-trans-isomer of 9-tetrahydrocannabinol (THC), and the pharmacokinetic interaction between them were characterized using statistical models in this thesis. In chapter II, a semi-mechanistic absorption rate dependent hepatic extraction model was developed to characterize ethanol pharmacokinetics. The statistical analysis conducted based on this model indicated no association between ethanol disposition and subject age or sex, and a 23% higher typical Vmax value, a 12.5% lower typical Km value for heavy drinkers compared with moderate drinkers. In chapter III, a parent-metabolite pharmacokinetic model was developed to simultaneously describe the concentration time profile of THC and its active metabolite 11-OH-THC. A parent-metabolite model with 3-compartment pharmacokinetic model for THC and a 2-compartment model for 11-OH-THC was found to best describe the pharmacokinetics of THC and 11-OH-THC simultaneously. In chapter IV, the pharmacokinetic interactions of ethanol on THC, 11-OH-THC and 11-nor-COOH-THC were evaluated using linear mixed effects models. The results suggested that co-administration of ethanol caused an increase in THC and 11-OH-THC systemic exposure, failed to influence the terminal elimination processes of THC and 11-OH-THC, and did not affect the pharmacokinetics of 11-nor-9-COOH-THC.

<p>This essay is written within my education for Technical Officer in the Swedish armed forces. The essay describes the alternative fuels that the Swedish armed forces can make use of if the supply of fossil fuels is insecure. The alternative fuels that are described and compared are; Synthetic diesel, Organic diesel, Methanol and Ethanol. The essay describes the process of producing the alternatives, the need for modification and the economics for each alternative. The alternatives are compared and assessed for their ability to secure the supply of fuel to the Swedish Armed Forces. The result of the study is that, while synthetic diesel has the best chemical constitution but is not produced in Sweden, the best alternative fuel for the Swedish armed forces at this moment is organic diesel.</p>

Canola meal was used as an adsorbent in a pressure swing adsorption (PSA) apparatus for ethanol dehydration. The experiments were conducted at different pressures, temperatures, vapor superficial velocities, vapor concentrations and particle sizes. Adsorption experiments were performed at equilibrium and breakthrough points. The results demonstrated that canola meal can break the azeotropic point 95.6 wt% and produce over 99 wt% ethanol. At elevated temperature, feed water concentration, and vapor superficial velocity, it was found that the mass transfer rate increased. In addition, the mass transfer rate decreases when either the total pressure or the size of the adsorbent particles are increased. Breakthrough curves were simulated and the overall mass transfer resistance was evaluated at all experimental runs. The internal mass transfer resistance was identified as the relevant mass transfer mechanism. For canola meal, the equilibrium water/ethanol uptake was achieved at 100, 105, and 110˚C. The Frenkel-Halsey-Hill (FHH) and Guggenheim-Andrson-de-Boer (GAB) models perfectly simulated the water adsorption isotherms. By applying Dubinin-Polanyi model to the experimental data, canola meal was identified as a large pore (non-porous) material. The heat of adsorption on canola meal with particle size of 0.43-1.18 mm was determined to be -32.11 kJ/mol. The result confirms that the adsorption process is an exothermic phenomenon and is of physical type due to the fact that the value obtained as the heat of adsorption is negative and its magnitude is within the range 20–80 kJ/mol. The equilibrium water uptake on canola meal was similar to that reported for other starchy and cellulosic adsorbents, while the ethanol uptake was higher. Water saturated canola meal was successfully regenerated by passing nitrogen at 110˚C which is lower than that for molecular sieves commonly used in industry for bioethanol dehydration. The canola meal bio-adsorbent was re-used for more than 32 cycles and no significant change in adsorption capacity was observed.

<p>The purpose of this work was to design and to develop a high performance catalyst for the production of hydrogen from reforming of crude ethanol and also, to develop the kinetics and reactor model of crude ethanol reforming process. Crude ethanol reforming is an endothermic reaction of ethanol and other oxygenated hydrocarbons such as (lactic acid, glycerol and maltose) with water present in fermentation broth to produce hydrogen (H2) and carbon dioxide (CO2). Ni/Al2O3 catalysts were prepared using different preparation methods such as coprecipitation, precipitation and impregnation methods with different Ni loadings of 10 25 wt.%, 10-20 wt.%, and 10-20 wt.% respectively.</p><p>All catalysts were characterised by thermogravimetric/differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), (including X-ray line broadening), temperature programmed reduction (TPR), BET surface area measurements, pore volume and pore size distribution analysis. TG/DSC analyses for the uncalcined catalysts showed the catalyst were stable up from 600oC. XRD analyses showed the presence of NiO, NiAl2O4 and Al2O3 species on the calcined catalysts whereas Ni, NiAl2O4, and Al2O3 were present on reduced catalysts. BET surface area decreased and average pore diameter reached a maximum and then decreased as the Ni loading increased. The temperature programmed reduction profiles showed peaks corresponding to the reduction of NiO between 400-600oC and reduction of NiAl2O4 between 700-800oC. Catalyst screening was performed in a micro reactor with calcination temperature, reaction temperature and the ratio of catalyst weight to crude ethanol flow rate (W/Fcrude-C2H5OH) of 600 oC, 400oC and 0.59 h respectively. Maximum crude-ethanol conversion of 85 mol% was observed for catalyst with 15wt% Ni loading prepared by precipitation method (PT15), while maximum hydrogen yield (= 4.33 moles H2 / mol crude-ethanol feed) was observed for catalyst with 15wt% Ni loading prepared by coprecipitation (CP15). </p><p>Performance tests were carried out on (CP15) in which variables such as space velocity (WHSV) 1.68h-1to 4.68h-1, reduction temperature 400 to 600oC and reaction temperature 320 to 520 oC, were changed for optimum performance evaluation of the selected catalyst. The catalyst deactivated over first three hours of 11 hours time-on-stream (TOS) before it stabilized, the reaction conditions resulted in a drop of ethanol conversion from 80 to 70mol%.</p><p>The compounds identified in the liqiud products in all cases were ethanoic acid, butanoic acid, butanal, propanone, propanoic acid, propylene glycol and butanedioic acid. The kinetic analysis was carried out for the rate data obtained for the reforming of crude ethanol reaction that produced only hydrogen and carbon dioxide. These data were fitted to the power law model and Eldey Rideal models for the entire temperature range of 320-520 oC. The activation energy found were 4405 and 4428 kJ/kmol respectively. Also the simulation of reactor model showed that irrespective of the operating temperature, the benefit of an increase in reactor length is limited. It also showed that by neglecting the axial dispersion term in the model the crude ethanol conversion is under predicted. In addition the beneficial effects of W/FAO start to diminish as its value increases (i.e. at lower flow rates).

A crucial question in drug addiction research concerns whether the varying reports of dopamine-independent and dopamine-dependent motivation can be integrated. According to one theory, the prior drug history of a subject — that is to say, whether they have received minimal or chronic drug exposure — determines whether opiate motivation is dependent upon the brainstem tegmental pedunculopontine nucleus (TPP) or dopamine neurotransmission. The biological analogue of this change is thought to be a switch in the signalling properties (from hyperpolarizing to depolarizing) of ventral tegmental area (VTA) gamma-aminobutyric acid subtype-A (GABAA) receptors. In this thesis, I demonstrate that the mechanisms underlying opiate motivation can be selected artificially by manipulating the signalling properties of VTA GABAA receptors, irrespective of the past drug history of the subject. Furthermore, I suggest that these same VTA GABAA receptors also play a similar role in controlling ethanol motivation. Indeed, the mechanisms underlying ethanol motivation can be doubly dissociated in a manner similar to that observed with opiates. However, whereas opiate motivation is TPP-dependent in the drug-naive state, I found that ethanol motivation was dependent on dopamine neurotransmission (via the D2 receptor) in drug-naive animals. Conversely, ethanol motivation was TPP-dependent in ethanol-deprived mice (as opposed to opiate motivation being dopamine-dependent in opiate-deprived animals). These effects are consistent with a VTA GABAA receptor switching mechanism identical to the one seen in the case of opiate motivation.

Anaerobic digestion (AD) is a biochemical process consisting of the microbiological conversion of organic materials for the purpose of generating biogas. Biogas is typically composed of 50 to 70% methane (CH4) and 50 to 30% carbon dioxide (CO2) with trace amounts of other compounds. Anaerobic digestion technology is a bioprocessing technology that has the potential to be integrated into an ethanol facility to further capture energy, in the form of methane gas, for use in a combined heat and power (CHP) generator or for integration into the natural gas pipeline grid after undergoing an upgrading process. The most simplistic design of an AD system is the solid state digester (SSD) which is able to process very high solids content materials (greater than 15% solids). A SSD has the potential to be utilized as a manure management system in a beef cattle feedlot and it has the potential to integrate seamlessly into a combined ethanol- feedlot operation to capitalize on the eco-cluster concept in bioenergy production. This thesis investigates the biogas and digestate composition seen from four material blends in a solid-state digester (SSD) system operated as a batch reactor. Wet distiller grains (WDG) from a grain ethanol process and cattle manure were the substrates investigated. To assess the biogas composition the system was operated over a period of time to achieve a quasi steady state within the microbial population to maximize the CH4 concentration in the biogas composition. To assess the robustness of the microbial population within each substrate blend, the biogas concentrations were measured over three cycle periods where a portion of the used substrate was replaced with an equal amount of fresh substrate. The digestate composition was analyzed at the end of each of the cycles and compared with the raw substrate to determine changes in solids and nutrient values. The biogas production calculated in this study determined 0.17, 0.21, 0.18, and 0.12L per gram (VS) within 100% WDG, 75%WDG and 25% manure, 25% WDG and 75% manure and the 100% manure substrate (Group 1 through 4) respectively, averaged over all three digestion cycles. At the end of three cycles of digestion the biogas within the substrate blend containing 25% WDG and 75% manure (Group 3) achieved a measured CH4 concentration of 49% and the biogas within the 100% manure substrate (Group 4) achieved a 59% concentration of CH4. The duration for each of Group 3 and Group 4 to achieve the production of viable biogas was 100 and 90 days of operation respectively. Thus it can be concluded that a SSD system start up duration will be between three and four months in duration. The gas data gathered in this research study indicates Group 3 had the most robust methanogenic culture established as it has the lowest overall N2 and CO2 concentration detected in the biogas, and the most consistent performance of CH4 production during each cycle. The investigation conducted on the nutrient data gathered in this research supports the conclusion drawn from the gas data regarding the overall methanogenic performance of the substrate blends. The nutrient data for Group 3 maintained an average carbon to nitrogen (C:N) ratio of 25:1 over all three digestion cycles. The nitrogen, phosphorous, potassium, and sulphur components of the manure fertilizer value were maintained through the digestion process of this investigation thus typical manure application rate calculations are applicable when field applying digestate.

Anaerobic digestion (AD) is a biochemical process consisting of the microbiological conversion of organic materials for the purpose of generating biogas. Biogas is typically composed of 50 to 70% methane (CH4) and 50 to 30% carbon dioxide (CO2) with trace amounts of other compounds. Anaerobic digestion technology is a bioprocessing technology that has the potential to be integrated into an ethanol facility to further capture energy, in the form of methane gas, for use in a combined heat and power (CHP) generator or for integration into the natural gas pipeline grid after undergoing an upgrading process. The most simplistic design of an AD system is the solid state digester (SSD) which is able to process very high solids content materials (greater than 15% solids). A SSD has the potential to be utilized as a manure management system in a beef cattle feedlot and it has the potential to integrate seamlessly into a combined ethanol- feedlot operation to capitalize on the eco-cluster concept in bioenergy production. This thesis investigates the biogas and digestate composition seen from four material blends in a solid-state digester (SSD) system operated as a batch reactor. Wet distiller grains (WDG) from a grain ethanol process and cattle manure were the substrates investigated. To assess the biogas composition the system was operated over a period of time to achieve a quasi steady state within the microbial population to maximize the CH4 concentration in the biogas composition. To assess the robustness of the microbial population within each substrate blend, the biogas concentrations were measured over three cycle periods where a portion of the used substrate was replaced with an equal amount of fresh substrate. The digestate composition was analyzed at the end of each of the cycles and compared with the raw substrate to determine changes in solids and nutrient values. The biogas production calculated in this study determined 0.17, 0.21, 0.18, and 0.12L per gram (VS) within 100% WDG, 75%WDG and 25% manure, 25% WDG and 75% manure and the 100% manure substrate (Group 1 through 4) respectively, averaged over all three digestion cycles. At the end of three cycles of digestion the biogas within the substrate blend containing 25% WDG and 75% manure (Group 3) achieved a measured CH4 concentration of 49% and the biogas within the 100% manure substrate (Group 4) achieved a 59% concentration of CH4. The duration for each of Group 3 and Group 4 to achieve the production of viable biogas was 100 and 90 days of operation respectively. Thus it can be concluded that a SSD system start up duration will be between three and four months in duration. The gas data gathered in this research study indicates Group 3 had the most robust methanogenic culture established as it has the lowest overall N2 and CO2 concentration detected in the biogas, and the most consistent performance of CH4 production during each cycle. The investigation conducted on the nutrient data gathered in this research supports the conclusion drawn from the gas data regarding the overall methanogenic performance of the substrate blends. The nutrient data for Group 3 maintained an average carbon to nitrogen (C:N) ratio of 25:1 over all three digestion cycles. The nitrogen, phosphorous, potassium, and sulphur components of the manure fertilizer value were maintained through the digestion process of this investigation thus typical manure application rate calculations are applicable when field applying digestate.