Many chemical and physical factors govern the mobility of metal contaminants in soils and clay systems; some of these chemical factors include mineralogical composition, cation exchange capacity, organic matter content, pH and the ionic strength of soil water. This makes understanding and therefore predicting the fate of metal contaminants in soils a complex undertaking. There were two broad objectives in this study. The first was to investigate binary and ternary sorption systems, with the aim to understand the effects that factors such as pH, ionic strength, organic matter and metal concentrations, have on sorption of simple clay minerals (bentonite and kaolinite) with metals (cadmium, caesium, nickel and strontium). The second was to investigate the retention of heavy metals and radionuclides by well characterised organic-rich and organic-poor clay soils, breaking them down to their individual components to help understand the effects of each component separately, the study also tested to see if the additivity principle holds for these heavy metals and radionuclides, the additivity principle presumes that the overall sorption behaviour of a complex mixture is a summation of the weighted individual sorption behaviours of its constituents. The study also determined the relationship between the natural organic matter (NOM) content and cation exchange capacity (CEC) of the soils and how these affect the mobility of the metals, while also considering the relative importance of the speciation of the metals. Two British clay soils (Mercia Mudstone and London Clay) and two Nigerian soils (an organic-rich Ikeja Loam and the other organic-poor Magodo Laterite) were characterised by X-ray diffraction (XRD) analysis. Batch techniques were employed for the sorption studies, and radiometric techniques, ICP-OES and ICP-MS were used to quantify metal distribution between phases. The sorption of dissolved organic matter to clay minerals is very dependent on pH; this dependence is greater with increasing concentration of organic matter. The formation of metal-humate complexes is dependent on the nature of the metal and pH. Caesium exhibits no discernible sorption to humic acid, cadmium sorption is enhanced by increasing alkalinity but this enhancement is slightly reduced in higher concentrations of humic acid, nickel sorption is mostly unaffected by pH except in higher concentrations of humic acid and enhanced only under very low concentrations of humic acid, while strontium sorption to humic acid is reduced with increasing alkalinity. The nature and preference of humic acid sorption for these metals are vital to understanding the role played by humic acid in the ternary sorption studies of metals, humic acid and clay minerals. Strongly acidic conditions dominate other factors affecting sorption such as ionic strength in sorption of metals to clay minerals. Caesium sorption to bentonite at pH 4 is poor and almost unaffected by ionic strength of the electrolyte solution; saturation of sorption sites is reached with low amounts of adsorbed caesium. Strontium also binds poorly to bentonite at pH 4, more so than caesium, but an ionic strength effect on sorption still exists and is discernible even under these conditions. Increasing alkalinity has the expected effect of increasing sorption capacity of bentonite for both metals. Bentonite has poor sorption properties, having low affinity for caesium and strontium, but has greater affinity for caesium than strontium. The presence of humic acid can enhance or suppresses sorption, this varies from metal to metal and from solid to solid, the degree of enhancement or suppression also depends on humic acid concentration. Kaolinite has better sorption properties than bentonie. Cadmium has greater sorption affinity for kaolinite in the absence of humic acid, but nickel sorption is more enhanced in the presence of humic acid. Although the presence of humic acid enhances cadmium and nickel sorption to kaolinite, low humic acid concentration provides the best conditions for maximum sorption of both metals. High concentrations of humic acid lead to colloid formation which block access of metals with larger hydration radii to sorption sites while also encouraging the formation of humic acid-metal complexes. As with bentonite, caesium and strontium are both poorly sorbed by kaolinite. Unlike with cadmium and nickel however, the enhancement of strontium sorption is supported by higher concentrations of humic acid, these confirm a greater preference for the formation of S-HA-Sr ternary and lower preference for the formation HA-Sr binary complexes. The presence of humic acid inhibits caesium binding, and retention but this reduces with increasing alkalinity, while the reverse is the case with strontium whose retention is very poor and improved in the presence of humic acid and increasing alkalinity. Both caesium and strontium are poorly sorbed and retained by kaolinite but their retention improves with increasing humic acid concentration and pH. Cadmium and nickel also exhibit poor retention to kaolinite but their retentions are more improved under alkaline conditions and higher humic acid concentrations, nickel more so than cadmium. Similar sorption affinities were exhibited by the British (London Clay and Mercia Mudstone) and Nigerian soils (Magodo Laterite and Ikeja Loam) for the metals studied, showing the significance of soil constituent contribution to sorption behaviour. Both British clay matrices have affinity for the metals in the order Cs >> Cd ≈ Ni >> Sr, London Clay has the greater sorption capacity for all the metals, the clay mineral content of Mercia Mudstone is almost entirely made up of Illite while London Clay contains a mixture of smectite, illite and kaolinite with smectite being the most prevalent clay mineral phase. These confirm that smectite-rich clay systems will exhibit better sorption and retention capacities for metal contaminants. Both Nigerian soils showed the same order of affinity for all the metals Cd >> Ni >> Cs >> Sr, cadmium s preferential sorption to kaolinite was observed in its greater sorption and retention by the Nigerian soils which are kaolinite-rich. This preferential sorption of cadmium by kaolinite is confirmed by the Standard Addition experiment where its contribution to cadmium sorption is clearly evident, a trend not replicated with nickel as the sorbing metal. The presence of organic matter in soils or clay systems improves their metal sorption capacity significantly, especially true for insoluble organic matter, however its significance is reduced as pH increases. The contribution of organic matter also depends on the sorption affinity of the metal for organic matter; metals such like strontium are more affected by organic matter presence. The overall sorption behaviour of complex systems such as soils is difficult to attribute to their individual constituents. The laterite soils can be considered a relatively simple soil system containing only four constituents in significant quantities, yet it is difficult to replicate its sorption behaviour using a replicate proportioned mixture of its constituent phases. The additively calculated sorption profiles for the synthetic laterite were different from those obtained experimentally, the reason for this is that the existence of significant particle size differences between the natural and synthetic soils give rise to differences in the availability of sorption sites which is evident from the different CEC values measured for both systems.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Master of Science / Food Science and Industry / Fadi M. Aramouni / Gluten-free products are becoming more prevalent in the market today, however there are a few types of products that have “hidden” gluten and people will not realize until after consumption. Products like soy sauce and beer are sources of gluten that people don’t know about. Soy sauce contains wheat as a main ingredient so replacing it with a gluten-free flour such as sorghum may produce a product similar to wheat-based soy sauce. Sorghum was used in this experiment since it is a grain grown in the mid-western region of the United States and a growing food ingredient in the global market. Sorghum can come in many different varieties and colors so we used different varieties in this study. Four treatments were done using three different sorghum flours (black, white, and waxy sorghum flour) and a wheat flour for a control. Cooked soybeans were mashed in a kitchenaid mixer and the treatment flour was added to make a dough. That dough was formed into a log and cut into slices. The slices were then staked with wet paper towels to mold. After 13 days of molding, the slices that were made were dried, placed in a salt solution, and fermented for 100 days. The solution was mixed with a spatula for 30 seconds to homogenize the mixture every 2-3 days and samples were taken every 10 days to test for pH, salinity, and color. Once the 100 days were complete and the pH of each treatment did not drop for consecutive testing periods, the liquid was removed from the solids and pasteurized. The pH curve did show that a fermentation process did occur, however there was no control over what microorganism could grow. Consumer testing was not performed since all test sauces were deemed unacceptable at the initial screening.

Master of Science / Department of Biomedical Sciences / Warren Beard / Reasons for performing study: Caecal acidosis is a central event in the metabolic cascade that occurs following grain overload. Buffering the caecal acidosis by enterally administered sodium bicarbonate may be beneficial to affected horses. Objectives: To determine the effect and duration of enterally administered sodium bicarbonate (NaHCO[subscript]3) on caecal pH in healthy horses. Study design: Prospective controlled study using normal horses with caecal cannulas Methods: 9 horses previously fitted with a caecal cannula. 6 horses received 1.0 g/kg bwt NaHCO[subscript]3 via nasogastric tube and 3 control horses were given 3 L of water via nasogastric tube. Clinical parameters, water consumption, venous blood gases, caecal pH, faecal pH and faecal water content were measured at 6 hour intervals over a 36 hour study period. Results: Horses that received enterally administered NaHCO[subscript]3 had a significantly increased caecal pH that lasted the duration of the study. Treated horses increased their water intake, developed metabolic alcalemia, significantly increased sodium concentrations and significantly decreased potassium concentrations. Conclusions and potential relevance: Enterally administered NaHCO[subscript]3 may be beneficial in buffering the caecal acidosis that occurs following an acute carbohydrate overload

O presente trabalho visou basicamente estudar a influência dos fatores ph, temperatura de ativação e tempo de incubação na germinação dos esporos de bactérias isoladas da fermentação alcoólica. Para ativação, os esporos de Bacillus subtilis, Bacillus coagulans, <Bacillus brevis e Bacillus megaterium foram submetidos aos aquecimentos a 60, 80 e 90 ºC em caldo de cana-de-açúcar a ph 4,5; 5,5 e 6,5. Depois do tratamento de ativação, as suspensões de esporos foram resfriadas à aproximadamente 35ºC, e em seguida, pré-incubadas a 35,0 &#177; 1,0 ºC por 6 horas. Amostras foram coletadas a 0, 2, 4 e 6 horas, diluídas serialmente, plaquadas e incubadas a 35,0 &#177; 1,0 ºC por 24 horas. O número de colônias foi tomado como o número de esporos ativados e germinados. A análise estatística dos dados permite concluir que houve uma diminuição no número de esporos germinados, para todas as espécies de Bacillus empregadas, com o aumento da temperatura e tempo de incubação, sendo que a ativação a 90 ºC provocou uma certa inativação dos mesmos. Houve também redução no número de esporos germinados para todos os níveis de ph, com o aumento do tempo de incubação, e o ph 4,5 mostrou um efeito inibitório mais acentuado na germinação dos esporos, exceto para Bacillus brevis. De uma maneira geral, verificou-se que o melhor tratamento para a ativação e germinação dos esporos das quatro espécies investigadas, em meio de caldo de cana-de-açúcar foi 80 ºC e ph 5,5. / This study was undertaken to investigate the influence of pH, activation temperature and incubation time on germination of bacteria spores isolated from alcohol fermentation process. The spores of Bacillus subtilis, Bacillus coagulans, Bacillus brevis and Bacillus megaterium were activated by heating them at 60, 80 and 90 ºC in sugar- cane- juice at pH 4,5, 5,5 and 6,5. After the activation treatments the spores suspensions were cooled to 35,0 ºC and then pre-incubated at 35,0 &#177; 1,0 ºC for 6 hours. Samples were withdrawn at 0, 2, 4 and 6 hours, serial diluited plated and incubated at 35,0 &#177; 1,0 ºC for 24 hours. The number of colonies developed was taken as the number of spores activated and germinated. The statiscal analysis of data showed that there was a reduction of the number of spores germinated for all four species of Bacillus, as the temperature of activation and time of incubation increased. The higher activation temperature (90 ºC) showed and inactivation effect on the spores. There was also a reduction of the spores germinated for all pH levels with the increase of the incubation time, and pH 4,5 showed a higher inhibitory effect on the spore germination, with exception for B. brevis spores. In the overall, the best treatments for the spores activation and germination in sugar-cane-juice, was 80 ºC and pH 5,5, what means that they may germinated if present, in the sugar-cane-juice, at the heat treatment conditions, for a sugar and alcohol production.

O cádmio (Cd) é um metal pesado e dos mais abundantes elementos encontrados no ambiente. Existem evidências de sua relação coma osteopenia, osteoporose, e osteomalacia e fragilidade do tecido ósseo. Este estudo visa avaliar o efeito do pH da água de beber na gênese da alteração óssea provocada pela intoxicação por cádmio. Neste estudo, foram utilizados90 ratosWistar (Ratus Norvegicus albinus), adultos, machos,divididos em 6 grupos, aos quais foram administrados: A -solução de cloreto de Cd(400mg/L) com pH neutro (pH 7,0); B -solução de cloreto de Cd(400mg/L) com pH ácido (pH 5,0); C -solução de cloreto de Cd(400mg/L) com pH básico (pH 8,0). D -pH ácido (pH 5,0); E -pH básico (pH 8,0); F -pH neutro (pH 7,0). Nofêmur esquerdo de cada rato avaliou-se a densidade óssea, por meio do densitômetro de dupla emissão (DEXA), ensaiosbiomecânicos e escala de HU na tomografia computadorizada espiral.Os resultados demostram que a densidade óssea reduziunos grupos que receberam cádmio e no grupo sem administração de cádmio para o pH 5 ocorreu uma redução da densidade mineral óssea (DMO) e do conteúdo mineral ósseo (CMO). A rigidez biomecânica mostrou-se aumentada para o grupocom pH 5 sem cádmio. Como conclusão geral o cádmio reduziu a densidade óssea. / The cadmium (Cd) is a heavy metal, one of the most abundant elements found in the environment. There are evidences of its relationship in osteopenia, osteoporosis e osteomalacia and fragility of the bone tissue. This study aims to evaluatethe effect of the pH of the drinking water in the bonealteration origin caused by cadmium intoxication. This study envolved90 wistar rats (Ratus Norvegicus albinus), adults, males,divided in 6groups, were witch one receved: A -cadmium choride solution (400mg/L)withneutral ph (pH 7,0); B -cadmium choride solution(400mg/L) with acid ph (pH 5,0); C -cadmium choride solution(400mg/L)with basic ph(pH 8,0); D -with acid ph (pH 5,0); E -basic ph (pH 8,0); F -neutral pH (pH 7,0).Left femurs from each rat were evaluatedbybone density,DEXA,biomechanictest,HU scale from computerized tomography. The results shows that bone density became lower in the groups that received cadmium. In that wich received no cadmium with pH 5 ocurred an lower level of bone mineral density (BMO) andbone mineral content (BMC).The bone rigidity proved increased in the pH 5 with no cadmium. As a general conclusion, cadmium reduced the bone density.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Horticulture in the Faculty of Applied Sciences at the Cape Peninsula University of Technology 2013 / This study evaluated the effects of different pH levels and supplementary phosphorous concentrations on Salvia chamelaeagnea grown in hydroponics. The treatments consisted of 12 treatments of 4 differing nutrient solutions offering: low concentration of supplementary P (control), balanced concentration of supplementary P, moderate concentration of supplementary P and a high concentration of supplementary P at 3 differing pH levels. Each treatment was replicated 10 times. The objectives of this study were to asses the effect of supplementary phosphorous concentrations and 3 different pH levels on the growth, development and chlorophyll responses of Salvia chamelaeagnea grown hydroponically. Growth and development was recorded by measuring weekly heights, numbers of basal shoots, stem diameters and the number of branches, while root length and wet and dry weights of roots and shoots were measured post harvest. Chlorophyll responses were recorded by measuring weekly SPAD-502 measurements while post harvest DMSO analysis of chlorophyll A, B and total chlorophyll were recorded along with nutrient uptake levels of N, P,K, Ca, Mg, Na, Mn, Fe, Cu, Zn and B in the plant leaves. This study has shown that the use of a hydroponic nutrient system offering a moderate concentration of supplementary P at a pH level of 4 significantly influences the growth and development of Salvia chamelaeagnea grown in hydroponics. Plants treated with a pH level of 4 generally produced higher wet and dry shoot weights, root lengths, stem diameters, basal shoot numbers, branch numbers, and plant heights than that of the control and all treatments delivering nutrients at a pH level of 6 and 8. Although no one treatment offering supplementary P produced consistently high results, in most cases all the plants receiving supplementary P at a pH level of 4 outperformed the pH 6 and pH 8 treatments receiving the same amount of supplementary P. This indicates that at a pH level of 4 the mineral nutrient availability of a nutrient solution is at an adequate level for the growth and development of Salvia chamelaeagnea. Furthering studies into the effects of arbuscular mycorrhiza on the uptake of mineral nutrients, root morphology and growth and development are recommended.

A resistência à corrosão das ligas de alumínio está relacionada ao meio de exposição, composição química, presença de intermetálicos e microestrutura do metal, entre outras. Neste trabalho investigou-se a corrosão nas ligas de alumínio 3105 H16 e 5052 H34, comumente utilizadas na indústria de carrocerias de ônibus, em meio aquoso continham íons agressivos, tais como cloretos, sulfatos e hidroxilas. Avaliou-se comparativamente o comportamento destas ligas com os revestimentos de proteção de Nanocerâmico, Cromo VI, Cromo III e Sistema de Pintura em exposição atmosférica acelerada e imersão em diferentes meios agressivos. Estudos mais aprofundados restringiram-se às ligas sem tratamento, para as quais foram realizados ensaios de exposição acelerada em névoa salina neutra, névoa salina acética, câmara de umidade e exposição atmosférica natural. Microscopia eletrônica de varredura por emissão de campo foi empregada para caracterizar a superfície das ligas antes e após os ensaios de névoa salina neutra e acética. O comportamento eletroquímico das ligas sem tratamento foi determinado através do monitoramento do potencial de circuito aberto, curvas de polarização potenciodinâmica anódicas e espectroscopia de impedância eletroquímica. Os resultados mostraram que o tratamento de Cromo VI foi o que obteve melhor desempenho na proteção de ligas de alumínio, particularmente para a liga 5052. De um modo geral, a liga 5052 apresentou maior resistência à corrosão nos meios testados em presença ou não de tratamentos superficiais. Na exposição à névoa salina, a corrosão manifestou-se principalmente na forma de pites. Ficou comprovado que o efeito do íon Cl- é importante, porém o fator preponderante do comportamento à corrosão das ligas de alumínio está relacionado ao pH do meio de exposição, sendo este recomendado para avaliar revestimentos protetores. Além das condições do meio ao qual o metal será exposto, na seleção de tratamentos anticorrosivos é importante considerar as particularidades de cada liga, uma vez que suas características composicionais e microestruturais exercem relevante influência no desempenho à corrosão. / The corrosion resistance of aluminum alloys is related to the exposure medium, chemical composition, presence of intermetallic particles and metallic microstructure, among others. This work investigated corrosion of 3105 H16 and 5052 H34 aluminum alloys commonly used in the bus body industry in aqueous media containing aggressive ions, such as chlorides, sulfates and hydroxyls. The behavior of these alloys with the protective coatings of Nanoceramic, Chromium VI, Chromium III and Paint System in accelerated atmospheric exposure and immersion in different aggressive media was evaluated comparatively. Further studies were restricted to untreated alloys for which accelerated exposure tests were performed on neutral salt spray, acetic salt spray, moisture chamber and natural atmospheric exposure. Field scanning electron microscopy was used to characterize the alloys surface before and after neutral and acetic salt spray tests. The electrochemical statement of the untreated alloys was determined by monitoring the open circuit potential, anodic potentiodynamic polarization curves and electrochemical impedance spectroscopy. Results have shown that the treatment with Chromium VI was the one that obtained better performance in the protection of the aluminum alloys, particularly for 5052 alloy. In general, 5052 aluminum alloy presented greater resistance to corrosion in all tested media, with or without surface treatments. Under salt spray exposure, the corrosion attack appeared mainly in the form of pitting. It has been proven that the effect of Cl- ion is important, but the predominant factor on the corrosion behavior of aluminum alloys is related to the pH of the exposure medium, which is recommended to evaluate protective coatings. Besides the conditions of the medium to which the metal will be exposed, in the selection of anticorrosive treatments it is important to consider the particularities of each alloy, since its compositional and microstructural characteristics exert a relevant influence on the corrosion performance.

O presente trabalho visou basicamente estudar a influência dos fatores ph, temperatura de ativação e tempo de incubação na germinação dos esporos de bactérias isoladas da fermentação alcoólica. Para ativação, os esporos de Bacillus subtilis, Bacillus coagulans, <Bacillus brevis e Bacillus megaterium foram submetidos aos aquecimentos a 60, 80 e 90 ºC em caldo de cana-de-açúcar a ph 4,5; 5,5 e 6,5. Depois do tratamento de ativação, as suspensões de esporos foram resfriadas à aproximadamente 35ºC, e em seguida, pré-incubadas a 35,0 &#177; 1,0 ºC por 6 horas. Amostras foram coletadas a 0, 2, 4 e 6 horas, diluídas serialmente, plaquadas e incubadas a 35,0 &#177; 1,0 ºC por 24 horas. O número de colônias foi tomado como o número de esporos ativados e germinados. A análise estatística dos dados permite concluir que houve uma diminuição no número de esporos germinados, para todas as espécies de Bacillus empregadas, com o aumento da temperatura e tempo de incubação, sendo que a ativação a 90 ºC provocou uma certa inativação dos mesmos. Houve também redução no número de esporos germinados para todos os níveis de ph, com o aumento do tempo de incubação, e o ph 4,5 mostrou um efeito inibitório mais acentuado na germinação dos esporos, exceto para Bacillus brevis. De uma maneira geral, verificou-se que o melhor tratamento para a ativação e germinação dos esporos das quatro espécies investigadas, em meio de caldo de cana-de-açúcar foi 80 ºC e ph 5,5. / This study was undertaken to investigate the influence of pH, activation temperature and incubation time on germination of bacteria spores isolated from alcohol fermentation process. The spores of Bacillus subtilis, Bacillus coagulans, Bacillus brevis and Bacillus megaterium were activated by heating them at 60, 80 and 90 ºC in sugar- cane- juice at pH 4,5, 5,5 and 6,5. After the activation treatments the spores suspensions were cooled to 35,0 ºC and then pre-incubated at 35,0 &#177; 1,0 ºC for 6 hours. Samples were withdrawn at 0, 2, 4 and 6 hours, serial diluited plated and incubated at 35,0 &#177; 1,0 ºC for 24 hours. The number of colonies developed was taken as the number of spores activated and germinated. The statiscal analysis of data showed that there was a reduction of the number of spores germinated for all four species of Bacillus, as the temperature of activation and time of incubation increased. The higher activation temperature (90 ºC) showed and inactivation effect on the spores. There was also a reduction of the spores germinated for all pH levels with the increase of the incubation time, and pH 4,5 showed a higher inhibitory effect on the spore germination, with exception for B. brevis spores. In the overall, the best treatments for the spores activation and germination in sugar-cane-juice, was 80 ºC and pH 5,5, what means that they may germinated if present, in the sugar-cane-juice, at the heat treatment conditions, for a sugar and alcohol production.