The utilisation of waste process grease (WPG) as feedstock for biodiesel production was investigated in this study. WPG is a lubrication oil used in the metalworking industry and is considered a hazardous waste material. WPG contains vegetable oil and animal fat which are used as base oils in the lubricant formulation. Three different production routes were followed to produce biodiesel using WPG as feedstock. The first production route involved the conventional two-step production process comprising the acid esterification of the free fatty acids, followed by alkaline transesterification. The second production route involved the extraction of free fatty acids in the WPG by means of liquid-liquid extraction and the production of biodiesel from the extracted free fatty acids through acid esterification. The produced biodiesel was purified by means of chromatography. A third process route was the saponification of the WPG using aqueous sodium hydroxide followed by acidulation with hydrochloric acid. The resulting acid oil was purified by means of column chromatography, using a hydrophobic resin as the stationary phase prior to esterification through acid catalysis to produce biodiesel. The crude biodiesel was purified using column chromatography with silica gel as stationary phase. The optimum reaction conditions for the reduction of the free fatty acid content of WPG in route 1 to 0.5% were a methanol to oil ratio of 8:1 and a reaction temperature of 65 °C with a catalyst loading of 4 wt%. Acetonitrile was found to be the most effective extraction solvent for the reduction of sulphur compounds in the free fatty acid feedstock in route 2. A reverse phase chromatographic system with a hydrophobic stationary phase and methanol as the mobile phase was found to be an effective system to reduce the sulphur to below 10 ppm as specified by the SANS 1935 biodiesel standard in route 3. Both the conventional two-step process (route 1) and the liquid-liquid extraction process (route 2) were found not to be suitable for the production of biodiesel from WPG as the sulphur content of the produced biodiesel for routes 1 and 2 was 8 141 ppm and 4 888 ppm, respectively. The sulphur content of the produced biodiesel following route 3 was 9 ppm. The latter approach reduced the sulphur content of the biodiesel to acceptable levels that conform to the SANS 1935 standard to be used in a B10 biodiesel blend. A biodiesel yield of 45%, calculated as the mass of biodiesel produced as a percentage of the total mass of dried WPG used, was achieved with route 3. The biodiesel conformed to most of the specifications in the SANS1935 standard for biodiesel. The presence of a relatively high concentration of saturated fatty acids reflected in the higher cetane number of 74.7, the high cold filter plugging point of +10 and the oxidative stability of > 6 hours. A comparative cost analysis for route 3 indicated that the production cost of biodiesel, compared to the cost of petroleum diesel is marginally higher at the current Brent crude oil price of $102.41 per barrel. The production of biodiesel from WPG will be economically viable once the crude oil price has risen to about $113 per barrel. / Thesis (PhD (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

The utilisation of waste process grease (WPG) as feedstock for biodiesel production was investigated in this study. WPG is a lubrication oil used in the metalworking industry and is considered a hazardous waste material. WPG contains vegetable oil and animal fat which are used as base oils in the lubricant formulation. Three different production routes were followed to produce biodiesel using WPG as feedstock. The first production route involved the conventional two-step production process comprising the acid esterification of the free fatty acids, followed by alkaline transesterification. The second production route involved the extraction of free fatty acids in the WPG by means of liquid-liquid extraction and the production of biodiesel from the extracted free fatty acids through acid esterification. The produced biodiesel was purified by means of chromatography. A third process route was the saponification of the WPG using aqueous sodium hydroxide followed by acidulation with hydrochloric acid. The resulting acid oil was purified by means of column chromatography, using a hydrophobic resin as the stationary phase prior to esterification through acid catalysis to produce biodiesel. The crude biodiesel was purified using column chromatography with silica gel as stationary phase. The optimum reaction conditions for the reduction of the free fatty acid content of WPG in route 1 to 0.5% were a methanol to oil ratio of 8:1 and a reaction temperature of 65 °C with a catalyst loading of 4 wt%. Acetonitrile was found to be the most effective extraction solvent for the reduction of sulphur compounds in the free fatty acid feedstock in route 2. A reverse phase chromatographic system with a hydrophobic stationary phase and methanol as the mobile phase was found to be an effective system to reduce the sulphur to below 10 ppm as specified by the SANS 1935 biodiesel standard in route 3. Both the conventional two-step process (route 1) and the liquid-liquid extraction process (route 2) were found not to be suitable for the production of biodiesel from WPG as the sulphur content of the produced biodiesel for routes 1 and 2 was 8 141 ppm and 4 888 ppm, respectively. The sulphur content of the produced biodiesel following route 3 was 9 ppm. The latter approach reduced the sulphur content of the biodiesel to acceptable levels that conform to the SANS 1935 standard to be used in a B10 biodiesel blend. A biodiesel yield of 45%, calculated as the mass of biodiesel produced as a percentage of the total mass of dried WPG used, was achieved with route 3. The biodiesel conformed to most of the specifications in the SANS1935 standard for biodiesel. The presence of a relatively high concentration of saturated fatty acids reflected in the higher cetane number of 74.7, the high cold filter plugging point of +10 and the oxidative stability of > 6 hours. A comparative cost analysis for route 3 indicated that the production cost of biodiesel, compared to the cost of petroleum diesel is marginally higher at the current Brent crude oil price of $102.41 per barrel. The production of biodiesel from WPG will be economically viable once the crude oil price has risen to about $113 per barrel. / Thesis (PhD (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013.

In the last couple of years there has been a great need for finding alternative, cleaner burning fuel sources. This search has led to the development of various hydrogen technologies. The reason for this is that when burnt, hydrogen gas only forms water and oxygen as products. One of the methods used in the production of hydrogen gas is that of the electrolysis of sulphur dioxide which is facilitated by a sulphur dioxide depolarized electrolyzer. The electrolysis of sulphur dioxide has the advantage of requiring lower cell voltages in the electrolysis process when compared to the electrolysis of water. This type of electrolyzer unfortunately suffers from low hydrogen gas production volumes. It was thought that by linearly increasing the reactions active area of the electrolyzer, the production volumes can be increased. A linearly upscaled 100cm2 cell was designed by using computer aided design software, such as SolidWorks, Cambridge Engineering Selector, EES and ANSYS. The cell was then constructed and tested to determine the effects of linearly upscaling. The results of the 100cm2 cell were compared to the results of a similar 25cm2 cell and results obtained from the literature. The 100cm2 cell exhibited very poor performance when compared to the other cells. The 100cm2 cell showed lower hydrogen production volumes at higher energy inputs than the 25cm2 cell and an 86cm2 stack assembly. It was concluded that creating stack assemblies with cells with smaller active areas would be much more efficient than linearly upscaling the active area of the cells. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.

In the last couple of years there has been a great need for finding alternative, cleaner burning fuel sources. This search has led to the development of various hydrogen technologies. The reason for this is that when burnt, hydrogen gas only forms water and oxygen as products. One of the methods used in the production of hydrogen gas is that of the electrolysis of sulphur dioxide which is facilitated by a sulphur dioxide depolarized electrolyzer. The electrolysis of sulphur dioxide has the advantage of requiring lower cell voltages in the electrolysis process when compared to the electrolysis of water. This type of electrolyzer unfortunately suffers from low hydrogen gas production volumes. It was thought that by linearly increasing the reactions active area of the electrolyzer, the production volumes can be increased. A linearly upscaled 100cm2 cell was designed by using computer aided design software, such as SolidWorks, Cambridge Engineering Selector, EES and ANSYS. The cell was then constructed and tested to determine the effects of linearly upscaling. The results of the 100cm2 cell were compared to the results of a similar 25cm2 cell and results obtained from the literature. The 100cm2 cell exhibited very poor performance when compared to the other cells. The 100cm2 cell showed lower hydrogen production volumes at higher energy inputs than the 25cm2 cell and an 86cm2 stack assembly. It was concluded that creating stack assemblies with cells with smaller active areas would be much more efficient than linearly upscaling the active area of the cells. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.

Air pollution is ranked by the World Health Organisation as one of the top ten contributors to the global burden of disease and injury. Epidemiological studies have shown that exposure to air pollution is associated with cardiorespiratory diseases. However, most of the previous studies have looked at this issue using air pollution data from a single monitoring site or average values from a few monitoring sites in a city. There is increasing concern that the relationships between air pollution and mortality may vary with geographical area, particularly for a big city. This thesis consisted of three interlinked studies that aimed to examine the spatial variation in the relationship between long-term exposure to air pollution and cardiorespiratory mortality in Brisbane, Australia. The first study evaluated the long-term air pollution trends in Brisbane, Australia. Air pollution data used in this study were provided by the Queensland Environmental Protection Agency (QEPA). The data comprised the daily average concentrations of particulate matter less then 10 µm in aerodynamic diameter (PM10), nitrogen dioxide (NO2), ozone (O3) and sulphur dioxide (SO2) between 1 January 1980 and 31 December 2004 in two monitoring sites (i.e. Eagle farm and Rocklea), and in other available monitoring sites between 1 January 1996 and 31 December 2004. Computerised data files of daily mortality between 1 January 1996 and 31 December 2004 in Brisbane city were provided by the Office of Economic and Statistical Research of the Queensland Treasury. Population data and the Socio-Economic Indexes for Areas (SEIFA) data in 2001 were obtained from the Australian Bureau of Statistics (ABS) for each statistical local area (SLA) of the Brisbane city. The long-term air pollution (the daily maximum 1-hour average or daily 24-hour average concentrations of NO2, O3 and PM10) trends were evaluated using a polynomial regression model in two monitoring sites (Eagle Farm and Rocklea) in Brisbane, Australia, between 1980 and 2003. The study found that there were significant up-and-down features for air pollution concentrations in both monitoring sites in Brisbane. Rocklea recorded a substantially higher number of days with concentrations above the relevant daily maximum 1-hour or 24-hour standards than that in Eagle Farm. Additionally, there was a significant spatial variation in air pollution concentrations between these areas. Therefore, the results indicated a need to examine the spatial variation in the relationship between long-term exposure to air pollution and cardiorespiratory mortality in Brisbane. The second study examined the spatial variation of SO2 concentrations and cardiorespiratory mortality in Brisbane between 1999 and 2001. Air pollutant concentrations were estimated using geographical information systems (GIS) techniques at a SLA level. Spatial distribution analysis and a multivariable logistic regression model were employed to investigate the impact of gaseous air pollution on cardiorespiratory mortality after adjusting for potential confounding effects of age, sex, calendar year and SEIFA. The results of this study indicate that for every 1 ppb increase in annual average SO2 concentration, there was an estimated increase of 4.4 % (95 % confidence interval (CI): 1.4 - 7.6 %) and 4.8 % (95 % CI: 2.0 - 7.7 %) in cardiovascular and cardiorespiratory mortality, respectively. We estimated that the excess number of cardiorespiratory deaths attributable to SO2 was 312 (3.4% of total cardiorespiratory deaths) in Brisbane during the study period. Our results suggest that long-term exposure to SO2, even at low levels, is a significant hazard to population health. The final study examined the association of long-term exposure to gaseous air pollution (including NO2, O3 and SO2) with cardiorespiratory mortality in Brisbane, Australia, 1996 - 2004. The pollutant concentrations were estimated using GIS techniques at a SLA level. Logistic regression was used to investigate the impact of NO2, O3 and SO2 on cardiorespiratory mortality after adjusting for potential confounding effects of age, sex, calendar year and SEIFA. The study found that there was an estimated 3.1% (95% CI: 0.4 - 5.8%) and 0.5% (95% CI: -0.03 - 1.3 %) increase in cardiorespiratory mortality for 1 ppb increment in annual average concentration of SO2 and O3, respectively. However there was no significant relationship between NO2 and cardiorespiratory mortality observed in the multiple gaseous pollutants model. The results also indicated that long-term exposure to gaseous air pollutants in Brisbane, even at the levels lower than most cities in the world (especially SO2), were associated with cardiorespiratory mortality. Therefore, spatial patterns of gaseous air pollutants and their impact on health outcomes need to be assessed for an evaluation of long-term effects of air pollution on population health in metropolitan areas. This study examined the relationship between air pollution and health outcomes. GIS and relevant mapping technologies were used to display the spatial patterns of air pollution and cardiorespiratory mortality at a SLA level. The results of this study show that long-term exposure to gaseous air pollution was associated with cardiorespiratory mortality in Brisbane and this association appeared to vary with geographic area. These findings may have important public health implications in the control and prevention of air pollution-related health effects, since now many countries and governments have paid more attention to control wide spread air pollution and to protect our environment and human health.

The oxidative dissolution of chalcopyrite in ferric media often produces incomplete copper recoveries. The incomplete recoveries have been attributed to inhibition caused by the formation of a metal deficient sulphide and the deposition of elemental sulphur and jarosite. Although these phases have been qualitatively identified on the surface of chalcopyrite, none have been quantitatively identified. The aim of the project was to quantitatively analyse the surface before and after oxidative dissolution, with X-ray photoelectron spectroscopy (XPS), and to use the phases identified as the basis for mechanisms of dissolution and inhibition. / XPS analysis was performed on chalcopyrite massive fractured under anaerobic atmosphere and chalcopyrite massive and concentrate oxidised in 0.1 M ferric sulphate (pH 1.9) and 0.2 M ferric chloride (pH 1.6) at 50, 65 and 80ºC. Quantitative XPS analysis of the chalcopyrite surfaces required the development of programs that accounted for the observed XPS spectra. The output of these programs was used to construct profiles of the chalcopyrite surfaces and the deposited phases. These surface profiles were correlated with copper recoveries determined for chalcopyrite concentrate dissolution under the same conditions. / The surface of chalcopyrite before oxidative dissolution reconstructs to form a `pyritic' disulphide phase. This phase is oxidised in ferric media to form thiosulphate via the incorporation of oxygen atoms from the hydration sphere. The thiosulphate reacts in the oxidising conditions of low pH to form elemental sulphur, sulphite and sulphate. The sulphate complexes with ferric to produce hydronium jarosite. This reaction occurs at the surface during the initial stages of dissolution and in the bulk solution during the latter stages. This precipitation of hydronium jarosite during the latter stages of dissolution corresponds to inhibition of the dissolution reaction. It is therefore concluded hydronium jarosite is responsible for inhibiting the oxidative dissolution of chalcopyrite in ferric media. / The identification of hydronium jarosite as the inhibiting phase is consistent with the industrial practice of removing `excess' iron from the ferric solution before oxidative dissolution. However, additional iron and sulphate are generated at the chalcopyrite surface during oxidative dissolution. These high iron and sulphate concentrations combine with the low pH and high temperatures favoured for the oxidative dissolution of chalcopyrite to produce ideal conditions for jarosite precipitation. Therefore, pH must be lowered further to prevent jarosite precipitation and enhance copper recoveries from chalcopyrite in ferric media.

Com o objetivo de avaliar o potencial bioindicador de Psidium guajava e Psidium cattleyanum para avaliação da qualidade do ar em área industrial no município de Canoas, Brasil, estas espécies foram expostas em monitoramento ativo em nove pontos de amostragem, sendo cinco internos e quatro externos a área de influência de uma área industrial e mais um ponto controle localizado no Campus do Vale da Universidade Federal do Rio Grande do Sul, distando 27 Km da área de estudo. Foram realizadas cinco exposições para P. guajava e quatro para P. cattleyanum que coincidiram com as estações de inverno (2005, 2006), primavera (2005), verão (2006) e outono (2006), durante o período de um ano e três meses de monitoramento. A exposição foi feita em estandes padronizados a um metro de altura do solo, com suplementação automática de água e proteção contra o excesso de radiação. Após cada três meses de exposição foram medidos o crescimento relativo em altura, a área foliar e a biomassa total, nas duas espécies expostas.Em P. cattleyanum foi analisado também a formação de ácido malonialdeído (MDA) nas folhas primárias e em P. guajava foi analisado a fotossíntese máxima e a eficiência carboxilativa in vivo, o teor de níquel e de enxofre em folhas secas, previamente lavadas. As medidas de crescimento, área foliar e biomassa não apresentaram diferença significativa em relação ao controle para as duas espécies, o que indica que não houve danos visíveis devido à poluição atmosférica. A formação de MDA mostrou diferença significativa na coleta de verão e inverno, em sua maioria, para os pontos internos. Os teores de enxofre apresentaram valores entre 0,15 e 0,41% ficando abaixo dos níveis basais paraplantas terrestres, observando-se diferenças significativas em relação ao ponto controle, para as coletas de verão e primavera, apenas para dois pontos internos. Os teores de níquel apresentaram valores entre 0,2 e 3 μg g-1, também ficando abaixo dos níveis basais para plantas terrestres, mas apresentaram diferenças significativas em relação ao ponto controle para todas as coletas. Os pontos que apresentaram diferenças para o teor de níquel em relação ao controle foram aqueles localizados internamente na área industrial a menos de 1,5 km da potencial fonte emissora de níquel, excetuando-se a coleta de verão onde a maioria dos pontos apresentou diferenças significativas em relação ao ponto controle. A fotossíntese máxima e a eficiência carboxilativa não apresentaram diferenças significativas em nenhuma coleta. / In order to evaluate the bioindicator potential of Psidium guajava and Psidium cattleyanum to air quality monitoring, these species were exposed in an industrial area in the city of Canoas, Brazil, in ten different sites, five inner, four outside of industrial area and one control site placed at Federal University of Rio Grande do Sul. The exposures coincident with the season of winter (2005, 2006), spring (2005), summer (2006) and fall (2006) amount five exposures for P. guajava, and four exposures for P. cattleyanum. The exposition was made in a standard frame 1,0 m above the ground, with automatic supply of water and protection to excessive radiation. After three moths of exposure it was assessed total biomass, leaf area and height relative growth rate for both species. For P. cattleyanum it was assesed the content of malondialdehyde (MDA) in leaves, and for P. guajava it was assessed the nickel and sulfur content, maximum photosynthesis and carboxilation efficiency.The evaluate of total biomass, leaf area, height relative growth rate did not show any significant differences for both species, that indicate did not occur visual damage due the air pollution. MDA showed significant differences in summer and winter, mostly for inner sites. The sulfur content showed values between 0,15 and 0,41 %, below the basal level for terrestrial plants and showed significant differences in relation of control for spring and summer for three inner sites. The values of Ni showed between 0,2 and 3 μg g-1 and they were below of basal level for terrestrial plants, but showed significant differences in relation to control site for all seasons. The inner sites that showed significant differences were placed about 1,5 km from potential source emission ofNi, except in the summer whose distribution of Ni values was higher and the most of the sites showed significant differences in relation to control site. The maximum photosynthesis and the carboxilation efficiency did not show significant differences in relation to control site.

Large Igneous Provinces (LIPs) form during short-lived pulses of extensive magmatic activity. LIPs are known for their ability to affect global climate as well as for their Ni-Cu-PGE ore potential. A key factor that controls the intensity of the climate impact of a LIP and its ore potential is the assimilation of volatile-rich sedimentary host rocks. Magmas of the High Arctic Large Igneous Province (HALIP), exposed in the Arctic, intruded volatile-rich black shales, carbonates and evaporites in the Canadian Arctic Islands, offering a great opportunity for studying magma-sediment interaction. The purpose of this study is to test whether assimilation of sedimentary sulphide can promote sulphide immiscibility in magma and thus aid formation of Ni-Cu-PGE ore bodies. This is done by analysing sulphur isotopes in pyrite grains hosted in a HALIP dolerite sill, which was emplaced into black shale, by using Secondary Ion Mass Spectrometry (SIMS). Four dolerite samples are analysed; two coming from the lower contact margin of the sill, one from 60 cm into the sill and one sample from a basaltic vein at the upper contact margin of the sill. A total of 14 pyrite grains (n = 246 individual SIMS spot analyses) were analysed for their sulphur isotope ratios. The results of the SIMS analyses show that all analysed sulphides have highly negative δ34S values ranging from -19.5 to -5.7‰ (average δ34S = -8.2 ± 0.83‰, 2SD), which therefore differ largely from that of the primitive mantle (0 ± 1.8‰). In order to put our four analysed dolerite samples into a broader context, δ34S data of our sulphides are compared with whole-rock δ34S and δ18O data from Hare Fiord shale and dolerite samples. The δ34S values of the sulphide samples from the sill typically trend toward the negative sulphur isotope composition of the sulphides in the surrounding shale, and the shale surrounding the sill experiences a loss of 32S near the contact of the sill. This indicates that sedimentary light sulphur (32S) has been locally incorporated into the sill by the surrounding shale, resulting in negative δ34S values in the magmatic sulphides. Since sulphide immiscibility in the Hare Fiord sill was triggered by assimilation of sulphur from host rock shale, the igneous rocks of the HALIP may be prospective for Ni-Cu-PGE mineralization, though more studies are needed. Furthermore, our results suggest that incorporation of crustal sulphur increased the volatile budget of HALIP magmas, which therefore could have contributed to a deterioration of the environmental conditions during the emplacement of the HALIP. / Stora magmatiska provinser (på engelska Large Igneous Provinces, LIPs) är vulkaniska event då enorma mängder magma avsätts över en väldigt stor yta under ett, i ett geologiskt perspektiv, kort tidsspann. Dessa stora vulkaniska utbrott har väckt stort intresse då de är samtida med flera av de största massutdöendena i jordens historia, men också för att en viss typ av sulfidmalm rik på nickel, koppar och platinametaller (Ni-Cu-PGE malmer) ofta förekommer i provinsernas magmagångar och magmakammare. En viktig faktor som till stor del avgör en magmatisk provins påverkan på klimatet och potentiella malmförekomster är inkorporering av sedimentära bergarter till magman som, när de hettas upp, kan frigöra gaser rika på svavel och kol. I Kanadas arktiska öar trängde magma tillhörande den högarktiska magmatiska provinsen (HALIP) in i svart skiffer, karbonater och evaporiter, som är sedimentära bergarter rika på flyktiga ämnen. Denna magmatiska provins erbjuder därför stora möjligheter till att studera interaktionen mellan magma och sedimentära bergarter. Syftet med denna studie är att testa om inkorporering av sedimentärt svavel kan främja bildandet av sulfidsmälta i magma och därigenom bidra till bildandet av sulfidmalmer. Detta görs genom att analysera svavelisotoper i sulfidmineral i prover från en magmagång, som trängde in i en skifferformation, tillhörande den högarktiska magmatiska provinsen i norra Kanada. Genom att analysera svavelisotopkvoten (δ34S) i sulfidmineral kan man få information om huruvida svavlet i mineralen är av sedimentärt ursprung (där skiffer generellt har negativa δ34S värden) eller om svavlet har δ34S värden liknande de från manteln (som har δ34S värden runt 0‰), vilket i så fall skulle innebära att magman inte har inkorporerat sedimentärt svavel. Genom att använda masspektrometri av typen SIMS analyseras totalt 14 sulfidmineralkorn (n = 246 individuella SIMS punkter) för deras svavelisotopkvoter. Resultatet av studien visar att alla analyserade sulfidmineral har mycket negativa δ34S värden mellan -19.5 och -5.7‰ (med ett δ34S medelvärde på -8.2 ± 0.83‰, två standardavvikelser). Genom att jämföra våra δ34S värden med δ34S och δ18O värden för andra prover från både magmagången och den omgivande skiffern kunde vi se att δ34S värdena för sulfidmineralen i de yttre delarna av magmagången har liknande negativa värden som den omgivande skiffern, och att δ34S värdena för skiffern närmast magmagången är mer positiva. Detta tyder på att sedimentärt svavel i kontakten mellan magmagången och skiffern har blivit inkorporerat i magman från den omgivande skiffern. Våra resultat tyder därför på att sulfidmineralen i våra prover från magmagången bildades genom assimilering av svavel från den omgivande skiffern. Detta innebär i sin tur att den kanadensiska högarktiska magma provinsen potentiellt kan vara en källa för sulfidmalm, även om ytterligare studier behövs. Dessutom visar våra resultat att inkorporering av sedimentärt svavel förmodligen ökade de vulkaniska gaserna i magman, vilket kan ha bidragit till klimatförändringar relaterade till den vulkaniska aktiviteten av den högarktiska magmatiska provinsen.

Com o objetivo de avaliar o potencial bioindicador de Psidium guajava e Psidium cattleyanum para avaliação da qualidade do ar em área industrial no município de Canoas, Brasil, estas espécies foram expostas em monitoramento ativo em nove pontos de amostragem, sendo cinco internos e quatro externos a área de influência de uma área industrial e mais um ponto controle localizado no Campus do Vale da Universidade Federal do Rio Grande do Sul, distando 27 Km da área de estudo. Foram realizadas cinco exposições para P. guajava e quatro para P. cattleyanum que coincidiram com as estações de inverno (2005, 2006), primavera (2005), verão (2006) e outono (2006), durante o período de um ano e três meses de monitoramento. A exposição foi feita em estandes padronizados a um metro de altura do solo, com suplementação automática de água e proteção contra o excesso de radiação. Após cada três meses de exposição foram medidos o crescimento relativo em altura, a área foliar e a biomassa total, nas duas espécies expostas.Em P. cattleyanum foi analisado também a formação de ácido malonialdeído (MDA) nas folhas primárias e em P. guajava foi analisado a fotossíntese máxima e a eficiência carboxilativa in vivo, o teor de níquel e de enxofre em folhas secas, previamente lavadas. As medidas de crescimento, área foliar e biomassa não apresentaram diferença significativa em relação ao controle para as duas espécies, o que indica que não houve danos visíveis devido à poluição atmosférica. A formação de MDA mostrou diferença significativa na coleta de verão e inverno, em sua maioria, para os pontos internos. Os teores de enxofre apresentaram valores entre 0,15 e 0,41% ficando abaixo dos níveis basais paraplantas terrestres, observando-se diferenças significativas em relação ao ponto controle, para as coletas de verão e primavera, apenas para dois pontos internos. Os teores de níquel apresentaram valores entre 0,2 e 3 μg g-1, também ficando abaixo dos níveis basais para plantas terrestres, mas apresentaram diferenças significativas em relação ao ponto controle para todas as coletas. Os pontos que apresentaram diferenças para o teor de níquel em relação ao controle foram aqueles localizados internamente na área industrial a menos de 1,5 km da potencial fonte emissora de níquel, excetuando-se a coleta de verão onde a maioria dos pontos apresentou diferenças significativas em relação ao ponto controle. A fotossíntese máxima e a eficiência carboxilativa não apresentaram diferenças significativas em nenhuma coleta. / In order to evaluate the bioindicator potential of Psidium guajava and Psidium cattleyanum to air quality monitoring, these species were exposed in an industrial area in the city of Canoas, Brazil, in ten different sites, five inner, four outside of industrial area and one control site placed at Federal University of Rio Grande do Sul. The exposures coincident with the season of winter (2005, 2006), spring (2005), summer (2006) and fall (2006) amount five exposures for P. guajava, and four exposures for P. cattleyanum. The exposition was made in a standard frame 1,0 m above the ground, with automatic supply of water and protection to excessive radiation. After three moths of exposure it was assessed total biomass, leaf area and height relative growth rate for both species. For P. cattleyanum it was assesed the content of malondialdehyde (MDA) in leaves, and for P. guajava it was assessed the nickel and sulfur content, maximum photosynthesis and carboxilation efficiency.The evaluate of total biomass, leaf area, height relative growth rate did not show any significant differences for both species, that indicate did not occur visual damage due the air pollution. MDA showed significant differences in summer and winter, mostly for inner sites. The sulfur content showed values between 0,15 and 0,41 %, below the basal level for terrestrial plants and showed significant differences in relation of control for spring and summer for three inner sites. The values of Ni showed between 0,2 and 3 μg g-1 and they were below of basal level for terrestrial plants, but showed significant differences in relation to control site for all seasons. The inner sites that showed significant differences were placed about 1,5 km from potential source emission ofNi, except in the summer whose distribution of Ni values was higher and the most of the sites showed significant differences in relation to control site. The maximum photosynthesis and the carboxilation efficiency did not show significant differences in relation to control site.

Orientador: Vitor Baranauskas / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-05T18:10:58Z (GMT). No. of bitstreams: 1 Correa_WashingtonLuizAlves_D.pdf: 3351242 bytes, checksum: 8f30a26c68d4c1e73a72d065eaedb4f9 (MD5) Previous issue date: 2004 / Resumo: Estudamos processos de dopagem do diamante crescido por deposição química a partir da fase vapor (diamante CVD) com a introdução de impurezas dopantes durante o crescimento do diamante em reatores do tipo filamento-quente. Focalizamos nossa pesquisa na dopagem do diamante com boro, ou nitrogênio, ou enxofre, visando obter diamantes com propriedades semicondutoras com condutividade eletrônica (tipo n) ou condutividade por lacunas (tipo p). Foram utilizadas contaminações intencionais utilizando: trimetil borano (B(CH3)3), ou amônia (NH3), ou dissulfeto de carbono (CS2), misturados com metano e diluídos em hidrogênio. As amostras foram caracterizadas por microscopia eletrônica de varredura (SEM), espectroscopia Raman, espectroscopia de foto-elétrons excitados por raios X (XPS), espectroscopia de emissão de raios X excitado por feixe de prótons (PIXE) e efeito Hall. As dopagens do diamante do tipo p e do tipo n foram obtidas com contaminações de boro e enxofre, respectivamente. O diamante dopado com nitrogênio não apresentou propriedades semicondutoras / Abstract: We studied the diamond doping processes with introduction of doping impurities during the diamond growth in the chemical vapor deposition (CVD) technique, using a hot-filament reactor. Our research focused the use of boron, nitrogen or sulphur atoms in order to obtain diamond films with semiconductor properties of electronic (n-type) or hole (p-type) current transport mechanisms. Trimethyl-borane (B(CH3)3), or ammonia, or carbon disulphide (CS2), mixed with methane and hydrogen were used in the feed gas mixture. The diamond samples were characterized by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Proton-induced X-ray emission (PIXE) and Hall effect. p-type and n-type diamonds have been obtained with boron and sulphur doping, respectively. However, the nitrogen doped samples do not presented semiconductor properties / Doutorado / Engenharia de Eletronica e Comunicações / Doutor em Engenharia Elétrica