Water-in-oil (w/o) microemulsion systems, stabilised by either an anionic surfactant or a cationic surfactant were studied. The anionic system consisted of ethoxylated nonylphenol phosphate esters (Atpol), Shellsol oil and an alcohol. These microemulsions tolerated an increase in ionic strength of the water phase up to a point: Beyond this point no microemulsion could be obtained. However, adding amine salts, e.g. diethanolamine nitrite, improved the emulsification of the aqueous phase. Increasing the alcohol (cosurfactant) chain length up to octanol also increased the uptake of the aqueous phase. Thus octanol yielded the best results in terms of emulsifying large volumes of the water-phase, particularly at high salt concentrations. A key objective was to prepare stable microemulsions with high nitrite content. The maximum microemulsion nitrite contents (expressed as NaNO2equivalent by mass) achieved were: -- About 10% when a 30% NaNO2solution was emulsified -- 23% when neat diethyl ethanolamine nitrite (DEEAN) was solubilized, and -- 23% for mixtures of diethanolamine nitrite (DEtOHAN) and NaNO2 in water. The cationic microemulsion system was based on the double-chain cationic surfactant, didodecyldimethyl ammonium chloride (DDAC). In this case the solubilization of the following acetate salts were investigated: ammonium, sodium, magnesium, zinc and manganese. As with the Atpol system, it was found that increasing the ionic strength is detrimental to microemulsification of the aqueous phase. In the DDAC system, an increase in the alcohol chain length beyond butanol led to reduced aqueous phase uptake. Thus the natures and concentrations of the surfactant and the cosurfactant as well as the ionic strength of the aqueous phase determine the stability and the emulsification of large volumes of aqueous phase. In general there is an optimum ionic strength at which the salt content of the microemulsion formulation is maximised. / Dissertation (MSc (Chemistry))--University of Pretoria, 2007. / Chemistry / unrestricted

From the Introduction. The fertilisation of pineapples in the Eastern Cape Province is still a relatively new practice which started approximately twelve years ago. Even after this time many growers still insist that pineapples can be grown without fertilisation on virgin soils. As the available virgin soil decreased, however, so the interest in fertiliser application increased. Very little basic research on the fertiliser requirements of pineapples in the Eastern Cape was done to serve as a guide to growers. The available advisory literature by le Roux (1951), Malan (1954) and Lewcock (1956) were based on overseas experience. When pineapple research was started on a large scale, in 1955, it was realised that emphasis should be placed on the nutritional requirements on virgin as well as replanted soils. From initial experiments it was clear that the main response in plant growth and yield was obtained from nitrogenous fertilisers.

Modern mining explosives employ solutions of ammonium nitrate, where the solution is the oxidising component of a fuel/oxidiser mixture. This thesis is primarily concerned with the shock response of water and of aqueous solutions of ammonium nitrate. Of particular interest are the temperatures induced through shock compression. An experimental facility, using a single stage gas gun in the 'plate impact' configuration, is described, along with associated experimental diagnostics. Measurements of, and improvements to, the tilt at impact are reported. The problem of shock temperature is discussed, including a brief review of the relevant literature. It is demonstrated that direct measurement of shock temperature is a complex issue that is not yet fully understood, whereas determination of temperature from an equation of state is an established technique. In a series of experiments, plate impact techniques were utilised to determine the Hugoniot and, through shock/reload experiments, the equation of state of water and aqueous solutions of ammonium nitrate. In-situ manganin gauges were used to measure stresses in the liquids and, from the arrival times of the shock wave, determine the shock velocity. Linear shock velocity-particle velocity Hugoniots for the liquids were determined, up to particle velocities of 1km/s, with uncertainties on the intercept and slope of these Hugoniots of 5%. A Mie-Grûneisen equation of state was used to describe the shock/reload experiments. Approximate calculations of shock temperature are reported. Increasing ammonium nitrate concentrations resulted in greater calculated temperatures. It was demonstrated that the liquids investigated in this thesis show a temperature dependence of the Grûneisen parameter, ?, which cannot be accommodated in the model. The present work is believed to be the first demonstration of this effect in shock compressed liquids. The data presented provide constraints on future theoretical development of equations of state.

No description available.

Quaternary ammonium salts are surface active bactericides. A mechanism of their biological activity has been well studied experimentally, and it encompasses two stages. The first stage involves electrostatic interactions of polar functional groups of the salts with oppositely charged functional groups on a bacterial cell surface, and the second stage includes incorporation of their lipophilic groups into a bacterial cell membrane. However, despite numerous experimental studies, computational modelling of this mechanism with the aim to support experimental observations with theoretical conclusions, to the author's knowledge, has not yet been reported. In the current study, linear regression models correlating theoretical descriptors of lipophilicity and electronic properties of mono- and disubstituted imidazolium carboxylates with their biological activity towards Escherichia coli have been developed. These models established that biological activity of these salts is governed by the chemical structures of imidazolium cations, and that the centre of this biological activity is located in the long alkyl side chains of the cations. It was also found that these side chains have an intrinsic electronic potential to form internal C-H- -H-C electrostatic interactions when their lengths reach seven carbon atoms. Additionally, the nature of the C-H- -O-C inter-ionic electrostatic interactions in imidazolium carboxylates has been explored via a topological analysis of these interactions in 1-ethyl-3-methylimidazolium acetate. Thus, it was established that these electrostatic interactions are hydrogen bonds.

Atmospheric aerosols are the major component in the shorter-term variability governing the radiative balance of the climate system, particularly on regional scales. However, knowledge of the myriad of properties and processes associated with aerosols is often limited, which results in major uncertainties when assessing their climate effects. One such aspect is the chemical make-up of the atmospheric aerosol burden.Airborne measurements of aerosol properties across Northern Europe are presented here in order to facilitate constraint of the properties, processes and effects of aerosols in this highly populated and industrialised region. An Aerodyne Aerosol Mass Spectrometer (AMS) delivered highly time-resolved measurements of aerosol chemical components, which included organic matter, sulphate, nitrate and ammonium.The chemical composition of the aerosol burden was strongly determined by the dominant meteorological conditions in Northern Europe. Pollution loadings in North- Western Europe were strongly enhanced when air masses originated from Continental Europe. Conversely, much cleaner conditions were associated with air masses from the Atlantic Ocean.Organic matter was found to be ubiquitous across Northern Europe and predominantly secondary in nature, which is consistent with other analyses in polluted regions of the Northern Hemisphere. Furthermore, its concentration was generally comparable to, or exceeded that of, sulphate. Significant chemical processing of the organic aerosol component was observed. Highly oxidised secondary organic aerosol dominated, as the distance from source and photochemical processing increased.Ammonium nitrate was found to be a major component of the aerosol burden in Northern Europe, with peak contributions occurring in North-Western Europe, due to the co-location of its emission precursors (NH3 and NOx) in the region. Ammonium nitrate was found to be the dominant sub-micron chemical constituent during periods associated with enhanced pollution episodes. Its concentration was shown to be modulated by the thermodynamic structure of the lower troposphere, with enhanced concentrations prevalent at the top of the boundary layer. This phenomenon greatly enhanced the radiative impact of the aerosol burden; the increased mass and water uptake by the aerosol significantly amplified the aerosol optical depth in the region.The results presented in this thesis highlight a highly dynamic region, where major changes in emissions have played a significant role in determining the chemical composition of the aerosol burden. As substantial reductions in sulphur dioxide emissions have occurred over the past two decades in Northern Europe, the relative contribution of sulphate aerosols to the regional aerosol burden has decreased. Consequently, it is more pertinent to consider the roles of organic matter and ammonium nitrate, as their influence becomes more pronounced than sulphate on regional and global climate.

Submitted by Michele Mologni (mologni@unoeste.br) on 2017-08-29T18:26:47Z No. of bitstreams: 1 Eliane Batista Viudes.pdf: 1015185 bytes, checksum: 988509ea575caceeed70fa62e6a8e173 (MD5) / Made available in DSpace on 2017-08-29T18:26:47Z (GMT). No. of bitstreams: 1 Eliane Batista Viudes.pdf: 1015185 bytes, checksum: 988509ea575caceeed70fa62e6a8e173 (MD5) Previous issue date: 2016-11-24 / In this work, tobacco plants with a high proline accumulation due to the insertion of the VaP5CSF129A mutant gene on the control of the promoter constitutive CaMV 35S were used as a model to verify the effect of transgene overexpression on the uptake and utilization of N. The experiment was conducted in a greenhouse for a period of 30 days. The arrangement was completely randomized in the 2x5 factorial scheme, consisting of two genotypes (one transgenic event and one unprocessed control) and five nitrogen fertilization doses (ammonium nitrate (NO3NH4): 25, 50, 100, 200 and 400 kgN ha-¹), totaling 10 treatments with 4 replicates. The plants were evaluated for height, leaf number, dry mass, root/shoot ratio, chlorophyll content, free proline content, nitrogen content, total protein foliar content, carbon/nitrogen ratio and nutritional efficiency for N (Absorption efficiency - EAbs, leaf utilization - EUtil and plant use - EUN). The plants of the transgenic event with high proline accumulation were less efficient than the control plants in terms of nitrogen absorption (lower levels of N in root, leaves and role plant), which resulted in lower EAbs in these plants. For EUtil (given by the relation between leaf dry mass and N content in the plant) there was no difference between the transgenic and control genotypes. However, the transgenic plants presented lower EUN in comparison to the control plants. It was concluded that the use of tobacco plants with overexpression of the VaP5CS129A gene on control of the constitutive promoter CaMV 35S for a high proline accumulation does not present potential of direct use in agricultural systems, since the alteration of the biochemical balance between the metabolisms of nitrogen and carbon did not result in plants with higher EUN. / O aumento da eficiência de uso do nitrogênio (EUN) nas plantas cultivadas é resultado da melhoria da absorção e/ou da utilização do N. Nesse trabalho, plantas de tabaco com alto acúmulo de prolina devido à inserção do gene mutante VaP5CSF129A sobre controle do promotor constitutivo CaMV 35S foram utilizadas como modelo para verificar o efeito da super-expressão do transgene na absorção e utilização de N. O experimento foi conduzido em casa de vegetação por um período de 30 dias. O arranjo foi inteiramente casualizado, no esquema fatorial 2x5, formado por dois genótipos (um evento transgênico e um controle não transformado) e cinco doses de adubação nitrogenada (nitrato de amônio (NO3NH4): 25, 50, 100, 200 e 400 kgN ha-¹), totalizando 10 tratamentos com 4 repetições. As plantas foram avaliadas quanto à altura, número de folhas, massa seca, razão raiz/parte aérea, teor de clorofila, teor de prolina livre, teor de nitrogênio, teor foliar de proteína total e eficiência nutricional quanto ao N (eficiências de absorção - EAbs, utilização na folha - EUtil e uso na planta - EUN). As plantas controle e transgênicas responderam de forma positiva ao incremento de N no solo, tanto em relação às variáveis de crescimento quanto aos parâmetros bioquímicos. As plantas transgênicas apresentaram menor biomassa e maiores teores de compostos nitrogenados nas folhas (na forma de prolina e proteínas) quando comparadas às plantas controle. Quanto à eficiência nutricional, as plantas transgênicas foram menos eficientes que as plantas controle quanto à absorção de nitrogênio (menores teores de N na raiz, nas folhas e na planta); o que resultou portanto em uma menor EAbs nestas plantas. Para a EUtil (dada pela relação entre a massa seca de folhas e o teor de N na planta) não houve diferença entre os genótipos transgênico e controle. Porém, as plantas transgênicas apresentaram menor EUN em comparação às plantas controle. Concluiu-se que o uso de plantas de tabaco com super-expressão do gene VaP5CS129A sobre controle do promotor constitutivo CaMV 35S para um alto acúmulo de prolina não apresenta potencial de utilização direta em sistemas agrícolas, desde que a alteração do equilíbrio bioquímico entre os metabolismos de nitrogênio e do carbono não resultou em plantas com maior EUN.

A fermentação de mosto com alta concentração de açúcar (ACA) pode ser utilizada em escala industrial para a produção de etanol combustível. Esta tecnologia apresenta vantagens como a obtenção de níveis mais elevados de etanol e a minimização dos custos de produção, em contraposição apontam novos desafios, como minimizar os efeitos do estresse, osmótico e alcoólico, que as leveduras são submetidas. A suplementação do mosto com fontes nitrogenadas pode aumentar o rendimento de etanol durante a fermentação alcoólica, visto que este elemento desempenha importantes funções na fisiologia da levedura. Para avaliar o efeito da suplementação de mosto ACA, caldo de cana-de-açúcar concentrado a 25°, 30° e 35°Brix e suplementado com sulfato de amônio foi fermentado por linhagens comerciais de levedura, PE-2 e CAT-1, a 30ºC e 60rpm e monitorado por ciclos de 24 horas. Seis ciclos fermentativos foram realizados, mediante o reciclo das células de levedura por centrifugação a 2.000 g por 15 min. Os parâmetros analisados foram o desprendimento de CO2 obtido por avaliação da massa (pesagem em balança analítica); viabilidade celular determinada pelo método de coloração com eritrosina; teor alcoólico determinado em densímetro digital, após destilação da amostra, análise de açúcares totais e residuais por cromatografia de troca iônica e a concentração de nitrogênio assimilável determinada colorimetricamente pelo método da ninidrina, utilizando glicina como padrão. A suplementação dos meios com sulfato de amônio propiciou maiores taxas reprodutivas das leveduras, formando maior biomassa em todas as concentrações de Brix estudadas. Os valores de etanol observados foram superiores nas amostras suplementadas, atingindo um teor acima de 16% (v/v) para a linhagem CAT-1 e acima de 15,5% (v/v) para a linhagem PE-2 no mosto contendo 30°Brix. Entre as linhagens, a CAT-1 foi a que suportou melhor a pressão osmótica do meio e, consequentemente, apresentou produtividade fermentativa superior, atingindo uma produção acima de 5,2g/L/h. A presença da fonte de nitrogênio mostrou ser fundamental para o processo fermentativo, principalmente em mosto ACA, com concentrações mais elevadas de açúcar. A fermentação do mosto com 25°Brix não apresentou o mesmo comportamento. / The fermentation of sugar cane wort with a high concentration of sugar (ACA, very high gravity) can be used on an industrial scale for the production of fuel ethanol. This technology has the advantage of achieving higher levels of ethanol and reduction of production costs, although the challenges are to minimize the effects of osmotic and alcohol stress that the yeasts are subjected. Supplementation with nitrogen sources provides important roles in the physiology of yeast and it can increase the yield of ethanol during fermentation. To evaluate the effect of supplementation of ACA wort, juice of sugar cane was concentrated at 25°, 30° and 35°Brix and supplemented with ammonium sulfate. The medium was fermented by commercial yeast strains, PE-2 and CAT-1, at 30° C, with orbital shaking. The process was followed in 24 hours cycles. Six fermentation cycles were performed with the yeast cells recycling. At the end of each cycle, the yeast biomass was separated from liquid fraction by centrifugation at 2,000 g for 15 min. Progress of fermentations was analyzed by measuring CO2 production by evaluating the mass reduction; yeast cell viability by staining method with erythrosine; alcoholic content of distilled sample was determined by densitometry, residual sugars were analyzed by ion exchange chromatography and assimilable nitrogen concentration determined colorimetrically by ninhydrin method, using glycine as standard. The strains PE-2 and CAT-1 with ammonium sulfate reached higher reproductive rates and improved biomass at all sugar concentrations. Higher ethanol production was observed in the supplemented samples, reaching a level above 16% (v/v) for CAT-1 strain and above 15.5% (v/v) for PE-2 strain at 30° Brix concentration. CAT-1 strain showed more tolerance with the high osmotic pressure of the medium and consequently improved productivity fermentation, reaching an ethanol production above 5.2 g/L.h. Nitrogen source proved to play a crucial role in the fermentation process, mainly in ACA wort, however, the same effect was not observed at 25°Brix.

Orientador: Enes Furlani Junior / Resumo: O N é um dos elementos mais dinâmicos no solo, conforme sua transformação no meio. A lixiviação de nitrato e do amônio no solo é considerada a principal perda do N disponível às plantas, quanto maior for à aplicação deste elemento no solo, maior será o potencial de poluição do solo e da água. Objetivou-se, neste trabalho, avaliar a lixiviação de amônio e nitrato em um Latossolo Vermelho em diferentes profundidas do solo, em função de doses e fontes de N distintas, em sistemas irrigado e não irrigado nas condições de campo. O experimento foi conduzido no ano agrícola 2014/15, na área experimental da fazenda de ensino, pesquisa e extensão, localizada no município de Selvíria-MS. Utilizou-se o delineamento em blocos casualizados, com 20 tratamentos dispostos em fatorial 5x2x2, com 4 repetições. Aplicou-se 5 doses de nitrogênio (0 (testemunha); 25; 50; 100 e 150 kg de N ha-1), as fontes de N utilizadas foram: nitrato de amônio e a ureia, aplicados em uma única adubação de cobertura via solo aos 45 após a emergência. As amostras de solo colhidas foram analisadas em laboratório, para a determinação da concentração da lixiviação do NO3- e do NH4+ no solo. Avaliou – se os parâmetros de crescimento, estado nutricional e da produtividade do algodoeiro durante seu ciclo. Os resultados permitiram concluir que o sistema irrigado foi o que propiciou maior lixiviação dos teores de nitrato e amônio nas profundidades de 0 a 0,8 m do solo e o sistema não irrigado foi o que apresentou maior con... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The N is one of the most dynamic elements in the soil, according to its transformation in the environment. The leaching of nitrate and ammonium in the soil is considered the main loss of the N available to the plants, the greater the application of this element in the soil, the greater the pollution potential of soil and water. The objective of this work was to evaluate the leaching of ammonium and nitrate in a Red Latosol in different depths of the soil, as a function of different N sources and sources, in irrigated and non-irrigated systems under field conditions. The experiment was conducted in the agricultural year 2014/15, in the experimental area of the teaching, research and extension farm, located in the municipality of Selvíria, Brasil state of mato grosso do sul. A randomized complete block design was used, with 20 treatments arranged in 5x2x2 factorial, with 4 replications. Five nitrogen doses (0 (control), 25, 50, 100 and 150 kg of N ha-1) were applied, the N sources used were: ammonium nitrate and urea, applied in a single cover fertilization only at 45 after the emergency. The soil samples collected were analyzed in the laboratory for the determination of the leaching concentration of NO3- and NH4+ in the soil. The parameters of growth, nutritional status and yield of cotton during its cycle were evaluated. The results allowed to conclude that the irrigated system provided the highest leaching of the nitrate and ammonium contents in the 0 to 0,8 m depths of the ... (Complete abstract click electronic access below) / Mestre

The objective of this research is to evaluate a coastal prediction system under various real world scenarios to test the efficacy of the system as a management tool in Tampa Bay. The prediction system, comprised of a three-dimensional numerical circulation model and a Lagrangian based particle tracking model, simulates oceanographic scenarios in the bay for past (hindcast), present (nowcast) and future (forecast) time frames. Instantaneous velocity output from the numerical circulation model drives the movement of particles, each representing a fraction of the total material, within the model grid cells. This work introduces a probability calculation that allows for rapid analysis of bay-wide particle transport. At every internal time step a ratio between the number of particles in each individual model grid cell to the total number of particles in the entire model domain is calculated. These ratios, herein called transport quotients, are used to construct probability maps showing locations in Tampa Bay most likely to be impacted by the contaminant. The coastal prediction system is first evaluated using dimensionless particles during an anhydrous ammonia spill. In subsequent studies biological and chemical characteristics are incorporated into the transport quotient calculations when constructing probability maps. A salinity tolerance is placed on particles representing Karenia brevis during hindcast simulations of a harmful algal bloom in the bay. Photobleaching rates are incorporated into probability maps constructed from hindcast simulations of seasonal colored dissolved organic matter (CDOM) transport. The coastal prediction system is made more robust with the inclusion of biological parameters overlaid on top of the circulation dynamics. The system successfully describes the basic physical mechanisms underlying the transport of contaminants in the bay under various real world scenarios. The calculation of transport quotients during the simulations in order to develop probability maps is a novel concept when simulating particle transport but one which can be used in real-time to support the management decisions of environmental agencies in the bay area.