Orientador: Fernando Luis Fertonani / Banca: Lídia Maria de Almeida Plicas / Banca: José Ricardo Turquetti / Resumo: O etanol é uma matriz energética que requere como especificação da qualidade a medição do parâmetro pH. A formação de recursos humanos, RH, com conhecimento metrológico em química, capaz de gerar e interpretar resultados provenientes da medição desse parâmetro e outros importantes do ponto de vista do rigor metrologia deve fazê-lo com ciência, consciência e pertinência de seu trabalho (BIÈVRE et al, 2010; GAUSTER, 1991; VALCÁRCEL, 2000). O presente trabalho utilizou de normas reguladoras para a medição do parâmetro supracitado a fim de obter a estimativa da incerteza das medidas de pHe. Também foram desenvolvidos procedimentos para a validação do método analítico de medição de pHe bem como a formação de RH devidamente treinado no sistema da qualidade para atuar no bojo das normas ABNT NBR 10891:2013 e ASTM D6423:2008. Também foi propósito deste estudo conhecer as minúcias da medição de pH em meio etanólico. O treinamento em medição de pH e rigor metrológico foi realizado em meio aquoso. No tocante a norma ABNT NBR 10891:2006 e desenvolvimento do trabalho foram coletadas três amostras de etanol combustível de postos de combustíveis distintos em que os valores obtidos estavam em conformidades com aqueles preconizados pela resolução ANP N°7:2011 isto é, 6,0 < pHe < 8,0. Para a estimativa da incerteza da medição de pHe o procedimento de validação contou com quatro parâmetros de performance, a linearidade, sensibilidade, precisão e exatidão. Os resultados obtidos da validação foram satisfatórios tornando evidente a adequação do método ao ensaio proposto. O estudo da incerteza padrão combinada demonstrou que a maior fonte de incerteza é aquela associada a repetibilidade, sendo passível de ser minimizada aplicando-se programas de treinamento técnico de pessoal, evidenciando assim a importância da adoção da metrologia no rol de disciplinas obrigatórias nos cursos da área de exatas / Abstract: Anhydrous ethanol and fuel are arrays that require energy as quality specification of the pH measurement parameter, which is set to the aqueous medium. The formation of human, HR resources, with metrological knowledge in chemistry, able to generate and interpret data from the measurement of this parameter and other important from the point of view of accuracy metrology must do so with knowledge, awareness and relevance of their work (Bievre et al, 2010; Gauster, 1991; VALCÁRCEL, 2000). This work included the study of regulatory standards for the measurement of the above parameters in order to obtain the estimated uncertainty of the measurements of pHe. Procedures for the validation of the analytical method for measuring pHe well as the formation of HR trained in the quality system to operate in the core of ABNT NBR 10891:2013 and ASTM D6423: 2008. Purpose of this study was also to know the minutiae of measuring pH in ethanol medium. The training metrological accuracy and pH monitoring was carried out in an aqueous medium. Regarding the ABNT NBR 10891:2006 and development work three samples of different ethanol fuel stations in the values obtained were in conformity with those recommended by ANP Resolution No. 7:2011 fuel between 6.0 < pHe <8.0. To estimate the uncertainty of measurement of pHe validation procedure had four performance parameters, linearity, sensitivity, precision and accuracy. The results of the validation were satisfactory pointing to the adequacy of the proposed test method. The combined standard uncertainty of the study showed that the largest source of uncertainty is that associated with repeatability, being able to be minimized by applying technical personnel training programs, thus underlining the importance of the adoption of metrology in the list of compulsory subjects in courses the exact sciences / Mestre

Made available in DSpace on 2014-11-10T11:09:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-30Bitstream added on 2014-11-10T11:57:27Z : No. of bitstreams: 1 000790646.pdf: 1026031 bytes, checksum: 4b80c5e2ed1eb5a19e291b9a89972cb7 (MD5) / O etanol é uma matriz energética que requere como especificação da qualidade a medição do parâmetro pH. A formação de recursos humanos, RH, com conhecimento metrológico em química, capaz de gerar e interpretar resultados provenientes da medição desse parâmetro e outros importantes do ponto de vista do rigor metrologia deve fazê-lo com ciência, consciência e pertinência de seu trabalho (BIÈVRE et al, 2010; GAUSTER, 1991; VALCÁRCEL, 2000). O presente trabalho utilizou de normas reguladoras para a medição do parâmetro supracitado a fim de obter a estimativa da incerteza das medidas de pHe. Também foram desenvolvidos procedimentos para a validação do método analítico de medição de pHe bem como a formação de RH devidamente treinado no sistema da qualidade para atuar no bojo das normas ABNT NBR 10891:2013 e ASTM D6423:2008. Também foi propósito deste estudo conhecer as minúcias da medição de pH em meio etanólico. O treinamento em medição de pH e rigor metrológico foi realizado em meio aquoso. No tocante a norma ABNT NBR 10891:2006 e desenvolvimento do trabalho foram coletadas três amostras de etanol combustível de postos de combustíveis distintos em que os valores obtidos estavam em conformidades com aqueles preconizados pela resolução ANP N°7:2011 isto é, 6,0 < pHe < 8,0. Para a estimativa da incerteza da medição de pHe o procedimento de validação contou com quatro parâmetros de performance, a linearidade, sensibilidade, precisão e exatidão. Os resultados obtidos da validação foram satisfatórios tornando evidente a adequação do método ao ensaio proposto. O estudo da incerteza padrão combinada demonstrou que a maior fonte de incerteza é aquela associada a repetibilidade, sendo passível de ser minimizada aplicando-se programas de treinamento técnico de pessoal, evidenciando assim a importância da adoção da metrologia no rol de disciplinas obrigatórias nos cursos da área de exatas / Anhydrous ethanol and fuel are arrays that require energy as quality specification of the pH measurement parameter, which is set to the aqueous medium. The formation of human, HR resources, with metrological knowledge in chemistry, able to generate and interpret data from the measurement of this parameter and other important from the point of view of accuracy metrology must do so with knowledge, awareness and relevance of their work (Bievre et al, 2010; Gauster, 1991; VALCÁRCEL, 2000). This work included the study of regulatory standards for the measurement of the above parameters in order to obtain the estimated uncertainty of the measurements of pHe. Procedures for the validation of the analytical method for measuring pHe well as the formation of HR trained in the quality system to operate in the core of ABNT NBR 10891:2013 and ASTM D6423: 2008. Purpose of this study was also to know the minutiae of measuring pH in ethanol medium. The training metrological accuracy and pH monitoring was carried out in an aqueous medium. Regarding the ABNT NBR 10891:2006 and development work three samples of different ethanol fuel stations in the values obtained were in conformity with those recommended by ANP Resolution No. 7:2011 fuel between 6.0 < pHe <8.0. To estimate the uncertainty of measurement of pHe validation procedure had four performance parameters, linearity, sensitivity, precision and accuracy. The results of the validation were satisfactory pointing to the adequacy of the proposed test method. The combined standard uncertainty of the study showed that the largest source of uncertainty is that associated with repeatability, being able to be minimized by applying technical personnel training programs, thus underlining the importance of the adoption of metrology in the list of compulsory subjects in courses the exact sciences

The effects of irrigation-induced salinity and/or sodicity on sugarcane yield, and two growth parameters, namely stalk height and number of nodes per stalk , were investigated on a sugarcane estate in the Zimbabwean lowveld. The effects of soil salinity and/or sodicity on the size, activity and metabolic efficiency of the soil microbial community was also studied. Furrow-irrigated fields which had a gradient in soil salinity and/or sodicity which increased from the upper to lower ends of the fields were selected for this study. This gradient was recognized by decreasing sugarcane growth down from the upper to the lower ends and the appearance of salt on the soil surface at the lower ends of fields. Sugarcane growth was classified as either dead, poor, satisfactory or good; and soil samples (0-0 .15 m, 0.15-0 .3 m, 0.3-0 .6 m and 0.6-0.9 m) were taken from each of these areas. Soils from under adjacent areas of undisturbed veld were also sampled. Sugarcane growth and yields in micro-plots of the various areas of the fields were measured. Foliar samples of sugarcane were taken at 22 weeks of age and analysed for nutrient content. Soil salinity and sodicity were quantified by measuring pH(water), electrical conductivity (ECe) and cation content of saturation paste extracts and the exchangeable cation content. From this information, the sodium adsorption ratio (SARe)and exchangeable sodium percentage (ESP) were also calculated. The calcareous, vertic soils in the study area under undisturbed veld were found to have high pH values (8 to 9.5), very high exchangeable Ca and Mg concentrations and there was evidence of accumulation of soluble salts in the surface 0.15 m. Under sugarcane production, irrigation induced salinity and sodicity had developed. Under poor and dead sugarcane, high values for ECe, SARe, and ESP were generally encountered in the surface 0-0 .3 m of the profile. In addition, the pH values under sugarcane were often between 9 and 10 particularly in profiles where sugarcane grew poorly or had died. As expected, pH was positively related to ESP and SARe, but negatively related to ECe. Measurements of aggregate stability by wet sieving, the Emerson dispersion test and the Loveday dispersion score all showed that soils from the study sited tended to disperse and that dispersion was most apparent where high ESP and SARe values occurred in association with elevated pH values and relatively low ECe values. These measurements confirmed observations at the sites of low infiltration rates and restricted drainage particularly on the lower ends of fields where sugarcane had died. In addition to the above measurements it was also observed that there was a rise in the watertable under furrow irrigation and that the watertable was nearest to the surface at the lower ends of the fields. In some cases the watertable was observed to be only 0.2 to 0.3 m from the surface. Thus, death of roots due to anaerobic conditions could be occurring to a greater extent at the lower ends of the fields. Another consequence of the high watertable was that these vertic soils were observed to remain in a permanently swollen state. This limits air and water movement in the soil profile as such soils need to be allowed to dry out and crack regularly so that macroporosity can be restored. Sugarcane yield, stalk height and number of nodes per stalk were not significantly related to ECe. Sugarcane yields were, however, significantly correlated with ESP and pH while stalk height and number of nodes were negatively correlated with ESP, SARe and pH. These results suggested that sodicity was a more limiting factor for sugarcane growth than salinity. Foliar analysis of leaf tissue did not reveal substantial differences in macro- or micro-nutrient content between good and poorly-growing sugarcane. It was concluded that the gradient of decreasing sugarcane growth down the furrow-irrigated fields, with crop death at the lower ends, was the result of a combination of factors. That is, the watertable had risen due to over-irrigation and it was nearer the surface at the lower ends of the fields. Due to capillary rise of salts, this resulted in sodic and sometimes saline-sodic conditions in the surface soil. These conditions could limit plant growth through ion toxicities, plant water stress and inhibition of root growth and function and physiological processes. These would be induced by the high pH and high salt, Na and HC03- concentrations in soil solution. Poor physical conditions associated with sodicity and the continually swollen state of the soils presumably limited infiltration and aeration in the surface soil, and probably restricted root growth. In addition, it is likely that the high watertable limited effective crop rooting depth to about 0.2 m at the lower ends of the fields. The net result was that sugarcane died at the lower ends. A negative effect of soil salinity and/or sodicity was also observed on the soil microbial population. Significant negative correlations were obtained with ECe SARe and ESP with microbial biomass C and microbial activity (as measured by FDA hydrolytic activity or arginine ammonification rate). The activity of enzymes involved in C (P-glucosidase), P (phosphatase) and S (arylsulfatase) mineralization and potential nitrogen mineralization (as determined by aerobic incubation) were also negatively correlated with these factors, with the exception of arylsulfatase activity and ESP. All the above mentioned microbial population measures were also positively correlated with soil organic C content, besides potential nitrogen mineralization. The metabolic quotient, which provides an indication of stress and efficiency of the microbial community, increased considerably with increasing salinity and sodicity and decreased with soil organic C. Thus, increasing salinity and/or sodicity resulted in a smaller, more stressed, less efficient microbial community, while the turnover rate and cycling of C, N, P and S also decreased. It was concluded that salt affected soil not only causes a decline in sugarcane yield through raising the concentration of soluble salts in soil solution, but also has a detrimental effect on microbial activity and on mineralization of soil organic C, N, Sand P. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.