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[en] Steel is a very versatile metallic material and widely used in modern life. Unfortunately, this material is prone to the phenomenon of corrosion and over time, can contribute to the failure of the product. In order to minimize this process, different types of coatings are used, due to their efficiency, economy and ease of application. The degradation of the film applied to steel by atmospheric agents is the result of the combination of various environmental factors, due to the highly destructive cyclic variations. The present work intends to determine the existence of significant statistical differences in the thickness distribution of coating in duplex systems (Fe/Zn/Paint), before and after conducting the humidity and temperature test with condensation in a constant atmosphere, from different tests carried out in the Stat graphics Centurion software. The influence of the preset conditions on the coating thickness before and after the test was demonstrated was demonstrated. These values were found in a suitable interval to guarantee the resistance to corrosion, not showing visible deterioration in the surface of the analyzed specimens.
[es]El acero es un material metálico muy versátil y ampliamente utilizado en la vida moderna. Desafortunadamente, este material está propenso al fenómeno de la corrosión y el pasar del tiempo, puede contribuir a la falla del producto. Para lograr minimizar este proceso se utilizan diferentes tipos de recubrimientos, debido a su eficacia, economía y facilidad de aplicación. La degradación de la película aplicada sobre el acero por los agentes atmosféricos es resultado de la combinación de diversos factores ambientales, debido a las variaciones cíclicas altamente destructivas. El presente trabajo pretende determinar la existencia de diferencias estadísticas significativas en las distribuciones del espesor de recubrimiento en sistemas dúplex (Fe/Zn/Pintura), antes y después de realizado el ensayo de humedad y temperatura con condensación en atmósfera constante, a partir de diferentes pruebas realizadas en el software Statgraphics Centurion. Se demostró la influencia de las condiciones prefijadas sobre el espesor de recubrimiento antes y después de realizado el ensayo. Dichos valores se encontraron en un intervalo adecuado para garantizar la resistencia a la corrosión, no evidenciándose deterioro visible en la superficie de las probetas analizadas.
[en] In this paper we present the parameters to assess during the validation activities in the Laboratory of Stable Isotope Analysis in Water, for the determination of the δ2H and δ18O isotope ratios. In the same way it includes all routine activities, calculation and statistical analysis obtained for isotopic ratios of δ2H between 25.44 and -189.48 mUr and between 2.63 and -24.78 mUr for δ18O, which are water internal standards from the laboratory.
[en] The aim of this study was to find a model able to extract the net time per unit of net worked area from different agricultural field basic shapes (square, circle, rectangle and triangle) considering the following variables: field gross area, working speed, number of turnings (these depending on the effective working width), side length parallel and orthogonal to working direction, and working direction type. Being this a non-linear problem, an approach based on artificial neural networks is proposed. The model was trained using an artificial dataset calculated for the various shapes (internal test) and then tested on 47 different agricultural operations extracted by a real field dataset for the estimation of the net time (external test). The net time records obtained from both, the trained model and the external test, were correlated and the performance parameter r was extracted. Both regression coefficients (r), for the training and internal test, appear to be excellent being equal to 0.98 with respect to traditional linear approach (0.13). The variable “number of turnings” scored the highest impact, with a value equal to 44.34% for the net time estimation. Finally, the r correlation parameter for the external test resulted to be very high (0.80). This information is very valuable of the use of information management system for precision agriculture.
[en] This work shows significant variations in the values of 210Po in different analyzed Polish voivodeships. Statistical analysis of 210Po activity concentrations in honey samples showed significant differences between place of honey collecting, kind of honey and morphological structure of plants from which bees collected nectar. (author)
[en] A new analytical method development based on solid phase extraction (SPE) combined with high performance liquid chromatography (HPLC) was carried out. The optimum working conditions were obtained based on selection of 250 mL sample loading, 0.25 μL methanol as reconstitution solvent, 100 % methanol as mobile phase and 270 nm as the optimum wavelength. Good linearity was obtained in the range of 0.015 - 400 mg/ L and the regression coefficient, R2, was 0.995. Limit of detection and quantification were calculated at LOD = 0.06 μg/ L and LOQ = 0.2 μg/ L respectively. Repeatability and robustness has showed good performance with low relative standard deviation less than 3.29 % and 3.50 % respectively. Time-of-flight mass spectrometry (TOF/ MS) instrument was used to confirm that caffeine is definitely present in surface water with level of concentration ranged from 31.7 to 50.1 μg/ L. All results were analyzed statistically using one-way ANOVA, Tukey with interval confidence 95 % and P-value 0.05. (author)
[en] Selecting the most appropriate mathematical models that can be used to evaluate an inspection system's Probability of Detection (PoD). Each model has statistical errors or accuracy for a parameter range. A PoD value is commonly evaluated with a measure of statistical confidence. There are several methods for evaluating a PoD with confidence. This article introduces a methodology of selecting PoD models using a statistical measure of model goodness of fit. Guidance is also outlined for selecting different confidence interval calculation methods. (author)