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Abstract:The best Weibull distribution methods for the assessment of wind energy potential at different altitudes in desired locations are statistically diagnosed in this study. Seven different methods, namely graphical method (GM), method of moments (MOM), standard deviation method (STDM), maximum likelihood method (MLM), power density method (PDM), modified maximum likelihood method (MMLM) and equivalent energy method (EEM) were used to estimate the Weibull parameters and six statistical tools, namely relative percentage of error, root mean square error (RMSE), mean percentage of error, mean absolute percentage of error, chi-square error and analysis of variance were used to precisely rank the methods. The statistical fittings of the measured and calculated wind speed data are assessed for justifying the performance of the methods. The capacity factor and total energy generated by a small model wind turbine is calculated by numerical integration using Trapezoidal sums and Simpson's rules. The results show that MOM and MLM are the most efficient methods for determining the value of k and c to fit Weibull distribution curves.

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The extensive use of fossil fuels is depleting its reserve and produces harmful emission causing environmental issues. Hence, considerable attention has been given to alternative sources such as biodiesel. Currently, biodiesel is mainly produced from conventionally grown edible oil plants thus leading to a competition of usage of food versus fuel. The increasing criticism of the sustainability of first generation biodiesels (those derived from edible oils) has raised attention to the use of so-called second and third generation biodiesels. The second generation biodiesel includes nonedible vegetable oils, waste cooking oils as well as animal fats. These are considered as promising substitute for traditional edible food crops as they neither compete with food crops nor lead to land-clearing. This study introduces second generation biodiesel to be used as biodiesel feedstocks. Several aspects of these feedstocks are reviewed and discussed in this paper. These aspects include different sources of biodiesel feedstocks, biodiesel conversion technology and performance and emission characteristics of second generation biodiesel.

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