Indian Institute of Technology Kharagpur

About: Indian Institute of Technology Kharagpur is a education organization based out in Kharagpur, India. It is known for research contribution in the topics: Computer science & Dielectric. The organization has 16887 authors who have published 38658 publications receiving 714526 citations.

Normalized Power Curves as a Tool for Identification of Optimum Wind Turbine Generator Parameters

Abstract: This paper presents a novel method of matching wind turbine generators to a site using normalized power and capacity factor curves. The site matching is based on identifying optimum turbine speed parameters from the turbine performance index curve, which is obtained from the normalized curves, so as to yield higher energy production at a higher capacity factor. The wind speeds are parameterized using a cubic mean cuberoot and statistically modeled using the Weibull probability density function. An expression for a normalized power and capacity factor, expressed entirely in normalized rated speed, is derived. The wind turbine performance index, a new ranking parameter, is defined to optimally match turbines to a potential wind site. The plots of normalized power, capacity factor, and turbine performance index versus normalized rated wind speed are drawn for a known value of the Weibull shape parameter of a site. Usefulness of these normalized curves for identifying optimum wind turbine generator parameters for a site is presented by means of two illustrative case studies. The generalized curves, if used at the planning and development stages of wind power stations, will serve as a useful tool to make a judicious choice of a wind turbine generator that yields higher energy at a higher capacity factor.

Indian Ocean high-productivity event (10–8 Ma): Linked to global cooling or to the initiation of the Indian monsoons?

Abstract: Uplift of the Himalayas and Tibetan Plateau (ca. 10-8 Ma) has been said to be the main cause of the origin or intensification of the Indian monsoon system, because mountains modulate the land-sea thermal contrast. The intensification of the monsoons, in turn, is seen as the cause of major changes in fauna and flora on land (as a result of changing precipitation patterns) as well as in the Indian Ocean, where the monsoons drive increased upwelling and thus increased productivity. We argue that the interactions between the elevation of the Himalayas and Tibetan Plateau, the onset of the monsoons, and their effects on the Indian Ocean biota remain uncertain. The timing of these events (uplift, monsoons, and biotic change) is not well constrained. Neogene deep-sea benthic foraminiferal faunal and isotope records of the Ninetyeast Ridge combined with published data show that a major increase in bio- genic productivity occurred at 10-8 Ma throughout the Indian Ocean, the equatorial Pacific, and southern Atlantic. We suggest that this Indian Ocean high-productivity event was not simply the result of monsoon-induced upwelling or nutrient delivery from the weathering of newly uplifted mountains, but may have been caused by strengthened wind regimes resulting from global cooling and the increase in volume of the Antarctic ice sheets.

Risk analysis using FMEA

Abstract: The study enhances the capability of FMEA as a risk assessment tool.It uses fuzzy similarity value based measurement.It demonstrates the applicability of possibility theory in decision making.It considers two case studies.The results are compared with traditional methods. Fuzzy numerical technique for FMEA has been proposed to deal with the drawbacks of crisp FMEA and fuzzy rule based FMEA approaches. Fuzzy numerical approaches based on de-fuzzification also suffer from the drawback of providing arbitrary priority ranks of failure modes even when their membership functions overlap. To overcome this drawback we developed a new methodology integrating the concepts of similarity value measure of fuzzy numbers and possibility theory. Similarity value measure has been applied to group together failure modes having similar amount of risk value. The possibility theory has been used for checking for conformance guidelines. Two case studies have been shown to demonstrate the methodology thus developed. The proposed methodology is more robust in nature as it does not require arbitrary precise operations like de-fuzzification to prioritise the failure modes. Application of possibility theory is new to the domain of risk analysing using FMEA.