24 research outputs found

    Knowledge management: Dispelling myths and finding directions

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    Knowledge Management, a widely misused term, with a string of misconceptions attached to it, is our main target of this working paper.Here, we hope to identify some, if not most, myths associated with Knowledge Management, as well as delve into the reasons behind these myths and then find some possible directions/solutions, based on success stories among business organizations from various disciplines, to dispel them so that Knowledge Management can be utilized to its full potential.Our paper incorporates the myths in Knowledge Management and directions to dispel the myths so that Knowledge Management can be improved

    Non-Gaussian Wind Pressure Characteristics of HAWT Tower System with and Without Rotor

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    Generally, the Gaussian assumption has been considered in analyzing the data pertaining to the wind effects on the structures or bluff bodies due to the abundance of the statistical information. In this study, Horizontal Axis Wind Turbine (HAWT) tower system with dimension of 1:330 scale is studied in order to understand their peak pressure behavior for wind resistant design. Generally, tower systems are constructed of various geometrical structures such as lattice towers, tubular steel towers, concrete towers, but in this present study tubular cylindrical tower is only considered. Simultaneous pressure measurements on the surface of the tower were performed in the low-speed boundary layer wind tunnel with test section dimension of 18 m × 2.5 m × 2.15 m having Reynolds number ranging from 102 to 104. The peak pressures acting on the tower systems are calculated for a number of ten-minute samples on various locations of the wind turbine. Peak value calculations based on Gaussian and Non – Gaussian processes are discussed mathematically and applied to the data collected from the wind tunnel tests. A mathematical model of Davenport and Kareem – Zhou is used in calculating the peak factor for Gaussian and non – Gaussian processes, respectively. The results indicate that higher moments dominate as most of the distribution is skewed and with kurtosis value. Henceforth, a study on extreme value analysis is deemed necessary in designing wind resistant structures or bluff bodies. Considering Gaussian nature alone may under-represent the peak value of the HAWT tower

    Large-scale unit commitment under uncertainty: an updated literature survey

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    The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject

    Pressure distribution of rotating small wind turbine blades with winglet using wind tunnel

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    425-429This study presents pressure distribution over an envelope of blade with and without winglets for a small wind turbine in boundary layer wind tunnel. Different winglet configurations were tried based on winglet height and curvature radius. Pressure measurements were made with different chordwise and spanwise locations on the blade with and without winglets nearby tip region. Winglet improves overall pressure difference between pressure surface and suction surface. Presence of winglet seemed to have the pressure increased at 0.3c and maximum pressure difference was observed at a span of 0.95R for all winglet configurations. In suction, surface pressure decrease was 10% for all winglet configurations

    Electrochemical studies on electroless ternary and quaternary Nix20P based alloys

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    The autocatalytic (electroless) deposition of Nix2013;P based alloys is a well-known commercial process that has found numerous applications because of their excellent anticorrosive, wear, magnetic, solderable properties, etc. It is a barrier coating, protecting the substrate by sealing it off from the corrosive environments, rather than by sacrificial action. The corrosion resistance varies with the phosphorus content of the deposit: relatively high for a high-phosphorus electroless nickel deposit but low for a low-phosphorus electroless nickel deposit. In the present investigation ternary Nix2013;Wx2013;P alloy films were prepared using alkaline citrate-based bath. Quaternary Nix2013;Wx2013;Cux2013;P films were deposited by the addition of 3mM copper ions in ternary Nix2013;Wx2013;P bath. X-ray diffraction (XRD) studies indicated that all the deposits were nanocrystalline, i.e. 1.2, 2.1 and13; 6.0 nm, respectively, for binary, ternary and quaternary alloys. Corrosion resistance of the films was evaluated in 3.5% sodium chloride solution in non-deaerated and deaerated conditions by potentiodynamic polarization and electrochemical impedance (EIS) methods. Lower corrosion current density values were obtained for the coatings tested in deaerated condition. EIS studies showed that higher charge transfer resistance values were obtained for binary Nix2013;P coatings compared to ternary or quaternary coatings. For all the coatings a gradual increase in the anodic current density had been observed beyond 740mV. In deaerated condition all the reported coatings exhibited a narrow passive region and all the values of Ep, Etp and ipass were very close showing no major changes in the electrochemical behavior. In the non-deaerated conditions no passivation behavior had been observed for all these coatings.13; xA9; 2006 Elsevier Ltd. All rights reserved

    A controlled experiment to verify the effect of magnesium fertilizers on soil pH and available soil nutrients in acid soil of Nilgiris, India

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    An incubation experiment was conducted in laboratory conditions for 60 days to observe the impact of different Magnesium fertilizers on soil chemical properties, i.e. pH, available nitrogen, phosphorus, potassium, and DTPA extractable micronutrient cations. A complete factorial complete randomized block design (FCRD)with two replications and six levels was selected as the experimental layout. The levels included were (L0) Absolute control (L1) soil + Mg @ 10 kg ha-1, (L2) soil + Mg @ 20 kg ha-1, (L3) soil + 30 kg ha-1, (L4) soil + 40 kg ha-1, (L5) soil + 50 kg ha-1. Findings revealed that applying magnesium fertilizers to soil significantly (p ≤ 0.05) affects soil parameters. The impacts of magnesium fertilization on soil pH altered with sources and incubation period. The application of CaMg(CO3)2 @ 50 kg ha-1 recorded significantly (p ≤ 0.05) higher soil pH (5.67) as compared to MgCO3 @ 50 kg ha-1 that increased the pH up to 5.57 due to the impact of carbonate ion whereas MgSO4.7H2O decreased the soil up to 4.80 because of dissolution of SO42- ions to the soil solution.  Applying CaMg(CO3)2 significantly (p ≤ 0.05) influenced soil available N, P, K, Fe, Mn, and Cu content which is due to the decrease in acidity, which indirectly enhanced the nutrient availability.  The positive effects persisted throughout the experimental duration, indicating the potential long-term benefits of magnesium fertilization in acid soil management. This study contributes to the current body of knowledge by providing novel insights into applying magnesium fertilizers as an effective strategy for addressing soil acidity and improving nutrient availability in acid soil
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