Faculty Publications

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Subject: search.filters.subject.Evaluation

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    Performance analysis of compensation current extraction techniques for 3Φ, 3-wire shunt active power filter under unbalanced supply
    (2009) Gonda, J.M.; Anantha Adithya, V.; Sumam David, S.
    Actve power filters are effective in mitgating line current harmonics and compensating for the reactive power in the line. Many papers comparing the performance of active power filter extraction algorithms are found in the literature, but there is explicit mention about the suitability of any particular extraction algorithm under all conditions. Hence this paper is an attempt to compare the performance of direct methods of compensating current extraction algorithms for three-phase active power filters under different conditions of mains supply using Matlab/Simulink™. Both transient and steady state conditions are considered. The compensating techniques under analysis are: synchronous detection method, sychronous reference frame method, id-iq method, instantaneous active reactive power theory (p-q theory) modied p-q theory, adaptive noise cancellation, notch filtering and Fourier based sinusoidal subtraction algorithms. Under balanced conditions all the compensatng techniques give proper result, but under balanced conditions only few of the compensating techniques work satisfactorily. In fact the equal resistance synchronous detection method and Fourier based sinusoidal subtraction algorithms perform better under extreme conditions. With proper implementation, sinusoidal subtraction algorithm performs better under both transient and steady state conditions. © 2009 IEEE.
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    Evaluation of chirps satellite rainfall datasets over kerala, india
    (Springer Science and Business Media Deutschland GmbH, 2021) Divya, P.; Shetty, A.
    Climate hazard group infrared precipitation with station data (CHIRPS) is one of the latest high-resolution quasi-global satellite-based rainfall datasets. It is available in daily, pentadal and monthly time scale from the year 1981 to present. In the present study, the performance of the CHIRPS product is evaluated over the Kerala state on a monthly time scale. For the evaluation of this climate hazard group, product rain gauge data from sixty-seven-gauge stations which are distributed all over Kerala was used. Validation statistics such as mean absolute error (MAE), multiplicative bias (Mbias), Nash–Sutcliffe efficiency (NSE) and coefficient of determination (R2) were used for the evaluation. The results show that the efficiency of this satellite rainfall estimate is very high with an overall NSE value of 0.72. The accuracy of CHIRPS data was very high mainly in the low-lying areas of Kerala, i.e. at the coastal areas and it was found to be decreasing when in approaches towards the Western Ghats. Overall CHIRPS product is good enough for use in water resource applications in Kerala. © Springer Nature Singapore Pte Ltd 2021.
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    Synthesis and evaluation of fexofenadine analogue for antihistaminic, anticholinergic and sedative activities
    (Chemical Publishing Co., 2007) Sathish, N.K.; Bhagavanraju, M.; Hemamalini, K.; Gopkumar, P.; Narendra, V.; Rajendra Prasad, V.V.S.
    A novel ?-[4-isopropyl phenyl]-4-(hydroxy diphenyl methyl)-1-piperidinyl)butan-1-one (II) has been synthesized by Friedel Craft's acylation and condensation reaction. The structures of the synthesized compounds were elucidated by (IR, PMR and Mass) spectral analysis. The compound synthesized was screened for anti-histaminic activity by histamine induced contractions using guinea pig ileum, anticholinergic by guinea pig tracheal chain and sedative activity. The compound exhibited significant anti-histaminic activity.
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    Evaluation of right-turn lanes at signalized intersection in non-lane-based heterogeneous traffic using microscopic simulation model
    (Maney Publishing michael.wagreich@univie.ac.at, 2015) Asaithambi, G.; Sivanandan, R.
    In developing countries like India, the traffic on urban roads is highly heterogeneous in nature, with vehicles of widely varying static and dynamic characteristics. This type of traffic is characterized by lack of queue and lane discipline (lane-less movement) based on availability of spaces near intersections. Moreover, at intersections, straight-through, left-, and right-turning vehicles seek to occupy the same physical space. In such situations, the through vehicles are susceptible to delays in the absence of turn lanes for the left-turning and right-turning vehicles and vice versa. Models suitable for analysis of such traffic flow hardly exist, and most of the available models are limited in scope. In the current study, a microscopic traffic simulation model for signalized intersection is developed specifically for heterogeneous traffic. This model covers different vehicle types and allows for some special behavior, such as seepage of two-wheelers to fronts of queues. Detailed study of queue formation and dissipation were done microscopically under non-lane-based traffic conditions near intersection area. The model was calibrated and tested with data from Chennai city, India, and its predictions were found to be in close agreement with the field data. In addition, the model makes a significant contribution to the study of right-turn lane (RTL) on delays to vehicles. In general, RTL is found to be advantageous for most cases of approach volumes and right-turn proportions. The optimal lengths of RTL are suggested for various approach volumes and right-turn proportions. © 2015 W. S. Maney & Son Ltd.
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    Electro-discharge machining of microholes on 3d printed Hastelloy using the novel tool-feeding approach
    (KeAi Publishing Communications Ltd., 2025) Korgal, A.; Shettigar, A.K.; P, N.K.; Kumar, N.; Bindu Madhavi, B.M.
    Hastelloy, a nickel-based superalloy renowned for its exceptional resistance to corrosion at high temperatures, is widely used in sectors such as nuclear, aerospace, chemical processing, and pharmaceuticals. Microelectrical discharge machining (?-EDM) is crucial for generating microholes and channels on Hastelloy. Since it effectively addresses difficulties like work hardening, high strength & wear resistance, and low thermal conductivity in traditional machining. Microholes play a major role in many critical components for precise control of fluids in fuel injectors, managing heat in turbine blades, controlled gas exchange, etc. The current research investigates the drilling of 8:1 aspect ratio microholes machined by 400 ?m diameter electrodes. This study investigated the influence of tool material (tungsten carbide, carbide drill bit, and brass) on ?-EDM performance. Compared to tungsten carbide and carbide drill bits, brass exhibited significantly lower electrode wear, leading to more precise microholes with reduced overcut and taper angle. However, brass also required a substantially longer machining time. Carbide drill bits offered a balance between wear resistance, machining time, and overcut/taper angle. © 2024 The Authors