In this paper we have proposed some new techniques based on the centroid of triangular and trapezoidal fuzzy numbers to solve a fuzzy linear programming problem. These proposed methods are easy to ...implement with less number of arithmetic operations required compared to the existing methods. To illustrate the proposed method, numerical examples are given. A comparative study between the proposed methods and existing methods are given at the end.
The superiority of these centroid based methods over known ranking function method has also been shown with an example. KCI Citation Count: 0
The low to medium-rank Tertiary coals from Meghalaya, India, are explored for the first time for their comprehensive microstructural characterization using the FTIR and Raman spectroscopy. Further, ...results from these coals are compared with the Permian medium and high-rank coals to understand the microstructural restyling during coalification and its controls on hydrocarbon generation. The coal samples are grouped based on the mean random vitrinite reflectance values to record the transformations in spectral attributes with increasing coal rank. The aliphatic carbon and the apparent aromaticity respond sharply to the first coalification jump (
R
¯
r
: 0.50%) during low to medium-rank transition and anchizonal metamorphism of the high-rank coals. Moreover, the Raman band intensity ratio changes during the first coalification jump but remains invariable in the medium-rank coals and turns subtle again during the onset of pregraphitization in high-rank coals, revealing a polynomial trend with the coal metamorphism. The Rock–Eval hydrogen index and genetic potential also decline sharply at the first coalification jump. Besides, an attempt to comprehend the coal microstructural controls on the hydrocarbon potential reveals that the Tertiary coals comprise highly reactive aliphatic functionalities in the type II-S kerogen, along with the low paleotemperature (74.59–112.28 °C) may signify their potential to generate early-mature hydrocarbons. However, the presence of type II-III admixed kerogen, a lesser abundance of reactive moieties, and overall moderate paleotemperature (91.93–142.52 °C) of the Permian medium-rank coals may imply their mixed hydrocarbon potential. Meanwhile, anchizonal metamorphism, polycondensed aromatic microstructure, and high values of paleotemperature (~ 334.25 to ~ 366.79 °C) of the high-rank coals indicate a negligible potential of producing any hydrocarbons.
The increasing use of gibberellic acid (GA
3
) to promote fruit growth and yield has necessitated research into its trace level determination and estimation in harvested product. The phytohormone has ...increased the tomato yield (tonne ha
−1
) up to 24.7% with uniform fruit shape, size colour and lustre. A fast, simple, high-throughput analytical method was standardised based on electrospray ionisation — liquid chromatography-tandem mass spectrometry (LC–MS/MS). The samples were extracted using acidified (1% formic acid) methanol. The method was validated as per the SANTE/12682/2019 guidelines. The limits of detection (LOD) and quantification (LOQ) were 0.01 and 0.05 mg kg
−1
. The average recoveries at LOQ and higher levels were in the range of 86–108% with relative standard deviation (RSD) < 20%. The validated method was successfully applied under field condition by following first-order kinetics with half-lives (T
1/2
) 1.76 days (recommended dose) and 1.99 days (double dose). The estimated pre-harvest intervals (PHIs) were 6 days (recommended dose) and 8 days (double dose). Studies on dietary risk assessment concluded that even after spray of GA
3
at recommended dose, the harvested produce (tomato) could be consumed safely.
We report on an analysis of XMM-Newton data from the neutron star low-mass X-ray binary (LMXB) Serpens X-1 (Ser X-1). Spectral analysis of EPIC PN data indicates that the previously known broad iron ...K alpha emission line from this source has a significantly skewed structure with a moderately extended red wing. The asymmetric shape of the line is well described with the laor and diskline models in XSPEC and strongly supports an inner accretion disk origin of the line. To our knowledge, this is the first strong evidence of a relativistic line in a neutron star LMXB. This finding suggests that the broad lines seen in other neutron star LMXBs likely originate from the inner disk as well. Detailed study of such lines opens up a new way to probe neutron star parameters and their strong gravitational fields. The red wing of the iron line from Ser X-1 is not as broad as that observed from some black hole systems. This is not unreasonable for a neutron star system, as the accretion disk has to terminate at or before the hard stellar surface. Finally, the inferred source inclination angle in the approximate range 40 degree -60 degree is consistent with the lack of dips and eclipses from Ser X-1.
In this article, a wind-driven doubly fed induction generator (DFIG), battery, and photovoltaic (PV) array-based system with advanced discrete second-order sequence filter-frequency locked loop ...control for grid-side converter (GSC) is presented. The improved grid-side control provides the reactive power demand of load connected at the point of common coupling. The GSC control provides active and reactive power sharing and mitigates the power quality issues at unbalanced and nonlinear load conditions. Moreover, it gives a satisfactory performance during the dynamic wind speeds and load variation. The maximum wind power is extracted using the tip speed ratio algorithm. The necessary quantity of reactive power for DFIG is delivered by the rotor-side converter (RSC). The battery with a bidirectional converter is connected to the common dc link of the DFIG. The battery is used to maintain the dc-link voltage between RSC and GSC and it stores the power in light-load conditions. It provides the load demand during lower wind speed and solar irradiation. The maximum solar power is extracted by well-established incremental conductance (InC) algorithm, which provides optimum performance during the high dynamic variation of solar irradiation. Moreover, the InC algorithm increases the system's stability and reduces costs. It is easy to implement and handle nonlinearity. The feedforward PV component is added with the active load current component to improve the dynamic behavior of the system. Simulated and test results show the performance of the developed system in different dynamic conditions, such as load unbalancing, changes in PV insolation, and change in speed from the cut-in to cut-out speeds of the wind turbine. Moreover, obtained results show the battery behavior during different dynamic conditions.
The γ-ray flare of PKS 1222+216, observed in 2010 June, is interpreted as an outcome of jet dynamics at recollimation zone. We obtained the γ-ray light curves in three different energy bands, namely ...100–300 MeV, 300 MeV–1 GeV and 1–3 GeV from observations by the Fermi-LAT (Large Area Telescope). We also use the Swift-XRT (X-Ray Telescope) flux from 0.3–10 keV obtained from archival data. We supplement these with the 0.07–0.4 TeV observations with MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescope, available in the literature. The detection of source at very high energy (E > 100 GeV) with a differential photon spectral index of 2.7 ± 0.3 and the rapid variability associated with it suggests that the emission arises from a compact region located beyond the broad line emitting region. The plausible γ-ray emission mechanism can then be inverse Compton scattering of IR photons from obscuring torus. Further, the decay time of LAT flare cannot be explained by considering simple radiative loss mechanisms. Hence, to interpret the LAT light curves, we develop a model where the broad-band emission originates from a compact region, arising plausibly from the compression of jet matter at the recollimation zone. The flare is then expressed as an outcome of jet deceleration probably associated with this focusing effect. Based on this model, the rise of the LAT flare is attributed to the opening of emission cone followed by the decay resulting from jet deceleration. The parameters of the model are further constrained by reproducing the broad-band spectral energy distribution of the source obtained during the flare episode. Our study suggests that the particle energy density exceeds magnetic energy density by a large factor which in turn may cause rapid expansion of the emission region. However, near equipartition can be achieved towards the end of LAT flare during which the compact emission region would have expanded to the size of jet cross-section.
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