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In this paper, we have studied the magnetized quark matter (QM) and strange quark matter (SQM) distributions in the presence of \(f(R,T)\) gravity in the background of Friedmann-Lemaître-Robertson-Walker (FLRW) metric. To get exact solutions of modified field equations we have used \(f(R,T ) = R + 2 f(T)\) model given by Harko et al. with two different parametrization of geometrical parameters i.e. the parametrization of the deceleration parameter \(q \), and the scale factor \(a \) in hybrid expansion form. Also, we have obtained Einstein Static Universe (ESU) solutions for QM and SQM distributions in \(f(R,T)\) gravity and General Relativity (GR). All models in \(f(R,T)\) gravity and GR for FRW and ESU Universes with QM also SQM distributions, we get zero magnetic field. These results agree with the solutions of Akta? and Aygün in \(f(R,T)\) gravity. However, we have also discussed the physical consequences of our obtained models. 相似文献
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Nagpal Anushree Hassan Mohammad Siddiqui Masood Ahsan Tajdar Atiqua Hashim Mohammad Singh Abhra Gaur Suman 《GeoJournal》2021,86(2):649-661
GeoJournal - Sanitation is a multidimensional concept alluding primarily to provision of services for safe disposal of human excreta, provision of clean potable water as well as maintenance of... 相似文献
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Summary Uranium concentration in feldspar, pyroxene and carbonate groups of minerals has been studied by using the induced fission track technique. Fractions of homogeneously and heterogeneously distributed uranium have been estimated by differential counting. The suitability of studied minerals for fission track geochronology is discussed. 相似文献
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P. Kamatchi J. Rajasankar Nagesh R. Iyer N. Lakshmanan G.V. Ramana A.K. Nagpal 《Soil Dynamics and Earthquake Engineering》2010
Towards formulating guidelines for performance evaluation of buildings to site-specific earthquakes, studies are reported in literature on the effect of various critical parameters. No study is, however, reported on the effect of depth of soil stratum. In this paper, a methodology is proposed and applied for performance evaluation of buildings for site-specific earthquakes including depth of soil stratum as a parameter. The methodology integrates independent procedures meant for performance evaluation of buildings and site-specific seismic analysis. Application of the proposed methodology enables to determine performance point of a building in terms of inelastic displacement and base shear. Numerical application of the methodology is demonstrated using the particulars of Delhi region. Two typical RC buildings (B1 and B2) with significantly different inelastic behaviour, assumed to be located on soil depths ranging from 10 to 200 m are chosen for the application study. Capacity spectra of the buildings are generated from nonlinear static analysis. Studies indicate that for building B1, with elasto-plastic behaviour, the depth of soil stratum strongly influences demand on inelastic displacement compared to that on inelastic base shear. For building B2, with continuously varying inelastic behaviour, the depth of soil stratum is observed to have significant influence on both the inelastic base shear as well as inelastic displacement. Responses of the buildings are compared with that obtained based on design spectrum of Indian seismic code. For both the cases, inelastic displacements as well as inelastic base shears are underestimated by Indian seismic code for certain depths of soil stratum. Proposed methodology enables the calculation of realistic values of inelastic base shear and corresponding displacement of a building for site-specific earthquakes by considering the actual characteristics of soil stratum. 相似文献
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A general neural network based methodology that has the potential to replace the computationally-intensive site-specific seismic analysis of structures is proposed in this paper. The basic framework of the methodology consists of a feed forward back propagation neural network algorithm with one hidden layer to represent the seismic potential of a region and soil amplification effects. The methodology is implemented and verified with parameters corresponding to Delhi city in India. For this purpose, strong g... 相似文献
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Aruna Srivastava Corresponding author B. N. Nagpal Rekha Saxena Vas Dev S. K. Subbarao 《International journal of geographical information science》2013,27(1):91-98
This paper reports research to predict the distribution of An. minimus, a malaria vector in forest fringe areas using GIS to support precision surveys for malaria control. Because An. minimus is a forest‐associated species, generalized thematic maps (1:6?000?000) of forest cover, soil type, altitude, rainfall and temperature were used. Digitization, overlaying, integration and analysis of thematic maps were done using Arc/Info 8.1 NT and Arc/View 3.2 (GIS, ESRI) software. GIS delineated favourable areas for An. minimus where the species is likely to be found, and precision surveys can be conducted. Precision field surveys in selected locations of favourable/non‐favourable areas were carried out. The species could be found in all locations designated as a favourable area and was absent in non‐favourable areas. In two districts, one where the species is reported to have disappeared in the early 1950s and the other where it was not reported in earlier surveys, GIS helped in precision surveys, and An. minimus was found. The technique can quickly cover vast and inaccessible areas and is easy to duplicate in other parts of the world to assist cost‐effective control of malaria. It can also delineate areas favourable for any species of flora and fauna to help precision surveys. 相似文献
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R. Raghavarao R. Suhasini R. Sridharan B. V. Krishnamurthy O. P. Nagpal 《Journal of Earth System Science》1990,99(3):413-423
The equatorial wave campaign-II which formed a part of the Indian Middle Atmosphere Programme (IMAP), was conducted from SHAR
(13.7°N, 80.2°E) from 15 January to 28 February 1986. Winds were measured from ground to 60 km by means of high altitude balloon
and a meteorological rocket (RH-200), once everyday, for 45 days. The frequencies of the oscillations in the deviations of
the east-west component of the winds from its mean at each height with one kilometer interval were obtained by the maximum
entropy (ME) method and phases/amplitudes of these frequencies were determined by the least squares technique on the wind
variation time series. The ME method has the inherent advantage of providing periodicities up to 1.5 times the data length.
The height structure of the long period waves of > 23 day periodicities that have larger amplitudes nearly by a factor of
2 as compared to the medium (9 to 22 day) or shorter period (4 to 8 day) ones, reveal two height regions of enhanced amplitudes,
one in the troposphere and another in the upper stratosphere/lower mesosphere, that too, mostly in the regions of positive
(westerly increasing or easterly decreasing with height) wind shears. The waves are seen to be inhibited in the negative wind
shear regions. From the abrupt changes in the altitude variation of phase, the possible source region has been identified.
The vertical wavelengths have been estimated to be 34 km and 19 km in the troposphere and lower stratosphere respectively
and 8 km in the upper stratosphere and lower mesosphere. Around 56 km the wave amplitude is reduced to 1/4 of its value below,
while the vertical shear strength in the mean wind doubled up. The tropospheric waves are suggested to be Rossby waves of
extratropical origin penetrating to tropical latitudes. The stratospheric/mesospheric waves however appear to emanate from
a source around the stratopause. 相似文献
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Summary During the last phase of the Indian Middle Atmosphere Programme everyday launchings of high altitude balloons were carried out at three locations i.e. Trivandrum (8.5°N, 77.5°E), Hyderabad (17.2°N, 78.3°E) and Bhubaneshwar (21.3°N, 85.5°E) for measuring winds and temperature between 1 and 30 km altitude in a campaign mode from 23 January 1989 to 31 March 1989. The data thus obtained have been examined to determine the characteristics of tropical/equatorial waves. Spectral analysis of the time series (68 points) of both zonal and meridional wind components using Maximum Entropy Method (MEM) reveal the presence of waves with periods between 4–30 days.Strong oscillations centered around 5 days and 18 days seem to dominate in the upper troposphere and lower stratosphere at all the three stations. While 5 day wave has an amplitude of about 2 m/s, the 18 day wave has an amplitude between 8–10 m/s in the zonal and 5–6 m/s in meridional component around tropopause. Its amplitude is maximum over Hyderabad and decreases somewhat on either side i.e. over Trivandrum and Bhubaneshwar. Weekly rocket wind data from Balasore near Bhubaneshwar show that 18–20 day wave continues to propagate vertically in the altitude range of 30–60 km. Temperature data also exhibits similar oscillations with amplitude of about 1 K for 4–5 day wave and 2–3 K for 18 day wave maximising just above tropopause ( 18 km).It is found that some of the observed wave modes, particularly the 18 day wave have characteristics matching those of forced Rossby wave rather than Kelvin wave while the 5 day and 9 day waves have characteristics matching those of mixed Rossby-gravity waves. The latter may be generated due to convective forcing in the troposphere while the former may be penetrating from the midlatitudes.With 15 Figures 相似文献
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