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1.
Doklady Earth Sciences - Kaladgi rocks are very well exposed in Belgaum district of Karnatak state, with adjacent to Maharashtra state. The rocks exposed in the study area comprises mainly of... 相似文献
2.
K. M. Hiremath 《Journal of Astrophysics and Astronomy》2006,27(2-3):367-372
We use 130 years data for studying correlative effects due to solar cycle and activity phenomena on the occurrence of rainfall
over India. For the period of different solar cycles, we compute the correlation coefficients and significance of correlation
coefficients for the seasonal months of Jan–Feb (JF), Mar–May (MAM), June–Sept (JJAS) and Oct–Dec (OND) and,annual mean data. We find that: (i) with a moderate-to-high significance, Indian rainfall is correlated with the sunspot activity and,
(ii) there is an overall trend that during the period of low sunspot activity, occurrence of rainfall is high compared to
the period of high sunspot activity.
We speculate in this study a possible physical connection between the occurrence of the rainfall and the sunspot activities
and, the flux of galactic cosmic rays. Some of the negative correlations between the occurrences of the sunspot and rainfall
activities obtained for different solar cycle periods are interpreted as effects of aerosols on the rain forming clouds due
to either intermittent volcanic eruptions or due to intrusion of interstellar dust particles in the Earth’s atmosphere. 相似文献
3.
Mahantesh S. Hiremath Ranbir S. Sandhu Leslie W. Morland William E. Wolfe 《国际地质力学数值与分析法杂志》1988,12(2):121-139
Biot's dynamic equations of motion for one-dimensional wave propagation in a fluid-saturated linear elastic isotropic soil are solved using Laplace transformation followed by numerical inversion and the results compared with a direct finite element formulation. A soil column of finite dimension subjected to velocity boundary conditions is analysed, allowing for reflection of waves from boundaries. Comparison of time histories at given points along the column shows that the finite element solution gives good agreement with the Laplace transform solution for low as well as high drag. 相似文献
4.
We have used a high spatial and temporal resolution of long time sequence of spectra in CaII H-line obtained at the Vacuum
Tower Telescope (VTT) of the Sacramento Peak Observatory on a quiet region at the center of the solar disk over a large number
of bright points and network elements to search for atmospheric (chromospheric) g-mode oscillations. An important parameter
of the H-line profile, intensity at H2v(Ih2V), has been derived from a large number of line profiles. We derived the light curves of all the bright points and network
elements. The light curves represent the main pulse with large intensity amplitude and followed by several follower pulses
with lower intensity amplitudes. The light curves of these bright points would give an impression that one can as well draw
curves towards and away from the highest peak (main pulse) showing an exponential growth and decay of the amplitudes. An exponential
decaying function has been fitted for all the light curves of the bright points to determine the damping time of the modes
that are more or less the same, and one value of the coefficient of exponent can represent reasonably well the decay for all
the cases. The FFT analysis of temporal variation of both the bright points and the network elements indicates around 10-min
periodicity. We speculate that this longer period of oscillation may be related to chromospheric g-mode oscillations. 相似文献
5.
Ragadeepika?Pucha K.?M.?Hiremath Shashanka?R.?GurumathEmail author 《Journal of Astrophysics and Astronomy》2016,37(1):3
Sunspots are the most conspicuous aspects of the Sun. They have a lower temperature, as compared to the surrounding photosphere; hence, sunspots appear as dark regions on a brighter background. Sunspots cyclically appear and disappear with a 11-year periodicity and are associated with a strong magnetic field ( ~103 G) structure. Sunspots consist of a dark umbra, surrounded by a lighter penumbra. Study of umbra–penumbra area ratio can be used to give a rough idea as to how the convective energy of the Sun is transported from the interior, as the sunspot’s thermal structure is related to this convective medium.An algorithm to extract sunspots from the white-light solar images obtained from the Kodaikanal Observatory is proposed. This algorithm computes the radius and center of the solar disk uniquely and removes the limb darkening from the image. It also separates the umbra and computes the position as well as the area of the sunspots. The estimated results are compared with the Debrecen photoheliographic results. It is shown that both area and position measurements are in quite good agreement. 相似文献
6.
The effects of mass transfer on the flow of a viscous incompressible fluid past an impulsively started infinite vertical isothermal plate are studied. The non-linear coupled equations governing the problem are solved by explicit finite-difference method. The presence of different gases like H2O, CO2, ete in air are considered. Velocity and temperature profiles are shown on graphs. The finite-difference results are compared with the results derived from the exact solution and they are found to agree well 相似文献
7.
K. M. Hiremath 《Astrophysics and Space Science》2008,314(1-3):45-49
In the previous study (Hiremath, Astron. Astrophys. 452:591, 2006a), the solar cycle is modeled as a forced and damped harmonic oscillator and from all the 22 cycles (1755–1996), long-term
amplitudes, frequencies, phases and decay factor are obtained. Using these physical parameters of the previous 22 solar cycles
and by an autoregressive model, we predict the amplitude and period of the present cycle 23 and future fifteen solar cycles. The period of present solar
cycle 23 is estimated to be 11.73 years and it is expected that onset of next sunspot activity cycle 24 might starts during
the period 2008.57±0.17 (i.e., around May–September 2008). The predicted period and amplitude of the present cycle 23 are almost similar to the period
and amplitude of the observed cycle. With these encouraging results, we also predict the profiles of future 15 solar cycles.
Important predictions are: (i) the period and amplitude of the cycle 24 are 9.34 years and 110 (±11), (ii) the period and
amplitude of the cycle 25 are 12.49 years and 110 (±11), (iii) during the cycles 26 (2030–2042 AD), 27 (2042–2054 AD), 34
(2118–2127 AD), 37 (2152–2163 AD) and 38 (2163–2176 AD), the sun might experience a very high sunspot activity, (iv) the sun
might also experience a very low (around 60) sunspot activity during cycle 31 (2089–2100 AD) and, (v) length of the solar
cycles vary from 8.65 years for the cycle 33 to maximum of 13.07 years for the cycle 35. 相似文献
8.
9.
K. M. Hiremath M. R. Lovely R. Kariyappa 《Journal of Astrophysics and Astronomy》2006,27(2-3):333-338
The positional measurements of sunspots from the Kodaikanal Observatory and Solar Geophysical data are used to study the association
between occurrence of the abnormal activities of big sunspot groups that were observed during the period of October–November
2003 and occurrence of the flares. During the evolution of the sunspot groups, we have investigated the temporal variations
in (i) areas; (ii) rotation rates; (iii) longitudinal extents; and (iv) number of small spots produced in a sunspot group.
Among all these activity variations, we find that the spot groups that experience abnormal rotation rates during their evolutionary
phases eventually trigger the flares. 相似文献
10.
Shashanka R. Gurumath K. M. Hiremath V. Ramasubramanian 《Journal of Astrophysics and Astronomy》2017,38(2):19
By considering the physical and orbital characteristics of G type stars and their exoplanets, we examine the association between stellar mass and its metallicity that follows a power law. Similar relationship is also obtained in case of single and multiplanetary stellar systems suggesting that, \(\hbox {Sun}^{\prime }\)s present mass is about 1% higher than the estimated value for its metallicity. Further, for all the stellar systems with exoplanets, association between the planetary mass and the stellar metallicity is investigated, that suggests planetary mass is independent of stellar metallicity. Interestingly, in case of multiplanetary systems, planetary mass is linearly dependent on the stellar absolute metallicity, that suggests, metal rich stars produce massive (\(\ge \)1 Jupiter mass) planets compared to metal poor stars. This study also suggests that there is a solar system planetary missing mass of \({\sim }\)0.8 Jupiter mass. It is argued that probably 80% of missing mass is accreted onto the Sun and about 20% of missing mass might have been blown off to the outer solar system (beyond the present Kuiper belt) during early history of solar system formation. We find that, in case of single planetary systems, planetary mass is independent of stellar metallicity with an implication of their non-origin in the host star’s protoplanetary disk and probably are captured from the space. Final investigation of dependency of the orbital distances of planets on the host stars metallicity reveals that inward migration of planets is dominant in case of single planetary systems supporting the result that most of the planets in single planetary systems are captured from the space. 相似文献