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71.
Kumar Gulshan Bhadwal Reetika Kumar Mukesh Kumari Punam Kumar Arvind Walia Vivek Mehra Rohit Goyal Ayush 《Natural Hazards》2022,111(3):2219-2240
Natural Hazards - This work reports radon-thoron monitoring at two depths (60 and 90 cm) and at 82 sites around Jawalamukhi thrust of NW Himalaya, India using Solid State Nuclear Track... 相似文献
72.
73.
The study of surface wave in a layered medium has their possible application in geophysical prospecting. In the present work, dispersion equation for torsional wave in an inhomogeneous isotropic layer between inhomogeneous isotropic half‐spaces has been derived. Two cases are discussed separately for torsional wave propagation in inhomogeneous layer between homogeneous and non‐homogeneous half‐spaces, respectively. Further, two possible modes for torsional wave propagation are obtained in case of inhomogeneous layer sandwiched between non‐homogeneous half‐spaces. Closed form solutions for displacement in the layer and half‐spaces are obtained in each case. The study reveals that the layer width, layer inhomogeneity, frequency of inhomogeneity, as well as inhomogeneity in the half‐space has significant effect on the propagation of torsional surface waves. Displacement and implicit dispersion equation for torsional wave velocities are expressed in terms of Heun functions and their derivatives. Effects of inhomogeneity on torsional wave velocity are also discussed graphically by plotting the dimensionless phase velocity against dimensionless and scaled wave number for different values of inhomogeneity parameter. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
74.
In this research paper, we have derived the formula for both the changes in energy (δE) and entropy (δS) and thereafter calculated the change in entropy (δS) with corresponding change in energy (δE) taking account the first law of the black hole mechanics relating the change in mass M, angular momentum J, horizon area A and charge Q, of a stationary black hole, when it is perturbed, given by formula satisfying in the vacuum as
dM = \frack8p dA + WdJ - udQ\delta M = \frac{k}{8\pi} \delta A + \Omega\delta J - \upsilon\delta Q, specially for Non-spinning black holes. 相似文献
75.
Ranjit?Kumar Abha?Rani K.?Maharaj?Kumari S.?S.?SrivastavaEmail author 《Journal of Atmospheric Chemistry》2005,50(3):243-261
This paper presents dry deposition flux and deposition velocity of atmospheric particles on white marble and red stone at Dayalbagh, a suburban site of semi arid region, which is 10 km away from the industrial sector of the Agra city where due to agricultural practices vegetation predominates. The wind speed at Agra is mostly in the range of 1–2 m s–1. The atmospheric calm conditions at Agra in summer, monsoon, and winter seasons are 47%, 35%, and 76%, respectively. Industrial areas of the city are away from Dayalbagh and are located in the NE, E, SE, and SW sectors. The main industrial activities, which are in operation in Agra city and its outskirts, are foundry and forging industry. The other industrial activities in Agra are rubber processing, lime oxidation and pulverization, chemicals, engineering and brick refractory kilns. Dry deposition samples were collected on dry days on white marble and red stone (0.224 m × 0.224 m × 0.02 m) using surface washing method. Both slabs were fixed to an iron stand (1.5 m height) at an angle of about 80 from the horizontal and exposed for 24 h on the roof of the faculty building. The order of deposition flux on white marble is NH4+ > Mg2+ > Ca2+ > Na+ > Cl– > K+ > NO3– > SO42– > F– and that on red stone is NH4+ > Mg2+ > Ca2+ > SO42– > Na+ > NO3– > K+ > F– > Cl–. Average dry deposition flux of major ions varies from 3.4 to 128.5 M m–2 d–1. The sum of major cations on white marble and red stone are 516.4 and 450.4 eq m–2 d–1, respectively while sum of major anions are 425.3 and 400.4 eq m–2 d–1 on white marble and red stone, respectively. Higher deposition of all ions was observed when wind blows from NE as most of the Agra Iron foundries and Ferozabad glass industries lie in this direction. The mean values of dry deposition velocity of ions vary between 0.22 cm s–1 to 1.49 cm s–1. Deposition velocity for all ions is higher on white marble than red stone inspite of rougher surface of red stone as compared to white marble. This could be due to the chemical nature of white marble, which is made of dolomite and hence adds significant amount of ions by dissolution during washing. Seasonally the deposition velocity was highest in winter. 相似文献
76.
Recent observations indicate that the primordial abundance of4He could be smaller than 0.24. It may then be necessary to invoke neutrino degeneracy in the early universe to explain the primordial abundances of helium and deuterium. It is shown here that the necessary degeneracy, though small, gives rise to a large asymmetry between the present number densities of neutrinos and antineutrinos. The effect of degeneracy on the upper limit to the neutrino masses is also considered. 相似文献
77.
The population of the rotational levels of vibrational and electronic ground state of interstellar H2 has been calculated; different possible excitation and de-excitation mechamisms including the ultraviolet pumping and formation and destruction of molecules have been considered. The values of temperature, density and radiation field towards ζ Oph, ? Per and ζ Pup have been obtained by comparing the theoretical distributions with the observations. The results indicate the presence of a high temperature low density diffuse cloud towards ζ Pup and low temperature high density clouds towards ζ Oph and ? Per. The results of this work were presented at the February, 1974 meeting of the Astronomical Society of India (Joshi and Tarafdar, 1974). 相似文献
78.
Ranjit Kumar Abha Rani S. P. Singh K. Maharaj Kumari S. S. Srivastava 《Journal of Atmospheric Chemistry》2002,41(3):265-279
Rainwater samples were collected for the monsoon period of 1988 and 1991–1996 at Dayalbagh (Agra), a suburban site situated in semiaridregion. The mean pH was 7.01 ±1.03 well above 5.6, which is the reference pH. Concentration of Ca2+ was observed to be highest followed by Mg2+, NH4
+,SO4
2–, Cl–,NO3
–, Na+, F– and K+. The ratios of SO4
2– + NO3
– andCa2+ + Mg2+ (TA/TC) have been considered as indicatorfor acidity. In the Agra region ratio of TA/TC is quite below 1.0 indicating alkaline nature of rainwater. The lowest value of 0.24 was observed in 1991 likely due to the lowest rain depth of the decade. The highest value of 0.54 was observed in 1996, a year with a large rain depth and increase in line (vehicular traffic) and area sources (population growth). Good correlation between Ca2+ and NO3
–,Ca2+ and SO4
2– andSO4
2– and NO3
–,indicates that wind carried dust and soil play a significant role in neutralization of precipitation acidity. 相似文献
79.
Nandini Kumar U. C. Kulshrestha A. Saxena P. Khare K. M. Kumari S. S. Srivastava 《Journal of Atmospheric Chemistry》1996,23(1):81-87
A total of 59 rainwater samples were collected during the winter and monsoon (1991–92) at Dayalbagh, Agra. This site is relatively free from the influence of anthropogenic emissions and the volume-weighted average concentrations (VWA) of formate in the winter and monsoon were 22.5±6, 16.1±3 while acetate VWAs were 17.1±5 and 13.8±3 mol l-1, respectively. Although the VWAs varied between seasons, it was not statistically different. Total deposition (in mmol m-2) varied between season (winter formate, 1.4; acetate, 1.1; monsoon formate, 7.4; acetate, 6.4). A difference in VWA values may have occurred as a result of the dilution factor; the total rain depth from collected samples in the monsoon was 46 cm while that in winter was 6.3 cm. Sources at this site may be anthropogenic and natural; scavenging from the vapour phase, washout of soil particles and emissions from vegetative sources are probably important sources for formate and acetate. 相似文献
80.
Atmospheric particle-bound mercury levels were measured in PM10 aerosols (HgP) at a rural site (Mahasar, Haryana) during winter 2014–15 and summer 2015. The PM10 HgP was determined by using Differential Pulse Anodic Stripping Voltammetry through standard addition methods while the trace metals were determined by using an Atomic Absorption Spectroscopy. The mass concentrations of HgP varied from 591 to 1533 pg/m3 with an average of 1009?±?306 pg/m3 during the winter, while the mass concentrations of HgP varied from 43 to 826 pg/m3 with an average of 320?±?228 pg/m3 during the summer. However, it is difficult to assess whether these levels are harmful or not because there is no standard value available as National Ambient Air Quality Standard. The higher concentrations of HgP during winters were possibly due to favourable local meteorological conditions for the stagnation of particulate matter in the lower atmosphere and the increased emissions from existing natural or anthropogenic sources, regional sources and long-range transportation. Relatively low concentrations of HgP during summer might be due to increased mixing heights as well as scavenging effect because some light to heavy rain events were observed during summer time sampling. However, among other metals determined, the concentration of HgP was the lowest during both the seasons. The study may be useful in assessing the health impacts of PM10 HgP and other metals. 相似文献