Probabilistic modelling of joint orientation     

Pinnaduwa H. S. W. Kulatilake  Tien H. Wu  Deepa N. Wathugala 《国际地质力学数值与分析法杂志》1990,14(5):325-350

Observed frequencies of joint orientations are subject to error due to sampling bias. This error should be corrected before statistical inference is made on the distribution of orientation. Corrections (weighting functions) are developed for sampling bias in orientation for finite joints of different sizes and shapes intersecting rectangular exposures. Chi-square goodness-of-fit procedures available for hemispherical normal and bivariate normal distributions are modified to make them applicable for both raw data and data corrected for sampling bias. The aforementioned corrections and procedures were applied to a joint orientation cluster to study the effect of (a) joint orientation, (b) joint size and (c) joint shape, on the statistical distribution of the orientation. The influences of all these aforementioned factors were found to be significant. However, at present, joint sizes and shapes are not measured in field joint surveys. Therefore, it is suggested to make attempts to obtain joint sizes and shapes in field joint mapping surveys. Since the currently available probability distributions are not adequate to represent all joint orientation distributions, it is suggested either to look for new probability distributions or to develop procedures to use empirical distributions in modelling orientation distributions.  相似文献   

Study of the galactic cluster NGC 6823     

Ram Sagar  U. C. Joshi 《Astrophysics and Space Science》1981,75(2):465-472

PhotoelectricUBV magnitudes have been determined for 41 stars in NGC 6823. The reddening across the cluster field is determined and found that it varies fromE(B-V)=0.60 to 1.16 mag. The true distance modulus to the cluster is estimated at 12.7±0.3 mag. It is found that cluster stars are not co-equal in age.  相似文献   

Interstellar extinction towards open clusters and Galactic structure     

Y. C. Joshi 《Monthly notices of the Royal Astronomical Society》2005,362(4):1259-1266

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On the periodicities of sunspots and solar strong hard X-ray bursts     

V. K. Verma  G. C. Joshi 《Solar physics》1987,114(2):415-418

In the present investigation, we have carried out power spectrum analysis of sunspot number and great hard x-ray (GHXR) burst (equal to or greater than 10,000 counts per second) for a period of about 6 years. The GHXR bursts show a periodicity of about 155 days. On the other hand, sunspot numbers do not show any periodicity. The GHXR burst periodicity confirms the existence of a 152–158 days periodicity in the occurrence of solar energetic events. Further, the GHXR bursts are showing periodicity independently indicating that the GHXR bursts are a separate class of X-ray flares.  相似文献   

Village level crop inventory using remote sensing and field survey data     

R. P. Singh  V. N. Sridhar  V. K. Dadhwal  R. Jaishankar  M. Neelkanthan  A. K. Srivastava  G. D. Bairagi  N. K. Sharma  S. A. Raza  Rajesh Sharma  Manoj Yadav  F. K. Joshi  N. L. Purohit 《Journal of the Indian Society of Remote Sensing》2005,33(1):93-98

This paper presents results of a pilot study in six villages located in the states of Haryana, Rajasthan and Madhya Pradesh, to evaluate accuracy of crop area at village level estimated by IRS - LISS-I1I data with respect to detailed field survey carried out by National Sample Survey Organization. The selected villages were located in Karnal, Kota and Bhopal districts which represented single dominant wheat crop as well as wheat-mustard and wheat-gram situation, respectively. Accuracy assessment of remote sensing based estimate with field survey of NSSO showed relative deviation in wheat estimate ranging from 3.72 percent for Mainmati village in Karnal district in Haryana to 22.65 percent fo Ranpur village in Kota district of Rajasthan. It was found that relative deviation in area estimation is inversely poportional to the crop proportion in that village. Observations of over estimation at low crop proportion and underestimation at higher crop proportion was explained by simple budgeting of relative proportion of ommision and commision errors. The study demonstrates that on the average, 90 percent crop area accuracy is possible with LISS-II1 data and the adopted approach.  相似文献   

The effect of ship scrapping industry and its associated wastes on the biomass production and biodiversity of biota in in situ condition at Alang     

Tewari A  Joshi HV  Trivedi RH  Sravankumar VG  Raghunathan C  Khambhaty Y  Kotiwar OS  Mandal SK 《Marine pollution bulletin》2001,42(6):462-469

The main pollutants for the ship scrapping industry and its associated wastes at Alang are heavy metals, petroleum hydrocarbon and bacterial contaminations. The concentration of iron, manganese, cobalt, copper, zinc, lead, cadmium, nickel and mercury were 25 to 15,500% more at nearshore station of Alang as compared to control site at Piram. The concentration of heavy metals in the nearshore station of Alang was always higher than its concentration at 10 km away. The concentration of petroleum hydrocarbon was 16,973 and 53,900% more at the nearshore and 10 km away respectively at Alang as compared to controls. The concentration of chlorophyll-a and phaeophytin were in non-detectable range (< 0.2 and < 0.1 mg m3) or much lower concentration at both the stations of Alang as compared to controls. The total viable count, total coliform, Escherichia coli, Vibrio cholerae, Vibrio parahaemolyticus and other Vibrio, Streptococcus faecalis, Shigella, Salmonella, Proteus, and Klebsiella were always higher (17%-605%) at the nearshore station of Alang as compared to control. Similar trend was observed at 10 km away from Alang. Bacteria in sediment also showed the same pattern of variation. Phytoplankton counts at the nearshore station and 10 km away from Alang were only slightly raised. In contrast to phytoplankton, the zooplankton showed considerable reduction of growth (-10 to -66%) at Alang.  相似文献   

Subsurface profiling of granite pluton using microtremor method: southern Aravalli,Gujarat, India     

Joshi  Aditya U.  Sant  Dhananjay A.  Parvez  Imtiyaz A.  Rangarajan  Govindan  Limaye  Manoj A.  Mukherjee  Soumyajit  Charola  Mitesh J.  Bhatt  Meghnath N.  Mistry  Sagar P. 《International Journal of Earth Sciences》2018,107(1):191-201

International Journal of Earth Sciences - We report, using the microtremor method, a subsurface granitic pluton underneath the Narukot Dome and in its western extension along a WNW profile, in...  相似文献   

Neoproterozoic siliciclastic sedimentation around Kampa-Tenpa area,Pranhita Godavari Graben (PGG), Central India: Facies analysis,petrography and depositional environment     

Y. A. Murkute  S. P. Joshi 《Journal of the Geological Society of India》2014,83(4):423-432

The Pranhita-Godavari Graben (PGG) represents a major lineament in south Indian Peninsular cratonic province, which preserves a thick column of sediments. In geological time scale, these sedimentary units correspond to Mesoproterozoic to Mesozoic period. The Mesoproterozoic sedimentation has been confined mainly to southern part of the PGG, while Neoproterozoic sediments are exposed at northern tip of the graben. In the area of investigation siliciclastic sedimentation units are exposed, wherein five major lithofacies have been marked out. These lithofacies are i) breccia (Br), ii) large scale trough cross-bedded sandstone (Ls), iii) small-scale trough cross-bedded sandstone (Sss), iv) horizontal bedded sandstone (Hs) and v) ripple laminated sandstone (Rs). The amalgamation of these lithofacies strongly divulges that the lower part of the succession was deposited in braided-streams, whereas the upper part was deposited in erg environment. The unimodal paleocurrent is evident in lower part of the succession while bimodal paleocurrent is noticed from sandstones at upper part of the succession. In general, the sandstones exhibit northwesterly paleocurrent direction. The petrographic studies point out that the sandstones are arenites and were deposited in interior type of continental block provenance under semi-arid to hot humid palaeoclimate. The high percentage of floating grains and the low percentage of interpenetrative contacts as well as the low value of contact index for these sandstones divulge that the grains did not suffer much compaction thereby pointing to shallow burial. The sub-angular zircon and tourmaline suggest that these minerals have travelled short distance from the source rocks. The high percentage of garnet and presence of epidote, staurolite, sillimanite, zoisite, amphibole and kyanite indicate that the sediments were derived from the nearby metamorphic source rocks.  相似文献   

Relationship between interplanetary field/plasma parameters with geomagnetic indices and their behavior during intense geomagnetic storms     

Navin Chandra Joshi  Neeraj Singh Bankoti  Seema Pande  Bimal Pande  Kavita Pandey 《New Astronomy》2011,16(6):366-385

This paper presents a correlative study between the peak values of geomagnetic activity indices (Dst, Kp, ap and AE) and the peak values of various interplanetary field (Bt, Bz, E and σ_B) and plasma (T, D, V, P and β) parameters along with their various products (BV, BzV and B²V) during intense geomagnetic storms (GMSs) for rising, maximum and decay phases as well as for complete solar cycle 23. The study leads to the conclusion that the peak values of different geomagnetic activity indices are in good correlation with Bt, Bz, σ_B, V, E, BV, BzV and B²V, therefore these parameters are most useful for predicting GMSs and substorms. These parameters are also reliable indicators of the strength of GMSs. We have also presented the lag/lead time analysis between the maximum of Dst and peak values of geomagnetic activity indices, various interplanetary field/plasma parameters for all GMSs. We have found that the average of peak values of geomagnetic activity indices and various field/plasma parameters are larger in decay phase compare to rising and maximum phases of cycle 23. Our analyses show that average values of lag/lead time lie in the ≈?4.00 h interval for Kp, ap and AE indices as well as for Bt, Bz, σ_B, E, D and P. For a more meaningful analysis we have also presented the above study for two different groups G1 (CME-driven GMSs) and G2 (CIR-driven GMSs) separately. Correlation coefficients between various interplanetary field/plasma parameters, their various products and geomagnetic activity indices for G1 and G2 groups show different nature. Three GMSs and associated solar sources observed during three different phases of this solar cycle have also been studied and it is found that GMSs are associated with large flares, halo CMEs and their active regions are close to the solar equator.  相似文献