Birkhoff’S Theorem In The Einstein–Cartan–Kalb–Ramond Theory Of Gravity     

F.?RahamanEmail author  R.?Mukherji  R.?Mondal 《Astrophysics and Space Science》2005,299(3):239-243

It is shown that an analog of Birkhoff’s theorem of general relativity exists in the Einstein–Cartan–Kalb–Ramond (ECKR) theory of gravity when Kalb–Ramond (KR) field strength, which occurs in the theory is independent of time.  相似文献   

Potato varietal discrimination using ground based multiband radiometer     

U. P. Shahi  Suman Kumar  N. P. Singh  A. K. Chaubey  Yogesh Kumar 《Journal of the Indian Society of Remote Sensing》2007,35(1):53-65

The potential usefulness of spectral properties and vegetation indices in varietal discrimination of potato genotypes was studied in the field experiment. Spectral measurements were recorded in different bands in blue (450–520 nm), green (520–590 nm), red (620–680 nm) and infrared (770–860 nm) of the electromagnetic spectrum at different stages during crop growth period. A ground based hand held multiband radiometer (Model/041) was used for the purpose. The mean per cent green reflectance value among different genotypes was lowest in genotype MS/86-89, while it was observed highest in genotype JX-216. Significant difference among these genotypes was found at all growth stages except 6 week after planting. Consequent to variation in spectral reflectance the vegetation indices like, NDVI, RVI, TVI and DVI showed significant difference among genotypes at all growth stages except at 8^th week after planting. The vegetation indices are good indicators of crop growth and condition. Similarly, fresh weight, dry weight, and leaf area index were also highest in MS/86-89, followed by KUFRI Bahar and KUFRI Sutlej while in case of leaf area index it was followed by Kufri Sutlej and Kufri Bahar. JX-23 was highest in chlorophyll content and tuber yield followed by MS/86-89 and JW-160, while lowest chlorophyll content was seen in MS/89-1095 and poorest tuber yield in MS/89-60. Most of the genotypes exhibited considerable variation in their spectral response and vegetation indices thereby indicating the possibility of their discrimination through remote sensing technique.  相似文献   

Mechanical sources in orthotropic micropolar continua     

Rajneesh Kumar  Suman Choudhary 《Journal of Earth System Science》2002,111(2):133-141

The present paper is concerned with the problem of an orthotropic micropolar half-space subjected to concentrated and distributed loads. The disturbance due to normal and tangential loads are investigated by employing eigen-value approach. The integral transforms have been inverted by using a numerical technique to obtain the normal displacement, normal force stress and tangential couple stress in the physical domain. The results of these quantities are given and illustrated graphically.  相似文献   

Some rain rate and rain attenuation statistics at millimeter wavelengths in the tropics     

N. C. Mondal  A. B. Bhattacharya  S. K. Sarkar  R. Bhattacharya  A. K. Sen 《Theoretical and Applied Climatology》1996,54(3-4):229-234

Summary A study of rain rate and rain induced attenuation characteristics over two tropical stations in India has been made. The observed rain rate distributions differ significantly when compared with the CCIR report. The refractive indices have been calculated for certain frequencies at a tropical rain temperature of 20°C showing the variational pattern at different millimeter wavelengths. The present analysis also reveals that in the range 0.05 cm–0.3 cm drop diameter the variations of scattering amplitudes are systematic while in the range 0.4 cm–0.6 cm they are irregular.With 6 Figures  相似文献   

A comparison of two techniques for calculating groundwater arsenic-related lung,bladder and liver cancer disease burden using data from Chakdha block,West Bengal     

Debapriya Mondal  George C.D. Adamson  Ross Nickson  David A. Polya 《Applied Geochemistry》2008

Calculation of excess disease burden for As exposed populations is becoming increasingly important to enable quantitative estimation of the impacts of various As mitigation options. There are several methods by which such calculations may be carried out. In this study, two methods, recently applied to estimating groundwater As-related health risks in southern Asia, to estimate disease burden arising from lung, bladder and liver cancer from As exposure for an As-effected area of West Bengal have been compared. Both utilized calculated distributions of exposure of the studied population to As from groundwater. Method (I) then entailed calculating disease burden by combining published background rates for death and disability adjusted life years (DALYs) and standard mortality ratios (SMRs) for excess health impacts related to As exposure, whilst for Method (II), disease burden from As exposure was estimated using the basic DALY formula, combined with incidence rates based on the NRC multistage Weibull model. Dose–response data for both methods were based on studies in Taiwan.  相似文献   

Major ion chemistry,weathering processes and water quality assessment in upper catchment of Damodar River basin,India   总被引：5，自引：0，他引：5  

Abhay Kumar Singh  G. C. Mondal  Suresh Kumar  T. B. Singh  B. K. Tewary  A. Sinha 《Environmental Geology》2008,54(4):745-758

The chemical characteristics of surface, groundwater and mine water of the upper catchment of the Damodar River basin were studied to evaluate the major ion chemistry, geochemical processes controlling water composition and suitability of water for domestic, industrial and irrigation uses. Water samples from ponds, lakes, rivers, reservoirs and groundwater were collected and analysed for pH, EC, TDS, F, Cl, HCO₃, SO₄, NO_3, Ca, Mg, Na and K. In general, Ca, Na, Mg, HCO₃ and Cl dominate, except in samples from mining areas which have higher concentration of SO₄. Water chemistry of the area reflects continental weathering, aided by mining and other anthropogenic impacts. Limiting groundwater use for domestic purposes are contents of TDS, F, Cl, SO₄, NO₃ and TH that exceed the desirable limits in water collected from mining and urban areas. The calculated values of SAR, RSC and %Na indicate good to permissible use of water for irrigation. High salinity, %Na, Mg-hazard and RSC values at some sites limit use for agricultural purposes.  相似文献   

A diagnosis of groundwater quality from a semiarid region in Rajasthan,India     

N. C. Mondal  K. K. Tiwari  K. C. Sharma  S. Ahmed 《Arabian Journal of Geosciences》2016,9(12):602

A diagnosis of the groundwater quality of 70 wells sampled during two climatic regimes (dry and raining seasons) from a semiarid area in Rajasthan, India, had been carried out using standard methods. Analysis of the results for various hydrochemical parameters wherein the geological units are alluvium, quartzite and granite gneisses showed that all the parameters did not fall within the World Health Organisation’s acceptable limits for irrigation and drinking water purposes. The order of major cations and anions obtained during the dry and raining seasons are Na⁺ ? Mg²⁺ ? Ca²⁺ ? K⁺ and Cl^?? HCO₃ ^? ? SO₄ ^2?? CO₃ ^?> F^? ? NO₃ ^?, respectively. A maximum value of nitrate of 491.6 mg/l has been examined and its contamination is due to discriminated highly impacted groundwater samples by agricultural activity and small-scale urbanization. Fluoride (F^?) concentration is 6.50 mg/l as a maximum value, whereas values in about 26 % of the samples are more than the permissible limit (1.5 mg/l) for drinking water. The cumulative probability distributions of the selected ions show two individual intersection points with three diverse segments, considered as regional threshold values and highly impacted threshold values for differentiating the samples with the effects of geogenic, anthropogenic and saline water mixing. The first threshold values indicate the background hydrochemical constituents in the study area. The second threshold value of 732 mg/l for bicarbonate indicates that sandy aquifer is being dissolved during wet period, whereas NO₃ ^? concentration of more than the initial threshold value (=75 mg/l) indicates discriminated highly impacted groundwater samples by agricultural activity and urbanization in dry season. Various parameters such as soluble sodium percentage (SSP), salinity (electrical conductivity (EC)), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), Kelley’s ratio (KR), permeability index (PI), residual sodium bicarbonate (RSB) and magnesium absorption ratio (MAR) for the well samples show that, overall, 46 % of groundwater samples are not suitable for irrigation. Further, chloro-alkaline indices (CAIs) were used for distinguishing regional recharge and discharge zones whereas corrosivity ratio (CR) utilized for demarcating areas to use metallic pipes for groundwater supply. In general, groundwater quality is mainly controlled by the chemical weathering of rock-forming minerals. The information obtained represents a base for future work that will help to assess the groundwater condition for periodical monitoring and managing the groundwater from further degradation.  相似文献   

Spatio-temporal variability of lightning climatology and its association with thunderstorm indices over India     

Mondal  Unashish  Panda  S. K.  Das  Someshwar  Sharma  Devesh 《Theoretical and Applied Climatology》2022,149(1-2):273-289

Theoretical and Applied Climatology - Lightning is an electrical discharge — a ‘spark’ or ‘flash’ as charged regions in the atmosphere instantly balance themselves...  相似文献   

Temporal variability in the withdrawal phase of southwest monsoon over India and related consequences in northeast monsoon: a climatological perspective     

Mondal  Paramita  Chaudhuri  Sutapa 《Theoretical and Applied Climatology》2022,148(3-4):1021-1034

Theoretical and Applied Climatology - The variability in duration of withdrawal phase of southwest monsoon over India is often witnessed to influence the northeast monsoon rainfall of India as...  相似文献   

Mapping lithology and assessing recharge characteristics in a granitic hard rock aquifer: Inference from 2D resistivity,induced polarization,tracer and moisture measurements     

Dewashish Kumar  G. B. K. Shankar  Setbandhu Mondal  V. Venkatesam  K. Sridhar  P. N. Rao  Pandith Madhnure  R. Rangarajan 《Journal of the Geological Society of India》2016,88(1):29-38

Two dimensional Electrical Resistivity Tomography (ERT) investigation along with Time Domain Induced Polarization (TDIP) investigation covering 1.6 km line were carried out at 3 natural recharge sites in a overexploited groundwater granite watershed, situated in a semi arid region in the state of Telangana, India. At these sites, shallow and/ or deep moisture influx measurements were also carried out using injected tritium tracer and neutron moisture probe. The watershed is covered by sandy loam to silt loam soil, receives an average annual rainfall of 620 mm with the pre monsoon groundwater level ranging from 8m to 29m bgl. The spot investigations were done to assess and understand the recharge process and groundwater potential in terms of resistivity/conductivity and moisture characteristics of the subsurface rock formation.  相似文献