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1.
A simply defined, accurate and efficient criterion of selecting a spectral-band combination for improved land use/land cover classification using remote sensing data is discussed. Results indicate that Brightness Value Overlapping Index (BVOI) is very effective in measuring the degree of overlap in brightness values among land cover types and in selecting suitable spectral-band combination for landuse classification. The results of BVOI are also compared with the results of another band-combination selecting index - Optimum Index Factor (OIF). 相似文献
2.
In recent earthquakes in developing countries, severe damage was observed on reinforced concrete buildings. This study focuses on exterior beam-column joints with substandard beam rebar anchorage and seismic strengthening by installing wing walls. First, a series of experiments was conducted to investigate the seismic behavior of exterior joints with substandard beam rebar anchorage representing typical Bangladeshi buildings. Two 0.7-scaled exterior joint specimens were tested, and these specimens showed beam rebar anchorage failure and/or joint shear failure. Prior to strengthening of the joint, a series of pullout tests was conducted on postinstalled bonded anchors in low-strength concrete for strengthening design. Then, an experiment was performed to apply the strengthening method by wing walls to one of the exterior joint specimens to improve the integrity, and this method was intended to prevent the failure of beam rebar anchorage. The strengthening method is proposed to extend the development length of beam longitudinal bars by considering the embedment length along the wing walls. The test results verified the effectiveness and applicability of the proposed strengthening method to upgrade exterior RC beam-column joints with deficient beam rebar anchorage. 相似文献
3.
Susanta Mahato Swades Pal Swapan Talukdar Tamal Kanti Saha Parikshit Mandal 《地学前缘(英文版)》2021,12(5):110-123
The flood hazard management is one of the major challenges in the floodplain regions worldwide. With the rise in population growth and the spread of infrastructural development, the level of risk has increased over time.Therefore, the prediction of flood susceptible area is a key challenge for the adoption of management plans.Flood susceptibility modeling is technically a common work, but it is still a very tough job to validate flood susceptible models in a very rigorous and scientific manner. Therefore, the present work in the Atreyee River Basin of India and Bangladesh was planned to establish artificial neural network(ANN), radial basis function(RBF), random forest(RF) and their ensemble-based flood susceptibility models. The flood susceptible models were constructed based on nine flood conditioning parameters. The flood susceptibility models were validated in a conventional way using the receiver operating curve(ROC). To validate the flood-susceptible models, a two dimensional(2 D) hydraulic flood simulation model was developed. Also, the index of flood vulnerability model was developed and applied for validating the flood susceptible models, which was a very unique way to validate the predictive models. Friedman test and Wilcoxon Signed rank test were employed to compare the generated flood susceptible models. Results showed that 11.95%–12.99% of the entire basin area(10188.4 km2) comes under very high flood-susceptible zones. Accuracy evaluation results have shown that the performance of ensemble flood susceptible models outperforms other standalone machine learning models. The flood simulation model and IFV model were also spatially adjusted with the flood susceptibility models. Therefore, the present study recommended for the ensemble flood susceptibility prediction and IFV based validation along with conventional ways. 相似文献
4.
Evaluation of Composts from Agricultural Wastes with Fish Pond Sediment as Bulking Agent to Improve Compost Quality 总被引:1,自引:0,他引:1
Tanmoy Karak Pradip Bhattacharyya Ranjit Kumar Paul Tapati Das Subhrajit K. Saha 《洁净——土壤、空气、水》2013,41(7):711-723
Composts with five different ratios of agricultural wastes, viz. rice straw (RS), wheat straw (WS), potato plant (PP), and mustard stover (MS) were prepared with or without fish pond bottom sediment to investigate the compost maturity and their suitability for field application. The composting process was monitored through the changes in physico‐chemical parameters and germination index (GI) at every 7 days interval of the composting process. All the composts were dark brown and smelled like forest soil within 56 days of composting, which reflected its matured status. On the basis of the physico‐chemical parameters (bulk density: 0.84 g/cm3; pH 7.05; electrical conductivity: 3.52 mS/cm; cation exchange capacity:82.4 cmol/kg; total carbon:321.4 g/kg; total nitrogen: 16.9 g/kg; As: 6.8 mg/kg; Cd: 2.96 mg/kg; Cr: 29.6 mg/kg, Cu: 243.6 mg/kg; Hg: 0.019 mg/kg; Ni: 24.3 mg/kg; Pb: 62.1 mg/kg and Zn: 812 mg/kg) and GI (89–96%), it could be concluded that RS/WS/PP/MS, 1:1:2:1 v/v/v/v with fish pond sediment produced better compost in accordance with the Indian compost standard. Application of a combined randomized block design analysis revealed that there is a significant difference in the responses of the five composts, in relation to the time of composting. Hierarchical clustering algorithm was applied with a view to form homogeneous groups of five different composts on the basis of different physico‐chemical parameters. Therefore, the ratio of waste incorporation is an important decision for composting and addition of pond sediment can improve the quality of compost. 相似文献
5.
Mandal Prantik Srinagesh D. Vijayaraghavan R. Suresh G. Naresh B. Raju P. Solomon Devi Aarti Swathi K. Singh Dhiraj K. Srinivas D. Saha Satish Shekar M. Sarma A. N. S. Murthy YVVBSN 《Natural Hazards》2022,111(3):2241-2260
Natural Hazards - Since the initial collision at 55 Ma, rocks of the Indian crust below the Himalayas have undergone modification chemically and compositionally due to the ongoing... 相似文献
6.
Rocket-borne observations of the extinction of solar hydrogen Lyman-alpha radiation made during the solar eclipses of 20 May 1966 at Karistos for normal and 44% visibility and of 7 March 1970 at East Quoddy for normal, 10% and 0.6% visibility have been used to study the variation of temperature in the mesosphere during these events. It is seen that near the mesopause the decrease of temperature at Karistos is by 20° K for 44% visibility and at East Quoddy by 100° K for 0.6% visibility. Possible causes of these temperature variationsvis-a-vis molecular oxygen and pressure variations have been briefly discussed. 相似文献
7.
R. K. Ray T. H. Syed Dipankar Saha B. C. Sarkar A. K. Patre 《Hydrogeology Journal》2017,25(8):2513-2525
Extracted groundwater, 90% of which is used for irrigated agriculture, is central to the socio-economic development of India. A lack of regulation or implementation of regulations, alongside unrecorded extraction, often leads to over exploitation of large-scale common-pool resources like groundwater. Inevitably, management of groundwater extraction (draft) for irrigation is critical for sustainability of aquifers and the society at large. However, existing assessments of groundwater draft, which are mostly available at large spatial scales, are inadequate for managing groundwater resources that are primarily exploited by stakeholders at much finer scales. This study presents an estimate, projection and analysis of fine-scale groundwater draft in the Seonath-Kharun interfluve of central India. Using field surveys of instantaneous discharge from irrigation wells and boreholes, annual groundwater draft for irrigation in this area is estimated to be 212 × 106 m3, most of which (89%) is withdrawn during non-monsoon season. However, the density of wells/boreholes, and consequent extraction of groundwater, is controlled by the existing hydrogeological conditions. Based on trends in the number of abstraction structures (1982–2011), groundwater draft for the year 2020 is projected to be approximately 307 × 106 m3; hence, groundwater draft for irrigation in the study area is predicted to increase by ~44% within a span of 8 years. Central to the work presented here is the approach for estimation and prediction of groundwater draft at finer scales, which can be extended to critical groundwater zones of the country. 相似文献
8.
9.
Pramoda Kumar Samal Rajib Saha Pankaj Jain John P. Ralston 《Monthly notices of the Royal Astronomical Society》2008,385(4):1718-1728
We introduce new symmetry-based methods to test for isotropy in cosmic microwave background (CMB) radiation. Each angular multipole is factored into unique products of power eigenvectors, related multipoles and singular values that provide two new rotationally invariant measures mode by mode. The power entropy and directional entropy are new tests of randomness that are independent of the usual CMB power. Simulated Galactic plane contamination is readily identified. The ILC– WMAP data maps show seven axes well aligned with one another and the direction Virgo. Parameter free statistics find 12 independent cases of extraordinary axial alignment, low power entropy, or both having 5 per cent probability or lower in an isotropic distribution. Isotropy of the ILC maps is ruled out to confidence levels of better than 99.9 per cent, whether or not coincidences with other puzzles coming from the Virgo axis are included. Our work shows that anisotropy is not confined to the low l region, but extends over a much larger l range. 相似文献
10.
M. L. Dotaniya S. Rajendiran M. Vassanda Coumar V. D. Meena J. K. Saha S. Kundu A. Kumar A. K. Patra 《International Journal of Environmental Science and Technology》2018,15(2):441-448
A pot culture experiment was conducted to study impact and interaction of multi-metals on growth, yield and metals uptake by spinach (variety All Green). Three levels of each chromium (0, 50 and 100 mg/kg), cadmium (0, 1 and 2 mg/kg) and zinc (0, 10 and 20 mg/kg) in combinations (total treatments 3 × 3 × 3 = 27) were applied in a Vertisol (5 kg). The results showed that increasing the concentration of chromium, cadmium and zinc in soil enhanced the respective metal concentrations in spinach root and shoot. When cadmium at 2 mg/kg along with chromium at 100 mg/kg soil was applied, chromium concentration and uptake were decreased in root and shoot. Meanwhile, zinc application had no significant effect on chromium uptake and concentration in spinach biomass. From the results, it was concluded that cadmium at higher dose had an antagonistic effect over chromium. On the other hand, in chromium, cadmium and zinc combinations particularly at their higher levels, a competition among each other was found. Therefore, the findings could be used as guidelines for controlling and management of heavy metals pollution in farmland. 相似文献