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排序方式: 共有196条查询结果,搜索用时 15 毫秒
21.
Christopher P. Burgess Michael A. Taylor Tannecia Stephenson Arpita Mandal Leiska Powell 《Natural Hazards》2015,78(1):231-256
Floods account for more than half of the global hydrometeorological risks. Severe floods cause significant economic shocks and loss of lives, particularly for developing countries such as Jamaica. There is need for more information on the present and projected flood risks to justify macro-scale planning for climate change adaptation and facilitate the decision-making processes. In this study, a catalogue of 198 flood events occurring between 1678 and 2010 is compiled for Jamaica and used to examine the climatology, occurrence, trends, causes and duration of the island’s severe events. The annual flood risk is estimated to be a loss of life rate of 4 persons and estimated annual damage of USD96.3 million per annum in 2010 values and approximately 0.84 % of GDP per annum. Macro-scale models for flood risks (deaths and damages) are also developed using data from the flood catalogue and maximum precipitation at the town and parish level. The models examine the relationship between flood risks (death and damages) and extreme rainfall depths and intensities. Future climate risks of loss of lives and damages are predicted to increase 11 and 9 %, respectively, to 4.4 persons and USD105.2 million per annum. 相似文献
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A. Datta T. Saud A. Goel S. Tiwari S. K. Sharma M. Saxena T. K. Mandal 《Journal of Atmospheric Chemistry》2010,65(2-3):127-143
The temporal variation of ambient SO2 and the chemical composition of particulate matters (PM2.5 and PM10) were studied at National Physical Laboratory (NPL), New Delhi (28°38′N, 77°10′E). Spatial variation of SO2 at seven air quality monitoring stations over Delhi was also studied simultaneously. Wide range of ambient SO2 was recorded during winter (2.55 to 17.43 ppb) compare to other seasons. SO2 mixing ratio was recorded significantly high at industrial sites during winter and summer; however, no significant spatial difference in SO2 mixing ratio was recorded during monsoon. SO 4 2? /(SO2+SO 4 2? ) ratio was recorded high (0.74) during winter and low (0.69) during summer. Monthly variation of PSCF was analyzed using HYSPLIT seven days backward trajectories and daily average SO2 data. PSCF analysis suggests that, during winter (December, January, February) ambient SO2 at the study site might have contributed from long distance sources, located towards west and southwest directions; during monsoon (July, August, September) marine contribution was noticed; whereas, during summer (April, May and June) it was from regional sources (located within few 100 km of study site). During winter there was significant contribution from the long distance sources located in western Asia, northwestern Pakistan, Rajasthan and Punjab provinces of India. Coal used in thermal power plants at Panipat (in the northwestern side) and Faridabad (in the southeastern side), local industries, soil erosion and biomass burning may be major contributing factors for SO2 during summer. The study establishes that the transport sector may not be the major source of ambient SO2 in Delhi. 相似文献
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Dispersion of Rayleigh type surface wave propagation has been discussed in four-layered oceanic crust. It includes a sandy layer over a crystalline elastic half-space and over it there are two more layers—on the top inhomogeneous liquid layer and under it a liquid-saturated porous layer. Frequency equation is obtained in the form of determinant. The effects of the width of different layers as well as the inhomogeneity of liquid layer, sandiness of sandy layer on surface waves are depicted and shown graphically by considering all possible case of the particular model. Some special cases have been deduced, few special cases give the dispersion equation of Scholte wave and Stoneley wave, some of which have already been discussed elsewhere. 相似文献
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For a class of boundary value problems associated with flexural gravity waves, characteristics of the eigen-system are analysed which are used to study the convergence of the expansion formulae in both cases of single and two layer fluids in water of finite and infinite depths. Using Green’s function technique, the spectral representations of the vertical eigenfunctions are obtained which are used along with the orthogonal mode-coupling relations to prove the convergence of the expansion formulae. Using the expansion formulae flexural gravity wave scattering due to multiple articulations in the presence of compression are investigated. The problem is studied in both the cases of single-layer and two-layer fluids in finite water depth. Effects of compressive force, stiffness of the connectors, length of the elastic plates and water depth, position of interface on wave scattering by articulated plates are studied by analysing the reflection and transmission coefficients. This procedure of proving the convergence of expansion formulae is independent of water depth. The concept and methodology for dealing with wave-structure interaction problems discussed here can be generalised to deal with problems of similar nature arising in the broad area of mathematical physics and engineering. 相似文献
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Ipsita Mandal Arnab K. Ray Tapas K. Das 《Monthly notices of the Royal Astronomical Society》2007,378(4):1400-1406
The stationary, spherically symmetric, polytropic and inviscid accretion flow in the Schwarzschild metric has been set-up as an autonomous first-order dynamical system, and it has been studied completely analytically. Of the three possible critical points in the flow, the one that is physically realistic behaves like the saddle point of the standard Bondi accretion problem. One of the two remaining critical points exhibits the strange mathematical behaviour of being either a saddle point or a centre-type point, depending on the values of the flow parameters. The third critical point is always unphysical and behaves like a centre-type point. The treatment has been extended to pseudo-Schwarzschild flows for comparison with the general relativistic analysis. 相似文献
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R. Priyadarshinee A. Kumar T. Mandal D. Dasguptamandal 《International Journal of Environmental Science and Technology》2017,14(8):1713-1728
Kraft lignin (KL) is the chief contaminant which is responsible for dark coloration, toxicity and high chemical oxygen demand (COD) of paper pulp mill effluent. The present study investigated the diverse potentials of Planococcus sp. TRC1 in the biodegradation of KL. Preliminary evaluation indicated that the strain was able to grow on broad spectrum of lignin-derived compounds, decolorize lignin-mimicking dyes and catabolize substrates of ligninolytic enzymes. Response surface methodology (RSM) was executed to perform the optimization of different process parameters. The results displayed that Planococcus sp. TRC1 could completely utilize 100 mg L?1 of KL and 78% of 200 mg L?1 of KL as sole source of carbon with concurrent reduction in COD and color. The biokinetic details of KL biodegradation showed that the values of \(\mu^{*}\), µ max, \(q^{*}\) and q max were 0.018 h?1, 0.01 h?1, 0.023 g g?1 h?1 and 0.05 g g?1 h?1, respectively. UV–visible spectrophotometry, SEM and FTIR indicated the significant alterations in the surface morphology, functional groups and chromophores during the course of biodegradation. XRD revealed the emergence of peak signifying the formation of low molecular weight intermediates after bacterial treatment. Considering the environmental impact, bacterial-treated KL illustrated less phytotoxicity using Vigna radiata seed bioassay. These results suggested that Planococcus sp. TRC1 could be a promising strain for the degradation of KL in an ecofriendly way. 相似文献
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