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| 1 | Vibration analysis of axisymmetric functionally graded viscothermoelastic spheres显示文摘The present study focuses on the analysis of free vibrations of axisymmetric functionally graded hollow spheres.The material is assumed to be graded in radial direction with a simple power law.Matrix Fro¨benious method of extended power series is employed to derive the analytical solutions for displacement,temperature,and stresses.The dispersion relations for the existence of various types of possible modes of vibrations in the considered hollow sphere are derived in a compact form.In order to explore the characteristics of vibrations,the secular equations are further solved by using fixed point iteration numerical technique with the help of MATLAB software.The numerical results have been presented graphically for polymethyl methecrylate materials in respect of natural frequencies,frequency shift,inverse quality factor,displacement,temperature change,and radial stress. | D.K.Sharma J.N.Sharma S.S.Dhaliwal V.Walia | 2014 | Acta Mechanica Sinica2014,30,1: | 2 |
| 2 | Bio-amelioration of alkali soils through agroforestry systems in central Indo-Gangetic plains of India显示文摘A long-term field study was initiated during 1995 at Central Soil Salinity Research Institute, Regional Research Station, Lucknow(26°47′58′′ N and 80°46′24′′ E) to analyze the effect of agroforestry systems on amelioration of alkali soils. Three agroforestry systems(pastoral, silvipastoral and silvicultural) were compared with the control where no agroforestry system was introduced. Tree-based silvicultural and silvipastoral systems were characterized by tree species Prosopis juliflora and Acacia nilotica along with grass species Leptochloa fusca, Panicum maximum, Trifolium alexandrium and Chloris gayana. Growth of ten-year-old Prosopis juliflora and Acacia nilotica planted in combination with grasses was significantly higher over the silviculture system with the same species. Tree biomass yields of P. juliflora(77.20 t?ha-1) and A. nilotica(63.20 t?ha-1) planted under silvipastoral system were significantly higher than the sole plantation of(64.50 t?ha-1 and 52.75 t?ha-1). Fodder yield under the pastoral system was significantly higher than the silvipastoral system during initial years but it was at par with that of silvipastoral systems after eight years of plantation. The microbial biomass carbon in the soils of silvipastoral systems was significantly higher than in soils under sole plantation of trees and control systems. The Prosopis-based silvipastoral system proved more effective in reducing soil pH, displacing Na+ from the exchange complex, increasing organic carbon and available N, P and K. Improvement in soil physical properties such as bulk density, porosity, soil moisture and infiltration rate was higher in the Prosopis-based silvipastoral system than in the silviculture system or control. On the basis of biomass production and improvement in soil health due to tree + grass systems, silvipastoral agroforestry system could be adopted for sustainable reclamation of highly alkali soils. | Y.P.Singh Gurbachan Singh D.K.Sharma | 2014 | Journal of Forestry Research2014,25,4: | 2 |
| 3 | Fractionation of coal through organo-separative refining for enhancing its potential for the CO2-gasification显示文摘Coal gasification has already been extensively studied earlier under varying conditions of steam,CO2,O2,inert conditions.Belbaid coal and its e,N and NMP-DETA SCC products recovered through organo-refining under milder ambient pressure conditions were subjected to CO2-gasification in a fixed bed reactor under varying conditions.CO2 being an inert gas becomes the most challenging to be utilized during the gasification process.The SCCs showed better CO2-gasification reactivity than the raw Belbaid coal at 900°C.The use of the catalyst K2CO3 tremendously increased the gasification reactivity for both raw coal and the SCCs.The use of sugarcane bagasse for CO2-gasification along with raw coal as well as with residual coal was also studied.Gasification under CO2 atmosphere conditions was used to structurally understand the coals as the coal structure gets loosened after extraction. | Heena Dhawan Rohit Kumar Sreedevi Upadhyayula K.K.Pant D.K.Sharma | 2020 | International Journal of Coal Science & Technology2020,7,3: | 1 |
| 4 | Design of experiments to optimize the extraction parameters of a power grade Indian coal显示文摘Low grade high ash coals with difficult physical washability characteristics require chemical cleaning techniques such as solvent extractio n to obtain super clean coal with lower ash conte nts.Kedla,an In di an low grade coal has ash con tent around 44%-50%and there is a need to maximize its solvent extraction yield so as to make this power grade coal industrially useful.This paper highlights the use of definitive screening design and response surface methodology to extract the maximum organic matter from Kedla coal using ethylenediannnine(EDA)and N-methyl pyrollidone(NMP)as solvents under mild atmospheric pressure conditions.The coal was pre-treated with acetic acid before extractions were carried out.The parameters such as the acid pre-treatment time,acid concenmion,particle size,the co-solvent concentratio n and the solvent concentration were optimized in this paper.With this design of experimenls technique about 40%of the organic matter with minimal ash(less than 2%)content was「endered extractable unlike the already postulated designer solvent system—e,N system(i.e.NMP containing small amount of EDA)that uses coal to solve nt ratio as 1:17(wt/vol)and coal to co-solvent ratio as 1:l(wt/vol)thus only giving 19%extraction yield.Therefore,the present design of experimetechnique helps in conserving the number of experimems for process intensification. | Heena Dhawan Sreedevi Upadhyayula D.K.Sharma | 2018 | International Journal of Coal Science & Technology2018,5,4: | 1 |
| 5 | 芒果育种 | D.K.Sharma 高勇 | 1989 | 世界热带农业信息1989,,5: | 0 |
| 6 | 印度恒河平原苏打土壤种植的10个多功能树种生物量和生物能产量(英文)显示文摘评价了10个多功能树种--阿江榄江树(Terminalia arjuna)、印楝(Azadirechta indica)、牧豆树(Prosopis juliflora)、水黄皮(Pongarnia pin-nata)、木麻黄(Casuarina equisetifolia)、角豆树(Prosopis alba )、阿拉伯金合欢(Acacia nilotica)、细叶桉(Eucalyptus tereticornis)、牛蹄豆(Pithecellobium dulce)、铁刀木(Cassia siamea )等10年间的生物量和生物能产量,这些树种采用单种栽培的农作方式种植于印度北部恒河平原苏打土壤。该地区土壤紧密、盐碱化、透水性差、营养匮乏。10个树种中,细叶桉植株最高,牧豆树和木麻黄次之。阿拉伯金合欢林分基面积为3.04m2·hm-2,植株胸径优于其他树种,牧豆树和木麻黄植株胸径次之。10年间,牧豆树和Acacia nilotica分别产出生物量56.50和50.75 Mg·hm-2,而阿拉伯金合欢、水黄皮和角豆树生物量产出量较小。牧豆树的营养需求和净生物量产出均最大,而且叶片中营养元素(N,P,K,Ca和Mg)含量较高。然而,树种间木质成分差异较小。以每吨木材营养元素产出量计算,氮素在阿拉伯金合欢中产出量最低,磷和钾分别在阿江榄仁树和牛蹄豆中产出最低,钙和镁在牧豆树中产出最低。牧豆树生物质能产量最高1267.75 GJ·hm-2,阿拉伯金合欢次之1206 GJ·hm-2,印楝最低(520.66GJ·hm-2)。图2表7参31。 | Y.P.Singh Gurbachan Singh D.K.Sharma | 2010 | Journal of Forestry Research2010,21,1: | 0 |