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151.
S. P. Singh 《Geotechnical and Geological Engineering》1989,7(3):257-266
Conclusions The application of mechanical methods for rapid excavation requires more detailed and precise knowledge of the site, but there is no single parameter which can provide a comprehensive measure for the selection and performance of a tunnel boring machine.The machinability index proposed in this paper is based on four different parameters which influence the performance of a tunnelling machine and are widely accepted by the engineers and geologists. In order to develop a comprehensive measure regarding the borability of rocks,in situ conditions must be evaluated. The machinability index coupled with thein situ information would facilitate judicious decisions regarding the application and selection of tunnel boring machines.The geological conditions and rock characteristics cannot be controlled but their knowledge can prevent costly mistakes in equipment selection and assist in identifying alternative excavation systems, therefore a thorough site investigation can substantially reduce the economic and technical risks associated with tunnelling and mine development. 相似文献
152.
153.
Surendra Singh K. D. Sharma Nepal Singh D. N. Bohra 《Journal of the Indian Society of Remote Sensing》1988,16(4):53-56
Temporal changes in ephemeral river courses and associated flood plains, which could not be detected by Landsat MSS due to its poor spatial resolution of 80m, have been identified and mapped within 10% accuracy by Landsat TM False colour composite because of its higher spectral and spatial resolution of 30 m. Over a period of 28 years (1958–86) the river courses widened upto 1.8 times through bank erosion due to the recurring flash floods. The flash floods have also caused morphological, soil fertility and landuse changes in the associated flood plains, which could also be monitored by the Landsat TM. 相似文献
154.
Summary The relationship of the point load test with uniaxial compressive strength was examined using quartzite rocks to substantiate the existing correlations. 相似文献
155.
EvaluationofForecastPerformanceofanEconomicalExplicitTimeIntegrationSchemeinaLimitedAreaModeloverIndianRegionA.Bandyopadhyaya... 相似文献
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158.
Exposure of Channa striatus over 24 h to 40% and 80% of the LC50;24h of the three pyrethroids cypermethrin, permethrin, and fenvalerate did not cause any significant changes in the levels of total protein and free amino acids in the liver and muscle tissues of the fish. After 96 h exposure, the protein amino acid levels are altered significantly. 相似文献
159.
Carlsberg Ridge, northern Indian Ocean: gravity and isostasy 总被引:1,自引:0,他引:1
160.
Influence of multipurpose trees on agricultural crops in arid regions of Haryana, India 总被引:2,自引:0,他引:2
The effects of multipurpose trees on the productivity of agricultural crops were studied in the arid regions of Haryana. In one of the experiments, wheat was grown on irrigated farms having scattered trees ofDalbergia sissoo, Azadirachta indica, Prosopis cinerariaandAcacia nilotica. Data of wheat yield for each tree species at different distances (1, 3, 5, and 7 m) and four directions (East, West, North and South) from the tree bases and control (no trees) were collected. Results indicate thatAzadirachta indicaandProsopis cinerariadid not produce any significant difference in the wheat yield while the other two species (Dalbergia sissooandAcacia nilotica) gave a reduction in yield.A. niloticahad a more significant and prominent effect and a reduction of 40 to 60 % wheat yield was observed.Dalbergia sissooreduced yield by 4 to 30 % but the reduction was only up to a distance of 3 m. In general, the impact of trees on productivity was observed up to 3 m distance and there was little, if any, impact up to 5 m and almost no impact at 7 m.In another experiment,D. sissoo(18-years-old) was raised as windbreak and productivity of cotton was assessed. The tree belt reduced the wind speed by 15 to 45 %, depending on season and wind speed. The influence of trees on cotton yield was observed to be negative up to 2H (36 m), where H is tree height, i.e. 18 m. Cotton productivity was observed to be maximum between 2H and 5H. Depending upon orientation of tree belt, the increase in cotton yield was found to be 4 to 10 %. 相似文献