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71.
Review: Computer-based models for managing the water-resource problems of irrigated agriculture 总被引:1,自引:0,他引:1
Ajay Singh 《Hydrogeology Journal》2015,23(6):1217-1227
72.
Ajay Kumar Sreerama Rajaram Chenna Mishra Shashank Pradeep Kumar Ramancharla Karnath Anoop 《Natural Hazards》2017,85(3):1851-1875
Natural Hazards - Methods capable of assessing the vulnerability of houses for future earthquakes are of fundamental importance for the safety and development of an area. As the detailed assessment... 相似文献
73.
Ajay Manglik 《Journal of Earth System Science》2005,114(2):169-176
During the solidification of a lava lake heat is released convectively from the top surface as well as conductively into the
country rock from the base, leading to non-uniform solidification. The upper solidified layer grows at a faster rate than
the lower solidified layer. Similarly, solidification of magma intrusion within the crust is also non-uniform due to the presence
of thermal gradient in the crust. Available analytical solution for solidification of a melt layer assumes only symmetric
cooling about the centre of the layer. In the present work a moving boundary solution for thermal evolution and non-uniform
solidification of a melt layer incorporating time-varying contact temperature conditions at both of its boundaries is developed.
The solution is obtained by using the Fourier spectral approach in the space domain and a modified finite difference scheme
in the time domain, and is validated with available analytical solutions for simple cases and a semi-analytical solution for
the case involving temperature gradient in the country rock. This solution can be used to analyse solidification of lava lakes
and magma intrusions experiencing time-dependent temperature variation at their contacts with the country rock. 相似文献
74.
Optimal allocation of water and land resources for maximizing the farm income and minimizing the irrigation-induced environmental problems 总被引:1,自引:1,他引:0
Ajay?SinghEmail authorView authors OrcID profile 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(5):1147-1154
The continuous decrease in good quality water and land resources and concurrent increase in global population accentuates the need of optimal allocation of these resources to fulfilling the rising food requirements. This study presents the formulation and application a management model for the optimal allocation of available good quality water and land resources to maximize the farm revenue of a canal command area. A groundwater balance constraint was imposed on the model, which moderates the irrigation-induced environmental problems of waterlogging and salinization, while making the optimal allocation of resources. The model results show a reduction in mustard, rice, and gram crop areas against an increase in sorghum, millets, and wheat areas. The net annual revenue from the command area increased by about 18 % under the optimal allocation plans. The farmers and stakeholders concerned in the actual agricultural production process are suggested to use groundwater and canal water conjunctively to maximizing the farm income. This strategy would also mitigate the hydrological imbalances to the groundwater system without installing costly drainage systems which is not viable as the quality of groundwater is poor and drainage water may cause a serious disposal problem. The developed model can be used as a reliable decision tool for taking the farm and regional level decisions of optimal land and water resources allocation and is able to solve the irrigation-induced environmental problems of agricultural systems. 相似文献
75.
This study evaluates changes in streamflow, temperature and precipitation over a time span of 105 years (1906–2010) in the Colorado River Basin (CRB). Monthly precipitation and temperature data for 29 climate divisions, and streamflow data for 29 naturalized gauges were analyzed. Two variations of the Mann-Kendall test, considering lag-1 auto correlation and long-term persistence, and the Pettitt test were employed to assess trends and shifts, respectively. Results indicated that streamflow increased during the winter–spring months and decreased during the summer– autumn period. Decreasing trends in winter precipitation were identified over snow-dominated regions in the upper basin. Significant increases in temperature were detected over several months. Major shifts were noticed in 1964, 1968 and in the late 1920s. Increasing temperature while decreasing streamflow and precipitation were noticed after major shifts in the 1930s, and these shifts coincided with coupled phases of El Niño Southern Oscillation and Pacific Decadal Oscillation.
EDITOR A. Castellarin; ASSOCIATE EDITOR R. Hirsch 相似文献
76.
Zoë E. Glas Jackie M. Getson Yuling Gao Ajay S. Singh Francis R. Eanes Laura A. Esman 《社会与自然资源》2019,32(2):229-237
Response rates to mail-based surveys have declined in recent decades, and survey response rates for farmers tend to be low overall. Maintaining high response rates is necessary to prevent non-response bias. Historically, incentives have been an effective tool to increase response rates with general populations. However, the effect of incentives on farmers has not been well tested. In this study, we experimentally manipulated the use of a $2 incentive in two surveys targeted at farmers. We tested both the use of the incentive and the timing of incentive distribution in the survey process. We found the incentive significantly increased response rates with farmers but there was no significant effect of when the incentive was distributed. Additionally, we evaluated the cost-effectiveness of using the incentive. While the incentive increased response rate, the cost per survey response also increased and the cost of the incentive was not offset by the increased response rate. 相似文献