Hydromagnetic thin film flow of Casson fluid in non-Darcy porous medium with Joule dissipation and Navier＇s partial slip

In this paper, the effects of viscous and Ohmic heating and heat genera- tion/absorption on magnetohydrodynamic flow of an electrically conducting Casson thin film fluid over an unsteady horizontal stretching sheet in a non-Darcy porous medium are investigated. The fluid is assumed to slip along the boundary of the sheet. Similar- ity transformation is used to translate the governing partial differential equations into ordinary differential equations. A shooting technique in conjunction with the 4th order Runge-Kutta method is used to solve the transformed equations. Computations are car- ried out for velocity and temperature of the fluid thin film along with local skin friction coefficient and local Nusselt number for a range of values of pertinent flow parameters. It is observed that the Casson parameter has the ability to enhance free surface velocity and film thickness, whereas the Forchheimer parameter, which, is responsible for the inertial drag has an adverse effect on the fluid velocity inside the film. The velocity slip along the boundary tends to decrease the fluid velocity. This investigation has various applications in engineering and in practical problems such as very large scale integration （VLSI） of electronic chips and film coating.

Assessment of ecosystem services of rice farms in eastern India

Background:Rice is a major cereal crop and staple food of eastern India,and most farmers depend solely on rice for their livelihood.Rice farming provides both tangible and non-tangible benefits to ecosystems which need to be maintained and enhanced.These benefits are provided through ecosystem services(ES)that include both marketable and non-marketable.Methods:In this study,the rice farms in eastern India were valued by quantifying the economic value of the services under conventional method of rice cultivation and the gap of ecosystem services value and farm income per unit area were assessed.A stratified random sampling technique was used in this study for selection of agro-climatic zones,districts,blocks,gram panchayat,and study units(households).Soil sampling was also performed for assessing the regulating services(biocontrol of pests,carbon flow,soil erosion,nitrogen fixation),provisioning services(food and by-products),and supporting services(soil fertility,hydrological flow,nutrient cycling,and soil formation).Results:The results indicated that the total economic value of ecosystem services ranged from US$1238 to 1688 ha−1 year−1.The marketed(primary production)and non-marketed ecosystem services values ranged from 66–89 to 11–34%of the total,respectively.Valuation of some of the ecosystem services such as cultural services,biodiversity,and gas regulation,which may play a significant role in total ecosystem services,has not been made due to non-availability of data and appropriate methodology for rice ecosystem.Different values of parameters can explain the variability in ecosystem services among the agro-climatic zones in eastern India.Clustering of locations based on variability of ecosystem services helps in identifying intervention points for sustaining and improving ecosystem services,while permitting sustainable agro-ecological intensification.The highest total economic gap between ES value and farm income was found in the north central plateau zone(US$1063 ha−1 year−1)and the lowest in the north western plateau zone(US$670 ha−1 year−1).Conclusion:We suggest various measures to reduce the economic gap,including payments for ecosystem services for rice farming for sustainability of the ecosystem and agricultural development,while ensuring reliable farm income.