نتایج جستجو برای: ecological systems indefinite weight grazing and constant yield harvesting sub supersolution method
تعداد نتایج: 17299149 فیلتر نتایج به سال:
this research is a study on indicators of listening instruction in iranian english as a foreign language (efl) curriculum at guidance school and high school educational levels. this thesis aims at determining: a) the indicators of listening instruction at guidance school and high school efl curriculum. b) the indicators of listening instruction in irans guidance school and high school efl curri...
today, scouring is one of the important topics in the river and coastal engineering so that the most destruction in the bridges is occurred due to this phenomenon. whereas the bridges are assumed as the most important connecting structures in the communications roads in the country and their importance is doubled while floodwater, thus exact design and maintenance thereof is very crucial. f...
this research was conducted under greenhouse conditions to evaluate the optimum combination of irrigation and fertilizer levels to attain the best yield and quality of tomato crop. the experiment was conducted by using a split-plot design with three replicates. irrigation levels were applied to the main plots and fertilizer levels to the sub-plots. for each experimental unit, the irrigation lev...
Beyond grazing, managed grasslands provide ecological services that may offer economic incentives for multifunctional use. Increasing biodiversity of plant communities may maximize net primary production by optimizing utilization of available light, water, and nutrient resources; enhance production stability in response to climatic stress; reduce invasion of exotic species; increase soil OM; re...
in the first part of this thesis we explored wetting and its dynamics for small droplets. first, we showed how a simple feature of water droplets on a surface, i.e. laplace pressure, can be exploited to build a micropump. we investigated capillary pumping in microchannels both experimentally and numerically. putting two droplets of different sizes at the in/outlet of a microchannel, will ge...
With regard to retrogression trend of rangelands in central Zagross, many native plant species are expected to be increasingly on the verge of extinction. Therefore, for proper rangeland management the optimum harvest intensity of important plant species is an essential factor for rehabilitation and recovery of native rangeland species. This research was aimed to study the response of four rang...
We consider a second-order nonlinear degenerate anisotropic parabolic equation in the case when flux vector is only continuous and nonnegative diffusion matrix bounded measurable. The concepts of entropy sub- supersolution Cauchy problem are introduced, so that solution this problem, understood sense Chen-Perthame, both an supersolution. It established maximum subsolutions also subsolution prob...
Multipurpose use of rangelands is one of the new challenges facing rangeland users, according to which grazing pressure in rangelands can be reduced and an important step can be taken to increase the welfare and empowerment of rangelands, preserve ecosystems and improve ecosystem services related to them. Therefore, the present study was conducted to evaluate the capability of mountain rangelan...
Production of halophytes using saline waters and soils, and feeding livestock with them, is one of the most sustainable ways of desert ecosystems conservation and food production for people living in these areas. A field experiment was conducted at Salinity Research Station, Ferdowsi University of Mashhad, in 2007 to evaluate the effect of planting density and harvesting time on oil and protein...
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