نتایج جستجو برای: water pollution and ecological changes regarding these mentioned problems
تعداد نتایج: 17126011 فیلتر نتایج به سال:
there are many approaches for solving variety combinatorial optimization problems (np-compelete) that devided to exact solutions and approximate solutions. exact methods can only be used for very small size instances due to their expontional search space. for real-world problems, we have to employ approximate methods such as evolutionary algorithms (eas) that find a near-optimal solution in a r...
Sediments are one of the biological indicators of the accumulation of heavy metals in aquatic ecosystems, which, due to the stability of a region, can well measure pollution. This research was conducted in 2018 with the aim of investigating heavy metals of Cobalt, Chromium, Manganese, Selenium and Molybdenum in sediments of Hooralazim wetland in Khuzestan province. A total of 27 sediment sample...
considering the lack of sufficient fresh water resources for aquaculture and at the same time the pollution of fresh water through the process of fish farming, a project was carried out within 15 days to survey the effects of water flow increment on rainbow trout culture by reusing the outlet effluent under a complete random design with 4 treatments and 3 replicate. the water quality factors in...
Background and Objective: Considering the toxicity, health and ecological hazards of heavy metals in the environment and the impact on organisms, it looks essential to measure and evaluate their concentrations at the various levels in indigineous ecological strctures. The present study evaluated the concentration of Lead, Nickel, Copper and Zinc and their ecological risk assessment in surface s...
Ecological consequences of large dams, particularly regarding the Three Gorges Dam (TGD) on the Yangtze River in China, have been controversially and internationally discussed. Water quality within the Three Gorges Reservoir (TGR) has been deteriorated by highly underestimated eutrophication and algal blooms. Globally, the TGR is delineated from other comparable reservoirs by its low mean water...
one of the most commonly used techniques to reduce the corrosion rate of rebar in concrete is addition substances named corrosion inhibitors into the concrete. corrosion inhibitor is chemical compounds that were added to concrete to prevent corrosion of steel in concrete. sodium nitrate is a type of anodic inhibitors that this study investigatesthe effect of this inhibitor on the properties of ...
water is an essential yet constrained commodity for human communities and ecological systems depend on it. with population growth and economic development, water resource is increasingly declining. over the past two decades, because of changes in population and climate, and relative welfare increase, the per capita consumption of water has increased. thus, optimal use of available water resourc...
The environmental impact of wind power plants over their life cycle is divided into three stages: construction period, operation period and retired period. The impact is mainly reflected in ecological destruction, noise pollution, water pollution and the effect on bird migration. In response to these environmental effects, suggesting reasonable locations, reducing plant footprint, optimizing co...
Environmental law plays a key role in shaping policy for sustainability. In particular, the types of legal instruments, institutions, and the response of law to the inherent variability in socio-ecological systems are critical.1 Environmental protection has typically involved a command-and-control approach that is implemented in response to specific environmental problems.2 Often the response i...
in this study reference as one of the five cohesive devices in the achievement of textuality in english and persian narrative/descripitive written texts is focused on and analysed . to do so , the theoretical framework elaborated by halliday and hasan (1976) and its version adapted by the writer to match the sub-types of reference in farsi are applied to the analysis of reference in english and...
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