نتایج جستجو برای: clean and highly polluting
تعداد نتایج: 16861977 فیلتر نتایج به سال:
in this paper, we introduce the new notion of n-f-clean rings as a generalization of f-clean rings. next, we investigate some properties of such rings. we prove that mn(r) is n-f-clean for any n-f-clean ring r. we also, get a condition under which the denitions of n-cleanness and n-f-cleanness are equivalent.
One of the major current challenges before chemists is to develop synthetic methods that are less polluting, i.e., to design clean or ‘green’ chemical transformations. The chemical manufacturing processes should be such that they do not cause permanent damage to the environment or disturb the ecological balance. Ways to minimize the consumption of energy and raw materials used in synthesis must...
Cadmium is a highly polluting heavy metal known to have undesirable effects on health in both animals and humans, targeting the kidneys, the liver and the vascular system. A wide spectrum of deleterious effects has been reported also on the reproductive organs and the developing embryo. Cadmium in fact is a strong endocrine disruptor that interferes with functioning of endogenous receptors and ...
The Environmental Kuznets Curve (EKC) hypothesis postulates an inverted-U-shaped relationship between different pollutants and per capita income, i.e., environmental pressure increases up to a certain level as income goes up; after that, it decreases. An EKC actually reveals how a technically specified measurement of environmental quality changes as the fortunes of a country change. A sizeable ...
The effect of economic growth on environmental quality is much under dispute. A number of empirical studies have made the claim that there exist in some income ranges a positive relation between per capita income and some measure of environmental quality. According to this inverted U-shaped pattern of different pollutants relative to per capita incomes in different countries which is also calle...
Climate change is a global problem with grave implications: environmental, social, economic, political and for the distribution of goods. It represents one of the principal challenges facing humanity in our day. . . . There is an urgent need to develop policies so that, in the next few years, the emission of carbon dioxide and other highly polluting gases can be drastically reduced, for example...
The estimated global ethanol production in 2009 was about 74 mln m. After fermentation remains waste from bottom of distillation columns, termed stillage. This highly aqueous residue containing organic solubles is considered a troublesome and potentially polluting waste due to its extremely high BOD and COD values. Moreover, for each liter of produced ethanol 8 -15 liters of stillage are genera...
This procedure has developed the use of TiO2 nanoparticles as an environmentally friendly and highly efficient heterogenous nanocatalyst for the eco-safe, facile and one-pot three-component Biginelli synthesis of biologically active corresponding 3,4-dihydropyrimidin-2-(1H)-one/thione derivatives under solvent-free conditions. This eco-friendly protocol provi...
A simple, highly efficient and green procedure for the condensation of o-phenylenediamines with 1, 2-dicarbonyl compounds in the presence of vitamin C, as an inexpensive organocatalyst, is described. Using this method, variety of quinoxaline derivatives with different electron releasing and electron withdrawing substituents, are produced in high to excellent yields at room temperature in ethano...
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