Background & Aims of the Study: Natural organic matters (NOMs) are a mixture of chemically complex polyelectrolytes produced mainly from the decomposition of plant and animal residues that are present in all surface and groundwater resources. This paper evaluates the aqueous NOMs adsorption efficiency on walnut shell modified with Zinc Oxide (ZnO). Materials & Methods: This stud...

background: the method of proton induced x-ray emission (pixe) has been widely used as a sensitive technique to trace elemental analysis in both biological and medical fields. the sensitivity of this powerful method is in the order of ppm .the aim of this work is to analyze structural composition of 4 heavy trace elements with z greater than 24 (mn, fe, cu, zn) in two kinds of gallstones and to...

background; various industries produce and discharge wastes containing different heavy metals into the environment. apart from using living biomass, dead and dried biomasses have been introduced as a new field of biotreatment technology. method; the cadmium (cd) (ii) removal characteristics of live (growing), dead (autoclaved), and oven-dried biomasses of aspergillus versicolor were examined as...

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Established natural oyster reefs historically provide a three‐dimensionally complex habitat utilized by variety of resident and transient species, but newly created designed to counter the loss initially may lack similar complexity. The loosely stacked shells little resemble vertically interconnected live dead shell matrix typical older reefs. Reduced complexity on alter predator–prey dynamics ...

In some cases the optimum is the minimum of the objective function (mathematical optimum), but in other cases the optimum is given by a technical constraint (technical optimum). The present paper shows the both types in two problems. The first problem is to find the optimum dimensions of a ring-stiffened circular cylindrical shell subject to external pressure, which minimize the structural cost...