slow sand filters are as a proper technology for pre-treatment of raw water, with a fine and medium trubidity in small communities in developing countries. thus, with a minimum operation cost and minimum need for expest bodies have the maximum efficiency. the purpose of this research is carried out to evaluate the efficiency of two processes of horizontal flow roughing filter and vertical flow ...

Abstract In this paper, a new upper bound for the Multiple Knapsack Problem (MKP) is proposed, based on idea of relaxing MKP to Bounded Sequential Problem, i.e., multiple knapsack problem in which item sizes are divisible. Such relaxation, called sequential obtained by suitably replacing items instance with divisible sizes. Experimental results benchmark instances show that effective, terms qua...

Divisible E-cash has been introduced twenty years ago but no construction is both fully secure in the standard model and efficiently scalable. In this paper, we fill this gap by providing an anonymous divisible E-cash construction with constant-time withdrawal and spending protocols. Moreover, the deposit protocol is constant-time for the merchant, whatever the spent value is. It just has to co...