closed-loop supply chain network design is a critical issue due to its impact on both economic and environmental performances of the supply chain. in this paper, we address the problem of designing a multi-echelon, multi-product and capacitated closed-loop supply chain network. first, a mixed-integer linear programming formulation is developed to maximize the total profit. the main contribution...

introduction:different types of prosthesis are available for stapes replacement. because there has been no published report on the efficacy of the titanium soft-clip vs the fluoroplastic causse loop teflon piston, we compared short-term hearing results of both types of prosthesis in patients who underwent stapedotomy due to otosclerosis.materials and methods:a total of 57 ears were included in ...

the aim of this paper is to minimize output phase noise for the pure signal synthesis in the frequency synthesizers. for this purpose, first, an exact mathematical model of phase locked loop (pll) based frequency synthesizer is described and analyzed. then, an exact closed-form formula in terms of synthesizer bandwidth and total output phase noise is extracted. based on this formula, the phase ...

since treatment of landfill leachate is quite complicated, there is a need to develop a system thatis capable of providing high treatment efficiencies. in this study, the treatment performance of a jet - loopmembrane bioreactor (jlmb) operated at different organic loading rates was investigated by observing thechanges in chemical oxygen demand (cod), total kjehldahl nitrogen (tkn) and total amm...

excessive cutting depth during leveling of agricultural land increases power needed by the tractor drawbar and will result in undesirable slippage and excessive strain on the tractor engine.  the result of sustained excess will be the break-down of the tractor. an auxiliary blade depth controller to prevent overloading during leveling was designed, fabricated and evaluated in this study. the sy...

conclusions the analytical sensitivity of lamp and pcr methods, using the designed primers, was 8 times more than any other reported methods. the designed methods are specific and sensitive for detection of h. pylori in different clinical and environmental samples. results the detection limits of the lamp and pcr assay were similar and were 10 fg of pure dna of h. pylori, which is equal to 6 co...

the steps taken in designing a loop reactor for bulk propylene polymerization are discussed. the roles played by several parameters like particle growth factor, catalyst activity and solid fraction on reactor volume at different operating conditions are investigated. at first, based on a fixed production capacity and specific rate of catalyst, reactor volume is determined. next, the length and ...