توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Experimental investigation and modelling of two phase flow in horizontal 90◦ and 180◦ bends
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کنفرانس لوله و صنایع وابسته، سال
تعداد صفحات: ۱۶
In this research the influences of horizontal 90◦ and 180◦ bends on the two phase pressure loss and flow pattern for air–water mixtures inside a 2.4 cm smooth pipe are investigated. Based on experimental pressure loss data in bends a prediction model is proposed. Comparison of new model with previous models in the literature shows that this model provides a better estimate of pressure loss in bends. Several experiments are also accomplished to observe flow pattern in presence of bends. In region of flow, the flow pattern in the recovery region is temporarily turned into annular flow. Based on the present visualization, two flow pattern maps are proposed to describe the effect of bends on transition of flow pattern.<\div>

۲Flux Distribution in Bacillus subtilis: Inspection on Plurality of Optimal Solutions
نویسنده(ها): ،
اطلاعات انتشار: Iranian Journal of Biotechnology، نهم،شماره۴(پياپي ۳۶)، ۲۰۱۱، سال
تعداد صفحات: ۷
Linear programming problems with multiple optimal solutions are challenging due to the choice of multiple strategies resulting in the same optimal value of the objective function. However, searching for these solutions is a tedious task especially when using mixed integer linear programming (MILP), as previously applied to metabolic models. Therefore, judgment on plurality of optimal metabolic flux distributions (solutions) a priori to applying MILP approach could prevent unnecessary computations. In this work for the first time, the reduced cost coefficients for the non–basic variables in a current solution of a metabolic model were utilized to inspect the possibility of multiple optimal flux distributions. If there exists at least one non–basic variable with zero reduced cost coefficient, multiplicity of optimal solution may occur where MILP can be used to find these optimal solutions. This approach was implemented on a metabolic network of Bacillus subtilis aiming to reduce the cell energy requirement. Solving the model at fixed specific growth rate of 0.4 h–1 resulted in minimum energy requirement of 12.67 mmol (g h)–1. Inspection of reduced cost coefficients showed that six non–basic variables had zero reduced cost coefficients at current optimal solution, which proves that there can exist multiple optimal solutions. Subsequently by applying MILP, five optimal flux distributions at minimized energy requirement were identified, among which one showing no acid production and minimum glucose consumption rate was selected as the superior solution.
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