The potential usage of virgin Low density polyethelyne (LDPE) reinforced with different concentrations (2%, 5% and 6% by weight) of treated rice straw with different lengths (2 mm, 4 mm and 6 mm) is investigated to produce high value products that have technical and environmental demand. The two treatment methods used for rice straw are alkali and acidic treatments of rice straw. The removal of impurities and waxy substances from fiber surface avoid creation of rougher topography after treatment and improves the quality of fiber, also content of hemi cellulose and lignin decrease so increase effectiveness of fiber due to dispersing of fiber in matrix. The reinforcing material is embedded in the matrix material to enhance tensile and flexural behaviors of the synthesized composite. The result of investigating these two mechanical properties, using statistical analysis & design of experiments, showed an enhancement in the mechaniccal properties of the virgin polymer composite compared to the virgin polymer. The flexural stress of the composite increased three times the virgin flexural stress, while the tensile stress increased eight times the original tensile stress

This paper develops a simulation approach to the solution of closed-loop conveyor systems for which analytical solutions are infeasible or too complicated. In addition, the paper considers cases involving more than one type of input to the conveyor systems. The arrival distribution patterns of recirculated units are also studied. The systems' measures of performance are evaluated. GPSS III/360 is utilized as the simulation language.

In the present study, the design of experiments (DOE) methodology is employed to statistically model and optimize the thermal performance of a forced circulation solar water heating system (FSWHS) with various budget constraints using a small number of simulation trails. The simulation trails are implemented using a model developed in TRNSYS 17 software, and climate conditions of Cairo, Egypt. A sequential approach is used to obtain the optimum system configuration with respect to the budget constraint. The definitive screening design is first utilized to eliminate the insignificant factors and investigate the effect of the quadratic terms. Then, the Box-Behnken design (BBD) is used for developing mathematical models based on multiple regression analysis. Finally, the optimization problem is formulated and solved using the desirability function. The developed mathematical models for the thermal performance responses showed a good agreement with the results obtained in TRNSYS for various budget constraints. This agreement proved the ability of the mathematical models to predict the performance of FSWHS precisely. Furthermore, the optimization methodology can be applied for various types of solar water heating systems, and different renewable energy applications.

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