Abstract. Graphene oxide (GO) sheets were chemically grafted with thermotropic liquid crystalline epoxy (TLCP). Then we fabricated composites using TLCP-g-GO as reinforcing filler. The mechanical properties and thermal properties of composites were systematically investigated. It is found that the thermal and mechanical properties of the composites are enhanced effectively by the addition of fillers. For instance, the composites containing 1.0 wt% of TLCP-g-GO present impact strength of 51.43 kJ/m 2 , the tensile strength of composites increase from 55.43 to 80.85 MPa, the flexural modulus of the composites increase by more than 48%. Furthermore, the incorporation of fillers is effective to improve the glass transition temperature and thermal stability of the composites. Therefore, the presence of the TLCP-g-GO in the epoxy matrix could make epoxy not only stronger but also tougher.

Experimental results for a conventional cyclone and a modified cyclone with an adjustable vortex stopper are presented. The modified design is based on the idea of decreasing the surface friction by leaving a separation space between the cylindrical part and the vortex stopper. The measured pressure losses were compared for various exit pipe diameters, cylinder heights, cone bottom diameters, and inlet velocities for the conventional as well as for the modified design. The comparative studies indicate a similar behavior of the pressure loss coefficient for both cyclones. Additionally, the exit pipe diameter has a more significant effect on both cyclones compared to the other parameters. Increasing the length of the cyclone reduced the pressure losses for all cases examined.

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This study introduces the solar chimney power technology, which is a solar thermal energy system. One of the renewable energy resources, this system is an energy transformation system in which solar energy and wind energy are used together. In this system, the air that is heated with solar energy ensures the production of electric energy by moving upwards with the suction effect of the chimney and rotating the turbine that is placed inside the chimney. In this review, the main principles and characteristics of this system are discussed and the developments on the experimental and theoretical investigations carried out with regard to the solar chimneys around the world especially in recent years are shared with the readers. With the study, it is aimed to provide upto-date information to readers who are interested in this subject.

In this study, a multi-objective optimization method was used to improve the mechanical properties and manufacturing conditions of reinforced polyamide 66+PA6I/6T polymer based on injection molding process parameters. For that purpose, the combined approach of response surface methodology (RSM) and Grey Wolf Optimization (GWO) was proposed to minimize and model the quality parameters such as warpage, volumetric shrinkage, and cycle time of the polymer. In the study, Moldflow Insight software was used to simulate and obtain the numerical objective results based on design parameters including fiber ratio, mold temperature, melt temperature, injection pressure, and injection time. Based on optimized design parameters, a test specimen was produced in an injection molding machine to obtain and compare the tensile test results. The Box-Behnken method was applied for the experimental design of the numerical analysis, and the analysis of variance (ANOVA) method was used to investigate the effect of design parameters on the objective parameters in molding. According to the numerical results, it was found that both RSM and GWO methods gave better results than the quality results obtained by the recommended process parameter results as well as these results were consistent with the ANOVA results. It was determined that the RSM was more effective than the GWO method for this experimental design. Also, it was concluded that according to the experimental tensile test results, the best tensile test result was obtained by 60% fiber reinforcement, and the tensile module value increased by 39,4% for this addition ratio based on the optimized process parameters.