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In this study, a numerical and experimental analysis of a solar collector with roughness elements in the form of stainless-steel scourers on the absorber surface is presented. According to the location type and number of the stainless steel scourers, the absorber surfaces are referred to as the complex surface (C1), less complex surface (C2), and flat surface (C3). A Computational Fluid Dynamics (CFD) analysis was carried out using ANSYS-CFX-R18.2 commercial software. The results were verified with the experimental study. After the numerical study was confirmation with the experimental study, then the detailed investigation was performed by numerical simulations. The extracted results of the numerical and experimental analysis concerned the air temperature and velocity, and thermal efficiency, which varied with respect to the type of collector. As a result, the C1 type yielded the highest air velocity and air temperature, while the lowest values of air velocity and temperature were recorded for the C3 type, according to both the numerical analysis and experimental tests. This trend was similar for the efficiencies. The efficiency was nearly 80% for collectors with stainless-steel scourers, whilst it was 55% for the flat plate collector. The results showed that the experimental and numerical results agreed well. [ABSTRACT FROM AUTHOR]

Expanded clay (exclay) aggregate and cherry tree resin are used in this study to produce a lightweight construction material. Based on the grain diameter, exclays are classified as d = 2–4 mm and d = 4–6 mm. Cement is added to each group as the binder material. The exclay ratios vary as 10%, 20%, 30%, 40% and 50% of the total volume in the samples. The cherry tree resin is poured into the concrete mixture with a ratio of 1% and 1.5% of cement + exclay mixture in order to form artificial pores in each sample group. The produced samples are subjected to some tests, such as thermal conductivity, water absorption and compressive strength. It is determined that due to the increase in exclay ratios and particle diameter, there is an increase in porosity along with water absorption, but there is a decrease in density, thermal conductivity and compressive strength. Hence, these newly produced concretes are recommended for panel walls, brick, concrete briquettes, inner and outer plaster and concrete partition elements. [ABSTRACT FROM AUTHOR]

In this study, the drying of kiwi fruit in a convective dryer is examined experimentally. Air velocity, thickness of the slices and drying time are the varied parameters in drying process. In the experimental study, kiwi slices having thickness of 4 and 8 mm are dried in the dryer under the conditions of 45 °C temperature of the drying air, 10% relative humidity and 0.5–1.5 m/s drying air velocity. In addition to the tests, the effects of mentioned drying parameters on drying are analyzed by ANOVA (Analysis of Variance) method to find the contribution rate of each parameter. For this aim, an orthogonal array is arranged by using Taguchi design of experiment method. As the results of experiments and variance analysis, it has been determined that, drying air velocity plays a significant effect on total drying time. The minimum drying time (225 min) is achieved for 1.5 m/s for 4 mm slices, and the maximum drying time (750 min) is achieved for 0.5 m/s for the kiwi sample sliced 8 mm thick. It is also concluded that, working with the convective dryer at different velocities is advantageous in terms of preserving brightness and color quality. [ABSTRACT FROM AUTHOR]

In present study, to investigate the thermal effects of the rechargeable neuromodulation implants (an implant and antenna together) in the body, a numerical analysis is performed by using commercial software ANSYS. Since it is well established that both the antenna and the implant generate heat, both of these heat sources may increase the tissue temperature in the subcutaneous zone and may also increase the temperature in the deeper tissue. Therefore, the sizes and heat generation amounts of the implant-antenna system gain great importance and a parametric evaluation that shows the effects of the design parameters on the temperature becomes necessary. For this aim, an optimization study is performed. The runs of the numerical simulations are determined by well-known design analysis method, namely Taguchi and the parametric evaluation of the study is carried out by Analysis of Variance (ANOVA) method. The design parameters considered are; ( i) heat generated by the antenna q (50, 52 and 54 W/m), ( ii) heat generated by the implant q (30 and 35 W/m), ( iii) thickness of the implant t (9, 11, and 13 mm) and finally ( iv) the radius of the antenna R (31, 35, 39 mm). The results showed that higher antenna radii result in higher temperatures in the tissue, whilst the least effective design parameter on the temperature is the heat generation of the implant. [ABSTRACT FROM AUTHOR]