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A shading device is integrated into a building in reducing the indoor solar heat gained. However, the incorporation of a shading device into an opening provides certain effects on indoor natural ventilation. Its performance in enhancing the indoor airflow is still arguable. For this reason, a comprehensive review was executed to identify the effects of a shading device on the natural ventilation of a building. A schematic review process was executed to identify the published articles that were related to the shading devices at the building openings. Subsequently, 25 articles have examined the shading devices at the building openings. The output parameters that were discussed including, the solar heat gained, temperature, energy consumption, daylighting, air quality, airflow, and thermal comfort. The studies agree that the shading device has certain effects on indoor airflow. The effects can be either good or detrimental, depending on the climatic condition, geographical location, building orientation, opening configuration, the shading function, and configuration. It is hoped that this review encourages more investigations of the combined effects of the shading device on solar radiation and natural ventilation. The combined effects are essential in achieving optimum performance of a shading device, which can reduce the solar radiation penetration and enhance the indoor natural ventilation. [ABSTRACT FROM AUTHOR]

Mineral-based oils are the market leaders when it comes to their consumption in different types of rotating machines. Recently, a lot of attention has been given to the bio-oils and lubricants due to their better thermophysical, tribological, and environmental characteristics for use in journal bearing and other rotating machines. The superior physical properties of bio-oils have instigated this research in order to evaluate their dynamic characteristics that can cause the harmful dynamic instabilities in rotating machinery. The dynamic characteristics of the fluid film are influenced by temperature, eccentricity ratio, and rotational speed. In this work, the effect of temperature is experimentally measured on the dynamic viscosity of bio-oils and mineral-based oil. The dynamic viscosity measured is then computationally used to estimate the hydrodynamic pressure response of three bio-oils (rapeseed, palm olein, and soybean) and SAE40, a mineral-based oil, to check their performance in the rotor bearing system. It is found that at 40 °C, the hydrodynamic pressure for SAE40 is observed to be 2.53, 2.72, and 3.32 times greater than those of rapeseed, palm olein, and soybean oil, respectively, whereas, at 125 °C, the hydrodynamic pressure for SAE40 is observed to be 8% and 4.3% less than those of rapeseed and palm olein, respectively, but 14% greater than that of soybean oil. Hence, the increasing temperature has less effect on the viscosity and hydrodynamic pressure of bio-oils compared to SAE40. Therefore, for high-temperature applications, the bio-oils can be used with further processing. The superior response of bio-oils is also an indication for better dynamic characteristics. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to simulate the influence of surface texturing produced via turning process toward pressure distribution and load capacity generation using computational fluid dynamics (CFD). Design/methodology/approach: The dimple geometry was obtained via turning process, to be used for future application on piston skirt surfaces. Two cases were studied: a preliminary study using single periodic dimple assuming linear dimple distribution and an application study using multiple periodic dimples to address actual dimple orientation following the turning process. Findings: For the first case, the dimple was proven to generate load capacity with regard to untextured surface, owing to the asymmetric pressure distribution. Increasing the Reynolds number, dimple width and dimple depth was found to increase load capacity. For the second case, although load capacity increases via surface texturing, the value was 97.4 per cent lower relative to the first case. This confirmed the importance of doing multiple dimple simulations for real applications to achieve more realistic and accurate results. Originality/value: A new concept of dimple fabrication using a low-cost turning process has been developed, with a potential to increase the tribological performance under hydrodynamic lubrication. Previous CFD simulations to simulate these benefits have been done using a single periodic dimple, assuming equal distribution array between dimples. However, due to the different orientations present for dimples produced using turning process, a single periodic dimple simulation may not be accurate, and instead, multiple dimple simulation is required. Therefore, present research was conducted to compare the results between these two cases and to ensure the accuracy of CFD simulation for this type of dimple. [ABSTRACT FROM AUTHOR]