Design and Optimization for Mounting Primary Mirror with Reduced Sensitivity to Temperature Change in an Aerial Optoelectronic Sensor

In order to improve the image quality of the aerial optoelectronic sensor over a wide range of temperature changes, high thermal adaptability of the primary mirror as the critical components is considered. Integrated optomechanical analysis and optimization for mounting primary mirrors are carried out. The mirror surface shape error caused by uniform temperature decrease was treated as the objective function, and the fundamental frequency of the mirror assembly and the surface shape error caused by gravity parallel or vertical to the optical axis are taken as the constraints. A detailed size optimization is conducted to optimize its dimension parameters. Sensitivities of the optical system performance with respect to the size parameters are further evaluated. The configuration of the primary mirror and the flexure are obtained. The simulated optimization results show that the size parameters differently affect the optical performance and which factors are the key. The mirror surface shape error under 30 °C uniform temperature decrease effectively decreased from 26.5 nm to 11.6 nm, despite the weight of the primary mirror assembly increases by 0.3 kg. Compared to the initial design, the value of the system’s modulation transfer function (0° field angle) is improved from 0.15 to 0.21. Namely, the optical performance of the camera under thermal load has been enhanced and thermal adaptability of the primary mirror has been obviously reinforced after optimization. Based on the optimized results, a prototype of the primary mirror assembly is manufactured and assembled. A ground thermal test was conducted to verify difference in imaging quality at room and low temperature, respectively. The image quality of the camera meets the requirements of the index despite degrading.

Investigating the impacts of shaded outdoor spaces on thermal adaptation and cognitive performance of children in classroom environments

<p>The effects of green areas and shading strategies have been identified as an effective means to reduce urban risk factors such as the Urban Heat Island (UHI) effect. Even though the importance of shaded outdoor spaces and thermal comfort have been well documented in the existing literature; there is still limited research on how these spaces can influence thermal adaptability and cognitive performance in primary school children.</p><p>As a result, the aim of the study is twofold: (1) to evaluate the effect of outdoor shaded spaces upon thermal comfort; and, (2) link such results upon the cognitive performance of primary school students in a classroom environment with natural ventilation. A case study shall be conducted with primary school students between the ages of 8-10 in the Bilkent Primary School in Ankara during the month of September.</p><p>The quantitative thermal microclimatic conditions of unshaded/shaded areas of the schoolyard and indoor classrooms are obtained through the Physiologically Equivalent Temperature (PET) index. The qualitative evaluation of thermal comfort is undertaken by using both the adaptive model, and a complementary thermal sensation survey. As a result, both human physiological and psychological attributes of thermal comfort adaptation shall be evaluated and cross-examined in the study. Attention and memory tasks are given to the respondents in order to measure the cognitive performance of the students that are subjected to different experiences of outdoor shading levels.</p><p>The outcome of this individual study shall pinpoint the contributions of shaded outdoor green spaces upon the thermal adaptability and cognitive performance of children within classroom settings.</p>