The Association between Weather Conditions (Ambient Air Temperature and Relative Humidity) with Coronavirus Disease (COVID-19) Risk in Bandar Abbas, Iran

Background: This study was devoted to evaluate the association between COVID-19 infection and weather conditions in Bandar Abbas, Iran. Methods: The positive cases data was retrieved from the Ministry of Health and Medical Education of Iran (MOHME) and weather conditions from the Iran meteorological organization (IMO) from the 01, October 2020 to 27, November 2020. The components of weather consist of average of the ambient air temperature (°C) and relative humidity (%). The Spearman correlation test was used to determine the association between weather conditions (temperature and relative humidity) with COVID-19 infection.Results: Spearman analysis showed that air temperature (Coefficient = -0.303 and P-value = 0.001) were negatively associated with COVID-19 infection. However, no significant association was observed between relative humidity (Coefficient = 0.088 and P-value = 0.340) and COVID-19 infection. Hence, the ambient air temperature can be considered as a considerable variable in the COVID-19 infection in Bandar Abbas. Conclusions: The results of this study can be used for prevention and control of COVID-19 infection in areas with similar meteorological conditions in world.

Ambient Air Temperature Assisted Crystallization for Inorganic CsPbI2Br Perovskite Solar Cells

Inorganic cesium lead halide perovskites, as alternative light absorbers for organic–inorganic hybrid perovskite solar cells, have attracted more and more attention due to their superb thermal stability for photovoltaic applications. However, the humid air instability of CsPbI2Br perovskite solar cells (PSCs) hinders their further development. The optoelectronic properties of CsPbI2Br films are closely related to the quality of films, so preparing high-quality perovskite films is crucial for fabricating high-performance PSCs. For the first time, we demonstrate that the regulation of ambient temperature of the dry air in the glovebox is able to control the growth of CsPbI2Br crystals and further optimize the morphology of CsPbI2Br film. Through controlling the ambient air temperature assisted crystallization, high-quality CsPbI2Br films are obtained, with advantages such as larger crystalline grains, negligible crystal boundaries, absence of pinholes, lower defect density, and faster carrier mobility. Accordingly, the PSCs based on as-prepared CsPbI2Br film achieve a power conversion efficiency of 15.5% (the maximum stabilized power output of 15.02%). Moreover, the optimized CsPbI2Br films show excellent robustness against moisture and oxygen and maintain the photovoltaic dark phase after 3 h aging in an air atmosphere at room temperature and 35% relative humidity (R.H.). In comparison, the pristine films are completely converted to the yellow phase in 1.5 h.

Maintenance Optimization of Wind Turbines Using Weather-Dependent Equivalent Age Model

Aging models are important input into wind farm maintenance and financial viability models. Aging of wind turbines depends on many factors, including both ambient and usage conditions. This paper presents a virtual age based maintenance model for wind turbines considering the effect of wind speed and ambient air temperature on turbine aging. Two maintenance thresholds (i.e., corrective threshold and preventive threshold) and three repair actions (i.e., unscheduled corrective, scheduled corrective and preventive actions) are integrated into the maintenance model. The objective is to determine the optimal thresholds values that minimize the expected total maintenance costs. A discreet time simulation model is developed to produce 20 years of weather and usage scenarios for a single onshore wind turbine. The optimization model is formulated as a mixed-integer nonlinear problem and solved using the Nelder–Mead method. A numerical example is presented to highlight the benefits of the proposed approach. Compared with traditional age-based maintenance, the proposed approach can achieve improvement in both availability and costs. The results show up to 50% reduction in maintenance cost as well as the significance of the effects of wind speed and ambient air temperature in maintenance planning.