Materials selection for radio frequency (RF) microelectromechanical (MEM) switches application is important for overall design and fabrication of devices. The processing techniques and microstructures of the materials in these devices differ from the techniques used in bulk structures. Although the properties and morphology of a bulk material may be well characterised, thin film materials have properties substantially different. MEM switches for RF and cryogenic applications has been developed where the switch is integrated in a coplanar waveguide on a LaAlO ₃ substrate as structure with a gold membrane bridge suspended above an area of the centre superconductor (YBa ₂ Cu ₃ O ₇ ) covered with a BaTiO ₃ dielectric. The gold (Au) membrane is actuated by the electrostatic attractive force acting between transmission line and the membrane when a dc control voltage is applied. The value of the actuation force greatly depends on the geometry and mechanical properties of the bridge material. A summary and review of the state‐of‐the‐art in MEM switches using Au membrane elements is presented and its application for cryogenic temperature is discussed.

A four yearlong air monitoring data (since 2015 to 2018) was collected to assess the impact of meteorological parameters such as temperature, relative humidity, wind speed and wind direction on the spatial and temporal variability of CO (carbon monoxide), NO₂ (nitrogen oxide), O₃ (ozone), SO₂ (sulfur dioxide), PM₁₀ and PM_2.5 (particulate matter with diameter aerodynamic less than 2.5 μm and 10 μm respectively) in Lima Metropolitan Area (LMA). Data from eight air quality monitoring stations, currently under the supervision of the National Meteorological and Hydrological Service (SENAMHI), was used to capture traffic - related pollutants concentrations under various local traffic conditions. Effects on meteorological events on seasonal traffic-related pollutants concentration variability were identified. Using average data from the eight stations, it was found that the monthly mean traffic-related pollutants since 2015 to 2018 were higher in spring and winter and lower in autumn and summer. Low-wind speed was associated with events that contribute to elevated seasonal PM_2.5 levels. Correlation coefficients between PM_2.5 concentrations and meteorological variables fluctuated significaly across different seasons. High PM_2.5 concentrations were associated with low relative humidity and high wind conditions in spring. Results suggest that there exist a seasonal variation of PM_2.5 concentration, and set the need of future work on the understanding of the air pollution effects on human health.