Low-pressure area mesocyclones, but more often develop from environments of high instability and low vertical wind shear. In deserts, lack of ground and plant moisture that would normally provide evaporative cooling can lead to intense, rapid solar heating of the lower layers of air. The hot air is less dense than surrounding cooler air. This, combined with the rising of the hot air, results in a low-pressure area called a thermal low. Monsoon circulations are caused by thermal lows which form over large areas of land and their strength is driven by how land heats more quickly than the surrounding nearby ocean.
Low pressure molding Low pressure molding Low Pressure Molding (LPM) with polyamide and polyolefin (hot-melt) materials is a process typically used to encapsulate and environmentally protect electronic components (such as circuit boards). The purpose is to protect electronics against moisture, dust dirt and vibration. Low Pressure Molding is also used for sealing connectors and molding grommets and strain reliefs. Key to this process are the raw materials and specialized molding equipment. Dimer acid based polyamide materials, better known as hot-melts, are used as molding compounds. They are thermoplastics i.e. the material, when heated, becomes less viscous and is able to re-shaped, then hardens