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Heat lightning (not to be confused with dry thunderstorms, which are also often called dry lightning) is a misnomer [1] used for the faint flashes of lightning on the horizon or other clouds from distant thunderstorms that do not appear to have accompanying sounds of thunder.
Most of the electricity in an LED becomes heat rather than light – about 70% heat and 30% light. [1] If this heat is not removed, the LEDs run at high temperatures, which not only lowers their efficiency, but also makes the LED less reliable, shortens its lifespan. Thus, thermal management of high power LEDs is a crucial area of the research ...
The heat distortion temperature is determined by the following test procedure outlined in ASTM D648. The test specimen is loaded in three-point bending in the edgewise direction. The outer fiber stress used for testing is either 0.455 MPa or 1.82 MPa, and the temperature is increased at 2 °C/min until the specimen deflects 0.25 mm.
Therefore, the sunbeam hitting the ground at a 30° angle spreads the same amount of light over twice as much area (if we imagine the Sun shining from the south at noon, the north–south width doubles; the east–west width does not). Consequently, the amount of light falling on each square mile is only half as much. Figure 3
In polymers, such as plastics, thermal degradation refers to a type of polymer degradation where damaging chemical changes take place at elevated temperatures, without the simultaneous involvement of other compounds such as oxygen.
Heat domes can arise in still and dry summer conditions, when a mass of warm air builds up, and the high pressure from the Earth's atmosphere pushes the warm air down. The air is then compressed, and as its net heat is now in a smaller volume, it increases in temperature.
Differentiated phosphor degeneration: The different phosphors used in white LEDs tend to degrade with heat and age, but at different rates causing changes in the produced light color, for example, purple and pink LEDs often use an organic phosphor formulation which may degrade after just a few hours of operation causing a major shift in output ...
The amount of Sun energy reaching a location on Earth ("insolation", shown in blue) varies through the seasons.As it takes time for the seas and lands to heat or cool, the surface temperatures will lag the primary cycle by roughly a month, although this will vary from location to location, and the lag is not necessarily symmetric between summer and winter.