ứng dụng sự nở vì nhiệt bằng tiếng anh

-The expansion and contraction of materials must be considered when designing large structures, when using tape or chain to measure distances for land surveys, when designing molds for casting hot material, and in other engineering applications when large changes in dimension due to temperature are expected -The thermal expansion of the solid has many practical applications and techniques: Eg: Balloon, thermometers, thermal relays in the iron, so that gaps in the monorail to not damage rails -The thermal expansion prevented can cause enormous momentum like fabricating dual band + Components: Two metal rods of different nature are frowned tight (tied by latches) together will constitute dual band + Features: dual tape were bent when cooled or heated when heated: dual tape kimloai curved toward less thermal expansion chillers when: tapes curved toward the metal dual thermal expansion than + Applications: used as thermal relay to close the circuit breaker when the temperature changes -Thermal expansion is also used in mechanical applications to fit parts over one another E.g a bushing can be fitted over a shaft by making its inner diameter slightly smaller than the diameter of the shaft, then heating it until it fits over the shaft, and allowing it to cool after it has been pushed over the shaft, thus achieving a 'shrink fit' -Thermal expansion of long continuous sections of rail tracks is the driving force for rail buckling This phenomenon resulted in 190 train derailments during 1998–2002 in the US alone -Thermal expansion can have a noticeable effect in gasoline stored in above ground storage tanks which can cause gasoline pumps to dispense gasoline which may be more compressed than gasoline held in underground storage tanks in the winter time or less compressed than gasoline held in underground storage tanks in the summer time Heat-induced expansion has to be taken into account in most areas of engineering A few examples are: • • • • • • • • Metal framed windows need rubber spacers Rubber tires Large structures such as railways and bridges need expansion joints in the structures to avoid sun kink One of the reasons for the poor performance of cold car engines is that parts have inefficiently large spacings until the normaloperating temperature is achieved A gridiron pendulum uses an arrangement of different metals to maintain a more temperature stable pendulum length A power line on a hot day is droopy, but on a cold day it is tight This is because the metals expand under heat Expansion joints that absorb the thermal expansion in a piping system Precision engineering nearly always requires the engineer to pay attention to the thermal expansion of the product For example, when using a scanning electron microscope even small changes in temperature such as degree can cause a sample to change its position relative to the focus point -Thermometers are another application of thermal expansion – most contain a liquid (usually mercury or alcohol) which is constrained to flow in only one direction (along the tube) due to changes in volume brought about by changes in temperature -Metal pipe leading hot gas or hot water must have a bend so that the pipe only deformed without fracture