Creado por cathy_shona
hace alrededor de 10 años
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Pregunta | Respuesta |
General material response to temperature? | As the temperature increases materials expand, the elastic modulus decreases as well as strength upon approaching the m.p. One melted the material has lost all strength and stiffness. |
Maximum Service Temperature | The maximum temperature a material can reach before risk of oxidation, chemical changes or excessive deformation. |
Minimum Service Temperature | The minimum temperature before a material becomes unsafe to use or too brittle to handle. |
Glass Transition Temperature | Temperature where the amplitude of vibration becomes so large that the VDW bonds become ineffective (amorphous) |
Heat Capacity | The energy required to raise the temperature of 1kg of material by 1K. (J/kg. K) |
Linear Thermal Expansion Coefficient | Measures the thermal strain per degree of temperature (K-1) |
Thermal Conductivity | Measures the flow of heat through a solid material in a steady-state (W/m .K) |
How do you measure Thermal Diffusivity? | can be calculated directly from the time taken for a known temperature pulse to travel a set thickness when the heat is applied briefly on one side. |
What makes a good Heat Exchanger? | must be able to transfer heat and withstand internal pressure from the fluids. (high thermal conductivity and yield strength) |
What makes a good insulator? | Minimize power loss (low thermal conductivity) |
What is the objective for a Storage Heater? | store as much heat per unit cost as possible. (also consider Tmax) |
What are the 3 processing families? | Shaping, Joining and Finishing |
What are the lower limits of Casting and Moulding? | Section thickness imposed by the physics flow. lrg SA=heat loss= premature cooling and solidification. |
How could you get very thin materials? | Either rolling or high pressure die-casting and molding methods. |
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