thermal hazard

Examples of thermal hazard in the following topics:

• Humans and Electric Hazards

  • The hazards from electricity can be categorized into thermal and shock hazards.
  • There are two known categories of electrical hazards: thermal hazards and shock hazards.
  • A thermal hazard is when excessive electric power causes undesired thermal effects, such as starting a fire in the wall of a house.
  • A thermal hazard can be created even when a short circuit is not present if the wires in a circuit are overloaded with too much current.
  • Thermal hazards can cause moderate to severe burns to those who come in contact with the affected appliance or circuit.

• Safety Precautions in the Household

  • Electrical safety systems and devices are designed and widely used to reduce the risks of thermal and shock hazards.
  • Electricity has two hazards.
  • A thermal hazard occurs in cases of electrical overheating.
  • A shock hazard occurs when an electric current passes through a person.
  • There are many systems and devices that prevent electrical hazards .

• Thermal Stresses

  • Solids also undergo thermal expansion.
  • What are the basic properties of thermal expansion?
  • What is the underlying cause of thermal expansion?
  • Thermal stress is created by thermal expansion or contraction.
  • Another example of thermal stress is found in the mouth.

• The Zeroth Law of Thermodynamics

  • The Zeroth Law of Thermodynamics states that systems in thermal equilibrium are at the same temperature.
  • Systems are in thermal equilibrium if they do not transfer heat, even though they are in a position to do so, based on other factors.
  • If A and C are in thermal equilibrium, and A and B are in thermal equilibrium, then B and C are in thermal equilibrium.
  • Temperature is the quantity that is always the same for all systems in thermal equilibrium with one another.
  • The double arrow represents thermal equilibrium between systems.

• A Review of the Zeroth Law

  • The Zeroth Law of Thermodynamics states: If two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C.
  • Two systems are in thermal equilibrium if they could transfer heat between each other, but don't.
  • Indeed, experiments have shown that if two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system C, then A is also in thermal equilibrium with C.
  • The answer lies in the fact that any two systems placed in thermal contact (meaning heat transfer can occur between them) will reach the same temperature.
  • The objects are then in thermal equilibrium, and no further changes will occur.

• Thermal Radiation

  • $\displaystyle \text{Another Kirchoff's Law: }S_\nu = B_\nu(T) \text{ for a thermal emitter}$
  • Because $I_\nu=B_\nu(T)$ outside of the thermal emitting material and $S_\nu=B_\nu(T)$ within the material, we find that $I_\nu=B_\nu(T)$ through out the enclosure.
  • If we remove the thermal emitter from the blackbody enclosure we can see the difference between thermal radiation and blackbody radiation.
  • A thermal emitter has $S_\nu = B_\nu(T)$,$B_\nu(T)$ so the radiation field approaches $B_\nu(T)$ (blackbody radiation) only at large optical depth.

• Thermal Pollution

  • Thermal pollution is the degradation of water quality by any process that changes ambient water temperature.
  • Thermal pollution is the degradation of water quality by any process that changes ambient water temperature.
  • Some fish species will avoid stream segments or coastal areas adjacent to a thermal discharge.
  • Some may assume that by cooling the heated water, we can possibly fix the issue of thermal pollution.
  • Identify factors that lead to thermal pollution and its ecological effects

• Linear Expansion

  • Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.
  • Thermal expansion is the tendency of matter to change in volume in response to a change in temperature.
  • This kind of excitation is called thermal motion.
  • The degree of expansion divided by the change in temperature is called the material's coefficient of thermal expansion; it generally varies with temperature.
  • Thermal expansion of long continuous sections of rail tracks is the driving force for rail buckling.

• Thermal Bremsstrahlung Emission

  • The most important case astrophysically is thermal bremsstrahlung where the electrons have a thermal distribution so the probablility of a particle having a particular velocity is
  • ${\bar g}_{ff}$ is the thermally averaged Gaunt factor.
  • Thermal bremsstrahlung spectra for two temperatures that differ by a factor of ten

• Area Expansion

  • Objects expand in all dimensions, and we can extend the thermal expansion for 1D to two (or three) dimensions.
  • If the metal is heated, we can guess that the the piece, in general, will get larger due to thermal expansion.
  • The area thermal expansion coefficient relates the change in a material's area dimensions to a change in temperature.
  • For isotropic materials, and for small expansions, the linear thermal expansion coefficient is one half of the area coefficient.
  • Express the area thermal expansion coefficient in the form of an equation