Assignment 6: "Information Report – Revision"
bilnag
assignment_4_informative_draft.docxMECHANISM DESCRIPTION 1
MECHANISM DESCRIPTION 3
Mechanism description
William E. Nagy
08/06/2015
Professor Anna C. Morrison
ENG316
Strayer University:
The microwave
One of the most common home appliances is a microwave- used in cooking food using dielectric heating.
Below is a picture of a microwave.
Users guide
The users must place food on a container that is a poor conductor of heat. This reduces chances of the container busting as the food cooks at the microwave. The microwave has buttons used by the user to command the number of minutes that the microwave shall run. This depends with the convenient cooking time as per the manufacturers guide for the food being cooked. Foods that boil while cooking are not advised for cooking using a microwave.
Dielectric heating
Dielectric heating refers to a uniform alternating heating (mostly through radio waves) to a dielectric material. Unlike some heating methods where heat accumulates form one side, dielectric heating lead to uniform heating of food (all sides including top and bottom). A secondary importance of dielectric heating is that it kills pests and parasites in harvested crops.
The mechanism
The electric supply leads to movement of polar molecules that converge at an electromagnetic field that is subsequently created. The molecules move in one direction until the field alternates. The two movements are dipole rotation. Constant movement causes friction on the polar molecules leading to production of heat. This heat is used to uniformly heat food in the microwave. The insulating materials are used in passing heat energy. Their particles are affected by the changing current and increasing their temperature.
References
Hayden, S., Damm, M., & Kappe, C. O. (2013). On the importance of accurate internal temperature measurements in the microwave dielectric heating of viscous systems and polymer synthesis. Macromolecular Chemistry and Physics, 214(4), 423-434.
Zhu, X., Guo, W., & Wu, X. (2012). Frequency-and temperature-dependent dielectric properties of fruit juices associated with pasteurization by dielectric heating. Journal of Food Engineering, 109(2), 258-266.
