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Contact freezing uses physical contact other than air to transfer the heat. Direct contact freezing puts the product directly in contact with the refrigerant, while indirect contact freezing uses a plate in between. Plate freezing is the most common form of contact freezing. Food is put between cold metal plates and then lightly pressed to ...
Directional freezing can freeze water, from only one direction or side of a container, into clear ice. [ 1 ] [ 2 ] [ 3 ] Directional freezing in a domestic freezer can be done by putting water in a insulated container so that the water freezes from the top down, and removing before fully frozen, so that the minerals in the water are not frozen.
When solid objects like strawberries are freeze dried the original shape of the product is maintained. [19] If the product to be dried is a liquid, as often seen in pharmaceutical applications, the properties of the final product are optimized by the combination of excipients (i.e., inactive ingredients).
Finally there are the processes at the contact interface: compression and adhesion in the direction perpendicular to the interface, and friction and micro-slip in the tangential directions. The last aspect is the primary concern of contact mechanics. It is described in terms of so-called contact conditions. For the direction perpendicular to ...
Contact resistance values are typically small (in the microohm to milliohm range). Contact resistance can cause significant voltage drops and heating in circuits with high current. Because contact resistance adds to the intrinsic resistance of the conductors, it can cause significant measurement errors when exact resistance values are needed.
Perfect thermal contact supposes that on the boundary surface there holds an equality of the temperatures | = | and an equality of heat fluxes | = | where , are temperatures of the solid and environment (or mating solid), respectively; , are thermal conductivity coefficients of the solid and mating laminar layer (or solid), respectively; is normal to the surface .
An infectious disease agent can be transmitted in two ways: as horizontal disease agent transmission from one individual to another in the same generation (peers in the same age group) [3] by either direct contact (licking, touching, biting), or indirect contact through air – cough or sneeze (vectors or fomites that allow the transmission of the agent causing the disease without physical ...
In clouds warmer than about −37 °C where liquid water can persist in a supercooled state, ice nuclei can trigger droplets to freeze. [1] Contact nucleation can occur if an ice nucleus collides with a supercooled droplet, but the more important mechanism of freezing is when an ice nucleus becomes immersed in a supercooled water droplet and ...