During freezing

Freeze Point Depression. The slight heat-transfer penalty incurred when an antifreeze is added to the aqueous heat-transfer fluid is necessitated by the need for increased operating temperature range in most internal combustion engines. Because most parts of the world achieve temperatures below freezing during some time of the year, an antifreeze fluid is required to keep equipment operational in these subfreezing temperatures. 

Figure 16. Schematic of the geometry of a section of liver before (top) and after (bottom) being subjected to slow freezing. During slow freezing, ice forms in the sinusoids and water flows osmotically from the cells into the sinusoids. (The upper drawing is slightly modified from Rubinsky and Pegg, 1988.)...

It must also be remembered that feed solutions that are allowed to stand for any length of time (such as when they are shipped from one place to another) may behave in quite different ways from a freshly prepared feed solution in the SX circuit. Furthermore, solutions shipped in cold climates may freeze during shipment, and this may result in problems in SX, such as emulsion formation, that would not occur if freshly prepared solutions were employed. The preparation and treatment of feed solutions for small-scale and pilot operations are important considerations in scale-up, and failure to recognize this may well result in considerable problems in the final plant. 

The US Navy also used conductive rubber blankets over fire control equipment to prevent fogging freezing during cold weather. The elec current carried by the blanket produced enough heat to keep the equipment in operation... 

These designs have provisions for the removal of noncondensable vapors and air, for the prevention of freezing during cold weather. Excessive buildup of noncondensable vapors in the main condenser would prevent effective condensation. Protection against ice formation is usually accomplished by warm air recirculation and/or fan control. Condensed steam from cooling coils flows by gravity to condensate receivers and is pumped back to the feedwater circuit by a condensate pump. 

The water main in the cities must be placed at sufficient depth belotv the earth s surface to avoid freezing during extended periods of subfreezing temperatures. Determine the minimum depth at which the water main must be placed at a location where the soil is initially at IS°C and the earth s surface temperature under the worst conditions is expected to remain at — lO C for a period of 75 days. Take the properties of soil at that location to be k = 0.7 W/m °C and a = 1.4 X 10 mVs. Answer 7.05 m... 

C Consider a shallow body of water. Is it possible for this water to freeze during a cold and dry night even when the ambient air and surrounding suiface temperatures never drop to 0"C Explain. 

Systems filled with biphenyl-diphenyl oxide mixtures or inorganic salt should be heat traced to avoid freezing during cool down to ambient temperature. This is very important because severe pump failure can occur and restarting of the system will be extremely difficult. 

How are bears able to stay warm enough to keep from freezing during their winter hibernation How do marathon nmners get the energy to finish a race without stopping to eat In both cases, fats stored in the body are oxidized. Oxygen molecules from the air are reduced as they gain electrons to form water. In a series of redox reactions called respiration. 

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