Cooling packs

EDTA-treated or heparinized blood (3-5 ml) can be used for the isolation of leukocytes. Blood should be sent by express mail to ensure rapid transport. During the summer months, cooling of the samples is required (e.g., frozen cooling packs... 

Endothermic processes are common in our everyday experience. Examples include the melting of ice cubes in a glass of water, or the evaporation of sweat from our skin. In these cases, the greater entropy of the products favors the utilization of energy to allow these processes to occur (Case III). A dramatic example is a chemical cooling pack that contains a salt (usually ammonium nitrate,... 

To illustrate the problem of thermal sensitivity we will analyse the simple one-dimensional model of the countercurrent cooled packed tubular reactor described earlier and illustrated in Fig. 3.25. We have already seen that the mass and heat balance equations for the system may be written ... 

Two other cases of oxaliplatin extravasation have been reported (233). Both occurred when the intraport needle disconnected. The initial symptoms were swelling and tenderness at the port site. The patients developed severe inflammation after 3 days. Treatment included local cool packs, diclofenac ointment, and oral indometacin, morphine, or dexamethasone. The authors avoided saline instillation because sodium chloride and oxaliplatin may be incompatible in combination (119). Both patients recovered without any sign of local necrosis and longterm sequelae (233)... 

This cooling effect is made use of in cooling packs for first aid. The inner bag in the pack contains water which is colored blue, while the pack itself contains solid ammonium nitrate. When the cooling effect is required the inner bag is pressed hard so that it bursts and the water can mix with the salt. Commercial packs contain about 220 g NH4NO3 and an equal amount of water the temperature falls from +20°C to about -7°C, a temperature which is sufficiently low for cooling body organs. 

Tell the client to apply cool packs to the eye after instilling medication. 

One application of reactions that take in or give out heat is in cooling packs (Box 13.1). 

J. G. H. Borkink, K. R. Westererp, Significant of the radial porosity profile for the description of heat transport in wall-cooled packed beds, Chem. Eng. Sci, 49, S63-ST6 (1994). 

Figure4.10.67 Radial temperature profile in a cooled packed bed reactor according to the two-dimensional model (consideration of radial and axial T-proflles).

We are now able to derive some characteristic temperature differences related to a cooled packed bed with chemical reaction. The temperature difference within the bed and the one directly at the internal wall are according to Eqs. (4.10.187) and (4.10.174) related by ... 

Figure 6.2 Using a cooling pack to treat a sports injury. When the pack is kneaded, water and ammonium chloride crystals mix. As the crystals dissolve, energy is transferred from the surroundings, cooling the injury.

When the cavity is full, the pressure on the molten plastic is increased to add more material into the cavity in compensation for the shrinkage caused by cooling (packing stage). 

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