Cold air

Then remove the strip and dry it in a stream of cold air, either from a blower, or by pinning it to the lower edge of a fume-cupboard window having a vigorous draught already in operation. Then spray the strip lightly but uniformly with the ninhydrin solution (D) in a fume-cupboard, and dry as before. 

When three consistent readings are obtained, add a weighed pellet of the solute to T for this purpose it is important that the thermometer is not withdrawn, and the boiling is not interrupted. It is best to hold the pellet ready in a pair of forceps near the mouth of the side-arm of T, and then momentarily to remove the condenser, drop in the pellet and replace the condenser when the condenser is removed a small quantity of cold air entering the side-arm will cause slight condensation of the hot vapour, none of which will therefore escape. 

Provide Only the Heating or Cooling Actually Heeded. Generally, the supply temperature of hot and cold air, or water, should be reset according to actual need. This is especially important on systems or 2ones that allow simultaneous hea ting and cooling. 

Secondary smoke is produced mosdy by the condensation of water in humid or cold air. The presence of hydrogen chloride or hydrogen fluoride in the combustion products increases the extent and rate of condensation. Composition modifications to reduce primary smoke may reduce secondary smoke to some extent, but complete elimination is unlikely. The relatively small amount of smoke produced in gun firings by modem nitrocellulose propellants, although undesirable, is acceptable (102—109). 

Intrinsic asthma, also called idiopathic asthma, usually develops in adulthood. In intrinsic asthma allergic factors are not demonstrable. Episodes of intrinsic asthma may be triggered by a variety of stimuli, eg, emotional state, exposure to cold air, or inert dusts. Both intrinsic and extrinsic asthmatics can be prone to exercise-induced attacks. Individuals who experience a combination of extrinsic and intrinsic asthmatic reactions have mixed asthma. Status asthmaticus refers to an especially acute life-threatening asthma attack which is resistant to normal treatments and which may require hospitalization in order to stabilize the patient. 

The first SRS-A antagonist, FPL-55712 (26) (149), was discovered before the stmctures of the leukotrienes were detemiined. Although this compound is relatively weak as an antagonist and suffers from a very short half-life in vivo, it played an important role both in leukotriene stmcture elucidation and as a model for later antagonists. In work stmcturaHy related to FPL-55712, LY-171883 was developed (27) (150). LY-171883 was evaluated in several clinical trials before development was stopped. Orally adrninistered, LY-171883 blocked slightly the response to aerosol LTD improved pulmonary function (FEV ) in mild asthmatics (151), decreased the sensitivity of asthmatics to cold air-induced bronchoconstriction (152), and significantly reduced the bronchoconstrictor response to inhaled antigen (153). However, in all these studies the beneficial effects were minimal. 

Isobutjiene—isoprene elastomer (Butyl) has high resistance to oxidation, resists chemical attack, and is the elastomer most impervious to air. Because of these properties it is often used for protective garments, inflated air stmctures, cold air balloons, and fumigation covers. 

Fig. 7. Plant for spray-drying of detergents and soaps. 1, Burner 2, air combustion 3, cold air fan 4, hot air generator 5, spray-drying tower 6, cleaning ring 7, no22les circuit 8, tower suction cyclones group 9, tower suction fan 10, double-flap dischargers 11, recovery powder cyclone 12, recovery powder fan 13, belt conveyor 14, air lift 15, air lift suction cyclones 16, air lift suction fan 17, double-flip dischargers 18, vibrating sieve.

NOTE TLe fan on tLis dryer Landles about 5.2 mVs at outlet conditions. Tbe outlet-air temperature includes cold air in-leakage, and tbe true temperature drop caused hy evaporation must tberefore be estimated from a beat balance. 

Some materials that are prepared in the molten state are converted advantageously to flake form by cooling a thin layer continuously on the surface of a rotating drum. Another way is to spray cool from the melt, using a spray diyer with cold air. Thus, massive cooling and subsequent pulverizing are avoided. See the Index for details of these other methods. 

But blade cooling has reached a limit ducting still more cold air through the blades will begin to reduce the thermal efficiency by taking too much heat away from the combustion chamber. What do we do now ... 

Replacement of orchard heaters by wind machines is the most desirable control measure. These large propellers force the warmer air aloft to the ground, where it mixes with the cold air, minimizing frost formation. 

With this particular design, primary cooling is achieved by film cooling with cold air injected through small holes over the airfoil surface (Figure 9-21). The temperature distribution is shown in Figure 9-22. 

The injection of coolant air in the turbine rotor or stator causes a slight decrease in turbine efficiency however, the higher turbine inlet temperature usually makes up for the loss of the turbine component efficiency, giving an overall increase in cycle efficiency. Tests by NASA on three different types of cooled stator blades were conducted on a specially built 30-inch turbine cold-air test facility. The outer shell profile of all three blade types was the same, as seen in Figure 9-24. 

Behning, F.P., Schum, El.J., and Szanca, E.M., Cold-Air Investigation of a Turbine with Transpiration-Cooled Stator Blades, IV—Stage Performance with Wire-Mesh Shell Blading, NASA, TM X-2176, 1971. 

Moffitt, T.P., Prust, H.W. Jr., Szanca, E.M., and Schum, H.J., Summary of Cold-Air Tests of a Single-Stage Turbine with Various Stator Cooling Techniques, NASA, TM X-52969, 1971. 

Whitney, W.J., Szanca, E.M., Moffitt, T.P., and Monroe, D.E., Cold-Air Investigation of a Turbine for High-Temperature Engine Application, I— Turbine Design and Overall Stator Performance, NASA, TN D-3751, 1967. 

---