Heat, general

Heat pipes. The use of heat pipes involves the incoming cold air stream and the outgoing warm air stream being immediately adjacent and parallel, and between the two is a battery of heat pipes. These contain a liquid and operate on the thermal siphon principle. The liquid takes in latent heat and evaporates and the vapor travels to the cold end of the tube where condensation releases the latent heat. Generally, heat pipes are restricted to 400°C, and effectiveness can be up to 70 per cent. 

Emulsion cleaners can be used hot or cold. Heat generally improves the cleaning action but, in most cases, leads to an objectionable increase in the smell associated with solvent products. 

Induction heated general purpose plant only Water-jacketted reactor only... 

Selective heating generally means that in a sample containing more than one component, only that component which couples with microwaves is selectively heated. The nonabsorbing components are not thus heated directly but only by heat transfer from the heated component. For example ... 

CE instruments are thermostated to dissipate excessive Joule heat. Generally that covers only the main part of the capillary, and not, e.g., the autosampler with the buffer and sample vials. In some instruments, it is difficult to control the autosampler temperature due to the near presence of extraneous heating sources such as the detector lamp. Also, some labs... 

To accomplish the thermal desorption, contaminated media are heated, generally between 300 and 1000°F, thus driving off the water, volatile contaminants, and some semivolatile contaminants from the contaminated media and into the off-gas stream. The removed contaminants are then treated by thermal oxidation in an afterburner, condensed in a single- or multiple-stage condenser, or captured by carbon adsorption beds. 

Mayow advances many speculations as to the functions of the nitro-aerial spirit, which show that he does not distinguish clearly between this spirit and the phenomena of heat generally, as in producing rigidity in bodies, and in affecting their elasticity, and that the elastic power of air is due to nitro-aerial spirit. He arrives at these conclusions on the basis of experiments described, but often misinterpreted. 

Divalent and tetravalent Pt probably form as many complexes as any other metal. The platinum(II) complexes are numerous with IV. S, halogens, and C. The letranitritoplatinum complexes are soluble in basic solution. Tetranitntoplatinum(II) ion is formed when a solution of plat-inum(II) chloride is boiled, at about neutral pH, with an excess of NaNO f. The ammonium salt may explode when heated. Generally, platinum-metal nitrites should be destroyed in solution. They never should be heated in the dry form. Pladnum(II) complexes most often have a coordination number of 4. Many compounds have been prepared with olefins, cyanides, nitriles, halides, isonitnles, amines, phosphines, arsines, and nitro compounds. 

Table 4.7 Temperature range of controlled heating (general method TsUrt -Tentl) and residence time (tmax) at maximum temperature 7max...

Recently, a study was made of the electrophoretic as well as other physical and chemical properties of three types of soybean protein fractions (19). It was found that heating generally reduced the solubility of a suspension of these fractions and also increased their viscosity. These changes were attributed to subunit dissociation and aggregation. 

The reaction of aromatic halides with tertiary phosphines requires special reaction conditions, as they are not susceptible to the simple nucleophilic substitution reaction. Strong heating, generally in a closed pressure tube, with the tertiary phosphine in the presence of a nickel(II) halide salt allows substitution of the halogen by phosphorus, probably by way of an addition-elimination reaction. 

Heat generally accelerates the process of free radical formation and the subsequent reaction steps... 

The bake systems polymerize by heat generally requiring temperatures which range between 350° to 400°F (177° to 204°C). This type of formulation is normally applied by dip or spray application to a film thickness ranging from 1 mil to 8 mils. Generally, this system produces a very hard finish although they can be formulated to produce a degree of flexibility, such as those systems used for container liners. 

In Sec. 18.4 we contrasted physical properties of carboxylic acids with those of their salts amines and their salts show the same contrast. Amine salts are typical ionic compounds. They are non-volatile solids, and when heated generally decompose before the high temperature required for melting is reached. The halides, nitrates, and sulfates are soluble in water but are insoluble in non-polar solvents. 

See Binding mechanism (Section 2.2). Technique involving induration of green agglomerate by heat. Generally, bonding at a temperature below the melting point of the main constituent by application of heat. 

If the substance undergoing calcination is fusible, it is necessary when quantities are to be ascertained, to weigh both the crucible and contents before Ignition, so that the amount of volatile matter driven off may be expressed by the weight lost in heating. Water alone or acidulated, with the aid of heat, generally removes the calcined matter from the crucible. 

Considerable improvement in the materials used for glazing will be required before the reflection and reradiation losses can be reduced sufficiently to make this means of obtaining heat generally economically attractive. 

It is the acid content of fruit that most aids their preservation by heat. Generally speaking the greater the acid content the less the exposure to heat required to sterilize. Biglow and Dunbar designate the kind of acid in fruit juices as follows ... 

But if we program the temperature in a linear manner, the sample temperature also increases linearly. The rate of heating generally used for most inorganic materials ranges between about 2° to 20°/min. while that for organic compounds lies between about 15° to 100°/min. 

The ability of a material to resist chemical attack (the attack is dependent on the method of test and its severity and is measured by determining the changes in physical properties [ASTM, 1982]. Reaction of a substance with oxygen with release of heat, generally accompanied by flaming and/or emission of smoke. Any chemical process that produces light and heat, either as glow or flame. 

---