Broken heating

Figure 8-16 Broken Heating Curve From Simulation of Heat Transfer to a Canned Starch Dispersion at a Retort Temperature (/ 7) 101 °C. The og RT — T) versus time at the assumed slowest heating point and the corresponding fliud apparent viscosity (ija) versus time profiles are shown (Yang, 1997).

Estimated Heat Penetration Parameters and Broken Heating Phenomena... 

Stevens, P. M. 1972. Lethality calculations, including effects of product movement, for convection heating and broken heating foods in still-cook retorts. Ph.D. dissertation, Univ. of Massachusetts, Amherst, M A. 

Yang, W. H. and Rao, M. A. 1998c. Numerical study of parameters affecting broken heating curve. J. Food Eng. 36-37 43-61. 

Break point in broken heating heat penetration curve, s Heights above a reference point, m... 

Each SIS shall be periodically visually inspected to ensure there are no unauthorized modifications and no observable deterioration (for example, missing bolts or instrument covers, rusted brackets, open wires, broken conduits, broken heat tracing, and missing insulation). 

For indirect heat transfer, the heat integration characteristics of the reactor can be broken down into three cases ... 

Figure C2.5.6. Thennodynamic functions computed for the sequence whose native state is shown in figure C2.5.7. (a) Specific heat (dotted curve) and derivative of the radius of gyration with respect to temperature dR /dT (broken curve) as a function of temperature. The collapse temperature Tg is detennined from the peak of and found to be 0.83. Tf, is very close to the temperature at which d (R )/d T becomes maximum (0.86). This illustrates...

This equilibrium is established when hydrogen iodide is heated, hydrogen-iodine bonds being broken. 

Note. In the older types of Soxhiet extractor, an external tube ran from B up to the top of C for conveying the ascending column of hot vapour. This type had the disadvantage not only of being more easily broken, but also that the condensed liquid in C received very little heat, and therefore the extraction, being carried out by the lukewarm solvent, was usually very slow. 

Aliphatic ethers are broken down by heating with ZnClj. 

Formation of, -dinitrobenzoates. Aliphatic ethers are broken up by heating with ZnClg, and a 3,5--dinitrobenzoate of the residue can then be prepared. This is suitable only for symmetrical ethers. 

Place 18 g. (12 ml.) of fuming nitric acid, sp. gr. 1 5, and 30 g. (16-5 ml.) of concentrated sulphuric acid and a few fragments of broken glass in a 250 or 500 ml. round-bottomed flask. Add gradually, in small portions, 14 g. of p-nitrotoluene do not allow the temperature to rise above 50 and cool the flask, if necessary, by immersion in cold water. Place a small funnel in the mouth of the flask and heat on a water bath at 90-95° for 30 minutes. Allow to cool almost to the laboratory temperature and pour the reaction mixture slowly into about 500 ml. of ice water containing a few small pieces of ice. Filter the crude dinitrotoluene through a Buchner funnel at the pump, wash it thoroughly with cold water, and drain as completely as possible. RecrystalUse from the minimum volume of hot methyl alcohol (flask, reflux condenser, and water bath experimental details as in Section IV,12). The yield of pure 2 4-dinitrotoluene, m.p. 71°, is 12 -5 g. 

Burns caused by dry heat (e.g., by flames, hot objects, etc.). For slight bums in which the skin is not broken, apply tannic acid jelly ( Tannafax ), acriflavine jelly ( Bumol ) or butesin picrate ointment (butesin is re-butyl J aminobenzoate). 

After all the butter has been whisked in the sauce will be creamy and warm. If pools of clear butter oil have started pooling up all over the place the sauce has broken. You failed. Actually, the sauce will still taste fine, it just won t be creamy like a snooty Frenchman would like. The sauce can be kept warm over a hot water bath or by stirring over low heat. Anyway, at this point one stirs in the soy sauce and pineapple into the sauce and drapes it over the k-bobs. Oh God is it the best flavor in the world. You have been warned ... 

Thiazole disulfides are reported to yield quantitatively A-4-thiazoline-2-thiones under treatment with zinc powder in acetic acid (326). The disulfide bond can be broken on heating at 100 to 260°C and (or) by alkali. This property has been used for photographic emulsions (327). The disulfide (136) (R = 4-(D-arabmo-tetrahydroxybutyD can be cleaved readily by aqueous sodium hydroxyde. carbonate, or hydrogen carbonate (149) to give 135 a by-product, 4-(D-arabino-ietrahydroxybutyl) thiazole... 

In principle cis 2 butene and trans 2 butene may be mterconverted by rotation about the C 2=C 3 double bond However unlike rotation about the C 2—C 3 single bond in butane which is quite fast mterconversion of the stereoisomeric 2 butenes does not occur under normal circumstances It is sometimes said that rotation about a carbon-carbon double bond is restricted but this is an understatement Conventional lab oratory sources of heat do not provide enough energy for rotation about the double bond m alkenes As shown m Figure 5 2 rotation about a double bond requires the p orbitals of C 2 and C 3 to be twisted from their stable parallel alignment—m effect the tt com ponent of the double bond must be broken at the transition state... 

Alkyl hydrogen sulfates can be converted to alcohols by heating them with water This IS called hydrolysis, because a bond is cleaved by reaction with water It is the oxygen-sulfur bond that is broken when an alkyl hydrogen sulfate undergoes hydrolysis... 

With arcs, intense bombardment by ions and electrons and the heat produced at the electrodes cause sample molecules to be vaporized and broken down into their constituent elements. These sources are used particularly for analysis or isotope studies when the samples involved are inorganic, nonvolatile, and thermally very stable. 

Secondary. Scrap material, industrial and municipal wastes, and sludges containing mercury are treated in much the same manner as ores to recover mercury. Scrap products are first broken down to Hberate metallic mercury or its compounds. Heating in retorts vaporizes the mercury, which upon cooling condenses to high purity mercury metal. Industrial and municipal sludges and wastes may be treated chemically before roasting. 

Niobium pentoxide also is reduced to metal commercially by the aluminothermic process. The finely ground powder is mixed with atomized aluminum and an accelerator compound which gives extra heat during reaction, then is ignited. The reaction is completed quickly and, after cooling, the slag is broken loose to free the metal derby which is purified by electron-beam melting. 

Secondary bonds are considerably weaker than the primary covalent bonds. When a linear or branched polymer is heated, the dissociation energies of the secondary bonds are exceeded long before the primary covalent bonds are broken, freeing up the individual chains to flow under stress. When the material is cooled, the secondary bonds reform. Thus, linear and branched polymers are generally thermoplastic. On the other hand, cross-links contain primary covalent bonds like those that bond the atoms in the main chains. When a cross-linked polymer is heated sufficiently, these primary covalent bonds fail randomly, and the material degrades. Therefore, cross-linked polymers are thermosets. There are a few exceptions such as cellulose and polyacrylonitrile. Though linear, these polymers are not thermoplastic because the extensive secondary bonds make up for in quantity what they lack in quahty. 

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