Heat, Excessive

In the initial stage of carbonization, it is critical to control the off-gases that evolve from the fiber as it is heated. Excessive heating rates result in void formation, stmctural dismption, and lower carbon fiber properties. 

Galled bores Improper removing techniques, insufficient or incorrect heating, excessive interference fit... 

Example 5. Glycolysis of Polyurethanes with Propylene Oxide after Pretreatment with Ethanolamine.55 A rigid polyurethane foam (ca. 100 g) was dissolved in 30 g ethanolamine by heating. Excess ethanolamine was stripped, leaving a clear solution. Infrared and GPC analysis indicated that the clear solution obtained contained some residual polyurethane, aromatic polyurea, aliphatic polyols, aromatic amines, and N,N -bis(f -hydroxyethyljurea. Next the mixture was dissolved in 45 g propylene oxide and heated at 120°C in an autoclave for 2 h. The pressure increased to 40 psi and then fell to 30 psi at the end of the 2-h heating period. The product was a brown oil with a hydroxyl number of485. 

The fuel cell station provides primary power for the facility as well as half of the hot water needed for heating. Excess electricity from the system flows back to the grid for use by other customers. 

After aeration for 3-5 days, flooding with heated excess liquid the charge will be heated to 55-60°C. The feeding orifice then will hermetically be closed and the anaerob digestion lasting 3-4 weeks will be started. During this process the temperature of the biomass will be reduced daily by 1-1°C, while at the end of digestion it will reach 30-... 

Curatives may be either solid or liquid at the processing temperature. Solid curatives such as MOCA or MCEDA are normally melted under controlled conditions prior to use. The manufacturers recommendations must be taken into account as to the temperature to which the material is heated. Excessive heating can cause breakdown of the materials, which is dangerous from a health and technical point of view. MOCA, if heated to 140°C, will start to decompose and give off dangerous fumes. The molten curatives can cause severe burns to the skin and absorption into the blood stream. 

When heated, the substance first melts, then turns into a paste, and finally solidifies. At higher temperatures or when heated excessively, the perchlorate decomposes further into potassium chloride and oxygen ... 

Lithium silicide, LigSi2.—By heating excess of lithium with silicon, and expelling the uncombined metal at 400° to 500° C., the silicide is obtained as a very hygroscopic, dark-violet, crystalline substance 8 of density 1 12. It is a very reactive product and a powerful reducer. With concentrated hydrochloric acid it yields spontaneously inflammable silicoethane, Si2H3, of which it may be considered a derivative. 

This reaction must be brought about by heating to 90° to 100° C., and takes place very rapidly in alcoholic as well as aqueous solution. The product of the reaction, sodium nitro methane disulphonate, forms small spheroidal plates, soluble with difficulty in cold water but easily in hot water. According to Rathke, if the reactants are heated excessively a salt is obtained which no longer contains the NO — group and to which he attributes the formula CH(S03Na)3. 

Mercury can also be lost after volatilisation, by adsorption and chemical reaction, as above. Adsorption is essentially a surface-area and temperature effect and so surface areas should be minimised. Absorption can be noticeable when plastic tubing is used for interconnections. Mercury is also lost if the release tube is heated excessively with vitreous silica this occurs at temperatures of around 900"C. 

The heat excess must be removed in a cooler (steam-generator). Placing the steam-generator before the FEHE allows heat recovery at higher temperature and is therefore preferable in view of exergetic considerations. 

The route to crosslinked phenol-formaldehyde resins via resoles corre.sponds to that used by Baekeland in his original commercial technique, They now tend to be used for adhesives, binders, and laminates. The resole prepolymers are made typically in batch processes, using a trace of ammonia (about 2% on phenol) as the alkaline catalyst. Care has to be taken with this process since, despite the molar excess of formaldehyde, there is sufficient of each component present in the prepolymer to permit the formation of a highly crosslinked product. Indeed, such a product will form if the resole is heated excessively, but the problem can be avoided by careful attention to the conditions of reaction and by ensuring that polymerisation is not allowed to proceed for too long. 

CH3CHICH3 + 2NH3 - CH3CH(NH3)CH3 + NH,I conditions heat excess of a concentrated solution of ammonia in ethanol with the halogenoalkane in a sealed tube. 

Heat Excessive heat and humidity Lowering of physiologic endurance... 

The ore hoisting equipment is a top mounted fiction hoist (Koepe winder) with a single skip and counterweight. The motor is air cooled and the heat excess from the motor during wintertime is used for heating up the headframe. The brake units are operated by 2 hydraulic systems. Main transformer, frequency converter and operator control system will be located in a separate building at ground level near the headframe. 

The Bischler-Mohlau indole synthesis is a classical chemical reaction that forms substituted indoles. The reaction involves heating excess anilines 1 with a-haloketones 2 (or a-haloacetals), followed by acid-catalyzed (aniline HX salt, X = Br or Cl, and Lewis acid) cyclization of the resulting intermediate 2-arylaminoketone. 

In 1881, Mohlau first disclosed this reaction, which was followed by further study carried out by Bischler in 1892-1893. Typically, this indole synthesis of heating excess anilines with a-haloketones is referred to as the Bischler reaction, however naming the transformation the Bischler-Mdhlau indole synthesis is more appropriate. Despite its long history, this classical reaction... 

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