Heat development, 2.18

An interesting experimental technique is heat development of nuclei. The liquid is held at the desired temperature for a prescribed time, while nuclei accumulate they are then made visible as crystallites by quickly warming the solution to a temperature just below Tq, where no new nuclei form but existing ones grow rapidly. 

Note 1. The heat developed by the reaction is just enough to cause gentle refluxing, provided that the mixture is not stirred too vigorously. If refluxing stops during the addition, external heating must be applied. 

Thermal conductive backing material to dissipate heat developed in oil film. 

Frictional heat develops rapidly in some units such as a Baubuiy mixer. The first temperature rise may be beneficial in softening the materials and accelerating chemical reactions. High temperatures detrimental to the product may easily be reached, however, and pro-... 

Determine the inter-dependence of reaction rate and variables, establish the limiting values to prevent undesirable reactions, excessive heat development etc. 

One day the operator closed the remotely operated valve in the air line but did not consider it necessary to close the hand valve as well, although the instructions said he should. The remotely operated valve was leaking, the air met the reactor contents in the feed line, and reaction took place there. The heat developed caused the line to fail, and a major fire followed. 

An entirely different diesel hazard is compression of a pocket of air and flammable vapor trapped in a vessel or pipeline by a column of liquid. If the pressure of the liquid rises, the air is compressed, and the heat developed may heat the vapor above its auto-ignition temperature [13]. 

Caused by fhctional heat developed by pressure and slippage, regardless of drilling depth. 

Let ado be the heat developed per second in a portion of a homogeneous conductor the ends of which are at temperatures 6 and 6 + d6, when unit current passes from the warmer to the colder end. a is called the specific heat of electricity in the metal. Let the values of [Pg.451]

The oxygen in the blast penetrates but a short distance above the tuyere level. It is all consumed in burning the carbon of the coke to CO. Most of the carbon in the coke descends through the shaft of the furnace until it reaches the tuyere zone, where it is met by the blast and burned to carbon monoxide. The high temperature precludes the formation of carbon dioxide. Some of the carbon, however, through actual contact with iron oxide, is oxidized (either to CO or C02) in the upper part of the furnace. This oxidation, of course, liberates heat above, instead of in, the smelting zone where it is most needed and likewise tends to decrease the proportion of carbon fully oxidized to C02 in the furnace and thereby the quantity of heat developed in the furnace. 

The kinetic results and related analysis (2) summarized above indicate that there is a change in the predominant class of oxidation reaction with increasing temperature, which led to the expectation that the total heat developed in the overall oxidation also depends on temperature. Because the measurements that led to kinetic data based on initial rates were continued nearly isothermal ly until oxidation was complete, it has also been possible to establish (2) that the total heat developed increased by nearly ten-fold over the range 155 to 320°C. 

Literally removal , but applied particularly in space technology to the process of using up the frictional heat developed on re-entry of the vehicle into the Earth s atmosphere by degradation of the heat shield. Certain thermoplastics, thermosetting resins and polytetrafluoroethylene have been evaluated as ablative materials. 

Forest products industries know that temperature increases in piles of sawdust and bark. In pulp and paper mills, self-heating develops in amassed tree chips. Paper rolls stacked hot tend to self-heat, as occasionally do stored bales of waste paper. The wood-base panel products particleboard, hardboard, and fiberboard self-heat after being stacked too hot in the factory. Where in structures the framing lumber, wood-base panels, and lignocellulosic insulation is heated by items such as steam pipes, temperatures tend to rise above that of the heat source. 

It must also withstand the heat developed when dispersed. 

Airco A modification of the Deacon process for oxidizing hydrogen chloride to chlorine. The copper catalyst is modified with lanthanides and used in a reversing flow reactor without the need for external heat. Developed by the Air Reduction Company from the late 1930s. U.S. Patents 2,204,172 2,312,952 2,271,056 2,447,834. 

Outokumpu [Named after a hill in Finland, near Kuusjarvi] A flash-smelting process for sulfide ores, ft is an energy-efficient process (also called an autogenous process), using mainly the heat of combustion of the contained sulfur to sulfur dioxide, rather than ary external source of heat. Developed R Bryk and J. Ryselin at the Haijavalta works of Outokumpu Oy, Finland, in 1946. Used mainly for copper ores, but also for nickel, iron, and lead by 1988, 40 plants were using the process worldwide. 

Sobolcvsky A process for converting native platinum to malleable platinum by pressing and heating. Developed by P. G. Sobolevsky in Russia in the 1820s. 

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