Heat Producers

The rapid fission of a mass of or another heavy nucleus is the principle of the atomic bomb, the energy liberated being the destructive power. For useful energy the reaction has to be moderated this is done in a reactor where moderators such as water, heavy water, graphite, beryllium, etc., reduce the number of neutrons and slow those present to the most useful energies. The heat produced in a reactor is removed by normal heat-exchange methods. The neutrons in a reactor may be used for the formation of new isotopes, e.g. the transuranic elements, further fissile materials ( °Pu from or of the... [Pg.44]

Too rapid heating produces explosive decomposition. The reaction between hydroxyammonium chloride, NHjOH. Cl , and sodium nitrite gives pure dinitrogen oxide ... [Pg.228]

Measurements usually consist of a unit and a number expressing the quantity of that unit. Unfortunately, many different units may be used to express the same physical measurement. For example, the mass of a sample weighing 1.5 g also may be expressed as 0.0033 lb or 0.053 oz. For consistency, and to avoid confusion, scientists use a common set of fundamental units, several of which are listed in Table 2.1. These units are called SI units after the Systeme International d Unites. Other measurements are defined using these fundamental SI units. For example, we measure the quantity of heat produced during a chemical reaction in joules, (J), where... [Pg.12]

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. [Pg.39]

Heat produced in these cells operating at voltages of >2.31 V is generally removed by water evaporation and radiation losses. [Pg.484]

Induction heating is used to heat steel reactor vessels in the chemical process industry (5). The heat produced in the walls is conducted to the material within. Multisectioned cods are used to provide controlled heat input to the process material as it passes through the reactor. Figure 6 illustrates a cross section of such a typical installation. [Pg.128]

The hydrolysis of phosphoms sulfides has been studied quantitatively. A number of products are formed (Table 6). Whereas phosphoms(V) sulfide reacts slowly with cold water, the reaction is more rapid upon heating, producing mainly hydrogen sulfide and orthophosphoric acid, H2PO4. At high pH, P4S Q hydroly2es to a mixture of products containing thiophosphates and sulfides. [Pg.363]

The following discussion on health and safety aspects of titanium compounds is concerned only with the behavior of the titanium present in inorganic compounds and not with the effects of the compounds themselves. For example, titanium tetrachloride must be treated with care because of the effects of the hydrochloric acid and heat produced when it reacts with water, not because of the possible toxicity of titanium. Apart from very few exceptions, the inorganic compounds of titanium are generally regarded as having low toxicity. Because of the ubiquitous nature of the element and its compounds, average concentrations of titanium in blood have been determined at 130—160 Fg/L (182—184), with a typical value of 10 Fg/L in urine (185). [Pg.134]

The rate of chlorination of toluene relative to that of ben2ene is about 345 (61). Usually, chlorination is carried out at temperatures below 70°C with the reaction proceeding at a profitable rate even at 0°C. The reaction is exothermic with ca 139 kj (33 kcal) of heat produced per mole of monochlorotoluene formed. Chlorine efficiency is high, and toluene conversion to monochlorotoluene can be carried to about 90% with the formation of only a few percent of dichlorotoluenes. In most catalyst systems, decreasing temperatures favor formation of increasing amounts of -chlorotoluene. Concentrations of requited catalysts are low, generally on the order of several tenths of a percent or less. [Pg.54]

Enei y. In recent years the concern for energy conservation has resulted in many innovative process improvements to make the manufacture of citric acid more efficient. Eor example, heat produced by the exotherm of the neutralization of citric acid with lime is used in another part of the process where heat is requited, such as the evaporation/crystallization step. [Pg.183]

Most theories of droplet combustion assume a spherical, symmetrical droplet surrounded by a spherical flame, for which the radii of the droplet and the flame are denoted by and respectively. The flame is supported by the fuel diffusing from the droplet surface and the oxidant from the outside. The heat produced in the combustion zone ensures evaporation of the droplet and consequently the fuel supply. Other assumptions that further restrict the model include (/) the rate of chemical reaction is much higher than the rate of diffusion and hence the reaction is completed in a flame front of infinitesimal thickness (2) the droplet is made up of pure Hquid fuel (J) the composition of the ambient atmosphere far away from the droplet is constant and does not depend on the combustion process (4) combustion occurs under steady-state conditions (5) the surface temperature of the droplet is close or equal to the boiling point of the Hquid and (6) the effects of radiation, thermodiffusion, and radial pressure changes are negligible. [Pg.520]

Eady fusing systems, such as that used in the Xerox 914, employed radiant heat produced by incandescent lamps. Black toner is an extremely good... [Pg.139]

The additional heat generated by a negative sequence component may vary from six to ten times the theoretical heat produced by that amount of a positive sequence component, as analysed above. It is therefore more relevant to consider a factor of 6 to represent the effect of such a component. The heat generated can be rewritten as... [Pg.278]

Referring to Examples 12.2 and 12.3 above, the heat produced according to the empirical formula is as follows ... [Pg.279]

Thus these two methods will yield the same result for a negative sequence component of 40%. If the negative sequence current / is lower than 40%, the heat produced from equation (12.6) will be lower than the minimum heat obtained from equation (12.5). In contrast, for a negative sequence component of more than 40%, the situation is likely to be reversed, since the heat produced as in equation (12.6) will be higher than the maximum heat produced by equation (12.4). See the following example for more clarity. [Pg.279]

Transpiration is the movement of water from the root system up to the leaves and its subsequent evaporation to the atmosphere. This process moves nutrients throughout the plant and cools the plant. Respiration is a heat-producing process resulting from the oxidation of carbohydrates by O2 to form CO2 and H2O, as shown in Eq. (8-2). [Pg.112]

Thermal oxidation of graphite moderators is significant in several contexts. In the early air-cooled reactors the moderator temperature was low and hence the thermal oxidation rate was acceptable. However, the rate increased as the graphite became damaged by neutron irradiation. Moreover, the heat produced from the exothermic reaction... [Pg.472]

Thermal Hazards. These hazards include liot surfaces, fire produced by reacting substances, and flame contacts from heat-producing equipment, welding operations, and so on. [Pg.184]

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