Temperature-sensitivity

The temperature sensitivity of a propellant is always discussed in connection with  

1) the initial temperature sensitivity of the burn rate r (at constant pressure), 

Temperature sensitivity is a measure of change in burn rate with respect to initial temperature of propellant at constant pressure. It is designated as ( r)p and is derived from Vielle s equation, that is, the mathematical derivation of ( ) is (Equation 4.12)  

The chamber pressure of the motor also changes due to the change in initial temperature of propellant for a fixed nozzle. This coefficient (temperature sensitivity of pressure at constant k) is expressed as (Equation 4.13)  

Many chemicals are degraded when heated to moderate temperatures for relatively short times. When evaporating such materials special techniques are needed to control the time/temperature characteristics of the evaporator system. 

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CAUTION - The lower nitroalkanes form shock and/or temperature sensitive EXPLOSIVE compounds with amines and hydroxides. BE CAREFUL, DAMNIT You have been warned. 

When prepared using a saturated solution of KCl, the Ag/AgCl electrode has a potential of +0.197 V at 25 °C. Another common Ag/AgCl electrode uses a solution of 3.5 M KCl and has a potential of +0.205 at 25 °C. The Ag/AgCl electrode prepared with saturated KCl, of course, is more temperature-sensitive than one prepared with an unsaturated solution of KCl. 

Fig. 6. Thermograph of a person in the 3 to 5 ]lni spectral band. Spatial resolution is 1 mm and temperature sensitivity is 0.1°C.

Fig. 7. Thermographic image of a power distribution station and transformer. Spatial resolution is 0.3 m-radians and temperature sensitivity is 0.08 C.

Process Concepts. Hybrid systems involving gas-phase adsorption coupled with catalytic processes and with other separations processes (especially distillation and membrane systems) will be developed to take advantage of the unique features of each. The roles of adsorption systems will be to efficiently achieve very high degrees of purification to lower fouUng contaminant concentrations to very low levels in front of membrane and other separations processes or to provide unique separations of azeotropes, close-boiling isomers, and temperature-sensitive or reactive compounds. 

N. S. Cohen and D. A. Flanigan, Effects of Propellants Formulation on Bum Rate—Temperature Sensitivity, CPIA Pubhcation 390, Vol. 3, CPIA, Johns Hopkins University, Laurel, Md., 1984. 

A modification of the conventional soy protein isolate process has been investigated on a small pilot-plant scale. It is based on the absorption of water from the aqueous protein after extraction at pH 8.5 using temperature-sensitive polyisopyropylacrylamide gels, followed by spray drying to give a 96% protein isolate (111). 

AlGaAs quantum well infrared photodetector (QWIP) focal planes have achieved sufficient sensitivity out to 10-p.m wavelength to result in scene temperature sensitivity of ca 0.2°C when the focal plane is cooled to 77 K. Spectral sensitivity is shown in Eigure 9c and array information is given in Table 1. The supedattice, a newer tool for achieving controlled activation energy, should present many alternative infrared detection techniques. 

Iron Browns. Iron browns are often prepared by blending red, yellow, and black synthetic iron oxides to the desired shade. The most effective mixing can be achieved by blending iron oxide pastes, rather than dry powders. After mixing, the paste has to be dried at temperatures around 100°C, as higher temperatures might result in the decomposition of the temperature-sensitive iron yellows and blacks. Iron browns can also be prepared directiy by heating hydrated ferric oxides in the presence of phosphoric acid, or alkaU phosphates, under atmospheric or increased pressure. The products of precipitation processes, ie, the yellows, blacks, and browns, can also be calcined to reds and browns. 

This catalyst system is temperature-sensitive and does not function effectively at temperatures below 10°C but at temperatures over 35°C the generation of free radicals can be too prolific, giving rise to incomplete cross-linking formation. Redox systems are preferred for fabrication at temperatures ranging from 20—30°C (Fig. 5). 

Shipment Methods and Packaging. Pyridine (1) and pyridine compounds can be shipped in bulk containers such as tank cars, rail cars, and super-sacks, or in smaller containers like fiber or steel dmms. The appropriate U.S. Department of Transportation (DOT) requirements for labeling are given in Table 4. Certain temperature-sensitive pyridines, such as 2-vinylpyridine (23) and 4-vinylpyridine are shipped cold (<—10°C) to inhibit polymerisation. Piperidine (18) and certain piperidine salts are regulated within the United States by the Dmg Enforcement Agency (DEA) (77). Pyridines subject to facile oxidation, like those containing aldehyde and carbinol functionaUty, can be shipped under an inert atmosphere. 

Consider high vacuum distillation when material is temperature-sensitive at normal pressure ranges. 

Consider when solvent cannot be removed by evaporation (either temperature sensitivity or low solvent volatihty). 

Among nonmetallic resistance thermometers, an important class is that of thermistors, or temperature-sensitive semiconductkig ceramics (5). The variety of available sizes, shapes, and performance characteristics is very large. One manufacturer Hsts ki the catalog a choice of characteristics ranging from 100 Q at 25°C to 1 M Q at 25°C. 

Cold-junction compensation can be provided by a network which includes a constant voltage source and a temperature-sensitive bridge to provide an offset voltage which is proportional to the temperature sensitivity of the thermocouple and of opposite sign. 

In general, textile materials are moisture- and temperature-sensitive. As a result, all tests should be performed at ambient conditions of 21°C and 65% relative humidity unless otherwise stated. Most of the testing procedures discussed for textile materials are available in the Hterature (1,2). 

Mutation. For industrial appHcations, mutations are induced by x-rays, uv irradiation or chemicals (iiitrosoguanidine, EMS, MMS, etc). Mutant selections based on amino acid or nucleotide base analogue resistance or treatment with Nystatin or 2-deoxyglucose to select auxotrophs or temperature-sensitive mutations are easily carried out. Examples of useful mutants are strains of Candida membranefaciens, which produce L-threonine Hansenu/a anomala, which produces tryptophan or strains of Candida lipolytica that produce citric acid. An auxotrophic mutant of S. cerevisiae that requires leucine for growth has been produced for use in wine fermentations (see also Wine). This yeast produces only minimal quantities of isoamyl alcohol, a fusel oil fraction derived from leucine by the Ehrlich reaction (10,11). A mutant strain of bakers yeast with cold-sensitive metaboHsm shows increased stabiUty and has been marketed in Japan for use in doughs stored in the refrigerator (12). 

In addition, the combination coating renders the nutrient release much less temperature sensitive than most polymer-coated fertilizers. 

H2O/100 kg of adsorbent. At equilibrium and at a given adsorbed water content, the dew point that can be obtained in the treated fluid is a function only of the adsorbent temperature. The slopes of the isosteres indicate that the capacity of molecular sieves is less temperature sensitive than that of siUca gel or activated alumina. In another type of isostere plot, the natural logarithm of the vapor pressure of water in equiUbrium with the desiccant is plotted against the reciprocal of absolute temperature. The slopes of these isosteres are proportional to the isosteric heats of adsorption of water on the desiccant (see... 

Screw conveyor and mdii ect rotaiy. Indirect type, continuous operation Applicable with dry-product recirculation Appbcable with dry-product recirculation Generally requires recirculation of dry product. Little dusting occurs Chief advantage is low dust loss. Web suited to most materials and capacities, particularly those requiring drying at steam temperature Low dust loss. Material must not stick or be temperature-sensitive Not applicable Not appbcable Not appbcable... 

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