Temperature preference

Regardless of the temperature-measuring deviee to be used, on-site eali-bration of the entire measurement system is desirable. Usually, a two-point eheek ean be made by employing frozen and boiling water. At the very least, all deviees ean be eheeked at a eommon temperature, preferably in the midrange of expeeted temperatures so that any deviant deviees ean be disearded. This eheek is partieularly desirable for low-head maehines where the temperature rise will be slight. 

Cathodoluminescence microscopy and spectroscopy techniques are powerful tools for analyzing the spatial uniformity of stresses in mismatched heterostructures, such as GaAs/Si and GaAs/InP. The stresses in such systems are due to the difference in thermal expansion coefficients between the epitaxial layer and the substrate. The presence of stress in the epitaxial layer leads to the modification of the band structure, and thus affects its electronic properties it also can cause the migration of dislocations, which may lead to the degradation of optoelectronic devices based on such mismatched heterostructures. This application employs low-temperature (preferably liquid-helium) CL microscopy and spectroscopy in conjunction with the known behavior of the optical transitions in the presence of stress to analyze the spatial uniformity of stress in GaAs epitaxial layers. This analysis can reveal,... 

Discussion. With an acidic titanium(IV) solution hydrogen peroxide produces a yellow colour with small amounts oftitanium(up to 0.5 mg ofTiOz permL), the intensity of the colour is proportional to the amount of the element present. Comparison is usually made with standard titanium(IV) sulphate solutions a method for their preparation from potassium titanyl oxalate is described below. The hydrogen peroxide solution should be about 3 percent strength (ten volume) and the final solution should contain sulphuric acid having a concentration from about 0.75 to 1.75M in order to prevent hydrolysis to a basic sulphate and to prevent condensation to metatitanic acid. The colour intensity increases slightly with rise of temperature hence the solutions to be compared should have the same temperature, preferably 20-25 °C. 

The coefficient o, is either calculated from two densities of sufficient accuracy reported at different temperatures, preferably by the same investigator, or estimated by examination of the coefficient of expansion of similar compounds obtained from a least squares calculation. The constant term then results from equation (1.17) after eliminating values with large uncertainties... 

The other problems include finding best individual temperatures, preferred yields from complex reactions, best arrangements of reactor elements, and so on. 

A final contribution to the accuracy and precision of the melting point is the ability of the instrument operator to determine when the sample melts and at what temperature, preferably simultaneously. This contribution to the error is also related to the heating rate. 

In general, foams will be more stable when they are generated with water at ambient or lower temperature. Preferred water temperatures range from 35 to 80°F (2 to 27°C). Either fresh or seawater may be used. Water containing known foam contaminants, such as detergents, oil residues, or certain corrosion inhibitors, may adversely affect foam quality and appropriate steps should be taken to ensure an adequate supply of suitable quality water. See NFPA 11 for more information on application rates. 

In 1972, Gnpta and coworkers reported the preparation of twelve A-arylhydroxamic acids by the condensation of A-l-naphthylhydroxylamine and acid chloride in diethyl ether medium . An aqneons snspension of sodium bicarbonate was added to neutralize the liberated hydrochloric acid. The formation of a diacylated derivative was practically prevented by carrying ont the reaction at low temperature, preferably below 0 °C. 

The most serious competing reaction involved in the conversion of nitriles to imino ester hydrochloride is the decomposition of the latter to an amide and an alkyl chloride [28]. This decomposition can be avoided or minimized by using low reaction temperatures (preferably below about 60°C). The decomposition is favored in highly polar solvents [28]. 

Catalytic combustion for gas turbines has received much attention in recent years in view of its unique capability of simultaneous control of NOX) CO, and unbumed hydrocarbon emissions.1 One of the major challenges to be faced in the development of industrial devices is associated with the severe requirements on catalytic materials posed by extreme operating conditions of gas turbine combustors. The catalytic combustor has to ignite the mixture of fuel (typically natural gas) and air at low temperature, preferably at the compressor outlet temperature (about 350 °C), guarantee complete combustion in few milliseconds, and withstand strong thermal stresses arising from long-term operation at temperatures above 1000°C and rapid temperature transients. 

All aromatic aldehydes and heterocyclic aldehydes substituted with strong electron-withdrawing groups react cleanly with sulfur tetrafluoride at elevated temperatures, preferably in the presence of hydrogen fluoride, to give good yields of the respective difluoromethyl derivatives typical examples are given by the formation of 15. 

Boil 1 L of water for 5 min to expel C02. Pour the water into a polyethylene bottle, which should be tightly capped whenever possible. Calculate the volume of 50 wt% NaOH needed (—5.3 mL) to produce I L of —0.1 M NaOH. Use a graduated cylinder to transfer this much NaOH to the bottle of water. Mix well and allow the solution to cool to room temperature (preferably overnight). 

Temperature influences the rates of chemical reactions. In theory, the range of temperatures tolerated by life forms is comparatively wide, but, in fact, each species shows characteristic, limited temperature preferences and tolerances. 

Temperature is therefore a determining factor influencing the timing and character of both somatic and generative production in Black Sea fish. All the species examined form a series, which is related to their temperature preference anchovy - horse-mackerel - red mullet - pickerel - whiting - sprat. In the first species the somatic and generative productions coincide, while in the last there is a large space of time between them. In horse-mackerel, red mullet and pickerel there is a partial overlap. 

It appears that the level of food consumption also varies in other species during the course of a year and differs according to the temperature preferences of the fish. As an example, during the intensive feeding period of summer, the... 

As noted in Chapter 2, Emeretli (1994a) described the temperature kinetics of LDH and SDH in three fish with different temperature preferences, illustrating the actual rate of enzymatic reactions occurring in these fish over the whole annual cycle (Figure 1, page 11). Such data correspond far more appropriately to the ecology of the fish than those routinely obtained at 2S°C. 

In the Black Sea, the production of protein and accumulation of lipid occur simultaneously in cold-water fish, while in the warm-water fish the activities are separated. Pickerel, which are intermediate as regards temperature preference, display similarities to both other forms. Like the warm-water fish, the major part of production occurs during the warm season, although the amplitude of the biological rhythms is not as pronounced. Like the cold-water whiting, the pickerel use protein, not lipid, as a main reserve. 

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