Temperature coefficient of density

Temperature coefficient of density Specific energy of the fissure area in grinding Degree of filling... 

Vapor and liquid densities decrease with increasing temperature. Here, the following temperature coefficient of density is considered ... 

Densities of various hydrocarbon compounds have been reported at 20, 25, and 30 °C [35-39] including temperature coefficients of density at 25°C. For 1-alkenes, for example, the coefficients decrease with increasing Nq in the range from 0.001034gem-3 °C I for 1-pentene to 0.000733gcm 3 °C 1 for 1-dodecene. For hydrocarbons and various compounds containing heteroatoms, density/temperature correlations have been presented as a polynomial function of the type... 

The temperature dependence of density p(7) is expressed in an analogous manner by the temperature coefficient of density ... 

The temperature coefficient of density, p0, only acts in conjunction with gravitational acceleration, g, and must be combined with the density pg(30... 

Solid Density of High Temperature MoFe. The density of solid MoFe was obtained from weight and volume measurements at two temperatures above its transformation point. At +8°C., the density was 2.91 grams/cc., and at 0°C., the density was 2.88 grams/cc. The change from 2.91 to 2.88 grams/cc. reflects both the temperature coefficient of density and the... 

Atomic number Atomic weight Crystal structure Melting Density Thermal Electrical resistivity (at 20°C) Temperature coefficient of resistivity Specific Thermal Standard electrode potential Thermal neutron absorption cross-section. 

Metal A lomic number Atomic weight Lattice structure Density at 20°C (g/em ) Melting point (°C) Thermal conductivity at 0-l00°C (W/m°C) Specific heat at 0°C (J/kg C) Coefficient of linear expansion at 20-iOO°C X 70 Thermal neutron cross-section (barns) (10-- m ) Resistivity at 0°C (fiil em) Temperature coefficient of resistance o-ioo°c X 10 ... 

From Fig. 10.40 it will be seen that contact between the electrolyte (soil or water) and the copper-rod electrode is by porous plug. The crystals of CUSO4 maintain the copper ion activity at a constant value should the halfcell become polarised during measurements. The temperature coefficient of such a cell is extremely low, being of the order of 1 x 10" V/°C and can thus be ignored for all practical purposes. To avoid errors due to polarisation effects, it is necessary to restrict the current density on the copper rod to a... 

Laplace had previously deduced from his theory that the temperature coefficient of surface tension should stand in a constant ratio to the coefficient of expansion this is in many cases verified, and shows that the effect of temperature is largely to be referred to the change of density (Cantor, 1892). 

The methods of measuring the liquid phase properties were described previously [1], It was observed that heat was evolved during the preparation of all these mixtures. It should be mentioned that the electrical conductivities of the sulphuric acid-nitromethane mixtures were not constant, but were found to increase with time. Reliable data could therefore not be obtained. This is due to the fact that nitromethane reacts with sulphuric acid in dilute solutions, as has been recently discussed by Gillespie and Solomons [6]. All other properties of these mixtures were constant at 25° and measurements were restricted to this temperature. For the other four systems the viscosity, electrical conductivity and density were investigated at two temperatures 25° and 40°), because of the importance of the temperature coefficients of viscosity and electrical conductivity. The refractive indexes were measured only at 25°. The investigation of the liquid phase properties of the system with p-nitro toluene at these temperatures was possible only up to 50 mole % of p-nitrotoluene, i.e. until the solutions became saturated with respect to p-nitrotoluene. The refractive indexes of these solutions were not measured. 

The temperature coefficient of the reaction is still given by the Arrhenius equation. It is reasonable to assume that the velocity constant of the reaction is proportional to the radiation density. Now chemical heats of activation correspond to frequencies in the short infra-red region, and for these values of v the term ehvlkT in Planck s equation is large in comparison with unity. The expression for Uy thus reduces to... 

TABLE 3.5.1 Temperature Coefficients for Densities of Selected Compounds... 

It is clear from Equation 11.3 that resistivity should approach within 10% of the bulk value when the film thickness exceeds about four times the mean free path. The better the conductor, the smaller the mean free path. Thus, the resistivity approaches the bulk value as the film thickness reaches typical values of 100-200 nm for metallic conductors, or perhaps as much as several micrometers for semiconductors, depending on the intrinsic or doped carrier density. For sufficiently thick metallic films with K 1, the temperature coefficient of resistivity becomes positive, as bulk electron-phonon scattering becomes the primary contribution to resistivity [5]. Conduction in semiconductor films remains activation-limited, and retains a negative temperature coefficient. Figure 11.1 illustrates the dependence of resistivity on film thickness for sputtered... 

The properties of this proplnt are it remains rubberlike at -40°F and does not flow at+140°F its specific impulse is 170sec at lOOOpsi optimum expansion density l,81g/cm3 an exponent of 0.70 in the burning law burning rate 0.72 in/sec at lOOOpsi 70°F, and a restriction ratio of 182 under the same conditions. The temperature coefficient of pressure, thrust, burning time at constant restriction ratio is 0.6% per °C (Ref 1, pp 101 -02)... 

The target quantity in this process is the temperature, T, of the liquid. We will include the cylinder diameter, d, as characteristic geometric parameter in the relevance list. The physical properties are the density, p, the viscosity, p, the heat capacity, Cp, the thermal conductivity, k, and the temperature coefficients of viscosity, y0, and of density, p0- The process parameters are the experimental time, t, gravitational acceleration, g (because of the density differences on account of the temperature field) and the two characteristic temperatures ... 

In dilute aqueous solution (< 10 m) the behavior of amphiphiles, such as long-chain trimethylammonium, sulfate, and earboxylate salts, parallels that of strong electrolytes. At higher amphiphile concentrations, however, a pronounced deviation from ideal behavior occurs. A generalized diagram for such variations in physical properties as a function of the detergent concentration, C-, is given in Fig. 1. Some of the physical properties which have been found to exhibit this type of behavior are related to interfacial tension, electric conductivity, e.m.f., pH, density, specific heat, temperature coefficients of solubility. 

Pulsed research reactors, such as reactors of the Triga type, are especially designed for production and investigation of short-lived radionuclides. In these reactors the neutron flux is increased for about 10 ms to about 10 cm s by taking out the control rods (section 11.5). Due to the negative temperature coefficient of the zirconium hydride moderator, the outburst of power causes a sudden decrease of the moderator properties and shutting off of the reactor. After several minutes the effects have vanished and a new pulse can be started. The activities of radionuclides of various half-lives obtained with pulsed reactors are compared in Table 12.2 with those produced at constant neutron flux densities. The table shows that pulsed reactors are useful for production and investigation of radionuclides with half-lives < 10 s. 

Table 5.1. Coefficients a and b of the temperature dependency of density, p = a — bt, and the standard deviations of approximation of the investigated melts of the system LiF—KF—K2Nbp7...

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