Liquid expansion coefficient

The liquid expansion coefficient, a, for the thermal expansion coefficient, a-p... 

DISPERSION FORCES AND SURFACE TENSION OF ORGANIC LIQUIDS. EXPANSION COEFFICIENT. 

A recent investigation gives some insights into one aspect of the kinetics of cluster formation, both above and below Tg. In a study of the expansion coefficients of the styrene ionomers as a function of ion contentit was.found that the equilibrium values were independent of ion content. However, whenever the sample had been allowed to remain at room temperature for a few hours after cooling from above Tg, and subsequently heated again above the glass transition temperature, the first run yielded a value of the liquid expansion coefficient ca 25% lower than that... 

The viscosity of liquid silicates such as drose containing barium oxide and silica show a rapid fall between pure silica and 20 mole per cent of metal oxide of nearly an order of magnitude at 2000 K, followed by a slower decrease as more metal oxide is added. The viscosity then decreases by a factor of two between 20 and 40 mole per cent. The activation energy for viscous flow decreases from 560 kJ in pure silica to 160-180kJmol as the network is broken up by metal oxide addition. The introduction of CaFa into a silicate melt reduces the viscosity markedly, typically by about a factor of drree. There is a rapid increase in the thermal expansivity coefficient as the network is dispersed, from practically zero in solid silica to around 40 cm moP in a typical soda-lime glass. 

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,... 

B = cubical expansion coefficient per degree F for the liquid at the expected temperature. For values see specific liquid data or see table below for typical values. 

It is clear that nonconfigurational factors are of great importance in the formation of solid and liquid metal solutions. Leaving aside the problem of magnetic contributions, the vibrational contributions are not understood in such a way that they may be embodied in a statistical treatment of metallic solutions. It would be helpful to have measurements both of ACP and A a. (where a is the thermal expansion coefficient) for the solution process as a function of temperature in order to have an idea of the relative importance of changes in the harmonic and the anharmonic terms in the potential energy of the lattice. 

B = cubical expansion coefficient per °F of liquid at expected temperature (see tabulation in text)... 

Smith, W. T., Greenbaum, S. and Rutledge, G. P. (1954) J. Phys. Chem. 58, 443. Correlation of critical temperature with thermal expansion coefficients of organic liquids. 

Au is the difference between the liquid and glassy volumetric expansion coefficients and the temperatures are in kelvin. "The WLF equation holds between I], or / f 10 K and abftut 100 K above 7A,. Above this temperature, for thermally stable polymers, Berry and Fox (28) have shown that a useful extension of the WLF equation is the addition of an Arrhenius term with a low activation energy. 

The expansion coefficient fi for water at 32°F should be used. This is estimated using liquid volumetric data from the steam tables over a short range of temperatures around 32°F. However, the steam tables do not provide liquid water specific volume data below 32°F. A value between 32°F and some appropriate higher temperature will suffice. From the steam tables ... 

Consider Problem 9-9, part a. This time use alcohol as a liquid medium with a thermal expansion coefficient of 1.12 X 10 3/°C. The heat capacity of the alcohol is 0.58 kcal/kg °C, and its density is 791 kg/m3. Determine the relief size required. 

Results for thermal expansion coefficient of liquids are presented for major organic chemicals. The results are especially helpful in the design of relief systems for process equipment containing liquids that are subject to thermal expansion. 

Physical and thermodynamic property data, such as thermal expansion coeffici t, are important in process engineering. The following brief discussion illustrates such importance. Liquids contained in process equipment will expand with an increase in temperature. To accommodate such expansion, it is necessary to design a relief system which will relieve (or vent) the thermally expanding liquid and prevent pressure build-up from the expansion. If provisions are not made for a relief system, the pressure will increase from die diermally expanding liquid. If the pressure increase is excessive, damage to the process equipment vtdll occur. 

The following equation was selected for correlation of thermal expansion coefficient of liquid as a function of temperature ... 

The results for thermal expansion coefficient are given in Table 7-1 for major organic chemicals. The presented values are applicable to a wide variety of substances. The tabulation also discloses the temperature range for which the equation is useable. The respective minimum and maximum temperatures are denoted by TMIN and TMAX. Spot values are provided at 25 C for both thermal expansion coefficient and liquid density. 

A comparison of calculated and actual data values for thermal expansion coefficient of liquid in Figure 7-2 for a representative compound. The graph indicates good agreement of calculated and data values. 

The correlation results maybe used for calculation of thermal expansion coefficient of liquid and volumetric flow from thermal expansion. Examples are shown in Table 7-2. 

Estimate the thermal expansion coefficient of liquid for n-pentane (CSH12) at 40 C. 

Finally, it behaves like a liquid provided the chain length is not too long. Just around T some physical properties change distinctively such as the specific volume, the expansion coefficient, the specific heat, the elastic modulus, and the dielectric constant. Determination of the temperature dependence of these quantities can thus be used to determine Tg. 

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