Coefficient of cubic thermal

The quantity equal to the coefficient of (cubical) thermal expansion a of the substance constituting the system, and — ) is the... 

Finally, when a solid having an initial overall volume V , measured at a reference temperature T , is heated to a final temperature T, it exhibits a final volume V > V. The relative increase of cross-section A V/Vj, is directly proportional to the temperature difference AT. The proportionality coefficient is called the coefficient of cubic thermal expansion and is denoted by the Greek letter or by the acronym CVTE and expressed in K . It is defined by the following equation ... 

Two basically similar methods have been developed by ASTM to measure the coefficient of linear thermal expansion (ASTM D 696) and the coefficient of cubical thermal expansion of plastics (ASTM D 864), respectively. The values reported in the trade journals are usually the coefficients of linear thermal expansion. 

H. H. Cady and W. H. Rogers, Enthalpy, Density, and Thermal Coefficient of Cubical Expansion ofiTNT, LA-2696, LLL, Livermore, Calif., 1962. 

The thermal expansion coefficients of cubic materials are isotropic and hence do not exhibit this phenomenon. 

GLASS TRANSITION TEMPERATURES AND THERMAL COEFFICIENTS OF CUBICAL EXPANSION OF POLY /DMSOPROPYLIDENEGALACTOSE ACRYLATE/ AND POLY /DI-ISOPROPYLIDENEGALACTOSE METHACRYLATE/. SEWELL J H ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH /ENGLAND/... 

Afterwards, above 2300°C, tetragonal zirconia transforms into high-temperature cubic zirconia (i.e., fluorite type) with a mass density of 5500 kg.m and a coefficient of linear thermal expansion of 10.5 x 10 K ... 

The thermal expansion of plastics can be increased by the incorporation of reinforcing agents or fillers into the formulation. Thns, the incorporation of ceramic powder filler into polytetraflnroethylene (PTFE) rednces the coefficient of thermal expansion. On the other hand, the incorporation of 20% glass fiber into epoxy resins will increase the coefficient of cubical expansion from 0.5 mn/mn/°C x 10" to 2.0 mn/mn/°C x 10. Reinforcanent of perfluoroalkoxyethylene improved the heat distortion temperature at 0.45 MPa from 24 C to lOO C and at 1.8 MPa from 30°C to 58°C. This was accompanied by a nominal increase in tensile strength. 

Refractive index (20 °C) Coefficient of cubical expansion Heat of combustion Thermal conductivity Dielectric constant Volume resistivity Dielectric strength... 

This table lists values of /3, the cubical coefficient of thermal expansion, taken from Essentials of Quantitative Analysis, by Benedetti-Pichler, and from various other sources. The value of /3 represents the relative increases in volume for a change in temperature of 1°C at temperatures in the vicinity of 25°C, and is equal to 3 a, where a is the linear coefficient of thermal expansion. Data are given for the types of glass from which volumetic apparatus is most commonly made, and also for some other materials which have been or may be used in the fabrication of apparatus employed in analytical work. 

Thermal expansion values can be calculated from measurements of thermal deflection of enamel—metal composites. The cubical thermal expansion coefficient ia the temperature range of 0—300°C can also be calculated usiag the additive formula ... 

If a volume expansion is required, then mccisurements in three simultaneous dimensions are needed, a result experimentally difficult to achieve, to say the least. Even a slab of a single crystal does not completely solve the problem since thermal expansion in three dimensions is needed for the volume thermal expansion coefficient. The crystal has three (3) crystallographic axes and may have three (3) linear coefficients of expansion. Only if the crystal is cubic does one have the case where all three values of ol are equal. 

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