Temperature on strength

Fig. 9. Effect of temperature on strength and ductiUty of a nickel-base superaHoy, IN-939, showing A, tensile strength B, 0.2% proof stress C, reduction in...

The mechanical properties of wood tend to increase when it is cooled and to decrease when it is heated (6,18). If untreated wood heated in air is not exposed to temperatures of more than - 70° C for more than about 1 year, the decrease in properties with increasing temperature is referred to as immediate or reversible ie, the property would be lower if tested at the higher temperature but would be unchanged if heated and then tested at room temperature. The immediate effect of temperature on strength and modulus of elasticity of clear wood, based on several different loading modes, is illustrated in Figures 4—6 (6). 

Fig. 5. The immediate effect of temperature on strength properties of clear wood, expressed as percentage of value at 20°C. Trends illustrated are composites from studies on three strength properties modulus of mpture in bending, tensile strength perpendicular to grain, and compressive strength parallel to grain. VariabiUty in reported results is illustrated by the width of the bands. MC = moisture content.

Table 3.36. Effect of Elevated Temperatures on Strength of Titanium and Alloys [35]...

Influence of reactant mole ratio at different reaction temperature on strength of acetic acid and acetaldehyde is explained in Table 5. The strength of acetic acid is more (9.2% and 15.6%) at lower 02/Ethanol molar ratio when compared at equivalent operating temperatures (e.g., 175°C and 200°C with 02/Ethanol molar ratio of 4.9). (The corresponding values of acetic acid are 5.9% and 8% at 02/Ethanol molar ratio of 8.51.) However, for higher acetaldehyde yield, the lower temperature (175°C) and lower 02/Ethanol molar ratio (4.9) are preferred. This also contributes to maximum total selectivity (85.7%). The rise of AT with low 02/Ethanol molar ratio is as expected (Fig.l). 

Influence of reactant mole ratio at different reaction temperature on strength of acetic acid ... 

Effect of Temperature on Strength. Work by Rennie et al. indicates that the flexural strength of IVz in. X 1% in. X 10 in. sulfur prisms depends markedly on the temperature at which they are equilibrated before testing (2). Other investigators (3) have noted that sulfur specimens having a substantial volume/surface area ratio may undergo thermal shock, a durability problem in which a fluctuating temperature may... 

Fig. 14. Comparison of theoretical predictions by Termonia and Smith (1986) with experimental results by Schaefgen et al. (1979). (a) Effect of temperature on strength of Kevlar, (b) Time to break for Kevlar and...

Figure 5.6. Effect of temperature on strength and modulus of molded graphite.

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