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This paper assesses thermoelastic damping (TED) in circular nanoplates by incorporation of the small-scale effect into structural and thermal domains. The nonlocal elasticity theory and dual-phase-lag (DPL) heat conduction model are exploited for achieving the size-dependent coupled thermoelastic equations. By choosing time-harmonic and asymmetric form for deflection and temperature change, and solving the size-dependent thermoelastic eigenvalue problem, the damped natural frequency of circular nanoplate is extracted. On the basis of the complex frequency approach, an analytical relation, for the description of TED in circular nanoplates, is derived. For different boundary conditions and vibration modes, a comparison study is performed between the size-dependent results and those provided by classical continuum mechanics and heat conduction theories. Outcomes show a discrepancy between results acquired by the size effect on the structure and heat conduction. It is elucidated that how nonlocal and DPL characteristic parameters can represent the size-dependent phenomenon and can affect the magnitude of TED. A comprehensive parametric study is conducted to specify the influence of boundary constraints, vibration mode and the type of material on the amount of energy loss from TED. [ABSTRACT FROM AUTHOR]

Large temperature changes may cause degradation in physical and mechanical properties of rocks. This degradation can be influenced by heating-cooling procedure. In this study, it is proposed to investigate the influence of cooling method after heating to high temperature on the degradation of physical and mechanical properties of granite. For this purpose, two different cooling procedures are considered, the rapid cold water cooling and the slow step-by-step cooling. Two groups of granite samples are first heated to a desired temperature ranging from 25 °C to 900 °C, and then cooled respectively by using these two methods. The porosity and ultrasonic velocity of the thermally treated samples are measured. Uniaxial and triaxial compression tests are also performed to evaluate the elastic properties and compression strength. It is found that for both groups of samples, the thermal treatment induces the porosity increase, the wave velocity decrease and the modification of elastic modulus and compression strength. But the modification of mechanical properties is clearly influenced by the thermal treatment procedure. [ABSTRACT FROM AUTHOR]