The paper by Ron Lifshitz and M. L. Roukes evaluates the importance of thermoelastic damping as a fundamental dissipation mechanism in small-scale mechanical resonators, particularly in MEMS and NEMS. Thermoelastic damping occurs when acoustic modes interact with thermal phonons, leading to energy dissipation. The authors derive an exact expression for thermoelastic damping in thin rectangular beams and compare it with Zener's well-known approximation. They find that the peak damping value is independent of the beam's geometry and depends only on the material's thermodynamic properties. The exact expression shows that the damping is peaked at a specific frequency, which is influenced by the beam's dimensions. This peak damping behavior is crucial for understanding the quality factors of resonators in MEMS and NEMS, especially at submicron scales. The paper also discusses the implications of thermoelastic damping for experimental designs and provides a universal plot of damping curves for typical materials used in these systems.The paper by Ron Lifshitz and M. L. Roukes evaluates the importance of thermoelastic damping as a fundamental dissipation mechanism in small-scale mechanical resonators, particularly in MEMS and NEMS. Thermoelastic damping occurs when acoustic modes interact with thermal phonons, leading to energy dissipation. The authors derive an exact expression for thermoelastic damping in thin rectangular beams and compare it with Zener's well-known approximation. They find that the peak damping value is independent of the beam's geometry and depends only on the material's thermodynamic properties. The exact expression shows that the damping is peaked at a specific frequency, which is influenced by the beam's dimensions. This peak damping behavior is crucial for understanding the quality factors of resonators in MEMS and NEMS, especially at submicron scales. The paper also discusses the implications of thermoelastic damping for experimental designs and provides a universal plot of damping curves for typical materials used in these systems.