Preface -- 1 General Introduction to Near-Critical and Supercritical Fluids -- I Thermomechanical Effects -- 1 Bridging Gas and Near-Critical Fluid Dynamics -- 2 Bridging Gas and Near-Critical Fluid Dynamics -- 3 Temperature and Density Equilibration -- 4 Heat Transfer -- II Heat Transfer Experiments Performed in Weightless Conditions -- 5 Quick Overview of Some Test Cells -- 6 The Pancake Test Cell -- 7 Heat Transport by the Piston Effect: Experiments -- 8 Coexisting Liquid-Vapor Phases -- III Effects of a Steady-State Acceleration Field -- 9 Interaction Between the Piston Effect and Gravitational Convection -- 10 Rayleigh-B´enard and Rayleigh-Taylor Instabilities -- 11 Experiments in a weak acceleration field and on Earth -- IV Influence of Time-Dependent Acceleration Fields -- 12 Response to Low-Frequency Vibrations: Solid-Like Behavior -- 13 Thermovibrational Effect -- V Appendices.