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[Display omitted] Phase change materials (PCM) are largely assessed on their ability towards energy storage and their enthalpy efficiency of discharging the stored energy. Nevertheless, their applications are limited by the low thermal conductivity behaviour, despite their tunable transition temperature abilities. The present work demonstrates a novel concept to develop and explore PCM composite by embedding two unique zinc oxide tetrapod classes to engineer the heat transfer mechanism for potential utilization in thermal energy storage. Tetrapods embedded phase change material (TPCM) composite displayed up to 94% enhancement in thermal conductivity without compromising melting enthalpy. TPCM composite with high thermal conductivity, high heat capacity, broad photo-absorptivity, improved stability in isothermal conditions, and long thermal cycles offer attractive solutions for effective thermal energy storage, efficient solar energy harnessing, and thermal management. With demonstrated abilities, the developed TPCM composite material could play a significant role in the progress of renewable energy needs in future. [ABSTRACT FROM AUTHOR]

The natural ocean/river currents energy can be harvested using Flow Induced Motion (FIM) phenomena. The effect of damping-ratio and mass-ratio on Flow Induced Motion energy harnessing of a square cylinder are numerically investigated for Reynolds number 15500 < Re < 232000 (0.2 m/s < flow velocity <3.0 m/s). Four typical regions can be observed in the Flow Induced Motion responses, including Vortex Induced Vibration (VIV) Initial Branch, Vortex Induced Vibration Upper Branch, Vortex Induced Vibration-Galloping Transition and Galloping. Results indicate that as the velocity increases, the number of vortices shed per cycle increases, and the harnessed power increases without upper limit. The energy conversion efficiency increases up to the highest value until the Vortex Induced Vibration upper branch. Then, it starts decreasing and tends to a relatively small value in the galloping region. Increasing mass-ratio will shorten the velocity range of Vortex Induced Vibration. High damping-ratio has a negative impact on oscillation amplitude, but provides a boost for energy harnessing. In all tests, the power (143 W) is considerable at damping-ratio = 0.6. As the damping-ratio reaches up to 0.8 (nearing critical damping), galloping will no longer occur. [ABSTRACT FROM AUTHOR]

Abstract: Maximization of the harvested energy from piezoelectric bimorphs has been the objective of many researchers in the past few years. Most of the previous work focused on bimorphs covered with a single pair of electrodes, leading to a great loss of generated power due to charge cancellation from areas with opposite strains. In this paper, we assume the bimorph is covered with multiple pairs of electrodes to overcome the problem of charge cancellation. We focus on circular bimorphs subject to base excitation at different frequencies. We also assume that the capacitances attached to the electrodes are controllable and can be optimized to maximize the power output at a given excitation frequency. Moreover, we change the topology of the bimorph by making its thickness vary with the radius of the bimorph. Numerical examples show that the harnessed power can be maximized by increasing the capacitance of anti-nodal elements while decreasing that of nodal elements. Also, decreasing the thickness of piezoelectric layers at anti-nodal elements allows more straining and hence the generation of more power. It is shown that the compatibility of the topology of the piezoelectric bimorph with the shape of the second axisymmetric mode yields more power compared with its compatibility with the first mode. [Copyright &y& Elsevier]