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A gate driver with efficient energy recovery based on bidirectional buck/boost converter is proposed. The proposed gate‐drive circuit is constructed by power supply, energy storage module and energy converter. Instead of discharging directly in conventional gate drivers, gate charge Qg in the proposed gate driver is released to the storage capacitor during turning‐off transition of power MOSFET. Principle of the proposed gate driver is analysed, and design consideration of key parameters are also suggested. The gate‐drive losses of the proposed gate driver and resonant gate driver are, respectively, tested as 0.102 and 0.125 W at 100 kHz. The test result proves that power consumption of the proposed gate driver is significantly decreased. [ABSTRACT FROM AUTHOR]

A hallmark of living matter is its ability to extract and transform energy from the environment. Not surprisingly, biology students are required to take thermodynamics. The necessity of coupling exergonic reactions to endergonic processes is easily grasped by most undergraduate students. However, when addressing the thermodynamic concept of coupled reactions, both students and textbook authors often make claims that clash with the Second Law of Thermodynamics. Herein, I point out the most common flaws, analyze the causes leading to these mistakes, and suggest a few rules to avoid them. [ABSTRACT FROM AUTHOR]

We have been developing an electrohydraulic total artificial heart system. The system comprises an intrathoracic pumping unit composed of diaphragm type ellipsoidal blood pumps and an energy converter in addition to an electronics unit. The in vivo performance of the pumping unit was evaluated in a series of animal implantations with 3 calves weighing 62–85 kg. An interatrial shunt 4.5 mm in diameter was made in the atrial septum to compensate left-right imbalance. Two calves died early postoperatively, one of external controller power failure and the other of interatrial shunt stenosis due to thrombus formation. One calf, however, survived over 10 days under stable circulatory conditions. No abnormality was found in the oxygen metabolic condition or in major organ functions. The generation and dissipation of heat from the device was acceptable. This animal died of device malfunction caused by energy converter bearing breakdown. The device demonstrated a good anatomic fit without compromising the great vessels and adjacent tissues. It is concluded that the pumping unit has a sufficient in vivo basic performance although appropriate countermeasures are to be implemented against the detected problems concerning mechanical durability and interatrial shunt patency. [ABSTRACT FROM AUTHOR]

It is the goal of this section to publish material that provides information regarding specific issues, aspects of artificial organ application, approach, philosophy, suggestions, and/or thoughts for the future. Proposal of a New Electromechanical Total Artificial Heart: The TAH Serpentina A new type of energy converter for an electromechanical total artificial heart (TAH) based on the principle of a unidirectional moving motor is described. Named the TAH Serpentina, the concept consists of 2 major parts, a pendulum shaped movable element fixed on one side using a joint bearing and a special shaped drum cam. Pusher plates are mounted flexibly to the crossbar of the pendulum. A motor drives the special shaped drum cam linked to the pendulum through a ball bearing. The circular motion of the unidirectional moving brushless DC motor is transferred into the linear motion of the pendulum to drive the pusher plates. Using a crossbar with a variable length, the stroke of the pendulum and therefore the displaced blood volume is alterable. To achieve a variable length, an electric driven screw thread or a hydraulic system is possible. Comparable to the natural heart, cardiac output would be determined by frequency and stroke volume. [ABSTRACT FROM AUTHOR]