Abstract: Various micro-transducers incorporating piezoelectric materials for converting energy in one form to useful energy in another form are disclosed. In one embodiment, a piezoelectric micro-transducer can be operated either as a micro-heat engine, converting thermal energy into electrical energy, or as a micro-heat pump, consuming electrical energy to transfer thermal energy from a low-temperature heat source to a high-temperature heat sink. In another embodiment, a piezoelectric micro-transducer is used to convert the kinetic energy of an oscillating or vibrating body on which the micro-transducer is placed into useful electrical energy. A piezoelectric micro-transducer also is used to extract work from a pressurized stream of fluid. Also disclosed are a micro-internal combustion engine and a micro-heat engine based on the Rankine cycle in which a single fluid serves as a working fluid and a fuel.

Abstract: A method for the production of fine-grain tungsten carbide (WC) powder comprising heating a tungsten precursor compound in contact with a gas mixture including a hydrocarbon such as methane (CH4). The method is preferably a one-step continuous method wherein the heating rate and reaction temperature is well controlled for the economical production of high quality tungsten carbide powder. The tungsten carbide powder advantageously has a high purity and a small crystallite size and can be used in the manufacture of products such as cutting tools having high wear resistance.