Abstract: A formed sheet heat exchanger is provided for exchanging heat between fluids is provided. The apparatus includes flow divider sheets that are positioned in a stacked configuration and extend in a longitudinal direction so that adjacent pairs of the sheets define flow passages therebetween for receiving first and second fluids. Each of the sheets is nonuniform in the longitudinal direction, having a manifold portion and a corrugated portion. The corrugated portions of each adjacent pair of sheets define a plurality of fluid channels therebetween that are connected to the portion of the flow passage defined between the manifold portions. The fluid channels are configured to receive the first or second fluids and transfer thermal energy therebetween through the flow divider sheets.

Abstract: Systems and methods are disclosed to effectively fracture dendrite arms and/or reduce grain size in a solidifying metal melt pool. Ultrasonic energy is applied to the solidifying metal in the liquid metal pool directly or via a substrate on which the metal is provided. In another embodiment, ultrasonic energy is applied over a range of frequencies and/or tuned to the resonant frequency of solidifying dendrite arms. Advantageously, the present invention prevents or hinders the growth of large columnar dendrites and instead allows for the formation of a high density of randomly oriented grains with a reduction in grain size, thereby enhancing the quality of the deposited metal and therefore improving the mechanical properties of the fabricated or repaired structure.

Abstract: A formed sheet heat exchanger is provided for exchanging heat between fluids is provided. The apparatus includes flow divider sheets that are positioned in a stacked configuration and extend in a longitudinal direction so that adjacent pairs of the sheets define flow passages therebetween for receiving first and second fluids. Each of the sheets is nonuniform in the longitudinal direction, having a manifold portion and a corrugated portion. The corrugated portions of each adjacent pair of sheets define a plurality of fluid channels therebetween that are connected to the portion of the flow passage defined between the manifold portions. The fluid channels are configured to receive the first or second fluids and transfer thermal energy therebetween through the flow divider sheets.