High efficiency heat exchangers, such as intercoolers and recuperators, are composed of complex and compact structures to enhance heat transfer. This limits the installation of conventional temperature sensors to measure the temperature inside the heat exchanger without flow disturbance. To overcome this limitation, we have developed a direct patterning method in which metal is sputtered onto a curved surface using film photoresist and the fabrication of thin film Au resistance temperature detection (RTD) temperature sensors. A photosensitive film resist has been used to overcome the difficulty of 3-dimensional photolithography on a curved surface. The film resist after 2-dimensional photolithography is laminated over an alumina rod which is deposited with Au as an RTD sensing material. The Au metal is etched chemically, and the film resist is removed to form the thin film Au-RTD temperature sensors. They are calibrated by measuring the resistance change against temperature in a thermally controlled furnace. The second order polynomial fit shows good agreement with the measured temperatures with a standard deviation of 0.02 for the temperature range of 20-450 • C. Finally, the performance of the Au-RTD temperature sensors was evaluated.
This study demonstrates the forming process of a semi-solid material with a solid fraction of about 45 per cent after the primary α-Al particle in the semi-solid material is globularized during solidification by electromagnetically stirring the molten metal poured out into the sleeve. By rheological forming experiments incorporating electromagnetic stirring (EMS) using Al6061 alloy, the process parameters are optimized to be of 0.3 m/s of forming velocity, 45 MPa of forming pressure, 10 s of stirring time, and 30 A of stirring current to get the best quality. The product exhibited the highest tensile strength of 312.8 MPa and elongation of 4.51 per cent at positions where the pressure was directly applied to the material and overlapping occurred.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.