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Abstract Thermal rectification is an exotic thermal transport phenomenon which allows heat to transfer in one direction but block the other. We demonstrate an unusual dual-mode solid-state thermal rectification effect using a heterogeneous “irradiated-pristine” polyethylene nanofiber junction as a nanoscale thermal diode, in which heat flow can be rectified in both directions by changing the working temperature. For the nanofiber samples measured here, we observe a maximum thermal rectification factor as large as ~50%, which only requires a small temperature bias of <10 K. The tunable nanoscale thermal diodes with large rectification and narrow temperature bias open up new possibilities for developing advanced thermal management, energy conversion and, potentially thermophononic technologies. 

Recent advancements in haptic force feedback technologies enable novel opportunities for the teaching of science and engineering by augmenting classical laboratory experiments with haptic experiences that provide deeper insight into the connections between theory and experiment. This contribution describes the development and implementation of a ‘kinesthetic teaching toolkit’ for the particular purpose of teaching mechanical properties of polymer networks. In the first part the background of ‘network mechanics’ is introduced at a level consistent with undergraduate and graduate courses on Polymer Science and Engineering that are being offered at Carnegie Mellon University. The challenges associated with the design of hands-on experiences to support the teaching of ‘mechanical properties of polymer networks’ are described to illustrate the opportunities for force-feedback technologies. In the second part, this paper describes the process of adopting low-cost force feedback joysticks for the emulation of a ‘rubber extension’ experiment. The opportunities for students to explore material property changes in response to defined microstructural changes are described. Finally, we elaborate the implementation of the device in a laboratory course on Colloids, Polymers and Surface that is being offered at the Chemical Engineering Department at Carnegie Mellon University.