We have constructed two mechanical snails, Robosnail 1 and Robosnail 2, inspired by the propulsion mechanisms of live gastropods. Each uses a different mechanical strategy to move on a thin layer of viscous fluid. Robosnail 1 uses a flexible flapping sheet to generate lubrication pressures in a viscous Newtonian fluid which in turn propels the snail. Robosnail 2 uses a compressible sliding sheet on a layer of Laponite, a non-Newtonian, finite-yield stress fluid.

We report the design and analysis of a high-power air-cooled heat exchanger capable of dissipating over 1000 W with 33 W of input electrical power and an overall thermal resistance of less than 0.05 K/W. The novelty of the design combines the blower and heat sink into an integrated compact unit (4" x 4" x 4") to maximize the heat transfer area and reduce the required airflow rates and power. The device consists of multiple impeller blades interdigitated with parallel-plate condensers of a capillary-pumped loop heat pipe. The impellers are supported on a common shaft and powered with a low-profile permanent magnet synchronous motor, while a single flat-plate evaporator is connected to the heat load.

We present a model to predict the behavior of a novel loop heat pipe with a capillary wick in the condenser. The heat pipe consists of a single evaporator and multiple vertically-stacked condensers interdigitated with radial-outflow fan blades of a blower. The resulting heat exchanger assembly maximizes heat transfer area by integrating the heat sink and blower together. As a result of the stacked design, the lowest condenser has the highest liquid pressure in the presence of gravity. The capillary pressure generated by the condenser wick is used to compensate for the difference in the liquid pressures among the condensers. This paper focuses on modeling and designing the heat pipe to form receding menisci in the condensers. The effect of the compensation chamber pressure and viscous losses on the meniscus orientation is examined. The results of the model show that an advancing meniscus is formed at lower heat inputs and a threshold heat input must be exceeded to form a receding meniscus. Guidelines for selecting appropriate wicks for the evaporator and condenser are reported.