Scaling a Hydraulic Motor for Minimally Invasive Medical Devices.

Aligned with the medical device industry's trend of miniaturization, academic and commercial researchers are constantly attempting to reduce device sizes. Many applications require miniature actuators (2 mm range) to perform mechanical work; however, biocompatible micromotors are not readily available. To that end, a hydraulic motor-driven cutting module that aims to combine cutting and drug delivery is presented.

Data from cryo-neutron phase change experiments with LH2 and LCH4.

Cryogenic Propellant management is a critical roadblock to enable long term space missions. Commonly used propellants (liquid hydrogen and methane) undergo constant vaporization but there is limited knowledge on the phase change rate and its implications on long term storage stability. This is, in part, due to the inability to image the liquid-vapor mixture inside opaque metallic containers at cryogenic temperatures.

Rapidly responsive smart adhesive-coated micropillars utilizing catechol-boronate complexation chemistry.

Smart adhesive hydrogels containing 10 mol% each of dopamine methacrylamide (DMA) and 3-acrylamido phenylboronic acid (APBA) were polymerized in situ onto polydimethylsiloxane (PMDS) micropillars with different aspect ratios (AR = 0.4, 1 and 2). Using Johnson-Kendall-Roberts (JKR) contact mechanics tests, the adhesive-coated pillars demonstrated strong wet adhesion at pH 3 (Wadh = 420 mJ m-2) and can be repeatedly deactivated and reactivated by changing the pH value (pH 9 and 3, respectively).

A New Experiment for Investigating Evaporation and Condensation of Cryogenic Propellants.

Passive and active technologies have been used to control propellant boil-off, but the current state of understanding of cryogenic evaporation and condensation in microgravity is insufficient for designing large cryogenic depots critical to the long-term space exploration missions. One of the key factors limiting the ability to design such systems is the uncertainty in the accommodation coefficients (evaporation and condensation), which are inputs for kinetic modeling of phase change. A novel, combined experimental and computational approach is being used to determine the accommodation coefficients for liquid hydrogen and liquid methane.