Browsing by Author "Shaffer, Brett"
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Item Capillary Provision of Water and Nutrients to Plants Grown in Microgravity(2020 International Conference on Environmental Systems, 2020-07-31) Nabity, James; Pitts, Ray; Rehmeier, Jacob; Weislogel, Mark; Escobar, Christine; Shaffer, Brett; Escobar, AdamPassive provision of water and nutrients for the growth of plants in microgravity environmental systems can effectively be accomplished through the exploitation of capillary forces in various geometries, such as a network of wetted open interior corners. Provided the Concus-Finn condition is satisfied, capillary flows may be established along conduits that consist of simple interior corners (or ‘wedges’). A numerical free surface solver tool was employed to predict capillary flow of water to inform the design and construction of test articles for use in drop tower experiments. In addition, single and parallel flow path configurations were investigated with consideration for harvesting duckweed, a micro-flowering plant, in a microgravity environment. We report the effects of material, surface conditions, and interior corner half-angle on capillary performance. Titanium, glass and polymeric materials with factory, machined, and shot peened surfaces were used in experiments with deionized water and duckweed. The results guided the advanced development of micro-plant growth beds.Item Characterization of Carbon Dioxide Removal using Ionic Liquids in Novel Geometries(47th International Conference on Environmental Systems, 2017-07-16) Arquilla, Katya; Rundle, Tessa; Phillips, Daniel; Lampe, Alexander; Shaffer, Brett; Lima, Anthony; Fritz, Trevor; Denton, Jacob; Dixon, Jordan; Holquist, Jordan; Lotto, Michael; Nabity, JamesThe Cabin Atmosphere Revitalization through Ionic Liquids (CARIL) project is part of NASA's Exploration Systems and Habitation Academic Innovation Challenge program to provide enabling technologies for future long-duration space missions. Current atmosphere revitalization technologies require frequent maintenance and spare parts – these are not manageable issues for technologies used on missions travelling to Mars and beyond. As the possibility for resupply decreases with long-duration missions, regenerable technologies become increasingly important. CARIL is focused on the characterization of the removal of carbon dioxide (CO2) from the cabin atmosphere using two different absorption bed configurations: a 3-D printed capillary-driven contactor and a hollow-fiber contactor. A flat plate contactor will be used as an experimental control, and all designs will use the ionic liquid (IL) 1-butyl-3-methylimidazolium acetate. ILs were chosen due to their low vapor pressure and selectivity between CO2 and oxygen, making them a viable option for absorbing CO2 in micro-gravity. The focus of this research is to characterize the absorption of CO2 using specific contactor materials and geometries to provide a broad range of data to analyze and inform the future development of supported ionic liquid membranes.Item Effects of additive manufacturing on capillary-driven fluid flow for provision of water and nutrients to free floating plants(48th International Conference on Environmental Systems, 2018-07-08) Shaffer, Brett; Eble, Jonathan; Nabity, James; Escobar, ChristineAn autonomous environmentally controlled floating plant cultivation system needs robust water and nutrient delivery for use in microgravity. Passive fluid control in the microgravity environment can be accomplished through the exploitation of capillary forces in various geometries, such as a network of isolated interior corners. Capillary driven flow largely depends on the surface properties of the material. Due to the Concus-Finn condition, capillary flow designs using interior corners are limited to a range of contact angles and interior corner half-angles which meet this condition. Additive manufacturing – particularly through the fused deposition method – introduces a new dimension to this design space in that the surface structure of the additively manufactured system is axially dependent. The resulting anisotropy in surface properties due to the layer-by-layer deposition of material means that the contact between a fluid and a particular surface depends upon the surface's orientation with respect to the print axis. This study develops an empirically derived relationship between controllable variables in the additive manufacturing process (particularly, layer height and axial orientation) and their effects on capillary flow rates of water through given channel geometries constructed from plastic and metal materials. These rates are compared to the rate of evaporation and the uptake requirements for sustenance of duckweed, as well as those from established and validated modeling methods that simulate fluid surface interactions between the fluid and material for a diverse set of geometries in order to identify whether or not the empirical relationship is material agnostic.