Browsing by Author "Umashankar, Viverjita"
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- Local Reuse of Furniture Enabled by User-to-User Online PlatformsUmashankar, Viverjita (Virginia Tech, 2022-06-23)Discarded furniture constitutes a significant share of bulky waste directed to landfills and incinerators each year in the USA. This has implications for resource consumption, social equity, and other sustainability concerns. Reuse of furniture provides a strategy for waste prevention and enables product life extension and offset of new consumption as part of a circular economy (CE). Using online platforms (e.g., Facebook, Craigslist), users can connect directly to acquire and/or discard used furniture items that would otherwise be disposed. Much of the existing literature focuses on an individual's motivations for disposing/acquiring used products, and not on the mechanics and/or practice of reuse. This study explores reuse practices, perspectives, and individual engagement in the local reuse of furniture through user-to-user (U2U) online platforms using two data sources and methodologies. To understand the characteristics of used furniture available for local reuse via U2U online platforms, web-scraping was conducted on Craigslist posts over a four-month period to collect data regarding furniture type, condition, and location. In parallel, individuals were invited to complete a questionnaire regarding their use of U2U online platforms for acquiring/disposing of used furniture, perceived convenience of using online platforms, and the extent to which reuse transactions were 'local'. This study found that the product type, perceived convenience, and access to information played key roles in the local reuse of furniture. This study has important implications for sustainable consumption systems in a local circular economy.
- Nature-inspired systems exploiting porous media for multiphase flowsUmashankar, Viverjita (Virginia Tech, 2020-05-06)This thesis studies multi-phase flows within two different types of porous nature-inspired material systems: multi-layered feathers and synthetic trees. (1) How multilayered feathers enhance underwater superhydrophobicity. Inspired by ducks, here we demonstrate that air pockets can withstand up to five times more hydrostatic pressure when using stacked layers of synthetic feathers instead of a single layer. The mechanism for the multi-layered enhancement is the more tortuous pathway required for water impalement, which serves to pressurize the air pockets enclosed in the pores. We study this air compression effect using a probabilistic model, in which we quantify the tortuous pathway in stacked feather layers in terms of filled volume fraction of the pores. Our findings suggest that multi-layered coatings could enable robust underwater superhydrophobicity. (2) Oil-Water separation using synthetic trees. In the world's tallest trees, water evaporating from leaves generates enough suction to lift water over 100 m high. Transpiration can similarly be attained in synthetic trees by coupling nanoporous leaves" with conduits mimicking xylem capillaries. Here, we demonstrate that by adding filters to the free ends of the xylem conduits, the hydraulic load generated by transpiration can be used for oil-water separation. The working principle is illustrated using the pressure balance equation for the synthetic tree.