Matching Items (233)
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- All Subjects: energy
- Creators: Arizona State University
Description
Energy can be harvested from wastewater using microbial fuel cells (MFC). In order to increase power generation, MFCs can be scaled-up. The MFCs are designed with two air cathodes and two anode electrodes. The limiting electrode for power generation is the cathode and in order to maximize power, the cathodes were made out of a C-N-Fe catalyst and a polytetrafluoroethylene binder which had a higher current production at -3.2 mA/cm2 than previous carbon felt cathodes at -0.15 mA/cm2 at a potential of -0.29 V. Commercial microbial fuel cells from Aquacycl were tested for their power production while operating with simulated blackwater achieved an average of 5.67 mW per cell. The small MFC with the C-N-Fe catalyst and one cathode was able to generate 8.7 mW. Imitating the Aquacycl cells, the new MFC was a scaled-up version of the small MFC where the cathode surface area increased from 81 cm2 to 200 cm2. While the MFC was operating with simulated blackwater, the peak power produced was 14.8 mW, more than the smaller MFC, but only increasing in the scaled-up MFC by 1.7 when the surface area of the cathode increased by 2.46. Further long-term application can be done, as well as operating multiple MFCs in series to generate more power and improve the design.
ContributorsRussell, Andrea (Author) / Torres, Cesar (Thesis advisor) / Garcia Segura, Sergio (Committee member) / Fraser, Matthew (Committee member) / Arizona State University (Publisher)
Created2022
Description
This study deals with various flow field designs for anode, cathode, and coolant plates for optimizing the performance of proton exchange membrane fuel cell using H2 and air. In particular, the 3D models with various flow field patterns such as single parallel serpentine (anode), multi parallel (anode), multi-parallel serpentine (cathode), multi serpentine (cathode) have been evaluated for enhancing the fuel cell performance at 60 oC, with three different coolant flow designs (mirror serpentine, multi serpentine and parallel serpentine). Both the peak power and limiting current density are considered based on the parameters such as temperature distribution, pressure distribution, reactants/species distribution and the membrane water content on the active area (50 cm2) region. It is interesting to note that the coolant channel also has a significant effect in regulating the fuel cell performance at high current densities, in addition to reactant gas flow channels. The simulated single cell with Nafion (thickness: 18 m) demonstrates a peak power density of 0.97 W.cm-2 with single parallel serpentine (anode), multi parallel serpentine (cathode) and serpentine (coolant) and 0.91 W.cm-2 with multi parallel (anode), multi serpentine (cathode), and parallel serpentine (coolant) flow field designs. The simulated fuel cell performance is also experimentally validated with four cells at 60 oC using H2 fuel and air as the oxidant.
ContributorsAhmed, Rafiq (Author) / Mada Kannan, Arunachala (Thesis advisor) / Torres, Cesar (Committee member) / Lin, Jerry (Committee member) / Arizona State University (Publisher)
Created2023
Description
There is a lack of prior research about factors and conditions relating to the underdevelopment of infrastructure on Navajo Nation, especially from a community-centered perspective. As a Diné researcher, the intersection created via the fields of Science and Technology Studies (STS), American Indian Studies (AIS), and Diné Studies creates a means by which developmental policy and futures planning can be discussed. Through qualitative inquiry, specifically cross-case analysis, oral histories, and archival review from a Diné perspective, this work establishes the relationship between roads, energy, and Information and Communication Technologies (ICTs) in the Navajo Nation in relation to the historical underdevelopment of infrastructure on the reservation, especially from 2000 to 2020. Roads and energy infrastructures make way for ICT deployments, and together, these three infrastructures shape futures planning for the Nation, including governance decisions relating to partnerships, and internal versus external development. Relationships between infrastructural efforts, past colonial practices of the United States (U.S.), and relations between the U.S. and tribes during this era shape the development of relevant expertise within Navajo Nation entities and also impact access to and uses of significant funding opportunities available via the early 21st century American Recovery and Reinvestment Act. A Diné-centered concept of care through long-term infrastructure deployment relates tribal sovereignty and Indigenous ways of knowing to Indigenous Science and Technology Studies (STS) and suggests new directions for applied Diné studies in the field of Indigenous STS.
ContributorsGeorge, Alaina Sarah (Author) / Duarte, Marisa E (Thesis advisor) / Richter, Jennifer (Thesis advisor) / Wetmore, Jameson (Committee member) / Arizona State University (Publisher)
Created2023