2 resultados para Unconventional Superconductivity

em DRUM (Digital Repository at the University of Maryland)


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The first section of this unfinished novel, titled Silk Butterflies is a diptych about a woman named Sarah, and her desire to acquire ancestral truth regarding her identity to negate the pain she feels from losing her unborn child. Her story, told in a guarded, first person point-of-view is paralleled with Ling’s story, an unconventional, ninety-two year old Shanghainese woman who, against her desires, had her feet bound in China during the early 1920’s. Ling’s story is also told from a lyrical first-person perspective that focuses especially on sensory details, and delves into the sacrifices we make to attain standards of beauty, and the loss Ling has never recovered from. As this historical fiction progresses, their stories overlap in an unexpected way, as both Sarah and Ling attempt to revitalize forgotten histories, including how Sarah’s grandparents fled to Shanghai in the 1930’s to escape Nazi persecution during World War II.

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Surface ozone is formed in the presence of NOx (NO + NO2) and volatile organic compounds (VOCs) and is hazardous to human health. A better understanding of these precursors is needed for developing effective policies to improve air quality. To evaluate the year-to-year changes in source contributions to total VOCs, Positive Matrix Factorization (PMF) was used to perform source apportionment using available hourly observations from June through August at a Photochemical Assessment Monitoring Station (PAMS) in Essex, MD for each year from 2007-2015. Results suggest that while gasoline and vehicle exhaust emissions have fallen, the contribution of natural gas sources to total VOCs has risen. To investigate this increasing natural gas influence, ethane measurements from PAMS sites in Essex, MD and Washington, D.C. were examined. Following a period of decline, daytime ethane concentrations have increased significantly after 2009. This trend appears to be linked with the rapid shale gas production in upwind, neighboring states, especially Pennsylvania and West Virginia. Back-trajectory analyses similarly show that ethane concentrations at these monitors were significantly greater if air parcels had passed through counties containing a high density of unconventional natural gas wells. In addition to VOC emissions, the compressors and engines involved with hydraulic fracturing operations also emit NOx and particulate matter (PM). The Community Multi-scale Air Quality (CMAQ) Model was used to simulate air quality for the Eastern U.S. in 2020, including emissions from shale gas operations in the Appalachian Basin. Predicted concentrations of ozone and PM show the largest decreases when these natural gas resources are hypothetically used to convert coal-fired power plants, despite the increased emissions from hydraulic fracturing operations expanded into all possible shale regions in the Appalachian Basin. While not as clean as burning natural gas, emissions of NOx from coal-fired power plants can be reduced by utilizing post-combustion controls. However, even though capital investment has already been made, these controls are not always operated at optimal rates. CMAQ simulations for the Eastern U.S. in 2018 show ozone concentrations decrease by ~5 ppb when controls on coal-fired power plants limit NOx emissions to historically best rates.