279 research outputs found
Resisting the Trauma Story: Ethical Concerns in the Oral History Archive
Get PDFThis short article presents an oral history project undertaken with refugees resettled in Southwest Virginia. From this project has emerged an understanding of refugees as curators of a personal archive of stories. A birth-to-present oral history approach can resist the reductive trauma narratives refugees are often expected to tell, yet oral historians and archivists must also be aware of the story told by the archive framework itself. The authors explore the ethical challenges of amplifying oral histories from refugees in a way that inspires action without centering the trauma story, and leave readers with questions for reflection
Fundamentals of rotating fluidized beds and application to particle separation
Get PDFRotating fluidized beds provide unique opportunities to exploit fluidization under higher particle forces. The centripetal force in a rotating bed is typically on the order of 10 times the force of gravity. Since the force keeping the particles in the unit is larger, the drag force can also be larger, allowing for higher gas velocities. This operating regime provides opportunities for higher mass transfer, heat transfer, gas throughput, and bubble suppression.
One application for using a rotating fluidized bed in in Chemical Looping Combustion (CLC). When solid fuels are used, oxygen carrier and ash are mixed in the process. In order to maintain high carbon capture efficiencies and recyclability of the oxygen carrier, the ash needs to be separated from the oxygen carrier. This separation can be done aerodynamically since the oxygen carrier is larger and heavier then the ash. It is theorized that rotating fluidized beds could improve the separation process efficiency and throughput as compared to conventional fluidized beds.
A 43cm diameter, 2.5cm thick rotating fluidized bed has been designed and constructed to investigate the application of the rotating fluidized beds to particle separation. A series of experiments have been performed to investigate the separation of glass beads (coal ash analog) from a typical chemical looping oxygen carrier. These experiments demonstrate the use of a rotating fluidized bed for particle separation as well as investigate the operational parameters that influence the efficiency of separation
Numerical simulation of the influence of the orifice aperture on the flow around a teeth-shaped obstacle
Get PDFThe sound generated during the production of the sibilant [s] results from the impact of a turbulent jet on the incisors. Several geometric characteristics of the oral tract can affect the properties of the flow-induced noise so that the characterization of the influence of different geometric parameters on the acoustic sources properties allows determining control factors of the noise production. In this study, a simplified vocal tract/teeth geometric model is used to numerically investigate the flow around a teeth-shaped obstacle placed in a channel and to analyze the influence of the aperture at the teeth on the spectral properties of the fluctuating pressure force exerted on the surface of the obstacle, which is at the origin of the dipole sound source. The results obtained for Re = 4000 suggest that the aperture of the constriction formed by the teeth modifies the characteristics of the turbulent jet downstream of the teeth. Thus, the variations of the flow due to the modification of the constriction aperture lead to variations of the spectral properties of the sound source even if the levels predicted are lower than during the production of real sibilant fricative
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Oil Shale Development from the Perspective of NETL's Unconventional Oil Resource Repository
Get PDFThe history of oil shale development was examined by gathering relevant research literature for an Unconventional Oil Resource Repository. This repository contains over 17,000 entries from over 1,000 different sources. The development of oil shale has been hindered by a number of factors. These technical, political, and economic factors have brought about R&D boom-bust cycles. It is not surprising that these cycles are strongly correlated to market crude oil prices. However, it may be possible to influence some of the other factors through a sustained, yet measured, approach to R&D in both the public and private sectors
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