7,770 research outputs found
Alien Registration- Hughes, John J. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/21421/thumbnail.jp
Which Triggers Produce the Most Erosive, Frequent, and Longest Runout Turbidity Currents on Deltas?
Subaerial rivers and turbidity currents are the two most voluminous sediment transport processes on our planet, and it is important to understand how they are linked offshore from river mouths. Previously, it was thought that slope failures or direct plunging of river floodwater (hyperpycnal flow) dominated the triggering of turbidity currents on delta fronts. Here we reanalyze the most detailed timeālapse monitoring yet of a submerged delta; comprising 93 surveys of the Squamish Delta in British Columbia, Canada. We show that most turbidity currents are triggered by settling of sediment from dilute surface river plumes, rather than landslides or hyperpycnal flows. Turbidity currents triggered by settling plumes occur frequently, run out as far as landslideātriggered events, and cause the greatest changes to delta and lobe morphology. For the first time, we show that settling from surface plumes can dominate the triggering of hazardous submarine flows and offshore sediment fluxes
Pressurised calcination-atmospheric carbonation of limestone for cyclic CO2 capture from flue gases
A study was carried out to investigate the CO2 capture performance of limestone under atmospheric carbonations following pressurised calcination. A series of tests was carried out to study the role of pressurised calcination using a fluidised bed reactor. In this investigation, calcination of limestone particles was carried out at three levels of pressure: 0.1 MPa, 0.5 MPa, and 1.0 MPa. After calcination, the capture performance of the calcined sorbent was tested at atmospheric pressure. As expected, the results indicate that the carbonation conversion of calcined sorbent decreases as the pressure is increased during calcination. Pressurised calcination requires higher temperatures and causes an increase in sorbent sintering, albeit that it would have the advantage of reducing equipment size as well as the compression energy necessary for CO2transport and storage, and an analysis has been provided to give an assessment of the potential benefits associated with such an option using process software.EPSR
Pleistocene occupation of the arid zone in Southeast Australia: Research prospects for the Cooper Creek-Strzelecki Desert Region
Archaeological evidence for the presence of people in southeastern Australia as early as 40,000 years ago in environments substantially different from the Southeast Asian homeland of the initial colonists of Greater Australia has generated much discussion on when and how this remarkable feat of colonisation took place, and what was the nature and pace of adjustment of the early colonists to this new continent (see for example Bowdler 1976; Jones 1979; White and O'Connell 1979). Tied in with this discussion are questions of whether there was one group of colonists or several (see Thorne 1971, 1977), and to what extent they transformed the landscape through their impact on the fauna, flora and landforming processes
Pleistocene Archaeology in the Flinders Range: Research Prospects
This research in the Flinders Range is aimed at extending northward the earlier work by Lampert (1977, 1979, forthcoming), that was directed mainly towards the prehistory of Kangaroo Island and adjacent parts of the South Australian mainland. In that region the early stone industry is known as the Kartan. Presumably Pleistocene in origin, it is characterized by a predominance of heavy core tools, while steep-edged scrapers made on flakes constitute a relatively minor element compared with early industries found elsewhere in Australia. Because of this difference, the Kartan is seen by Lampert as a regional variant of the Australian core tool and scraper tradition. Claims by Cooper (1943) for the presence of the Kartan industry at widespread sites in the Flinders Range prompted our investigation of the region
Image analysis of the AXAF VETA-I x ray mirror
Initial core scan data of the VETA-I x-ray mirror proved disappointing, showing considerable unpredicted image structure and poor measured FWHM. 2-D core scans were performed, providing important insight into the nature of the distortion. Image deconvolutions using a ray traced model PSF was performed successfully to reinforce our conclusion regarding the origin of the astigmatism. A mechanical correction was made to the optical structure, and the mirror was tested successfully (FWHM 0.22 arcsec) as a result
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