2,288 research outputs found
Flaw growth behavior of Inconel 718 at room and cryogenic temperature Final report, 29 Apr. 1968 - 31 Oct. 1969
Fracture crack propagation in Inconel at room and cryogenic temperatures for surface defective sample
Meltwater Intrusions Reveal Mechanisms for Rapid Submarine Melt at a Tidewater Glacier
Submarine melting has been implicated as a driver of glacier retreat and sea level rise, but to date melting has been difficult to observe and quantify. As a result, melt rates have been estimated from parameterizations that are largely unconstrained by observations, particularly at the near-vertical termini of tidewater glaciers. With standard coefficients, these melt parameterizations predict that ambient
melting (the melt away from subglacial discharge outlets) is negligible compared to discharge-driven melting for typical tidewater glaciers. Here, we present new data from LeConte Glacier, Alaska, that challenges this paradigm. Using autonomous kayaks, we observe ambient meltwater intrusions that are ubiquitous within 400 m of the terminus, and we provide the first characterization of their properties, structure, and distribution. Our results suggest that ambient melt rates are substantially higher (×100) than standard theory predicts and that ambient melting is a significant part of the total submarine melt flux. We explore modifications to the prevalent melt parameterization to provide a path forward for improved modeling of ocean-glacier interactions.This work was funded by NSF OPP Grants 1503910, 1504191, 1504288,
and 1504521 and National Geographic Grant CP4-171R-17. Additionally, this research was supported by the NOAA Climate and Global Change Postdoctoral Fellowship Program, administered by UCAR’s Cooperative Programs for the Advancement of Earth System Science (CPAESS) under award #NA18NWS4620043B. These observations would not be possible without the skilled engineering team who developed the autonomous kayaks—including Jasmine Nahorniak, June Marion, Nick McComb, Anthony Grana, and Corwin Perren—and also the Captain and crew of the M/V Amber Anne. We thank Donald Slater and an anonymous reviewer for valuable feedback that improved this manuscript. Data availability: All of the oceanographic data collected by ship and kayak have been archived with the National Centers for Environmental Information (Accession 0189574, https://accession.nodc.noaa.gov/ 0189574). The glacier data have been archived at the Arctic Data Center (https://doi.org/10.18739/A22G44).Ye
Republicanism and the political economy of democracy
Europe is experiencing rapidly accelerating poverty and social exclusion, following half a decade of financial crisis and austerity politics. The key problem behind Europe's malaise, in our view, is the economic disenfranchisement of large parts of its population in the winner-takes-all-society. This article proposes that we examine the contribution of republican political theory as a distinctive approach that provides us with the conceptual and normative resources to reclaim what we call the political economy of democracy, the constellation of political and economic institutions aimed at promoting broad economic sovereignty and individuals' capacities to govern their own lives. This article identifies three key ideas that together constitute a distinctively republican approach to political economy: (1) establish an economic floor; (2) impose an economic ceiling to counter excess economic inequality; and (3) democratize the governance and regulation of the main economic institutions
Emergence: Key physical issues for deeper philosophical inquiries
A sketch of three senses of emergence and a suggestive view on the emergence
of time and the direction of time is presented. After trying to identify which
issues philosophers interested in emergent phenomena in physics view as
important I make several observations pertaining to the concepts, methodology
and mechanisms required to understand emergence and describe a platform for its
investigation. I then identify some key physical issues which I feel need be
better appreciated by the philosophers in this pursuit. I end with some
comments on one of these issues, that of coarse-graining and persistent
structures.Comment: 16 pages. Invited Talk at the Heinz von Foerster Centenary
International Conference on Self-Organization and Emergence: Emergent Quantum
Mechanics (EmerQuM11). Nov. 10-13, 2011, Vienna, Austria. Proceedings to
appear in J. Phys. (Conf. Series
Emergence: Key physical issues for deeper philosophical inquiries
A sketch of three senses of emergence and a suggestive view on the emergence
of time and the direction of time is presented. After trying to identify which
issues philosophers interested in emergent phenomena in physics view as
important I make several observations pertaining to the concepts, methodology
and mechanisms required to understand emergence and describe a platform for its
investigation. I then identify some key physical issues which I feel need be
better appreciated by the philosophers in this pursuit. I end with some
comments on one of these issues, that of coarse-graining and persistent
structures.Comment: 16 pages. Invited Talk at the Heinz von Foerster Centenary
International Conference on Self-Organization and Emergence: Emergent Quantum
Mechanics (EmerQuM11). Nov. 10-13, 2011, Vienna, Austria. Proceedings to
appear in J. Phys. (Conf. Series
Iceberg topography and volume classification using TanDEM-X interferometry
Icebergs in polar regions affect water salinity, alter marine habitats, and impose serious hazards on maritime operations and navigation. These impacts mainly depend on the iceberg volume, which remains an elusive parameter to measure. We investigate the capability of TanDEM-X bistatic single-pass synthetic aperture radar interferometry (InSAR) to derive iceberg subaerial morphology and infer total volume. We cross-verify InSAR results with Operation IceBridge (OIB) data acquired near Wordie Bay, Antarctica, as part of the OIB/TanDEM-X Antarctic Science Campaign (OTASC). While icebergs are typically classified according to size based on length or maximum height, we develop a new volumetric classification approach for applications where iceberg volume is relevant. For icebergs with heights exceeding 5 m, we find iceberg volumes derived from TanDEM-X and OIB data match within 7 %. We also derive a range of possible iceberg keel depths relevant to grounding and potential impacts on subsea installations. These results suggest that TanDEM-X could pave the way for future single-pass interferometric systems for scientific and operational iceberg mapping and classification based on iceberg volume and keel depth
Ursinus College Alumni Journal, March 1968
Why can\u27t we have plays like we used to have? • Alumni respond to a questionnaire • Dr. Maurice Whitman Armstrong • Alumni Loyalty Fund mid-year report • From the President • Interview: Dr. Millard E. Gladfelter • Some plain facts about Ursinus • Candidates for office • Committee on future giving meets • Campus clippings: New faculty members; Future beyond tomorrow; Ursinus evaluated; Advanced study; New history chairman • Nudity in films: a point of view • For the sake of an old pal • Sporting scene: Basketball team excels; Cross-country team undefeated; All sports banquet; Wrestling • Class notebook • Weddings • Births • In memoriam • Letters to the editorhttps://digitalcommons.ursinus.edu/alumnijournal/1091/thumbnail.jp
A Changing Hydrological Regime: Trends in Magnitude and Timing of Glacier Ice Melt and Glacier Runoff in a High Latitude Coastal Watershed
With a unique biogeophysical signature relative to other freshwater sources, meltwater
from glaciers plays a crucial role in the hydrological and ecological regime of high latitude coastal areas.
Today, as glaciers worldwide exhibit persistent negative mass balance, glacier runoff is changing in both
magnitude and timing, with potential downstream impacts on infrastructure, ecosystems, and ecosystem
resources. However, runoff trends may be difficult to detect in coastal systems with large precipitation
variability. Here, we use the coupled energy balance and water routing model SnowModel-HydroFlow to
examine changes in timing and magnitude of runoff from the western Juneau Icefield in Southeast Alaska
between 1980 and 2016. We find that under sustained glacier mass loss (−0.57 ± 0.12 m w. e. a−1), several
hydrological variables related to runoff show increasing trends. This includes annual and spring glacier ice
melt volumes (+10% and +16% decade−1) which, because of higher proportions of precipitation, translate
to smaller increases in glacier runoff (+3% and +7% decade−1) and total watershed runoff (+1.4% and
+3% decade−1). These results suggest that the western Juneau Icefield watersheds are still in an increasing
glacier runoff period prior to reaching “peak water.” In terms of timing, we find that maximum glacier ice
melt is occurring earlier (2.5 days decade−1), indicating a change in the source and quality of freshwater
being delivered downstream in the early summer. Our findings highlight that even in maritime climates
with large precipitation variability, high latitude coastal watersheds are experiencing hydrological regime
change driven by ongoing glacier mass loss.The authors would like to thank
W. P. Dryer, C. McNeil, S. Candela,
and J. Pierce for help in the field. R.
Crumley and C. Cosgrove assisted with
SnowModel initialization. The Juneau
Icefield Research Program (JIRP) provided field data and logistical support.
E. Berthier provided geodetic data, F.
Ziemen contributed model results, and
C. McNeil provided assistance with datasets on behalf of both USGS and JIRP.
The authors thank three anonymous
reviewers for suggestions that have
greatly improved the manuscript. This
work was supported by a Department
of Interior Alaska Climate Adaptation
Science Center graduate fellowship
awarded under Cooperative Agreement
G17AC00213, by NASA under award
NASANNX16AQ88G, by the National
Science Foundation under award
OIA-1208927 and by the State of Alaska
(Experimental Program for Stimulating
Competitive Research–Alaska Adapting
to Changing Environments award), and
by the University of Alaska Fairbanks
Resilience and Adaptation Program.
The authors acknowledge that field
work was conducted on the traditional
and unceded lands of the Lingit Aani
(Tlingit), Michif Piyii (Métis), and
Dënéndeh nations.Ye
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