3,262 research outputs found
Interns and Institutions: Interactions Between Unpaid Interns and Public Policy
Political, and especially Congressional, internships are all but mandatory to launch a career in politics. This text examines the demographics of how these internships are dispersed, how they are paid, who is paid, and how this manifests in full-time Congressional staff demographics. Data shows that both paid and unpaid Congressional internships belong disproportionately to white students. Top staff in the House of Representatives is similarly disproportionately white. The text also examines the inherent danger of working in Congress and the broader case for paid internships
Testing of molded high temperature plastic actuator road seals for use in advanced aircraft hydraulic systems
Molded high temperature plastic first and second stage rod seal elements were evaluated in seal assemblies to determine performance characteristics. These characteristics were compared with the performance of machined seal elements. The 6.35 cm second stage Chevron seal assembly was tested using molded Chevrons fabricated from five molding materials. Impulse screening tests conducted over a range of 311 K to 478 K revealed thermal setting deficiencies in the aromatic polyimide molding materials. Seal elements fabricated from aromatic copolyester materials structurally failed during impulse cycle calibration. Endurance testing of 3.85 million cycles at 450 K using MIL-H-83283 fluid showed poorer seal performance with the unfilled aromatic polyimide material than had been attained with seals machined from Vespel SP-21 material. The 6.35 cm first stage step-cut compression loaded seal ring fabricated from copolyester injection molding material failed structurally during impulse cycle calibration. Molding of complex shape rod seals was shown to be a potentially controllable technique, but additional molding material property testing is recommended
Testing of improved polyimide actuator rod seals at high temperature and under vacuum conditions for use in advanced aircraft hydraulic systems
Polyimide second-stage rod seals were evaluated to determine their suitability for applications in space station environments. The 6.35-cm (2.5-in.)K-section seal was verified for thermal cycling operation between room temperature and 478 K (400 F) and for operation in a 133 micron PA(0.000001 mm Hg) vacuum environment. The test seal completed the scheduled 96 thermal cycles and 1438 hr in vacuum with external rod seal leakage well within the maximum allowable of two drops per 25 actuation cycles. At program completion, the seals showed no signs of structural degradation. Posttest inspection showed the seals retained a snug fit against the shaft and housing walls, indicating additional wear life capability. Evaluation of a molecular flow section during vacuum testing, to inhibit fluid loss through vaporization, showed it to be beneficial with MIL-H-5606, a petroleum-base fluid, in comparison with MIL-H-83282, a synthetic hydrocarbon-base fluid
Chemical constituents of the bark of ryparosa kunstleri (Flacourtiaceae)
The bark of Ryparosa kunstleri yielded the triterpenes friedelin, trichadenic acid B, and the new 3B-p-coumaroyl
trichadenic acid as its major constituents. Stictic acid, a depsidone, was also isolated but was deduced to be a
contaminant
The Commercial Application of Missile/Space Technology, Parts 1 and 2
This report is concerned with the transfer of technology from missile and space programs to non-missile/space applications in the United States. It presents the findings of a University of Denver Research Institute study sponsored by a National Aeronautics and Space Administration (NASA) grant awarded in November 1961. Initial stimulation for the unsolicited proposal leading to this study came from a 1960 Brookings Institution report to NASA, Proposed Studies on the Implications of Peaceful Space Activities for Human Affairs
funcX: A Federated Function Serving Fabric for Science
Exploding data volumes and velocities, new computational methods and
platforms, and ubiquitous connectivity demand new approaches to computation in
the sciences. These new approaches must enable computation to be mobile, so
that, for example, it can occur near data, be triggered by events (e.g.,
arrival of new data), be offloaded to specialized accelerators, or run remotely
where resources are available. They also require new design approaches in which
monolithic applications can be decomposed into smaller components, that may in
turn be executed separately and on the most suitable resources. To address
these needs we present funcX---a distributed function as a service (FaaS)
platform that enables flexible, scalable, and high performance remote function
execution. funcX's endpoint software can transform existing clouds, clusters,
and supercomputers into function serving systems, while funcX's cloud-hosted
service provides transparent, secure, and reliable function execution across a
federated ecosystem of endpoints. We motivate the need for funcX with several
scientific case studies, present our prototype design and implementation, show
optimizations that deliver throughput in excess of 1 million functions per
second, and demonstrate, via experiments on two supercomputers, that funcX can
scale to more than more than 130000 concurrent workers.Comment: Accepted to ACM Symposium on High-Performance Parallel and
Distributed Computing (HPDC 2020). arXiv admin note: substantial text overlap
with arXiv:1908.0490
Quantification of the differences between quenched and annealed averaging for RNA secondary structures
The analytical study of disordered system is usually difficult due to the
necessity to perform a quenched average over the disorder. Thus, one may resort
to the easier annealed ensemble as an approximation to the quenched system. In
the study of RNA secondary structures, we explicitly quantify the deviation of
this approximation from the quenched ensemble by looking at the correlations
between neighboring bases. This quantified deviation then allows us to propose
a constrained annealed ensemble which predicts physical quantities much closer
to the results of the quenched ensemble without becoming technically
intractable.Comment: 9 pages, 14 figures, submitted to Phys. Rev.
The Common Cause of All Advanced and Progressive Mankind: Proletarian Internationalism, Spain, and the American Communist Press, 1936 - 1937
In July 1936, units of the Spanish military, backed by a collection of domestic right-wing elements and by fascist governments elsewhere in Europe, staged a rebellion against the legally constituted national government that had been elected five months previously. The governing bloc, an ideologically broad coalition of liberal republicans, Marxists, and anarchists known as the People\u27s Front, embodied the strategy formulated by Stalin and the Communist International (Comintern) in Moscow to stem the advance of international fascism and mitigate the danger it posed to the Soviet Union and, by extension, the communist movement and the global radical working class it represented. During the destructive and bloody civil war that ensued, the Comintern sponsored recruitment of anti-fascist volunteer fighters from around the world. Before the war ended, nearly 3,000 Americans had surreptitiously traveled to Spain to defend its republican government. This thesis addresses the question of how these volunteers came to develop an allegiance to their global political and social movement strong enough to motivate them to risk death in what they perceived to be its defense against fascism.
Drawing on the theoretical formulations of political scientists Benedict Anderson and David Malet, this thesis will demonstrate that over the course of a century, radical proletarian internationalism developed into a community of working-class revolutionaries, mostly within or allied to communist parties, whose shared ideological formulations and sociopolitical aspirations bound them together, irrespective of nationality. American members of that global community - whose numbers and influence had recently expanded in the context of the Great Depression and the People\u27s Front strategy of liberal-left conciliation - had their perceptions and priorities about the Spanish crisis shaped by the American communist press. Examination and analysis of its coverage of the political, social, and military dimensions of the conflict there will demonstrate it to have been copious and persistent, imparting unmistakably to its readership the centrality of the Spanish people\u27s struggle against fascism in the defense of the global working class, whose political and social survival was at stake. The thesis will argue, in the context of the contentious historiography of American communism, that although the messages conveyed to American proletarian internationalists via the communist press reflected policies and priorities determined in Moscow and designed to serve the interests of the Soviet state, American anti-fascists were for the most part well informed ideologues whose decisions reflected both the concerted influences of their movement\u27s leadership as well as their own deep commitments to a more equitable world
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