96,440 research outputs found

    Effect of varying internal geometry on the static performance of rectangular thrust-reverser ports

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    An investigation has been conducted to evaluate the effects of several geometric parameters on the internal performance of rectangular thrust-reverser ports for nonaxisymmetric nozzles. Internal geometry was varied with a test apparatus which simulated a forward-flight nozzle with a single, fully deployed reverser port. The test apparatus was designed to simulate thrust reversal (conceptually) either in the convergent section of the nozzle or in the constant-area duct just upstream of the nozzle. The main geometric parameters investigated were port angle, port corner radius, port location, and internal flow blocker angle. For all reverser port geometries, the port opening had an aspect ratio (throat width to throat height) of 6.1 and had a constant passage area from the geometric port throat to the exit. Reverser-port internal performance and thrust-vector angles computed from force-balance measurements are presented

    Static internal performance including thrust vectoring and reversing of two-dimensional convergent-divergent nozzles

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    The effects of geometric design parameters on two dimensional convergent-divergent nozzles were investigated at nozzle pressure ratios up to 12 in the static test facility. Forward flight (dry and afterburning power settings), vectored-thrust (afterburning power setting), and reverse-thrust (dry power setting) nozzles were investigated. The nozzles had thrust vector angles from 0 deg to 20.26 deg, throat aspect ratios of 3.696 to 7.612, throat radii from sharp to 2.738 cm, expansion ratios from 1.089 to 1.797, and various sidewall lengths. The results indicate that unvectored two dimensional convergent-divergent nozzles have static internal performance comparable to axisymmetric nozzles with similar expansion ratios

    The Stratigraphic Record of Pre-breakup Geodynamics: Evidence from the Barrow Delta, offshore Northwest Australia

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    The structural and stratigraphic evolution of rift basins and passive margins has been widely studied, with many analyses demonstrating that delta systems can provide important records of post-rift geodynamic processes. However, the apparent lack of ancient syn-breakup delta systems and the paucity of seismic imaging across continent-ocean boundaries means the transition from continental rifting to oceanic spreading remains poorly understood. The Early Cretaceous Barrow Group of the North Carnarvon Basin, offshore NW Australia was a major deltaic system that formed during the latter stages of continental rifting, and represents a rich sedimentary archive, documenting uplift, subsidence and erosion of the margin. We use a regional database of 2D and 3D seismic and well data to constrain the internal architecture of the Barrow Group. Our results highlight three major depocentres: the Exmouth and Barrow sub-basins, and southern Exmouth Plateau. Over-compaction of pre-Cretaceous sedimentary rocks in the South Carnarvon Basin, and pervasive reworking of Permian and Triassic palynomorphs in the offshore Barrow Group, suggests that the onshore South Carnarvon Basin originally contained a thicker sedimentary succession, which was uplifted and eroded prior to breakup. Backstripping of sedimentary successions encountered in wells in the Exmouth Plateau depocentre indicate anomalously rapid tectonic subsidence (≤0.24 mm yr-1) accommodated Barrow Group deposition, despite evidence for minimal, contemporaneous upper crustal extension. Our results suggest that classic models of uniform extension cannot account for the observations of uplift and subsidence in the North Carnarvon Basin, and may indicate a period of depth-dependent extension or dynamic topography preceding breakup

    Prognostic factors of survival in patients treated with nab-paclitaxel plus gemcitabine regimen for advanced or metastatic pancreatic cancer: A single institutional experience.

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    The objectives of this study were to evaluate the effectiveness of nab-paclitaxel plus gemcitabine (NAB-P/GEM) regimen in an unselected population of patients with advanced inoperable or metastatic pancreatic cancer (PC), and to identify the prognostic factors influencing overall survival (OS). EXPERIMENTAL DESIGN: Patients with age < 85 years, ECOG-performance status (PS) < 3, and adequate renal, hepatic and hematologic function were eligible. NAB-P (125 mg/m2) and GEM (1000 mg/m2) day 1,8,15 every 4 weeks were employed for 3-6 cycles or until highest response. RESULTS: Overall, 147 cycles (median 4, range 1-11 cycles) were administered on thirty-seven consecutive patients (median 66 years old, range 40-82) treated. The median overall progression-free survival and OS were 6.2 and 9.2 months, respectively. The G 3-4 dose-limiting toxicity were neutropenia (20.7%), severe anemia (17.2%), and cardiovascular toxicity (10.3%). PS, number of cycles, baseline CA 19-9 and LDH serum levels, were found to be significantly related to OS. The multivariate analysis showed that both number of cycles (HR = 9.14, 95% CI 1.84-45.50, p = 0.001) and PS (HR = 13.18, 95% CI 2.73-63.71, p = 0.001) were independently associated with OS. CONCLUSION: NAB-P/GEM regimen should be used in all patients with advanced or metastatic PC, with the exception of those with serious contraindications to chemotherapy, such as severe renal or hepatic impairment or major cardiovascular diseases

    Photonic polarization gears for ultra-sensitive angular measurements

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    Quantum metrology bears a great promise in enhancing measurement precision, but is unlikely to become practical in the near future. Its concepts can nevertheless inspire classical or hybrid methods of immediate value. Here, we demonstrate NOON-like photonic states of m quanta of angular momentum up to m=100, in a setup that acts as a "photonic gear", converting, for each photon, a mechanical rotation of an angle {\theta} into an amplified rotation of the optical polarization by m{\theta}, corresponding to a "super-resolving" Malus' law. We show that this effect leads to single-photon angular measurements with the same precision of polarization-only quantum strategies with m photons, but robust to photon losses. Moreover, we combine the gear effect with the quantum enhancement due to entanglement, thus exploiting the advantages of both approaches. The high "gear ratio" m boosts the current state-of-the-art of optical non-contact angular measurements by almost two orders of magnitude.Comment: 10 pages, 4 figures, + supplementary information (10 pages, 3 figures

    Rights-based reasoning in discussions about lesbian and gay issues: implications for moral educators

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    Despite a paucity of psychological research exploring the interface between lesbian and gay issues and human rights, a human rights framework has been widely adopted in debates to gain equality for lesbians and gay men. Given this prominence within political discourse of human rights as a framework for the promotion of positive social change for lesbians and gay men, the aim of this study was to explore the extent to which rights-based arguments are employed when talking about lesbian and gay issues in a social context. An analysis of six focus group discussions with students showed that when lesbian and gay issues are discussed, rights-based reasoning is employed intermittently, and in relation to certain issues more so than others. The implications of these findings for moral education aimed at promoting positive social change for lesbians and gay men are discussed.</p

    Static internal performance of single expansion-ramp nozzles with thrust vectoring and reversing

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    The effects of geometric design parameters on the internal performance of nonaxisymmetric single expansion-ramp nozzles were investigated at nozzle pressure ratios up to approximately 10. Forward-flight (cruise), vectored-thrust, and reversed-thrust nozzle operating modes were investigated

    Co-constructing a new framework for evaluating social innovation in marginalized rural areas

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    The EU funded H2020 project \u2018Social Innovation in Marginalised Rural Areas\u2019 (SIMRA; www.simra-h2020.eu) has the overall objective of advancing the state-of-the-art in social innovation. This paper outlines the process for co- developing an evaluation framework with stakeholders, drawn from across Europe and the Mediterranean area, in the fields of agriculture, forestry and rural development. Preliminary results show the importance of integrating process and outcome-oriented evaluations, and implementing participatory approaches in evaluation practice. They also raise critical issues related to the comparability of primary data in diverse regional contexts and highlight the need for mixed methods approaches in evaluation

    Shutters, Boxes, But No Paradoxes: Time Symmetry Puzzles in Quantum Theory

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    The ``N-Box Experiment'' is a much-discussed thought experiment in quantum mechanics. It is claimed by some authors that a single particle prepared in a superposition of N+1 box locations and which is subject to a final ``post-selection'' measurement corresponding to a different superposition can be said to have occupied ``with certainty'' N boxes during the intervening time. However, others have argued that under closer inspection, this surprising claim fails to hold. Aharonov and Vaidman have continued their advocacy of the claim in question by proposing a variation on the N-box experiment, in which the boxes are replaced by shutters and the pre- and post-selected particle is entangled with a photon. These authors argue that the resulting ``N-shutter experiment'' strengthens their original claim regarding the N-box experiment. It is argued in this paper that the apparently surprising features of this variation are no more robust than those of the N-box experiment and that it is not accurate to say that the particle is ``with certainty'' in all N shutters at any given time.Comment: Presentation improved; to appear in International Studies in Philosophy of Scienc
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