60,021 research outputs found
A stronger Bell argument for quantum non-locality
Get PDFIt is widely accepted that the violation of Bell inequalities excludes local theories of the quantum realm. In this paper I present a stronger Bell argument which even forbids certain non-local theories. The remaining non-local theories, which can violate Bell inequalities, are characterised by the fact that at least one of the outcomes in some sense probabilistically depends both on its distant as well as on its local parameter. While this is not to say that parameter dependence in the usual sense necessarily holds, it shows that the received analysis of quantum non-locality as “outcome dependence or parameter dependence” is deeply misleading about what the violation of Bell inequalities implies
The Altitude Adaptive Dual Bell Nozzle
No full textThe dual bell nozzle has been found out to be one of the most promising concepts for alti-tude adaption of the nozzle jet. The wall contour inflection linking the base nozzle with the ex-tension provides two stable operating modes, circumventing the area ratio limitation inherent to conventional main stage engine nozzles. During the past decade, numerous experimental as well as analytical investigations have been conducted at the German Aerospace Center for a better understanding and the qualification of the dual bell concept for main stage engine application. Cold and hot flow tests aimed to point out the influence of the geometrical parameters on the flow behavior. The conditions for the transition from sea level to altitude mode and back, the hysteresis between these values, the duration of the transition and the resulting side load genera-tion were of particular interest. The contour optimization results in a trade-off between the tran-sition duration, stability and side load amplitude, all depending on the extension length. Out of the experimental work, it was possible to define the parameters for realistic dual bell nozzle geometries and to conduct an analytical study of the nozzle behavior during ascent of a parallel staged heavy launcher. The additional loss in sea level, the so-called drag effect, was evaluated for the chosen nozzle using DLR’s CFD in-house code Tau. The present paper gives an over-view on current experimental and analytical dual bell research activities
Bell Brandon
Get PDF80.7568.131 – “Bell Brandon” Composed by F. Woolcott/ Lyrics by T. Ellwood Garrett: Balmer and Weber: St. Louis: Minstrel, Ballad, Love Song: 1854: Song and Chorus
Experimental and numerical study of heat flux in dual bell nozzles
No full textThe characteristic contour inflection of a dual bell nozzle is the key to altitude adaption. In sea level conditions, it forces the flow to a symmetrical separation, limiting the side load
generation and increasing the thrust. After the transition, under high altitude conditions, the nozzle flows full, increasing the vacuum thrust. A hot flow experimental study has been conducted at the German Aerospace Center on a planar dual bell nozzle. The wall temperature distribution has been measured at various depths for the determination of the heat flux through the wall. The region of the inflection is of particular interest for the adjustment of the conventional cooling methods of dual bell nozzles. The contour inflection
leads to a local increase of the thermal loads. In addition to the tests, the flow behavior and thermal loads have been calculated with CFD method and compared with the experiment
Letter from Carl Hayden to Henry F. Ashurst
No full textLetter describing three enclosures, a letter from F. M. Gold, Carl T. Hayden's reply to Gold's letter, and a copy of a bill introduced by Cameron
Letter from A. F. Potter to Carl Hayden
No full textLetter from A. F. Potter to Carl T. Hayden describing John H. Page's request to build a railway for the Canyon Copper Company as "impractical"
DNA fusion gene vaccination mobilizes effective anti-leukemic cytotoxic T lymphocytes from a tolerized repertoire
No full textThe majority of known human tumor-associated antigens derive from non-mutated self proteins. T cell tolerance, essential to prevent autoimmunity, must therefore be cautiously circumvented to generate cytotoxic T cell responses against these targets. Our strategy uses DNA fusion vaccines to activate high levels of peptide-specific CTL. Key foreign sequences from tetanus toxin activate tolerance-breaking CD4+ T cell help. Candidate MHC class Ibinding tumor peptide sequences are fused to the C terminus for optimal processing and presentation. To model performance against a leukemia-associated antigen in a tolerized setting, we constructed a fusion vaccine encoding an immunodominant CTL epitopederived from Friend murine leukemia virus gag protein (FMuLVgag) and vaccinated tolerant FMuLVgag-transgenic (gag-Tg) mice. Vaccination with the construct induced epitopespecificIFN-c-producing CD8+ T cells in normal and gag-Tg mice. The frequency and avidity of activated cells were reduced in gag-Tg mice, and no autoimmune injury resulted. However, these CD8+ T cells did exhibit gag-specific cytotoxicity in vitro and in vivo. Also, epitope-specific CTL killed FBL-3 leukemia cells expressing endogenous FMuLVgag antigen and protected against leukemia challenge in vivo. These results demonstrate a simple strategy to engage anti-microbial T cell help to activate epitope-specific polyclonal CD8+ T cell responses from a residual tolerized repertoire
TAPASPlay: A game-based learning approach to foster computation thinking skills
No full textIn this paper we describe how to use a Game-Based Learning (GBL) approach to help end-user programmers to develop Computational Thinking (CT) skills. CT represents a framework consisting of a set of skills such as: Abstraction, decomposition and more in general problem solving expressed in a computational form (algorithmic thinking) that can be easily formalised into a computer program. Those skills are beneficial for end-user programmers in order to model a task for being tackled with computational tools, e.g. spreadsheets, domain specific and visual languages. TAPASPlay is an engaging GBL platform designed to help end-user to learn algorithmic thinking. © 2017 IEEE
Sustaining cultures of participation by fostering computational thinking skills through game-play
No full textThe adoption of a meta-design approach to system development opens up opportunities for transforming consumer cultures to cultures of participation. To this end, meta-design must create the conditions for such participation by supporting end users to appropriate the design skills necessary for system evolution, especially those related to Computational Thinking (CT), in new and engaging modalities. In this paper, we propose a novel approach to fostering CT skills that combines Game-Play learning with Tangible User Interfaces and Virtual Reality (VR). In the resulting system, called TAPASPlay, two players act as alchemists forging swords and shields to fight each other. They build them through a puzzle-based interaction with a tabletop interface, using smartphones as tangible objects. Finally, the players can enjoy the battle in VR using Google Cardboards. In this way, players can develop analysis, abstraction and problem solving abilities, i.e. suitable CT skills for meta-design and supporting cultures of participation. Copyright © 2017 for the individual papers by the papers' authors
Journey time estimation using single inductive loop detectors on non-signalised links
Get PDFThis paper describes two techniques designed to estimate vehicle journey times on non-signalised roads, using 250 ms digital loop-occupancy data produced by single inductive loop detectors. A mechanistic and a neural network approach provided historical journey time estimates every 30 s, based on the data collected from the previous 30 s period. These 30s estimates would provide the traffic network operator with immediate post-event congestion information on roads where no close circuit television cameras were present. The mechanistic approach estimated Journey times every 30 s between pairs of detectors, using the knowledge of vehicle speed derived from the loops and the distances between them. The 30s average loop-occupancy time per vehicle, average time-gap between vehicles and percentage occupancy parameters derived from the inductive loops were presented to a neural network for training along with the associated vehicles' measured journey times. The neural network was shown to consistently out-perform the mechanistic approach (in terms of the mean absolute percentage deviation from the mean measured travel time), particularly when using pairs of detector
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