173,997 research outputs found
A stronger Bell argument for quantum non-locality
No full textIt 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
Richard Bell: Uz vs. Them
No full textRichard Bell, one of Australia's most collectable leading contemporary artists, has established a significant reputation as a political commentator and an "enfant terrible" in Indigenous art over the past two decades. This stunningly illustrated catalogue features more than 26 colour plates of his provocative and often humorous works. With their bold use of images and text, they force viewers to face the troubling issue of racism in Australia. Bell's inspiration is complex and multi-layered. He is an avid appropriator, borrowing from other artists, periods, and cultures, including Roy Lichtenstein, Jasper Johns, Jackson Pollock, and Aboriginal painter Emily Kam Kngwarreye, among others. He works across a wide range of media, including painting, performance, and video, producing powerful messages that confront and unsettle: about Aboriginal and non-Aboriginal Australians' relationship to each other, about their country's history and about art itself. Published in conjunction with the exhibition Richard Bell: Uz vs. Them: Tufts University Art Gallery, Medford, Massachusetts, September 14-November 20, 2011; University of Kentucky Art Museum, Lexington, Kentucky, February 12-May 6, 2012; Victoria H. Myhren Gallery, University of Denver, Denver, Colorado, September 13-December 9, 2012; Indiana University Art Museum, Bloomington, Indiana. March 1-May 5, 2013Arts, Education & Law Group, Queensland College of ArtNo Full Tex
D-FINITENESS, RATIONALITY, and HEIGHT
No full textMotivated by a result of van der Poorten and Shparlinski for univariate power series, Bell and Chen prove that if a multivariate power series over a field of characteristic 0 is D-finite and its coefficients belong to a finite set, then it is a rational function. We extend and strengthen their results to certain power series whose coefficients may form an infinite set. We also prove that if the coefficients of a univariate D-finite power series “look like” the coefficients of a rational function, then the power series is rational. Our work relies on the theory of Weil heights, the Manin–Mumford theorem for tori, an application of the Subspace Theorem, and various combinatorial arguments involving heights, power series, and linear recurrence sequences
Experimental Study of Dual Bell Nozzles
No full textAn experimental study was conducted testing Dual-bell nozzles in various conditions at DLR’s cold gas test stand. The stability of the nozzle flow has been verified by measuring the pressure ratio values by flow transition and retransition, to ensure a hysteresis between the two operation modes. The transition duration and the velocity of the transition front in the nozzle extension were calculated using pressure measurement and Schlieren optics to demonstrate the feasibility of the Dual-Bell concept
Empirical measurements of small unmanned aerial vehicle co-axial rotor systems
No full textSmall unmanned aerial vehicles (SUAV) are beginning to dominate the area of intelligence, surveillance, target acquisition and reconnaissance (ISTAR) in forward operating battlefield scenarios. Of particular interest are vertical take-off and landing (VTOL) variants. Within this category co-axial rotor designs have been adopted due to their inherent advantages of size and power to weight ratio. The inter-rotor spacing attribute of a co-axial rotor system appears to offer insight into the optimum design characteristic. The H/D ratio has been cited as a significant factor in many research papers, but to date has lacked an empirical value or an optimal dimensionless condition. In this paper the H/D ratio of a SUAV has been explored thoroughly, reviewing the performance of these systems at incremental stages, the findings from this study have shown that a range of H/D ratios in the region of (0.41-0.65) is advantageous in the performance of SUAV systems. This finding lends itself to the theory of inter-rotor spacing as a non-dimensionally similar figure, which cannot be applied across a spectrum of systems; this could be attributed to the viscous losses of flight at low Reynolds Numbers (< 50,000
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
Inequality in Scotland: new perspectives
No full textThis paper presents new evidence on inequality in Scotland. It begins by explaining why inequality is taking centre stage in both national and international debates at this time. It then presents a variety of evidence about inequality in Scotland. It uses data from large-scale surveys over the last three decades to identify key economic and social trends that have influenced inequality. It goes on to analyse the effectiveness of policies in Scotland that are intended to redistribute between rich and poor. These are largely concerned with taxes and welfare benefits, some of which will fall under the control of the Scottish Parliament in the near future. It goes on to discuss the redistributive effects of policies that have other objectives - such as mitigating the effect of climate change, managing the housing market etc. This analysis is particularly novel in a Scottish context
Progress towards Bell-type polarization experiment with thermal neutrons
No full textExperimental tests of Bell-type inequalities distinguishing between quantum mechanics and local realistic theories remain of considerable interest if performed on massive particles, for which no conclusive result has yet been obtained. Only two-particle experiments may specifically test the concept of spatial nonlocality in quantum theory, whereas single-particle experiments may generally test the concept of quantum noncontextuality. Here we have performed the first Bell-type experiment with a beam of thermal-neutron pairs in the singlet state of spin, as originally suggested by J. S. Bell. These measurements confirm the quantum-theoretical predictions, in agreement with the results of the well-known polarization experiments carried out on optical photons years ago
Faust : A Tragedy ; Part II. ; As Completed In 1831 / by J. W. Goethe. Transl. Into English Verse [John Bell Macdonald]
No full textFAUST : A TRAGEDY ; PART II. ; AS COMPLETED IN 1831 / BY J. W. GOETHE. TRANSL. INTO ENGLISH VERSE [JOHN BELL MACDONALD]
Faust : A Tragedy ; Part II. ; As Completed In 1831 / by J. W. Goethe. Transl. Into English Verse [John Bell Macdonald] (1)
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