1,786 research outputs found

    Deformation and Aerodynamic Performance of a Ram-Air Wing

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    Ram-air wings form an ever increasing market of soft fabric, air inflated wings. They are primairily used in air sports such as parachuting, paragliding and kiting. Ram-air kites may also be used for electric power generation by letting the kite pull a cable from a drum that is connected to a generator. An example if this principle is the Laddermill concept. But since ram-air wings are flexible by nature they will deform and depart from their intended design shape when they are loaded by aerodynamic forces. These deformations generally affect the performance of the wings adversely. Kites with a higher lift-to-drag ratio on the Laddermill could mean a direct increase of the energy produced per square meter of kite. Besides this benefit for the Laddermill there is a huge, world-wide market of parachuting, paragliding and kiting that can benefit from more research and a better understanding of the deformation and aerodynamic performance of ram-air wings. The goals of this thesis are to be able to point out where a ram-air kite departs from the intended design shape, to investigate how well the kite performs, to understand how the deformations affect the airflow and to make suggestions for possible improvements of the design. Since little has been published about these subjects this report will most of all form a basis for further research. This report presents a method to analyse the shape and the aerodynamics of a ram-air kite. The kite is tested in the windtunnel. Its 3D shape is captured using two techniques: photogrammetry and laser scanning. Using the geometry data the structural deformation of the wing is dissected. With computational fluid dynamics the aerodynamics of the deformed shape is analyzed. An extra result of this study is the comparison of photogrammetry and laser scanning in terms of their suitability to capture the 3D shape of the ram-air kite. A number of interesting deformations and flow features were found on the ram-air wing: - Theoretically the bumps (ballooning) and grooves on a ram-air wing hinder the spanwise flow on a 3-dimensional wing, but in practise this effect is only visible on small parts of the upper surface. - The pull of the suspension lines on the under surface and the internal construction of the wing make the upper surface of the wing deform. This results in a decrease of the upper surface curvature, especially near the nose. This curvature decrease causes a loss of lift of at least 5%. - Because the flat, 2-dimensional fabric is inflated into a 3-dimensional shape the fabric wrinkles. The wrinkles continue from the top and bottom surface into the ribs that internally connect and support the top and bottom surface. On average these wrinkles shorten the ribs in chordwise direction by 3.5%. This decreases the surface area of the wing and it makes the ribs effectively thicker. Many more details became visible with the thorough analysis of the wing’s shape. The conclusion is that the performance of the ram-air wing can be improved by changing these details. The photogrammetry measuring technique gave better results than laser scanning and is very suitable tool to make these details visible. It allows a designer to identify where the real flying shape deviates from the design shape. This can help kite designers and designers of other ram-air wings to reverse-Aerospace Engineerin

    Great Expectatrics: Great Papers, Great Journals, Great Econometrics

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    The paper discusses alternative Research Assessment Measures (RAM), with an emphasis on the Thomson Reuters ISI Web of Science database (hereafter ISI). The various ISI RAM that are calculated annually or updated daily are defined and analysed, including the classic 2-year impact factor (2YIF), 5-year impact factor (5YIF), Immediacy (or zero-year impact factor (0YIF)), Eigenfactor score, Article Influence, C3PO (Citation Performance Per Paper Online), h-index, Zinfluence, and PI-BETA (Papers Ignored - By Even The Authors). The ISI RAM data are analysed for 8 leading econometrics journals and 4 leading statistics journals. The application to econometrics can be used as a template for other areas in economics, for other scientific disciplines, and as a benchmark for newer journals in a range of disciplines. In addition to evaluating high quality research in leading econometrics journals, the paper also compares econometrics and statistics, alternative RAM, highlights the similarities and differences in alternative RAM criteria, finds that several ISI RAM capture similar performance characteristics for the leading econometrics and statistics journals while the new PI-BETA criterion is not highly correlated with any of the other ISI RAM, and hence conveys additional information regarding ISI RAM, highlights major research areas in leading journals in econometrics, and discusses some likely future uses of RAM.Research assessment measures, impact factors, Immediacy, Eigenfactor score, Article influence, h-index, C3PO, Zinfluence, PI-BETA

    Scientometric portrait of Ram Gopal Rastogi

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    Publication productivity of Indian scientist (R.G. Rastogi) has been documented. Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)

    Great Expectatrics: Great Papers, Great Journals, Great Econometrics

    No full text
    The paper discusses alternative Research Assessment Measures (RAM), with an emphasis on the Thomson Reuters ISI Web of Science database (hereafter ISI). The various ISI RAM that are calculated annually or updated daily are defined and analysed, including the classic 2-year impact factor (2YIF), 5-year impact factor (5YIF), Immediacy (or zero-year impact factor (0YIF)), Eigenfactor score, Article Influence, C3PO (Citation Performance Per Paper Online), h-index, Zinfluence, and PI-BETA (Papers Ignored - By Even The Authors). The ISI RAM data are analysed for 8 leading econometrics journals and 4 leading statistics journals. The application to econometrics can be used as a template for other areas in economics, for other scientific disciplines, and as a benchmark for newer journals in a range of disciplines. In addition to evaluating high quality research in leading econometrics journals, the paper also compares econometrics and statistics, alternative RAM, highlights the similarities and differences in alternative RAM criteria, finds that several ISI RAM capture similar performance characteristics for the leading econometrics and statistics journals while the new PI-BETA criterion is not highly correlated with any of the other ISI RAM, and hence conveys additional information regarding ISI RAM, highlights major research areas in leading journals in econometrics, and discusses some likely future uses of RAM.Research assessment measures; impact factors; Immediacy; Eigenfactor score; Article influence; h-index; C3PO; Zinfluence; PI-BETA

    Combatting Exclusions through Law

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    Delhi High Court\u27s Socio-Economic Rights Adjudication: Some Insights

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    Indian constitutionalism has always occupied a central place in the global academic discourse on socio-economic rights. This is especially due to the design of the Indian Constitution (where socio-economic rights are constitutionalized in the form of non-enforceable \u27Directive Principles of State Policy\u27) and the creative interpretations of the post-emergency Supreme Court. Nearly all academic studies, however, have focussed singularly on the jurisprudence of the Supreme Court. The decisions of the other constitutional courts in India - the High Courts have largely gone unstudied. Thus, there is lacunae in academic literature on Indian socio-economic rights enforcement. In this essay, we seek to examine the Delhi High Court\u27s socio-economic rights adjudication. More specifically, we assess the interlinking of rights, nature and design of remedies, measure its decisions vis-h-vis theories of judicial review, explore the tools used to balance information asymmetry and highlight the manner of judicial activism. The method of analysis is interpretive.

    Steady-State Solver for a Ram-Air Kite Aeroelastic Model Based on Dynamic Relaxation

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    We present a computationally efficient steady-state solution method to model the aeroelastic deformation of a ram-air kite for airborne wind energy applications. The kite’s weight in comparison to the aerodynamic forces is small which justifies a quasi-steady analysis, neglecting gravitational and inertial force effects [1]. The approach is suitable to efficiently determine the deformed configuration of a ram-air kite for design and optimization purposes as found in [2]. Because of the expected large deformations and changes in the flow field, fluid-structure interaction has to be taken into account in the analysis.Wind Energ

    Night-Time Stories from The Panchatantra

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    Similar to Arora's 101 Moral Stories of Grandpa, this hardbound book with dust-jacket has 100 pages. The T of C on 6 lists fifteen numbered stories. This book is remarkable for offering a large picture on almost every page. New to me is The Sparrows & the Tusker (51). An elephant breaks off a limb and unwittingly destroys a nest. The sparrows get help from a woodpecker, a fly, and a frog, Together they lull the elephant, blind him by pecking out his eyes, and mislead him into a deep pit he mistakes for a water-hole. It is nice to meet old friends from the Panchatantra and Kalila and Dimna tradition, and I enjoy Ram-Lakshman's art. One of the best images here is that of the lion springing into the well as the hare runs away (99). The dust-jacket is glued to the covers.This is a hardbound book (hard cover)This book has a dust jacket (book cover)Retold by Reinu Bhano

    Delhi High Court\u27s Socio-Economic Rights Adjudication: Some Insights

    No full text
    Indian constitutionalism has always occupied a central place in the global academic discourse on socio-economic rights. This is especially due to the design of the Indian Constitution (where socio-economic rights are constitutionalized in the form of non-enforceable \u27Directive Principles of State Policy\u27) and the creative interpretations of the post-emergency Supreme Court. Nearly all academic studies, however, have focussed singularly on the jurisprudence of the Supreme Court. The decisions of the other constitutional courts in India - the High Courts have largely gone unstudied. Thus, there is lacunae in academic literature on Indian socio-economic rights enforcement. In this essay, we seek to examine the Delhi High Court\u27s socio-economic rights adjudication. More specifically, we assess the interlinking of rights, nature and design of remedies, measure its decisions vis-h-vis theories of judicial review, explore the tools used to balance information asymmetry and highlight the manner of judicial activism. The method of analysis is interpretive.
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