61 research outputs found

    Distribution of Acoustic Power Spectra for an Isolated Helicopter Fuselage

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    The broadband aerodynamic noise can be studied, assuming isotropic flow, turbulence and decay. Proudman’s approach allows practical calculations of noise based on CFD solutions of RANS or URANS equations at the stage of post processing and analysis of the solution. Another aspect is the broadband acoustic spectrum and the distribution of acoustic power over a range of frequencies. The acoustic energy spectrum distribution in isotropic turbulence is non monotonic and has a maximum at a certain value of Strouhal number. In the present work the value of acoustic power peak frequency is determined using a prescribed form of acoustic energy spectrum distribution presented in papers by S. Sarkar and M. Y. Hussaini and by G. M. Lilley. CFD modelling of the flow around isolated helicopter fuselage model was considered using the HMB CFD code and the RANS equations

    Sagnac delay in the Kerr-dS space-time: Implications for Mach's principle

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    Relativistic twin paradox can have important implications for Mach's principle. It has been recently argued that the behavior of the time asynchrony (different aging of twins) between two flying clocks along closed loops can be attributed to the existence of an absolute spacetime, which makes Mach's principle unfeasible. In this paper, we shall revisit, and support, this argument from a different viewpoint using the Sagnac delay. This is possible since the above time asynchrony is known to be exactly the same as the Sagnac delay between two circumnavigating light rays re-uniting at the orbiting source/receiver. We shall calculate the effect of mass MM and cosmological constant Λ\Lambda on the delay in the general case of Kerr-de Sitter spacetime. It follows that, in the independent limits M0M\rightarrow 0, spin a0a\rightarrow 0 and Λ0\Lambda\rightarrow 0, while the Kerr-dS metric reduces to Minkowski metric, the clocks need not tick in consonance since there will still appear a non-zero observable Sagnac delay. While we do not measure spacetime itself, we do measure the Sagnac effect, which signifies an absolute substantive Minkowski spacetime instead of a void. We shall demonstrate a completely different limiting behavior of Sagnac delay, heretofore unknown, between the case of non-geodesic and geodesic source/observer motion.Comment: 15 pages. arXiv admin note: text overlap with arXiv:1709.0841

    Analysis and possibilities of increasing of labor potential in the regions of the Volga Federal District (Russian Federation)

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    © 2015, Mediterranean Center of Social and Educational Research. All rights reserved. The article proposes a method of estimating of employment potential of a territory and results of the comparative analysis of employment potential of the Volga Federal District regions based on the method. There were also identified some problems of the regions and suggested ways of solving them

    Reaction of Trichloro(o-phenylenedioxy)phosphorane with 1,2-Alkadienylphosphonates

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    Trichloro(o-phenylenedioxy)phosphorane reacts with 1,2-alkadienylphosphonates with selective replacement of the alkoxy group in the phosphinoyl moiety, yielding the corresponding 1,2-alkadienylchlorophosphonates and o-phenylene chlorophosphate

    Efficient and practical aerobic radical addition of thiophosphites to alkenes

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    Thiophosphites, but not phosphites, add onto alkenes under very mild conditions when treated with triethylborane and oxygen, and deliver the expected adducts in high isolated yields. This method, featuring a high atom economy, complements those described in literature and can be used to initiate tandem cascade processes. © 2001 Published by Elsevier Science Ltd

    On the solvability of geometrically nonlinear problem of sandwich plate theory

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    © 2015 I. B. Badriev et al. The problem of determining the stress-strain state rigidly fixed sandwich plate with transversely soft core in the presence of constraints (i.e., material nonlinearity) corresponding to the ideal elastic-plastic model for the core material is considered. Solvability of the generalized statement of the problem as a problem of finding the saddle point of some functionals is investigated

    Solving physically nonlinear equilibrium problems for sandwich plates with a transversally soft core

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    © 2015, Pleiades Publishing, Ltd. A generalized statement of the problem of determining the stress-strain state of sandwich plates with a transversally soft core in the presence of constraints is proposed. Its correctness is discussed. The generalized problem is stated as the problem of finding a saddle point of some functional. The existence and uniqueness of a solution is proved. An iterative method for solving the problem is proposed and its convergence is studied

    The Vacuole Model: New Terms in the Second Order Deflection of Light

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    The present paper is an extension of a recent work (Bhattacharya et al. 2010) to the Einstein-Strauss vacuole model with a cosmological constant, where we work out the light deflection by considering perturbations up to order M^3 and confirm the light bending obtained previously in their vacuole model by Ishak et al. (2008). We also obtain another local coupling term -((5{\pi}M^2{\Lambda})/8) related to {\Lambda}, in addition to the one obtained by Sereno (2008, 2009). We argue that the vacuole method for light deflection is exclusively suited to cases where the cosmological constant {\Lambda} disappears from the path equation. However, the original Rindler-Ishak method (2007) still applies even if a certain parameter {\gamma} of Weyl gravity does not disappear. Here, using an alternative prescription, we obtain the known term -(({\gamma}R)/2), as well as another new local term ((3{\pi}{\gamma}M)/2) between M and {\gamma}. Physical implications are compared, where we argue that the repulsive term -(({\gamma}R)/2) can be masked by the Schwarzschild term ((2M)/R) in the halo regime supporting attractive property of the dark matter.Comment: 15 page

    Students virtual and social identity in the process of humanities study: The problems of its correction

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    © 2016, Econjournals. All rights reserved.The relevance of the research problem is reasoned by global use of Internet technologies, altering the forms of personal self-identification: Atransition of the external world and human individuality in a digital code, the creation of informational imprint in space of the worldwide web, the alienation of the student youth in society, the substitution of reality by virtual world. In this direction a significant potential belongs to humanities, studying of which contributes to the interpenetration and mutual reinforcement of students’ social and virtual identification based on universal norms, values, value orientations, correction of virtual identity redundancy in real society. This article is aimed at scientifically-methodical substantiation of structure and content of pedagogical correction of higher school students’ self-identification in the process of humanities’ study. The leading method in this problem study is a method of modeling of the structure and content of students’ self-identification pedagogical correction in the process of humanitarian disciplines’ study. The article presents the theoretical and methodological foundations of the design and implementation of student’s social and virtual identity correction’s model, its discursive content and mechanisms, structure and new forms’ content in the process of humanities’ study. The presented materials in the article contribute to evidence-based correction of students virtual and social identity in the process of humanities’ study and are recommended to use for teachers, methodologists, university information departments’ programmers, improvement of qualification and teacher retraining courses’ attendants
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