3,707 research outputs found
Unsteady drag on a cylinder due to transverse oscillation at finite amplitude
No full textTransverse oscillations of a cylinder in a viscous fluid generate a force on the fluid that becomes non-linear at large oscillation amplitudes. When the cylinder motion is sinusoidal, non-linearity produces odd order harmonic distortion in the force. Numerical simulations based on the incompressible Navier–Stokes equations are used to explore (1) departures from linear theory and (2) the approach to quasi-steady behaviour, for oscillations over a wide frequency range at peak Reynolds numbers between 10-2 and 10. Non-linearity appears once the displacement amplitude becomes comparable with the viscous penetration depth at the oscillation frequency. The results provide insight into the attenuation of sound in air-filled fibrous materials, where non-linear behaviour has been observed at sound pressure levels around 150 dB and upwards (see the paper by H.L. Kuntz and D.T. Blackstock 1987 Journal of the Acoustical Society of America 81, 1723–1731 [3])
Domain Names in Turkey
No full textTurkey faces both unique and common domain name regulatory issues. In this paper, the author focuses on the challenges ahead for Turkey, with especial focus on the regulation of IDNs
Plagiarism: concepts and contexts
No full textAfter outlining the key difficulties in modern literature on academic plaigarism, the author suggests that these may be resolved by a new model of plaigarism (whilst noting that this new model does raise additional uncertainties, e.g. as to the status of 'self plagiarism') that she has developed
Dictionary of Acoustics
No full textThe science and technology of acoustics embraces an unusually wide range of disciplines, from aircraft noise reduction to ultrasonics in medicine, from psychoacoustics to signal processing. The student of acoustics has to become familiar with a corresponding range of specialist terms in order to communicate with others and to understand the literature. Here, in one informative dictionary, for the first time, are listed accurate and helpful definitions to provide the student - or the specialist from another discipline - with a point of entry into the world of acoustics. The dictionary's 2,800 entries cover most of the essential concepts and terminology that the practicing acoustician needs to understand, outside the subfields of music and speech communication. The author has drawn on experience gained during a long career spent mostly at Southampton University's multidisciplinary Institute of Sound and Vibration Research, supplemented by the expertise and perspective of a team of subject specialists
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
Applications of generalized Ky Fan's matching theorem in minimax and variational inequality
No full textWe present some application of the generalized Ky Fan's Matching Theorem stated by Chebbi, Gourdel and Hammami in minimax and variational inequalities using a generalized coercivity type condition for correspondences defined in L-space.L-structures, L-spaces, L-KKM correspondences, L-coercing family, minimax and variational inequalities.
Modelling of turbulent jets and wall layers: extensions of Lighthill's acoustic analogy with application to computational aeroacoustics
No full textTwo extensions to Lighthill’s aeroacoustic analogy are presented. First, equivalent sources due to initial conditions are derived that supplement those due to boundary conditions, as given by Ffowcs Williams & Hawkings. The resulting exact inhomogeneous wave equation is then reformulated with pressure rather than density as the wave variable, and the right-hand side is rearranged using the energy equation with no additional assumptions. Applications to computational aeroacoustics are discussed, and illustrated with examples based on 2D and 3D simulations
Coauthor prediction for junior researchers
No full textResearch collaboration can bring in different perspectives and generate more productive results. However, finding an appropriate collaborator can be difficult due to the lacking of sufficient information. Link prediction is a related technique for collaborator discovery; but its focus has been mostly on the core authors who have relatively more publications. We argue that junior researchers actually need more help in finding collaborators. Thus, in this paper, we focus on coauthor prediction for junior researchers. Most of the previous works on coauthor prediction considered global network feature and local network feature separately, or tried to combine local network feature and content feature. But we found a significant improvement by simply combing local network feature and global network feature. We further developed a regularization based approach to incorporate multiple features simultaneously. Experimental results demonstrated that this approach outperformed the simple linear combination of multiple features. We further showed that content features, which were proved to be useful in link prediction, can be easily integrated into our regularization approach. © 2013 Springer-Verlag
Surface and mechanical characterization of TaN-Ag nanocomposite thin films
No full textTaN-Ag nanocomposite thin films with Ag nano-particles dispersed in TaN matrix and surface were prepared by reactive co-sputtering of Ta and Ag in the plasma of N-2 and At. After deposition, the films were annealed using RTA (Rapid Thermal Annealing) at 350 degrees C for 2, 4, 8 min respectively to induce the nucleation and growth of Ag particles. C-AFM (Conductive-atomic Force Microscopy) and SSPM (Surface Scanning Potential Microscopy) were applied to characterize the emergence of Ag nano-particles on the surface of TaN-Ag thin films in this study. It is seen that Ag nano-particles may emerge in the matrix and on the surface of TaN and, possibly, grow. The results are compared with that obtained by FE-SEM (field-emission scanning electron microscopy). After comparison, C-AFM and SSPM are seen to be useful in characterizing the emergence and distribution of Ag particles. The results also show that the films' hardness and Young's modulus values would increase or decrease with the increase of annealing time, depending on Ag content and annealing time. This behavior is similar to that of TaN-Cu nanocomposite film. In addition, the increase of wear resistance of these coatings is proved. (c) 2007 Elsevier B.V. All rights reserved
Mass limits of charged Higgs boson at large tan from e+e- annihilations at s=50-60.8 GeV
No full textA search for the pair production of charged Higgs particles decaying via the H- mode has been made in e+e- annihilations at center-of-mass energies between 50 and 60.8 GeV using the AMY detector at the KEK collider TRISTAN. No evidence for their existence is observed and 95%-C.L. mass limits are presented. The result has been interpreted in terms of the tan parameter in the Higgs sector. © 1990 The American Physical Society
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