2,904,410 research outputs found
Automatic integral reduction for higher order perturbative calculations
Contains fulltext :
60133.pdf (Author’s version preprint ) (Open Access)We present a program for the reduction of large systems of integrals to master integrals. The algorithm was first proposed by Laporta; in this paper, we implement it in MAPLE. We also develop two new features which keep the size of intermediate expressions relatively small throughout the calculation. The program requires modest input information from the user and can be used for generic calculations in perturbation theory
Surface profile measurement using spatially dispersed short coherence interferometry
Improved online techniques for surface profile measurement can be beneficial in many high/ultra-precision manufacturing in terms of enabling manufacture and reducing costs. This paper introduces a spatially dispersed short-coherence interferometer sourced by a SLD (Super Luminescent Diode). This technique uses a broadband light source which is spatially dispersed across a surface using a reflective grating and a scan lens. In this way, the phase data pertaining to surface at height is spectrally encoded. The light reflected from the surface is interfered with a reference beam in a Michelson interferometer after which the resulting fringes are interrogated by a spectrometer. Phase shifting interferometry is used to extract the spectrally encoded phase information by analysing four captured frames using a Carré algorithm procedure and in this way surface height can be determined across a profile on a sample. The short coherent light utilised in this interferometric technique means it has potential for application as a remote probe through an optical fibre link. This paper describes the concept of a spatially dispersed short coherence interferometer and provides some initial experimental results
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Skin friction factor and mean velocity profile measured in high-reynolds-number turbulent pipe flow
A friction factor in a fully developed pipe flow is measured very accurately over wide range Reynolds number from 103 to 107 at the high Reynolds number facility in AIST,NMIJ. Also a velocity profile is measured by using a LDV up to 106. From the comparison between a velocity profile and the friction factor, we found that a log-law profile is well observed and Kármán constant is estimated to be 0.385. Based on the measurements, we present a new functional form of the friction factor which is consistent with mean velocity profile
Kari Stefánsson: a general of genetics
profile; biographyhttp://dx.doi.org/10.1016/S0140-6736(07)60133-
Going Beyond Counting First Authors in Author Co-citation Analysis
The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Usability of Analytical Methods in Design of Instrument Profile of Screw Type Compressors
A very important catch, not only in the engineering, but also in any industry of production of national
economy in general, takes the use of compressed air. Enlargening of industrial production volumes, parallel asks for larger demand of compressed air, for getting them more frequently use technologically most fashionable, economic and the safest of compressors machines - including screw types compressors. Geometry of screw type compressor shaft isn’t evolvent type, whereof is dependent compressor action productivity. For creating screw type shaft profile there is necessity to make special designed instrument with which assistance are available reach right forms of profile contours. In the beginning of this article is provided instrument designing possibilities examination, what operates with knock dawn method. In foundation there are examined three possible of calculation methods of instrument profile type: graphical, analytical and graphical analytical method. Also provide analysis of these methods usability in modern production. At the second part of work is given an analytical calculation of disevolvent instrument profile type, conformable the type of rotors of screw type
compressors. At the end of article conclusion is done usability analysis of profile designing methods
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