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    Precise CCD image analysis for planar laser-induced fluorescence experiments

    , Article Optics and Laser Technology ; Volume 38, Issue 3 , 2006 , Pages 152-161 ; 00303992 (ISSN) Golnabi, H ; Sharif University of Technology
    2006
    Abstract
    The goal of this paper is to describe essential criteria for image analysis of planar laser-induced fluorescence (PLIF) signals. A new image file conversion method is introduced and some typical illustrative examples showing the potential applications of the method in PLIF experiments are presented. Analysis of row, column, and total pixel counts, and the dark noise related to an image are discussed. Image segmentation, averaging and background correction can be easily done by the reported method. In our analysis it is straightforward to inspect the pixel counts and check for saturation of the camera sensors. It is also feasible to obtain a particular row or column for interpretation and it... 

    Development of a computer program for calculation of the alpha parameter in the linear amplitude sweep test and comparison with rheological parameters

    , Article Transportation Research Record ; Volume 2674, Issue 7 , 2020 , Pages 284-298 Abdollahi, S. F ; Farrokhi, M ; Tabatabaee, N ; Sharif University of Technology
    SAGE Publications Ltd  2020
    Abstract
    Characterizing and modeling the fatigue performance of an asphalt binder is important when designing asphalt mixtures which can resist premature fatigue failure. Performance grading (PG) standards include the fatigue factor (G*.sinδ) to evaluate the fatigue resistance of asphalt binders. This criterion seems to be inaccurate, especially when applied to modified asphalt binders. American Association of State Highway and Transportation Officials (AASHTO) TP 101 has been designed to evaluate the fatigue resistance of asphalt binders using Schapery’s work potential theory. The damage evolution rate (α parameter) is the key element of this method and is calculated from the rheological properties... 

    Phase noise degradation of varactor and BJT frequency multipliers in the presence of parametric instability

    , Article IET Microwaves, Antennas and Propagation ; Volume 4, Issue 3 , 2010 , Pages 408-419 ; 17518725 (ISSN) Ahmadi, A ; Banai, A ; Farzaneh, F ; Sharif University of Technology
    2010
    Abstract
    Varactor and bipolar junction transistor (BJT) frequency multipliers are a class of non-linear circuits that show parametric instability when the input drive is varied. If parametric oscillations are present in the circuit, output phase noise of the multiplier degrades remarkably in some specific driving levels. Phase noise analysis is performed by the conversion matrix method using generalised nodal analysis. The conversion method predicts the phase noise degradation precisely because it encompasses the effect of the noise sources that are modulated by the large signal drive. The added phase noise of a varactor and a BJT frequency doubler with subharmonic oscillation is calculated and the... 

    Effect of parametric instability on phase noise degradation in a varactor frequency multiplier

    , Article Asia-Pacific Microwave Conference, APMC 2007, Bangkok, 11 December 2007 through 14 December 2007 ; 2007 ; 1424407494 (ISBN); 9781424407491 (ISBN) Ahmadi, A ; Banai, A ; Sharif University of Technology
    2007
    Abstract
    Varactor frequency multipliers often show parametric instability with increasing RF input power. Examination of the added phase noise of the varactor frequency multipliers show that, if parametric oscillations are present in the circuit, output phase noise degrades remarkably in some specific driving levels. Phase noise analysis is done by the conversion matrix method. The conversion method predicts the phase noise degradation precisely because it encounters the noise conversion by large driving levels. The added phase noise of a varactor frequency doubler with subharmonic oscillation is calculated and the simulation results are compared with measurement results. Both simulation and...