26,184 research outputs found
Stability of oscillatory gravity wave trains with energy dissipation and Benjamin-Feir instability
No full textThe Benjamin-Feir instability describes the instability of a uniform oscillatory wave train in an irrotational flow subject to small perturbation of wave number, amplitude and frequency. Their instability analysis is based on the perturbation around the second order Stokes wave which satisfies the dynamic and kinematic free-surface boundary conditions up to the second order. In the same irrotational flow and perturbation framework of the Benjamin-Feir analysis, the perturbation in the present paper is around a nonlinear oscillatorywave train which solves exactly the dynamic free-surface boundary conditionand satisfies the kinematic free-surface boundary condition up to the third or-der. It is shown that the nonlinear oscillatory wave train is stable with respectto the perturbation when the irrotational flow involves small Rayleigh energydissipation
Control and Filtering for Discrete Linear Repetitive Processes with H infty and ell 2--ell infty Performance
No full textRepetitive processes are characterized by a series of sweeps, termed passes, through a set of dynamics defined over a finite duration known as the pass length. On each pass an output, termed the pass profile, is produced which acts as a forcing function on, and hence contributes to, the dynamics of the next pass profile. This can lead to oscillations which increase in amplitude in the pass to pass direction and cannot be controlled by standard control laws. Here we give new results on the design of physically based control laws for the sub-class of so-called discrete linear repetitive processes which arise in applications areas such as iterative learning control. The main contribution is to show how control law design can be undertaken within the framework of a general robust filtering problem with guaranteed levels of performance. In particular, we develop algorithms for the design of an H? and dynamic output feedback controller and filter which guarantees that the resulting controlled (filtering error) process, respectively, is stable along the pass and has prescribed disturbance attenuation performance as measured by and – norms
Other title: ODOT Research Executive Summary Report : State Job Number: 134696
No full textTitle from caption.; "Researchers: Benjamin Coifman, Bo Huang, Keith Redmill, Mo Wu"--Page 1.; "Report Publication Date: January 2015"--Page 1.; "FHWA Report Number: FHWA/OH-2015/1"--Page 1.; Harvested from the web on 4/13/1
Hakubutsu shinpen : kanban /
No full textSpecial collection from London Missionary Society.; On double leaves, oriental style (fukurotoji).; 880-07 "Rosokan hatsuda" -- at the back of rear cover.; 880-04 Daisanshu, Chinshudo dosen.; Yogakushi jiten, p. 563 (Hakubutsu shinpen, 3-satsu, by Goshin (Benjamin Hobson); written in Chinese).; Also available in an electronic version via the Internet at http://nla.gov.au/nla.gen-vn2059320.880-06 Bo wu xin bian. Japanese & Chinese.Hakubutsu shinpen.Kanban hakubutsu shinpen
Acoustic radiation due to scattering of T-S wave by the mean-flow distortion induced by steady local suction
No full textSubstantial sound waves can be generated by boundary-layer instability modes when the latter are scattered by a rapid mean-flow distortion. This is a rather generic mechanism and operates when an oncoming T-S wave is scattered by a steady local suction slot. This paper focuses on this problem by extending a recently developed Local Scattering Theory (Wu & Dong, J. Fluid Mech. submitted), where a so-called transmission coefficient, defined as the ratio of the T-S wave amplitude downstream of the scatter to that upstream, is introduced to characterize the effect of a local scatter on boundary-layer instability and transition. As in the earlier work, the mathematical formulation is based on triple-deck formulism, but in order to accommodate the acoustic far field, which was not considered in the paper mentioned, the unsteady terms in the upper deck, which play a leading-order role in radiation, are retained, and the influence of the radiated sound on the near-wall perturbation is included. The upper deck equation for the pressure is the Helmholtz equation rather than the Laplace equation. This leads to a modified pressure-displacement relation, which is coupled with the linearized boundary-layer equations in the lower deck. Discretization of the whole system formulates a generalized eigenvalue problem, which is solved numerically. It is found that suction suppresses oncoming T-S waves, and this effect increases with the suction velocity and the slot width. The directivity is ndependent of the flow parameters only when the Mach number is low. The intensity of the radiated sound in general increases with the frequency, the suction velocity and the width of the suction slot. Interestingly, for O(1) suction velocities, the radiated sound is very weak, indicating that the gain of stabilizing effect does not cause aeroacoustic penalty
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sj-pdf-1-smm-10.1177_09622802221133556 - Supplemental material for An overview of propensity score matching methods for clustered data
No full textSupplemental material, sj-pdf-1-smm-10.1177_09622802221133556 for An overview of propensity score matching methods for clustered data by Benjamin Langworthy, Yujie Wu and Molin Wang in Statistical Methods in Medical Research</p
Yidali xian dai wen xue.
No full textBenjamin Crémieux 著 ; 董家濚譯.Benjamin Crémieux zhu ; Dong Jiaxing yi
Measurement of dwell times of spin polarized rubidium atoms on octadecyltrichlorosilane- and paraffin-coated surfaces
No full textWe report the measurement of dwell times of spin polarized Rb atoms on octadecyltrichlorosilane OTS- and paraffin-coated surfaces. We find that at a cell temperature of 72 °C the dwell times for OTS- and paraffin-coated surfaces are 0.9+-0.1 microsecond and 1.8 +-0.2 microsecond , respectively. Since the relaxation probability on paraffin is almost one order of magnitude smaller than that on OTS, the longer dwell time for paraffin indicates that the average strength of the interactions experienced by Rb atoms while they are inside paraffin is much weaker than while they are inside OTS.Peer reviewe
Felix Wu Appointed Vice Dean
No full textFelix Wu, Professor of Law and Faculty Director of the Cardozo Data Law Initiative (CDLI), has been named Vice Dean of Cardozo School of Law.https://larc.cardozo.yu.edu/cardozo-news-2023/1027/thumbnail.jp
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