Results 231 to 240 of about 1,908,810 (282)
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A Doppler system for dynamic vector velocity maps
Ultrasound in Medicine and Biology, 2002The aim of the vector Doppler technique is the quantitative reconstruction of a velocity field independently of the ultrasonic probe axis to flow angle. In particular, vector Doppler is interesting for studying vascular pathologies related to complex blood flows.
Lorenzo Capineri, Leonardo Masotti
exaly +4 more sources
Introduction to vector velocity imaging
, 2010 Current ultrasound scanners can only estimate the velocity along the ultrasound beam and this gives rise to the cos() factor on all velocity estimates. This is a major limitation as most vessels are close to perpendicular to the beam. Also the angle varies as a function of space and time making it virtually impossible to compensate for the factor and ...
Jensen, Jørgen Arendt; id_orcid 0000-0002-7896-3136 +3 more
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2D velocity vector profile measurement on bubbly flow using ultrasonic technique
Mechanical Engineering Journal, 2020 This paper describes a measurement technique for a two-dimensional (2D) velocity vector profile in the two-phase bubbly flow. The Ultrasonic Velocity Profiler (UVP) method, which is a nonintrusive technique applicable for real-time measurement, is ...
Hideharu Takahashi +2 more
exaly +3 more sources
A new method for estimation of velocity vectors
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1998The paper describes a new method for determining the velocity vector of a remotely sensed object using either sound or electromagnetic radiation. The movement of the object is determined from a field with spatial oscillations in both the axial direction of the transducer and in one or two directions transverse to the axial direction.
J A, Jensen, P, Munk
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Pulse centroid velocity of the Poynting vector
Journal of the Optical Society of America A, 2004The evolution of the pulse centroid velocity of the Poynting vector for both ultrawideband rectangular and ultrashort Gaussian envelope pulses is presented as a function of the propagation distance in a dispersive, absorptive dielectric material. The index of refraction of the material is described by the Lorentz-Lorenz formula in which a single ...
Natalie A, Cartwright, Kurt E, Oughstun
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High Angle of Attack Velocity Vector Rolls
IFAC Proceedings Volumes, 1994Abstract This paper presents the design of a flight control system for performing the velocity vector roll maneuver at high angles of attack. A six degree of freedom model is developed, and the multiple-input multiple-output Quantitative Feedback Theory (QFT) robust control design method is used to treat both the inherent system nonlinearities and ...
K.E. Boyum, M. Pachter, C.H. Houpis
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The Mathematical Gazette, 1969
In many books on elementary mechanics, it is assumed that velocity is a vector quantity on the grounds that it has magnitude and direction. It is, however, very far from obvious that these are sufficient reasons and a rather more thorough investigation of the nature of velocity may provide not only a clearer idea of what velocity is but may also clear ...
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In many books on elementary mechanics, it is assumed that velocity is a vector quantity on the grounds that it has magnitude and direction. It is, however, very far from obvious that these are sufficient reasons and a rather more thorough investigation of the nature of velocity may provide not only a clearer idea of what velocity is but may also clear ...
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Rigid velocities compatible with five image velocity vectors
Image and Vision Computing, 1989Abstract The problem of obtaining rigid velocities compatible with a given set of image velocity vectors is algebraic in that it depends on the solution of simultaneous polynomial equations. We show that five image velocity vectors yield two quartic polynomial constraints on the translational part of the rigid velocity, and that of the 16 common ...
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Guidance, Navigation, and Control Conference, 1996
This paper is devoted to the challenging problem of high angle of attack and maneuvering flight control, with special emphasis on the critical velocity vector roll maneuver. The development of a flight control system for maneuvering flight, i.e., high amplitude maneuvers, requires careful modeling.
M. Pachter, P. Chandler
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This paper is devoted to the challenging problem of high angle of attack and maneuvering flight control, with special emphasis on the critical velocity vector roll maneuver. The development of a flight control system for maneuvering flight, i.e., high amplitude maneuvers, requires careful modeling.
M. Pachter, P. Chandler
openaire +1 more source