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Journal articles on the topic 'Velocity triangles'

Author: Grafiati

Published: 4 June 2021

Last updated: 4 February 2022

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1

Rüger, Andreas, and Dave Hale. "Meshing for velocity modeling and ray tracing in complex velocity fields." GEOPHYSICS 71, no. 1 (2006): U1—U11. http://dx.doi.org/10.1190/1.2159061.

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In seismic processing, velocity fields are commonly represented on finely sampled Cartesian grids. Attractive alternatives are unstructured grids such as meshes composed of triangles or tetrahedra. Meshes provide a space-filling framework that enables editing of velocity models while facilitating numerical tasks such as seismic modeling and inversion. In this paper, we introduce an automated process to generate meshes of subsurface velocity structures for highly resolved velocity fields without providing additional external constraints such as horizons and faults. Our analysis shows that these

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2

Avitzur, B., W. Gordon, and S. Talbert. "Analysis of Strip Rolling by the Upper Bound Approach." Journal of Engineering for Industry 109, no. 4 (1987): 338–46. http://dx.doi.org/10.1115/1.3187137.

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The process of strip rolling is analyzed using the upper bound technique. Two triangular velocity fields, one with triangles in linear rigid body motion and the other with triangles in rotational rigid body motion, are developed. The total power is determined as a function of the four independent process parameters (relative thickness, reduction, friction and net front-back tension). The results of these two velocity fields are compared with the established solution from Avitzur’s velocity field of continuous deformation. Upon establishing the validity of the triangular velocity field as an ap

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3

Gu, Yun Qing, Jing Ru, Zhao Gang, Zhao Yuan Li, Wen Bo Liu, and Muhammad Farid Khattak. "Influence of Jet Hole Configuration on Drag Reduction of Bionic Jet Surface." Applied Mechanics and Materials 461 (November 2013): 725–30. http://dx.doi.org/10.4028/www.scientific.net/amm.461.725.

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According to the jet hole configuration mode of bionic jet surface and its influence on the drag reduction, as the basic form of jet hole configuration is the isosceles triangle elements, so this was used to establish the computational model of jet hole configuration. In this case, the height and base of the triangles were considered as variable. The SST k-ω turbulence model was used to simulate and research the drag reduction characteristics of bionic jet surface in different configuration modes of jet holes at the main flow field velocity value of 20m/s and the jet velocity value of 0.4~2.0m

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4

Averbeck, Bruno B., Matthew V. Chafee, David A. Crowe, and Apostolos P. Georgopoulos. "Parietal Representation of Hand Velocity in a Copy Task." Journal of Neurophysiology 93, no. 1 (2005): 508–18. http://dx.doi.org/10.1152/jn.00357.2004.

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We recorded neural activity from ensembles of neurons in areas 5 and 2 of parietal cortex, while two monkeys copied triangles, squares, trapezoids, and inverted triangles and used both linear and nonlinear models to predict the hand velocity from the neural activity of the ensembles. The linear model generally outperformed the nonlinear model, suggesting a reasonably linear relation between the neural activity and the hand velocity. We also found that the average transfer function of the linear model fit to individual cells was a low-pass filter because the neural response had considerable hig

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5

Pennock, Gordon R., and Patrick J. Meehan. "Geometric Insight Into the Dynamics of a Rigid Body Using the Spatial Triangle of Screws." Journal of Mechanical Design 124, no. 4 (2002): 684–89. http://dx.doi.org/10.1115/1.1500340.

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Geometric relationships between the velocity screw and momentum screw are presented, and the dual angle between these two screws is shown to provide important insight into the kinetics of a rigid body. Then the centripetal screw is defined, and the significance of this screw in a study of the dynamics of a rigid body is explained. The dual-Euler equation, which is the dual form of the Newton-Euler equations of motion, is shown to be a spatial triangle. The vertices of the triangle are the centripetal screw, the time rate of change of momentum screw, and the force screw. The sides of the triang

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6

Selzer, Philipp, and Olaf A. Cirpka. "Postprocessing of standard finite element velocity fields for accurate particle tracking applied to groundwater flow." Computational Geosciences 24, no. 4 (2020): 1605–24. http://dx.doi.org/10.1007/s10596-020-09969-y.

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Abstract Particle tracking is a computationally advantageous and fast scheme to determine travel times and trajectories in subsurface hydrology. Accurate particle tracking requires element-wise mass-conservative, conforming velocity fields. This condition is not fulfilled by the standard linear Galerkin finite element method (FEM). We present a projection, which maps a non-conforming, element-wise given velocity field, computed on triangles and tetrahedra, onto a conforming velocity field in lowest-order Raviart-Thomas-Nédélec ($\mathcal {RTN}_{0}$ R T N 0 ) space, which meets the requirements

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7

Liebold, Frank, Ali A. Heravi, Oliver Mosig, Manfred Curbach, Viktor Mechtcherine, and Hans-Gerd Maas. "Crack Propagation Velocity Determination by High-speed Camera Image Sequence Processing." Materials 13, no. 19 (2020): 4415. http://dx.doi.org/10.3390/ma13194415.

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The determination of crack propagation velocities can provide valuable information for a better understanding of damage processes of concrete. The spatio-temporal analysis of crack patterns developing at a speed of several hundred meters per second is a rather challenging task. In the paper, a photogrammetric procedure for the determination of crack propagation velocities in concrete specimens using high-speed camera image sequences is presented. A cascaded image sequence processing which starts with the computation of displacement vector fields for a dense pattern of points on the specimen’s

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8

Xing, Weiwei, Jian Zhang, Wei Lu, and Peng Bao. "An Improved Potential Field Based Method for Crowd Simulation." International Journal of Software Engineering and Knowledge Engineering 25, no. 03 (2015): 427–51. http://dx.doi.org/10.1142/s021819401540015x.

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Crowd simulation explores crowd behavior in virtual environments, which has been extensively studied in many areas, such as safety and civil engineering, transportation, social science, and entertainment industry. In this paper, an improved potential field method is proposed to achieve the real-time crowd simulation, which is composed of the global navigation with Dijkstra's algorithm and the potential field based local navigation. First, a region separation is performed to divide the environment into a set of triangles, and thus a topological graph can be built with the triangles as vertices.

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9

MULDER, W. A. "HIGHER-ORDER MASS-LUMPED FINITE ELEMENTS FOR THE WAVE EQUATION." Journal of Computational Acoustics 09, no. 02 (2001): 671–80. http://dx.doi.org/10.1142/s0218396x0100067x.

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The finite-element method (FEM) with mass lumping is an efficient scheme for modeling seismic wave propagation in the subsurface, especially in the presence of sharp velocity contrasts and rough topography. A number of numerical simulations for triangles are presented to illustrate the strength of the method. A comparison to the finite-difference method shows that the added complexity of the FEM is amply compensated by its superior accuracy, making the FEM the more efficient approach.

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10

Monen, Jos, and Eli Brenner. "Detecting Changes in One's Own Velocity from the Optic Flow." Perception 23, no. 6 (1994): 681–90. http://dx.doi.org/10.1068/p230681.

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Experiments were designed to establish whether we can use the optic flow to detect changes in our own velocity. Subjects were presented with simulations of forward motion across a flat surface. They were asked to respond as quickly as possible to a step increase in simulated ego-velocity. The smallest change for which subjects could respond within 500 ms was determined. At realistic simulated speeds of locomotion, the simulated ego-velocity had to increase by about 50%. The threshold for detecting changes in simulated ego-velocity was hardly better than the threshold for detecting other change

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11

Yang, Er Long, Yu Xin Gao, and Dong Liang Li. "The Research of the Seepage Regularity of Power-Law Fluid under Porosity Scale." Applied Mechanics and Materials 423-426 (September 2013): 1722–26. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1722.

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There are various shapes of capillary tubes in the rock, and the flow in triangles and rectangles capillary tubes has been studied very little. In this paper, the approximate solution of the distribution of the velocity in triangles capillary tubes has been obtained using variational method. The quantitative relation between pressure difference and flow rate in the two kinds of capillary tubes has been obtained by integrating in the entire capillary tubes, which is similar to Poiseuille's law. this study also applies the Pdetool tool in Matlab to solve the laminar flow of different sections in

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12

Cader, T., O. Masbernat, and M. C. Roco. "Two-Phase Velocity Distributions and Overall Performance of a Centrifugal Slurry Pump." Journal of Fluids Engineering 116, no. 2 (1994): 316–23. http://dx.doi.org/10.1115/1.2910274.

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Back-scattering LDV has been used to investigate particulate two-phase flow in a centrifugal slurry pump. The measurements reported here have been made with a dilute suspension of 0.8 mm glass beads at the impeller-casing flow interface. This interface is of practical importance because the corresponding velocity and concentration results can be used to determine the pump head and flowrate. The present study evaluates the connection between the liquid and solids velocity distribution measured around the impeller and the pump performance determined from measurements at the pump inlet and outlet

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13

Li, Wen-Guang. "Effects of Flow Rate and Viscosity on Slip Factor of Centrifugal Pump Handling Viscous Oils." International Journal of Rotating Machinery 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/317473.

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Slip factor is an important parameter in the hydraulic design of centrifugal pump impeller for handling viscous oils. How to extract the factor from CFD computational results and how flow rate and liquid viscosity to affect it remain unclear. In the present paper, the flip factor was estimated by means of two approaches: one is from the velocity triangles at the impeller outlet and the other is due to the impeller theoretical head of 3D turbulent viscous fluid. The velocity of water and viscous oils in the impeller and volute computed by CFD was validated with LDV measurements at the best effi

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14

Chang, C. C. "Crossed patch arrangements of linear triangular elements for upper bound finite-element analysis of plane strain deformation problems." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 2 (2010): 280–91. http://dx.doi.org/10.1243/09544062jmes2072.

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In standard linear finite-element formulations, volumetric locking because of the incompressibility constraint that may occur in computational plasticity is often encountered. This study uses crossed patch arrangements of triangles to form quadrilateral elements in order to overcome the locking in the upper bound finite-element analysis of plane strain deformation problems. The velocity field is described in terms of linear triangular elements, while the incompressibility constraint is imposed by quadrilateral elements. Rigid, perfectly plastic materials, and strain hardening materials that fo

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15

Yang, Yuande, Bo Sun, Zemin Wang, et al. "GPS-derived velocity and strain fields around Dome Argus, Antarctica." Journal of Glaciology 60, no. 222 (2014): 735–42. http://dx.doi.org/10.3189/2014jog14j078.

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AbstractKnowledge of the surface topography, velocity field and strain field at an ice-core site is critical to the accurate interpretation of ice-core records. At Dome Argus (Dome A), where a Chinese deep ice-core drilling project is being carried out, we have produced an accurate surface digital elevation model from GPS measurements in January 2013 at 47 sites. We identify two peaks at Dome A, with the northern peak ~7 cm higher than the southern peak. Repeat GPS measurements at 12 sites in 2008 and 2013 provide a surface velocity field around the dome. The surface velocity ranges from 3.1±2

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16

Joachim, Kurzke. "Turbine Map Extension - Theoretical Considerations and Practical Advice." Journal of the Global Power and Propulsion Society 4 (November 26, 2020): 176–89. http://dx.doi.org/10.33737/jgpps/128465.

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Physically sound compressor and turbine maps are the key to accurate aircraft engine performance simulations. Usually, maps only cover the speed range between idle and full power. Simulation of starting, windmilling and re-light requires maps with sub-idle speeds as well as pressure ratios less than unity. Engineers outside industry, universities and research facilities may not have access to the measured rig data or the geometrical data needed for CFD calculations. Whilst research has been made into low speed behavior of turbines, little has been published and no advice is available on how to

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17

SCHÖTZAU, DOMINIK, and CHRISTOPH SCHWAB. "MIXED hp-FEM ON ANISOTROPIC MESHES." Mathematical Models and Methods in Applied Sciences 08, no. 05 (1998): 787–820. http://dx.doi.org/10.1142/s0218202598000366.

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Mixed hp-FEM for incompressible fluid flow on anisotropic meshes are analyzed. A discrete inf–sup condition is proved with a constant independent of the meshwidth and the aspect ratio. For each polynomial degree k≥2 we present velocity-pressure subspace pairs which are stable on quadrilateral mesh-patches independently of the element aspect ratio, implying in particular divergence stability on the so-called Shishkin-meshes. Moreover, the inf–sup constant is shown to depend on the spectral order k like k-1/2 for quadrilateral meshes and like k-3 for meshes containing triangles. New consistency

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18

Hesketh, J. A., and P. J. Walker. "Effects of Wetness in Steam Turbines." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 219, no. 12 (2005): 1301–14. http://dx.doi.org/10.1243/095440605x32110.

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Courses in mechanical engineering usually introduce the theory of axial-flow turbo-machines in terms of simple velocity triangles representing the bulk flow of ideal compressible fluid through the blade passages. A distinctive practical difference, peculiar to steam turbines (ST), is the presence of liquid-water in the flow field. The steam wetness in such turbines is widely known to be doubly-damaging, leading to both loss of efficiency and to mechanical damage (erosion, etc.) of the machine components. Over recent decades, a whole new field of mechanical engineering science has evolved on th

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19

Du, Wenhai, and Olivier Léonard. "Numerical Simulation of Surge in Axial Compressor." International Journal of Rotating Machinery 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/164831.

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The object of this paper is to provide a reliable tool to simulate the stationary and transient operation performances in multistage axial compression systems, especially poststall behavior. An adapted version of the 1D Euler equations with additional source terms is solved by a time marching and control volume method. The equations are discretized at midspan both inside the blade rows and the nonbladed regions, along the real flow path geometry. The source terms express the blade-flow interactions and are estimated by calculating the velocity triangles for each blade row. Loss coefficient and

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20

Tisserant, D., and F. A. E. Breugelmans. "Rotor Blade-to-Blade Measurements Using Particle Image Velocimetry." Journal of Turbomachinery 119, no. 2 (1997): 176–81. http://dx.doi.org/10.1115/1.2841096.

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The study of turbomachinery flow fields requires detailed experimental data. The rotating parts of turbomachines greatly limit the measurement techniques that can be used. Particle Image Velocimetry (PIV) appears to be a suitable tool to investigate the blade-to-blade flow in a rotor. The facility is a subsonic axial-flow compressor. The experimental apparatus enables the recording of a double-exposed photograph in a circumferential plane located at 85 percent of the blade height. The illumination plane has an axial direction and is provided by a pulsed ruby laser. The tracers used are submicr

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21

Zhang, Z. H., Z. J. Yang, and J. H. Li. "An Adaptive Polygonal Scaled Boundary Finite Element Method for Elastodynamics." International Journal of Computational Methods 13, no. 02 (2016): 1640015. http://dx.doi.org/10.1142/s0219876216400156.

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An adaptive polygonal scaled boundary finite element method (APSBFEM) is developed for elastodynamics. Flexible polygonal meshes are generated from background Delaunay triangular meshes and used to calculate structure’s dynamic responses. In each time step, a posteriori-type energy error estimator is employed to locate the polygonal subdomains with exceeding spatial discretization error, then edge midpoints of the corresponding triangles are inserted into the background. A new Delaunay triangular mesh and a polygonal mesh are regenerated successively. The state variables, including displacemen

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22

Wu, Cheng-Feng, and Huey-Chu Huang. "Detection of a fracture zone using microtremor array measurement." GEOPHYSICS 84, no. 1 (2019): B33—B40. http://dx.doi.org/10.1190/geo2017-0393.1.

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We have conducted microtremor array measurements to estimate shallow S-wave velocity ([Formula: see text]) structures at two sites (the 921 Earthquake Museum of Taiwan and the Taiwan Provincial Consultative Council) located near surface ruptures of the Chelungpu Fault. Ten stations, consisting of three different-aperture triangles and a central station, are adopted for each array deployment. Using the array data, we calculate dispersion curves of Rayleigh waves using the frequency-wavenumber spectrum method and then estimate [Formula: see text] structures by the surface-wave inversion techniqu

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23

Worley, Shelby C. "The geometry of reflection." GEOPHYSICS 58, no. 2 (1993): 293–97. http://dx.doi.org/10.1190/1.1443413.

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The two‐dimensional (2-D) reflection path from a dipping plane between an offset source‐receiver combination in a constant velocity medium can be described with several parameters (coordinates, offsets, angles, and lengths). Although there are many parameters, only four independent ones are needed to locally determine the reflection geometry. Given four determining parameters, the evaluations of other ones present problems that range from trivial to formidable. The circumscribed circle about the source, receiver, and specular point turns out to have a number of remarkable properties that are u

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24

KANG, HYUNG SUK, DUANE DENNIS, and CHARLES MENEVEAU. "FLOW OVER FRACTALS: DRAG FORCES AND NEAR WAKES." Fractals 19, no. 04 (2011): 387–99. http://dx.doi.org/10.1142/s0218348x1100549x.

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An experimental study of interactions between a high Reynolds number fluid flow and multi-scale, fractal, objects is performed. Studying such interactions is required to improve our current understanding of wind or ocean current effects on vegetation elements, which often display fractal-like branching geometries. The main objectives of the study are to investigate the effects of the range of scales (generation numbers) of the fractal object and of the incoming flow condition on the drag force and drag coefficient, and to observe flow features in the near wake region resulting from the interac

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25

Vinje, Vetle, Ketil Åstebøl, Einar Iversen, and Håvar Gjøystdal. "3-D ray modeling by wavefront construction in open models." GEOPHYSICS 64, no. 6 (1999): 1912–19. http://dx.doi.org/10.1190/1.1444697.

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A synthesis of two newly developed concepts in 3-D modeling is developed in this paper: (1) The open, (noncomplete) seismic model, and (2) the ray tracing based wavefront (WF) construction method. The open model may contain interfaces with holes and other missing parts, which simplifies model building considerably because the input horizon data from standard interpretation and processing packages are often incomplete. A set of volumes is defined in the model. A volume is a logical unit that points to a set of property functions, e.g., P-velocity, S-velocity, and density. The properties are rep

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26

Arghir, Mihai, and Jean Fre^ne. "A Triangle Based Finite Volume Method for the Integration of Lubrication’s Incompressible Bulk Flow Equations." Journal of Tribology 123, no. 1 (2000): 118–24. http://dx.doi.org/10.1115/1.1326444.

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It is well known that for a reduced Reynolds number Re*=ρVH/μs˙H/L greater than unity, inertia forces have a dominant effect in the transport equations, thus rendering the classical lubrication equation inapplicable. The so called “bulk flow” system of equations is then the appropriate mathematical model for describing the flow in bearing and seals operating at Re*⩾1. The difficulty in integrating this system of equations is that one has to deal with coupled pressure and velocity fields. Analytic methods have a very narrow application range so a numerical method has been proposed by Launder an

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27

Zaher, M. A. "Approximate method for calculating the characteristics of a radial flow pump." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 215, no. 4 (2001): 295–316. http://dx.doi.org/10.1177/095440890121500404.

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Similarity in flow patterns between fans and pumps provides the possibility of suggesting an approximate method for calculating radial flow pump characteristics. The proposed method uses relations expressing the energy balance of real fluids. Calculations of velocity triangles are given for a flow ahead of an impeller operating in sections with half-output, recognized as an average value. The results followed the expression within blade theory for radial impellers. While the exit angle helps to understand the blade shape at the no-lift position, the impeller losses, on the other hand, are rela

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28

Moukalled, F., and A. Honein. "Computer-Aided Analysis of the Pelton Wheel." International Journal of Mechanical Engineering Education 23, no. 4 (1995): 297–314. http://dx.doi.org/10.1177/030641909502300403.

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This paper describes PELTON, a microcomputer-based, interactive, and menu-driven software package for use as an educational tool by mechanical and civil engineering students in studying the operation of the Pelton wheel. The program is written in the Pascal computer language and runs on IBM PC, or compatible, computers. The package can handle problems related to impulse turbines by solving for unknown variables through a complete set of equations covering the turbine installation. Model-prototype problems can be tackled through similarity laws. This facility is included to help analysing and m

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29

Moukalled, F., and A. Honein. "Computer-Aided Analysis of Hydraulic Reaction Turbines." International Journal of Mechanical Engineering Education 25, no. 2 (1997): 73–91. http://dx.doi.org/10.1177/030641909702500201.

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A microcomputer-based educational software package designed to help mechanical engineering students to understand hydraulic reaction turbines is described. The software is interactive, menu-driven, and easy-to-use, is written in the Pascal computer language, and runs on IBM PC, or compatible, computers. The program can handle radial, mixed, or axial flow turbine problems by solving for unknown variables through a complete set of equations covering the turbine installation. Using similarity laws, model-prototype problems or operation under different conditions can also be tackled. Furthermore,

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30

Claret, A. "Rotationally and tidally distorted compact stars." Astronomy & Astrophysics 648 (April 2021): A111. http://dx.doi.org/10.1051/0004-6361/202140489.

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Context. To the best of our knowledge, there are no specific calculations of gravity-darkening exponents for white dwarfs in the literature. On the other hand, the number of known eclipsing binaries whose components are tidally and/or rotationally distorted white dwarfs is increasing year on year. Aims. Our main objective is to present the first theoretical approaches to the problem of the distribution of temperatures on the surfaces of compact stars distorted by rotation and/or tides in order to compare with relevant observational data. Methods. We used two methods to calculate the gravity-da

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31

Кислицын, Степан Александрович, Константин Александрович Митин, and Владимир Степанович Бердников. "Numerical simulation of heat transfer processes during single crystal growth by the Bridgman - Stockbarger method in fixed and rotating crucibles." Вычислительные технологии, no. 1(26) (April 2, 2021): 21–32. http://dx.doi.org/10.25743/ict.2021.26.1.002.

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Численно методом конечных элементов исследованы процессы кристаллизации кремния в плоскодонных неподвижных и равномерно вращающихся графитовых цилиндрических тиглях в режимах сопряженного конвективного теплообмена. Процессы кристаллизации кремния изучены при фиксированной скорости опускания тигля в холодную зону и различных скоростях его вращения. Опускание тигля имитировалось перемещением точки излома в распределении температуры на внешней стороне стенок тигля. Точка излома - это граница перехода от нагретого до начальной температуры участка стенки к области с заданным градиентом температуры.

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32

Benhegouga, Islem, and Ce Yang. "Steady Air Injection Flow Control in Centrifugal Compressor." Applied Mechanics and Materials 138-139 (November 2011): 471–77. http://dx.doi.org/10.4028/www.scientific.net/amm.138-139.471.

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In the present work steady air injection upstream of the leading edge was used in a centrifugal compressor, Whose preliminary design of compressor injection systems can be modeled by a geometrical relationship between user-specified yaw angle and resulting blade incidence angle based on simple velocity triangles, the error between the best yaw angle obtained from this relationship and that obtained from numerical simulation is less than 3%. To reveal the mechanism, steady numerical simulations were performed on high pressure ratio centrifugal compressor rotor operated with a rotor tip speed of

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33

Jordal, Kristin, Olav Bollard, and Ake Klang. "Aspects of Cooled Gas Turbine Modeling for the Semi-Closed O2/CO2 Cycle With CO2 Capture." Journal of Engineering for Gas Turbines and Power 126, no. 3 (2004): 507–15. http://dx.doi.org/10.1115/1.1762908.

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In order to capture the behavior of the oxyfuel cycle operating with high combustor-outlet temperature, the impact of blade and vane cooling on cycle performance must be included in the thermodynamic model. As a basis for a future transient model, three thermodynamic models for the cooled gas turbine are described and compared. The first model, known previously from the literature, models expansion as a continuous process with simultaneous heat and work extraction. The second model is a simple stage-by-stage model and the third is a more detailed stage-by-stage model that includes velocity tri

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34

Xu, Chao, Bangrang Di, and Jianxin Wei. "A physical modeling study of seismic features of karst cave reservoirs in the Tarim Basin, China." GEOPHYSICS 81, no. 1 (2016): B31—B41. http://dx.doi.org/10.1190/geo2014-0548.1.

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On seismic migration sections, anomalous bright spots, called the string of beads response (SBR), are common features of carbonate karst reservoirs at the seismic scale in the Tarim Basin, China. To understand the SBR features of different karst caves, which is an important issue for local exploration, we conducted a physical modeling experiment. Within the physical model, we included various single caves with different scales, velocities, shapes, and fluids, as well as multiple caves in different spatial distributions. SBRs of all caves were extracted and summarized from the migration section

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35

Minniti, Caterina P., Vandana Sachdev, Hannoush Hwaida, et al. "Higher Myocardial and Skeletal Muscle Microvascular Flow in Sickle Cell Disease Patients on Hydroxyurea." Blood 128, no. 22 (2016): 1020. http://dx.doi.org/10.1182/blood.v128.22.1020.1020.

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Abstract Individuals with SCD have recurrent episodes of ischemia-reperfusion in vital organs, and abnormal microcirculation is considered a major determinant of end organ damage. Hydroxyurea (HU) treatment has been shown to produce ATP- and nitric oxide-mediated vasodilation, and to improve red cells deformability Few tools are available to quantitatively measure microvascular blood flow in vivo. The purpose of this study was to assess the ability of a novel ECHO based imaging modality to assess the effect of hydroxyurea on cardiac and skeletal muscle perfusion in patients with sickle cell an

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Martinez-Sanchez, M., B. Jaroux, S. J. Song, and S. Yoo. "Measurement of Turbine Blade-Tip Rotordynamic Excitation Forces." Journal of Turbomachinery 117, no. 3 (1995): 384–92. http://dx.doi.org/10.1115/1.2835673.

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This paper presents results of a program to investigate the magnitude, origin, and parametric variations of destabilizing forces that arise in high power turbines due to blade-tip leakage effects. Five different unshrouded turbine configurations and one configuration shrouded with a labyrinth seal were tested with static offsets of the turbine shaft. The forces along and perpendicular to the offset were measured directly with a dynamometer, and were also inferred from velocity triangles and pressure distributions obtained from detailed flow surveys. These two routes yielded values in fair agre

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NARDI, ANTONIO. "LA QUADRATURA DELLA VELOCITÀ." Nuncius 3, no. 2 (1988): 27–64. http://dx.doi.org/10.1163/182539178x00312.

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Abstract<title> SUMMARY </title>Galileo's theory of falling bodies assumes that the speed increases as the time. The geometrical representation of such a proportional increment is a sequence of similar triangles. The areas of these triangles are connected with the values of distances traversed. Now, Galileo did he seize and accept that an area could ever represent a distance traversed? The author of this paper tries to show why it is reasonable to conclude, that he did, even if with some comprehensible intellectual trouble related to infinitesimal considerations. In this respect it

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Corriveau, D., and S. A. Sjolander. "Influence of Loading Distribution on the Off-Design Performance of High-Pressure Turbine Blades." Journal of Turbomachinery 129, no. 3 (2006): 563–71. http://dx.doi.org/10.1115/1.2464145.

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Linear cascade measurements for the aerodynamic performance of a family of three transonic, high-pressure (HP) turbine blades have been presented previously by the authors. The airfoils were designed for the same inlet and outlet velocity triangles but varied in their loading distributions. The previous papers presented results for the design incidence at various exit Mach numbers, and for off-design incidence at the design exit Mach number of 1.05. Results from the earlier studies indicated that by shifting the loading towards the rear of the airfoil an improvement in the profile loss perform

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Li, Bei, Yang Liu, Mrinal K. Sen, and Zhiming Ren. "Time-space-domain mesh-free finite difference based on least squares for 2D acoustic-wave modeling." GEOPHYSICS 82, no. 4 (2017): T143—T157. http://dx.doi.org/10.1190/geo2016-0464.1.

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Finite-difference (FD) methods approximate derivatives through a weighted summation of function values from neighboring nodes. Traditionally, these neighboring nodes are assumed to be distributed regularly, such as in square or rectangular lattices. To improve geometric flexibility, one option is to develop FD in a mesh-free discretization, in which scattered nodes can be placed suitably with respect to irregular boundaries or arbitrarily shaped anomalies without coordinate transformation or forming any triangles or tetrahedra, etc. These mesh-free FDs have had successful applications, especia

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Бойко, Людмила Георгиевна, Александр Евгеньевич Демин та Наталия Владимировна Пижанкова. "МЕТОД РАСЧЁТА ТЕРМОГАЗОДИНАМИЧЕСКИХ ПАРАМЕТРОВ ТУРБОВАЛЬНОГО ГАЗОТУРБИННОГО ДВИГАТЕЛЯ НА ОСНОВЕ ПОВЕНЦОВОГО ОПИСАНИЯ ЛОПАТОЧНЫХ МАШИН. ЧАСТЬ II. ОПРЕДЕЛЕНИЕ ПАРАМЕТРОВ СТУПЕНЕЙ И МНОГОСТУПЕНЧАТЫХ КОМПРЕССОРОВ". Aerospace technic and technology, № 1 (7 березня 2019): 18–28. http://dx.doi.org/10.32620/aktt.2019.1.02.

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Gas Turbine Engine (GTE) operating characteristics such as thrust (or power), specific fuel consumption and other cycle parameters on different regimes, can be determined by engine modeling and applying correspondent calculation method. Its accuracy is the function of the engine’s element maps definition precision. So these maps representations influence for engines investigation results significantly. Main points and equation system for engine performances calculation method were represented in Part I of this article. The method gives an opportunity for the flow path thermodynamical parameter

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Bartenev, Ivan, and Aleksandr Petkov. "ANALYSIS OF STRUCTURES AND WORK PROCESSES OF TECHNICAL FACILITIES FOR PREVENTION AND SUPPRESSION OF FOREST FIRES BY SOIL." Actual directions of scientific researches of the XXI century: theory and practice 8, no. 2 (2020): 5–11. http://dx.doi.org/10.34220/2308-8877-2020-8-2-5-11.

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The analysis of designs of domestic and foreign ground-throwing machines and conducted research on extinguishing a forest grass-roots fire by throwing soil. It is established that for carrying out high-quality preventive and forest fire works, it is advisable to use technical means that combine active and passive working bodies in their design. This will allow combining the process of pre-treatment of soil and further release of loosened soil in a given direction, as well as significantly increase the efficiency of the technological process of creating mineralized strips. Based on the mathemat

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Bin Ramli, Mohd Syaifullah, Abdul Basit, Ku Zilati Ku Shaari, and Lau Kok Keong. "Study of the Effect of Surface Roughness on Droplet Spreading Behavior Using CFD Modeling." Applied Mechanics and Materials 625 (September 2014): 378–81. http://dx.doi.org/10.4028/www.scientific.net/amm.625.378.

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Water droplet spreading has been simulated at impact velocity of 3.0 m/s, 1.5 m/s and 0.5 m/s on surfaces with texture of ‘triangle’, ‘square’, ‘curve’ as well as smooth surface of aluminum. Higher impact velocity induced the droplet to spread faster and has a bigger diameter. At high impact velocity, spreading factor cannot be determined due to splashing and droplet break ups. In addition, at 1.5 m/s the phenomenon of splashing was found to be almost absent except on the surface with ‘square’ texture. ‘Square’ surface tends to splash earlier compared to other surfaces and is followed by ‘tria

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Pan, Minqiang, Yong Tang, Hao Yu, and Hongqing Chen. "Modeling of velocity distribution among microchannels with triangle manifolds." AIChE Journal 55, no. 8 (2009): 1969–82. http://dx.doi.org/10.1002/aic.11817.

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Iwahashi, Yohei, Masaki Miyazato, Masaaki Miyajima, et al. "Extension of Stacking Faults in 4H-SiC pn Diodes under a High Current Pulse Stress." Materials Science Forum 897 (May 2017): 218–21. http://dx.doi.org/10.4028/www.scientific.net/msf.897.218.

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We investigated the expansion of stacking faults (SFs) under a high current pulse stress in detail. In situ observations showed bar-shaped SFs and two types of triangle SFs with different nucleation sites. The calculated partial dislocation velocity of the bar-shaped SFs was four times faster than that of the triangle SFs. The temperature dependence of the partial dislocation velocity was used to estimate activation energies of 0.23±0.02 eV for bar-shaped SFs and 0.27±0.05 eV for triangle SFs. We also compared the electrical characteristics before and after the stress. The forward voltage drop

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Beiner, L. "Kinematics of a n–bay triangle–triangle variable geometry truss manipulator." Robotica 10, no. 3 (1992): 263–67. http://dx.doi.org/10.1017/s0263574700007992.

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SUMMARYVariable geometry truss manipulators (VGTM) are static trusses where the lengths of some members can be varied, allowing one to control the position of the free end relative to the fixed one. This paper deals with a planar VGTM consisting of a n–bay triangle-triangle truss with one variable length link (i.e. one DOF) per bay. Closed-form solutions to the forward, inverse, and velocity kinematics of a 3-DOF version of this VGTM are presented, while the forward and inverse kinematics of an n–DOF (redundant) one are solved by a recursive and an iterative method, respectively. A numerical e

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Zhu, Jianjun, Haiwen Zhu, Guangqiang Cao, et al. "A New Mechanistic Model To Predict Boosting Pressure of Electrical Submersible Pumps Under High-Viscosity Fluid Flow with Validations by Experimental Data." SPE Journal 25, no. 02 (2019): 744–58. http://dx.doi.org/10.2118/194384-pa.

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Summary As the second most widely used artificial-lift method in petroleum production (and first in accumulative production), electrical submersible pumps (ESPs) increase flow rates by converting kinetic energy to hydraulic pressure. ESPs are routinely characterized with water flow, and water performance curves are provided by the manufacturers (catalog curves) for designing ESP-based artificial-lift systems. However, the properties of hydrocarbon fluids are very different from those of water, especially the dynamic viscosities, which can significantly alter the ESP performance. Most of the ex

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Li, Guan Nan, Hui Ying Dong, and Hong Li Xu. "Triangle Formation Control of Multi-AUVs with Communication Constraints." Applied Mechanics and Materials 596 (July 2014): 631–35. http://dx.doi.org/10.4028/www.scientific.net/amm.596.631.

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Aimed at solving the problem of multi-AUVs formation control, an analysis has been made on a triangle formation based on leader-follower construction, with a multi-AUVs formation controller designed with communication constraints taken into account. The desired velocity of the follower is the resultant velocity of three component velocities, each of which has different function. The convergence of the proposed controller is proved by establishing an objective function that can represents the status of the formation. Simulation experiments are carried out to demonstrate the proposed controller

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Zhang, Yu Shu. "Analysis and Calculation of Transmission Ratio of Simpson Planetary Gear Mechanism Based on Velocity Graphic Method." Advanced Materials Research 889-890 (February 2014): 532–36. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.532.

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The paper summarizes the principle of applying velocity graphic method to analyze Simpson planetary gear mechanism, which provides guidance for analysis procedure. The movement of each element in the mechanism can be intuitively understood through drawing the linear velocity vectors of three constant velocity points. The similar triangle principle is used to calculated transmission ratio of each transmission scheme in the linear velocity vector diagram, and the correctness of the analysis method and process is verified by the transmission ratio calculated by velocity graphic method and analyti

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Monteagudo, Jorge E. P., and Abbas Firoozabadi. "Control-Volume Model for Simulation of Water Injection in Fractured Media: Incorporating Matrix Heterogeneity and Reservoir Wettability Effects." SPE Journal 12, no. 03 (2007): 355–66. http://dx.doi.org/10.2118/98108-pa.

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Summary The control-volume discrete-fracture (CVDF) model is extended to incorporate heterogeneity in rock and in rock-fluid properties. A novel algorithm is proposed to model strong water-wetting with zero capillary pressure in the fractures. The extended method is used to simulate:oil production in a layered faulted reservoir,laboratory displacement tests in a stack of matrix blocks with a large contrast in fracture and matrix capillary pressure functions, andwater injection in 2D and 3D fractured media with mixed-wettability state. Our results show that the algorithm is suitable for the sim

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Su, Mingxiao, Xiyun Jiao, Jiang Li, Shuyu Wu, and Tianao Wu. "Accuracy and Reliability Analysis of Pipe Irrigation Metering Device for Sandy Water Source." Water 13, no. 7 (2021): 947. http://dx.doi.org/10.3390/w13070947.

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Sandy water sources are widely distributed and are important for agricultural development. However, no explicit result has been achieved in the research of the accuracy and reliability of pipeline metering devices as well as flow rate measurement objects (water or water–sand) of different metering devices in the process of pipelines conveying muddy water. In this study, seven kinds of sediment concentration gradients, C0–C6 (0.2–7.19%), and three different flow velocities (1.0 m/s, 1.25 m/s, 1.5 m/s) were set up, and a comparison measuring method was used to compare the flow values of three ki

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