scholarly journals Effect of location and feature cues on the masking function for location

2010 ◽  
Vol 3 (9) ◽  
pp. 733-733
Author(s):  
S. Baldassi ◽  
P. Verghese
Keyword(s):  
Masking Function

Low-dimensional dynamics of a turbulent wall flow

2001 ◽  
Vol 435 ◽  
pp. 81-91 ◽  
Author(s):  
JAVIER JIMÉNEZ ◽  
MARK P. SIMENS
Keyword(s):  
Numerical Simulations ◽  
Single Copy ◽  
Streamwise Vortices ◽  
Low Velocity ◽  
Wall Distance ◽  
Wall Flow ◽  
Low Dimensional ◽  
Turbulent Wall ◽  
Low Dimensional Dynamics ◽  
Masking Function

The low-dimensional dynamics of the structures in a turbulent wall flow are studied by means of numerical simulations. These are made both ‘minimal’, in the sense that they contain a single copy of each relevant structure, and ‘autonomous’ in the sense that there is no outer turbulent flow with which they can interact. The interaction is prevented by a numerical mask that damps the flow above a given wall distance, and the flow behaviour is studied as a function of the mask height. The simplest case found is a streamwise wave that propagates without change. It takes the form of a single wavy low-velocity streak flanked by two counter-rotating staggered quasi-streamwise vortices, and is found when the height of the numerical masking function is less than δ+1 ≈ 50. As the mask height is increased, this solution bifurcates into an almost-perfect limit cycle, a two-frequency torus, weak chaos, and full-edged bursting turbulence. The transition is essentially complete when δ+1 ≈ 70, even if the wall-parallel dimensions of the computational box are small enough for bursting turbulence to be metastable, lasting only for a few bursting cycles. Similar low-dimensional dynamics are found in somewhat larger boxes, containing two copies of the basic structures, in which the bursting turbulence is self-sustaining.

scholarly journals A u-shaped backward masking function in vision

1965 ◽  
Vol 2 (1-12) ◽  
pp. 75-76 ◽  
Author(s):  
Naomi Weisstein ◽  
Ralph Norman Haber
Keyword(s):  
Backward Masking ◽  
Masking Function

Experimental Study on Corrosion Prevention of a Multilayer Coating System

2014 ◽  
Vol 881-883 ◽  
pp. 1307-1311
Author(s):  
Huan Yang ◽  
Shi Qiu ◽  
Yu Feng Lu ◽  
Zhen Xing Liu ◽  
Fei Lu
Keyword(s):  
Corrosion Protection ◽  
Multilayer Coating ◽  
Metallic Matrix ◽  
Coating System ◽  
Corrosion Prevention ◽  
Aggregate Concrete ◽  
Layered Coating ◽  
Prevention System ◽  
Masking Function ◽  
Energy Disperse Spectroscopy

Aiming to the corrosion prevention of 16MnR steel surface in the light aggregate concrete, the paper applies a kind of corrosion prevention system composed of layered coating. It utilizes measurement methods such as field emission scanning electron microscopy and energy disperse spectroscopy to study the corrosion and change process of this kind of coating system in the surface of 16MnR steel in the environment of light aggregate concrete and make the evaluation on its effect of corrosion protection. The experiment result indicates that due to its mechanical masking function, the layered coating system can effectively restrain immersion of the corrosive medium in early corrosion period so as to protect the metallic matrix. With the deepening of the corrosion, the nanometer Zn particle has the function of cathodic protection on the metallic matrix, effectively enhancing the comprehensive corrosion protection ability of the coating system.

Application of an Immersed Boundary Method to Flow in Cerebral Aneurysms and Porous Media

2010 ◽  
Author(s):  
Julia Mikhal ◽  
David J. Lopez Penha ◽  
Steffen Stolz ◽  
Bernard J. Geurts
Keyword(s):  
Poiseuille Flow ◽  
Stokes Equations ◽  
Spatial Arrangement ◽  
Computational Method ◽  
Implicit Time ◽  
Immersed Boundary ◽  
Time Stepping ◽  
Flow Through ◽  
Masking Function ◽  
Ib Method

We present the development and application of an immersed boundary (IB) method for the simulation of incompressible flow inside and around complex geometrical shapes and cavities. The IB method is based on a volume-penalization method that is applied throughout the domain, rendering the velocity in stationary solid parts negligibly small, while the flow in the open parts of the domain is governed by the Navier-Stokes equations. The flow solver is based on a skew-symmetric finite-volume discretization in combination with explicit time-stepping for the convective and viscous fluxes, and implicit time-stepping for the IB forcing term. The complex domain is characterized in terms of a so-called ‘masking function’ which equals unity in the solid parts and zero in the open parts of the domain. The focus is on the accuracy with which gradients of the solution close to solid walls can be approximated using the IB methodology. We investigate this for flow through a model of an aneurysm as may develop in the circle of Willis in a human brain, and to flow in a structured porous medium composed of a regular spatial arrangement of square rods. The shear stress acting on the vessel walls in case of flow through an aneurysm, and the permeability of the porous material, are analyzed. The computational method converges as a first order method for Poiseuille flow, with a considerable influence derived from the precise definition of the masking function near solid-fluid interfaces. We identify the best masking function strategy and show that for plane Poiseuille flow even second order convergence may be obtained. Qualitatively reliable results are obtained already at modest resolutions of 8–16 grid cells across a characteristic opening in the flow domain, e.g., the vessel diameter or the size of the gap between individual square rods.

scholarly journals A u-shaped backward masking function in vision: A partial replication of the Weisstein and Haber study with two ring sizes

1965 ◽  
Vol 3 (1-12) ◽  
pp. 79-80 ◽  
Author(s):  
M. S. Mayzner ◽  
M. H. Blatt ◽  
W. H. Buchsbaum ◽  
R. T. Friedel ◽  
P. E. Goodwin ◽  
...  
Keyword(s):  
Partial Replication ◽  
Backward Masking ◽  
Masking Function

scholarly journals Failure to replicate a reported U-shaped visual masking function

1969 ◽  
Vol 15 (4) ◽  
pp. 195-196 ◽  
Author(s):  
Charles W. Eriksen ◽  
Philip H. Marshall
Keyword(s):  
Visual Masking ◽  
Masking Function
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