DEMONSTRATION OF WATERSHED SEGMENTATION ON SIMULATED SURFACE TOPOGRAPHY DATA

2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Mohd Fauzi Ismail ◽  
Nor Hidayawati Mohd Zaini ◽  
Talib Ria Jaafar ◽  
Nuraini Che Pin
Keyword(s):  
Surface Topography ◽  
Surface Texture ◽  
Simulated Data ◽  
Functional Requirements ◽  
Watershed Segmentation ◽  
Simulated Surface ◽  
The Hill ◽  
The Relationship ◽  
Topography Data ◽  
Areal Surface

Surface texture comprises of many features of interest, which may or may not be essential for surface functional requirements. Features on the surface topography data refers to the peak, pit and the relationship between them; instead of the point on the valleys only. Hence, the objective of this paper is to demonstrate the watershed segmentation on the simulated surface topography data. Watershed segmentation is applied on the selected areal surface texture to determine the regions of the features of the hill and dales. The segmentation of the features is developed by using MATLAB. The developed application is then validated with the simulated topography data. The application’s result on the simulated data shows that, the watershed segmentation method works as intended.  

scholarly journals Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1790
Author(s):  
Wojciech Macek
Keyword(s):  
Fractal Dimension ◽  
Fracture Surface ◽  
Surface Topography ◽  
Fatigue Loading ◽  
Loading Conditions ◽  
Surface Method ◽  
Loading Ratio ◽  
Topography Data ◽  
Areal Surface ◽  
Total Fracture

This paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and fatigue loading conditions was found. Distinctions in particular regions of cracks were also recognized through proving the correctness and universality of the total fracture surface method. The influence of fatigue loading parameters on the surface topography of fatigue fractures was demonstrated. For the analyzed cases, results show that the fractal dimension and standard surface topography parameters represent a correlation between them and loading conditions. As a single parameter, the appropriate loading ratio cannot be outright calculated with fractal dimension, but can be estimated with some approximation, taking into account additional assumptions.

Effect of osmotic swelling and shrinkage on Na(+)-K+ pump activity in mammalian cardiac myocytes

1993 ◽  
Vol 265 (5) ◽  
pp. C1201-C1210 ◽  
Author(s):  
D. W. Whalley ◽  
L. C. Hool ◽  
R. E. Ten Eick ◽  
H. H. Rasmussen
Keyword(s):  
Ventricular Myocytes ◽  
Pump Current ◽  
Hill Equation ◽  
Cell Swelling ◽  
Intracellular Na Activity ◽  
Single Ventricular Myocytes ◽  
Hyperosmolar Solutions ◽  
Hill Coefficients ◽  
The Hill ◽  
The Relationship

The effect on the sarcolemmal Na(+)-K+ pump of exposure to anisosmolar solutions was examined using whole cell patch clamping and ion-selective microelectrodes. Na(+)-K+ pump currents were measured in single ventricular myocytes by using pipette Na+ concentrations ([Na]pip) of 0-70 mM. The relationship between [Na]pip and pump current was well described by the Hill equation. The [Na]pip for half-maximal pump current (K0.5) was 21.4 mM in isosmolar (310 mosM) solution. K0.5 was 12.8 mM during cell swelling in hyposmolar solution (240 mosM) and 39.0 mM during cell shrinkage in hyperosmolar solution (464 mosM). The maximal pump currents, derived from the best fit of the Hill equation, and the Hill coefficients were similar in isosmolar, hyposmolar, and hyperosmolar solutions. A sustained (> 20 min) decrease in the intracellular Na+ activity developed during exposure of intact papillary muscles to hyposmolar solutions, and a sustained increase developed during exposure to hyperosmolar solutions. We conclude that osmotic myocyte swelling stimulates the sarcolemmal Na(+)-K+ pump at near-physiological levels of intracellular Na+, whereas shrinkage inhibits the pump. These changes are due to increases and decreases, respectively, in the apparent affinity of the pump for Na+.

Perspective on the relationship between GABAA receptor activity and the apparent potency of an inhibitor

2021 ◽  
Vol 19 ◽  
Author(s):  
Allison L. Germann ◽  
Spencer R. Pierce ◽  
Alex S. Evers ◽  
Joe Henry Steinbach ◽  
Gustav Akk
Keyword(s):  
Gabaa Receptor ◽  
Hill Equation ◽  
Response Relationship ◽  
Inhibition Concentration ◽  
Level Of Activity ◽  
Control Response ◽  
The Hill ◽  
The Relationship ◽  
Inhibition Curve ◽  
Receptor Channel

Background : In electrophysiological experiments inhibition of a receptor-channel, such as the GABAA receptor, is measured by co-applying an agonist producing a predefined control response with an inhibitor to calculate the fraction of the control response remaining in the presence of the inhibitor. The properties of the inhibitor are determined by fitting the inhibition concentration-response relationship to the Hill equation to estimate the midpoint (IC50) of the inhibition curve. Objective: We sought to estimate here the sensitivity of the fitted IC50 to the level of activity of the control response. Methods: The inhibition concentration-response relationships were calculated for models with distinct mechanisms of inhibition. In Model I, the inhibitor acts allosterically to stabilize the resting state of the receptor. In Model II, the inhibitor competes with the agonist for a shared binding site. In Model III, the inhibitor stabilizes the desensitized state. Results: The simulations indicate that the fitted IC50 of the inhibition curve is sensitive to the degree of activity of the control response. In Models I and II, the IC50 of inhibition was increased as the probability of being in the active state (PA) of the control response increased. In Model III, the IC50 of inhibition was reduced at higher PA. Conclusions: We infer that the apparent potency of an inhibitor depends on the PA of the control response. While the calculations were carried out using the activation and inhibition properties that are representative of the GABAA receptor, the principles and conclusions apply to a wide variety of receptor-channels.

scholarly journals Wicksell's Problem in Local Stereology

2013 ◽  
Vol 45 (4) ◽  
pp. 925-944
Author(s):  
Ó. Thórisdóttir ◽  
M. Kiderlen
Keyword(s):  
Reference Point ◽  
Simulated Data ◽  
Domain Of Attraction ◽  
Spherical Particles ◽  
Section Profile ◽  
Particle Parameters ◽  
The Individual ◽  
The Relationship ◽  
Theoretical Results ◽  
Isotropic Random

Wicksell's classical corpuscle problem deals with the retrieval of the size distribution of spherical particles from planar sections. We discuss the problem in a local stereology framework. Each particle is assumed to contain a reference point and the individual particle is sampled with an isotropic random plane through this reference point. Both the size of the section profile and the position of the reference point inside the profile are recorded and used to recover the distribution of the corresponding particle parameters. Theoretical results concerning the relationship between the profile and particle parameters are discussed. We also discuss the unfolding of the arising integral equations, uniqueness issues, and the domain of attraction relations. We illustrate the approach by providing reconstructions from simulated data using numerical unfolding algorithms.

The Influence of Surface Texture on Abrasive Wear

2019 ◽  
Vol 823 ◽  
pp. 33-40 ◽  
Author(s):  
Yu Tong Hu ◽  
Yong Yong He ◽  
Wei Wang
Keyword(s):  
Friction Coefficient ◽  
Femtosecond Laser ◽  
Abrasive Wear ◽  
White Light ◽  
Surface Texture ◽  
Friction Surface ◽  
Surface Texturing ◽  
Experimental Results ◽  
The Relationship ◽  
Main Factor

Friction happens everywhere. Abrasives generated in tribological process will result in secondary wear. Abrasive wear is a kind of rather common but harmful wear, which is the main reason for the damage of fifty-percent mechanical components by friction. Surface texturing is an effective method to improve the tribological and lubricating performance of tribo-pairs. In this paper, with different-size diamond particles added into the lubricant and a surface of the tribo-pairs textured by different parameters (diameter and depth) with femtosecond laser, the relationship between the surface texture and the abrasive wear was researched, and the influence of the texture on the abrasive wear was analyzed. The friction experiments were carried out on UMT3. The microstructures were tested and analyzed by SEM, microscope and White Light Interferometer respectively. The experimental results showed that the size of the surface texture, compared with that of abrasives, is the main factor which determines the friction coefficient. As the size of the surface texture is much bigger than that of the abrasives, the texture can accommodate the abrasives efficiently, and thus the friction coefficient is reduced efficiently.

scholarly journals Functional Importance of Surface Texture Parameters

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5326
Author(s):  
Pawel Pawlus ◽  
Rafal Reizer ◽  
Michal Wieczorowski
Keyword(s):  
Literature Review ◽  
Surface Topography ◽  
Surface Texture ◽  
3D Analysis ◽  
Functional Importance ◽  
Hybrid Functional ◽  
Functional Feature ◽  
Texture Parameters ◽  
Future Challenges ◽  
Selection Of

Areal 3D analysis of surface texture gives more opportunities than a study of 2D profiles. Surface topography evaluation, considered as 3D dimensional analysis in micro or nanoscales, plays an important role in many fields of science and life. Among many texture parameters, those connected with height are the most often used. However, there are many other parameters and functions that can provide additional important information regarding functional behaviour of surfaces in different applications. The knowledge about the functional importance of various surface properties is low. This review tries to fill this gap. Surface texture parameters are presented in various groups: height, spatial, hybrid, functional, feature, and others. Based on experiences of the present authors and literature review, the relationships among various surface parameters and functional properties are described. A proposal of a selection of parameters on the basis of their functional significations is provided. Considerations for future challenges are addressed.

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