scholarly journals Discrimination of Surface Topographies Created by Two-Stage Process by Means of Multiscale Analysis

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7044
Author(s):  
Tomasz Bartkowiak ◽  
Karol Grochalski ◽  
Bartosz Gapiński ◽  
Michał Wieczorowski
Keyword(s):  
Curvature Tensor ◽  
Relative Length ◽  
Sampling Interval ◽  
Multiscale Methods ◽  
Surface Metrology ◽  
Technological Parameters ◽  
Central Wavelength ◽  
Characterization Methods ◽  
Geometrical Properties ◽  
Length And Area

The fundamental issue in surface metrology is to provide methods that can allow the establishment of correlations between measured topographies and performance or processes, or that can discriminate confidently topographies that are processed or performed differently. This article presents a set of topographies from two-staged processed steel rings, measured with a 3D contact profilometer. Data were captured individually from four different regions, namely the top, bottom, inner, and outer surfaces. The rings were manufactured by drop forging and hot rolling. Final surface texture was achieved by mass finishing with spherical ceramic media or cut wire. In this study, we compared four different multiscale methods: sliding bandpass filtering, three geometric length- and area-scale analyses, and the multiscale curvature tensor approach. In the first method, ISO standard parameters were evaluated as a function of the central wavelength and bandwidth for measured textures. In the second and third method, complexity and relative length and area were utilized. In the last, multiscale curvature tensor statistics were calculated for a range of scales from the original sampling interval to its forty-five times multiplication. These characterization parameters were then utilized to determine how confident we can discriminate (through F-test) topographies between regions of the same specimen and between topographies resulting from processing with various technological parameters. Characterization methods that focus on the geometrical properties of topographic features allowed for discrimination at the finest scales only. Bandpass filtration and basic height parameters Sa and Sq proved to confidently discriminate against all factors at all three considered bandwidths.

Polynomial Model Set and its Interacting Multiple Model Algorithms

2012 ◽  
Vol 562-564 ◽  
pp. 2038-2044
Author(s):  
Jin Xiao Zhao ◽  
Jian Qiu Zhang ◽  
Dong Ming Zhou
Keyword(s):  
Sampling Interval ◽  
Polynomial Model ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Geometrical Properties ◽  
Filter Performance ◽  
Maneuvering Target ◽  
Polynomial Curve ◽  
Motion Modes ◽  
Model Set

From the maneuvering target orbit on the geometrical properties, according to different motion modes track corresponding to different order number polynomial curve, using the least squares fitting structure, this paper gives out a group of various motion modes matching the mathematical model—polynomial model set (PMS), and gives distinct mathematical process. PMS covers all the motion modes theoretically, easy to choose according to the practical situation and expand, especially suitable for single model can not accurately describe the complex sports scene. The model need not consider sampling interval, without lowering the filter performance at the same time, reduced prior knowledge dependence. Finally, simulation results indicate that the correctness and validity and practicality.

Characterization of 3D Surface Texture Directionality Using Multi-Scale Curvature Tensor Analysis

2017 ◽  
Author(s):  
Tomasz Bartkowiak
Keyword(s):  
Curvature Tensor ◽  
Surface Texture ◽  
Sampling Interval ◽  
Tensor Analysis ◽  
Principal Curvatures ◽  
Multi Scale ◽  
Principal Directions ◽  
2D And 3D ◽  
3D Surface Texture

Anisotropy of surface texture can in many practical cases significantly affect the interaction between the surface and phenomena that influence or are influenced by the topography. Tribological contacts in sheet forming, wetting behavior or dental wear are good examples. This article introduces and exemplifies a method for quantification and visualization of anisotropy using the newly developed 3D multi-scale curvature tensor analysis. Examples of a milled steel surface, which exhibited an evident anisotropy, and a ruby contact probe surface, which was the example of isotropic surface, were measured by the confocal microscope. They were presented in the paper to support the proposed approach. In the method, the curvature tensor T is calculated using three proximate unit vectors normal to the surface. The multi-scale effect is achieved by changing the size of the sampling interval for the estimation of the normals. Normals are estimated from regular meshes by applying a covariance matrix method. Estimation of curvature tensor allows determination of two directions around which surface bends the most and the least (principal directions) and the bending radii (principal curvatures). The direction of the normal plane, where the curvature took its maximum, could be plotted for each analyzed region and scale. In addition, 2D and 3D distribution graphs could be provided to visualize anisotropic or isotropic characteristics. This helps to determine the dominant texture direction or directions for each scale. In contrast to commonly used surface isotropy/anisotropy determination techniques such as Fourier transform or autocorrelation, the presented method provides the analysis in 3D and for every region at each scale. Thus, different aspects of the studied surfaces could clearly be seen at different scales.

Measurements of the Statistical Microgeometry of Engineering Surfaces

1979 ◽  
Vol 101 (4) ◽  
pp. 409-417 ◽  
Author(s):  
R. S. Sayles ◽  
T. R. Thomas
Keyword(s):  
Nearest Neighbor ◽  
Sampling Interval ◽  
Random Surface ◽  
Geometrical Properties ◽  
Grid Sampling ◽  
Anisotropic Structures ◽  
Basic Relationship ◽  
Moment Approach ◽  
Non Gaussian ◽  
Good Agreement

Surface and profile measurements and their resulting statistics, based on samples of up to half a million heights, are compared and their interrelationship examined for several common engineering surfaces. The measurements are employed to check the applicability of the spectral moment approach to random surface specification. This technique relates many important geometrical properties of a surface to those of its constituent profiles. A relationship is found to exist between the sampling interval and the spatial size of features accommodated by this form of approach. This explains, for example, why 4 and 8 nearest neighbor summit-density analyses based on the same square grid sampling interval reveal very different results. Having established this basic relationship, good agreement is found between theory and measurement over a large range of sampling intervals. In particular, summit densities and distributions are shown to agree well with theory even for non-Gaussian height distributions. It is shown how the isotropic analysis can be extended to cover directionally anisotropic structures such as ground surfaces by defining equivalent movements based on two profiles at right angles. Here again measurements are in good agreement with theory.

Differential taxonomy of Haemogamasus nidi Michael, 1892 and H. nidiformis Bregetova, 1955 (Acari, Mesostigmata: Laelapidae)

1979 ◽  
Vol 10 (1) ◽  
pp. 73-78
Author(s):  
Lars Lundqvist ◽  
Anders Edler
Keyword(s):  
Relative Length ◽  
Type Material ◽  
Length And Area

AbstractA collection of Haemogamasus nidi Michael, 1892 and H. nidiformis Bregetova, 1955 from Scandinavia and NE USSR was compared with type material. Differences in the number of setae and the relative length and area of the genito-ventral shield can be used to seperate females of the two species.

scholarly journals Glacier change of the Columbia Icefield, Canadian Rocky Mountains, 1919–2009

2013 ◽  
Vol 59 (216) ◽  
pp. 671-686 ◽  
Author(s):  
Christina Tennant ◽  
Brian Menounos
Keyword(s):  
Volume Change ◽  
Rocky Mountains ◽  
Relative Length ◽  
Aerial Photographs ◽  
Glacier Change ◽  
Volume Loss ◽  
Canadian Rocky Mountains ◽  
Elevation Change ◽  
Glacier Changes ◽  
Length And Area

AbstractWe determined length, area, elevation and volume change of the Columbia Icefield using Interprovincial Boundary Commission Survey maps from 1919, eight sets of aerial photographs from 1948 to 1993, and satellite data from 1999 to 2009. Over the period 1919–2009, glaciers on average retreated 1150 ± 34 m and shrank by 2.4 ± 0.2 km2. Total area loss was 59.6 ± 1.2 km2 (23 ± 5%), and mean elevation change was −49 ± 25 m w.e., resulting in a total volume loss of 14.3 ± 2.0 km3 w.e. Large outlet glaciers experienced the greatest absolute ice loss, while small, detached glaciers lost the most relative length and area. Thinning rates of debris-covered ice were 30–60% lower than those for clean ice. All glacier changes were significantly correlated with each other (p < 0.01), with r values ranging from 0.54 to 0.82. Temperature is correlated with length and area change over periods lagged 1–5 years (p < 0.05), and with elevation and volume change over periods lagged 9–18 years (p < 0.05). Precipitation is correlated with glacier change over periods lagged 1–10 years (p < 0.05).

A Characterization of Process–Surface Texture Interactions in Micro-Electrical Discharge Machining Using Multiscale Curvature Tensor Analysis

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Tomasz Bartkowiak ◽  
Christopher A. Brown
Keyword(s):  
Curvature Tensor ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Sampling Interval ◽  
Tensor Analysis ◽  
Strong Correlations ◽  
Micro Electrical Discharge Machining ◽  
Surface Topographies ◽  
Unit Vectors

The objectives of this work are to demonstrate the use of multiscale curvature tensor analysis for characterizing surfaces of stainless steel created by micro-electrical discharge machining (μEDM), and to study the strengths of the correlations between discharge energies and resulting surface curvatures (i.e., principal, Gaussian, or mean curvatures) and how they change with scale. Surfaces were created by μEDM techniques using energies from 18 nJ to 16,500 nJ and measured by confocal microscope. The curvature tensor T is calculated using three proximate unit vectors normal to the surface. The multiscale effect is achieved by changing the size of the sampling interval for the estimation of the normals. Normals are estimated from regular meshes by applying a covariance matrix method. Strong correlations (R2 > 0.9) are observed between calculated principal maximal and minimal as well as mean and Gaussian curvatures and discharge energies. This method allows detailed analysis of the nature of surface topographies and suggests that different formation processes governed the creation of surfaces created by higher energies.

scholarly journals A new curvaturelike tensor field in an almost contact Riemannian manifold II

2018 ◽  
Vol 103 (117) ◽  
pp. 113-128 ◽  
Author(s):  
Koji Matsumoto
Keyword(s):  
Riemannian Manifold ◽  
Curvature Tensor ◽  
Tensor Field ◽  
Sasakian Manifold ◽  
Tensor Fields ◽  
Geometrical Properties ◽  
Conformal Curvature ◽  
Conformal Curvature Tensor ◽  
Riemannian Curvature Tensor ◽  
Contact Riemannian Manifold

In the last paper, we introduced a new curvaturlike tensor field in an almost contact Riemannian manifold and we showed some geometrical properties of this tensor field in a Kenmotsu and a Sasakian manifold. In this paper, we define another new curvaturelike tensor field, named (CHR)3-curvature tensor in an almost contact Riemannian manifold which is called a contact holomorphic Riemannian curvature tensor of the second type. Then, using this tensor, we mainly research (CHR)3-curvature tensor in a Sasakian manifold. Then we define the notion of the flatness of a (CHR)3-curvature tensor and we show that a Sasakian manifold with a flat (CHR)3-curvature tensor is flat. Next, we introduce the notion of (CHR)3-?-Einstein in an almost contact Riemannian manifold. In particular, we show that Sasakian (CHR)3- ?-Einstein manifold is ?-Einstain. Moreover, we define the notion of (CHR)3- space form and consider this in a Sasakian manifold. Finally, we consider a conformal transformation of an almost contact Riemannian manifold and we get new invariant tensor fields (not the conformal curvature tensor) under this transformation. Finally, we prove that a conformally (CHR)3-flat Sasakian manifold does not exist.

scholarly journals Multiscale Characterizations of Surface Anisotropies

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3028 ◽  
Author(s):  
Tomasz Bartkowiak ◽  
Johan Berglund ◽  
Christopher A. Brown
Keyword(s):  
Large Scale ◽  
Bandpass Filters ◽  
Multiscale Methods ◽  
The Other ◽  
Principal Curvatures ◽  
Characterization Methods ◽  
Actual Surface ◽  
Aspect Ratios ◽  
Surface Measurements ◽  
Curvature Tensors

Anisotropy can influence surface function and can be an indication of processing. These influences and indications include friction, wetting, and microwear. This article studies two methods for multiscale quantification and visualization of anisotropy. One uses multiscale curvature tensor analysis and shows anisotropy in horizontal coordinates i.e., topocentric. The other uses multiple bandpass filters (also known as sliding bandpass filters) applied prior to calculating anisotropy parameters, texture aspect ratios (Str) and texture directions (Std), showing anisotropy in horizontal directions only. Topographies were studied on two milled steel surfaces, one convex with an evident large scale, cylindrical form anisotropy, the other nominally flat with smaller scale anisotropies; a µEDMed surface, an example of an isotropic surface; and an additively manufactured surface with pillar-like features. Curvature tensors contain the two principal curvatures, i.e., maximum and minimum curvatures, which are orthogonal, and their directions, at each location. Principal directions are plotted for each calculated location on each surface, at each scale considered. Histograms in horizontal coordinates show altitude and azimuth angles of principal curvatures, elucidating dominant texture directions at each scale. Str and Std do not show vertical components, i.e., altitudes, of anisotropy. Changes of anisotropy with scale categorically failed to be detected by traditional characterization methods used conventionally. These multiscale methods show clearly in several representations that anisotropy changes with scale on actual surface measurements with markedly different anisotropies.

scholarly journals Hot-probe method for evaluation of majority charged carriers concentration in semiconductor thin films

2013 ◽  
Vol 26 (3) ◽  
pp. 187-195 ◽  
Author(s):  
Alexander Axelevitch ◽  
Gady Golan
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Probe Method ◽  
Technological Parameters ◽  
Film Properties ◽  
Characterization Methods ◽  
Novel Approach ◽  
Semiconductor Thin Films ◽  
Hot Probe ◽  
Definition Of

Physical properties of thin films significantly differ from those of bulk materials. Also, these properties are influenced from the technological parameters of the films deposition technique. Therefore, characterization methods for evaluation of thin film properties become of high importance. A novel approach to the well-known "Hot-Probe" method is proposed and applied in our work. The conventional Hot Probe characterization method enables only the definition of a semiconductor type, P or N, by identifying the majority of the charged carriers. According to the new Hot Probe technique, one can measure and calculate the impurities concentration and charged carriers dynamic parameters. Feasibility proof of the upgraded Hot Probe method was done in Si and Ge bulk, and in thin film semiconductor samples of In2O3 and VO2.

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