Two 3D Fractal-Based Approaches for Topographical Characterization: Richardson Patchwork versus Sdr.

Various methods exist for multiscale characterization of surface topographies, each offering unique insights and applications. The study focuses on fractal-based approaches, distinguishing themselves by leveraging fractals to analyze surface complexity. Specifically, the Richardson Patchwork method, used in the ASME B46.

Height Fluctuations and Surface Gradients in Topographic Measurements.

Topographic maps are composed of pixels associated with coordinates (, , ) on a surface. Each pixel location (, ) is linked with fluctuations in a measured height sample (). Fluctuations here are uncertainties in heights estimated from multiple topographic measurements at the same position.

A Multiscale Topographical Surface Analysis of High Entropy Alloys Coatings by Laser Melting.

High Entropy Alloys (HEAs) coatings obtained by laser melting (LM) technique were studied through a multiscale topographical surface analysis using a focus variation microscope. The laser melting creates a multiscale topography from under-powder size (incomplete or complete powder melting) to upper-powder size (process conditions). The surface topography must be optimized because of the significant influence on friction and material transfer during sliding wear.

Top-down Determination of Fluctuations in Topographic Measurements.

A top-down method is presented and studied for quantifying topographic map height () fluctuations directly from measurements on surfaces of interest. Contrary to bottom-up methods used in dimensional metrology, this method does not require knowledge of transfer functions and fluctuations of an instrument. Fluctuations are considered here to be indicative of some kinds of uncertainties.

Surface Inspection and Description in Metrology and Tribology-Vol.1.

The primary goal of this Special Issue was to present recent trends in surface inspection and description, from both metrological and tribological points of view [...

Optimization of use-wear detection and characterization on stone tool surfaces.

Debates and doubt around the interpretation of use-wear on stone tools called for the development of quantitative analysis of surfaces to complement the qualitative description of traces. Recently, a growing number of studies showed that prehistoric activities can be discriminated thanks to quantitative characterization of stone tools surface alteration due to use. However, stone tool surfaces are microscopically very heterogeneous and the calculated parameters may highly vary depending on the areas selected for measurement.

Pop-In Identification in Nanoindentation Curves with Deep Learning Algorithms.

High-speed nanoindentation rapidly generates large datasets, opening the door for advanced data analysis methods such as the resources available in artificial intelligence. The present study addresses the problem of differentiating load-displacement curves presenting pop-in, slope changes, or instabilities from curves exhibiting a typical loading path in large nanoindentation datasets. Classification of the curves was achieved with a deep learning model, specifically, a convolutional neural network (CNN) model implemented in Python using TensorFlow and Keras libraries.

A Multiscale Topographical Analysis Based on Morphological Information: The HEVC Multiscale Decomposition.

In this paper, we evaluate the effect of scale analysis as well as the filtering process on the performances of an original compressed-domain classifier in the field of material surface topographies classification. Each surface profile is multiscale analyzed by using a Gaussian Filter analyzing method to be decomposed into three multiscale filtered image types: Low-pass (LP), Band-pass (BP), and High-pass (HP) filtered versions, respectively. The complete set of filtered image data constitutes the collected database.

Digital Cultural Heritage Preservation in Art Painting: A Surface Roughness Approach to the Brush Strokes.

There is a growing interest in cultural heritage preservation. The notion of HyperHeritage highlights the creation of new means of communication for the perception and data processing in cultural heritage. This article presents the Digital Surface HyperHeritage approach, an academic project to identify the topography of art painting surfaces at the scale at which the elementary information of sensorial rendering is contained.

Topographical curvature is sufficient to control epithelium elongation.

How biophysical cues can control tissue morphogenesis is a central question in biology and for the development of efficient tissue engineering strategies. Recent data suggest that specific topographies such as grooves and ridges can trigger anisotropic tissue growth. However, the specific contribution of biologically relevant topographical features such as cell-scale curvature is still unclear.

Quantification of the Morphological Signature of Roping Based on Multiscale Analysis and Autocorrelation Function Description.

Roping or ridging is a visual defect affecting the surface of ferritic stainless steels, assessed using visual inspection of the surfaces. The aim of this study was to quantify the morphological signature of roping to link roughness results with five levels of roping identified with visual inspection. First, the multiscale analysis of roughness showed that the texture aspect ratio S computed with a low-pass filter of 32 µm gave a clear separation between the acceptable levels of roping and the non-acceptable levels (rejected sheets).

Determination of an Objective Criterion for the Assessment of the Feasibility of an Instrumented Indentation Test on Rough Surfaces.

The influence of roughness on the results of indentation testing was investigated using a semianalytical model. This model used simulated surfaces that were described using three standard roughness parameters: the root-mean-square deviation S, the wavelength (or cut-off of Gaussian high-pass filter), and the fractal dimension. It was shown that S had the largest effect on the determination of the macrohardness, while the surface wavelength and fractal dimension had negligible effects at the scale of investigation.

How to Select 2D and 3D Roughness Parameters at Their Relevant Scales by the Analysis of Covariance.

In this paper, a multi-scale methodology is proposed to model and characterize the effect of two lubricants on changes in surface morphology during a running-in test. The test concerns two steels samples, mounted on a twin-disc tribometer to test each of lubricants A and B for a period of 42 h. The changes are characterized by the standardized roughness parameters given in ISO 25178.

Surface Reflectance: an Optical Method for Multiscale Curvature Characterization of Wear on Ceramic-Metal Composites.

Surface gradient characterization by light reflectance (SGCLR) is used for the first time for multiscale curvature calculations and discrimination of worn surfaces on six damaged ceramic-metal composites. Measurements are made using reflectance transformation imaging (RTI). Slope and curvature maps, generated from RTI, are analyzed instead of heights.

Surface Texturization of Breast Implants Impacts Extracellular Matrix and Inflammatory Gene Expression in Asymptomatic Capsules.

Background: Texturing processes have been designed to improve biocompatibility and mechanical anchoring of breast implants. However, a high degree of texturing has been associated with severe abnormalities. In this study, the authors aimed to determine whether implant surface topography could also affect physiology of asymptomatic capsules.

A Biophysical Model for Curvature-Guided Cell Migration.

The latest experiments have shown that adherent cells can migrate according to cell-scale curvature variations via a process called curvotaxis. Despite identification of key cellular factors, a clear understanding of the mechanism is lacking. We employ a mechanical model featuring a detailed description of the cytoskeleton filament networks, the viscous cytosol, the cell adhesion dynamics, and the nucleus.

Curvotaxis directs cell migration through cell-scale curvature landscapes.

Cells have evolved multiple mechanisms to apprehend and adapt finely to their environment. Here we report a new cellular ability, which we term "curvotaxis" that enables the cells to respond to cell-scale curvature variations, a ubiquitous trait of cellular biotopes. We develop ultra-smooth sinusoidal surfaces presenting modulations of curvature in all directions, and monitor cell behavior on these topographic landscapes.

Effect of Substrate Temperature on Pattern Formation of Bidispersed Particles from Volatile Drops.

In this study, pattern formation during evaporation of bidispersed drops (containing 1 and 3.2 μm particles) placed on a smooth substrate at different temperatures is investigated. Five distinctive deposition patterns are observed depending on the substrate temperature: a relatively uniform pattern enclosed by a disk-shaped ring, a nearly nonuniform pattern inside a thick outer ring, a "dual-ring" pattern, a "rose-like" pattern, and a set of concentric rings corresponding to the "stick-slip" pattern.

Evaporation of Binary Sessile Drops: Infrared and Acoustic Methods To Track Alcohol Concentration at the Interface and on the Surface.

Evaporation of droplets of three pure liquids (water, 1-butanol, and ethanol) and four binary solutions (5 wt % 1-butanol-water-based solution and 5, 25, and 50 wt % ethanol-water-based solutions) deposited on hydrophobic silicon was investigated. A drop shape analyzer was used to measure the contact angle, diameter, and volume of the droplets. An infrared camera was used for infrared thermal mapping of the droplet's surface.

Characterization of Breast Implant Surfaces, Shapes, and Biomechanics: A Comparison of High Cohesive Anatomically Shaped Textured Silicone, Breast Implants from Three Different Manufacturers.

Unlabelled: Several companies offer anatomically shaped breast implants but differences among manufacturers are often misunderstood. The shell texture is a crucial parameter for anatomically shaped implants to prevent rotation and to decrease the risk of capsular contracture, even though concerns have recently been raised concerning the complications associated with textured breast implants. The aim of this study was to characterize differences in terms of texture, cell adhesion, shape, and stiffness between some commonly used anatomically shaped implants from three different manufacturers.

Correlation modeling between process condition of sandblasting and surface texture: A multi-scale approach.

In the present study, the influence of sandblasting condition (working pressure) on surface texture is modeled, relying on a multi-scale approach and statistical analysis. To improve the correlation modeling between the process condition and surface texture, special effort is made to identification of an optimal parameter set, including 3D roughness parameters, cut-off lengths, filter types and model types. A power law relationship is identified between the pressure and Sdq computed with a cut-off length of 120 µm using a low-pass filter.

Different surface sensing of the cell body and nucleus in healthy primary cells and in a cancerous cell line on nanogrooves.

Cancer cells are known to have alterations compared to healthy cells, but can these differences extend to the way cells interact with their environment? Here, the authors focused on the alignment on an array of grooves of nanometer depth using two cell types: healthy osteoprogenitor primary cells (HOP) and a cancerous osteosarcoma (SaOs-2) cell line. Another concern was how this alignment affects the cell's interior, namely, the nucleus. Based on the results, it is proposed that these two cell types respond to different size regimes: SaOs-2 cells are more sensitive to shallow grooves while HOP cells are strongly aligned with deep grooves.

Effect of substrate temperature on pattern formation of nanoparticles from volatile drops.

This study investigates pattern formation during evaporation of water-based nanofluid sessile droplets placed on a smooth silicon surface at various temperatures. An infrared thermography technique was employed to observe the temperature distribution along the air-liquid interface of evaporating droplets. In addition, an optical interferometry technique is used to quantify and characterize the deposited patterns.

Relevance of roughness parameters of surface finish in precision hard turning.

Precision hard turning is a process to improve the surface integrity of functional surfaces. Machining experiments are carried out on hardened AISI 52100 bearing steel under dry condition using c-BN cutting tools. A full factorial experimental design is used to characterize the effect of cutting parameters.