Characterization Of Surface Topography Research Articles

Evaluation of usage-induced degradation of different endodontic file systems

To evaluate structural profiles and mechanical behaviour of WaveOne Gold (WOG), Twisted File Adaptive (TFA) and XP-endo shaper (XPS) instruments after root canal preparation. Standardized in vitro shaping was performed in presence of 5.25% sodium hypochlorite. File morphology was analyzed using scanning electron microscopy; X-ray diffraction analysis was performed before and after use along with Raman spectroscopy. Nanoindentation was carried out to characterize surface topography. Ni2+ release was measured at 1, 3, 5 and 7 days. X-ray photoelectron spectroscopy (XPS) analysis was done before and after use. After allocating scan line shifts like in WOG, mechanical deformation was shown using first order polynomials. XPS file system showed minimal grooves on surface. SEM of WOG instrument showed scraping surface defects. Hardness varied from 8.11 ± 0.99 GPa in TFA system to 6.7 ± 1.27 GPa and 4.06 ± 4.1 GPa in XPS and WOG. Ni2+ concentration from WOG was 171.2 μg/L. Raman peak at 540–545 cm−1 is attributed to Cr2O3. High resolution of Ti 2p spectrum show distinctive peaks with binding energies dominating in WOG, XPS and TFA file system. XRD exhibited NiTi phases with diffraction peaks. WOG files showed more surface deterioration and less passive layer formation as compared to TFA and XPS systems.

Characterization of Machined Surface Topography Based on the Normal Declination Angle of Microfacets.

It is important to characterize surface topography in order to study machined surface characteristics. Due to the features of periodicity and randomness of machined surface topography, the existing topographical parameters may not describe its features accurately. A novel characterization method called the normal declination angle of microfacet-based surface topography is thus proposed for this task. The topography of machined surfaces is measured and the data on the normal declination angle are obtained. Then, surface topography is analyzed via the distribution of the normal declination angle. The lognormal distribution characterization model of machined surface topography is established, and the accuracy of the model is verified by error analysis. The results show that the calculated results of the present characterization model are generally consistent with the distribution of the normal declination angle, where the maximal root mean square errors (RMSE) is 4.5%. Therefore, this study may serve as an effective and novel way to describe the characteristics of the machined surface topography.

Inference on errors in industrial parts: Kriging and variogram versus geometrical product specifications standard

AbstractThis article focuses on the inference on the errors in manufactured parts controlled by using measurements devices. The characterization of the part surface topographies is core in several applications. A broad set of properties (tribological, optical, biological, mechanical, etc.) depends on the micro‐ and macrogeometry of the parts. Moreover, parts usually show typical deterministic geometric deviation pattern, referred to as manufacturing signatures, due to the specific manufacturing processes and process setup parameters adopted for their production. In several situations, the measurements may also be affected by systematic errors due to the measurement process, that might be caused, for example, by a poor part alignment during the measurement process. Measurement techniques and characterization methods have been standardized in the International Standard ISO 25178, defining parameters characterizing the surface topography and supplying methods and formula adapt to deal with this issue computationally. In the present article, we consider a type of spatial dependence between measured values at different points that suggest the use of the variogram to identify patterns in the parts. We offer a comparison, based on a real set of measures, between the latter approach and the conventional as a test of the efficient performance of our findings.

Feature-based characterisation of surface topography and its application

This keynote paper gives an overview of emerging technologies of feature-based characterisation, for surface topographies having features. It is complementary to conventional surface characterisation using texture field parameters. An original concept, the feature spectrum is proposed to organise surfaces, in order to help select the appropriate characterisation for different types of surface topographies and to achieve a more direct relationship between characterisation, manufacturing process and surface function. The keynote paper focuses on fundamentals and the state of the art for feature-based characterisation technologies. Applications of feature-based characterisation are illustrated and discussed. Guidelines for future industrial applications are laid out, and considerations for future challenges are addressed.Surfaces, Micro structure, Feature-based Characterisation.

Design of Industrial Standards for the Calibration of Optical Microscopes.

One of the most important fields of study in material science is surface characterization. This topic is currently a field of growing interest as many functional properties depend on the surface texture. In this paper the authors, after a short a review of different methods for surface topography characterization and the determination of the traceability problems that arise in this type of measurements, propose four different designs of material standards that can be used to calibrate the most common optical measuring instruments used for these tasks, such as measuring microscopes, metallurgical microscopes, confocal microscopes, focus variation microscopes, etc. The authors consider that the use of this type of standards (or others similar to them) could provide a step forward in assuring metrological traceability for different metrological characteristics that enables a more precise measurement of surface features with optical measuring instruments. In addition, authors expect that this work could lay the groundwork for the development of custom standards with specialized features tuned to gain a better metrological control when measuring specific geometrical surface properties.

Assessment of the classification ability of parameters characterizing surface topography formed in manufacturing and operation processes

The new parameters for the parametric assessment of differentiating the features of surfaces formed in different machining processes was presented in the paper. Classification capacity indicators were analyzed and their interdependencies were presented proposing multi-criteria indicators. Eighty three parameters characterizing geometrical features were determined for 22 surfaces formed in various abrasive and erosive machining processes, as well as for surfaces with different wear conditions. The set of surfaces analyzed was a pattern with a high degree of diversity in the geometric structure of the surfaces studied, but with a similar range of ordinates. In the case of the analyzed surfaces, the functional parameters S5p, S10z, height parameters Sp and Sv as well as new parameters regarding surface elevation features indicate a high ability to distinguish characteristic surface features.Advantages of applying various criteria and aggregating the results of the obtained classification ability assessments for individual parameters have been demonstrated. The test results can be the basis for choosing the parameters forming a complementary set used to assess the suitability of the surface for specific applications. The new parameters of surface topography assessment, useful in assessing contact areas of cooperating surfaces was also presented.

Surface roughness prediction with new barrel-shape mills considering runout: Modelling and validation

Complex aeronautic components such as impellers and blade disks require barrel-end mills having complex geometries to reproduce freeform surfaces. On these parts, the specified surface quality has a key role in wear resistance, ductility and fatigue strength. So, controlling surface roughness is a key factor in the machining process. This work proposes two approaches: 1) a geometrical model of the surfaces being created when using barrel-end mills. It is based on simulating the marks left by the tool on the machined surface; 2) empirical models for a surface prediction based on the cutting parameters. Both approaches were applied to the milling of aluminum Al7075T6 and titanium Ti6Al4V alloys. The experimental roughness was obtained by measuring the surface roughness at the center of the shell-form geometry left by the tool. In general, results show a good agreement between predicted and measured surface roughness for both materials and both approaches. Results lead to relative errors below 15% (geometry-based model) and 10% (empirical models) in most cases. While mathematical models are more accurate, a good basis was obtained with the geometrical model for a more complete 3D characterization of surface topographies using these tools.

Paraffin as a material for optical diffusers – Fabrication and characterization

We present the fabrication and characterization data of an optical diffuser based on paraffin thin films. Surface topography and optical characterization results are described. Such films can be used in either reflection or transmission mode. Their specific surface features allow for combination of random refraction and diffraction to take place, offering enhanced light diffusion.

Effect of Gelation Temperature on the Molecular Structure and Physicochemical Properties of the Curdlan Matrix: Spectroscopic and Microscopic Analyses.

In order to determine the effect of different gelation temperatures (80 °C and 90 °C) on the structural arrangements in 1,3-β-d-glucan (curdlan) matrices, spectroscopic and microscopic approaches were chosen. Attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) and Raman spectroscopy are well-established techniques that enable the identification of functional groups in organic molecules based on their vibration modes. X-ray photoelectron spectroscopy (XPS) is a quantitative analytical method utilized in the surface study, which provided information about the elemental and chemical composition with high surface sensitivity. Contact angle goniometer was applied to evaluate surface wettability and surface free energy of the matrices. In turn, the surface topography characterization was obtained with the use of atomic force microscopy (AFM) and scanning electron microscopy (SEM). Described techniques may facilitate the optimization, modification, and design of manufacturing processes (such as the temperature of gelation in the case of the studied 1,3-β-d-glucan) of the organic polysaccharide matrices so as to obtain biomaterials with desired characteristics and wide range of biomedical applications, e.g., entrapment of drugs or production of biomaterials for tissue regeneration. This study shows that the 1,3-β-d-glucan polymer sample gelled at 80 °C has a distinctly different structure than the matrix gelled at 90 °C.

HIGH-PRECISION RANGING BASED ON MULTISPECTRAL FULL-WAVEFORM LIDAR

Abstract. Full-waveform light detection and ranging (LiDAR) has become a well-established technique for remote sensing of surface topography and target characterization, offering numerous opportunities in investigation and interpretation of the structural diversity of surface coverage. However, most prevailing waveform decomposition methods employ the Gaussian function or some other probability distributions to model LiDAR waveforms of specific shapes, which cannot be universally used. Moreover, most of these waveform decomposition methods operate at a single laser wavelength and cannot be applied well to multispectral LiDAR (MSL) or hyperspectral LiDAR (HSL), which can simultaneously collect the spectral and geometric attributes with multiple transmitting laser wavelengths. In this paper, we propose a new multispectral B-spline waveform decomposition model to achieve high precision multi-target ranging. Considering both the spatial consistency of each channel and the irregular shape of the received waveform, LiDAR waveforms are modelled by B-splines rather than any other specific probability distribution. Thus, the proposed method can be extended to other FWMSL data benefiting from the flexibility of B-splines on fitting arbitrary curves. Both simulated MSL echoes and a measured dataset from a FWMSL system with three wavelengths of 556, 670, and 780 nm were used in this study. Compared with two single wavelength waveform decomposition models and a multispectral waveform decomposition model based on Gaussian function, the proposed method has excellent robustness for processing different shapes of waveforms and can improve ranging accuracy significantly for irregular waveforms.

Peri-implant soft tissue integration in humans – influence of materials: A study protocol for a randomised controlled trial and a pilot study results

BackgroundRecently, there has been a growing interest in mucointegration as the formation of an early and long-standing soft tissue barrier seems essential for both the initial healing and long-term implant survival. AimTo develop an experimental method to characterize the mucointegration of different transgingival materials (titanium (Ti), polyetheretherketone (PEEK), polymethylmethacrylate (PMMA), zirconia (Zi), polymer infiltrated ceramic network (PICN), cobalt-chrome (Co–Cr), and lithium disilicate (LD)) in a human model. MethodsThe study is designed as a multi-part randomized controlled clinical trial. Ninety bone level Straumann implants will randomly receive an experimental, custom-made abutment to allow for the removal of the abutment together with the surrounding soft tissues using a punch biopsy device at 8 weeks of healing (10 per material). The specimens will be further processed for non‐decalcified histology, followed by histomorphometric analysis. The same protocol will be used for additional 90 implants-abutments, but during harvesting, soft tissues will be separated from the abutment and processed for immunohistochemistry in order to study tissue inflammation and vascularization, while the abutments will undergo SEM analysis. Additionally, in vitro analyses, including SEM and profilometry, will be performed in order to characterize surface topography of all experimental materials. ConclusionThe limited number of pilot samples presented herein indicate that the use of custom-made abutments in humans is a reproducible method to study peri-implant soft tissue integration. This further intensifies the rationale to compare different abutment materials, used as transgingival components in daily practice, under the same conditions.

Sdq-Sdr Topological Map of Surface Topographies

The reliable characterization of surface topographies – especially in case of tribological processes – requires complex and comprehensive solution methods. The use of a combination of roughness parameters offers effective solutions in many cases. In our study, we found a close correlation between the Sdq-Sdr parameter pair and we applied the two parameters as a topological map. Surface topographies resulting from different machining techniques (turned, milled, ground, honed, electric discharge machined, and sintered) were placed in the topological map and their possibilities of use were explored. It was established that surfaces with an orientation characteristically have lower Sdq-Sdr value pairs than non-oriented or multi-oriented surfaces; however, surface defects, injuries and machining discrepancies increase the values of Sdq-Sdr parameters. Then the Sdq-Sdr topological map was applied for worn surfaces resulting from abrasive and tribochemical processes, and it was established that the worn surfaces examined are characterized by small Sdq-Sdr values. Test results showed that in case of manufacturing processes, the topological map is suitable for identifying manufacturing discrepancies and manufacturing defects, and it highlights structural changes in the microgeometry in the course of the wear process.

Synthesis and Self-Healing Mechanism of Self-Healing Epoxy Microcapsule Materials

Self-healing epoxy resin microcapsules are prepared by interfacial polymerization, in which the core materials are epoxy resin, the wall materials are constructed with triethylenetetramine and the epoxy resin. The orthogonal experimental L9(34) are designed to investigate the influence of emulsifier dosage, hardener dosage, curing temperature and hardener adding rate on the core content and storage life of epoxy resin microcapsule. Scanning electron microscope is used to characterize surface topography and distribution. Fourier transform infrared spectroscopy is used to study reaction mechanism of the microcapsule wall materials, respectively. The results indicate that when the dosage of emulsifier is 1.2%, the dosage of hardener is 1.2%, the hardener droplets adding rate is 1.2 g/h and the curing temperature is 50°C, the prepared microcapsules with a high level of core content are spherical in shape with good surface compactness and dispersibility. Future research may focus on improving microcapsule storage stability and the obstacles encountered in practical applications.

Diamond nanocrystal thin films: Case study on surface texture and power spectral density properties

Analyzing diamond nanocrystal (DNC) thin film morphology produced by the HFCVD technique is the main objective of the present work. Stereometric analysis of three-dimensional surface microtextures was carried out based on data obtained through atomic force microscopy (AFM), while the ISO 25178-2:2012 standard was applied to characterize surface topography. The Abbott–Firestone curve, peak count histograms, and Cartesian graphs, which were extracted through AFM images, gave valuable statistical information. As can be seen, the most isotropic sample was the Au catalyst (etched) deposited by the hot filament chemical vapor deposition method. Moreover, by increasing the time of DNC growth from 15 min to 60 min, the surface roughness was increased. In addition, the average power spectral density was calculated and furrows were determined for all samples.

Application of Clustering Filter for Noise and Outlier Suppression in Optical Measurement of Structured Surfaces

In comparison to tactile sensors, optical techniques can provide a fast, nondestructive profile/areal surface measurement solution. Nonetheless, high measurement noise, unmeasured points, and outliers are often observed in optical measurement, particularly for structured surfaces. To alleviate their detrimental impacts on the characterization of surface topography as well as the examination of micro/nanoscale geometries, a post processing filtering technique, i.e., the clustering filter, which is essentially an iterative process to find the aggregation center of a cluster of points, is implemented. The clustering filter is particularly useful for noises and outlier suppression for optical measurement of structured surfaces due to its edge-preserving capability. Five surface samples with structured features are measured by an in-house developed dispersive interferometer and a commercial white light interferometer, thereafter the measured surface data are filtered by the clustering filter. Both noise and outliers are suppressed, which not only facilitates the visualization and characterization of surface topography, but also enables the accurate evaluation of local functional geometries.

Surface modification of albumin/gelatin films gelled on low‐temperature plasma‐treated polyethylene terephthalate plates

AbstractAlbumin/gelatin gel (AG) properties are studied with an innovative cold‐plasma‐treatment‐based technique. Gel films are produced in situ on polyethylene terephthalate (PET) plates previously treated by gas (O2, air and Ar) cold plasma. After detaching the films from the surface, the contact angles of probe liquids are measured and wettability studied, based upon the induced changes of AG surface free energy. The effect of gelatin concentration in the AG is analysed. Oxygen‐cold‐plasma‐treated PET plates induce outstanding changes in wetting properties. Optical profilometry is used for the characterisation of surface topography. Dynamic oscillatory measurements help check for mesoscopic changes. The latter technique allows shaping of gel sample stiffness. The findings support a new methodology for biomaterials/biopolymer activation when unable to be exposed to the plasma working conditions.

Comparison and validation of surface topography segmentation methods for feature-based characterisation of metal powder bed fusion surfaces

Feature-based characterisation, i.e. the characterisation of surface topography based on the isolation of relevant topographic formations (features) and their dimensional assessment, is a developing field of surface texture metrology. Feature-based approaches provide dimensional assessments of individual features (area, width, height, etc) as well as statistical properties of feature aggregations (e.g. mean, standard deviation, etc), which may be more intuitive or related to functionality. For powder bed fusion surfaces, a commonly investigated feature of interest is the particles or spatter present on the surface. In this work, we address segmentation, a necessary step of feature-based characterisation, where the measured surface topography is spatially partitioned into regions to isolate the targeted features from their surroundings. Three topography segmentation methods are investigated: morphological segmentation on edges, contour stability analysis and active contours. To perform the comparison, three powder bed fusion surfaces obtained at differing build orientations (0°, 30° and 90°) and measured using focus variation microscopy are subjected to the three segmentation approaches - optimised to isolate spatter and particles on the surface. The comparison of the segmentation methods focuses on performance in feature identification (i.e. the capability to correctly detect the presence of features) and performance in feature boundary determination (i.e. the capability to correctly trace the boundaries of each feature). Results show that no segmentation method is consistently superior for all test cases, but the comparison approach is useful to explore and optimise segmentation alternatives for feature-based characterisation scenarios.

Ensemble Neural Networks for Modeling DEM Error

Digital elevation models (DEMs) have become ubiquitous and remarkably effective in the field of earth sciences as a tool to characterize surface topography. All DEMs have a degree of inherent error and uncertainty that is propagated to subsequent models and analyses, which can lead to misinterpretation and inaccurate estimates. A new method was developed to estimate local DEM errors and implement corrections while quantifying the uncertainties of the implemented corrections. The method is based on the flexibility and ability to model complex problems with ensemble neural networks (ENNs). The method was developed to be applied to any DEM created from a corresponding set of elevation points (point cloud) and a set of ground truth measurements. The method was developed and tested using hyperspatial resolution terrestrial laser scanning (TLS) data (sub-centimeter point spacing) collected from a marsh site located along the southern portion of the Texas Gulf Coast, USA. ENNs improve the overall DEM accuracy in the study area by 68% for six model inputs and by 75% for 12 model inputs corresponding to root mean square errors (RMSEs) of 0.056 and 0.045 m, respectively. The 12-input model provides more accurate tolerance interval estimates, particularly for vegetated areas. The accuracy of the method is confirmed based on an independent data set. Although the method still underestimates the 95% tolerance interval, 8% below the 95% target, results show that it is able to quantify the spatial variability in uncertainties due to a relationship between vegetation/land cover and accuracy of the DEM for the study area. There are still opportunities and challenges in improving and confirming the applicability of this method for different study sites and data sets.

Effect of Surface Topography Parameters on Friction and Wear of Random Rough Surface.

In order to explore the relationship between the surface topography parameters and friction properties of a rough contact interface under fluid dynamic pressure lubrication conditions, friction experiments were carried out. The three-dimensional surface topography of specimens was measured and characterized with a profile microscopy measuring system and scanning electron microscope. The friction coefficient showed a trend of decreasing first and then increasing with the increase in some surface topography parameters at lower pressure, such as the surface height arithmetic mean Sa, surface height distribution kurtosis Sku, surface volume average volume Vvv, and surface center area average void volume Vvc, which are the ISO 25178 international standard parameters. The effects of surface topographic parameters on friction were analyzed and the wear mechanism of the worn surface was presented. The wear characteristics of the samples were mainly characterized as strain fatigue, grinding, and scraping. The results provide a theoretical basis for the functional characterization of surface topography.

Structural, Surface Topography and Optical Characterization of Nanocrystalline MgxZn1-xO Thin Films Grown by Modified Chemical Bath Deposition (SILAR) Method

A series of MgxZn1-xO thin films were grown on glass substrates using modified chemical bath deposition (m-CBD) called successive ionic layer adsorption and reaction (SILAR) technique. The crystal structure, surface topography and the optical characterization of the prepared films were studied as a function of Mg/Zn (x) content. It is observed that the deposited films have polycrystalline structure in nature and grown in two phases Hexagonal and cubic. The preferential orientation of the films was absorbed along (002) plane. Structural parameter such as crystallite size, number of dislocation density and micro-strain were also investigated. The crystallite size and surface roughness are increased with the increase of Mg2+ ions content. Thus the results showed that the surface topography and the surface quality of the deposited films can be controlled by Mg2+ ions content. The optical transmittance spectra analysis showed that transmittance increase with the increase Mg2+ content to about 85% for x = 0.75, and the energy band gap increases (2.82 - 3.17) eV as the Mg2+ content increases x = (0.25 - 0.75). These results indicate that the MgxZn1-xO thin films can be potentially used in high-performance ultraviolet optoelectronic devices.