Roughness Patterns Research Articles

Digitized Seedbed Soil Quality Assessment from Worn and Edge Hardened Cultivator Sweeps.

Tillage tools for seedbed soil management are often subjected to low stress abrasion wear, which could negatively affect seedbed quality and crop productivity. Limited studies exist that quantify the effects of worn tillage tools on seedbed quality and crop yield. This research investigated the influence of tillage tool wear on seedbed preparation by evaluating the effect of cultivator sweep wear on soil tilth utilizing a light detection and ranging (LiDAR) sensor. The framework consists of a seedbed tillage field experiment using a Completely Randomized Design (CRD) experiment in six replicates of two-tillage treatments (new and worn cultivator sweeps). After seedbed tillage, loosely tilled soil aggregates were removed to expose the seedbed soil profile, and then seedbed roughness statistical measures were estimated from LiDAR-scanned seedbed soil surface. Three statistical analyses (Analysis of Variance (ANOVA), Kolmogorov-Smirnov (KS), and Earth Mover's Distance (EMD)) were compared to quantitatively evaluate the soil roughness estimated from the LiDAR seedbed surface data. Seedbed prepared by new and worn cultivator sweeps showed significant differences (p < 0.05) in soil roughness variables of standard deviation, coefficient of variation, and kurtosis. Data analysis from the ANOVA and KS methods revealed that LiDAR-extracted soil roughness patterns were statistically influenced by tillage treatment. EMD analysis detected noticeable disparities between the tillage treatments and new versus worn cultivator sweeps. This study concludes that tillage tool wear substantively affects seedbed quality, as evidenced by LiDAR soil profile estimated attributes of soil roughness and three statistical methods (ANOVA, KS, and EMD). Our study supports the adoption of LiDAR technology for seedbed management, highlighting its applicability to evaluate seedbed quality that accounts for the wear life cycle of cultivator sweeps.

Synthesis of engineering surfaces using representative elementary patterns of roughness

Synthesis of surface roughness is a long-standing problem that has many practical applications. Here novel algorithms for the synthesis of rough surfaces at nano/micro scales are proposed. The algorithms are based on introduction and development of two new concepts, namely the representative elementary pattern of roughness (REPR) and the statistically representative pattern of surface roughness (SRPSR). From the statistical point of view, the REPR is the smallest interval (or area) over which a measurement can be made that represents statistically the whole surface. However, synthesis of surfaces by the direct use of the REPR may cause some artificial singularities. To avoid this drawback and to incorporate the synthetic surface in a numerical scheme of the contact solver, one needs to extend the REPR to a non-singular SRPSR that satisfies additional conditions of the scheme used. Our findings indicate that specific time-series analysis techniques, such as the moving window approach, can be effectively utilized to extract the REPR from experimental data. The representativeness may be justified by the use of the Kolmogorov–Smirnov statistic. Extraction of REPRs of surfaces and constructions of appropriate SRPSRs are demonstrated on experimental data obtained by stylus and atomic-force microscopy at micro and atomic/nano scales, respectively.

Performance of surface roughness of MHD slip velocity on curved circular and flat plates lubricated with non-Newtonian fluid

The current communication aims to discuss the influence of MHD slip velocity on curved circular and rough flat plate under the non-Newtonian fluid is considered. MHD momentum equation is reduced to ordinary differential equation and solved analytically. Christenson Stochastic theory is used to derive the radial and azimuthal surface roughness expression. From the Stochastic theory we derived non dimensional Reynolds equation also mathematical derivations for squeeze film pressure, load and squeezing time are derived analytically. Applied numerical method to illustrate pressure, load support & response time graphically. In contrast to the smooth case, the load-carrying capacity and response time for azimuthal (radial) roughness patterns are affected by the roughness parameter. Also the impact of MHD couple stress with slip velocity provides the rise of squeeze film attributes than the case of non-magnetic, Newtonian and smaller values of slip velocity.

Carapace Morphology Variations in Captive Tortoises: Insights from Three-Dimensional Analysis.

The carapace morphology of tortoises is a crucial characteristic used for species identification, with features such as shell shape, roughness, and color patterns varying among species. Understanding this morphological diversity is valuable not only for taxonomic classification but also for more specialized clinical approaches. This study investigated the morphological differences in the shells of Leopard tortoises (Stigmochelys pardalis), African spurred tortoises (Centrochelys sulcata), and Greek tortoises (spur-thighed tortoises; Testudo graeca) raised in captivity. Using 3D scanners, the carapaces were modeled, and a 3D geometric morphometric method was employed to analyze shape variations and dimensional features, with landmarks applied automatically. Among the species studied, African spurred tortoises had the largest carapace size. Principal component analysis (PCA) identified PC1 and PC3 as critical factors in distinguishing between species based on morphological characteristics. Positive PC1 values, associated with a shorter carapace height, indicated a flatter or more compact shell shape. A higher PC3 value corresponded to a raised shape at the back of the shell, while a lower PC3 value indicated a raised shape at the front. Specifically, Leopard tortoises exhibited a higher carapace shape than the other species, while African spurred tortoises had shorter carapaces. An allometric effect was observed in the carapaces, where smaller specimens tended to be proportionately higher-domed, whereas larger shells displayed a lower height in shape. These findings highlight the significance of shape variations in tortoise shells, which emerge during adaptation and have important implications for taxonomy and clinical practice. Such differences should be carefully considered in veterinary care and species identification.

An experimental investigation on surface integrity and wire wear in rough and trim cut modes of WEDM for hybrid composite

PurposeThe purpose of this paper is to investigate the surface integrity features, including surface roughness (SR), recast layer (RL), material migration, topography and wire wear pattern in rough and trim-cut wire electric discharge machine (WEDM) of hybrid composite (Al6061-90%/SiC-2.5%/TiB2-7.5%).Design/methodology/approachEffects of four important factors, namely, rough-cut history (RCH), pulse on time (Ton), peak current (IP) and wire offset (WO) have been assessed on the responses of interest for trim-cut WEDM. Box–Behnken design (RSM) was used to formulate the experimentation plan. Quantitative indices of surface integrity, namely, SR and RL, and selected samples have been investigated for qualitative analysis, namely, surface topography, material migration and wire wear pattern.FindingsTon and IP are found to be most significant, whereas RCH and WO are found insignificant for SR. Ton and WO were found to be the most significant factors affecting RL. After trim cut, an RL of thickness 8.26 µm is observed if the initial rough cut has been accomplished at high discharge energy setting. Whereas the best value of RL thickness, i.e. 5.36 µm, can be realized with low level of RCH. A significant decrease in the presence of foreign materials is recorded, indicating its strong correlation with the discharge energy used during machining.Originality/valueInvestigation on surface integrity features for machining of hybrid composite through rough and trim-cut WEDM has been reported by only a limited number of researchers in the past. This study is attempted at fulfilling few vital gaps by addressing the issues such as evaluation of the efficacy of trim cutting under different discharge energy conditions (using RCH), analysis of wire wear pattern in both rough and trim-cut modes and investigation of the wire breakage phenomenon during machining.

Photocatalytic and antibacterial activity properties of Ti surface treated by femtosecond laser–a prospective solution to peri-implant disease

Laser texturing seems to be a promising technique for reducing bacterial adhesion on titanium implant surfaces. This work aims to demonstrate the possibility of obtaining a functionally orientated surface of titanium implant elements with a specific architecture with specific bacteriological and photocatalytic properties. Femtosecond laser-generated surface structures, such as laser-induced periodic surface structures (LIPSS, wrinkles), grooves, and spikes on titanium, have been characterised by XRD, Raman spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of the titanium surfaces produced was tested based on the degradation effect of methylene blue (MB). The correlation between the photocatalytic activity of TiO2 coatings and their morphology and structure has been analysed. Features related to the size, shape, and distribution of the roughness patterns were found to influence the adhesion of the bacterial strain on different surfaces. On the laser-structurised surface, the adhesion of Escherichia coli bacteria were reduced by 80% compared to an untreated reference surface.

Influence of 3D joint roughness on fracture behaviours of rock mass subjected to compression

Jointed rock mass with internal rough structural planes have a significant influence on the mechanical behaviour and damage mode of the rock mass. Based on the Weierstrass-Mandelbrot (W-M) fractal function, a numerical model containing a single rough fracture was established. Multi-parameters sensitivity analysis was carried out to determine the key parameters affecting the mechanical properties. By conducting experimental research on the single fracture inclination, fractal dimension, and surface precision of numerical model uniaxial compression, the influence laws of different parameters and the model cracking process were revealed. The results show that the cracks go through the process of sprouting from the single fracture and expanding to both sides, and the expansion of shear cracks in the structural plane reflects the roughness pattern of the structural plane. The higher the roughness was, the lower the peak uniaxial compression strength of the model was. The change of the parameters influenced the macroscopic cracking morphology of the model, and the model finally showed the destruction along the diagonal, the V-shaped destruction, the X-like destruction, and the X-type destruction. The results have an outstanding reference value for further researches on the application of three-dimensional rough discrete fracture networks.

Geological Mapping of Kaso, Tambaksari, Ciamis, West Java Province Using Lidar Images Interpretation

Abstract Remote sensing nowadays is used to quickly and effectively obtain information about an object, area or phenomenon and can be applied to large areas that are sometimes difficult to reach. Satellites with multispectral imagery are commonly used in geological mapping, but have drawbacks when used in tropical areas such as Indonesia, with dense vegetation, fast sedimentation rates and highly weathered that will cover fresh rocks making it difficult to interpret geological condition through aerial photo. Light Detection And Ranging (LiDAR) images using laser beams to produce elevation data (x,y,z) with high spatial resolution and can penetrate the surface of vegetation are expected to be a solution in areas with dense vegetation that are sometimes difficult to reach. The study was conducted by interpreting the morphometric aspects using Digital Terrain Model (DTM) data processed from LiDAR imagery with a spatial resolution of 1 m/pixel to display the topographical surface in detail. The morphometric aspects used include slope, surface roughness, aspect, hillshade, and stream pattern. Field data validation through surface mapping is carried out to correct the lithology interpretation by comparing the results of LiDAR image interpretation. Field data validation results show that interpretation using LiDAR imagery has good results (79%) through overall accuracy percentage, with the lithology units being sandstones, siltstone, breccias, and andesitic igneous rocks. The lineament interpretation of the DTM data indicates the existence of a geological structure in the form of a normal and strike-slip fault in the study area.

Erosive Effect of Canned Juices and Soft Drinks on Surface Roughness of Restorative Materials Used in Pediatric Dentistry: An Ex Vivo Study.

To evaluate and compare the effect of fruit juice (orange) and cola drink (noncarbonated) on the surface texture of composite (3M ESPE Filtek Bulk Fill) and glass ionomer cement (GIC) (ChemFil Superior). A total of eighty pellets each were prepared with composite (3M ESPE Filtek Bulk Fill) and GIC (ChemFil Superior) material using a brass mold with an inner diameter of 3 mm and a thickness of 3 mm according to the manufacturer's instructions. Around 10 pellets of each material were placed in airtight plastic containers. The baseline surface texture value was obtained by profilometer. An 8-day immersion regime was carried out according to Maupome et al. After the 8-day test period, pellets were reevaluated for surface texture final value. The values were statistically analyzed. A statistically significant lower surface roughness of composite restorative material was observed when treated with high-concentration orange juice and medium-concentration. Conversely, a statistically significant lower surface roughness of GIC restorative material was observed when it was treated with the low-concentration group, high-concentration orange juice, and medium-concentration orange juice. The surface roughness patterns of restorative materials increased as the number of immersion regimes increased. Vishwanathaiah S, Maganur PC, Khabrany HM, et al. Erosive Effect of Canned Juices and Soft Drinks on Surface Roughness of Restorative Materials Used in Pediatric Dentistry: An Ex Vivo Study. Int J Clin Pediatr Dent 2024;17(7):807-811.

A Multiscale Statistical Analysis of Rough Surfaces and Applications to Tribology

Mathematical modelling of surface roughness is of significant interest for a variety of modern applications, including, but not limited to, tribology and optics. The most popular approaches to modelling rough surfaces are reviewed and critically examined. By providing counterexamples, it is shown that approaches based solely on the use of the fractal geometry or power spectral density have many drawbacks. It is recommended to avoid these approaches. It is argued that the surfaces that cannot be distinguished from the original rough surfaces can be synthesised by employing the concept of the representative elementary pattern of roughness (REPR), i.e., the smallest interval (or area) of a rough surface that statistically represents the whole surface. The REPR may be extracted from surface measurement data by the use of the “moving window” technique in combination with the Kolmogorov–Smirnov statistic.

Diverse material properties and morphology of moth proboscises relates to the feeding habits of some macromoth and other lepidopteran lineages.

Insects have evolved unique structures that host a diversity of material and mechanical properties, and the mouthparts (proboscis) of butterflies and moths (Lepidoptera) are no exception. Here, we examined proboscis morphology and material properties from several previously unstudied moth lineages to determine if they relate to flower visiting and non-flower visiting feeding habits. Scanning electron microscopy and three-dimensional imaging were used to study proboscis morphology and assess surface roughness patterns on the galeal surface, respectively. Confocal laser scanning microscopy was used to study patterns of cuticular autofluorescence, which was quantified with colour analysis software. We found that moth proboscises display similar autofluorescent signals and morphological patterns in relation to feeding habits to those previously described for flower and non-flower visiting butterflies. The distal region of proboscises of non-flower visitors is brush-like for augmented capillarity and exhibited blue autofluorescence, indicating the possible presence of resilin and increased flexibility. Flower visitors have smoother proboscises and show red autofluorescence, an indicator of high sclerotization, which is adaptive for floral tube entry. We propose the lepidopteran proboscis as a model structure for understanding how insects have evolved a suite of morphological and material adaptations to overcome the challenges of acquiring fluids from diverse sources.

Quantitative coarse graining of laminar fluid flow penetration in rough boundaries

The interaction between a fluid and a wall is described with a certain boundary condition for the fluid velocity at the wall. To understand how fluids behave near a rough wall in a completely laminar flow regime, the fluid velocity at every point on the rough surface may be provided. This approach requires detailed knowledge of, and likely depends strongly on the roughness. Another approach of modelling the boundary conditions of a rough wall is to coarse grain and extract a penetration depth over which on average the fluid penetrates into the roughness. In this work, we examine the impact of well-defined patterned surfaces on the fluid flow behaviour. We considered two extreme cases: one with horizontal ridges and another with vertical ridges on the wall and an intermediate case with ridges at an angle on the wall. We show that for a broad range of periodic roughness patterns and relative flow velocities, a universal penetration depth function can be obtained. We obtain these results with experiments and complementary numerical simulations. We evaluate how this penetration depth depends on the various roughness parameters such as ridge depth, ridge spacing and ridge angle. Our results present a novel approach to investigating wall roughness boundary conditions by considering the penetration depth δ that captures the spatially averaged behaviour of the decaying velocity profile between the asperities. We find that this penetration depth δ can be rescaled into a simple exponential master curve δ = δ∞(1 − e−kD/S) for horizontal ridges with varying depth D and spacing S. A similar variation of δ with D and S is observed for vertical ridges, but with a smaller magnitude δ∞, while for ridges at an angle, the penetration depth lies between the two extreme cases.

Fabrication of micro/submicron hierarchical structures on ceramic sheet surfaces combining 2-step imprinting and in-plane compression processes

Many organisms have functional microstructured surfaces. Particularly, lotus leaves have hierarchical dual-scale micro/nanostructures on their surface and exhibit highly water repellent properties. We have developed techniques to fabricate patterns on inorganic material surfaces such as ceramics. Applying these techniques to fabricate hierarchical structures can make ceramic surfaces even more promising. In this paper, we prepared 2 kinds of mold with line-and-space patterns with pitches 50 μm and 2 μm and fabricated micro (rough patterns)/submicron (fine patterns) hierarchical structures on sintered ceramic sheets using a newly developed imprinting process with in-plain compression method. We proposed processes for the fabrication of such hierarchical structures, discussed the possibility of higher resolution of the patterns by comparison with the analytical results.

The effect of pulsed Er,Cr:YSGG laser scanning on the adhesion strength of lithium disilicate to tooth dentin

This study examined how Er,Cr:YSGG laser surface conditioning affected the adhesion of lithium disilicate ceramic to the dentin tooth structure. Forty samples were divided into four groups (n=10). The first group was untreated, whereas the second was etched with hydrofluoric acid. The third group was treated for 2 minutes with a 7 W, 25 Hz Er,Cr:YSGG laser. The fourth group received the same Er,Cr:YSGG laser treatment at 5 W. The untreated group had the lowest shear bond scores. Laser-irradiated Group 3 at 7 W had a higher maximum shear bond strength than the hydrofluoric acid-etched group. The laser-irradiated groups also had a more uniform, non-invasive surface roughness pattern. The samples were tested by atomic force microscopy, scanning electron microscopy, and a universal shear bond testing machine. Surface treatment with the Er,Cr:YSSG laser at 7 W improves lithium disilicate ceramic adhesion to dentin. The laser outperforms hydrofluoric acid as the gold standard.

Experimental investigation of surface roughness/wettability pattern effect on crystallization fouling over falling-film flow

In many industries, including desalination, scaling in heat exchangers is a persistent issue, and most methods of scaling control involve environmentally hazardous chemical additives. Exploiting the effects of surface features and flow-imposed shear on salt deposition might introduce a new approach to scale management, opening the possibility of self-cleaning surfaces. In this work, we experimentally explore surface roughness and wettability patterns interaction with salt deposition and flow shear. Heat transfer and scale mass deposition on flat surfaces are measured during thin-film evaporation of calcium sulfate solution. A wide range of surface roughness (0.027–2.66 μm) is studied at fixed flow and heat flux conditions. Due to improved mixing, heat transfer is enhanced with rougher surfaces initially; however, degrades more quickly than smoother surfaces. Following a period of initial mass deposition fluctuation, a steady scaling stage is observed, with rough surfaces scaling more than smooth surfaces. Wettability patterned surfaces can suppress crystal nucleation without sacrificing overall surface wetting, resulting in antifouling performance and heat transfer enhancement. Scale mass deposition on a patterned surface is reduced by 60 %, and 27 % heat transfer improvement over the baseline surface is found. This study provides guidance to surface manipulation for heat transfer improvement and fouling mitigation.

Ultrathin Feldspathic Ceramic Veneers: A Pilot SEM Evaluation of Etched Intaglio Surfaces.

Ultrathin ceramic veneers are a viable therapeutic option to manage esthetic challenges in the anterior zone. Proper conditioning of the intaglio surface of porcelain veneers is essential to achieve an adequate bonding. In clinical practice, this is typically done with chemical etching using an acid-containing agent, such as hydrofluoric acid. While it is well established that the etching effect is dependent on etching time and the acid concentration, little is known about the impact of etching time and the veneer fabrication method. The purpose of this pilot study was to evaluate, using scanning electron microscopy (SEM), the effect that different etching-time protocols have on the intaglio surface characteristics of ultrathin ceramic veneers fabricated with either the platinum foil technique or the refractory die technique. Several replicas of an ultrathin feldspathic ceramic veneer for a maxillary central incisor were fabricated. Individual specimens were processed according to different intaglio surface-etching protocols: no etching, etching for 90 seconds, etching for 120 seconds, and etching for 150 seconds (9.6% hydrofluoric acid used for all etching groups). It was observed that the 120-second etching protocol resulted in a favorable microroughness surface pattern in the platinum foil group. This pattern was comparable to that obtained by etching for 90 seconds with hydrofluoric acid the intaglio surface of veneers fabricated with the refractory die technique. Increasing the etching time to 150 seconds did not result in a more favorable roughness pattern.

Semi-analytical approach-based studies of the squeeze film lubrication between rough porous annular discs: Rabinowitsch fluid model

In recent years, there has been much interest in the effects of porosity and surface roughness (SR) or geometric irregularities between two moving plates under hydrodynamic lubrication. Porous bearings are used extensively in wide range of equipment, including computers, office equipment, home appliances, electric motors, and vehicles. In light of the importance of the aforementioned applications, we explored how SR and porous materials affect annular discs under the condition of a squeeze film. A five-point Gauss quadrature integral formula has been used to examine the characteristics of annular discs and a small perturbation method has been used to discretise the governing Rabinowitsch fluid flow (RFF) equations. The impact of nonlinear parameters on the behaviour of porosity and SR have been visualised in terms of film pressure (FP), load carrying capacity (LCC), and squeeze response time (SRT) of annular discs. Under the conditions of pseudoplastic and dilatant fluids, the effects of SR and porous materials between annular discs have been estimated in the form of the film pressure, LCC, and SRT and are presented in this manuscript as tables and graphs. According to the findings, the performance of an annular disc is significantly affected by porous material and radial roughness patterns. In addition, when RFF is carried through a rough surface and porous media, the performance is found to improve for dilatant fluids but suffer for pseudoplastic fluids.

Magnetohydrodynamics and viscosity variation in couple stress squeeze film lubrication between rough flat and curved circular plates

A simplified mathematical model has been developed for understanding combined effects of surface roughness, viscosity variation and couple stresses on the squeeze film behaviour of a flat and a curved circular plate in the presence of transverse magnetic field. The Stokes (1966) couple stress fluid model is included to account for the couple stresses arising due to the presence of microstructure additives in the lubricant. In the context of Christensen’s (1969) stochastic theory for the lubrication of rough surfaces, two types of one-dimensional roughness patterns (radial and azimuthal) are considered. The governing modified stochastic Reynolds type equations are derived for these roughness patterns. Expressions for the mean squeeze film characteristics are obtained. Numerical computations of the results show that the azimuthal roughness pattern on the curved circular and flat plate results in more pressure buildup whereas performance of the squeeze film suffers due to the radial roughness pattern. Further the Lorentz force characterized by the Hartmann number, couple stress parameter and viscosity variation parameter improve the performance of the squeeze film lubrication as compared to the classical case (Non-magnetic, Newtonian case and non-viscous case).

Performance of rough secant slider bearing lubricated with couple stress fluid in the presence of magnetic field

The effect of surface roughness, magnetic field, and couple stress on the performance of secant slider bearing is studied in this paper. The effectiveness of the bearing is assessed by using a couple stress liquid as the lubricant in the process. Because of microstructural impacts, couple stress fluids have distinctive rheological characteristics. These features have the potential to make a major impact on the bearing’s performance. The novel aspect of this study is that the roughness of the secant slider is taken into consideration. The modified Reynolds equation is derived using Christensen’s stochastic theory for roughness. Here, both transverse and longitudinal roughness patterns are considered. The analytical solutions are obtained for steady-state pressure, load-carrying capacity, film stiffness, and damping coefficient. The results are presented for various parameters through graphs and tables. The combined effect of the magnetic field and couple stress is significant on bearing characteristics. It is noticed that the bearing features increase with the longitudinal roughness parameter, and the reverse phenomenon is observed with the transverse roughness parameter. When a transverse roughness pattern is assumed on a secant slider bearing, characteristics like pressure, load, stiffness of the film, and damping coefficient increase significantly.

Surface morphological evolution and microhardness change of Cr12MoV steel by pulsed laser polishing

Laser polishing is gaining more and more attention because of its environmental friendliness and ability to process complex surfaces. It is considered as one of the technologies to replace traditional methods in the mold industry. In this work, the variation pattern of surface roughness with single pulse energy density and light-out overlap rate during nanosecond pulsed laser polishing of Cr12MoV steel was investigated. The surface roughness increased and then decreased with increasing single-pulse energy density and beam overlap rate, respectively. The lowest surface roughness was found to be 0.50 μm, which is a decrease of 79.34 % compared to the untreated sample. The effect of each parameter on the surface morphology during the laser polishing process is explained. There is minimal austenitization on the surface of the sample after laser polishing. The second phase of the remelting layer disappeared. The microhardness of the remelting layer increased by 36.17 % because the grain size was reduced by 30.65 %. This work further explains the mechanism transformation threshold for pulsed laser polishing of steel. With 95 % beam overlap, the melting and gasification energy density thresholds for Cr12MoV steel are respectively 1.269 J/cm2 and 2.937 J/cm2. The beam overlap rate of 95.5 % is the critical condition for continuous melt movement. It provides a new idea for the mechanism judgment of pulsed laser polishing.