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1
Yun, Yong Il, Il Young Park, and Seung Jin Song. "Performance Degradation due to Blade Surface Roughness in a Single-Stage Axial Turbine." Journal of Turbomachinery 127, no. 1 (2005): 137–43. http://dx.doi.org/10.1115/1.1811097.
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Turbine blades experience significant surface degradation with service. Previous studies indicate that an order-of-magnitude or greater increase in roughness height is typical, and these elevated levels of surface roughness significantly influence turbine efficiency and heat transfer. This paper presents measurement and a mean-line analysis of turbine efficiency reduction due to blade surface roughness. Performance tests have been conducted in a low-speed, single-stage, axial flow turbine with roughened blades. Sheets of sandpaper with equivalent sandgrain roughnesses of 106 and 400 μm have been used to roughen the blades. The roughness heights correspond to foreign deposits on real turbine blades measured by Bons et al. [1]. In the transitionally rough regime (106 μm), normalized efficiency decreases by approximately 4% with either roughened stator or roughened rotor and by 8% with roughness on both the stator and rotor blades. In the fully rough regime (400 μm), normalized efficiency decreases by 2% with roughness on the pressure side and by 6% with roughness on the suction side. Also, the normalized efficiency decreases by 11% with roughness only on stator vanes, 8% with roughness only on rotor blades, and 19% with roughness on both the stator and rotor blades.
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Craig, Michael, Jay Raval, Bruce Tai, Albert Patterson, and Wayne Hung. "Effect of Channel Roughness on Micro-Droplet Distribution in Internal Minimum Quantity Lubrication." Dynamics 2, no. 4 (2022): 336–55. http://dx.doi.org/10.3390/dynamics2040019.
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This research studied the effect of channel roughness on micro-droplet distributions in internal minimum quantity lubrication for effective machining. Mixtures of different oils and air were flown though internal channels with simulated different roughness: as fabricated, partially threaded, and fully threaded. The airborne droplets were collected, analyzed, and compared with simulated results by computational fluid dynamics. For low-viscous lubricant, the rough channel surface helped to break large droplets in the boundary layer into smaller droplets and reintroduce them into the main downstream flow. The opposite trend was found for the higher viscous lubricant. The study also performed chemical etching to roughen selected surfaces of carbide cutting tools. The synergy of hand and ultrasonic agitation successfully roughened a carbide surface within twelve minutes. Scanning electron microscopy examination showed deep etching that removed all grinding marks on a WC–Co cutting tool surface.
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Kheur, Mohit, Tabrez Lakha, Saleha Shaikh, et al. "A Comparative Study on Simulated Chairside Grinding and Polishing of Monolithic Zirconia." Materials 15, no. 6 (2022): 2202. http://dx.doi.org/10.3390/ma15062202.
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This study evaluated the effects of different simulated chairside grinding and polishing protocols on the physical and mechanical properties of surface roughness, hardness, and flexural strength of monolithic zirconia. Sintered monolithic zirconia specimens (15 mm × 3 mm × 3 mm) were abraded using three different burs: diamond bur, modified diamond bur (zirconia specified), and tungsten carbide bur, along with a group of unprepared specimens that served as a control group. The study was divided into two phases, Phase 1 and Phase 2. Surface roughness, surface hardness, and flexural strength were assessed before and after the grinding procedure to determine the ‘best test group’ in Phase 1. The best abrasive agent was selected for Phase 2 of the study. The specimens in Phase 2 underwent grinding with the best abrasive agent selected. Following the grinding, the specimens were then polished using commercially available diamond polishing paste, a porcelain polishing kit, and an indigenously developed low-temperature sintered zirconia slurry. The physical and mechanical properties were again assessed. Results were analyzed using one-way ANOVA test. Specimens were observed under scanning electron microscopy (SEM) and X-ray diffraction (XRD) for their microstructure and crystalline phases, respectively. Grinding with diamond burs did not weaken zirconia (p > 0.05) but produced rougher surfaces than the control group (p < 0.05). Tungsten carbide burs did not significantly roughen the zirconia surface. However, specimens ground by tungsten carbide burs had a significantly reduced mean flexural strength (p < 0.05) and SEM revealed fine surface cracks. Phase transformation was not detected by XRD. Polishing with commercially available polishing agents, however, restored the surface roughness levels to the control group. Dental monolithic zirconia ground with tungsten carbide burs had a significantly reduced flexural strength and a smooth but defective surface. However, grinding with diamond burs roughened the zirconia surface. These defects may be reduced by polishing with commercially available polishing agents. The use of tungsten carbide burs for grinding dental zirconia should not be advocated. Grinding with diamond abrasives does not weaken zirconia but requires further polishing with commercially available polishing agents.
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Wang, Jun, Jose Antonio Sánchez, Borja Izquierdo, and Izaro Ayesta. "Influence of AISI D2 Workpiece Roughness on Heat Partition and Plasma Channel Radius in the WEDM Process." Metals 10, no. 10 (2020): 1360. http://dx.doi.org/10.3390/met10101360.
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As an important advanced machining process, in Wire Electrical Discharge Machining (WEDM) certain fundamental issues remain need to be studied in-depth, such as the effect of part surface roughness on heat transfer mechanisms. In the WEDM process, roughing cut wire goes into the workpiece to do the first shaping and in trim cut the wire sweeps on the outer surface to improve the surface roughness. In both of these two cases, the generation of sparks depends on the passing surface roughness. Therefore, with AISI D2 material and brass wire, this paper presents a study of the influence of part surface roughness on heat partition and the radius of the plasma channel in the WEDM process. Through extensive single discharge experiments, it is shown that the removal capacity per discharge can increase if the discharge occurs on a smoother surface. A Finite Element thermal model was then used for inverse fitting of the values of heat partition and radius of the plasma channel. These parameters completely define the characteristics of the heat conduction problem. The results indicate a strong correlation between an increase in heat partition ratio and a decrease in part surface roughness. The values of plasma channel radius show an increase in this value when discharging on rougher surfaces. It means that with the increasing of plasma channel radius, the heat source goes into the workpiece more dispersed. In the case of rougher surface, although the there is more area that affected by the heat source, finally the temperature of most area cannot reach to the melting point and it causes the smaller crater radius and volume, while the metal removal rate decreases. These results contribute towards a more complete understanding of the influence of surface roughness to the spark occurring.
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Mulleners, K., P. Gilge, and S. Hohenstein. "Impact of Surface Roughness on the Turbulent Wake Flow of a Turbine Blade." Journal of Aerodynamics 2014 (December 30, 2014): 1–9. http://dx.doi.org/10.1155/2014/458757.
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Roughened aeroengine blade surfaces lead to increased friction losses and reduced efficiency of the individual blades. The surface roughness also affects the wake flow of the blade and thus the inflow conditions for the subsequent compressor or turbine stage. To investigate the impact of surface roughness on a turbulent blade wake, we conducted velocity field measurements by means of stereo particle image velocimetry in the wake of a roughened turbine blade in a linear cascade wind tunnel. The turbine blade was roughened at different chordwise locations. The influence of the chordwise location of the added surface roughness was examined by comparing their impact on the width and depth of the wake and, the positions and distribution of vortical structures in the wake. Additionally, the friction loss coefficients for different surface roughness positions were estimated directly from the velocity field.
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XIAO, BOQI, YIDAN ZHANG, YAN WANG, et al. "A FRACTAL MODEL FOR KOZENY–CARMAN CONSTANT AND DIMENSIONLESS PERMEABILITY OF FIBROUS POROUS MEDIA WITH ROUGHENED SURFACES." Fractals 27, no. 07 (2019): 1950116. http://dx.doi.org/10.1142/s0218348x19501160.
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In this paper, fluid transport through fibrous porous media is studied by the fractal theory with a focus on the effect of surface roughness of capillaries. A fractal model for Kozeny–Carman (KC) constant and dimensionless permeability of fibrous porous media with roughened surfaces is derived. The determined KC constant and dimensionless permeability of fibrous porous media with roughened surfaces are in good agreement with available experimental data and existing models reported in the literature. It is found that the KC constant of fibrous porous media with roughened surfaces increases with the increase of relative roughness, porosity, area fractal dimension of pore and tortuosity fractal dimension, respectively. Besides, it is seen that the dimensionless permeability of fibrous porous media with roughened surfaces decreases with increasing relative roughness and tortuosity fractal dimension. However, it is observed that the dimensionless permeability of fibrous porous media with roughened surfaces increases with porosity. With the proposed fractal model, the physical mechanisms of fluids transport through fibrous porous media are better elucidated.
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Jemat, Afida, Mariyam Jameelah Ghazali, Masfueh Razali, and Yuichi Otsuka. "Effects of Surface Treatment on Titanium Alloys Substrate by Acid Etching for Dental Implant." Materials Science Forum 819 (June 2015): 347–52. http://dx.doi.org/10.4028/www.scientific.net/msf.819.347.
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Many studies were carried out to investigate the ability of titanium alloys for dental implant. Surface treatment is one of the famous methods to increase the titanium surface properties. The purpose of this paper is to investigate the effects of acid etching on the surface topography and roughness of titanium alloys (Ti6Al4V ASTM 1472-99). Acid etchings were carried out by using different type of acids with same time exposures. All etched surface were characterized by using an X-ray diffraction (XRD), a scanning electron microscope (SEM) and a roughness tester. Acid etched and pure surface were comparatively analysed. Results obtained show that the type of acids influenced the surface topography as well as roughness properties. The microstructure of the surface is highly modified after acid etching. Further we can confirm that, the experimental etched titanium alloys had features of a roughened surface with micro-roughness. In general, the experimental surface (0.137 μm – 3.986 μm) was significantly rougher than control surface (0.124 μm).
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Alaskari, Ayman M., Abdulaziz I. Albannai, Meshal Y. Alawadhi, Abdulkareem S. Aloraier, Tatiana Liptakova, and Abdullah A. Alazemi. "Surface Evaluation of a Multi-Pass Flexible Magnetic Burnishing Brush for Rough and Soft Ground 60/40 Brass." Materials 13, no. 19 (2020): 4465. http://dx.doi.org/10.3390/ma13194465.
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Burnishing is an advanced finishing process that produces higher-quality surfaces with better hardness and roughness than conventional finishing processes. Herein, a flexible magnetic burnishing brush comprising stainless steel pins under permanent magnet poles was used to investigate the influence of multiple passes and directions on the produced surface of soft and rough ground prepared brass. In total, five different samples were burnished on each of the two brass samples prepared. Four samples were processed in the same direction for up to four passes and the fifth sample was processed with two passes in the opposite direction. Results indicate that there was approximately a 30% increase in hardness and an 83% increase in microroughness for rougher-surface brass samples. For smoothly prepared surfaces, there was approximately a 14% increase in hardness and a 35% increase in microroughness. In the same direction of multi-pass burnishing, increasing the number of passes negatively affected surface roughness; for rougher surfaces, the surface hardness reduced and process uniformity increased owing to surface over-hardening and flaking mechanisms, and for smoother surfaces, the hardness, roughness, and process non-uniformity increased with the number of passes owing to repeated surface deformation at some locations and high flaking at other locations. Compared to single-pass burnishing, wherein the surface roughness and microhardness showed almost no change with high process uniformity, in burnishing with two opposite-direction passes, the produced surface exhibited better surface roughness, process uniformity, and microhardness improvements owing to a reverse strain mechanism. Hence, opposite burnishing passes are recommended.
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Taslim, M. E., L. Setayeshgar, and S. D. Spring. "An Experimental Evaluation of Advanced Leading Edge Impingement Cooling Concepts." Journal of Turbomachinery 123, no. 1 (2000): 147–53. http://dx.doi.org/10.1115/1.1331537.
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The main objective of this experimental investigation was to measure the convective heat transfer coefficient of impingement for different target wall roughness geometries of an airfoil leading edge, for jet to wall spacings and exit flow schemes. Available data in the open literature apply mostly to impingement on flat or curved smooth surfaces. This investigation covered two relatively new features in blade leading-edge cooling concepts: curved and roughened target surfaces. Experimental results are presented for four test sections representing the leading-edge cooling cavity with cross-over jets impinging on: (1) a smooth wall, (2) a wall with high surface roughness, (3) a wall roughened with conical bumps, and (4) a wall roughened with tapered radial ribs. The tests were run for two supply and three exit flow arrangements and a range of jet Reynolds numbers. The major conclusions of this study were: (a) There is a heat transfer enhancement benefit in roughening the target surface; (b) while the surface roughness increases the impingement heat transfer coefficient, the driving factor in heat transfer enhancement is the increase in surface area; (c) among the four tested surface geometries, the conical bumps produced the highest heat transfer enhancement.
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Li, Biying, Tairan Fu, and Congling Shi. "Correlations between High-Temperature Oxidation Kinetics and Thermal Radiation Characteristics of Micro-Structured Nickel Surfaces Oxidized at 1173 K." Metals 9, no. 1 (2018): 17. http://dx.doi.org/10.3390/met9010017.
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Micro-structured surface functional materials were widely used in electronics, batteries, solar cells, and many other products. However, oxidation at high temperatures greatly affects the material service life and performance. This study focuses on the oxide layer characteristics after high-temperature oxidation and the thermal emissivity of metal materials with micro-structured surfaces. Micro-structured surfaces with various groove morphologies were prepared on 99.9% purity nickel samples. The high-temperature oxidation characteristics of the nickel samples with the microstructure surfaces and the total hemispherical emissivities were measured after various oxidation times in high-temperature (1173 K) air to characterize the correlations between the micro-structure surface oxidization and the emissivity at elevated temperatures. The initial surface roughness greatly affects the surface roughness after oxidation with the oxidation increasing the surface roughness on smooth or less rough surfaces but making the surface smoother for very rough surfaces. The oxidation results show that rougher initial surfaces have larger oxide grain sizes with longer oxidation times leading to smaller grain sizes. The measured total hemispherical emissivity increased with the temperature (500–1400 K) and the oxide layer thickness. The experiments further illustrates that, for the same oxide layer thickness, the measured emissivities become larger for oxides with larger grain sizes caused by the rougher original surfaces. This analysis provides an understanding of the oxidation kinetics of microstructured surfaces and how the oxidized microstructure surfaces affect the thermal radiation properties.
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Bhushan, Bharat, and Kristian To̸nder. "Roughness-Induced Shear- and Squeeze-Film Effects in Magnetic Recording—Part II: Applications." Journal of Tribology 111, no. 2 (1989): 228–37. http://dx.doi.org/10.1115/1.3261893.
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Surface roughness-induced hydrodynamic gas lubrication theory including rarefaction effects is used to explain the effects of surface roughness on the magnetic head-medium spacing. Since video-recording operates at h/σ (film thickness/standard deviations of composite roughness) ≤ 3, the spacing increases with the roughness because the head surface remains at the distance on the order of 3σ from the mean of the tape surface. Data processing tapes operate at h/σ ≥ 4, and the increase in spacing with the roughness is found to be due to roughness-induced squeeze films. Squeeze motion can be generated by the isolated high asperities on the tape surface and bearing load variations due to a moving roughness (in shear flow) which are expected to increase with an increase in the surface roughness, and modulations of surfaces from other instabilities. Increase in signal-to-noise ratio and in amplitude variation for a rougher tape is also explained by the surface roughness variations. Influence of surface roughness on the head-disk spacing is also analyzed. Recommendations are made for an optimum roughness orientation and magnitude and whether the roughness should lie on the stationary or moving surfaces.
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Salami, Daniele, and Maria Aparecida Alves de Cerqueira Luz. "Effect of prophylactic treatments on the superficial roughness of dental tissues and of two esthetic restorative materials." Pesquisa Odontológica Brasileira 17, no. 1 (2003): 63–68. http://dx.doi.org/10.1590/s1517-74912003000100012.
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Dental prophylaxis is a common way to remove dental plaque and stain, both undesirable factors in most dentistry procedures. However, besides cleaning the tooth surface, prophylactic techniques may increase the surface roughness of restorations and dental tissues, which, in turn, may result in plaque accumulation, superficial staining and superficial degradation. This study evaluated the effect of three prophylactic techniques - sodium bicarbonate jet, pumice paste and whiting paste - on the superficial roughness of two restorative materials - a composite resin and a compomer - and on the superficial roughness of two dental surfaces - enamel and cementum/dentin - through rugosimetric and scanning electron microscopy (SEM) analysis. Statistical analysis of the rugosimetric data showed that the use of pumice paste on enamel produced a significantly smoother surface than the natural surface. However, comparing the effect of the three techniques, prophylaxis with the pumice paste produced a rougher surface than did the other techniques as regards enamel and cementum/dentin probably due to its abrasiveness. On composite resin, the pumice paste only produced a rougher surface than did the whiting paste. On compomer, all of the applied treatments produced similar results. Based on rugosimetric and SEM analysis, we could conclude that the prophylactic treatments employed did not improve roughness of the studied surfaces. As to the effects of the techniques, they were different depending on the surfaces on which the prophylactic treatments were applied.
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Khanna, Himanshu, and Harminder Singh. "Effect of Surface Roughness of Roller Burnishing Process on 20MNCR5 Steel." International Scientific Journal of Engineering and Management 04, no. 03 (2025): 1–6. https://doi.org/10.55041/isjem02318.
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Burnishing process is used to smooth the surface of 20MnCr5 steel. The surface roughness of the steel is influenced by the burnishing parameters such as number of passes, feed, speed, and depth of penetration. The results show that the initial roughness is the most important factor affecting the surface finish. To reduce the roughness, it is necessary to optimize the process parameters. In this paper, the effect of burnished parameters on the surface finishing and wear resistance of the mechanical components is investigated. Results show that burnishing process parameters have a significant impact on surface finish, yield strength, fatigue resistance, wear resistance, surface hardness, tensile strength and corrosion resistance. The ANOVA table shows that the interaction between no. of passes and feed, feed and deep of penetration, condition is significant towards surface roughing. The percentage contribution pie chart indicates that the condition is contributing maximum up to 38%, speed is contributing up to 9 % whereas Depth of penetration and feed have least contribution in surface roughened steel. Keywords surface roughness ,burnishing, steel
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Zhong, Zhao-Wei. "Surface roughness of machined wood and advanced engineering materials and its prediction: A review." Advances in Mechanical Engineering 13, no. 5 (2021): 168781402110176. http://dx.doi.org/10.1177/16878140211017632.
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This article discusses the surface roughness of wood and advanced engineering materials after machining and its prediction. The topics are surface roughness of precision-machined advanced engineering materials, machining of WC and Inconel, rapidly solidified Al alloys, surface roughness of wood materials, and prediction of surface roughness. Findings include that ductile streaks on silicon and glass surfaces ground or lapped with inexpensive machines largely reduced the polishing time to obtain the required surface roughness. Abrasive jet machining could remove the patterns from recycled wafers and improve the surface roughness. The roughness of WC-Co coatings was significantly improved by using the method of fast regime fluidized bed machining. As beryllium is a toxic element, the rapidly solidified Al alloy may be a good insert material to replace BeCu. Higher bonding strengths resulted from rougher surfaces of wood samples. Wood samples had reduced bonding strengths after soaking in water. Optimum artificial neural networks (ANNs) with necessary inputs could accurately predict the roughness values. ANNs trained using particle swarm optimization and genetic algorithms could predict surface roughness better than typical ANNs. Minimum quantity lubrication is a hot research topic to minimize the amount of the fluid for cost and environmental considerations.
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Tang, Yiwei, Nianwei Dai, Jun Wu, Yiming Jiang, and Jin Li. "Effect of Surface Roughness on Pitting Corrosion of 2205 Duplex Stainless Steel Investigated by Electrochemical Noise Measurements." Materials 12, no. 5 (2019): 738. http://dx.doi.org/10.3390/ma12050738.
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The influence of surface roughness on the pitting corrosion behaviour of 2205 duplex stainless steel (DSS) in a chloride-containing environment was investigated using electrochemical noise (EN) techniques and morphology observation. A rougher surface condition increased the frequency of pit initiation because of the increase in more occluded pit sites. Rough surface finish also accelerated pit growth by increasing the actual dissolution rate in the pit. Metastable pits on rougher surfaces had longer lifetimes and grew to larger sizes, as their inner chemical environment was more easily maintained. However back-scatter images showed that pitting initiates on DSS 2205 regardless of the roughness condition.
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Grosfils, Patrick, and James F. Lutsko. "Impact of Surface Roughness on Crystal Nucleation." Crystals 11, no. 1 (2020): 4. http://dx.doi.org/10.3390/cryst11010004.
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We examine the effect of rough surfaces on crystal nucleation by means of kinetic Monte Carlo simulations. Our work makes use of three-dimensional kMC models, explicit representation of transport in solution and rough surfaces modeled as randomly varying height fluctuations (roughness) with exponentially decaying correlation length (topology). We use Forward-Flux Sampling to determine the nucleation rate for crystallization for surfaces of different roughness and topology and show that the effect on crystallization is a complex interplay between the two. For surfaces with low roughness, small clusters form on the surface but as clusters become larger they are increasingly likely to be found in the bulk solution while rougher surfaces eventually favor heterogeneous nucleation on the surface. In both cases, the rough surface raises the local supersaturation in the solution thus leading to another mechanism of enhanced nucleation rate.
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Teng, Fu-Yuan, Chia-Ling Ko, Hsien-Nan Kuo, et al. "A Comparison of Epithelial Cells, Fibroblasts, and Osteoblasts in Dental Implant Titanium Topographies." Bioinorganic Chemistry and Applications 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/687291.
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The major challenge for dental implants is achieving optimal esthetic appearance and a concept to fulfill this criterion is evaluated. The key to an esthetically pleasing appearance lies in the properly manage the soft tissue profile around dental implants. A novel implant restoration technique on the surface was proposed as a way to augment both soft- and hard-tissue profiles at potential implant sites. Different levels of roughness can be attained by sandblasting and acid etching, and a tetracalcium phosphate was used to supply the ions. In particular, the early stage attaching and repopulating abilities of bone cell osteoblasts (MC3T3-E1), fibroblasts (NIH 3T3), and epithelial cells (XB-2) were evaluated. The results showed that XB-2 cell adhesive qualities of a smooth surface were better than those of the roughened surfaces, the proliferative properties were reversed. The effects of roughness on the characteristics of 3T3 cells were opposite to the result for XB-2 cells. E1 proliferative ability did not differ with any statistical significance. These results suggest that a rougher surface which provided calcium and phosphate ions have the ability to enhance the proliferation of osteoblast and the inhibition of fibroblast growth that enhance implant success ratios.
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Soler, Daniel, Martín Telleria, M. Belén García-Blanco, Elixabete Espinosa, Mikel Cuesta, and Pedro José Arrazola. "Prediction of Surface Roughness of SLM Built Parts after Finishing Processes Using an Artificial Neural Network." Journal of Manufacturing and Materials Processing 6, no. 4 (2022): 82. http://dx.doi.org/10.3390/jmmp6040082.
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A known problem of additive manufactured parts is their poor surface quality, which influences product performance. There are different surface treatments to improve surface quality: blasting is commonly employed to improve mechanical properties and reduce surface roughness, and electropolishing to clean shot peened surfaces and improve the surface roughness. However, the final surface roughness is conditioned by multiple parameters related to these techniques. This paper presents a prediction model of surface roughness (Ra) using an Artificial Neural Network considering two parameters of the SLM manufacturing process and seven blasting and electropolishing processes. This model is proven to be in agreement with 429 experimental results. Moreover, this model is then used to find the optimal conditions to be applied during the blasting and the electropolishing in order to improve the surface roughness by roughly 60%.
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Schwartz, Z., C. H. Lohmann, J. Oefinger, L. F. Bonewald, D. D. Dean, and B. D. Boyan. "Implant Surface Characteristics Modulate Differentiation Behavior of Cells in the Osteoblastic Lineage." Advances in Dental Research 13, no. 1 (1999): 38–48. http://dx.doi.org/10.1177/08959374990130011301.
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This paper reviews the role of surface roughness in the osteogenic response to implant materials. Cells in the osteoblast lineage respond to roughness in cell-maturation-specific ways, exhibiting surface-dependent morphologies and growth characteristics. MG63 cells, a human osteoblast-like osteosarcoma cell line, respond to increasing surface roughness with decreased proliferation and increased osteoblastic differentiation. Alkaline phosphatase activity and osteocalcin production are increased. Local factor production is also affected; production of both TGF-β1 and PGE2 is increased. On rougher surfaces, MG63 cells exhibit enhanced responsiveness to 1,25-(OH)2D3. Prostaglandins mediate the effects of surface roughness, since indomethacin prevents the increased expression of differentiation markers in these cells.
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Nowak, Wojciech J. "Effect of Surface Roughness on Oxidation Resistance of Stainless Steel AISI 316Ti During Exposure at High Temperature." Journal of Materials Engineering and Performance 29, no. 12 (2020): 8060–69. http://dx.doi.org/10.1007/s11665-020-05267-x.
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AbstractIn the present work, the influence of surface roughness on oxidation kinetics of AISI 316Ti stainless steel and its consequences in term of oxidation resistance were investigated. Namely, the effect of surface roughness on oxidation resistance was evaluated during different types of cyclic oxidation tests at 900 and 1000 °C. The obtained results revealed that alloy possessing higher surface roughness showed longer lifetime compared to that with lower surface roughness. It was also found that more severe cyclic conditions suppressed the positive effect of surface roughness on sample’s lifetime. The better oxidation resistance of rougher alloy was correlated with suppressed formation of Fe-rich nodules on ground surfaces and explained by the combined effect of introduced defects in the near-surface region and possible increase in residual stresses caused by mechanical surface preparation.
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Bennett, Jean M. "Surface Roughness and Scattering." Proceedings of The Manufacturing & Machine Tool Conference 2004.5 (2004): 15–16. http://dx.doi.org/10.1299/jsmemmt.2004.5.15.
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Petersen, Philip G., Lloyd V. Smith, and Derek Nevins. "The effect of surface roughness on oblique bicycle helmet impact tests." Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology 234, no. 4 (2020): 320–27. http://dx.doi.org/10.1177/1754337120917809.
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The friction between a helmet and impact surface affects the accelerations imparted to the head. The roughness of the impact surface is, therefore, a consideration when developing oblique impact standards. An 80-grit abrasive paper is commonly used in oblique impact tests to simulate a road surface, but has not been validated for bicycle impacts and may not accurately represent real road surfaces. In the following study, a helmeted NOCSAE headform with a Hybrid III neck was dropped onto a 45° anvil at 6.5 m/s using a twin wire guided drop tower. Helmeted drops were performed in two orientations (frontal and side) on road surfaces, roughened steel surfaces, 80-grit abrasive paper and a low friction surface. For each impact, measures of linear and rotational acceleration were obtained. These metrics were compared across impact orientations and surfaces to assess the influence of surface roughness on headform impact response. Frontal impacts were less sensitive to the impact surface roughness than side impacts across metrics. Among metrics, rotational acceleration showed the largest effect due to surface roughness. Compared to the road surface, peak rotational acceleration from impacts on the 80-grit surface were 6.5% less and 48% greater for frontal and side impacts, respectively. Based on consideration of the peak and cumulative impact measures, steel impact surfaces appear to better simulate road impact than the commonly used 80-grit abrasive paper.
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Yu, Ning, and Andreas A. Polycarpou. "Combining and Contacting of Two Rough Surfaces with Asymmetric Distribution of Asperity Heights." Journal of Tribology 126, no. 2 (2004): 225–32. http://dx.doi.org/10.1115/1.1614822.
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The statistical approach of describing rough surfaces is extended to include the contact of two rough surfaces in which their distribution of asperity heights can either be symmetric or asymmetric, and the asymmetry is modeled using the normalized Weibull distribution. In considering the contact between two rough surfaces, as in most practical applications, the contact can be approximated by an equivalent rough surface in contact with a smooth plane. The roughness parameters of the equivalent surface are obtained using the spectral moment method, and its validity is verified using realistic surface roughness measurements. This paper presents a method to obtain the equivalent rough surface with a Weibull distribution of asperity heights, in which the standard deviation and skewness parameters of asperity heights of the actual contacting surfaces are preserved. The advantages of this method are demonstrated via direct comparisons with a previously proposed method as well as with exact numerical simulation of the contact parameters of several different actual surfaces from magnetic storage and MEMS applications. For practical engineering applications, where the roughness parameters of each individual surface are known, contour plots for the skewness value of the equivalent rough surface are provided for practical ranges of combinations of standard deviation ratios and skewness values. As expected when the roughness of one of the contacting surfaces dominates, the skewness is solely determined by the rougher surface.
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Lungevics, Janis, Ernests Jansons, and Karlis Agris Gross. "Skeleton Runner Roughness and Surface Contact Area Influence on Sliding Ability: Field Experiments." Key Engineering Materials 800 (April 2019): 303–7. http://dx.doi.org/10.4028/www.scientific.net/kem.800.303.
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Scientists and sport athletes are constantly seeking for the methods which could improve surface sliding ability on ice. Modifications of contact area and surface roughness are relatively easy but not yet fully understood methods for sliding ability improvements. This research contains information of how one can perform on-field experiments with skeleton sleigh to determine the influence of surface contact area and roughness on sliding ability. Two types of surface roughness i.e. polished (3000 grain sandpaper) and scratched (600 grain sandpaper) are compared using three different contact areas. Obtained data showed that rougher surfaces tend to slide faster if contact area is larger but the effect reverses if contact area is reduced.
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Song, Kwanwoo, Jinwook Lee, Seong-O. Choi, and Jooyoun Kim. "Interaction of Surface Energy Components between Solid and Liquid on Wettability, and Its Application to Textile Anti-Wetting Finish." Polymers 11, no. 3 (2019): 498. http://dx.doi.org/10.3390/polym11030498.
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With various options of anti-wetting finish methods, this study intends to provide basic information that can be applied in selecting a relevant anti-wetting chemical to grant protection from spreading of liquids with different surface energy profiles. With such an aim, the anti-wetting effectiveness of fluorinated coating and silane coating was investigated for liquids having different surface energy components, water (WA), methylene iodide (MI) and formamide (FA). The wetting thermodynamics was experimentally investigated by analyzing dispersive and polar component surface energies of solids and liquids. The role of surface roughness in wettability was examined for fibrous nonwoven substrates that have varied surface roughness. The presence of roughness enhanced the anti-wetting performance of the anti-wetting treated surfaces. While the effectiveness of different anti-wetting treatments was varied depending on the liquid polarities, the distinction of different treatments was less apparent for the roughened fibrous surfaces than the film surfaces. This study provides experimental validation of wetting thermodynamics and the practical interpretation of anti-wetting finishing.
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Mohd Foudzi, Farhana, Lai Yu Hung, Fathin Iliana Jamhari, et al. "Physical and Hardness Performance at Different Surfaces for Titanium Alloy (Ti6Al4V) Printed Using Selective Laser Melting Process (SLM)." Jurnal Kejuruteraan 36, no. 3 (2024): 1217–26. http://dx.doi.org/10.17576/jkukm-2024-36(3)-31.
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elective laser melting (SLM) 3D product is capable of producing varied surfaces such as top, core and bottom surface depending on the product dimensions and building orientation. Each surface may have differences in physical and mechanical properties such as surface roughness, microhardness, and microstructure. Therefore, this study examined the effects of SLM processing parameters as well as volumetric energy density (VED) on surface roughness, microhardness and microstructure on different 3D product surfaces. In this study, a sample of titanium alloy cube (Ti6Al4V) with different surfaces of up skin 1 (US1), up skin 2 (US2), core skin (CS) and down skin (DS) are printed on a 30° building orientation printed through the SLM process. There are nine sets of parameters printed based on the Taguchi 𝐿9 experimental design method. All printed cube samples were heat treated to remove the residual stresses generated during the printing process. The effect of processing parameters on micro hardness as well as microstructure on each surface has been studied. This study found that SLM printed Ti6Al4V produced almost identical surface quality for different surfaces of the cubic samples. Surface roughness of US2 ranging between 15.38 µm and 26.22 µm, while DS is slightly rougher with surface roughness in the range of 16.05 µm and 27.64 µm. Microhardness in the nine processing sets however was found to have a bigger difference in values of 387 ± 10 HV (US2) and 362 ± 10 HV (DS). In general, US2 surfaces were found to have high microhardness compared to the DS surfaces due to the formation of long, straight needle-like martensitic microstructure.
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Norafifah, H., M. Y. Noordin, S. Izman, and D. Kurniawan. "Acid Pretreatment of WC-Co for Surface Roughening and Cobalt Removal Prior to CVD Diamond Coating." Applied Mechanics and Materials 315 (April 2013): 592–96. http://dx.doi.org/10.4028/www.scientific.net/amm.315.592.
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Chemical vapor deposition (CVD) diamond coatings are being developed to be applied on carbide cutting tools to enhance wear resistance and increase tool life. As a prerequisite, for ensuring adhesion of CVD diamond on tungsten carbide substrate, it is necessary to prepare high surface roughness and to remove the cobalt on tungsten carbide surface during the pretreatment. In this study, a two step acid pretreatment was examined for those purposes. Etching using modified Murakamis reagent was initially performed to roughen the surface. Subsequently, the carbide was immersed in nitric acid to remove cobalt. Concentration of the acid solutions and reaction time were varied. Results showed that the initial step by modified Murakamis reagent etching resulted in a surface roughness of Ry = 6.95 µm, which is a 15% increase from the average initial surface roughness. The second step by nitric acid immersion on modified Murakamis reagent etched carbide samples resulted in carbide surfaces with zero cobalt content, confirming the effectiveness of the pretreatment.
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Brandt, Bjoern, and Torsten Rabe. "Surface Characteristics of LTCC Substrates Fabricated by Pressure-Assisted Sintering." Journal of Microelectronics and Electronic Packaging 10, no. 4 (2013): 144–49. http://dx.doi.org/10.4071/imaps.385.
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Plane LTCC substrates can be produced in zero-shrinkage technology by pressure-assisted sintering. The application of axial pressure during sintering supports densification, enhances cofiring of different materials, and restrains deformation. However, the sintered surfaces are affected by the release tapes and by the setters used in the pressure-assisted sintering process. In this study, the effect of release tape particle size on the surface properties of sintered substrates was investigated. Moreover, the substitution of release tape by the use of a vitreous carbon setter was tested. Surface roughness and sheet resistances of metallic thin films on the respective samples were determined. It was found that the roughness of the substrates is not directly correlated with the adequacy of the surface for thin-film deposition. Compared with a freely sintered sample with an average roughness (Ra) of 0.31 μm, pressure-assisted sintering created smoother surfaces using fine-grained release tapes (Ra = 0.18 μm) and rougher surfaces using coarse release tapes (Ra = 0.46 mm). Still, sheet resistances were higher on all sinter-pressed samples. The vitreous carbon setter created unusual trenched surface structures, characterized by varying roughness values and intermediate sheet resistances on the LTCCs tested.
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Fenelon, Thomas, Mahmoud M. Bakr, Laurence J. Walsh, and Roy George. "Effects of Lasers and Their Delivery Characteristics on Machined and Micro-Roughened Titanium Dental Implant Surfaces." Bioengineering 7, no. 3 (2020): 93. http://dx.doi.org/10.3390/bioengineering7030093.
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The aim of the study was to investigate the effects of neodymium: yttrium aluminium garnet (Nd:YAG) (1064 nm) and erbium: yttrium aluminium garnet (Er:YAG) (2940 nm) laser energy on titanium when delivered with conventional optics (focusing handpieces or plain ended optical fibres) or with a conical tip. Machined and micro-roughened implant discs were subjected to laser irradiation under a variety of energy settings either dry (without water) or wet (with water). Samples were scanned using a 3D non-contact laser profilometer and analysed for surface roughness, volume of peaks and the maximum diameter of the ablated area. Conical tip designs when used with both lasers showed no surface effect at any power setting on both machined and micro-roughened implant surfaces, regardless of the irrigation condition. When used with conventional delivery systems, laser effects on titanium were dose related, and were more profound with the Nd:YAG than with the Er:YAG laser. High laser pulse energies caused surface fusion which reduced the roughness of micro-roughened titanium surfaces. Likewise, repeated pulses and higher power densities also caused greater surface modifications. The presence of water reduced the influence of laser irradiation on titanium. It may be concluded that conical fibres can reduce unwanted surface modification, and this may be relevant to clinical protocols for debridement or disinfection of titanium dental implants.
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Brandt, Bjoern, and Torsten Rabe. "Surface Characteristics of LTCC Substrates Fabricated by Pressure-assisted Sintering." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2013, CICMT (2013): 000261–67. http://dx.doi.org/10.4071/cicmt-tha42.
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Plane LTCC substrates can be produced in zero-shrinkage technology by pressure-assisted sintering. The application of axial pressure during sintering supports densification, enhances co-firing of different materials and restrains deformation. However, the sintered surfaces are affected from the release tapes and setters used in the pressure-assisted sintering process. In this study, the effect of release tape particle size on the surface properties of sintered substrates was investigated. Moreover, the substitution of release tape by the use of a vitreous carbon setter was tested. Surface roughness and sheet resistances of metallic thin-films on the respective samples were determined. It was found, that roughness of the substrates is not directly correlated with the adequacy of the surface for thin-film deposition. Compared to a freely sintered sample with an average roughness (Ra) of 0.31 μm, pressure-assisted sintering created smoother surfaces using fine-grained tapes (Ra = 0.18 μm) and rougher surfaces using coarse release tapes (Ra = 0.46 mm). Still, sheet resistances were higher on all sinter-pressed samples. The vitreous carbon setter created unusual, trenched surfaces structures, characterized by varying roughness values and intermediate sheet resistances on the LTCCs tested.
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Kheraif, Abdulaziz Abdullah Al. "Surface Roughness of Polyvinyl Siloxane Impression Materials Following Chemical Disinfection, Autoclave and Microwave Sterilization." Journal of Contemporary Dental Practice 14, no. 3 (2013): 483–87. http://dx.doi.org/10.5005/jp-journals-10024-1349.
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ABSTRACT Background Autoclave sterilization and microwave sterilization has been suggested as the effective methods for the disinfection of elastomeric impressions, but subjecting elastomeric impressions to extreme temperature may have adverse effects on critical properties of the elastomers. Aim To evaluate the effect of chemical disinfection as well as autoclave and microwave sterilization on the surface roughness of elastomeric impression materials. Materials and methods The surface roughness of five commercially available polyvinyl siloxane impression materials (Coltene President, Affinis Perfect impression, Aquasil, 3M ESPE Express and GC Exafast) were evaluated after subjecting them to chemical disinfection, autoclaving and microwave sterilization using a Talysurf Intra 50 instrument. Twenty specimens from each material were fabricated and divided into four equal groups, three experimental and one control (n = 25). The differences in the mean surface roughness between the treatment groups were recorded and statistically analyzed. Results No statistically significant increase in the surface roughness was observed when the specimens were subjected to chemical disinfection and autoclave sterilization, increase in roughness and discoloration was observed in all the materials when specimens were subjected to microwave sterilization. Conclusion Chemical disinfection did not have a significant effect but, since it is less effective, autoclave sterilization can be considered effective and autoclaving did not show any specimen discoloration as in microwave sterilization. Microwave sterilization may be considered when impressions are used to make diagnostic casts. A significant increase in surface roughness may produce rougher casts, resulting in rougher tissue surfaces for denture and cast restorations. Clinical significance Autoclave sterilization of vinyl polysiloxane elastomeric impressions for 5 minutes at 134°C at 20 psi may be considered an effective method over chemical disinfection and microwave sterilization, because chemical disinfection does not eliminate all disease-causing microorganisms and microwave sterilization leads to a rougher impression surface. How to cite this article Al Kheraif AA. Surface Roughness of Polyvinyl Siloxane Impression Materials Following Chemical Disinfection, Autoclave and Microwave Sterilization. J Contemp Dent Pract 2013;14(3):483-487.
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Weng Mei Kok, Heoy Geok How, Hun Guan Chuah, and Yew Heng Teoh. "Investigating Roughness Effect to Geometrically Necessary Dislocation in Micro-Indentation using Finite Element Analysis." Journal of Advanced Research in Applied Mechanics 104, no. 1 (2023): 25–32. http://dx.doi.org/10.37934/aram.104.1.2532.
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Surface roughness is a well-known factor in effecting to the hardness value in low indentation depth. The rougher surface induces a greater hardness value. However, the hardening mechanisms, such as the effect of geometrically necessary dislocations (GNDs), with surface roughness is rarely discussed. Therefore, the current study revealed the relationship between the surface roughness effect and the material dislocation through GNDs by using finite element analysis. 3D Crystal plasticity finite element indentation model was developed with various surface roughness between 24 to 140 nm and a range of indentation depth 3.55 to 12.27 µm to indent on the copper (111) material. The experimental indentation work was performed to validate the finite element model. The surface roughness was discovered to contribute to GND density. The GNDs distribution is highly dependent on the geometry of surface asperities, as the surface get rougher the GNDs distribution tends to be inhomogeneous. The GND density is exponentially proportional to the roughness effect. The GND density increases from 3.58 × 1014 m-2 for surface roughness 24 nm to 1.01 × 1015 m-2 for surface roughness 140 nm at indentation depth 3.55 µm. Therefore, GND density which contributes to hardening effect causes rougher surface to induce greater hardness value.
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Tilger, Meik, Dirk Biermann, Mohamed Abdulgader, and Wolfgang Tillmann. "The Effect of Machined Surface Conditioning on the Coating Interface of High Velocity Oxygen Fuel (HVOF) Sprayed Coating." Journal of Manufacturing and Materials Processing 3, no. 3 (2019): 79. http://dx.doi.org/10.3390/jmmp3030079.
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Roughening the substrate surface is essential for thermal sprayed coatings. In this regard, sandblasting has established itself as an easy to use surface conditioning procedure. The quality of the obtained roughness depends on the conditions of the sandblasting material, adjusted parameters, and the kind of the process execution (manual or mechanical). These preconditions limit the reproducibility of the roughness obtained. Sandblasting causes residual compressive stress and may also lead to the inclusion of sand particles and notches in the roughened surface, which affects the interfacial properties of the coating, as well as the flexural strength of the coated parts. The hardness of the roughened surface plays, thereby, an important role. However, in order to reliably avoid these effects, microfinishing can be used as an alternative to generate a homogenous roughened substrate surface, control the induced residual stresses, and increase the reproducibility. In addition, the roughened surface pattern can be produced during the chip forming process of the to-be-coated parts. The utilization of the appropriate combination of machining processes and parameters should lead to the required surface pattern and thus to an enhanced coating adhesion and flexural strength of the coated part. The induced residual stresses and the quality of the obtained surface roughness have a significant influence on the coating adhesion and the lifespan of the coated parts. This paper aims to analyze, as a first step, the effect of the turning and microfinishing on the surface conditioning of the bearing steel 100Cr6 (AISI 52100). The investigation concludes by comparing the microfinished with the sandblasted surfaces with regard to the interface to and the adhesion of the WC–Co high velocity oxygen fuel (HVOF) sprayed coatings on them. Surface conditioning plays a decisive role by the induced residual stresses and the elimination of adhesion defects.
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Otto, K. A., K.-D. Matz, S. E. Schröder, et al. "Surface roughness of asteroid (162173) Ryugu and comet 67P/Churyumov–Gerasimenko inferred from in situ observations." Monthly Notices of the Royal Astronomical Society 500, no. 3 (2020): 3178–93. http://dx.doi.org/10.1093/mnras/staa3314.
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ABSTRACT Alteration processes on asteroid and comet surfaces, such as thermal fracturing, (micrometeorite) impacts or volatile outgassing, are complex mechanisms that form diverse surface morphologies and roughness on various scales. These mechanisms and their interaction may differ on the surfaces of different bodies. Asteroid Ryugu and comet 67P/Churyumov–Gerasimenko, both, have been visited by landers that imaged the surfaces in high spatial resolution. We investigate the surface morphology and roughness of Ryugu and 67P/Churyumov–Gerasimenko based on high-resolution in situ images of 0.2 and 0.8 mm pixel resolution over an approximately 25 and 80 cm wide scene, respectively. To maintain comparability and reproducibility, we introduce a method to extract surface roughness descriptors (fractal dimension, Hurst exponent, joint roughness coefficient, root-mean-square slope, hemispherical crater density, small-scale roughness parameter, and Hapke mean slope angle) from in situ planetary images illuminated by LEDs. We validate our method and choose adequate parameters for an analysis of the roughness of the surfaces. We also derive the roughness descriptors from 3D shape models of Ryugu and orbiter camera images and show that the higher spatially resolved images result in a higher roughness. We find that 67P/Churyumov–Gerasimenko is up to 6 per cent rougher than Ryugu depending on the descriptor used and attribute this difference to the different intrinsic properties of the materials imaged and the erosive processes altering them. On 67P/Churyumov–Gerasimenko sublimation appears to be the main cause for roughness, while on Ryugu micrometeoroid bombardment as well as thermal fatigue and solar weathering may play a significant role in shaping the surface.
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Zhao, Da Peng, Yuan Zhang, He Min Nie, and Ming Yan. "Mesenchymal Stem Cells Adhesion on Micro-to-Nano-Scaled Hierarchical Ti Implants Fabricated by Powder Metallurgy and Anodization." Key Engineering Materials 770 (May 2018): 70–79. http://dx.doi.org/10.4028/www.scientific.net/kem.770.70.
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The osseointegration of titanium (Ti) implants highly depends on their surface properties, including roughness, wettability and composition. Ti surfaces with micron-scale roughness have demonstrated more rapid bone apposition compared with polished ones. Besides, Ti implants with nanostructured surface also exhibit better cell adhesion and proliferation behavior. However, the optimal surface for bone regeneration is still unknown, partly due to the difficulty in fabricating surfaces with highly reproducible micron-and nanotopography. In this study, Ti implants with two hierarchies of roughness were fabricated by powder metallurgy, followed by anodization treatment to obtain self-assembled TiO2nanotubes on the micro-roughened surface. X-ray diffraction (XRD), scanning electron microscopy (SEM), 3D Laser Scanning Microscope (3D LSM), and fluorescence microscope were used to investigate the properties of the samples.Raof the powder metallurgy surface was about 5 μm, while, nanotubes of around 100 nm in diameter were observed after the anodization process. Compared with the reference samples, i.e., the ones with either smooth or single-level-structure surfaces, the ones with micro-to-nanoscaled hierarchical topography exhibited lower contact angle, higher protein adsorption and significantly improved mesenchymal stem cells (MSCs) early adhesion.
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Podulka, Przemysław, Monika Kulisz, and Katarzyna Antosz. "Evaluation of High-Frequency Measurement Errors from Turned Surface Topography Data Using Machine Learning Methods." Materials 17, no. 7 (2024): 1456. http://dx.doi.org/10.3390/ma17071456.
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Manufacturing processes in industry applications are often controlled by the evaluation of surface topography. Topography, in its overall performance, includes form, waviness, and roughness. Methods of measurement of surface roughness can be roughly divided into tactile and contactless techniques. The latter ones are much faster but sensitive to external disturbances from the environment. One type of external source error, while the measurement of surface topography occurs, is a high-frequency noise. This noise originates from the vibration of the measuring system. In this study, the methods for reducing high-frequency errors from the results of contactless roughness measurements of turned surfaces were supported by machine learning methods. This research delves into optimizing filtration methods for surface topography measurements through the application of machine learning models, focusing on enhancing the accuracy of surface roughness assessments. By examining turned surfaces under specific machining conditions and employing a variety of digital filters, the study identifies the Gaussian regression filter and spline filter as the most effective methods at a 22.5 µm cut-off. Utilizing neural networks, support vector machines, and decision trees, the research demonstrates the superior performance of SVMs, achieving remarkable accuracy and sensitivity in predicting optimal filtration methods.
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Xu, Zhijia, Qinghui Wang, and Jingrong Li. "Modeling porous structures with fractal rough topography based on triply periodic minimal surface for additive manufacturing." Rapid Prototyping Journal 23, no. 2 (2017): 257–72. http://dx.doi.org/10.1108/rpj-09-2015-0121.
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Purpose The purpose of this paper is to develop a general mathematic approach to model the microstructures of porous structures produced by additive manufacturing (AM), which will result in fractal surface topography and higher roughness that have greater influence on the performance of porous structures. Design/methodology/approach The overall shapes of pores were modeled by triply periodic minimal surface (TPMS), and the micro-roughness details attached to the overall pore shapes were represented by Weierstrass–Mandelbrot (W-M) fractal representation, which was integrated with TPMS along its normal vectors. An index roughly reflecting the irregularity of fractal TPMS was proposed, based on which the influence of the fractal parameters on the fractal TPMS was qualitatively analyzed. Two complex samples of real porous structures were given to demonstrate the feasibility of the model. Findings The fractal surface topography should not be neglected at a micro-scale level. In addition, a decrease in the fractal dimension Ds may exponentially make the topography rougher; an increase in the height-scaling parameter G may linearly increase the roughness; and the number of the superposed ridges has no distinct influence on the topography. Furthermore, the synthesis method is general for all implicit surfaces. Practical implications The method provides an alternative way to shift the posteriori design paradigm of porous media to priori design mode through numeric simulation. Therefore, the optimization of AM process parameters, as well as the porous structure, can be potentially realized according to specific functional requirement. Originality/value The synthesis of TPMS and W-M fractal geometry was accomplished efficiently and was general for all implicit freeform surfaces, and the influence of the fractal parameters on the fractal TPMS was analyzed more systematically.
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Cai, Zhi-Jie, Xi-Qing Zheng, Hui-Qing Lan, Liu-Na Wang, Si-Wei Yang, and Rui Shen. "Predictive Model for Scuffing Temperature Field Rise of Spiral Bevel Gears under Different Machining Conditions." Lubricants 12, no. 10 (2024): 354. http://dx.doi.org/10.3390/lubricants12100354.
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Spiral bevel gears are extensively employed in mechanical transmissions; however, they are prone to adhesive wear when operating under high-speed and heavy-load conditions. Research indicates that the tooth surface roughness of gears significantly influences the friction and wear of the meshing gears. The present study delves into the origins of tooth surface roughness through the integration of the W-M function and fractal theory. Utilizing an involute helical gear with surface roughness for tooth cutting, a three-dimensional model is established with roughened tooth surfaces. This paper introduces an approach to developing three-dimensional gear models with roughness and applies the finite element method to perform thermodynamic analysis on gears exhibiting diverse levels of surface roughness. The thermal analysis of gears with varying degrees of roughness was conducted using the finite element method. Comparative analysis of the results under specific operating conditions elucidated the impact of roughness on tooth surface temperature rise. In order to validate the simulation model, an experimental test platform for spiral bevel gears of identical size was established. This model integrates tooth surface roughness with thermodynamic analysis, allowing for the rapid assessment of tooth surface temperature rise under different machining conditions, and reducing the cost of validating predicted tooth surface load-carrying capacity.
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Zhou, Zilong, Jing Zhang, Xin Cai, Shanyong Wang, Xueming Du, and Haizhi Zang. "Permeability Experiment of Fractured Rock with Rough Surfaces under Different Stress Conditions." Geofluids 2020 (June 1, 2020): 1–15. http://dx.doi.org/10.1155/2020/9030484.
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To investigate the permeability changes and the mechanisms of fractured rock under dynamic and static stresses produced by earthquakes, permeability experiments on fractured rock with rough surfaces under axial dynamic and static stresses were conducted on the MTS815 Rock Mechanics Testing System. Surface asperity was investigated by scanning the specimen surfaces before and after testing. The results show that the roughness of fracture surface has a great influence on the permeability when the axial displacement is not enough to cause the fracture rock to slip. Moreover, the rougher fracture surface leads to severer surface damage as indicated by the more gouge productions. The accumulation of gouge materials on larger roughness fracture surfaces causes a slow drop in permeability. The fracture surfaces experience larger degradations, but it has small weights of gouge materials on fracture surface after testing under axial dynamic stress. The reason is that the gouge material transport and mobilization tend to occur in process of dynamic loading. Therefore, the permeability drops of axial dynamic stress are larger than those of axial static stress.
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Rifat, Mustafa, Saurabh Basu, Edward C. De Meter, and Guha Manogharan. "Effect of Prior Surface Textures on the Resulting Roughness and Residual Stress during Bead-Blasting of Electron Beam Melted Ti-6Al-4V." Crystals 12, no. 3 (2022): 374. http://dx.doi.org/10.3390/cryst12030374.
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The finishing of additive manufactured (AM) components is crucial for endowing them with fatigue resistance. Unfortunately, current AM processes naturally promote anisotropic surface characteristics that make it challenging to optimize finishing processes. In this study, bead-blasting is explored as a process for finishing Electron Beam Melted (EBM) Ti-6Al-4V. The effects of anisotropic roughness characteristics on the mechanics of bead-blasting are delineated using surface texture measurements via optical profilometry and residual stress measurements via X-ray diffraction. As-received surfaces resulting from AM, as well as those that have been Electrical Discharge Machined (EDM), are studied. It is seen that pre-processed roughness textures heavily influence the final textures and residual stresses. These linkages are quantified using a plasticity index as the governing metric—a rougher surface features a larger plastic index, which results in comparatively greater evolution of its texture characteristics than a smoother surface after equivalent bead-blasting treatments. The mechanics of this evolution are delineated using energy-controlled indentation as a model representing a single impact in bead-blasting. It is seen that rougher surfaces featuring complex textures in as-received states also produce complex stress states featuring a greater level of locally tensile stresses during indentation compared with smoother surfaces. Approaches to address these complications are proposed that can potentially transform a printed, non-functional surface into one that is optimized for fatigue resistance.
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Kido, Daisuke, Keiji Komatsu, Toshikatsu Suzumura, et al. "Influence of Surface Contaminants and Hydrocarbon Pellicle on the Results of Wettability Measurements of Titanium." International Journal of Molecular Sciences 24, no. 19 (2023): 14688. http://dx.doi.org/10.3390/ijms241914688.
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Hydrophilicity/hydrophobicity—or wettability—is a key surface characterization metric for titanium used in dental and orthopedic implants. However, the effects of hydrophilicity/hydrophobicity on biological capability remain uncertain, and the relationships between surface wettability and other surface parameters, such as topography and chemistry, are poorly understood. The objective of this study was to identify determinants of surface wettability of titanium and establish the reliability and validity of the assessment. Wettability was evaluated as the contact angle of ddH2O. The age of titanium specimens significantly affected the contact angle, with acid-etched, microrough titanium surfaces becoming superhydrophilic immediately after surface processing, hydrophobic after 7 days, and hydrorepellent after 90 days. Similar age-related loss of hydrophilicity was also confirmed on sandblasted supra-micron rough surfaces so, regardless of surface topography, titanium surfaces eventually become hydrophobic or hydrorepellent with time. On age-standardized titanium, surface roughness increased the contact angle and hydrophobicity. UV treatment of titanium regenerated the superhydrophilicity regardless of age or surface roughness, with rougher surfaces becoming more superhydrophilic than machined surfaces after UV treatment. Conditioning titanium surfaces by autoclaving increased the hydrophobicity of already-hydrophobic surfaces, whereas conditioning with 70% alcohol and hydrating with water or saline attenuated pre-existing hydrophobicity. Conversely, when titanium surfaces were superhydrophilic like UV-treated ones, autoclaving and alcohol cleaning turned the surfaces hydrorepellent and hydrophobic, respectively. UV treatment recovered hydrophilicity without exception. In conclusion, surface roughness accentuates existing wettability and can either increase or decrease the contact angle. Titanium must be age-standardized when evaluating surface wettability. Surface conditioning techniques significantly but unpredictably affect existing wettability. These implied that titanium wettability is significantly influenced by the hydrocarbon pellicle and other contaminants inevitably accumulated. UV treatment may be an effective strategy to standardize wettability by making all titanium surfaces superhydrophilic, thereby allowing the characterization of individual surface topography and chemistry parameters in future studies.
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Seo, Beomdeok, Hideyuki Kanematsu, Masashi Nakamoto, Yoshitsugu Miyabayashi, and Toshihiro Tanaka. "Copper Surface Treatment Method with Antibacterial Performance Using “Super-Spread Wetting” Properties." Materials 15, no. 1 (2022): 392. http://dx.doi.org/10.3390/ma15010392.
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In this work, a copper coating is developed on a carbon steel substrate by exploiting the superwetting properties of liquid copper. We characterize the surface morphology, chemical composition, roughness, wettability, ability to release a copper ion from surfaces, and antibacterial efficacy (against Escherichia coli and Staphylococcus aureus). The coating shows a dense microstructure and good adhesion, with thicknesses of approximately 20–40 µm. X-ray diffraction (XRD) analysis reveals that the coated surface structure is composed of Cu, Cu2O, and CuO. The surface roughness and contact angle measurements suggest that the copper coating is rougher and more hydrophobic than the substrate. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) measurements reveal a dissolution of copper ions in chloride-containing environments. The antibacterial test shows that the copper coating achieves a 99.99% reduction of E. coli and S. aureus. This study suggests that the characteristics of the copper-coated surface, including the chemical composition, high surface roughness, good wettability, and ability for copper ion release, may result in surfaces with antibacterial properties.
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Honda, Takashi, Katsuyuki Kida, Edson Costa Santos, and Yuji Kashima. "The Influence of Surface Texture on Rolling-Contact Fatigue of PEEK Bearings in Water." Advanced Materials Research 154-155 (October 2010): 1713–16. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.1713.
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The effect of machining conditions on the rolling contact fatigue (RCF) strength of PEEK polymer bearings was investigated. RCF tests were carried out by using bearings machined by different conditions. The surface profile and roughness were observed before and after testing by laser confocal microscope. Pitting and cracking were associated with the different initial surface conditions. From the obtained results, we found that the RCF strength of machined surfaces decreases when the surface becomes rougher.
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Pereira, Rita, Paulo Maia, Jose Vicente Rios-Santos, et al. "Influence of Titanium Surface Residual Stresses on Osteoblastic Response and Bacteria Colonization." Materials 17, no. 7 (2024): 1626. http://dx.doi.org/10.3390/ma17071626.
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Grit basting is the most common process applied to titanium dental implants to give them a roughness that favors bone colonization. There are numerous studies on the influence of roughness on osseointegration, but the influence of the compressive residual stress associated with this treatment on biological behavior has not been determined. For this purpose, four types of surfaces have been studied using 60 titanium discs: smooth, smooth with residual stress, rough without stress, and rough with residual stress. Roughness was studied by optic interferometry; wettability and surface energy (polar and dispersive components) by contact angle equipment using three solvents; and residual stresses by Bragg–Bentano X-ray diffraction. The adhesion and alkaline phosphatase (ALP) levels on the different surfaces were studied using Saos-2 osteoblastic cultures. The bacterial strains Streptococcus sanguinis and Lactobacillus salivarius were cultured on different surfaces, determining the adhesion. The results showed that residual stresses lead to increased hydrophilicity on the surfaces, as well as an increase in surface energy, especially on the polar component. From the culture results, higher adhesion and higher ALP levels were observed in the discs with residual stresses when compared between smooth and roughened discs. It was also found that roughness was the property that mostly influenced osteoblasts’ response. Bacteria colonize rough surfaces better than smooth surfaces, but no changes are observed due to residual surface tension.
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El-Gabry, Lamyaa A., and Deborah A. Kaminski. "Experimental Investigation of Local Heat Transfer Distribution on Smooth and Roughened Surfaces Under an Array of Angled Impinging Jets." Journal of Turbomachinery 127, no. 3 (2004): 532–44. http://dx.doi.org/10.1115/1.1861918.
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Measurements of the local heat transfer distribution on smooth and roughened surfaces under an array of angled impinging jets are presented. The test rig is designed to simulate impingement with crossflow in one direction. Jet angle is varied between 30, 60, and 90deg as measured from the target surface, which is either smooth or randomly roughened. Liquid crystal video thermography is used to capture surface temperature data at five different jet Reynolds numbers ranging between 15,000 and 35,000. The effect of jet angle, Reynolds number, gap, and surface roughness on heat transfer and pressure loss is determined along with the various interactions among these parameters.
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J. Nowak, Wojciech, Krzysztof Siemek, Kamil Ochał, Barbara Kościelniak, and Bartek Wierzba. "Consequences of Different Mechanical Surface Preparation of Ni-Base Alloys during High Temperature Oxidation." Materials 13, no. 16 (2020): 3529. http://dx.doi.org/10.3390/ma13163529.
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The influence of surface roughness on its high temperature oxidation for an Ni-base superalloy was studied using laser profilometry, atomic force microscopy, mass change measurements, glow-discharge optical emission spectrometry, scanning electron microscopy, X-ray diffraction, and positron annihilation methods. The isothermal and cyclic air oxidation tests were performed at 1000 °C and showed dependence of oxidation behavior on surface roughness. Smoother surfaces oxidation resulted in the formation of a multilayered oxide scale consisting of NiO, Cr2O3, and internally oxidized Al2O3 while a rougher surface formed protective Al2O3 scale. The factors responsible for different oxidation behaviors were determined as higher concentration of vacancies and increased residual stresses in the near-surface region of studied alloys.
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XU, YUTING, XIAOLI CAO, CARL HOUTMAN, BO LI, WENXUAN MO, and XIAOHONG LI. "Effects of metal surface morphology on deposition behavior of microstickies from papermaking white water." TAPPI Journal 22, no. 7 (2023): 466–73. http://dx.doi.org/10.32964/tj22.7.466.
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Deposition of small adhesive particles, called microstickies, onto pulp processing equipment and paper machines causes quality and operational problems for recycling mills. The factors that control deposition of microstickies onto surfaces of metal parts remain unclear. In this work, aluminum surfaces with a range of surface roughness were exposed to slurries containing micros-tickies. The deposition results showed that flat surfaces promote the aggregation and deposition of microstickies particles. Uneven surfaces tended to favor deposition of smaller microstickies, 0.2–1 μm, which may be related to greater contact area presented by the rougher surface. This work provides insights into the deposition of microstickies.
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Goyenvalle, Eric, Eric Aguado, Ronan Cognet, Xavier Bourges, and G. Daculsi. "Calcium Phosphate Ceramic Blasting on Titanium Surface Improve Bone Ingrowth." Key Engineering Materials 361-363 (November 2007): 1351–54. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.1351.
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Surface roughness modulates the osseointegration of orthopaedic and dental titanium implants. High surface roughness is currently obtained by blasting of titanium implants with silica or aluminium abrasive particles. This process includes into the surface abrasive particles and may cause the release of cytotoxic silica or aluminium ions in the peri implant tissue. To overcome this drawback, we currently develop an innovative gridblasting process using Biphasic Calcium Phosphate (BCP) particles (RBBM Resorbable and Biocompatible Blast Media) to generate biocompatible roughened titanium surface. This work present the technique of blasting using RBBM particles to provide a roughened surface which does not release cytotoxic elements and (ii) to assess the effects of such a roughened surface for bone osteointegration in critical size rabbit defect. Our results demonstrate that resorbable biphasic calcium phosphate abrasive particles can be used to create titanium surface roughness. This grid blasting process increases surface roughness of titanium implants and offers a non cytotoxic surface for rapid and efficient osteointegration.
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Nurhidayanti Nurhidayanti, Lukmanul Hakim Arma, Rusdi Nur, and Abdul Salam. "Experimental Investigation of Fused Deposition Modelling 3D Printing Process on Propeller Blade Roughness Using PLA+." Proceeding of the International Conferences on Engineering Sciences 1, no. 2 (2024): 38–55. https://doi.org/10.61132/iconfes.v1i2.21.
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The manufacturing process now emphasizes producing high-quality products. Additive manufacturing, particularly Fused Deposition Modeling (FDM), fulfills these demands by enabling precise fabrication through filament layer extrusion. This study investigates the effects of process parameters, specifically layer thickness and infill density, on the surface roughness of PLA+ polymer material using FDM. Surface orientation plays a crucial role in determining the quality of printed components, such as propeller blades with complex geometries. Surface roughness was analyzed using the Gaussian Filter method with cutoffs of 800 µm and 25 µm at different surface points, namely top and bottom. The results indicate that layer thickness significantly impacts surface roughness. A layer thickness of 0.1 mm yielded smoother surfaces compared to 0.3 mm, as the smaller layer height reduces the formation of uneven surface lines and roughness. The higher layer thickness (0.3 mm) increased the distance between layers, resulting in a rougher texture. In conclusion, optimizing layer thickness, particularly at 0.1 mm, improves surface quality. These findings highlight the importance of parameter control in achieving high-quality 3D printed components, especially for intricate geometries like propeller blades.
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Wang, Le Feng, Bin Guo, Gui Ming Huang, Wei Bin Rong, and Li Ning Sun. "Effects of Asperity Shape on the Adhesion Hysteresis Originated from Surface Roughness." Advanced Materials Research 213 (February 2011): 201–5. http://dx.doi.org/10.4028/www.scientific.net/amr.213.201.
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Adhesion of solid surfaces plays a significant role in many technical fields especially at micro and nano scale. The effect of asperity shape on the adhesion hysteresis originated from surface roughness has been investigated theoretically in this paper. Based on the adhesive contact model of single asperities with axisymmetric power-law shapes, the roughness-induced adhesion hysteresis is modeled by assuming the asperity heights follow a Gaussian distribution on the rough surface. The analysis results show that the dissipation energy decreases dramatically when the surface becomes rougher for all the shape indices, and the shape index affects the adhesion hysteresis at different levels with the variance of surface roughness. A general parameter consisting of the shape index of asperities is proposed to characterize the adhesion hysteresis. These will be helpful to understand and control the adhesion hysteresis for solid-solid contact.