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The effect of the surface roughness of the coating and the composition of the upper layer on the solid particle erosion of multilayer nanostructured coatings applied via cathodic arc evaporation (CAEPVD) method was investigated. CrN/TiN nanostructured multilayer coating (TiN as the upper layer) and TiN/CrN nanostructured multilayer coating (CrN as the upper layer) were applied on 410 stainless steel through the CAEPVD method with the following architecture. 1) a bottom layer of Cr and CrN deposited on the substrate, 2) nanolayers of TiN and CrN deposited on the bottom layer alternately and 3) an upper layer of CrN or TiN deposited on the nanolayers. After applying the coating, half of the samples were polished to obtain smooth surfaces, while the other half remained unpolished, resulting in rough surfaces. Surface morphology, phases identification, adhesion, mechanical, and erosion behavior of the coatings were characterized using SEM, XRD, Rockwell adhesion measurements, nanoindentation test, and solid particle impingement, respectively. The nano-scale indentation results demonstrated that the hardness, Young's modulus, H/E, and H3/E2 of the CrN/TiN coating were 5.57, 1.42, 3.86, and 85.39 times larger than those of the substrate. For the TiN/CrN coating, the values were 4.04, 1.13, 3.53 and 51.68 times greater than those of the substrate. The results of the erosion test showed that the erosion mass loss for the CrN/TiN and TiN/CrN coatings decreased up to 73% and 67%, respectively. Additionally, surface smoothing improved erosion resistance by 40% for both coatings. This shows that the smoothed CrN/TiN nanostructured multilayer coating is an excellent candidate for increasing the erosion resistance due to the higher ratios of H/E and H3/E2 and smoother surface.

In this work, CuO mixed lemon peel dielectric is used along with the 3D printed aluminium electrodes to enhance the electrical discharge machining (EDM) performance. This work mainly focuses on improving the surface quality by optimizing the powder concentration and stirring velocity. A full factorial of 27 experiments is carried out with input parameters such as pulse off time with 3 levels (28, 58 and 98 μs), powder concentration with 3 levels (1, 2 and 3 g/L) and stirring velocity with 3 levels (900, 1800 and 2700 rpm), while keeping the current, pulse on and voltage as constant. For all trials, the output responses viz. surface roughness (SR) and material removal rate (MRR) are noted. It is evidenced that EDM performance is influenced by the stability of powder mixed dielectric. To understand the most influential input parameter and its level, analysis of variance (ANOVA) and grey relational analysis (GRA) are carried out. The output analysis exhibited that powder concentration of 2 g/L, stirring velocity of 1800 rpm and pulse off time of 28 μs as the best combination for the best quality of finish (4.72 μm) with high MRR (0.0035 g/min) than the 1 g/L PC with 900 rpm SV for the best quality finish (5.87 μm) along high MRR (0.0029 g/min) and 3 g/L PC with 2700 rpm SV for the best quality finish (5.38 μm) with high MRR (0.0030 g/min) having pulse off time of 28 μs. The experimental findings are validated with a 3D surface plot and SEM images taken on the machined surface. Also, a simulation model is built to understand the flow velocity profiles. This helps ensure the minimum stirring velocity to be maintained to enhance the stability of powder mixed dielectric.

2D profile lines play a critical role in cost-effectively evaluating rock joint properties and shear strength. However, the interval (ΔIL) between these lines significantly impacts roughness and shear strength assessments. A detailed study of 45 joint samples using four statistical measures across 500 different ΔIL values identified a clear line interval effect with two stages: stable and fluctuation-discrete. Further statistical analysis showed a linear relationship between the error bounds of four parameters, shear strength evaluation, and their corresponding maximum ΔIL values, where the gradient k of this linear relationship was influenced by the basic friction angle and normal stress. Accounting for these factors, lower-limit linear models were employed to determine the optimal ΔIL values that met error tolerances (1%–10%) for all metrics and shear strength. The study also explored the consistent size effect on joints regardless of ΔIL changes, revealing three types of size effects based on morphological heterogeneity. Notably, larger joints required generally higher ΔIL to maintain the predefined error limits, suggesting an increased interval for large joint analyses. Consequently, this research provides a basis for determining the optimal ΔIL, improving accuracy in 2D profile line assessments of joint characteristics.

Multi-cation phosphate coatings are used in various industries today to enhance the properties of the painting process. This study explored the impact of adding nickel and manganese ions to the low-zinc phosphating process on the properties of the resulting coating. The first step of the research examined the influence of the bath phosphating agents’ concentration, temperature and immersion time and pH on the phosphate coating on the steel 41Cr4 substrate. The second step explored the impact of varying concentrations of Zn, Ni and Mn cations in the phosphating bath and the third step compared the characteristics of zinc (single-cation), Zn–Ni (two-cation) and Zn–Ni–Mn (three-cation) phosphate. The surface thickness and weight per unit area of the phosphate coating, the total and free acid values, and the coating morphology and microstructure were measured; corrosion resistance tests including alkali solubility and salt spray tests were conducted. In addition, scratch, impact, hardness and bending tests of the paint layer were performed. The results indicated that introducing Ni2+ and Mn2+ cations into the low-zinc phosphating bath enhances the structure, corrosion resistance and paint adhesion of the phosphate coating. Scanning electron microscope images revealed that the optimal three-cation coating has a cubic and sheeted structure. Atomic force microscope analysis also demonstrated that in the tri-cation phosphate coating, compared to the zinc phosphate coating, the roughness (Ra) decreases by up to 50% and reaches 8.92 nm. The optimal three-cation coating has the highest corrosion resistance, which is attributed to the higher uniformity, lower porosity, fine crystalline structure, and high percentage of corrosion-resistant phases in the coating composition. The time to the onset of initial corrosion signs in the salt spray test, both without and with paint, increases by 50% and 225%, respectively, resulting in 11 and 180 h.

Structural planes play an important role in controlling the stability of rock engineering, and the influence of structural planes should be considered in the design and construction process of rock engineering. In this paper, mechanical properties, constitutive theory, and numerical application of structural plane are studied by a combination method of laboratory tests, theoretical derivation, and program development. The test results reveal the change laws of various mechanical parameters under different roughness and normal stress. At the pre-peak stage, a non-stationary model of shear stiffness is established, and three-dimensional empirical prediction models for initial shear stiffness and residual stage roughness are proposed. The nonlinear constitutive models are established based on elasto-plastic mechanics, and the algorithms of the models are developed based on the return mapping algorithm. According to a large number of statistical analysis results, empirical prediction models are proposed for model parameters expressed by structural plane characteristic parameters. Finally, the discrete element method (DEM) is chosen to embed the constitutive models for practical application. The running programs of the constitutive models have been compiled into the discrete element model library. The comparison results between the proposed model and the Mohr-Coulomb slip model show that the proposed model can better describe nonlinear changes at different stages, and the predicted shear strength, peak strain and shear stiffness are closer to the test results. The research results of the paper are conducive to the accurate evaluation of structural plane in rock engineering.

NiTi alloys exhibit significant potential for biological applications, and the fabrication of customized NiTi geometries is greatly facilitated by the use of laser powder bed fusion (LPBF) processing. However, there are several challenges with post-processing NiTi specimens processed via LPBF, such as uneven, loosely packed, weakly corrosive surfaces, and low dimensional precision. Therefore, solving the surface problem of metals prepared by LPBF has become the key to the application. In this paper, the influence of the solution and parameters on surface roughness, surface shape and size, composition, and corrosion resistance was studied by adjusting the composition of the polishing solution and polishing parameters. The results show that polishing for 2 h in S2 solution (HNO3: HF: H2O = 40:10:50) produces the smoothest surface with the roughness characteristics Sa is 10.41 ± 0.63 μm and Ra is 0.39 ± 0.30 μm. At the same time, the corrosion resistance of polished samples has been significantly improved in simulated body fluids (SBF), and the corrosion current density (Icorr) reduced by up to one order of magnitude, reaching 5.38 ± 0.24 × 10−8. By altering the polishing process duration, it is possible to achieve a micron-level roughness surface while maintaining dimensional accuracy, making LPBF-NiTi more suitable for implant applications. Ultimately, we conclude with a brief discussion of how chemical polishing affects the handling of materials with complex structures. Between 30 and 1 h, LPBF-NiTi scaffolds were polished in S2 solution to provide porosities and dimensional accuracy that best matched the design parameters.

In this work, multivariate analysis was applied to evaluate the influence of the deposition time (t), withdraw speed (v), and heating time (HT) used to produce boehmite conversion coatings and to optimize these conditions aiming the improvement of the final alumina-coated system's anti-corrosive properties. It was verified that v was the most influent factor on the studied variables, showing a positive effect in boehmite conversion coating thickness (BxSthickness) and a negative effect on the global corrosion resistance (Rg) and polarization resistance (Rp) of the whole coating systems. The highest anti-corrosive protection was obtained when conversion coating was produced using t = 284 s; v = 116 mm min−1 and HT = 221 min. The boehmite conversion coating prepared under this condition exhibited a homogeneous morphology, with sharp grains and no defects, high roughness (0.406 μm), and a complex mixture of aluminum and iron oxides in its composition, which may have contributed to the performance observed for the system in the saline medium. This combination also promoted the chemical stability of the whole system in the studied aggressive medium and increased the system's mechanical resistance.

In reinforced concrete structures, the interface between old and new concrete is commonplace in precast splices, repairs, and construction joints, and is vital for structural integrity. While extensive research has been conducted on the mechanical bonding properties of interfaces between new and old concrete, there remains a notable gap in understanding the shear behavior under various interfacial treatments. To investigate the influence of interface preparation methods and surface roughness on the shear performance of new-to-old concrete interface, direct shear tests were conducted on Z-shaped specimens. The surface roughness of the initially cast specimens was measured using 3D laser scanning, and the interface morphology was observed by scanning electron microscopy. A comprehensive analysis of comparison between calculated and experimental shear strength values was conducted on 243 sets of direct shear test data. Results revealed that the surface roughness of the specimens ranged from 0.13–3.69 mm, with voids of 0.5–10 μm width present in the bond interfaces. Two failure modes, namely cohesion and adhesion, were identified in the aggregates on the bond interfaces. Within a specific range, the shear strength of bond interfaces increased with an increase in surface roughness. Additionally, bond interfaces with the same roughness but different surface process methods exhibited varying shear bearing capacities. Furthermore, the formula for calculating the shear strength of bond interfaces based on different surface preparation processes and segmented roughness was developed.

The objective of the present work is to study the effect of liquid nitrogen (LN2) cryogenic on the performance of face milling for producing quality surface in AZ91 magnesium alloy. Machining AZ91 alloy has been a challenging domain due to the risk of ignition or spark during machining, which affects surface finish. In this study, face milling is carried using uncoated carbide inserts in cryogenic condition, and the performance is compared with dry condition based on the surface integrity (SI) characteristics. The findings of this study reveal that use of LN2 results in enhanced surface integrity. Observations showed no harm to alloy microstructure in both conditions, with no alterations to grain integrity in the near machined area. Cryogenic machining resulted in reduction in machining temperature ranging from 146.7 °C to 178.5 °C, when compared to dry condition temperature ranging from 219.4 °C to 251.2 °C. Cryogenic machining considerably generated smoother (Ra = 0.0606 μm) and harder (HV = 116.5) surfaces, and also resulted in compressive residual stresses. This study concludes that cryogenic-assisted milling is an excellent alternative for the production of superior-quality surface in AZ91 alloy.

A novel less-destructive field impression method that overcomes the uncertainties in stability assessments of rock joints in historical monuments, due to material sampling or existing destructive test limitations, has been developed. A thermoplastic resin with low fluidity and a short curing time is used to obtain the surface morphology of rock joints owing to its less destructive nature and wide applicability to the walls and ceilings of historical monuments. However, the insufficient filling of this thermoplastic resin can decrease the geometric accuracy of the impressions. Thus, the geometric accuracy of resin impressions and mortar replicas has been examined through laboratory experiments, and the results have been compared with those obtained using existing silicone-based methods, based on the statistical indicators associated with mechanical replicability. The indicator values of the method developed in this study were comparable to those of the replicas in previous studies that have sufficient geometric accuracy to satisfy mechanical replicability requirements. Furthermore, although roughness-coefficient-based methods underestimate the shear strength because of the insufficient filling of thermoplastic resins, they provide an acceptable safety margin in stability assessments of rock joints. The proposed method is suitable for conducting accurate stability assessments of historical monuments and ensuring their conservation.

The joint roughness coefficient (JRC), introduced in Barton (1973) represented a new method in rock mechanics and rock engineering to deal with problems related to joint roughness and shear strength estimation. It has the advantages of its simple form, easy estimation, and explicit consideration of scale effects, which make it the most widely accepted parameter for roughness quantification since it was proposed. As a result, JRC has attracted the attention of many scholars who have developed JRC-related methods in many areas, such as geological engineering, multidisciplinary geosciences, mining mineral processing, civil engineering, environmental engineering, and water resources. Because of such a developing trend, an overview of JRC is presented here to provide a clear perspective on the concepts, methods, applications, and trends related to its extensions. This review mainly introduces the origin and connotation of JRC, JRC-related roughness measurement, JRC estimation methods, JRC-based roughness characteristics investigation, JRC-based rock joint property description, JRC's influence on rock mass properties, and JRC-based rock engineering applications. Moreover, the representativeness of the joint samples and the determination of the sampling interval for rock joint roughness measurements are discussed. In the future, the existing JRC-related methods will likely be further improved and extended in rock engineering.

Structure plane is one of the important factors affecting the stability and failure mode of rock mass engineering. Rock mass structure characterization is the basic work of rock mechanics research and the important content of numerical simulation. A new 3-dimensional rough discrete fracture network (RDFN3D) model and its modeling method based on the Weierstrass-Mandelbrot (W-M) function were presented in this paper. The RDFN3D model, which improves and unifies the modelling methods for the complex structural planes, has been realized. The influence of fractal dimension, amplitude, and surface precision on the modeling parameters of RDFN3D was discussed. The reasonable W-M parameters suitable for the roughness coefficient of JRC were proposed, and the relationship between the mathematical model and the joint characterization was established. The RDFN3D together with the smooth 3-dimensional discrete fracture network (DFN3D) models were successfully exported to the drawing exchange format, which will provide a wide application in numerous numerical simulation codes including both the continuous and discontinuous methods. The numerical models were discussed using the COMSOL Multiphysics code and the 3-dimensional particle flow code, respectively. The reliability of the RDFN3D model was preliminarily discussed and analyzed. The roughness and spatial connectivity of the fracture networks have a dominant effect on the fluid flow patterns. The research results can provide a new geological model and analysis model for numerical simulation and engineering analysis of jointed rock mass.

الملخص: أهداف البحث: يستخدم سيليكون الوجه والفكين لاستعادة التشوهات الناتجة عن أسباب خلقية أو مكتسبة. ومع ذلك، فإن جودة السيليكون بعيدة كل البعد عن المثالية. تهدف هذه الدراسة إلى تقييم تأثير ألياف السليلوز النانوية (ذات قطر نانومتري والطول 2-5 ميكرومتر) بالإضافة إلى الخصائص الفيزيائية والميكانيكية لسيليكون اللدائن المرنة للوجه والفكين. طريقة البحث: تم استخدام نسبتين من الوزن (0,5% و 1%). تم إنشاء 180عينة وتصنيفها إلى مجموعة ضابطة ومجموعتين تجريبيتين. تم تقسيم كل مجموعة إلى ست مجموعات فرعية. لكل مجموعة فرعية، تم استخدام 10 عينات لكل اختبار (قوة التمزق، قياس صلابة المواد، قوة الشد، نسبة الاستطالة، خشونة السطح، ثبات اللون). تم فحص العينات بواسطة المجهر الالكتروني الماسح والتحليل الطيفي للأشعه تحت الحمراء لتحويل ''فورييه” والانبعاثات الميدانية. النتائج: أظهرت المجموعات 0,5% زيادة معنوية عالية في مقاومة التمزق ونسبة الاستطالة وصلابة المواد وخشونة السطح وارتفاع كبير في اختبار مقاومة الشد مقارنة بمجموعة التحكم. ومع ذلك، لم يختلف ثبات اللون بشكل كبير بين المجموعتين. بينما أظهرت المجموعة التجريبية 1%زيادة معنوية في صلابة المواد،مقاومة التمزق، ثبات اللون، خشونة السطح وانخفاض غير معنوي في مقاومة الشد وقيم الاستطالة المئوية بالمقارنة مع مجموعة التحكم العادية. أظهرت صور المجهر الالكتروني الماسح توزيع جيد لألياف السليلوز النانوية مع زيادة ظهور التكتلات عند التراكيز العالية للألياف النانوية وكما أظهر التحليل الطيفي للأشعه تحت الحمراء الى تفاعل ألياف السليلوز النانوية مع السيلكون من خلال مجموعات الهدروكسيل الوظيفيه السطحية. الاستنتاجات: أدت إضافة 0,5% بالوزن من ألياف السليلوز النانوية إلى سيليكون الوجه والفكين إلى زيادة قوة الشد الميكانيكية للمادة، وقوة التمزق، ونسبة الاستطالة والصلابة طالما بقيت ضمن النطاق المقبول في الاستخدام السريري. زادت خشونة السطح بالتناسب المباشر مع كمية الألياف النانوية المضافة. علاوة على ذلك، فإن إضافة 0,5% بالوزن من ألياف السليلوز النانوية إلى بوليمر السيليكون له تأثير ضئيل على ثبات اللون. Abstract: Objectives: Maxillofacial silicone is used to restore abnormalities due to congenital or acquired causes. However, the quality of silicone is far from ideal. This study was aimed at assessing the influence of the addition of cellulose nanofibers (CNFs; several nanometers in diameter and 2–5 μm long) on the physical and mechanical characteristics of maxillofacial silicone elastomers. Methods: Two CNF weight percentages (0.5% and 1%) were tested, and 180 specimens were divided into one control and two experimental groups. Each group was subdivided into six subgroups. In each subgroup, ten specimens subjected to each of the following tests: tearing strength, Shore-A hardness, tensile strength, elongation percentage, surface roughness, and color stability. The samples were additionally analyzed with Fourier transform infrared spectroscopy (FTIR) and field emission scanning electronic microscopy (FESEM). Results: The 0.5% CNF group, compared with the control group, exhibited highly significantly greater tearing strength, elongation percentage, hardness Shore-A, and surface roughness, and substantially greater tensile strength. However, color stability did not significantly differ between groups.The 1% CNF group showed significantly greater Shore-A hardness, tear strength, color stability, and surface roughness, and insignificantly lower tensile strength and percentage elongating values, than the control group. FESEM imaging revealed good CNF dispersion. The FTIR spectra indicated that CNFs interacted with silicone through surface functional hydroxyl groups. Conclusion: Addition of 0.5 wt. % CNF to silicone elastomers increased the material's mechanical tensile strength, tear strength, elongation percentage, and hardness as long as it stayed within the acceptable range for clinical use. Surface roughness increased in direct proportion to the amount of nanofibers added. Moreover, addition of 0.5 wt. % CNF to silicone polymers had insignificant effects on color stability.

In this study, the characterization and cytocompatibility of polyvinyl alcohol:starch (PVA:ST) based membrane tissue scaffolds developed for tissue transparency requirements in tissue engineering applications were evaluated in the presence of sodium dodecyl sulphate (SDS). In this context, two different amounts of SDS were added to the polymer structure of transparent membrane scaffolds to roughen the surfaces of PVA:ST membranes and to promote cell adhesion. In the light of this aim, three different types of membranes were created: A constant PVA:ST ratio of 9:1 (wt:wt) was used as a control and varying amounts of SDS (2 and 4 wt% of the total polymer amount) were added to the polymer solutions. Membrane tissue scaffolds were formed by freeze-drying method. Scaffold properties such as morphology, transparency, water absorption, chemical structure and cytocompatibility were investigated. In terms of physicochemical properties, it was observed that with the addition of SDS, the membranes had a rougher surface while retaining water retention and transparency. In cytotoxicity studies, the membranes were found to be non-cytotoxic and promoted cell proliferation as assessed by MTT assay. Furthermore, the PVA:ST membrane scaffold with 4% SDS added was able to promote the attachment, migration and proliferation of Mouse Embryonic Fibroblasts (MEFs) more than the control group. Overall, the results indicate that SDS-added PVA:ST scaffold membranes are suitable for human corneal stromal regeneration, wound dressing material and neural tissue engineering applications.

Natural fiber reinforced plastics (NFRP) are increasingly used as a sustainable material alternative to glass or carbon fiber reinforced plastics in lightweight solutions. Visible and/or decorative coated components must meet high surface qualities and defects such as fiber print-through due to different expansion behavior of fiber and matrix are not permitted. Various studies investigate the expansion behavior of NFRP under the influence of temperature and humidity on mechanical properties. In contrast, there are no studies that relate these properties to decoratively coated NFRP and the importance for surface quality. The present study aims to fill this gap using a flax fiber reinforced bio-based epoxy resin (FFRP) manufactured by resin transfer molding process (RTM). The surface roughness and the coefficient of thermal expansion (CTE) were determined as a function of the fiber mass fraction. Further, FFRP and carbon fiber reinforced plastics (CFRP) were decoratively coated and subjected to an alternating climate test. The results showed that reducing the fiber mass fraction of an FFRP to 40 % and using a glass-fiber non-woven on the surface, in combination with 50 % fiber mass fraction, were the most promising methods for reducing roughness in the uncoated state. In addition, the FFRP exhibited an increased CTE longitudinally of 11 ppmK−1 and transversely of 105 ppmK−1 to the fiber direction compared to the CFRP (5 and 79 ppmK−1), along with increased roughness of Ra 0.8 compared to 0.6. The effect of fiber print-through was shown for all variants by the stress in the alternating climate test.

The nucleation boiling onset of liquid ammonia in stainless steel, aluminium, and titanium tube segments of ID 4 mm, 6 mm, and 8 mm without flow conditions has been experimentally studied at saturation pressures of 12.5–19.8 bar. It has been shown that heterogeneous nucleation is the determining mechanism for the considered cases. Maximal achievable liquid superheating at 19 K has been observed in the tests at low saturation pressure (12.5 bar), decreasing to 6 K at 19.8 bar. The heating rate in the range of 0.2–60 K min−1 (average heat fluxes of ≈0–4 kW m−2) does not impact much on boiling onset. Internal diameter (4, 6 and 8 mm), roughness (1 and 10 μm) and wettability (10°–50°) do not drastically change the level of maximum achievable superheating before boiling onset. However, quantitatively, the titanium surface with the poorest wettability (≈50°) among considered samples leads to higher overshooting of ammonia bulk temperature by several K. A stainless steel surface with artificial scratches shows a bit higher superheating than a smooth surface. The specific tests showed that ammonia boiling could start at nearly saturation level in the case of a strongly overheated wall. In particular, for ammonia at saturation pressure above 12.5 bar, the required overheating of the wall of 19 K ensures the boiling of ammonia without superheating in the bulk of the liquid.

The asperity wear of rock joints significantly affects their shear behaviour. This study discusses the wear damage of the asperities on the joint surface, highlighting the roughness degradation characteristics during the shear process. The direct shear experiment of artificial specimens containing rock joints was conducted under different normal stresses based on three-dimensional scanning technology. These experimental results showed the contribution of joint wear to roughness degeneration, such as the height, zone, and volume of asperity degeneration. The wear coefficient of the rock joint was obtained based on the volume wear of asperities in the laboratory experiment. The functional relationship between the friction coefficient and wear coefficient is subsequently determined. To quantitatively analyse the wear damage of a joint surface, a calculation method for determining the wear depth of the rock joint after shearing was proposed based on wear theory. The relationship between the ultimate dilation and wear depth was analysed. A coefficient m, which can describe the damage degree of the joint surface, and a prediction method of joint surface roughness after shearing are established. Good agreement between analytical predictions and measured values demonstrates the capability of the developed model. Lastly, the sensitivity factors on the wear depth are explored.

Aim: to evaluate the microhardness (VHN) and surface roughness (Ra) of human enamel surface treated with resin infiltration followed by in office bleaching and to study the effect of artificial saliva (AS) storage time on the VHN and Ra of resin infiltrated enamel. Materials and methods: Eighty enamel specimens were prepared from extracted human premolar teeth. Specimens were divided into two main groups (I and II) then, they were demineralized to create white spot lesions (WSLs). Group I was divided into A and B sub groups. Group A was treated with in office bleaching material while for group B, resin infiltration (Icon) was applied after 24 h storage in AS followed by bleaching. Group II was divided into (C and D). Group C was treated like group B. Specimens in group D were stored in AS for 14 d after treatment with Icon and before application of bleaching. Atomic force microscopy (AFM) Ra analysis and VHN calculation were done. Independent T Test was used to compare between groups at P

Superhydrophobic surfaces are currently a subject of great interest because of their tremendous applications. This study offers greater insight into the self-cleaning ability and anti-icing behavior of the superhydrophobic mild steel and finds application in aircraft and marine systems. Superhydrophobic surfaces were developed on the mild steel surface by improving the roughness and reducing the energy on the surface. Mild steel was chemically etched with HCL solution for 10 min to improve the roughness. After etching, the surfaces were immersed in stearic acid solution for 3 h by solution immersion method to introduce low surface energy. The resultant surfaces have a combination of nano and micro-roughness. The roughness of the samples was measured with the aid of surface roughness tester. The roughness of the prepared surface is 4.213 μm. The microstructure of the as-prepared surface was characterized by a scanning electron microscope. The surfaces have changed to be pine-cone-like structure. The pinecone-like hierarchical structures can generate numerous grooves in which the air can be trapped which lead to a larger contact angle. The contact angle was measured by using a goniometer setup. The obtained contact angle of the surface is as high as 154° with a lower contact angle hysteresis. The surfaces were tested for self-cleaning and ice-delaying properties. The as-prepared superhydrophobic surfaces can self-clean the surface from dirt/dust while the water droplets roll over the surface. A freezing delay time of 392 s was achieved on the surfaces. The prepared surfaces possess better self-cleaning and ice-delaying properties.

The primary aim of this study is to examine the effects of various combinations of working pressure and oxygen gas flow on the properties of zinc oxide (ZnO) coatings. Well-crystalline ZnO coatings are formed by employing RF magnetron sputtering on silicon wafers and glass while varying the working pressure and oxygen gas flow. The structure of the thin film was analyzed using X-ray diffraction (XRD). According to the XRD data, the film's structure was made of ZnO, and the peak (002) was visible. Over the wavelength range of 300–800 nm, the optical transmittance of ZnO thin film was examined. The observed transmission value was on average 85 %. With the assistance of contact angle measurement equipment, the surface energy and contact angle of the developed coatings were both determined. Measured contact angles ranged from 96.6° to 115.3°, whereas the surface energy ranged from 14.08 to 25.11 mJ/m2. The enhancement of the anti-icing attributes was achieved by the modification of the operating pressure and gas flow during the deposition process of the coatings.

A Si-rich NbSi2 coating was prepared on Nb substrate by hot dip silicon plating process, which mainly consists of Nb5Si3 interfacial layer, NbSi2 intermediate layer and silicon-rich NbSi2 outer layer. The Si-rich NbSi2 coating has flat surface and dense structure, and the surface roughness is only 0.218–0.548 μm. Raising the deposition temperature can also significantly increase the growth rate of the Si-rich NbSi2 coating. The hot-dip silicon plating process has an extremely low reaction activation energy (249.99 kJ mol−1), which indicates that there are a large number of activated molecules during hot dip silicon plating. The silicon atoms in the molten bath deposited on the Nb surface and maintained a high chemical potential gradient continuously. Therefore, the solid diffusion reaction of Nb–Si was continuous, and the Nb5Si3 phase was generated and consumed continuously, and transformed into NbSi2 phase, which led to a higher growth rate of coating (1.7 × 10−13 to 4.3 × 10−13 m2 s).

Background/purpose: Dental implants are inevitably exposed to bacteria in oral cavity. Understanding the colonization of bacteria on implant surface is necessary to prevent bacteria-related inflammation surrounding dental implants. The purpose of this study was to investigate the effect of surface properties on biofilm formation on the implant surface. Materials and methods: One early colonizer, Streptococcus gordonii (S. gordonii), and two late colonizers, Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis), were grown on the titanium and zirconia surfaces with two types of surface roughness for 24 and 72 h. Each bacterial biofilm on specimens was quantified using crystal violet assay and observed by scanning electron microscopy. Results: S. gordonii formed more biofilm on the titanium surface than zirconia at the same roughness and more biofilm on the rough surface than smooth one of the same materials at 24 and 72 h of incubation. F. nucleatum adhered on all the surfaces at 24 h and proliferated actively on the surfaces except smooth zirconia at 72 h. P. gingivalis proliferated vigorously on the surfaces at 72 h while it scarcely adhered at 24 h. There was no consistent correlation between contact angle and biofilm formation of the three bacteria. Conclusion: The three bacteria proliferated most on the rough titanium surface and least on the smooth zirconia surface. In addition, the proliferation was affected by the bacterial species as well as the surface properties.

Most of current permeability evaluation models for shale gas reservoirs ignore the influence of imbibition during fracturing, moreover, several of the considerations are different from real conditions, for example, shale pore shape is circular and water film is with equal thickness, which is convenient for calculation but adverse to evaluation accuracy. In the study, shale pore shapes are closer to ellipse by statistically analyzing the scanning electron microscopy results, the thickness of water film is not equal on elliptical pore surface but related to the curvature. Based on these new insights, a quantitative model for determining the unequal thickness of water film was established, and then a new multi-scale elliptical pore permeability model, considering non-equal-thickness water film, wall roughness, stress sensibility, and retention effect, was established based on the multi-scale flow weighting theory. The prediction results of this permeability model are similar to the test results, and are more accurate than that of the previous models. Finally, factors analysis showed that the effect of roughness on permeability was small, but the negative impact of water film and stress sensitivity on permeability was significant.

CFD of convective heat transfer remains a challenge, especially in channels with irregular rough walls due to the complex fluid dynamics over and between these roughness elements. This study investigates the performance of four commonly utilised RANS CFD models, namely Spalart-Allmaras (SA), Realisable k-ε, SST k-ω, and Reynolds Stress Model (RSM) in estimating the velocity and temperature profile as well as the skin friction coefficient and Nusselt number in smooth and rough channels. The CFD results were compared with DNS and experimental data in the literature. The roughness-resolving approach was used for all models to resolve the realistic geometry of irregular roughness in channel flows. The smooth-channel flow study was conducted at Reτ = 500, 1000, 2000, and 5000 and Pr = 0.71. Over this range, compared to smooth-wall DNS data from literature, the RSM showed consistent and satisfactory performance in estimating the velocity and temperature profiles within 2.54% and 4.21%, respectively; leading to the skin friction coefficient and Nusselt number in the smooth channels being predicted very well within 1.94% and 2.03%, respectively. The rough-channel flow study was performed at Reτ = 240, 360, 540, 720, 1000 and Pr = 1, with computational cells 7.8 times that of the smooth channel to resolve the irregular roughness geometry. Over this range, the Realisable k-ε showed the best performance in estimating the roughness function within 6.85%, while the results of the other models were wider at uncertainty levels of up to 36.9%. Similarly, the Realisable k-ε demonstrated the best performance in estimating the skin friction and Nusselt number in rough channels within 2.76% and 9.50%, respectively, while the performance of the other models was to a wider latitude ranging between 15.62% to 26.34%. In the present study, the Realisable k-ε with enhanced wall treatment showed the best capabilities in capturing the mean flow characteristics of both smooth and rough channels; however, its usage should be approached with caution in flows at higher Reynolds numbers. RANS models are also discussed for forced convection heat transfer at high Reynolds numbers. The results of this study should be useful in CFD studies on the effects of roughness in complex geometries without the need for LES and DNS.

Numerous simplified numerical models have been established to optimize the ball burnishing of steel surfaces. Nevertheless, their conceptualization has not considered the tool–part interaction, leading to an unsatisfactory process parameterization. As a solution, a structured numerical simulation has been defined that reproduces this interaction by several friction coefficient approximations. This study provides the tribological process inputs (friction and initial surface conditions) to this model, adapting it to a pre-textured martensitic precipitation hardening stainless-steel. Results show the versatility of the model to reproduce the surface integrity alterations. Hence, this consistent model configuration can be postulated as an economical and efficient approach to tackle ball burnishing parameterization according to the applicability of the manufactured steel parts.

AZ91 magnesium alloy is one of the most popular materials among all cast magnesium alloys due to its excellent corrosion resistance and good cast-ability. Although AZ91 is categorized as soft materials and easy-to-cut, there are many challenges in the finish machining of AZ91. In this research, a comprehensive as well as novel study on the surface integrity of machined AZ91 magnesium alloy is presented. To this end, AZ91 samples are machined under different cutting conditions and afterward, both surface and subsurface features are analyzed. Assessing the finished surface is conducted by surface 3D topography, roughness measurement, and scanning electron microscope. In terms of subsurface characterization, the effect of machining conditions cutting speed and feed rate on the micro hardness variation, subsurface microstructure changes, plastic deformations, and subsurface defects are studied. Results indicated that when machining AZ91, surface defects mostly are formed around the secondary phases. Moreover, twining and shear bands are the main microstructural changes close to the machined surface. Additionally, finishing machining of AZ91 induced subsurface plastic deformation to the depth of 180 μm as well as micro cracks propagation, in secondary phases, to nearly 100 μm under the machined surface.

Wetting film thinning measurement was introduced to clarify the wettability and floatability of solid surfaces with varying roughness. The wettability was quantified using the contact angle measurement combined with the dynamic force microbalance test between solid surfaces and water droplets, while the floatability was investigated by the bubble-solid surface dynamic attachment observation and the induction time measurement. The results show that the water contact angles reduce (14.53°, 12.74°, and 6.71°) with the increase of glass surface roughness, while the water droplet-glass adhesion forces intensify (11.1, 19.1 and 19.2 μN) owing to the stable wetting film. The distortion of the contact surface and the Wenzel state are the causes. In contrast, the hydrophobized surfaces have the growing apparent contact angles (38.08°, 69.81°, and 81.01°), declining adhesion strength and shortening induction time (863, 352 and 12 ms) along with the increasing surface roughness. The weak wettability and fine floatability on the rough hydrophobized surface is reflected in the fast wetting film drainage dynamics and three-phase contact formation, which may be attributed to the wetting film with short diameter on tiny rough nubs and the entrapped air in the grooves as a bridge between the bulk bubble and the solid surface.

Understanding the dynamic characteristics of the droplets on the gas diffusion layer (GDL) of the proton exchange membrane fuel cell (PEMFC) is important to improve fuel cell performance. This paper studies the dynamic characteristics of water droplet detachment from a simplified rough GDL surface by volume of fluid (VOF) method. The rough GDL surface was restructured by designing grooves with cubic pillars on the GDL surface. Results indicate that the gas velocity, space distance, and wettability of the cubic pillars remarkably affect the water droplet detachment. On a high hydrophilic, water droplet exhibits a shorter detachment time regardless of spatial distance and gas velocity. Whereas on a moderate hydrophilic GDL, a large space distance benefits the droplet detachment. However, in both situations referred to above, droplets tend to deviate and adhere to the corner between the channel wall and the GDL surface. On a high hydrophobic GDL, a large space distance and a high gas velocity favor droplet detachment, moreover, droplet shows Cassie mode and can be easily drained out. These findings can guide the optimal design of GDL for water management of high-performance fuel cells.

Zn-soybean nanocrystal composite coating was produced through electrodeposition. The coatings were obtained in the absence and presence of different concentrations of soybean nanocrystals obtained through the bleaching process with a sodium hypochlorite (NaClO) solution and hydrolysis in a sulfuric acid solution. The effect of nanocrystal addition on the coating characteristics was analyzed through scanning electron microscopy (SEM), roughness measurements, hardness measurements, corrosion resistance evaluation and current efficiency determination. Corrosion resistance was evaluated at 0.5 wt% NaCl solution through mass loss and electrochemical measurements. The results obtained indicate that the presence of soybean nanocrystal reduces the hardness, but increases the corrosion resistance of the Zn coating and this effect is related to the decrease in the roughness of the coating.

Leading edge erosion of wind turbine blades causes roughening of the blade’s surface, leading to a reduction of energy production. This paper presents a computational model for the prediction of the roughness evolution of the blade’s surface, based on fatigue damage calculations and rain droplet impact simulations. A novel method for the calculation of material roughness due to multiple random liquid impacts was developed, by considering damage concentration in areas where sharpness due to material removal is formed. Material removal was governed by fatigue damage values. The computational model was compared to roughness measurements from a sample tested in a rain erosion tester. The outputs of this model are 3D surfaces resembling the roughness of the protective coating layer as well as the evolution of surface roughness parameters and mass loss throughout time.

In the present study, understoichiometric TiZrCN, TiZrNbCN, and TiZrSiCN coatings were produced using the cathodic arc technique with a C/N ratio of approximately 0.5 to investigate their potential use in nuclear technology. The coatings were evaluated for their corrosion resistance in 3.5 % NaCl and neutron activation. The effect of adding Si and Nb to the quaternary TiZrCN system was also investigated. The results showed that the addition of Si (∼4.64 at.%) to the matrix of TiZrCN improved their electrochemical properties in NaCl solution, the protective efficiency was 92%, while the Nb addition (∼5.5 at%) lead to the decrease in corrosion resistance by 1.39 times comparing with TiZrCN. Furthermore, after fast neutron irradiation at a nominal power of 1450 kW, none of the coatings were activated, indicating good radiation resistance. It was determined from the structural analysis that the Ti6Al4V substrate before corrosion consists of hexagonal and cubic space groups with different lattice parameters. By adding Si and Nb, a small amount of ZrO2 and Si3N4 was detected along with the main phases in the TiZrCN structure.

Medical grade Ti–6Al–4V implants fabricated using selective laser melting (SLM) are recognized as a commercial biomaterial used for bone repairs and fracture fixation. However, there have been cases of failed bone remodeling and implant infections caused by deficient osteointegration. To improve osteogenesis, the Ti implants are treated by acid-etching. This study focused on the effect of surface treatment by using different percentages of sulfuric acid (H2SO4), hydrochloric acid (HCL), and hydrofluoric acid (HF) on the SLM Ti–6Al–4V. The microstructure and surface topography before and after treatment were evaluated. Then, the presence of a thicker anatase layer that was detectable on the surface was also observed by X-ray diffraction (XRD). The apatite-forming capabilities which indicated a sample bioactivity were assessed in simulated body fluid (SBF) for periods of 3 days and 7 days. The apatite formed on the surface of sample and XRD scanning revealed the deposition of Ca/P, suggesting successful bone-like apatite. The study discovered that these surface improvements were appropriate for the SLM Ti–6Al–4V prior to clinical applications and were likely to yield higher levels of osseointegration.

Surface interaction is an important topic in engineering, and it is generally recognized that the roughness of a surface has a significant impact on numerous physical phenomena, including contact, wear, friction, and heat transmission. AbaqusTMis a robust finite element program commonly used in industry and academics to simulate these phenomena. Nonetheless, generating rough surface models with Abaqus/CAE is quite challenging and may necessitate the usage of auxiliary tools. We present a plug-in called RufGen for automatic finite element model generation of rough surfaces in an Abaqus/CAE environment. RufGen supports all accessible Abaqus elements, from 2D-wire to 3D-solid. The rough surface can be constructed by importing the measured surface profile data as a text file or by entering geometrical parameters through a graphical user interface. An illustrative example is provided for describing the use of RufGen, an open source project available on GitHub.

Some of the key issues with AWJ technology are high roughness, low depth of smooth zone, and grit embedment. When compared to the unsubmerged AWJ, the submerged AWJ gives less divergence and produces higher energy at the cross section of the jet. Hence, this study examined the effects of pressure, traverse rate, and standoff distance on roughness, depth of smooth zone, and grit embedment in both AWJ conditions. Here, single factor experiments are conducted for experimental investigation wherein one factor is varied and the others are kept constant. In comparison, the submerged AWJ gave significant improvement in the roughness and depth of the smooth zone at lower levels of pressure (150 and 200 MPa), higher levels of traverse rate (300 and 350 mm/min) and standoff distance (4, 5 and 6 mm). The significant difference in grit embedment was observed at lower levels of traverse rate (150 and 200 mm/min), higher levels of pressure (300 and 350 MPa), and all the levels of standoff distance (2, 3, 4, 5, and 6 mm). The grit embedment in the submerged condition was lower due to the removal of initially embedded grits due to flushing action produced by cavitation initiation.

Bubble-particle attachment is a key factor in various material processing such as wastewater treatment and flotation separation. Nanobubble's formation and its stability on hydrophobic surfaces with and without surfactants have been scientifically proven and extensively studied in various investigations. However, the influence of particle roughness on the hydrophilic particle-air bubble attachment, which could be completely different from hydrophobic particle-bubble attachment in the presence of nanobubbles, has not been addressed. For tackling this gap, the present work investigated the impact of nanobubbles on the roughed surfaces of glass bead particles. The temperature rise technique as a known method was used for micro/nanobubble size generation. The glass beads were modified by the commonly applied abrasion method to create different roughness magnitudes. The particle-bubble assessment results indicated that the particle roughness could potentially affect the bubble attachment of hydrophilic glass beads while the attachment area of smooth particles was almost zero. Outcomes also were revealed that the modified attachment rate constant increased from 0.1180 to 2.2802 s−1 with the increase of particle surface roughness, indicating a shortening of attachment performance by enhancing the particle surface roughness. However, it was observed that the temperature rise method could improve the particle-bubble attachment only to a marginal extent.

Purpose: To simulate biodegradation and wear of stained and glazed CAD lithium disilicate ceramic, and evaluate their effects on the microbial adherence and mechanical and surface properties of lithium disilicate ceramic Materials and methods: 160 lithium disilicate ceramic discs were fabricated and divided in eight groups according to manual stain and glaze application with a fine paint brush (without stain and glaze; with stain and glaze) and aging procedures (no aging; wear at 30 N load, 1.7 Hz, 3 × 105 cycles; biodegradation by exposure to microcosm biofilm; biodegradation + wear; biodegradation + wear). Profilometry was performed to determine the surface roughness and the wear consequences. Biaxial flexural strength test was performed, and a Streptococcus mutans adherence test was conducted to evaluate the number of colony forming units. Results: Unaged samples with and without stain and glaze presented the lowest values of surface roughness (p

Ceramics-based composites are a special class of materials carrying combined properties that belongs to alloys and metals according to market demands. This makes composites completely different and paves the way for new applications that requires the utmost properties. Machining of such composites is of great importance to finalize the fabrication process with improved part quality; however, the process implies several challenges due to the complexity of the cutting processes and random material structure. The current study aims to examine the machinability characteristics when milling novel material, Cu–B–CrC composites using Al/TiN coated carbide tools. Further, the influence of machining parameters along with the different weight ratios of the powders amounts used to fabricate the machined reinforced samples on output parameters namely surface roughness, tool wear, chip morphology and cutting temperatures was investigated. One of the key findings of the study is the dominant effect of reinforcement ratio (Cu, B, CrC) on machinability, which showed that 5% additive (2% B, 3% CrC) provides improved properties such as surface roughness, tool wear and cutting temperature. Cutting speed alterations play an important role in the machinability characteristics, i.e., increasing value increases flank wear and cutting temperatures and reduces surface roughness. Increasing feed rate increases the surface roughness meanwhile its effect shows changing behavior on the flank wear and cutting temperatures according to cutting speed and reinforcement ratio.

Here, the influence of grinding media with different shapes on the flotation performance of spodumene and its potential mechanism from microscale insights was investigated using a single mineral flotation experiment, X-ray diffraction (XRD) test, scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). The flotation data indicated that under anionic/cationic (sodium oleate (NaOL)/DDA) collectors system, the rod milled spodumene has a higher floatability than ball milled ones. XRD results confirmed that rod medium makes spodumene exposed more {110} and {100} planes, while ball medium makes spodumene exposed more {010} planes. The typical anisotropic surface of spodumene makes the surface of rod milled spodumene possess more Al sites, further confirmed by SEM-EDS and XPS results. Additionally, it was found that the rod milled spodumene presents a larger value of elongation and flatness, which are parameters closely related to bubble adhesion. AFM analysis indicated that rod milled products have a rougher surface, while ball milled products have a smoother surface. Consequently, the rod medium enhanced the adsorption of NaOL/DDA on the spodumene surfaces. This work provides theoretical guidance for optimizing the separation of spodumene from the perspective of grinding.

Objectives: To evaluate the efficacy of activated charcoal powder on extrinsic stain removal and its effect on surface roughness in stained resin composite in comparison with whitening toothpaste. Materials and methods: Sixty-six disk-shaped composite specimens were fabricated using a custom-made ring mold. The specimens were stained using a coffee solution and stored in distilled water at 37 °C. The specimens were divided randomly into two groups, Group 1: Thirty-Three disks were subjected to brushing using whitening toothpaste (Control), and Group 2: Thirty-Three disks were subjected to brushing using charcoal powder. Specimens were evaluated for surface color and surface roughness at baseline after staining protocol and after the brushing process. Results: Changes in color and surface roughness were highly significant (p

Objective: Critically analyzed the existing literature to answer the question ''What is the influence of roughness of surfaces for dental implants obtained by additive manufacturing compared to machined on osteoblastic cell adhesion and proliferation?'' Design: This systematic review followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in the Open Science Framework. The personalized search strategy was applied to Embase, Pub Med, Scopus, and Science Direct databases and Google Scholar and ProQuest grey literature. The selection process was carried out in two stages independently by two reviewers according to the eligibility criteria. The risk of bias was analyzed using a checklist of important parameters to be considered. Results: When applying the search strategy on databases 223 articles were found, after removing the duplicates, 171 were analyzed by title and abstract of which 25 were selected for full reading, of these, 6 met the eligibility criteria. 2 studies were included from the reference list totaling 8 articles included in this systematic review and none were included from the Grey Literature. 7 had a low risk of bias and 1 moderate. Conclusions: 1) Roughness is a property that must be analyzed and correlated with the chemical composition, intrinsic to the alloy and resulting from the surface treatment; morphology of topographic peaks and valleys; printing technique and its parameters; 2) Need for more studies on the biomolecular level to elucidate the mechanism by which the roughness and the morphology of topographical peaks and valleys descriptive of roughness influence osteoblastic adhesion and proliferation.

Marmara White (MW), Bursa Beige (BB), Emprador (EM), and Kütahya Black (KB) natural stones are widely used as kitchen countertops and wet floor covering materials in our country. This study investigated the changes in these natural stones' gloss, roughness, and total color change properties due to the spillage of eight different food, beverage, and cleaning materials. Staining-cleaning cycles were applied to natural stones for 1, 3, and 7 days. In addition, with the help of field emission scanning electron microscopy (FESEM) analysis, the damage caused by these stain effects on the internal structures of these natural stones was investigated. According to the results obtained from the study, after three staining-cleaning cycles, the highest gloss loss was observed in the KB sample at the rate of 97.15 % after the descaler effect, while the minor gloss loss was obtained in the MW sample at the rate of 82.16 %. Furthermore, the highest roughness increase was observed in the KB sample at the rate of 555.1 % after the effect of descaler, while the slightest increase in roughness was obtained in the MW sample at the rate of 395 %. In addition, cooking oil has the most negative effect on natural stones' total color change (ΔE) properties. After three staining-cleaning cycles of the cooking oil effect, ΔE = 20.86 was obtained in the MW sample, while this value was 3.25 in the KB sample.

In this study, monoclinic gallium oxide (β-Ga2O3) epilayer was successfully grown on c-plane, (0001), sapphire substrate by metalorganic chemical vapor deposition (MOCVD) with interplaying growth temperature, TEGa flow rate, and growth time. X-ray diffraction 2θ scans show only three narrow diffraction peaks referred to β-Ga2O3(2¯ 01), (4¯ 02), and (6¯ 03) in all epilayers, indicating a superior crystalline quality. Current-voltage (I–V) measurement reveals that these β-Ga2O3 films are insulating and exhibit high resistance in a range of 1012–1014 Ω. The crystallization characteristics of the epilayers can be effectively improved with thickness through increasing TEGa flow rate and growth time, which was evidenced by X-ray rocking curves and I–V measurements. However, the surface roughness of β-Ga2O3 film increases with growth time and TEGa flow rate. When the growth temperature increases above 825 °C, the thickness of β-Ga2O3 film decreases clearly. Furthermore, it can be found that the growth rate decreased as the growth time increasing. The growth mechanism based on first-principles calculation was proposed as that 3D growth induced by the lattice mismatch between β-Ga2O3 and sapphire starts at nucleation stage, and follows up a lateral growth promoting a 2D growth after the thick epilayer being grown. In addition, the complex chemical reaction between TEGa and oxygen precursors was unraveled by density function theory calculation.

The grinding and polishing of curved stone involve many steps, limiting the process's efficiency. This study proposes a one-step grinding and polishing process to simplify the process and achieve efficient machining. It is achieved by developing the grinding and polishing tools and realizing the entire process on the robotic processing platform, and the tool design is based on the surface roughness of the machined workpiece. The grinding tool is made by selecting the appropriate glue to achieve the connection from carving to polishing. Similarly, the polishing tool is made by selecting the appropriate gel compound system to achieve a high glossiness curved stone surface. The results show that the grinding tool made of epoxy resin YT-CC301 can reduce the curved stone's roughness from 16.281 µm to below 400 nm, and the connection from carving to polishing can be realized by one step. The polishing tool made of sodium alginate and carboxylated chitosan gel compound system or sodium alginate and sodium carboxymethyl cellulose gel compound system can polish the surface of the ground curved stone to the roughness of less than 15 nm, and the surface glossiness can reach more than 120. Therefore, a single step of grinding and polishing of curved stone is achieved.

Hypothesis: The large-scale implementation of hydrogen economy requires immense storage spaces to facilitate the periodic storage/production cycles. Extensive modelling of hydrogen transport in porous media is required to comprehend the hydrogen-induced complexities prior to storage to avoid energy loss. Wettability of hydrogen-brine-rock systems influence flow properties (e.g. capillary pressure and relative permeability curves) and the residual saturations, which are all essential for subsurface hydrogen systems. Model: This study aims to understand which parameters critically control the contact angle for hydrogen-brine-rock systems using the surface force analysis following the DLVO theory and sensitivity analysis. Furthermore, the effect of roughness is studied using the Cassie-Baxter model. Findings: Our results reveal no considerable difference between H2 and other gases such as N2. Besides, the inclusion of roughness highly affects the observed apparent contact angles, and even lead to water-repelling features. It was observed that contact angle does not vary significantly with variations of surface charge and density at high salinity, which is representative for reservoir conditions. Based on the analysis, it is speculated that the influence of roughness on contact angle becomes significant at low water saturation (i.e. high capillary pressure).

The morphology-dependent antibacterial activity of zinc oxide (ZnO) nanoparticles with three different morphologies, nanowall (NW), nanosphere (NS), and, nanorod (NR) was rigorously investigated to elucidate the influence of shape and size on their performance. Their morphological, surface, and structural characteristics were meticulously analyzed using SEM, BET, and XRD techniques. The antibacterial activity of synthesized ZnO samples was initially investigated and validated through in silico docking studies against nine bacterial strains, specifically targeting 1GCI, 2DCJ, 6KMM and 3T07, 6KVQ, 1MWT from gram-positive Bacillus sp. and Staphylococcus sp. respectively, 6N38, 6CRT, 6GRH from gram-negative E. coli. The docking simulations were performed using Autodock 4.2 software, yielding promising results characterized by negative binding energies, indicative of favorable interactions. The invitro studies were assessed against three same bacteria mentioned above using the disk diffusion method. The results demonstrated a pronounced dependency of antibacterial activity on the surface area, average crystallite size, and surface roughness of ZnO samples. ZnO (NW) exhibited markedly superior antibacterial properties. This enhanced efficacy is attributed to their higher surface area to volume ratio, smaller average crystallite size and increased surface roughness facilitating more efficient interactions with bacterial cell membranes. ZnO (NR) nanoparticles exhibited enhanced antibacterial activity despite minimal surface area., Competing Interests: Declaration of competing interest The authors declare that they have no financial and personal relationships with other people or organizations that could inappropriately influence or bias their work., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The objective was to evaluate the effect of material (four monolithic zirconia) and surface condition [glazed (G) versus polished after simulation of occlusal adjustment (GAP)] on roughness and volumetric wear (VW) of dental zirconia after chewing simulation (CS). Zirconia specimens (ZS) were fabricated with an approximate diameter of 12.0 mm and a thickness of 1.0 mm. The four types of monolithic zirconia utilized were Prettau 4 Anterior (PA), Lava Plus (LP), Cercon hT (hT), and Cercon xT (xT). All specimens were coated with a thin and uniform layer of Prettau Plus glaze. Additionally, half of the ZS underwent a simulation of occlusal adjustment followed by clinical polishing. The sliding wear test was performed using a chewing simulator set at 30 N, 2 Hz, and 500,000 cycles, employing steatite specimens (SS) to simulate opposing dentition. ZS and SS underwent topographic analysis through optical profilometry to assess volumetric wear (VW) and surface roughness. The average roughness values (μm) of the zirconia ranged from 0.38 h (PA-G before CS) to 2.55 a (PA-GAP after CS), while for the antagonist the values ranged from 1.3 b (LP-G before CS) to 2.6 a (PA-GAP after CS). The VW values (mm 3 ) of the ZS ranged from 0.7 b (LP-G) to 2.5 a (LP-GAP), while for the antagonist the values ranged from 0.17 a (xT-GAP) to 0.33 a (LP-G). The CS increased the roughness of all materials tested, regardless of the surface condition. The glazed condition showed lower roughness than the glazed/occlusal adjustment/polishing condition before the CS for three zirconia (PA, LP and xT) and after the CS for all materials. The surface condition did not significantly influence volumetric wear (VW) for three materials (PA, hT, and xT); however, for the Lava Plus (LP) group, the glazed condition resulted in reduced VW. The VW of the SS was unaffected by the material type or surface condition. In summary, zirconia specimens that underwent occlusal adjustment followed by repolishing demonstrated increased surface roughness compared to the glazed ones, while their wear behavior varied depending on the type of zirconia used., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Objectives: To assess the impact of various organic and inorganic acids on the roughness, demineralization, and collagen secondary structures of human dentin and to compare these effects with those of traditional agents, specifically phosphoric acid (PA) and ethylenediaminetetraacetic acid (EDTA)., Methods: Coronal dentin discs (n = 10) were examined by optical profilometry (roughness) and ATR-FTIR before and after conditioning with 32 % PA, 3 % nitric acid (NA), 20 % citric acid (CA), 20 % phytic acid (IP6) or 17 % EDTA. Spectra data were processed to quantify dentin demineralization (DM%) and percentage area of amide I curve-fitted components of β-turns, 3 10 -helix, α-helix, random coils, β-sheets, and collagen maturation index. Statistical analysis was performed by one-way ANOVA or Kruskal-Wallis for DM% and roughness parameters, and paired t-test/Wilcoxon test for amide I components at significance level set at α = 0.05., Results: All treatments resulted in increased roughness parameters, with the most significant changes occurring primarily with PA, while EDTA exhibited the least changes. DM% was NA>PA>IP6>CA>EDTA in a descending order. Regarding amide I components, NA demonstrated a significant reduction in β-turns, 3 10 -helices, and α-helices and it increased β-sheets and random coils. PA resulted in reduction in β-turns and α-helices while it increased β-sheets. CA and EDTA did not cause significant changes. The collagen maturation index significantly increased only after IP6 treatment., Conclusions: The effect on dentin roughness parameters, demineralization, and collagen secondary structures varied based on the type of dentin surface treatment., Clinical Significance: Understanding the impact of acids on the intrinsic properties of dentin is clinically essential for gaining insights into how these effects influence adhesion to dentin, the long-term stability of resin-based restorations, and the success of remineralization therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Purpose: To evaluate the effect of phytic acid (IP6) on the surface roughness and microhardness of human root canal dentin and compare it to other smear layer removal agents. Materials and methods: Fifty extracted human maxillary incisors were sectioned longitudinally into a total of 100 specimens followed by embedding in auto-polymerizing acrylic resin. The specimens were polished and then randomly divided into five groups (n = 20) according to the test solution used to condition root canal dentin: 17% ethylenediaminetetraacetic acid (EDTA); 10% citric acid (CA); 1% IP6; 37% phosphoric acid (PA); or distilled water (control group). Each specimen was treated with a total volume of 1 ml of each solution for 1 min with agitation. Each group was then divided into two subgroups of 10 specimens each. The specimens of the first subgroup were used to determine microhardness, using Vickers hardness tester, and the specimens of the second subgroup were used to measure surface roughness, using a confocal laser scanning microscope. The results were analyzed statistically using one-way ANOVA and Tukey tests, α = 0.05. Results: All the tested groups exhibited microhardness and surface roughness values that were statistically significantly different when compared with the control group (P 0.05). Conclusions: IP6 and PA showed the lowest microhardness and the highest surface roughness values.

We demonstrate a stationary shoulder friction stir processing (SSFSP) to produce smooth surface finish due to non-rotating action of the shoulder. The present work aims to investigate surface topography of high strength AA7075 aluminum alloy processed by SSFSP at different rotational speeds. The unique approach of 3D surface mapping under high-end digital microscopy carried out to evaluate qualitative as well as quantitative surface behavior of the processed region. The surface topography indicated the little amount of flash generation on the processed zone, while 3D mapping of the surface quantified the surface roughness in longitudinal (PD) as well as transverse direction (ND) of the processing zone. Surface analysis confirmed that amount of flash generation was relied on tool rotational speed. The overall surface roughness characterized by average and peak values in both the directions, demonstrating better surface finish in ND at the higher tool rotation, while better uniformity in PD.