Changes In Roughness Research Articles

Unveiling enhanced sound absorption in coconut wood through hemicellulose and lignin modification

Coconut wood (Cocos nucifera L.) is lightweight and has variable quality, making it a potential candidate for manufacturing sound absorption boards. However, its sound absorption coefficient needs enhancement to optimize its effectiveness in this application. This study aims to enhance its sound absorption properties using eco-friendly hydrogen peroxide and acetic acid treatments. This treatment modified the carbohydrate polymers (hemicellulose and cellulose) and lignin structures in the wood cell wall. The novelty of this approach lies in using these chemicals to improve acoustic performance significantly. Coconut wood samples were treated with a 1:1 acetic acid and hydrogen peroxide mixture for 20, 40, 60, and 80 min. Characterization techniques such as FTIR, XPS, and XRD, and 3D optical profilometry analyzed changes in chemical functionalities, crystallinity, and surface roughness. Sound absorption coefficients were measured using the impedance tube method. Results showed a significant improvement in sound absorption for all treated samples, especially at 60 min. The treatment also enhanced surface roughness, air permeability, porosity, and pore sizes, contributing to better sound absorption. This proposed treatment method addresses environmental consciousness and enhances the sustainable use and utilization of coconut wood.

The effect of re-pressing and glazing on the optical properties of high-density micronized heat-pressed glass ceramic

Recycling high-density micronized (HDM) heat-press glass ceramic ingots to press several restorations would be economical and reduce waste. However, to achieve this, the effects of re-pressing on the optical properties and long-term durability of HDM glass ceramics must be completely understood. The aim of this study was to assess the effects of re-pressing and glazing on the optical properties of HDM heat-press glass ceramic. Twenty-one HDM glass ceramic (Initial LiSi Press) discs were prepared and randomly divided into three groups (n = 7 per group): single heat pressing, double heat pressing, and triple heat pressing. Optical properties, surface roughness, and crystalline structure were measured for each group at three time points: before glazing and thermocycling, after glazing, and after thermocycling. The effect of these independent variables on optical properties were assessed by two-way ANOVA, and Tukey's post hoc test assessed the differences between groups. Heat re-pressing HDM glass ceramic significantly altered its color, reduced translucency, and reduced surface roughness (P < 0.001). After the second heat-press, the color (ΔΕ00) and translucency parameter changes (ΔTP00) exceeded perceptible thresholds but not clinically acceptable thresholds, but these were exceeded after the third press for ΔΕ00. Additionally, glazing lightened the shade of the ceramic, reduced translucency, and reduced surface roughness (P < 0.001), with ΔΕ00 and ΔTP00 changes exceeding the perceptible but not the clinically acceptable threshold. Thermocycling produced ΔTP00 changes that exceeded the clinically acceptable threshold. Further studies of the effects of heat re-pressing on HDM glass ceramic are now needed to progress toward clinical translation.

Effect of Different Modification Techniques on Mechanical and Physical Properties of E-Max CAD Substrate

The world's best-selling glass-ceramic is IPS E.Max CAD. It is known for its versatile applications and is appropriate for the effective manufacturing of comprehensive dental restorations. This experimental study aimed to evaluate the morphological changes, surface roughness, and micro-hardness after modification techniques with KHF2 and NH4HF2 acid etching on e-max cad substrate. Materials and Methods: Forty disc shape of E.Max CAD specimens (thickness 3mm and diameter 10mm) were fabricated and divided into four groups according modification techniques (control group, sandblasting by 70µm of Al2O3, etching with 70 mg of KHF2 and etching with 70mg of NH4HF2),10 samples for each group. Surface roughness, micro-hardness, and microstructure changes of e-max CAD substrate have been measured. Results: The higher mean value for the surface roughness (Ra) was in the group (ECNH4HF2), followed by (ECKHF2) whereas the lowest mean value of surface roughness was in the group (ECC) followed by (ECSB). While for the micro-hardness test, the (ECKHF2) group demonstrated the highest mean value in comparison with other treated groups. Finally, SEM results for both untreated and sandblasted groups revealed there is a smooth and no deep morphological change for their surfaces. While the SEM analysis revealed that the e-max cad surfaces after KHF2 and NH4HF2 showed rough morphology with fine grains result and random porosities. Conclusions: Etching with KHF2 and NH4HF2 yielded higher microstructure changes and roughness than other techniques. While KHF2 etchant was more effective on E.Max CAD surface micro-hardness in comparison with other treated groups.

Effect of Grinding and Polishing Protocols on Surface Roughness, Flexural Strength, and Phase Transformation of High-Translucent 5 mol% Yttria-Partially Stabilized Zirconia

Abstract Objectives This study evaluated surface roughness, biaxial flexural strength, and phase transformation of 5Y-PSZ after grinding and polishing with different protocols. Material and Methods Two commercial 5Y-PSZ, Lava Esthetic (L) and Cercon xt (C), were used and divided into 3 groups: LC and CC represented unpolished control groups; LE and CE were polished with protocol I (EVE DIASYNT® PLUS HP following with EVE DIACERA RA); and LJ and CJ were polished with protocol II (Superfine diamond bur following with Jota ZIR Gloss polishing kit). Surface roughness was evaluated after polishing step-by-step with a contact-type profilometer. After high-gross polishing, the specimens were subjected to biaxial flexural strength test, crystallographic microstructure analysis using an X-ray diffractometer (XRD), and surface micro-topography using scanning electron microscopy (SEM). Statistical Analysis Surface roughness differences after each step and biaxial flexural strength between groups were evaluated with one-way ANOVA, followed by Bonferroni post-hoc analysis. Changes in surface roughness across four different time points within groups were assessed using one-way repeated measures ANOVA, followed by Bonferroni post-hoc analysis. Results After high-gross polishing, both polishing protocols showed significantly lower surface roughness than the grinding group (p &lt; 0.05). The LE and CE groups exhibited the highest surface roughness values, which were significant differences from the LJ and CJ groups (p &lt; 0.05). The LE group showed significantly lower biaxial flexural strength compared to the LC group (p &lt; 0.05). However, there was no statistically significant difference in the CE and CJ groups compared to the control group (p &gt; 0.05). Furthermore, all polishing protocols did not change the phase transformation of zirconia. Conclusion Polishing protocol II provided a smoother surface than the protocol I after high-gross polishing, while the biaxial flexural strength of materials remained unaffected.

Виявлення впливу шорсткості та радіального зазору на характеристику осьового багатоступеневого компресора

The operation of gas turbine engines inevitably increases the blade roughness and tip clearance in multistage axial compressors. The result is an increase in its thermogasodynamic parameters. The reason for the increase in the roughness of the blades and the tip clearance can be various factors: clogging of the flow part of the compressor (adhesion and deposition of dust on the surface of the blades), erosion due to the arrival of hard sand grains in the flow part, etc. The subject of this study is thermogasodynamic processes in the flow part of a multistage axial compressor, based on the presence of flow part removal. The goal is to develop a methodology for forecasting and researching the influence of the blade surface roughness and increased tip clearance on the overall characteristics of a multistage axial compressor. A twelve-stage axial compressor was used as the research object. The guiding vanes of the first four stages and the inlet guiding vanes depend on the rotation frequency. As a result, it was not possible to investigate the influence of the surface roughness of the blades and the increased tip clearance on the overall characteristics of the multistage axial compressor. The calculation of the characteristics of an axial multistage compressor with simulation of different levels of roughness and increased tip clearance in comparison with its initial values and obtained several indicators of changes in thermogasodynamic parameters and characteristics of the compressor with changes in roughness (ks = 3 μm, ks = 20 μm, ks = 40 μm) was performed. and tip clearance (Δr=1%, Δr=2%, Δr=5%). The scientific and practical novelty of the obtained results arises from the following: the method of calculating the thermogasdynamic parameters and characteristics of an axial multistage compressor has been improved, which makes it possible to evaluate the effect of the roughness of the surfaces of the blades and the increased tip clearance; new data were obtained regarding the change in the compressor characteristics at different levels of roughness and the size of the tip clearance.

Impact of air‐polishing with erythritol on exposed root dentin: A randomized clinical trial

AbstractIntroductionThe effects of air‐polishing on exposed root dentin surfaces are largely unknown, as there are only few studies which show heterogeneous results. Thus, this study was to investigate roughness changes of exposed dentin surfaces after air‐polishing and the influence of subsequent polishing with cup and paste.MethodsTotally 54 teeth with exposed root dentin surfaces were treated using a split‐mouth design by either air‐polishing with erythritol and a rubber cup with polishing paste on the test side, or rubber cup and paste alone. Teeth were finally cleaned using a sonic tooth brush. Impressions were taken at relevant time points and replicated using epoxy resin. The resulting casts were profilometrically analysed to obtain the average surface roughness (sRa) and maximum peak‐to‐valley height (sRz), which are given as the mean ± standard deviation in μm.ResultsAfter air‐polishing, in comparison to the baseline, there was a slight but significant increase in sRa (0.168 ± 0.143, p &lt; 0.001), but sRz did not change (−0.471 ± 4.857, p = 0.936). Subsequent polishing with cup and paste and cleaning with a sonic toothbrush did not reduce the surface roughness (sonic toothbrush‐air‐polishing, sRa −0.044 ± 0.081, p = 0.218; sRz −0.551 ± 3.563, p = 0.903).ConclusionThe use of erythritol led to a slight increase in the roughness of the dentin surface, which was not reduced by polishing with a cup and paste. Polishing paste did not seem to conceal surface irregularities.

In vitro evaluation of surface roughness of titanium abutments after air polishing with different abrasive powders

AbstractObjectivesThe purpose of this study was to evaluate the effects of air polishing with sodium bicarbonate and erythritol powders on surface roughness and morphological changes in titanium abutments.MethodsA total of 45 grade V titanium discs were divided in three groups: Group A (Control) air polished with air/water; Group B, air polished with sodium bicarbonate powder; and Group C, air polished with erythritol powder. After air polishing, the samples' roughness (Sa) in micrometres were analysed with an optical profilometer. The samples' surface morphology study was conducted via scanning electronic microscope (SEM). Data were described using mean and standard deviation of roughness values (Sa). Inferential analysis was performed using the ANOVA multiple comparison test followed by Tukey's post hoc test. Both tests used a 5% level of significance.ResultsAfter air polishing, average roughness of group A, B and C were 0.036, 0.046 and 0.037 μm, respectively, with statistically significant differences between groups A and B (p &lt; 0.05). No statistically significant differences were found between group A and group C, as well as between group B and C (p &gt; 0.05). As for the morphology analysis, damages to the titanium surface were only observed in group B.ConclusionsThe study indicates that air polishing with erythritol powder maintains titanium abutment integrity better than sodium bicarbonate, which increased surface roughness and caused damage. Erythritol is preferable for minimizing surface alterations and maintaining morphological stability.

Experimental investigation of pool boiling performance on a coated copper surface using a two-step non-thermal plasma process

In this study, a stable hydrophilic thin layer resembling SiOx is formed on the copper surface by combining plasma polymerization using hexamethyldisiloxane (HMDSO) and Ar plasma activation. The effect of coating on the Heat Transfer Coefficient (HTC) and Critical Heat Flux (CHF) at two different subcooling temperatures is investigated through pool boiling experiments. It is found that the HTC and CHF of the modified surface improved by 42 % and 97 %, respectively. The chemical composition of the coating, as well as changes in surface roughness, wettability, and porosity, are studied using the Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectrometer (EDX), Fourier Transform Infrared (FT-IR) spectroscopy, and contact angle measurement. The boiling/cooling experiments for the plasma-coated surface show good stability, demonstrating that the surface characteristics remain stable even after three boiling/cooling cycles.

Hydrophobization of Cold Plasma Activated Glass Surfaces by Hexamethyldisilazane Treatment.

The objective of this study was to investigate the modification of glass surfaces by the synergistic combination of cold plasma and chemical surface modification techniques. Glass surface hydrophobicity was obtained as a result of various plasma and deposition operational conditions. The mechanisms governing the hydrophobization process were also studied. Glass plates were activated with plasma using different gases (oxygen and argon) at different treatment times, ranging from 30 to 1800 s. Then, the plasma-treated surfaces were exposed to hexamethyldisilazane vapors at different temperatures, i.e., 25, 60, and 100 °C. Complete characterization, including contact angle measurements, surface free energy calculations, 3D profilometry, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and scanning electron microscopy, was accomplished. It was found that the extent of the hydrophobicity effect depends on both the plasma pre-treatment and the specific conditions of the hexamethyldisilazane deposition process. Plasma activation led to the formation of active sites on the glass surface, which promoted the adsorption and reaction of hexamethyldisilazane species, thereby inducing surface chemical modification. Longer plasma pre-treatment resulted in stronger modification on the glass surface, resulting in changes in the surface roughness. The largest water contact angle of ≈100° was obtained for the surface activated by argon plasma for 1800 s and exposed to hexamethyldisilazane vapors at 25 °C. The changes in the surface properties were caused by the introduction of the hydrophobic trimethylsilyl groups onto the glass surface as well as roughness development.

Examining the impact of slide burnishing parameters on the 3D surface features of medium carbon steel

Burnishing is a non-cutting finishing technique in which pressure is applied to plastically deform the irregularly distributed surface materials. In this process, the peaks of the surface are pressed into the valleys with a hard tool, resulting in a smoother surface with improved properties. The influence of brunishing parameters such as brunishing force, feed rate and number of passes on the 3D surface roughness of medium carbon steel was analyzed. An orthogonal L9 array Taguchi design was used to create a robust experiment. A CNC milling machine and a confocal microscope were used to grind and measure the workpiece surface. The topography roughness responses Sq, Sv, Sz and Sa were used to evaluate the roughness changes. The optimal parameters for brunishing were a feed rate of 0.05 m/min, 2 passes and a force of 80N for Sq and Sa and a force of 100N for Sv and Sz. This research is expected to provide insights into optimizing mass finishing processes to improve surface integrity, contributing to advances in manufacturing and materials science.

Evaluation of wind farm performance over heterogeneously rough terrain using large eddy simulation

We evaluate the effect of an abrupt change in the surface aerodynamic roughness height on a wind farm sited on it using the large eddy simulation (LES). Compared to a wind farm sited on a uniformly rough surface, the alteration in aerodynamic surface roughness from a rough to smooth value leads to substantial changes in the first-order and second-order turbulent statistics. Specifically, the rough-to-smooth surface roughness transition leads to an acceleration of the flow downstream of it, which affects the wake recovery and wind farm power production. Different velocity deficits are formulated considering different definitions of “upstream” velocity. The usual deficit, i.e., the difference between the overall wind farm upstream velocities and downstream of a turbine, attains negative values near the ground, rendering it difficult to model within the usual Gaussian radial-shape framework. An alternative definition, i.e., the difference in velocity at the same location with and without turbines on a heterogeneous surface, consistently yields positive values and is amenable to Gaussian shape-based modelling. The power generation decreases as the step change in surface roughness progressively moves into the wind farm. Maximum power is produced when all turbines are placed downstream of the surface roughness jump and minimum power is generated for a homogeneously rough surface when the entire wind farm is placed on the rough surface.

The Influence of Topographical Variations on Wind Turbine Wake Characteristics Using LES

A detailed understanding of the characteristics of wind-turbine wakes over complex terrain is crucial for designing efficient wind farms. Complexity of the terrain can be due to changes in elevation (due to, e.g., hills/valley/cliffs), and changes in the surface roughness (due to land types, e.g. fallow/cultivated/forested). We employ large-eddy simulations to study the evolution of a wind-turbine wake sited at different locations on a gradual two-dimensional hill with and without an abrupt transition in its surface aerodynamic roughness. A turbine placed at the foot of the hill, midway between the foot and the peak, and at the hill peak behave very differently when compared against each other. For a homogeneously rough surface, the profile of the velocity deficit normalized by the inflow velocity at the hill peak height shows that the wake recovers fastest for a turbine placed at the midway location. For a heterogeneously rough surface, however, the wake recovery for a turbine at the midway location is not significantly faster than that for a turbine at the hill-foot. The surface heterogeneity accelerates the flow downstream, which affects the wake recovery, due to which the deficits over heterogeneously rough surfaces are typically larger than for homogeneous surfaces. The turbulence intensity as well as the turbulence intensity added due to the presence of the turbine are affected by the position of the turbine as well as the surface roughness heterogeneity. The observed differences between the rates of wake recovery are only partly explained by the pressure gradient of the background flow over the hill in the absence of the wind turbine. The pressure drop over a region from one diameter upstream to five diameters downstream of the turbine explains the wake recovery for the turbines sited on homogeneously rough surface but not on a heterogeneously rough surface.

A multifractal model for predicting the permeability of dual-porosity media with rough-walled fractures and variable cross-sectional pore channels

The seepage of rock strata is greatly influenced by the pore network and fracture network; however, the prediction of permeability becomes challenging due to the changes in the cross section of pore channels and the morphology of fractures. In this study, a novel pore-fracture permeability model based on a fractal theory is proposed, and the analytical solutions of the model are given. In contrast to the traditional smooth parallel plate and uniform cross section straight capillary, this model not only considers the roughness of the fracture surface, but also the cross section variation and tortuosity of the pore channel. The comparisons between the calculated results and the experimental data verify the reliability of this model. The quantitative analyses of microscopic parameters indicate a positive correlation between the permeability and the fractal dimension, size, and proportion of pores and fractures. Conversely, there is a negative correlation with roughness, tortuosity, and cross-sectional changes. The range in which the seepage contribution of pores cannot be ignored is determined. Two logarithmic relationship expressions for permeability are presented. This study contributes to explore the effects of the geometry and morphology of the pore-fracture media on seepage and supplements the studies on the permeability models.

Effect of Bleaching Agents on Composite Resins with and without Bis-GMA: An In Vitro Study.

The objective was to evaluate the change in color, hardness, and roughness produced by carbamide peroxide (CP) at two different concentrations on two resins. The 16% or 45% CP was applied to 66 resin discs with and without Bis-GMA. The color was measured with a spectrophotometer, and ΔEab and ΔE00 were calculated. Microhardness tester and SEM were used. In both composites, the a* and b* coordinates tended to be red and yellow, respectively, and were significant in the Bis-GMA group (p < 0.05). The ΔEab and ΔE00 were higher in the composite with Bis-GMA, regardless of the treatment received (p < 0.05). The microhardness was reduced in both composites regardless of the PC concentration compared to the control (p < 0.05). The 45% CP reduced the microhardness in the resin group with Bis-GMA compared to 16% CP (p < 0.001) but was not significant in the resin without Bis-GMA (p = 1). An increase in roughness was directly proportional to the concentration of CP, and it was more notable in the composite without Bis-GMA. The composite with Bis-GMA showed a greater tendency to darken than the one without Bis-GMA. The surface hardness of the composite was reduced in both composites and was not influenced by CP concentration in the composite without Bis-GMA. Bleaching is a common procedure nowadays. It is important to know how CP affects composites to establish a prognosis of the treatments in terms of color change, roughness, and hardness.

Effect of MoS2 nanoparticles on the properties of Ni-W-SiC composite coatings

To improve the comprehensive protection performances of Ni-W-SiC composite coatings, we successfully manufactured Ni-W-SiC-MoS2 composite coatings using an electrodeposition technique on a 7075 aluminum alloy surface. We analysed the changes in microhardness, wear resistance, corrosion resistance, surface morphology and roughness of the composite coatings upon the addition of MoS2 nanoparticles. A microscopic characterisation of the Ni-W-SiC-MoS2 coatings was carried out by scanning electron microscope and atomic force microscope. The elemental composition was analysed by energy dispersive spectroscopy. The grain size was calculated by X-ray diffraction. The microhardnesses of the Ni-W-SiC-MoS2 composite coatings were evaluated by a microhardness tester, the wear resistance was tested by a rotary friction tester, and the corrosion resistance was evaluated using an electrochemical workstation. The tests indicate that the addition of MoS2 nanoparticles has significant effects on the micromorphology and grain size of Ni-W-SiC,and that they can uniformly codeposit with SiC nanoparticles in the Ni-W coating, exerting a synergistic effect on the improvement in the performance of the composite coating. When the amount of added MoS2 is 8 g/L, the Ni-W-SiC-MoS2 coating has the smallest grain size and highest microhardness (917.6 HV). Its corrosion resistance is considerably improved compared to that of the Ni-W-SiC coating. When the MoS2 concentration is 6 g/L, the Ni-W-SiC-MoS2 coating has the highest content of MoS2 nanoparticles, the friction coefficient reaches the minimum (0.24), and the wear resistance is best.

Mathematical Model of Vibration-Centrifugal Processing of Parts Using Loose Abrasive

The article presents some new theoretical and experimental solution of a scientific and applied problem of technological support for vibratory centrifugal processing of complex-profiled parts in a bulk abrasive environment. This solution aims to increase productivity while ensuring the desired quality of the processed surfaces. The authors have developed a mathematical model that describes the action of abrasive particles on the surface of the parts, taking into account the parameters of the granular abrasive medium based on Voigt’s law. This allows the description of dynamic processes in the processing environment for a wide range of material types. The natural frequencies of oscillations of the processed medium layer have been determined, which depend on the amplitude of its vibrations for different densities of soft and hard materials of the processed medium and the medium with linear-elastic properties. The methodology includes the use of test equipment to conduct experimental research on the process, which involves determining changes in specific metal removal rates and surface roughness using the frequency converter Altivar 71 with the PowerSuite v.2.5.0 software.

Effect of Electrolytic Plasma Polishing on Surface Properties of Titanium Alloy

Electrolytic plasma polishing (EPPo) is an advanced metal surface finishing technology with high quality and environmental protection that has broad application prospects in the biomedical field. However, the effect of EPPo on surface properties such as corrosion resistance and the wettability of biomedical titanium alloys remains to be investigated. This paper investigated the changes in surface roughness, surface morphology, microstructure, and chemical composition of Ti6Al4V alloy by EPPo and their effects on surface corrosion resistance, wettability, and residual stress. The results showed that Ra decreased from 0.3899 to 0.0577 μm after EPPo. The surface crystallinity was improved, and the average grain size increased from 251 nm to more than 800 nm. The oxidation behavior of EPPo leads to an increase in surface oxygen content and the formation of TiO2 and Al2O3 oxide layers. EPPo can significantly improve the corrosion resistance and wettability of titanium alloy in simulated body fluid and eliminate the residual stress on the sample surface. The surface properties are enhanced not only by the reduction in surface roughness but also by the formation of a denser oxide film on the surface, changes in the microstructure, an increase in surface free energy, and the annealing effect developed during EPPo. This study can provide guidance and references for applying EPPo to biomedical titanium alloy parts.

Composite effects of residual stress and hardness gradient on contact fatigue performance of rough tooth surfaces and optimization design of detailed characteristic parameters

Residual stress and hardness gradient significantly affect the contact fatigue failure process of rough tooth surfaces, and the meticulous design of their characteristic parameters can help improve the fatigue resistance of gears. In this paper, an efficient computational method for rough tooth surface contact is established based on the reconstruction modeling of asperities and mixed lubrication analysis. By comprehensively considering the effects of residual stress and hardness gradient, the Dangvan multiaxial fatigue criterion is adopted to predict and analyze the contact fatigue life of the gear surface. The correlation between the surface residual stress, maximum residual stress depth, surface hardness, and effective hardening layer depth, among other characteristic parameters, and the contact fatigue performance of tooth surfaces is established. The results show that: (1) Increasing the magnitude of surface residual compressive stress and surface hardness can significantly reduce the risk of fatigue failure in the near-surface layer of the gear. To achieve the same fatigue performance, there is a linear negative correlation between the design values of the two parameters. (2) Affected by the double stress peaks in the rough tooth surface stress field, the maximum residual stress depth significantly affects the depth at which the highest failure risk occurs. With changes in roughness, the optimal design value of the maximum residual compressive stress depth changes from about 0.5 times the Hertzian contact half-width depth in the subsurface layer (Sa < 0.2 μm) to about 15 μm in the near-surface layer (Sa > 0.4 μm). (3) Considering both process cost and gear surface fatigue resistance, the design threshold for the effective hardening layer depth should be greater than the Hertzian contact half-width. This paper establishes a composite correlation between the meticulous characteristic parameters of residual stress, hardness gradient, and the contact fatigue performance of tooth surfaces, providing theoretical support for optimal design of tooth surface anti-fatigue performance.

Assessing the Impact of Various Decontamination Instruments on Titanium and Zirconia Dental Implants: An In Vitro Study.

This study investigates the impact of various instrumentation techniques on material removal and surface changes in titanium (Ti)- and zirconia (Zr) implant discs. Ti- and Zr discs were subjected to standardized experiments using various instruments including airflow, ultrasound, carbide, and diamond burs. Instrumentation was performed for 60 s with continuous automatic motion. Abrasion and changes in surface roughness were assessed using profilometry, while scanning electron microscopy was used to examine morphological changes and particle size. Carbide burs predominantly caused abrasion on Ti discs, while diamond burs caused more abrasion on Zr discs. The Ti discs were more susceptible to surface changes. However, among the materials tested, machined Zr discs treated with diamond burs produced the largest particle. In certain cases, a statistical significance (p < 0.05) was observed between the groups, while in others, there was no considerable difference among the means (p > 0.05). These results highlighted the statistical significance of our findings. These results found diverse alterations in surface characteristics of Ti- and Zr discs due to different instruments, with carbide and diamond burs causing notable effects. The findings highlight the need for a careful balance between promoting healing and minimizing harm during implantoplasty.

Experimental investigation on the boiling heat transfer characteristic of copper surfaces with different hydrophilicity

Surface hydrophilicity has a significant effect on boiling heat transfer. In order to systematically investigate the influence of hydrophilic degree on the boiling heat transfer performance, seven different surfaces with gradually changing contact angles (CAs) were prepared using the chemical etching technology. Meanwhile, Visual studies on pool boiling of four of these different hydrophilic surfaces were conducted using a high-speed camera at atmospheric pressure, with deionized water as the working fluid. The influence laws of the hydrophilicity coefficient and relative wall superheat on the enhancement of boiling heat transfer are systematically summarized. It is shown that the boiling heat transfer coefficient (HTC) and critical heat flux (CHF) of the heating surface increased as the CA decreased. Owing to its vertically and horizontally interlaced nanorods and nanoflower structures, the surface oxidized by NaOH/(NH4)2S2O8 has higher surface roughness and larger phase change heat transfer area, resulting in a super-hydrophilic property of the copper surface and a faster bubble detachment frequency. The CHF and boiling HTC were 1.16 and 1.59 times that of the untreated surface, respectively, and the onset of nucleate boiling was advanced by 3.1 K, greatly enhancing boiling heat transfer and exhibiting better heat transfer performance.