Original Surface Research Articles

Assessment of a novel computed tomography ratio to characterize B2 glenoid morphology with total shoulder arthroplasty

BackgroundThe B2 glenoid poses significant challenges for reconstruction with shoulder arthroplasty. A variety of techniques has been used to quantify the B2 glenoid and is often used for surgical decision-making. The critical B2 glenoid ratio is a novel measure and is defined as the ratio between the paleoglenoid length (original glenoid surface) and the total glenoid length. This study aims to define inter and intrarater reliability of the critical B2 ratio and to compare it to conventional methods of measurement. MethodsA convenience sample of patients with Walch B2 glenoid morphology was generated from a prospectively collected multicenter shoulder arthroplasty registry. The axes of preoperative computed tomography (CT) images were reoriented in the scapular plane. Three sports medicine surgeons experienced in arthroplasty measured the critical B2 glenoid ratio in addition to posterior humeral subluxation, version, and glenoid bone loss at 2 timepoints greater than 1 week apart. Inter-rater and intra-rater reliability were calculated for all readers and CT measures with the intraclass correlation coefficient (ICC). The critical B2 glenoid ratio was compared to conventional measurements using Spearman’s rank correlation coefficients and receiver operating characteristic (ROC) curves. ResultsThe critical B2 glenoid ratio demonstrated good inter-rater reliability among the 3 measurers with ICCs of 0.89 and 0.799 for the 1st and 2nd measurement sessions, respectively. The critical B2 glenoid ratio showed excellent intrarater reliability for 2 of the measurers (ICC 0.933 and 0.98) and good intrarater reliability for 1 of the measurers (ICC 0.820). A significant correlation was observed between glenoid bone loss along Friedman’s line and the critical B2 ratio (P < .001). ROC curves found a B2 ratio = 0.4 was found to be an inflection point for 15° of neoglenoid (posterior erosion surface) retroversion. ROC curves to assess if humeral head subluxation >70% correlated to a threshold B2 ratio value revealed no significant threshold. ConclusionsThe critical B2 glenoid ratio is a novel and reproducible CT-based measure that is defined as the ratio between the paleoglenoid length and the total glenoid length. It has high reproducibility based on inter and intra-rater reliability among a group of shoulder surgeons. A critical B2 ratio of less than or equal to 0.4 correlates with significant neoglenoid retroversion and may be a threshold beyond which to avoid corrective eccentric reaming for anatomic shoulder arthroplasty.

Cotransport of different electrically charged microplastics with PFOA in saturated porous media

The fate and transport behavior of microplastics (MPs), emerging colloidal contaminant ubiquitous in natural environments, would be greatly affected by other copresent pollutants. PFOA (emerging surfactant pollutant) would interact with MPs after encounter with them in natural environments, which could alter the transport behavior of both pollutants. Relevant knowledge is still lacking, affecting accurate prediction the fate and distribution of these two emerging contaminants in natural porous media. The cotransport behavior of different surface charged MPs (negatively/positively charged, CMPs/AMPs) with PFOA (three concentrations ranging from 0.1 to 10 mg/L) in porous media in both 10 and 50 mM NaCl solutions thus was investigated in the present study. We found PFOA inhibited CMPs transport in porous media, while enhanced AMPs transport. The mechanisms leading to the altered transport of CMPs/AMPs caused by PFOA were found to be different. The decreased electrostatic repulsion between CMPs-sand induced by the decreased CMPs negative zeta potentials via the adsorption of PFOA led to the inhibited transport of CMPs in CMPs-PFOA suspension. The enhanced electrostatic repulsion between AMPs-sand due to the decreased positive charge of AMPs via the adsorption of PFOA together with steric repulsion induced by suspended PFOA resulted in the increased transport of AMPs in AMPs-PFOA suspension. Meanwhile, we found that the adsorption onto MPs surfaces also impacted the transport of PFOA. Due to the lower mobility of MPs than PFOA, the presence of MPs despite their surface charge decreased the transport of PFOA of all examined concentrations in quartz sand columns. This study demonstrates that when MPs and PFOA are co-existing in environments, their interaction with each other will alter the fate and transport behavior of both pollutants in porous media and the alteration is highly correlated with the amount of PFOA adsorbed onto MPs and original surface properties of MPs.

Laser Textured Superhydrophobic SiC Ceramic Surface and the Performance of Condensation Heat Transfer

Chemical modification is usually utilized for preparing superhydrophobic SiC surfaces, which has the problems of long processing time, high environmental contamination risk, and high cost. To enhance the condensation heat transfer efficiency of SiC, the superhydrophobic SiC surface was fabricated through laser texturing and heat treatment. In this study, the SiC surface was processed by laser texturing with a nanosecond laser, followed by heat treatment. Surface microstructures and compositions were investigated with SEM and XPS, and the heat transfer coefficient of the superhydrophobic SiC surface was tested. The results indicated that the laser-textured SiC surface had a super hydrophilic contact angle of 0°; after heat treatment, SiC ceramic became superhydrophobic (surface contact angle reaches 164°) because organic contamination on the original SiC surface could be cleaned by using laser texturing, which caused a chemical reaction and the formation of SiO2 on the surface. Moreover, the distribution of relatively low-energy SiOX was formed after heat treatment; then, SiC ceramic became superhydrophobic. Due to the formation of nanoscale sheet-like protrusion structures by heat treatment, the SiC superhydrophobic surface exhibited typical dropwise condensation, and the condensation heat transfer coefficient reached 331.8 W/(m2·K), which was 2.3 times higher than that of the original surface.

Accelerating surface remeshing through GPU-based computation of the restricted tangent face

High-quality mesh surfaces are crucial for geometric processing in a variety of applications. To generate these meshes, polyhedral remeshing techniques truncate Voronoi cells of the original surface and yield precise intersections, but the calculation is complicated. Some methods apply auxiliary points to construct Voronoi diagrams to simplify these techniques, thereby extracting co-planar facets to approximate the original surface. However, extracting these approximate facets from the constructed Voronoi diagram makes it inefficient and non-parallelizable. To this end, we propose an efficient GPU method for manifold surface remeshing, where the restricted tangent face (RTF) is utilized to approximate the original surface. By intersecting the pre-clipped Voronoi cell with the tangent plane, this method directly calculates the RTF of each point without any auxiliary points or traversing Voronoi cells. Moreover, to restrict the movement of points, we introduce a projection method based on the KNN strategy, where each point is projected onto the triangular facet in the original surface. Owing to the independence and non-interference of the RTF computation and projection of each point, our method is implemented in parallel on the GPU. Experimental results on various mesh surfaces demonstrate the superior performance of our method in the viability, effectiveness, and efficiency.

Analytical and numerical relaxation results for models in soil mechanics

A variational model of pressure-dependent plasticity employing a time-incremental setting is introduced. A novel formulation of the dissipation potential allows one to construct the condensed energy in a variationally consistent manner. For a one-dimensional model problem, an explicit expression for the quasiconvex envelope can be found which turns out to be essentially independent of the original pressure-dependent yield surface. The model problem can be extended to higher dimensions in an empirical manner. Numerical simulation exhibits well-posed behavior showing mesh-independent results.

Improved 3D Pavement Texture Reconstruction Method Based on Interference Fringe via Optimizing the Post-Processing Method

The surface quality of pavement has a significant influence on the driving comfort and the skid resistance performance of roads. The 3D pavement texture measurement provides the basis for engineers to calculate the pavement performance index, such as the international roughness index (IRI), the texture depth (TD), and the rutting depth index (RDI), of different types of pavements. The interference-fringe-based texture measurement is widely used because of its high accuracy and high resolution, by which the 3D texture measurement has excellent accuracy in measuring the texture of workpieces with a diameter of &lt;30 mm. When measuring the engineering products with a larger area (or larger areas), such as pavement surfaces, however, the accuracy is deficient because unequal incident angles due to the beam-divergence angle of the laser beam are ignored during the postprocessing of the measured data. This study aims to improve the accuracy of 3D pavement texture reconstruction based on the interference fringe (3D-PTRIF) by considering the influence of the unequal incident angles during postprocessing. It is found that the improved 3D-PTRIF has better accuracy than the traditional 3D-PTRIF, reducing the reconstruction errors between the measured value and the standard value by 74.51%. In addition, it solves the problem of a reconstructed slant surface, which deviates from the horizontal plane of the original surface. Compared to the traditional post-processing method, for the case of smooth surface, the slope can be decreased by 69.00%; for the case of coarse surface, the slope can be decreased by 15.29%. The results of this study will facilitate accurate quantifying of the pavement performance index by using the interference fringe technique, such as IRI, TD, and RDI.

Study on Wear Resistance Evolution of Cold-Rolled Strip Flatness Meter Surface-Strengthened Layer

Seamless flatness rollers are the core equipment for cold-rolled strip flatness detection. The change in wear resistance of the roller surface-strengthened layer has important guiding significance for the prediction of the roller surface life. The experimental results of the five rounds of friction and wear testing show that the volume–wear rate of the original roller surface is only 1.85 × 10−6 mm3 (N·M)−1. After the first grinding, the wear resistance of the roller surface decreased and the wear rate was approximately 2.76 × 10−6 mm3 (N·M)−1. After the second grinding, the wear morphology, wear rate and wear resistance of the samples in each round showed little difference. The average wear rate in the last three rounds of the test is 3.56 × 10−6 mm3 (N·M)−1 and the wear resistance is significantly lower than that of the previous two rounds of the test. The calculation shows that the original surface wear resistance is 32.92% higher than that of the surface after the first grinding, and the average wear resistance of the surface after the first grinding is 22.59% higher than that of the surface after the second, third and fourth grinding. With long-term use and repeated grinding repair, the roller surface will show a trend of wear resistance decline. When the wear resistance decreases to a certain degree, it will reach a stage of stability. These phenomena provide regular and quantitative references for the study of the life prediction of flatness meter rollers.

Experimental study on electrochemical machining of TC11 titanium alloy blades based on cylindrical array microstructure cathodes

Titanium alloys have a wide range of applications in aerospace, however, this material is very sensitive to changes in the flow field during electrochemical machining (ECM) and suffers from frequent short-circuiting and poor surface quality. Studies have shown that optimization and improvement of the cathode structure often improve the processing properties of the material. To process titanium alloy under a steady state, the laser processing system was used to prepare cylindrical array microstructure on the end surface of cathode. The comparison between the original and improved cathode was conducted in ECM experiments. The experimental results showed that serious flow marks existed on the original cathode processing surface. Within the range of processable voltage, short circuits occurred at the processing heights of 1.823 mm and 1.655 mm. The improved cathode can process a bright finish surface without flow marks and there were no short circuits. The influence of two microstructure arrangements on the blade surface quality was also investigated. Compared to inline cylindrical array (ICA) cathode. The processing gap equilibrium flow rate of the staggered cylindrical array (SCA) cathode is about 0.3 L/min higher. The average surface roughness of the blade hub was reduced from 1.632 µm to 0.574 µm. Additionally, there are multiple layers of electrolysis products adhering to the non-machined surface and the machined sidewall of the blade. The oxygen content of the outer layer is higher than that of the inner layer, and the oxygen content of the non-machined surface is significantly higher than that of the machined sidewall. The microstructure cathode designed in this paper realizes the stable processing of titanium alloy in passivation electrolyte.

EESD special issue: AI and data‐driven methods in earthquake engineering – (Part 1)

EESD special issue: AI and data‐driven methods in earthquake engineering – (Part 1)

Effect of CMAS attack behaviour on stress distribution in double-ceramic-layer thermal barrier coatings

Stress distribution has a significant effect on crack nucleation and propagation in thermal barrier coatings (TBCs). The stress distribution of different types of double-layer plasma-sprayed coatings, such as YbYSZ/YSZ (YbYSZ: Yb2O3-Y2O3 co-stabilised ZrO2; YSZ: Y2O3 stabilised ZrO2) and YbYSZ/EMAP-YSZ (EMAP-YSZ: embedded micron-agglomerated particle-YSZ) coatings, was numerically studied using the finite element method (FEM) under the condition of thermal shock experiments coupled with calcium-magnesium-alumina-silicate (CMAS) attack. The maximum stress increased with the increasing thickness of CMAS deposition when CMAS was deposited on the coated surface. Among the three coatings of YSZ, YbYSZ/YSZ, and YbYSZ/EMAP-YSZ attacked by CMAS, the stress change of the YbYSZ/EMAP-YSZ coating was lower when CMAS was deposited on the surface of the ceramic layer and penetrated 200 μm below the original surface but was worse after penetration up to 250 μm. Furthermore, traditional YSZ in a CMAS environment was also compared to demonstrate the thermal shock life of double-ceramic layer coatings in a better manner. The relationship among CMAS attack, thermal shock, temperature distribution, stress distribution, and cracking initiation of TBC systems has been clarified to provide significant insight in understanding the failure mechanism and important guidance for optimising TBCs to enhance their service life.

Isotropic plasma-thermal atomic layer etching of aluminum nitride using SF6 plasma and Al(CH3)3

We report the isotropic plasma atomic layer etching (ALE) of aluminum nitride using sequential exposures of SF6 plasma and trimethylaluminum [Al(CH3)3]. ALE was observed at temperatures greater than 200 °C, with a maximum etch rate of 1.9 Å/cycle observed at 300 °C as measured using ex situ ellipsometry. After ALE, the etched surface was found to contain a lower concentration of oxygen compared to the original surface and exhibited a ∼35% decrease in surface roughness. These findings have relevance for applications of AlN in nonlinear photonics and wide bandgap semiconductor devices.

Experimental Investigation of Engine Valve Train Friction Considering Effects of Operating Conditions and WPC Surface Treatment.

Reduction in friction ensures fuel economy, control on emissions and durability of components in internal combustion engines. A modern gasoline internal combustion engine was instrumented to determine the friction values at the cam-roller interface considering the effects of surface treatment and engine operating state. A series of tests under different operating speeds and lubricant inlet temperatures were undertaken using both an original surface roller and a Wonder Process Craft (WPC) surface-treated engine roller. The results clearly revealed a substantial reduction in friction magnitude for the WPC surface-treated engine roller in comparison to the original roller while operating under similar conditions, indicating their strong potential for employment in engines. An increase in friction with the rise in temperature was also observed for both types of rollers, whereas increased lubricant entraining velocity due to higher operating speed had the opposite impact. A considerable reduction in frictional drive torque ranging from 8% to 28% was observed by employing the WPC-treated roller in comparison to original/untreated roller at various operating conditions, which signifies the strong potential for employment of WPC surface treatment in the roller/follower valve train engines.

In Situ Formation of Li2SiO3-Li-NaCl Interface on Si and Its Effect on Hydrogen Evolution

Silicon has emerged as a competitive candidate for hydrolytic hydrogen production due to its high theoretical hydrogen yield, low cost, and on-demand availability. However, the hydrolysis reaction is extremely restrained by passivated SiO2, including the original one on the Si surface and the generated one during hydrolysis, and almost no hydrogen is produced in pure water. Herein, the original SiO2 surface has been effectively removed by milling micro-Si mixed with a small amount of Li metal and NaCl. An artificial soluble interface on Si has been established containing Li2SiO3, Li, and NaCl. Once micro-Si is placed into water, fresh Si surface can be exposed and a weak LiOH solution can be generated due to the fast dissolution of the interface layer, resulting in the rapid liberation of hydrogen gas. Accordingly, the modified micro-Si displays a significantly enhanced hydrogen production in pure water at 30 °C (1213 mL g-1 H2 within 3.0 h), which is 2.0 and 4.7 times higher than that observed for ball-milled Si and raw Si in 0.06 M LiOH solution, respectively. In addition, it also exhibited an outstanding operation compatibility for practical uses. This work has proposed a green, effective, and scalable strategy to promote hydrogen production from the hydrolysis of Si-based systems.

Polishing and Local Planarization High-Precision HDC Capsules by Four-Cup-Type Technology for Inertial Confinement Fusion

In inertial confinement fusion (ICF) experiments, high-density carbon (HDC) is being evaluated as an alternative to the current point-design ablator material (glow discharge plasma) due to its high density and optimal opacity, which leads to a higher energy efficiency and implosion stability. Chemical vapor deposition–coated HDC capsules have a near-perfect surface figure but a microscopically rough surface, so polishing is needed to achieve the required nanometer surface finish. Herein, HDC capsule polishing is investigated with modified four-cup-type polishing technology. The surface morphology, microstructures, and wall thicknesses of the polished capsules were examined by multiple techniques, such as an optical microscope, scanning electron microscope, X-ray radiography, and so on. The results show that the HDC capsules can be polished to a surface roughness less than 15 nm and a wall thickness nonuniformity of about 0.5 μm. The Raman spectra indicated that four-cup polishing had no obvious influence on the original surface crystallinity and phase composition of the HDC capsules. The crystallographic of the HDC capsules with different four-cup polishing times had no deterioration. This work plays an important role for the application of HDC capsules in ICF research.

Surface quality improvement of a laser-polished Co-free high entropy alloy prepared by selective laser melting

In order to improve the quality of the Co-free high entropy alloy surface, a Co-free high entropy alloy specimen prepared by selective laser melting was polished by laser in this work. Optimal laser polishing process parameters were explored, and the best surface roughness Sa value reached 0.4626µm, which is much lower than the original surface roughness. Through microscope, SEM, EDS and other tests, the surface quality after polishing is obviously improved The big improvement in high entropy alloy specimen’ surface quality has potential significance in promoting the application of this material in high precision situations.

Influence of Measurement Uncertainty in the Determination of Selected Rock Parameters-A Realistic Approach.

To determine and compare the measurement uncertainty of different geological-geotechnical testing methods, numerous test locations were selected in a hard rock quarry. Measurements were carried out along two vertical measurement lines perpendicular to the mining levels of an existing exploration. Along these lines, the rock quality basically varies due to weathering (decreasing influence with increasing distance from the original ground surface), but also due to the influence of the geological-tectonic conditions on site. The mining conditions (blasting) are identical over the considered area. The rock quality was examined as follows: as field tests, the rock compressive strength was determined by means of point load test and rebound hammer, as laboratory method the Los Angeles test (standard laboratory test for the determination of the mechanical rock quality) was used to identify the impact abrasion resistance. The statistical evaluation and comparison of the results allowed conclusions to be drawn about the contribution of the individual test methods to the measurement uncertainty whereas, in practice, a priori information can be applied complementarily. It shows that the influence on the combined measurement uncertainty u of the different methods due to the geological variability in horizontal direction reaches values between 17 and 32%, whereby the rebound hammer method shows the highest values. However, the highest influences on the measurement uncertainties are a result of the vertical direction due to weathering phenomena with percentages of 55 to 70%. For the point load test, the vertical direction shows the highest significance with an influence of approximately 70%. This leads to the conclusion that a higher weathering degree of the rock mass shows an increasing effect on the measurement uncertainty which needs to be considered using a priori information in measurements.

Incorporating machine learning models and remote sensing to assess the spatial distribution of saturated hydraulic conductivity in a light-textured soil

Saturated soil hydraulic conductivity (Ksat) is a key component in hydrogeology and water management. This study aimed at evaluating popular tree-based machine learning algorithms (Random forest (RF), Quantile random forest (QRF), Cubist (Cu), and Decision tree regression (DTr)) to assess the spatial distribution of Ksat in a sandy agricultural field. Soil surface reflectance derived from Landsat-8 (OLI/TIRS) (several remotely sensed data including original surface reflectances of spectral bands and 22 remote sensing indices) as well as limited ground measured soil data were used as predictor covariates. Using collected disturbed and undisturbed soil samples, physicochemical properties (Ksat, porosity, organic matter, and texture contents) were determined. Based on novel supervised feature selection, covariates including Landsat-8 spectral Band2, Band4, Band6, and Band7, normalized difference pond index (NDPI), normalized difference vegetation index (NDVI), and silt content were identified as the most important factors in Ksat prediction. Variable importance analysis showed Band7 and Band6 were explaining 54% of the total Ksat variation. The model evaluation, using five statistics cretria, Taylor diagram and the Kruskal–Wallis (KW) test, demonstrates the outperformance of RF being followed by QRF, Cu, and DTr models. Accordingly, the RF method combined with an optimized sampling approach provides the most accurate digital soil Ksat map. The uncertainty analysis showed no significant different trend in Ksat predictions by applying more dense datasets confirming original-limited data (n = 28) was efficient and sufficient to derive a reliable Ksat-map. The developed approach, which can be scaled up at a large scale, seems to be useful in modelling water flow and solute transport for water and nutrient management purposes toward precision agriculture.

Electrothermally excited plasma droplet evolution on the laser-patterned surface

Droplet behavior involving electrothermal coupling fields has gradually attracted the attention of researchers, one of which includes electrosurgical scalpels that often contact biofluids. However, the evolution of bio-droplets exposed to the surface of electrosurgical scalpels is not yet well understood. Here, we experimentally studied the effect of different heating temperatures on plasma droplets on the laser-patterned surface (LPS) and the original surface (OS) under defined direct-current (DC) or alternating-current (AC) electric fields. The results show that at a lower heating temperature, the evolution of plasma droplets was dominated by electrolysis. Oxygen bubbles generated on the papillae on the LPS in the DC field inhibited the targeted adsorption of plasma proteins on this surface. In contrast, in the AC field, only a small number of bubbles was generated, which is not sufficient to inhibit protein adsorption, leading to the formation of coagulation on the papillae after heating. At higher heating temperatures, the rapid formation of coagulation resulted in the suppression of electrolysis. The plasma proteins were then transported by the Marangoni flow causing coagulation to reach a thickness of stress mutation. Stress release over the entire coagulation caused its edges to bend and then detach from the papillae. Thus, the LPS exhibited excellent anti-adhesive properties to plasma droplets under electrothermal excitations compared to the OS. This study provides valuable information for understanding the mechanisms of contact behavior between biofluids and electrosurgical scalpels and demonstrates great promise for their anti-adhesive performance.

The Criterion of the Cassie–Baxter and Wenzel Wetting Modes and the Effect of Elastic Substrates on It (Adv. Mater. Interfaces 12/2023)

Wettability of Bio-Mimetic Microstructures In article number 2202439, Il Woong Park, Jonas M. Ribe, Maria Fernandino, and Carlos A. Dorao replicate bio-mimetic conical microstructures from a hard substrate onto an elastic substrate to explore the effect of microstructures on wettability. The cover art illustrates an elastic surface with replicated microstructures that can mimic the superhydrophobic behavior of the original hard surface. [NTNU Nano is acknowledged for support through the NTNU Nano Impact Fund.]

Enhanced catalytic activity for methanol synthesis from CO2 hydrogenation by doping indium into the step edge of Rh(211): A theoretical study

The doping of foreign metals can modify the electronic properties of the original catalyst surfaces, thereby changing the catalytic activity. Realistic surfaces possess many defects, such as step sites. Herein, the first-principles calculation is implemented to research how indium doping on stepped Rh(211) alters the catalytic activity for methanol synthesis. The calculated substitution energy shows that the indium atom tends to be doped at the step edge of Rh(211). Almost all species prefer to adsorb at the step-edge sites because the surface atoms at the step-edge possess the lowest coordination number. The electronic structure analysis demonstrates that the activation degree of CO2* chiefly relies on the charge transfer between CO2* and catalyst. Furthermore, the doped indium atoms make In/Rh(211) expose more H* adsorption sites and promote the relative stability of adsorbed species on In/Rh(211). Besides, the doping of indium significantly inhibits the generation of by-product CO*, and enables the activation barrier to be as low as 0.98 eV for the rate-determining step on In/Rh(211), which is much lower than that of some reported catalysts. The ultrahigh catalytic activity of In/Rh(211) might be attributed to the decrease of the work function induced by the doping of indium, enhancing the relative stability of reaction species and CO2* activation degree.