Detailed Surface Research Articles

Res-NeuS: Deep Residuals and Neural Implicit Surface Learning for Multi-View Reconstruction

Surface reconstruction using neural networks has proven effective in reconstructing dense 3D surfaces through image-based neural rendering. Nevertheless, current methods are challenging when dealing with the intricate details of large-scale scenes. The high-fidelity reconstruction performance of neural rendering is constrained by the view sparsity and structural complexity of such scenes. In this paper, we present Res-NeuS, a method combining ResNet-50 and neural surface rendering for dense 3D reconstruction. Specifically, we present appearance embeddings: ResNet-50 is used to extract the appearance depth features of an image to further capture more scene details. We interpolate points near the surface and optimize their weights for the accurate localization of 3D surfaces. We introduce photometric consistency and geometric constraints to optimize 3D surfaces and eliminate geometric ambiguity existing in current methods. Finally, we design a 3D geometry automatic sampling to filter out uninteresting areas and reconstruct complex surface details in a coarse-to-fine manner. Comprehensive experiments demonstrate Res-NeuS’s superior capability in the reconstruction of 3D surfaces in complex, large-scale scenes, and the harmful distance of the reconstructed 3D model is 0.4 times that of general neural rendering 3D reconstruction methods and 0.6 times that of traditional 3D reconstruction methods.

Surface adsorption of L-phenylalanine on silver colloidal nanoparticles investigated by surface-enhanced Raman spectroscopy

L-phenylalanine (L-Phe) is one of three aromatic amino acids frequently used in numerous vibrational applications, including surface-enhanced Raman spectroscopy (SERS). Despite the wide applications, the spectral analyses and vibrational assignments of the Raman spectra of L-Phe based on surface adsorption on metallic nanosurfaces are limited. In this work, we report pH-dependent SERS of L-Phe adsorbed on borohydride-reduced silver colloidal nanoparticles, where the spectral changes upon protonation of amine group are understood as the modification in the surface adsorption via the carboxylate and amino group. In-plane and out-of-plane ring stretching and aromatic ν(CH) modes appear sensitive to the surface orientation of the phenyl ring, and the peripheral vibrational modes, including the stretching and bending of carboxylate and amine groups, are crucial to understanding the detailed surface adsorption mechanisms of L-Phe in anionic and zwitterionic forms depending on the solution pH. The pH-dependent intensity changes of the major ring stretching modes show that the surface pKa of L-Phe decreases to ∼6 from the bulk value of 9.13.

The possibility of clinical bonding between metal/ceramic brackets to zirconia: in vitro study.

Objective: The present study aimed to assess the bond strength and durability of six bonding agents concerning their application to metal or ceramic brackets and zirconia. Materials and Methods: Six resin cement bonding agents (XT, XTS, RSBU, RGBU, SBPM, and GMP) were chosen for this investigation. Specimens were either stored in distilled water at 37°C for 24h or subjected to 5,000 thermocycles before conducting a Shear Bond Strength (SBS) test. Statistical analysis of the SBS data was performed using three-way ANOVA and Games-Howell tests (α = 0.05). The Adhesive Remnant Index was examined, and the debonding surface details on brackets and zirconia were observed. Results: For metal brackets, all groups demonstrated clinically acceptable bond strength, irrespective of storage conditions, except for the XT group. Regarding ceramic brackets, all groups displayed acceptable bond strength after 24h of water storage. However, following thermocycling, a significant decrease in SBS was noted across all groups (p < 0.05), with SBPM exhibiting a higher bond strength. Three-way ANOVA analysis indicated that SBS values were notably influenced by each factor, and an interaction among the three independent variables was observed (p = 0.000). Conclusion: The reliable bond strength between ceramic brackets and zirconia was significantly lower after thermocycling compared to that of metal brackets and zirconia. SBPM exhibited consistent and robust bond strength between ceramic/metal brackets and zirconia across various storage conditions. Furthermore, the HEMA-free adhesive demonstrated a potentially more consistent bonding performance compared to the HEMA-containing adhesive employed in this study.

Detailed kinetic modeling of catalytic oxidative coupling of methane

The oxidative coupling of methane (OCM) at high temperature over monolithic Pt-based catalysts operated at short contact times is investigated as an attractive method for methane upgrading to higher value products like ethylene and acetylene. An experimental measurement campaign aiming at elucidating the effect of operation parameters on the catalyst performance revealed that lower N2 dilution, lower CH4/O2 ratio, and higher space velocities promote high C2 yields. A maximum C2 yield of 10 % with 94 % CH4 conversion was obtained at a CH4/O2 ratio of 1.1, 50 % N2 dilution, and a space velocity of 4.5 × 105 h−1. Since both heterogenous and homogenous gas-phase chemistry together are required for determining C2 formation pathways, a detailed OCM surface reaction mechanism over Pt is presented consisting of 26 species and 86 reactions that are consistent from the view of thermodynamics and micro-kinetic reversibility. The combination of this OCM surface mechanism with a detailed gas-phase mechanism allows a numerical micro-kinetic description of the experimental measurements. The simulations presented in this study suggest that C2 formation takes place in the gas-phase at temperature above 1200 K with both oxidative and pyrolytic pathways for methane dehydrogenation to form CH3 radicals, whose coupling results in C2H6, C2H4 and C2H2 formation. Furthermore, the simultaneous presence of sufficient oxygen content and heat are vital for high C2 species yields.

PPSurf: Combining Patches and Point Convolutions for Detailed Surface Reconstruction

Abstract3D surface reconstruction from point clouds is a key step in areas such as content creation, archaeology, digital cultural heritage and engineering. Current approaches either try to optimize a non‐data‐driven surface representation to fit the points, or learn a data‐driven prior over the distribution of commonly occurring surfaces and how they correlate with potentially noisy point clouds. Data‐driven methods enable robust handling of noise and typically either focus on a global or a local prior, which trade‐off between robustness to noise on the global end and surface detail preservation on the local end. We propose PPSurf as a method that combines a global prior based on point convolutions and a local prior based on processing local point cloud patches. We show that this approach is robust to noise while recovering surface details more accurately than the current state‐of‐the‐art. Our source code, pre‐trained model and dataset are available at https://github.com/cg‐tuwien/ppsurf.

Magnetocapacitance at the Ni/BiInO3 Schottky Interface.

We report the observation of a magnetocapacitance effect at the interface between Ni and epitaxial nonpolar BiInO3 thin films at room temperature. A detailed surface study using X-ray photoelectron spectroscopy (XPS) reveals the formation of an intermetallic Ni-Bi alloy at the Ni/BiInO3 interface and a shift in the Bi 4f and In 3d core levels to higher binding energies with increasing Ni thickness. The latter infers band bending in BiInO3, corresponding to the formation of a p-type Schottky barrier. The current-voltage characteristics of the Ni/BiInO3/(Ba,Sr)RuO3/NdScO3(110) heterostructure show a significant dependence on the applied magnetic field and voltage cycling, which can be attributed to voltage-controlled band bending and spin-polarized charge accumulation in the vicinity of the Ni/BiInO3 interface. The magnetocapacitance effect can be realized at room temperature without involving multiferroic materials.

Use of Pressure in Rotational Molding to Reduce Cycle Times: Comparison of the Thermomechanical Behavior of Rotomolded Reed/Polyethylene Composites

Rotational molding advantages include the production of a hollow part with no welding lines, either of small or big sizes, with no internal stresses and good surface details. However, the process is limited by the long cycle times, and its related high energy consumption. Different strategies can be followed to reduce such energy use. This work assesses the use of pressure inside the molds during the densification and cooling stages, finding reductions in overall cycle time of approximately 20%, because of the reduction in the heating time required but also to the increased cooling rate. The influence of such an approach on the production of composites with reed fibers has also been assessed, finding a similar trend towards cycle time reductions. The rotomolded samples’ thermomechanical and rheological behavior were determined, finding that viscosity was not affected due to the incorporation of air during the moldings; besides, the homogeneity of the composites increased due to the mold pressurization. The parts obtained show good aesthetics and good thermomechanical behavior along the entire temperature range studied, and particularly for 10% composites; higher fiber ratios should be prepared via melt compounding. Therefore, the mold pressurization allows us to reduce both oven and cooling times, which can be translated into an increase in productivity and a decrease in energy consumption, which are undeniably related to the increase in the products’ sustainability and cost.

Flatbed scanners as versatile tools for studying surface details of compression fossils

Flatbed scanners as versatile tools for studying surface details of compression fossils

Unravelling the kinetics, isotherms, thermodynamics, and mass transfer behaviours of Zeolite Socony Mobil - 5 in removing hydrogen sulphide resulting from a dark fermentative biohydrogen production process.

Research into the speciation of sulfur and hydrogen molecules produced through the complex process of thermophilic dark fermentation has been conducted. Detailed surface studies of solid-gas systems using real biogas (biohydrogen) streams have unveiled the mechanisms and specific interactions between these gases and the physicochemical properties of a zeolite as an adsorbent. These findings highlight the potential of zeolites to effectively capture and interact with these molecules. In this study, the hydrogen sulphide removal analysis was conducted using 0.8 g of the adsorbent and at various reaction temperatures (25-125 °C), a flow rate of 100 mL min-1, and an initial concentration of approximately 5000 ppm hydrogen sulphide. The reaction temperature has been observed to be an essential parameter of Zeolite Socony Mobil - 5 adsorption capacity. The optimum adsorption capacity attains a maximum value of 0.00890 mg g-1 at an optimal temperature of 25 °C. The formation of sulphur species resulting from the hydrogen sulphide adsorption on the zeolite determines the kinetics, thermodynamics, and mass transfer behaviours of Zeolite Socony Mobil - 5 in hydrogen sulphide removal and Zeolite Socony Mobil - 5 is found to improve the quality of biohydrogen produced in thermophilic environments. Biohydrogen (raw gas) yield was enhanced from 2.48 mol H2 mol-1 hexose consumed before adsorption to 2.59 mol H2 mol-1 hexose consumed after adsorption at a temperature of 25 °C. The Avrami kinetic model was fitted for hydrogen sulphide removal on Zeolite Socony Mobil - 5. The process is explained well and fitted using the Temkin isotherm model and the investigation into thermodynamics reveals that the adsorption behaviour is exothermic and non-spontaneous. Furthermore, the gas molecule's freedom of movement becomes random. The adsorption phase is restricted by intra-particle diffusion followed by film diffusion during the transfer of hydrogen sulphide into the pores of Zeolite Socony Mobil - 5 prior to adsorption on its active sites. The utilisation of Zeolite Socony Mobil - 5 for hydrogen sulphide removal offers the benefit of reducing environmental contamination and exhibiting significant applications in industrial operations.

Development of a High-Precision, Portable and Automated Mobile Laser Scanner for the Recording and Digitation of Texture and Micro-marks in Archaeological and Heritage Stone

The use of laser tools to digitise cultural heritage items is becoming more widespread but is generally limited to manual systems that rely on the user’s movement or expensive automated equipment that is designed to scan large items but is not always able to accurately measure or reproduce specific details of small size. In this paper we present the novel high-precision system PALLAS, which allows the automatic digitisation of three-dimensional detailed surfaces. The equipment has been built using a set of motors and linear axes, control electronics and a line laser scanner that can be moved along the XY working plane. It is battery-powered for ease of use in the field and uses a standard laptop to communicate via Wi-Fi network. Custom software has been developed to automatically calculate paths, control the movement and store the profiles generated by the scanner. The software can also be used to reconstruct the surface from the set of scanner profiles, allowing the XYZ coordinates of any point on the surface to be measured and to obtain areal roughness parameters to characterise the finish and texture of the stone surface. Preliminary results obtained from masons’ marks, rock engravings and petroglyphs are presented.

Chipped lithic artefacts from Paradimi and Krovili (Thrace, Northern Greece). Remarks from the 2020 surface investigations

The paper presents flaked lithic materials from two tell-type Neolithic sites Paradimi and Krovili located in Eastern Thrace. They were obtained during systematic and detailed surface surveys. All the collected lithic materials were examined and described. Some conclusions about processing and sources of raw materials were presented along with comparisons to other Neolithic sites in northern Greece.

Self-Terminated Surface Reconstruction of Lanthanum Nickelates Promotes Alkaline Oxygen Evolution

Oxygen evolution reaction (OER) itself is expected to have a strong impact on the state of the surface of the electrocatalyst, yet the actual structure of the surface under operating conditions is rarely considered while formulating structure-activity correlations in electrocatalysis. In this study, changes in the surface structure of Ruddlesden-Popper-type lanthanum nickelate, La2NiO4+δ, and the perovskite LaNiO3 are probed and contrasted using a series of complementary surface sensitive techniques, including XPS, HRTEM and O K-edge XAS. We found noticeable surface changes to occur on La2NiO4+δ after exposure its exposure to the alkaline electrolyte that is accompanied by the emergence of a strong Nin+/n+1 redox feature and the coincides with a 45-fold enhancement of the OER activity (at η = 370 mV) in 0.1 M KOH, as compared to the pristine La2NiO4+δ phase. We observe that the in situ formation of an amorphous nickel (oxy)hydroxide layer on the surface increases the electrochemically-active surface area of La2NiO4+δ and imparts a high stability of the catalyst under OER conditions (the formation of the amorphous layer self-terminates at ca. 3 nm). In addition, the transition from octahedral Ni sites (O h ) to square-planar Ni sites (D 4h ) in the reconstructed surface was observed using O K-edge X-ray absorption spectroscopy. Further, we found no evidence for any surface transformations in the perovskite-based catalyst LaNiO3 that also did not demonstrate any improvement in its activity over cycling. This work highlights the importance of a detailed surface analysis of the catalysts under operation to build robust structure-activity correlations for the metal oxides under electrochemical reaction conditions. Figure 1

(Invited) Novel Surface Reactions in Low-Temperature Regime for High-Aspect-Ratio Dielectric Etching

The most critical issue to achieve High-Aspect-Ratio (HAR) dielectric etching is the transport of both radicals and ions to the bottom of a feature [1]. Current HAR dielectric etching uses fluorocarbon and hydrofluorocarbon gases combined with high applied bias power. However, the etch rate drastically decreases at high depth due to the decline of radicals being supplied to the etch front. Alternative methods have long been required to solve this problem. To address the radical transport issue, we propose adopting a novel precursor with low molecular weight to enhance Knudsen transport. In addition, cryogenic temperature regimes are also known to enhance etch rates [2][3] but have not yet been implemented for HAR dielectric etching. In this work we evaluated a novel precursor in cryogenic temperature regime for HAR dielectric etching. For the first time, we demonstrate a synergy effect between cryogenic temperature and this novel precursor by successfully developing an innovative HAR dielectric etch process. We confirmed that this process is capable of etching beyond a ten-micron depth for a 3D-NAND channel hole with a hundred nanometer critical dimension in diameter, thus an aspect ratio of over one hundred to one. The key to enabling high etch rate is strongly correlated with the adsorption of the precursor on the surface, which is enhanced at cryogenic temperature. Detailed surface adsorption reaction mechanisms will be described in the conference. This new process not only enables higher etch rate, higher selectivity and higher aspect ratio etching capability, but also significantly shortens the process time with 84% carbon footprint reduction of greenhouse gas emissions.[1] K. Ishikawa, et al., Jpn. J. Appl. Phys. Vol. 57, No. 6S2, 06JA01, (2018).[2] T. Ohiwa, et al., Jpn. J. Appl. Phys. Vol.31, p.405, (1992).[3] R Dussart, et al., J. Phys. D: 47, 123001, (2014).

Microstructure Formations Resulting from Nanosecond and Picosecond Laser Irradiation of a Ti-Based Alloy under Controlled Atmospheric Conditions and Optimization of the Irradiation Process.

This paper presents a study and comparison of surface effects induced by picosecond and nanosecond laser modification of a Ti6Al4V alloy surface under different ambient conditions: air and argon- and nitrogen-rich atmospheres. Detailed surface characterization was performed for all experimental conditions. Damage threshold fluences for picosecond and nanosecond laser irradiation in all three ambient conditions were determined. The observed surface features were a resolidified pool of molten material, craters, hydrodynamic effects and parallel periodic surface structures. Laser-induced periodic surface structures are formed by multi-mode-beam nanosecond laser action and picosecond laser action. Crown-like structures at crater rims are specific features for picosecond Nd:YAG laser action in argon-rich ambient conditions. Elemental analysis of the surfaces indicated nitride compound formation only in the nitrogen-rich ambient conditions. The constituents of the formed plasma were also investigated. Exploring the impact of process control parameters on output responses has been undertaken within the context of laser modification under different environmental conditions. Parametric optimization of the nanosecond laser modification was carried out by implementing an advanced method based on Taguchi's parametric design and multivariate statistical techniques, and optimal settings are proposed for each atmosphere.

Theoretical study on the insertion reaction of CH(X2) into the oh bond in n-C4H9OH

CH radicals play an important role in the combustion of hydrocarbon. The insertion mechanism of a CH radical into the O-H bond of n-C4H9OH is investigated theoretically by a detailed potential energy surface calculation at the BHandHLYP/6-311++G(3df,2p) and CCSD(T)/6-311++G(d,p) (single-point) levels. Our results show that the CH radical attacks into the oxygen atom in n-C4H9OH to form a prereaction complex (COMP) to be followed by an insertion of the CH radical into the O-H bond of the n-C4H9OH molecule to form the low-lying intermediate IS1 (CH2OCH2CH2CH2CH3). This intermediate can isomerize to form IS2 (CH3OCH2CHCH2CH3), IS3 (CH3CH2CH2CH2CH2O), and IS4 (CH3CH2CH2CH2CHOH). These intermediates can decompose to yield 9 products (PR1-PR9) in which major ones are PR1 (CH2CH2CH2CH3 + CH2O), PR2 (CH2CHCH2CH3 + CH3O) and PR3 (CH2CHCH2OCH3 + CH3).

Online Scene CAD Recomposition via Autonomous Scanning

Autonomous surface reconstruction of 3D scenes has been intensely studied in recent years, however, it is still difficult to accurately reconstruct all the surface details of complex scenes with complicated object relations and severe occlusions, which makes the reconstruction results not suitable for direct use in applications such as gaming and virtual reality. Therefore, instead of reconstructing the detailed surfaces, we aim to recompose the scene with CAD models retrieved from a given dataset to faithfully reflect the object geometry and arrangement in the given scene. Moreover, unlike most of the previous works on scene CAD recomposition requiring an offline reconstructed scene or captured video as input, which leads to significant data redundancy, we propose a novel online scene CAD recomposition method with autonomous scanning, which efficiently recomposes the scene with the guidance of automatically optimized Next-Best-View (NBV) in a single online scanning pass. Based on the key observation that spatial relation in the scene can not only constrain the object pose and layout optimization but also guide the NBV generation, our system consists of two key modules: relation-guided CAD recomposition module that uses relation-constrained global optimization to get accurate object pose and layout estimation, and relation-aware NBV generation module that makes the exploration during the autonomous scanning tailored for our composition task. Extensive experiments have been conducted to show the superiority of our method over previous methods in scanning efficiency and retrieval accuracy as well as the importance of each key component of our method.

A Prospective Study of Dermoscopic and Ultrastructural Features of Vitiligo-Associated Leukotrichia.

Dermoscopic and ultrastructural features of vitiligo-associated leukotrichia (VAL) have not been well studied. This study is aimed at the dermoscopic and ultrastructural features of VAL. We present a cross-sectional study of VAL-related dermoscopic signs and their relationship with disease stages and duration of leukotrichia. Characteristics of hair surface and finer details including melanosomes, macrofibrils, and remnant nucleus were observed under Electron Microscopy (EM). One hundred and forty samples on distinct sites from 100 patients were collected. Among 75 VAL from the scalp, the prevalence of diameter diversity of leukotrichia (52.6% vs 8.1%), Pohl-Pinkus constrictions (34.2% vs 0), and depigmented hair roots signs (34.2% vs 8.1%) in patients with progressive vitiligo was much higher than that in patients with stable vitiligo (all P<0.05). The EM result of VAL showed that melanosomes were smaller with vesicles formation, reduced counts, and incomplete shape, and macrofibrils were irregularly arranged with widened spaces and vesicles formation. No conclusions about the histopathologic characteristics or dermoscopic-histopathologic correlation of the VAL. The dermoscopic signs of diameter diversity of leukotrichia, Pohl-Pinkus constrictions, and depigmented hair roots are related to progressive vitiligo. The process of melanin synthesis and formation of VAL are impaired at the early stage of VAL under Electron microscopy.

NerfCap: Human Performance Capture With Dynamic Neural Radiance Fields.

This paper addresses the challenge of human performance capture from sparse multi-view or monocular videos. Given a template mesh of the performer, previous methods capture the human motion by non-rigidly registering the template mesh to images with 2D silhouettes or dense photometric alignment. However, the detailed surface deformation cannot be recovered from the silhouettes, while the photometric alignment suffers from instability caused by appearance variation in the videos. To solve these problems, we propose NerfCap, a novel performance capture method based on the dynamic neural radiance field (NeRF) representation of the performer. Specifically, a canonical NeRF is initialized from the template geometry and registered to the video frames by optimizing the deformation field and the appearance model of the canonical NeRF. To capture both large body motion and detailed surface deformation, NerfCap combines linear blend skinning with embedded graph deformation. In contrast to the mesh-based methods that suffer from fixed topology and texture, NerfCap is able to flexibly capture complex geometry and appearance variation across the videos, and synthesize more photo-realistic images. In addition, NerfCap can be pre-trained end to end in a self-supervised manner by matching the synthesized videos with the input videos. Experimental results on various datasets show that NerfCap outperforms prior works in terms of both surface reconstruction accuracy and novel-view synthesis quality.

Stress-induced, debris-modulated friction and wear resistance performance of nanostructured Ni–Co coatings

Owing to their HCP structure and inherent resistance to deformation, Cobalt-containing alloys are often used for low-friction and wear-resistant purposes. Here, the tribological performance of nanostructured Nickel–Cobalt coatings with 0–83 wt% Co was investigated. Three Co-rich coatings with similar microhardness and grain sizes showed different friction and wear behaviors that cannot be solely attributed to the HCP phase fraction. The coating with the highest Co content of 83 wt% achieved the lowest wear rate. However, the lowest surface friction was observed in Ni-76 wt% Co with a large amount of wear debris covering the contact surface of its counterpart. Nevertheless, these debris led to micro-cutting of the coating and a high wear rate. Detailed surface investigation of these coatings and their counterparts revealed a significant difference in material transfer, distribution of wear products, and wear mechanisms. Our analysis showed that the tribological performance of Ni–Co coatings can be dominated by surface-related features (such as surface oxide integrity, tribofilm, and wear debris) and lattice internal stress over the underlying phase fractions.

Mathematical model of the condensation process in a cylinder of a piston engine

BACKGROUND: In recent years, there has been a trend of increasing activity towards the development of polar territories. A characteristic feature of the North is negative ambient temperatures that have a negative impact on the condition of piston engines of ground transport, mobile and stationary power plants and labor saving tools. An engine is the least adapted unit for use in such conditions. There is a chain of negative factors that consistently links negative ambient temperatures, in which the equipment is operated, and the condition of the mechanisms and engine systems. The primary link of this chain is condensation processes. The existence of condensation processes during low-temperature operation of the engine has been experimentally proved. The latter takes place when warming up in conditions of negative ambient temperatures. The question «How much water changes the state during the warm-up period?» arises. AIMS: Development of a mathematical model that makes possible to obtain unbiased information about the activity of condensation processes and to estimate the amount of water that changes the state during the warm-up period. METHODS: Solving the given tasks is based on classical theories describing operational processes of boilers. The high labor intensity and significant financial costs in organizing such experiments require the search for new research methods. Mathematical models help to solve the task of defining the mass amount of water condensing in a cylinder of a piston engine computationally. RESULTS: The mathematical model that is characterized by its adaptation to piston engines and is capable of determining the mass amount of water changing the state during the warm-up period iteratively, using the differences in partial pressures and the density of the mass flow of water condensate, has been developed. CONCLUSIONS: The existence of water has a negative impact on conditions of a piston engine. The information about the amount of water condensing in a cylinder during the warm-up period stimulates to continue studies in the field of motor oils watering, active acids formation and corrosive wear of surfaces of details.