Surface Melting Research Articles

Research on Key Technologies of Jewelry Design and Manufacturing Based on 3D Printing Technology

In conjunction with the swift enhancement of China’s economic prowess, the demand for jewelry among the populace is gradually evolving towards personalized, customized, and intricate designs. Traditional manufacturing approaches are increasingly inadequate to meet these evolving demands. However, the advent of 3D printing technology presents a viable solution for the direct fabrication of such sophisticated jewelry. To this end, the conceptualization of personalized jewelry inspiration is initiated, followed by the implementation of parametric design using SolidWorks 2018 software. Subsequently, 3D printing technology is employed to materialize the jewelry directly. Results indicate that the “Guardian” jewelry model, crafted through the parametric modeling method, exhibits a commendable design, and adheres to processing requirements following a comprehensive risk analysis. The strategic adjustment of the jewelry’s position effectively reduces the required support, circumventing the necessity of adding support to critical surfaces. The surface of the Selective Laser Melting (SLM)-manufactured “Guardian” jewelry boasts a lustrous finish, showcasing optimal overlap between pillars and excellent connectivity among pores. Minimal powder adherence on the surface is observed, enabling direct utilization post-sandblasting, polishing, and plating. This establishes a solid foundation for the direct application of SLM-manufactured personalized jewelry.

Polar Low Circulation Enhances Greenland's West Coast Cloud Surface Warming

AbstractMass loss of the Greenland Ice Sheet (GrIS) plays a major role in the global sea level rise. The west coast of the GrIS has contributed 1,000 Gt of the 4,488 Gt GrIS mass loss between 2002 and 2021, making it a hotspot for GrIS mass loss. Surface melting is driven by changes in the radiative budget at the surface, which are modulated by clouds. Previous works have shown the impact of North Atlantic transport for influencing cloudiness over the GrIS. Here we used space‐based lidar cloud profile observations to show that a polar low circulation promotes the presence of low clouds over the GrIS west coast that warm radiatively the GrIS surface during the melt season. Polar low circulation transports moisture and low clouds from the sea to the west of Greenland up over the GrIS west coast through the melt season. The concomitance of the increasing presence of low cloud in fall over the Baffin Sea due to seasonal sea‐ice retreat and a maximum occurrence of Polar low circulation in September results in a maximum of low cloud fraction (∼14% at 2.5 km above sea level) over the GrIS west coast in September. These low clouds warm radiatively the GrIS west coast surface up to 80 W/m2 locally. This warming contributes to an average increase of 10 W/m2 of cloud surface warming in September compared to July on the GrIS west coast. Overall, this study suggests that regional atmospheric processes independent from North Atlantic transport may also influence the GrIS melt.

Molding Process Retaining Gold Nanoparticle Assembly Structures during Transfer to a Polycarbonate Surface.

The immobilization of gold nanoparticle (AuNP) linear surface assemblies on polycarbonate (PC) melt surface via molding is investigated. The order of the particle assemblies is preserved during the molding process. The assemblies on PC exhibit plasmonic coupling features and dichroic properties. The structure of the assemblies is quantified based on Scanning Electron Microscopy (SEM) and image analysis data using an orientational order parameter. The transfer process from mold to melt shows high structural fidelity. The order parameter of around 0.98 reflects the orientation of the lines and remains unaffected, independent of the injection direction of the melt relative to the particle lines. This is discussed in the frame of fountain flow during injection molding. The particles were permanently fixed and withstood the injection molding process, detachment of the substrate, and extraction in boiling ethanol. The plasmonic particles coupled strongly within the dense nanoparticle lines to produce anisotropic optical properties, as quantified by dichroic ratios of 0.28 and 0.52 using ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy. AuNP line assemblies on a polymer surface may be a basis for plasmonic devices like surface-enhanced Raman scattering (SERS) sensors or a precursor for nanowires. Their embedding via injection molding constitutes an important link between particle-self-assembly approaches for optically functional surfaces and polymer processing techniques.

Data Sets Formation on the Physical Properties of Oxide Scale Components for Theoretical Assessment of Efficiency Parameters of Laser Cleaning of Carbon Steels and Related Processes

There is a need in machine-building industries nowadays to automate technologies, in particular, laser ones, to remove surface oxide layers – mill scale, rust – from steel products/pieces in order to improve the energy effectiveness of processing. Herewith, a theoretical assessment method for the intensity of heating of the oxide layer and the phase transition in it can be used to optimize laser cleaning (LC) of the steel surface. To realize this, it is possible to use some calculation and modeling procedures that require, as a first step, the data collection and verification on the temperature-dependent properties of iron-containing condensed phases, as possible components contained, in particular, in scale, which is typically widespread into various metal products. In this regard, the formation of database for characteristics of oxide scale components by the way of selection of information on thermophysical (including optical) properties of the components mentioned and of steel base, which are required for a reliable calculation of the thermal efficiency parameters of the technology for laser cleaning of carbon steels, as well as such actively developed related technologies as laser cutting, drilling, coating remelting, etc., was chosen as the task of our research. An analytical overview of published experimental data made it possible to systematize information on a number of transport and other physical properties of iron-containing components at ambient pressure, including thermal conductivity (k) and diffusivity (a), density ρ, irradiation absorptance and integral emissivity in the temperature range from T ≈ 298 K to the melting temperatures of oxide and metal phases and above them. At the same time, a preliminary thermochemical estimation shows (on the calculated data) the existence of such thermodynamically stable forms of the condensed phase in the heating spot of scale layers during its LC at the melting point and above it, as Fe3O4, FeO, and Fe, which is consistent with known experimental data. Comparison of the values of a calculated by us (using the published values of k, ρ and molar heat capacity and using extrapolation in the high-temperature region) for the types of scale components under consideration with a set of experimental values of this parameter in current literature revealed the presence of differences for both oxide and metal phases. These new values make it possible to fill in a gap in the temperature range T = 1600–1800 K that existed in the data on the thermal diffusivity. The value of a = (0.83–0.92)·10–6 m2/s was also calculated for liquid iron oxide for the T ≈ 1800 K, which was not measured experimentally, that, obviously, prevented modeling of not only laser surface processing, melting and cleaning of steels, but also calculations in the field of metallurgical and other technologies, which are characterized by the presence of iron oxide melts during heating.

Machine Learning Molecular Dynamics Shows Anomalous Entropic Effect on Catalysis through Surface Pre-melting of Nanoclusters.

Due to the superior catalytic activity and efficient utilization of noble metals, nanocatalysts are extensively used in the modern industrial production of chemicals. The surface structures of these materials are significantly influenced by reactive adsorbates, leading to dynamic behavior under experimental conditions. The dynamic nature poses significant challenges in studying the structure-activity relations of catalysts. Herein, we unveil an anomalous entropic effect on catalysis via surface pre-melting of nanoclusters through machine learning accelerated molecular dynamics and free energy calculation. We find that due to the pre-melting of shell atoms, there exists a non-linear variation in the catalytic activity of the nanoclusters with temperature. Consequently, two notable changes in catalyst activity occur at the respective temperatures of melting for the shell and core atoms. We further study the nanoclusters with surface point defects, i.e. vacancy and ad-atom, and observe significant decrease in the surface melting temperatures of the nanoclusters, enabling the reaction to take place under more favorable and milder conditions. These findings not only provide novel insights into dynamic catalysis of nanoclusters but also offer new understanding of the role of point defects in catalytic processes.

Machine Learning Molecular Dynamics Shows Anomalous Entropic Effect on Catalysis through Surface Pre‐melting of Nanoclusters

AbstractDue to the superior catalytic activity and efficient utilization of noble metals, nanocatalysts are extensively used in the modern industrial production of chemicals. The surface structures of these materials are significantly influenced by reactive adsorbates, leading to dynamic behavior under experimental conditions. The dynamic nature poses significant challenges in studying the structure–activity relations of catalysts. Herein, we unveil an anomalous entropic effect on catalysis via surface pre‐melting of nanoclusters through machine learning accelerated molecular dynamics and free energy calculation. We find that due to the pre‐melting of shell atoms, there exists a non‐linear variation in the catalytic activity of the nanoclusters with temperature. Consequently, two notable changes in catalyst activity occur at the respective temperatures of melting for the shell and core atoms. We further study the nanoclusters with surface point defects, i.e. vacancy and ad‐atom, and observe significant decrease in the surface melting temperatures of the nanoclusters, enabling the reaction to take place under more favorable and milder conditions. These findings not only provide novel insights into dynamic catalysis of nanoclusters but also offer new understanding of the role of point defects in catalytic processes.

A Review on Laser Beam Shaping Application in Laser Powder Bed Fusion

Laser powder bed fusion (L‐PBF) is extensively adopted in the aerospace and automobile industries for producing metallic components. The L‐PBF process involves rapid melting and solidification of metallic powders using a laser source to produce dense parts. Most industrial L‐PBF systems use a fiber‐based laser source that emits a Gaussian beam distribution. However, the conventional Gaussian beam used in L‐PBF processes presents inherent limitations that can impact the quality and properties of the final products. This review aims to provide a theoretical background of laser beam shaping techniques and explores the application of alternative beam shapes in L‐PBF. It investigates how different beam profiles affect the melt pool geometry, process stability, productivity, mechanical properties, microstructure, and surface roughness of fabricated parts. Additionally, it discusses different types of beam‐shaping techniques and elements utilized to generate distinct beam shapes. Furthermore, different constraints and limitations that hinder the full exploitation of beam shaping are critically discussed. By analyzing the impact of beam shaping in L‐PBF, this review provides insight into optimizing the AM process, enhancing part quality, and improving processing performance. It will also help readers to overview the research gaps, challenges, and promising future directions in laser beam shaping applications in L‐PBF.This review comprehensively covers and presents the current research trend of laser beam shaping applications in L‐PBF. It delves into the opportunities, challenges, limitations, and futures prospects of beam shaping applications. Furthermore, presents the methods and techniques used to modulate the laser beam profile, including spatial and temporal.This article is protected by copyright. All rights reserved.

Experimental assessment of the heat shielding performance by the integration of phase change material and liquid cooling plate

This research focuses on innovative stealth equipment by integrating a liquid cooling plate and phase change material (PCM), and the temperature rise on the cold surface and PCM melting rate is reported to illustrate the PCM thermal behavior in lifting the heat shielding performance. Results show that the integrated PCM system is effective in delaying the temperature rise within a certain time. A slower temperature rise on the cold surface is found at the first 1200 s, and a significant acceleration in the temperature rise is given within 1200 s ∼ 2000 s as the heat flood breaks through the PCM layer. The PCM melting rate increases rapidly and then rises slowly, and the complete melting time is shortened as increasing heat power. The heat shielding performance is significantly reduced with increasing the liquid flow rate, and the influence of the coolant temperature on the temperature rise becomes more and more prominent as the completion of the PCM melting process. A slower temperature rise is observed at the lower PCM phase transition temperature, and a further increase in the PCM covering layer has little influence on the temperature rise at the initial stage.

Comparison of the Erosive Wear Resistance of Ductile Cast Iron Following Laser Surface Melting and Alloying

This article presents research results on the influence of the laser surface melting and alloying processes on the erosive wear resistance of ductile cast iron. For the research, an EN-GJS 350-22 ductile cast iron surface was laser-melted and laser-alloyed with titanium powder in an argon and nitrogen atmosphere. Solid-particle erosion tests were carried out on the laser-melted and -alloyed surface layers and the base material according to the ASTM G76-04 standard with 30° and 90° impingement angles. The erosive wear resistance results were correlated with Vickers hardness and microstructural test results with the use of SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), and XRD (X-ray diffraction). The mechanisms of erosive wear were also analyzed for the laser-treated surface layers and the base material. The research showed that the laser melting and alloying processes with titanium powder had a positive effect on the hardness and erosive wear resistance of the ductile cast iron surface due to microstructure modification. Moreover, despite the lower hardness of the laser-alloyed surface layers, their composite microstructure had a positive impact on the erosive wear resistance in comparison to the laser-melted surface layers.

Enhancing poly(lactic acid)/maleated polypropylene blend with magnesium oxide catalyst: a reactive blending approach for improved mechanical properties

Some defects of polylactic acid (PLA), especially its poor mechanical properties, were modified using a minimum content of non-biodegradable maleated polypropylene (MAPP). To this end, first, the amount of MAPP was optimized, which was 20 wt.%. Second, MgO was used as a new catalyst to improve the exchange reactions between active groups in both polymers in a reactive blending process. Tensile and izod analyses showed that, compared to neat PLA, with a slight decrease in modulus and tensile strength, elongation at break, and impact resistance were improved in the presence of 20 and 0.1 wt.% of MAPP and MgO, respectively. This improvement in mechanical properties can be related to the exchange reactions between two polymers and the formation of PLA-MAPP block copolymers. MFI and WDCA analyses demonstrated the increase in melt flowability and surface hydrophilicity of the resulting blends, respectively. DSC analysis showed that the Tg values of both polymers approached each other in the presence of catalyst. Also, the elimination of cold crystallization of PLA and the decrease in the Tm and crystallinity of both polymers are clear reasons for the miscibility of the alloy. TEM displayed the proper dispersion of MgO nanoparticles within the polymer matrix, and in addition, the XRD test also proved the decrease in the crystallinity of both polymers and appropriate miscibility of the samples containing 20 and 0.1 wt.% of MAPP and MgO, respectively. These results can promise the design of a compound with the maximum amount of PLA for further use in various industries.

Palaeo-environmental significance of evaporative calcite crusts in the Untersee Oasis, East Antarctica

Abstract Secondary carbonate precipitates on the surface of clasts have rarely been reported from Antarctica. Here, we infer the origin, age and palaeo-environmental significance of the calcite crusts in the Untersee Oasis, East Antarctica. The distribution of calcite crusts, which are up to 1 mm thick, is limited to locations with residual snow patches, and they have some of the highest δ18O (up to +17.4‰ Vienna Standard Mean Ocean Water (VSMOW)) and δ13C (up to +14.6‰ Vienna Pee Dee Belemnite (VPDB)) compositions of any carbonate deposits in terrestrial polar environments. Their δ18O and δ13C values are substantially enriched with respect to the isotopic values expected from equilibrium precipitation from the δ18O and δ13CDIC (DIC = dissolved inorganic carbon) of snow meltwater. The formation of the calcite crusts is ascribed to the evaporation of residual snow meltwater and the low relative humidity and strong winds, favouring a kinetic isotope effect. The 14C age distribution of the calcite crusts (1550 cal yr bp to modern) provides a minimum age for ice retreat and drainage of the palaeo-lake in Aurkjosen Cirque. However, in this polar desert environment in which surface melting is limited, the calcite crusts require sufficient snow accumulation and air temperatures warm enough to generate meltwater, and their age distribution corresponds to the late Holocene warm-wet climate period.

Effects of Different Oxidation Methods on the Wetting and Diffusion Characteristics of a High-Alumina Glass Sealant on 304 Stainless Steel.

Glass-to-metal seals are a very important element in the construction of vacuum tubes, electric discharge tubes, pressure-tight glass windows in metal cases, and metal or ceramic packages of electronic components. This paper presents the influence of different pretreatment methods on the high-temperature wettability of 304 stainless steel by high-alumina glass sealing. The pretreatment of the steel included laser surface melting and pre-oxidizing. The bonding characteristics of glass and stainless steel directly depend on the wettability in terms of the measured wetting angle, the type of oxide formed at the stainless steel surface, and the microstructural changes during the manufacturing process. The oxide film thickness on the stainless steel surface was evaluated to determine the optimal parameters. The film was wetted with high-alumina glass powder at different temperatures. The results showed that pre-oxidation decreased the wetting angle from 56.2° to 33.6°, while for the laser-melted surface, the wetting angle decreased from 49.8° to 31.5°. Scanning electron microscopy (SEM) revealed that the oxide film on the laser-melted surface was thicker and denser than that formed on the pre-oxidized surface. The present work shows that laser surface melting has a greater beneficial influence on the wetting and diffusion characteristics of 304 stainless steel sealed by high-alumina glass.

Influence of Supraglacial Lakes on Accuracy of Inversion of Greenland Ice Sheet Surface Melt Data in Different Passive Microwave Bands

The occurrence of Supraglacial Lakes (SGLs) may influence the signals acquired with microwave radiometers, which may result in a degree of uncertainty when employing microwave radiometer data for the detection of surface melt. Accurate monitoring of surface melting requires a reasonable assessment of this uncertainty. However, there is a scarcity of research in this field. Therefore, in this study, we computed surface melt in the vicinity of Automatic Weather Stations (AWSs) by employing Defense Meteorological Satellite Program (DMSP) Ka-band data and Soil Moisture and Ocean Salinity (SMOS) satellite L-band data and extracted SGL pixels by utilizing Sentinel-2 data. A comparison between surface melt results derived from AWS air temperature estimates and those obtained with remote sensing inversion in the two different bands was conducted for sites below the mean snowline elevation during the summers of 2016 to 2020. Compared with sites with no SGLs, the commission error (CO) of DMSP morning and evening data at sites where these water bodies were present increased by 36% and 30%, respectively, and the number of days with CO increased by 12 and 3 days, respectively. The omission error (OM) of SMOS morning and evening data increased by 33% and 32%, respectively, and the number of days with OM increased by 17 and 21 days, respectively. Identifying the source of error is a prerequisite for the improvement of surface melt algorithms, for which this study provides a basis.

Peeling off behavior of centimeter-level molten pool subjected to subsonic tangential airflow during laser ablation process

In this paper, a computational fluid dynamics model considering the interaction between subsonic tangential airflow and centimeter-level molten pool was established to investigate the melt peeling off behavior during laser ablation process. The results showed that the airflow resulted in violent fluctuations on the surface of molten pool and then flowed upward at a velocity of 2–10.5 m/s, accelerating the surface melt to move upward. A liquid column was formed and elongated slender along the metal surface pushed by the subsonic tangential airflow. An upward-bending tail appeared at the end of the liquid column, which was accelerated up to 6 m/s and then cut off by the airflow, making the melt peel away from the molten pool. Compared with the partial melt peeling off at 0.3 Ma, almost all of the melt was pushed out of the molten pool to peel off when the airflow velocity was increased to 0.5 Ma. When the airflow velocity was further increased to 0.8 Ma, the metal on the surface was accelerated in short time, leading to the peel-off occurring in advance. In addition, the melt temperature decreased due to the forced convection cooling effect of airflow. When the melt solidified, the solid-liquid interfacial tension generated in the liquid column provided tangential force conducive to cutting off the liquid column and peeling off. The decrease rate of the melt temperature with time accelerated significantly and then expedited the melt solidifying and peeling off when the airflow velocity was increased to 0.5 Ma. The decrease rate further accelerated and the temperature decrease occurred earlier at 0.8 Ma, reaching a stable state in a shorter time.

Research on directional solidification combined with electron beam melting and refining for recycling of FGH4096 alloy scraps

The constraints of traditional manufacturing techniques have led to the generation of a considerable amount of waste superalloy, causing substantial resource wastage. The primary concern with waste superalloys lies in the excessive presence of inclusions and impurity elements, rendering them unsuitable for further utilization. This study proposes the use of directional solidification combined with electron beam melting and refining (EBMR) to prepare FGH4096 superalloy ingots (Φ120 mm), which offers a promising approach to produce large-sized powder superalloy master alloy ingots with high-purity and high homogeneity. It is found that the secondary dendrite arm spacing and the size of the γ’ phase in the alloy are significantly reduced after EBMR treatment. The concentration of O and N can be decreased to 5.7 and 0.6 ppmw, respectively. The size of inclusion can be reduced below 8.69 μm and the inclusion numbers reduce by over 50 % compared with both conventional ingots. A droplet transfer mode and melt convection mode mechanism have been proposed, which accurately predicts the melting temperature and melt flow. A quantitative study is conducted on the influence of inclusion density, the contact angle between inclusions and melt, and the surface tension of the melt on capillary forces. The results indicate that the capillary forces between inclusions in the melt range from 1.8 × 10−19 N and 1.9 × 10−17 N. Furthermore, the collision-aggregation behavior of inclusions in the melt is discussed, and an estimate of the tendency of inclusion collision-aggregation is provided. The enrichment of inclusions in the EBMR ingot is primarily the result of turbulent collision. The Marangoni effect and the extremely high surface temperature of the melt promote the collision and agglomeration of inclusions, causing them to accumulate rapidly at the melt surface. Moreover, the thorough removal of inclusions through the decomposition and dissolution process of the electron beam offers theoretical backing for the preparation of superalloys through electron beam melting and high-purity refining.

Effect of horizontal magnetic field position on oxygen distribution in CZ silicon crystal growth

The horizontal magnetic field-assisted Czochralski(CZ) method is gaining significant popularity in the semiconductor industry for producing 200 mm semiconductor-grade silicon wafers. In this study, the impact of the horizontal magnetic field position on the oxygen content and radial uniformity of semiconductor-grade silicon crystals produced by the CZ method was investigated. Three-dimensional simulations were conducted using finite element software to calculate the melt convection and oxygen content before and after adjustment of the magnetic field position, respectively. The simulations results predicted a decrease in the oxygen content of the crystals following the adjustment of the magnetic field position from 0 to 75 mm below the free surface, and this was experimentally verified. The velocity distribution of the free melt surface exhibits better uniformity when lowering the magnetic field position. The influence of the magnetic field position on the temperature distribution and Marangoni flow in the melt was investigated, and the result of oxygen concentration difference identified the adjustment of the magnetic field position promoted the greater Marangoni flow below the free melt surface, which promoted the volatilization of SiO gas and thus reduced the oxygen concentration in the silicon ingot. Therefore, adjusting the position of the magnetic field is an effective way to increase the Marangoni flow and to obtain semiconductor-grade silicon crystal with lower oxygen content and better oxygen radial homogeneity.

Spatio-Temporal Variations of Surface Melt Over Antarctic Ice Shelves using SCATSAT-1 Data

Surface melting is a significant issue in Antarctica, affecting glacier movements and climate change. During summer, surface meltwaters from ponds circulate over ice shelves, causing mass loss. These melt water percolates down to shelf through crevasses and affects the iceshelf instability or break the ice shelf. Antarctica experiences a surface melting increase of around 3.5 million square kilometres for every one-degree rise in summer temperature. In this study we use remote-sensing data sets to assess the spatial and temporal distribution of surface melt over Antarctic ice shelves. We use microwave brightness temperature (Tb) to evaluate surface melting on ice shelves. Total four ice shelves from East and West Antarctica were selected for research due to their significant surface melting issues. The study estimated cumulative melt days over these ice shelves for year 2017 and 2018, and investigated melt variations over transect profiles. It was found that year 2018 showed increased amount in melt days in some regions of selected ice shelves.

The effect mechanism of laser beam defocusing on the surface quality of IN718 alloy prepared by laser powder bed fusion

The surface quality issue of the laser powder bed fused (LPBF-ed) parts deteriorates the mechanical properties. Laser beam defocusing (LBD) can effectively improve the surface quality. To reveal the effect mechanism of LBD on the surface quality of the LPBF-ed parts, a laser powder bed fusion (LPBF) numerical model is established. Based on the calculated results, the formation process of the surface defects such as bulges, depressions, partially melted powders and spatters and the corresponding melt pool dynamic behaviors are investigated. The effects of LBD on the melt pool dynamic behaviors during the surface defects formation and the track width are discussed. The results show that LBD can improve the surface quality by reducing Marangoni force and recoil pressure to reduce bulge height and depression depth, increasing track width to decrease partially melted powders, and increasing surface tension and reducing kinetic energy to decrease spatters.

The effect of shot peening on the contact fatigue performance of C40 steel gears after laser surface melting

In this paper, shot peening (SP) was employed as a post-processing technique for the laser surface melted (LSMed) gear. The aim was to improve the contact fatigue performance of laser surface melting+shot peened (LSMSPed) gears. The microstructure, surface roughness, residual stress, microhardness of C40 steel gears before and after SP treatment were characterized using scanning electron microscopy, x-ray diffraction stress analyzer, contour measuring instrument, and hardness tester. Fatigue test of gear was carried out with a Forschungsstelle für Zahnräder und Getriebebau (FZG) testing machine. Following the laser surface melting (LSM) treatment, a molten layer was observed on the gear teeth surface. The experimental results indicated that SP induced a hardened layer with a certain thickness and plastic deformation on the surface of LSMed gears. Importantly, as the SP parameters increased, there’s a corresponding reduction in both the average grain diameter and the maximum grain diameter. The reduction was most pronounced when the shot diameter reached its maximum value. It’s worth noting that once the optimal threshold for SP parameters is surpassed, the residual compressive stress and microhardness on the LSMSPed gear surface do not exhibit a continuous growth trend. Furthermore, the rise in SP parameters resulted in a gradual increase in the surface roughness of LSMSPed gears, albeit to varying degrees. In light of the combined effects of grain refinement, residual compressive stress, microhardness, and surface roughness, the contact fatigue performance of LSMSPed gears improved with increasing SP parameters. Notably, when comparing the contact fatigue life of LSMed gears with that of LSMSPed gears, we observed a substantial enhancement. However, it’s essential to highlight that when the shot diameter reaches its maximum value, the contact fatigue life of the LSMSPed gear, somewhat unexpectedly, decreased. It emphasized to a certain extent the influence of surface roughness on the contact fatigue performance of LSMSP gears.

Comprehending the surface melt characteristics, calving processes, and seasonal ice velocity of Dålk glacier in Larsemann Hills, East Antarctica

Surface melting induces hydro-fracturing and deformational changes on the ice surface, which have a substantial impact on its dynamics and stability and therefore, comprehending these processes is crucial for ice sheet mass balance and stability. The present study is an attempt to understand the surface melt characteristics, seasonal ice movement, and calving processes of the Dålk glacier located in the Larsemann Hills of East Antarctica using multi-sensor remote sensing observations from 2017 to 2023. We identified and examined several melt features across the glacier and analysed their evolution during the study period. Frontal changes, calving events, and seasonal surface ice velocities of the glacier were also investigated during the study period. We found that the evolution and drainage of the melt features over the Dålk glacier is highly dynamic in nature with a significant inter-annual variability. We report substantial morphological changes in the ice doline structure that may be driven by the surface melt patterns, ice movement, and ice deformation in the region which also, affect the drainage of the nearby connected melt ponds and features. Several minor to very major calving events observed during the period due to immense disintegration processes during the preceding melting season that also affected the ice movement. We also highlight the need of monitoring and studying such melt features over the outlet glaciers that concerns the imminent catastrophic fragmentation and deformational changes over the glacier.