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The data on the experimental determination of surface tension coefficients ( sigma ) of tungsten carbides WC and WC-W sub(2)C by the force of simultaneous grinding their powders with iron powder in a RM 400 planetary mill are presented. Coefficients sigma are evaluated and confidence intervals of their expected values are determined.

The management of supracondylar fractures in children remains a challenging area of orthopedic practice. Medial comminution is a recognized complication that can result in unstable fracture patterns, which can pose challenges in diagnosis and management. However, when anticipated surgical treatment with an additional medial K-wire is administered, stable fixation is typically ensured. However, an additional radial comminution poses several challenges for reduction, alignment assessment, and pin configuration for stable fixation, as presented in this case. This case report presents a fracture pattern of a Gartland type 3 fracture with medial and lateral comminution that has not been sufficiently described previously and illustrates an effective pin configuration that has yet to be theoretically described.

As the intensity and depth of coal mining grow year by year, coal seam gas pressure increases and stope structures become more complex, which can easily cause coal and gas outburst. During the process of coal and gas outburst, a large amount of coal is broken and ejected, seriously threatening the safety of workers and coal mine production. Therefore, a multifunctional coal and gas outburst physical simulation test system was used to carry out three outburst tests under different gas pressures to study the particle size distributions and fragmentation characteristics of the ejected coal. The results showed that the relative intensity of outburst increased with gas pressure, but the increase rate decreased. Gas pressure also played a role in promoting the coal crushing. For the crushing product, the R–R (Rosin–Rammler) distribution model with high COD (coefficient of determination) was used to calculate the comminution energy at 0.35 MPa, while the fractal distribution model with high COD was used at 0.85 MPa and 2.00 MPa. When gas pressure increased, the basic shape of the R–R model curve remained unchanged, the probability density curve of fractal model changed from concave to nearly straight and then to convex and the basic shape of the cumulative distribution curve of fractal model remained constant. The values of α (uniformity coefficient) and xe (characteristic particle size) impacted on the R–R model and the values of Df (fractal dimension) and xmax (maximum particle size) impacted on the fractal model. Within a certain error range, the comminution energy could be approximated. The comminution energy increased with gas pressure, and the potential energy of crushing product decreased with the value of the n related to the crushing mechanism. There was a strong linear relationship between relative intensity of outburst and comminution coefficient. The combination of experiments and machine learning provided a new direction for outburst prediction and prevention at coal mine sites.

Soil production, through bedrock weathering, regulates landscape evolution, biogeochemical cycles, and societal sustainability, yet quantifying soil production rates (SPRs) remains difficult due to limited tools. Here, we present a new framework for measuring SPRs based on uranium comminution ages and validate this approach at a deep granitic weathering profile in subtropical South China. Measured (234U/238U) activity ratios increase with depth in soil and remain stable in saprolite. Using a 1D mass‐transport model, we resolve a SPR of 2.4 ± 0.4 m/Ma, which is consistent with independent estimates by U‐series and 10Be dating. Set by inherent α‐recoil processes, uranium comminution ages do not rely on environmental conditions (e.g., lithology and soil thickness) that present challenges to conventional tools such as 10Be. We expect our approach to contribute a tool that could expand measurements of SPRs—a key parameter of Earth surface systems—to broader landscapes where SPR measurements have been limited.

Ball milling is a representative mechanochemical strategy that uses the mechanical agitation-induced effects, defects, or extreme conditions to activate substrates. Here, we demonstrate that ball grinding could bring about contact-electro-catalysis (CEC) by using inert and conventional triboelectric materials. Exemplified by a liquid-assisted-grinding setup involving polytetrafluoroethylene (PTFE), reactive oxygen species (ROS) are produced, despite PTFE being generally considered as catalytically inert. The formation of ROS occurs with various polymers, such as polydimethylsiloxane (PDMS) and polypropylene (PP), and the amount of generated ROS aligns well with the polymers’ contact-electrification abilities. It is suggested that mechanical collision not only maximizes the overlap in electron wave functions across the interface, but also excites phonons that provide the energy for electron transition. We expect the utilization of triboelectric materials and their derived CEC could lead to a field of ball milling-assisted mechanochemistry using any universal triboelectric materials under mild conditions. Through contact-electro-catalysis (CEC), reactive oxygen species can be produced by chemically inert triboelectric materials in ball milling, enabling mechanoredox reactions with a broad selection of abundant triboelectric materials

Integrating different modification strategies into a single step to achieve the desired properties of metal–organic frameworks (MOFs) has been very synthetically challenging, especially in developing advanced MOF/polymer mixed matrix membranes (MMMs). Herein, we report a polymer–MOF (polyMOF) system constructed from a carboxylated polymer with intrinsic microporosity (cPIM-1) ligand. This intrinsically microporous ligand could coordinate with metals, leading to ~100 nm-sized polyMOF nanoparticles. Compared to control MOFs, these polyMOFs exhibit enhanced ultramicroporosity for efficient molecular sieving, and they have better dispersion properties in casting solutions to prepare MMMs. Ultimately, integrating coordination chemistries through the cPIM-1 and polymer-based functionality into porous materials results in polyMOF/PIM-1 MMMs that display excellent CO 2 separation performance (surpassing the CO 2 /N 2 and CO 2 /CH 4 upper bounds). In addition to exploring the physicochemical and transport properties of this polyMOF system, scalability has been demonstrated by converting the developed MMM material into large-area (400 cm 2 ) thin-film nanocomposite (TFN) membranes. Microporous polymer ligand provides particle size reduction, enhanced ultramicroporosity (3–4 Å), and better colloidal stability in the polymer–metal–organic framework (polyMOF) system. This leads to defect-free and scalable composite membranes for efficient CO2 separation.

The wear of cutting tools, cutting force determination, surface roughness variations and other machining responses are of keen interest to latest researchers. The variations of these machining responses results in change in dimensional accuracy and productivity upto great extent. In addition, an excessive increase in wear leads to catastrophic consequences, exceeding the tool breakage. Therefore, this article discusses the online trend of modern approaches in tool condition monitoring while different machining operations. For this purpose, the effective use of new sensors and artificial intelligence (AI) is considered and followed during this holistic review work. The sensor systems used for monitoring tool wear are dynamometers, accelerometers, acoustic emission sensors, current and power sensors, image sensors, other sensors. These systems allow to solve the problem of automation and modeling of technological parameters of the main types of cutting, such as turning, milling, drilling and grinding. The modern artificial intelligence methods are considered, such as: Neural networks, Image recognition, Fuzzy logic, Adaptive neuro-fuzzy inference systems, Bayesian Networks, Support vector machine, Ensembles, Decision and regression trees, k-nearest neighbors, Artificial Neural Network, Markov model, Singular Spectrum Analysis, Genetic algorithms. Discussions also includes the main advantages, disadvantages and prospects of using various AI methods for tool wear monitoring. Moreover, the problems and future directions of the main processing methods using AI models are also highlighted.

Nanofluids are efficient heat transfer media that have been developed over the past 27 years and have been widely used in the electronic microchannel, engine, spacecraft, nuclear, and solar energy fields. With the high demand for efficient lubricants in manufacturing, the application of nanofluids in machining has become a hot topic in academia and industry. However, in the context of the huge amount of literature in the past decade, existing review cannot be used as a technical manual for industrial applications. There are many technical difficulties in establishing a mature production system, which hinder the large-scale application of nanofluids in industrial production. The physicochemical mechanism underlying the application of nanofluids in machining remains unclear. This paper is a complete review of the process, device, and mechanism, especially the unique mechanism of nanofluid minimum quantity lubrication under different processing modes. In this paper, the preparation, fluid, thermal, and tribological properties of nanofluids are reviewed. The performance of nanofluids in machining is clarified. Typically, in friction and wear tests, the coefficient of friction of jatropha oil-based alumina nanofluids is reduced by 85% compared with dry conditions. The cutting fluid based on alumina nanoparticles improves the tool life by 177–230% in hard milling. The addition of carbon nanotube nanoparticles increases the convective heat transfer coefficient of normal saline by 145.06%. Furthermore, the innovative equipment used in the supply of nanofluids is reviewed, and the atomization mechanisms under different boundary conditions are analyzed. The technical problem of parameterized controllable supply system is solved. In addition, the performance of nanofluids in turning, milling, and grinding is discussed. The mapping relationship between the nanofluid parameters and the machining performance is clarified. The flow field distribution and lubricant wetting behavior under different tool-workpiece boundaries are investigated. Finally, the application prospects of nanofluids in machining are discussed. This review includes a report on recent progress in academia and industry as well as a roadmap for future development.

Spacecraft missions have observed regolith blankets of unconsolidated subcentimetre particles on stony asteroids 1 – 3 . Telescopic data have suggested the presence of regolith blankets also on carbonaceous asteroids, including (101955) Bennu 4 and (162173) Ryugu 5 . However, despite observations of processes that are capable of comminuting boulders into unconsolidated materials, such as meteoroid bombardment 6 , 7 and thermal cracking 8 , Bennu and Ryugu lack extensive areas covered in subcentimetre particles 7 , 9 . Here we report an inverse correlation between the local abundance of subcentimetre particles and the porosity of rocks on Bennu. We interpret this finding to mean that accumulation of unconsolidated subcentimetre particles is frustrated where the rocks are highly porous, which appears to be most of the surface 10 . The highly porous rocks are compressed rather than fragmented by meteoroid impacts, consistent with laboratory experiments 11 , 12 , and thermal cracking proceeds more slowly than in denser rocks. We infer that regolith blankets are uncommon on carbonaceous asteroids, which are the most numerous type of asteroid 13 . By contrast, these terrains should be common on stony asteroids, which have less porous rocks and are the second-most populous group by composition 13 . The higher porosity of carbonaceous asteroid materials may have aided in their compaction and cementation to form breccias, which dominate the carbonaceous chondrite meteorites 14 . The absence of fine regolith on the asteroid Bennu is due to the high porosity of its rocks, which compress rather than fragment after impacts and exhibit slow thermal cracking.

Owing to its efficiency and unique reactivity, mechanochemical processing of bulk solids has developed into a powerful tool for the synthesis and transformation of various classes of materials. Nevertheless, mechanochemistry is primarily based on simple techniques, such as milling in comminution devices. Recently, mechanochemical reactivity has started being combined with other energy sources commonly used in solution-based chemistry. Milling under controlled temperature, light irradiation, sound agitation or electrical impulses in newly developed experimental setups has led to reactions not achievable by conventional mechanochemical processing. This Perspective describes these unique reactivities and the advances in equipment tailored to synthetic mechanochemistry. These techniques — thermo-mechanochemistry, sono-mechanochemistry, electro-mechanochemistry and photo-mechanochemistry — represent a notable advance in modern mechanochemistry and herald a new level of solid-state reactivity: mechanochemistry 2.0. Mechanochemistry is the science of inducing a chemical reaction through the application of mechanical force. This Perspective focuses on combining traditional mechanochemistry with different energy inputs — heat, light, sound or electrical impulses — to advance mechanochemical synthesis.