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Cu-free resin-based brake material filled with waste foundry resin-bonded sand (waste sand) was prepared using the hot-pressing method. The changes in the physical and chemical properties of Cu and waste sand during braking were investigated, and their role in resin-based composites was discussed. The effects of the content of waste sand on the hardness, impact strength, indentation hardness, elastic modulus, friction coefficient, wear rate, micro-scratch friction coefficient, scratch depth, residual depth, and wear mechanism of resin-based brake material were investigated. Cu-contained composites generate Cu 2 O when braking at high temperatures, which adversely affects the friction and wear properties. Compared to Cu, waste sand was found to be more favorable for the overall friction and wear properties of resin-based composites. This suggests that waste sand can be used as a substitute for Cu in brake material. Waste sand is beneficial for improving the friction coefficient and stability of brake material through the formation of a friction layer. This layer can significantly impact the wear mechanism of brake material, particularly at high temperature (250–350 ℃). The brake material with 10–15% waste sand indicates excellent heat-fade resistance. • Waste foundry sand have been successfully replaced copper in brake material. • The role of waste foundry sand and copper in brake material were comparatively studied. • The effects of waste sand on mechanical and tribological properties of brake material were investigated. • The brake material containing 10–15% waste foundry sand show excellent heat-fade resistance. [ABSTRACT FROM AUTHOR]

Facet joint osteoarthritis (FJOA) is associated with lumbar disc degeneration and has a significant role in the development of lumbar spinal stenosis (LSS). The relationship between various radiographic parameters and the grade of FJOA is not well understood. To explore radiographical parameters associated with FJOA in LSS without lumbar dynamic instability. Retrospective study analysis. A total of 122 patients diagnosed with LSS who visited our hospital between January 2015 and July 2022. We evaluated radiographic parameters of patients at L4-5 including lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), grades of FJOA, facet joint orientation (FO), facet joint tropism (FT), intervertebral height index (IHI) and the relative cross-sectional area (RCSA) of paraspinal muscles. Patients diagnosed with LSS between January 2015 and July 2022 were enrolled. Demographic characteristics and radiographic parameters were collected. Spinopelvic parameters were measured through the preoperative lateral image of the whole spine, including LL, PI, pelvic tilt, and sacral slope. Lumbar computed tomography scan and magnetic resonance imaging were collected to measure the FO, FT, IHI, and the RCSA of paraspinal muscles respectively. Patients were divided into three groups according to the severity of FJOA graded by the Weishaupt classification: grade 0 and grade 1 were group A, grade 2 were group B, and grade 3 were group C. All variables were compared among the three groups, while the relationship between parameters and grades of FJOA were also analyzed. A total of 122 patients were included. PI was significantly greater in group C compared to group A (p = 0.025) and group B (p=0.022). FT was significantly greater in group C compared to group A (p<.001) and group B (p<.001). The RCSA of multifidus in group A were significantly greater than that in group B (p=0.02) and C (p=0.002). Additionally, FO in group C were significantly lower than group A (p<.001) and group B (p=0.028). The IHI in group C was significantly lower than group A (p=0.017). The correlation analysis indicated that grades of FJOA was positively related to Age, BMI (body mass index), PI, LL and FT, while negatively related to IHI, FO, RCSA of multifidus and RCSA of psoas major. Furthermore, the logistics regression showed that FT, PI, and IHI were important influence factors for FJOA. The current study confirmed that FT, PI and IHI were significantly associated with grades of FJOA at L4-5. Additionally, longitudinal studies are needed to understand the causal relationship between these parameters and FJOA. [ABSTRACT FROM AUTHOR]

In this study, a high-temperature fretting wear prediction model was established for metal rubber, which was then validated through experiments. Initially, a three-dimensional numerical model of metal rubber was reconstructed, and statistical distribution of contact points and types of curved wires inside the virtual component was achieved. Meanwhile, a high-temperature fretting wear evolution model for curved wires was constructed by introducing a temperature function f(T), considering material thermal expansion, softening, and oxidation. Subsequently, the model was incorporated into the macro model, establishing a cross-scale predictive model for wear from micro-coil elements to component wear. Experimental validation demonstrated good prediction performance of the model, with a maximum wear mass prediction error of 14.81% and prediction errors below 10% for 80,000 cycles. [ABSTRACT FROM AUTHOR]

• Metal wire and cotton fibers are combined through ingenious weaving methods. • The combination of macroscopic and microscopic fibers makes SWCM have excellent durability and efficient emulsion separation performance. • For the first time, an emulsion separation simulation model has been established via computational fluid dynamics (CFD) to understand the SWCM emulsion separation mechanism. • The separation efficiency of the SWCM is above 99.98% only by gravity drive. Superhydrophobic materials have been extensively investigated for their ability to separate oil/water mixtures, but their fragile durability has limited further development in this field. In this study, a durable superhydrophobic wire-cotton-based material (SWCM) was prepared by weaving metal wire and cotton fiber and modifying it with a mixed poly(vinyl phenol) (PVPh)/1,3-phenylene bisoxazoline (PBO) solution, which exhibits both macro-frame and micro-aperture. The SWCM demonstrates remarkable separation efficiency (greater than99.98 %) for a variety of water-in-oil emulsions using only gravity drive. More importantly, computational fluid dynamics (CFD) simulations were conducted to investigate the separation mechanism of SWCM, revealing dynamic trajectory and volume changes of water droplets in real-time. Moreover, the micro-aperture, protected by the macro-frame, can withstand hundreds of impacts and abrasions and still maintain reliable separation efficiency. Under the encapsulation of micro-apertures, the macro-frame exhibits excellent corrosion resistance and can maintain stable superhydrophobicity even after long-term immersion in different harsh solutions. Due to its excellent durability, the SWCM can maintain a long service life in oil–water separation in complex environments. Therefore, the presented SWCM has great potential in the development of durable and efficient materials for emulsion separation. [ABSTRACT FROM AUTHOR]