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The abrasive flow precision machining technology was used to carry out numerical simulation and experimental research for the special-shaped deep holes. A large-eddy simulation method was used to numerically analyze the titanium alloy shaped hole parts, and related experimental studies were conducted to reveal the creation mechanism of the surface of the abrasive flow machining special-shaped curved surfaces. The study finds that: the effects of dynamic pressure, velocity, the pressure of abrasive particles on wall surfaces and the effects wall shear force on wall surfaces were revealed through numerical analysis of precision machining of abrasive flow. The vortex position distribution and the cause of the vortex as well as the interaction relationship between the vortex and the abrasive particles in the flow directional sections of the special-shaped section holes were obtained; After precision machining by abrasive flow, the surface roughness of special-shaped curved surfaces improves from Ra=7.136 µm, Rz=40.103 µm to Ra=1.822 µm, Rz=8.964 µm respectively. The protrusions and spheroidization on the inner surfaces of the shaped holes are removed, and the surface quality is significantly improved. The vortex greatly improves the surface quality of the special-shaped curved surfaces. [ABSTRACT FROM AUTHOR]

Background: Multiple sclerosis (MS) and Cerebral Small Vessel Disease (CSVD) exhibit some similarities in Magnetic resonance imaging (MRI), potentially leading to misdiagnosis and delaying effective treatment windows. It is unclear whether CSVD can be detected with Paramagnetic Rim Lesions (PRL), which is special in MS., Objective: We aimed to investigate whether PRL can serve as a neuroimaging marker for discriminating between MS and CSVD., Methods: In this retrospective study, 49 MS and 104 CSVD patients underwent 3.0 T Magnetic resonance imaging (MRI). Visual assessment of 37 MS patients and 89 CSVD patients with or without lacunes, cerebral microbleeds (CMBs), enlarged perivascular spaces (EPVS), white matter hyperintensity (WMH), central vein sign (CVS), and PRL. The distribution and number of PRL were then counted., Results: Our study found that PRL was detected in over half of the MS patients but was entirely absent in CSVD patients (78.38 vs. 0%, p  < 0.0001), and PRL showed high specificity with good sensitivity in discriminating between MS and CSVD (sensitivity: 78.38%, specificity: 100%, AUC: 0.96)., Conclusion: Paramagnetic Rim Lesions is a special imaging feature in MS, absent in CSVD. Detection of PRL can be very helpful in the clinical management of MS and CSVD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Zhu, Zhang, Li, Guo, Chen, Chen, Li, Wang, Chen and Fu.)

The object of this study was to estimate the sorption property of active silica derived from fly ash after separation of silica and aluminum. The specific surface area of active silica enlarged to 115 m(2)/g was compared with the original fly ash (4 m(2)/g). Field emission scanning electron microscopy displayed the active silica, which looked like a honeycomb or curly layer with many lamellae that formed many mesopores. The uptake kinetics indicated that the residual concentration of Pb(2+) in the aqueous solution decreased rapidly from the initial 1.25 mg/L to less than 10 μg/L within 45 min. The removal efficiency of Pb(2+) on active silica was pH dependent. The increase in pH value promoted Pb(2+) removal because the negative surface provided more electrostatic attraction sites. A stepwise non-linear isotherm was obtained because the lamellae of active silica provided a heterogeneous surface with various kinds of active sites. The maximum sorption amount of Pb on active silica was more than 90 mg/g, which was better than some pristine-activated carbon.