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The near-dry electrical discharge machining processes have been conducted using air-mist or gas mist as a dielectric fluid to minimize the environmental impacts. In this article, near-dry electrical discharge machining (NDEDM) experiments have been performed to improve machining performance using an oxygen-mist dielectric fluid, a copper composite electrode, and Cu-Al-Be polycrystalline shape memory alloy (SMA) work materials. The copper composite electrode is made up of 12 wt% silicon carbide and 9 wt% graphite particles. The oxygen-mist pressure (Op), pulse on time (Ton), spark current (Ip), gap voltage (Gv), and flow rate of mixed water (Fr) were used as process parameters, and the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) were used as performance characteristics. The global optimal alternative solution has been predicted by the PROMETHEE-II (Preference Ranking Organization METhod for Enrichment Evaluations-II) optimization technique. The best combinations of process parameters have been used to examine the microstructure of composite tools and SMA-machined surfaces by scanning electron microscopy (SEM) analysis. The best global optimum settings (oP: 9 bar, Ip: 60 µs, Ip: 12 A, Gv: 40 V, and Fr: 12 ml/min) are predicted to attain optimum machining performance (MRR: 39.049 g/min, TWR: 1.586 g/min, and SR: 1.78 µm). The tool wear rate of the NDEDM process has been significantly reduced by the copper composite electrode due to increasing microhardness, wear resistance, and melting point. When compared to the pure copper electrode tool, the MRR of NDEDM is improved to 21.91%, while the TWR and SR are reduced to 46.66% and 35.02%, respectively.

[...] the tendency for the mist to deposit on the top of the ridge.

Bone grinding is an essential and vital procedure in most surgical operations. Currently, the insufficient cooling capacity of dry grinding, poor visibility of drip irrigation surgery area, and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding. A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling (U-NJMC) is innovatively proposed to solve the technical problem. It combines the advantages of ultrasonic vibration (UV) and nanoparticle jet mist cooling (NJMC). Notwithstanding, the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated. The grinding force, friction coefficient, specific grinding energy, and grinding temperature under dry, drip irrigation, UV, minimum quantity lubrication (MQL), NJMC, and U-NJMC micro-grinding were compared and analyzed. Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N, which were 75.1% and 82.9% less than those in dry grinding, respectively. The minimum friction coefficient and specific grinding energy were achieved using U-NJMC. Compared with dry, drip, UV, MQL, and NJMC grinding, the friction coefficient of U-NJMC was decreased by 31.3%, 17.0%, 19.0%, 9.8%, and 12.5%, respectively, and the specific grinding energy was decreased by 83.0%, 72.7%, 77.8%, 52.3%, and 64.7%, respectively. Compared with UV or NJMC alone, the grinding temperature of U-NJMC was decreased by 33.5% and 10.0%, respectively. These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone.

Background and Objectives: The incidence of pyogenic spondylodiscitis has been increasing due to the aging of the population. Although surgical treatment is performed for refractory pyogenic spondylodiscitis, surgical invasiveness should be considered. Recent minimally invasive spine stabilization (MISt) using percutaneous pedicle screw (PPS) can be a less invasive approach. The purpose of this study was to evaluate surgical results and clinical outcomes after MISt with PPS for pyogenic spondylodiscitis. Materials and Methods: Clinical data of patients who underwent MISt with PPS for pyogenic spondylitis were analyzed. Results: Twenty-three patients (18 male, 5 female, mean age 67.0 years) were retrospectively enrolled. The mean follow-up period was 15.9 months after surgery. The causative organism was identified in 16 cases (69.6%). A mean number of fixed vertebrae was 4.1, and the estimated blood loss was 145.0 mL. MISt with PPS was successfully performed in 19 of 23 patients (82.6%). Four cases (17.4%) required additional anterior debridement and autologous iliac bone graft placement. CRP levels had become negative at an average of 28.4 days after surgery. There was no major perioperative complication and no screw or rod breakages during follow-up. Conclusions: MISt with PPS would be a less invasive approach for pyogenic spondylodiscitis in elderly or immunocompromised patients.

Remote sensing target detection technology in cloud and mist scenes is of great significance for applications such as marine safety monitoring and airport traffic management. However, the degradation and loss of features caused by the obstruction of cloud and mist elements still pose a challenging problem for this technology. To enhance object detection performance in adverse weather conditions, we propose a novel target detection method named CM-YOLO that integrates background suppression and semantic context mining, which can achieve accurate detection of targets under different cloud and mist conditions. Specifically, a component-decoupling-based background suppression (CDBS) module is proposed, which extracts cloud and mist components based on characteristic priors and effectively enhances the contrast between the target and the environmental background through a background subtraction strategy. Moreover, a local-global semantic joint mining (LGSJM) module is utilized, which combines convolutional neural networks (CNNs) and hierarchical selective attention to comprehensively mine global and local semantics, achieving target feature enhancement. Finally, the experimental results on multiple public datasets indicate that the proposed method realizes state-of-the-art performance compared to six advanced detectors, with mAP, precision, and recall indicators reaching 85.5%, 89.4%, and 77.9%, respectively.

This paper includes initial research on the deployment of water purification systems that employ an evaporator-type heater and water trapper as the main components for purifying water, based on the fundamental principles of evaporative cooling air conditioning. In this experiment, the feed water is clean water that undergoes atomization through a mist nozzle with a diameter of 0.3, 0.4, 0,6 and 0.8 mm are employed interchangeably in the experiment. The feed water is accumulated within a receptacle and afterwards propelled through the use of a diaphragm pump, which may generate pressures of up to 5 bar. The experiment involved the acquisition of temperature data, which was recorded at a 2-second interval over a duration of 900 seconds. The efficacy of water purification through the utilization of an evaporator-type heater and water trap has been empirically demonstrated, resulting in the production of effectively captured water. Theoretically, the most favorable productivity can be achieved by employing a nozzle with a diameter of 0.6 mm. In the context of experimental practice, it has been observed that a nozzle possessing a diameter of 0.5 – 0.6 mm exhibits the greatest volumetric output of purified water when compared to alternative nozzle dimensions.

The self-ignition accident of pressurized hydrogen leakage is regarded as one of the big potential risks in its wide utilization. In this work, a detailed investigation into the suppression effect of water mist on the hydrogen self-ignition and flame propagation is performed. A parametric study of the effect of water concentration and droplet size on flame dynamic is conducted. The results show that the fine water mist effectively reduces the shock-heating temperature, significantly prolonging the ignition time and distance. The water droplets have a direct contact with the fast growing flame, which leads to more intense two-phase interaction that results in the decoupling of shock wave from the leading flame and a more pronounced bimodal flame structures. The droplet size is found to have small effect when the water concentration is low, and the mist with a medium size of 50 μm shows a better inhibitory performance.

The present work focuses on the experimental and numerical investigation of air-water mist jet impingement heat transfer from a heated flat plate. The heated flat plate is constructed from a 25μm Stainless steel-304 foil, and the temperature distribution on the plate is recorded with the help of Infrared Thermography. The detailed experimental parametric study is performed for a varied range of parameters such as plate heat flux (4000−16500 W/m 2 ), mist loading fraction (0−1.5%), Reynolds number of air-jet (4500−8800) and plate-to-nozzle distance (20−40). The temperature distribution over the heated flat plate is used to evaluate the effect of the above parameters on the local and average heat transfer coefficient and Nusselt number. A two-phase, stochastically dispersed mist droplets in air-jet is modeled based on Eulerian-Langragian approach for the numerical study. Heat transfer from the droplets and the liquid film formation over the heated surface and its evaporation is modelled in the numerical study. The present numerical results are found to be in good agreement with the experimental results. An increase in the heat transfer rate with an increase in the mist loading fraction and Reynolds number is reported. Also, the heat transfer rate decreases with an increase in the plate-to-nozzle distance. A maximum increment of 132% in the average Nusselt number is reported during both the experimental and numerical analysis, whereas 275% and 281% increment for the local Nusselt number at the stagnation point is reported during the experimental and numerical analysis as compared to the air jet impingement, respectively. Further, correlations are proposed for local and average increment in the Nusselt number in terms of Reynolds number, plate-to-nozzle distance, and mist loading fraction.

Lithium-ion batteries (LiBs) are a proven technology for energy storage systems, mobile electronics, power tools, aerospace, automotive and maritime applications. LiBs have attracted interest from academia and industry due to their high power and energy densities compared to other battery technologies. Despite the extensive usage of LiBs, there is a substantial fire risk associated with their use which is a concern, especially when utilised in electric vehicles, aeroplanes, and submarines. This review presents LiB hazards, techniques for mitigating risks, the suppression of LiB fires and identification of shortcomings for future improvement. Water is identified as an efficient cooling and suppressing agent and water mist is considered the most promising technique to extinguish LiB fires. In the initial stages, the present review covers some relevant information regarding the material constitution and configuration of the cell assemblies, and phenomenological evolution of the thermal runaway reactions, which in turn can potentially lead to flaming combustion of cells and battery assemblies. This is followed by short descriptions of various active fire control agents to suppress fires involving LiBs in general, and water as a superior extinguishing medium in particular. In the latter parts of the review, the phenomena associated with water mist suppression of LiB fires are comprehensively reviewed.

Fire accidents are unpredictable, especially oil fires, which often lead to serious losses because they cannot be extinguished quickly. Accidents are unavoidable, even though it is desirable to prevent them with solid preventative measures. There are two approaches to the study of fire. On the one hand, it is to study the intrinsic safety of hazardous substances; on the other hand, it is to study the energy efficiency of fire extinguishing substances. While the latter tries to investigate effective control conditions, the former aims to prevent the occurrence of fires. In reality, as the most commonly used fire extinguishing carrier, water is an effective weapon for different fires. Therefore, with the purpose of environmental protection and energy conservation, the fire extinguishing effect of the water mist system under pure water and low concentration of green additives is explored. The self-made polymer composite additives and NaCl salt were compared with pure water mist system. The findings show that under this low-pressure system, 1% polymer composite additives had the best extinction efficiency enhancement, pure water under medium and high pressure was more effective, and 1% NaCl salt additive negatively correlated with the extinction efficiency.