Daolong Yang

Introduction: Exhaust mufflers are widely utilized across a range of equipment and facilities that produce aerodynamic noise, providing notable benefits such as noise mitigation, environmental enhancement, and improved equipment stability. Nevertheless, they are also linked to certain challenges, including heightened back pressure, increased costs, and complexities in cleaning and maintenance. Methods: This article presents patents aimed at enhancing the noise reduction performance of exhaust mufflers, as well as academic literature on their performance optimization, providing valuable references for research on muffler design. Results: Integration of noise-reduction structures with sound-absorbing materials enables substantial enhancement of exhaust muffler performance. This approach not only strengthens noise attenuation efficacy and elevates exhaust efficiency but also improves environmental adaptability, thus providing a comprehensive solution for effective noise control. Discussion: A multi-stage impedance composite muffler design yields significant performance enhancements, which are attributed to sequential noise attenuation via multi-staging and expanded noise reduction bandwidth through the impedance composite configuration. Conclusion: This paper provides essential references for optimizing and improving exhaust mufflers, offering specific guidance for enhancing their filtration capabilities and noise reduction performance. It notably advances the efficiency of noise control in industrial applications.

High length‐to‐diameter ratio boring bars are prone to regenerative chatter during deep hole boring, which seriously restricts machining accuracy and stability. Passive damping boring bars, due to their reliable structure and strong engineering adaptability, have become the core technical direction for suppressing boring vibration. This paper systematically reviews the research progress of passive damping boring bars. Based on the vibration damping mechanism, the existing methods are classified into three major categories: energy dissipation type, dynamic vibration absorption type, and stiffness enhancement type. The structural features, applicable working conditions, and vibration damping performance of these methods are compared and analyzed. The research achievements and engineering performance of emerging technologies such as particle damping, constrained layer damping, nonlinear and adaptive dynamic vibration absorbers, as well as composite materials and lattice structures in wideband chatter suppression are mainly reviewed. Based on this, the common problems of the current passive damping boring bar in terms of frequency domain adaptability, parameter sensitivity, and multimechanism coupling modeling are summarized. The development direction of wideband adaptive, lightweight, and digital design is proposed, providing a systematic theoretical reference for the structural design and performance optimization of the passive damping boring bar.

Background: Coal storage and conveying are key aspects of the coal industry, including coal stacking management systems and conveying systems. The traditional method of coal storage will easily lead to coal’s spontaneous combustion, which decreases the safety and reliability of storage. Meanwhile, problems are waiting to be solved with current conveying technologies, such as low levels of conveying efficiency. Objective: To enhance the efficiency of coal conveying while improving safety and reducing environmental pollution, and promote the application of closed coal storage systems and pneumatic conveying technology. Method: The patents and research proposed by many scholars analyzed the problems in coal transportation. Adopting pneumatic conveying technology and utilizing a similar experimental bench, by controlling the angle of the suction feeder and the height from the bottom, getting the optimal suction angle and position via experiment, which improves the efficiency of coal pneumatic feeding and discharging. Results: A pneumatic feeding and discharging system and method are proposed for a coal storage silo with a high degree of integration and safety. Through similar experiments, it is concluded that the conveying efficiency is highest when the suction feeder is 30 mm high from the bottom, and the angle of the suction feeder is 45°. This provides theoretical support for the specific application of the device. Conclusion: By analyzing patents and researching similar experiments, the proposed closed storage system for coal can improve coal conveying efficiency, reduce environmental pollution caused by coal particles during conveying, and decrease the possibility of spontaneous combustion and explosion of coal dust. The system is highly automated, easy to operate, and widely applicable.

Since the discovery of the “lotus effect,” the superhydrophobic structure of the research is more and more profound. When the droplets fall on the surface, it will not occur as a wetting phenomenon. Making full use of this feature will achieve the self-cleaning effect of the object surface. In the dust filtration problem, it is possible to spray superhydrophobic materials on the surface of the equipment using superhydrophobic self-cleaning characteristics to change the filtering method and to improve the self-cleaning efficiency. This paper describes the methods of preparing superhydrophobic materials, self-cleaning methods, and the application of superhydrophobic materials in the field of self-cleaning. Based on the summary of patents and papers, this paper focuses on the filtration and self-cleaning effect of superhydrophobic materials on dust particles in humid environments. With a simple structure, high filtration efficiency, and long service life, the super sparse/hydrophilic hybrid mesh can work continuously without manual operation. It can effectively filter dust particles and improve air quality in humid environments. Coal powder condensation experiments in this paper proved that the application of superhydrophobic materials in the field of self-cleaning yielded significant results. When superhydrophobic materials are sprayed on copper-based filters, the hydrophilic line mixes with the hydrophobic region, greatly improving the self-cleaning efficiency.

The shortcomings of conventional human instrument inspection, such as its low efficiency, high risk, and data latency, have been made clear by the rapidly growing trend of industrial automation and intelligentization. An essential instrument for unmanned operation and maintenance is the instrument and meter inspection robot, which combines multimodal sensors, autonomous navigation, and intelligent identification technologies. The technical foundation and current state of application for instrument and meter inspection robots are systematically reviewed in this study. We critically examine the advancements in instrument recognition research and present the sensors, autonomous navigation algorithms, and identification technologies utilized in instrument and meter inspection robots. We tested a prototype of a standard wheeled inspection robot in the instrument inspection of a cement plant and reported the test findings to further examine the viability of inspection robots. Furthermore, we evaluate the challenges in the development of instrument and meter inspection robots and propose potential avenues for future research.

Coal is mostly stored in coal bunkers. As the amount of coal in the bunker increases, the concentration of coal dust inside the bunker also increases, making it susceptible to accidents such as fires and explosions. Additionally, the leakage of coal dust particles can cause significant environmental pollution in the surrounding area, leading to resource wastage. To improve energy efficiency, reduce material transport dust concentration, and protect the surrounding environment, the efficient, energy-saving, and environmentally friendly characteristics of pneumatic conveying systems are utilized. This is achieved through the use of anti-dust telescopic pipeline equipment (DTPE), which effectively prevents external dust particles from entering the telescopic pipeline, thus reducing mechanical wear. In environments with high coal dust concentration, a coal particle pneumatic conveying storage system based on DTPE is used to extend the service life of pneumatic conveying pipelines and effectively reduce the coal dust concentration within the storage bin. This study reviews the patents and research achievements of scholars in the field of pneumatic conveying and focuses on the anti-dust telescopic pipeline equipment (DTPE) and the coal particle pneumatic conveying storage system based on DTPE. Experiments using pneumatic conveying, screw conveyors, and belt conveyors are conducted to compare conveying time and efficiency. Dust reduction experiments are carried out in the coal bunker to verify the dust reduction effect of the coal particle pneumatic conveying storage system based on DTPE. The anti-dust telescopic pipeline equipment (DTPE) features a telescopic shell to protect the telescopic pipeline, effectively reducing mechanical wear caused by coal particles entering the gaps in the pipeline during pneumatic conveying. The coal particle pneumatic conveying storage system based on DTPE includes a cyclone dust removal system and a dynamic monitoring system, which monitors the temperature inside the bin and reduces the coal dust concentration, thereby minimizing the occurrence of safety accidents. Through experimental verification, the coal particle pneumatic conveying storage system based on DTPE is found to be suitable for environments with high coal dust concentrations. The anti-dust telescopic pipeline equipment (DTPE) and the coal particle pneumatic conveying storage system based on DTPE achieve the automated feeding, dust removal, return, and discharge of coal particles. They offer advantages such as high system automation, minimal environmental pollution, and high coal transport rates, providing design references for the pneumatic conveying of coal and other ore particle materials.