This study proposes the development of contamination measurement for industrial machines based on magnetic field method. A permanent magnet was used to generate the 0.17 T magnetic fields and Hall Effect sensor was ap...This study proposes the development of contamination measurement for industrial machines based on magnetic field method. A permanent magnet was used to generate the 0.17 T magnetic fields and Hall Effect sensor was applied to measure the contamination level of metal particles in industrial machine lubricant during operation time and to predict the replacement period if the lubricant condition does not meet the standard (NAS 1638). Contamination level of metal particles was directly related to the output voltage of Hall Effect sensor. When there was any movement of metal particles to the permanent magnet, the measured result was then transferred to a computer for analysis. This methodology could be applied to experiment the conditions of used lubricant for assessing the contamination and the metal particle remaining in the tank or inside the pipe of the machine as well as the conditions of car lubricant and other lubricants used in industrial processes.展开更多
Air pollution monitoring is one of the most important features in contamination risk management.This is because many of the compounds contained within air pollution present a serious risk both for the preservation of ...Air pollution monitoring is one of the most important features in contamination risk management.This is because many of the compounds contained within air pollution present a serious risk both for the preservation of open air cultural heritage and for human health.New particle formation is a major contributor to urban pollution,but how it occurs in cities is often puzzling.As more and more people enjoy an increased quality of life through outdoor activity,managing outdoor air quality is vital.This study presents the application of a low-cost system for monitoring the current level of road traffic passengers’exposure to particulate air contamination.The global rise in tourism also leads to apprehension about its probable destructive influence on various aspects of global preservation.One of the major risks encountered by tourists,stemming from modes of transport,are nanoparticles(NPs)(<100 nm)and ultra-fine particles(UFPs)(100-1000 nm)consisting of potentially hazardous elements(PHEs).This study examines Steen Castle,a medieval fortress located in Antwerp,Belgium.Significant NPs with PHEs,were found in the air sampled in this area.The self-made passive sampler(LSPS)described in this study,consisting of retainers specially designed for advanced microscopic analysis,is used for the first time as a simple way to characterize the surrounding atmospheric contamination caused by NPs and UFPs,without the need of other commonly employed more expensive particulate focused active samplers such as cascade impactors.This study aims to assess the result of the utilization of a low-cost,LSPS,to determine outdoor NPs and UFPs in a Belgian urban(Steen Castle)and rural area(Fort van Schoten).This work is the first to detail the usefulness of LSPS for the evaluation of Belgium’s outdoor air for NPs and UFPs,which contain PHEs.展开更多
Solid contamination existing as solid particles in power fluid transmission systems may lead to transmission performance reduction,system failures,and component damage.The hydraulic reservoir will deposit the contamin...Solid contamination existing as solid particles in power fluid transmission systems may lead to transmission performance reduction,system failures,and component damage.The hydraulic reservoir will deposit the contamination and store hydraulic fluid.To investigate its purification ability for solid contamination,experiments and simulations for the motion and deposition status of the typical hydraulic system particles are carried out to reveal the interaction of particles and fluid in hydraulic water reservoirs.The results show that the CFD-DEM coupling method could predict the accurate deposition position of iron particles and sand particles when ignoring the small-scale turbulence effect in the flow field.Besides,the particle motion traces and deposition patterns in the reservoir illustrate that the flow development on the bottom surface results in the particles turning,and particles tend to settle in the low flow energy position.The motion of particles is also linked to particles Stokes number,and the same-size sand particles are easily driven by the fluid.The contribution of this paper could provide a guide for predicting the particle motion and deposition pattern in the hydraulic reservoir.展开更多
The high-power laser beam in the final optics assembly of high-power laser facilities is often modulated by contamina- tion particles, which may cause local high light intensity, thereby increasing the filamentary dam...The high-power laser beam in the final optics assembly of high-power laser facilities is often modulated by contamina- tion particles, which may cause local high light intensity, thereby increasing the filamentary damage probability for optical components. To study the general design basis for a final optics assembly to decrease the risk of filamentary damage, different-sized contamination particles deposited on a component surface are simulated to modulate a 351-nm laser beam based on the optical transmission theory, and the corresponding simulation results are analyzed statistically in terms of the propagation characteristic and the light field intensity distribution of the modulated laser beam. The statistical results show that component thickness and distance between components can to some extent be optimized to reduce the appearance of local high light intensity, and the general design basis of component thickness and arrangement are given for different control levels of particle sizes. Moreover, the statistical results can also predict the laser beam quality approximately under the existing optics design and environmental cleanliness. The optimized design for final optics assembly based on environmental cleanliness level is useful to prolong the lifetime of optics and enhance the output power of high-power laser facilities.展开更多
文摘This study proposes the development of contamination measurement for industrial machines based on magnetic field method. A permanent magnet was used to generate the 0.17 T magnetic fields and Hall Effect sensor was applied to measure the contamination level of metal particles in industrial machine lubricant during operation time and to predict the replacement period if the lubricant condition does not meet the standard (NAS 1638). Contamination level of metal particles was directly related to the output voltage of Hall Effect sensor. When there was any movement of metal particles to the permanent magnet, the measured result was then transferred to a computer for analysis. This methodology could be applied to experiment the conditions of used lubricant for assessing the contamination and the metal particle remaining in the tank or inside the pipe of the machine as well as the conditions of car lubricant and other lubricants used in industrial processes.
基金funding received from the Brazilian National Council for Scientific and Technological Development(CNPq)the Administrative Department of Science,Technology,and Innovation of the Colombian Government(Colciencias)。
文摘Air pollution monitoring is one of the most important features in contamination risk management.This is because many of the compounds contained within air pollution present a serious risk both for the preservation of open air cultural heritage and for human health.New particle formation is a major contributor to urban pollution,but how it occurs in cities is often puzzling.As more and more people enjoy an increased quality of life through outdoor activity,managing outdoor air quality is vital.This study presents the application of a low-cost system for monitoring the current level of road traffic passengers’exposure to particulate air contamination.The global rise in tourism also leads to apprehension about its probable destructive influence on various aspects of global preservation.One of the major risks encountered by tourists,stemming from modes of transport,are nanoparticles(NPs)(<100 nm)and ultra-fine particles(UFPs)(100-1000 nm)consisting of potentially hazardous elements(PHEs).This study examines Steen Castle,a medieval fortress located in Antwerp,Belgium.Significant NPs with PHEs,were found in the air sampled in this area.The self-made passive sampler(LSPS)described in this study,consisting of retainers specially designed for advanced microscopic analysis,is used for the first time as a simple way to characterize the surrounding atmospheric contamination caused by NPs and UFPs,without the need of other commonly employed more expensive particulate focused active samplers such as cascade impactors.This study aims to assess the result of the utilization of a low-cost,LSPS,to determine outdoor NPs and UFPs in a Belgian urban(Steen Castle)and rural area(Fort van Schoten).This work is the first to detail the usefulness of LSPS for the evaluation of Belgium’s outdoor air for NPs and UFPs,which contain PHEs.
基金National Key Research and Development Program of China(Grant No.2018YFB2000703)National Natural Science Foundation of China(Grant No.51975507).
文摘Solid contamination existing as solid particles in power fluid transmission systems may lead to transmission performance reduction,system failures,and component damage.The hydraulic reservoir will deposit the contamination and store hydraulic fluid.To investigate its purification ability for solid contamination,experiments and simulations for the motion and deposition status of the typical hydraulic system particles are carried out to reveal the interaction of particles and fluid in hydraulic water reservoirs.The results show that the CFD-DEM coupling method could predict the accurate deposition position of iron particles and sand particles when ignoring the small-scale turbulence effect in the flow field.Besides,the particle motion traces and deposition patterns in the reservoir illustrate that the flow development on the bottom surface results in the particles turning,and particles tend to settle in the low flow energy position.The motion of particles is also linked to particles Stokes number,and the same-size sand particles are easily driven by the fluid.The contribution of this paper could provide a guide for predicting the particle motion and deposition pattern in the hydraulic reservoir.
基金supported by the National Natural Science Foundation of China(Grant No.60707019)
文摘The high-power laser beam in the final optics assembly of high-power laser facilities is often modulated by contamina- tion particles, which may cause local high light intensity, thereby increasing the filamentary damage probability for optical components. To study the general design basis for a final optics assembly to decrease the risk of filamentary damage, different-sized contamination particles deposited on a component surface are simulated to modulate a 351-nm laser beam based on the optical transmission theory, and the corresponding simulation results are analyzed statistically in terms of the propagation characteristic and the light field intensity distribution of the modulated laser beam. The statistical results show that component thickness and distance between components can to some extent be optimized to reduce the appearance of local high light intensity, and the general design basis of component thickness and arrangement are given for different control levels of particle sizes. Moreover, the statistical results can also predict the laser beam quality approximately under the existing optics design and environmental cleanliness. The optimized design for final optics assembly based on environmental cleanliness level is useful to prolong the lifetime of optics and enhance the output power of high-power laser facilities.
