This paper introduces the method of coal dust treatment in crushing station and the present situation of dust removal system in typical open-pit coal mine crushing station in China,and expounds the research idea of de...This paper introduces the method of coal dust treatment in crushing station and the present situation of dust removal system in typical open-pit coal mine crushing station in China,and expounds the research idea of determining comprehensive dust removal(suppression)system in crushing station inspired by the working principle of"range hood".Based on the design example and link optimization of the crush-ing station of open-pit coal mine I of Thar coalfield,this paper finally draws some conclusions on the key technologies of dust removal(suppression)system of open-pit coal mine crushing station.This study has certain reference value for the technical innovation of dust removal(suppression)system in crushing station,the realization of green mining in"crushing link",and the reduction and avoidance of ecological environment pollution in mining area.展开更多
The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the...The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.展开更多
Dust removal from pyrolytic vapors at high temperatures is an obstacle to the industrialization of the coal pyrolysis process.In this work,a granular bed with expanded perlites as filtration media was designed and int...Dust removal from pyrolytic vapors at high temperatures is an obstacle to the industrialization of the coal pyrolysis process.In this work,a granular bed with expanded perlites as filtration media was designed and integrated into a 10 t·d^(–1)coal pyrolysis facility.The testing results showed that around 97.56%dust collection efficiency was achieved.As a result,dust content in tar was significantly lowered.The pressure drop of the granular bed maintained in the range of 356 Pa to 489 Pa.The dust size in the effluent after filtration exhibited a bimodal distribution,which was attributed to the heterogeneity of the dust components.The effects of filtration bed on pyrolytic product yields were also discussed.A modified filtration model based on the macroscopic phenomenological theory was proposed to describe the performance of the granular bed.The computation results were well agreed with the experimental data.展开更多
Ore production is usually affected by multiple influencing inputs at open-pit mines.Nevertheless,the complex nonlinear relationships between these inputs and ore production remain unclear.This becomes even more challe...Ore production is usually affected by multiple influencing inputs at open-pit mines.Nevertheless,the complex nonlinear relationships between these inputs and ore production remain unclear.This becomes even more challenging when training data(e.g.truck haulage information and weather conditions)are massive.In machine learning(ML)algorithms,deep neural network(DNN)is a superior method for processing nonlinear and massive data by adjusting the amount of neurons and hidden layers.This study adopted DNN to forecast ore production using truck haulage information and weather conditions at open-pit mines as training data.Before the prediction models were built,principal component analysis(PCA)was employed to reduce the data dimensionality and eliminate the multicollinearity among highly correlated input variables.To verify the superiority of DNN,three ANNs containing only one hidden layer and six traditional ML models were established as benchmark models.The DNN model with multiple hidden layers performed better than the ANN models with a single hidden layer.The DNN model outperformed the extensively applied benchmark models in predicting ore production.This can provide engineers and researchers with an accurate method to forecast ore production,which helps make sound budgetary decisions and mine planning at open-pit mines.展开更多
Polycyclic aromatic hydrocarbons(PAHs),PANHs,and peptoids dust spectral calculations from the interstellar medium(ISM)are important for dust observations and theory.Our goal is to calculate the radiation spectrum of s...Polycyclic aromatic hydrocarbons(PAHs),PANHs,and peptoids dust spectral calculations from the interstellar medium(ISM)are important for dust observations and theory.Our goal is to calculate the radiation spectrum of spherical PAHs dust clusters in a vacuum containing ionized and applied in the presence of an electric field.We propose a new simple computational model to calculate the size of three-dimensional spherical dust clusters formed by different initial dust structures.By the Vienna Ab-initio Simulation Package code,the density functional theory with the generalized approximation was used to calculate the electron density gradient and obtain the radiation spectrum of dust.When the radius of spherical dust clusters is~[0.009-0.042]μm,the dust radiation spectrum agrees well with the Z=0.02 mMMP stellar spectra,and the PAHs radiation spectrum of NGC 4676 at wavelengths of(0-5]μm and(5-10]μm,respectively.In the ionized state,the N-PAH,C_(10)H_(9)N,2(C_(4)H_(4))^(1+),and peptoids 4(CHON),(C_(8)H_(10)N_(2)O_(5))^(1+)dust clusters at 3.3μm,while the 2(C_(22)H_(21)N_(3)O_(2))^(1+),4(CHON)dust clusters at 5.2μm have obvious peaks.There is a characteristic of part of PAHs and peptoids clusters radiation at the nearinfrared wavelength of 2μm.However,especially after applying an electric field to the dust,the emission spectrum of the dust increases significantly in the radiation wavelength range[3-10]μm.Consequently,the dust clusters of PAHs,PANHs,and peptoids of the radius size~[0.009-0.042]μm are likely to exist in the ISM.展开更多
Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact...Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact of dust accumulation, these regions offer optimal solar radiation and minimal cloud cover, making them ideal candidates for widespread PV cell deployment. Various surface cleaning methods exist, each employing distinct approaches. Choosing an appropriate cleaning method requires a comprehensive understanding of the mechanisms involved in both dust deposition on module surfaces and dust adhesion to PV cell surfaces. The mechanisms governing dust deposition and adhesion are complex and multifaceted, influenced by factors such as the nature and properties of the dust particles, environmental climatic conditions, characteristics of protective coatings, and the specific location of the PV installation. These factors exhibit regional variations, necessitating the implementation of diverse cleaning approaches tailored to the unique conditions of each location. The first part of this article explores the factors influencing dust deposition on PV cell surfaces, delving into the intricate interplay of environmental variables and particle characteristics. Subsequently, the second part addresses various cleaning methods, offering an analysis of their respective advantages and disadvantages. By comprehensively examining the factors influencing dust accumulation and evaluating the effectiveness of different cleaning strategies, this article aims to contribute valuable insights to the ongoing efforts to optimize the performance and longevity of photovoltaic systems in diverse geographical contexts.展开更多
Saharan dust represents more than 50%of the total desert dust emitted around the globe and its radiative effect significantly affects the atmospheric circulation at a continental scale.Previous studies on dust vertica...Saharan dust represents more than 50%of the total desert dust emitted around the globe and its radiative effect significantly affects the atmospheric circulation at a continental scale.Previous studies on dust vertical distribution and the Saharan Air Layer(SAL)showed some shortcomings that could be attributed to imperfect representation of the effects of deep convection and scavenging.The authors investigate here the role of deep convective transport and scavenging on the vertical distribution of mineral dust over Western Africa.Using multi-year(2006-2010)simulations performed with the variable-resolution(zoomed)version of the LMDZ climate model.Simulations are compared with aerosol amounts recorded by the Aerosol Robotic Network(AERONET)and with vertical profiles of the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP)measurements.LMDZ allows a thorough examination of the respective roles of deep convective transport,convective and stratiform scavenging,boundary layer transport,and advection processes on the vertical mineral dust distribution over Western Africa.The comparison of simulated dust Aerosol Optical Depth(AOD)and distribution with measurements suggest that scavenging in deep convection and subsequent re-evaporation of dusty rainfall in the lower troposphere are critical processes for explaining the vertical distribution of desert dust.These processes play a key role in maintaining a well-defined dust layer with a sharp transition at the top of the SAL and in establishing the seasonal cycle of dust distribution.This vertical distribution is further reshaped offshore in the Inter-Tropical Convergence Zone(ITCZ)over the Atlantic Ocean by marine boundary layer turbulent and convective transport and wet deposition at the surface.展开更多
The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dyn...The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dynamics simulations were employed to study the impact of three types of surfactants on the surface adsorption properties and wettability of highly hydrophobic bituminous coal.The results show that the surface of highly hydrophobic bituminous coal is compact,rich in inorganic minerals,and poorly wettable and that coal molecules are dominated by hydrophobic functional groups of aromatic rings and aliphatic structures.The wetting performance of surfactants as the intermediate carrier to connect coal and water molecules is largely determined by the interaction force between surfactants and coal(Fs-c)and the interaction force between surfactants and water(Fs-w),which effectively improve the wettability of modified coal dust via modifying its surface electrical properties and surface energy.A new type of wetting agent with a dust removal rate of 89%has been developed through discovery of a compound wetting agent solution with optimal wetting and settling performance.This paper provides theoretical and technical support for removing highly hydrophobic bituminous coal dust in underground mining.展开更多
Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend...Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend on the nature and density of dust.The nature of dust was studied by means of scanning electron microscopy and energy dispersive x-ray spectroscopy.It was found that the granulometry of dust particles depends on the study area.For a dust density of around 20 g/m^(2),the maximum power Pmax of the solar panel decreases drastically from 30 to 20 W for the(HP)site,and no more than 14 W for the(AD)site.The diversity of the behavior of the soiled panel was explained in terms of the size of the particles collected from each area.The transmission of light across the front glass of the PV panel is more affected when the sizes of particles are small.展开更多
The red imported fire ant,Solenopsis invicta Buren,poses a significant threat to biodiversity,agriculture,and public health in its introduced ranges.While chemicals such as toxic baits and dust are the main methods fo...The red imported fire ant,Solenopsis invicta Buren,poses a significant threat to biodiversity,agriculture,and public health in its introduced ranges.While chemicals such as toxic baits and dust are the main methods for S.invicta control,toxic baits are slow,requiring approximately one or two weeks,but dust can eliminate the colony of fire ants rapidly in just three to five days.To explore more active ingredients for fire ant control using dusts,the toxicity of bifenthrin and dimefluthrin,the horizontal transfer of bifenthrin and dimefluthrin dust and their efficacy in the field were tested.The results showed that the LD50(lethal dose) values of bifenthrin and dimefluthrin were 3.40 and 1.57 ng/ant,respectively.The KT50(median knockdown time) and KT95(95%knockdown time) values of a 20μg mL^(–1)bifenthrin dose were 7.179and 16.611 min,respectively.The KT50and KT95of a 5μg mL^(–1)dimefluthrin dose were 1.538 and 2.825 min,respectively.The horizontal transfers of bifenthrin and dimefluthrin among workers were effective.The mortality of recipients (secondary mortality) and secondary recipients (tertiary mortality) were both over 80%at 48 h after 0.25,0.50 and 1.00%bifenthrin dust treatments.The secondary mortality of recipients was over 99%at 48 h after 0.25,0.50 and 1.00% dimefluthrin dust treatments,but the tertiary mortality was below 20%.The field trial results showed that both bifenthrin and dimefluthrin exhibited excellent fire ant control effects,and the comprehensive control effects of 1.00%bifenthrin and dimefluthrin dusts at 14 d post-treatment were 95.87 and 85.70%,respectively.展开更多
Coal is the major source of power in India and world over.Coal mining is an essential industry which has a major role in the economic development of the country.Most major mining activities contribute directly or indi...Coal is the major source of power in India and world over.Coal mining is an essential industry which has a major role in the economic development of the country.Most major mining activities contribute directly or indirectly to air pollution.Coal dust is a major air pollutant which affects the personal working in the mines and also people residing in villages near the mines.Air pollution due to coal particulates can affect human health and cause damages to the environment.Hence effective pollution control mechanisms are needed to keep the pollution levels within permissible levels.The easiest and most common method employed for dust suppression worldwide is sprinkling of water.In majority of mines,water sprinklers are operated manually and can lead to wastage of water due to over sprinkling.It can also prove to be ineffective in dust suppression if sprinkling is not done properly.The paper proposes a system which can be deployed to automate the dust suppressions sprinklers.The system will monitor the concentration of PM_(10) and PM_(2.5) in the air and initiate sprinkling operation when the particulate matter content exceeds preconfigured limits.展开更多
Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and property.Against the backdrop of climate ...Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and property.Against the backdrop of climate change,Mongolia’s contribution to China’s dust cannot be ignored in recent years.In this study,we used the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),along with dynamic dust sources and the HYSPLIT model,to analyze the contributions of different dust sources to dust concentrations in northern China in March and April 2023.The results show that the frequency of dust storms in 2023 was the highest observed in the past decade.Mongolia and the Taklimakan Desert were identified as two main dust sources contributing to northern China.Specifically,Mongolia contributed more than 42%of dust,while the Taklimakan Desert accounted for 26%.A cold high-pressure center,a cold front,and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China,where they affected most parts of the region.Moreover,two machine learning methods[the XGBoost algorithm and the Synthetic Minority Oversampling Technique(SMOTE)]were used to forecast the dust storms in March 2023,based on ground observations and WRF-Chem simulations over East Asia.XGBoost-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023,with a mean absolute error of 33.8μg m−3 and RMSE of 54.2μg m−3.展开更多
Single-fuid nozzles and dual-fuid nozzles are the two typical jet crushing methods used in spray dust reduction. To distinguish the atomization mechanism of single-fuid and dual-fuid nozzles and improve dust control e...Single-fuid nozzles and dual-fuid nozzles are the two typical jet crushing methods used in spray dust reduction. To distinguish the atomization mechanism of single-fuid and dual-fuid nozzles and improve dust control efciency at the coal mining faces, the atomization characteristics and dust reduction performance of the two nozzles were quantitatively compared. Results of experiments show that, as water supply pressure increased, the atomization angle of the swirl pressure nozzle reaches a maximum of 62° at 6 MPa and then decreases, but its droplet size shows an opposite trend with a minimum of 41.7 μm. The water supply pressure helps to improve the droplet size and the atomization angle of the internal mixing air–liquid nozzle, while the air supply pressure has a suppressive efect for them. When the water supply pressure is 0.2 MPa and the air supply pressure reaches 0.4 MPa, the nozzle obtains the smallest droplet size which is 10% smaller than the swirl pressure nozzle. Combined with the dust reduction experimental results, when the water consumption at the working surface is not limited, using the swirl pressure nozzle will achieve a better dust reduction efect. However, the internal mixing air–liquid nozzle can achieve better and more economical dust reduction performance in working environments where water consumption is limited.展开更多
Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avo...Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avoiding hydrogen explosion risks,we try to use a combination of chitosan(CS)and sodium phosphate(SP)to inhibit the hydrogen evolution reaction between magnesium alloy waste dust and water.The hydrogen evolution curves and chemical kinetics modeling for ten different mixing ratios demonstrate that 0.4wt%CS+0.1wt%SP yields the best inhibition efficiency with hydrogen generation rate of almost zero.SEM and EDS analyses indicate that this composite inhibitor can create a uniform,smooth,tight protective film over the surface of the alloy dust particles.FTIR and XRD analysis of the chemical composition of the surface film show that this protective film contains CS and SP chemically adsorbed on the surface of ZK60 but no detectable Mg(OH)_(2),suggesting that magnesium-water reaction was totally blocked.Our new method offers a thorough solution to hydrogen explosion by inhibiting the hydrogen generation of magnesium alloy waste dust in a wet dust removal system.展开更多
The cyclone dust collector is an important subsystem of straw crushers used in agriculture.In the present study,a new type of dust collector with involute morphology is proposed to obtain better dust removal efficienc...The cyclone dust collector is an important subsystem of straw crushers used in agriculture.In the present study,a new type of dust collector with involute morphology is proposed to obtain better dust removal efficiency with respect to that of classical tangential and spiral dust collectors.A discrete phase model(DPM)method is used in synergy with a turbulence model,and the SIMPLE algorithm to simulate the flow field inside the dust collector and the related particle dynamics.It is shown that the internal flow field features a primary swirl,a secondary swirl and blockage effects.Moreover,for the involute dust collector,the tangential velocity in the initial stage and the pressure in the high-pressure area are larger than those obtained for the classical types.The dust removal efficiency is 37.11%,25.3%,and 16.37%for the involute type dust collector,the tangential type and the spiral type,respectively.展开更多
In the ELMy H-mode experiment,naturally occurring dust originating at the high-field side is clearly observed using the high-speed vacuum ultraviolet imaging system developed on the Experimental Advanced Superconducti...In the ELMy H-mode experiment,naturally occurring dust originating at the high-field side is clearly observed using the high-speed vacuum ultraviolet imaging system developed on the Experimental Advanced Superconducting Tokamak(EAST).The main ablation cloud shape is similar to the classical shape observed in pellet fueling experiments.However,during the dust penetration,an erupted secondary cloudlet with a bent‘cigar’shape is observed and moves upwards along the direction perpendicular to the magnetic field line,which is different to the obviation in the pellet fueling experiments.This may be due to the ion diamagnetic drift effect.The velocities of the secondary cloudlet are estimated to be 50–80 m s^(-1).In addition,a significant degradation of the plasma confinement is observed during the dust penetration.展开更多
A comprehensive evaluation method is proposed to analyze dust pollution generated in the production process of mines.The method employs an optimized image-processing and deep learning framework to characterize the gra...A comprehensive evaluation method is proposed to analyze dust pollution generated in the production process of mines.The method employs an optimized image-processing and deep learning framework to characterize the gray and fractal features in dust images.The research reveals both linear and logarithmic correlations between the gray features,fractal dimension,and dust mass,while employing Chauvenel criteria and arithmetic averaging to minimize data discreteness.An integrated hazardous index is developed,including a logarithmic correlation between the index and dust mass,and a four-category dataset is subsequently prepared for the deep learning framework.Based on the range of the hazardous index,the dust images are divided into four categories.Subsequently,a dust risk classifcation system is established using the deep learning model,which exhibits a high degree of performance after the training process.Notably,the model achieves a testing accuracy of 95.3%,indicating its efectiveness in classifying diferent levels of dust pollution,and the precision,recall,and F1-score of the system confrm its reliability in analyzing dust pollution.Overall,the proposed method provides a reliable and efcient way to monitor and analyze dust pollution in mines.展开更多
The key for dust control of coal mine is to clarify the dust concentration distribution and sedimentation in different areas. Both similarity experiment and numerical simulation method have certain restrictions and ar...The key for dust control of coal mine is to clarify the dust concentration distribution and sedimentation in different areas. Both similarity experiment and numerical simulation method have certain restrictions and are quite different from the actual situation on site. In order to study the dust sedimentation regularity of coal mine in large mining height, “filter membrane method” is adopted in this paper, i.e., to dry and weigh the filter membrane before and after sampling, collect the dust of respirable zone on mining face and calculate the dust concentration based on a main airway of 100 m. The result shows that: A large amount of dust will be produced during coal mining, wherein the maximum dust concentration from 6 m upstream to 100 m downstream of coal cutter is 121 mg/m3</sup>, while the minimum dust concentration is 61 mg/m3</sup>;The dust concentration in return airway is reduced with the distance increases, while the dust concentration at the entrance is 91 mg/m3</sup>;A large amount of dust may fall from roof during section advancing and improves the dust concentration of hydraulic support in walking area obviously;The dust granularity of mining face and return airway is 0 - 100 μm, but the amount of respirable dust is higher than 80%, the larger the dust particle size, the higher the dust concentration. Besides, dust in small particle size can be suspended in air flow for longer, but that in large particle size may subside under the action of gravity;To reduce dust exposure, the mining position shall be located in the windward direction of advancing or coal cutter. This research can provide guidance for taking dust prevention measures of working face in large mining height.展开更多
As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectrosco...As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectroscopy(IFS)with a resolution of 1–2 kpc for104galaxies in the local universe during its six-year operation from July 2014 through August 2020.It is crucial to reliably measure the physical properties of the different components in each spectrum before one can use the data for any scientific study.In the past years we have made lots of efforts to develop a novel technique of full spectral fitting,which estimates a model-independent dust attenuation curve from each spectrum,thus allowing us to break the degeneracy between dust attenuation and stellar population properties when fitting the spectrum with stellar population synthesis models.We have applied our technique to the final data release of Ma NGA,and obtained measurements of stellar population properties and emission line parameters,as well as the kinematics and dust attenuation of both stellar and ionized gas components.In this paper we describe our technique and the content and format of our data products.The whole dataset is publicly available in Science Data Bank with the link https://doi.org/10.57760/sciencedb.j00113.00088.展开更多
文摘This paper introduces the method of coal dust treatment in crushing station and the present situation of dust removal system in typical open-pit coal mine crushing station in China,and expounds the research idea of determining comprehensive dust removal(suppression)system in crushing station inspired by the working principle of"range hood".Based on the design example and link optimization of the crush-ing station of open-pit coal mine I of Thar coalfield,this paper finally draws some conclusions on the key technologies of dust removal(suppression)system of open-pit coal mine crushing station.This study has certain reference value for the technical innovation of dust removal(suppression)system in crushing station,the realization of green mining in"crushing link",and the reduction and avoidance of ecological environment pollution in mining area.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272001,11972046)the Outstanding Youth Project of Natural Science Foundation of Anhui Province(Grant No.2108085Y02)the Major Project of Anhui University Natural Science Foundation(Grant No.KJ2020ZD30)。
文摘The flame propagation processes of MgH_(2)dust clouds with four different particle sizes were recorded by a high-speed camera.The dynamic flame temperature distributions of MgH_(2)dust clouds were reconstructed by the two-color pyrometer technique,and the chemical composition of solid combustion residues were analyzed.The experimental results showed that the average flame propagation velocities of 23μm,40μm,60μm and 103μm MgH_(2)dust clouds in the stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,respectively.The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity,and their flame temperature distributions were more even and the temperature gradients were smaller.The flame structures of MgH_(2)dust clouds were significantly affected by the particle sinking velocity,and the combustion processes were accompanied by micro-explosion of particles.The falling velocities of 23μm and 40μm MgH_(2)particles were 2.24 cm/s and 6.71 cm/s,respectively.While the falling velocities of 60μm and 103μm MgH_(2)particles were as high as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular shape of the flame.Furthermore,the dehydrogenation reaction had a significant effect on the combustion performance of MgH_(2)dust.The combustion of H_(2)enhanced the ignition and combustion characteristics of MgH_(2)dust,resulting in a much higher explosion power than the pure Mg dust.The micro-structure characteristics and combustion residues composition analysis of MgH_(2)dust indicated that the combustion control mechanism of MgH_(2)dust flame was mainly the heterogeneous reaction,which was affected by the dehydrogenation reaction.
基金financial support from the National Key Research and Development Program of China(2018YFB0605003).
文摘Dust removal from pyrolytic vapors at high temperatures is an obstacle to the industrialization of the coal pyrolysis process.In this work,a granular bed with expanded perlites as filtration media was designed and integrated into a 10 t·d^(–1)coal pyrolysis facility.The testing results showed that around 97.56%dust collection efficiency was achieved.As a result,dust content in tar was significantly lowered.The pressure drop of the granular bed maintained in the range of 356 Pa to 489 Pa.The dust size in the effluent after filtration exhibited a bimodal distribution,which was attributed to the heterogeneity of the dust components.The effects of filtration bed on pyrolytic product yields were also discussed.A modified filtration model based on the macroscopic phenomenological theory was proposed to describe the performance of the granular bed.The computation results were well agreed with the experimental data.
基金This work was supported by the Pilot Seed Grant(Grant No.RES0049944)the Collaborative Research Project(Grant No.RES0043251)from the University of Alberta.
文摘Ore production is usually affected by multiple influencing inputs at open-pit mines.Nevertheless,the complex nonlinear relationships between these inputs and ore production remain unclear.This becomes even more challenging when training data(e.g.truck haulage information and weather conditions)are massive.In machine learning(ML)algorithms,deep neural network(DNN)is a superior method for processing nonlinear and massive data by adjusting the amount of neurons and hidden layers.This study adopted DNN to forecast ore production using truck haulage information and weather conditions at open-pit mines as training data.Before the prediction models were built,principal component analysis(PCA)was employed to reduce the data dimensionality and eliminate the multicollinearity among highly correlated input variables.To verify the superiority of DNN,three ANNs containing only one hidden layer and six traditional ML models were established as benchmark models.The DNN model with multiple hidden layers performed better than the ANN models with a single hidden layer.The DNN model outperformed the extensively applied benchmark models in predicting ore production.This can provide engineers and researchers with an accurate method to forecast ore production,which helps make sound budgetary decisions and mine planning at open-pit mines.
基金the Independent Innovation Project for Postgraduates of Central South University(No.160171008)the National Natural Science Foundation of China(project No.U2031204)the project of Xinjiang(No.2021D01C075)。
文摘Polycyclic aromatic hydrocarbons(PAHs),PANHs,and peptoids dust spectral calculations from the interstellar medium(ISM)are important for dust observations and theory.Our goal is to calculate the radiation spectrum of spherical PAHs dust clusters in a vacuum containing ionized and applied in the presence of an electric field.We propose a new simple computational model to calculate the size of three-dimensional spherical dust clusters formed by different initial dust structures.By the Vienna Ab-initio Simulation Package code,the density functional theory with the generalized approximation was used to calculate the electron density gradient and obtain the radiation spectrum of dust.When the radius of spherical dust clusters is~[0.009-0.042]μm,the dust radiation spectrum agrees well with the Z=0.02 mMMP stellar spectra,and the PAHs radiation spectrum of NGC 4676 at wavelengths of(0-5]μm and(5-10]μm,respectively.In the ionized state,the N-PAH,C_(10)H_(9)N,2(C_(4)H_(4))^(1+),and peptoids 4(CHON),(C_(8)H_(10)N_(2)O_(5))^(1+)dust clusters at 3.3μm,while the 2(C_(22)H_(21)N_(3)O_(2))^(1+),4(CHON)dust clusters at 5.2μm have obvious peaks.There is a characteristic of part of PAHs and peptoids clusters radiation at the nearinfrared wavelength of 2μm.However,especially after applying an electric field to the dust,the emission spectrum of the dust increases significantly in the radiation wavelength range[3-10]μm.Consequently,the dust clusters of PAHs,PANHs,and peptoids of the radius size~[0.009-0.042]μm are likely to exist in the ISM.
文摘Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact of dust accumulation, these regions offer optimal solar radiation and minimal cloud cover, making them ideal candidates for widespread PV cell deployment. Various surface cleaning methods exist, each employing distinct approaches. Choosing an appropriate cleaning method requires a comprehensive understanding of the mechanisms involved in both dust deposition on module surfaces and dust adhesion to PV cell surfaces. The mechanisms governing dust deposition and adhesion are complex and multifaceted, influenced by factors such as the nature and properties of the dust particles, environmental climatic conditions, characteristics of protective coatings, and the specific location of the PV installation. These factors exhibit regional variations, necessitating the implementation of diverse cleaning approaches tailored to the unique conditions of each location. The first part of this article explores the factors influencing dust deposition on PV cell surfaces, delving into the intricate interplay of environmental variables and particle characteristics. Subsequently, the second part addresses various cleaning methods, offering an analysis of their respective advantages and disadvantages. By comprehensively examining the factors influencing dust accumulation and evaluating the effectiveness of different cleaning strategies, this article aims to contribute valuable insights to the ongoing efforts to optimize the performance and longevity of photovoltaic systems in diverse geographical contexts.
基金The authors wish to thank the Ecosystem Approach to the management of fisheries and the marine environment in the West African Waters(AWA)project.They also acknowledge support from the international joint laboratory ECLAIRS.The Laboratoire de Météorologie Dynamique(LMD)and the Global Challenges Research Fund(GCRF)African Science for Weather Information and Techniques(SWIFT)Programme.NASA,CNES,and ICARE are acknowledged for providing access to CALIOP and Sun photometer AERONET data.
文摘Saharan dust represents more than 50%of the total desert dust emitted around the globe and its radiative effect significantly affects the atmospheric circulation at a continental scale.Previous studies on dust vertical distribution and the Saharan Air Layer(SAL)showed some shortcomings that could be attributed to imperfect representation of the effects of deep convection and scavenging.The authors investigate here the role of deep convective transport and scavenging on the vertical distribution of mineral dust over Western Africa.Using multi-year(2006-2010)simulations performed with the variable-resolution(zoomed)version of the LMDZ climate model.Simulations are compared with aerosol amounts recorded by the Aerosol Robotic Network(AERONET)and with vertical profiles of the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP)measurements.LMDZ allows a thorough examination of the respective roles of deep convective transport,convective and stratiform scavenging,boundary layer transport,and advection processes on the vertical mineral dust distribution over Western Africa.The comparison of simulated dust Aerosol Optical Depth(AOD)and distribution with measurements suggest that scavenging in deep convection and subsequent re-evaporation of dusty rainfall in the lower troposphere are critical processes for explaining the vertical distribution of desert dust.These processes play a key role in maintaining a well-defined dust layer with a sharp transition at the top of the SAL and in establishing the seasonal cycle of dust distribution.This vertical distribution is further reshaped offshore in the Inter-Tropical Convergence Zone(ITCZ)over the Atlantic Ocean by marine boundary layer turbulent and convective transport and wet deposition at the surface.
文摘The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dynamics simulations were employed to study the impact of three types of surfactants on the surface adsorption properties and wettability of highly hydrophobic bituminous coal.The results show that the surface of highly hydrophobic bituminous coal is compact,rich in inorganic minerals,and poorly wettable and that coal molecules are dominated by hydrophobic functional groups of aromatic rings and aliphatic structures.The wetting performance of surfactants as the intermediate carrier to connect coal and water molecules is largely determined by the interaction force between surfactants and coal(Fs-c)and the interaction force between surfactants and water(Fs-w),which effectively improve the wettability of modified coal dust via modifying its surface electrical properties and surface energy.A new type of wetting agent with a dust removal rate of 89%has been developed through discovery of a compound wetting agent solution with optimal wetting and settling performance.This paper provides theoretical and technical support for removing highly hydrophobic bituminous coal dust in underground mining.
文摘Experiments of soiling effects on the performances of a PV panel have been performed using dust collected from two sites in the region of Agadir-Morocco.The optical transmittance of the front glass was found to depend on the nature and density of dust.The nature of dust was studied by means of scanning electron microscopy and energy dispersive x-ray spectroscopy.It was found that the granulometry of dust particles depends on the study area.For a dust density of around 20 g/m^(2),the maximum power Pmax of the solar panel decreases drastically from 30 to 20 W for the(HP)site,and no more than 14 W for the(AD)site.The diversity of the behavior of the soiled panel was explained in terms of the size of the particles collected from each area.The transmission of light across the front glass of the PV panel is more affected when the sizes of particles are small.
基金supported by the Special Project for Sustainable Development Science and Technology of Shenzhen, China (2021N007)the Special Project for Red Imported Fire Ant Management, Shenzhen Agricultural Science and Technology Promotion Center, China (20220900044zbzjbc)。
文摘The red imported fire ant,Solenopsis invicta Buren,poses a significant threat to biodiversity,agriculture,and public health in its introduced ranges.While chemicals such as toxic baits and dust are the main methods for S.invicta control,toxic baits are slow,requiring approximately one or two weeks,but dust can eliminate the colony of fire ants rapidly in just three to five days.To explore more active ingredients for fire ant control using dusts,the toxicity of bifenthrin and dimefluthrin,the horizontal transfer of bifenthrin and dimefluthrin dust and their efficacy in the field were tested.The results showed that the LD50(lethal dose) values of bifenthrin and dimefluthrin were 3.40 and 1.57 ng/ant,respectively.The KT50(median knockdown time) and KT95(95%knockdown time) values of a 20μg mL^(–1)bifenthrin dose were 7.179and 16.611 min,respectively.The KT50and KT95of a 5μg mL^(–1)dimefluthrin dose were 1.538 and 2.825 min,respectively.The horizontal transfers of bifenthrin and dimefluthrin among workers were effective.The mortality of recipients (secondary mortality) and secondary recipients (tertiary mortality) were both over 80%at 48 h after 0.25,0.50 and 1.00%bifenthrin dust treatments.The secondary mortality of recipients was over 99%at 48 h after 0.25,0.50 and 1.00% dimefluthrin dust treatments,but the tertiary mortality was below 20%.The field trial results showed that both bifenthrin and dimefluthrin exhibited excellent fire ant control effects,and the comprehensive control effects of 1.00%bifenthrin and dimefluthrin dusts at 14 d post-treatment were 95.87 and 85.70%,respectively.
文摘Coal is the major source of power in India and world over.Coal mining is an essential industry which has a major role in the economic development of the country.Most major mining activities contribute directly or indirectly to air pollution.Coal dust is a major air pollutant which affects the personal working in the mines and also people residing in villages near the mines.Air pollution due to coal particulates can affect human health and cause damages to the environment.Hence effective pollution control mechanisms are needed to keep the pollution levels within permissible levels.The easiest and most common method employed for dust suppression worldwide is sprinkling of water.In majority of mines,water sprinklers are operated manually and can lead to wastage of water due to over sprinkling.It can also prove to be ineffective in dust suppression if sprinkling is not done properly.The paper proposes a system which can be deployed to automate the dust suppressions sprinklers.The system will monitor the concentration of PM_(10) and PM_(2.5) in the air and initiate sprinkling operation when the particulate matter content exceeds preconfigured limits.
基金This work was jointly supported by a project supported by the Joint Fund of the National Natural Science Foundation of China and the China Meteorological Administration(Grant No.U2242209)the National Natural Science Foundation of China(Grant No.42175106).
文摘Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and property.Against the backdrop of climate change,Mongolia’s contribution to China’s dust cannot be ignored in recent years.In this study,we used the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),along with dynamic dust sources and the HYSPLIT model,to analyze the contributions of different dust sources to dust concentrations in northern China in March and April 2023.The results show that the frequency of dust storms in 2023 was the highest observed in the past decade.Mongolia and the Taklimakan Desert were identified as two main dust sources contributing to northern China.Specifically,Mongolia contributed more than 42%of dust,while the Taklimakan Desert accounted for 26%.A cold high-pressure center,a cold front,and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China,where they affected most parts of the region.Moreover,two machine learning methods[the XGBoost algorithm and the Synthetic Minority Oversampling Technique(SMOTE)]were used to forecast the dust storms in March 2023,based on ground observations and WRF-Chem simulations over East Asia.XGBoost-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023,with a mean absolute error of 33.8μg m−3 and RMSE of 54.2μg m−3.
基金funded by the National Natural Science Foundation of China(52274237)the Fundamental Research Funds for the Central Universities(2021ZDPYYQ007)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_2656)the Graduate Innovation Program of China University of Mining and Technology(2022WLKXJ026).
文摘Single-fuid nozzles and dual-fuid nozzles are the two typical jet crushing methods used in spray dust reduction. To distinguish the atomization mechanism of single-fuid and dual-fuid nozzles and improve dust control efciency at the coal mining faces, the atomization characteristics and dust reduction performance of the two nozzles were quantitatively compared. Results of experiments show that, as water supply pressure increased, the atomization angle of the swirl pressure nozzle reaches a maximum of 62° at 6 MPa and then decreases, but its droplet size shows an opposite trend with a minimum of 41.7 μm. The water supply pressure helps to improve the droplet size and the atomization angle of the internal mixing air–liquid nozzle, while the air supply pressure has a suppressive efect for them. When the water supply pressure is 0.2 MPa and the air supply pressure reaches 0.4 MPa, the nozzle obtains the smallest droplet size which is 10% smaller than the swirl pressure nozzle. Combined with the dust reduction experimental results, when the water consumption at the working surface is not limited, using the swirl pressure nozzle will achieve a better dust reduction efect. However, the internal mixing air–liquid nozzle can achieve better and more economical dust reduction performance in working environments where water consumption is limited.
基金This work was supported by the National Natural Science Foundation of China(52074066).
文摘Wet dust removal systems used to control dust in the polishing or grinding process of Mg alloy products are frequently associated with potential hydrogen explosion caused by magnesium-water reaction.For purpose of avoiding hydrogen explosion risks,we try to use a combination of chitosan(CS)and sodium phosphate(SP)to inhibit the hydrogen evolution reaction between magnesium alloy waste dust and water.The hydrogen evolution curves and chemical kinetics modeling for ten different mixing ratios demonstrate that 0.4wt%CS+0.1wt%SP yields the best inhibition efficiency with hydrogen generation rate of almost zero.SEM and EDS analyses indicate that this composite inhibitor can create a uniform,smooth,tight protective film over the surface of the alloy dust particles.FTIR and XRD analysis of the chemical composition of the surface film show that this protective film contains CS and SP chemically adsorbed on the surface of ZK60 but no detectable Mg(OH)_(2),suggesting that magnesium-water reaction was totally blocked.Our new method offers a thorough solution to hydrogen explosion by inhibiting the hydrogen generation of magnesium alloy waste dust in a wet dust removal system.
基金supported by the Independent Research Fund of the State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines(No.SKLMRDPC20ZZ06)and the Program in the Youth Elite Support Plan in Universities of Anhui Province(No.gxyq2020013).
文摘The cyclone dust collector is an important subsystem of straw crushers used in agriculture.In the present study,a new type of dust collector with involute morphology is proposed to obtain better dust removal efficiency with respect to that of classical tangential and spiral dust collectors.A discrete phase model(DPM)method is used in synergy with a turbulence model,and the SIMPLE algorithm to simulate the flow field inside the dust collector and the related particle dynamics.It is shown that the internal flow field features a primary swirl,a secondary swirl and blockage effects.Moreover,for the involute dust collector,the tangential velocity in the initial stage and the pressure in the high-pressure area are larger than those obtained for the classical types.The dust removal efficiency is 37.11%,25.3%,and 16.37%for the involute type dust collector,the tangential type and the spiral type,respectively.
基金supported in part by the National Key R&D Program of China(Nos.2019YFE03080200,2022YFE03030001 and2022YFE03050003)National Natural Science Foundation of China(Nos.11975271,12075284,12075283 and 12175277)+1 种基金the Chinese Academy of President’s International Fellowship Initiative(No.2021VMA0022)the Post-CUP program,JSPS-CAS Bilateral Joint Research Projects,‘Control of wall recycling on metallic plasma facing materials in fusion reactor’,2019–2022,(No.GJHZ201984)。
文摘In the ELMy H-mode experiment,naturally occurring dust originating at the high-field side is clearly observed using the high-speed vacuum ultraviolet imaging system developed on the Experimental Advanced Superconducting Tokamak(EAST).The main ablation cloud shape is similar to the classical shape observed in pellet fueling experiments.However,during the dust penetration,an erupted secondary cloudlet with a bent‘cigar’shape is observed and moves upwards along the direction perpendicular to the magnetic field line,which is different to the obviation in the pellet fueling experiments.This may be due to the ion diamagnetic drift effect.The velocities of the secondary cloudlet are estimated to be 50–80 m s^(-1).In addition,a significant degradation of the plasma confinement is observed during the dust penetration.
基金supported by the National Natural Science Foundation of China(52174099)the Natural Science Foundation of Liaoning Province(2021-KF-23-01)the Fundamental Research Funds for the Central Universities of Central South University(2022ZZTS0510).
文摘A comprehensive evaluation method is proposed to analyze dust pollution generated in the production process of mines.The method employs an optimized image-processing and deep learning framework to characterize the gray and fractal features in dust images.The research reveals both linear and logarithmic correlations between the gray features,fractal dimension,and dust mass,while employing Chauvenel criteria and arithmetic averaging to minimize data discreteness.An integrated hazardous index is developed,including a logarithmic correlation between the index and dust mass,and a four-category dataset is subsequently prepared for the deep learning framework.Based on the range of the hazardous index,the dust images are divided into four categories.Subsequently,a dust risk classifcation system is established using the deep learning model,which exhibits a high degree of performance after the training process.Notably,the model achieves a testing accuracy of 95.3%,indicating its efectiveness in classifying diferent levels of dust pollution,and the precision,recall,and F1-score of the system confrm its reliability in analyzing dust pollution.Overall,the proposed method provides a reliable and efcient way to monitor and analyze dust pollution in mines.
文摘The key for dust control of coal mine is to clarify the dust concentration distribution and sedimentation in different areas. Both similarity experiment and numerical simulation method have certain restrictions and are quite different from the actual situation on site. In order to study the dust sedimentation regularity of coal mine in large mining height, “filter membrane method” is adopted in this paper, i.e., to dry and weigh the filter membrane before and after sampling, collect the dust of respirable zone on mining face and calculate the dust concentration based on a main airway of 100 m. The result shows that: A large amount of dust will be produced during coal mining, wherein the maximum dust concentration from 6 m upstream to 100 m downstream of coal cutter is 121 mg/m3</sup>, while the minimum dust concentration is 61 mg/m3</sup>;The dust concentration in return airway is reduced with the distance increases, while the dust concentration at the entrance is 91 mg/m3</sup>;A large amount of dust may fall from roof during section advancing and improves the dust concentration of hydraulic support in walking area obviously;The dust granularity of mining face and return airway is 0 - 100 μm, but the amount of respirable dust is higher than 80%, the larger the dust particle size, the higher the dust concentration. Besides, dust in small particle size can be suspended in air flow for longer, but that in large particle size may subside under the action of gravity;To reduce dust exposure, the mining position shall be located in the windward direction of advancing or coal cutter. This research can provide guidance for taking dust prevention measures of working face in large mining height.
基金the National Key R&D Program of China(Grant No.2018YFA0404502)the National Natural Science Foundation of China(Grant Nos.11821303,11733002,11973030,11673015,11733004,11761131004,and 11761141012).
文摘As one of the three major experiments of the fourth-generation Sloan Digital Sky Survey(SDSS-IV),the Mapping Nearby Galaxies at Apatch Point Observatory(MaNGA)survey has obtained high-quality integral field spectroscopy(IFS)with a resolution of 1–2 kpc for104galaxies in the local universe during its six-year operation from July 2014 through August 2020.It is crucial to reliably measure the physical properties of the different components in each spectrum before one can use the data for any scientific study.In the past years we have made lots of efforts to develop a novel technique of full spectral fitting,which estimates a model-independent dust attenuation curve from each spectrum,thus allowing us to break the degeneracy between dust attenuation and stellar population properties when fitting the spectrum with stellar population synthesis models.We have applied our technique to the final data release of Ma NGA,and obtained measurements of stellar population properties and emission line parameters,as well as the kinematics and dust attenuation of both stellar and ionized gas components.In this paper we describe our technique and the content and format of our data products.The whole dataset is publicly available in Science Data Bank with the link https://doi.org/10.57760/sciencedb.j00113.00088.