Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 94
Filtrar
1.
Environ Sci Pollut Res Int ; 31(43): 55099-55118, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39243327

RESUMEN

The quest for scientifically advanced and sustainable solutions is driven by growing environmental and economic issues associated with coal mining, processing, and utilization. Consequently, within the coal industry, there is a growing recognition of the potential of microbial applications in fostering innovative technologies. Microbial-based coal solubilization, coal beneficiation, and coal dust suppression are green alternatives to traditional thermochemical and leaching technologies and better meet the need for ecologically sound and economically viable choices. Surfactant-mediated approaches have emerged as powerful tools for modeling, simulation, and optimization of coal-microbial systems and continue to gain prominence in clean coal fuel production, particularly in microbiological co-processing, conversion, and beneficiation. Surfactants (surface-active agents) are amphiphilic compounds that can reduce surface tension and enhance the solubility of hydrophobic molecules. A wide range of surfactant properties can be achieved by either directly influencing microbial growth factors, stimulants, and substrates or indirectly serving as frothers, collectors, and modifiers in the processing and utilization of coal. This review highlights the significant biotechnological potential of surfactants by providing a thorough overview of their involvement in coal biodegradation, bioprocessing, and biobeneficiation, acknowledging their importance as crucial steps in coal consumption.


Asunto(s)
Biodegradación Ambiental , Carbón Mineral , Tensoactivos , Tensoactivos/química , Biotecnología
2.
Environ Sci Pollut Res Int ; 31(43): 55437-55446, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39230816

RESUMEN

The extraction of coal from open-pit mines significantly contributes to environmental degradation, posing grave risks to human health and the operational stability of machinery. In this milieu, microbial dust suppressants leveraging microbially induced carbonate precipitation (MICP) demonstrate substantial potential for application. This manuscript undertakes an exploration of the dust mitigation efficiency, consolidation attributes, and the fundamental mechanisms of microbial dust suppressants across coal dust samples with varying metamorphic gradations. Empirical observations indicate that, in resistance tests against wind and rain, lignite coal underwent mass losses of 7.43 g·m-2·min-1 and 98.62 g·m-2·min-1, respectively. The production of consolidating agents within the lignite dust, attributable to the microbial suppressants, was measured at 0.15 g per unit mass, a value of 1.25 and 1.07 times greater than that observed in bituminous coal and anthracite, respectively. Scanning electron microscopy coupled with X-ray energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD) analyses illuminated that the consolidating products within the coal dust predominantly constituted calcite and vaterite forms of calcium carbonate. The consolidation mechanism of coal dust via microbial suppressants is articulated as follows: Subsequent to the application on coal dust, the suppressants induce the formation of carbonate precipitates with inherent adhesive properties. These carbonates affix to the surfaces of coal dust particles, progressively encapsulating them. Furthermore, they play a pivotal role in bridging and filling the interstices between adjacent dust particles, thereby culminating in the genesis of a dense, cohesive mass capable of withstanding erosive forces.


Asunto(s)
Carbón Mineral , Polvo
3.
J Hazard Mater ; 477: 135340, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-39096642

RESUMEN

Over the past two decades, the rise in coal worker's pneumoconiosis has prompted research into the effects of respirable coal dust components. This study explores how coal-pyrites produce hydroxyl radicals (•OH), a reactive oxygen species closely associated with particle toxicity, and assesses the ability of safe chemical additives to reduce •OH production at various pH levels. Promising candidates were evaluated in various solutions, including tap and process waters and simulated lung fluid. We employed electrokinetic measurements, infrared and X-ray photoelectron spectroscopies, and ab initio atomistic simulations to analyze particle surfaces. The study also looked at how surface aging affects •OH production. Our results show that •OH generation of the pyrite varies and is catalyzed by elements like silicon, aluminum, and iron in pyrite. Carboxymethyl cellulose was effective in reducing •OH production by targeting surface sulfide and silicon sites and affecting surface hydration and charge. Atmospheric aging was found to increase •OH production, especially in the pyrite with high iron and silicon and low calcium contents, relative to other samples. This highlights the role of the pyrite surface properties and chemical composition, and the solution pH and composition in •OH generation by coal-pyrites.

4.
Environ Geochem Health ; 46(9): 319, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39012521

RESUMEN

Pneumoconiosis is the most common occupational disease among coal miners, which is a lung disease caused by long-term inhalation of coal dust and retention in the lungs. The early stage of this disease is highly insidious, and pulmonary fibrosis may occur in the middle and late stages, leading to an increase in patient pain index and mortality rate. Currently, there is a lack of effective treatment methods. The pathogenesis of pneumoconiosis is complex and has many influencing factors. Although the characteristics of coal dust have been considered the main cause of different mechanisms of pneumoconiosis, the effects of coal dust composition, particle size and shape, and coal dust concentration on the pathogenesis of pneumoconiosis have not been systematically elucidated. Meanwhile, considering the irreversibility of pneumoconiosis progression, early prediction for pneumoconiosis patients is particularly important. However, there is no early prediction standard for pneumoconiosis among coal miners. This review summarizes the relevant research on the pathogenesis and prediction of pneumoconiosis in coal miners in recent years. Firstly, the pathogenesis of coal worker pneumoconiosis and silicosis was discussed, and the impact of coal dust characteristics on pneumoconiosis was analyzed. Then, the early diagnostic methods for pneumoconiosis have been systematically introduced, with a focus on image collaborative computer-aided diagnosis analysis and biomarker detection. Finally, the challenge of early screening technology for miners with pneumoconiosis was proposed.


Asunto(s)
Minas de Carbón , Polvo , Humanos , Neumoconiosis , Antracosis/epidemiología , Exposición Profesional/efectos adversos , Biomarcadores , Carbón Mineral , Enfermedades Profesionales/etiología , Enfermedades Profesionales/epidemiología
5.
J Hazard Mater ; 476: 135226, 2024 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-39029186

RESUMEN

The increasing prevalence of coal mine dust-related lung diseases in coal miners calls for urgent and meticulous scrutiny of airborne respirable coal mine dust (RCMD), specifically focusing on particles at the nano-level. This necessity is driven by expanding research, including the insights revealed in this paper, that establish the presence and significantly increased toxicity of nano-sized coal dust particles in contrast to their larger counterparts. This study presents an incontrovertible visual proof of these tiny particulates in samples collected from underground mines, utilizing advanced techniques such as scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The intricate elemental composition of nano-sized coal dust identified through EDS analysis reveals the presence of elements such as silica and iron, which are known to contribute to lung pathologies when inhaled over prolonged periods. The outcomes of the statistical analyses reveal significant relationships between particle size and elemental composition, highlighting that smaller particles tend to have higher carbon content, while larger particles exhibit increased concentrations of elements like silica and aluminum. These analyses underscore the complex interactions within nano-sized coal dust, providing critical insights into their behavior, transport, and health impacts. The nano-sized coal dust could invade the alveoli, carrying these toxic elements from where they are impossible to exhale. The revelation of nano-sized coal dust's existence and the associated health hazards necessitate their incorporation into the regulatory framework governing the coal mining industry. This study lays the groundwork for heightened protective measures for miners, urging the invention of state-of-the-art sampling instruments, comprehensive physicochemical profiling of RCMD nanoparticles, and the pursuit of groundbreaking remedies to neutralize their toxic impact. These findings advocate for a paradigm shift in how the coal mining industry views and handles particulate matter, proposing a re-evaluation of occupational health standards and a call to action for protecting coal miners worldwide.


Asunto(s)
Minas de Carbón , Carbón Mineral , Polvo , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Polvo/análisis , Carbón Mineral/análisis , Exposición Profesional/análisis , Espectrometría por Rayos X , Región de los Apalaches , Nanopartículas/análisis , Nanopartículas/química , Contaminantes Ocupacionales del Aire/análisis , Humanos
6.
Sci Rep ; 14(1): 16822, 2024 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-39039097

RESUMEN

Aiming at the three-body contact problem of mechanical rough surface containing wet coal dust interface, the three-body contact model of rough surface containing wet coal dust interface is constructed by comprehensively considering the contact deformation of rough surface and contact characteristics of wet coal dust, and based on the crushing theory. By analysing the contact force, load-bearing particle size and adjacent contact angle thresholds of the wet coal dust layer, the force chain identification criterion is formulated. Finally, quantitative calculations of the force chain characteristics are performed to reveal the effect of different initial porosities on the three-body contact stiffness, which is verified experimentally. The results of the study show that the average contact force of the wet coal dust layer can be used as the force chain contact force threshold, the average particle size can be used as the force chain particle size threshold, and the force chain angle threshold is determined by the particle coordination number. As the initial porosity decreases, the number, length and stiffness of force chains in the wet coal dust layer increase significantly, and the stiffness reaches a maximum value of 2.007 × 108 pa/m at the moment of downward pressure to stabilisation, while the trend of force chain bending varies in the opposite direction, and its minimum bending degree decreases to 20°. The maximum relative error between the simulation and experimental results of three-body contact stiffness is 9.64%, which proves the accuracy of the force chain identification criterion and the quantitative calculation of three-body contact stiffness by force chain.

7.
Sci Total Environ ; 946: 174202, 2024 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-38925396

RESUMEN

Coal dust (CD) is a common pollutant, and epidemiological surveys indicate that long-term exposure to coal dust not only leads to the occurrence of pulmonary diseases but also has certain impacts on cognitive abilities. However, there is little open-published literature on the effects and specific mechanisms of coal dust exposure on the cognition of patients with Mild Cognitive Impairment (MCI) and Alzheimer's Disease (AD). An animal model has been built in this study with clinical population samples to explore the changes in neuroinflammation and cognitive abilities with coal dust exposure. In the animal model, compared to C57BL/6 mice, APP/PS1 mice exposed to coal dust exhibited more severe cognitive impairment, accompanied by significantly elevated levels of neuroinflammatory factors Apolipoprotein E4 (AOPE4) and Interleukin-6 (IL6) in the hippocampus, and more severe neuronal damage. In clinical sample sequencing, it was found that there is significant upregulation of AOPE4, neutrophils, and IL6 expression in the peripheral blood of MCI patients compared to normal individuals. Mechanistically, cell experiments revealed that IL6 could promote the phosphorylation of ERK1/2 and enhance the expression of transcription factor SP1, thereby promoting AOPE4 expression. The results of this study suggest that coal dust can promote the upregulation of IL6 and AOPE4 in patients, exacerbating cognitive impairment.


Asunto(s)
Carbón Mineral , Disfunción Cognitiva , Polvo , Interleucina-6 , Ratones Endogámicos C57BL , Disfunción Cognitiva/inducido químicamente , Animales , Ratones , Interleucina-6/metabolismo , Sistema de Señalización de MAP Quinasas , Factor de Transcripción Sp1/metabolismo , Humanos , Transducción de Señal , Enfermedad de Alzheimer , Masculino
8.
Environ Pollut ; 351: 124041, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38685552

RESUMEN

The use of surfactants is crucial for the prevention and control of coal dust pollution in coal mining operation areas, yet there still exist many challenges in the control of coal dust pollution. In this paper, the green biomass-based amino acid surfactant sodium myristoyl glutamate (SMG) and the anionic surfactant sodium α-alkenyl sulfonate (AOS) were selected to investigate the improvement of coal dust wettability by single and binary solutions from the macroscopic and microscopic perspectives. Molecular simulations were used to reveal the microscopic mechanism of the wettability of coal dust by the different solutions. Experimental measurements showed that the contact angle of the AOS + SMG aqueous solution was as low as 13.8° on a coal surface. Coating the coal dust with the AOS + SMG solution reduced the surface tension by 12.02% compared to coating the coal with a single component solution. Additionally, the use of the binary AOS + SMG solution increased the hydrophilic group content in the coating by 11.77% compared to a single component solution, and the linkage between hydrophilic groups was enhanced, which pulls the water molecules to wet the coal dust. These research results should provide a new way to promote more environmentally friendly coal dust pollution control technology.


Asunto(s)
Carbón Mineral , Polvo , Tensoactivos , Polvo/análisis , Tensoactivos/química , Aminoácidos/química , Humectabilidad , Alcanosulfonatos/química , Minas de Carbón , Contaminación Ambiental/prevención & control
9.
Sci Rep ; 14(1): 7324, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38538737

RESUMEN

To discuss the inhibitory effect of micrometer scale coal dust explosion pressure, three types of explosion suppressants are selected for mixed explosion suppression. The results indicate that the coal dust explosion process includes three stages: accelerated and decelerated energy release, as well as energy dissipation. When using explosive suppressants, K2CO3 has the greatest inhibitory effect on coal dust explosion, followed by KCl, and CaCO3 has the smallest effect. The K2O, K2O2, and KOH generated by the thermal decomposition of K2CO3 can also block the heat transfer of coal dust, playing a good role in suppressing explosions. The explosion suppression effect of mixing CaCO3 and K2CO3 is better than that of mixing CaCO3 and KCl, and is worse than the explosion suppression effect of using K2CO3 alone. The synergistic effect of KCl and K2CO3 mixed explosion suppression makes the suppression effect better than using K2CO3 alone. This is because KCl generates K2O during pyrolysis, promoting the dynamic equilibrium of K2CO3 explosion suppression process. This makes mixed explosion suppression more worthy of attention and adoption when considering purchase costs.

10.
Artículo en Chino | MEDLINE | ID: mdl-38403418

RESUMEN

Objective: To study and compare the occupational exposure limits (OELs) of coal dust between China and foreign countries, understand the OEL of coal dust in China, and provide data and basis for revising the OEL of coal dust in China. Methods: In August 2023, by searching the official websites of limits setting institutions in relevant countries and regions at home and abroad, collecting and sorting out the OELs of coal dust issued by 10 limit setting institutions in 6 countries and the background information of the formulation, and conducting specific analysis on the classification, limit level and formulation principles of coal dust OEL in each country/institution. Results: In China and Japan, the total dust and respirable dust of coal dust OEL were established respectively, while in other countries, only the time-weighted average concentration (TWA) of respirable coal dust exposure was established. The TWA prescribed by China's Notional Health Commission, the United States Occupational Safety and Health Administration (OSHA) , the United States Mining Safety and Health Administration (MSHA) and the Australian Safety Work Bureau when the SiO(2) content was less than 5% were 5, 2.4, 2 and 3 mg/m(3) respectively. China GBZ 2.1-2019 sets the limit of 2.5 mg/m(3) for respirable coal dust with SiO(2) content less than 10%. The TWA set by the American Conference of Government Industrial Hygienists (ACGIH) and the South African Department of Mines and Energy (DME) for anthracite coal were 0.4 and 0.8 mg/m(3), respectively, and bituminous coal or lignite were 0.9 and 1.8 mg/m(3), respectively. The respirable coal dust TWA set by the National Institute for Occupational Safety and Health (NIOSH) in the United States was 1 mg/m(3), and the TWA set by the New Zealand Work Safety Authority was 3 mg/m(3). Conclusion: At present, the OEL of coal dust in China is at a relatively loose level, and it is suggested to further explore the possibility of revising coal dust OEL.


Asunto(s)
Contaminantes Ocupacionales del Aire , Minas de Carbón , Exposición Profesional , Estados Unidos , Dióxido de Silicio/análisis , Carbón Mineral , Australia , Exposición Profesional/prevención & control , Exposición Profesional/análisis , Polvo/análisis , China , Contaminantes Ocupacionales del Aire/análisis
11.
Ecotoxicol Environ Saf ; 271: 115972, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38218105

RESUMEN

Coal worker's pneumoconiosis (CWP) is a common occupational disease that coal miners are highly susceptible due to long-term exposure to coal dust particles (CDP). CWP can induce the accumulation of immune cells surrounding the bronchioles and alveoli in the lungs, resulting in pulmonary fibrosis and compromised immune function. Using single-cell RNA sequencing (scRNA-Seq), our previous studies disclose that CDP exposure triggers heterogeneity of transcriptional profiles in mouse pneumoconiosis, while Vitamin D3 (VitD3) supplementation reduces CDP-induced cytotoxicity; however, the mechanism by which how VitD3 regulates immune status in coal pneumoconiosis remains unclear. In this study, we elucidated the heterogeneity of pulmonary lymphocytes in mice exposed to CDP and demonstrated the therapeutic efficacy of VitD3 using scRNA-Seq dataset. The validation of key lymphocyte markers and their functional molecules was performed using immunofluorescence. The results demonstrated that VitD3 increased the number of naive T cells by modulating CD4 + T cell differentiation and decreased the number of Treg cells in CDP-exposed mice, thereby enhancing the cytotoxic activity of CD8 + effector T cells. These effects markedly alleviated lung fibrosis and symptoms. Taken together, the mechanism by which VitD3 regulates the functions of lymphocytes in CWP provides a new perspective for further research on the prevention and treatment of CWP.


Asunto(s)
Antracosis , Minas de Carbón , Neumoconiosis , Fibrosis Pulmonar , Animales , Ratones , Neumoconiosis/diagnóstico , Fibrosis Pulmonar/inducido químicamente , Carbón Mineral , Tolerancia Inmunológica
12.
Environ Res ; 244: 117956, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38128598

RESUMEN

In recent years, the preparation of new microbial dust suppressants based on microbial induced carbonate precipitation (MICP) technology through enriched urease-producing microbial communities has become a new topic in the field of coal dust control. The deposition of CaCO3 was the key to suppress coal dust. However, deposition characteristics in the field is not sufficient and the relationship between deposition characteristics and erosion resistance is not clear, which hinders the development of engineering application of new microbial dust suppressant. Therefore, based on X-CT technology, this paper observed and quantified micro-deposition of bio-consolidated coal dust with different calcium sources. Furthermore, a conceptual framework for deposition was proposed and its correlation with erosion resistance was revealed. The results showed that CaCO3 induced by calcium chloride and calcium lactate was aggregate deposited. Aggregate deposited CaCO3 was small in volume, showed the distribution of aggregation in the central area and loose outside, and mosaiced pores. CaCO3 induced by calcium nitrate was surface deposition due to attached biomass. Surface deposition was mostly large volume CaCO3 expanding from the inside out, which could cover coal dust to a high degree and completely cemented pores. In addition, the threshold detachment velocity of coal dust cemented by surface deposition was increased by 17.6-19.1% compared to aggregate deposition. This depended on the abundance and strength of CaCO3 bonding between coal dust particles under different deposition. The two-factor model based on porosity and CaCO3 coverage can well express relationship between erosion resistance and depositional characteristics. Those results will help the engineering application of MICP technology in coal dust suppression.


Asunto(s)
Carbón Mineral , Polvo , Polvo/análisis , Minerales , Biomasa , Calcio
13.
Cytokine ; 173: 156419, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-37976700

RESUMEN

Coal dust is the main occupational hazard factor during coal mining operations. This study aimed to investigate the role of macrophage polarization and its molecular regulatory network in lung inflammation and fibrosis in Sprague-Dawley rats caused by coal dust exposure. Based on the key exposure parameters (exposure route, dose and duration) of the real working environment of coal miners, the dynamic inhalation exposure method was employed, and a control group and three coal dust groups (4, 10 and 25 mg/m3) were set up. Lung function was measured after 30, 60 and 90 days of coal dust exposure. Meanwhile, the serum, lung tissue and bronchoalveolar lavage fluid were collected after anesthesia for downstream experiments (histopathological analysis, RT-qPCR, ELISA, etc.). The results showed that coal dust exposure caused stunted growth, increased lung organ coefficient and decreased lung function in rats. The expression level of the M1 macrophage marker iNOS was significantly upregulated in the early stage of exposure and was accompanied by higher expression of the inflammatory cytokines TNF-α, IL-1ß, IL-6 and the chemokines IL-8, CCL2 and CCL5, with the most significant trend of CCL5 mRNA in lung tissues. Expression of the M2 macrophage marker Arg1 was significantly upregulated in the mid to late stages of coal dust exposure and was accompanied by higher expression of the anti-inflammatory cytokines IL-10 and TGF-ß. In conclusion, macrophage polarization and its molecular regulatory network (especially CCL5) play an important role in lung inflammation and fibrosis in SD rats exposed to coal dust by dynamic inhalation.


Asunto(s)
Exposición por Inhalación , Neumonía , Ratas , Animales , Ratas Sprague-Dawley , Exposición por Inhalación/efectos adversos , Neumonía/inducido químicamente , Fibrosis , Polvo , Citocinas/metabolismo , Macrófagos/metabolismo , Carbón Mineral
14.
Materials (Basel) ; 16(19)2023 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-37834742

RESUMEN

Finding the solution to the problem of the accumulating waste from the mining and processing industries, as well as reducing their carbon footprint, is among the most important tasks today. Within the construction industry, in the field of the production of building materials such as concrete, these problems may be solved through the use of waste and by saving the binder component. The purpose of this study is to substantiate the feasibility of using waste coal dust (CD) in concrete and cement-sand mortars as a partial replacement for cement. Test samples were made by partially replacing cement with CD in an amount from 0% to 10% in increments of 2% by weight. The following main characteristics were studied: mobility and density of mixtures, as well as density, compressive strength, bending strength and water absorption of concrete and mortars. X-ray diffraction and microscopic analysis methods were used in this work. The introduction of CD to replace part of the cement, up to 10%, did not have a significant effect on the density of concrete and mortar mixtures but reduced their workability. The best values of physical and mechanical characteristics were recorded for concrete and mortar with 4% CD. The increases in the compressive strength of concrete and mortars were 6.6% and 5.7%, and in flexural strength 6.1% and 5.6%, respectively. Water absorption decreased by 9.7% for concrete and by 9.3% for mortar.

15.
Environ Sci Pollut Res Int ; 30(45): 101829-101840, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37658168

RESUMEN

A convection-type air curtain dust control system and method were proposed to effectively control the high dust concentrations generated during the operation of coal miners and hydraulic supports and to reduce the dust concentration in the entire working space of longwall work surfaces, and the effectiveness of air curtain dust control during single process operation was investigated through numerical simulation. The results showed that when the miner was working alone, there was a significant difference in the concentration distribution inside and outside the dust-proof air curtain, with significantly lower dust concentrations in the area where the miner drivers were operating compared to both sides, with an average dust mass concentration of around 420 mg/m3. Dust concentrations increased to about 700 mg/m3, but large amounts of dust were prevented from diffusing downwind. This indicates that the dust reduction effect is more pronounced after the equipment is opened, which can improve the working environment and reduce the probability of dust combustion and explosion accidents.

16.
Environ Sci Pollut Res Int ; 30(46): 102244-102259, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37665436

RESUMEN

Dust exposures during mining activity can result in lung diseases such as coal workers' pneumoconiosis (CWP) and silicosis, and it is closely related to quartz dust. In the present study, coal-quartz dust mixture were investigated considering the particle size and the specific constituents. Multiple numerical techniques, including computational fluid dynamics and discrete element method (CFD-DEM), hard sphere model, and direct Monte Carlo simulation (DSMC), were presented, and the dust diffusion processes were investigated. According to the validation of the numerical method, the suspension characteristics of the polydisperse mixed dust were analyzed in detail. The results show that PM10 responds quickly, has a large diffusion range, and is easily affected by the reflux. The particle size increases gradually from top to bottom. When the air velocity is low, the percentage of coal dust in the breathing zone tends to be 50%. The results provide theoretical guidance for the comprehensive prevention of the mixed dust in underground coal mines.


Asunto(s)
Antracosis , Minas de Carbón , Exposición Profesional , Humanos , Cuarzo , Carbón Mineral/análisis , Condiciones de Trabajo , Polvo/análisis
17.
Entropy (Basel) ; 25(8)2023 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-37628214

RESUMEN

To solve the problems of backward gas and coal dust explosion alarm technology and single monitoring means in coal mines, and to improve the accuracy of gas and coal dust explosion identification in coal mines, a sound identification method for gas and coal dust explosions based on MLP in coal mines is proposed, and the distributions of the mean value of the short-time energy, zero crossing rate, spectral centroid, spectral spread, roll-off, 16-dimensional time-frequency features, MFCC, GFCC, short-time Fourier coefficients of gas explosion sound, coal dust sound, and other underground sounds were analyzed. In order to select the most suitable feature vector to characterize the sound signal, the best feature extraction model of the Relief algorithm was established, and the cross-entropy distribution of the MLP model trained with the different numbers of feature values was analyzed. In order to further optimize the feature value selection, the recognition results of the recognition models trained with the different numbers of sound feature values were compared, and the first 35-dimensional feature values were finally determined as the feature vector to characterize the sound signal. The feature vectors are input into the MLP to establish the sound recognition model of coal mine gas and coal dust explosion. An analysis of the feature extraction, optimal feature extraction, model training, and time consumption for model recognition during the model establishment process shows that the proposed algorithm has high computational efficiency and meets the requirement of the real-time coal mine safety monitoring and alarm system. From the results of recognition experiments, the sound recognition algorithm can distinguish each kind of sound involved in the experiments more accurately. The average recognition rate, recall rate, and accuracy rate of the model can reach 95%, 95%, and 95.8%, respectively, which is obviously better than the comparison algorithm and can meet the requirements of coal mine gas and coal dust explosion sensing and alarming.

18.
Environ Sci Pollut Res Int ; 30(42): 95312-95325, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37542689

RESUMEN

In order to solve the hazard of coal mine dust, a dust-fixing agent (GC-TG-JFC) was prepared with gelatin, chitosan, octadecanol polyoxyethylene ether, and glutamine transaminase. The experimental conditions and the formulation were optimized by response surface method. The ratio of gelatin, chitosan, octadecanol polyoxyethylene ether, and glutamine transaminase was 0.405:0.211:0.095:0.286 and the dilution ratio was 1:30. The results of product performance test showed that the dust fixation rate could reach 99.95% when the wind speed was 9 m/s. The viscosity of the diluted solution was 42.5 mPa·s. The Forcite module in Materials studio software was used to analyze and calculate the radial distribution concentration, diffusion coefficient, and binding energy of the solution. The results showed that GC-TG-JFC migrated more water molecules to the surface of coal through the action of van der Waals force and hydrogen bond. In addition, the binding energy of water molecules increased and the diffusion coefficient decreased, which improved the binding ability of water molecules with coal. It could be found that GC-TG-JFC had good dust fixation performance by combining experiment and molecular dynamics method.


Asunto(s)
Quitosano , Minas de Carbón , Polvo/análisis , Gelatina , Minerales , Carbón Mineral/análisis , Polietilenglicoles , Éteres
19.
Sci Total Environ ; 900: 165913, 2023 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-37527714

RESUMEN

To study the influence pattern and efficiency enhanced mechanism of acoustic-chemical spray method on dust reduction, a self-developed acoustic excitation test platform, viscosity test, surface tension experiment and sinking experiments were used to investigate the chemical spray properties and the wetting behavior of coal dust excited by acoustic waves. The self-developed acoustic-chemical spray dust reduction simulation platform was used to study the influence of acoustic waves on coal dust reduction effect and its efficiency enhanced mechanism. The results showed that the surface tension and viscosity of the chemical spray solution fluctuated between 0.4 mN/m and 0.4 mPa·s along with the variations in acoustic wave frequency and sound pressure level (SPL), thereby confirming that acoustic waves had on effected on chemical spray solution properties. However, the wetting time of the chemical spray solution on coal dust increased by 33.64 % at an acoustic frequency (f) of 1300 Hz and SPL of 120 dB because of the liquid interface vibrations caused by acoustic waves. With an increasing of acoustic frequency, the dust reduction efficiency demonstrated a parabolic trend and reached its maximum value at f = 1300 Hz. The dust reduction efficiency also increased exponentially along with increasing SPL. Acoustic waves not only increased the collision frequency between particles and droplets by changing the trajectory of dust but also accelerated the wetting and agglomeration effect of chemical spray reagents on coal dust by causing vibrations at the gas-liquid interface, thereby enhancing the dust reduction efficiency. Compared to the dust reduction efficiency of chemical spray technology, the total dust reduction efficiency was increased by 8.53 %, and the respirable dust reduction efficiency was increased by 21.93 %. The effect of acoustic waves on the respirable dust reduction efficiency was more significant than that on total dust.

20.
Environ Res ; 237(Pt 1): 116803, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37532214

RESUMEN

Sea squirts, a tunicate, are found in all oceans and can foul marine ports and aquaculture, mainly affecting shipping and biodiversity. In this study, cellulose was extracted from sea squirts, and its hydrophilic properties were improved by substituting the hydrogen ions of the cellulose -OH with dopamine. The modified cellulose was used to prepare a hydrogel for use as a dust-fixing agent (CDP) to reduce air pollution caused by dust. After response surface method optimization, the proportions of binder, water-retaining agent, wetting agent, and antifreeze in CDP were 0.97, 1.44, 0.23, and 6.32%, respectively. This composition improved the wetting ability and permeability of CDP on particle surfaces. CDP exhibited good water retention at -11-50 °C. CDP reduced the wind erosion rate of dust at a wind speed of 12 m/s to 1.18%. The molecular dynamics method was used to analyze the wetting process and mechanism of CDP, revealing that hydrogen bonds were the dominant force at the solid-liquid interface. The adsorption of CDP onto the surface of coal increased the number of hydrophilic points. Water molecules were adsorbed on these hydrophilic points through hydrogen bonding, improving the binding energy between the solid and liquid interfaces. The application of ascidian cellulose in dust control makes full use of the biological value of ascidians, promoting sustainable development of the global biological economy.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA