Search

In this paper, the removal behavior of alkali and alkaline earth metals (AAEMs) and the evolution of microscopic characteristics in high alkali coal under the leaching of inorganic and organic acids are studied. The results show inorganic acids have better effect on the removal of AAEMs because of their stronger ability to convert carboxylate and phenol salts into covalent carboxylic acids and phenols. Citric acid has a slightly weaker effect than inorganic acids, and oxalic acid has the least effect. The improvement of slagging characteristics is consistent with the removal ability. Sulfuric acid, hydrochloric acid and citric acid are more effective in enhancing the calorific value of coal, with an enhancement of about 0.60 MJ/kg. After leaching, the pores and cracks in the coal are developed, and the mesopores have a tendency to shift to a lower pore size range. This trend is most pronounced in citric acid leached coal and hydrochloric acid leached coal. Sulfuric acid seriously damage the surface morphology, which results in a tendency of large pore transfer in S-form coal. [ABSTRACT FROM AUTHOR]

Low-rank coal drying plays a crucial role in achieving clean and efficient coal utilization. This study introduces steam flash drying, a novel method specifically designed for upgrading low-rank coal. Unlike conventional drying techniques, steam flash drying utilizes steam as the heat medium, generating a certain amount of condensation. This paper presents a comprehensive analysis of the calculated condensate quantity and the experimental measurement of coal particles' water-holding capacity to determine the initial moisture content before drying. Furthermore, the study investigates the steam flash drying effect on different-sized coal particles at a temperature of 497 K. The findings demonstrate that particles above 3 mm have lower water-holding capacity. The initial moisture content is determined by the particles' water-holding capacity and the combined raw coal water content and condensate content. The research reveals a diminishing flash-drying effect with increasing particle size, characterized by a rapid decrease followed by a gradual decline, observed at a critical point of 6 mm. By strategically adjusting the particle size distribution and employing mixing techniques, the coal drying effect can be significantly enhanced by 22%, ultimately leading to a remarkable 17% increase in processing capacity per unit volume. As a result, this study provides a theoretical foundation and optimization strategies for the clean and efficient utilization of coal through steam flash drying. [Display omitted] • A novel steam flash drying method utilizing steam as the heat medium was proposed. • An initial moisture content model was developed, incorporating both condensed water and water-holding capacity. • Steam flash drying proves effective for upgrading coarse-grained coal particles. • Strategic adjustment of particle size distribution enhances drying efficiency for 3-0 mm particles and boosts processing capacity. [ABSTRACT FROM AUTHOR]

This study investigated the ash reduction and quality improvement effects of four types of ionic liquids on Zhundong high-alkali coal, focusing on the evolution laws of coal ash melting and combustion performance under the ionic liquid system, which provided a theoretical basis for the subsequent utilization of high-alkali coal. Ionic liquids can effectively reduce inorganic mineral content and volatile matter yield, increase fixed carbon and oxygen content in coal, and reduce hydrogen and sulfur content. The silicon-aluminum ratio of coal ash increased, and the content of low-melting minerals in coal ash decreased, while the content of refractory minerals increased, leading to an increase in the melting temperature of coal ash. Ionic liquids can inhibit the oxidation reaction of coal, which is beneficial for suppressing spontaneous combustion of coal and improving safety during storage and transportation. [ABSTRACT FROM AUTHOR]

There is increasing evidence suggesting that dysregulation of miR-155 and its target angiotensin receptor type 1 (AT1R) are linked to the incidence of ischemic stroke (IS), but the underlying mechanisms remain to be clarified. In this study, we therefore sought to investigate how miR-155 and AT1R polymorphisms affect IS risk. We included 579 IS patients and 509 age-matched controls in the present analysis, genotyping individuals for the rs767649 polymorphism in miR-155, as well as for the rs1492099 and rs275653 polymorphisms in AT1R via iMLDR-TM genotyping technology. The allele and genotype frequencies for the assessed polymorphisms were comparable in IS patients and controls, without any detectable association between AT1R haplotype and IS risk. We conducted additional trial of ORG 10172 in acute stroke treatment-mediated stratification, which indicated that the AT1R rs1492099 T allele was linked to a decreased risk of large-artery atherosclerosis (LAA) stroke. We further found that those with the AT1R rs275653 AA genotype had a decreased risk of small-artery occlusion (SAO) strokes. We further confirmed elevated miR-155 expression in IS patients, but observed no link between the rs767649 polymorphism and expression of this microRNA. Similarly, rs1492099 and rs275653 polymorphisms did not impact AT1R expression levels. The miR-155 rs767649 polymorphism does not seem to be a key determinant of IS risk, whereas the AT1R rs1492099 polymorphism is linked to reduced LAA-stroke risk, and the rs275653 AA genotype is potentially protective against SAO strokes. [ABSTRACT FROM AUTHOR]

As a crucial power source, the separation of fine coal has gradually become a research focus in the coal separation field. In this study, the vibratory combined force field fluidized bed has been introduced into fine coal (6–0.5 mm) separation research. The kinematic characteristics of the fluidized bed was studied. The spatial distribution of coal on the bed under the action of vibration and air was clarified. The influence of different factors on the degree of ash segregation (Sash) was analyzed, and the optimal operation parameters were evaluated. The results showed that the vibratory combined force field fluidized bed was characterized by round-trip periodic movement. The maximum vibration amplitude on the X-axis of the main vibration direction was 6.88 mm, the velocity amplitude was 287.60 mm/s, and the acceleration amplitude was 10.43 m/s2. At 34 Hz and 5.68 m/s for vibration frequency and air speed, the maximum ash segregation of the product was 1.896, and the yield and ash contents were 85.28% and 10.69%, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • The bed density is not evenly distributed in axial and radial directions. • BP neural networks are used to predict bed density in gas–solid fluidized beds. • BP neural network prediction model is optimized by genetic algorithm. • The accuracy of GA-BP neural network for bed density can reach more than 90 %. The fluctuation of bed density in the process of mineral separation in gas–solid fluidized bed is particularly critical, and accurate prediction of bed density will play a crucial role in industrial production. In this paper, the axial and radial distribution of bed density in gas–solid fluidized bed under different ratios of dense medium and gas velocities was investigated. Based on the data of this study and other scholars, the corresponding data set was constructed. A 13–14-1 bed density prediction model was established by using BP neural network algorithm. The overall correlation of the model is 0.9771. The model is more accurate to predict the bed density of single dense medium. The mean absolute percentage error is 4.17 % and the root mean square error is 0.0298. The optimized GA-BP (Genetic Algorithm-Back Propagation) neural network by genetic algorithm results are closer to the actual experimental values. The overall correlation of the model is increased to 0.9793, and the prediction accuracy can reach more than 90 %. The GA-BP neural network prediction model is more accurate in predicting fluidized beds with density fluctuation range of 1.6–2.2 g/cm3, which can meet the needs of industrial applications. [ABSTRACT FROM AUTHOR]

Background/Aims: Matrix metalloproteinase 9 (MMP9), a potent endopeptidase degrading extracellular matrix, plays a pivotal role in the pathogenesis of ischaemic stroke (IS). The present study was undertaken to determine the association of MMP9 gene polymorphisms and the risk of IS in a southern Chinese population. Methods: A cohort of 1274 patients and 1258 age-matched healthy controls were genotyped to detect the four MMP9 polymorphisms (rs17156, rs3787268, rs3918241 and rs3918242) using SNaPshot. Results: Our study demonstrated a significant difference in the genotype and allele frequencies of the MMP9 rs3918242 polymorphism between the IS patients and the controls (P = 0.012 for the genotype and P = 0.0092 for the allele). Stratification by smoking status showed statistically significant differences in the frequency and allele of the rs3918242 polymorphism between IS patients and the controls (P = 0.0052 for the genotype and P = 0.0019 for the allele). Further stratification by IS subtypes revealed that the presence of the T allele of the MMP9 rs3918242 polymorphism confers a higher risk of the large artery atherosclerosis subtype of IS (P = 0.017). Moreover, IS patients with the rs3918242 T allele of MMP9 presented with increased serum MMP9 production, and this increase was more significant in smokers with IS (P = 0.022). Patients carrying the variant T allele of the MMP9 rs3918242 polymorphism exhibited significantly higher infarct volumes than those with the major CC genotype (P = 0.036). Conclusion: Our study provides preliminary evidence that the MMP9 rs3918242 polymorphism is linked to a higher risk of IS, confirming the role of MMP9 in the pathophysiology of IS, with potentially important therapeutic implications. [ABSTRACT FROM AUTHOR]