Chemical Components Research Articles

Numerical Study of Air Cushion Effect in Notched Disk Water Entry Process Using Structured Arbitrary Lagrangian–Eulerian Method

This paper presents a novel numerical investigation into the air cushion effect and impact loads during the water entry of notched discs, utilizing the Structured Arbitrary Lagrangian–Eulerian (S-ALE) algorithm in LS-DYNA. Unlike prior studies that focused on smooth or unnotched geometries, the present study explores how varying notch parameters influence the fluid–solid coupling process during high-speed water entry. The reliability and accuracy of the computational method are validated through grid independence verification and comparisons with experimental data and empirical formulas. Systematic analysis of the effects of notch size, water entry velocity, and entry angle on the evolution of the free surface, impact loads, and structural responses uncovers several novel findings. Notably, increasing the notch diameter significantly enhances the formation and stability of the air cushion, leading to a considerable reduction in peak impact loads—a phenomenon not previously quantified. Additionally, higher water entry Froude numbers are shown to accelerate air cushion compression and formation, markedly affecting free surface morphology and force distribution. The results also reveal that varying the water entry angle alters the air cushion’s morphological characteristics, where larger angles induce a more pronounced but less stable air cushion, influencing the internal structural response differently across regions.

Gysinite-(Ce), PbCe(CO3)2(OH)(H2O), a New Member of the Ancylite Group

Abstract The new mineral gysinite-(Ce), PbCe(CO3)2(OH)(H2O) (IMA2023-035), was found at the Abendröthe Mine, St. Andreasberg, Braunlage, Goslar district, Lower Saxony, Germany, where it occurs in a single vug in association with albite, calcite, and mimetite. It is a secondary oxidation-zone mineral presumably crystallized from hydrothermal solutions. Gysinite-(Ce) occurs in intergrowths of equant pseudo-octahedral crystals, up to about 0.7 mm in maximum dimension. The color is brownish yellow, the streak is pale yellow, and the luster is vitreous to subadamantine. The mineral is brittle with curved, irregular fracture and no cleavage. The Mohs hardness is about 3½. The calculated density is 5.136 g/cm3. The mineral is biaxial (−) with α = 1.750(5), β = 1.825(5), γ = 1.860(5). The 2V is 65.1(4)° with no observable dispersion. The optical orientation is X = c; Y = a; Z = b by analogy with gysinite-(Nd) and there is no pleochroism. Electron probe microanalyses provided the empirical formula (Pb0.930Ce0.434La0.349Nd0.196Pr0.048Gd0.037Sm0.007)Σ2.000(CO3)2(OH)1.074(H2O)0.926. Gysinite-(Ce) is orthorhombic, Pmcn, a = 5.0780(4), b = 8.6689(6), c = 7.3255(6) Å, V = 322.47(4) Å3, and Z = 2. Gysinite-(Ce) is isostructural with gysinite-(La), gysinite-(Nd), and other members of the ancylite group. The crystal structure (R1 = 0.0268 for 396 I > 2σI) is a framework consisting of edge-sharing (PbCe)O8(OH)(H2O) polyhedra and CO3 triangles.

Monitoring of Overburden Failure with a Large Fractured-Height Working Face in a Deep Jurassic Coal Seam Based on the Electric Method

The development height of a water-flowing fractured zone is the key parameter to consider when carrying out mining under water pressure and coal mining with water conservation. In this paper, Jurassic coal seam 3-1 in the Menkeqing Coal Mine was taken as the research target, and a three-dimensional mining geological model was established by using FLAC3D to study the deformation and failure rules of overburden. Three roof boreholes were drilled in the auxiliary transportation roadway of adjacent working faces for dynamic monitoring by the resistivity method, which can better observe the whole process from failure to stability of the overburden. The results show that due to the complex sedimentary environment and large buried depth of coal seams in western China, there is a large deviation between the calculation results of the empirical formula of the fractured zone height under the “Regulations of buildings, water, railway and main well lane leaving coal pillar and press coal mining” (three regulations) and the simulation and on-site measurement. Based on the comprehensive analysis, the influence range of mining advance abutment pressure is approximately 60 m. The height of the water-flowing fractured zone is approximately 106 m, and it is located at the interface between sandy mudstone and mudstone. The height of the caving zone is approximately 22 m, and it is located at the interface between fine sandstone and medium sandstone. The ratio of the fractured height and coal seam thickness (Rf) reached 24.4, which was basically consistent with the test result of the adjacent Yushenfu mining area (which was 26 on average). There is no obvious change in the development height of the caving zone and water-flowing fracture zone from the working face to the drilling borehole position of more than 120 m, which reflects that the height of the overburden failure zone is related to the control of lithological combination.

Exploring the mechanism of Suxin Hugan Fang in treating ulcerative colitis based on network pharmacology

As a traditional Chinese medicine formula used in clinical practice for an extended period, Suxin-Hugan-Fang (SXHGF) exhibits excellent anti-inflammatory properties. However, the efficacy of SXHGF in treating ulcerative colitis (UC) and its mechanism of action are still unclear. In this study, the therapeutic effects of SXHGF on UC were evaluated using network pharmacology and experimental validation, while also investigating its mechanism of action. By administering DSS to C57BL/6 mice to construct a mouse model of ulcerative colitis, the therapeutic effect of SXHGF on ulcerative colitis was evaluated based on weight loss percentage, disease activity index, colon length changes, and pathological conditions as indicators. The main chemical components of SXHGF were determined by LC-MS-QTOF method. The potential targets and mechanisms of action of SXHGF in the treatment of UC were inferred using bioinformatics methods, and further validated through ELISA, IHC, and Western blotting assays. The experimental results demonstrate that SXHGF can suppress oxidative stress and oxidative damage in the colon tissue of UC mice, and alleviate DSS-induced ulcerative colitis by inhibiting the JAK2/STAT3 and NFκB pathways.

Chemical Profiles of Particulate Matter Emitted from Anthropogenic Sources in Selected Regions of China

Particulate matter (PM) emissions from anthropogenic sources contribute substantially to air pollution. The unequal adverse health effects caused by source-emitted PM emphasize the need to consider the discrepancy of PM-bound chemicals rather than solely focusing on the mass concentration of PM when making air pollution control strategies. Here, we present a dataset about chemical compositions of real-world PM emissions from typical anthropogenic sources in China, including industrial (power, industrial boiler, iron & steel, cement, and other industrial process), residential (coal/biomass burning, and cooking), and transportation sectors (on-road vehicle, ship, and non-exhaust emission). The data was obtained under the same strict quality control condition on field measurements and chemical analysis, minimizing the uncertainty caused by different study approaches. The concentrations of PM-bound chemical components, including toxic elements and PAHs, exhibit substantial discrepancies among different emission sectors. This dataset provides experimental data with informative inputs to emission inventories, air quality simulation models, and health risk estimation. The obtained results can gain insight into understanding on source-specific PMs and tailoring effective control strategies.

Regression prediction of tobacco chemical components during curing based on color quantification and machine learning

Color is one of the most important indicators to characteristic the quality of tobacco, which is strongly related to the variations of chemical components. In order to clarify the relationship between the changes of tobacco color and chemical components, here we established several prediction models of chemical components with the color values of tobacco based on machine learning algorithms. The results of correlation analysis showed that tobacco moisture content was highly significantly correlated with the parameters such as a*, H* and H°, the reducing sugar and total sugar content of tobacco was significantly correlated with the color values, and the starch content was highly significantly correlated with the color values except for b* and C*. The random forest models performed best in predicting tobacco moisture, reducing sugar, total sugar and starch constructed with the R2 of the model validation set was higher than 0.90, and the RPD value was greater than 2.0. The consistent between the predictions and measurements verified the availability and feasibility using color values to predict some chemical components of the tobacco leaves with high accuracy, and which has distinct advantages and potential application to realize the real-time monitoring of some chemical components in the tobacco curing process.

Development of novel mortar using fine river sand and pretreated waste flue gas desulfurization gypsum powder and pond fly ash

The objective of this study is to investigate the potential of combined pond fly ash (PFA) and flue gas desulfurization gypsum (FGDG) as a partial replacement for cement by mixing them with fine river sand for green mortar development. We studied the physical, mechanical, and microstructural properties of mortars by using techniques such as scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDXS) and X-ray diffraction (XRD) for chemical component identification of the hydrated phase. These experimental results show that mortar containing pond fly ash, FGDG, and cement concentrations of 5 wt%, 5 wt%, and 90 wt% yields the maximum compressive strength (8.9 MPa) and flexural strength (3.4 MPa) after 28 days. This mortar has 12.6% higher compressive strength and 48% lower shrinkage in comparison with control specimens. A reduction in shrinkage is attributed to the denser structure of the mortar, as the calcium silicate hydrate (C–S–H) gel is found to exist in the SEM image and also identified through XRD studies. It is also concluded that excessive ettringite formation causes expansion in the volume of mortar, voids formation, and results in the reduction of strength. The application of this mortar can be in the internal plaster, bricks, and masonry.

Based on Serum Pharmacochemistry and Metabolomics Studied the Pharmacodynamic Material Basis and Mechanism of Rubi Fructus (Fupenzi) in Improving the Symptom of Kidney-Yang Deficiency.

Rubi fructus (Fupenzi) is the immature fruit of East China Rubi fructus, which is widely used in medicine, food, health food and other fields. Since ancient times, Fupenzi has been considered to be an important medicine for tonifying the kidney in terms of nourishing the liver and kidney, fixing essence and reducing urine, but its effective components and mechanism are not clear. In this paper, the effective components of Rubi fructus were analyzed by detecting the components of Fupenzi in vivo and in vitro. Adenine was used to replicate the model of kidney yang deficiency, and organ index, biochemical index and histopathology were used to evaluate the effect of different doses of Fupenzi on tonifying kidney yang. Metabonomics technique was used to analyze the metabolic regulation mechanism of Fupenzi in improving kidney yang deficiency syndrome. The results showed that 61 chemical constituents of Fupenzi were identified in vitro, including 18 flavonoids, 19 organic acids, 5 coumarins, 8 terpenoids, 7 amino acids and 4 other components. A total of 51 chemical components were identified, including 30 prototype components and 21 metabolic components, which may be the effective components of Fupenzi. The results of pharmacodynamics showed that compared with the model group, the renal index, testicular index and epididymal index of rats in each Fupenzi group were significantly improved (p<0.01), cAMP significantly increased (p<0.05), cGMP decreased (p<0.05) and cAMP/cGMP ratio increased significantly (p<0.05). The content of ACTH in low dose group increased significantly (p<0.05), while the content of ACTH in middle and high dose groups increased, but there was no significant difference. The results of HE staining showed that compared with the model group, the kidney, testis and epididymis of rats in each treatment group were significantly improved. In general, these changes may be mainly through primary bile acid biosynthesis, linoleic acid metabolism, steroid hormone biosynthesis, β-alanine metabolism, glutathione metabolism, porphyrin and chlorophyll metabolism, unsaturated fatty acid biosynthesis, arachidonic acid metabolism, arginine and proline metabolism and other metabolic pathways to improve adenine-induced metabolic disorders in rats with kidney-yang deficiency syndrome.

Gradient variations of formation mechanisms and sources of PM1 at the steep slope from western SiChuan Basin to eastern Tibetan Plateau

Vertical distributions of chemical components of particulate matter (PM) are essential for better understanding the climate, environmental and health effects. The steep slope from western SiChuan Basin (SCB) to eastern Tibetan Plateau (TP) provides a good platform for obtaining the gradient variations of PM chemical components. Daytime and nighttime PM1 (particulate matter smaller than 1 μm) samples were collected with the medium-volume sampler at six sites with elevation ranging from 500 m to 3500 m (Chengdu, Sanbacun, Wenchuan, Lixian, Maerkang and Hongyuan). The secondary inorganic ions and carbonaceous aerosols were the largest contributor to PM1 concentrations. The chemical components from the anthropogenic sources existed strong stratification with high concentrations inside the basin, while primary natural ions showed little discrepancy among the sites. The concentrations of primary inorganic ions from anthropogenic sources were much higher at nighttime than daytime, which was contrary to the diurnal cycle of secondary inorganic ions. Spatial heterogeneity of PM chemical components was large between basin and plateau sites, especially for NO3− and NH4+, large depending on season and daylight. The excess NH4+ concentrations existed in spring, summer and fall, while SO42− and NO3− cannot be completely neutralized by NH4+ in winter. The proportion of secondary formation in all sources significantly increased from about 10 % to 30 %–40 % with the increased elevation, while the contribution of motor vehicles declined from western SCB to eastern TP. This study will fill the scarce observations of PM chemical components at the sloped terrain and deepen the understanding of formation mechanism of heavy pollution inside the basin.

Design of multi-hidden-layer Bayesian neural networks for model updating

Structural health monitoring (SHM) based on artificial neural networks (ANN) has received a lot of attention in recent decades, especially the Bayesian neural network (BNN) approach, which is more robust to noise for training and generalization. Since building a high-quality BNN architecture suitable for a specific task depends highly on user experience, the existing literature generally studies BNNs with simple single-hidden-layer architectures designed by empirical formulas or very few tailor-made algorithms. Multiple hidden layer BNN (MBNN) has a more complex architecture than single hidden layer BNN (SBNN) and is expected to achieve better generalization performance for complex problems. But the corresponding architectural design problem is much more complex, and there is no previous experience in the literature. To achieve this for MBNN, this paper proposes two feasible algorithms to optimize the number of neurons in each hidden layer simultaneously, where a logarithmic evidence metric is introduced to quantitatively characterize the performance of MBNN for a given multi-hidden-layer architecture. The feasibility and effectiveness of the proposed method are verified by the finite element (FE) model updating of both a planar truss model and a real-life pedestrian bridge. The verification results show that the second algorithm is much more computationally efficient for the optimal design of the MBNN architecture and has the potential for practical application.

Performance evaluation of ALIP applying fully enclosed slot

ABSTRACT In nuclear energy systems, annular linear induction pump (ALIP) is regarded as an ideal device for transporting liquid metal. Developed pressure and efficiency are crucial indicators for evaluating performance of an ALIP, and enhancing these fac- tors is of utmost importance. This paper presents a 2D axisymmetric finite element method (FEM) model for efficiently predicting the performance of ALIP and a 3D FEM model to explore the implementation of a fully enclosed slot structure. The accuracy of the proposed models is validated by comparing the results with experimental data, complemented by empirical formulas in the post-processing phase. The continuous and discontinuous conditions of the pole pieces are analyzed using the 3D FEM, demonstrating that the fully enclosed slot structure can significantly enhance both developed pressure and efficiency, thereby improving the overall performance of the ALIP.

Selection for agronomic traits in intermediate wheatgrass increases responsiveness to arbuscular mycorrhizal fungi

Societal Impact StatementAgricultural practices have had a negative impact on the physical, chemical, and biological components of soil. Perennial cropping systems that facilitate positive soil microbial interactions could not only rebuild soils but also sustain productivity through expected variations in environmental conditions. Here, we show the presence of arbuscular mycorrhizal (AM) fungi, soil symbionts that can improve host performance and soil health, increased the growth of intermediate wheatgrass, a novel perennial grain crop, in populations that have been increasingly bred for desirable agricultural characteristics. The right pairing of intermediate wheatgrass and a beneficial AM fungal community could lead to more sustainable agroecosystems.Summary Intermediate wheatgrass (IWG) is a novel perennial grain that can provide many soil health benefits in agroecosystems; however, little is known about how selection for agronomic traits has impacted interactions with soil biota. Here, we assess how the selection for agronomic traits in IWG has impacted its relationship with arbuscular mycorrhizal (AM) fungi. First, growth response to AM fungi was compared across five generations of IWG with varying degrees of selection. Second, variation in AM fungal responsiveness was compared among genets of IWG individuals within a more advanced generation. Finally, a meta‐analysis was performed on all published studies exploring AM fungal inocula effects on IWG performance to increase understanding of selection effects. AM fungal responsiveness increased with selection for agronomic traits, responsiveness varied among genets in the advanced generation, and a majority of genets performed better in the presence of AM fungi. The meta‐analysis supported the findings that AM fungal responsiveness has increased with selection in IWG. Further studies are needed to realize the combined potential soil health and sustainability benefits of IWG and AM fungi, including assessment of symbiotic benefits beyond biomass production, identification of IWG traits correlated with responsiveness, and characterization of AM fungal community response to IWG.

Superstatistical functions of modified shifted Morse potential for diatomic molecules

The application of the molecular potential model to the study of different thermodynamic systems has been a focus of interest in recent time due to its importance in molecular and chemical physics. Hence, the asymptotic iteration method and the Laguerre polynomials are employed to obtain the eigensolutions of the Schrödinger equation with the modified shifted Morse potential model. Vibrational energy results for different diatomic molecules have been presented numerically, and these results are compared with experimental data and other results from available literature. The variation of normalised wave function and probability density of modified shifted Morse potential for some selected diatomic molecules at the ground- and first-excited states have been considered. Results obtained show that the equally spaced sinusoidal wave curves and varying nodes depend on the level of electron concentrations in the diatomic molecules considered. Partition function and other superstatistical function expressions of modified shifted Morse potential for some diatomic molecules within the modified Dirac delta distribution are obtained, using the Poisson summation formula. The superstatistical plots show a high level of dependence on the temperature parameter, maximum vibrational quantum number and deformation parameter. The superstatistical functions for a deformation parameter of zero correspond to the conventional thermodynamic functions.

Decay of secondary electron yield of MgO–Au composite film at different incident electron energies

The relationship between the incident electron energy and secondary electron yield (SEY) decay of MgO–Au composite film was investigated by the designed comparison experiments. Besides the incident current and the properties of the film, the SEY value and the incident electron energy were found to be the other two key factors affecting the SEY decay rate. The value of SEY and the incident electron energy have opposite influences on the SEY decay rate, which makes it necessary to analyze the curve of incident electron energy versus SEY decay rate by dividing it into three parts. In addition, the empirical formulas for SEY decay were derived from experimental data, enabling the estimation of the SEY and decay rate of the MgO–Au composite film at any moment during SEY decay. Furthermore, the cause of SEY decay was also analyzed based on the relationship between incident electron energy and the SEY decay rate. The thermal dissipation, surface roughness, and deposition of contaminants were proven not to be the determinants of SEY decay. The experiment results in this paper supported the inference that the charging effect was the primary cause of SEY decay.

Three new members of the hakite series, Cu6(Cu4Me2+2)Sb4Se13: hakite-(Cd), hakite-(Fe) and hakite-(Zn) from the Bytíz deposit, uranium and base-metal Příbram ore district, Czech Republic

Abstract Hakite-(Cd), hakite-(Fe) and hakite-(Zn) are new minerals belonging to the tetrahedrite group and forming, along with hakite-(Hg), the hakite series. They have been discovered in samples collected from the Bytíz deposit, in the uranium and base-metal Příbram ore district, Central Bohemia, Czech Republic. They occur as anhedral grains, up to 300 μm in size, in a calcite gangue, associated with clausthalite, cadmoselite, hakite-(Hg) [for hakite-(Cd)], berzelianite, bukovite, bytízite, crookesite, chaméanite, eskebornite, příbramite, the not yet approved giraudite-(Hg) and giraudite-(Cu), hakite-(Hg), umangite, chalcopyrite, tetrahedrite-(Zn) and a new Cu–As selenide [for hakite-(Fe) and -(Zn)]. The three new species are black, with a metallic lustre. Mohs hardness is ca. 3½–4; calculated density is 6.019 (Hak-Cd), 6.011 (Hak-Fe) and 6.081 g.cm–3 (Hak-Zn). In reflected light, they are isotropic, pale grey with bluish (Hak-Cd) or brownish (Hak-Fe and Hak-Zn) shades. Empirical formulae of hakite-(Cd), hakite-(Fe), and hakite-(Zn) are Cu9.71Ag0.24Cd1.51Hg0.43Zn0.03(Sb3.94As0.13)Σ4.07Se11.35S1.57, Cu10.11Ag0.18Fe0.81Zn0.50Hg0.26(Sb3.72As0.41)Σ4.13Se12.65S0.12, and Cu10.03Ag0.24Zn0.61Fe0.53Hg0.45(Sb3.55As0.60)Σ4.15Se12.82S0.08, respectively. These formulae correspond to the end-member formulae Cu6(Cu4Cd2)Sb4Se13 (Hak-Cd), Cu6(Cu4Fe2)Sb4Se13 (Hak-Fe), and Cu6(Cu4Zn2)Sb4Se13 (Hak-Zn). All these new members of the hakite series are cubic, I $\bar{4}$ 3m, Z = 2, with unit-cell parameters a = 10.8860(6) Å, V = 1290.0(2) Å3 (Hak-Cd); a = 10.7983(4) Å, V = 1259.12(14) Å3 (Hak-Fe); and a = 10.8116(14) Å, V = 1263.8(5) Å3 (Hak-Zn). These species are isotypic with the other members of the tetrahedrite group, and their crystal structures have been refined on the basis of single-crystal X-ray diffraction data down to R1 values of 0.0230 (Hak-Cd), 0.0254 (Hak-Fe), and 0.0302 (Hak-Zn). These structural data allow us to describe the S-to-Se partitioning in hakite-series minerals and to understand the mechanisms avoiding too short Me–Se distances in these selenides.

Quickly Calculating the Activity Coefficient of a NaCl Solution Based on Machine Learning Algorithms.

The activity coefficient represents the deviation between an actual solution and an ideal solution, influencing the solubility and diffusion of CO2 within a saltwater layer. Consequently, it serves as a crucial parameter for numerical simulations of CO2 storage in deep saltwater layers. However, in numerical simulations of CO2 geological storage, the majority of studies rely on the Helgeson-Kirkham-Flowers (HKF) equation to compute activity coefficients, which necessitates obtaining Debye-Hückel (DH) parameters. The conventional method calculates the DH parameters via an interpolation algorithm, which requires a long computation time during the numerical simulation. Therefore, developing a method to quickly and accurately calculate activity coefficients is vital for the overall model efficiency. This study employed machine learning algorithms to train DH parameters derived from the IAPWS-95 method. It could establish empirical formulas for DH parameters as functions of temperature and pressure, which were then substituted into the HKF equation to swiftly compute activity coefficients. The results demonstrate that the activity coefficients obtained using this method exhibit a small relative deviation from experimental values, with an average coefficient of determination of 0.9463 and an average relative error of 2.28%. Furthermore, the computational speed was improved by 48%. This approach reduces the calculation time for activity coefficients in geochemical reaction modeling, enabling DH parameters to be calculated solely based on temperature and pressure, which is easy to use and has high accuracy. It facilitates rapid calculation of activity coefficients for solutions within a temperature range of 0 to 300 °C and a pressure range of 0 to 200 MPa. Ultimately, this study holds significant importance for the numerical simulation of geochemical reactions.

Characteristics of dissolved organic matter in water bodies during the dry season in the Huainan section of the Huaihe River Basin in Northern Anhui Province, China

This study investigated the spatial heterogeneity of dissolved organic matter (DOM) composition and characteristics in the central reaches of the Huaihe River Basin. The dry season DOM content and composition of three river bodies (the main stream of Huaihe River, the Huaihe tributaries and agricultural drainage ditches) in the Huaihe River Basin were studied using UV-Vis and three-dimensional fluorescence spectroscopy combined with parallel factor analysis (EEMs-PARAFAC). The degree of DOM humification and the relative molecular weight of tributaries and agricultural drainage ditches were significantly higher than those of the main stream (p < 0.01), and regarding the autogenetic characteristics of the three types of water bodies the tributaries and drainage ditches were more strongly affected by exogenous interference than the main stream. Three kinds of chemical components were determined by PARAFAC mode(C1:terrsstrial humus-like;C2:tryptophan-like;C3:protein-like), protein-like components were the main fluorescent components in DOM during the dry season, the proportion of different water systems exceeds 50%. Principal component analysis (PCA) showed that the fluorescence intensity of humus was closely related to the TP(Total phosphorus) concentration in the Huainan section water body of the Huaihe River Basin during the dry season. The absolute principal component-multiple linear regression model showed that the contribution of water nutrition to the C2 and C3 of protein-like fluorescent components was greater, while exogenous interference had a greater effect on the TP physicochemical index.

Study on the “Two-Zone” Heights in Lower Slice Mining Under Thick Alluvium and Thin Bedrock

The extraction of thin bedrock coal seams with thick alluvium poses a challenging issue in the realm of coal safety production in China. Especially for mining under aquifers, knowing the development height of water-conducting fracture zones above the goaf is crucial for coal mine safety and production. Taking the 11092 working face of lower slice mining in Zhaogu No. 1 Mine as an example, the failure transfer process of the overlying strata is analyzed first. On this basis, the development height of the water-conducting fracture zone is predicted using empirical formulas and the BP neural network. According to the empirical formula, the height of the roof caving zone ranges from 6.93 m to 27.72 m, while the height of the water-conducting fracture zone ranges from 22.17 m to 71.73 m. The BP neural network predicts that the development height of the water-conducting fracture zone in the working face after mining is 56.83 m. CDEM numerical simulation is employed to analyze the development height of two zones of overburden rock. The findings indicate that with a mining height of 2.5 m and a cumulative mining height of 6 m, the maximum caving ratio is 2.61. It is observed that for a cumulative mining thickness of less than 6 m, a bedrock thickness of not less than 30 m, and a clay layer thickness exceeding 5 m, the clay layer effectively obstructs the upward development of the water-conducting fracture zone. Finally, the prediction results of the development height of the two zones of overlying strata in the working face are verified by using the height observation method on the underground water-conducting fracture zone and the borehole peeping method. In conclusion, the height of the overlying strata after mining the lower slice working face in the first panel of the east can be used as a basis for determining the thickness of coal (rock) pillars for waterproofing and sand control safety during the mining of lower slice working faces in mines.

Characteristic of PM2.5 concentration and source apportionment during winter in Seosan, Korea

Seosan is a concentrated industrial complex in the midwestern region of Korea. A study was conducted from December 2020 to January 2021, measuring PM2.5 and chemical components in Seosan using online instruments every hour. The concentration of PM2.5 during the winter season was 31.4±17.8 μg/m3, exceeding the national ambient air quality standard of Korea. The mass fraction of organic matter, elemental carbon, three major ions, five minor ions, crustal elements, and trace elements in PM2.5 accounted for 24.5%, 4.36%, 32.0%, 2.82%, 4.11%, and 5.17% of the total PM2.5 mass concentration, respectively. Source identification was conducted using positive matrix factorization modeling, revealing eight sources of PM2.5: Secondary inorganic aerosol (SIA), vehicle exhaust, industry, coal combustion, biomass burning/incinerator, oil combustion, soil, and aged sea salt. Source contributions varied during high pollution episodes (HPE), with SIA dominating in HPE1 and soil and aged sea salt in HPE2. The potential source contribution function and conditional probability function were utilized to estimate the potential local and regional emission areas for the identified sources. In Seosan, vehicle exhaust and biomass burning/incinerator were primarily influenced by local sources. SIA, industry, and oil combustion sources were significantly affected by short-range transport from eastern China. Soil and aged sea salt, which exhibited high contributions during HPE2, were associated with long-range transport from Inner Mongolia. Coal combustion was attributed to both local sources, particularly large industrial complexes near Seosan, and long-range transport from Northeast China and Inner Mongolia.Graphical

The genus Derris Lour., a potential source of valuable biologically active ingredients

AbstractThis article summarizes the recent reports on the chemical components and biological activities of the genus Derris Lour. There are about 240 compounds isolated from this genus, including 31 rotenoids, 146 flavones and their derivatives (flavans, isoflavones, chalcones), 7 triterpenoids, 23 pterocarpans, 10 coumarins, and 34 other compounds. Many compounds have unique structures and exhibit potential biological effects including insecticides, antioxidant, antimicrobial, antifungal, antihyperglycemic, and cytotoxic activities. This review aims to systematically provide research results on the chemical composition and biological activities of Derris species.