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Coal spontaneous combustion (CSC) is one of the main sources of greenhouse gases (GHGs) emission. In order to understand the GHGs emissions law of the heating and quenching processes in the coal low-temperature oxidation stage, three kinds of coal samples with different degrees of metamorphism were selected to investigate the influence of particle size and oxygen concentration on GHGs emissions. Compared with the heating process, the greenhouse effect of CSC under different inerting conditions was determined. The results showed that the CO2 and CH4 were the mainly GHGs in the initial stage of the coal oxidation, which were emitted from the oxidation and desorption of coal, while the particle size of coal displayed the opposite effect on GHGs. By comparison with the heating process, the average emission factor and total emission of CO2 of 1/3 JM, the average emission factor and total emission of CH4 of HM with 21% O2 were higher in the quenching process. Meanwhile, with the decrease in oxygen concentration, the emission rate, average emission factor and total emission of GHGs decreased, and the greenhouse effect of CSC became weaker. Among them, the highest inerting rates of GHGs of HM, 1/3 JM and WYM reached 81.5%, 64.8% and 77.7%, respectively. In addition, the oxygen concentration was linearly positively correlated with the total emissions of CO2 and CH4, and conformed to the quadratic polynomial function with the equivalent CO2 emission factor. However, due to the strong displacement effect of N2, the emission rate, average emission factor and total emission of CH4 of WYM and 1/3 JM with 0% O2 were higher than those with 7% O2, and it is shown that inert gases can weaken the coal oxidation, diminished GHGs emissions, reduced the greenhouse effect of CSC on the environment, and enhanced the desorption of gases in coal. The research results have important practical significance for improving the incomplete emissions of GHGs in the low-temperature oxidation process, and evaluating the emission reduction effect of CSC prevention. [ABSTRACT FROM AUTHOR]

Wildland–urban interface fires are a severe fire hazard due to biomass ignition caused by arc beads. This study investigated how the energy, diameter, and number of arc beads affect biomass ignition probabilities. An improved experimental method was used to generate arc beads of various arc energies. Here, α-cellulose materials, which are well-characterised as biomass, were used as fuels. A high-speed camera recorded ignition phenomenology, revealing two ignition behaviours of rolling and embedding. The results revealed that an electrical fault arc energy of approximately 175 J was the most dangerous ignition condition. Ignition phenomenology was categorised into ignition and non-ignition, and it was observed that ignition could only occur during the bead rolling process. Contrarily, non-ignition occurred when its bounce even spun plenty of times. Ignition limits, namely the ignition region, potential ignition region, and non-ignition region, were determined. Furthermore, a novel predictive logistic regression-based ignition probability model was established, which indicated that the ignition occurrence of an arc bead was highly dependent on the diameter of the arc bead. The developed mathematical model can reasonably predict the ignition ability of biomass fuel ignition by arc beads. [ABSTRACT FROM AUTHOR]

• The spontaneous combustion tendency of coal was determined. • The evolution of functional groups was derived. • The addition of 2.0 mass% FeS 2 exerted a prominent promoting effect on coal oxidation. • The influence mechanism of FeS 2 on coal oxidation was determined. Spontaneous combustion of coal has become an important disaster that threatens the safety of coal mines. FeS 2 is the main component of pyrite, which is suspected to be a major contributor to coal spontaneous combustion (CSC). So, it has important significance to FeS 2 on the characteristics of coal oxidation for prevention and treatment. This study used coal samples mixed with different proportions of FeS 2 (2.0 mass%, 4.0 mass%, and 6.0 mass% mass percentage) were tested to investigate the characteristics of spontaneous combustion, as compared with the fresh sample. The CO and CO 2 production rates, critical temperature, and dry cracking temperature during oxidation were analyzed. The temperature-programmed experiments was conducted to simulate low-temperature oxidation processes realistically. In-situ infrared spectroscopy was used to appraise the evolution of low-temperature (< 200.0 °C) oxidation of aromatic hydrocarbons, aliphatic hydrocarbons, and oxygen-containing functional groups on the surfaces of the samples. Experimental results showed that FeS 2 exhibited a strong influence as the temperature exceeded the dry cracking temperature. Adding 2.0 mass% and 4.0 mass% FeS 2 showed a promoting effect on low-temperature oxidation; however, FeS 2 became an inhibitor which reached 6.0 mass%. Furthermore, adding 2.0 mass% FeS 2 showed the strongest promoting effect. From a microscale perspective, the promoting effect of FeS 2 on coal oxidation was due to thermal release from FeS 2 oxidation, enhancing the reaction between aliphatic hydrocarbons, such as methyl groups and methylene, and oxygen. Due to the reaction of FeS 2 , the acidic environment was conducive to the hydrolyzation of lipid structures into highly active alcohol or phenol structures, which in turn promoted the oxidation of the coal sample. These results are crucial for understanding the mechanism underlying the influence of FeS 2 on CSC and mine safety protocols. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ignition phenomenon of cellulose by electrical faults beads was investigated. • The ignition behaviors were determined from the experiments. • The numerical model was developed to predict the ignition characteristics. • The model described the mechanism of the ignition phenomenon reasonably well. Cellulose is the most abundant material and widely used fuel in the world, and on the other hand, it is also the risk of forest potential fire hazards. Fires caused by electrical arc beads, which are detrimental to the environment, occur in wildland-urban interface (WUI) areas. This study experimentally and numerically examined the ignition behavior of the cellulose fuel bed by focusing on arc beads. Experiments were conducted using authentic arc fault beads, and the effects of the bead temperature and implantation depth on ignition phenomena were investigated. Three ignition categories were determined: no, smoldering, and flaming ignition. Ignition temperature limits were determined by performing a statistical analysis, and experimental observations were used to develop a mathematical model. The two-step reaction leading to cellulose ignition was discussed, and natural convection, diffusion, and thermal radiation were all identified as influential parameters. Four ignition mechanisms were identified using the model: no ignition, smoldering or charring inside the fuel bed, smoldering leading to volatiles ignited, and flaming ignition. The ignition phenomenon was limited by the conduction and accumulation of heat, presence of volatile substances, and concentration of atmospheric oxygen. The model reasonably predicted the ignition phenomenon and described the ignition mechanism. These results can be used to reduce the risk of fire hazards related to arc beads, particularly in WUI areas. [ABSTRACT FROM AUTHOR]

To reduce the hazardous effect of coal fires, gas-heat dynamic characteristics were investigated in the closed fire zone. A temperature-programmed experiment and a C80 microcalorimeter were employed to evaluate the heating and decaying processes of coal spontaneous combustion, CO production and thermal oxidation were compared to analyze the gas-heat dynamic relationship and nonlinear dynamics. The results revealed that CO production and the heat flux exhibited obvious hysteresis in the decaying process, the oxygen concentration linearly increased with the total CO production and cumulative heat release. Moreover, the heat release in the heating process was lower than that in the decaying process under identical oxygen-poor conditions, this mechanism increasingly dominated with increasing oxygen concentration. Additionally, the total CO production exhibited a good linear relationship with the cumulative heat release during the heating process, the decaying process exhibited a nonlinear trend due to the hysteresis effect. Compared with that of the heating process, the apparent activation energy of the decaying process was lower, the coal spontaneous combustion risk was higher and reignition was more likely to occur. These research results are great practical significance for inhibiting coal fire hazards and guiding fire area unsealing in the closed fire zone. [Display omitted] • The heating and decaying processes of coal oxidation were simulated by experiments. • Correlation of CO and heat under various oxygen concentrations were analyzed. • Dynamic relationship of the heating and decaying processes was compared and analyzed. • The CO production and heat flux exhibited obvious hysteresis in the decaying process. • The decaying process of coal oxidation was more dangerous to reignite. [ABSTRACT FROM AUTHOR]

Highlights: [•] Neuroprotective effect of isoquercetin was studied in neuron OGD/R injury model. [•] The mechanism of isoquercetin relies on the anti-inflammation and anti-apoptosis. [•] TLR4 and NF-κB are involved in the anti-inflammatory signaling pathway. [•] ERK, JNK and p38 are involved in the anti-apoptotic signaling pathway. [•] Inhibition of caspase-3 contributes to the improvement from OGD/R injury. [ABSTRACT FROM AUTHOR]

[Display omitted] • The results of two experiments in the heating and cooling processes were consistent. • A model for apparent activation energy was established with carbon monoxide. • A lower oxygen concentration promoted coal to capture oxygen actively. • A method of unit flow of oxygen consumption was proposed. • The monitoring of index gas in cooling process is more important. In order to explore the changes during the coal cooling process in a closed fire zone (CFZ), the oxidation characteristics of the heating and cooling processes were thoroughly examined and compared. The heating and cooling processes under various oxygen concentrations of three coals were simulated with temperature-programmed experiment and coal spontaneous combustion experiment. Furthermore, the hottest spot, oxygen consumption, index gases, and oxidation kinetics between the gaseous production rate (f) and coal temperature (T), air supply (Q), oxygen concentration (C O 2), and apparent activation energy (E a) were analysed. The results revealed that the movements of the hottest spots did not overlap in the heating and cooling processes. Moreover, the oxygen consumption during the cooling process was higher than that during the heating process, and a lower oxygen concentration was associated with higher oxygen consumption, a condition in which coal strongly captured oxygen actively. The index gases during the heating and cooling processes notably differed, which were related to coal types, and during the forced heating process, the CO 2 /CO ratios of 1/3 coking coal and anthracite were higher than that of the forced cooling process, even under the oxygen-lean conditions, the CH 4 /C 2 H 4 ratio of lignite during the forced cooling process was also notable. Moreover, the results in the cooling process of the temperature-programmed experiment in the carrier gases with 7% and 3% O 2 were consistent with that of the spontaneous combustion experiment. Finally, the apparent activation energy at different stages of the heating and cooling processes was calculated, exhibiting inconformity, and apparent activation energy is lower in the cooling process, which is related to its higher oxygen consumption, and showing stronger oxidisability in the cooling process. In addition, through the results of coal oxidation kinetics, it is found that coal temperature affected the magnitude of apparent activation energy, the oxygen concentration impacted the oxidation activity of coal. These research results are valuable for informing the process of fire extinguishment and guiding the fire area unsealing in CFZ. [ABSTRACT FROM AUTHOR]

Abstract: Ethnopharmacological relevance: Ramulus Mori, the branch of Morus alba, is widely used in traditional Chinese medicine prescriptions to treat gout and hyperuricemia. Aim of this study: To evaluate the uricosuric and nephroprotective effects of ethanol extract of Ramulus Mori (ERM) and explore its possible mechanisms in hyperuricemic mice. Materials and methods: HPLC analysis was employed to determine the main constituents. Hyperuricemia was induced by potassium oxonate (250mg/kg) in male mice. ERM (10, 20 and 40mg/kg) was orally administered to hyperuricemic and normal mice for 7 days. Serum and urine levels of uric acid, creatinine and blood urea nitrogen (BUN) were measured. Simultaneously, renal mRNA and protein levels of mouse urate transporter 1 (mURAT1), glucose transporter 9 (mGLUT9), organic anion transporter 1 (mOAT1) and organic cation/carnitine transporters (mOCT1/2, mOCTN1/2) were analyzed by RT-PCR and Western blotting methods. Results: ERM mainly contained mulberroside A, oxyresveratrol, 4-hydroxycinnamic acid, resveratrol, 7-hydroxycumarin and morin. ERM significantly reduced serum urate levels and increased 24h-urine urate excretion and fractional excretion of uric acid in hyperuricemic mice. It effectively restored oxonate-induced expression alteration of renal mURAT1, mGLUT9 and mOAT1, resulting in urate excretion enhancement. Moreover, ERM decreased serum creatinine and BUN levels and increased creatinine clearance, and up-regulated expression of mOCT1/2 and mOCTN1/2, contributing to kidney function improvement in this model. Conclusion: These results suggest that ERM exerts the uricosuric and nephroprotective actions by the regulation of these renal organic ion transporters in hyperuricemic mice, and provide scientific support for the empirical use of Ramulus Mori. [Copyright &y& Elsevier]

Ethnopharmacological relevance: Sanmiao wan (SMW) is widely used for the treatment of gout and hyperuricemia in traditional Chinese medicine. Aim of the study: The aim of the present study was to investigate the hypouricemic effects of SMW and its possible mechanism in potassium oxonate-induced hyperuricemic mice. Materials and methods: SMW at 489, 978 and 1956mg/kg was orally administered to hyperuricemic and normal mice, and standard drug allopurinol (2.5mg/kg) was served as a positive control. The effects of SMW on serum, urine and liver levels of uric acid, serum levels of creatinine, and activity of hepatic xanthine oxidase (XOD) were measured in mice. Moreover, the effects of SMW on the mRNA and protein levels of hepatic XOD and renal urate transporter 1 (mURAT1) in mice were analyzed by semi-quantitative RT-PCR and Western blotting methods, respectively. Results: SMW significantly reduced uric acid levels in serum and liver, inhibited hepatic XOD activity, mRNA and protein levels in hyperuricemic mice. Furthermore, SMW could effectively down-regulate renal mURAT1 mRNA and protein levels of hyperuricemic mice. And it reversed oxonate-induced elevation in serum creatinine levels of mice. However, SMW did not show any effects in normal mice. Conclusion: These findings suggested that SMW produced dual hypouricemic actions by suppressing hepatic XOD to reduce uric acid production and down-regulating renal mURAT1 to decrease urate reabsorption and enhance urate excretion in hyperuricemic mice. [Copyright &y& Elsevier]

[Display omitted] • The indicator gas analysis method was substantially improved. • The principle diagram of the low-temperature oxidation process of coal was drawn. • The actual exothermic strengths of the coal samples were compared. • The effect of the coal metamorphic degree on spontaneous combustion was determined. To investigate the effect of coal metamorphism on the probability of coal spontaneous combustion (CSC), five types of coal sample were subjected to a temperature-programmed testing system. The gas indicators and limiting parameters of CSC were analysed and the characteristics of different ranks of coal were observed during low-temperature oxidation. The CO production rate of each coal sample was positively correlated with temperature and the CO production rate of low-ranked coal was greater than that of high-ranked coal. The CO/O 2 and CO productivity trends were the same. Analysis of the change in the alkene ratio revealed that the oxidation reaction became more intense if the coal temperature exceeded the dry cracking temperature. The oxygen consumption rate of each coal sample was positively correlated with temperature, low-ranked coal samples exhibiting higher oxygen consumption rates. Graham's fire coefficient can be used as an auxiliary gas indicator to judge CSC tendency. Analysis of the limiting parameters of CSC revealed that the low limiting oxygen volume fraction and the minimal thickness of residual coal of high-rank samples were higher, whereas maximal air leakage intensity was lower. This paper further demonstrated differences in CSC tendency depending on the coal rank. These findings clarified certain factors affecting CSC, which may aid in preventing CSC in the future. [ABSTRACT FROM AUTHOR]

The chemical structure and morphological of lignite treated with four imidazole ionic liquids (ILs), namely [BMIM][BF 4 , [BMIM][NO 3 , [BMIM][I], and [EMIM][BF 4 , was characterized through scanning electron microscopy and X-ray diffraction. Furthermore, the exothermic properties of the oxidation process at low temperatures (<200.0 °C) were investigated using a C80 microcalorimeter. The results revealed that the IL partially dissolved minerals and side chains of surface molecules in lignite, resulting in reduction of the unit stacking degree, ductility, and number of effective piles, which ultimately led to a lower coalification degree of the treated coal sample. The initial exothermic temperature of the treated coal sample increased and that more thermal energy was absorbed and less thermal energy was released in the endothermic and exothermic phases, respectively, as a result of the destruction of the molecular structure of coal by IL. The exotherm and the exothermic heat release rates from treated coal samples were consistent and in the following order: IL-untc > [BMIM][NO 3 -tc > [BMIM][I]-tc > [EMIM][BF 4 -tc > [BMIM][BF 4 -tc. The IL destroys the chemical structure of the coal, resulting in a decrease in the activity of the coal, which is manifested by an increase in apparent activation energy. • A new initial temperature characterization method was established. • The external morphology and structure of coal have changed due to ILs. • ILs have a prominent effect of reducing on the exothermic properties. • The oxidation activity of coal could be feasibly inert by ILs. [ABSTRACT FROM AUTHOR]

• Volatiles variations were inversely related with changes of fixed carbon. • A factor analysis method combining qualitative and quantitative was proposed. • Heat transfer mechanism of coal low temperature oxidation process was investigated. • Correlation between thermal properties and proximate analysis was approached. The low temperature oxidation of coal is a contradictory and unified dynamic process of coexisting mass and heat transfer. The thermophysical properties are crucial during coal spontaneous combustion. In the current paper, the variations of moisture, ash, volatiles, fixed carbon and thermophysical properties (thermal diffusivity, specific heat and thermal conductivity) of three coal samples from 30 °C to 300 °C were studied, and their grey correlation was analyzed. The results indicated that with the increase of temperature, the free moisture of Coals A and B decreased first but then increased, while the free moisture of Coal C kept decreasing without a later increase. The variation of surface moisture was consistent with that of free moisture. The trend of volatiles and fixed carbon was completely the opposite, showing a significant negative correlation. Ash was less affected by temperature. Along with the rise of temperature, the thermal diffusivity of three coal samples decreased first but later increased, and the specific heat was always in a state of increasing. The change in thermal conductivity was mainly affected by specific heat. By calculating the grey correlation degree, the major factors affecting the thermophysical properties were obtained. [ABSTRACT FROM AUTHOR]

To accomplish various and efficient inhibitions of coal spontaneous combustion (CSC) and solve the safety hazards of CSC encountered in the production and operation of coal mining enterprises, inhibitors play an important role in the prevention and management of CSC. Herein, we report quercetin, which is selection as an antioxidant to prepare a composite solid lipid inhibitor. The concentration of the composite solid lipid inhibitor with the best inhibition effect on the active groups is selected by Fourier pressure infrared experiments, the change pattern of gas content and characteristic temperature released from coal samples during an oxidation process warming process was tested by using a programmed warming test system and simultaneous thermal analysis experiments, and finally, the inhibitory rate and combustion characteristic index were calculated. The results of the research showed that 10 mass% of quercetin had the most impact on the various groups, the highest inhibitor rate of the composite solid lipid inhibitor is 80.67% in the coal low-temperature oxidation process, compared to the raw coal, the heat release of coal treated with the composite solid lipid inhibitor was decreased by 507.65 J g−1, the maximum amount of heat emitted was lowered by 60%, and the flammability index was reduced by 56.4. A composite solid lipid inhibitor containing quercetin developed in this paper indicated high effectiveness in inhibiting CSC, which is vital for coping with the safety management of coal mine production. [ABSTRACT FROM AUTHOR]

This work investigated the ignition and flame spreading features over an excessively overloaded wire coated with polyvinyl chloride (PVC) to provide valuable information for determining fire behavior caused by this typical type of wire failure. The wires with a core/wire diameter of 3.3/4.1 mm carried various overload currents from 130 A to 240 A at intervals of 10 A. Experimental results revealed that occurrence of a parting arc as the core melted into two parts was indispensable for ignition of the overloaded PVC wire without an external ignition source. The current increase reduced the time for energizing the wire to a parting arc. For this special piloted flame, with the current increase, the intensity of the heating of the core became higher; thus, the flame spread distance (FSD) became longer due to the thermal decomposition of the PVC insulation intensifying, and the average flame spread rate reached its maximum value of approximately 1.0 m/s as the current increased to 220 A. However, the FSD declined as the currents reached higher than 220 A because the faulting wire melted so quickly that it did not have enough time for the insulation materials to decompose and produce sufficient flammable gases. [ABSTRACT FROM AUTHOR]

• Pyrolytic behavior differs significantly with different degrees of thermal aging. • Thermal aging leads to more easily pyrolysis of cables. • Different degrees of thermal aging have little effect on the pyrolysis mechanism. • The most dangerous threshold for the pyrolysis of ZR-BVR is aging for 20 days. Thermal aging produces irreversible aging to home decoration PVC insulation copper cables through high temperatures, and their pyrolytic behavior changes as a result. The thermogravimetric-Fourier transform infrared analysis, the model-free method and the Málek method were used to investigate the effect of thermal aging on the pyrolysis mechanism of domestic PVC insulation copper cables. It was found that pyrolysis is more easily to occur in aged cables, and 20 days of aging is the most dangerous threshold for the pyrolysis of ZR-BVR cable insulation. The pyrolysis release gases were mainly concentrated in the temperature intervals of 270-340 and 400-700°C. In addition, it should be noted that different degrees of thermal aging affect the pyrolysis behavior of cable insulation but have little effect on the pyrolysis mechanism. [ABSTRACT FROM AUTHOR]

• Mechanisms causing mass variation of combusting coal were separated and evaluated. • Contributions of different mechanisms to mass variation of coal were researched. • Transformation of the kinetic mode in spontaneous coal combustion was explored. • Kinetic compensation effect of variations in E a and A was investigated. Coal spontaneous combustion (CSC) is a severe threat to coal mining operations. Using thermogravimetric experiments, the contributions of different mechanisms to the mass variation during CSC were analysed. Furthermore, the kinetic mode and kinetic compensation processes were investigated. Among the different mechanisms of coal–oxygen reaction, solid-phase combustion contributes least to mass loss; for coals of high rank, gas-phase combustion makes the greatest contribution. Oxidative decomposition contributes most for coals of low rank. Furthermore, the kinetic mode governing CSC is three-dimensional diffusion in the mass gain stage and changes to random nucleation and subsequent growth in the mass loss stage. The apparent activation energy reaches its maximum near the ignition temperature and indicates a kinetic compensation effect with the pre-exponential factor in each stage. These findings are crucial for understanding the processes involved in CSC. [ABSTRACT FROM AUTHOR]

The coalfield fire is determined by fractures of coal and rock that provide tunnel for gases and heat exchange. To study fracture propagation at high temperatures, high-resolution X-ray computed tomography (CT) was used to scan anthracite and mudstone samples collected from the Qinshui coalfield, Shanxi Province, northern China. The samples were scanned at 100 °C intervals as they were subjected to temperatures of up to 500 °C. Three-dimensional images were reconstructed by the CT software to analyze changes in the fractures and pores in the samples. The experimental results show that fracturing of anthracite began at 200 °C. The generation rate of fractures in the coal samples increases slowly below 300 °C, but above 300 °C there is a sharp increase in fracture development. This indicates that the thermal fracturing temperature threshold for anthracite is 300 °C. During the experiment, it was found that preexisting fractures, voids, and regenerative fractures formed around the hard portions of anthracite particles or along the weak boundaries between particles. Some regenerative fractures developed along the fabric of the relatively crystalline particles within the particle and terminate at the edge of the particle or where the fracture encounters a harder portion of coal. Some fractures even expanded enough to be transformed into voids as temperatures rose. In the mudstone, the porosity changed suddenly at 300 °C. This indicated that there was a void generated at 200 °C, but the void expanded when the temperature was increased. However, changes in the void were not obvious from 200 to 300 °C. [ABSTRACT FROM AUTHOR]

Coal spontaneous combustion (CSC) is a global, long-standing thermal hazard in coal mining that causes serious environmental damage, particularly in developing countries. Ionic liquids (ILs) are environmentally friendly, green, economical, and a new type of fire-preventing material that inhibits coal oxidation and alleviates thermal production. In this study, 1-butyl-3-methyl imidazole tetrafluoroborate ([BMIM][BF4]) and 1-butyl-3-methyl imidazole ([BMIM][I]) at various mass ratios (0.0, 0.5, 2.0, 5.0, and 10.0 mass%) were used to treat three types of coal (lignite, 1/3 coking coal, and anthracite) for CSC. The combustion-mass loss and thermal release rate of ILs treated relative to untreated coal samples were investigated using a synchronous thermal analyzer, and the optimal addition mass ratio of ILs was predicted. Not only do ILs have the most efficient inhibiting effect, but they also consider the economic benefit. Per thermogravimetric-differential scanning calorimetry, for the content of 5.0 mass% [BMIM][BF4], the inhibiting effect is favorable for universal applications. In addition, coal samples treated with 5.0 mass% [BMIM][BF4] were subjected to programmed-temperature heating experiment testing. The oxygen consumption rate, inhibiting effect, as well as apparent activation energy, were determined. The inhibiting effect at 120.0–150.0 °C was the most obvious, which provided the basis of the application for CSC prevention. [ABSTRACT FROM AUTHOR]

As a non-precious catalyst for the electrochemical hydrogen evolution reaction (HER), the two-dimensional MoS 2 has been widely studied. To activate the MoS 2 inert basal plane to enable optimal activity, high defect concentration of sulfur vacancies is needed. Herein, based on the first-principles calculations we demonstrate that the HER of MoS 2 can be greatly enhanced by As doping and biaxial strain. We show that the As-doping sites are new catalytic sites and the bonding of H can be greatly enhanced. Moreover, the relative hydrogen adsorption free energy (Δ Δ G H) can be further manipulated by the strain effect, which efficiently adjusts the catalytic activity. With the synergy of the biaxial strain (2%–3%) and the uniform doping of the As atoms (3.125% concentration), the Δ Δ G H can be modulated to zero. Our findings provide a way to achieve the high intrinsic HER activity among molybdenum-sulfide-based catalysts. • Hydrogen revolution energy (HER) of MoS 2 can be greatly enhanced by 3.125% As doping. • A small biaxial stain can further tune the HER perfomance of As-doped MoS 2. [ABSTRACT FROM AUTHOR]

Heat transfer in a coal mass is governed by thermophysical properties such as thermal diffusivity, specific heat capacity, and thermal conductivity. Coal samples were preoxidized at 90, 150, and 200 °C in a temperature-programmed oxidation apparatus, with raw coal acting as the control group. A laser flash method was employed to examine the thermophysical properties of the coal samples and establish a relationship between the thermophysical properties and the coal's microcrystalline structure/pore structure. The results indicated that thermal diffusivity decreased and specific heat capacity and thermal conductivity raised when the temperature increased. Furthermore, when the preoxidation temperature increased, aromatic microcrystalline structures developed and the specific surface area of the coal samples first decreased and then increased. Moreover, thermal diffusivity and thermal conductivity increased with the elevated preoxidation temperature, and specific heat capacity was the highest at 90 °C. The reason for this was that preoxidation of the coal samples influenced the development of aromatic microcrystalline structures and pore structures, promoting the heat transfer on coal mass. [ABSTRACT FROM AUTHOR]

Abstract This study examined the combustion characteristics and kinetics of coal samples treated with imidazole-based ionic liquids (ILs), namely, [Emim][BF 4 ], [Bmim][BF 4 ], [Bmim][NO 3 ], and [Bmim][I], under oxidation. The oxidation of the coal samples was investigated using thermogravimetry (TG) at heating rates of 4.0, 6.0, 8.0, and 10.0 °C·min−1. The results for the IL-treated samples revealed that the composite index S (representing the ignition, combustion, and burnout properties) decreased and H f (representing the rate and intensity of the combustion process) increased with high correlation coefficients. The characteristic temperatures of the maximum oxidization mass gain (T 2), ignition point (T 3), maximum mass loss rate (T 4), and burnout point (T 5) increased by 13.1 ± 0.5, 9.2 ± 0.5, 21.5 ± 0.5, and 35.9 ± 0.5 °C, respectively. At T 3 and the maximum mass loss rate, the release of CO and CO 2 was further altered, suggesting that the C O functional groups were damaged or oxidized. The results of the Ozawa-Flynn-Wall kinetic equation used to determine the apparent activation energy (E a) of coal samples revealed that the E a of the treated samples increased. The reaction rate constant characterizes the effect of E a and pre-exponential factors (A), and the results showed that ILs can weaken the reaction process at low temperatures (<130 °C). Highlights • Changes in the combustion performance occurred in samples treated with ILs. • The S decreased and H f increased with an increase in the amount of ash. • The reaction process of the treated sample is accelerated above 130 °C determined by k. • The difference in gas reveals that C O was destroyed by ILs. [ABSTRACT FROM AUTHOR]

Coal spontaneous combustion occurs frequently in mining and utilizing processes, which mostly result from the complex dynamic reaction of coal and oxygen. With a focus on the mass gain phenomenon of coal oxidation observed by thermogravimetric analysis, TG-FTIR and in situ IR experiments for a typical Jurassic coal in West China were carried out to identify the kinetics and mechanisms of coal oxidation. The results showed that a mass loss existed both in coal oxidation and pyrolysis process, but the phenomenon of mass gain was particular in coal oxidation process. By FTIR analysis, CO and CO2 produced in the oxidation process were more than those in the pyrolysis process. By Ozawa method, the apparent activation energy at the initial temperature of mass gain stage was determined to be 43.17 kJ mol−1, which was much less than that at the end temperature of 122.0 kJ mol−1. With in situ IR analysis of Liangshuijing coal during the oxidation and pyrolysis process, the oxidation mass gain mechanism was discussed. It was concluded that the key functional groups for this typical coal oxidation mass gain were carboxyl and carbonyl. [ABSTRACT FROM AUTHOR]

Toll-like receptor 4 (TLR4) and C5aR1 (CD88) have been recognized as potential therapeutic targets for the reduction of inflammation and secondary damage and improvement of outcome after ischemia and reperfusion (I/R). The inflammatory responses which induce cell apoptosis and necrosis after I/R brain injury lead to a limited process of neural repair. To further comprehend how these targets function in I/R state, we investigated the pathological changes and TLR4 and C5aR1 signaling pathways in vitro and in vivo models of I/R brain injury in this study. Meanwhile, we explored the roles of schisantherin A on I/R brain injury, and whether it exerted neuroprotective effects by regulating the TLR4 and C5aR1 signaling pathways or not. The results showed that schisantherin A significantly reduced the neuronal apoptosis induced by oxygen and glucose deprivation and reperfusion (OGD/R) injury in primary culture of rat cortical neurons. Also, schisantherin A alleviated neurological deficits, reduced infarct volume, attenuated oxidation stress, inflammation and apoptosis in ischemic parietal cortex of rats after middle cerebral artery occlusion and reperfusion (MCAO/R) injury. Moreover, the activated TLR4 and C5aR1 signaling pathways were inhibited by schisantherin A treatment. In conclusion, TLR4 and C5aR1 played a vital role during I/R brain injury in rats, and schisantherin A exhibited neuroprotective effects by TLR4 and C5aR1 signaling pathways. These findings also provided new insights that would aid in elucidating the effect of schisantherin A against cerebral I/R and support the development of schisantherin A as a potential treatment for ischemic stroke. [ABSTRACT FROM AUTHOR]

Among coal-producing countries, China has witnessed the highest frequency and severity of coal fires. During mining in the re-mining face and the lower part of the thick coal seam (or coal seam group), second or multiple oxidations of the residual coal can readily occur in mined-out areas, severely increasing the risk of coal fires. The study of multiple oxidations of coal aids in the early detection of spontaneous combustion of remaining coal in the mined-out areas. The characteristics of coal fires are demonstrated using fresh coal samples (first-oxidized coal) and oxidized coal samples (second-oxidized coal) from four different ranks of coals. Proximate and elemental analysis, Fourier transform spectroscopy, and thermogravimetry-differential scanning calorimetry were adopted to investigate the quality, microcharacteristics, characteristic temperatures, and apparent activation energy of second-oxidized coal. In addition, the effect of spontaneous combustion at heating rates of 5.0, 10.0, and 15.0 °C min was studied. Compared with the four samples of first-oxidized coal, those of second-oxidized coals cause fire easily under the same conditions. [ABSTRACT FROM AUTHOR]

• Variation in sound absorption is studied based on the structural properties of coal. • Sound waves mainly propagate along the voids in loose coal. • Loose coal belongs to the high absorption medium of sound waves. • The obtained peak frequency provides basis for the selection of the acoustic signal. With the advantages of high applicability and reliability, the acoustic detection method has been widely used in the field of temperature measurement, positioning, and flaw detection. To apply acoustic temperature measurement techniques to the detection of high temperature points of loose coal spontaneous combustion, the basic acoustic properties of loose coal need to be clarified. Four bituminous coals with different degrees of metamorphosis were selected for the study. The stacking structural characteristics of loose coal were studied by industrial computerized tomography. The sound absorption coefficient of loose coal was tested based on the sound absorption test system. The results revealed that with the increase of particle size, the voids of loose coal gradually became larger and the connectivity became better. The distribution characteristics of voids in loose coal were intrinsic to the variation in sound absorption coefficients. The sound absorption coefficient was more influenced by the particle size and stack thickness than by the degree of deterioration. Except for the particle size of less than 0.9 mm and the stacked thickness of 2 cm coal samples, the absorption coefficients of the coal samples increased gradually with decreasing particle size at the same acoustic frequency, and the peak absorption coefficients gradually shifted towards lower frequencies with increasing thickness. The peak frequency range of the absorption coefficient was calculated to provide a basis for the selection of the frequency band of the acoustic temperature measurement signal for loose coal. [ABSTRACT FROM AUTHOR]

To contain coal fires, three green antioxidants of plant extract which cover resveratrol (Res), tea polyphenols (TP), and β -carotene (β -car) are investigated in this paper, and their inhibitory effects on surface groups and structure are revealed. X-ray diffraction test tells that antioxidants exert a slight augment of d 100 and L c and are able to destroy the unstable side chains to some extent. Though coal samples are affected by antioxidants, minimal differences of aromatic structure have been proved. Fourier-transform infrared spectroscopy technique is employed and a new concept of influence sensitivity value is introduced. The results indicate that antioxidants and addition amounts have an impact on various groups, and the majority of groups tend to be inhibited within 3 wt% addition. Further, the optimal inhibitory concentration of Res, TP, and β -car is 1 wt%, 3 wt%, and 1 wt%, respectively. Combined with gaseous indexes, CO 2 emissions of Res and TP exhibit a wave variation under 100 °C, and exponential growths of others occurred twice is acquired. Antioxidants can bring out the decline of apparent activation energy (E a), and TP worked most brilliantly and it increases E a by 7.503 kJ/mol. In summary, the order of inhibitory effect is TP > Res > β -car. • Antioxidants have a slight effect on microcrystalline structure. • A new definition is introduced to explain the groups' variation. • The best inhibitory effect of antioxidants is addition of 1 wt% or 3 wt%. • Inhibitory effect contains a complex action of physics and chemistry probably. [ABSTRACT FROM AUTHOR]

• Correlation between gas products and active groups is determined for CDDM. • Relationship between active groups and exothermic is characterized for CDDM. • Evolution difference of active groups is explored for CDDM. • Oxidizing ability of active groups determine macroscopic characteristics of coal. The exothermic kinetic properties of the oxidation of key active groups are closely related to the coal with different degrees of metamorphism (CDDM) in the low-temperature oxidation of coal. To study the dynamic characteristics of oxidative exotherm of the key active groups for the CDDM, and reveal the macroscopic and microscopic interrelationships, the CDDM were selected and analyzed through temperature-programmed testing system, microcalorimetry experimental system, and in-situ Fourier transform infrared spectrometer experimental system. The results indicated that the carbonyl groups were oxidized to produce CO and CO 2 at an increased rate in the accelerated oxidation stage. In the vigorous oxidation stage, the accumulation of heat accelerated the conversion of methyl and methylene groups to carbonyl groups, and promoted the oxidation reaction. At the same temperature conditions, the total production of CO and CO 2 released from a coal with a high degree of metamorphism is lower. The key preventing the low-temperature oxidation is obstructing the reaction progression of the accelerated oxidation stage and the carbonyl groups, which are the key stage and active groups respectively. [ABSTRACT FROM AUTHOR]

Abstract: Honokiol and magnolol are the main constituents simultaneously identified in the barks of Magnolia officinalis, which have been used in traditional Chinese medicine to treat a variety of mental disorders including depression. In the present study, we reported on the antidepressant-like effects of oral administration of the mixture of honokiol and magnolol in well-validated models of depression in rodents: forced swimming test (FST), tail suspension test (TST) and chronic mild stress (CMS) model. The mixture of honokiol and magnolol significantly decreased immobility time in the mouse FST and TST, and reversed CMS-induced reduction in sucrose consumption to prevent anhedonia in rats. However, this mixture was unable to affect ambulatory or rearing behavior in the mouse open-field test. CMS induced alterations in 5-hydroxytryptamine (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) levels in various brain regions of rats. An increase in serum corticosterone concentrations and a reduction in platelet adenylyl cyclase (AC) activity were simultaneously found in the CMS rats. The mixture of honokiol and magnolol at 20 and 40 mg/kg significantly attenuated CMS-induced decreases of 5-HT levels in frontal cortex, hippocampus, striatum, hypothalamus and nucleus accumbens. And it markedly increased 5-HIAA levels in frontal cortex, striatum and nucleus accumbens at 40 mg/kg and in frontal cortex at 20 mg/kg in the CMS rats. A subsequent reduction in 5-HIAA/5-HT ratio was found in hippocampus and nucleus accumbens in the CMS rats receiving this mixture. Furthermore, the mixture of honokiol and magnolol reduced elevated corticosterone concentrations in serum to normalize the hypothalamic–pituitary–adrenal (HPA) hyperactivity in the CMS rats. It also reversed CMS-induced reduction in platelet AC activity, via upregulating the cyclic adenosine monophosphate (cAMP) pathway. These results suggested that the mixture of honokiol and magnolol possessed potent antidepressant-like properties in behaviors involved in normalization of biochemical abnormalities in brain 5-HT and 5-HIAA, serum corticosterone levels and platelet AC activity in the CMS rats. Our findings could provide a basis for examining directly the interaction of the serotonergic system, the HPA axis and AC-cAMP pathway underlying the link between depression and treatment with the mixture of honokiol and magnolol. [Copyright &y& Elsevier]