In this paper, we propose high-order interface-penalty finite element methods for elasticity interface problems in three dimensions. Optimal error estimates are proven in energy norms for ...interface-penalty finite element methods. The error estimates are independent of the cut configurations. A series of three-dimensional numerical results confirm the efficiency of the proposed methods.
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•The co-spontaneous combustion process of coal and gangue is investigated.•The interaction of coal and gangue is affected by microstructure and reaction stage.•Promotion dominates the ...co-spontaneous combustion process of coal and gangue.•Co-combustion stage of mixtures of coal and gangue follows order reaction.•The Cb is greatly affected by gangue content while the Sc depends more on coal.
The co-spontaneous combustion of coal and gangue widely exists in the world and threatens the safety of coal mines. In this paper, the microstructure of coal and gangue were tested and the thermal behavior during the co-spontaneous combustion process of coal and gangue with different mass ratios were investigated by using synchronous thermal analyzer, and the combustion characteristic indices and kinetic parameters were calculated. The results indicated the carbon content of gangue is much lower than that of coal, but the content of oxygen-containing functional groups and sulfides in gangue are far higher than that in coal. Moreover, gangue possesses more developed pores and specific surface area. With the increase of coal mass fraction, the combustion index of ignition of mixed samples increases linearly, while the combustion index of burnout and synthetical combustion grows exponentially. The mixtures of coal and gangue follows the interfacial reaction at the oxygen adsorption stage and the order reaction at the moisture evaporation and combustion stages. The practical apparent activation energy at the moisture evaporation and combustion stages is higher than the theoretical value. However, it shows the opposite result at the oxygen adsorption stage. Coal and gangue inhibit each other at the moisture evaporation and later combustion stages, but promote each other at the oxygen adsorption and earlier combustion stages. On the whole, the co-spontaneous combustion process of coal and gangue is dominated by promotion. As a result, the practical values of mass loss and heat release in the whole reaction process are greater than the theoretical ones. Therefore, the danger of spontaneous combustion is higher when coal and gangue coexist.
Owing to the development of nanotechnology and noninvasive treatment, thermal therapy in combination with external stimuli has been applied for tissue engineering and regenerative medicine (TERM), ...which has attracted more and more attention in recent years. In this review, the recent progress of applying a variety of non‐invasive thermal therapeutic modalities for TERM, including photothermal therapy, magnetic thermotherapy, and ultrasound thermotherapy, as well as other thermal therapeutics are discussed. The parameters and conditions that need to be considered and regulated to realize a well‐controlled thermal therapy for tissue regeneration are also discussed. Afterwards, the current concerns and challenges of putting thermal therapy into clinical applications are pointed out. At last, perspectives are provided for the future development directions, aiming to providing opportunities and a novel pathway for TERM.
Owing to the development of nanotechnology and non‐invasive treatment, thermal therapy in combination with external stimuli has been applied for tissue engineering and regenerative medicine, which has attracted more and more attention in recent years. Among them, photothermal therapy, magnetic thermotherapy, and ultrasound thermotherapy show attractive charm due to their convenient regulation and precise thermal positioning.
Current photocatalytic semiconductors often have low catalytic performance due to limited light utilization and fast charge carrier recombination. Formation of Schottky junction between ...semiconductors and plasmonic metals can broaden the light absorption and facilitate the photon‐generated carriers separation. To further amplify the catalytic performance, herein, an asymmetric gold‐zinc oxide (Asy‐Au−ZnO) nanorod array is rationally designed, which realizes the synergy of piezocatalysis and photocatalysis, as well as spatially oriented electron−hole pairs separation, generating a significantly enhanced catalytic performance. In addition to conventional properties from noble metal/semiconductor Schottky junction, the rationally designed heterostructure has several additional advantages: 1) The piezoelectric ZnO under light and mechanical stress can directly generate charge carriers; 2) the Schottky barrier can be reduced by ZnO piezopotential to enhance the injection efficiency of hot electrons from Au nanoparticles to ZnO; 3) the unique asymmetric nanorod array structure can achieve a spatially directed separation and migration of the photon‐generated carriers. When ultrasound and all‐spectrum light irradiation are exerted simultaneously, the Asy‐Au−ZnO reaches the highest catalytic efficiency of 95% in 75 min for dye degradation. It paves a new pathway for designing unique asymmetric nanostructures with the synergy of photocatalysis and piezocatalysis.
An asymmetric Au−ZnO nanorod array is developed for efficient separation of photon‐generated charge carriers with assistance of piezophototronic effect. The unique asymmetric structure can significantly enhance the spatially directed migration and separation of the photon‐generated carriers with assistance of piezophototronic effect, and further realize enhanced catalytic activity by the synergy of piezocatalysis and photocatalysis.
The low loading rate of the thin coal seam shearer drum is a severe obstacle to the efficient mining of thin seam resources, and the auxiliary drum loading through the cowl is an effective measure to ...alleviate this situation. However, the working mechanism of the coal cowl still remains unclear. In this paper, with the help of the discrete element method and the modeling experiment method, the effects of coal cowl's offset distance, tilt angle and wrap angle on the coal loading rate under different loading modes of the drum are investigated; and the significance of various factors and their interactions to the drum coal loading rate is explored by designing response surface experiments. The findings show that a monotonous negative correlation between the offset distance of the coal cowl and the coal loading rate is identified, and that a smaller offset distance can effectively improve the coal loading rate of the drum. The conveying torque is significantly increased, easily inducing the drum choking, coal recycling coal over-crushing. Along with the increasing tilt angle, the rate of ejection loading decreases monotonically, and the rate of pushing loading increases first and then decreases. Coal loading rate is weakly affected by changes in coal cowl's wrap angle. The results of response surface analysis reveal that the most significant factors affecting the drum's coal loading rate are tilt angle and offset distance in ejection and pushing loading modes, respectively. The conclusions drawn here offer implications for improving the coal loading performance of the thin coal seam shearer drum, as well as certain guidance on the optimal design of coal cowl parameters.
With the increasingly severe damage wreaked by forest fires, their scientific and effective prevention and control has attracted the attention of countries worldwide. The breakthrough of remote ...sensing technologies implemented in the monitoring of fire spread and early warning has become the development direction for their prevention and control. However, a single remote sensing data collection point cannot simultaneously meet the temporal and spatial resolution requirements of fire spread monitoring. This can significantly affect the efficiency and timeliness of fire spread monitoring. This article focuses on the mountain fires that occurred in Muli County, on 28 March 2020, and in Jingjiu Township on 30 March 2020, in Liangshan Prefecture, Sichuan Province, as its research objects. Multi-source satellite remote sensing image data from Planet, Sentinel-2, MODIS, GF-1, GF-4, and Landsat-8 were used for fire monitoring. The spread of the fire time series was effectively and quickly obtained using the remote sensing data at various times. Fireline information and fire severity were extracted based on the calculated differenced normalized burn ratio (dNBR). This study collected the meteorological, terrain, combustibles, and human factors related to the fire. The random forest algorithm analyzed the collected data and identified the main factors, with their order of importance, that affected the spread of the two selected forest fires in Sichuan Province. Finally, the vegetation coverage before and after the fire was calculated, and the relationship between the vegetation coverage and the fire severity was analyzed. The results showed that the multi-source satellite remote sensing images can be utilized and implemented for time-evolving forest fires, enabling forest managers and firefighting agencies to plan improved firefighting actions in a timely manner and increase the effectiveness of firefighting strategies. For the forest fires in Sichuan Province studied here, the meteorological factors had the most significant impact on their spread compared with other forest fire factors. Among all variables, relative humidity was the most crucial factor affecting the spread of forest fires. The linear regression results showed that the vegetation coverage and dNBR were significantly correlated before and after the fire. The vegetation coverage recovery effects were different in the fire burned areas depending on fire severity. High vegetation recovery was associated with low-intensity burned areas. By combining the remote sensing data obtained by multi-source remote sensing satellites, accurate and macro dynamic monitoring and quantitative analysis of wildfires can be carried out. The study’s results provide effective information on the fires in Sichuan Province and can be used as a technical reference for fire spread monitoring and analysis through remote sensing, enabling accelerated emergency responses.
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•Electrospun quad-axial nanofibers can be fabricated by quadriaxial electrospinning.•The quad-axial configuration of the nanofibers can improve the functionality.•Drugs can be ...encapsulated in the different layers of quad-axial nanofibers.
It is of great importance and a major challenge to achieve a controlled delivery of specific types of active ingredients for tissue regeneration. Herein, we report a system comprised of electrospun quad-axial nanofibers fabricated by quadriaxial electrospinning, with the material components in the different layers can be well regulated. The quad-axial nanofibers allow the regulation of the type of materials in different layers as well as the manipulation of the location of drug in the nanofibers, representing a promising controlled drug release system. In one typical example, we apply polycaprolactone to construct both the outermost and second innermost layers while gelatin to construct both the second outermost and innermost layers. The nanofibers with a cleared four-layered nanostructure are confirmed by morphological evaluations. Moxifloxacin, a type of antibacterial drug serving as a model of therapeutic payload, is encapsulated in the different layers of the nanofibers, realizing an effective control of the drug delivery. In addition, the efficacy for drug delivery with the use of quad-axial nanofibers is superior to that of core-sheath and blended nanofibers. This quadriaxial electrospinning technique can be widely used for the co-delivery of factor cocktails in a designed sequence, which will show great potential for tissue engineering.
In this work, a WS2 nanosheet/graphite microfiber hybrid electrode has been fabricated by in situ synthesis of WS2 nanosheets on the surface of graphite microfibers. The WS2 nanosheets possess an ...excellent electrocatalytic oxidation response towards adenine and guanine that encourages the adsorption of nucleobases and charge transfer at the surface of the microfibers. The WS2 nanosheet/graphite microfiber hybrid electrode shows high sensitivity and selectivity for the detection of adenine and guanine. This hybrid microfiber electrode represents an excellent candidate platform for development of an electrochemical biosensor due to its low cost, flexibility and 3D morphology.
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•A WS2 nanosheet/graphite microfiber hybrid structure was synthesized in situ.•For the first time, WS2 nanosheets were used to electrocatalyze adenine and guanine.•The microfiber hybrid electrode can be used to detect adenine and guanine, exhibiting excellent detection sensitivity, selectivity and stability.•This approach can be extended to the design of other molecular biosensors.
The immune system plays an essential role in protecting the body against pathogens. Immune cells are activated during infections, resulting in a metabolic shift from oxidative phosphorylation to ...glycolysis. During glycolysis, methylglyoxal (MGO) can be formed as a by-product. As a highly reactive dicarbonyl compound, MGO can rapidly react with proteins to form advanced glycation end products (AGEs). MGO and MGO-derived AGEs have been implicated in the development of insulin resistance, type 2 diabetes and its complications and several other age-related inflammatory diseases. MGO has been found in adipose tissue, atherosclerosis plaques and inflamed livers. Aside from the potential harmful role of MGO, there are studies showing beneficial effects of MGO as a defense mechanism during infections and diseases. In this review, we summarize anti-microbial effects of MGO and the link between MGO and immune cell activation, as potential mediator during host defense.
•Immune cell activation is associated with enhanced glycolysis, leading to the formation of the reactive dicarbonyl methylglyoxal (MGO).•MGO rapidly leads to the formation of protein adducts and is cytotoxic.•MGO has direct anti-microbial effects and immunomodulatory effects.•The extent of MGO production in immune cells and its contribution to host defense remain to be further elucidated.
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