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Abstract The application of biomass energy is one of the important ways to achieve carbon neutrality and deal with global warming. The study on the combustion mechanism of anisole, an oxygen-containing fuel, is helpful for biofuel large-scale application. In this study, the soot formation and laminar combustion characteristics of anisole were analyzed by reactive force field molecular dynamics (ReaxFF MD) and kinetic simulation, respectively. ReaxFF MD simulation studies had shown that soot formation of anisole combustion occurred in three stages, stage 1 (0–1 ns), stage 2 (1–2.5 ns), stage 3 (2.5–6 ns). The three stages represented the pyrolysis of the fuel, the developmental stage of the soot, and the graphitization stage of the soot, respectively. During the combustion of anisole, primary mechanisms for the soot formation were as follows: H-abstraction-C2H2-addition, carbon-addition-hydrogen-addition, internal ring formation and long carbon chain link. The formation of soot graphitization exhibited different morphologically behaviors: from flakes to onions to spheres with fewer branched chains. From the study of the laminar combustion characteristics of anisole, it can be found that the laminar burning velocities increased along with the increase of temperature, while the opposite trend was shown along with the increase of pressure. The sensitivity coefficient of naphthalene, the main soot precursor, revealed that the main promotional reactions for soot formation were R5 (O2 + H O + OH), R36 (CO + OH CO2 + H).

Abstract BackgroundHand, foot, and mouth disease (HFMD) is a highly contagious viral illness. Understanding the long-term trends of HFMD incidence and its epidemic characteristics under the circumstances of the enterovirus 71 (EV71) vaccination program and the outbreak of COVID-19 is crucial for effective disease surveillance and control. ObjectiveWe aim to give an overview of the trends of HFMD over the past decades and evaluate the impact of the EV71 vaccination program and the COVID-19 pandemic on the epidemic trends of HFMD. MethodsUsing official surveillance data from the Yunnan Province, China, we described long-term incidence trends and severity rates of HFMD as well as the variation of enterovirus proportions among cases. We conducted the autoregressive integrated moving average (ARIMA) of time series analyses to predict monthly incidences based on given subsets. The difference between the actual incidences and their counterfactual predictions was compared using absolute percentage errors (APEs) for periods after the EV71 vaccination program and the COVID-19 pandemic, respectively. ResultsThe annual incidence of HFMD fluctuated between 25.62 cases per 100,000 people in 2008 and 221.52 cases per 100,000 people in 2018. The incidence for men ranged from 30 to 250 cases per 100,000 people from 2008 to 2021, which was constantly higher than that for women. The annual incidence for children aged 1 to 2 years old ranged from 54.54 to 630.06 cases per 100,000 people, which was persistently higher than that for other age groups. For monthly incidences, semiannual peaks were observed for each year. All actual monthly incidences of 2014 to 2015 fell within the predicted 95% CI by the ARIMA(1,0,1)(1,1,0)[12] model. The average APE was 19% for a 2-year prediction. After the EV71 vaccination program, the actual monthly incidence of HFMD was consistently lower than the counterfactual predictions by ARIMA(1,0,1)(1,1,0)[12], with negative APEs ranging from −11% to −229% from January 2017 to April 2018. In the meantime, the proportion of EV71 among the enteroviruses causing HFMD decreased significantly, and the proportion was highly correlated (rP ConclusionsEV71 vaccination alleviated severe HFMD cases and altered epidemiological trends. The HFMD may also benefit from nonpharmaceutical interventions during outbreaks such as the COVID-19 pandemic. Further development of a multivalent virus vaccine is crucial for effectively controlling HFMD outbreaks. Policymakers should implement nonpharmaceutical interventions and emphasize personal hygiene for routine prevention when appropriate.

Aiming at the large-scale nonlinear deformation of the roadway in Liangjia Coal Mine, Shandong Province, the mudstone of the 1602 working face is taken as the research object. A high-precision mudstone weathering test system integrating monitoring and control was developed, and the weathering tests of expanded mudstone were carried out at 10 °C, 20 °C, 30 °C and 40 °C. The results show that the hygroscopic curves of expanded mudstone demonstrate a nonlinear growth trend at different temperatures, and the influence of temperature on the hygroscopic curves is less than 20%. From the overall law, it can be roughly divided into three stages: the strong hygroscopic stage, the hygroscopic deceleration stage and the stable hygroscopic stage. The maximum expansion rates of the samples were 4.1%, 5.3%, 6.2% and 6.8%, respectively, and the water content and expansion rates corresponding to different ambient temperature and humidity were generally “concave”. The mechanical tests show that the mechanical properties of mudstone decrease as the ambient temperature increases, and the corresponding compressive strength decreases by 16~50%. The linear degradation is obvious, and the gradual expansion of peak strain indicates that the plasticity of the rock increases and the elastic modulus decreases linearly.

Abstract The laminar combustion characteristics of CH4/air premixed flames with CO2 addition are systemically studied. Experimental measurements and numerical simulations of the laminar burning velocity (LBV) are performed in CH4/CO2/Air flames with various CO2 doping ratio under equivalence ratios of 1.0–1.4. GRI 3.0 mech and Aramco mech are employed for predicting LBV, adiabatic flame temperature (AFT), important intermediate radicals (CH3, H, OH, O) and NO x emissions (NO, NO2, N2O), as well as the sensitivity analysis is also conducted. The detail analysis of experiment and simulation reveals that as the CO2 addition increases from 0% to 40%, the LBVs and AFTs decrease monotonously. Under the same CO2 doping ratio, the LBVs and AFTs increase first and then decrease with the increase of equivalence ratio, and the maximum of LBV is reached at equivalence ratio of 1.05. The mole fraction tendency of important intermediates and NO x with equivalence ratio and CO2 doping ratio are similar to the LBVs and AFTs. Reaction H + O2 ⇔ O + OH is found to be responsible for the promotion of the generation of important intermediates and NO x under the equivalence ratios and CO2 addition through sensitivity analysis. The sensitivity coefficients of elementary reactions that the increasing of CO2 doping ratio promotes or inhibits formation of intermediate radicals and NO x decreases. Graphical abstract

This paper presents a new fabrication method utilizing lost foam casting as a processing technique to synthesize high-strength and ultra-wear-resistant particle reinforced iron matrix composites. The composite material incorporates large-sized WC-11Co reinforcement. The composite exhibits a multiphase microstructure composed of WC-11Co, α-Fe, and carbide precipitates that extend at different length scales. The precipitation of large-sized M3W3C (M = Fe, Co) type carbides at the WC-11Co/matrix interface is well controlled. A favorable reaction layer is formed between WC-11Co and the matrix. Nano-precipitates are pinned within the reaction layer, exhibiting a high degree of coherence with the iron matrix. The stress field at the interface is complex due to thermal stress, phase transformation stress, and microstress. The stress state between WC-11Co and the matrix consists of compressive residual stress-tensile residual stress-compressive residual stress, with compressive residual stress far exceeding tensile residual stress. The WC-11Co/Fe0.35C5CrMn composite exhibits outstanding compressive strength of 2.18 GPa and a fracture strain of approximately 24.6 %. Moreover, the composite demonstrates excellent wear resistance, with a threefold improvement compared to the matrix under severe wear conditions. The following mechanisms contribute to the enhanced mechanical properties: multiphase material system, coherent multiscale interfaces, grain refinement, dislocation strengthening, and residual stress strengthening.

With the rapid development of the information age, smart meters play an important role in the smart grid. However, there are more and more attacks on smart meters, which mainly focus on the identity authentication of smart meters and the security protection of electricity consumption data. In this paper, an efficient lightweight smart meter authentication scheme is proposed based on the Chinese Remainder Theorem (CRT), which can realize the revocation of a single smart meter user by publishing a secret random value bound to the smart meter identity. The proposed scheme not only protects the security of smart meter electricity consumption data by using encryption, but also resists identity attacks from both internal and external adversaries by using hash functions and timestamps. Experiment shows that the proposed scheme has lower computation overhead and communication overhead than other authentication schemes and is more suitable for smart meter authentication.

The objective of this study was to prepare biochar/clay composite particle (BCCP) as carrier to immobilize Ochrobactrum sp. to degrade ammonia nitrogen (NH4+-N), and the effects of calcined program and immobilizing material were investigated. Results reflected that the parameters were as follows: calcined temperature 400°C, heating rate 20°C min–1, and holding time 2 h, and the adsorption capacity could reach 0.492 mg g–1. Sodium alginate/polyvinyl alcohol, as embedding material, jointed with NH4+-N adsorption process and then degraded by Ochrobactrum sp. with 79.39% degradation efficiency at 168 h. Immobilizing Ochrobactrum sp. could protect strain from high salt concentration to achieve the exceeding degradation efficiency than free bacteria, but could not block the impact of low temperature.

Depth ambiguity is one of the main challenges of three-dimensional (3D) human pose estimation (HPE). The recent strategies of disambiguating have brought significant progress and remarkable breakthroughs in the field of 3D human pose estimation (3D HPE). This survey extensively reviews the causes and solutions of the depth ambiguity. The solutions are systematically classified into four categories: camera parameter constraints, temporal consistency constraints, kinematic constraints, and image cues constraints. This paper summarizes the performance comparison, challenges, main frameworks, and evaluation metrics, and discusses some promising future research directions.

The argillaceous weakly consolidated rock is a kind of soft rock that will bring great difficulties in the construction process. Specimens of such rock under different moisture contents are taken as the research object. By the Hopkinson pressure bar test (SHPB), the structural and mechanical characteristics of the rock under dynamic impact are analysed. With increasing moisture content, the transmitted wave amplitude decreases gradually, which indicates that the higher the moisture content of the rock is, the easier it is to deform under dynamic impact and the greater its plasticity. The boundary between plastic failure and brittle failure is 10% moisture content. Through a mercury injection test, the porosity variation is analysed. The porosity of the rock decreases with increasing moisture content after the same dynamic impact. The porosity curve can be roughly divided into two sections with a moisture content of 15% as the boundary. Based on a uniaxial compression test, the elastic modulus, peak strength, and residual strength of specimens after dynamic impact are analysed, and the mechanical properties of the rock are revealed. Its mechanical properties can be divided into three sections with a moisture content of 9.18% and 15.19%, and each section has obvious differences.

To evaluate the antimicrobial resistance and virulence gene characteristics of highly pathogenic Proteus mirabilis. In this study, we isolated P. mirabilis CC15031 from diarrhea dogs in China, tested the median lethal dose (LD50), and measured the minimum inhibitory concentration (MIC) of 10 different antibiotics commonly used in veterinary clinic. Meanwhile, we presented the complete genome sequence annotations to analyze the virulence and resistance formation mechanism. The results showed that the CC15031 presented relatively potent pathogenicity in mice (LD50 = 0.57 × 106 CFU) and exhibited a high degree of resistance to all the tested antimicrobial agents. The CC15031 genome of 4,031,742 bp with 3,745 predicted genes had an average gene length of 917 bp and 38.99% guanine-cytosine content. A new variant of an integrative and conjugative element with a type IV secretion system (217,446 bp) conferring multidrug resistance was identified and characterized by structural analysis in CC15031. These data provide a foundation for understanding the genomic features and antimicrobial resistance mechanisms of this pathogen.

Aiming at the problems of the low evaluation efficiency of the existing traditional cardiopulmonary resuscitation (CPR) training mode and the considerable development of machine vision technology, a quality evaluation algorithm for chest compressions (CCs) based on the OpenPose human pose estimation (HPE) model is proposed. Firstly, five evaluation criteria are proposed based on major international CPR guidelines along with our experimental study on elbow straightness. Then, the OpenPose network is applied to obtain the coordinates of the key points of the human skeleton. The algorithm subsequently calculates the geometric angles and displacement of the selected joint key points using the detected coordinates. Finally, it determines whether the compression posture is standard, and it calculates the depth, frequency, position and chest rebound, which are the critical evaluation metrics of CCs. Experimental results show that the average accuracy of network behavior detection reaches 94.85%, and detection speed reaches 25 fps.

Petroleum hydrocarbons can serve as a carbon source for marine phytoplankton; so, marine high-acid crude oil pollution events are likely to result in algal outbreaks or harmful algal blooms (HABs) in surface waters. Naphthenic acids (NAs) are the primary acidic component of crude oil, and red tide is of great concern due to its high diffusivity and strong destructive properties. It is important to study the mechanism of the toxic effect of NAs on the typical red tide algae, Heterosigma akashiwo, for the balance and stability of marine algae. The mechanism of NAs’ damage effect was investigated in terms of the antioxidant enzyme activity, cell number, the chlorophyll positive fluorescence parameters, and the cell morphology of microalgae. Experiments confirmed the hormesis of low-concentration (0.5, 2, and 4 mg/L) NAs on Heterosigma akashiwo, and the indicators of high-concentration (8 and 16 mg/L) NA exposures showed inhibition. In this study, the toxic effect of NAs on the target organism showed a clear concentration–dose relationship. The 16 mg/L NAs stress caused severe damage to the morphology and structure of the target biological cells in a short time (96 h), and the population growth decreased. The target organisms showed a staged oxidative stress response to NAs. The behavior in the low-concentration treatment groups showed toxicant excitatory effects on the photosynthetic efficiency and antioxidant enzyme activity of the target organisms. This study provides theoretical and practical data for the development of an important toxicological model of the toxicant’s excitement effects and antioxidant defense mechanisms. In addition, it provides prospective research data for the prediction and avoidance of ecological risk from NA pollution in marine environments.

Laminar diffusion flame was used to study the effect of ethanol on n-heptane flame in terms of the morphology and microstructure of soot under atomization combustion. For the same carbon mass flux at the outlet of the burner, the ratio of ethanol doping in n-heptane was changed, and the soot was collected from the axial positions of the flame at different heights using the thermophoresis probe method. The results showed that the flame height increased significantly with the increasing ratio of ethanol doping. When the ratio of ethanol and n-heptane (CE/CN) was 1.5, the flame height increased by 10 mm compared with that of pure n-heptane flame. Besides, the temperature in the center of the flame decreased with the increasing ratio of ethanol doping, but the temperature in the low position was higher than that in the pure n-heptane flame, and the temperature in the high position was lower than that in the pure n-heptane flame. However, the flame temperature was the highest when the proportion of ethanol in the mixture was greater than that of n-heptane. The temperature at the flame center decreased with the increasing ratio of ethanol doping, while the temperature at the flame edge increased with the ratio. The primary particle size of soot (soot size hereafter) in all working conditions increased with the increase of flame height, which was in line with the general growth law of soot. Moreover, the soot size at the same height decreased with the increasing ratio of ethanol doping, and this trend was most obvious at the flame height of 20 mm and 30 mm. Compared with pure n-heptane, when CE/CN was 1.5, the soot size at 20 mm and 30 mm decreased by an average of 34.83%, indicating that ethanol could inhibit the surface growth of soot particle. Furthermore, the density of soot particles collected by a single copper net decreased significantly, indicating that ethanol could reduce the production amount of soot.

Multiple preclinical evidences have supported the potential value of mesenchymal stem cells (MSCs) for treatment of acute lung injury (ALI). However, few studies focus on the dynamic tropism of MSCs in animals with acute lung injury. In this study, we track systemically transplanted human bone marrow-derived mesenchymal stem cells (hBMSCs) in NOD/SCID mice with smoke inhalation injury (SII) through bioluminescence imaging (BLI). The results showed that hBMSCs systemically delivered into healthy NOD/SCID mouse initially reside in the lungs and then partially translocate to the abdomen after 24 h. Compared with the uninjured control group treated with hBMSCs, higher numbers of hBMSCs were found in the lungs of the SII NOD/SCID mice. In both the uninjured and SII mice, the BLI signals in the lungs steadily decreased over time and disappeared by 5 days after treatment. hBMSCs significantly attenuated lung injury, elevated the levels of KGF, decreased the levels of TNF-α in BALF, and inhibited inflammatory cell infiltration in the mice with SII. In conclusion, our findings demonstrated that more systemically infused hBMSCs localized to the lungs in mice with SII. hBMSC xenografts repaired smoke inhalation-induced lung injury in mice. This repair was maybe due to the effect of anti-inflammatory and secreting KGF of hMSCs but not associated with the differentiation of the hBMSCs into alveolar epithelial cells.