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This study delves into the utilization of modern technology in rural policing, offering insights from front‐line police officers operating in the Chinese context. As rural areas globally grapple with unique policing challenges, the significance of this research extends beyond the borders of China. Findings indicate that technology, particularly video surveillance and communication platforms such as WeChat, has enhanced the responsiveness and overall capabilities of rural policing. The study sheds light on the dual nature of this technological adoption, highlighting its positive impact on policing practices while unraveling challenges, such as burnout and sustainability concerns. Notably, the study reveals that despite financial constraints hindering equipment maintenance and technological development in rural police departments, collaborations with commercial entities provide a viable avenue to alleviate such constraints. The global resonance of these findings underscores the broader implications for rural policing practices worldwide, emphasizing the need for strategic technological interventions to address challenges and optimize policing effectiveness in rural areas. [ABSTRACT FROM AUTHOR]

The information of fractures in rock mass is an essential indicator to evaluate the quality of rock mass. It is precise and efficient to obtain information of fractures by computer vision (CV)-based fracture detection technologies. However, rock masses in practical engineering always exhibit complex fractures with messy edges, shadows, and uneven rock surfaces. These factors negatively impact the effectiveness of fracture detection algorithms. To address such issues, this paper proposes a confidence score-based rock fracture detection algorithm that can effectively identify fractures in complex situations. The image with fractures is traversed to acquire candidate points at first. We proposed a method to evaluate the confidence scores of these candidate points according to the values of Hessian matrix eigenvalues, the degree of symmetry, and the gray-scale value. The candidate points are further filtered through threshold restriction and non-maximum suppression. Furthermore, the complete centerlines of the fractures are obtained by the connection of the candidate points and the connection of discontinuous centerlines. Finally, pseudo-fractures and noise are eliminated to get complete fractures. Experimental results show that the newly proposed algorithm can accurately identify fractures in complex situations. The algorithm avoids interference and noise, which achieves more precise results than other conventional fracture detection algorithms, is an effective method to identify fractures in rocky geological engineering and can also serve as a guide for other relevant fracture identification algorithm in rock mass. [ABSTRACT FROM AUTHOR]

β‐fluorocarbanions have garnered considerable attention for their dual reactivity in nucleophilic processes and β‐fluorine elimination. In this study, a thorough computational analysis was conducted to explore the reactions of α‐(trifluoromethyl)styrenes with 2‐pyridones to delineate the factors determining protonation or defluorination pathways for the in situ generated β‐fluorocarbanions under varied basic conditions. Our findings illuminate the critical role of organobase basicity in steering the direction of the competitive protonation and β‐fluorine elimination reactions. We propose the use of pKaH values of organobases as a quantitative indicator for discerning the predominant reaction pathways. This provides an efficient approach to predict and control the reaction outcome, facilitating the deliberate design of reactions to leverage the unique reactivity of β‐fluorocarbanions in the realm of fluorine chemistry. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau, as a major elevated heat source, plays a critical role in the Asian monsoon and global climate. Observational data revealed significant correlations between spring surface air temperature in the Tibetan Plateau and downstream summer precipitation interannual variations. Sensitivity experiments using the regional Climate-Weather Research and Forecasting model (CWRF) were conducted to understand the physical processes and mechanisms underlying such delayed teleconnections. A positive temperature forcing was imposed over the plateau on the surface and subsurface soil layers only at the initial conditions around May 1st, 2003. This regional forcing quickly induces positive perturbations in local air temperature and, more importantly, maintains its signal in local soil, especially deep layers, for several months. Consequently, the soil temperature serves as a charged capacitor to modulate the planetary atmospheric circulation and through Rossby wave chains to cause significant summer precipitation anomalies over broad regions. This relayed teleconnection pattern is consistent with that identified from observational data records and CWRF climate simulations during 1980–2015. Diagnostic analyses of observations and simulations suggest that the Tibetan Plateau heating significantly impacts summer East Asian monsoon climate through influencing the South Asian High and shifting the East Asian jet. [ABSTRACT FROM AUTHOR]

Goose astrovirus type 2 (GAstV-2) is a novel pathogen causing visceral gout in goslings; it not only causes necrosis of renal epithelial cells but also causes spleen damage, indicating that GAstV-2 induces immunosuppression in goslings. However, to date, the interaction between GAstV-2 and immune cells remains unclear. In this study, peripheral blood lymphocytes and macrophages were isolated from goslings without GAstV-2 infection and then inoculated in vitro with GAstV-2, and the virus localization in the lymphocytes and macrophages, proliferation and apoptosis of lymphocytes, and phagocytic activity, reactive oxygen species (ROS) and nitric oxide (NO) production, and cell polarity in macrophages were determined. The results showed that GAstV-2 was observed in the cytoplasm of CD4 and CD8 T cells and macrophages, indicating that GAstV-2 can infect both lymphocytes and macrophages. GAstV-2 infection reduced the lymphocyte proliferation induced by Concanavalin A and lipopolysaccharide stimulation and increased the lymphocyte apoptosis rate and mRNA expression of Fas, demonstrating that GAstV-2 causes damage to lymphocytes. Moreover, GAstV-2 infection enhanced phagocytic activity and production of ROS and NO and induced a proinflammatory phenotype in macrophages (M1 macrophages), indicating that macrophages play an antiviral role during GAstV-2 infection. In conclusion, these results demonstrate that GAstV-2 infection causes damages to lymphocytes, and host macrophages inhibit GAstV-2 invasion during infection. [ABSTRACT FROM AUTHOR]

SnO 2 has been recognized as one of the most potential anodes of lithium-ion batteries due to its high theoretical specific capacity, low cost, simple synthetic method, and environmental friendliness. However, the application of SnO 2 is hindered owing to its huge volume expansion (∼300 %) and poor electronic conductivity. In this work, carbon-coated SnO x containing some SnO anchored on the phosphorus-doped carbon framework (SnO x /C–P@C) has been fabricated via a novel, simple and green precipitation route using phytic acid as the complexing agent, carbon and phosphorus sources, and glucose as the second carbon source. Phosphorus-doped carbon framework in situ forms via calcining phytic acid at a high temperature. Phosphorus doping can further enhance the electronic conductivity of carbon. The carbon framework can provide sufficient buffer space to make the SnO x particles have good dispersion. The carbon layer from glucose can prevent the direct contact between SnO x and the electrolyte to decrease the side reactions and then reinforce the structure of SnO x /C–P@C. The synergistic effect of the double carbon effectively controls the volume expansion, enhances the electronic conductivity and diffusion coefficient of Li+ ions as well as capacitive contribution ratio, and reduces the charge transfer resistance of SnO x /C–P@C. The SnO x /C–P@C-0.5 sample with the carbon content of 25.8 wt% exhibits outstanding electrochemical performance. At 0.1 A g−1, the discharge specific capacity of 776.2 mAh g−1 can be reached after 100 cycles. At 0.5 A g−1, 555.5 mAh g−1 is still delivered after 200 cycles. Moreover, the sample shows good potential practical applications in the LiNi 0.5 Mn 1.5 O 4 //SnO x /C–P@C-0.5 full cell. 687.9, 597.1, 510.1, 434.8 and 595.6 mAh g−1 are retained for the full cell at 0.1, 0.2, 0.5, 1 and 0.1 C, respectively. The full cell cycling for 200 cycles at 0.5 C can still light up the light-emitting diode (LED) bulbs. [Display omitted] • Phytic acid is firstly used as P and C sources to synthesize SnO 2 /C–P@C. • The synthetic route is simple, low cost and environmental friendliness. • The double carbon greatly improves the electrochemical performance of SnO 2 /C–P@C. • SnO 2 /C–P@C holds significantly practical value in full cells. [ABSTRACT FROM AUTHOR]

Mounting evidence has indicated the essential role of tissue-resident memory T (TRM) cells for frontline protection against viral infection and for cancer immune surveillance (Mueller SN, Mackay LK. Tissue-resident memory T cells: local specialists in immune defense. Nat Rev Immunol 2016, 16, 79–89. doi:10.1038/nri.2015.3.). TRM cells are transcriptionally, phenotypically, and functionally distinct from circulating memory T (Tcirm) cells. It is necessary to understand the unique ontogenetic mechanism, migratory regulation, and biological function of TRM cells. In this review, we discuss recent insights into cellular mechanisms and discrete responsiveness in different tissue microenvironments underlying TRM cell development. We also emphasize the translational potential of TRM cells by focusing on their establishment in association with improved protection in mucosal tissues against various types of diseases and effective strategies for eliciting TRM cells in both pre-clinical and clinical studies. Recent insights into cellular mechanisms and discrete responsiveness in different tissue microenvironments underlying TRM development. Graphical Abstract [ABSTRACT FROM AUTHOR]

Melatonin has been proved to be involved in testosterone synthesis, but whether melatonin participates in testosterone synthesis by regulating miRNA in Leydig cells is still unclear. The purpose of this study is to clarify the mechanism of melatonin on Leydig cells testosterone synthesis from the perspective of miRNA. Our results showed that melatonin could significantly inhibit testosterone synthesis in rooster Leydig cells. miR-7481-3p and CXCL14 were selected as the target of melatonin based on RNA-seq and miRNA sequencing. The results of dual-luciferase reporter assays showed that miR-7481-3p targeted the 3′-UTR of CXCL14. The overexpression of miR-7481-3p significantly inhibited the expression of CXCL14 and restored the inhibitory role of melatonin testosterone synthesis and the expression of StAR, CYP11A1, and 3β-HSD in rooster Leydig cells. Similarly, interference with CXCL14 could reverse the inhibitory effect of melatonin on the level of testosterone synthesis and the expression of StAR, CYP11A1, and 3β-HSD in rooster Leydig cells. The RNA-seq results showed that melatonin could activate the PI3K/AKT signal pathway. Interference with CXCL14 significantly inhibited the phosphorylation level of PI3K and AKT, and the inhibited PI3K/AKT signal pathway could reverse the inhibitory effect of CXCL14 on testosterone synthesis and the expression of StAR, CYP11A1 and 3β-HSD in rooster Leydig cells. Our results indicated that melatonin inhibits testosterone synthesis by targeting miR-7481-3p/CXCL14 and inhibiting the PI3K/AKT pathway. [ABSTRACT FROM AUTHOR]

The Dahuoluo pill (DHLP) is a classic Chinese patent medicine used to treat rheumatoid arthritis and other conditions. However, there has been no research on the chemical components of DHLP and the mechanisms by which it ameliorates rheumatoid arthritis. Hence, we analysed the chemical components of DHLP and the DHLP components absorbed in blood by using ultraperformance liquid chromatography-Q-exactive-orbitrap-mass spectrometry. We then used network pharmacology to predict the underlying mechanisms by which DHLP ameliorates rheumatoid arthritis. We identified 153 chemical compounds from DHLP, together with 27 prototype components absorbed in blood. We selected 48 of these compounds as potential active ingredients to explore the mechanism. These compounds are related to 88 significant pathways, which are linked to 18 core targets. This study preliminarily reveals the potential mechanisms by which DHLP ameliorates rheumatoid arthritis and provides a basis for further evaluation of the drug's efficacy. [ABSTRACT FROM AUTHOR]

Tea varieties exhibit seasonal theanine accumulation, with the high-theanine tea variety Rougui having a diverse root microbiota rich in nitrogen-related microbes. A synthetic community derived from Rougui roots enhances tea growth and theanine synthesis under nitrogen deficiency, emphasizing the microbiota's pivotal role. [ABSTRACT FROM AUTHOR]

Choosing an accurate model order is one of the important sections in system identification. Traditionally, the model order selection of a nonlinear system depends on a predetermined model. However, it requires excess calculation and is impossible to get rid of the trouble of the structural design of the model, once the specific model was determined. A false nearest neighbor (FNN) algorithm that only relies on input-output data to estimate the model order is proposed here. Due to the FNN algorithm is sensitive to its own threshold which is a crucial constant for evaluating the model structure, Gaussian mixture model (GMM) clustering based on a genetic version of the expectation-maximization (EM) algorithm and minimum description length (MDL) criterion is developed in this paper, where the order can be determined without relying on a specific model. The GMM clustering is proposed to calculate the threshold of the FNN. Then, the genetic algorithm and MDL criteria are embedded to optimize the calculation of the EM algorithm as reduce the influence of initial values and not prone to fall into local extreme values as well. Three examples are given here to indicate the superiority of this technique: simulation of a strongly nonlinear system, isothermal polymerization process, and Van der Vusse reaction in relevant reference. Finally, some typical modeling methods are conducted to confirm the validity of this approach. [ABSTRACT FROM AUTHOR]

Four new multifunctional polymers (P1, P2, P3, and P4) containing EDOT units were synthesized by the Stille coupling reaction. A PL spectrum test found that the introduction of large conjugated groups led to strong fluorescence emission in all polymers. Among the electrochromic and switch properties, these polymer films exhibited reversible color changes, as well as good coloring efficiency. Electrochemical experiments found that the initial oxidation potentials of the polymers were 1.27 V, 1.67 V, 1.78 V, and 1.58 V, respectively. Among them, P3 showed a higher coloring efficiency (283.3 cm2·C−1), and P2 showed a shorter response time (tc = 2.2 s, tb = 2.8 s). These polymers all exhibited electrochromic and resistive switching storage characteristics. They have good solubility in many organic solvents. In the resistance switch memory characteristics, all polymers had obvious memristive properties, and P4 exhibited a larger switch current ratio (2527.42) and a smaller threshold voltage (0.9 V). [ABSTRACT FROM AUTHOR]

This paper combines the mechanical efficiency theory and finite time thermodynamic theory to perform optimization on an irreversible Stirling heat-engine cycle, in which heat transfer between working fluid and heat reservoir obeys linear phenomenological heat-transfer law. There are mechanical losses, as well as heat leakage, thermal resistance, and regeneration loss. We treated temperature ratio x of working fluid and volume compression ratio λ as optimization variables, and used the NSGA-II algorithm to carry out multi-objective optimization on four optimization objectives, namely, dimensionless shaft power output P ¯ s , braking thermal efficiency η s , dimensionless efficient power E ¯ p and dimensionless power density P ¯ d . The optimal solutions of four-, three-, two-, and single-objective optimizations are reached by selecting the minimum deviation indexes D with the three decision-making strategies, namely, TOPSIS, LINMAP, and Shannon Entropy. The optimization results show that the D reached by TOPSIS and LINMAP strategies are both 0.1683 and better than the Shannon Entropy strategy for four-objective optimization, while the D s reached for single-objective optimizations at maximum P ¯ s , η s , E ¯ p , and P ¯ d conditions are 0.1978, 0.8624, 0.3319, and 0.3032, which are all bigger than 0.1683. This indicates that multi-objective optimization results are better when choosing appropriate decision-making strategies. [ABSTRACT FROM AUTHOR]

This article aims to analyze the emotional injury and behavioral consequences that police officers in China experience after they have been violently attacked (e.g., when police are victims of violent crimes). The analysis was based on self-narration from police officers who were victimized (from here "police victims"). First, the study explored the emotional trauma caused by violent and nonviolent attacks on police victims. Second, this study explored the impact of this violence on the police community. Finally, the study assessed the impact of violent attacks on police enforcement capabilities. Research shows that police in China have become victims of violent attacks that may have caused emotional damage. However, the extent and consequences of this emotional damage are not clear and deserve further discussion. Therefore, this research attempts to contribute to an in-depth discussion of this topic. The research used a focus group format to interview police victims (n = 40). The interviews included questions about emotional damage, occupational hazards, ensuing self-doubt, long-term behaviors, returning to work, and self-protection. The results show that police victims have suffered severe emotional damage, which may affect their ability to continue in law enforcement. It is particularly noteworthy that some police officers received unequal treatment, which led to the breakdown of family and social relationships. Chinese police victims face severe emotional damage. They have suffered great mental pressure and bad social evaluation. A reasonable recovery plan is required to help police victims return to normal life. The recovery plan should aim to improve the lives of police victims, especially by helping them relieve stress. [ABSTRACT FROM AUTHOR]

• An ultrasonic enhanced atmospheric evaporation crystallization process was proposed. • The yield of (NH 4) 2 SO 4 product can be increased by 52.9% by this new method. • The mechanism of ultrasonic enhancement was discussed. • The supersolubility of the (NH 4) 2 SO 4 solution was reduced from 937.5 to 833.33 g/L. Ultrasound enhanced evaporating crystallization has been proposed to solve the problems of low crystallization yield and uneven particle size in the evaporating crystallization process of ammonium sulfate solution at atmospheric pressure. The effects of key operating parameters, including the ultrasound power, stirring speed, pH value, and ultrasound time, on the yield of ammonium sulfate product and the duration of solid–liquid transformation time are studied. The results show that the ultrasound crystallization can increase the ammonium sulfate yield by 52.9 %, reduce the solid–liquid transformation time of ammonium sulfate by 10 %, and obtain ammonium sulfate products with higher crystallinity and more uniform particle size. Ultrasound promotes the crystallization of ammonium sulfate by enhancing the transfer of heat in the solution and reducing the supersolubility of the ammonium sulfate solution from 937.5 g/L to 833.33 g/L. This study provides experimental justification for the use of ultrasound in atmospheric evaporative crystallization. [ABSTRACT FROM AUTHOR]

SUMMARY: Reactive oxygen species (ROS) overproduction leads to oxidative damage under almost all stress conditions. Lesion‐Simulating Disease (LSD), a zinc finger protein, is an important negative regulator of ROS accumulation and cell death in plants. However, the in vivo role of LSD in cassava (Manihot esculenta) and the underlying molecular mechanisms remain elusive. Here, we found that MeLSD3 is essential for the oxidative stress response in cassava. MeLSD3 physically interacted with ascorbate peroxidase 2 (MeAPX2), thereby promoting its enzymatic activity. In addition, MeLSD3 also interacted with the nuclear factor YC15 (MeNF‐YC15), which also interacted with nuclear factor YA2/4 (MeNF‐YA2/4) and nuclear factor YB18 (MeNF‐YB18) to form an MeNF‐YC15–MeNF‐YA2/4–MeNF‐YB18 complex. Notably, MeLSD3 positively modulated the transcriptional activation of the MeNF‐YC15–MeNF‐YA2/4–MeNF‐YB18 complex by interacting with the CCAAT boxes of the promoters of glutathione S‐transferases U37/U39 (MeGST‐U37/U39), activating their transcription. When one or both of MeLSD3 and the MeNF‐YC15–MeNF‐YA2/4–MeNF‐YB18 complex were co‐silenced, cassava showed decreased oxidative stress resistance, while overexpression of MeGST‐U37/U39 alleviated the oxidative stress‐sensitive phenotype of these silenced plants. This study illustrates the dual roles of MeLSD3 in promoting MeAPX2 activity and MeNF‐YC15–MeGST‐U37/U39 regulation, which underlie the oxidative stress response in cassava. Significance Statement: In response to oxidative stress, MeLSD3 physically interacts with MeAPX2 to promote its activity, and MeLSD3 also interacts with MeNF‐YC15 to promote the transcriptional activation of MeGST‐U37/U39 by forming a heterotrimeric complex with MeNF‐YA2/4 and MeNF‐YB18 in cassava (Manihot esculenta). [ABSTRACT FROM AUTHOR]

In this article, the magnetoelastic nonlinear free vibration of a thin conductive annular plate under the nonuniform toroidal magnetic field is investigated, where the magnetic field is generated by a long straight current‐carrying wire. Based on electromagnetic theory, expressions of the nonuniform magnetic field, electromagnetic forces are deduced. The nonlinear free vibration equation of plate is derived by using the Hamilton principle. Considering different boundary conditions, the axisymmetric vibration differential equation is achieved by the Galerkin method. The method of multiple scales is employed to obtain the second‐order approximate analytical solutions and natural frequency. In numerical calculation, the characteristics of nonlinear natural vibration and singular points varying with different parameters, for example, current intensity and plate size, are presented, respectively. The results indicate that, with the increase of current, natural frequency increases and then stabilizes in the inner‐clamped and out‐free (C‐F) boundary, but decreases and stabilizes in the cases of the inner‐clamped and out‐clamped (C‐C) boundary or inner‐simply and out‐simply (S‐S) boundary. Moreover, when wire current is off, natural frequency maintains a constant, where the equilibrium solution of the system is a center. In addition, for all boundary conditions, natural frequency increases significantly with increase of internal radius and thickness, but decreases with the increase of outer radius. [ABSTRACT FROM AUTHOR]

Heatwaves can produce catastrophic effects on public health and natural systems, especially under global warming. There are two methods to measure heatwaves, computed by relative and absolute thresholds, namely relative and absolute heatwaves (RHWs and AHWs). Generally, AHWs mostly occur in hot areas because of fixed thresholds, while RHWs represent anomalous events for the local climate, making them possible everywhere in the warm season. Based on observations and CMIP6 outputs, this study compared AHWs and RHWs in Eastern China (EC) with five sub-regions [Northeast China (NEC), North China (NC), Lower Yangtze River (LYR), Middle Yangtze River (MYR) and South China (SC)]. Similarities among RHWs and AHWs were found in present-day trends (1995–2014) and spatial distributions. The heatwave intensity/days for RHWs and AHWs both displayed highest future increases in northern/southern EC, and the increases for 2081–2100 would be 1.5 times as high as 2041–2060. All these similarities illustrate that applying either relative or absolute thresholds in EC, historical temporal variations, changing future spatial patterns, and increasing ratio from 2081–2100 to 2041–2060, would show reliable results. As far as differences are concerned, RHWs were observed across the entire EC, while AHWs did not show up in parts of NC and NEC. Considering model performance, RHWs would perform better than AHWs in most areas of EC. The annual heatwave intensity/days were higher for RHWs than for AHWs during present-day and future periods, which might overestimate heat-related risks. Overall, this study recommended RHWs for heatwave analyses, particularly for future projections, but for risk assessment, the choice of thresholds is crucial. The results reinforced the necessity to further improve model performance to address various needs. [ABSTRACT FROM AUTHOR]

Various impeded flow particle receivers were proposed to prolong the particle residence time but always faced the risk of thermal deterioration and the difficulty of real-time particle velocity control. Herein, we reported a novel impeded flow particle receiver to solve above problems and further have the potential to control the particle velocity distribution, which could provide a heat source with better stability, better uniformity and higher temperature for subsequent thermal power generation and other thermal applications. In this receiver, the friction along the path and the gate valves at outlet act as the obstruction structures to allow the particles to move slowly and controllably in the form of a sliding-bed, which is why we call this receiver a sliding-bed receiver. The sliding-bed receiver's structural validity and operational characteristics at different working conditions were detailly investigated with both experimental and numerical methods. Experimental results showed that the outlet particle temperature and efficiency could reach 847 °C and 77.2% under a solar simulator of 4 kW. An optical and thermal coupling model was developed and revealed an improved particle temperature of 1350 °C and efficiency of 82% under higher incident power. The effects of the effects of the incident power distribution, the particle velocity distribution and the quartz glass on aperture on the receiver performance were detailly analyzed, which could also help optimize the design and operation of other particle receivers such as free-falling particle receivers. [Display omitted] • A sliding-bed particle receiver was elaborately designed and tested. • Better stability and controllability of endothermic process was achieved. • Outlet temperature of 847 °C was reached under a solar simulator of 4 kW. • Outlet temperature of 1350 °C would be achieved under higher incident power. • Some design and operation guidelines for particle receivers were given. [ABSTRACT FROM AUTHOR]

Polar geological drilling is crucial to investigating the earth's environment and climate evolution. Hydraulic fracturing occurs around the ice holes when drilling into the complex debris-rich ice before entering the bedrock. Based on the nonlocal theory, the ice-debris structure is considered in the stability of the borehole wall, and a peridynamics model is developed to explore fracture initiation and propagation characteristics around the debris-rich ice hole. The integrated equation describes the mechanical behavior of ice holes, and the continuous and discontinuous spaces are described uniformly around debris-rich ice holes, avoiding the singularity of local continuum mechanics at the interface and crack tip. In this paper, the separation behavior of the interface is simulated between ice and debris. The cracking propagation process, the influence of debris size and shape, and horizontal pressure are analyzed. The results show that at a hydraulic pressure of 4.0 MPa, 8 radial cracks are initiated from the wall of the ice hole containing circular and elliptical debris, with the final crack volume of 0.66% and 1.40%, respectively. The cracks near the hole wall propagate a circumferential direction after turning or branching, leading to peeling in the ice hole containing elliptical debris with inclination angles of 30° and 60°. Hydraulic pressure balances stress distribution around debris-rich holes when horizontal pressure ranges from 1.2 to 2.4 MPa. When drilling into debris-rich ice formations at different debris and horizontal pressures, it is imperative to adjust promptly the density of drilling fluid. This adjustment aims to regulate the hydraulic pressure within the hole, minimize crack distribution, and ensure safe access to bedrock for coring. • A crack model for debris-rich ice holes is proposed based on peridynamics. • Influence mechanism of debris size, shape, and pressure is studied on cracks. • The convergence of circular and radial cracks leads to hole wall peeling. [ABSTRACT FROM AUTHOR]

• Elastic border plate's nonlinear vibration is studied first in induced magnetic field. • Mode shape function in polynomial form satisfying elastic boundaries are resolved. • Complex numerical calculation from nonuniformity, nonlinearity and boundary is solved. • Structural, electromagnetic, time parameters effect on system stability is analyzed. The aim of this article is to investigate nonlinear free vibration and electromagnetic mechanical behavior of a conductive annular plate with elastic boundary in induced non-uniform magnetic field. On basis of magneto-elastic vibration control equation of conductive plates, displacement solution for plates under complex elastic constraints is first solved, and the axisymmetric nonlinear differential equation for plate is derived by combining Galerkin method. Introducing the multi-scale method to solve the differential equation of elastic boundary plate in induced magnetic field to achieve the analytical expression for natural frequency including current and elastic stiffness terms, and the variation of system singularity is analyzed through stability discriminant. Through numerical method, the nonlinear frequency variation curves, electromagnetic characteristic curves, stability area and phase trajectory graphics of singularities with various control parameters are presented. The result accuracy verification was also conducted in comparison to relevant literature and numerical solutions. The interesting and key findings revealed that, under internal diameter clamped and outer diameter elastically supported boundary, the variation of natural frequency with current, time, the nonlinear soft and hard characteristics are completely opposite to rest two boundaries. The elastic stiffness may significantly increase natural frequency, but does not change the soft or hard characteristics of system. With influence of elastic boundaries, the distribution of electromagnetic force and torque in radial direction of plate becomes quite complex under non-uniform magnetic field. In addition, wire current may change the type of system singularity as current increases. [ABSTRACT FROM AUTHOR]

Attention and working memory (WM) are distinct cognitive functions, yet given their close interactions, it is often assumed that they share the same neuronal mechanisms. We show that in macaques performing a WM-guided feature attention task, the activity of most neurons in areas middle temporal (MT), medial superior temporal (MST), lateral intraparietal (LIP), and posterior lateral prefrontal cortex (LPFC-p) displays attentional modulation or WM coding and not both. One area thought to play a role in both functions is LPFC-p. To test this, we optogenetically inactivated LPFC-p bilaterally during different task periods. Attention period inactivation reduced attentional modulation in LPFC-p, MST, and LIP neurons and impaired task performance. In contrast, WM period inactivation did not affect attentional modulation or performance and minimally affected WM coding. Our results suggest that feature attention and WM have dissociable neuronal substrates and that LPFC-p plays a critical role in feature attention, but not in WM. • Most cortical neurons show WM or attention signals, and not both • LPFC-p inactivation during attention, but not during WM, impairs task performance • Inactivation reduces neuronal attentional effects but minimally affects WM signals • Feature attention and WM thus have dissociable neuronal substrates Mendoza-Halliday and colleagues show that in multiple cortical areas, neurons modulated by visual feature attention are largely different from those encoding working memories. By optogenetically inactivating LPFC-p during attention or working memory, they further show that it plays a critical role in attentional modulation, but not in working memory. [ABSTRACT FROM AUTHOR]

Photon-enhanced thermionic emission (PETE) is a promising method for increasing current density at relatively low cathode temperatures, but is susceptible to the space charge effect. In this study, we propose a novel PETE device model in which the space-charge barrier is relaxed by photon-excited cesium ions. The decrease in maximum efficiency with interelectrode gap is more gradual compared to previous studies. We investigate the effects of cathode materials properties (band gap and electron affinity) and operating conditions (cathode temperature and interelectrode gap) on PETE performance, and identify optimal performance conditions. Our findings show that the optimal gap range exceeds 5 μm and near field radiation loss can be minimized, providing an important opportunity for designing PETE device with larger interelectrode gaps and higher solar flux concentrations. • An existing model of space charge effect is updated to include neutralization. • Space charge barrier is reduced by photon excitation of cesium ions. • The maximum efficiency and the optimal gap ranges are determined. • The influences of key parameters on the performance are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phytic acid is firstly used as P and C sources to synthesize SnP 2 O 7 /C-P@C-N. • N-P co-doped carbon improves the electrical conductivity and generates defects. • SnP 2 O 7 /C-P@C-N exhibits good rate capability and cycling performance. • SnP 2 O 7 /C-P@C-N holds significantly practical value in full cells. N-doped carbon-coated SnP 2 O 7 anodes anchored on P-doped carbon framework (SPO/C-P@C-N) have been successfully synthesized via a novel and environmentally friendly method, using a green raw material of phytic acid as phosphorus and carbon sources, and dimethylimidazole as the second carbon source and nitrogen source. N-doped carbon coating and P-doped carbon framework inhibit the volume shrinkage and expansion, improve the electronic conductivity and diffusion coefficient of Li+ ions as well as capacitive contribution ratio, reduce the charge transfer resistance and the particle size, and then enhance the electrochemical performance of SPO/C-P@C-N. SPO/C-P@C-N-1.2 with the carbon content of 18.5 wt% exhibits excellent electrochemical performance. The discharge specific capacity is 416.6 mAh/g at 0.5 A/g after 200 cycles. 234.3 mAh/g is kept at 2 A/g for the 1000th cycle. In addition, the discharge specific capacity of the LiNi 0.5 Mn 1.5 O 4 //SPO/C-P@C-N-1.2 full cell is 206.6 mAh/g for the 200th cycle at 0.5C in 1.4–4.4 V. The full cell can power green, red, blue, and orange light-emitting diode (LED) bulbs, as well as LED small light strings and heart-shaped circuit boards. It is the first report on SnP 2 O 7 successfully applied to full cells, demonstrating the potential application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cyclodextrin-based aerogels show excellent broadband sound absorption performance. • Cyclodextrin-based aerogels combine good mechanical properties. • Sound absorption ability of aerogels is stable due to hydrophobicity and elasticity. The rapid development of human society has brought much noise pollution, which damage our quality of life seriously. However, it is difficult to design a material with broadband sound absorption performance. Herein, we explored composite aerogels composed of cyclodextrin, CNC and siloxane. The resulting CCA aerogels have broadband sound absorption performance. The bandwidth with a sound absorption coefficient greater than 0.8 can be over 5000 Hz (750–1250, 1750–6400 Hz), and the best sound absorption coefficient appears at the low frequency (around 768 Hz, 0.95). The CCA aerogels also show good elasticity and their mechanical properties are better than most sound-absorbing materials. Furthermore, CCA aerogels exhibit stable broadband sound absorption performance in humid environment or after compression treatment. [ABSTRACT FROM AUTHOR]

• Nonlinear constitutive models of fractures are considered in coupled THMC modeling. • Multi-stage alternate hydraulic and chemical stimulations are successfully modeled. • A robust approach of optimizing chemical stimulation parameters is developed. Chemical stimulation, as a soft stimulation method, has been increasingly used in carbonatite geothermal reservoirs, but selecting and designing an optimal scheme of chemical stimulation is still challenging due to lack of robust and reasonable modeling tools. In this study the coupled thermal-hydro-mechanical-chemical (THMC) modeling framework is further developed to simulate chemical stimulation process in carbonatite geothermal reservoirs containing a system of intersecting fractures by considering the nonlinear constitutive models of rock fractures, which reflect the changes in fracture aperture mediated by chemical and mechanical processes. Based on a pilot field test of multi-stage alternate hydraulic and chemical stimulations in the geothermal well D22, Xiong'an New Area, China, the developed modeling framework is verified. The results showed that multi-stage alternate hydraulic and chemical stimulations can efficiently stimulate the carbonatite geothermal reservoirs of low permeability. In addition, a robust optimization approach is proposed to determine the proper human-controlled parameters in chemical stimulation including acid concentration, injection rate and total volume of acid solution. [ABSTRACT FROM AUTHOR]

• A hybrid model with validated numerical model, DNN and meta -heuristic algorithms is developed. • Solar receivers are applied in diverse application scenarios. • Multi-objective optimizations are studied to ensure the safe and optimal performance of receivers. • Maximum heliostat scale is found for solar receivers due to material limitations. • The proposed method effectively reduces the maximum receiver tube wall temperature. Efficient and secure operation of solar receivers is key to the development of concentrated solar power (CSP). Its precise and quick optimization is essential for receiver to achieve optimum thermal performance and safety across diverse application scenarios. In this study, we propose a hybrid model based on numerical simulation and deep learning to achieve this target. The hybrid model accounting for conduction, convection and radiation shows a small relative error (<2%) in over 96 % cases. We apply the model to two different application scenarios considering multiple performance objectives simultaneously and demonstrate that it can identify optimal structure parameters and heliostat scale for each inlet flow rate of the receiver. In combination with gas turbines, maximum efficiencies of 48.9 %, 53.2 %, and 56.8 % are achieved for flow rates of 0.5, 0.75, and 1 kg/s, respectively. When integrated into heating systems, the receiver achieves a maximum thermal efficiency of 89.8 % with a heliostat field scale of 5.76 MW. Furthermore, for the operation optimization, the proposed aiming strategy results in a 76 ℃ reduction in maximum tube wall temperature compared to the conventional aiming strategy. Our approach not only provides an advanced solution for rapid cavity receiver design and operation optimization but also has the potential for extension to other structures. [ABSTRACT FROM AUTHOR]

Aims: The purpose of the present study was to investigate the correlation between the number of live-birth pregnancies and metabolic syndrome (MetS) in Chinese women according to menstruation history. Methods: Registry data for all pregnancies in a cohort of 6157 Chinese women aged 40 years or older were obtained and the number of live-birth pregnancies were enumerated. We defined MetS using five criteria: impaired insulin metabolism and glucose tolerance, obesity in the abdominal area, dyslipidemia, and hypertension. Multivariate logistic regression analysis was conducted to assess potential risk factors for MetS. Postmenopausal women with three or more of live-birth pregnancies had the highest prevalence of MetS (P < 0.05). Results: Among the 6157 females aged 40 years or older in Luzhou city, 2143 (34.8%) participants had incident MetS. The number of live-birth pregnancies was significantly correlated with age and fasting blood glucose (FBG) level (P < 0.05). The prevalence of MetS increased with the number of live-birth pregnancies (P < 0.01), and the frequency in postmenopausal women was significantly higher than that in premenopausal women (P < 0.001). In the binary logistic regression model, menopausal status [OR = 0.343 (0.153–0.769), P < 0.001] were significantly associated with an increased risk of MetS. Conclusions: The number of live-birth pregnancies is correlated with an increased risk of MetS in Chinese women aged 40 years and over, especially in postmenopausal women. Greater attention should be paid to postmenopausal women who have had multiple live-birth pregnancies with a view to intervening early to prevent related diseases. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structure of Bi 2 MoO 6 was tuned by adjusting the alkali solution concentration. • Concentration of oxygen vacancy increased obviously due to the alkali etching. • Bi 2 MoO 6 treated by 0.075 M solution showed an excellent photo-activity. As a layered photocatalyst, the photogenerated carriers separation efficiency of bismuth molybdate (Bi 2 MoO 6) can be improved by introduction of oxygen vacancy. The alkali etching method provides a facile structural tuning way for modifying the bismuth-based semiconductors. Defect state bismuth molybdate (Bi 2 MoO 6) photocatalyst was synthesized by alkali etching. The structure of Bi 2 MoO 6 was tuned by adjusting the concentration of alkali solution. The phase structure, morphology, surface chemistry, and optical property of Bi 2 MoO 6 were characterized by kinds of characterization methods such as X-ray diffraction, scanning electron microscope, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance absorption spectroscopy. The phase of Bi 2 MoO 6 can be transformed to Bi 2 O 3 accompanied with the change of morphology due to the etching of molybdenum atom and oxygen atom from the Bi 2 MoO 6 body structure by sodium hydroxide solution. Meanwhile, the concentration of oxygen vacancy increased obviously as indicated by the XPS results. Therefore, the separation efficiency of photogenerated carriers was enhanced because of the promotion of oxygen vacancy. Alkali etching Bi 2 MoO 6 by 0.075 M sodium hydroxide solution exhibited an excellent photocatalytic performance owing to the suitable vacancy concentration. Superoxide free radicals instead of hydroxyl radicals took the important role in the photodegradation process. [ABSTRACT FROM AUTHOR]

Acid fracturing and hydraulic fracturing are two useful methods to improve productivity of geothermal wells. Compared with hydraulic fracturing, it remains challenging to select and design an optimal scheme of acid fracturing in geotherm reservoirs due to the complex chemical reactions between acidizing fluids and reservoir rocks. A modeling framework for the coupled thermal-hydro-mechanical-chemical processes during acid fracturing in carbonatite geothermal reservoirs is developed, which is verified using the published experimental results. Effects of natural and human-controlled factors on efficiency of acid fracturing are investigated through parameter sensitivity analysis. The results show that the two human-controlled parameters including acid concentration and injection rate play an important role in determining propagation area, whereas the acid etching pattern is mainly dependent on natural reservoir parameters including aperture field, reservoir temperature and in-situ stress. The developed modeling framework is successfully applied to simulate a field test of acid fracturing in a geothermal well, Beijing, China. The further follow-up research and limitations of the present study are also addressed. • A coupled THMC modeling method of acid fracturing in geothermal fields is developed. • The roles of natural and human factors in efficiency of acid fracturing are studied. • The modeling method successfully predicts the results of acid fracturing field test. [ABSTRACT FROM AUTHOR]

In this article, we report theoretical and design studies on the application of an electrostatic potential depression (EPD) on two types of traditional microwave sources, the klystron and the inductive output tube (IOT), both operating in the UHF band. The EPD is implemented by a section of the metallic beam pipe on which a direct current (dc) negative high voltage is applied. Inside the EPD section, the modulated electron beam develops into bunches over a very short longitudinal distance, indicating a possible design approach for a compact device. With the application of an EPD, the peak value of the first harmonic current in a microwave tube can be further increased compared to that in a conventional design, suggesting higher circuit efficiency. As the electron beam leaves the EPD section, the reacceleration of the beam provides a longitudinal cooling effect. With the addition of an EPD, circuit power extraction efficiency above 80% is achieved in both the modified design of the IOT and the novel conceptual circuit design of the klystron. [ABSTRACT FROM AUTHOR]

The major pathological mechanisms of osteoarthritis (OA) progression include inflammation, autophagy, and apoptosis, etc. Moderate mechanical strain and exercise effectively improve chondrocyte degeneration by reducing these adverse factors. Mitofusin 2 (MFN2) is a crucial regulatory factor associated with inflammation, autophagy and apoptosis, and its expression is regulated by exercise. This study aims to elucidate the effects of moderate mechanical strain and exercise on MFN2 expression and its influence on OA progression. Destabilization of the medial meniscus (DMM) surgery was performed on rats to induce an OA rat model. Subsequently, adeno-associated virus (overexpression/knockdown) intra-articular injection or moderate treadmill exercise was administered to evaluate the effects of these treatments on MFN2 expression and OA progression. Overexpressed plasmids and siRNA vectors were used to regulate MFN2 expression in chondrocytes. An inflammatory degeneration cell model was generated by IL-1β stimulation. Moderate mechanical strain was applied to MFN2-overexpressing cells to explore their interactions. MFN2 overexpression aggravated inflammation by activating the NF-κB and P38 pathways and induced excessive autophagy by inhibiting the PI3K/AKT/mTOR pathway, thereby causing chondrocyte apoptosis and metabolic disorder. Moderate mechanical strain partially reversed these adverse effects. In the DMM rat model, MFN2 overexpression in articular cartilage exacerbated OA progression, whereas MFN2 knockdown and treadmill exercise alleviated cartilage degeneration, inflammation, and mechanical pain. MFN2 is a critical factor mediating the association between inflammation and excessive autophagy in OA progression. Moderate mechanical strain and treadmill exercise may improve OA through downregulating MFN2 expression. This study may provide a theoretical basis for exercise therapy in OA treatment. [Display omitted] • MFN2 is a critical factor in mediating the association between inflammation and excessive autophagy in OA progression. • Moderate treadmill exercise effectively improves OA progression by downregulating MFN2 in the cartilage. • Moderate mechanical strain relieves inflammation by inhibiting the NF-kB and P38 pathways. • Moderate mechanical strain alleviates excessive autophagy by restoring the PI3K/AKT/mTOR pathway. [ABSTRACT FROM AUTHOR]

Drilling of polar deep ice cores is an important means to study the evolution of the earth's climate. When drilling into complex formations such as brittle ice layer, warm ice layer, basement meltwater layer, or ice-rock interlayer, drilling problems frequently occur, especially the hydraulic cracking of ice holes. This paper studies the dynamic propagation process and the influence mechanism by theory and simulation to solve the problem of cracks initiation and propagation around the ice hole. Based on continuum mechanics, a stress model is established to obtain the stress state around the borehole well. In local continuum mechanics, the stress state is represented by spatial partial differential equations, and its spatial partial derivatives cannot describe the discontinuous situation. Peridynamics (PD) use integral equations to solve this problem effectively. The PD model of the ice hole is established to realize the unified description of the continuous and discontinuous space around the ice hole. The dynamic cracks propagation process, the influence mechanism of hydraulic pressure and fracture toughness are analyzed. The loading rate of ice in the paper and experiment is 0.008 mm/s, the elastic modulus is 9 GPa, and the basic fracture toughness is 175 kPa·m0.5. Case study shows that hydraulic pressure promotes cracks propagation, the hydraulic pressure increases by 1 MPa, the volume ratio of cracks increases from 7.67% to 14.93%. The volume ratio of cracks is defined: the ratio of the cracks volume to the total model volume. Fracture toughness hinders cracks propagation, which increases from 150 kPa·m0.5 to 175 kPa·m0.5, the proportion of cracks volume decreases from 13.85% to 7.67%. When drilling into the formation with prominent ductile-brittle transition, the mud density shall be adjusted in time to control the hydraulic pressure in the hole to reduce cracks propagation and ensure the safety and efficiency of ice drilling. [ABSTRACT FROM AUTHOR]

To enhance the performance of Li‐ion batteries, hierarchical carbon‐based hollow frameworks embedded with cobalt nanoparticles are prepared by the pyrolysis of core‐shell ZIF‐8@ZIF‐67 polyhedrals prepared via a seed‐mediated growth method. The resultant hollow frameworks are composed of the N‐doped carbon as the inner shells and the porous graphitic carbon embedded with cobalt nanoparticles as the outer shells. Benefiting from the unique hollow architecture with large surface area and good electrical conductivity, the electrode materials exhibit good electrochemical performance with improved specific capacities, high‐rate capability, and good cycling stability for Li‐ion batteries. More importantly, the quantitative kinetic analysis reveals the crucial contributions of N doping and the porous structure of graphitic carbon with cobalt nanoparticles for boosting the performance of carbon‐based materials. The rational design of the unique carbon‐based architecture and the understanding of the underlying mechanism for the charge storage process are crucial to construct advanced carbon‐based materials for high‐performance Li‐ion batteries. [ABSTRACT FROM AUTHOR]

Pyrazine is a kind of compound containing pyrazine ring structure, which has attracted the attention of researchers because of its special aroma and healthcare function. It is currently used in spices, pharmaceuticals, food additives, and other industries. Human serum albumin (HSA) is a transport and storage protein in the human circulatory system. Previous research reported that pyrazine can interact with albumin, but the interaction between pyrazine and HSA has not been reported. Consequently, this study is based on the multispectral method and molecular dynamics (MD) simulation, exploring the interaction between different pyrazines and HSA. The results show that the four pyrazines mainly quench the endogenous fluorescence of HSA through the static quenching mechanism. Molecular docking indicates that hydrophobic forces play a major role in the binding of pyrazines with HSA. At the same time, synchronous fluorescence spectroscopy, circular dichroism (CD), three-dimensional fluorescence spectroscopy, and resonance light scattering (RLS) showed that each pyrazine compound can change the conformation of HSA. MD simulation results show that the combination of four pyrazines and HSA can enhance the stability of HSA. Among them, 2,3,5,6-tetramethylpyrazine (TTMP) and 2,3,5-trimethylpyrazine (TMTP) binding is the most stable and the most unstable combination with HSA, respectively. In addition, the four pyrazines could affect the physiological activity of HSA. This study is of great significance to explore the mechanism of action of pyrazine compounds in vivo and can provide useful information for the application of pyrazine compounds in food. [ABSTRACT FROM AUTHOR]

High‐temperature thermochemical energy storage based on metal oxides is the key technology to reducing the levelized costs of electricity of the next‐generation concentrated solar power plants. CuO/Cu2O has wide availability and high energy density, but severe sintering leads to low reactivity. In this study, an innovative approach to modulate the oxygen vacancy content to change the surface properties and crystal structure to enhance the sintering resistance and redox reversibility is proposed. The re‐oxidation degree is increased from 46% to 99%, and the energy release rate is increased by 3.5 times. It remains 99.9% reduction and 97.1% oxidation activity after 3000 cycles, which is very valuable for engineering applications. Cu2MgO3 and Mg0.78Cu0.22O are prone to form oxygen vacancies, which promotes the formation of porous structures. Mg0.78Cu0.22O helps Cu2MgO3/CuO/Cu2O deliver more O through the surface. Mg0.78Cu0.22O is firmly and uniformly dispersed on the CuO/Cu2O surface after long cycling. They have a large binding energy, more charge transfer and enhanced bond energy at the interface. The mechanism of composite in increasing the sintering temperature and long‐term reaction stability is revealed from experimental and theoretical calculations, which provides a new idea for the rational design of thermochemical energy storage materials. [ABSTRACT FROM AUTHOR]

In this paper, we focus on the rendezvous problem of discrete-time multi-agent systems. Each agent is equipped with the same sensing, computing, and motion-control capabilities to achieve rendezvous based on the neighbors' states. First, a convex hull combination algorithm (CHCA) is designed, in which each agent solves a convex problem composed of perceived neighbors in the sensing region and chooses an optimal control strategy to move to the next position with guaranteed connectivity under low-density network topologies. Second, the relative neighborhood graph is incorporated into the CHCA (RNCHCA) as the constraint set to adapt to the high-density network topologies. The convergence and connectivity of the proposed algorithms are proved based on the geometric concept and case analyses. Finally, a large number of simulation results show that under the initially connected topologies with different densities, the RNCHCA can achieve a higher rendezvous speed than that achieved by the traditional circumcenter algorithm, particularly under high-density network topologies. [ABSTRACT FROM AUTHOR]

The variation of mutual-inductance is the essential reason for fluctuation of transmission power and efficiency during wireless power transfer (WPT) misalign. To maintain output power stability, current methods, such as primary regulation, secondary conversion, magnetic coupling mechanism (MCM) optimization, and compensation topology design, have not changed the characteristic of mutual-inductance changing with misalignment. A strong misalignment tolerance WPT system based on the influence of high permeability magnetic materials on equivalent electrical parameters of MCM is proposed. When the primary and secondary sides of MCM shift, the relative distance between magnetic shielding and coil (RDMSC) is adjusted to maintain the stability of mutual-inductance. The transmission efficiency and power are not affected by misalignment. Alternatively, RDMSC can be actively adjusted to meet the various needs of diverse loads at different times. Simulations and experiments are conducted. The effectiveness of the proposed scheme that RDMSC is actively adjusted to overcome misalignment is verified. This is a new method based on active adjustment of spatial electromagnetic coupling, which provides a new idea for WPT to overcome the influence of misalignment and maintain stable output. [ABSTRACT FROM AUTHOR]

Hulless barley (HB) grass is a potential resource of functional food. In this study, the proliferation inhibitory effect against cancer cells of an alkaline extracted polysaccharide (APP) from HB grass (HBG) is analyzed. The yield of crude alkaline extracted polysaccharide (APC) reaches 15.1%. After purification, the purity and polydispersity index (PDI) of the APP are 98.3% and 1.38, respectively. The molecular weight of APP is 5.1 × 105 Da, whereas the number‐average molecular weight of APP is 3.7 × 105 Da. APP is composed of arabinose (37.8%), xylose (41.3%), glucose (4.6%), and galactose (16.3%). According to the infrared spectral analysis, APP is found to contain β‐glycosidic bonds. Moreover, APP possesses significant cell proliferation inhibitory effects against various cancer cell lines, such as 4T1, HT29, Caco‐2, and CT26.WT in a dose‐dependent manner. Notably, the IC50 value of 4T1 reaches 7.56 mg mL−1, which indicates that APP from HBG has a potential anti‐cancer effect in vitro. It may be further investigated as an ingredient or nutraceutical for development and utilization in functional foods to prevent or treat cancer and related diseases. [ABSTRACT FROM AUTHOR]

It is known that pre-existing discontinuities can act as planes of weakness that divert the propagating fractures in rocks, but previous studies have mostly focused on the interaction between the propagating fractures and a single pre-existing discontinuity. The influences of multiple pre-existing cemented discontinuities, such as calcite veins and bedding planes, on the fracture propagation still remain poorly understood. In this study, particle-based discrete element method was used to characterize the fracturing behavior of shale containing multiple cemented veins and bedding planes through numerical semi-circular bend (SCB) tests. Model results show that geometrical and mechanical properties of multiple pre-existing cemented discontinuities can significantly affect the interaction modes between the induced tensile fractures and pre-existing cemented discontinuities, as well as the mode I fracture toughness of shale. The typical mechanical interaction modes between the induced tensile fractures and the multiple pre-existing cemented discontinuities and the corresponding conditions are given. The effect of pre-coexisting discontinuities on the peak loads for shale during SCB tests is also discussed. [ABSTRACT FROM AUTHOR]

• The first 2D combined CH4-assisted SOEC and F-T synthesis model is developed. • A novel strategy towards low-carbon fuel generation is proposed. • Parametric studies are conducted with performance determining factors discussed. • The distribution of generated carbon-contained fuels (from C 1 to C 5+) is studied. CH 4 -assisted solid oxide electrolyzer cells (SOECs) can co-electrolyze H 2 O and CO 2 effectively for simultaneous energy storage and CO 2 utilization. Compared with conventional SOECs, CH 4 -assisted SOECs consume less electricity because CH 4 in the anode provides part of the energy for electrolysis. As syngas (CO and H 2 mixture) is generated from the co-electrolysis process, it is necessary to study its utilization through the subsequent processes, such as Fischer-Tropsch (F-T) synthesis to produce more value-added products. An F-T reactor can convert syngas into hydrocarbons, and thus it is very suitable for the utilization of syngas. In this paper, the combined CH 4 -assisted SOEC and F-T synthesis system is numerically studied. Validated 2D models for CH 4 -assisted SOEC and F-T processes are adopted for parametric studies. It is found that the cathode inlet H 2 O/CO 2 ratio in the SOEC significantly affects the production components through the F-T process. Other operating parameters such as the operating temperature and applied voltage of the SOEC are found to greatly affect the productions of the system. This model is important for understanding and design optimization of the combined fuel-assisted SOEC and F-T synthesis system to achieve economical hydrocarbon generation. [ABSTRACT FROM AUTHOR]

• The first 2D hybrid model combining photoreactor and SOFC is developed. • A novel strategy towards power generation from solar energy is proposed. • Zero CO 2 emission can be achieved during the operation of proposed system. • Parametric studies are conducted with performance determining factors discussed. Solar fuels, as clean and sustainable fuels, are promising energy sources for future low carbon economy. In this work, a hybrid system consisting of a photoreactor and a solid oxide fuel cell (SOFC) is proposed for on-site power generation from solar fuels. 2D numerical models are developed for the hybrid system for the first time by coupling the mass/momentum transport with the charge (electrons/ions) transport and the electrochemical/chemical reactions. A peak power density of 2162 W m−2 is achieved from the SOFC at 1073 K operating temperature. However, a rapid drop of the power density is observed at large current density due to the fuel starvation in the anode. The inlet CO 2 mole fraction is found to significantly affect the output power density of the SOFC and CO 2 utilization rate of the photo reactor, where a CO 2 mole fraction of 40% is the optimum value for the studied cases. The results offer insightful information on energy conversion from solar to fuel to power and provide new options for sustainable energy conversion devices. [ABSTRACT FROM AUTHOR]

Highlights • A 2D thermal model of ethanol fuelled SOFC is developed. • High conversion ratio of ethanol to CO and H 2 are achieved. • The water to ethanol ratio should be higher than 3 to prevent carbon deposition. • Effects of applied voltage and inlet fuel temperature are studied. Abstract A 2D thermal model is developed to investigate an ethanol-fuelled Solid Oxide Fuel Cells (E-SOFC) with a Ni-ZrO 2 /CeO 2 functional layer for internal reforming of ethanol. The catalytic kinetics of the functional layer used in this model is validated in terms of ethanol conversion and product selectivity in the experimental data of a fixed-bed testing reactor. The simulated E-SOFC demonstrates a typical performance of 4385.6 A m−2 at 0.6 V, corresponding to a power density of 2631.4 W m−2, with a high conversion ratio of ethanol (0.903) at 700 °C. Parametric studies of voltage, water to ethanol ratio and inlet fuel gas temperature are conducted and comprehensively analysed, concluding that the positive effects of lowering the voltage and increasing the inlet temperature on the ethanol conversion. We find that adding the reforming layer is a facile and effective way to replace the conventional H 2 by abundant-in-nature ethanol for SOFC from the numerical analysis. Attention is also drawn to the carbon deposition risk by thermodynamic analysis of the gas composition, suggesting to keep the water to ethanol ratio higher than 3. The as-developed model can serve as an effective tool for the optimization of the operating conditions and geometry design to avoid carbon deposition and improve the performance of ethanol-fuelled Solid Oxide Fuel Cells. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights: • Numerical models are developed for all porous solid oxide fuel cells. • Electrolyte porosity changes are investigated for the solid oxide fuel cells. • Criterion of safe operations are considered in the simulation. • Effects of operating parameters for the solid oxide fuel cells are studied. • A novel design is proposed to improve the performance of solid oxide fuel cells. Abstract Conventional solid oxide fuel cells (SOFCs) could suffer from carbon deposition when fueled with hydrocarbons. For comparison, a new type of SOFC with porous electrolyte can resist carbon deposition because it allows oxygen molecules to transport from the cathode to the anode. As the transport of O 2 to the anode lowers the fuel cell performance and causes the risk of explosion, the rate of O 2 transport must be well controlled to ensure efficient and safe operation. Following our previous model, this paper focuses on electrolyte porosity optimization under various inlet methane mole fractions, inlet oxygen mole fractions and inlet gas flow rates. Furthermore, a new design with a partial porous electrolyte is proposed and numerically evaluated. The new design significantly improves the electrochemical performance compared with all-porous one. A conversion rate >90% from methane to syngas is achieved at the 0.33 inlet CH 4 mole fraction with the new design. The results enhance the understanding of all porous solid oxide fuel cells and the mechanism underlying, inspiring novel designs of solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

A novel integrated system consisting of an external heat source, a direct carbon solid oxide fuel cell (DC-SOFC), a vacuum thermionic generator (VTIG) and a regenerator is proposed to handle the heat management of the DC-SOFC. The electrochemical/chemical reactions, ionic/electronic charge transport, mass/momentum transport and heat transfer are fully considered in the 2D tubular DC-SOFC model, which shows that the overall heat released in the cell is always different from the heat required by the internal Boudouard reaction. Three different operation strategies of the proposed system are presented, and accordingly, analytical expressions for the overall power output and efficiency for the proposed system are specified. The results show that the VTIG could effectively recover the waste heat for additional power production at a large operating current density, and the maximum power density and efficiency of the proposed system could reach more than 8100 W m −2 and 60% at 30,000 A m −2 and 1173 K, respectively. The effects of the operating current density, the operating temperature and the distance between the carbon layer and anode of the DC-SOFC, and the size, anode temperature and work function of the VTIG on the performance of the proposed system are discussed through comprehensive parametric studies. [ABSTRACT FROM AUTHOR]

A new combined system model is proposed to numerically assess the feasibility and effectiveness of using a thermophotovoltaic cell (TPVC) for waste heat recovery from a direct carbon solid oxide fuel cell (DC-SOFC). The system model mainly consists of an irreversible TPVC model and a 2D tubular DC-SOFC model considering the ionic/electronic charge transport, mass transport, momentum transport, and chemical/electrochemical reactions. Mathematical expressions of the power density and efficiency for the proposed system are derived and the performance characteristics of the combined system are revealed. The impacts of operation conditions and designing parameters including the operating temperature of the DC-SOFC, distance between the carbon layer and anode, and band-gap energy of the TPVC on the combined system performance are examined. It is found that the TPVC can efficiently harvest the waste heat from the DC-SOFC. The maximum power density of the combined system is approximately 56.2% larger than that of the stand-alone DC-SOFC. Moreover, a higher operating temperature of the DC-SOFC and a smaller distance between the carbon layer and the anode are beneficial to the performance enhancement of the combined system. The power density of the combined system can be further improved through designing the TPVC with an optimum band gap. [ABSTRACT FROM AUTHOR]

A tubular proton conducting solid oxide fuel cell (H-SOFC) integrated with internal dry methane reforming (DMR) layer is numerically studied for power and syngas cogeneration using CO 2 and CH 4 as fuel by the Finite Element Method. The coupled heat and mass transporting with electrochemical reactions and chemical reactions (DMR, water gas shifting reaction and methane steam reforming) are fully considered. The model is substantially validated with experimental data of DMR catalyst characterization and SOFC button cell electrochemical characterization. The base case analyses are conducted at open circuit voltage (OCV) and 0.7 V of the DMR-SOFC. It is found that the CO 2 conversion and CH 4 conversion can be increased by 4.8% and 21.6%, respectively, by increasing the operating voltage of DMR-SOFC from OCV to 0.7 V, with the coproduction of electricity (1.5 W). These conversion enhancements were caused by the in-situ integration of the endothermal DMR reaction and exothermal H 2 electrochemical oxidation. Effects of operating voltage and inlet flow rate of feeding gas are evaluated. The voltage is suggested to be higher than 0.5 V to avoid large temperature gradient in the reactor. It is also found that conversion ratios of both CH 4 and CO 2 decrease from over 90% to be below 60% as the fuel flow rate is increased from 40 cm 3  min −1 to 80 cm 3  min −1 . [ABSTRACT FROM AUTHOR]

Cavitation, biofouling, and seawater corrosion are important factors that reduce the service life of propellers and other overcurrent components of ship. Herein, OH-PDMS was introduced into polyurethane and a series of hydrophobic polyurethane coatings (SiPU-X) with anti-cavitation, antifouling and anticorrosion functions were synthesized by a simple addition reaction. The chemical composition and microstructure of the prepared coatings were analyzed by means of FT-IR, SEM, and EDS, and it was found that the addition of OH-PDMS enhanced the degree of microphase separation of SiPU-X. The addition of OH-PDMS resulted in a large number of island structures of OH-PDMS on the coating surface. The SiPU-15 with the optimal microphase separation had better tensile strength of 12.33 MPa, excellent hydrophobicity (with a contact angle of 105.3°), hydrolysis resistance (with a hydrolysis rate of 0.26 %), and water repellency (with a water absorption of 2.21 %). More importantly, the weight loss (7.1 mg) of SiPU-15 was much lower than that of SiPU-0 (10.0 mg) under 60 h cavitation owing to the suitable microphase structure on the surface. In addition, SiPU-15 exhibited excellent fouling release properties and could remain in the ocean for 60 days without microbial adhesion. The |Z| 0.01Hz of SiPU-15 can maintain 3.33 × 107 Ω·cm2 after immersion in 3.5 wt% NaCl for 10 days. This work provides a heuristic perspective on the design of polymer materials with cavitation, fouling, and corrosion resistance performance. [Display omitted] • SiPU-X is prepared by introducing OH-PDMS into polyurethane. • The optimum degree of microphase separation is SiPU-15. • The weight loss of SiPU-15 is 7.1 mg under 60 h cavitation. • SiPU-15 is not attached to macroscopic organisms after 60 days of immersion in the real marine environment. • The log|Z| 0.01Hz of SiPU-15 can maintain 7.5 Ω·cm2 after immersion in 3.5 wt% NaCl for 10 days. [ABSTRACT FROM AUTHOR]