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As the foundation of circuits and electronic systems, the quality of printed circuit boards (PCBs) is directly related to the reliability of the whole system. At present, deep learning-based target detection technology has a broad application prospect in PCB defect detection. However, there are still some shortcomings in the process of detection. For example, the detection speed is slow, and the detection accuracy is not ideal for defects with small size. Therefore, this paper proposes an improved algorithm based on the YOLOv5s model to improve the detection of PCB defects. The algorithm enhances the connection between the shallow and high layers of the network by improving the backbone network structure. Meanwhile, a self-attention mechanism is introduced into YoloHead to enhance the feature extraction and the ability to focus on the global information of the feature map, and the self-attention mechanism is optimized by combining the computational characteristics of the SENet, the CBAM and the residual unit. While improving the accuracy of PCB defect detection, better computational efficiency is ensured. In subsequent experiments, this paper trains and tests the improved YOLOv5s algorithm using publicly available PCB defect datasets. The results show that the algorithm achieves a detection rate of 39.7 frames per second and a maximum average precision of 96.14%, which is a 4.68% improvement over the original YOLOv5s. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing has been widely used to enhance reservoir permeability during the extraction of shale gas. As one of the external input parameters, injection rate has a significant impact on formation breakdown pressure and the complexity of hydraulic fractures. To gain deeper insights into the effect of injection rate on breakdown pressure and fracture morphology, we conducted five hydraulic fracturing experiments on Changning shale in the laboratory. We used five different injection rates between 3 and 30 mL/min to fracture cylindrical core samples with 50 mm in diameter and 100 mm in length. We monitored acoustic emissions and surface displacements during the tests, and analyzed the fracture pattern post mortem by using a fluorescent tracer. We find a semi-logarithmic relationship between the breakdown pressure and the injection rates. Second, we find that it is the injection rate that dictates sample deformation and crack formation during breakdown rather than the fluid volume injected during the whole process. The analysis of amplitudes and frequency of acoustic signals indicates that hydraulic fracturing of Changning shale is overall dominated by tensile fractures (> 60%). However, at low injection rates, shear events are facilitated before rock breakdown. On the other hand, high injection rates result in reducing fracture tortuosity and surface roughness due to limited fluid infiltration in the relatively short injection window. We close this study with a conceptual model to explain the difference between fluid infiltration (low injection rates) and the loading rate effect (high injection rate) in low-permeability shale rocks. The findings obtained in this study can help to adjust injection rates in the field to economically and safely produce gas from shale. Highlights: Rock expansion upon breakdown is dominated by instantaneous crack opening caused by injection rates. Low injection rates reduce the breakdown strength by activating shear cracks in a larger fluid infiltration zone. High injection rates have limited effects on fracture morphology. A theoretical model is proposed to elucidate the competing mechanism between fluid infiltration and the loading rate effect. [ABSTRACT FROM AUTHOR]

• Patients with exposed bones or tendons present significant clinical challenges. • Autologous flap transplantation leads to graft failure and tendon adhesion. • Artificial dermis reduces surgical risk and invasiveness. • Emphasis on exploring the potential benefits of artificial dermis. The clinical effects of artificial dermis in treating skin and soft tissue defects accompanied by bone or tendon exposure were assessed. A retrospective analysis was conducted on the clinical data of 45 cases of skin and soft tissue defects accompanied by bone or tendon exposure admitted to the trauma surgery department of Fujian Provincial Hospital between February 2018 and August 2020. They were divided into the artificial dermis and control groups. The wound was assessed using the Vancouver Scar Scale (mVSS), and the postoperative visual analogue scale (VAS) scores were recorded at 3, 6, 9, and 12 months after surgery. At the 12-month after surgery, skin sensation recovery was evaluated using the criteria of the British Medical Research Council (BMRC). The cases included 26 males and 19 females, aged 50 to 85 years. All patients were followed up for an average of 13.8 months (range: 12–18 months). Compared with controls, the wound healing time of the observation group was longer (35.8 ± 10.6 vs. 28.5 ± 4.8, P = 0.007), without significant differences for the number of operations and length of hospitalization. The mVSS scores were not different between groups (P group = 0.294), but the scores decreased with time (P time < 0.001), and the group×time interaction was significant (P interaction < 0.001). Similarly, the VAS scores were not different between groups (P group = 0.667), but the scores decreased with time (P time < 0.001); the group×time interaction was not significant (P interaction = 0.274). At the 12-month mark following the operation, in the artificial dermis group, the MCRR score was S3+ in 23 patients, while it ranged from S0 to S3 in two patients; in the control group, S3+ was observed in 17 patients, and S0-S3 in three (P = 0.815). Artificial dermis treatment is considered a safe and effective alternative therapy for patients with skin and soft tissue defects accompanied by bone or tendon exposure who cannot tolerate or are unwilling to undergo autologous skin flap transplantation. It offers the advantages of minimal donor site trauma, simplicity in operation, and favorable postoperative functional recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • The basalt fiber and gelling effects on mode I/III fracture of mortar were assessed. • The fracture performance is enhanced mainly due to the fiber crack-bridging effect. • The 3D-MTSN criterion is suitable for forecasting mode I/III fracture toughness. The study of the crack resistance of modified cement-based materials can provide a valuable guidance for pavement structural design. In this work, the plain mortars with 3 different water/cement ratios (0.35, 0.45 and 0.55) and the basalt fiber (BF) reinforced mortars with 3 different amounts of basalt fibers (0 %, 0.3 % and 0.8 % by mass) were prepared to investigate mixed mode I/III fracture performance. In the BF reinforced groups, we take the water/cement ratio of 0.45 as a reference. Then, the fracture experiments were conducted using the Edge Notch Disc Bend (ENDB) testing, and the pore structure measurements of each sample were performed using the nuclear magnetic resonance (NMR) testing system. The results show that an appropriate reduction in water/cement ratio and an increase proportion of basalt fibers are both beneficial to improving the fracture performance of the cement mixtures. However, a superior fracture performance was achieved for BF reinforced mortar composites over the mortar with gelling enhancement. For instance, the enhancement rate of applied load, fracture energy, and effective fracture toughness for BF reinforced mortar under mode III are 3.27, 2.35, and 1.34 times the values of those for gelling-enhanced mortar under mode III, respectively. We also find that the three dimensional maximum tangential strain (3D-MTSN) criterion is applicable for predicting mixed mode I/III stress intensity factor (SIFs) of mortar composites. The reduction in water/cement ratio significantly increases the amount of micropores inside the mortar specimen. By contrast, the addition of basalt fibers to the cement mixture deteriorates its pore structure by raising the proportion of macropores to total pores from 3 % to 10 %. However, the basalt fiber crack-bridging effect on improving the fracture toughness of the cement mixtures is also revealed. [ABSTRACT FROM AUTHOR]

Strongly weathered phyllite is a metamorphic soft rock widely distributed in the central and western regions of China. Due to its inadequate engineering properties, the direct use of this material as a roadbed filler is not feasible and requires improvement. In this paper, calcium acetate Ca(CH 3 COO) 2 , magnesium acetate Mg(CH 3 COO) 2 and calcium chloride CaCl 2 are prepared to improve the filler by microbially induced carbonate precipitation (MICP). The effects of different calcium and magnesium sources on porosity, water absorption, uniaxial compressive strength, crack propagation time and failure patterns are investigated. The results show that CaCl 2 and Ca(CH 3 COO) 2 exhibit the most significant enhancement effect in reducing porosity and water absorption, increasing the uniaxial compressive strength by over 30%, delaying the time of failure occurrence and reducing the number of tensile cracks significantly. X-ray diffraction (XRD), scanning electron microscopy (SEM) and pore size distribution analyses reveal disparities among the rock samples. CaCl 2 and Ca(CH 3 COO) 2 have greater efficacy than Mg(CH 3 COO) 2 in terms of improvement, as they generate relatively many carbonate precipitates to bind the phyllite filler and reduce the size and quantity of pores. To avoid the corrosion of Cl- ions when adding reinforcement bars in actual engineering, Ca(CH 3 COO) 2 is an ideal calcium source for improving the strongly weathered phyllite filler. • The physical and mechanical properties of strongly weathered phyllite filler can be improved after modification. • The physical properties and strength of modified sample have a relationship with carbonate content and crystal morphology. • Calcium acetate is suggested for use as the calcium source to improve the strongly weathered phyllite filler. [ABSTRACT FROM AUTHOR]

This paper focuses on the comparative study of vertical and horizontal vacuum membrane distillation (VMD) modules coupled with mechanical vapor recompression (MVR) system to obtain the optimal system layout structure and further improve operation stability and energy efficiency in the wastewater treatment. Firstly, freshwater accumulation characteristic in the vertical VMD module was explored under different working conditions. Then, comparative experiments of vertical and horizontal VMD-MVR systems were conducted. Finally, comprehensive performance of horizontal VMD-MVR system were evaluated. The obtained results showed that freshwater production in the distilling tank and freshwater accumulation in the VMD module were affected by operation time, feed temperature, feed flow rate, feed concentration and vacuum side pressure. Furthermore, the horizontal VMD-MVR system was proved to be a better choice due to lower freshwater accumulation in the VMD module and energy consumption in comparison to the vertical VMD-MVR system. Finally, long term operation experiment of 240 h indicated evaporation rate dropped to 55 kg/h as operation time reached to 180 h owing to membrane fouling. After membrane cleaning, evaporation rate recovered from 55 to 62 kg/h with a higher recovery efficiency of 95.1 %. Compared to conventional wastewater treatment systems, the horizontal VMD-MVR system exhibited excellent comprehensive performance. [Display omitted] • Performance comparison of vertical and horizontal VMD-MVR were conducted. • Freshwater accumulation in the VMD module affected the evaporation rate. • Vertical VMD-MVR system had higher energy consumption than horizontal system. • Separation efficiency of horizontal VMD-MVR system was 99.9 %. • Evaporation rate recovered from 55 kg/h to 62 kg/h after membrane cleaning. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fracture initiation and breakdown pressures are independent of shale heterogeneity. • Deviating bedding planes from axial direction suppresses tensile cracks. • Shale heterogeneity exerts insignificant impact on deformation than bedding anisotropy. Shales are intrinsically anisotropic and heterogeneous due to the existence of bedding planes and natural microfractures. Although the roles of shale bedding anisotropy and inherent heterogeneity have been well studied, their combined effects remain unclear. To fill this knowledge gap, we performed six hydraulic fracturing tests on shales with varying bedding inclinations (0°, 45° and 90°) collected from Changing (Sichuan) and Lushan (Jiangxi), South China. The mineral components and microstructure of shales collected from these two places were compared. The results indicate that the shale from Lushan is more heterogeneous due to its higher content of microfractures and pores than the shale from Changning. Through hydraulic fracturing analysis, we show that the fracture initiation pressure and breakdown pressure first increase and then decrease with increasing bedding inclination, and a strong linear correlation between the two pressures is found to be independent of shale heterogeneity. Second, we find inconsistency between the high breakdown pressure and large hoop deformation, which can be attributed to the anisotropy effect of shale's bedding strength relative to the maximum principal stress. In addition, the analysis of the amplitudes and frequency of acoustic emission signals suggests that tensile cracks preferentially occur in a short-transverse mode, while deviating the bedding plane from the axial direction suppresses the initiation of tensile cracks. Shale heterogeneity is mainly reflected in reducing the magnitude of critical pressures and deflecting local fracture branch behaviors, which are less significant than the impacts of bedding anisotropy during the hydraulic fracturing process. [ABSTRACT FROM AUTHOR]

Unintentional variations of fluid pressure within a hydraulic fracture will disturb the surrounding stress state, affect the stability of fracture propagation and complicate the fracture intersections during the process of hydraulic fracturing. However, little attention has been paid to the effect of nonuniform fluid pressure inside the hydraulic fracture. This paper presents a semianalytical solution for a Griffith crack nonuniformly pressurized by internal fluid in an impermeable elastic plane. The fluid pressure is hypothetically designated as a general polynomial with respect to the location of the fluid, such that the effect of an arbitrary form of fluid pressure distribution can be explored by polynomial fitting. The semianalytical solution is capable of being degenerated into constant pressure forms which confirms that the solution is an extension of classic constant pressure. In addition, the critical propagation conditions and stress distributions (e.g., σxx) under constant and nonuniform pressures are compared and discussed. The comparison results indicate that the effect of nonuniform fluid pressure accumulated by the number of polynomial terms increases the magnitude of stress (or displacement) but does not change its distribution. Subsequently, the semianalytical solution is validated by comparing the fracture intersection predicted by the semianalytical solution with the laboratory experimental observations and published predictions under constant fluid pressure. Good agreement with the experiments and sufficient advantages over previous predictions are observed. Finally, a sensitivity analysis of existing parameters in the semianalytical solution, including crack length, initial pressure, number of terms and number of subintervals, is conducted to evaluate their influence on surrounding stresses and critical propagation conditions, which further demonstrates the applicability and reliability of the presented semianalytical solution. The new solution enriches hydraulic fracturing theory by considering the nonuniform fluid pressure effect and provides important reference for fracture network design during hydraulic fracturing. [ABSTRACT FROM AUTHOR]

• Horizontal borehole reduces fracture initiation and breakdown pressures. • Inclined bedding promotes the formation of flat bedding fractures. • Wellbore oblique to bedding facilitates fracture network formation. • A low injection rate leads to complex fractures and reduces breakdown pressure. A series of hydraulic fracturing experiments were conducted using Lushan shale cores (50 mm in diameter and 100 mm in length) to unravel the formation mechanism of fracture networks under the combined effects of wellbore type (vertical or horizontal well), wellbore orientations relative to the bedding plane (0°, 30°,45°, 60°, and 90°), bedding inclinations (0°, 30°,45°, 60°, and 90°), and injection rates (0.03, 0.3, 3, and 30 mL/min). We monitored acoustic emission and surface displacements during the test and conducted post failure inspection via a fluorescent tracer and a 3D laser scanner. We show that adjusting the maximum principal stress perpendicular to the wellbore is beneficial for reducing the breakdown pressure. Inclined bedding tends to initiate along the bedding plane with relatively low fracture initiation pressure and breakdown pressure. Deploying the wellbore inclined to bedding inclination and/or adopting a low injection rate is beneficial to reduce the shale breakdown strength and create a complex fracture network. However, this will correspondingly increase the fracture surface roughness, which may impede the effective transportation of proppant. These findings can provide an important reference for field hydraulic fracturing. [ABSTRACT FROM AUTHOR]

• The shear-modified Gurson-Tvergaard-Needleman (GTN) model is used to reveal the effect of manufacturing-process-induced porosity on the scatter of ductile fracture properties of a high-pressure die-casting aluminum alloy. • A novel parameter calibration scheme is proposed and validated to overcome this shortcoming of the shear-modified GTN model. • Given the proposed parameters identification strategy, the shear-modified GTN model have been further extended to predict the ductile failure behavior of the investigated porous material in both fracture displacement and fracture location. In this paper, we investigate how the shear-modified Gurson-Tvergaard-Needleman (GTN) model can be used to reveal the effect of manufacturing-process-induced porosity on the scatter of ductile fracture properties of a high-pressure die-casting aluminum alloy. The GTN model exhibits great advantages in predicting the variation of failure strain/displacement by altering the initial void volume fraction (f 0), compared with uncoupled ductile damage models. For a specific metallic material, one unique set of model parameters is usually determined from experiments, which leads to the fact that only a deterministic failure strain/displacement can be obtained under a fixed porosity. To overcome this shortcoming of the shear-modified GTN model, a novel parameter calibration scheme is proposed and validated in the present study. Following the physical background of the GTN model, the twelve material parameters of the shear-modified GTN model have been determined based on a combination of macroscopic mechanical tests covering a wide range of stress states and micromechanics-based unit cell simulations. Different from the existing calibration strategies, the simulation results of unit cells embedded with a spherical void have revealed a mutual dependence between the f 0 and critical void volume fraction (f c). By conducting interrupted shear tests, the evolution of secondary nucleated void volume fraction was identified according to the statistical results of the fractured brittle silicon particles. The remaining parameters have been further iteratively determined. In the end, the effectiveness of the proposed parameter determination approach is confirmed based on the accurate prediction of stochastic ductile failure properties (both the global failure displacements and the local failure patterns) in different fracture tests. Given the proposed parameters identification strategy, the GTN material models have been enriched to predict the ductile failure behavior of metallic materials, which possess relatively high porosities and more pronounced scattering in failure properties. [ABSTRACT FROM AUTHOR]

• We use machine learning models in a relatively large resting-state fMRI data sample. • Functional connectivity predicts the individualized tendency of self-prioritization. • Interaction among default mode, cognitive control, and salience networks contributes. • Some subcortical regions like the thalamus also play an essential role. • Results support the fundamental-self hypothesis and advance a new neural model. Although the self has traditionally been viewed as a higher-order mental function by most theoretical frameworks, recent research advocates a fundamental self hypothesis , viewing the self as a baseline function of the brain embedded within its spontaneous activities, which dynamically regulates cognitive processing and subsequently guides behavior. Understanding this fundamental self hypothesis can reveal where self-biased behaviors emerge and to what extent brain signals at rest can predict such biased behaviors. To test this hypothesis, we investigated the association between spontaneous neural connectivity and robust self-bias in a perceptual matching task using resting-state functional magnetic resonance imaging (fMRI) in 348 young participants. By decoding whole-brain connectivity patterns, the support vector regression model produced the best predictions of the magnitude of self-bias in behavior, which was evaluated via a nested cross-validation procedure. The out-of-sample generalizability was further authenticated using an external dataset of older adults. The functional connectivity results demonstrated that self-biased behavior was associated with distinct connections between the default mode, cognitive control, and salience networks. Consensus network and computational lesion analyses further revealed contributing regions distributed across six networks, extending to additional nodes, such as the thalamus, whose role in self-related processing remained unclear. These results provide evidence that self-biased behavior derives from spontaneous neural connectivity, supporting the fundamental self hypothesis. Thus, we propose an integrated neural network model of this fundamental self that synthesizes previous theoretical models and portrays the brain mechanisms by which the self emerges at rest internally and regulates responses to the external environment. [ABSTRACT FROM AUTHOR]

The temperature distribution inside a low-temperature combustion chamber with circuited flame path during the low temperature pyrolysis of lignite was simulated using the computational fluid dynamics software FLUENT. The temperature distribution in the Uhde combustion chamber showed that the temperature is very non-uniform and could therefore not meet the requirements for industrial heat transfer. After optimizing the furnace, by adding a self-made gas-guide structure to the heat transfer section as well as adjusting the gas flow size in the flame path, the temperature distribution became uniform, and the average temperature (550-650 °C) became suitable for industrial low-temperature pyrolysis. The Realizable k-epsilon model, P-1 model, and the Non-premixed model were used to calculate the temperature distribution for the combustion of coke-oven gas and air inside the combustion chamber. Our simulation is consistent with our experimental results within an error range of 40-80 °C. The one-dimensional unsteady state heat conduction differential equation $$\mathop \rho \nolimits_{coal} \mathop C\nolimits_{coal} \frac{\partial T}{\partial t} = \frac{\partial }{\partial x}(\lambda \frac{\partial T}{\partial x})$$ can be used to calculate the heat transfer process. Our results can serve as a first theoretical base and may enable technological advances with regard to lignite pyrolysis. [ABSTRACT FROM AUTHOR]

Dehydration of lignite primarily occurs in two stages, namely, removal of surface moisture and decrease in oxygen-containing functional groups and moisture stage. Moisture on the lignite surface could be removed at temperatures below 100 °C. However, parts of oxygen-containing functional groups were removed first followed by the removal of the adsorbed moisture at temperatures in the range 100–300 °C. Dehydration time increased with an increase in the dehydration load and heat transfer distance. At surface moisture of 7 wt.%, temperature of lignite increased rapidly. Higher temperature of combustion chamber yielded shorter removal times for surface moisture and oxygen-containing functional groups. Based on the rate of increase of lignite temperature and associated heat transfer process, coking chamber could be divided into three zones: the near, middle, and remote zones. The near zone temperature curve was determined to be a convex function ∂ 2 T ∂ τ 2 ≤ 0 ; however, the middle zone temperature curve was determined to be a concave function ∂ 2 T ∂ τ 2 ≥ 0 ⋅ ∂ 2 T ∂ τ 2 = 0 and ∂ T ∂ τ = k were the boundary indices of the middle and remote zones. 100 °C isothermal surface movement rate was found to be affected by the heat transfer capacity and dehydration load. Center temperature distribution of coking chamber was made uniform by steam, and temperature of HM 7% was the most uniform distribution. [ABSTRACT FROM AUTHOR]

This paper aims to determine the distribution of all species produced from Zhaotong lignite under low temperature pyrolysis and to derive an appropriate kinetic model. A fixed bed reactor system with no carrier gas is used. For the products (tar, gas and semi-char) distribution determination, experiments are carried out over different operating factors. The characteristics of pyrolysates are analyzed with Gas Chromatograph (GC), Gas Chromatograph/Mass Selective Detector system (GC/MSD), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption–desorption isotherm analysis and Scanning Electron Microscope (SEM). The kinetic model of Coats–Redfern is used, as a basis, to predict the experimental evolution curves. It is seen here that temperature, heating rate and particle size play a pivotal role in low temperature pyrolysates distribution. Meanwhile, it is suggested that atomic ratios of H/C and O/C have some correlativity with the yield of products. The prediction of Costs–Redfern integral model is discussed with the experimental fractions, which indicates that the model is suitable to explain the reaction mechanism of lignite during low temperature pyrolysis. [ABSTRACT FROM AUTHOR]

Highly efficient industrial carbonization furnace with a width of 500 mm was established in this study. The characteristics involving temperature increase, variation rules for the thermal conductivity of coal, and the temperature distribution model of the coking chamber in a low temperature carbonization process of lignite performed in the furnace were studied. The results showed that the temperature profile of coking chamber could be divided into three zones: the near, middle, and remote zones. The distinguishing index between near and middle zones was a low-temperature-constant (80–100 °C) stage. ∂ 2 T ∂ t 2 = 0 , ∂ T ∂ t = n were the distinguishing indices between the middle and remote zones. When the lignite was carbonized in a single heat source furnace wall coking chamber, the temperature distribution followed the Chen–Clayton equation. Moreover, the effective thermal conductivity coefficient of coal was affected by the carbonization time and heat transfer distance, which exhibited a unimodal distribution during the carbonization process. Furthermore, the classic one-dimensional unsteady temperature distribution model with heat resource factor and the correction equation of heat temperature thermal conductivity were established. After being corrected, the calculated temperature curve was consistent with the measured temperature curve. The model was confirmed by the residual analysis and the error points were in well agreement with the normal distribution. [ABSTRACT FROM AUTHOR]

The pyrolysis characteristics and kinetics of two Chinese low-rank coal samples have been studied through thermogravimetric technique and mathematical modeling. Applicability of three kinetic models, viz. the Doyle temperature integral model, Achar-Brindley-Sharp-Wendworth (ABSW) derivative model and Coats-Redfern integral model, is evaluated. The results showed that Doyle model and ABSW model cannot describe the pyrolysis process accurately, while Coats-Redfern integral model was appropriate to describe pyrolysis reaction of the two low-rank coals. From the Coats-Redfern integral model, the reaction order of low-rank coals was of n = 2, and the pyrolysis process can be divided into four stages; the activation energy decreased with increasing heating rate above 20 K min and increased continuously with the coalification degree. [ABSTRACT FROM AUTHOR]

Data-driven mechanical fault diagnosis has been successfully developed in recent years, and the task of training and testing data from the same distribution has been well-solved. However, for some large machines with complex mechanical structures, such as reciprocating pumps, it is often not possible to obtain data from specific sensor locations. When the sensor position is changed, the distribution of the features of the signal data also changes and the fault diagnosis problem becomes more complicated. In this paper, a cross-sensor transfer diagnosis method is proposed, which utilizes the sharing of information collected by sensors between different locations of the machine to complete a more accurate and comprehensive fault diagnosis. To enhance the model's perception ability towards the critical part of the fault signal, the local attention mechanism is embedded into the proposed method. Finally, the proposed method is validated by applying it to experimentally acquired vibration signal data of reciprocating pumps. Excellent performance is demonstrated in terms of fault diagnosis accuracy and sensor generalization capability. The transferability of practical industrial faults among different sensors is confirmed. [ABSTRACT FROM AUTHOR]

Al–Si alloys fabricated by high-pressure die casting (HPDC) have a broad range of applications. Tailored microstructures of HPDC Al–Si alloy were continuously put forward to fulfill the increasing demand for mechanical performance of components. This paper attempts to build microstructure-property relationships of high-pressure die-casting Al–Si alloy to fulfill the increasing demand for mechanical performance of components by tailoring initial microstructure. Moreover, develop a scale-bridging approach to quantitatively upscale the damage initiation of Al–Si alloy under various stress states from micro to macro scale. Both finite element (FE) simulations and Fast Fourier transform (FFT) simulations were applied to calibrate the crystal plasticity parameters. Stress-strain curves simulated by representative volume elements subjected to periodic boundary conditions were validated with the experimental results from uniaxial tensile tests. The response surface design method was herein adopted to rationally and systematically reveal the impact of microstructural heterogeneity on mechanical properties. Finally, damage initiation curves of porous RVEs with distinct characteristics are acquired in terms of the definition of microstructural inhomogeneity criterion. In conclusion, simulation results suggested that strength-related properties are more relevant to the silicon phase characteristics, whereas strain localizations within RVE are observed in the vicinity of pore phase. Furthermore, the predicted failure displacement indicates a good agreement with the experimental results of macro tensile tests. The damage initiation strain shows significant dependence on the stress states and pore phase features (size, volume fraction and morphology). [ABSTRACT FROM AUTHOR]

The structural characteristics of carbonized anthracite briquettes (CAB) obtained at different pyrolysis temperatures were studied by surface area measurements, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The results indicated that the pyrolysis of the anthracite briquette mainly included the following three processes: drying, decomposition and bonding-repolymerization. The total pore volumes and surface areas of the CAB reached maximum values at 500 °C and decreased at higher temperatures. The side chains were removed during pyrolysis, leaving the CAB enriched with polyaromatics. The original oriented anthracite crystallites were deposed, and the microcrystalline planar size L a underwent a prominent decrease before 700 °C. When the pyrolysis temperature rose to 900 °C, the higher pyrolysis temperature and more open structure of the briquette promoted the repolymerization of free radicals, and the value of L a increased from 9.03 to 14.60. The variation of L a correlated well with the mechanical strength of the CAB. The major change in L a in the bonding-repolymerization process revealed stronger interactions between the binder and the anthracite, which improved the quality of the CAB. [ABSTRACT FROM AUTHOR]

• The microstructure and ductile fracture characteristics of the aluminum alloy (Aural-2) produced by high-pressure die casting have been thoroughly characterized via experimental and numerical approaches. • Stochastic ductile fracture property observed over a wide range of stress states of the studied material could be captured by the proposed classic ductile damage model in combination with the probabilistic function. • Simulation results of 3D synthetic finite element models indicate that the global failure strain and the local crack propagation path can be precisely predicted using the calibrated probabilistic damage mechanics model. The microstructure and ductile fracture characteristics of the aluminum alloy (Aural-2) produced by high-pressure die casting have been characterized via experimental and numerical approaches. The stochastic distribution of casting defects (i.e., initial porosity), which is measured by X-ray tomography, leads to a pronounced scatter in the ductile fracture properties of the alloy. Numerical investigations on the ductile fracture behavior have revealed a considerable stress triaxiality dependence of fracture initiation strain, whereas the Lode angle parameter has only marginal effects on the ductile fracture behavior in this material. A probabilistic damage mechanics model is put forward to depict the apparent stochastic ductile fracture behavior over a wide range of stress states. Detailed calibration and validation of model parameters are elaborated in comparison with experimental results. As a further application of the calibrated probabilistic damage mechanics model, the deformation and fracture behavior of heterogeneous structures containing defects has been simulated. Simulation results have confirmed that the variation of initial porosity in different specimens is one of the dominating factors attributed to the observed scatter of failure strain. When the calibrated fracture criteria are applied to simulate the deformation of synthetic porosity-containing finite element models, both the global failure strain and the local crack propagation path can be precisely predicted. [ABSTRACT FROM AUTHOR]

Highlights: [•] Lignite quality improving. [•] Low-temperature pyrolysis. [•] Gaseous products evolution characteristics. [ • ] Morphological characteristics. [Copyright &y& Elsevier]

Carbon nanotubes were successfully synthesized by Fe-K catalytic pyrolysis of coal. The co-pyrolysis of coal and ferrocene can only form fewer carbon nanotubes due to the few available carbon sources. Potassium carbonate can significantly eliminate the defects in the plane between the basic structural units of coal and promote the formation of carbon nanotubes, but its catalytic graphitization effect was limited when potassium carbonate was dry mixed with coal. In addition, the results show that Fe and K had a synergistic effect. Fe atoms and C atoms formed Fe-C solid solution during pyrolysis, K-based catalyst etched amorphous carbon atoms of coal, and finally Fe-K co-catalyzed the growth of a large number of carbon nanotubes with a higher degree of graphitization. The catalytic pyrolysis process had great impact on the aromatic structure and oxygen-containing functional group structure, but slight impact on the aliphatic structure of coal. The molten state of the catalyst during pyrolysis and its affinity for amorphous carbon was higher than that of graphitic carbon, leading to the migration of the catalyst and the change of crystal plane, which may be the reason for the formation of "carbon nanofiber-tube". [Display omitted] • Coal-based carbon nanofibers/tubes were successfully synthesized by Fe-K catalyst. • Fe and K catalysts had a synergistic effect during the process of catalytic pyrolysis. • Catalytic pyrolysis has a greater impact on the aromatic structure and oxygen-containing functional groups of coal. • The "carbon nanofiber-tube" combination structure was discovered, and its formation mechanism was discussed. [ABSTRACT FROM AUTHOR]

• Constant pressure injection condition prolongs hydraulic fracture extension period. • Undulated and complex fractures are favored with the increase of output pressure. • Fracture behaviors are closely correlated with pumping parameter variation. • The fracturing process is characterized by cyclical variation in pumping parameters. • A model is presented to correlate the fracturing process with parameter variations. Field monitoring of hydraulic fractures is currently expensive, and the recorded data is often limited to reflect fracture networks, implying the necessity of utilizing additional evidence to document the fracture propagation state. This paper investigated the relationship between fracture behavior and pumping parameters (pressure and injection rate) by performing laboratory fracturing experiments under constant pressure injection mode (P con = 17, 19, and 21 MPa). In addition, microscope observation and CT scanning imaging were employed to visually investigate the morphological characteristics of fractures on the surfaces and the internal structures of the tested specimens. The results demonstrate that compared to constant flow injection, the constant pressure injection condition prolongs the fracture extension period after crack initiation and results in more significant changes in the pumping parameters and more tortuous morphology in hydraulic fractures. As the constantly injected pressure increases, more complex pumping pressure curves and undulated fractures with dendritic branches were observed. Combining the pumping pressure curves with the fracture behavior during the fracturing process, we found that fracture initiation, arrest, stable propagation, and unstable propagation are closely correlated to the variations of pumping pressure, injection rate, and pressure decay rate, which indicates the reliability of using pumping parameters to reflect the hydraulic fracturing process. Finally, a conceptual model based on wave-like theory was proposed to characterize the constant pressure injection fracturing process and correlate it with the cyclic variation of pumping parameters. The findings are instructive to control the formation of complex fracture networks and provide an essential reference for field treatment design. [ABSTRACT FROM AUTHOR]

Abstract: Carbon dioxide reforming of methane over different semi-cokes (Hongce lignite, Shenmu bituminous coal and Jincheng anthracite) is being investigated at atmospheric pressure, temperature of 800–1000 °C, CH4/CO2 ratios of 3:1–1:3 and gas–solid contact times of 0.11–1.76 min using a fixed-bed reactor. The semi-cokes still shows stable catalyst activity after 480 min of reaction. The results show that the catalyst activity of the semi-cokes was lower with increasing coal rank. The order of the catalyst activity is Hongce lignite semi-cokes > Shenmu bituminous coal semi-cokes > Jincheng anthracite semi-cokes. This is somewhat related to the content of the functional groups of the semi-cokes. The analysis for the surface structure of the semi-cokes before and after the reforming reaction shows that the C2013;NH2, etc., functional groups on the surface of the semi-cokes participated in the reforming reaction, the coal rank and the BET are the main factors which influenced the catalyst performance, and the functional groups on the surface of the semi-cokes and the types and amounts of alkaline metals have a certain type of influence on the activity of the reforming reaction. [Copyright &y& Elsevier]

Abstract: The effect of doping traditional Co–Mo/Al2O3 catalysts with Ce and K on their catalytic activity for the water gas shift reaction in coke oven gas was investigated. Doped Co–Mo/Al2O3 catalysts were prepared by adding different amounts of Ce and K (CeO2, K2O, and CeO2–K2O ∼10 wt%) by a wetness impregnation method and characterized by BET specific surface area measurements and scanning electron microscopy (SEM). The characterization results reveal that CeO2 addition mainly produced an electronic effect and aided to disperse the active ingredient. At the same time, the synergistic effect between Ce and K contributed to the catalytic activity. Activity tests showed that Ce–K-promoted Co–Mo/Al2O3 catalysts exhibited greater activity and selectivity than Co–Mo–Ce/Al2O3 catalysts and Co–Mo–K/Al2O3 catalysts. The maximum promotion of the water gas shift reaction was observed when 3.0 wt% CeO2 and 6.0 wt% K2O were added. [Copyright &y& Elsevier]

Abstract: CO2 reforming of CH4 was studied over laboratory-prepared carbonaceous catalysts at atmospheric pressure (0.1MPa) and high pressure (3.6MPa). The catalysts were characterized by BET and FITR techniques. The catalytic activity and stability of catalysts were closely related to the reaction pressure. It was observed that the use of higher pressure substantially decreased CO2 and CH4 conversion and increased catalyst deactivation during CO2 reforming of CH4, compared to runs at 0.5MPa for carbonaceous catalysts. Deactivation was related to carbon formation. Some process adjustment methods, such as increasing the reaction temperature, prolonging reaction residence time, and increasing CO2 and CH4 molar ratio, which could improve catalysts activity and stability. Besides, the positive effect of surface oxygen containing groups (C–O) on catalyst activity had been demonstrated over carbonaceous catalysts. The basic function of the carbonaceous materials surface area also seemed to increase H-abstraction of methane and CO2 adsorption. [Copyright &y& Elsevier]

Abstract: Zearalenone (ZEA) and its derivative α-zearalenol (α-ZOL) are produced by fungi of the genus Fusarium and, after ingestion via contaminated cereals, may lead to animal fertility disturbances and other reproductive pathologies. The previous study demonstrated the toxic effects of ZEA and α-ZOL through disturbances in male fertility and other reproductive pathologies in mice. In this study, we further examined the direct biological effects of ZEA and α-ZOL on steroidogenesis production, primarily in Leydig cells of mice. Mature mouse Leydig cells were purified by Percoll gradient centrifugation and the cell purity was determined by 3β-hydroxysteroid dehydrogenase (3β-HSD) staining. To examine ZEA and α-ZOL-induced biological consequences, we measured testosterone secretion and transcription level of 3 key steroidogenic enzymes including 3β-HSD-1, P450scc and StAR, in ZEA and α-ZOL/human chorionicgonadotropin (hCG) co-treated cells. Our results showed that ZEA and α-ZOL (10−4 M, 10−6 M and 10−8 M) significantly suppressed hCG (10ng/ml)-induced testosterone secretion. The suppressive effect is correlated with a decrease in the level of transcription of 3β-HSD-1, P450scc, and StAR (P <0.05). [Copyright &y& Elsevier]

• The porosity distribution inside a porous AM60 sample is investigated via XRT. • The DIC strain mapping was used to verify the reliability of the FE result which contains 6813 pores with various characteristics. • The local stress/strain in the vicinity of large pores evolves progressively along with deformation. • The harmfulness of individual pores located in defect bands of HPDC AM60 alloy is firstly evaluated through finite element analysis. Casting pores are regarded as the main factor causing stress/strain concentrations, facilitating the initiation of microcracks and shortening the plasticity of a cast component. The influence of pore characteristics (i.e., size, morphology, and position) on local stress concentration in a High Pressure Die Cast (HPDC) AM60 sample is studied utilizing X-ray tomography (XRT) and image-based finite element (FE) techniques. Heterogeneous porosity distribution is identified in terms of volume fraction and projected area ratio per segment. Statistically results demonstrate that small pores (volume < 0.01 mm3) have higher number frequency and sphericity. In contrast, large pores (volume > 0.01 mm3) account for a very low number frequency (0.3%), and complex shape. The present study addresses the local stress/strain behavior in a cast-pore containing HPDC AM60 sample during tensile loading investigated using 3D image-based models which consider the actual size, morphology, and spatial distribution of pores based on XRT images and consider the actual material properties of the AM60 alloy. Simulation results show that the local stress/strain around a pore evolves progressively with deformation. The strain at a certain pore location may be amplified or reduced in the presence of other pores, depending on the specific location of the concerning pores. Also, the ratio between the projected area of a pore and its shortest distance to the free surface (PA/SD) could give a good indication of the max local stress concentration around the pore surface. The weakening of K t pl values of pores found in defect bands are principally due to the pore orientation concerning the load direction. These findings may be extended to provide additional insight into the damage mechanisms in material containing casting pores and to enhance understanding of the ductility variation in terms of local deformation fields around pores and their interactions. [ABSTRACT FROM AUTHOR]

For soft robots, fluid power is an essential propulsion technique. The pump, which is the "heart" of these systems, has significant issues with size, weight, and noise. It also needs to be kept separate from the robot body, which restricts the robot mobility and independence. Common actuation mechanisms for flexible pumps are examined in this paper, with an emphasis on portable flexible pumps for small and miniature soft robots. In addition, an overview of the literature on flexible pumps functionality and flexibility is given, which divides the study into three categories: partially flexible pumps, fully flexible pumps and pump-actuator integrated pumps. This evaluation focuses on the design, production, and performance of pumps. Finally, the primary area of research on flexible pump technology and potential applications are outlined. [ABSTRACT FROM AUTHOR]

Shales with inclined beddings are frequently encountered in formation reservoirs as burial depth increases. However, limited research has focused on the influence of wellbore orientation and stress magnitudes when hydraulically fracturing inclined shale reservoirs. To close this research gap, a series of hydraulic fracturing experiments were conducted to investigate the effects of different wellbore orientation angles (α = 0–90°) and axial stress magnitudes (σv = 0–20 MPa) on hydraulic fracture initiation and propagation in inclined bedding shales. After fracturing, a 3D laser scanner is employed to characterize the fracture surface roughness, and three independent parameters (SD, θs, Rs) are used to quantitatively evaluate the roughness of the fracture surfaces. The results show that increasing the wellbore orientation angles (α) results in a first decreasing and then increasing trend of the fracture initiation pressure (Pi), breakdown pressure (Pb) and roughness of fracture surfaces. The wellbore orientation angle (α) of 45° is beneficial to reducing the Pi, Pb and roughness of the fracture surface. However, relatively low critical fluid pressures will facilitate the reduction of surface roughness under the impact of wellbore orientation. Increasing axial stress in inclined bedding shale reduces the fracture initiation pressure (Pi) and breakdown pressure (Pb) while enhancing the roughness of the fracture surfaces. In field fracturing, adjusting the wellbore inclined to the bedding (45° is preferred) and in the burial depth with a stress difference greater than 10 MPa benefit the improvement of hydraulic fracturing performance. These findings offer an essential reference for designing hydraulic fracturing in shale reservoirs. [ABSTRACT FROM AUTHOR]

Carbon nanofibers/tubes were successfully formed by catalytic cracking methane using Al 2 O 3 /KOH as the catalyst precursors. The effects of pyrolysis temperature and the molar ratio of Al 2 O 3 to KOH on the growth of carbon nanofibers/tubes were investigated. The results showed that the precursors were transformed into potassium aluminate (K 2 O·Al 2 O 3) during the heating process. Pyrolysis temperature and molar ratio have great influence on the conversion rate of methane, the morphology and the graphitization degree of the products. The optimum temperature for the growth of carbon nanofibers/tubes was 900 °C and the diameter was 50–150 nm. Clusters of carbon nanofibers/tubes were also observed in the products. Finally, the formation mechanism of carbon nanomaterials was discussed based on the morphological changes of the products at different temperatures and the existing theories. At low temperature, methane was cracked under the action of catalyst to form metastable carbon nanosheets. After increasing the temperature, the product was transformed into more stable carbon nanofibers/tubes. However, excessive temperature would increase the size of the catalysts, thereby weakening the precipitation power of carbon nanofibers/tubes, and finally forming carbon nanospheres. Unlabelled Image • Carbon nanofibers/tubes (CNFs/CNTs) were successfully formed using Al 2 O 3 /KOH as the catalyst precursors. • The morphology of carbon nanomaterials sequentially transformed into carbon nanoflowers, CNFs/CNTs and carbon nanospheres. • The optimum temperature for the growth of CNFs/CNTs was 900 °C and the diameter was 50-150 nm. • The formation mechanism of carbon nanomaterials was discussed. [ABSTRACT FROM AUTHOR]

As an important manufacturing process for Mg-alloy components, high pressure die casting (HPDC) has attracted considerable attention. However, the application of magnesium alloy high pressure die castings is limited by variations in the mechanical properties, which can be ascribed to a heterogeneous distribution of microstructure. In this work, the through-thickness distribution of the microstructure features (i.e. grain size, β-phase and porosity) of HPDC AM60 alloy and their effects on the strain heterogeneity and the microhardness variation were carefully investigated. The results show that the HPDC AM60 alloy exhibited a gradient structured microstructure, i.e., two skin layers sandwiching a core layer. The skin was mainly comprised of fine grains (diameter ≤10 μm), whereas the core predominately consisted of externally solidified crystals (ESCs). Furthermore, the skin shows higher number and area fractions of β-Mg 17 Al 12 particles. Heterogeneous through-thickness distribution of microhardness was observed in the as-cast sample, and the skin showed higher the microhardness than the core. β-Phase was the primary factor accounting for heterogeneous distribution of microhardness. In the as-cast sample, strain heterogeneity was measured at strain of 3% using digital image correlation (DIC) method. The strain in the skin regions was homogeneous, whereas significant strain heterogeneity was presented in the core. After T4 treatment, remarkable strain heterogeneity was still observed, indicating that β-phase did not have profound effect on deformation heterogeneity. Strain localized at the interdendritic regions of ESCs and the vicinity of grain boundaries in fine-grained regions, where porosity occurred. This illustrates that porosity was the primary factor inducing strain localization. [ABSTRACT FROM AUTHOR]

In this paper, the changes in solid-phase carbon structure and the formation of carbon nanotubes in the process of K-catalyzed pyrolysis of bituminous coal were investigated. The results showed that the content of carbon nanotubes in K-catalyzed coal pyrolysis products increased with the extension of residence time. When the residence times were 0, 30 and 90 min, the yields of carbon nanotubes in the coal pyrolysis products were 1.98 wt%, 6.85 wt% and 10.16 wt%, respectively. It was found that the aromatic carbon C C, C H and ether carbon C-O-C structures in coal were the main carbon sources for the growth of carbon nanotubes. The probable growth mechanism of carbon nanotubes in the process of K-catalyzed coal pyrolysis was proposed to be as follows: aromatic C C and C H structures in coal convert K components such as K 2 CO 3 and K 2 O into metal K, and then metal K converts carbon atoms in the ether bond C-O-C structure into carbon atoms or clusters, which generate carbon nanotubes under the action of Fe catalyst particles in coal. This method provides a new strategy for the simultaneous high-value utilization of coal resources and macroscopic, low-cost preparation of carbon nanotubes. Unlabelled Image • Carbon nanotubes were directly synthesized from K-catalyzed coal or coke pyrolysis. • Type of carbon structure in coal required for carbon nanotubes growth was determined. • Formation mechanism of carbon nanotubes from K-catalyzed coal pyrolysis was proposed. [ABSTRACT FROM AUTHOR]

Porosity plays an important role in determining the ductility in magnesium alloy high pressure die castings. In this work, X-ray Tomography (XRT), fractographic analysis and Digital Image Correlation(DIC) have been implemented to understand the inter-relation between various pore characteristics, specifically porosity spatial distribution and morphology, and the ductility in thin-wall AM60 alloy high pressure die casting. The results show that a great amount of porosity was detected in the 20 studied samples. The pore size follows the three-parameter lognormal distribution. Among the detected porosity, small porosity (equivalent diameter ≤90 μm) is numerically dominant and the proportion in number reaches up to ~80%, which constitutes ~50% of the volume of porosity. In comparison, the large porosity (equivalent diameter >425 μm) accounts for a very low percent of the porosity population, namely ~1%, and only occupies ~5% of the volume of porosity. For through-thickness distribution of porosity, two defect bands were observed consisting of concentrated porosity. A great amount of pores randomly distributed pores in the skin and core, and some large pores (equivalent diameter >425 μm) are presented in the core. In addition, along tensile axis, heterogeneous porosity distribution is displayed in terms of local porosity and pore size. Tensile test coupled with DIC measurement has been conducted for the twenty samples with XRT data and the influences of various parameters of pore, including local porosity, size and position of pore, on the ductility have been analyzed. It can be seen that the local porosity in the fracture segment plays the primary role in determining the ductility, although the location and size of pore have effect on deformation heterogeneity and thereby affect the ductility. Therefore, the ductility can be considered as a function of the local porosity in the fracture segment. Moreover, though it's difficult to obtain the local porosity in the fracture segment prior to tensile test and the ductility can't be predicted based on it, there is a clear correlation between the elongation and the highest local porosity in the gauge, which can be got before tensile test, and thus ductility can be estimated accordingly. [ABSTRACT FROM AUTHOR]

To study the differences in material performance between HRB400E steel and conventional strength steel, this paper performed monotonic and cyclic loading tests on HRB400E and Q355B steels under a series of loading protocols. Additionally, the self-designed fixtures were used to achieve large strain rate loading. The ductility, monotonic behavior and hysteretic characteristics of HRB400E and Q355B steels were assessed, along with the energy dissipation capacity evaluated through the energy dissipation coefficients. The cyclic skeleton curves of both steels were fitted using the Ramberg-Osgood model, with further investigation into the influence of kinematic hardening parameters on hysteretic curves. The combined hardening parameters of the Voce-Chaboche model were calibrated based on the experimental results, and the hysteretic curves were simulated under different loading protocols via ANSYS. The analysis results reveal that the energy dissipation coefficients of HRB400E steel are larger than that of Q355B steel, yet smaller than those of Q460D, LYP100, LY100, LY160, and LY225 steels. Both HRB400E and Q355B steels demonstrate significantly improved material strength under cyclic loading. Excellent agreement between simulated and experimental curves is achieved when using four pairs of kinematic hardening parameters. Additionally, the hysteretic performance of HRB400E and Q355B steels under different cyclic loading protocols can be precisely simulated by employing calibrated combined hardening parameters. Through this paper, the cyclic behavior and constitutive relations of HRB400E steel are comprehensively understood, which provides a reliable theoretical basis for engineering design and structural analysis. Furthermore, this research provides a scientific basis for material applications of HRB400E steel. • HRB400E steel and conventional strength steel are compared in material performance. • Monotonic and cyclic loading tests are conducted. • Ductility, monotonic property, and hysteretic performance of HRB400E and Q355B steels are assessed. • Self-designed fixtures are utilized to achieve large strain rate loading. • The hysteretic property of the HRB400E steel can be accurately simulated. [ABSTRACT FROM AUTHOR]

Purpose: Osteoarthritis (OA) is the most common inflammatory disease associated with pain and cartilage destruction. Interleukin (IL)-1β is widely used to induce inflammatory response in OA models. This study aimed to explore the role of Danshensu (DSS) in IL-1β-induced inflammatory responses in OA. Methods: IL-1β was used to induce chondrocyte inflammation. Cell viability was evaluated by Cell Counting Kit-8 (CCK-8) assay. IL-6, COX-2, TNF-α, and iNOS mRNA levels were detected by qRT-PCR. MMP3, MMP13, ADAMTS4, ADAMTS5, Aggrecan, Collagen, p-IκBα, and p-p65 protein levels were detected by Western blot. An OA mouse model was established by surgical destabilization of the medial meniscus (DMM), and the Osteoarthritis Research Society International (OARSI) score was evaluated by H&E staining. Results: DSS did not affect the levels of inflammatory indicators including IL-6, COX-2, TNF-α, iNOS, PEG2, and NO but suppressed COX-2 and iNOS protein expression in IL-1β treated chondrocytes. In addition, DSS downregulated IL-1β-enhanced expression of MMP3, MMP13, ADAMTS4, and ADAMTS5 and upregulated aggrecan and collagen expression. Moreover, DSS significantly inhibited IL-1β-induced phosphorylation of p-IκBα and p-p65 in a dose-dependent manner in chondrocytes, suggesting it plays a role in the NF-κB signaling pathway. Furthermore, DSS significantly reduced DMM-induced cartilage OARSI score in mice, further demonstrating its protective role in OA progression in vivo. Conclusions: Our study revealed the protective role of DSS in OA, suggesting that DSS might act as a potential treatment for OA. [ABSTRACT FROM AUTHOR]

Failures of the topcoat in pavement structures often occur due to mixed mode I/III traction; however, incorporating basalt fibers (BFs) into cement mixtures can effectively enhance mortar toughness and improve service conditions. To gain a deeper insight into the fracture behavior of BF-reinforced cement mixture, the Edge Notch Disc Bend (ENDB) testing with acoustic emission (AE) technique was first conducted on BF reinforced mortar specimens considering three different dosages of BFs (0%, 0.3% and 0.8% by weight). Four fracture parameters, including effective fracture toughness (K e), effective work of fracture (W p), effective critical fracture toughness (K eff) and effective critical work of fracture (W p-eff), were employed to assess the fracture performance of BF-reinforced mortars. The results show that the K e for mode III is significantly lower than that for mode I, while W p is critical for mode III. Interestingly, the increase in K e , K eff , W p and W p-eff is closely associated with the micro behavior involved in reducing the effective critical distance. Then, the digital reconstruction of fracture surfaces was performed, revealing that the fractal and roughness characteristics of the fracture surface subjected to mode І І І loading are more pronounced than those under mode I loading. These results can be further enhanced by the fiber crack-bridging effect. Moreover, it is validated that the out-of-plane shear failure induced by tensile stress occurs specifically under pure mode І І І loading state (K І c > K І І І c and 90% shear-type waveforms), which illustrates the feasibility of applying pure mode III load under ENDB testing. By analyzing variations in dominant frequency and b value, we demonstrate that mortars with higher BFs content exhibit a greater prevalence of shear-type microfractures characterized by smaller rupture scales and weaker heterogeneity under mode І І І loading conditions. These findings can offer a novel perspective on elucidating the crack-bridging effect of fibers during the rupture of fiber-reinforced mixtures. [Display omitted] • The enhancement in fracture performance of mortar is associated with micro behavior involved in reducing the effective critical distance. • The morphological characteristics are more pronounced for BF reinforced mortar towards mode І І І loading. • The capability of the ENDB configuration to induce pure mode І І І failures was confirmed through AE signal analysis. [ABSTRACT FROM AUTHOR]

To gain deeper insight into the effects of unloading normal stress on shear mechanical behaviour, laboratory tests are carried out on the red-sandstone specimens containing a parallel fissure pair under the constant shear stress and the unloading normal stress. The results reveal that the trace of the entire rupture surface is mainly controlled by the rock bridge, and the impacts of the rupture surfaces of the unloading tests are narrower than those of the direct shear tests. Tensile failure, tension–shear failure, shear failure, and two-stage failure are observed, the failure rules of rock bridges are further summarized according to the ranges of the length and inclination of the rock bridge. The shear strength of the normal unloading test has a slight increase compared with that of the direct shear test. With an increase in the initial normal/shear stress, the shear strength of rock specimens increase; under the low to medium initial stress conditions, the shear strength increment has a linear growth tendency, but under the medium to high initial stress conditions, the growth trend slows down. The ratio of shear deformation on rupture surface increases with the increase of the initial shear stress but decreases with the increase of the initial normal stress. The ratio of shear deformation on rupture plane increases with the increase of the initial shear stress, and decreases with the increase of the initial normal stress, There is a little difference in the deformation ratio (shear damage deformation divided by tensile damage deformation, ΔDrs/ΔDrn) between the observed tensile failure and tension–shear failure. The dominate damage deformation under different geometric conditions is closely related to the failure patterns. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing is a powerful technology, especially in stimulating fluid production from reservoirs. However, the problem of the intersection between hydraulic fractures and natural fractures is inevitable in engineering practice due to naturally fractured formations. This paper presents a new criterion for a toughness-dominated hydraulic fracture crossing a natural frictional interface through coupling the fluid flow and elastic deformation of the hydraulic fracture prior to intersecting with the natural frictional interface. The critical condition for the hydraulic fracture crossing the natural frictional interface is that the total superimposed stress does not satisfy the failure condition of the Mohr–Coulomb criterion. Simultaneously, the new criterion considers nonorthogonal intersection angles and six independent parameters relating to fluid flow (hydraulic fracture half-length, approaching distance and injection rate), rock mechanic properties (rock fracture toughness and Young's modulus) and in situ stress. The prediction outcomes show good agreement with laboratory experiments as well as sufficient advantages compared with the analytical criteria of Blanton, extended Renshaw-Pollard and Llanos. Parameter sensitivity analysis is conducted using the control variable method. The parametric analysis results reveal that the influence sphere of different parameters is limited to a certain extent by the variations in the intersection angle except for Young's modulus and the injection rate, which show slight effects on the intersection behaviors. [ABSTRACT FROM AUTHOR]

Abstract The influence of crystallographic texture on deformation mechanism and work-hardening behavior of the Mg-2Zn-0.1Ca alloy sheet was investigated via quasi-in-situ slip traces analysis. The results show that the sheet displayed a weakened transverse direction (TD) spread texture. The rolling direction (RD) sample exhibited the highest yield strength (104.3 MPa), while the TD samples exhibit the lowest (68.6 MPa), implying a high dependency of yield strength on texture. A deformation mechanism transition were observed in the RD, 45° and TD samples, i.e. basal slip (ε = 0.5%) → basal slip + non-basal slip (ε = 1.5%) → basal slip + non-basal slip + twinning (ε = 7.5%), and non-basal slip was activated to accommodate the imposed deformation due to the increment in an applied shear stress for basal slip with deformation processing. Additionally, the anisotropy of deformation modes is pronounced. At ε = 0.5%, basal slip primarily operated in the grains with high Schmid Factor (SF ≥ 0.35) in TD sample, while in the RD sample, the SFs for basal slip exhibited a wider distribution and prismatic slip also operated. As strain reached to 7.5%, twinning played more important role in the TD sample than the 45° and RD samples. Moreover, the texture has a substantial influence on work hardening behavior. At ε = 1.5%, work hardening rate was governed by SF distribution for basal slip. The sample with more grains exhibiting low SF for basal slip shows higher WH rate. However, twinning plays an important role in effecting work hardening rate at ε = 7.5%, and consequently the TD sample with the greatest area fraction of twin (f twin) has the highest work hardening rate. Highlights • A new insight of deformation mode transition was provided. • The dependency of deformation mode on the TD-spread texture was discussed. • A quantitatively understanding about anisotropy of the yield strength was revealed. • An alternative interpretation of the effect of texture on WH behavior was presented. [ABSTRACT FROM AUTHOR]

The pressure-pulse decay is a preferred technique for determining permeability of unconventional gas reservoir rocks. The pressure-pulse decay often shows quite different characteristics during the early time and the later time. Most approaches for estimating the permeability proposed in the literature are required to use the later-time pressure-pulse decay measurements. However, the later-time data are often selected subjectively, lacking a universal criterion. In this paper, a method of differentiating the early-time and late-time behavior for pressure-pulse decay test is proposed. The analytical results show that the critical time (dimensionless time) of early-/late-time decay characteristics mainly depends on the volume ratios, and it increases first and then decreases with the volume ratios. The critical time for cases with same chamber sizes is much less than that for cases with unequal chamber sizes. Applicability of the proposed methods is examined using a numerical simulator, TOUGH+REALGASBRINE. The numerical results show that the pressure gradient along the sample varies nonlinearly at the early time and becomes a constant at the late time. Then, the proposed method is applied to real data for permeability estimation. It is found that the early-time behavior is negligible as the volume ratio takes on small values. As the volume ratios increase, the deviation becomes significant and considerable permeability errors will be produced if these early-time data are used. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a type of liver cancer that is associated with high mortality rates. This study aims to investigate the role of ZNF655, a member of the zinc finger protein family, in the development of HCC. Immunohistochemical staining analysis was conducted to evaluate the expression of ZNF655 in HCC patient samples. Lentivirus‐mediated ZNF655 knockdown was established in HCC cell lines (BEL‐7402 and HCCLM3). The effects of ZNF655 on different aspects of HCC cell behavior such as proliferation, apoptosis, cycle, migration and tumor formation were examined. Downstream targets of ZNF655 in HCC were identified and verified through loss/gain‐of‐function experiments. Clinically, ZNF655 expression was elevated in HCC and increased with the severity of the disease. Functionally, inhibition of ZNF655 expression reduced the progression of HCC cells by decreasing proliferation, causing apoptosis, arresting cell cycle retention in G2, suppressing migration, and attenuating tumor formation in mice. Mechanistically, the proteasome subunit beta type‐8 (PSMB8) was found to be co‐expressed with ZNF655 in HCC, and PSMB8 knockdown weakened the promotion of ZNF655 overexpression on HCC. In summary, these findings suggest that ZNF655 promotes the progression of HCC through PSMB8, and inhibition of its expression may be a promising therapeutic target for HCC. [ABSTRACT FROM AUTHOR]

As the essential component of shale, clay minerals have a vital influence on the pore structure and the gas content of reservoirs. To investigate the compositional characteristics of coal-measure shale and its effects on pore structure, a total of thirteen Taiyuan formation shale samples were collected from the Qinshui Basin and were analyzed using a combination of X-ray diffraction analysis, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy (FE-SEM), polarized optical microscopy, and field emission scanning electron microscopy. The results show that the principal minerals of the samples are quartz, kaolinite, and illite. Most of the kaolinite was an original terrigenous detrital material with low crystallinity and a low degree of ordering, whereas the illite was mainly composed of 1Md resulting from diagenesis. Clay minerals developed slits, irregularly-shaped or multisized pores during diagenesis, which can be classed into interlayered pores, intergranular pores, and microfractures. Eight micro-morphological forms of clay minerals were summarized based on FE-SEM observations, such as compacted, parallel, bent, tilted, mutually supporting structures, etc., which are mainly formed by the mechanical compaction of clay minerals with different sizes, shapes, and contact relationships. The diversity and complexity of the micro-morphological forms of clay minerals contribute to the strong heterogeneity, low porosity and high permeability anisotropy of shale. [ABSTRACT FROM AUTHOR]

In this work, a thermal-mechanical coupling smooth particle hydrodynamics-phase field method (TM-SPH-PFM) model was proposed to study the thermal fracturing problem in rocks. Here, we derived the discrete forms of the mass conservation equation, momentum conservation equation, heat conduction equation, and phase field damage evolution equation using kernel function approximation and particle approximation methods. According to the Benzeggagh-Kenane criterion, new crack driving forces that consider the nonlinear interactions between two fundamental crack patterns are established. The discontinuity at the crack site after rock cracking is determined by the interaction parameters. We proposed a multirate explicit time integration method to address the issue of different time scales between temperature and mechanical fields. The correctness and convergence of the numerical model have been verified through three benchmark examples: the steady-state heat transfer problem, the transient heat transfer problem and two-dimensional double-notched specimen cracking under temperature. Subsequently, the effect of the coefficient of thermal expansion and the degree of inhomogeneity of the rock on the pattern of thermal fracture is modelled, and the heating fracture of Lac du Bonnet granite with a central circular hole is simulated. The current numerical model can serve as an effective tool for simulating rock thermmal-elastic fracture problems. [ABSTRACT FROM AUTHOR]

Aiming at the general problem that both for the production of foundry coke made by anthracite pulverized coal and furnace coke made by tamped coke in the coke oven, namely the shrinkage problem for large-size briquette and tamped coke in the pyrolysis process, a mass and volume integrated measuring device was used to study the shrinkage process of large-sized briquettes (volume equals 10 3 cm 3 ) under constant temperature (450 °C, 550 °C, 650 °C and 850 °C). The briquette shrinkage kinetic model was also established according to the regulation of mass loss and volume shrinkage, where the volume shrink calculation method of tamped coal cakes (13,280 mm × 500 mm × 4300 mm) was also obtained. Three conclusions were drawn in this study: 1. In the process of the carbonization, the dehydration and degassing reaction before 450 °C as well as polycondensation reaction at 650 °C were the main reason causing the briquette shrinkage, the decomposition reaction at 550 °C came second, while the hydrogen evolution reaction after 850 °C has the least effect on briquette volume shrinkage. There were three main reasons causing the shrinkage of large-size briquette: the decrease of coal volume caused by the volatilization of moisture and volatiles, the decrease of coal volume caused by the pyrolysis reaction and the density increase of briquette caused by the decrease of coal volume. 2. The briquette shrinkage kinetic model was represented as follows: d V t /d t = V 0 [(1 − x )d β /d t − A 0 e − E / RT (1 − x ) n β ]; There was a positive correlation between the volume changing parameter β and the density of briquette, and the volume changing parameter increased with the reaction; the shrinkage reaction was divided into three stages; with the reaction went on, the reaction order and reaction rate constant decreased, the pre-exponential factor increased and the activation energy decreased firstly and increased then. 3. The shrinkage of the tamped coal cakes from the large-scale chamber was counted in the calculated unit whose thickness was 100 mm. The shrinkage velocity of the tamped coal cakes in carbonization chamber was obtained by weighted calculating the shrinkage parameters of each volume unit at different temperatures. The shrink regulations of the tamped coal cakes in the carbonization chambers, which were in agreement with industrial production, were approximately the same as those of the large-sized briquettes. However, the shrinkage rate curve of the tamped coal cake in the carbonization chamber was gentler than that of the large-sized briquette, as a result of the large temperature gradient of different coal in carbonization chamber. [ABSTRACT FROM AUTHOR]

The effect of H 2 –CO ratio, reduction temperature and time on the reduction degree, mineral phase, and morphology of the reduced production was investigated in this study by reducing hematite with coke oven gas (COG) as the reducing agent to alleviate the pressure from the increasing demand of iron ore. The kinetics analysis, reduction mechanism, and deposited carbon behavior were proposed. The results revealed that the reduction degree reached the maximum value of 94.69% at the temperature of 900 °C for 10 min in a simulated COG atmosphere. At 800 °C, the pores and cracks on the surface of the particle became more and wider as the reaction time increased. When the reaction time reached 30 min, massive Fe 3 C was attached to the surface, and the newly formed spherical metallic irons were bonded to each other and randomly distributed on the surface of the product particles. Besides, the deposited carbon mainly existed in two forms of a rough porous structure and cluster structure when the temperature increased to 900 °C. The hematite reduction process was mixed-controlled by one-dimensional diffusion reaction and three-dimensional interfacial reaction, and the activation energy decreased to 50.79 kJ/mol. • The reduction of hematite in COG atmosphere was conducted in a rotary bed reactor. • The reduction mechanism and carbon deposition behaviors were studied. • The reduction degree reached the maximum value of 94.69% in simulated COG atmosphere. • The deposited carbon was mainly existed in rough porous and cluster structure. • The hematite reduction was mixed controlled by diffusion and interfacial reaction. [ABSTRACT FROM AUTHOR]

• A rapid method for fitting RPT model is proposed which allows direct modeling of the RPT by fitting formula. • Numerical validation indicates that the fitted RPT method achieves high accuracy for typical plate element dispersed particle fuel problems. • Three important geometric parameters are identified in relation to the RPT model by a quantitative method. The reactivity-equivalent physical transformation method transforms the double heterogeneity problem into the traditional single heterogeneity problem, which has the advantages of simplicity and efficiency. However, the current reactivity-equivalent physical transformation methods mainly focus on rod-type fuel elements rather than plate-type elements. Therefore, an optimization research is conducted for the reactivity-equivalent physical transformation method applicable to fuel plates containing dispersed particles in this paper. First, this method is obtained by identifying three important geometrical parameters and fitting equivalent side lengths quickly. Next, the single plate-type fuel is build by OpenMC to verify the physical characteristics which about steady-state verification, depletion verification, temperature coefficient, key nuclide density, fission rate verification and neutron spectrum verification. Finally, the numerical validation indicates that the fitted reactivity-equivalent physical transformation method achieves high accuracy for typical plate element dispersed particle fuel problems. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new idea for oil production by co-pyrolysis of oil shale and cherry pit was given. • Adding 30% oil shale into cherry pit rose up the oil yield by14.63% during pyrolysis. • More oxygen migrated into oxygen-containing gases rather than co-oil and char. • More H · free radicals preferring to attack H α and H ar led to a rising co-oil quality. • Synergistic effect occurred during co-pyrolysis due to the hydrogen migration. The pyrolysis oil of oil shale is characterized as being of better quality and having a lower yield, whereas the bio-oil from cherry pit has a higher yield but a higher oxygen content, which limits their efficient and clean application. Thus, the pyrolysates characteristics of oil shale and cherry pit have been investigated using a fixed bed reactor to fully utilize their inherent properties in this paper. In addition, the interaction mechanism during co-pyrolysis is explored by analyzing the hydrogen migration pathways. The results reveal that a remarkable synergistic effect on the oil and gas occurs during co-pyrolysis, and the co-oil yield of OS 30 CP 70 improves by 14.63 % compared with the weighted value. During co-pyrolysis, the concentrations of hydrogen- and oxygen-containing gases are higher than expected, and the hydrogen and oxygen contents of char are lower than expected, which is related to that more hydrogen and oxygen of oil shale and cherry pit migrate into gas instead of char. Additionally, more hydrogen and less oxygen migrate into the co-oil during pyrolysis, causing an increase in aliphatics and a reduction in aromatics and oxygenated compounds, and enhancing the quality of the co-oil. 1H NMR shows that the H · free radical is most likely to attack the H α and H ar sites of cracking fragments rather than H β and H γ sites, resulting in the co-oil containing more short-chain aliphatics and aromatics with fewer rings. Besides, the alkali and alkaline earth metals in cherry pit improve the cracking of hydroxyl and carboxyl groups and inhabit the migration of oxygen into co-oil, leading to a decrease in H o content. The energy efficiency of co-pyrolysis is higher than that of individual pyrolysis, which all exceed 90 %. [ABSTRACT FROM AUTHOR]

Coking sulfur paste (CSP) is a hard-to-handle industrial solid waste. With the high sulfur content, CSP can be used to prepare asphalt modifier. This paper investigated the release characteristics of polycyclic aromatic hydrocarbons (PAHs) in CSP during heating. While heating from 42°C to 480°C, CSP demonstrated two weight loss stages in which certain organic compounds were evaporated from CSP. The volatiles were primarily benzene and four kinds of PAHs, including naphthalene, indene, fluorene, and phenanthrene. The total absolute release amount of volatiles increased with increase in temperature. Furthermore, to remove PAHs, CSP was sulfonated with 98% H2SO4. The optimal sulfonation conditions in the molten state of CSP were as follows: ratio of H2SO4 volume to CSP mass 60 μL·g−1 and reaction time 60 min. At 160°C, the total absolute release amount of benzene and four kinds of PAHs decreased from 14.688 × 103 to 0.18 μg·g−1. Therefore, the removal of PAHs from CSP using a sulfonation agent is very effective, ensuring that CSP can be used in road engineering without pollution. [ABSTRACT FROM AUTHOR]

Background: The genomic alterations of intrahepatic cholangiocarcinoma (ICC) in the Chinese population have not been fully revealed. Molecular profiling may provide a reference for clinical management, especially targeted therapy.Methods: A retrospective study was conducted in 122 ICC patients. All patients' samples underwent next-generation sequencing (NGS), which analyzed 417 genes. The genetic characteristics, clinical management and therapeutic responses were analyzed.Results: The most commonly mutated genes were TP53 (34%), KRAS (25%) and ARID1A (17%). Targeted agents were used referring to molecular profiling, in combination with chemotherapy. Twenty-two patients with wild-type KRAS/NRAS/BRAF were treated with cetuximab. The disease control and response rates were 78% and 47%, respectively, which were higher than those achieved with chemotherapy alone (72% and 11%, P = 0.16). Fifty-four patients underwent anti-VEGF treatment with bevacizumab. The disease control and response rates were 85% and 60%, respectively. Better therapeutic efficiency (P = 0.001) and longer progression-free survival (PFS) were observed in the bevacizumab-treated group compared to chemotherapy alone group (15.4 and 6.7 months, respectively; P = 0.04). The PFS of ten patients who underwent hepatectomy after combined treatment with chemotherapy and bevacizumab was longer than that of 139 patients who underwent surgical treatment (28.9 vs 18.0 months, P = 0.03). Two patients (1.6%) had signatures of microsatellite instability (MSI-H), and both benefited from immunotherapy.Conclusions: This study provides an overview of genetic alterations in Chinese ICC patients and indicates the potential clinical implications for NGS-based personalized therapies. [ABSTRACT FROM AUTHOR]