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This paper addresses how residents can safely access shelters from their buildings. Firstly, we investigated Xiaying Village, a typical community with severe buildings damage at the epicentre of the Ms5.0 magnitude earthquake in Tonghai that occurred on August 13, 2018, and found that the injured residents when escaping resulted from the damage to masonry buildings. Secondly, a probabilistic approach combining response spectrum and allowable maximum acceleration is proposed to estimate the damage risk of masonry buildings with inadequate seismic performance in old communities. Thirdly, three models are proposed to assess the risk of the escape path, which include all scenarios of the escape of residents to shelters. Finally, an accessibility analysis of the paths that residents may choose to escape to the shelter is presented. The results of the community escape case study in the Tonghai earthquake show that the probabilistic approach to estimating the escape risk is feasible, and the number of damaged buildings in the escape path dictates the accessibility of residents to the shelter. The proposed method is important for guiding old community residents to escape when a strong earthquake strikes, and it is an effective way to improve community disaster resilience. [ABSTRACT FROM AUTHOR]

The launch of the Geostationary Ocean Color Imager (GOCI) satellite has made it possible to observe suspended sediment concentration (SSC) in the Bohai Sea (BHS) over a long time and a large area. We utilized remote sensing data from GOCI from 2011 to 2021 to study the spatiotemporal variation characteristics of SSC in the BHS and identified the contribution of each oceanic element to the changes in SSC. Our findings indicate that SSC is high in winter and low in summer, and related to the southeastward winds in winter (>7 m/s) and northwestward winds in summer (<4 m/s), with a correlation coefficient of 0.634. The average annual increase in SSC is 0.07 g/m3 (an increase of 1.2% per year). In terms of spatial distribution, SSC is highest in Bohai Bay and Laizhou Bay, followed by the Liaodong Bay, and is greater than that in the Central Bohai Sea, which is related to multiple river estuaries in the three bays. Additionally, the Bohai and Liaodong Bay in the BHS are covered by sea ice during winter, which affects the response of waves and currents to wind and changes the ocean current field, thereby affecting the resuspension and transport of sediment. Our EOF analysis revealed that wind-induced changes are the dominant factors in the variations of SSC, while changes in river runoff, sediment discharge, and sea ice cover are also important factors influencing SSC changes. • The annual increasing trend of the suspended sediment concentration (SSC) in the Bohai Sea has been analyzed using remote sensing data of GOCI satellite. • The periodic changes in wind speed dominate the periodic changes in SSC in the Bohai Sea. • The SSC in Liaodong Bay is lower than that in Bohai Bay and Laizhou Bay due to different ice coverage and sediment grain size. • Wind speed, river runoff, and sediment discharge contribute 71.8% to the SSC in the Bohai Sea through EOF analysis. [ABSTRACT FROM AUTHOR]

Detecting suspicious behavior from high definition (HD) videos is always a complex and time-consuming process. To solve that problem, a fast suspicious behavior recognition method is proposed based on motion vectors. In this paper, the data format and decoding features of HD videos are analyzed. Then, the characteristics of suspicious activities and the ways of obtaining motion vectors directly from the video stream are concluded. Besides, the motion vectors are normalized by taking the reference frames into account. The feature vectors that display the inter-frame and intra-frame information of the region of interest are extracted. Gaussian radial basis function is employed as the kernel function of the support vector machines (SVM). It also realizes the detection and classification of suspicious behavior in HD videos. Finally, an extensive set of experiments are performed and this method is compared with some of the most recent approaches in the field using publicly available datasets as well as a new annotated human action dataset including actions performed in complex scenarios. [ABSTRACT FROM AUTHOR]

The processes of motion target detection and tracking in most of traditional activity recognition methods are usually complicated and the application of these methods is limited. In this paper, we propose a fast violent activity recognition method based on motion vectors. First, we extract the motion vectors from compressed video data directly. Then, we analyze the features of the motion vectors in each frame and between frames, and get Region Motion Vectors descriptor (RMV). Finally, we use the Support Vector Machine (SVM) which takes the radial basis as the kernel function to classify the RMV and determine whether the violent activity exists in the video or not. Experimental results on several datasets have shown that the proposed method can detect 96.1% of the violent activities in videos (false probability is about 5.1%), and the calculation speed is very fast, which means the new method can be used in embedded systems. [ABSTRACT FROM AUTHOR]

Finger-vein verification is an emerging biometrics technology. Its first task is extracting finger-vein patterns. Although existing algorithms can extract most finger-vein patterns robustly, some branch of these patterns always breaks, which leads to adverse effects for features extraction and matching. In this paper, a Direction-Variance-Boundary Constraint Search (DVBCS) model is presented to restore the broken finger-vein patterns. At the beginning, endpoints of broken finger-vein branches are located. Then, a direction constraint for searching candidate point set is demonstrated. Following the second stage, an optimal target point is selected from the candidate point set according to a minimum within-cluster variance criterion. Eventually, the boundary constraint and variance constraint are introduced as the termination conditions. Experimental results illustrate that, while maintaining low segmentation error, the proposed method can restore above 10% lost target points. Moreover, the equal error rate of finger-vein recognition is reduced from 0.57% to 0.29% when using the proposed method to restore finger-vein patterns. [ABSTRACT FROM AUTHOR]

Finger-vein recognition is an increasingly promising biometric identification technology in terms of its high identification accuracy and prominent security performance. The main challenge faced by finger-vein recognition is the low recognition performance caused by segmentation error and local difference. To tackle this challenge, a finger-vein recognition method with modified binary tree (MBT) model is proposed in this paper. MBT model is used to describe the relationship and spatial structure of vein branches quantitatively. Based on the MBT model, four stages including rough selection, model correction, segment matching, and comprehensive judgment are presented to achieve a robust matching for finger-vein. Experiments demonstrate that the proposed method can boost the performance of finger-vein recognition that is degraded by segmentation error and local difference. While maintaining low complexity, the proposed method achieves 0.12 % equal error rate in the introduced dataset with 8,100 finger-vein images from 150 participants, which outperforms the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

An improved Harris corner detection algorithm is proposed based on Barron operator, since Harris corner detection algorithm has a poor accuracy in positioning complex corner detection and may miss certain real corners. Firstly, the image gradient is calculated by using Barron operator to reduce the calculation errors from Prewitt operator or Sobel operator. Secondly, the centre B-spline function is used to smooth image, filter noise, and retain the corners information better. Thirdly, a non-maximal inhibition and corners sieving method is used to determine whether the detected corners are real corners or not. A square window is centered at the pixel and eliminate the corner if the value of the corner response function is non-maximal in the window. And then divide the test image into several blocks so as to process each block independently, and use a cyclic iterative method to determine the threshold value to make sure that the real corners are accurately selected. Finally, experiments indicate the algorithm has relatively great noise proof ability and is able to extract complex corners effectively. [ABSTRACT FROM AUTHOR]

Abstract: One-dimensional α-MnO2 nanorods were fabricated by using low-temperature water-bathing chemical precipitation method at 80 °C. The crystalline structures, morphological evolution process and microwave absorption properties were systematically investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and measurement of electromagnetic parameters. The results show that the morphological structures and electromagnetic properties have close relationship with the reaction time. With the prolonging of the treatment time, the as-synthesized products turn from microspheres constituted of tiny dendrites to nanorods with diameters of 20–30 nm and lengths up to 1–2 μm. The electromagnetic characterization shows that the dielectric constants and magnetic permeability values show decreasing trends with the increasing frequency, however, the dielectric and magnetic loss tangents all increase with frequency. The electromagnetic absorption properties of the products have close relationship with the morphologies and thicknesses of the samples. With a thickness of 3 mm, an absorbing peak value of −25 dB was achieved for the sample treated for 24 h. The microwave absorption properties of MnO2 can be attributed mainly to interfacial polarization, space charge polarization and relaxation phenomena. [Copyright &y& Elsevier]

In this paper, an algorithm for smoke region of focus (ROF) detection based on surveillance video is proposed in order to solve the problem of limited application in scenes range and imaging environment of the traditional smoke detection algorithm. The frog vision perception model is used in this algorithm. First the suspect regions are detected, and then the static and the dynamic features of the regions are chosen for the smoke ROF detection. Experimental results show that the algorithm is efficient and significant for improving the operational rate of the detection. [ABSTRACT FROM AUTHOR]

In numerical simulation of quenching process, the boundary conditions of temperature field and stress field are very important, in which the boundary conditions of temperature field are very complicated. In order to simulate the thermal strains, thermal stresses, residual stresses and microstructure of the steel during gas quenching by means of the numerical method, it is necessary to obtain an accurate boundary condition of temperature field. The surface heat-transfer coefficient is a key parameter. The explicit finite difference method, non-linear estimate method and the experimental relation between temperature and time during quenching have been used to solve the inverse problem of heat conduction. The relationships between surface temperature and surface heat-transfer coefficient of cylinder have been given. The non-linear surface heat-transfer coefficients include the coupled effects between phase transformation and temperature. In calculation, physical properties were treated as the function of temperature and volume fraction of constituent. The results obtained have been shown that this technique can determine effectual the surface heat-transfer coefficients during gas quenching. [Copyright &y& Elsevier]

Motion object detection (MOD) with freely moving cameras is a challenging task in computer vision. To extract moving objects, most studies have focused on the difference in motion features between foreground and background, which works well for dynamic scenes with relatively regular movements and variations. However, abrupt illumination changes and occlusions often occur in real-world scenes, and the camera may also pan, tilt, rotate, and jitter, etc., resulting in local irregular variations and global discontinuities in motion features. Such complex and changing scenes bring great difficulty in detecting moving objects. To solve this problem, this paper proposes a new MOD method that effectively leverages local and global visual information for foreground/background segmentation. Specifically, on the global side, to support a wider range of camera motion, the relative inter-frame transformations are optimized to absolute transformations referenced to intermediate frames in a global form after enriching the inter-frame matching pairs. The global transformation is fine-tuned using the spatial transformer network (STN). On the local side, to address the problem of dynamic background scenes, foreground object detection is optimized by utilizing the pixel differences between the current frame and the local background model, as well as the consistency of local spatial variations. Then, the spatial information is combined using optical flow segmentation methods, enhancing the precision of the object information. The experimental results show that our method achieves a detection accuracy improvement of over 1.5% compared with the state-of-the-art methods on the datasets of CDNET2014, FBMS-59, and CBD. It demonstrates significant effectiveness in challenging scenarios such as shadows, abrupt changes in illumination, camera jitter, occlusion, and moving backgrounds. [ABSTRACT FROM AUTHOR]

The µW‐level power density of flexible piezoelectric energy harvesters (FPEHs) restricts their potential in applications related to high‐power multifunctional wearable devices. To overcome this challenge, a hierarchical design strategy is proposed by forming porous piezoceramics with an optimum microstructure into an ordered macroscopic array structure to enable the construction of high performance FPEHs. The porous piezoceramic elements allows optimization of the sensing and harvesting Figure of merit, and the array structure causes a high level of effective strain under a mechanical load. The introduction of a network of polymer channels between the piezoceramic array also provides increased device flexibility, thereby allowing the device to attach and conform to the curved contours of the human body. The unique hierarchical piezoceramic array architecture exhibits superior flexibility, a high open circuit voltage (618 V), high short circuit current (188 µA), and ultrahigh power density (19.1 mW cm−2). This energy density value surpasses previously reported high‐performance FPEHs. The ultrahigh power flexible harvesting can charge a 0.1 F supercapacitor at 2.5 Hz to power high‐power electronic devices. Finally, the FPEH is employed in two novel applications related to fracture healing monitoring and self‐powered wireless position tracking in extreme environments. [ABSTRACT FROM AUTHOR]

Aiming at the crowd in high-definition video motion state of sudden changes in rapid detection of abnormal crowd behavior problem, this paper proposes a kind of abnormal behavior crowd detection method based on motion vector. This algorithm is established upon the Social Force Model, first, extracts the motion vector in the code stream of the high-definition compressed videos, computes the interaction force in the social force model and rapidly draws the characteristics of the moving crowd; then according to the algorithm, we perform the bag of words approach and histogram statistics on the intensity and angle of the interaction force flow; finally we analyze two histograms to distinguish the moving state of the crowd and fulfill the detection of the abnormal crowd movement. The simulation experiment shows the method compared with the traditional social force model, in the 1024 × 768HD video frame processing speed on the average increase of 30% in average, the discrimination of abnormal frame advance 35 frames, the recall to an average increase of 22%. [ABSTRACT FROM AUTHOR]

In this study, uniaxial compressive tests combined with the digital image correlation (DIC) method are used to investigate the mechanical properties, fracture process, and failure pattern of sandstone containing a circular inclusion. A DIC‐based methodology is proposed to quantitatively explain the crack initiation and propagation mechanism. The identification criterion of crack type is presented based on the nature of cracks and the development trends of relative displacement. Three crack types, including tensile cracks, tensile–shear cracks, and shear cracks, with different cracking mechanisms are identified. The inhibitory effect of the inclusions on crack initiation and propagation is revealed. The inclusion–matrix debonding mechanism is further investigated, and it is found that the inclusion interface consists of tensile concentration zones on the left/right sides and compressive concentration zones on the top/bottom sides. The tensile concentration zone is the main reason for debonding of the inclusions from the sandstone matrix. Highlights: The effect of an inclusion on opening‐containing sandstones is studied.A DIC‐based method to directly identify rock cracking properties is proposed.The crack types of the specimens under different filling conditions are identified.The inclusion–matrix debonding mechanism is quantitatively investigated. [ABSTRACT FROM AUTHOR]

Destress blasting is regarded as an active mitigation measure for preventing rockbursts in deep underground works, whose mechanism and effectiveness, however, have still been in debate. A self-developed combined finite-discrete element method software is implemented in this study to first model the rock fracture process induced by a single-hole destress blasting based on a practical blast in a deep gold mine with high in-situ stresses. The effects of accelerometer holes and bedding planes are discussed. Then, a two-round tunnel face excavation in deep underground with high in-situ stresses is modelled, which reproduces the occurrence of the excavation-induced rockbursts. Finally, destress blast-holes are introduced into the same model prior to the two-round tunnel face excavation to investigate the effect of the destress blasting on the excavation-induced rockbursts. It is found that the fractures induced by the destress blasting shift the high abutment pressure induced by the excavation away from the tunnel face and then protect the tunnel wall from fracturing. The numerical modellings reveal that the success of the destress blasting in controlling excavation-induced rockbursts depends on not only the site condition but also the design of the destress blasting such as the arrangement of the blast-holes and the explosive charges. [ABSTRACT FROM AUTHOR]

To investigate the mechanical properties and fracture mechanism of rocks containing multiple flaws after freeze–thaw (F-T) treatment, sandstone specimens with multiple flaws were prepared and subjected to F-T treatment and uniaxial compression tests. The global strain field on the specimen surface during the loading process was calculated using the digital image correlation (DIC) method, and four grayscale parameters were introduced to quantitatively characterize the evolution of the strain field. Then, the differentiation rates (DRs) of these parameters were defined, and the correlation between these parameters and the rock fracture state was analyzed. The F-T cycling deteriorated the mechanical properties and increased the strain concentration of the specimens. The calculation results of the horizontal strains at the measurement points along the crack propagation path showed that the crack initiation of the specimens after F-T treatment occurred earlier, and their brittle failure characteristics were less pronounced. The specimen fracture process was successfully described by combining DIC and statistical grayscale parameters. The evolution pattern of each grayscale parameter of the specimens was generally similar before and after F-T treatment in that it exhibited disorderly fluctuation first, then steady development, and finally accelerated change. The grayscale parameters changed abruptly at the initiation of wing cracks and antiwing cracks, resulting in sharp points in the DR vs. strain curves. These points can be defined as precursor points P1 and P2 for identifying the deformation and fracture state of the rock. The F-T cycling led to the delayed occurrence of P1 and the advanced occurrence of P2. [ABSTRACT FROM AUTHOR]

To gain deep insights into the reinforcement effect of weak inclusions on jointed rock masses containing an opening, natural sandstone specimens containing multiple non-persistent joints and an opening were prepared, and two different cases, unfilled and filled openings, were considered. Digital image correlation (DIC) was applied to characterize the deformation fields of specimens during loading. Two measures extended from the DIC, the displacement vector and multivariate measure of strain dispersion, were proposed to identify and quantitatively analyze the cracking mechanism. Weak inclusions were found to improve the mechanical properties. The displacement vector fields around the newly formed cracks were calculated, and then, four types of cracks were recognized: direct tensile cracks, relative tensile cracks, shear cracks, and mixed cracks. Based on the fracture nature of cracks, nine types of crack coalescence among joints and six categories between openings and joints were summarized. The influence of weak inclusions on the cracking behavior of jointed sandstones was further clarified. Many more cracks were detected in the specimens containing a filled opening, which was validated by the fractal dimensions of the ultimate fracture surfaces. The differentiation rate of the effective variance (DREV) was defined to describe the dispersion of full-field strain data. The DREV was extremely close to 0 at the initial compacting and elastic deformation stage and then exhibited anomalous responses to cracking events. The first peak in the DREV–strain curve represents crack initiation, which can be regarded as a precursor. [ABSTRACT FROM AUTHOR]

The organic flash cycle (OFC) is a novel power cycle with small exergy loss in the endothermic process. However, the low-pressure throttle valve in the cycle has a large throttling loss. Aiming to reduce the cycle exergy loss and improve the system performance, this study constructs a new configuration named the organic flash Rankine cycle (OFRC). Using the R600/R245fa mixture as the circulating working fluid and 200 °C geothermal water as the heat source, the effects of the change in working fluid composition on the thermal properties of the OFRC were studied based on the first and second laws of thermodynamics. Then, the economic performance of the proposed OFRC was investigated and then compared with that of the conventional OFC. The results show that the OFRC system has a significant improvement in thermal performance and economy compared with the OFC system. When the mole composition of the R600/R245fa mixture is 0.5/0.5, the net output work, thermal efficiency, and exergy efficiency of the OFRC system can reach a maximum at 146.39 kW, 21.51%, and 80.94%, respectively, which are 98.2 kW, 14.43%, and 54.3% higher than those of the OFC system. The dual heaters in the OFRC system can effectively reduce loss in the endothermic process. When the R600 mole composition is 0.5 in the OFRC system, the exergy loss of the heater is only 7.42%, and the power generation cost (0.3267 $·kW−1·h−1 only) is lower than that in the OFC system. [ABSTRACT FROM AUTHOR]

• New two-stage collector coupling flat plate and parabolic trough types is designed. • Four nanofluids are added to enhance heat transfer performance of solar collector. • Cost reductions of two-stage collector are evaluated in organic Rankine cycles. • Unit cost of two-stage collector is 6.8% lower than parabolic trough collector. • Cu-oil nanofluid has the best heat transfer performance. The flat plate collector (FPC) has a low economic cost, while the parabolic trough collector (PTC) has a high heat collection temperature. To reduce costs, improve efficiency, and promote the use of solar energy, this study proposes a new two-stage solar collector that couples FPC and PTC. The main objective of this paper is to verify the performance of this two-stage solar collector when containing nanofluids. This collector drives the organic Rankine cycle (ORC) with four nanoparticles (Cu, CuO, TiO 2 , and Al 2 O 3) in the oil heat transfer fluid. The FPC outlet temperature in the two-stage solar collector is optimized, the exergy of ORC is analyzed, and the economics of the new system using nanofluid are calculated and compared with those of the new system without nanofluid. Results show that Cu-oil outperforms the other nanofluids in terms of heat transfer. At a rated output power of 5 kW, the new two-stage solar collector with 5 % Cu-oil can reduce economic costs by 6.8 % compared with a single PTC. Meanwhile, the ORC with a two-stage solar collector using 5 % Cu-oil reduces the economic costs by 5.7 % compared with the ORC equipped with PTC without nanofluid. The new system has a minimum payback period of 17.3 years, and increasing the output power of the ORC is beneficial for reducing the investment payback period of the system. [ABSTRACT FROM AUTHOR]

• Technical-economic evaluation was conducted for various PV tracking systems. • Analysis was performed on six different latitude regions in China. • Several tracking systems have better economic viability than fixed-tilt systems. • Introduction of carbon trading increases investment viability of tracking systems. Renewable energy generation plays a crucial role in mitigating global climate change and achieving carbon peak and carbon neutrality targets. Photovoltaic (PV) power is an important component of renewable energy generation. With China's commitment to meet its dual carbon targets on time, the application of PV tracking systems, which significantly increase the amount of PV power generated, has become a trend for the future. However, the suitability of PV tracking systems varies significantly between regions. This paper aims to assess and compare the technical and economic performance of PV systems using different PV tracking systems in six different latitude regions in China under the consideration of carbon trading. By utilizing the PVsyst software, the monthly/yearly unit electricity generation of different tracking systems in each region is calculated. Furthermore, the technical and economic performance of these systems is assessed by computing the levelized cost of electricity (LCOE), net present value (NPV), and discounted payback period (DPP) with and without carbon benefits, taking into account sensitivity analyses. The results indicate that the dual-axis tracking (DAT) system achieves the highest electricity generation, providing a gain of 17.94 %–31.52 % compared to the fixed-tilt (FT) system. The horizontal axis tracking North-South (HATNS) system and the tilted-axis tracking (TAT) system are probably the most economically viable systems in areas with high radiation levels, with NPV values 2.02 %–25.55 % and 6.44 %–19.45 % higher, respectively, compared to the FT system. The introduction of carbon benefits significantly increases the economic viability of all tracking systems. [ABSTRACT FROM AUTHOR]

Displacement prediction is critical for the early detection of landslides, and the empirical, statistical, and machine learning models have been commonly used. In the Three Gorges reservoir area (TGRA), many landslides experience step-like deformations due to the periodic change of influencing factors. In this study, a novel and dynamic model is proposed to predict the displacements of step-like landslides. Two typical landslides in the TGRA are taken as case studies. Variational mode decomposition (VMD) is used to decompose the cumulative displacements into stochastic, periodic, and trend components. The influencing factors are decomposed into low-frequency and high-frequency components. Two principles, including the physical connotation and minimum sample entropy, are employed to optimize the VMD parameters. The trend displacement is fitted and predicted by a polynomial expression with an optimized order, and the periodic and stochastic displacements are dynamically modeled by the bidirectional long short-term memory (LSTM) model. The cumulative displacement prediction is the addition of the three displacement components. The proposed model has been shown to exhibit superior performance in the displacement prediction of step-like landslides. To achieve acceptable prediction, a size ratio between the training and testing datasets greater than or equal to five is recommended. The min–max and zero-mean normalizations are applicable to the data preprocessing of this work. [ABSTRACT FROM AUTHOR]

Physical modeling of rock masses containing complex fracture geometries is an important but very challenging task in rock mechanics and rock engineering. In this work, a novel integration of 3D printing and water-soluble casting is presented for the preparation of rock-model specimens with fracture networks, which is similar to the lost-wax casting process. The fracture network is created with water-soluble polyvinyl alcohol (PVA) material by 3D printing. The intact rock matrix is prepared with cement paste. Uniaxial compressive tests combined with the digital image correlation (DIC) technique are conducted to investigate the mechanical properties and failure process of the prepared rock-model specimens. The differentiation rate of the effective variance is defined to recognize the precursory anomalies during the loading process. The mechanical anisotropy is further investigated by a series of rotated models. The results show that the proposed methodology has distinct advantages for replicating rocks with complex fracture geometries in terms of high accuracy for fabricating fracture networks, high repeatability of mechanical properties, and high strength and brittleness of rock matrices. Due to the presence of complex fracture geometries, the nonlinear mechanical responses of the fractured rock-model specimens, including strain-softening and anisotropy, are observed in our experiments. [ABSTRACT FROM AUTHOR]

Organic flash cycle is an important way to achieve geothermal power generation. Double-stage organic flash cycle (DOFC) has two flash processes, remarkably enhancing the heat matching effect of heat absorption process compared to single-stage type. Working fluid is an important factor influencing the performance superiority of DOFC. However, traditional organic fluids are being phased out due to environmental requirements, the new-type hydrofluoroolefins are emerging with good environmental performance. For new-type hydrofluoroolefins, the characteristics of DOFC are unclear and its advantages over single-stage type need to be quantified. This work evaluates the thermodynamic, exergy and economic performance of DOFC using ten eco-friendly hydrofluoroolefins. Influences of key parameters on thermodynamic and economic performance are analyzed. For hydrofluoroolefins, the superiorities of DOFC over single-stage type were quantitatively evaluated. Results show that the advantages of DOFC will become greater at the lower heat source temperature and the lower critical temperature of hydrofluoroolefins. R513A shows the greatest advantages of DOFC over single-stage type, and the maximum relative increment in the net power is 111.2 % and the maximum relative decrement in specific investment cost is 49.5 %. The optimum hydrofluoroolefin is R1366mzz(Z) with a net power of 348.29 kW and a specific investment cost of 7.88 k$·kW−1. [ABSTRACT FROM AUTHOR]

Organic Flash Cycle (OFC) is a promising waste heat utilization technique for low and medium temperature. However, throttling exergy loss in the flash and throttling processes substantially reduces the efficiency of basic organic flash cycle (BOFC). The regenerative organic flash cycle (ROFC) can avoid the exergy loss in the throttling process and enhance the thermodynamic performance of OFC. This paper proposes a novel dual-heater regenerative organic flash cycle (DROFC), which can obtain more power output by reducing the flash process exergy loss and eliminating the mixer exergy loss in ROFC. The thermo-economic performance of DROFC was compared with BOFC and ROFC to evaluate its application potential. Eight low-GWP pure organic fluids were selected and the heat sources were 100–200 °C. Results indicate that DROFC could produce more net power output than BOFC and ROFC with a lower specific investment cost. Specifically, with R600 as an example, the maximum net power output percentage gain of DROFC is 41.19% and 29.09%, respectively. DROFC is more suitable for application scenarios where the heat source temperature exceeds the critical temperature of organic fluid. To balance the net power output and levelized cost of electricity, Hydrocarbons with a high critical temperature are appropriate for DROFC. • Novel dual-heater regenerative organic flash cycle (DROFC) is proposed. • Thermo-economic performance of three systems is analyzed and compared. • Multi-objective optimization is used to weigh thermodynamic and economic indexes. • Maximum percentage gain in net power output of DROFC is 41.19%. • Hydrocarbons with high critical temperatures are more suitable for DROFC. [ABSTRACT FROM AUTHOR]

Shear-box experiments, Rock Failure Process Analysis (RFPA) simulations, and box-counting fractal analysis on rock-like models are conducted to investigate the influence of intermittent artificial crack density on the shear fracturing and fractal behavior of rock bridges in jointed rock slopes. The artificial crack geometry of the conceptual rock bridge model is a combination of two edge-notched artificial cracks and imbedded artificial cracks with different intermittent artificial crack densities. By numerical shear-box tests, deep insight into the mesoscopic mechanism of crack evolution is gained, and the simulated failure patterns are in accordance with experimental results. Three types of failure patterns are identified: shear mode, mixed shear/tensile mode, and tensile mode. The RFPA simulations demonstrate that macroscale shear cracks form as damage belts consisting of many tensile/shear mesocracks, as typically observed in microscopic experimental work. The failure pattern is mostly influenced by the intermittent artificial crack density, whereas the peak shear strength is related to the failure pattern. As the intermittent artificial crack density increases, the failure pattern changes from shear mode to mixed shear/tensile mode and then to tensile mode, resulting in a decrease in the peak shear strength. The regression analysis shows that the relationship between the peak shear strength and intermittent artificial crack density can be expressed by an exponential decay model. Furthermore, digital image processing and box-counting fractal analyses are performed on the shear fracture surfaces of the physical and numerical models to describe the fractal behavior. The relationships between the fractal dimension and peak shear strength are analyzed, and strong correlations that display an exponential decay function are found. [ABSTRACT FROM AUTHOR]

Abstract Cobalt hydroxides, Co(OH) 2 , was in situ fabricated taking metal-cobalt as both conductive substrate and cobalt source by a facile hydrothermal method. It is found that the Co(OH) 2 morphologies is highly depended on the solution including H 2 O, LiOH, NaOH and KOH. All the Co(OH) 2 shows potential application for non-enzymatic glucose detection. Especially, nanosheets after hydrothermal treating Co foil in KOH shows linearly amperometric signals to glucose concentration up to 3 mM with a detection limit of 0.5 μM, fast response time (6.5 s–100 μM), and an excellent sensitivity of 1646 μA mM−1cm−2 (R2 = 0.9904). These findings provide a new opportunity to directly fabricate Co(OH) 2 on Co foil for glucose detection, which does not only simplify the electrode fabrication procedure to enhance the electron transport, but also favor the full utilization of active nanocatalysts to improve the electrochemical performance. Highlights • Co(OH) 2 was in situ fabricated using metal-cobalt as substrate and cobalt source. • The Co(OH) 2 morphologies is highly depended on the solution. • Co(OH) 2 nanosheets were obtained by hydrothermal treating Co foil in KOH. • Co(OH) 2 nanosheets shows excellent performances for glucose detection. [ABSTRACT FROM AUTHOR]

Abstract Arboviruses have caused significant global health concerns during the past decade. In this regard, continuous viral surveillance is essential to timely identify emerging arboviruses and other novel viruses. Here, a novel isolate of Phasi Charoen-like virus (PCLV Zhanjiang01) was identified from field-captured Aedes aegypti mosquitoes in Zhanjiang by next generation sequencing. Phylogenetic analysis suggested that PCLV Zhanjiang01 belonged to the genus Phasivirus in the family Phenuiviridae. The presence of PCLV in three batches of Aedes aegypti confirmed its high prevalence in nature. Further detection of PCLV in progenies and adult males suggested vertical transmission in mosquitoes. In parallel, PCLV was detected from multiple organs indicating its broad tissue distribution in the infected mosquitoes. To the best of our knowledge, this is the first report of PCLV in China. Our results expanded the global biogeographic distribution of PCLV. Further investigations of PCLV on the arboviral transmission and control strategies are warranted. Highlights • This is the first discovery of Phasi Charoen-like virus (PCLV) in wild Aedes aegypti in China. • PCLV was highly prevalent in wild Aedes aegypti but not observed in Aedes albopictus or Culex quinquefasciatus. • Detection of PCLV in male mosquitoes and progenies suggested a vertical transmission in infected mosquitoes in nature. • PCLV was broadly disseminated in multi organs in infected Aedes aegypti. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mechanical properties of sand 3D-printed specimens are similar to those of soft rocks. • A multivariate measure is proposed to quantify the strain dispersion. • Variation in the multivariate measure is found to be closely related to the crack type. • A strain dispersion based criterion for crack initiation identification is proposed. Crack identification in brittle rocks is a challenging problem in rock mechanics. To represent the details of jointed rock masses, rock-like specimens containing inclined joint sets were generally prepared by three-dimensional (3D) printing using sand. Digital image correlation (DIC) was employed for full-field deformation measurement during loading. The results show that the sand 3D-printed specimen has distinct advantages in the preparation of jointed rock masses. DIC was extended to measure the displacement vector field around newly propagated cracks. Two types of cracks are recognized: tensile and shear cracks. Two different coalescence patterns are classified: step-path failure and planar failure. A covariance matrix-based multivariate measure, the rate of effective variance change (REVC), was proposed to quantify the dispersion of strain data. The variation in the strain dispersion measure was found to be closely related to the crack type. For the first occurrence of tensile and shear cracks, the rates of mutation (RMs) are within the ranges of 1.56–3.42 and 14.54–86.44, respectively, which can be considered a new crack identification criterion. A virtual extensometer method based on DIC was established to interpret the variation mechanism of the REVC associated with different crack types. [ABSTRACT FROM AUTHOR]

The composite material of Ni(OH) 2 /biomass carbon have been prepared by a facile “carbonization–activation” procedure from Jackfruit peel and a subsequent water-bathing precipitation process. The biomass carbon material after activation (AC) is constituted of small particles and achieves a large specific surface area of 1602 m 2 /g. After decoration of Ni(OH) 2 nanosheets, the Ni(OH) 2 /AC composites were investigated the microwave absorption performances in 2–18 GHz. The maximum reflection loss of the Ni(OH) 2 /AC composites reached −23.6 dB at 15.48 GHz with a thickness of 6 mm. Moreover, the fundamental mechanism based on conductivity, the polarization and defects is discussed. The present investigation offers a new possibility for the biomass based fabrication of potential microwave absorbing materials. [ABSTRACT FROM AUTHOR]

• The effect of the intermittent opening density on sand 3D printed rock-like is studied. • The crack types and coalescence types are identified by velocity vector analysis. • A DIC-based damge evaluation is proposed to explore the damage evolution of rock. • Mechanical interpretation of the coalescence type is performed using RFPA simulation. To investigate the influence of intermittent opening density on the mechanical behavior and fracture characteristics of rock, sand 3D-printed specimens containing different opening numbers are prepared using quartz silica sand and furan resin adhesive as printing substrates. Uniaxial compression testing is performed on these rock-like specimens. Based on digital image correlation (DIC) technology, a methodology for identifying crack types and evaluating rock damage is proposed to quantify the mechanical mechanism of crack evolution during loading. The experimental results are verified and explained using the rock failure process analysis (RFPA) code. The results show that with increasing intermittent opening density, the stress–strain curves of the specimens are similar. Meanwhile, the increase in intermittent opening density causes the stress field distribution of the specimen to change, which in turn leads to a decrease in the uniaxial compressive strength and elastic modulus. The types of cracks around the opening can be grouped into tensile cracks (T) and shear cracks (S), and the coalescence modes of the rock bridge between the openings can be grouped into shear coalescence (C 1) and traction coalescence (C 2). As the intermittent opening density increases, the coalescence type between openings changes from C 1 to C 2 , and the overall failure pattern is converted from tensile-shear failure to tensile failure. The damage factor (D f) evolution is closely related to the intermittent opening density of the specimens. A one-way exponential decay correlation between the stress ratio and the damage factor is found. The above study is expected to deepen the understanding of the deformation and fracture mechanism of rock masses with openings and to provide a reference for the application of 3D printing technology in the rock mechanics field. [ABSTRACT FROM AUTHOR]

• Quantified the effect of the slope, inflow rate and scouring times on soil loss of spoil tips. • Rill depth was the best rill morphological parameter for evaluating rill erosion of spoil tips. • Shear stress was the best hydrodynamic parameter for predicting rill erosion of spoil tips. The soil erosion of spoil tips seriously threatens the safety of people's lives and property and the surrounding ecological environment. Rill erosion is an important cause of water and soil loss in spoil tips. This study investigated the rill erosion on spoil tip slopes, the morphological changes of rills and the mechanisms of rill erosion. A field runoff plot (5 m long, 1 m wide and 0.5 m deep) with three inflow rates (1.6, 2 and 2.4 mm min−1) and three typical slopes (28°, 32° and 36°) was used for runoff simulation experiments. Results showed that inflow rate was the most important factor affecting soil erosion, which contributed 68.87% and 60.54% to the runoff rate and soil loss rate, respectively. Rill development has three stages: formation, development and adjustment. The overall predominance of parallel-shaped rills suggested that rill formation was dominated by concentrated runoff. Inflow rate exerted the greatest effect on the average rill width and average rill depth, with contribution rates of 73.11% and 60.26%, respectively. Meanwhile, slope exerted the greatest effect on the rill width-to-depth ratio, with a contribution of 60.45%. The average rill depth was the best indicator of rill morphology for evaluating rill erosion. Reynolds number was the best hydraulic parameter for predicting rill erosion. Flow shear stress was the best hydrodynamic parameter to describe rill erosion mechanism, with a critical value of 1.98 Pa. These results contributed to elucidating the rill erosion mechanism of spoil tip slope and provided a scientific basis for its soil erosion control. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 18 polychlorinated biphenyls (PCBs) were measured in 11 varieties of food groups collected from retail market of Shenzhen, Guangdong province, China from 2004 to 2006. PCDD/Fs and PCBs dietary intake from varies food for the local population was estimated in the study. Methods: Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (PCBs) as well as 6 marker PCBs were measured in 11 varieties of food groups in total 110 food samples by isotope dilution HRGC/HRMS. PCDD/Fs and PCBs dietary intake for local population was estimated using total WHO-TEQ concentration and different food consumption amount of the local population. Results: The median WHO-TEQ concentrations of sum of PCDD/Fs and DL-PCBs varied from 0.0093 pg/g (parts per trillion) in vegetable to 9.89 pg/g in fish. Fish was followed by egg 2.46, chicken 1.73, beef 0.94, mutton 0.82, duck 0.39, pork 0.37, milk powder 0.25, vegetable oil 0.076, cereals 0.022 pg/g and vegetable. The monthly intake of PCDD/Fs and PCBs were 40.9 pg WHO-TEQ/kg b.w. for local population. Sum of fish, livestock, and poultry contributed 77% to the Estimated Monthly Intake (EMI) in local population. Conclusion: Estimated dietary intake of PCDD/Fs and DL-PCBs for local population was below the provisional tolerable monthly intake(PTMI) set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). [Copyright &y& Elsevier]

• Correlation among fracturing, energy conversion and frictional heating is analyzed. • Failure process is identified by the strain localization in the strain field. • Precursors for rock failure are identified by the evolution law of strain field. • Brittleness index increases with increasing post-peak energy conversion rate. • A high-temperature zone appears around shear fracturing zone. Experiments on sandstone specimens are conducted to investigate the mechanical, energy conversion and frictional heating characteristics of locking sections in two types of large-scale rockslides. The flaw geometry of the conceptual model is a combination of two preexisting flaws and a locking section. A deep insight into the failure mechanism of locking sections is gained by using digital image correlation (DIC) technology, thermal imaging technology, and thermodynamics theory. Two different types of failure patterns are reproduced in our experiments: the retaining wall type and step-path type, which are shear and tensile in nature, respectively. The results obtained by DIC measurements demonstrate that the failure process of a locking section is a progressive development of strain localization zones, which actually reflects the displacement discontinuity when a crack propagates. The variance and differentiation rate are defined to provide differentiation and precursory information on the deformation and fracturing process of a locking section. From the energy point of view, the strain energy conversion (accumulation, dissipation and release) during loading significantly influences the failure pattern of the locking section. The faster the post-peak conversion rate of strain energy, the more violent is the post-peak fracturing behavior of the locking section. A strong positive correlation is found between the post-peak conversion rate of strain energy and the brittleness index. Furthermore, thermal imaging technology is applied to describe the frictional heating behavior. The correlation among the failure pattern, energy conversion, and thermomechanical response is analyzed. The frictional heating phenomenon is related to the shear failure, and a fast post-peak conversion rate of strain energy occurred along the locking section. [ABSTRACT FROM AUTHOR]