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• A 3-D numerical model including a 2-D random rough surface was established. • Providing a unique perspective in terms of a solidified cloud map. • The mechanical mechanism such as solidified resistance was suggested systematically. The spontaneous spreading of water droplets on a low-temperature solid surface is ubiquitous in nature and critical to numerous industrial applications, but its mechanism remains elusive. In this study, a three-dimensional (3-D) computational fluid dynamics (CFD) model, which intergrows a random rough surface, is proposed to investigate the effects of droplet impact dynamics on hydromechanical solidification. The 3-D CFD model reveals important physical details that cannot be captured easily by a 2-D axisymmetric model or by practical experiments. For instance, the established model provides a unique perspective on the complex hydromechanical solidification behaviours of a single falling droplet in terms of impact dynamic parameters and a solidified cloud map. In particular, the two-phase interfacial resistance derived from the liquid-to-solid transition is systematically discussed, demonstrating different wetting states for spreading droplets on a random rough surface. Moreover, the solidified cloud map suggests that surface wettability, substrate temperature, and droplet impact velocity have nonnegligible effects on phase transition solidification. This work may expand our understanding of droplet dynamic solidification on cold superhydrophobic surfaces and provide a great reference for related subsystems referring to anti-icing/frosting or self-cleaning technologies. [ABSTRACT FROM AUTHOR]

In this study, chopped natural bamboo fibers were successfully added in the benzoxazine matrix by the hot-pressing method to fabricate environmentally friendly bio-composite. The mechanical behaviors and failure mechanisms of neat benzoxazine matrix and its bamboo fiber composite under different tensile strain rates (quasi-static, 35/s and 110/s) were comparatively investigated using SHTB device (split-Hopkinson tensile bar), high-speed camera, DIC method (digital image correlation), and SEM observation (scanning electron microscopy). The results showed the composite exhibited 30.02% and 25.21% higher strength than that of neat benzoxazine under strain rates of 35/s and 110/s, respectively. However, under quasi-static tensile loading, the tensile strength of the composite was not higher than that of neat benzoxazine. The SEM and high-speed camera images showed the bamboo fibers displayed different reinforcing mechanisms under different strain rates. The chopped bamboo fibers could strengthen the composite effectively under dynamic tensile loadings. However, under quasi-static loading, the tensile strength of the composite was largely determined by the potential defects (such as small bubbles, pores, and fiber agglomerations) in the composite. [ABSTRACT FROM AUTHOR]

As today's Internet of Things (IoT) applications are becoming more complicated and intelligent, IoT devices alone can no longer well support the ever-increasing demand for powerful computation and high energy efficiency. Mobile Edge Computing (MEC) and 5G technology emerge as promising solutions, which enable IoT tasks to be offloaded to edge servers for effective processing. Though desirable, there however exists a mismatch between the massive IoT task workloads and limited wireless bandwidth, making it challenging to achieve an optimal offloading strategy at the mobile edge, e.g., the base station (BS) server. In this paper, we aim to migrate the most suitable offloading tasks to fully obtain the benefits of the MEC task offloading. We first formulate the task offloading model as an optimization problem, and theoretically prove the NP-hardness in achieving the optimal solution. Thus, a Genetic algorithm, named M-COGA, is proposed to solve the task offloading selection in both single and multiple BS scenarios. The algorithm focuses on offloading as many tasks as possible with the maximum cost offloading. The proposed cost function takes into account both the computation overhead and energy consumption. Besides, for the multi-BS coverage scenario, we also consider the approach flexibility as well as link load balance. And an enhanced dynamic task offloading scenario is further discussed. We verify the efficiency of our algorithm under the condition of both uniform and non-uniform distribution of covered nodes. Numerical experiments demonstrate that our dynamic allocating scheme can effectively work in MEC offloading. Besides, it largely outperforms the single BS scenarios and reduces the cost of edge devices. [ABSTRACT FROM AUTHOR]

Ubiquitous deployment of networked cameras has boosted the prevalence of video analytics. Leveraging machines to automatically analyze captured videos has become the driving force behind a variety of contemporary applications. However, it is known to be resource-hungry with highly dynamic demands, which mismatches the existing monolithic cloud service deployment with coarse-grained resource allocation. Recent advances in serverless computing, which offers ultra-fast and fine-grained autoscaling, would become a game-changer. This article closely examines the potential and challenges of serverless computing in building modern video analytics applications. We accordingly present an integrated framework with geo-distributed resources, and identify the critical design issues toward its implementation. We further discuss a series of promising research directions in this field. [ABSTRACT FROM AUTHOR]

Reviews of product or stores exist extensively in online e-commerce platform which is important for customers to make decisions. For economic reasons some dishonest people are employed to write fake reviews which is also called "opinion spamming" to promote or demote target products and services. Previous researches have made use of text similarity, linguistics, rating patterns, graph relationship and other behaviors for spammer detection. They mainly utilized product review list while it is difficult to find fake reviews by glancing over product reviews in time-descending order. Meanwhile there exists lots of useful information in the list of reviews of reviewers and relationships between reviewers when reviewers commonly reviewed the same stores. We propose the concept of review group and to the best of our knowledge, it's the first time the review group concept is proposed and used. Review grouping algorithm is designed to effectively split reviews of reviewer into groups which participate in building novel grouping models to identify both positive and negative deceptive reviews. Several new features which are language independent based on group model are constructed. Additionally, we explore the collusion relationship between reviewers to build reviewer group collusion model. Evaluations show that the review group method and reviewer group collusion models can effectively improve the precision by 4%–7% compared to the baselines in fake reviews classification task especially when reviews are posted by professional review spammers. [ABSTRACT FROM AUTHOR]

Six new 2α-hydroxy ursane triterpenoids, 3α-cis-p-coumaroyloxy-2α,19α-dihydroxy-12-ursen-28-oic acid (1), 3α-trans-p-coumaroyloxy-2α,19α-dihydroxy-12-ursen-28-oic acid (2), 3α-trans-p-coumaroyloxy-2α-hydroxy-12-ursen-28-oic acid (3), 3β-trans-p-coumaroyloxy-2α-hydroxy-12,20(30)-ursadien-28-oic acid (4), 3β-trans-feruloyloxy-2α-hydroxy-12,20(30)-ursadien-28-oic acid (5), and 3α-trans-feruloyloxy-2α-hydroxy-12,20(30)-ursadien-28-oic acid (6), along with eleven known triterpenoids (7–17), were isolated from the leaves of Diospyros digyna. Their chemical structures were elucidated by comprehensive analysis of UV, IR, HRESIMS, and NMR spectra. All the isolated compounds were evaluated for their PTP1B inhibitory activity. 3β-O-trans-feruloyl-2α-hydroxy-urs-12-en-28-oic acid (13) showed the best inhibition activity with an IC50 value of 10.32 ± 1.21 μM. The molecular docking study found that the binding affinity of compound 13 for PTP1B was comparable to that of oleanolic acid (positive control). [ABSTRACT FROM AUTHOR]

Recent years have witnessed an explosive growth of online shopping, which has posted unprecedented pressure on the logistics industry, especially the last mile parcel delivery. Existing solutions mostly rely on dedicated couriers, which suffer from high cost and low elasticity when dealing with a massive amount of local addresses. Advances in the Internet of Things, however, have enabled vehicle information to be readily accessible anytime anywhere, forming an Internet of Vehicles (IoV), which further enables intelligent vehicle scheduling and management. New opportunities therefore arise toward efficient and elastic last mile delivery for smart cities. In this article, we seek novel solutions to improve the last mile parcel delivery with crowd intelligence. We first review the existing and emerging solutions for last mile parcel delivery. We then discuss the advances of the ride-sharing- based delivery mechanism, identifying the unique opportunities and challenges therein. We further present Car4Pac, an IoV-enabled intelligent ride-sharing-based delivery system for smart cities, and demonstrate its superiority with real trace-driven evaluations. [ABSTRACT FROM AUTHOR]

The widespread adoption of video surveillance systems in public security and network security domains has underscored the importance of video anomaly detection as a pivotal research area. To enhance the precision and robustness of anomaly detection, this manuscript introduces an innovative method for video anomaly detection. The approach begins with the application of multi-scale feature extraction technology to capture visual information across varying scales in video data. Leveraging the Spatial Pyramid Convolution (SPC) module as the cornerstone for multi-scale feature learning, the study addresses the impact of scale variations, thereby augmenting the model’s detection capabilities across different scales. Furthermore, a Weakly Supervised Data Augmentation Network (WSDAN) module is incorporated to facilitate attention-guided data augmentation, enhancing the richness of input images. These augmented images undergo training with the U-Net network to elevate detection accuracy. Additionally, the integration of the improved Convolutional Block Attention Module (CBAM) into the base U-Net architecture enables end-to-end training. CBAM dynamically adjusts feature map weights, allowing the model to concentrate on anomaly relevant regions in the video while suppressing interference from non-anomalous areas. To assess anomalies, the paper employs the Peak Signal-to-Noise Ratio (PSNR) between predicted and original frames, normalizing PSNR values for anomaly identification. The proposed method is then evaluated using publicly available datasets CUHK Avenue and UCSD Ped2, with results visually presented. Experimental findings showcase Area Under the Receiver-Operating Characteristic Curve (AUC) values of 86.2% and 97.9% for these datasets, surpassing comparative methods and confirming the effectiveness and superiority of the proposed approach. [ABSTRACT FROM AUTHOR]

The present work investigated the effects of non-ionic surfactant treatment on the dispersibility, surface chemistry and structure of carbon nanotube (CNT) particles. Subsequently, the fracture experiments of as-prepared epoxy/CNT@X nanocomposites were carried out under quasi-static and dynamic loading conditions. By simply introducing the steric repulsive force between CNT@X filler and epoxy matrix, improved mode-I critical-stress-intensity factor (K Ic) and dynamic crack initiation toughness (K I i d) of the epoxy/CNT@X nanocomposite were simultaneously obtained without compromising other desired physical properties, such as electrical properties and electro-thermal behavior. In the case of SHPB impact loading, high-speed imaging along with digital-image-correlation (DIC) technology was utilized to determine dynamic fracture parameters. The results showed a notable reinforcement for the epoxy/CNT@X nanocomposite category, producing maximum increase of ~79% and ~153% in K Ic and K I i d values relative to epoxy/CNT nanocomposite at such maximum content of 1.0 wt%, respectively. The most delayed crack initiation time (59.9–68.4 μs) and slowest crack-tip velocity (229 ± 28 m/s) were also observed in the epoxy/CNT@X_1.0 case. These results may be explained by improved dispersibility and interfacial adhesion after surfactant treatment. • Improved fracture behaviors of nanocomposite with surfactant treatment were obtained. • An optical DIC method along with high-speed imaging was used to extract dynamic SIFs histories. • Introduced steric repulsive force improved the dispersibility of CNTs throughout the matrix domain. • Improved dispersibility and interfacial adhesion could provide stronger interfacial interactions. • Physical adsorption of the surfactant molecule did not compromise the conductive functionalities of CNT networks. [ABSTRACT FROM AUTHOR]

Icing is a multiphase/multiscale/multiparameter physical process, and is of frequent occurrence when suitable conditions with temperature, pressure and humidity are met. In the present work, we prepared a series of PDMS-matrix nanocomposite films with different SWCNT contents, which were endowed with hydrophobicity based on the low-surface-energy PDMS matrix and the conductivity on the SWCNT filler. Furthermore, by etching the pillar-textured structure on its surface, the nanocomposite with 5.0 wt% SWCNT was given the superhydrophobicity. These nanocomposites can be easily switched from a hydrophobic anti-icing mode to an electro-thermal deicing mode by supplying a low voltage. Using non-contact infrared thermometry, we presented an analysis of the freezing phase transition process of a single water droplet on cooling surfaces with different wettability, and investigated their ice nucleation rate and macroscopic growth velocity on these surfaces. The ice-retarding capability of superhydrophobic nanocomposite surface subjected to lots of condensed droplets was also confirmed, and understanding in light of weak contact interaction with droplets. Also under consideration is the icephobicity after freezing in terms of ice shear strength. In addition, we performed a statistical analysis about the Joule heat distribution on nanocomposite surface, the results of which demonstrated that the nanocomposite could supply a suitable heating function for active deicing, demonstrating with an energy-input deicing experiment subsequently. [ABSTRACT FROM AUTHOR]

Four panels with a semicircular arch structure comprised of glass-fiber-reinforced polymer (GFRP) laminates are subjected to low-velocity impact, compression-after-impact (CAI), and quasi-static compression tests. Mechanical response and the failure mechanism of the complex structure are investigated with the assistance of a three-dimensional digital image correlation (3D-DIC) system and numerical simulation based on Hashin’s failure criteria in Abaqus software. The results show that the addition of a semicircular arch can absorb more incident energy during the impact process. The failure modes of the panels are depended on the semicircular arch dimension, and excellent anti-impact performance is found in the semicircular arch with a diameter close to the impactor. Meanwhile, the CAI strength is increased with the semicircular arch size. [ABSTRACT FROM AUTHOR]

In this study, bamboo and glass fibers were successfully added into bisphenol A–aniline-based benzoxazine resin by hot pressing method. The effect of water absorption on the mechanical properties of the neat benzoxazine and its composites was studied. The composites prepared in this study has been proved to exhibit better water resistance than some conventional natural fiber/polymer composites due to good hydrophobicity of the benzoxazine matrix. From the mechanical tests, the tensile performance of both neat benzoxazine and the composites degraded seriously after prolonged immersion in water. However, neat benzoxazine and the composites maintained relatively higher residual flexural properties (residual mechanical properties refer to the ratio of strength and modulus of the saturated samples to that of the nonaged samples) after 20 days of water immersion. The effect of water molecules on the fracture surface morphologies of the composites was studied using a scanning electron microscope (SEM). The SEM images showed that the interfacial bonding between fibers and the matrix degraded seriously due to the attack of water. [ABSTRACT FROM AUTHOR]

Bamboo fibers demonstrate enormous potential as the reinforcement phase in composite materials. In this study, in order to find suitable NaOH concentration for bamboo fiber treatment, bamboo fibers were treated with 2 wt.%, 6 wt.% and 10 wt.% NaOH solutions for 12 h, respectively. We determined that 6 wt.% NaOH treated bamboo fibers were optimal for the fabrication of bamboo fiber composites by single fiber tensile test, single fiber pull-out test, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The short length bamboo fibers treated with 6 wt.% NaOH solutions were well dispersed in the epoxy matrix by a new preparation method. The effect of fiber content and fiber length on the mechanical behavior of bamboo fiber reinforced epoxy composites was investigated. The results confirmed that fracture toughness and flexural modulus of the composites monotonically increased with fiber length and content. However, for all samples, composites showed negligible difference on the flexural strength. The fracture surfaces of the composites were observed by SEM, revealing that fiber breakage, matrix cracking, debonding, and fiber pull out were major failure types. In addition, thermogravimetric analysis (TGA) was carried out to investigate the thermal behavior of both bamboo fibers and composites. [ABSTRACT FROM AUTHOR]

Lotus leaves and rose petals are the two typical natural examples with superhydrophobicity, also known as the lotus effect and petal effect, respectively. It is generally recognized that the hierarchical structures on their surfaces are responsible for the lotus effect and petal effect. However, the relations between surface geometries and the corresponding wetting states have not been understood completely. In this paper, a 3-D model is built to thermodynamically analyze the wetting behavior of hierarchical structured surfaces. The free energy (FE) and free energy barrier (FEB) of different wetting states are analyzed in detail. Furthermore, equilibrium contact angle (CA), receding and advancing CAs, as well as contact angle hysteresis (CAH) can be predicted by this approach. More importantly, the critical Nano pillar height used for characterizing the transitions between the two wetting states is clearly defined in terms of geometric parameters of solid surfaces, and the final stable wetting state dominated by surface roughness and chemical composition can be determined based on the obtained results. The approach presented in this study can also be used as a guidance for fabricating superhydrophobic surfaces. [ABSTRACT FROM AUTHOR]

The current work studied the physical modification effects of non-covalent surfactant on the carbon-particle-filled nanocomposite. The selected surfactant named Triton™ X-100 was able to introduce the steric repelling force between the epoxy matrix and carbon fillers with the help of beneficial functional groups, improving their dispersibility and while maintaining the intrinsic conductivity of carbon particles. Subsequent results further demonstrated that the physically modified carbon nanotubes, together with graphene nanoplates, constructed an effective particulate network within the epoxy matrix, which simultaneously provided mechanical reinforcement and conductive improvement to the hybrid nanocomposite system. For example, the hybrid nanocomposite showed maximum enhancements of ~75.1% and ~82.5% for the quasi-static mode-I critical-stress-intensity factor and dynamic compressive strength, respectively, as compared to the neat epoxy counterpart. Additionally, the fine dispersion of modified fillers as a double-edged sword adversely influenced the electrical conductivity of the hybrid nanocomposite because of the decreased contact probability among particles. Even so, by adjusting the modified filler ratio, the conductivity of the hybrid nanocomposite went up to the maximum level of ~10−1–100 S/cm, endowing itself with excellent electro-thermal behavior. [ABSTRACT FROM AUTHOR]

Considerable efforts had been devoted to investigating numerically the droplet impact dynamics on a superhydrophobic surface, whereas most of these numerical simulations were restricted to the two-dimensional (2D) axisymmetric coordinate system with the one-dimensional (1D) substrate surface. In this work, a three-dimensional (3D) computational fluid dynamics (CFD) model, which intergrew a 2D random rough surface, was proposed to investigate the droplet impact dynamics, and the multi-phase flow issue was solved by the Navier–Stokes equations. It is remarkable that the 3D CFD model revealed several significant dynamic details that were not easily captured in a 2D axisymmetric coordinate system or practical experiments. For instance, the 3D CFD model provided a unique perspective to understand the varying dynamic behaviors of impinged droplet in terms of the velocity streamline and dynamic viscosity analyses. Herein, the dynamic viscosity diagram revealed that the sprawl droplet on the 2D random rough surface was classified as the Cassie state, while as the Wenzel state for the smooth surface, which also explained the better bouncing behaviors of the droplet from the random rough surface. Accordingly, we suggested a visual way to evaluate the solid–liquid contact area surrounded by the triple-phase contact line. The effects of finger protrusion and central cavity growth from the sprawl droplet on the vortex generation were further analyzed on the ground of the velocity amplitude distribution and streamline data. The present work can provide early guidance to inquire into the impact dynamics of droplets on the random rough surface. [ABSTRACT FROM AUTHOR]

The precision maintenance of delaminated carbon-fiber-reinforced polymer composites calls for the high demand of continuous, in situ monitoring of the damage-repair process along with the in-service status of the repaired region. Moreover, the repaired region faces a high risk of re-damage; therefore, in-service monitoring is highly desired. However, the current repair process lacks the in situ monitoring function, leading to the mechanism and evaluation of the repair approach being unclear. Here, we implanted multi-wall carbon nanotubes (MWCNTs) at the interface between the carbon fiber and resin matrix of the damaged region to achieve in situ monitoring of the repair, compression, and seawater-immersion processes. By depositing both the coupling agent and MWCNTs at the interfaces, a high recovery efficiency of 85% was achieved, which was independent of the delamination pattern shapes. The electric resistance changes of MWCNT-modified panels could effectively identify the resin permeation and solidification processes and could be used to in situ monitor the structural health of the repair region when it is subjected to the compression and seawater immersion tests. This strategy, combining high-efficient repair and precision maintenance, demonstrates potential in the structural applications of carbon-fiber-reinforced polymer composites. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced polymers are important constituents of aerospace materials. However, due to the inert surface of CFs, their interfacial property is relatively weak, which severely hinders their practical applications. Here, we deposited multi-walled carbon nanotubes (MWCNTs) along with a coupling agent on the surface of carbon fiber to improve the interfacial properties of the carbon fiber/resin. Via a simple dip-coating method, the MWCNTs were uniformly distributed on the CF surface with the assistance of the pre-coated coupling agent. The interfacial shear strength between the fiber and the matrix was significant enhanceed when the CF was loaded with the coupling agent and the MWCNTs. In addition, the MWCNTs were used as sensors to in-situ monitor the interfacial state in order to elucidate the interfacial strengthening mechanism. It revealed that the collaborative contribution of the coupling agent and the MWCNTs in the interphase region is the key to the high interfacial strength. [ABSTRACT FROM AUTHOR]

Glass fiber/polymerized cyclic butylene terephthalate (GF/pCBT) and its nanosilica-modified thermoplastic composites were manufactured via vacuum-assisted molding pressing process. Subsequently, the effects of temperature and nanosilica fillers on the macroscopic mechanical behavior of glass fiber-reinforced pCBT composites were discussed. Failure morphologies of specimens were observed by scanning electron microscopy (SEM). Experimental results show that pure GF/pCBT composites have good mechanical properties, whereas their half-strength degradation temperature (T S = 0.5) is relatively lower. It is also found that nanosilica-modified composites have higher heat resistance performance, and T S = 0.5 point of the modified composites enhanced by 10°C. SEM observations show that the smooth fracture surface in the broken composites appears at higher temperatures, which indicates that the toughness of nanosilica-modified GF/pCBT composites is improved. [ABSTRACT FROM AUTHOR]

Repairing delamination damage is critical to guarantee the structural safety of carbon fiber-reinforced thermosetting composites. The popular repair approaches, scarf repair and injection repair, can significantly restore the in-plane mechanical performance. However, the out-of-plane properties become worse due to the sacrifice of fiber continuity in these repairing processes, leading to the materials being susceptible under service loads. Here, we propose a novel in situ delamination repair approach of controllable thermal ablation in damage removal, achieving a high repair efficiency without impairing the fiber continuity in carbon fiber/epoxy panels. The epoxy resin in the delaminated region was eliminated under the carbonization temperature in a few minutes, allowing the carbon fiber frame to retain its structural integrity. The healing agent, refilled in the damaged region, was cured by the Joule heating of designed electrodes for 30 min at 80 °C, yielding the whole repair process to be accomplished within one hour. For the delaminated carbon fiber/epoxy panels with thicknesses from 2.5 to 6.8 mm, the in-plane compression-after-impact strength after repair could recover to 90.5% of the pristine one, and still retain 74.9% after three successive repair cycles of the 6.8 mm-thick sample. The simplicity and cost-saving advantages of this repair method offer great potential for practical applications of prolonging the service life of carbon fiber-reinforced thermosetting composites. [ABSTRACT FROM AUTHOR]

• A finite element interface element is constructed to capture the interface effect. • An anisotropic computational model is developed considering interface effect. • Stress and strength of nanoparticle-reinforced composites are investigated. • The interface effects alter stress concentration performance. Nanoparticle-reinforced metal-based composites (NRMCs) have gained recognition for their remarkable interface effects and their demonstration of superior mechanical properties. To effectively account for interfacial effects and precisely assess the mechanical properties of NRMCs with arbitrarily complex internal structures, our study employs the principle of minimum energy and leverages the Gurtin-Murdoch interface theory to devise a finite element interface element that comprehensively considers the interface effect of NRMCs. Utilizing this novel interface element, we construct diverse NRMCs model and subject them to single-axis tension and compression simulations. Our findings reveal that the developed finite element model accurately captures the internal stress distribution of the NRMCs. Both the particle modulus and interfacial effects exert influence on the Young's modulus of the model. When the particle modulus is small, interfacial effects have a large impact on Young's modulus. Additionally, the effect of interface residual stress on Young's modulus is strongly dependent on the direction of external loading. The developed finite element model offers a scientific approach for accurately predicting the mechanical performance of NRMCs. [ABSTRACT FROM AUTHOR]

Monitoring the curing defects as well as damages that occur in the fabrication and application process is important for ensuring the safety of composite structures. In this paper, a highly sensitive 1‐D line sensor is designed to achieve self‐sensing and diagnosing functionalities in both the fabrication and application of glass fiber reinforced epoxy (GF/epoxy) composites. The sensor consists of multi‐walled carbon nanotube coated glass fiber (MWCNT@GF), which is sensing the damage by the principle of resistance change. Due to the vacuum‐assisted resin infusion process, the MWCNT@GF sensor is embedded into GF/epoxy composite laminates, and hence, it can monitor the resin frontal flow, curing, and especially the flow defects. In the subsequent application, the tensile performance of a GF/epoxy composite joint is evaluated by not only the force‐displacement curve but also the displacement‐dependent resistance change of the sensor. Tensile damage modes are distinguished, which is for the first time to be reported. The MWCNT@GF sensor is mechanically stable and highly sensitive; hence, it can be used to follow the composite performance from fabrication until the end of life. [ABSTRACT FROM AUTHOR]

As a type of environmentally-friendly and low-cost natural material, bamboo fibers exhibit excellent mechanical properties. In this study, a bamboo fiber reinforced polybenzoxazine composite was fabricated by an improved hot-pressing process. The dynamic compressive behaviors of neat benzoxazine and its composite were comparatively studied by an SHPB (split Hopkinson pressure bar) apparatus. SHPB tests showed that the benzoxazine matrix and its composite exhibited significantly positive strain rate sensitivity at nominal strain rates in the range of 0.006–2500/s. During the impact loadings, the progressive deformation and failure of neat benzoxazine and bamboo composite were investigated by capturing real-time images with a high-speed camera. In comparison with neat benzoxazine, the bamboo composite had slightly higher maximum compressive stress under the same strain rates. It is noteworthy that the crashworthiness of the composite was remarkably better than that of neat benzoxazine due to the incorporation of bamboo fibers. For example, the energy absorption of bamboo composite was 105.7% higher than that of neat benzoxazine at a strain rate of 2500/s. The dynamic compressive properties of benzoxazine resin were much better than most of the conventional thermosetting resins. These results could guide the future application of this kind of composites. [ABSTRACT FROM AUTHOR]

This study mainly combines single factor experiment with orthogonal experiment to systematically investigate the effects of particle size, inoculum amount, pH value of the medium, ultrasonication time and species of surfactant on biodesulfurization of the high sulfur coal from Shanxi by using Thiobacillus ferrooxidans, Escherichia coli and Pseudomonas putida. The results revealed that the dominant strain was Pseudomonas putida which attained 58.23% of total sulfur removal during 10 days at the particle size of -125 + 75 μm, pH of 6.0, inoculum amount of 25 mL, ultrasonication time of 60 mins and Tween 80 concentration of 0.1%. Analysis of raw coal and biotreated coal by FTIR spectroscopy and X-ray diffraction indicated a modification of the coal structure after biodesulfurization. The curves of thermogravimetry (TG) for raw coal and biotreated coal also showed that the temperature of the coal pyrolysis significantly reduced, which meant that the thermal stability of the coal after biodesulfurization was lowered than raw coal. And the energy value of coal was not affected in the biodesulfurization process. After treatment with Pseudomonas putida, its calorific value only increased from 6308 cal/g to 6326 cal/g. Liquid products after biodesulfurization were extracted with a series of organic solvents, and each extract was characterized by gas chromatography-mass spectrometry (GC/MS), indicating the presence of sulfur-containing organic compounds in the liquid phase product. Ultimately, following these characterization results, the desulfurization mechanisms of all three bacteria were derived. [ABSTRACT FROM AUTHOR]

Increasing evidence indicates that altered expression of microRNAs (miRNAs) is associated with osteoarthritis (OA) progression. In our study, we demonstrated that miR-377–3p is underexpressed in OA-affected cartilage and IL-1β–treated chondrocytes. Overexpression of miR-377–3p enhanced chondrocyte proliferation and restrained apoptosis and signs of cartilage matrix degradation and of an inflammatory response. Furthermore, ITGA6 was identified as a target gene of miR-377–3p. The latter was found to directly bind to the 3′ untranslated region (3′UTR) of ITGA6 mRNA and downregulate ITGA6. In addition, ITGA6 expression was high in OA-affected tissues and negatively correlated with miR-77–3p expression. Overexpression of ITGA6 reversed the effects of miR-377–3p on IL-1β–caused chondrocyte apoptosis, cartilage matrix degradation, and the inflammatory response. Moreover, bioinformatic analysis and a luciferase assay indicated that miR-377–3p expression is regulated by long noncoding RNA NEAT1, which binds to miR-377–3p and inactivates it. We showed that NEAT1 was highly expressed in OA-affected cartilage, negatively correlated with miR-377–3p levels, and positively correlated with ITGA6 levels. These findings provide information for the development of future treatments of OA, suggesting that miR-377–3p may be a therapeutic target in OA. • MiR-377 expression is low in OA-affected cartilage and IL-1β–treated chondrocytes. • Effects of miR-377–3p on proliferation and apoptosis of IL-1β–treated chondrocytes. • Effects of miR-377–3p on signs of cartilage matrix degradation and of an inflammatory response in IL-1β–treated chondrocytes. • ITGA6 overexpression reverses the negative effect of miR-377–3p on IL-1β–induced chondrocyte apoptosis and signs of the inflammatory response. • NEAT1 promotes ITGA6 expression by sponging miR-377–3p in chondrocytes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Superhydrophobic anti-icing/deicing film prepared by laser etching technique. • Active heating eliminates mechanical interlocking between ice and surface. • Micropillars capture more light than smooth surfaces. Superhydrophobic materials have received wide attention in anti-/deicing field because of their hydrophobicity and anti-icing properties. In this paper, a MXene/PEI (Polyetherimide) superhydrophobic anti-/deicing composite film was prepared by laser etching method. The micropillar etched on the film surface can provide superhydrophobicity and increase the light area. The superhydrophobic film coupled with photothermal MXene possess both anti-icing and active deicing properties. The results show that the freezing time of droplets on the MXene/PEI composite film surface is 7 times longer compared to untreated PEI film. In the photothermal deicing mode, the surface temperature rises rapidly when the surface is activated by near infrared light, reaching an equilibrium temperature of up to 188 °C. The photothermal behavior can completely melt the ice droplets on the surface within 19 s, achieving an efficient and stable deicing effect. This research work will broaden the design and preparation ideas of anti-/deicing film, which has broad application prospects in aerospace and industrial equipment fields. [ABSTRACT FROM AUTHOR]

Wood composites often exhibit weak interaction between urea-formaldehyde (UF) and wood, leading to edge warping and cracks at the bonding interphase. To address this issue, the high-voltage electric field (HVEF) has been effectively employed to enhance the bonding strength of wood composites. This study aims to further investigate the bonding process and the mechanism of bonding enhancement under HVEF treatment by examining the physicochemical characteristics, curing reaction of UF adhesive, and dynamic wetting behavior on the wood tangential section. The chemical reaction and bonding strength at the bonding interphase were also examined. The results revealed that the HVEF treatment increased the polarization extent of the adhesive molecules, resulting in variations in the physical properties of the adhesive. Particularly, a higher enthalpy during the adhesive curing reaction was observed, with an 85% increment observed under the N–P(−) condition. The FTIR spectra showed an increased peak intensity of UF main chemical bonds and a higher extent of chemical interaction between wood and UF functional bonds under HVEF treatment. These findings can be attributed to higher degrees of molecule activation and cross-linking between wood and UF. Furthermore, the HVEF treatment led to a decreased absorption ratio of UF and an increased wet/dry wood bonding strength of the two-layer composite. The absorption ratio of UF exhibited the highest decrement of 36%, while the wet/dry wood bonding strength showed the highest increment of 85%/100% under the N–P(−) condition. This study emphasizes the significant role of higher extents of UF polarization, activation, and cross-linking with wood in enhancing the bonding strength of HVEF-treated wood composites. [ABSTRACT FROM AUTHOR]

In this paper, a new shape memory alloy (SMA) hybrid basalt fibre reinforced polymer (BFRP) composite laminate was fabricated and a new surface modification method with both silane coupling agent KH550 and Al2O3 nanoparticles was conducted to enhance the interface performance. The mechanical performance of BFRP composite laminates with and without SMA fibres and the influence of SMA surface modification were studied in this paper. Different SMA fibre surface treatment methods, including etching with both H2SO4 and NaOH, modification with the silane coupling agent KH550 and new modification method with both KH550 and Al2O3 nanoparticles, were conducted to enhance the bonding between the SMA fibres and polymer matrix. Scanning electron microscopy (SEM) was used to observe the micromorphology of the SMA fibre surfaces exposed to different treatments and the damage morphology of composite laminates. The mechanical performance of the composites was investigated with tensile, three-point bending and low-velocity impact tests to study the influence of embedded SMA fibres and the different surface modifications of the SMA fibres. The results demonstrated that the embedded Ni-Ti SMA fibres can significantly enhance the mechanical performance of BFRP composite laminates. SMA fibres modified with both the silane coupling agent KH550 and Al2O3 nanoparticles illustrate the best mechanical performance among all samples. [ABSTRACT FROM AUTHOR]

Ice accumulation often threatens the safety of human life and property. How to effectively solve the problem of solid surface icing has been the research work of many researchers. However, how to prepare superhydrophobic and anti-icing film with multi-strategy collaborative deicing is still facing great challenges. In this paper, a design strategy of photothermal and electrothermal superhydrophobic nanocomposite film based on polyetherimide (PEI) was proposed. Multi-walled carbon nanotubes (MWCNT) were dispersed in PEI matrix by solution blending method, and a lotus leaf like rectangular micropillar array was constructed on the surface of the film by laser etching technology. Then, the surface was fluorinated to further reduce the surface energy. Finally, a kind of MWCNT/PEI nanocomposite film with passive anti-icing and active deicing with photothermal and electrothermal collaboration was successfully prepared. The freezing time of droplets on MWCNT/PEI nanocomposite film is about 6.7 times longer than that of pure PEI film. This film exhibits excellent superhydrophobicity (CA = 156.6°), while also having excellent photothermal and electrothermal conversion properties. In addition, we also conducted various tests on MWCNT/PEI nanocomposite film to verify its reliability in the actual application environment. The MWCNT/PEI nanocomposite film with the function of anti-icing and photothermal and electrothermal active deicing is expected to solve the problem of solid surface icing in daily life, and also provides a new idea for the development of a new generation of anti-icing/deicing film. [Display omitted] • Superhydrophobic anti-icing/deicing film prepared by laser etching technique. • Dual strategy synergistic active deicing. • Micropillar can capture more light, increase the photothermal conversion efficiency. [ABSTRACT FROM AUTHOR]

Shape memory polymer (SMP) surfaces can achieve wettability transition by controlling microstructure have attracted great attention. However, attempts at achieving in situ reversible switching capability remain largely challenging. This paper aims to elaborate on the preparation of a shape memory superhydrophobic surface with switchable wettability and electrothermal performance. The surface microstructure array is regulated by the shape memory effect based on the electrothermal response, and the reversible switching of the wetting state is realized under the action of voltage and external force. Different microstructural morphologies exhibit different solid-liquid contact states, as well as large/small contact angles and low/high adhesion. In addition, the rapid thermal response, excellent thermal conductivity, and satisfactory durability provide the possibility for anti-icing/deicing. The structure can prevent droplet aggregation, greatly delay the nucleation of droplet crystallization, and remove ice by Joule heat. In short, this work successfully realized the in-situ control of surface wettability which also provided a significant application potential in droplet manipulation, droplet writing, anti-icing/deicing, and other fields. [Display omitted] • In-situ electrothermal response through composite structure. • The solid-liquid contact forms under different micropillar states were observed. • The structure has excellent electrothermal performance and anti-icing ability. • Regulates surface wettability for droplet manipulation, writing and screening. [ABSTRACT FROM AUTHOR]

Objective Dysregulation of miRNA is always associated with cancer development and progression. Aberrant expression of miR-217 has been found in some types of cancer. However, its expression and function in osteosarcoma remain unclear. The aim of this study was to explore the effects of miR-217 in osteosarcoma tumorigenesis and development. Methods The expression level of miR-217 was quantified by real-time RT-PCR in human osteosarcoma cell lines and tissues. MTT, flow cytometric, transwell invasion and migration assays, and tumorigenicity in vivo were adopted to observe the effects of miR-217 on MG-63 cell phenotypes. Results MiR-217 was significantly downregulated in osteosarcoma cell lines and clinical specimens. Decreased miR-217 expression was significantly associated with large tumor size, positive distant metastasis, and advanced clinical stage. Low miR-217 expression in osteosarcoma was an independent predictor of poor survival. Overexpression of miR-217 can inhibit the proliferation, invasion, migration and promoted apoptosis of MG-63 cells in vitro and in vivo . Conclusions These findings indicate that miR-217 may act as a tumor suppressor in osteosarcoma and would serve as a novel therapeutic agent for miRNA-based therapy. [ABSTRACT FROM AUTHOR]