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• Utilizing a pre-cracked beam bending test, the energy release rate and J-integral fracture toughness of LPSHAC were measured. • The surface strain field was analysed using digital image correlation (DIC) techniques, the cracking characteristics after fracture were also quantitatively investigated. • Proposing the aggregate fracture area ratio (D a), aggregate mortar boundary fracture area ratio (D am), and mortar fracture area ratio (D m) as novel metrics to reflect LPSHAC's fracture characteristics at different temperatures. This study investigates the fracture properties of large-particle size hydraulic asphalt concrete (LPSHAC) at various temperatures using pre-cracked trabecular bending tests and digital image correlation (DIC). Results show that temperature significantly affects LPSHAC's fracture properties, with the energy release rate and J -integral fracture toughness increasing initially and then decreasing as temperature rises. Horizontal strain better characterizes damage progression at higher temperatures. Crack curvature coefficients at 0 °C and 20 °C increased by 8.2 % and 30.1 % compared to that at −20 °C, while the aggregate fracture area ratio rose as the temperature decreased from 20 °C to −20 °C. [ABSTRACT FROM AUTHOR]

Offshore wind turbine (OWT) upsizing has become an inevitable trend. Compared with small OWTs, large OWT rotors exert greater horizontal loads and bending moments on the tower. These factors make a large OWT tower more prone to geometric nonlinear deformations, which can affect the normal operation of a wind turbine and even lead to damage to the wind turbine tower. Therefore, monitoring the deformation of large OWT towers is necessary. Shape sensing is a technique that uses surface strains to reconstruct deformed shapes. Currently, there is a lack of effective methods for geometric nonlinearity deformation shape sensing. In addition, the tower of OWT is a variable cross-section structure. The influence of varying cross-sections further increases the difficulty of developing a large deformation reconstruction algorithm. To solve this problem, this paper proposes a new method called rotation angle approximation (RAA). This method establishes a least-squares error functional using analytic curvature and section curvature. The rotation angles of the tower axis are obtained via this function. The deformed shape is then predicted via the boundary conditions and the rotation angles along the tower axis. Numerical simulations demonstrated this method can accurately predict the large deformations of a tower under different load conditions. • Proposed a new large deformation shape sensing method for beams with variable cross-section. • The deformed shapes can be predicted only using final measured strain. • Accurate deformation predictions can be achieved with fewer elements. [ABSTRACT FROM AUTHOR]

The article "Peeking under the surface with multilayer strain in cardiac MRI" published in Pediatric Radiology discusses the structure of the myocardium and the use of multilayer strain assessment to describe myocardial deformation. The study focuses on pediatric patients with multisystem inflammatory syndrome in children (MIS-C) and compares their strain measurements to matched controls. The findings suggest that patients with MIS-C have impaired apical radial strain and layer-specific strain at the apical level, indicating potential localized disease or delayed recovery in the apical region. The article highlights the importance of advanced cardiac MRI techniques in understanding disease processes like MIS-C and emphasizes the need for detailed prognostic information to improve patient outcomes. [Extracted from the article]

When testing the mechanical properties of a tailor welded blank (TWB) under uniaxial tension, the localized bending moment generated by eccentric loading, due to the change in thickness between the welded sheets, causes the experimentally measured stress-strain behavior to not match the actual stress-strain behavior. In this paper, a new method to calibrate the tensile stress-strain behavior in the heat affected zone (HAZ) of a TWB with different thicknesses is proposed based on indentation testing and tensile test with multi-camera digital image correlation (DIC). The nominal stress-strain curve is calculated for calibration purposes. The nominal strain is obtained by performing multiple linear regression analysis on the front and back surface strains of the HAZ provided by the multi-camera DIC system. Experiments were conducted using this method on a TWB of the same material (DP1180) and different thicknesses (1 mm and 1.4 mm). The validation of the corrected stress-strain curves demonstrated the reliability and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

CoCrMo has been used as an implant material for a long time due to its excellent combination of strength, corrosion resistance and biocompatibility. The formation of a thin passive oxide film on the surface of the material plays a crucial role in its performance. This passive film can be ruptured during contact between two surfaces, but usually reforms in short timescales. However, the reformation of the film depends on the availability of oxygen in the surrounding fluid. The oxygen level in human tissue, cartilage and synovial fluid, around which the implant is situated, is much lower than that in laboratory testing under open-air conditions. Moreover, the local oxygen concentration and pH values in the body vary from patient to patient, depending on the patient's health condition and other factors, which leads to variation in the corrosion resistance of metallic implants. Therefore, an implant that performs well at one time may still experience an undesirable level of corrosion at another. Thus, evaluation of the tribocorrosion of implant materials carried out in open-air conditions does not reflect the actual process the implants undergo once in the body, particularly if there is irritation due to injury or surgery. In this study, we investigate the tribocorrosion behaviour of CoCrMo in bioactive solutions under fully aerobic to anaerobic conditions with varying loads/contact pressures. The anaerobic condition leads to a reduction in wear rate and a reduction in the extent of tribofilm formation but does not have an appreciable effect on friction. The mechanisms are discussed in detail. • Anaerobic conditions lead to lower wear rates in the sliding of CoCrMo alloys lubricated by bovine serum solution. • The presence of a surface oxide in open-air sliding leads to greater surface strain than under anaerobic conditions. • Anaerobic conditions led to greater dissolution of Mo into the lubricant than in open-air conditions. • In open-air the wear debris was mainly a Cr based oxide; in anaerobic conditions debris was a complicated Cr rich structure. [ABSTRACT FROM AUTHOR]

Composite materials have been widely used as critical components in aerospace applications due to their excellent performance characteristics. The real-time accurate identification and quantification of various types of damage within composite material structures pose a significant challenge. This study introduces an innovative damage detection method based on strain fields, which centrally employs deep learning techniques. Utilizing the Res-Mask R–CNN, this study accurately detects and categorizes various forms of damage within composite laminates, including open holes, subsurface holes, and delamination. Moreover, this method also enables precise localization and quantification of damaged areas. A series of experiments and simulations have validated the accuracy and robustness of the network model. Damage inversion experiments demonstrate that the area error of the damaged regions has been reduced to 7.4 %, and the positional error does not exceed 3.31 mm. In simulated scenarios, the shape context distance for complex damage contours does not exceed 0.21, indicating that the critical geometric features of the damage have been successfully preserved. This study provides an effective new approach for damage detection and real-time structural health monitoring of composite laminates. [Display omitted] [ABSTRACT FROM AUTHOR]

Atrial strain and motion play important roles in evaluation of stroke risks for patients with atrial fibrillation. While cardiac computed tomographic angiography (CTA) provides detailed left atrial morphology with unparallel image resolution, finding a suitable strain measurement method for CTA remains a considerable challenge. In this paper, for the first time, we introduced a mesh regularized image block matching method to estimate 3D left atrial (LA) surface strain with 4D CTA. A series of performance tests with ex-vivo phantom and in-vivo 4D-CTA data were deployed. In conclusion, our proposed method could provide reliable LA motion and strain data within limited time. [ABSTRACT FROM AUTHOR]

The European Organization for Nuclear Research (CERN) is one of the largest nuclear research centres in the world, operating the most powerful particle accelerator housed in a massive 80 km-long underground tunnel network. Over the decades, regular site inspection has observed the ongoing development of structural defects, such as widened cracks, water infiltration and misalignment of the particle accelerator beamline caused by differential tunnel floor settlements. Such ongoing tunnel deterioration necessitates long-term field monitoring and assessment of the continuous deformation behaviour of the tunnel lining. Recently, distributed fibre optic sensing (DFOS) has emerged as a promising tool for monitoring civil structures by providing spatially continuous strain measurements using fibre optic cables. Conventionally, a fibre optic cable can be continuously bonded onto a structure with a flat surface for continuous strain measurement (e.g., pile foundations, retaining walls). Nevertheless, to monitor tunnel circumferential movement, fibre optic cables usually can only be deployed at some discrete fixing points around a curved tunnel surface. The raw DFOS data obtained by this fixing-point method cannot be directly processed into continuous strain measurements due to the discrete nature of the installation. This poses a challenge for accurately analysing tunnel structural performance. To address the limitations of the fixing-point method, this paper presents an optimized data processing method for analysing DFOS strain measurements of curved circumferential tunnel behaviour at the CERN tunnel. The proposed method enables the determination of the actual stepwise strain profile between fixing points and its conversion into tunnel convergence by integrating along the path. The converted DFOS tunnel displacements offer a more realistic and intuitive representation of the tunnel deformation mode than the DFOS strain profile alone. Additionally, the results of tunnel displacement demonstrate agreement with convergence measurements obtained by the conventional total station method, indicating the enhanced capability of DFOS for existing tunnel monitoring and assessment. The DFOS method has the potential to provide highly accurate deformation measurements, with a much higher resolution than the typical measurement accuracy, for example, by total stations. [ABSTRACT FROM AUTHOR]

This study investigates the micro-mechanical response of asphalt microstructure under tensile and compressive loads using atomic force microscopy (AFM) and digital image processing (DIP). AFM captured images of asphalt surface morphology, and DIP extracted geometric information on microstructures such as bee structures, peri phase, and interstitial structures. Five finite element models were created in ABAQUS to simulate their load-bearing capacities and stress-strain distributions under 1 % and 5 % tensile and compressive strains. The results showed minimal differences in load-bearing capacities among the five models under identical strain loads. However, compressive load-bearing capacity was significantly higher than tensile load, with the asymmetry becoming more pronounced as the load increased. Under 1 % compressive strain, the external load was about 3 % higher than under tensile strain, increasing to 36 % higher under 5 % strain. The bee structure exhibited the smallest stress distribution, while the interstitial structure showed the largest. The average maximum stress in the interstitial structure was 1.2 times that of the bee structure, with stress concentration observed at the interface between the peri phase and interstitial structure. The interstitial structure experienced the smallest strain distribution, while the bee structure endured the highest tensile or compressive strain, with the average maximum strain of the bee structure being approximately 1.25 times that of the interstitial structure. Under compressive loads, the maximum stress and strain on the asphalt surface exceeded those under tensile loads, with the difference averaging around 10 % higher. As the proportion of the peri phase increased, stress and strain distribution became more uniform, alleviating stress concentration phenomena. This study provides a potential method for analyzing the mechanical response of asphalt microstructure. The results deepen our understanding of the complex relationship between asphalt microstructure and its micro-mechanical response. Additionally, they suggest possible directions for improving asphalt performance through microstructure adjustment. • AFM is an effective means of obtaining microstructural images of asphalt. • Finite element modeling of asphalt microstructure based on AFM images. • Micromechanical response of different asphalt microstructures under tensile and compressive loading. [ABSTRACT FROM AUTHOR]

• We provide a high-resolution geodetic strain rate model for the central-eastern ATF. • The strike-slip rate on the ATF decreases gradually between ∼90.5°E and ∼94°E. • The shear strain on the ATF terminates in a horsetail structure at ∼95°E. • Fault planes of the ATF are nearly vertical, with strike changes along the bends. • Uplift occurs around restraining bends, being higher at their inside corners. Investigating the present-day pattern of strain accumulation along the Altyn Tagh fault (ATF) in northwestern Tibet is critical for our broader understanding of deformation around large active strike-slip faults and the associated seismic hazards. Previous geodetic and geological studies show an eastward decrease of slip rate along the central-eastern ATF, but the spatial variation of the slip rates and the mechanism causing such variation are uncertain. Additionally, interseismic deformation around the restraining bends along the ATF and its pattern of termination towards its eastern end are also unclear. Here we derive surface velocities and strain rates around the central-eastern ATF system using Sentinel-1 and GNSS velocities. We estimate fault parameters including slip rate and locking depth for the ATF and other related active faults indicated by our strain rate maps using a Bayesian inversion approach. Our results show shear strain is mainly concentrated on the ATF between 86°E and 95°E. The strike-slip rate of the ATF remains constant at ∼8 mm/yr between 86°E and 90.5°E, before decreasing gradually to ∼4.5 mm/yr between 90.5°E and 94°E due to the crustal shortening across the Qaidam basin. Shear strain on the ATF is terminated in a horsetail structure at 95°E, where the strain is split into the motion along the Danghe Nanshan fault, Yema River – Daxue Shan fault and north Altyn Tagh fault. Our strain rate fields show fault planes are nearly vertical beneath the ATF, and there are obvious changes in the strike of the deep shearing part of the fault beneath the Akato Tagh bend and Aksay bend. The Akato Tagh and Pingding Shan bends feature higher peak strain rates and narrower width of the interseismic straining zone at the surface, compared to straight sections like the Xorkoli segment. We observe long-wavelength uplift signals in the East Kunlun Shan range, Altun Shan range, Qaidam basin, restraining bends along the ATF and the Qilian Shan – Nan Shan thrust belt. We consider uplift of the latter is controlled by the thrust motion of the active faults within it, as almost all shortening within it occurs across the fault zones. Uplift around restraining bends along the ATF exhibits a larger rate at their inside corners, which is evidence of potential vertical-axis rotation within the bends. Our results provide a noteworthy example of how the strain is accumulated and terminated on a large-scale intra-plate strike-slip fault. [ABSTRACT FROM AUTHOR]

The work studied the damage and fracture characteristics of granite samples with circular holes and parallel fractures of different lengths under uniaxial compression conditions. Acoustic emission (AE) monitoring and digital image correlation (DIC) were used to analyze the dynamic changes of AE parameters, the evolution characteristics of the deformation field on the sample surface, and the correlation between the fractal dimension and the fracture geometry parameters. A computational model was proposed for evaluating the intensity factor of the fracture tip in a double-fracture structure with holes. The interaction between the fractures was considered to reveal the complex law of the intensity factor and the fracturing angle with the fracture geometry. The changes in AE parameters and fractal dimension indicated the influence of fracture extension on the damage mode of samples. Besides, the fracture length affected the micro-fracture behavior. The surface displacement and strain characteristics of samples revealed the modulation effect of the fracture length on the failure mode. The inclination angle, length, holes, and size of the fractures' friction coefficient significantly affected the evolution of the intensity factor, which in turn regulated the changes in the fracture angle. The work offers a novel quantitative analytical approach and a theoretical framework for comprehending the damage and failure mechanisms of porous and fractured rocks through extensive experimentation and theoretical analysis. It holds significant practical relevance in geological engineering, mining, and tunnel construction. [ABSTRACT FROM AUTHOR]

The article proposes a method to calculate the main direction strain inside the carbon fiber laminate based on the measured strain on the surface. The method is to paste strain gauges on the surface of the laminate, and the main direction strain inside the laminate is deduced through the selection of strain gauges, the determination of the paste method, the acquisition and processing of data, and the combination of the relevant theories of mechanics of materials and mechanics of composite materials. This method effectively solves the difficult problem of strain measurement inside carbon fiber laminates. The article validates the method with different layers of the laminate as test objects. The accuracy of the strain measurement of the surface layer and the validity of the calculation of the main directional strain of the internal layers based on the measured strain are verified by means of tests and finite element software calculations. [ABSTRACT FROM AUTHOR]

• The effect of high shearing speed on the performance of electromagnetic self-pierce riveting-bonded joint with CFRP/Al joint was investigated. • The strain analysis of the joints under different load speed was studied by digital image correlation (DIC) method. • The failure mechanism of joints under static and high speed load was revealed. The mechanical performance of dissimilar material riveted joints is important for passenger safety during a crash situation. Hence, in this paper, the mechanical properties of CFRP-aluminum electromagnetic self-pierce riveting-bonded (E-SPR-bonded) joints under quasi-static and dynamic loading was investigated. First, the hybrid joints were manufactured under five discharge energies to explore the best process parameter, then, the effect of shearing speed on the mechanical properties were studied. Digital image correlation (DIC) method was carried out to further understand the surface strain distribution. Results indicated that the evolution of shear tests could be divided into two stages, including two peak loads, named peak A and peak B, respectively. The hybrid joint at 7.7 kJ had the best peak load during static load. Under the dynamic loading condition, the peak load increased with ascending load speed, especially the peak B, under 4, 8 and 12 m/s, were 189.0 %, 205.5 %, and 215 % higher than that of 2 mm/min, respectively. The hardening effect of sheets was increased under high shear speeds, which dominated the fracture behaviors of the bonding layer. The hybrid joints failure behavior was the CFRP fracture, and the rivet remained in the aluminum sheets. The results could provide theoretical guidance for the structural design of automobiles and promote its engineering application. [ABSTRACT FROM AUTHOR]

The often-assumed measurement reciprocity between scanning laser detection and scanning laser excitation is disproved by a simple experiment. Nevertheless, a deeper study based on the reciprocity relation reveals correct reciprocal measurement set-ups for both the probe-excitation/laser-detection and the laser-excitation/probe-detection case. Similarly, the all-laser measurement, that is thermoelastic laser excitation with laser vibrometer detection, is not in general reciprocal with respect to the exchange of excitation and detection positions. Again, a substitute for the laser doppler vibrometer out-of-plane displacement measurement was found which ensures measurement reciprocity together with laser excitation. The apparent confusion in literature about strict validity/non-validity of measurement reciprocity is mitigated by classifying the measurement situations systematically. [Display omitted] • The strict reciprocity between scanning laser doppler vibrometry (SLDV) and scanning laser generation method (SLGM) is disproved. • There is also no reciprocity for swapped laser excitation and laser detection positions in full laser ultrasound (FLUS). • New measurement reciprocities are theoretically derived and partly demonstrated by numerical simulations. • The derived measurement reciprocities involve alternative surface measurement values. Some of them rely on surface strain measurements. [ABSTRACT FROM AUTHOR]

The complexity of the interaction between the workpiece and abrasives, the characterisation difficulty of the strain-rate effect, and the analytical difficulty of brittle-ductile coexistence removal pose significant challenges in surface micro-morphology modelling of brittle-solid grinding. To overcome these bottlenecks, a theoretical model of the normal scratching force driven by the strain-rate effect was developed to verify the strain-rate sensitivity coefficients of gallium nitride (GaN) crystals. Impact scratching tests with a single grit further emphasised that the brittle-to-ductile transition and subsurface damage behaviour of GaN crystals exhibited a distinct strain-rate dependence. Subsequently, a theoretical model of the surface micro-morphology involved in the grinding of GaN crystals was developed by comprehensively considering the strain rate, abrasive coupling effect, time evolution, abrasive randomness, and elastic-to-plastic and brittle-to-ductile transition depths. The simulated results of the model agreed well with the experimental results, with an average error of <10 %. The model indicated that the ground surface micro-morphology and roughness were insensitive to variations in the grinding depth. Under the allowable conditions of the grinder stiffness and dynamic balance, appropriately increasing the wheel speed and grinding depth, decreasing the feed speed, and refining the abrasive size could effectively improve the proportion of ductile removal during the grinding of brittle solids. The results not only enhance the understanding of the abrasive coupling effect on surface micro-morphological evolution, material removal, and damage accumulation, but also provide theoretical guidance for the parameter optimisation involved in the grinding of brittle solids. [Display omitted] • A novel model of ground surface micro-morphology emphasises the significance of strain rate and abrasive coupling effects. • Time evolution, abrasive randomness, elastic-to-plastic and brittle-to-ductile transitions improve model accuracy. • Appropriately increasing grinding speed, decreasing feed speed and and refining abrasive size promote plastic removal. • Ground surface micro-morphology and roughness exhibit insensitivity to variation of grinding depth. • A novel model of normal scratching force driven by strain rate is developed. [ABSTRACT FROM AUTHOR]

Citrobacter sp. XT1-2-2, a functional microorganism with potential utilization, has the ability to immobilize soil cadmium. In this study, the regulatory gene cys H, as a rate-limiting enzyme in the sulfur metabolic pathway, was selected for functional analysis affecting cadmium immobilization in soil. To verify the effect of APS reductase on CdS formation, the ΔAPS and ΔAPS-com strains were constructed by conjugation transfer. Through TEM analysis, it was found that the adsorption of Cd2+ was affected by the absence of APS reductase in XT1-2-2 strain. The difference analysis of biofilm formation indicated that APS reductase was necessary for cell aggregation and biofilm formation. The p-XRD, XPS and FT-IR analysis revealed that APS reductase played an important role in the cadmium immobilization process of XT1-2-2 strain and promoting the formation of CdS. According to the pot experiments, the cadmium concentration of roots, culms, leaves and grains inoculated with ΔAPS strain was significantly higher than that of wild-type and ΔAPS-com strains, and the cadmium removal ability of ΔAPS strain was significantly lower than that of wild-type strain. The study provided insights into the exploration of new bacterial assisted technique for the remediation and safe production of rice in cadmium-contaminated paddy soils. [Display omitted] • Gene cys H was the control switch for the production of CdS. • Gene cys H was involved in the sulfate metabolism pathway. • Gene cys H affected the biofilm production. • Cd was able to accumulate inside and on the surface of strain. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salts (QAS) commonly occur as active substances in disinfectants. QAS have the important property of coating abiotic surfaces, which prevents adhesion of microorganisms, thus inhibiting biofilm formation. In this study, a group of nine monomeric QAS, differing in the structure and length of the aliphatic chain (C12, C14, C16) and the counterion (methylcarbonate, acetate, bromide), were investigated. The study included an analysis of their action against planktonic forms as well as bacterial biofilms. The compounds were tested for their anti-adhesion properties on stainless steel, polystyrene, silicone and glass surfaces. Moreover, mutagenicity analysis and evaluation of hemolytic properties were performed. It was found that compounds with 16-carbon hydrophobic chains were the most promising against both planktonic forms and biofilms. Tested surfactants (C12, C14, C16) showed anti-adhesion activity but it was dependent on the type of the surface and strain used. The tested compounds at MIC concentrations did not cause hemolysis of sheep blood cells. The type of counterion was not as significant for the activity of the compound as the length of the hydrophobic aliphatic chain. [ABSTRACT FROM AUTHOR]

Laminated plates are often modeled with infinite dimensions in terms of the so-called Whitney–Nuismer (WN) stress criteria, which form a theoretical basis for predicting the residual properties of open-hole structures. Based upon the WN stress criteria, this study derived a new formulation involving finite width; the effects of notch shape and size on the applicability of new formulae and the tensile properties of carbon-fiber-reinforced plastic (CFRP) laminates were investigated via experimental and theoretical analyses. The specimens were prepared by using laminates reinforced by plain woven carbon fiber fabrics and machined with or without an open circular hole or a straight notch. Standard tensile tests were performed and measured using the digital image correlation (DIC) technique, aiming to characterize the full-field surface strain. Continuum damage mechanics (CDMs)-based finite element models were developed to predict the stress concentration factors and failure processes of notched specimens. The characteristic distances in the stress criterion models were calibrated using the experimental results of un-notched and notched specimens, such that the failure of carbon fiber laminates with or without straight notches could be analytically predicted. The experimental results demonstrated well the effectiveness of the present formulations. The new formula provides an effective approach to implementing a finite-width stress criterion for evaluating the tensile properties of notched fiber-reinforced laminates. In addition, the notch size has a great effect on strength prediction while the fiber direction has a great influence on the fracture mode. [ABSTRACT FROM AUTHOR]

A facile and general strategy for the preparation of highly dispersed PtCo/C catalysts with a Pt-enriched surface is reported. The thermal treatment of the PtCo/C catalyst changes the structure orientation from disordered to ordered phase. Ordered PtCo/C intermetallic catalyst exhibits significantly enhanced electrocatalytic activity and durability toward oxygen reduction reaction (ORR) compared with its disordered counterpart and commercially available PtCo/C, with a mass activity and specific activity of 0.68 A mg Pt −1@0.90 V and 1.15 mA cm−2, respectively. In addition, the mass activity only decreased by 25.1% after 30,000 potential cycles from 0.60 to 1.00 V at a scan rate of 100 mV s−1. Therefore, the improved ORR activity and stability can be ascribed to the atomic ordered surface arrangement and reasonable surface compress strain originated from Pt-enriched surface. • A widely applicable strategy to synthesize ordered intermetallic PtCo/C. • Ordered surface arrangement and reasonable surface compress strain contributed to high activity. • Ordered PtCo/C shows ORR mass activity of 0.68 A mg−1 Pt @ 0.90 V. • Ordered PtCo/C exhibits a mass activity loss of only 25.1% after ADT. [ABSTRACT FROM AUTHOR]

Distributed acoustic sensing (DAS) strain rate and particle velocity can be compared through approximate scaling with medium velocity. We instead performed a direct comparison between array derived dynamic strain (ADDS) rate and DAS strain rate for six frequency bands. The PoroTomo project at Brady's Hot Springs, Nevada, deployed a 240‐geophone 3C array co‐located with fiber‐optic DAS system and 8.7 km of buried cable. We selected subsets of the geophone array to create four smaller arrays and computed ADDS. The horizontal components of the ADDS were rotated into the direction of the fiber‐optic cable and then compared with the observed DAS strain rates. From three example regional earthquakes of local magnitudes 2.9, 4.1, and 4.3, the ADDS are found to be coherent with DAS for frequencies ≤1 Hz. For frequencies >1‐Hz, this correlation decays quickly. Small differences between linear and areal dynamic strains at 1‐Hz suggest poor signal‐to‐noise or localized strain that is perturbed by shallow heterogeneities compare to the average strain propagating across the geophone array. The implication is that around 1‐Hz, straight fiber DAS is measuring axial strain along the fiber and can provide good approximations to translational particle motions. However, above 1‐Hz, DAS becomes more sensitive to shallow velocity gradients that can be beneficial for geophysical imaging yet becomes a limitation for traditional seismic analysis methods depending on absolute amplitude and phase from translational particle motions. Plain Language Summary: Seismological measurements including ground displacement are based on the motion at a point in 3‐dimensional space through time. Fiber‐optic distributed acoustic sensing (DAS) instead measures strain, a component of deformation that is the difference in motion between two points in space through time. We know that strain is much more sensitive to shallow Earth structure beneath the receiver and surrounding topography than traditionally measured particle motions. We examine the variability of surface strain along a line versus the average strain over an area and also how these variabilities change over both frequency and spatially across the extent of an array. We show that the strain over an area versus axial strain measured from DAS varies in amplitude and phase for several frequency bands. These results have implications on how methods developed in seismology based on traditional seismometers can be used with fiber‐optic DAS data analysis. Key Points: Array derived dynamic strains (ADDSs) are in agreement (correlation coefficients ∼0.9) with distributed acoustic sensing (DAS) strain rate for f ≤ 1 HzFor f > 1 Hz, the correlation between DAS and array derived strains decays quicklyThe root‐mean‐square amplitude ratios between ADDS rate and DAS strain rate is ∼1 below f ∼ 2 Hz but increases with frequency [ABSTRACT FROM AUTHOR]

The exploitation of the earth‐abundant catalysts with high reactive activity for hydrogen evolution reaction (HER) remains a grand challenge, which is strongly related with their superficial electronic structure. Herein, the Co‐layered LaCoSi material is proposed to disclose the electronic state coupling between structural strain and defect distribution, where the bonding interaction between reactants and catalysts can be affected by the electronic reconfiguration at reactive sites. Comprehensive first‐principle calculations disclose that the catalytic activity of Co site can be obviously enhanced by tensile strain, and the antibonding interaction between Co and adsorbed hydrogen is also enforced. However, the introduced Si defect can make the neighboring Si atoms gain more 3d electrons from Co site, leading to a compressive‐strain‐response HER performance. The analysis about electronic structure demonstrates that the coupled electronic states play a critical role in enhancing HER performance. This work provides a new insight into designing new‐type catalysts by considering the synergistic effect of surface strain and defect engineering. [ABSTRACT FROM AUTHOR]

The strain occurs spontaneously at the heterogeneous interfaces of virtually all crystalline materials. Consequently, the analysis across multiple interfaces requires a complementary characterization scheme with a resolution that fits the deformation scale. By implementing two-photon confocal laser scanning nanoscopy with an axial resolution of 10 nm, we extract the surface strain from the photoluminescence (PL) spectra, epitomized by a 2-fold enhancement at the tapered tips in comparison to the substrate of ZnO nanorods. We firstly traced the well-established contribution from quantum confinement (QC) to PL shift in three geometrically classified regions: (I) a strongly tapered region where the diameter increases from 3 to 20 nm; (II) a weakly tapered region with a gradually increasing diameter from 20 to 58 nm; (III) round cylindrical region interfacing the sapphire substrate. The measured PL shift influenced by the deformation is significantly stronger than the attained QC effect. Particularly, surface strain at the strongly tapered region turned out to drastically increase the PL shift which matches well with the analysis based on the surface to volume ratio incorporating mechanical parameters such as the compliance tensor component, strain dislocation constant, and surface stress. The surface strain increased at a lower temperature, further disclosing its inherent dependence on the thermal expansion coefficients in clear contrast to the temperature-invariant characteristics of QC. [ABSTRACT FROM AUTHOR]

The dynamic fracture process of rock materials is of importance for several industrial applications, such as drilling for geothermal installation. Numerical simulation can aid in increasing the understanding about rock fracture; however, it requires precise knowledge about the dynamical mechanical properties alongside information about the initiation and propagation of cracks in the material. This work covers the detailed dynamic mechanical characterisation of two rock materials—Kuru grey granite and Kuru black diorite—using a Split-Hopkinson Pressure Bar complemented with high-speed imaging. The rock materials were characterised using the Brazilian disc and uniaxial compression tests. From the high-speed images, the instant of fracture initiation was estimated for both tests, and a Digital Image Correlation analysis was conducted for the Brazilian disc test. The nearly constant tensile strain in the centre was obtained by selecting a rectangular sensing region, sufficiently large to avoid complicated local strain distributions appearing between grains and at voids. With a significantly high camera frame rate of 671,000 fps, the indirect tensile strain and strain rates on the surface of the disc could be evaluated. Furthermore, the overloading effect in the Brazilian disc test is evaluated using a novel methodology consisting of high-speed images and Digital Image Correlation analysis. From this, the overloading effects were found to be 30 and 23%. The high-speed images of the compression tests indicated fracture initiation at 93 to 95% of the peak dynamic strength for granite and diorite, respectively. However, fracture initiation most likely occurred before this in a non-observed part of the sample. It is concluded that the indirect tensile strain obtained by selecting a proper size of the sensing region combined with the high temporal resolution result in a reliable estimate of crack formation and subsequent propagation. [ABSTRACT FROM AUTHOR]

The individual coupling processes of two-phase materials are controlled to some extent by damage theory. However, the existing theory is not sufficient to explain the effect of pore pressure on mortar materials under freeze-thaw action. In order to predict the resistance of saturated mortars during rapid cooling and to describe the physical behavior of the pore structure, the authors derived in detail the governing equations of saturated mortars during freezing in the framework of the pore elasticity theory and analyzed the sensitivity of physical parameters to the influence of temperature stresses by means of stress-strain calculations. In addition, the effects of phase change and latent heat of freezing on the local thermodynamic equilibrium are considered, and a mathematical model is established for quantitatively simulating the temperature distribution of the specimen. This model is reformulated and extended in the current work to intuitively reveal the effect of concrete dimensions on the temperature hysteresis effect. The results of the numerical model calculations show that during the freezing process, for the specimen with dimensions of 50 mm × 50 mm × 50 mm and a water-cement ratio of 0.6, the maximum temperature difference from center to surface is 10 °C, the maximum vertical strain on the surface is 4.27 × 10−4, and the maximum pore water pressure at the center of the specimen is 76 MPa. The model calculation results present a similar pattern to the physical interpretation and reference results, thus effectively evaluating the freezing damage process of saturated mortar. [ABSTRACT FROM AUTHOR]

The present work proposes a systematic procedure for the evaluation of high temperatures deformation and formability of α + β brass undergoing the stretch forming process. Firstly, flow stress has been predicted by the most popular Johnson-Cook (JC) uniaxial constitutive model at a wide range of temperatures (773 K, 873 K and 973 K) and strain rates (0.001 s−1, 0.01 s−1 and 0.1 s−1). For yielding performance evaluation, FLC integrated with Barlat'89 function has been substituted by the traditional Hill'48 function. The necking curves have been constructed with the uniaxial constitutive model and eminent the Barlat'89 yield criterion. The fracture locus is mathematically derived from the forming limit curves (FLCs). These FLC have been experimentally deceived through a series of standard Nakazima tests. Further, the predicted FLCs by Marciniak–Kuczynski (M–K) model have been compared for different loading conditions. The predicted FLCs with Barlat'89 yield function performed outstanding compared to Hill'48 function. Furthermore, formality studies by means of forming limit diagram, limit dome height and surface strain distribution have been analysed. [ABSTRACT FROM AUTHOR]

The discovery of two-dimensional (2D) van der Waals (vdW) materials often provides interesting playgrounds to explore novel phenomena. One of the missing components in 2D vdW materials is the intrinsic heavy-fermion systems, which can provide an additional degree of freedom to study quantum critical point (QCP), unconventional superconductivity, and emergent phenomena in vdW heterostructures. Here, we investigate 2D vdW heavy-fermion candidates through the database of experimentally known compounds based on dynamical mean-field theory calculation combined with density functional theory (DFT+DMFT). We have found that the Kondo resonance state of CeSiI does not change upon exfoliation and can be easily controlled by strain and surface doping. Our result indicates that CeSiI is an ideal 2D vdW heavy-fermion material and the quantum critical point can be identified by external perturbations. [ABSTRACT FROM AUTHOR]

The motion information of blades is a key reflection of the operation state of an entire wind turbine unit. However, the special structure and operation characteristics of rotating blades have become critical obstacles for existing contact vibration monitoring technologies. Digital image correlation performs powerfully in non-contact, full-field measurements, and has increasingly become a popular method for solving the problem of rotating blade monitoring. Aiming at the problem of large-scale rotation matching for blades, this paper proposes a modified speeded-up robust features (SURF)-enhanced digital image correlation algorithm to extract the full-field deformation of blades. Combining an angle compensation (AC) strategy, the AC-SURF algorithm is developed to estimate the rotation angle. Then, an iterative process is presented to calculate the accurate rotation displacement. Subsequently, with reference to the initial state of rotation, the relative strain distribution caused by flaws is determined. Finally, the sensitivity of the strain is validated by comparing the three damage indicators including unbalanced rotational displacement, frequency change, and surface strain field. The performance of the proposed algorithm is verified by laboratory tests of blade damage detection and wind turbine model deformation monitoring. The study demonstrated that the proposed method provides an effective and robust solution for the operation status monitoring and damage detection of wind turbine blades. Furthermore, the strain-based damage detection algorithm is more advantageous in identifying cracks on rotating blades than one based on fluctuated displacement or frequency change. [ABSTRACT FROM AUTHOR]

Lead (Pb(II)) is a heavy metal with harmful effects on ecosystems and living organisms. Bacteria are used as part of the microorganisms involved in Pb(II) bioremediation. Herein, the effects of long-term (20 months) Pb(II) contamination (LTC) under a continuous sub-culturing system were evaluated on the growth rate, Pb-remediation potential, and Pb-remediation mechanisms of two strains, CM3 and CM7, of Microbacterium oxydans. LTC affected the optimal pH and temperature, and increased the growth rate of bacterial strains in the Pb(II) environment compared with native strains. Besides, the Pb-remediation potential of strains from LTC, CM3-b, and CM7-b, was significantly increased at pH 6.5. The biomass of strains was analyzed in terms of topographical and elemental percentage using SEM. LTC did not change the cell shape and dimensions of the studied strains. The Pb(II) percentage was significantly increased in sediments of the bacterial strains from LTC grown at pH 6.5, while the Pb(II) percentage was significantly reduced in the cell surface of strains grown under the LTC system. A correlation was found between P and Pb(II) percentage in the biomass of strains from LTC, indicating that these strains further precipitated Pb(II) in the form of lead phosphate. Furthermore, LTC reduced Pb(II) accumulation into the cell wall of strains. [ABSTRACT FROM AUTHOR]

SUMMARY: Geophysical imaging techniques together with numerical models have shown that the surface uplift measured above the Altiplano-Puna Magma Body (APMB) can be explained by the presence and propagation of a diapir from the top of the APMB itself. In this work, we model deformation that characterizes the crustal region above and around APMB through the use of a viscoplastic rheology. That is, we assume that at large scale the crust that surround the magmatic mushy diapir behaves as a yield-stress fluid described by the Herschel–Bulkley (HB) model, whereby motion develops only when the local deviatoric stress is greater than a critical value, the yield stress. In this scenario, laboratory and numerical results show that there are two main critical conditions needed for the growth and subsequent rise of a diapir: (1) the ratio between the yield stress and viscous stresses, namely the Bingham number Bi , has to be less than 1, that is Bi ≤ 1 and (2) the ratio between buoyancy stresses and the yield stress, namely the inverse Yield number Y inv, has to be larger than a critical value. Using these two conditions allows us to estimate the bulk rheological properties of the heterogeneous crust above APMB as a function of the diapir's size and density contrast with the crust. For the development of a 10–100 km wide diapir, 100–400 kg m–3 lighter than the surrounding crust, the crust yield stress should range between 0.5 and 15 MPa. Then, the regional uplift velocity measured at the surface implies a strain rate greater than ∼10−15–10−16 s−1 and a crust maximum bulk effective viscosity of ηc =1021 Pa.s. [ABSTRACT FROM AUTHOR]

Scaled model tests are the most extensively used methods for evaluating blasting performance. This study conducted the scaled model test of bench blasting to evaluate the stemming effect of the blast hole. Blasting experiments were conducted using emulsion explosives, wherein general stemming (sand) and shear-thickening fluid (STF)-based stemming materials were used in the blast hole. The blasting experiment results revealed that the STF-based stemming materials were superior to the general stemming material. In addition, the dynamic strain measurement results on the concrete surfaces of the high-speed three-dimensional digital image correlation system signified that the displacement and surface strain on the test models were the highest in the experimental case of STF-based stemming materials. [ABSTRACT FROM AUTHOR]

Summary: Complicated traffic scenarios, including random change in the speed and lane of vehicles, as well as the simultaneous presence of multiple vehicles on the bridge, are the main obstacles that prevent bridge weigh‐in‐motion (BWIM) technique from reliable and accurate application. To tackle the complicated traffic problems of BWIM, this paper develops a novel BWIM method, which integrates the deep‐learning‐based computer vision technique and bridge influence surface theory. In this study, bridge strains and traffic videos are recorded synchronously as the data source of BWIM. The computer vision technique is employed to detect and track vehicles and corresponding axles from traffic videos so that spatio‐temporal paths of vehicle loads on the bridge can be obtained, enabling the usage of the bridge strain influence surface (SIS) for BWIM purposes. Then the SIS of the bridge structure is calibrated based on the time‐synchronized strain signals and vehicle paths. After the SIS is calibrated, the axle weight (AW) and gross vehicle weight (GVW) can be identified by integrating the SIS, time‐synchronized bridge strain, and vehicle paths. For illustration and verification, the proposed method is applied to identify AW and GVW in scale model experiments, in which the vehicle‐bridge system is designed with high fidelity, and various complicated traffic scenarios are simulated. Results confirm that the proposed method contributes to improving the existing BWIM technique with respect to complicated traffic scenarios. [ABSTRACT FROM AUTHOR]

Monitoring alkali-silica reaction in pavements requires methods to quantify strain and deterioration. Typically, surface strain is measured using a detachable mechanical gauge, while deterioration features are measured following the damage rating index (DRI). External restraint from adjacent pavement or subgrade friction potentially affects strain and deterioration in the travel, transverse, and vertical directions differently, potentially decreasing deterioration in the restrained directions. Limited experimental data are available regarding states of stress observed in concrete pavements. The objective of this study was to evaluate the potential redistribution of strain and deterioration toward the unrestrained direction (vertical). Herein, surface strain and DRI methods were used to quantify and compare deterioration in restrained and unrestrained concrete cube specimens with self-reacting external restraint. The results were compared to previous studies to validate the findings. External restraint was found to limit strain and deterioration in the restrained directions, with a lesser effect on the unrestrained directions. [ABSTRACT FROM AUTHOR]

Pseudovertical Schottky barrier diodes (SBDs) are fabricated on a single‐crystal diamond substrate. Herein, the structural and electrical influence of laser‐induced graphitization which takes place during the laser‐dicing process is investigated. Before laser irradiation, the fabricated SBDs show a high rectifying ratio of more than 11 orders at ±10 V and undetectable leakage current. Ideality factor (n) and Schottky barrier height (ϕb) are estimated to be 1.09 and 1.35 eV, respectively. After laser irradiation, the SBDs still exhibit good diode behavior, in which n and ϕb values slightly change by 10%. Leakage current is increased about two orders of magnitude and breakdown voltage is degraded from 940 to 375 V due to the presence of graphite debris. After removing the graphite debris utilizing the oxygen plasma cleaning process through an inductively coupled plasma (ICP) system, all SBDs are recovered back to typical diode characteristics. It is found that strain and surface defects that may be introduced during laser dicing and post‐ICP etching do not severely influence SBD characteristics. [ABSTRACT FROM AUTHOR]

The surface structure and lattice strain necessary to optimize oxygen reduction reaction (ORR) in a cost‐effective electrocatalyst still requires systematic exploration. Here, by means of oxidative etching of surface confinement stacking faults, a comparative study of the influence of defects on the growth and lattice strain of PtAgPb core‐shell nanoplates for ORR is conducted. Stacking faults are key to forming the core–shell structure and induce tensile and compressive strains to improve catalytic performance of nanoplates. In particular, the compressive strain arising from the optimal composition of nanoplates enhances the ORR activity. The findings show how compressive strain in core–shell nanoplates shift the electronic band structure of platinum (Pt) and weakens chemisorption of oxygenated species. As a result, the obtained PtAgPb‐IV/C nanoplates display superior specific and mass activities (5.06 mA cm−2 and 2.24 A mgPt−1) for ORR that are ≈18 and ≈13 times higher than that of commercial Pt/C, placing it among the best reported Pt based ORR electrocatalysts. Furthermore, the PtAgPb‐IV/C catalyst exhibits substantially improved durability relative to commercial Pt/C catalysts. This work represents a major step toward the deterministic synthesis of Pt‐based multimetallic nanocrystals with specific structure and surface strain for efficient ORR performance. [ABSTRACT FROM AUTHOR]

Aero-engine turbine stator blades are often used in harsh environments with high temperatures and high pressure and are prone to fatigue fractures. Real-time and accurate monitoring of blade surface stress and strain is critical to ensure safe operation. In this study, thin-film strain gauges (TFSGs) that can be used in high-temperature environments above 1000 °C were designed and fabricated using a PtRh6 thin film as the sensitive material. The hysteresis effect of the stress transfer upon establishing a thermo-mechanical coupling finite element model of the Inconel718 high-temperature nickel-based alloy equal-strength beam PtRh6 TFSGs was analyzed and the optimal combination of thin-film thickness and longitudinal grid length of wire-grid TFSGs was determined. In order to solve the problem of high-temperature insulation, the insulating properties of a single-layer Al2O3 insulating film, a single-layer ZrO2 insulating film, a double-layer Al2O3/ZrO2 composite insulating film, and a four-layer Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film at high temperature were compared and studied using scanning electron microscopy to analyze the microscopic morphology and composition of the four insulating film structures. The results showed that the four-layer Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film had the best insulating properties at high temperatures. On this basis, an Al2O3/ZrO2/Al2O3/ZrO2 composite insulating film, PtRh6 sensitive layer, and Al2O3 protective film were sequentially deposited on a high-temperature nickel-based alloy equal-strength beam using DC pulsed magnetron sputtering technology to obtain an Inconel718 high-temperature nickel-based alloy equal-strength beam PtRh6 TFSG. Its gauge factor (GF) and temperature coefficient of resistance (TCR) were calibrated, and the results showed that the sensor could be used in harsh environments of 1000 °C. The above results provide new ideas for measuring stress and strain in aerospace under high-temperature and high-pressure environments. [ABSTRACT FROM AUTHOR]

The large volume expansion and self-locking phenomenon of metal hydride particles during hydrogen sorption often leads to a high stress concentration on the walls of a container, which may cause the collapse of the container. In present study, silicone oil was investigated as a glidant for a V-based BCC metal hydride bed to alleviate the stress concentration during hydrogen sorption. The results indicated that the addition of 5 wt% silicone oil slightly reduced the initial hydrogen storage capacity of V40Ti26Cr26Fe8 (particle size: ~325 μm) but improved the absorption reversibility, regardless of the oil viscosity. It was observed that silicone oil formed a thin oil layer of 320~460 nm in thickness on the surface of the V40Ti26Cr26Fe8 particles, which might improve the fluidity of the powder, reduce the self-locking phenomenon and alleviate the stress concentration on the container walls. Consequently, the maximum strain on the surface of the hydrogen storage container decreased by ≥22.5% after adding 5 wt% silicone oil with a viscosity of 1000 cSt. [ABSTRACT FROM AUTHOR]

The mining of valuable minerals from wastewater streams is attractive as it promotes a circular economy, wastewater beneficiation, and valorisation. To this end, the current study evaluated the rapid removal of aqueous Cr(VI) by polycationic/di-metallic Fe/Al (PDFe/Al) adsorbent recovered from real acid mine drainage (AMD). Optimal conditions for Cr(VI) removal were 50 mg/L initial Cr(VI), 3 g PDFe/Al, initial pH = 3, 180 min equilibration time and temperature = 45 °C. Optimal conditions resulted in ≥95% removal of Cr(VI), and a maximum adsorption capacity of Q = 6.90 mg/g. Adsorption kinetics followed a two-phase pseudo-first-order behaviour, i.e., a fast initial Cr(VI) removal (likely due to fast initial adsorption) followed by a slower secondary Cr(VI) removal (likely from Cr(VI) to Cr(III) reduction on the surface). More than 90% of adsorbed Cr(VI) could be recovered after five adsorption–desorption cycles. A reaction mechanism involving a rapid adsorption onto at least two distinct surfaces followed by slower in situ Cr(VI) reduction, as well as adsorption-induced internal surface strains and consequent internal surface area magnification, was proposed. This study demonstrated a rapid, effective, and economical application of PDFe/Al recovered from bona fide AMD to treat Cr(VI)-contaminated wastewater. [ABSTRACT FROM AUTHOR]

Novel, closely related phages Possum and Horatius infect Pectobacterium versatile, a phytopathogen causing soft rot in potatoes and other essential plants. Their properties and genomic composition define them as N4-like bacteriophages of the genus Cbunavirus, a part of a recently formed family Schitoviridae. It is proposed that the adsorption apparatus of these phages consists of tail fibers connected to the virion through an adapter protein. Tail fibers possess an enzymatic domain. Phage Possum uses it to deacetylate O-polysaccharide on the surface of the host strain to provide viral attachment. Such an infection mechanism is supposed to be common for all Cbunavirus phages and this feature should be considered when designing cocktails for phage control of soft rot. [ABSTRACT FROM AUTHOR]

Thermographic phosphors (TP) are combined with stereo digital image correlation (DIC) in a novel diagnostic, TP + DIC, to measure full‐field surface strains and temperatures simultaneously. The TP + DIC method is presented, including corrections for nonlinear CMOS camera detectors and generation of pixel‐wise calibration curves to relate the known temperature to the ratio of pixel intensities between two distinct wavelength bands. Additionally, DIC is employed not only for strain measurements but also for accurate image registration between the two cameras for the two‐colour ratio method approach of phosphoric thermography. TP + DIC is applied to characterize the thermo‐mechanical response of 304L stainless steel dog bones during tensile testing at different strain rates. The dog bones are patterned for DIC with Mg3F2GeO4:Mn (MFG) via aerosol deposition through a shadow mask. Temperatures up to 425°K (150°C) and strains up to 1.0 mm/mm are measured in the localized necking region, with conservative noise levels of 10°K and 0.01 mm/mm or less. Finally, TP + DIC is compared to the more established method of combining infrared (IR) thermography with DIC (IR + DIC), with results agreeing favourably. Three topics of continued research are identified, including cracking of the aerosol‐deposited phosphor DIC features, incomplete illumination for pixels on the border of the phosphor features, and phosphor emission evolution as a function of applied substrate strain. This work demonstrates the combination of phosphor thermography and DIC and lays the foundation for further development of TP + DIC for testing in combined thermo‐mechancial environments. [ABSTRACT FROM AUTHOR]

Skid lines on the outer panels of automobiles seriously affects their appearance and are a common surface manufacturing defect. In the die and process design stages, numerical simulation is needed to predict skid lines to take prevention measures. However, it is still a challenge to predict skid lines accurately. The simulation-based skid line criteria need further verification and improvement. Therefore, this paper takes a lightweight aluminum alloy AL6061-T6 sheet as its research object, uses a set of U-shaped dies to explore the influence of process parameters on skid lines, and establishes the correlation between skid lines and surface roughness based on visual and microscopic measurements. The relationships between contact pressure/inverse bending strain and surface roughness are established through simulation. Thus, a contact pressure and inverse bending strain dependent skid line criterion is constructed. The skid line criterion based on the simulation results has theoretical, guiding significance for the practice of engineering. [ABSTRACT FROM AUTHOR]

In this work, a curved surface convex roll (CSC-Roll) suitable for wide-thick slabs was designed. According to the field conditions and casting parameters, a 3D thermal-mechanical coupling model of CSC-Roll reduction was established, and the uneven solidification morphology of the slab was obtained. By analyzing the liquid core deformation rate, surface maximum stress and reduction force of the CSC-Roll with different shape parameters, the optimal shape parameters of the CSC-Roll were designed. By coupling the shrinkage void in the 3D thermal-mechanical coupling model, the coalescence degree of shrinkage voids under the flat reduction is calculated to be 8.78 pct, and that under CSC-Roll reduction is 9.68 pct, and the deformation degrees of the shrinkage voids in different directions were compared. The critical strain of slab surface crack propagation measured by high-temperature tensile test is 0.181. Based on the relationship between crack tip strain and initial crack length during reduction, the critical initial lengths of longitudinal and transverse crack propagation on slab surface were obtained to be 15.7 mm and 28.0 mm. [ABSTRACT FROM AUTHOR]

Composite materials are increasingly used in the wind industries. Damage detection and health monitoring of composite materials are challenging due to the complex internal structure and unique material properties. Digital image correlation (DIC) and acoustic emission (AE) are both used for damage detection in structures. In this work, DIC performs a full-field strain measurement on the surface of the carbon-fiber specimen while AE continuously monitors and records the AE signals generated from specimen subsurface structure failures. These health monitoring techniques are integrated and evaluated in this study to correlate surface strain measurements and acoustic emission measurements on carbon-fiber specimens. The AE measurement results show that there is a correlation between the occurrence of AE events and the timing of complete specimen failure. DIC with a high-speed stereo camera system is also adopted to extract the change in the resonance frequencies and displacement and strain mode shapes of the specimen during experiments in cyclic loading. [ABSTRACT FROM AUTHOR]

In this study, a novel biocontrol bacterium was isolated and identified as Paenibacillus sp. LYX-1 from soils in the peach orchard. Both Cd2+ resistance and biosorption behavior of strain LYX-1 was explored. Meanwhile, the Cd2+ resistance and biosorption mechanisms were further identified by Cd-resistant genes, SEM–EDS, FTIR, XPS, and TEM analysis. The results showed that strain LYX-1 could resist 50 mg/L Cd2+ and had the CzcD gene responsible for Cd2+ efflux. Under pH 8.0 and at a dose of 1.0 g/L sorbent dose, the removal efficiencies of living and dead cells were as high as 90.39% and 75.67% at 20 mg/L Cd2+, respectively. For the adsorption isotherm test, results revealed that both Langmuir (R2 = 0.9704) and Freundlich (R2 = 0.9915) model could describe the Cd2+ biosorption well for living strain LYX-1. The maximum equilibrium biosorption capacities of living and dead biomass were 30.6790 and 24.3752 mg/g, respectively. In the adsorption kinetic test, the adsorption process of both living and dead strain LYX-1 all satisfied the pseudo-second kinetic equation. A desorption study showed that strain LYX-1 sorbents could be recycled and regenerated by eluents efficiently. SEM–EDS analysis reflected that Cd2+ was bound to the cell wall. Besides, the biosorption process was controlled by chemisorption with the participation of the -OH, -NH, -C = O, O = C-O, C-N, S2−, and phosphate functional groups on the cell surface of strain LYX-1, which were identified by FTIR and XPS. Bioaccumulation also made a contribution to the Cd2+ removal during the biosorption process of living sorbent. The above results indicated that strain LYX-1 had higher Cd2+ tolerance and Cd2+ removal capacity. This strain exhibits promising application to the removal of Cd2+ in the Cd-contaminated environment. [ABSTRACT FROM AUTHOR]

With zero excess lithium, anode‐free lithium metal batteries (AFLMBs) can deliver much higher energy density than that of traditional lithium metal batteries. However, AFLMBs are prone to suffer from rapid capacity loss and short life. Monitoring and analyzing the capacity decay of AFLMBs are of great importance for their future applications. It is known that the capacity fade mainly comes from the formation of solid electrolyte interphase species and dead lithium, which leads to irreversible volume expansion. Therefore, monitoring and distinguishing the irreversible volume expansion or reversible volume expansion are the key points to analyze the capacity fade of AFLMBs. Herein, an applicable technique based on optical fiber sensors to characterize and quantize the volume change of AFLMBs is developed. By attaching fiber Bragg grating (FBG) sensors onto the surface of the multilayered anode‐free pouch cells, the strain evolution of the cells is successfully monitored and correlated with their electrochemical properties. It is found that the decline of surface strain fluctuation amplitude caused by the loss of active lithium is the leading indicator of battery failure. The proposed sensing technique has excellent multiplexing capability that can be considered as an elementary unit for capacity fade analysis in next‐generation battery management system. [ABSTRACT FROM AUTHOR]

Although significant progress is achieved for the synthesis of noble metal‐based nanocrystals (NCs), the construction of nanostructures with switchable dimensionality is not reported yet. Herein, a facile and general approach for the synthesis of multimetallic (PtCuPb and PtAgPb) NCs with dimensional‐switching properties by manipulating the reduction rate involved in the growth of 2D nanosheets (2D‐NS) and 1D nanowires (1D‐NW) is presented. At a slow reduction rate, PtCuPb and PtAgPb NCs grow to form 2D‐NS, in contrast, at a fast reduction rate, dimensionality alteration occurs to form 1D‐NW. This 2D‐NS to 1D‐NW transition generates compressive surface strain in PtCuPb‐NW with unique intermetallic core, active surface composition and exposes facet to boost oxygen reduction reaction (ORR). In PtCuPb‐NW, compressive strain shifting the d‐band electronic structure of platinum and weakening chemisorption of oxygenated species are shown. In detail, PtCuPb‐NW/C exhibits superior specific and mass activities (4.91 mA cm−2 and 2.65 A mgPt−1) for ORR that are ≈19 and ≈15 times higher than the commercial Pt/C. The observations made and chemical principles unveiled in this effort indicate that a general approach exists for dimensional‐switching and show a new class of Pt‐based electrocatalysts with enhanced performance for fuel cells. [ABSTRACT FROM AUTHOR]

Temperature and strain sensitivities of surface acoustic wave (SAW) and hybrid acoustic wave (HAW) Brillouin scattering (BS) in 1 ÎĽmâ€"1.3 ÎĽm diameter optical microfibers are simulated. In contrast to stimulated Brillouin scattering (SBS) from bulk acoustic wave in standard optical fiber, SAW and HAW BS, due to SAWs and HAWs induced by the coupling of longitudinal and shear waves and propagating along the surface and core of microfiber respectively, facilitate innovative detection in optical microfibers sensing. The highest temperature and strain sensitivities of the hybrid acoustic modes (HAMs) are 1.082 MHz/°C and 0.0289 MHz/ÎĽ ε, respectively, which is suitable for microfiber sensing application of high temperature and strain resolutions. Meanwhile, the temperature and strain sensitivities of the SAMs are less affected by fiber diameter changes, ranging from 0.05 MHz/°C/ÎĽm to 0.25 MHz/°C/ÎĽm and 1 Ă— 10âˆ'4 MHz/ÎĽ ε /ÎĽm to 5 Ă— 10âˆ'4 MHz/ÎĽ ε /ÎĽm, respectively. It can be found that that SAW BS for temperature and strain sensing would put less stress on manufacturing constraints for optical microfibers. Besides, the simultaneous sensing of temperature and strain can be realized by SAW and HAW BS, with temperature and strain errors as low as 0.30 °Câ€"0.34 °C and 14.47 ÎĽ ε â€"16.25 ÎĽ ε. [ABSTRACT FROM AUTHOR]

The paper presents a new advanced computational method for ultimate and nominal strength analysis of composite steel‐concrete cross‐sections with arbitrary shape subjected to elevated temperatures. The capacity diagrams are evaluated for a given bending‐moments ratio, generating plane and smooth distribution points on interaction diagrams. The ultimate (maximum) strength capacity is formulated as a problem of constrained mathematical optimization of the total bending moment, whereas the proposed approach evaluates the nominal strength capacity by means of enforcing the nonlinear equilibrium equations in conjunction with a total strain field tangent at the ultimate strain surface. Both methods are unified within the same strain‐driven algorithm used to solve the resulted nonlinear coupled equations. This algorithm coupled with a bracketing approach by means of combining Bisection and Newton method represents the main computational framework to ensure global convergence of the developed methods. An adaptive effective plastic centroid has been introduced ensuring that the origin of the reference axes is within the iso‐load contour circumventing in this way any potential convergence issues. The computational examples prove the effectiveness and the reliability of the proposed method. [ABSTRACT FROM AUTHOR]

An experimental investigation into the structural performance of wire arc additively manufactured (WAAM) steel single‐lap shear bolted connections is presented in this paper. Sixty specimens of different thicknesses, printing strategies and geometric features, including end distances and plate widths, were manufactured using steel wire of a nominal yield strength of 420 MPa and subjected to single shear lap tests. The test results are analysed while the observed failure modes, featuring shear‐out, net section tension fracture, end‐splitting, localised tearing and curl‐bearing failure, are discussed. Digital image correlation (DIC) was used for detailed monitoring and visualisation of the surface strain fields that developed during testing, providing valuable insight into the developed failure mechanisms. The experimental results, which generally followed the anticipated trends, were used to assess the applicability of current design specifications developed for conventional steel bolted connections to WAAM steel bolted connections. It was found that both the cold‐formed steel specifications (AISI S100 and AS/NZS 4600) and the structural steel specifications (AISC 360 and EN 1993‐1) yield considerable overestimations or underestimations of the test capacities, depending on the specimen geometry. Further research is underway to underpin the development of improved design provisions. [ABSTRACT FROM AUTHOR]