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This study explored the fracture process of granite cylinders with a centric charge, varying decoupling ratios by conducting laboratory-scale experiments and numerical simulations. In experiments, the three-dimensional (3D) digital image correlation (DIC) technique was employed, using frames captured by two synchronized high-speed cameras. This instrumentation permitted the observation of full-field strain variation, the development of fractures, and gaseous products escaping from the cylinders' surfaces. Granite cylinders measuring 240 mm in diameter and 300 mm in length served as specimens in blasting experiments, and each specimen had a charge of approximately 3 g. Specimens had a centric blasthole with a diameter of either 10 mm, 14 mm, or 20 mm. The corresponding decoupling ratio varied from 1.8 to 3.6, and the gap between the charge and the blasthole wall was filled with water or air. The experimental results showed that: (1) specimens with decoupling ratios of 1.9 and 2.6 exhibited initial strains on the cylindrical surface between 20 μs and 40 μs. (2) Specimens with water-filled blastholes developed fractures faster and in a denser manner compared to those with air-filled blastholes. In addition, fractures resulting from air-filled blastholes appeared smoother than those from water-filled blastholes. (3) The gas ejection time for the air-filled blasthole remained basically consistent across decoupling ratios ranging from 1.5 to 3.61, varying between 400 μs and 520 μs. The utilization of water-filled blastholes effectively minimized the escape of gaseous products from the cylindrical surface. Numerical simulation conducted with LS-DYNA exhibited results that aligned well with the observed fracture patterns in the experiments. This study aims to provide a better understanding of the fundamental mechanisms of rock behaviors in decoupled charge blasting. Highlights: Decoupled charge blasts were conducted on granite cylinders (⌀240mm×300mm) using the digital image correlation analysis and high-speed cameras. For specimens with decoupling ratios of 1.9 and 2.6, initial strains on the cylindrical surface were observed between 20-40 μs. Water-filled blasthole specimens developed fractures faster and denser compared to air-filled blasthole specimens. The decoupling ratio of 1.5-3.61 in air-filled blasthole specimens barely influenced gas ejection time, which varied from 400 μs to 520 μs. [ABSTRACT FROM AUTHOR]

The digital image correlation (DIC) system is a powerful tool for measuring distributions of displacement and strain on the surface of a specimen. DIC systems are employed not only for homogeneous materials such as metals but also for heterogeneous materials such as wood. Although numerous validations of DIC system accuracy for metallic materials exist, the accuracy verification for wood, especially under multiaxial stress conditions, is less common. This study investigated the accuracy of a DIC system equipped with a bilateral telecentric lens on wood (Douglas fir). The accuracy verification in uniaxial stress fields was conducted through full compression testing, while verification in multiaxial stress fields was performed through partial compression testing. Additionally, compression tests on A6063 (aluminium alloy) were conducted to examine the differences in the DIC system accuracy between homogeneous and heterogeneous materials. The accuracy of the DIC system was assessed by comparing the results with those obtained from strain gauges. The results from the full compression tests indicate that the accuracy of axial strain measured by the DIC system was comparable for the specimens of A6063 and Douglas fir in the longitudinal (L) direction but was inferior for Douglas fir in the radial (R) direction. This is because the differences in the mechanical properties of earlywood and latewood produce high strain gradients. Furthermore, the differences in Young's modulus obtained from the DIC system and strain gauge for the specimens of A6063, Douglas fir (L), and Douglas fir (R) were − 1.23%, 2.26%, and − 12.5%, respectively. In the partial compression tests, the accuracy of strain components measured by the DIC system in the specimens of Douglas fir (R) was lower than that in A6063. In the partial compression tests, high strain gradients appear in multiple strain components, leading to a notable decrease in the accuracy of the DIC system compared to the full compression tests. [ABSTRACT FROM AUTHOR]

Effect of the external surface layer on the phase transition (PT) between the low pressure phase and high pressure phase (HPP) in a NiAl bicrystal is investigated. Using a phase field model, the external surface layer is included, within which the elastic properties and surface energy are properly distributed. After resolving a stationary layer, the coupled phase field and elasticity equations are solved to capture the HPP evolution. Residual stress concentrator is included as a shear band representing an inelastic shear strain. Due to the small grain size, the surface layer can influence the stress distribution and consequently, the critical inelastic shear strain γ cr for the HPP growth. Above a certain applied pressure, the surface layer width Δ ξ shows no effect on γ cr , e.g., P = 10 GPa for the grain size of L = 20 nm. For lower pressures, γ cr increases as pressure reduces. Due to the interplay of size addition by the surface layer and size reduction by the transformation strain, γ cr reduces versus Δ ξ and then increases for larger Δ ξ . For smaller grain sizes, the surface layer effect is promoted as it is imposed to a larger transformation work. The lowest γ cr is obtained for P = 19 GPa, in good agreement with the theoretical pressure of 20 GPa. Combining the external shear on pressure adds an extra shear term to the transformation work, which allows for the relaxation of the shear band and results in a nonlinear reduction of the PT pressure versus applied shear. [ABSTRACT FROM AUTHOR]

ABSTRACT This work introduces a damage index (DI) that combines the effective plastic strain and surface roughness changes to predict the future propagation path of a microstructure‐sensitive crack (MSC) in a polycrystalline nickel fatigue sample. The surface topography of a fatigue sample was measured at short fatigue intervals, from which both the effective plastic strain and surface roughness changes were calculated using digital image correlation (DIC). Three DIs based on the effective plastic strain, surface roughness changes, and their combinations were studied using two criteria, that is, the highest intensity and the confidence threshold. Comparing the crack path predicted by these DIs with the actual crack path acquired at later fatigue cycles, we demonstrated that the combined DI is more accurate and has less uncertainty in predicting the future crack path. [ABSTRACT FROM AUTHOR]

Fault slip rates estimated from geodetic data are being integrated into seismic hazard models. The standard approach requires modeling velocities and relative (micro‐)plate motions, which is challenging for fault‐based models. We present a new approach to directly invert strain rates to solve for slip rates and distributed strain simultaneously. We generate velocity and strain rate fields over the southeastern Tibetan Plateau, utilizing Sentinel‐1 Interferometric Synthetic Aperture Radar data spanning 2014–2023. We derive slip rates using block modeling and by inverting strain rates. Our results show a partitioning between localized strain on faults and distributed deformation. The direct inversion of strain rates matches the geodetic data best when incorporating distributed moment sources, accounting for a similar proportion to on‐fault sources. The direct strain methodology also aligns best with the independent geological slip rates, especially near fault tips. As high‐resolution strain rate fields become increasingly available, we recommend direct inversion as the preferred practice. Plain Language Summary: We focus on understanding earthquake potential in the southeastern Tibetan Plateau by measuring how and how fast the crust deforms. By analyzing 9 years of satellite radar images, we estimate how fast faults are slipping, which is crucial for assessing the hazard of future earthquakes. We tested two methods and found that the method directly incorporating measurements of surface strain rates provides more accurate results when compared to field‐based geologic slip rates. We show that the total deformation field is roughly equally split between energy accumulation on mapped active faults and distributed deformation away from the faults. The large amount of diffuse strain is an important constraint for rates of background seismicity. We discuss the limitations of various techniques used in modeling Earth's interseismic deformation and suggest prioritizing the direct strain methodology. Key Points: We construct velocity and strain rate fields covering 1.3 million km2 of SE Tibet from Sentinel‐1 Interferometric Synthetic Aperture RadarDeformation is partitioned approximately equally between focused strain on the main mapped faults and diffuse deformationDirect inversion of strain rates removes the requirement to define artificial "blocks" and gives a better match to geological slip rates [ABSTRACT FROM AUTHOR]

In this study, we utilize C‐band Sentinel‐1 radar images from 2015 to 2022, combined with interseismic horizontal GNSS velocities, to construct large‐scale, high‐resolution, 3‐D velocity and strain rate maps over a vast region of southern Tibet. We show the distribution of prevailing dilatational strain accumulation along the seven major rift zones. Using 2‐D elastic dislocations invoking a two‐fault model in a Bayesian framework, we quantified the decadal extension rates across the seven rift zones, and we suggest a total extension rate of 18.4 ± 1.7 mm/yr, consistent with geological and geodetic estimates. The resulting strain rate maps, combined with the earthquake catalog, help us identify areas with high earthquake potential. Our study enhances our understanding of the present‐day tectonics and kinematics in southern Tibet and provides important constraints for seismic hazard assessment in this region. Plain Language Summary: In this research, we used satellite radar images from 2015 to 2022 and GNSS data to study the crustal deformation and strain distribution in southern Tibet, where the Earth's crust is actively stretching due to the collision of the Indian and Eurasian plates and the extrusion of crustal materials. By analyzing high‐resolution 3D velocities, we provided new high‐resolution surface strain maps over southern Tibet. We found that the widespread dilatational strain is mainly localized along seven major N‐S trending rift zones. Seven major rift zones are experiencing extension at a total rate of 18.4 ± 1.7 mm/yr. The strain rate maps, combined with historical earthquakes, helped us identify fault segments that are more likely to host earthquakes in the future. By mapping deformation and strain in greater detail, we provided valuable data that can improve our understanding of kinematics and earthquake risk assessments in geologically complex southern Tibet. Key Points: We present InSAR‐based, high‐resolution maps of 3‐D velocities and strain rates in Southern TibetThere is prevailing dilatational strain along seven rift zones in Southern Tibet, with a total extension rate of 18.4 ± 1.7 mm/yrWe show the distribution and spatial variations of extension rates for seven rift zones [ABSTRACT FROM AUTHOR]

Strain engineering is a promising approach to control the oxygen reduction reaction (ORR) kinetics of perovskite cathodes in solid oxide fuel cells (SOFCs). For multi-component oxide materials such as perovskite, there are two main strain effects: altering the surface reactivity and modifying the surface chemical composition. Our previous study (Energy Environ. Sci. 11 (2018) 71–77) showed that applying tensile strain enhances the oxygen exchange kinetics on SrTiFeO 3−δ (STF) surfaces by suppressing Sr segregation. However, the potential impact of changes in surface reactivity by strain on the oxygen exchange kinetics of STF remains unexplored yet. To address this gap, density functional theory (DFT) calculations are performed to evaluate the strain effect on oxygen incorporation on SrO and (Ti,Fe)O 2 (001) terminations of STF surfaces. The presence of surface vacancies is necessary for O 2 activation and dissociation. With the assistance of oxygen vacancies, O 2 incorporation is favorable on the (Ti,Fe)O 2 surface over the SrO surface. Tensile strain facilitates O 2 incorporation kinetics on the (Ti,Fe)O 2 surface, but its effect is weak on the SrO surface. Our results demonstrate that the enhanced oxygen surface exchange kinetics due to tensile strain in STF result not only from the inhibition of Sr segregation but also from an increase in O 2 incorporation. [Display omitted] • DFT study of O 2 incorporation on two terminated surfaces of SrTiFeO 3 (001). • Surface V O are vital for O 2 incorporation on both (Ti,Fe)O 2 and SrO surfaces. • Biaxial strain boosts O 2 incorporation on (Ti,Fe)O 2 , minimally affecting SrO. • This work elucidates the experimentally observed link between strain and surface oxygen exchange. [ABSTRACT FROM AUTHOR]

A fully biodegradable, ultra‐sensitive, and soft strain sensor is pivotal for temporary, real‐time monitoring of microdeformations, crucial in disease diagnosis, surgical precision, and prognosis of muscular, and vascular conditions. Nevertheless, the strain sensitivity of previous biodegradable sensors, denoted by gauge factor (GF) up to ≈100, falls short of requirements for complex biomedical monitoring scenarios, specifically monitoring cardio‐cerebrovascular diseases with microscale variations in vascular surface strain. Here, a fully biodegradable, ultra‐sensitive crack‐based flexible strain sensor is introduced achieving GF of 1355 at 1.5% strain through integration of molybdenum (Mo) film, molybdenum trioxide (MoO3) adhesion layer, and polycaprolactone (PCL) substrate. Analysis of crack morphology of biodegradable thin‐film metals, including Mo, tungsten (W), and magnesium (Mg), reveals material‐dependent sensitivity and repeatability of crack‐based strain sensors. The effect of the adhesion layer and polymer substrate is also investigated. Overall morphological studies on the sensor present a comprehensive understanding of metal film cracking behavior and corresponding performance characterization, showing significant potential for highly sensitive sensors. A hybrid membrane composed of candelilla wax (Cw), beeswax (Bw), and polybutylene adipate‐co‐terephthalate (PBAT) is introduced to provide hydrophobic, yet flexible encapsulation. In vivo, short‐term (≈3 days) monitoring of vascular pulsatility underscores the potential of the sensing tool for rapid, accurate, and temporal disease diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) has gained popularity due to reduced production times of low-cost and geometrically complex structures. Due to technological constraints such as print volume, time, and thermal stability of large AM parts, adhesive joints are commonly used in assembling smaller components in large-scale polymeric structures. This work investigates the feasibility of using embedded optical fibers to monitor strain distributions within AM composite (carbon fiber/nylon) single-lap shear (SLS) joints. Internal strain distributions within the adhesive and surface strain fields of the SLS joints with AM adherends under tensile loads were obtained using optical fibers and digital image correlation, respectively. Results indicate negligible influence of optical fibers on the failure strength and axial stiffness of 3D-printed SLS joints under quasi-static loading. Higher strains were observed at the bond edges within the adhesive (using optical fiber) and the surface (using DIC) of the joints due to the rotation of the bond under loading. All specimens failed in the adherends beyond the bonded region due to their low interlaminar strength. [ABSTRACT FROM AUTHOR]

Background: The experimental detection of small and large strains requires special approaches of full-field measurement techniques and their evaluation on 3D curved surfaces of components. Objectives: Since classical digital image correlation methods have difficulties with the application of paints in some applications, one aim is to use a method in which the surface roughness is used to apply the strain calculation. Methods: In this paper, 2D digital image correlation is applied to 2D intensity maps extracted from a coherence scanning interferometer together with height information. Height information are used to reconstruct the 3D motion of tracked material points. Surface interpolation and strain calculation are performed using globally formulated radial basis functions. Results: The entire procedure leads to an appropriate technique for determining the in-plane strains in curved surfaces of parts, whereas the expected accuracy for various levels of the radial basis functions are discussed in detail. Conclusions: Particularly, coherence scanning interferometry yields highly accurate height information. To smooth the surface motion, it turns out that in particular a regression analysis is required, where we apply radial basis functions with various approximation levels. This is an alternative procedure for surface strain determination. [ABSTRACT FROM AUTHOR]

This paper investigates and analyzes the dynamic response of asphalt pavement under pavement-unevenness excitation based on an orthogonal vector function system and efficient DVP (dual variable and position) method. Firstly, starting from the pavement unevenness of the vehicle excitation source, the pavement-unevenness excitation is established by using the filtered white-noise method, and the random load of the vehicle model is obtained by simulation. Then, based on the basic governing equation of the road-surface problem under the random load, the analytical solution of the road-surface mechanical response is obtained by using the orthogonal vector function system and DVP method. The effects of pavement-unevenness grade, vehicle speed, vehicle load, interlayer contact condition, and transverse isotropy on the mechanical response of the road surface are analyzed via the analytical results. The results show that DVP can effectively solve the dynamic response of pavements under the excitation of pavement unevenness; in addition, it can also be applied to certain situations, such as transverse isotropy of materials and interface conditions. The results show that the pavement unevenness does not affect the average stress and strain of each layer but has a significant effect on the peak value and dispersion degree. An increase in vehicle speed causes a peak in strain and a larger coefficient of variation. Poor bonding between interfaces can lead to increased stress and strain at the bottom of the surface layer. [ABSTRACT FROM AUTHOR]

Face‐centered cubic (fcc) metals deposited onto crystalline substrates grow heteroepitaxially with specific orientation relationships (ORs). The ORs depend on a number of factors including lattice mismatch, bonding and the relative symmetry between the surface and the film. Less explored factors include defects like growth and annealing twins. In this study, a high density of nanotwins in as‐deposited films delay grain growth of OR1 ({111}fcc∥(0001)Al2O3$\left(\left{\right. 111 \left.\right}\right)_{f c c} \parallel \left(\left(\right. 0001 \left.\right)\right)_{A l_{2} O_{3}}$, ⟨110⟩fcc∥⟨101¯0⟩Al2O3$\left(\langle 110 \rangle\right)_{f c c} \parallel \left(\langle 10 \bar{1} 0 \rangle\right)_{A l_{2} O_{3}}$) grains up to 0.56 Tm. A new OR with respect to the c‐sapphire substrate is found, compared to the well‐known OR1 and OR2 which grow with the {111}fcc$\left(\left{\right. 111 \left.\right}\right)_{f c c}$∥(0001)Al2O3$$ \parallel {(0001)}_{A{l}_{2}{O}_{3}}$$. This is named OR3, grows above 0.56 Tm with {001}fcc∥(0001)Al2O3,⟨100⟩fcc∥⟨101¯0⟩Al2O3$\left(\left{\right. 001 \left.\right}\right)_{f c c} \parallel \left(\left(\right. 0001 \left.\right)\right)_{A l_{2} O_{3}} , \left(\langle 100 \rangle\right)_{f c c} \parallel \left(\langle 10 \bar{1} 0 \rangle\right)_{A l_{2} O_{3}}$. The OR3 growth is related to strain and defect energy advantage. An unusual OR {345}fcc∥(0001)Al2O3$\left(\left{\right. 345 \left.\right}\right)_{f c c} \parallel \left(\left(\right. 0001 \left.\right)\right)_{A l_{2} O_{3}}$accompanies OR3 in most films, occupying an area fraction of >0.3. A minute (<0.05) but consistent fractions of {447}fcc$$ \{447{\}}_{fcc},$$, {115}fcc$$ \{115{\}}_{fcc}$$, {221}fcc$$ \{221{\}}_{fcc}$$, {236}fcc$$ \{236{\}}_{fcc}$$ and 146fcc$$ {\left\{146\right\}}_{fcc} $$ all parallel to 0001Al2O3$$ {\left(0001\right)}_{A{l}_{2}{O}_{3}}$$ and related to annealing twins in exact and near {001}fcc$\left(\left{\right. 001 \left.\right}\right)_{f c c}$ and {111}fcc$\left(\left{\right. 111 \left.\right}\right)_{f c c}$ grains are observed. The study opens new directions in the crystallography of ORs, considering the role of twins in addition to the surface and strain energies. [ABSTRACT FROM AUTHOR]

Engineering strain critically affects the properties of materials and has extensive applications in semiconductors and quantum systems. However, the deployment of strain-engineered nanocatalysts faces challenges, in particular in maintaining highly strained nanocrystals under reaction conditions. Here, we introduce a morphology-dependent effect that stabilizes surface strain even under harsh reaction conditions. Using four-dimensional scanning transmission electron microscopy (4D-STEM), we found that cube-shaped core-shell Au@Pd nanoparticles with sharp-edged morphologies sustain coherent heteroepitaxial interfaces with larger critical thicknesses than morphologies with rounded edges. This configuration inhibits dislocation nucleation due to reduced shear stress at corners, as indicated by molecular dynamics simulations. A Suzuki-type cross-coupling reaction shows that our approach achieves a fourfold increase in activity over conventional nanocatalysts, owing to the enhanced stability of surface strain. These findings contribute to advancing the development of advanced nanocatalysts and indicate broader applications for strain engineering in various fields. [ABSTRACT FROM AUTHOR]

Triple‐cation mixed‐halide (TCMH), i.e., (FAPbI3)1‐x‐y(MAPbBr3)y(CsPbI3)x, perovskite single‐crystal thin‐films (SCTFs) have emerged as candidates for high‐performance photodetectors. However, high lattice strain, surface defects, and the non‐ideal yellow phase such as δ‐FAPbI3 and δ‐CsPbI3, are impeding the realization of high‐quality TCMH SCTFs. Therefore, the synthesis of pure‐phase, high‐quality TCMH SCTFs with low lattice strain and defect density is imperative for enhancing light absorption and carrier mobility, thereby optimizing photoresponsivity. Herein, an innovative approach is proposed for synthesize TCMH SCTFs using an optimized space‐limited anti‐solvent assisted crystallization technique which employs 2‐methoxyethanol as the solvent and diethyl ether as anti‐solvent, devoid of thermal enhancement. A novel reducing additive, formic acid, is incorporated to mitigate phase separation, and the composition ratio is meticulously adjusted to regulate lattice strain. The results show that a pure‐phased optimal composition ratio (FA0.82MA0.11Cs0.07) SCTF with a low surface defect density (2.29 × 109 cm−2), low lattice strain (0.81%) and high hole mobility (77.58 cm−2 V−1 s−1) is successfully prepared. Moreover, the non‐integrated planar FA0.82MA0.11Cs0.07 SCTF photodetector also achieved a record photo‐responsivity (229.5 A W−1), and external quantum efficiency (5.4 × 104%), indicating its great potential in light‐detecting. This research paves the way for the development of high‐performance photodetectors via adjusting lattice strain and mitigating surface defects in TCMH SCTFs. [ABSTRACT FROM AUTHOR]

Electrodeposited Invar alloy film is highly desirable for manufacturing fine metal masks (FMMs) used in Organic Light-Emitting Diodes (OLEDs). However, its development is limited by the high coefficient of thermal expansion (CTE). In this study, we successfully obtained a coarse-grained electrodeposited Invar alloy film with near-zero thermal expansion and inclusions smaller than 300 nm, achieved through abnormal grain growth (AGG) induced by second-phase particles. Our experiments confirmed that these second-phase particles are composed of (Fe, Ni)1-xS. During AGG, the aggregation and coarsening of these second-phase particles lead to changes in local strain energy, and the combined effects of surface and strain energies results in the rapid preferential growth of (110)-oriented grains. The matrix grains are engulfed by large-sized grains and transformed into sub-grains, which merge with the abnormally growing grains through grain rotation. An inverse relationship was found between CTE and grain size. Following vacuum annealing at 800 °C for 2 h and hydrogen annealing for 1 h, the average grain size increased to approximately 400 µm, while the CTE was reduced to 0.3 × 10–6/ °C. This study provides a new method for obtaining electrodeposited Invar alloy films that meet commercial applications criteria for and are suitable for FMM fabrication for high-definition OLEDs. [ABSTRACT FROM AUTHOR]

Strain engineering serves as an effective method for optimizing electronic and optical properties in semiconductor devices, with applications including the enhancement of optical emission in Ge and GeSn‐based devices, improvement of carrier mobility, and second harmonic generation in silicon photonics structures. Current methods for deformation characterization in semiconductors, such as X‐ray diffraction and Raman spectroscopy, often require bulky and expensive setups and are limited in vertical resolution. Consequently, techniques capable of measuring lattice strain while overcoming these drawbacks are highly desirable. This study proposes a proof of concept for a cost‐effective, compact, fast, and non‐destructive approach to probe non‐uniform strain fields and additional material properties by exploiting the bulk photovoltage effect. The method is benchmarked with an array of silicon nitride stripes deposited under varying pressure conditions on a germanium substrate. Initially, their surface strains are verified through Raman spectroscopy. The deformations are replicated in a finite element method platform by integrating mechanical simulations with deformation potential theory, thereby estimating the band edge energy landscape. Finally, the study discusses the theoretical behavior of the photovoltage signal, considering semiconductor properties, defects, doping, and deformation. The findings offer insights into the development of advanced techniques for strain and transport analysis in semiconductor materials. [ABSTRACT FROM AUTHOR]

Cubic‐garnet solid electrolyte has garnered significant attention in all‐solid‐state batteries (ASSBs) due to its ionic conductivity and chemical robustness against Li metal. However, the short‐circuit formation at low current density poses a significant obstacle with the main cause remaining ambiguous. Here, the lithium‐penetration mode originating from phase transformation is unveiled at the sintered pellet surface via mechanically induced lithiation. Mechanical stress applied during polishing under excess lithium content induces lithiation into the cubic‐garnet structure, leading to partial structural evolution into the tetragonal phase. This surface alteration induces current constriction, hindered by sluggish interfacial Li‐ion transport from the tetragonal phase, which exhibits low ionic conductivity, causing short circuits. By reducing mechanical stress, mitigating surface strain, and restoring the cubic phase, stable operation is ensured without short‐circuit formation in both Li symmetric and hybrid‐full cells. This insights illuminate the origin of lithium penetration related to phase transition at the surface of cubic‐garnet and pave the way for enhancements in ASSB development. [ABSTRACT FROM AUTHOR]

Models of active deformation of the Earth's crust are predominantly represented with dislocations having a downdip continuation into the lower crust, where the fault slips continuously. This model predicts surface strain accumulation concentrated near the fault during the interseismic period. In an alternative model, faults do not extend beneath the elastic portion of the crust and are accompanied by a wide zone of distributed shear underneath, predicting a more constant strain rate lacking concentrations at the faults. We use high‐precision GPS data collected across the northern and central Walker Lane, USA— a region of complex faulting near the western edge of the Basin and Range Province to evaluate which model is appropriate. Despite the existence of dense continuous and semi‐continuous geodetic networks that have been surveyed for ∼20 years, the horizontal velocities reveal no evidence of localized strain accumulation across the fault surface expressions. Instead, deformation within the Walker Lane is uniformly linear, suggesting that the surface deformation reflects distributed shear within the ductile crust rather than focused deformation at faults. This suggests no downdip extension of the faults below the seismogenic layer. The shear zone is 172 ± 6 km wide in the northernmost Walker Lane narrowing to 116 ± 4 km in the central Walker Lane. The total velocity budget across the shear zone is 7.2 ± 0.1 mm/yr in the north, increasing to 10.1 ± 0.1 mm/yr in the central Walker Lane. We conclude that assuming the presence of lower crustal dislocations when estimating geodetic faults slip rates may be inappropriate. Plain Language Summary: Interpreting Earth's surface deformation, measured by high‐precision GPS stations, is crucial for understanding plate tectonics and assessing seismic hazard. Traditionally, the assumption has been that faults in the Earth's upper crust extend as discrete dislocations into the lower crust. In this paper, we show that there is no compelling evidence of this in the Northern Walker Lane region of California and Nevada. Instead, the geodetically measured deformation on the surface reflects uniform shearing in the lower crust. Our findings suggest that estimating slip rates on the faults with methods that assume deep dislocations may be inappropriate. Instead, the slip rate of a fault is likely to be controlled by the fault's position and orientation within the shear zone. This has significant implications for seismic hazard assessment, as accurate estimates of slip rates on faults are a crucial component in determining seismic risk. Key Points: Geodetic velocities in the Walker Lane reflect distributed shear in the lower crust rather than deformation due to discrete faultsEstimating fault slip rates with models assuming their continuation into the lower crust may be inappropriate in the northern Walker Lane [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing enables the production of components with high deposition rates and the incorporation of multiple materials. However, the manufactured components possess a wavy surface, which is a major difficulty when it comes to simulating the mechanical behavior of wire arc additively manufactured components and evaluation of experimental full-field measurements. In this work, the wavy surface of a thick-walled tube is measured with a portable 3D scanning technique first. Then, the surface contour is considered numerically using the finite cell method. There, hierarchic shape functions based on integrated Legendre polynomials are combined with a fictitious domain approach to simplify the discretization process. This enables a hierarchic p-refinement process to study the convergence of the reaction quantities and the surface strains under tension–torsion load. Throughout all considerations, uncertainties arising from multiple sources are assessed. This includes the material parameter identification, the geometry measurement, and the experimental analysis. When comparing experiment and numerical simulation, the in-plane surface strains are computed based on displacement data using radial basis functions as ansatz for global surface interpolation. It turns out that the finite cell method is a suitable numerical technique to consider the wavy surface encountered for additively manufactured components. The numerical results of the mechanical response of thick-walled tubes subjected to tension–torsion load demonstrate good agreement with real experimental data, particularly when employing higher-order polynomials. This agreement persists even under the consideration of the inherent uncertainties stemming from multiple sources, which are determined by Gaussian error propagation. [ABSTRACT FROM AUTHOR]

This work develops a polarization-dependent analytical model using terahertz time-domain spectroscopy (THz-TDS) for computing strain in materials. The model establishes a correlation between volumetric strain and the change in time of arrival for a THz pulse by using the dielectrostrictive properties, variations in doping particle density, and changes in the thickness of the sample resulting from Poisson's effects. The analytical model is validated through strain mapping of polydimethylsiloxane (PDMS) doped with passive highly dielectrostrictive strontium titanate (STO). Two experiments, using an open-hole tensile and a circular edge-notch specimen are conducted to show the efficacy of the proposed. The stress relaxation behavior of the composite is measured and accounted for to prevent changes in strain during the measurement window. The THz strain mapping results are compared with the finite element model (FEM) and surface strain measurements using the digital image correlation (DIC) method. The experimental findings exhibit sensitivity to material features such as particle clumping and edge effects. The THz strain map shows a strong agreement with FEM and DIC results, thus demonstrating the applicability of this technique for surface and sub-surface strain mapping in polymeric composites. [ABSTRACT FROM AUTHOR]

AISI 301LN metastable austenitic stainless steels (MASSs) are known to exhibit high work‐hardening rates attributed to martensite evolution during straining which results in the second‐phase strengthening mechanism. This enhances surface hardness and potentially reduces wear and rolling contact fatigue (RCF). The aim of this study is therefore to evaluate the work hardening, wear, and RCF performance of AISI 301LN metastable austenitic stainless steel as a possible alternative material for rolling and sliding applications by varying the contact conditions such as slip ratio against the standard R350HT rail steel using a twin‐disc simulator. The results show that 301LN MASS has high surface work hardening and increased hardness because of martensitic transformation, while R350HT rail steel has only slightly changed. The formation of a hard martensitic phase is also confirmed by X‐ray diffraction analysis as well as by two other techniques, indicating a secondary hardening effect. Although it shows potential for work hardening, its susceptibility to wear‐related problems may make it less suitable for rolling and sliding applications due to a cracking and spalling mechanism induced by martensite formation. The surface strains required for the observed martensite formation are calculated and found to be very high, approaching 0.4. [ABSTRACT FROM AUTHOR]

Background: The damage and failure behavior of ductile metals depends on the stress state as well as on the loading history. Biaxial experiments with suitable specimens can be used to targeted generate different loading conditions, thus allowing the investigation of a wide variety of load cycles with different stress states. Objective: In the biaxial experiments with the newly presented HC-specimen cyclic shear loads are superimposed by various constant compressive and tensile loads. Buckling during compressive loading in both axes is avoided by an additional newly introduced downholder. Methods: The strain fields at the surfaces of the biaxial specimens are evaluated by digital image correlation (DIC), and after failure the corresponding fracture surfaces are analyzed by scanning electron microscopy (SEM). Associated numerical simulations employing the presented material model provide information on the current stress states. Results: The introduced downholder successfully prevents buckling during compressive loading. The strain fields detect a clear influence of the shear direction and a tensile superposition of the cyclic shear load leads to more brittle and a compressive superposition to more ductile behavior. The accompanying numerical calculations reveal the associated, different stress states. Conclusions: The new experimental program with biaxially loaded specimens for the investigation of damage and failure behavior under cyclic loading enables the targeted examination of a wide variety of load cycles and is thus suitable for the comprehensive analysis of these phenomena. [ABSTRACT FROM AUTHOR]

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Background: Facet fractures are frequently associated with clinically observed cervical facet dislocations (CFDs); however, to date there has only been one experimental study, using functional spinal units (FSUs), which has systematically produced CFD with concomitant facet fracture. The role of axial compression and distraction on the mechanical response of the cervical facets under intervertebral motions associated with CFD in FSUs has previously been shown. The same has not been demonstrated in multi‐segment lower cervical spine specimens under flexion loading (postulated to be the local injury vector associated with CFD). Methods: This study investigated the mechanical response of the bilateral inferior C6 facets of thirteen C5‐C7 specimens (67±13 yr, 6 male) during non‐destructive constrained flexion, superimposed with each of five axial conditions: (1) 50 N compression (simulating weight of the head); (2‐4) 300, 500, and 1000 N compression (simulating the spectrum of intervertebral compression resulting from neck muscle bracing prior to head‐first impact and/or externally applied compressive forces); and, (5) 2 mm of C6/C7 distraction (simulating the intervertebral distraction present during inertial loading of the cervical spine by the weight of the head). Linear mixed‐effects models (α = 0.05) assessed the effect of axial condition. Results: Increasing amounts of intervertebral compression superimposed on flexion rotations, resulted in increased facet surface strains (range of estimated mean difference relative to Neutral: maximum principal = 77 to 110 με, minimum principal = 126 to 293 με, maximum shear = 203 to 375 με) and angular deflection of the bilateral inferior C6 facets relative to the C6 vertebral body (range of estimated mean difference relative to Neutral = 0.59° to 1.47°). Conclusions: These findings suggest increased facet engagement and higher load transfer through the facet joint, and potentially a higher likelihood of facet fracture under the compressed axial conditions. [ABSTRACT FROM AUTHOR]

Ca-doped BiFeO3/LaNiO3/LaAlO3 (BCFO/LNO/LAO) heterostructures have garnered significant interest due to their unique combination of ferroelectric, magnetic, and resistive switching properties due to interfaces and lattice mismatch/strain, leading to unique electronic properties. The roles of structural defects and oxygen vacancies are important in achieving the magnetic and electrical properties of BiFeO3-based heterostructures. By generating defects, swift heavy ion irradiation can lead to changes in the structural, optical, electrical, and magnetic properties of the materials. The Ca-doped BiFeO3 and LaNiO3 heterostructure was grown upon LAO substrates using the pulsed laser deposition technique, ensuring high-quality interfaces and controlled thicknesses. The heterostructures were irradiated with 80 MeV O+7 ions at various ion fluence levels (5 × 1010 ions/cm2 to 5 × 1012 ions/cm2). The structure and crystalline orientation of the thin films were confirmed through x-ray diffraction, while the surface morphology was measured using atomic force microscopy. Irradiation-induced modifications of the structural strain and surface morphology were investigated in the context of internal annealing effect and defect formation. The resistive switching (RS) properties of the proposed devices were assessed by I–V measurement with sweeping 0 → 5 V → 0 → − 5 V → 0, which shows that irradiation-induced defects play an important role in the electrical properties of the proposed heterostructure. Bipolar RS behavior was also verified with the conduction mechanism, indicating that the ohmic and space-charge-limited conduction mechanism plays an important role in irradiated BCFO/LNO/LAO heterostructures. Graphical representation of the defect formation and RS behavior due to varying ion fluence as a function of RMS roughness and strain. [ABSTRACT FROM AUTHOR]

To reduce the amount of ordinary concrete and then reduce carbon dioxide emission, improving the engineering application range of self-compacting fly ash concrete (FASCC), this study explored the bond–slip traits between FASCC and a steel tube. Six samples were created, and bond–slip push-out tests were performed with varying concrete strength grades and steel tube internal setups. Digital image correlation (DIC) technology was applied to track the surface strain of four samples throughout the experiment. The results show that the outer surface of the steel tube stays mostly undistorted after the concrete is pushed out. Prior to reaching peak load, the load–slip curves of each specimen exhibit a primarily linear load–displacement relationship. Post-peak, the curves diverge into two distinct patterns, namely a sudden drop and a gradual decline. As the strength grade of the inner concrete increases, the interfacial bond between the steel tube and FASCC improves. Additionally, under the same conditions, the internal structure of the steel tube significantly enhances bonding strength. The FA40-Z specimen shows a maximum load that is 25.6% and 53.7% higher than the FA40-G and FA40-C specimens, respectively. The strain evolution patterns of steel tubes within FASCC and regular self-compacting concrete demonstrate similar characteristics. These observations provide valuable insights for the application of FASCC in engineering projects. [ABSTRACT FROM AUTHOR]

Submesoscale flows (0.1–10 km) are often associated with large vertical velocities, which can have a significant impact on the transport of surface tracers, such as carbon. However, global models do not adequately account for these small‐scale effects, which still require a proper parameterization. In this study, we introduced a passive tracer into the surface mixed layer (ML) of a northern Atlantic Ocean simulation based on the primitive‐equation model CROCO, with a horizontal resolution of Δx = 800 m, aiming to investigate the seasonal submesoscale effects on vertical transport. Using surface vorticity and strain rate criteria, we identified regions with submesoscale fronts and quantified the associated subduction, that is the export of tracer below the ML depth. The results suggest that the tracer vertical distribution and the contribution of frontal subduction can be estimated from surface strain and vorticity. Notably, we observed significant seasonal variations. In winter, the submesoscale fronts contribute up to 40% of the total vertical advective transport of tracer below the ML, while representing only 5% of the domain. Conversely, in summer, fronts account for less than 1% of the domain and do not contribute significantly to the transport below the ML. The findings of this study contribute to a better understanding of the seasonal water subduction due to fronts in the region. Plain Language Summary: Oceanic fronts are dynamical structures characterized by enhanced gradients of variables such as temperature or density. These structures are prominent and ubiquitous at the ocean surface and can reach particularly small scales, down to a few kilometers. They are known to play an important role in the vertical exchange of carbon, nutrients or heat between the surface and the ocean interior. Due to their small scale and short lifecycle, they have not been extensively sampled and a systematic quantification of their impact is missing. In this study, we set up a numerical simulation of the ocean circulation in the North Atlantic that resolves small‐scale fronts. We release a tracer in upper layer of the ocean and analyze how it is transported at depth. Using criteria based on the flow velocity, we quantify the fraction of the ocean surface covered by fronts. We find that the average depth at which the tracer is injected depends on the prevalence of fronts, which itself shows a strong seasonality. In winter, fronts cover less than 5% of the surface area, but contribute up to 40% of the tracer vertical transport. Conversely, in summer, fronts cover less than 1% of the area and have no significant effect on tracer vertical transport. This study helps to better understand the seasonal role of fronts in vertical water transport. This paves the way for addressing questions related to how tracers such as carbon are distributed in the world's oceans. Key Points: Surface strain and vorticity criteria can be used to identify submesoscale frontsThe tracer depth injection correlates with the surface fraction of fronts, regardless of the mixed layer depth evolutionThe submesoscale fronts contribute to ∼40% of the total tracer vertical advective subduction in winter, and less than 1% in summer [ABSTRACT FROM AUTHOR]

This study investigated the effect of severe plastic deformation induced by friction stir back extrusion on microstructure, mechanical properties, and corrosion resistance of Al-Cu-Mg alloy containing 0.5 wt.% of lithium micro-alloy and Cu/Mg ratio of 3.8. The effect of the rotational speed of friction stir back extrusion in the range of 600-1200 rpm in the constant traverse speed of 20 mm/min was studied. The results show that the size of equiaxed grains formed during the friction stir back extrusion process due to dynamic recrystallization increases from 21.0 ± 2.3 to 29.6 ± 4.5 μm by enhancing rotational speed from 800 to 1200 rpm. The dominance of the temperature effect on the plastic strain on the surface of wires during the friction stir back extrusion process results in the formation of coarser grains at the surface of wires. Friction stir back extrusion by a rotational speed of 800 rpm and a traverse speed of 20 mm/min result in the maximum yield, tensile strength, and minimum corrosion rate of 353.56 ± 10.31, 509.91 ± 11.56 MPa, and 0.008 mm/year, respectively. The friction stir back extrusion process has increased at least 23, 39, and 29% in yield strength, ultimate tensile strength, and elongation compared to as-cast alloy. [ABSTRACT FROM AUTHOR]

In this paper, uniaxial tensile testing of semi-grouted sleeve connectors was carried out by controlling the amount of expansive agent in the grout material. The effects of different steel bar diameters and anchorage depths on the failure mode, bearing capacity, and surface strain of sleeve connectors were studied. It is found that there are three failure modes in the specimens--namely, steel bar pullout failure, steel bar slip failure, and screw thread failure. The expansion characteristics of the grout material can partially compensate for the lack of compressive strength. Based on the analysis of the ultimate bearing capacity of different specimens, a design method to prevent the slip failure of the semi-grouted sleeve is proposed. The addition of 5 to 11% expansive admixture can reduce the circumferential strain of the casing from the steel bar anchorage location to the grouting end by 28.57 to 125.30%, with no impact on the longitudinal strain variation pattern. As the depth of steel bar anchorage increases, the expansive effect of the steel bar anchorage and casing longitudinal strain gradually surpasses the shrinkage effect, while the shrinkage effect at the grouting end of the casing gradually outweighs the expansive effect. With an increase in steel bar diameter, the longitudinal strain at the grouting end of the casing only decreases by 1.75% and 2.10%, essentially having no significant impact. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Co SA N C catalyst was synthesized using a seed-mediated approach and subsequently subjected to precursor pyrolysis. • Advanced characterization confirmed Co single atoms on the catalyst's surface, as well as a degree of surface strain. • The Co SA N C catalyst with appropriate strain, enhances ORR performance, leading to outstanding activity in ZABs. • Δε d could potentially function as a key descriptor for predicting the strain-dependent ORR performance in M N C catalysts. Developing efficient and cost-effective platinum-group metal-free (PGMF) catalysts for the oxygen reduction reaction (ORR) is crucial for energy conversion and storage devices. Among these catalysts, metal-nitrogen-carbon (M N C) materials, particularly cobalt single-atom catalysts (Co SA N C), show promise as ORR electrocatalysts. However, their ORR activity is often hindered by strong hydroxyl (OH) adsorption on the Co sites. While the impact of strain engineering on M N C electrocatalysts has been minimally explored, recent studies suggest its potential to enhance catalytic performance and optimize intrinsic activity in traditional bulk catalysts. In this context, we investigate the effect of surface strain on Co SA N C for ORR activity and correlate substrate-strain-induced geometric distortions with catalytic activity using experimental and theoretical methods. The findings suggest that the d -band center gap of spin states (Δε d) may be a preferred descriptor for predicting strain-dependent ORR performance in M N C catalysts. Leveraging Co SA N C moiety placed on a substrate with an average size of 1.0 μm, we achieve performance comparable to that of commercial Pt/C catalysts when used as a cathode catalyst in zinc-air batteries. This investigation unveils the structure–function relationship of M N C electrocatalysts regarding strain engineering and provides valuable insights for future ORR activity design and enhancement. [ABSTRACT FROM AUTHOR]

The S-doped PtMn concave cubes enclosed with high index facet and regulatable surface strain are successfully fabricated by two steps hydrothermal method. The PtMnS 1.1 catalyst exhibits superior catalytic properties for ethanol electrooxidation reaction in acidic and alkaline media, which is ascribed to the optimal surface strain and unsaturated surface-active sites. [Display omitted] Surface strain engineering has proven to be an efficient strategy to enhance catalytic properties of platinum (Pt)-based catalysts for electrooxidation reactions. Herein, the S-doped PtMn concave cubes (CNCs) enclosed with high index facets (HIFs) and regulatable surface strain are successfully fabricated by two steps hydrothermal method. The S element with electrophilic property can modify the near-surface of PtMn nanocrystals, altering the electronic structure of Pt to effectively regulate the adsorption/desorption of intermediates in the ethanol electrooxidation reaction (EOR). The PtMnS 1.1 catalyst with optimal surface strain delivered extraordinary catalytic performance on EOR in acidic media, with a specific activity of 2.88 mA/cm2 and mass activity of 1.10 mA/μg Pt , which is 4.1 and 2.2 times larger than that of state-of-the-art Pt/C catalyst, respectively. Additionally, the PtMnS 1.1 catalyst also achieve excellent catalytic properties in alkaline electrolyte for EOR. The results of kinetic studies indicated that the surface strain and modified electronic structure can degrade the activation energy barrier during the process of EOR, which is beneficial for enhance the reaction rate. This work provides a promising approach to construct highly efficient electrocatalysts with tunable surface strain effects for clean energy electro-chemical reactions. [ABSTRACT FROM AUTHOR]

The neutral axis concept is a fundamental and useful entity in elastic beamlike and platelike structures (where it is called the neutral surface). It distinguishes between tensile and compressive zones, governs how moments are redistributed when entering an inelastic range, and functions as a damage-sensitive attribute in condition monitoring applications. The objective of this study was to investigate the existence and characteristics of the neutral axis concept for layered elasticity—which is the most prevalent theory in the design and analysis of asphalt pavements. The investigation was done in silico by first examining the concept for an isotropic half-space, and then for two- and three-layered half-spaces. The main findings from these synthetic investigations were (1) more than one neutral surface can exist; (2) stress and strain neutral surfaces do not overlap; and (3) locations of the neutral surfaces are affected by the loading configuration. An actual case study involving Interstate 475 was examined to demonstrate the practical implications of these findings. It is concluded that all familiar/expected neutral axis characteristics deviate considerably when carried over to layered elastic theory. It is thus recommended to avoid utilizing intuition obtained from the classic neutral axis concept to interpret the mechanistic behavior of asphalt pavements. [ABSTRACT FROM AUTHOR]

The realization of nanoscale devices largely depends on our ability to control and manipulate interfacial interactions and, thus, understanding of the mechanisms of surface/interface instabilities. In this work, theoretically as well as technologically important and distinct two thermodynamic systems, which are exposed to (isobaric) and isolated from (isochoric) external body forces and surface tractions, are formulated by using irreversible thermodynamics in combination with the generalized variational method. The starting point for the present formulation closely follows up the Fowler and Guggenheim [Statistical Thermodynamics (University Press, Cambridge, 1952)] interpretation of the Planck inequality [Über Prinzip Vermehrung Entropie: Ann. Phys. Series 2(32), 462 (1887)] for isothermal reversible and irreversible (natural) infinitesimal changes in heterogeneous systems (multi-phase and multi-component). By combining this fundamental principle with the interlink between the dissipation function and global internal entropy production postulates, two distinct sets of governing equations for the surface drift-diffusion flux as well as the rate of evaporation/condensation and/or the growth/recrystallization of amorphous solid thin films are obtained for isochoric and isobaric systems. The role of Eshelby's energy-momentum tensor in the generalized potential for the interface displacement is found to differ (opposite in sign) for isochoric and isobaric systems. To demonstrate the importance of these sign conflicts, two sets of computer experiments are performed on isochoric and isobaric systems. They showed us that the elastic strain energy density contribution to the generalized driving force for surface drift-diffusion alone favoring flat and smooth surfaces in isobaric systems regardless of the sign of the uniaxial stress (healing), rather than causing the surface roughness and even catastrophic crack initiation as the case in internally strained isochoric systems. Computer simulations allowed us to track down the dynamical behavior of test modules by furnishing surface and strain energy variations, combined with the Global Helmholtz free change, which indicates the existence of two regimes: initial smooth surface undulations followed up by the rather chaotic crack formation and propagation stage at the middle of the thin film supported by the stiff substrate. In this study, we mainly focused on the development kinetics of "Stranski–Krastanow" island-type morphology, initiated by the nucleation route rather than the surface roughening scheme. The physicomathematical model, which is based on the irreversible thermodynamics treatment of surfaces and interfaces with singularities [T. O. Ogurtani, J. Chem. Phys. 124, 144706 (2006)], furnishes us to have autocontrol on otherwise free-motion of the triple junction contour line between the substrate and the droplet without presuming any equilibrium dihedral contact (wetting) angles at edges. We have also demonstrated the formation of the Stranski–Krastanow (SK)-type doublet islanding (quantum dots) as a stationary nonequilibrium state in an epitaxially strained thin flat droplet on a rigid substrate by introducing the wetting potential—invoked by the quantum confinement—into the scenario and carefully selecting the system parameters (size and shape) for the isochoric system represented by [Ge/Si (100)]. It has been also shown that on the contrary to common perceptions, the Stranski–Krastanow islands are in genuine stationary nonequilibrium states in the sense of Prigogine if one invokes proper free-moving boundary conditions at triple junctions deduced from the irreversible thermodynamics rather than ad hoc periodic or reflecting constrains at the edges. [ABSTRACT FROM AUTHOR]

In this study, near- and off-resonance Raman spectra of cadmium sulfide (CdS) quantum rods (NRs) and 4-mercaptobenzoic acid (4-MBA) adsorbed CdS NRs are reported. The envelopes of characteristic optical phonon modes in the near-resonance Raman spectrum of CdS NRs are deconvoluted by following the phonon confinement model. As compared with off-resonant Raman spectra, optical phonon modes scattering cross section is amplified significantly in near-resonance Raman spectra through the Fröhlich interaction. The Huang–Rhys factor defining the strength of the Fröhlich interaction is estimated (∼0.468). Moreover, the adsorption of different concentrations of 4-mercaptobenzoic acid (4-MBA) onto CdS NRs produces surface strain in CdS NRs originating due to surface reconstruction and consequently blue and red shifts in off-resonance (514.5 nm) Raman spectra depending on the concentration of 4-MBA. These consequences are attributed to compressive and tensile strains, respectively. Relative to bulk CdS powder as the reference, strain in CdS NRs increases with decreasing 4-MBA concentrations. In off-resonance Raman spectra of 4-MBA adsorbed CdS NRs, the full width at half maxima of phonon modes (1-LO and 2-LO) and intensity ratio I2-LO/I1-LO increase with decreasing 4-MBA concentration. [ABSTRACT FROM AUTHOR]

Highlights Carbon nanotube (CNT) film is favored in structural health monitoring of advanced composite materials, primarily due to its commendable mechanical properties and piezoresistive properties. Nonetheless, floating catalytic chemical vapor deposition (FCCVD) is an attractive method for fabrication of CNT films, and the electrical response to strain of FCCVD‐prepared CNT films is impeded by high aspect ratio and lamellar packing structure. For this purpose, FCCVD CNT films were modified by HCl dissolving Fe impurities, nano‐SiO2 particles doping and freeze‐drying in combination to increase the spacing between CNTs and its networks as well as their strain sensitivities. It showed that the gauge factor (GF) according to the variation of resistance (ΔR/R0) of the co‐modified film (CNT‐HCl‐SiO2 film) was up to 15.6 for the tensile strain at the bottom surface of unidirectional carbon fiber reinforced plastic (CFRP) laminates during the process of bending tests. The bending cycle experiment of the CFRP showed relatively stable changes of ΔR/R0 with the strains for CNT‐HCl‐SiO2 film, while that of the pristine CNT film (CNT‐HCl‐0 film) displayed unstable non‐monotonic changes and that of HCl purified CNT film (CNT‐HCl‐10 film) revealed a gradual declining tendency. Moreover, the ΔR/R0 of CNT‐HCl‐SiO2 film exhibited excellent sensitivity to the strains of multiple bistable‐deformations of cross‐ply CFRP laminates. Strain gauge analysis indicated that a 51% increase of ΔR/R0 of CNT‐HCl‐SiO2 film at the 90° layer surface corresponded to the average strain of 434 με, meanwhile a 37% increase of ΔR/R0 of the CNT film at the 0° layer surface corresponded to the strain of averagely −173.9 με, and both exhibited super high GFs of 1175 and 2108, respectively. Based on this high sensitivity, CNT‐HCl‐SiO2 film also had the ability to predict the release of residual stress during the demoulding process of CFRP. Even SiO2 dispersion in CNT film, increased the pristine film thickness by 10 times GF of CNT‐HCl‐SiO2 film increased by 68% than CNT‐HCl‐0 film and by 164% than CNT‐HCl‐10 film SiO2 doping significantly improved the stability of the CNT film's ΔR/R0 with temperature and strain CNT‐HCl‐SiO2 film has the ability to monitor the deformation and residual stress of CFRP [ABSTRACT FROM AUTHOR]

We report a novel one‐second strategy for the surface treatment of conventional graphite electrodes for the electrochemical detection of valrubicin, a potent chemotherapeutic agent used intravesically for the treatment of bladder cancer. The surface graphenization process enhances the surface area of the electrode and introduces surface defects and strain that increase its electrocatalytic activity and provides fast charge transfer pathways for an efficient redox process with excellent stability due to the direct connection with the core graphite electrode. The surface graphenized electrode is characterized using electron microscopy and Raman spectroscopy, and its electrochemical properties are studied using cyclic voltammetry and electrochemical impedance spectroscopy. A voltammetric method is developed for valrubicin detection using the surface graphenized electrode, optimized, and the electrochemical reduction mechanism is elucidated. A calibration curve is established with a wide linear range of 0.02–3 μM and a low limit of detection of 26.9 nM. Excellent reproducibility and stability are displayed and the clinical validity is demonstrated by analyzing valrubicin in human serum, achieving a high recovery of ≈90 %. The high performance and excellent sensitivity of the developed electrode show the significant impact of the surface graphenization strategy for further application in electrochemical sensing. [ABSTRACT FROM AUTHOR]

Alkali silica reaction (ASR) is an undesirable phenomenon that occurs between alkalis that usually originate from cement and certain types of siliceous aggregates in concrete. The result of this reaction is delayed expansion of hardened concrete in the presence of moisture, which may cause cracking and damage in an existing structure. The present paper investigates the general behavior and shear strength of pretensioned concrete bridge girders affected by ASR. Four identical pretensioned concrete AASHTO Type I girders were fabricated using reactive concrete and subjected to environmental conditioning at a relative humidity of 100% and a temperature of 45 degrees Celsius for up to 296 days to accelerate the development of ASR. During this period, ASR‐induced expansions, changes in surface strains of concrete, transfer lengths, and patterns of damage and cracking were monitored. Each specimen was subjected to shear‐critical loading until failure upon reaching the desired expansion level. The results showed that the existence of prestressing force played a significant role in limiting the ASR‐induced in‐plane expansion and cracking. Progress of ASR caused a reduction in the load corresponding to the first detected flexural crack but an increase by up to 14% in the load corresponding to the first diagonal cracking compared to the control specimen, likely due to the additional prestress caused by restrained ASR‐induced expansions. The ultimate shear strength of ASR‐affected girders was generally within 5% of the control specimens, and all specimens exceeded their nominal shear strengths according to AASHTO LRFD 2020 specifications. Until the unrestrained uniaxial expansion of 0.2%, no significant concerns were identified regarding the shear strength of the ASR‐affected pretensioned concrete specimens. [ABSTRACT FROM AUTHOR]

In typical reinforced concrete design, reinforcement is designed to carry axial forces, but it can also resist transversal forces by dowel action. This is usually neglected for simplicity's sake in the design phase, but it can be accounted for either explicitly in mechanical models or implicitly in empirical relationships. Furthermore, there are cases where the connection between various concrete elements explicitly depends on dowel action, as for example, in connections between precast elements or between two concrete parts cast at different times. On the other side, dowel action can have a negative impact on the fatigue resistance of reinforcing bars subjected to cyclic loading, because of the local stress concentrations near interfaces due to relative movements, either in sliding or in opening of cracks not perpendicular to the bar. For the assessment of the remaining capacity of existing structures, improved models of the behavior are needed, including realistic models of the behavior of concrete, steel and their interfaces. The aim of the present paper is to provide a contribution to a better understanding of dowel action by two test series. The first series focused on the behavior of the dowel: the concrete specimens with the embedded bars were placed in a custom‐made test setup and subjected to monotonic or low stress‐level cyclic actions with a longitudinal and a transversal crack opening component, up to developing the full plastic capacity of the dowel and rupture at the peak of catenary action. The measurement system included tracking the displacement field at the surface of the concrete and the strains in the dowel by optical fibers glued on its surface. The latter measurements allow to derive the internal forces in the reinforcing bar and deformed shape of the bar as well as the contact pressure between the bar and the surrounding concrete. The results show a strong dependency on the test variables: diameter of the bar, imposed crack kinematics and angle between the bar and the crack. The second test series looked more closely at the behavior of concrete underneath the bar, in the presence of a point load introduced at various locations into concrete through a reinforcing bar. A comparison of the test results with existing models shows a general good agreement and some aspects that deserve to be improved. [ABSTRACT FROM AUTHOR]

The crustal material from central Tibet is extruded in a clockwise direction along a belt on the eastern plateau. In the inner arc region of the escaping belt, the absence of key and detailed 3‐D crustal resistivity structure hinders a comprehensive understanding of the dynamic processes of material escape in both the inner and outer arc regions. Here, we conducted magnetotelluric imaging and obtained the crustal 3‐D resistivity structure in Sanjiang area. The results reveal the presence of two branched high‐conductivity anomaly belts in the middle crust. Combining with other resistivity and velocity models, we speculated that crustal flow is widely distributed in the middle crust of the Chuan‐Dian block. The crustal flow in the Sanjiang area may connect to that in the outer arc region. The crustal flow in the eastern part is extensively continuous, causing decoupling and flowing that facilitate intense horizontal movements and deformation of the upper crust. In the western Sanjiang area, the upper crust is strongly coupled with the lithosphere beneath the decoupling layer, resulting in weaker horizontal deformation, and fewer larger earthquakes. The initially weak crustal zone in the eastern Tibet may have been caused by uplift of hot mantle material. The high heat flow associated with uplift of hot mantle material and the frictional heating caused by the horizontal movement of weakly coupled crust further facilitated the formation of crustal flow in the outer arc region. The branched crustal flow in the Sanjiang area may have flowed from the outer arc region of the escaping belt. Plain Language Summary: The crustal flow model can well explain the expansion of the Tibetan Plateau in the eastern margin of the plateau, and the high‐conductivity bodies in the middle‐lower crust may reflect the morphology of crustal flow. In the Sanjiang area of eastern Tibet, we used magnetotelluric data from 41 sites to discover branched high‐conductivity belts in the middle crust through 3‐D imaging, which are different from the extensively continuous high‐conductivity layer in the eastern part. They reveal the differences in the morphology of crustal flow between the inner and outer arc regions of the material escaping belt. The difference in the morphology of high‐conductivity structures leads to different degrees of crustal mechanical coupling, which in turn is related to surface strain rate, topography, and seismic activities. We speculate that crustal flow initially originated from the outer arc region and gradually developed toward the inner arc region. Key Points: 3‐D magnetotelluric imaging confirmed the presence of branched crustal flow in Sanjiang area, eastern Tibetan PlateauCrustal flow is widely in the middle crust of the North Chuan‐Dian block and its morphologies in eastern and western are differentThe branched crustal flow in the Sanjiang area may have flowed from the outer arc region of the escaping belt [ABSTRACT FROM AUTHOR]

The low delamination tendency and high damage tolerance of three-dimensional (3D) braided composites highlight their significant potential in handling defects. To enhance the engineering potential of three-dimensional four-directional (3D4d) braided composites and assess the failure mode of hole defects, this study introduces a series of 3D4d braided composites with prefabricated holes, studying their compressive properties and failure mechanisms through experimental and finite element methods. Digital image correlation (DIC) was used to monitor the compressive strain on the surface of materials. Scanning acoustic microscope (SAM) and scanning electron microscopy (SEM) were used to characterize the longitudinal compression failure mode inside the material. A macroscopic model is established, and the porous materials are predicted by using the general braided composite material prediction theory. While reducing the forecast cost, the error is also controlled within 21%. The analysis of failure mechanisms elucidates the damage extension mode, and the porous damage tolerance ability aligns closely with the bearing mode of braided material structure. Different braiding angles will lead to different bearing modes of materials. Under longitudinal compression, the average strength loss of 15° specimens is 38.21%, and that of 30° specimens is 8.1%. The larger the braided angle, the stronger the porous damage tolerance. Different types of prefabricated holes will also affect their mechanical properties and damage tolerance. [ABSTRACT FROM AUTHOR]

In this study, the crystal plasticity finite element method was established by coupling the crystal plasticity and finite element method (FEM). The effect of rolling deformation and slip system of polycrystalline Al-Mg-Si aluminum alloy was investigated. The results showed that there was a pronounced heterogeneity in the stress and strain distribution of the material during cold rolling. The maximum strain and shear strain occurred at surface of the material. The smaller the grain size, the lower the strain concentration at the grain boundary. Meanwhile, a smaller strain difference existed between the grain interior and near the boundary. The rotation of grains leads to significant differences in deformation and rotation depending on their initial orientations during the rolling process. The slip system of (11-1)<-110> had a large effect on the plastic deformation, (111)<10-1> is second, and the effect of (1-11)<011> slip system on the plastic deformation is the smallest. After deformation, the grain orientation concentration was increased with deformation. Therefore, both the strength and volume fraction of texture were increased with the increase in rolling deformation. The experimental results of EBSD indicated that the large rolling reduction resulted in severe grain twisting, so the texture strength was increased. The simulation results were in close agreement with the experimental results. This study provides a theoretical basis for the rolling process, microstructure, and performance control of aluminum alloys. [ABSTRACT FROM AUTHOR]

We combined novel laboratory techniques and numerical modeling to investigate (a)seismic preparatory processes associated with deformation localization during a triaxial failure test on a dry sample of Berea sandstone. Laboratory observations were quantified by measuring strain localization on the sample surface with a distributed strain sensing (DSS) array, utilizing optical fibers, in conjunction with both passive and active acoustic emission (AE) techniques. A physics-based computational model was subsequently employed to understand the underlying physics of these observations and to establish a spatio-temporal correlation between the laboratory and modeling results. These simulations revealed three distinct stages of preparatory processes: (i) highly dissipative fronts propagated towards the middle of the sample correlating with the observed acoustic emission locations; (ii) dissipative regions were individuated in the middle of the sample and could be linked to a discernible decrease of the P-wave velocities; (iii) a system of conjugate bands formed, coalesced into a single band that grew from the center towards the sample surface and was interpreted to be representative for the preparation of a weak plane. Dilatative lobes at the process zones of the weak plane extended outwards and grew to the surface, causing strain localization and an acceleration of the simulated deformation prior to failure. This was also observed during the experiment with the strain rate measurements and spatio-temporally correlated with an increase of the seismicity rate in a similar rock volume. The combined approach of such laboratory and numerical techniques provides an enriched view of (a)seismic preparatory processes preceding the mainshock. Highlights: The combination of novel laboratory and numerical techniques allowed us to detect preparatory processes prior to failure. The employment of distributed strain sensing with optical fibers was successful in imaging strain localization preceding failure. The simulated dissipation of mechanical energy correlated with the observations of strain localization occurring during the experiment. [ABSTRACT FROM AUTHOR]

Sheet metals subjected to biaxial plane stress loading typically fail due to localized necking in the thickness direction. Classical plasticity models using a smooth yield surface and the normality flow rule cannot predict localized necking at realistic strain levels when both the in-plane principal strains are tensile. In this paper, a recently developed multi-surface model for porous metal plasticity is used to show that the development of vertices on the yield surface at finite strains due to microscopic void growth, and the resulting deviations from plastic flow normality, can result in realistic predictions for the limit strains under biaxial tensile loadings. The shapes of the forming limit curves predicted using an instability analysis are in qualitative agreement with experiments. The effect of constitutive features such as strain hardening and void nucleation on the predicted ductility are discussed. [ABSTRACT FROM AUTHOR]

Shape sensing refers to the deformation reconstruction of structures using measured surface strain. However, there is currently a lack of research on the shape sensing of large deformations, especially for beam structures. To address this issue, this paper proposes a new method called the rotation angle approximation (RAA) for reconstructing large deformations of beam structures. This method utilizes theoretical and actual curvatures to create a least-squares error functional. By minimizing this functional, the rotation angles of the corresponding beam can be obtained, avoiding the accumulation of errors that occurs when using traditional computation methods. The deformed shapes can be predicted utilizing the boundary conditions and the rotation angles along the beam. This method can reconstruct the large deformation of a beam without requiring prior knowledge about the material properties or external loads. The accuracy and effectiveness of this method were validated through numerical simulations and experiments. The results indicate that this method can accurately predict the different deformations of a beam induced by various loading conditions. [ABSTRACT FROM AUTHOR]

Herein, the detailed corrosion behavior of ultrafast laser‐surface structured Ti6Al4V (using a Ti: Sapphire laser processed under optimum parameters) is carried out in simulated body fluid using electrochemical impedance spectroscopy and correlated with surface characteristics. Laser structuring leads to a topographically modified surface consisting of periodic surface patterns (nanoripples, nanodots) in the presence of a thin oxide layer. Surface processing introduces strain on the surface up to a depth of 150 μm, with the grains aligned along the (101¯0)$\left(\right. 10 \bar{1} 0 \left.\right)$ and (21¯1¯0)$\left(\right. 2 \bar{1} \bar{1} 0 \left.\right)$ planes. The detailed electrochemical impedance spectroscopic studies show the formation of stable passive layers in surface‐structured Ti6Al4V as compared to as‐received Ti6Al4V. [ABSTRACT FROM AUTHOR]

Wearable technology excels in estimating kinematic and physiological data, but estimating biological torques remains an open challenge. Deformation of the skin above contracting muscles—surface‐level muscle deformation—has emerged as a promising signal for joint torque estimation. However, a lack of ground‐truth measures of surface‐level muscle deformation has complicated the evaluation of wearable sensors designed to measure surface‐level muscle deformation. A non‐contact methodology is proposed for ground‐truth measurement of surface‐level muscle deformation using a 2D laser profilometer. It shows how three metrics of surface‐level muscle deformation—peak radial displacement: r = 0.94 ± 0.05, surface curvature: r= 0.78 ± 0.10, surface strain: r = 0.83 ± 0.12—correlate strongly to changes in volitional elbow torque, further exploring the impact of measurement location or joint angle on these relationships. A nonlinear, lead‐lag relationship between surface‐level muscle deformation and torque is also found. The findings suggest that surface‐level muscle deformation is a promising signal for non‐invasive, real‐time estimates of torque. By standardizing measurement, the methodology can help inform the design of future wearable sensors. [ABSTRACT FROM AUTHOR]

The performance and operational stability of perovskite‐based devices heavily rely on the interfacial properties between the photoactive perovskite layer and charge transport layers. Understanding the theoretical relationship between surface/interface dipoles and surface energetics is crucial for scientific understanding and practical applications. In this study, a method is applied that bridges classical electromagnetism and modern atomistic approaches. The impact of dipolar ligand molecules functionalizing the FASnI3 perovskite surface is investigated, with inspection of the interplay between surface dipole, charge transfer, and local strain effect, and corresponding shifts in the valence level. The results reveal that the contribution of individual molecular entities to surface dipoles and electric susceptibilities follows an essentially additive behavior. The influence of F doping usually used to mitigate Sn oxidation in Sn‐based layer for photovoltaic applications, is also discussed. Furthermore, the findings are compared with predictions from classical approaches employing a capacitor model that links the induced vacuum level shift and the molecular dipole moment. The insights gained from the study provide theoretical guidelines for fine‐tuning the work functions of materials, thus enabling effective interfacial engineering in this class of semiconductors. [ABSTRACT FROM AUTHOR]

The investigation of strain hardening in metals is complex, with the outcome depending on experimental conditions, that may involve microstructural history, temperature and loading rate. Hardening is commonly measured, after mechanical processing, through controlled mechanical testing, in ways that either distinguish elastic (stress) from total deformation measurements, or by identifying plastic slip contributions. In this paper, we conjecture that hardening effects can be unraveled through statistical analysis of total strain fluctuations during the evolution sequence of profiles, measured in-situ, through digital image correlation. In particular, we hypothesize that the work hardening exponent is related, through a power-law relationship, to a particular exponent arising from principal component analysis. We demonstrate a scaling analysis for synthetic data produced by widely applicable crystal plasticity models for polycrystalline solids. [ABSTRACT FROM AUTHOR]