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Distributed acoustic sensing (DAS) using fiber-optic cables has potential for landslide and rockfall monitoring along linear infrastructure but faces challenges for accurate seismic source localization due to signal nonuniformity and attenuation during propagation. This limits the applicability of traditional seismic location methods with DAS. We present a novel computer vision–based approach to overcome these limitations. Field experiments simulating landslide quakes and rockfall impacts were conducted near dedicated DAS arrays to validate the method. Results demonstrate the computer vision technique outperforms short-to-long-term average ratio and cross-correlation algorithms in both location accuracy and constraint of seismic sources, with locations also agreeing well with a colocated nodal seismic array. Key factors influencing performance include the type of signal processing used on the DAS data and cable array geometry. The envelope function best handled noise while L-shape and parallel dual-cable geometries proved most effective. Overall, this computer vision method provides an improved solution for seismic source location of landslides and rockfalls monitored by DAS networks, enhancing safety along vulnerable linear infrastructure like transportation corridors through mountainous terrain. [ABSTRACT FROM AUTHOR]

Iron in soil exists in various valence states and is prone to changes with alterations in soil environmental conditions. Its migration and transformation are crucial for soil formation and understanding soil evolution. This study focuses on Quaternary red soils found in woodland, sparse forest grassland, grassland, and cultivated land located in the semi-humid region of the middle temperate zone. For comparison, buried Quaternary red soil was also examined. A soil reconstruction model was used to quantitatively calculate the variation of different forms of iron in order to analyze various forms of iron composition, migration, and transformation within the soil profile, as well as the evolutionary traits of Quaternary red soils influenced by diverse land use activities. This study found that after exposure and use, iron from the topsoil of buried Quaternary red soil migrated to the subsoil, altering the iron distribution. Free iron and crystalline oxides decreased in the topsoil but increased in specific subsoil layers, with woodland and grassland showing the most significant changes. Silicate-bound iron pooled in the soil weathered to form free iron under different land uses, and poorly crystalline iron oxides transformed into crystalline oxides, with grassland exhibiting the highest transformation intensity. Conversion processes predominated over iron migration in the Quaternary red soils. The evolution of Quaternary red soils can be divided into three stages, marked by changes in iron composition and crystallization due to anthropogenic land use activities. Initially, during 140−94 ka BP, iron composition was stable. Then, between 94–24 ka BP, plant decomposition formed iron–metal complexes, releasing and crystallizing poorly crystalline iron oxides. Finally, from 24 ka BP to the present, anthropogenic activities intensified, increasing the formation and conversion rates of these oxides. This study quantifies iron migration and transformation in Quaternary red soils, providing insights for sustainable soil management, especially in regions where human activities have accelerated iron evolution. Based on these findings, the following policy recommendations are proposed: implement sustainable land use practices, encourage land management strategies that preserve natural vegetation, promote research on soil management techniques, develop and implement regulatory policies, and support educational programs to maintain the health and stability of Quaternary red soils, particularly in regions prone to accelerated iron evolution due to anthropogenic activities. [ABSTRACT FROM AUTHOR]

This document, titled "Climate Change and Agriculture—Sustainable Plant Production," discusses the impact of climate change on plant growth and agricultural production. It highlights how climate change can affect the growing season, growth rate, and distribution of plants. While climate change can extend the growing season and promote crop photosynthesis, it can also lead to imbalanced nutrient absorption, hinder photosynthesis, and affect crop yields. Irregular precipitation patterns and extreme weather events can cause hypoxia and nutrient loss in plant roots, damage plants directly, and increase the range of diseases and pests. Climate change also affects soil moisture, temperature, microbial activity, nutrient cycling, and quality, which in turn affects plant growth. The document emphasizes the importance of understanding the mechanisms through which climate change impacts plants and agriculture and taking adaptive measures to promote sustainable agricultural development. The document also introduces a special issue of the journal Agronomy, which focuses on the interaction between climate change and agriculture and includes research on crops, soils, and adaptation strategies. The research covers topics such as the impact of temperature/climate change on rice, wheat, and olive oil; the adaptation strategies of crops; the impact of climate change on soil nutrient cycling; and the spatial-temporal characteristics of vegetation. The document provides summaries of some of the articles included in the special issue, which discuss topics such as the stoichiometric relationship of soil nutrients, the impact of climate warming and aridification on vegetation, the impact of heat stress on rice growth, the physiological characteristics [Extracted from the article]

River deltas, where ocean tides can often freely propagate into the river, are focal points of human settlement. Beneath the delta surface, groundwater stored in the soil strata fluctuates with river tides, resulting in pressure variations within the soil strata. Here, we introduce a novel ultra‐weak fiber‐optic instrument to test the hypothesis that tide‐induced groundwater level variations induce periodic soil stratum deformation. Using borehole deployments ranging over 70 m in the subsurface of the Yangtze Delta, we observe semidiurnal and spring–neap cycles of soil stratum deformation and reveal its dependence on lithology and depth. This allows us to coin the new term "soil stratum tide," defined as the periodic deformation of soil strata in response to pressure fluctuations induced by tides in open water. High‐accuracy monitoring of the breathing of tidal deltas enables calibrating Earth observation systems, analysis of delta subsidence, and safeguarding of infrastructure jeopardized by soil stratum deformation. Plain Language Summary: River deltas are important population centers, and deformation of their subsurface endangers the safety of nearly half a billion people worldwide. In tidal deltas, groundwater stored in soil strata fluctuates with river tides, resulting in pressure changes within the soil strata. Whether these pressure variations translate into expansion–shrinking cycles of the soil strata remains unknown to date. We break new ground in this field by developing a fiber‐optic instrument with microstrain accuracy and meter‐scale resolution. Using this novel sensing approach, we observe tidal soil stratum deformations beneath the Yangtze Delta and evaluate their dependence on lithology and depth. We coin the new term "soil stratum tide", and pave the way for high‐accuracy deformation monitoring of the shallow subsurface of river deltas. Key Points: We develop a novel quasidistributed ultra‐weak fiber Bragg grating instrument to observe and measure subtle subsurface deformationOur monitoring data provide the first view on soil stratum tidal deformation to dateThe energy of soil stratum tides is dominantly controlled by subsoil stiffness, permeability, and pore pressure tidal amplitude [ABSTRACT FROM AUTHOR]

Immunosuppressive myeloid cells in the tumor microenvironment inhibit anti-tumor immunity and support tumor development. The leukocyte Ig-like receptor subfamily B (LILRB) proteins and the related receptor LAIR1 are immune checkpoint receptors that support the immunosuppressive activity of myeloid cells. All LILRBs and LAIR1 have intracellular immunoreceptor tyrosine-based inhibitory motifs in their signaling domains, but the individual proteins have different functions. The determinants of the distinct functions of these inhibitory receptors likely rest in their interactions with different ligands and other surface proteins, characteristic signaling domains, and expression dynamics in different cell types regulated by various extrinsic cues and transcription factors. Significant advancement of immuno-oncology therapeutic products based on targeting or reprogramming of LILRB- and LAIR1-mediated signaling is anticipated. [ABSTRACT FROM AUTHOR]

• Abnormal synaptic plasticity and synaptic homeostasis imbalance in depression. • Aberrant presynaptic SNARE-mediated vesicle release affects synaptic transmission. • Postsynaptic related pathways response to synaptic transmission regulates depression. Depressive disorder is the leading cause of disability worldwide, yet the mechanisms underlying depression are not fully understood. Vesicle release is essential for synaptic neurotransmission, the abnormalities of vesicle release and synaptic plasticity are associated with various neuropsychiatric disorders. Neural circuits are ensembles of interconnected neurons that collectively perform specific functions. To some extent, depression may be caused by a disruption in the structural and functional connections of the neural circuits underlying emotion regulation. In this review, we summarized the role of abnormalities of vesicle release and synaptic transmission, as well as the related regulatory molecules and signal pathways in the regulation of depression. [ABSTRACT FROM AUTHOR]

Accurately predicting the stress distribution around the tunnel is crucial for designing safe and economical support systems. The stress distribution is closely related to the ground stress release induced by tunneling, as well as the initial gravity stress and boundary conditions. In this study, a two-dimensional analytical model considering the ground surface boundary conditions and gravity is presented to investigate the stress field around the tunnel. Then, a numerical model was developed to validate the proposed analytical model. Finally, parametric analyses were conducted, and the limitations of the load calculation method of the code for design of shield tunnel in China were discussed. The results indicate that: (a) Tunnel excavation induces stress redistribution in the soil, resulting in a soil arching effect around the tunnel. This arching effect causes nonlinear load changes around the tunnel. (b) The soil mass around the tunnel can be divided into undisturbed and disturbed zones. Above the tunnel, the disturbance range is C -2 D (C and D represent the burial depth and the tunnel diameter), while below and on both sides of the tunnel, the disturbance ranges are 4 D and 1.5 D , respectively. (c) Once the stress release rate reaches 0.6, a combined arching effect zone, consisting of both major and minor principal stresses, is formed in the disturbance zone above and below the tunnel. (d) The load distribution pattern calculated by the code for design of shield tunnel in China is gourd-shaped, and this calculation method is insufficient for accurately evaluating the load around the tunnel. The research results can provide a reference for the design of the shield tunnel. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: To better understand the impact of different anions on the structures and SCO properties of the CoII SCO complexes, six new complexes [Co(terpy‐CH2OH)2]A2·sol (terpy‐CH2OH = 4′‐(hydroxymethyl)‐2,2′;6′,2″‐terpyridine, A = Br– (1, sol = 1.5H2O), I– (2), N3– (3, sol = 2H2O), H3BCN– (4), OTf– (5), and TsO– (6, sol = 4H2O·CH3CN), have been synthesized and characterized. All six compounds consist of mononuclear [Co(terpy‐CH2OH)2]2+ cations and charge‐balancing anions that differ in size, shape, and hydrogen bonding capacity. Complexes 1, 2, 3, and 6 displayed incomplete gradual SCO transitions, whereas 4 and 5 exhibited abrupt hysteretic spin transitions with loops of 12 and 16 K (250.0—262.0 K for 4, and 370.0—386.0 K for 5, respectively), closely resembling our previously reported complexes with SCN– and SeCN– anions. The occurrence of the order‐disorder transition of the CH2OH groups and their transition temperatures are determined by the size and hydrogen bonding capability of the anions. Remarkably, the transition temperatures of complexes with H3BCN–, SCN–, OTf–, and SeCN– anions exhibit an upward trend as the size and mass of the anions increase, as confirmed through detailed single crystal structure analyses conducted in both high‐spin and low‐spin states for all four complexes. [ABSTRACT FROM AUTHOR]

The inspection of broken wires in prestressed concrete cylinder pipes is crucial for ensuring the safety and reliability of the pipeline. Traditional point detection techniques always require labor-intensive periodic inspections and cannot deployed along the entire pipeline, significantly limiting the development of the industry. Hence, there is an urgent need for more advanced and intelligent sensors that can achieve 100% coverage and provide sufficient accuracy assurance. In this work, we develop a distributed acoustic sensing -based automated monitoring system to accurately classify the rupture of prestressed wires. First, a computer vision approach is employed to primarily screen out potential vibrational signals from DAS array images. Then, a pre-trained support vector machine model is used to classify the vibrations as either wire breakages or non-wire breakages. This model's performance surpassed other classification strategies, achieving 99.62% accuracy, 99.41% precision, 98.82% recall, and 99.12% F1-score in a side-to-side comparison. Our innovative workflow provides a comprehensive solution for detecting broken wires and offers guidance for the application of artificial intelligence-based DAS to complex vibration systems with limited training data. [ABSTRACT FROM AUTHOR]

Vertical deformation profiles of subterranean geological formations are conventionally measured by borehole extensometry. Distributed strain sensing (DSS) paired with fiber-optic cables installed in the ground opens up possibilities for acquiring high-resolution static and quasistatic strain profiles of deforming strata, but it is currently limited by reduced data quality due to complicated patterns of interaction between the buried cables and their surroundings, especially in upper soil layers under low confining pressures. Extending recent DSS studies, we present an improved approach using microanchored fiber-optic cables—designed to optimize ground-to-cable coupling at the near surface—for strain determination along entire lengths of vertical boreholes. We proposed a novel criterion for soil–cable coupling evaluation based on the geotechnical bearing capacity theory. We applied this enhanced methodology to monitor groundwater-related vertical motions in both laboratory and field experiments. Corroborating extensometer recordings, acquired simultaneously, validated fiber optically determined displacements, suggesting microanchored DSS as an improved means for detecting and monitoring shallow subsurface strain profiles. [ABSTRACT FROM AUTHOR]

Fiber‐optic sensing is emerging as a superior means for distributed strain sensing of the subsurface. The ability of an embedded fiber‐optic cable to capture accurate strain profiles depends on the degree of rigid mechanical coupling between the ground and the cable. However, a current challenge in this field is to determine the actual level of ground deformation from strain signatures sensed by the cable deployed in the subsurface; addressing this issue has been hampered by the lack of suitable theoretical methods. Here we propose a two‐step ground‐cable coupling evaluation procedure, whereby we develop analytical formulations to quantify the interaction and interface shear transfer of a ground‐borehole‐cable system. We constrain key model parameters using a data set acquired with a fiber optics‐instrumented borehole for monitoring groundwater‐related sediment compaction. Extensive parametric analyses reveal that increasing the backfill modulus and cable gauge length or decreasing the borehole radius and cable stiffness can improve the quality of strain transferred to the cable from the ground; the effect of ground properties is comparably insignificant. Further, we develop design charts and tables at designated transfer thresholds to facilitate the development and field deployment of fiber sensing elements. Taken together, the theoretical quantification of ground‐cable coupling should improve the state‐of‐the‐art performance of distributed fiber‐optic strain sensing for subsurface ground movements detection and monitoring. Key Points: A new definition of ground‐cable coupling allows determining actual levels of ground deformation from fiber‐optic (FO) strain measurementsExtensive parametric analyses reveal effects of ground, borehole, backfill, and cable properties on ground‐to‐cable strain transfer qualityWe develop design charts and tables at designated transfer thresholds to facilitate FO instrumentation development and field deployment [ABSTRACT FROM AUTHOR]

• DAS enables long-distance wastewater monitoring via flow-induced fiber vibrations. • DAS distinguishes river background noise and turbulent discharge plume vibrations. • Vibrational power analysis locates outfalls with meter precision. • Time–frequency processing resolves discharge timing and properties at high resolution. • Frequency centroid presents potential for automated identification. Wastewater discharge from outfall pipes can significantly impact river water quality and aquatic ecosystems. Effective outfall monitoring is critical for controlling pollution and protecting public health. This study demonstrates a novel distributed acoustic sensing (DAS) approach for detecting wastewater discharge events from outfall pipes located along rivers. Controlled field experiments were conducted in an industrial park river to systematically evaluate DAS performance. DAS detects vibrational signals imparted to suspended fiber-optic cables by turbulent wastewater flows, predominantly within 10–30 Hz, enabling continuous monitoring along entire river lengths. Vibrational power analysis locates outfalls with meter-level accuracy, while time–frequency techniques discern discharge timing and characteristics. Cable type and outfall–fiber separation influence on detection capability was assessed. Thermoplastic-jacketed tight buffer cables optimized detection through enhanced vibrational coupling. Vibrational energy decreased exponentially with separation, highlighting benefits of proximal deployment for sensitivity. However, detection range scales with discharge flow rate. Frequency centroid proved a robust feature with potential for automated discharge identification. Overall, DAS enables high spatiotemporal resolution monitoring to pinpoint concealed outfalls minimally invasively. This positions DAS as a promising tool supporting improved water governance through early pollution warnings and rapid source localization via outfall vibrational signatures emanating across river networks. [Display omitted] [ABSTRACT FROM AUTHOR]

• Demonstrated fiber-optic DAS for pinhole leak detection in buried gas pipelines. • Described soil morphological changes (cavities, uplift, fissures) induced by leakage. • Identified two signal sources: dynamic soil straining, gas–fiber friction. • Examined impacts of factors on DAS detection performance. Detecting pinhole leaks in long-haul buried gas pipelines is challenging due to weak leak signals and large spans. Fiber-optic distributed acoustic sensing (DAS) technology offers highly sensitive long-distance monitoring. This study evaluates DAS for detecting pinhole gas leaks in pipelines buried in sandy soil. Controlled experiments examined the effects of pipe-to-fiber distance, fiber position, leak direction, gas pressure, and leak diameter. Pressurized gas erodes the overlying soil, forming cavities and fissures that change soil morphology. Gas preferentially diffuses upward; an optical fiber above the pipe has the highest sensitivity regardless of leak direction and should be deployed above pipelines. Two mechanisms produce DAS-recorded leak vibration signals: dynamic soil straining and gas–fiber friction. Vibration energy from dynamic soil motion concentrates at 60–120 Hz while gas–fiber friction exhibits a broader spectral response. Increasing gas pressure or leak diameter increases detected vibration power but decreases peak frequency and proportion generated by soil strain, indicating a shift toward gas–fiber friction as the dominant mechanism. These results inform improved pinhole leak monitoring in buried gas pipelines using DAS technology. [ABSTRACT FROM AUTHOR]

• An analytical model of the segment longitudinal joints considering different arrangements of double sealing gaskets. • The effect of the arrangement of sealing gaskets on the mechanical behavior of segment longitudinal joints. • The arrangement of double sealing gaskets and the location of bolts in the large-diameter shield tunnel. The sealing gasket of the traditional double waterproof system of the large diameter shield tunnel consists of two sealing gaskets which are arranged on the outside of the bolt hole(SGOH) or arranged on both sides of the bolt hole(SGBH). The different arrangement of the double sealing gaskets has significant effects on the mechanical behaviors of the longitudinal joints of the segment. In this paper, based on the energy equivalence principle, the actual distribution stress of the compression zone of the segment longitudinal joints was simplified equivalently as rectangular distribution stress. Then, a progressive mechanical model was established for the longitudinal joint, taking into account the effect of double sealing gaskets arrangements. Furthermore, the proposed mechanical model was validated through former experimental results and other analytical models. Finally, the effect of different arrangements of the double sealing gaskets on the mechanical behavior of the longitudinal joints of the segment was compared and analyzed. The results showed that the difference in the arrangement of the double sealing gaskets results in varying effects of the additional bending moment on the joint bending deformation under sagging and hogging moments, leading to the unequal bending stiffness of the joint. The difference in bending stiffness caused by the double sealing gasket arrangements is approximately 100∼150 MN·m/rad. To optimize the mechanical behaviors of the joints, the double sealing gaskets should be arranged on both sides of the bolt hole(SGBH), with the bolt located at the center of both the longitudinal joints and the core compressive zone of the longitudinal joints. [ABSTRACT FROM AUTHOR]

Distributed acoustic sensing (DAS) using fiber-optic cables shows promise for rockfall monitoring by potentially offering high spatial resolution and wide coverage at lower costs. However, further research is needed to fully evaluate DAS performance for rockfall applications. This study assesses DAS capabilities for rockfall monitoring by analyzing DAS and seismometer recordings of 38 artificially triggered rockfalls with block masses ranging from 139.6 to 638 kg. Results demonstrate strong correlations between DAS waveforms and spectra with colocated seismometers, validating DAS data for detecting rockfall impacts. Fiber configuration impacted DAS sensitivity: fully in-contact cables improved signal-to-noise ratios and detection of high frequencies from 55 to 86 Hz. Analyses of seismic waves identified three distinct rock block propagation modes associated with intact, fragmenting, and collapse-triggering movements. While DAS signal feature values agreed with seismometers, no clear mass correlation emerged within the examined range. However, spectral features like frequency centroid (48.8 ± 6.5 Hz) and predominant frequency (41.0 ± 12.1 Hz) exhibited spatial stability across channels, indicating potential for event identification. Preliminary attempts to locate rockfall sources from DAS arrays proved feasible but require optimization. Overall, enhanced fiber coupling, identification of propagation modes, spatially-dependent analyses, and dense-array source location may enable DAS to complement sparse seismic networks for higher resolution, cost-effective rockfall monitoring. These insights could inform the development of improved rockfall monitoring strategies leveraging distributed fiber-optic sensing. • DAS signals match colocated seismometers, validating impact detection. • Fully coupled fiber improves DAS sensitivity/high-frequency detection up to 86 Hz. • Three distinct rock block propagation modes identified, linked to movements. • DAS spectral features spatially stable, indicating event identification potential. • Preliminary dense-array source location using DAS demonstrates feasibility. [ABSTRACT FROM AUTHOR]

Abstract This paper was concerned with an approach to predict fatigue life based on a multi-scale crack propagation model. The expressions of crack propagation rates in microstructurally small crack (MSC), physically small crack (PSC) and long crack (LC) stages were unified in the multi-scale crack propagation model. Its integral form presented a fatigue life prediction approach. The nickel-based GH4169 alloy was employed to validate the prediction capacity of present approach. The prediction results of lives of specimens with different initial defects sizes were compared with the experimental data. [ABSTRACT FROM AUTHOR]

The coarse segregative eutectic phases, emerged in the twin roll casting (TRC) process of Mg strips, which cannot be resolved solely by controlling the processing variables or post heat treatment, are detrimental to the subsequent rolling deformation. Considering it, we introduce the pre-rolling steps on the TRC Mg-4Al-2Sn-1Zn (ATZ421) alloys, which is expected to facilitate the dissolution of these segregative phases by increasing distortion of crystal lattices and rolling stress, and further investigate the effect of a single pass or two passes pre-rolling on the microstructure evolution and tensile properties. It indicates that the pre-rolled alloy with two passes presents more uniform precipitates and higher twinning density in comparison with that using a single pass. The uniform distribution of precipitates in two passes pre-rolling is due to the increase in density of dislocations and deformed twins, which results in more distortion of crystal lattices with more stored energy, facilitating the diffusion of solutes. Moreover, the pre-rolling of two passes introduces more rolling stress into Mg matrix, which is beneficial for the crush of coarse eutectic phases, and further accelerates the sufficient dissolution of second phases. After the subsequent rolling and annealing processes, the sheet with pre-rolling deformation of two passes shows finer microstructure, which mainly benefits from the pinning effects of uniform nano-sized precipitates. As a result, the annealed sheet with two-pass pre-rolling deformation exhibits an advantageous combination of high strength and high ductility with fine microstructure, showing an ultimate tensile strength of ~297 MPa, a yield strength of ~ 205 MPa and an elongation of 25.0%. This work provides an effective method of dissolving the coarse segregative phases in the TRC Mg alloys with significant potential for industrial production. [ABSTRACT FROM AUTHOR]

A novel terpyridine derivative conjugated by tetraethylene glycol chains with a coordinative europium (III) center was prepared and the assembled complex with high water solubility exhibited sensitive pH dependence. Modulation of the luminescence could be realized at variable physiological pH values (from 8 to 2) by consecutive changes in the form and intensity of both europium and ligand emissions. The achieved multiple optical signal shifts (blue-red-green) and especially the performance of the well-defined lanthanide complex under strong acidic condition had never been reported. In vitro studies revealed that the europium complex was non-toxic to HeLa and THP-1 cells. Fluorescent microscope images supported the distribution of the emissive species and the measurement of pH fluctuations in pathogenic cells could be achieved. [ABSTRACT FROM AUTHOR]

Deformation monitoring of landslides is of great significance to characterize and understand their evolutions. Recently the distributed fiber optic strain sensing (DFOSS) technique has emerged as a powerful tool for landslide monitoring by enabling distributed and real-time measurement along a sensing optical fiber (SOF) over dozens of kilometers with high strain accuracy. However, the correlation between landslide displacements and axial strains exerted on an SOF remains elusive. Here we present a preliminary attempt to calculate shear displacements of landslides based on distributed strain measurements via a kinematic method. Parametric studies on the sliding direction, width of shear zone and magnitude of shear displacement indicate that, under certain circumstances, the shear displacements of a landslide can be well estimated without going much deep into the pattern of shear zone or the slope mass–SOF coupling condition. The proposed calculation method is validated through field shear tests of geologic granular materials, and has immediate application to the analysis of the Majiagou landslide, Three Gorges Reservoir region, China. The distributed strain measurements captured by a borehole-embedded SOF allow two sliding surfaces of this landslide to be located; one occurred at the contact between surface deposits and bedrock, whereas the other was the main sliding surface occurring within bedrock. The shear displacements along the main sliding surface are calculated using the proposed method. It is revealed that the landslide responds more aggressively to the fluctuation of reservoir water level than to the rainfall over a 1-year period. [ABSTRACT FROM AUTHOR]

This study proposes to use fractional derivatives to evaluate the long term performance of circular mat foundations overlying clays and also predict the associated ground settlement. Closed form solutions for the deflection and bending moment of foundations and the subsequent reaction of subgrade are obtained with the Mittag–Leffler function. Numerical examples are used to determine how the fractional order affects the time dependent properties of the foundation and ground settlement, and to simulate the case history of a large standpipe constructed over Tertiary sediments. New insights into design and prediction of shallow foundations and ground settlement are also discussed. [ABSTRACT FROM AUTHOR]

Two copper nanoclusters (NCs) stabilized by l -cysteine and glutathione have been reported. The nanoparticles with ultrafine size had excellent water solubility and exhibited green or red emission respectively. Particularly, the two copper clusters were found to be responsive to the presence of tetracycline (TC) and on-off quenching effects were achieved. After incubation, the cell staining and target-detection features could be still effective in two adherent live cells. The nanocluster showed very low cytotoxicity and excellent biological compatibility. Accordingly, the special photophysical properties of copper NCs will be attractive for various potential applications such as bio-sensing and medical diagnosis. [ABSTRACT FROM AUTHOR]

Nansha clay is an interactive marine and terrestrial deposited soft clay that is widely spread in Guangzhou, Pearl River Delta, China. To avoid excessive settlement after construction, there is a need for better quantifying the time-dependent deformation of the soft clay. This paper presents a preliminary study to predict the one-dimensional compression of Nansha clay using fractional derivatives. A fractional Merchant model was introduced to describe the time-dependent settlement, and analytical solutions were obtained in terms of the Mittag-Leffler function. The oedometer test results were presented to validate this model. Compared with classical rheological models, the fractional derivative-based model enabled close estimation of the one-dimensional compression with fewer parameters. The meaning of the order of fractional derivative and its relationship with the clay physical properties were explored. It shows that a smaller value of this order corresponded to a higher coefficient of consolidation and a lower coefficient of secondary consolidation. The amplitude of both the primary and secondary consolidation of clay may be estimated quantitatively by the order of fractional derivative. Taken together, these results may open up new avenues for theoretical and empirical modeling of rheological phenomena in clay using fractional derivatives. [ABSTRACT FROM PUBLISHER]

Since lanthanide luminescent materials generally possess striking and special spectroscopic or photophysical features such as sharp emission bands and long lifetimes, they have emerged as new platforms in sensory and diagnostic fields. This review aims to summarize the recent development relevant to the assembly of ligand design and fluorogenic species for a wide range of analytes. Moreover, the flexible and rigid optical frameworks include not only the molecular-based functional complexes, numerous lanthanide hybrid nanocomposite materials that lie between the interface of organic and inorganic hosts also provide possibilities to fabricate tailor-made optical probes due to their unique chemical and physical properties. The remarkable examples of newly-designed lanthanide hybrid sensing materials (siloxane or titania based hybrids, carbon-related nanomaterials, polymeric composites and noble metal based probes) are discussed in this review. [ABSTRACT FROM AUTHOR]

A novel bis-bidentate nitronyl nitroxide radical based on triazolopyrimidine, NIT-2-TrzPm (NIT-2-TrzPm = (2-(2′-triazolopyrimidine)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide)) and six new transition metal complexes of this ligand, namely [M(hfac)2(NIT-2-TrzPm)]·CH2Cl2 (M = Mn (1Mn) and Co (2Co)), [M(hfac)2]2(NIT-2-TrzPm) (M = Mn (3Mn) and Co (4Co)), [Mn(NIT-2-TrzPm)2(MeOH)2](ClO4)2·MeOH (5Mn), and [Co(NIT-2-TrzPm)2(MeOH)2]2(ClO4)4·4MeOH (6Co) were prepared and characterized structurally and magnetically. These complexes can be selectively synthesized by controlling the reaction ratio of M(hfac)2·2H2O to the radical ligand (for 1Mn to 4Co) or using metal perchlorates as the starting materials (for 5Mn and 6Co). Single crystal X-ray crystallographic analyses confirmed that 1Mn and 2Co are isostructural 3d–2p MII–radical complexes, in which the NIT-2-TrzPm radical acts as a terminal bidentate ligand chelating to one 3d ion, while 3Mn and 4Co are isostructural 3d–2p–3d MII–radical–MII complexes with the NIT-2-TrzPm radical acting as a bridging ligand between two 3d ions. For complexes 5Mn and 6Co, two NIT-2-TrzPm ligands from the equatorial positions coordinate with the metal center to form the 2p–3d–2p structures with the axial positions occupied by two methanol molecules. Magnetic analysis on the MnII complexes revealed the existence of a strong antiferromagnetic interaction between the MnII and the NIT radical spin, while weak ferromagnetic coupling for Mn⋯Mn and Rad⋯Rad in the Mn–NIT–Mn and Rad–Mn–Rad spins was confirmed. Interestingly, although the NIT-bridged complexes 3Mn and 4Co possess significantly different magnetic anisotropy, field-induced slow magnetic relaxation can be observed in both complexes, which was assigned to the phonon bottleneck effect for 3Mn and field-induced SMM behavior for 4Co. To the best of our knowledge, 3Mn is the first example of the NIT-bridged binuclear MnII complex undergoing slow magnetic relaxation. [ABSTRACT FROM AUTHOR]

The development of the powder metallurgy (PM) superalloy applied in turbine discs of high thrust-weight ratio aeroengines was reviewed. Based on the Cosserat continuum theory, the elastoplastic damage model for the PM superalloy was developed in which the microscopic properties were modeled with the characteristic lengths of the material. Furthermore, the mesh dependency of the localized bands in the analysis of softening problems was eliminated in the present model. For the softening problems, massive iterations were usually needed with the classical elastoplastic methods and may not converge in some cases. Based on the parametric variational principle, the original nonlinear problem was transferred to a complementary problem, then the efficiency and convergence of the solution were greatly improved. Finally, several numerical examples demonstrate the validity of the proposed method. [ABSTRACT FROM AUTHOR]

Real-time monitoring of landslide shear displacements is important for early warning of landslide hazards. However, distributed and real-time monitoring of landslide displacements cannot be fully realized by using existing monitoring methods. In this work, a new strain-sensing optical cable based on ultra-weak Fiber Bragg Grating (UWFBG) technology was designed. Two computational models to convert measured cable strains to shear displacements were proposed. Furthermore, experiments were conducted to verify the models. The advantage of the UWFBG cable is its ease of installation. In particular, it can be installed in abandoned inclinometer casings to extend the lifespan of existing inclinometer boreholes. The UWFBG cable and the proposed deployment method were applied to the Majiagou landslide in the Three Gorges Reservoir (TGR) area in China. Distributed deformation data were collected and transmitted to a remote computer terminal in real time (6-min interval). The monitoring results show that two shear deformation zones of the landslide were successfully identified by the UWFBG cable. The proposed method based on the UWFBG technology provides a new means to achieve distributed, real-time monitoring of landslide shear displacements. [ABSTRACT FROM AUTHOR]

Fiber reinforcement is an effective method for improving engineering properties of soil. However, the interaction mechanism of the fiber and the surrounding soil is not well understood. Based on mechanical analysis of fiber-soil interface under pullout condition, a tri-linear model is proposed to describe the shear stress-displacement relationship. The progressive pullout process of a short fiber in soil is divided into five consecutive phases: (1) the initial pure elastic phase (Phase I); (2) the elastic-softening phase (Phase II); (3) the pure softening phase (Phase III); (4) the softening-residual phase (Phase IV); and (5) the final pure residual phase (Phase V). For each phase, the analytical solutions of the distributions of tensile force, interfacial shear stress and displacement are derived. Through a comparison between the pullout test results of polypropylene fiber (PP-fiber) and the predicted results, the effectiveness of the proposed model in capturing the progressive load-deformation behavior of a short fiber in soil is verified. Moreover, the effects of water content and dry density of soil on the model parameters are analyzed in detail. It is found that the interfacial peak/residual shear resistance and shear stiffness of fiber reinforced soil significantly depend on soil compaction conditions. In general, two transition phases (Phase II and Phase IV) are not evident during the whole pullout process of PP-fiber. [ABSTRACT FROM AUTHOR]

Significance: The effect of redox signaling on hematopoietic stem cell (HSC) function is not clearly understood. Recent Advances: A growing body of evidence suggests that adult HSCs reside in the hypoxic bone marrow microenvironment or niche during homeostasis. It was recently shown that primitive HSCs in the bone marrow prefer to utilize anaerobic glycolysis to meet their energy demands and have lower rates of oxygen consumption and lower ATP levels. Hypoxia-inducible factor-α (Hif-1α) is a master regulator of cellular metabolism. With hundreds of downstream target genes and crosstalk with other signaling pathways, it regulates various aspects of metabolism from the oxidative stress response to glycolysis and mitochondrial respiration. Hif-1α is highly expressed in HSCs, where it regulates their function and metabolic phenotype. However, the regulation of Hif-1α in HSCs is not entirely understood. The homeobox transcription factor myeloid ecotropic viral integration site 1 (Meis1) is expressed in the most primitive HSCs populations, and it is required for primitive hematopoiesis. Recent reports suggest that Meis1 is required for normal adult HSC function by regulating the metabolism and redox state of HSCs transcriptionally through Hif-1α and Hif-2α. Critical Issues: Given the profound effect of redox status on HSC function, it is critical to fully characterize the intrinsic, and microenvironment-related mechanisms of metabolic and redox regulation in HSCs. Future Directions: Future studies will be needed to elucidate the link between HSC metabolism and HSC fates, including quiescence, self-renewal, differentiation, apoptosis, and migration. Antioxid. Redox Signal. 20, 1891-1901. [ABSTRACT FROM AUTHOR]

Carbon/carbon (C/C) composites have strict requirements for their thermal properties in extreme environments, especially at high temperature, where their properties are crucial for long-term life. The structure of C/C composites is exceptionally complex and exhibits multi-scale characteristics, and their thermophysical properties are closely related to temperature. Therefore, exploring their thermal response and heat transfer mechanisms through experimental method is relatively costly. This paper constructs a multi-scale finite element model to investigate the influence of structure and manufacturing defects on performance, and analyzes the thermophysical properties of the composites at High-temperature. By constructing a micro-representative volume element (Micro-RVE) that includes fibers, matrix, and pores, and using a steady-state heat transfer analysis method, the influence of material phase distribution on performance is studied. At the same time, a Meso-RVE reflecting the layering form, needle punching effect and manufacturing defects is established, and the transient heat transfer analysis method is used to investigate the influence of the structural form on performance. Finite element analysis shows that, the simulation values of the three C/C composites of unidirectional fiber bundles, short-chopped fiber felts, and needle punched C/C composites show good consistency with the experimental results in the published literature. This paper uses numerical methods to calculate the thermophysical properties of C/C composites from room temperature to 900°C and explores their variation with temperature. The constructed multi-scale model provides an accurate and effective method for predicting the thermophysical properties of C/C composites and also provides new perspectives and insights for thermal-mechanical coupling analysis and structural design. [ABSTRACT FROM AUTHOR]

• An exploratory study to examine the effect of strain on DAS amplitude response. • Exponential decrease in DAS amplitude with increasing tensile strain. • Weakened strain effect with elevated vibrational amplitude. • Implication for accurate interpretation of telecom dark fiber DAS measurements. • Toward optimal design and deployment of dedicated DAS cables in engineering systems. Absolute wavefield amplitude information is essential to amplitude-based distributed acoustic sensing (DAS) studies such as attenuation analysis, source inversion, and subsurface imaging. Here, we report the results of a pilot experimental study aimed at exploring whether and how the strain present in a fiber-optic cable would affect the amplitude response of a DAS system. Using a precise strain-controlled setup, we find that DAS amplitudes drop sharply as the fiber shifts from a loose to a strained state. This is followed by an exponential decrease in amplitude as a function of tensile strain up to 16,000 με. Additionally, the observed strain effect weakens with increasing vibration intensity. Overall, the revealed fiber strain dependence of DAS amplitude measurements may have implications for the accurate interpretation of DAS recordings acquired by preexisting telecommunications cables. It is also relevant to the design and optimal deployment of fit-for-purpose DAS cables in oil and gas wells, tunnels, and other engineering systems. [ABSTRACT FROM AUTHOR]

Background: The objective of this study was to investigate the association between pre-operative body mass index (BMI) and surgical infection in perihilar cholangiocarcinoma (pCCA) patients treated with curative resection. Methods: Consecutive pCCA patients were enrolled from four tertiary hospitals between 2008 and 2022. According to pre-operative BMI, the patients were divided into three groups: low BMI (≤18.4 kg/m2), normal BMI (18.5–24.9 kg/m2), and high BMI (≥25.0 kg/m2). The incidence of surgical infection among the three groups was compared. Multivariable logistic regression models were used to determine the independent risk factors associated with surgical infection. Results: A total of 371 patients were enrolled, including 283 patients (76.3%) in the normal BMI group, 30 patients (8.1%) in the low BMI group, and 58 patients (15.6%) in the high BMI group. The incidence of surgical infection was significantly higher in the patients in the low BMI and high BMI groups than in the normal BMI group. The multivariable logistic regression model showed that low BMI and high BMI were independently associated with the occurrence of surgical infection. Conclusions: The pCCA patients with a normal BMI treated with curative resection could have a lower risk of surgical infection than pCCA patients with an abnormal BMI. [ABSTRACT FROM AUTHOR]

The strain transfer between fiber-optic cable and soil plays a critical role in the deformation characteristics of a cable–soil interface. Existing findings cannot provide a clear understanding of the effects of key influencing factors including horizontal confining pressures, anchorage property of cables, and saturation of soils on the strain transfer and shear characteristics at the interface. A group of pullout tests of cables in soil were conducted to examine the strain transfer efficiency using the optical frequency domain reflectometry (OFDR) technique. Two kinds of cables were pulled out from sandy soil and sand–gravel–clay mixtures under the confining pressures of 0–1.2 MPa. Typical strain-hardening behavior was observed for cables with confining pressure and anchorage, and the interface shear strength could not be evaluated within the strain measurement range. To address this problem, the so-called interface shear coefficient was adopted, and the key influential factors were discussed quantitatively. The interface shear coefficient keeps a linear relationship with the confining pressure, and that of the anchored cable in saturated backfill mixtures is 2–3 times than that of the unanchored cable. These findings will guide the methods of gaining reliable data for revealing the failure mechanism of geostructures via distributed strain sensing. [ABSTRACT FROM AUTHOR]

Abstract: We report a case of a 6-month-old boy with a mixed phenotype acute leukemia (MPAL), bilineal and biphenotypic immunophenotype (B-lymphoid lineage and combined B-lymphoid and monocytic lineage) with t(10;11)(p12;q23);MLL-MLLT10. He was treated with acute myeloid leukemia protocol and in complete remission at 7-month follow-up. To the best of our knowledge, this is the first reported MLL-MLLT10 rearranged case presenting as MPAL in an infant. From a clinical practice standpoint, this case illustrates the importance of detection of MLL rearrangement due to its prognostic implication and the effectiveness of flow cytometry immunophenotyping in diagnosing MPAL and monitoring minimal residual disease. [Copyright &y& Elsevier]

Iatrogenic biliary injury (IBI) following laparoscopic cholecystectomy (LC) is the most serious iatrogenic complications. Little is known whether LC-IBI would lead to surgeon's severe mental distress (SMD). A cross-sectional survey in the form of electronic questionnaire was conducted among Chinese general surgeons who have caused LC-IBI. The six collected clinical features relating to mental distress included: 1) feeling burnout, anxiety, or depression, 2) avoiding performing LC, 3) having physical reactions when recalling the incidence, 4) having the urge to quit surgery, 5) taking psychiatric medications, and 6) seeking professional psychological counseling. Univariable and multivariable analyses were performed to identify risk factors of SMD, which was defined as meeting ≥3 of the above-mentioned clinical features. Among 1466 surveyed surgeons, 1236 (84.3%) experienced mental distress following LC-IBI, and nearly half (49.7%, 614/1236) had SMD. Multivariable analyses demonstrated that surgeons from non-university affiliated hospitals (OR:1.873), patients who required multiple repair operations (OR:4.075), patients who required hepaticojejunostomy/partial hepatectomy (OR:1.859), existing lawsuit litigation (OR:10.491), existing violent doctor–patient conflicts (OR:4.995), needing surgeons' personal compensation (OR:2.531), and additional administrative punishment by hospitals (OR:2.324) were independent risk factors of surgeon's SMD. Four out of five surgeons experienced mental distress following LC-IBI, and nearly half had SMD. Several independent risk factors of SMD were identified, which could help to make strategies to improve surgeons' mental well-being. [ABSTRACT FROM AUTHOR]

Vertical deformation can be revealed by various techniques such as precise leveling, satellite imagery, and extensometry. Despite considerable effort, recording detailed subsurface deformation using traditional extensometers remains challenging when attempting to detect localized deformation. Here we introduce distributed fiber optic sensing based on Brillouin scattering as a geophysical exploration method for imaging distributed profiles of vertical deformation. By examining fiber optic cable‐soil interaction we found a threshold in confining pressure to achieve a strong cable‐soil coupling, thus validating data collected from a borehole‐embedded fiber optic cable deployed in Shengze, southern Yangtze Delta, China. Clear‐cut strain profiles acquired from November 2014 to December 2016 allowed us to pinpoint where compaction or rebound was actively occurring and examine strain responses at various locations along the entire cable length. We suggest that distributed fiber optic sensing can complement with extensometry and remote sensing techniques for improved monitoring of vertical deformation. Plain Language Summary: Recording detailed subsurface deformation using traditional methods (e.g., extensometers) is sometimes difficult due to limited measuring points. This dilemma may be overcome by using the emerging distributed fiber optic sensing technology, which transforms common telecommunication fiber optic cables into sensors capable of making distributed strain measurements. We report the use of this technology for monitoring distributions of vertical deformation resulting from groundwater abstraction in Shengze, southern Yangtze Delta, China. An evaluation of the performance of a borehole‐embedded fiber optic cable helps us to validate the in situ strain data. The advantage of using this technology for vertical deformation sensing is the ability to locate any strata undergoing compaction or rebound and look at strain responses at any depth of interest. Moreover, recording subsurface changes in this fashion may also be useful in other geophysical and engineering applications that require refined monitoring of the media. Key Points: Distributed fiber optic sensing with Brillouin scattering provides a clear subsurface strain profile using a single fiber optic cableWe find a threshold in confining pressure to achieve a strong fiber optic cable‐soil couplingDistributed fiber optic sensing can complement with existing techniques for improved monitoring of vertical deformation [ABSTRACT FROM AUTHOR]

Two successive magnetocaloric effects consisting of inverse magnetocaloric effect around martensitic transition and negative magnetocaloric effect around magnetic transition of austenitic phase have been observed in Ni50Mn34In15Al alloy. Large inverse magnetic entropy change ΔSm ( ~ 21.3 J kg−1 K−1), small thermal and magnetic hysteresis of martensitic transition give rise of large net refrigerant capacity ( ~ 152.3 J kg−1) under a magnetic field of 50 kOe, which is comparable with that ( ~ 157.9 J kg−1) of second-order transition. The large combined magnetocaloric effects make the Ni50Mn34In15Al alloy as a promising candidate material for room temperature magnetic refrigeration. [ABSTRACT FROM AUTHOR]

A high extrusion ratio of 166:1 was applied to commercial AZ61 alloy in one step with an extrusion speed of 2.1 m·min−1. The effects of DA (direct aging) treatment on the microstructure and tensile properties of extruded alloy were investigated. The extruded alloy exhibits fine DRXed grains and the average grain size is ~11 μm. After DA treatment at 170 °C, the tensile strength and 0.2% offset yield strength is enhanced from 314 to 336 MPa and from 169 to 191 MPa respectively, sacrificing elongation from 26.5% to 23.3%. The grain size and texture distribution of extruded AZ61 scarcely evolve during the post aging treatment. However, the enhanced strength in peak-aged alloy is mainly caused by the high-density elliptical Mg17Al12 precipitates distributing uniformly along the grain boundaries or within the grains, by precipitation and dispersion hardening. Furthermore, the nano-sized precipitates effectively inhibit grains from coarsening by triggering pinning effects along the grain boundaries at elevated temperature. As a result, the peak-aged alloy exhibits a better superplasticity of 306.5% compared with that of 231.8% of extruded sample. This work provides a practical one-step method for mass-producing Mg alloy sheets with excellent tensile strength and ductility compared with those fabricated by conventional extrusion methods. [ABSTRACT FROM AUTHOR]

The multiaxial thermomechanical fatigue properties for nickel-based superalloy GH4169 in aeroengine turbine discs are investigated in this paper. Four types of axial–torsional thermomechanical fatigue experiments were performed to identify the cyclic deformation behavior and the damage mechanism. The experimental results showed that the creep damage can be generated under thermally in-phase loading while it can be ignored under thermally out-of-phase loading, and the responded stress increasing phenomenon, that is, non-proportional hardening, can be shown under the mechanically out-of-phase strain loading. Based on the analysis of cyclic deformation behavior and damage mechanism, a life prediction method was proposed for multiaxial thermomechanical fatigue, in which the pure fatigue damage, the creep damage, and the interaction between them were simultaneously considered. The pure fatigue damage can be calculated by the isothermal fatigue parameters corresponding to the temperature without creep; the creep damage can be calculated by the principle of subdivision, and the creep–fatigue interaction can be determined by creep damage, fatigue damage, and an interaction coefficient which is used to reflect the creep–fatigue interaction strength. The predicted results showed that the proposed method is reasonable. [ABSTRACT FROM AUTHOR]

Abstract A dovetail fixture for fretting fatigue test was designed. Fretting fatigue experiments were performed for Ni-based single crystal (NBSX) superalloys at 600 and 700 °C in two secondary orientations, [110] and [010]. The influence of secondary orientation and temperature on fretting fatigue behavior was investigated. The crystal plasticity finite element (CPFE) simulation was used to study the stress field at the contact region. The result indicates that the stress distribution is correlated to fretting damage, which is consistent with the crack initiation site. Fretting fatigue life is predicted based on critical plane method, which is in good agreement with the experimental result. Highlights • A dovetail fixture for fretting fatigue life test at elevated temperature was designed. • The effect of secondary orientation and temperature on fretting fatigue was studied. • The simulation agreed with experimental observation in fretting fatigue behavior. • Life prediction by critical plane method was consistent with experimental result. [ABSTRACT FROM AUTHOR]

Carbonaceous materials have long been developed to utilize “nano-spaces” and numerous guest species could be encapsulated. A remarkable fluorescence difference has been observed after newly designed pyropheophorbide-a-appended carbon nanohorns were incorporated in a cellular medium and confocal microscopy was employed for the determination of the intracellular localization. Our study supported the role of carbon nanohorns as carriers of photodynamic therapy (PDT) agents and their heating behavior was discussed. We have developed a theranostic platform based on photosensitizer-conjugated carbon nanostructures and this system has been applied in an animal model. In addition, a negligible toxicity of CNH-Pyro was found in body weight experiments and histopathological examination of the major organs. [ABSTRACT FROM AUTHOR]

The axial-torsional thermo-mechanical fatigue behavior for Ni-based superalloy GH4169 was investigated experimentally in the temperature interval from 360 °C to 650 °C. The experimental results showed that, in the same von Mises equivalent mechanical strain amplitude condition, the fatigue life can be seriously decreased when the axial mechanical strain and the temperature are in-phase, and the non-proportional loading of mechanical strains can result in the fatigue life to further decrease. The analysis results showed that the fatigue lives depend on the summation of fatigue, creep and oxidation damages. The interaction between dislocations and precipitations can induce the additional hardening under mechanical non-proportional loading, which can obviously increase the fatigue damage. The tensile mean stress and the non-proportional additional hardening can further increase the oxidation damage existed in all loading conditions, which result in the increase of inelastic strain at high temperature. Creep damage behavior on grain boundaries can be shown in the case of the high tensile stress and the high temperature acting simultaneously, and increased with shear stress at the same time. In addition, the tensile stress has an obvious effect on the nucleation of creep cavities contrasted to the shear stress at high temperature, and more creep damage can be caused by the non-proportional additional hardening. [ABSTRACT FROM AUTHOR]

Single-phase LaCr 0.7 Cu 0.3 O 3 ceramics was fabricated successfully using high pressure sintering method. A mixed valent state with the coexistence of Cr 2+ ，Cr 3+ and Cr 4+ was confirmed by X-ray photoelectron spectroscopy measurement. Magnetic measurement results indicate that in addition to antiferromagnetic superexchange interaction of Cr 3+ -O 2- -Cr 3+ accompanied by weak ferromagnetism at high temperature, two types of short-range order ferromagnetism can be observed at low temperature, which could be attributed to double exchange interactions of Cr 2+ -O 2- -Cr 3+ and Cr 3+ -O 2- -Cr 4+ , respectively. The results here would enrich the understanding on magnetic interactions in rare-earth chromites. [ABSTRACT FROM AUTHOR]

Recently the distributed fibre optic strain sensing (DFOSS) technique has been applied to monitor deformations of various earth structures. However, the reliability of soil deformation measurements remains unclear. Here we present an integrated DFOSS- and photogrammetry-based test study on the deformation behaviour of a soil foundation model to highlight the role of strain sensing fibre-soil interface in DFOSS-based geotechnical monitoring. Then we investigate how the fibre-soil interfacial behaviour is influenced by environmental changes, and how the strain distribution along the fibre evolves during progressive interface failure. We observe that the fibre-soil interfacial bond is tightened and the measurement range of the fibre is extended under high densities or low water contents of soil. The plastic zone gradually occupies the whole fibre length when the soil deformation accumulates. Consequently, we derive a theoretical model to simulate the fibre-soil interfacial behaviour throughout the progressive failure process, which accords well with the experimental results. On this basis, we further propose that the reliability of measured strain can be determined by estimating the stress state of the fibre-soil interface. These findings may have important implications for interpreting and evaluating fibre optic strain measurements, and implementing reliable DFOSS-based geotechnical instrumentation. [ABSTRACT FROM AUTHOR]

• Equivalence between the SHL MSRC and the Cane MSRC is investigated. • Equivalent conversion formulae are proposed based on skeletal point stresses. • The equivalent conversion formula is found to be principal stress sign-dependent. • Equivalent conversion formula appropriate to the creep crack is suggested. Multiaxial creep life prediction of components has been challenging. To cope with the challenge, efforts have been made to develop suitable multiaxial stress rupture criteria (MSRC) based on representative stress concept. Of all MSRCs, the ones due to Sdobyrev and Hayhurst-Leckie (denoted as SHL MSRC), and to Cane (denoted as Cane MSRC) are commonly-used. In this work, the equivalent conversion between the SHL MSRC and the Cane MSRC is investigated based on skeletal point stresses. Equivalent conversion formulae are proposed based on the skeletal point stresses of circumferentially-notched tension (CNT) specimen, and then validated by comparison with the experimental data available in the literature. The equivalent conversion formula between the two MSRCs is found to be dependent on the signs of principal stresses. Therefore, different conversion formulae should be chosen depending on the signs of principal stresses. Afterwards, the applicability of different equivalent conversion formulae is demonstrated for the CNT specimen when skeletal point stresses are available, and for creep crack growth specimen when skeletal point stresses are not available. Finally, the equivalence of the two MSRCs is discussed. [ABSTRACT FROM AUTHOR]

In order to understand the activity characteristics of low-level jets in the Nanjing area, statistical analysis and comparative study are carried out on their monthly and diurnal variations, characteristics of their cores and accompanying weather conditions using wind profile data in 2005—2008 collected by two wind profilers. The results show that low-level jets have significant monthly and diurnal variations. They occur more frequently in spring and summer than in autumn and winter and are more active in early morning and at night, with the maximum wind speed usually occurring at midnight. The central part of the low-level jet occurs mainly at the height of less than 1400 meters, and the enhancement of central speed is beneficial to the appearance of precipitation. Meanwhile, when the low-level jet appears in summer, it helps cause heavy rain. The statistical results of the boundary wind profiler are well consistent with those of the tropospheric wind profiler. Two kinds of wind profilers also have the capability of continuously detecting the development of low-level jets. [ABSTRACT FROM AUTHOR]

In this research, a novel terbium-based luminescent hybrid inorganic/organic probe was designed and synthesized. Mesoporous silica nanospheres dispersed in water were used as the appropriate host for the covalently linked lanthanide-containing organic structures. The lanthanide structure was linked to a sulfonate ester unit, which, in the presence of biothiols, was cleaved to result in terbium emission. The hybrid probe exhibited the capabilities of quantitative determination and detection limits for biothiols were presented (36.8 nM for Cys, 32.5 nM for GSH, and 34.7 nM for Hcy). Evaluation of luminescence changes in cell culture demonstrated that this smart probe is cell membrane permeable and selectively lights up in the presence of cysteine and glutathione in human embryonic kidney cells and human lung adenocarcinoma cells. This variation in the presence of biothiols can be controlled by the treatment with N-methylmaleimide. The narrow line-like bands and long-lived excited states of this terbium luminescent sensor allows the discrimination of scattering signals and interfering fluorescence derived from biological tissues. [ABSTRACT FROM AUTHOR]

The distributed optical fiber sensing systems have played an increasingly important role in monitoring civil infrastructures over the past few years. One of the main challenges of their applications to geotechnical monitoring is to increase the reliability of strain sensing optical fibers in measuring the deformation of surrounding soil masses. In this paper, a pullout test method is proposed to characterize the deformation compatibility between an optical fiber and soil. A series of pullout tests on three types of sand-embedded optical fibers are conducted to investigate the performance of the fiber–sand interface. Based on the test results, an explicit tri-linear pullout force–displacement relationship is proposed to describe the mechanical behavior of the fiber–sand interface. The performance of the three fibers regarding fiber–sand interaction mechanism is evaluated in terms of ratio of effective pullout displacement to diameter, ratio of residual pullout displacement to diameter, peak shear strength and residual shear strength. All four parameters of the three fibers are found to have approximately linear relationships with the applied confining pressure, which reveals that the deformation compatibility of the fiber–sand interface is utterly dependent on the confining pressure. For all the three fibers, the first shear stiffness coefficient is about 8 N/mm and the ratio of residual to peak shear strength is about 0.5. Furthermore, the Mohr–Coulomb failure criterion is used to get the cohesions and friction angles of the three fiber–sand interfaces. Through a comparison of the pullout performance, one out of three types of fibers tested is found to be more preferable for soil deformation measurement in laboratory-scale tests. The conclusions can provide valuable references for predicting the fiber–soil interface behavior and evaluating the reliability of strain monitoring data. [ABSTRACT FROM AUTHOR]

The structural components prone to erosion damage often exhibit irregular and complex shapes. Predicting erosion rates for such irregular geometries is a field that needs more attention, since it can be used to evaluate the performance of the component. This study aims to develop an evaluation method for predicting erosion rates of components with complex geometry. Standard erosion tests were performed on small plates to investigate the effects of different impact angles and particle velocities on the erosion rate of the target material. Based on these test results, the Newton iteration method was employed to determine the parameters of the Tabakoff and Grant erosion model. Moreover, these parameters were used in computational fluid dynamics simulation of components with complex geometries. Besides, a model was developed to convert the erosion rate density into erosion rate in numerical simulation, allowing quantitative comparison of simulation results with experimental data. The calibration of the erosion model parameters was conducted by using 1060 aluminum alloy specimens. The predicted erosion rate changes with impact angle showed consistency good agreement with the testing data. Subsequently, the erosion rate of a simplified similar structure for aircraft engine blade made of 1060 aluminum alloy was predicted and verified. • Determined optimal Tabakoff and Grant erosion model parameters for 1060Al by standard erosion tests. • Quantitative evaluation of erosion rates for components with complex geometry. • A model for conversion of erosion rate density to erosion rate was proposed. • Effectively predicted erosion rates for a simplified structure of aircraft engine blade. [ABSTRACT FROM AUTHOR]

Ultrasonic surface rolling process (USRP) is a combination of ultrasonic impact and deep rolling techniques. However, the addition of ultrasonic vibrations complicates the working mechanism of USRP tools. Existing studies rarely consider the evolution of dynamic characteristics in USRP tools resulting from changes in ultrasonic amplitudes, which undoubtedly exert a significant influence on surface properties. Moreover, they typically limit the ultrasonic amplitude to a small range. This study aims to identify the boundary process parameters to differentiate between stable and unstable dynamic characteristics during USRP and to compare their effects on the surface integrity and the plastic deformation. Therefore, an equivalent USRP tool model was proposed to analyse the working mechanism at a large-scale ultrasonic amplitude. The boundary USRP parameters responsible for different dynamic characteristics were experimentally explored. Finally, comparative USRP experiments on the Ti-6Al-4 V alloy were conducted, and it was observed that USRP parameters under stable dynamic characteristics were beneficial to the excellent surface roughness. Conversely, altering the ultrasonic amplitude to attain unstable dynamic characteristics leads to a notable degradation in the surface quality; however, the extent of plastic deformation is significantly increased. This study provides insights into the effects of dynamic characteristics in USRP, thereby contributing to a deeper understanding of the process and facilitating effective design of process parameters. [Display omitted] • The working principle of ultrasonic surface rolling processing (USRP) is analyzed under large-scale ultrasonic amplitudes. • There is a critical ultrasonic amplitude or static value beyond which the dynamic characteristics of the USRP tool change. • Different dynamic characteristics of the tool result in distinct surface properties. • A boundary parameter curve has been developed to provide guidance for the design of process parameters. [ABSTRACT FROM AUTHOR]