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Monitoring and modelling surface deformation are crucial components of understanding the freeze‒thaw process and preventing disasters in permafrost regions. However, previous methods had limitations that inhibited the interpretation of freeze‒thaw deformation, such as a lack of physical meaning, an inability to reflect the physical freeze–thaw process and consideration of only a single external factor’s impact on permafrost deformation. This study proposes an improved degree-day model (IDM) for quantitatively isolating surface deformation using interferometric synthetic aperture radar (InSAR) technology over permafrost. We considered the effect of soil moisture variation on permafrost deformation and incorporated interannual variation in the freeze‒thaw process due to climate change. By applying small baseline subset (SBAS) technology to Sentinel-1 InSAR measurements over the Wudaoliang permafrost region on the Qinghai‒Tibet Plateau from 2018 to 2019, we estimated long-term and seasonal permafrost deformation. The reliability of InSAR results was validated using in situ measurements, with root mean square errors (RMSEs) less than 10 mm. The results showed that the average linear deformation rates in 2018 and 2019 were −3.8 mm a−1 and −11.0 mm a−1, respectively, and the maximum seasonal deformations were 15.7 mm and 13.2 mm, respectively. Compared with the original degree-day model (ODM), the method used in this study produced smaller residual deformations of 6.9 mm and 6.4 mm, highlighting its ability to improve a quantitative description of permafrost deformation. [ABSTRACT FROM AUTHOR]

AbstractThis study compares dip brazing and TIG welding operations carried out under optimal conditions on the parameters of strength, deformation, and ability to resist shocks for Al-64430 joints, which find extensive use in automobile and telecommunication industries. The fabricated samples were tested for bump test, surface deformation, microhardness and tensile strength, and the joint properties were studied through SEM, EDAX mapping and EDX. Compared to the dip-brazed samples, the TIG welded samples achieved 161% greater strength and 1000% greater elongation but subsequently 1330% higher surface deformation. Both joints were able to pass the bump test; however, some degree of cracks were observed post testing in both samples. Both samples achieved similar joint microhardness values, but notably, compared with the TIG welded sample, the brazed sample showed no HAZ zones in terms of microhardness variation, where a substantial decrease in microhardness was recorded. This absence of the HAZ region was also confirmed through the microstructure. Both primary and secondary silicon were observed in brazed samples, which had finer grain sizes than did the welded samples. Dendrite formation was observed for the brazed samples, whereas a uniform distribution of aluminium was observed for the welded samples. Fractographic analysis revealed brittle intergranular fracture with small dimples present at the fracture point for the brazed joints, while out-of-plane fracture with sharp edges indicated a more ductile nature for welded joints. [ABSTRACT FROM AUTHOR]

AbstractHydrodynamic-induced landslide is a type of landslide whose stability can be reduced by rainfall, groundwater or reservoir water level fluctuations (RWLF). Based on the monitoring data of Wangjiashan landslide located in the reservoir area of Baihetan Hydropower Station, this article illustrates the deformation characteristics of Wangjiashan landslide on time and space distribution. Spearman correlation coefficients are used to make analysis of the relationship between surface deformation and different dynamic factors such as RWLF, seismic activity, and rainfall. The results indicate that RWLF is a dominant dynamic factor of Wangjiashan landslide. Besides, two variables of deformation factors are presented to find differences during various deformation periods. The results show that the displacement and its rate are both strongly correlated with the RWLF, especially during the acceleration period and the deceleration stage. It is indicated that Wangjiashan landslide is a typical hydrodynamically induced landslide. This study provides a useful reference for understanding the instability mechanism of the landslide. [ABSTRACT FROM AUTHOR]

In natural rock masses, joints or fractures usually occur at different penetrations. To study the deformation and failure behavior of rock mass with different fracture penetrations, a series of triaxial compression experiments were conducted on rock specimens containing prefabricated fracture at penetrations of 0%, 25%, 50%, 75% and 100%. The results show that the greater the fracture penetration and the smaller the strength of the rock sample, the more obvious the plastic deformation section of the stress–strain curve. Confining pressure can greatly improve the compressive strength of rock samples. For intact rock samples, confining pressure will change the failure mode from tensile failure to shear failure. For fractured rock samples, the confining pressure will aggravate the degree of damage to the rock sample. PFC 3D simulation shows that the failure process of rock samples is accompanied by the transformation of strain energy to damping energy and particle sliding energy, which can quantitatively characterise the damage process of rock. The increasing trend of crack number is slow-steep-slow, which is the 'S' type. It began to grow rapidly after reaching peak strength and gradually stabilised after reaching residual strength. It is consistent with the trend of energy change. The article carried out multi-scale experimental study of fractured rock mass with the same length and different penetration. The larger the fracture penetration, the lower the strength of the rock sample, and the more complex the crack when it is destroyed. The article analysed and summarised the mechanical properties and failure modes of rock samples with different fissures under different confining pressures and clearly recognised the deterioration effect of fissure penetration on rock samples. PFC 3D was used to simulate the test, which clearly showed the crack propagation process of fractured rock samples under triaxial compression, quantitatively characterised the damage law and revealed the failure mechanism. [ABSTRACT FROM AUTHOR]

Frictional sliding creates distinct microstructural and chemical discontinuities between the subsurface layer and base materials, which dictate the friction and wear properties. Traditional methods for lowering friction and wear in metals primarily rely on strategies that lower the interfacial shear strength between the contacting discontinuities. Contrary to conventional wisdom, we propose an alternative strategy: introducing tribo-induced or pre-designed heterostructures to suppress tribo-induced strain localization, thus yielding superior tribological properties unachievable with their conventional homogeneous counterparts. Citing recent experimental examples, this review explores the multiscale heterogeneities contributing low friction and wear, by interlinking surface deformation mechanisms and applied tribological conditions. [ABSTRACT FROM AUTHOR]

The additional deformation of slab track structure subject to arbitrary soil deformation, and subsequently the dynamic deformation coordination between the track and the soil due to a moving vehicle are of significant importance in the analysis of vehicle-track-soil (VTS) interactions. In this work, the finite element modeling and numerical iterative method are presented to compile a simulation program to reveal the deformation coordinated process of slab track-soil interaction reasonably, where the contact-separation relationship at the slab track-soil interface, the interlayered gap between slab track and soil surface, and additional track deformation are derived as additional geometric excitations of VTS interaction system. In numerical studies, different slab track types considering the unit and the longitudinal connected base plates are taken as illustrative and comparative examples, where the deformation coordinated mechanism of slab track-soil interaction and its influence on vehicle-induced vibrations are clarified. [ABSTRACT FROM AUTHOR]

This article employs Mindlin's first-order shear deformation theory to analyze the dynamic behavior of laminated composite shells with various geometries, featuring central cutouts and cracked corners that carry concentrated and distributed mass. The formulation considers an isoparametric element with nine nodes and five degrees of freedom per node. Both in-plane and transverse effects of mass are addressed by incorporating lumped mass with rotational inertia in the formulation. The obtained results are compared to previously published data, showing an excellent agreement with a variation of less than ±2.5% for all cases. Following validation, the study examines shell vibration for various geometries carrying concentrated mass, distributed mass, and distributed patch mass. Additionally, the dynamic analysis of shell panels with central cutouts and cracked corners with different cracked dimensions is conducted. Unique boundary conditions are introduced by applying them to both the outer and cutout edges (i.e., SSSS-CCCC, FFFF-CCCC). [ABSTRACT FROM AUTHOR]

Abstract\nThe inherent brittleness of unidirectional fiber-reinforced composites represents a major complication in their broad practical applications. However, exploiting different reinforcement architectures can offer an opportunity for highly desirable ductile fracture nature. This article is aimed at investigating experimentally the tensile behavior of an epoxy laminate reinforced by different layers of plain weft-knitted fabrics. The fabricated laminates were subjected to uniaxial tension in different loading directions, and the corresponding tensile responses were recorded. Basic mechanical properties were characterized and digital image correlation (DIC) was employed to capture surface deformations. Tensile test results demonstrated strong nonlinearity and pseudo-ductility as well as loading-direction dependence in this type of composite laminates. Fracture tests were conducted showing high fracture toughness ranging from 10 to 20 MPa·m1/2. Typical damage modes were characterized using microscopy, which were coupled to a few distinct tensile deformation stages. This work demonstrates that weft-knitted composites are promising in permitting great amounts of pseudo-ductility with clear warning before complete failure. It is also expected to contribute to the understanding of the specific role of weft knit fabrics in composite laminates.Analysis of the deformation process of plain weft-knitted composites and various failure modes by DIC and microscopy.Observation and explanation of pseudo-ductility in the knitted composites subjected to off-axis tension.Translaminar fracture toughness measured by over-height compact tension (OCT) specimens. Flaw insensitive length scale estimated on the order of 10 mm.Yarn loop reorientation permitted by matrix plasticity contributing to identified stiffening in off-axis specimens. [ABSTRACT FROM AUTHOR]

This article analyzes the bending behavior of functionally graded sandwich plate structures submitted to sinusoidal loads using the hyperbolic quasi-3D shear deformation plate theory. In this theory, the number of unknowns is reduced from six to only five unknowns using an undefined integral without needing any shear correction factor. Furthermore, the effective constituent material properties of the upper and lower layers of the functionally graded sandwich plate are assumed to vary smoothly and continuously only in the thickness direction. In contrast, the core layer is still homogeneous and isotropic. The governing equilibrium equations of simply supported functionally graded sandwich plates are derived using the principle of virtual displacement. Their analytical solution is obtained using Navier's technique for various schemas of functionally graded sandwich plates. The effects of the power law index, side-to-thickness ratio, and aspect ratio on the bending behavior are investigated. [ABSTRACT FROM AUTHOR]

Adequate prediction of surrounding ground movement during braced excavation is critically important as excessive soil movement damages adjacent structures. The magnitudes and patterns of ground movement and wall deflection largely depend on excavation parameters like thickness of diaphragm wall, wall embedment depth, strut locations and soil parameters such as soil strength, compressibility and creep parameter. In the present paper a thorough, parametric study has been conducted using finite element (FE) analysis to address the influence of various parameters on deformation characteristics of braced excavation in soft clayey deposits. The importance of correct estimation of soil parameters for braced excavation design is also documented. The analysis of typical braced excavations in soft clay is carried out using PLAXIS 2D software where soft soil creep constitutive model is used. On the basis of numerical study a handy design guideline is recommended. Further multivariate regression models are developed incorporating various important excavation parameters for the adequate prediction of maximum wall and ground displacement along with wall and ground surface deformation profile. Here large numbers of data reported in case histories and generated artificially from FE analysis are used for formation of regression equations. The proposed model is validated comparing results from literatures not used for the development of the model. [ABSTRACT FROM AUTHOR]

To systematically and thoroughly analyze the sensitivity and reliability of the MSBAS regularization for the estimation of surface deformation over a mine in combination with an application example, this study processed 101 Sentinel-1A/B SAR images, constructed and solved the 2D deformation models using SVD and Tikhonov regularization methods with different orders and parameters, and estimated the vertical and east-west surface deformation time series in a mine of China. Then, this study collected the leveling-monitoring vertical surface deformation data on three leveling points, and compared and analyzed the sensitivity and reliability of the MSBAS regularization methods for estimating vertical surface deformation. The results indicate that different regularization orders and parameters can lead to thousands of times differences in condition numbers and significant differences in illposed degree of the deformation models. The zero-order Tikhonov regularized deformation model with regularization parameter of 0.1 has the minimum condition number and the equation is not ill-posed. The first-order Tikhonov regularized deformation model with regularization parameter of 0.001 has the maximum condition number and the equation is seriously illposed. As a result, the estimates of 2D surface deformation models with different parameters and orders are also different in terms of numerical values and accuracy. Compared with the leveling-monitoring data, the first- and second-order MSBAS regularization methods with parameter 0.1 have the minimum fluctuation and the maximum correlation coefficients between the estimated values and the leveling-monitoring values, and are also closest to the leveling-monitoring results with the highest accuracy. [ABSTRACT FROM AUTHOR]

The Kumaun Himalaya is considered as the most active part of the Central Seismic gap in the Indian Sub-continent. In this paper, we presented active surface deformation rates of the Kumaun region from February 2017 to February 2021 using the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) technique. The cumulative displacement that occurred during the span of 4 years is ±55 mm, whereas the Line of Sight (LOS) deformation velocity rate ranges is ±7 mm/yr. Apart from PSI, we also estimated the b-value of the Kumaun region from 1803 to 2021 (399 events) and its value is 0.54 ± 0.03. A distinct NE-SW trend of b-value is observed where earthquakes with M>6 occurred towards NE of this trend. The PSIderived deformation reveals that the central part of the Inner Lesser Himalaya along with the Main Central Thrust (MCT) zone is dominated by uplift. The zone between the Munsiari Thrust (MT) and MCT in the central region shows the maximum uplift ranging 5-7 mm/yr which exactly lies above the mid-crustal ramp of the Main Himalayan Thrust (MHT). Our results are well corroborated with available observations of geodetic strain and peak ground acceleration values. However, the deformation patterns and highvelocity rates in the central part of the study area between MT and MCT indicate the accumulation of high stress. [ABSTRACT FROM AUTHOR]

This study addresses effect of shotpeening on surface characteristics of AA6061-SiCP composite. Aluminium composites with reinforcements of solitary and multiple particles are widely employed in the transportation, aerospace, and automotive sectors due to their exceptional properties, such as strength, stiffness, and wear resistance. However, the surface characteristics such as hardness, wear, and frictional properties are not improved much. To attain better surface properties, surface modification has become necessary. Therefore, shotpeening is employed with selected parameters to analyse surface topography before and after shotpeening using optical and scanning electron microscopes. Then, the average crystalline size (ACS), dislocation densities, and micro-strain are calculated with the X-ray diffraction (XRD) analysis and then correlated with the hardness of shot peened AA6061-SiCP composites in comparison with the untreated surface. The results demonstrate that increasing the shotpeening exposure durations improves surface characteristics compared to untreated AA6061-SiCP composites. At 140 s of exposure time, the micro-hardness is increased to approximately 143HV, crystallite size is refined to approximately 33.7 nm, micro-strain is enhanced by about 3.1 × 10−3, and dislocation density is increased by about 19.2 × 10−14 m−2. Severity of the shotpeening develops severe plastic deformation results in surface fracture and an increase in roughness of AA6061-SiCP composites. [ABSTRACT FROM AUTHOR]

The excellent shape stability of thermally expanded metamaterials and the good bandgap properties of acoustic metamaterials have a wide range of promising applications in aerospace and sensors. Here, a bi-material-directional honeycomb metamaterial (BHM) with tunable coefficient of thermal expansion (CTE) and bandgap properties is proposed. The theoretical analysis and numerical simulations are employed to reveal the thermal deformation mechanism of the BHM. In addition, the analytical expression of the effective Young's modulus is established by considering both tensile and bending deformation. Based on the Bloch theorem, the band structures of the BHM are calculated by the finite element method. Parameter analysis confirms that the CTE and bandgap of the BHM can be simultaneously regulated and drastically adjusted by changing the geometric parameters and material combinations. Meanwhile, the coupling relationship of the effective CTE, Young's modulus, and total effective bandgap width are investigated. The results show that the BHM can have tunable CTE function and large total effective bandgap width by selecting suitable parameters while satisfying stiffness requirements. This study achieves a dual objective of specific CTE properties and bandgap design through rational material selection and shape design, which makes the metamaterials have better tunability and multifunctionality. [ABSTRACT FROM AUTHOR]

The mining-induced subsidence has caused severe casualties and poses a threat to the safe operation of coal extraction, especially under the roads, buildings and rivers. This alarming situation demands the large-area subsidence detection and the large-gradient deformation monitoring to ensure safety. Although the traditional Interferometric Synthetic Aperture Radar (InSAR) technology can monitor surface deformation in high accuracy, unfortunately, it often fails to recover the sufficient deformation when facing the effects of decorrelation and large gradient displacement. Therefore, this study firstly proposes a Stacking-InSAR and coherence gradient fusion method to detect the mining-induced subsidence over large area. Secondly, the robust offset tracking method is applied to retrieve the large-gradient deformation in Buertai mining site. Both Gaofen-3 and Sentinel-1A Synthetic Aperture Radar (SAR) datasets are acquired over the border of Shaanxi and Inner Mongolia, China, for experimental test. The results show that 179 mining-induced subsidence sites are detected with the proposed method, and the complete spatial temporal deformation fields are obtained by both Gaofen-3 and Sentinel-1A offset tracking method with maximum deformation of 3 m in range direction. This study provides a valuable tool for detecting the fine boundary of mining subsidence and recovering the accurate deformation time series. [ABSTRACT FROM AUTHOR]

This study assumes that surfaces in outdoor environments in early childhood education and care (ECEC) institutions exert an important influence on children's play diversity. Gibson (1979) claims that surfaces are important because they are where most action occurs; some surfaces may lead to a diversity of play behaviours, while others afford a narrower range of actions. This study was conducted as part of a three-year mixed-methods project. The sample consisted of 464 video observations (mean duration: 122 seconds) of 79 children's free play in the outdoor environments of eight ECEC institutions. Multilevel regression analysis, controlled for children's age and gender, indicated that functional play was positively associated with surfaces resistant to deformation (e.g. rubber) and that constructive play was positively associated with surfaces with low resistance to disintegration (e.g. sand or forest floor). These results can help develop and design outdoor environments that facilitate children's play diversity in ECEC. [ABSTRACT FROM AUTHOR]

Surface movements pose a critical issue requiring prompt detection and monitoring to ensure safety. To address this concern, the detection and continuous monitoring of surface deformations have gained importance. While numerous point-based surveying methods exist, multi-temporal interferometric synthetic aperture radar (InSAR) analysis has emerged as a powerful technique capable of detecting deformations across large areas with freely available SAR images and software. However, the significance of surface movement forecasting must be addressed, as it plays a significant role in preventing accidents and implementing precautionary measures. In light of this, a comprehensive study was conducted at the new Istanbul Airport in Türkiye, employing the Persistent Scatterer InSAR (PSI) method with a collection of 211 Sentinel-1 SAR images. The results obtained were investigated, and six test case regions were determined for the forecasting analysis in terms of time series movement type (subsidence, uplift, and stable) and structure type (runway and building) using various machine learning (ML) algorithms. To accomplish this, regression-based and sequential-based ML algorithms were employed and compared, showing the potential of cutting-edge techniques. The Stacked LSTM algorithm was the most effective in generating accurate forecasts. Furthermore, by incorporating exogenous variables into the forecasting analysis, the study improved the accuracy of the results. To gain deeper insights into the impact of these exogenous variables, feature importance analysis was conducted using the permutation feature importance method. The results obtained were examined, considering both the structure type and the characteristics of the time series data. [ABSTRACT FROM AUTHOR]

Remote sensing techniques, such as Interferometric Synthetic Aperture Radar (InSAR), have the potential to document and monitor surface deformation up to a millimetre scale especially in areas where ground monitoring is not feasible. The InSAR technique has been used to isolate and map some current and potential landslide areas in Kinnaur region of the Satluj Valley in Himachal Pradesh. The fragile ecosystem of Kinnaur has been challenged by the shifting climatic pattern and immense anthropogenic pressure associated with burgeoning hydroelectric projects, leading to destructive landslides of epic proportions. Three recent landslides that occurred at Ribba and Pangi villages of the Satluj River Valley and the Batseri landslide in the Sangla Valley were studied and potential landslide areas along the Satluj Valley were mapped with Sentinel-1 multi-baseline interferograms using data acquired between 2016 and 2021. The analysis suggests significant changes in velocities (±11 mm/y) where the subsidence rate ranges from −6 to −11 mm/y with a cumulative displacement of ±45 mm/y. Our study highlights the potential locations for future landslides and provides an early warning landslide map to support future disaster prevention in highly deformed regions. [ABSTRACT FROM AUTHOR]

Adhesive sealing tapes play an important role in ensuring the air tightness of the building, affecting the indoor microclimate and efficient energy use. However, there is still a lack of objective indicators that would demonstrate the ability of the sealing tape to ensure the long-term air tightness of the sealing joints of various building structures. Therefore, the purpose of this work is to investigate the indicators demonstrating the suitability of adhesive sealing tapes for sealing building structures of different surfaces and deformation, to provide detailed analyses of the results, and to propose practical recommendations. The investigated self-adhesive tapes differed in backing (nonwoven material, plastic reinforced film, paper, metal foil) and adhesives (acrylic and butyl). The materials of the sealed structural joints were plywood, OSB, plasterboard, cement sawdust board, plastered board, and plastic. The thickness, deformability, peel and shear adhesion of the self-adhesive tapes were used to determine its suitability for sealing of different structural joints. It was determined that tapes with higher deformability are more versatile, as they are suitable for sealing joints subjected to small and large deformations. The higher peel adhesion is typical for tapes of an air-permeable non-woven material backing and a thin adhesive layer. Tapes with a thicker adhesive layer are most suitable for sealing complex-shaped joints. Tapes with acrylic adhesive have a higher peeling force from smooth and moderately smooth surfaces, whereas butyl adhesive creates better contact with uneven surfaces in highly deformable joints. [ABSTRACT FROM AUTHOR]

The existing prediction methods have complex model application, high requirements for data parameters, and are limited to the prediction of a single observation point. To address this problem, this paper proposes a deep learning-based surface subsidence prediction method. Taking Hefei City of China as the research area, the time-series surface deformation results of this area are obtained by using SBAS-InSAR, and then the SFLA intelligent algorithm and Elman neural network model are combined to predict the surface deformation of key urban areas, and the prediction results are compared and analyzed.The experimental results show that the prediction model proposed in this paper can not only accurately predict a single deformation point, but also predict regional land subsidence, and can be used for auxiliary decision-making of urban spatial planning, early warning of geological hazards and hazard mitigation. [ABSTRACT FROM AUTHOR]

Steel tubes find widespread applications in various structural elements, including load-bearing columns, stair guardrails, and security bollards, due to their high strength and durability. However, these structures are susceptible to damage under impact loading conditions. While prior studies have focused on drop hammer shapes like rectangles, wedges, cylinders, and hemispheres, research on the impact of a conical-shaped hammer on square and rectangular steel tubes remains limited. Therefore, this study aims to analyse the damage resulting from the impact of a conical-shaped hammer on square steel tubes using nonlinear Finite Element Analysis (FEA) software ABAQUS/Explicit. The investigation explores the effects of various parameters, including tube geometry, impact location, impactor mass, and impact height, on tube deformation and fracture behaviour of tube. Through comprehensive analysis, it was observed that the impacted site exhibited punching failure accompanied by inward bending of the tube, while outward buckling occurred at the support. The energy absorption process was examined, and the effect of the aforementioned parameters on the energy absorption capacity (EAC) was assessed. The findings indicate that the thickness of the steel tube has the most significant impact on the impact force and EAC. Additionally, the deflection of the tube was primarily influenced by the length of the hollow section. [ABSTRACT FROM AUTHOR]

Deposition path patterns play an important role in controlling residual stresses and deformation in direct energy deposition-arc (DED-arc) process. In this paper, the effects of various path patterns on the evolution of the temperature history, residual stress distribution, and substrate deformations are investigated through experiments and finite element analysis. The predicted results of temperature fields and substrate deformations are verified experimentally by the infrared thermal imager and the laser profile scanner, respectively. It is found that the path patterns have significant effects on the stress distribution in the first few layers, and the minimum substrate deformation is obtained by the zigzag path along the short edge of the block. The proposed finite element method and measuring method are confirmed to be effective and feasible, providing valuable insight into the residual stresses and deformations control in the DED-arc process. [ABSTRACT FROM AUTHOR]

In this paper, two-dimensional (2D) structural models are used to analyze thin-walled stiffened structures. A novel approach is presented to model both skins and stiffeners using 2D finite elements (FEs) with enhanced capabilities. The deformation of the stiffeners is accurately described using higher order Lagrange polynomials, and the mechanical continuity between the reinforcements and the skin is automatically ensured in correspondence of the Lagrange points. The 2D FEs are built using the Carrera Unified Formulation (CUF), which allows arbitrary refinement of the stiffener kinematics. In this way, any type of deformation can be described and, if a higher-order model is used, the three-dimensional (3D) stress distribution can be evaluated. The proposed model is tested on a stiffened plate and compared with results obtained using traditional FEA, including 3D and 2D models and a combination of 2D and one-dimensional (1D) models for the stiffeners. The results show and demonstrate the reliability of the proposed method, both in terms of displacements and stresses, when compared to the 3D solution. In addition, the computational cost, evaluated here as the number of degrees of freedom (DOFs), is much lower. Finally, the ability of this model to deal with curved stiffeners is demonstrated with practical examples. [ABSTRACT FROM AUTHOR]

Self-replenishable ways of applying solid lubrication in tribological systems are limited to the use of sintered self-lubricating composites. These are obtained by mixing solid lubricants with metallic powders or by the in situ precipitation of the lubricating phase. Both techniques can produce self-lubricating composites able to promote low friction coefficients in dry sliding conditions. However, the combination of solid lubricant and matrix is limited by the thermodynamic interactions during sintering. Filling the pores of sintered parts with solid lubricants by vacuum impregnation is a versatile way to promote solid lubrication, allowing any combination of solid lubricant and matrix to be used, avoiding deleterious phases and other sintering problems typical in sintered self-lubricating composites. In this work, low alloy sintered steel was produced by mixing Astaloy CRL powders with 0.6 wt% C, the sintered specimens were impregnated with graphite (1.10 μm), and the durability and wear rates of the resulting composites were studied using ball-on-flat reciprocating tests. The results show that the impregnation technique is able to fill the surface pores with graphite, producing friction coefficients down to 0.06 in dry-sliding conditions and wear rates ranging from 10−4 to 10−7 (mm3/N-m). The main wear mechanism of the impregnated specimens was plastic deformation on the surface, which causes sealing of pores, while the wear of the counter-bodies was mainly abrasive. The durability of the lubricity regime is directly proportional to the amount of lubricant available as pores get sealed by the sliding action of the counter-body, so is proportional to the porosity. [ABSTRACT FROM AUTHOR]

In this study, surface modification and deformation behaviour of different engineering materials were microscopically examined by an approach called cold spray additive manufacturing (CSAM). The CSAM is a layer-by-layer deposition technique for repairing and coating the deteriorated or dimensionally unstable surface. Furthermore, in this study, both the experimental and numerical investigation have been carried to understand the surface modification approach. In the experimental procedure, the de Laval nozzle accelerates the microsize particle at a high velocity on the substrate to obtain the uniform surface coating. Engineering materials like copper, aluminium, titanium and mild steel were probed with different ranges of velocities. Additionally, an explicit/Abaqus finite element approach was used to investigate the bonding between particle and substrate by using the high velocity of particles. At the interface, refining meshing size reduces the beginning velocity for adiabatic shear instability (ASI). For the different combinations of particles and substrates like copper/copper, aluminium/aluminium, titanium/aluminium, aluminium/ titanium, and copper/mild steel at perpendicular impact, the adiabatic shear instability was numerically estimated. Deformation behaviour for multi-impact has also been seen with different particle diameter sizes to determine coating phenomenon. Furthermore, the characterisation technique called scanning electron microscopy (SEM) also showed the uniform coating on the substrate. [ABSTRACT FROM AUTHOR]

Coarse-grained mixtures composed of coarse gravels and fine sands are widely used in subgrade constructions, coarse gravels of which contain rubbles and pebbles with different roundness (Rd). To investigate the effect of gravel shapes on the compaction behaviours of subgrades, the real-shaped gravel particles with varying Rd (0.2–0.5) were selected to establish coarse-grained mixtures models via the discrete element method (DEM). The contact parameters in DEM models were determined through a series of calibration tests, and the reliability of models was verified by vibration compaction tests with rubble-grained and pebble-grained mixtures. The evolutions of porosity, particle motion, and contact relationship affected by Rd were revealed from the macro-and mesoscales, and the influence of Rd on the stability of skeleton structures is discussed. As Rd decreases, the contact number tends to increase and the distribution of strong contacts is more uniform, the skeleton structure in which can effectively inhibit the motion of fine particles and the sliding between coarse particles. Conversely, the increase in Rd will cause the concentration of strong contacts, which further results in the sliding damage of skeleton structures and the improvement of compaction deformation. [ABSTRACT FROM AUTHOR]

Surface residual stress is made on the aero-engine blades by shot peening to improve the fatigue life of the blades. As the service time increases, the surface residual stress is decreasing due to thermomechanical relaxation and the centrifugal load caused by high-speed rotation. Therefore, the surface residual stress detection is of great importance for predicting the remaining life of aero-engine blades. Up to now, efficient and non-contact detection of surface residual stress is still a challenge. In this paper, an active thermal deformation excitation (ATDE) method for surface residual stress is proposed. According to the thermal deformation theory, the thermal deformation of the material is positively correlated with the surface residual stress, and by measuring the thermal deformation the surface residual stress can be detected and evaluated. The theoretical deformation model was established, and simulation models with different surface residual stresses were constructed. A detection system was proposed to detect the blade deformation with different surface residual stresses. Results show that there was a linear relationship between the blade deformation and the surface residual stress from −636 Mpa to −1403 Mpa. [ABSTRACT FROM AUTHOR]

Three large-eddy simulations of open channel flow over a backward-facing step are performed to investigate the effect of submergence on the turbulence, hydrodynamics, and water surface deformation downstream of the step. The deformation of the water surface, the extent of the recirculation zone as well as the strength of the shear layer are a function of relative submergence. All flows downstream of the step exhibit elevated levels of turbulent shear stress and contain significant amounts of turbulent kinetic energy. The instantaneous flow features rollers immediately behind the step and horseshoe-shaped vortices shed from the shear layer, the latter being advected towards the water surface where they cause deformations. It is shown that these vortices can originate from any location along the dividing streamline; however, they contain more energy the closer to the mean attachment location they originate. [ABSTRACT FROM AUTHOR]

2D woven composites can be used in the manufacture of Radomes due to the abilities of low cost, flexible properties, formability and structural stability. By analyzing fabrics structures, a wave-transparent model was established based on surface equations of fabrics and surface deformation principle. Glass fibers were woven into plain fabrics with different parameters and covered on the surface of ellipsoid Radome model, then the woven composites were cured with epoxy resin. The validity of the proposed model was verified by an experiment with the free space method in a range of 1-18GHz. The results showed that the transmission efficiencies of composites were greater than 90% and had great relation with fibers volume content. It explains the mathematical relationship between fabrics structure and transmission efficiencies. [ABSTRACT FROM AUTHOR]

The composite box girder does not satisfy the assumption of flat section in the actual force behavior. The transverse force generated by the bending is transmitted to the shear key through the web, and then transmitted to the wing plate by the shear key. The shear deformation of the channel steel box girder web makes the shear stress of the composite box girder section unevenly distributed on the wing plate. The selection of displacement function caused by shear deformation is often unclear in physical meaning, and analysis and verification that conform to the actual deformation and stress distribution law of the structure are rarely carried out. Aiming at this problem, a microplate shear flow analysis method is proposed. Considering the influence of shear deformation, the shear lag warping displacement function of the composite beam is derived, and the displacement function is corrected according to the self-balance condition of the warping normal stress, which makes up for the defect of the unclear physical meaning of the displacement function. On the problem of solving the control differential equations. For the first time, it is proposed to use Hamiltonian theory to solve the problem, which avoids the problem of solving high-order differential equations in the classical elasticity solving method and the functional variational method based on the energy principle. The stress distribution of the composite box girder under the action of concentrated load and uniform load is analyzed. [ABSTRACT FROM AUTHOR]

Effects of surface texturing on normal contact stiffness have been investigated by experiments in previous research studies; however, there are relatively few theoretical models in this regard. This article aims to investigate the influence of surface texturing on the normal contact stiffness in theory and experiment. In the present research, a rough surface with surface texturing is divided into two parts, the textured zone and the remaining zone, and their theoretical models of normal contact stiffness are established respectively, considering surface morphology and material properties. For the textured zone, microtextures are modeled theoretically based on the three-dimensional topographic data obtained via a laser profilometer. For the remaining zone, the surface topography is characterized based on fractal theory, and a calculation model is established considering the elastoplastic deformation of surface asperities. In the experiment, the normal contact stiffness of specimens is obtained through the self-developed experimental platform. The proposed theoretical model is appropriate through the comparison of test results and theoretical predictions. The research results show that the effect of surface texture on the contact stiffness is related to the surface roughness, Sa. For the joint surfaces with Sa > 2.69 μm, the normal contact stiffness can be effectively increased through proper surface texturing. [ABSTRACT FROM AUTHOR]

Safe runway pavements are essential for the smooth landing of aircraft. Due to aircraft movements, these pavements are subjected to large dynamic loads that can cause their failure and jeopardise safety. This paper proposes the use of improved cement-based layers to enhance the performance of flexible runway pavements. The performance of such retrofitted runway pavements under both static and moving loads is investigated by experimental study and three-dimensional numerical simulations. Results indicate that the improved cement-based layers can significantly reduce surface deflections in the runways under heavy static and moving loads. Under heavy moving loads, the proposed cement-based layers can distribute the vertical stresses to the surrounding soil area, significantly reduce surface deformations and prevent failure. Findings of this research will contribute towards improved designs of runway pavements resulting in enhanced safety and failure mitigation. [ABSTRACT FROM AUTHOR]

Based on the triply periodic minimal surface (TPMS), 3D auxetic structures are successfully implemented using a dual-period function. A series of shape-controllable, dual-period deformation functions are obtained by summarising the characteristics of periodic deformation functions and applying Bezier curve fitting methods. Then, with the geometry originating from the Schwarz primitive (P) of TPMS, the periodic shape transformation of TPMS is achieved using the dual-period deformation functions. The property (negative Poisson's ratio) of the auxetic structure is investigated based on the control parameters (the TPMS c value, periodic function η, and deformation index γ). The auxetic structures can exhibit excellent 3D negative Poisson's ratio properties, and the Poisson's ratio can be effectively adjusted. Moreover, a heterostructure with positive and negative Poisson's ratio structures is obtained and applied to a stem in the hip joint. The simulation proves that the heterostructure can effectively prevent the failure of the bone implant. [ABSTRACT FROM AUTHOR]

Shanghai Pudong International Airport (PDIA), with its east side built along the coast with weak geological conditions, is prone to uneven foundation settlement due to the consolidation and compression of soil and erosion of coastal tides, affecting the safe operation of the airport. Therefore, it is crucial to conduct dynamic subsidence monitoring within the airport, especially in the runway area. 29 scenes of ascending track Sentinel-1A radar images from August 2016 to June 2018 are selected to perform surface deformation inversion based on PS-InSAR and improved SBAS-InSAR for PDIA and its around coastal area. Through cross-validation, the reliability of the time-series InSAR technique for dynamic monitoring of surface deformation of coastal zone infrastructures is confirmed. The results show severely uneven settlement. By combining the monitoring results with the local geological and hydrological dataset, the driving factors of differential deformation of the infrastructures are analyzed, including stratigraphic geological conditions, ground loadings, foundation treatment methods, water erosion, and groundwater level changes. Finally, the time-series deformation characteristics and the causes of PDIA's runway are emphasized based on the PS deformation results. This case provides a reference for the safety management of critical infrastructure in coastal areas using advanced InSAR technique. [ABSTRACT FROM AUTHOR]

This study investigates the eco-geological environmental challenges faced by Jiangxia District, a mining region in Wuhan City. By combining field surveys, literature analysis and multi-source data such as remote sensing images and on-site monitoring data, an eco-geological environment quality (EGEQ) assessment system was developed. The system consists of six indicators representing biological abundance, vegetation cover, land erosion, water abundance, surface deformation and socio-economic characteristics of the assessed area. The grey relational analysis method was utilized to calculate the weights of each indicator, and the eco-geological environment quality index (EGQI) value was obtained through the linear weighted method. The assessment results indicated a moderate grade of overall eco-geological condition in Jiangxia District between 2017 and 2021, with an 8.56% increase in the EGQI during that period. This suggests a stable and favorable eco-geo logical environment situation in the district during the specified timeframe. Synergizing radar and optical data for eco-geological quality assessment. Grey relational analysis and normalization for index weighting. Evaluating human impact with socio-economic data. Integrating surface deformation for environment evaluation. Jiangxia's eco-geological state average, yet constrained. [ABSTRACT FROM AUTHOR]

Roads are an important role in the transportation and the economy. Therefore, roads should be constructed under geometric standards to increase service life and maximize safety. However, landslides occurring around the road, especially in mountainous regions, may cause deformation on the road surface. Generally, landslide areas can be detected by measuring in more than one period. The proposed methodology investigates the landslide effect in a single period and consists of the following steps. First, a UAV collects data to generate a 3 D model. Then, an appropriate road project is designed according to the road geometric standards and 3 D model. Finally, landslides are successfully determined by comparing the appropriate road design and the current state of the road. It is found that there are road subsidence and rising areas up to 20 cm. As a result, it was determined the landslide had significant effects on the road surface with single-period UAV data. [ABSTRACT FROM AUTHOR]

To address the position offset and insufficient monitoring accuracy of surface subsidence in mining areas using the SBAS-InSAR, this study uses the MSBAS-InSAR method. However, the quality of correction results is poor owing to the ill-posed observation equation of MSBAS. Therefore, the SBAS-based decomposition method is used, which directly decomposes the ascending and descending SBAS monitored LOS results to circumvent the ill-posed problem of the MSBAS and obtain higher-accuracy 2D deformation results. A real mining area was taken as the research site and monitored using the SBAS, MSBAS, and the SBAS-based decomposition method. The accuracy and effectiveness of the surface deformation results obtained by these methods were compared and verified with the levelling data in the same period. The results show that the SBAS-based decomposition method can significantly reduce the position offset and improve the monitoring accuracy of single-track SBAS, and circumvents the ill-posed problem of MSBAS. [ABSTRACT FROM AUTHOR]

The Tibet Autonomous Region has a complex topography, and there are many difficulties in extracting its large-scale surface deformation. Traditional time-series Synthetic Aperture Radar Interferometry (InSAR) approaches are time-consuming and difficult to handle the massive growth of data in a timely manner. In this paper, a refined parallel stacking InSAR workflow for large-scale deformation fast extraction is proposed. The burst images of Sentinel-1 data were first extracted, and a series of procedures were introduced to improve accuracy, including using a short spatial baseline to mitigate topographic error, using a polynomial to fit and remove the small-scale atmospheric error, and using the joint polarization stacking method to reduce random noise. The workflow was deployed to a supercomputing system for parallel processing to improve efficiency. Using 1638 Sentinel-1 acquisitions, the surface deformation rate of the entire Tibet Autonomous Region was obtained and in good agreement with the Global Positioning System (GPS) data, with a Root Mean Squared Error (RMSE) of 3.27 mm/ year, indicating high accuracy. [ABSTRACT FROM AUTHOR]

Recently, structures, built on reclamation sites in the Eastern Black Sea region are quite remarkable. As one of them, Şenol Güneş Medical Park Arena Sport Complex, which is located in Akyazı town of Trabzon city, is one of the rare areas in Turkey. It is very important to monitor surface deformations on this type of unfamiliar and very expensive constructions for protecting human life and property and for taking necessary precautions in advance. Persistent Scatterer Interferometry (PSI), based on the analysis of time series of multiple Synthetic Aperture Radar (SAR) data, is an invaluable geodetic tool to measure surface deformations. So, in this study, it is aimed to monitor the surface deformations on the reclamation site between the dates 20/12/2016–28/01/2020 by StaMPS (Stanford Method for Persistent Scatterers)-PSI technique using 96 Sentinel-1 SAR images. For processing, integration of European Space Agency (ESA) SentiNel Application Platform (SNAP) and StaMPS programs are used. After processing, surface deformations are determined as annual velocities (millimeter(mm)/year(y)) of PS points in the reclamation area along the line-of-sight (LOS) direction between the values −9.7 mm/y and 3.9 mm/y with an average standard deviation of 0.7 mm/y. From the results, it is understood that the area demonstrates very heterogeneous deformations rates, which occur on both horizontal and vertical directions because of the diversity and being on the reclamation site of the structures. [ABSTRACT FROM AUTHOR]

Gravity Recovery and Climate Experiment (GRACE) and its Follow-On mission (GRACE-FO) have become an indispensable tool in monitoring global mass variations. However, separating GRACE(-FO) signals into its individual Terrestrial Water Storage Changes (TWSC) and surface deformation contributors, i.e. Post-Glacial Rebound (PGR), is desirable for many hydro-climatic and geophysical applications. In this study, a hierarchical constrained Bayesian (ConBay) approach is formulated to apply GRACE(-FO) fields and the uplift rate measurements from the Global Navigation Satellite System (GNSS) stations to simultaneously estimate the contribution of TWSC and PGR. The proposed approach is formulated based on a hierarchical Markov Chain Monte Carlo optimisation algorithm within a dynamic multivariate state-space model, while accounting for the uncertainties of a priori information and observations. The numerical implementation is demonstrated over the Great Lakes area, covering 2003–2017, where the W3RA water balance and the ICE-5G(VM2) and ICE-6G-D(VM5a) GIA models are merged with GRACE and GNSS data. Validations are performed against independent measurements, which indicate that the average root-mean-squares-of-differences between the PGR estimates and independent measurements reduced by 72 % after merging observations with models through ConBay. The ConBay updates, introduced to the long-term trends, as well as the seasonal and inter-annual components, are found to be realistic. [ABSTRACT FROM AUTHOR]

Surface deformation in the running-in phase is crucial because it may affect the lifetime of the mechanical system. However, deformation at this phase is very small because it occurs within the asperities and is almost undetectable using conventional mass loss or the wear depth measurement technique. This study aimed to experimentally evaluate the evolution of surface asperities in the running-in phase and gain an understanding of the factors that affect deformation. An experimental rig for the measurement of asperity deformation at a small scale was designed and fabricated for this purpose. The developed rig can quantify the progression of microgeometry asperity deformations without dismounting the sample from the rig to maintain the relative contact and avoid inaccuracy. The precision of this measurement allows online monitoring of real asperity geometry evolution and detection of small changes up to the micrometer scale. The results indicate that the asperity deformation is influenced by the initial asperity geometry. The asperity with a higher asperity slope Δa and asperity height H as well as a smaller radius R is more prone to deformation. The initial H, Rm, and Δa have a high correlation with asperity deformation Δh with high Pearson's correlation values of 0.92, 0.91, and 0.87, respectively. [ABSTRACT FROM AUTHOR]

Cu-matrix composites, with a constant graphite content but different proportions, for high-speed trains were prepared by a powder metallurgy technique. A reduced proportion pin–disc testing machine was used to study the braking performances of friction materials at different speeds. The results show that the microhardness and resistance to plastic deformation of the friction surface are significantly affected by the proper introduction of colloidal graphite. Compared with copper-plated graphite, colloidal graphite has more active surface free energy and can react readily with Fe to produce cementite. Cementite is a kind of metal compound with high strength that has a great supporting effect on the material surface. The cementite participates in the formation of a friction layer. As a result, the strength of the friction film is improved and the oxidation of Fe is reduced, leading to the generation of a friction film with strong antideformation ability. The transfer of material from the friction surface during high-energy braking is low, which stabilizes the coefficient of friction and decreases the wear volume. However, too many colloidal graphite particles results in many interfaces in the matrix and severely damage the matrix's continuity. With an increase in colloidal graphite mass fraction, the arrangement direction of the copper-plated graphite changes. When the colloidal graphite content is 1% and the copper-plated graphite content is 19%, the friction material shows a stable friction coefficient and has good tribological properties under high-speed braking at 350 km/h. [ABSTRACT FROM AUTHOR]

Plasticised poly(vinyl chloride) (PVC-P) is known to degrade rapidly and emit acidic gases and, as such, it is ideally stored separately from other materials. However, due to historic or aesthetic value, PVC-P book covers in paper-based collections cannot always be removed or replaced. There is currently a gap in the literature addressing strategies for storing PVC-P associated with paper materials. Prompted by a case study of the Chinese artist Yang Zhichao's Chinese Bible (2009)—a performance installation artwork of 3000 notebooks including approximately 1000 notebooks with PVC-P covers—three potential interleaving materials (Mylar®, Hollytex® and buffered tissue) were tested to simulate use during long-term storage. Notebooks and PVC-P book covers were purchased and assembled to model stacked storage conditions, and thermally aged at 70°C and 50% relative humidity for 130 days. Before and after ageing, samples were analysed using visual examination techniques, ATR-FTIR spectroscopy, colourimetry and weighing. It was found that all three interleaving materials lowered the probability of ink offsetting. However, cover deformation and a blotchy surface haze were more commonly observed in interleaved samples compared to non-interleaved samples. More research is necessary to identify a suitable strategy to manage PVC-P degradation in close contact storage with paper materials. This study contributes to a better understanding of the storage of plastic-covered books that may be found in libraries and archives, highlighting the complexity of conserving plastic and paper composite materials. [ABSTRACT FROM AUTHOR]

Pavement structures must guarantee safety, trafficability and comfort to highways users during its service life. The quality of these parameters is related to distresses that may occur as surface distortions, that might be caused by mechanical behaviour problems and to surface texture, which also affect highway safety. The surface texture is evaluated by parameters such as microtexture and macrotexture, related to aggregate rugosity and mixture characteristics, respectively. Both mechanical behaviour and surface texture can be affected by the compaction method of the mixture, as it affects the internal structure and the internal friction between aggregate particles, resulting in alterations in the permanent deformation resistance and surface aspects of the mixture. Hence, this paper proposed a new laboratory compaction method, using roller compaction with vibration, considering three aggregate gradations. This study evaluated the effect of the laboratory compaction method in the permanent deformation resistance and the surface texture of samples, comparing to field mixtures. The proposed compaction method presented efficiency for dense-graded mixture. The mixture's performance regarding mechanical behaviour and surface texture according to the compaction method variation was also dependent on the aggregate gradation. Mixtures with a discontinuity on the gradation presented a negative impact due to the vibration process. [ABSTRACT FROM AUTHOR]

The key objective of the present study is to estimate the surface displacement and to understand/monitor the active deformation pattern in the Kachchh region post the 2001 Bhuj Earthquake by implementing the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) and Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques. We employed the ENVISAT ASAR (15 images), ALOS PALSAR (6 pairs) and SENTINEL-1A (117 images) data sets acquired during the periods 2003–2005, 2007–2009, and 2016–2020 respectively. The PSI results of the Envisat dataset reveals that the Kachchh mainland region has undergone an average surface deformation of ± 22 mm/yr during 2003–2005. The maximum displacement observed from the ALOS PALSAR data sets (Window-1 to 6) during the period 2007–2009 is ∼ ± 1.2 cm. Further, the ground displacement observed from the Sentinel-1A dataset during the period 2016–2020 is ±16 mm/yr for the west-central region and 6 mm/yr uplift and 8 mm/yr subsidence in the eastern Kachchh mainland region. Surprisingly, high rate of deformation is detected towards the Pachham Island, Banni, Rann and the eastern region of the Kachchh after the 2001 Bhuj event. Correlating the results of different data sets, it is concluded that the deformation is high near the vicinity of the fault zones indicating the tectonically active nature of the faults. From the obtained results, we infer that, post the 2001 Bhuj earthquake, the surface displacement in the Kachchh mainland region is escalated till 2009 which is due to continuous aftershock activity and then started declining because of the ongoing seismic settlement. The acquired deformation rates are correlating well with the GPS derived displacement rates. Further, our results will assist in accurately demarcating the extent of the fault zones and also helps in precisely marking the areas undergoing active deformation, which will aid in micro zonation studies, mitigation planning and also for the preparation of an active tectonic map for the region. [ABSTRACT FROM AUTHOR]

The study involves developing a framework of research methodology for enhancing the capability of spaceborne integrated DInSAR and PSI approach for better detection, monitoring, and analysis of land surface deformation in the underground mining environment. First component of the framework involves pre-feasibility assessment of the integrated approach followed by selecting suitable InSAR data sets considering three significant parameters, i.e., terrain, deformation, and system characteristics. The other essential components are preprocessing of the selected & acquired InSAR data for its quality check, the scheme for better detection as well as monitoring of mining subsidence trough(s) using Coherent Small Baseline-DInSAR Time Series (CSB-DTS), scheme for better in-depth monitoring of detected and undetected mining subsidence trough(s) using PSI, and result validation & analysis. Effectiveness of the proposed framework has been validated in the assessment of subsidence due to underground mining activities in one of the largest copper-ore producing belts in India, Khetri Copper Belt. [ABSTRACT FROM AUTHOR]

Distributed scatterer interferometry (DS-InSAR) is an important time-series technique of surface deformation monitoring. The accuracy of the results highly depends on the density of DS, which is mainly influenced by synthetic aperture radar (SAR) image resolution and land cover. In this work, firstly, we use split spectrum technique to enable construction of SAR images with different bandwidth (i.e. different resolution). With the land-cover map as classification basis and mean coherence as DS selection index, we quantitatively analyse the behaviour of DS pixel density on different resolution SAR images and three land-cover types. We find that the DS density increases linearly with the increase of SAR system bandwidth, but the linear coefficient decreases with the increase of mean coherence. Secondly, we extend the coherence framework proposed by Zebker in 1992 to establish a model of relationship between mean coherence and bandwidth. The DS density by three land cover and different bandwidth SAR images was predicted by this model. When the mean coherence threshold is set to 0.4, the prediction model can agree with empirical results within 50% difference, and rather closer on impervious surface. [ABSTRACT FROM AUTHOR]

This paper presents results of a solitary wave propagating over a submerged horizontal plate based on a non-hydrostatic model. A high-resolution advection scheme is employed based on a second-order flux-limiter method. The model is first validated by comparing numerical results with recently obtained measured data. Then, a series of simulations are carried out to investigate the effect of the plate length on the characteristics of vortex shedding and evolution. With the increase in the length of the plate, more dominant vortical structures induced by the solitary wave with the same wave height can be identified near the lee side of the plate. There are two separate positive vortex shedding from the lower corner of the plate near the lee side, which are not presented in experiments. The secondary positive vortex leads to the water surface deformation for the case that is close to the limit when wave breaking occurs. [ABSTRACT FROM AUTHOR]

Multitemporal interferometric synthetic aperture radar (MT-InSAR) technique is an important approach for surface deformation monitoring. Nonlocal adaptive multilooking approach has potential benefits for the filtering and coherence estimation in the data preprocessing steps of MT-InSAR technique. The kernel of nonlocal adaptive multilooking approach lies in the selection of statistically homogeneous pixels (SHPs). Various amplitude-based strategies, such as DespecKS and its variations, have been proposed for selecting SHPs. However, the detection rates of these methods are usually unsatisfactory in the case of small data sets. To overcome this limitation, SHPs are selected based on the adaptive joint data vector, which encompasses both time dimensional samples and spatial information. In this letter, the outliers of the time dimensional samples are removed first based on a revised boxplot method. Additionally, image segmentation and L1 norm are both introduced to adaptively construct joint data vector in the preset window. Experiments on five TSX images are used to verify the reliability and efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

With the development of modern industry, rotary lip seals are applied to more complex working conditions. For lip seals with larger or smaller radial force and lip seals with incomplete motion such as robot joint seals, it has been found that the traditional reverse pumping theory has a certain scope of application. Therefore, in this study, a mixed lubrication model based on deterministic surface microdeformation is proposed to calculate the tangent deformation of lip surface asperities without presetting the reverse pumping effect and then assess the effect of reverse pumping behavior. The radial force, contact width, friction torque, leakage rate, static contact pressure, and tangential deformation were either measured or calculated. The results obtained by this study can be used as guidelines for the design and optimization of rotary lip seals. [ABSTRACT FROM AUTHOR]