Magnitude Of Deformation Research Articles

Limitations of earthquake coseismic deformation measurements using InSAR

ABSTRACT Interferometric Synthetic Aperture Radar (InSAR) is commonly used to measure earthquake coseismic deformation. However, InSAR cannot be used to effectively measure all types of coseismic deformation, and it is influenced by numerous factors. Currently, for the limitations of InSAR coseismic deformation measurement, only empirical judgements are used to address these issues, and quantitive descriptions are lacking. To determine the limits of coseismic deformation that can be measured using InSAR, we assessed the effects of satellite parameters, earthquake magnitude, and earthquake depth on such measurements through coseismic deformation simulations and fault parameter traversals. By comparing the absolute deformation magnitudes, we identified the fault parameters that were most and least sensitive to coseismic deformation measurements using InSAR. We then quantitatively analysed the upper and lower limits of earthquake magnitude and depth for InSAR coseismic deformation measurements. The lower limit was determined by comparing noise and deformation, whereas the upper limit was determined from the phase gradient ambiguity. We used the least squares method to derive an empirical equation that can be used to screen earthquake catalogues for further inversion with InSAR measurements. We found that coseismic deformation measurements using satellites are limited by their sensitivities to fault strike, rake, and dip angles. Additionally, the smallest earthquake magnitude that can be measured by InSAR varies with depth. These findings can be used to improve our understanding of the limitations and capabilities of InSAR for measuring coseismic deformation.

Patient-Specific Rods vs Traditional Rods in Surgical Correction of Adult Spinal Deformities: A Case-Matched Study.

Patient specific pre-contoured rods (PSRs) represent a relatively new technological development aimed at improving surgical outcomes and reducing complications in adult spinal deformity surgery. To date, only a limited number of studies have been published comparing PSRs with traditional spinal rods. In this paper, we compare the surgical, imaging, and clinical outcomes of PSRs and traditional spinal rods in a single-center case-matched study. Thirty cases of adult spinal deformities (ASD) were retrospectively analysed. These included 10 patients who were operated on using UNiD™ (Adaptive Spine Intelligence, MedTronic, Minneapolis, MN, USA) PSRs and 20 operated on using traditional rods from January 2023 to August 2023. Minimum post-surgical follow-up was 6 months. General demographics and standard radiographic parameters, as well as Scoliosis Research Society (SRS)-22, Oswestry Disability Index (ODI) and Short Form Health Survey (SF-12) Scores, were measured at pre-operative examination and at 6-month follow-up. Follow-up imaging data were compared with software-planned correction goals. Intra-operative data and complications were also recorded. Patients in the two groups were matched in terms of age, body mass index (BMI), sex, type and severity of spinal deformity. The magnitude of the coronal deformity (p = 0.812) and preoperative sagittal imbalance (p = 0.845) were similar between the two groups. The number of fused levels (p = 0.439), osteotomies (p = 0.188), implant density (p = 0.880), and surgery duration (p = 0.299) were similar between the two groups. Sagittal correction goals set during preoperative planning were achieved in the PSRs group, with the exception of pelvic tilt (PT) (p = 0.042). In contrast, PT (p = 0.040), L1-S1 lordosis (p = 0.032) and global tilt (GT) (p = 0.001) remained significantly undercorrected in the control group at 6-month follow-up. Clinical outcomes (ODI and SF-12 Scores) and complication rates were similar between the two groups. The use of PSRs improves the achievement of better post-operative spinopelvic alignment in adult spinal deformity surgery. Moreover, no significant differences were noted in terms of complications, operative times, and clinical outcomes compared to traditional spinal rods at 6-month follow-up.

Study of residual stress and residual deformation of T-joints by continuous simultaneous double-sided welding

This paper investigates both the magnitude and distribution of temperature field, residual stress and deformation of DH36 steel fillet welded T-joints through the numerical simulation method. A thermal elastic-plastic finite element analysis is performed to investigate the heat transfer and deformation mechanisms during the welding process, employing a DFLUX subroutine developed in ABAQUS based on the double-ellipsoidal heat source model. The effects of welding speed and power on residual stress and deformation are further investigated. The finite element simulation results show good agreement with experimental measures regarding temperature distribution, melt pool morphology, residual stress, and deformation distribution. The results show that welding speed and power significantly affected the temperature variation during the welding process, which further influence the distribution of residual stress and residual deformation. The results indicate that high power at low welding speeds producing high temperatures leads to bottom fusion, while low power at high welding speeds resulted in insufficient fusion depth. Therefore, selecting appropriate welding speed and power is crucial for ensuring weld quality.

Deformation of Threaded Metal – Composite Couplings Under the Action of Gas-Dynamic Loads

The combination of metal and composite in threaded couplings increases the reliability of the structure operating under conditions of intensive internal pressure. Strength analysis of threaded metal – composite couplings based on the application of modern finite element modeling methods at the stage of design documentation development allows to create more efficient structures that better meet the operational requirements. The strength of threaded couplings of cylindrical shells made of composite material and metal under the action of gas-dynamic internal pressure is analyzed in this paper. A methodology for numerical study of the problem in Ansys / Explicit Dynamics software package is proposed. Detailed modeling of threaded couplings is used. The developed model takes into account the following: dependence of material properties on ambient temperature; nonlinear relations between the components of stress and strain tensors in metal elements, orthotropic properties of composite materials; peculiarities of contact interaction in the zones of threaded couplings of prefabricated shell elements made of different materials. The stress state of a cylindrical structure with a central shell made of carbon fiber-reinforced plastic or fiberglass and with steel shells at the edges, loaded with gas-dynamic internal pressure with a maximum value of 20 MPa at a maximum ambient temperature of 100 °С was studied. It was obtained that plastic deformations are concentrated on the edges of the threaded couplings of steel shells. At the same time, the magnitude of plastic coupling deformations with the inner metal shell is an order of magnitude higher than for couplings with the outer metal shell. The magnitude of plastic deformations in couplings with an inner metal shell is twice less when using fiberglass than when using carbon fiber reinforced plastic. Localization of critical stresses was observed only in metal shells at threaded couplings. In this case, in the thread zone they are within the elasticity limits, and the stress state of the FRP shell is not critical. No local material failure was observed in the structure.

The influence of Kitchon-RCAA on biomechanics of maxillary tissues based on indirect action: A finite element analysis.

This paper creates 3D models of Kitchon Root Controlled Auxiliary Archwire (Kitchon-RCAA) with different material properties and assembles them onto the main archwire equipped with brackets. By setting different loading methods and conducting Finite Element Analysis (FEA), the range of Orthodontic Torque/Support Force (OT/SF) values can be obtained. From the obtained values, it can be seen that changes in material properties have a significant impact on the mechanical properties of Kitchon-RCAA. When the properties of the Kitchon-RCAA material change two or more times, the mechanical values generated by Kitchon-RCAA cannot be directly added from two or more separate changes in the properties of the material. Therefore, it is necessary to simulate the model after each parameter change to obtain new results. And then the maxillary bio-model is reconstructed in reverse based on Cone Beam Computerized Tomography (CBCT) images. The biomechanical data equivalent to the mechanical mechanics generated by the root control assisted archwire is also added to the corresponding tooth positions, making indirect orthodontic behavior of Kitchon-RCAA on teeth possible. From the obtained results, it can be seen that the von Mises stress and total deformation magnitude for both normal teeth and corresponding Periodontal Ligament (PDL) position show a stable trend, while the Right Cuspid (R-C) and corresponding PDL with malformed root have a large stress concentration and may have a mold penetration problem. Overall, this paper not only analyses the mechanical behavior of the Kitchon-RCAA, this article not only analyzed the mechanical behavior of Kitchon-RCAA, but also its effect on the indirect biomechanical behavior of the teeth and PDL. And in combination with simulation result nephograms, it also enables predictability and visualization of orthodontic results. This helps dentists to provide safer and more reliable individualized orthodontic treatment plans for patients.

Ship Hull Steel Plate Deformation Modeling Based on Gaussian Process Regression

The linear heating and formation of steel plates is one of the most critical technologies in shipbuilding. Excellent technology not only provides good hydrodynamics for the hull but also affects the whole hull construction cycle and cost. In the heating and formation of a steel plate, the material, size, and thickness of the steel plate; heating temperature; heating position; and many other factors affect the formation of a steel plate. It is a very difficult process to know the influence relationship between various factors. In this study, a steel plate model is established by the Gaussian regression method, which can predict the steel plate deformation according to the selected steel plate material, size and thickness, heating temperature, and heating position. The accuracy of the model was evaluated, and the Gaussian process regression model has a better accuracy compared to other machine learning algorithm models. Finally the model visualization; designing the UI; selecting the steel plate material, size, and thickness; and inputting the heating temperature, the deformation magnitude, and stress magnitude of the steel plate can be obtained. The model can provide guidance to field workers for the heating and formation of hull steel plates and achieve efficient and fast formation of target steel plates.

Asymmetric fluctuations and self-folding of active interfaces

We study the structure and dynamics of the interface separating a passive fluid from a microtubule-based active fluid. Turbulent-like active flows power giant interfacial fluctuations, which exhibit pronounced asymmetry between regions of positive and negative curvature. Experiments, numerical simulations, and theoretical arguments reveal how the interface breaks up the spatial symmetry of the fundamental bend instability to generate local vortical flows that lead to asymmetric interface fluctuations. The magnitude of interface deformations increases with activity: In the high activity limit, the interface self-folds invaginating passive droplets and generating a foam-like phase, where active fluid is perforated with passive droplets. These results demonstrate how active stresses control the structure, dynamics, and break-up of soft, deformable, and reconfigurable liquid-liquid interfaces.

Оценка результатов хирургического лечения детей с деформацией позвоночника и грудной клетки с применением навигационной установки

Idiopathic scoliosis (IS) accounts for 2% to 5% of cases in orthopedic pathology. Surgical treatment of severe, rigid IS forms remains an important and pressing problem. The purpose of this research was to evaluate the efficacy and safety of the surgical correction method of severe kyphoscoliotic deformity of the thoracic spine in children with the use of the active optical three-dimensional computer navigation technology. Materials and methods used: a retrospective, single-center cohort study of the surgical treatment results of 30 children aged 14 to 18 y/o with grade 4 IS was conducted with V (C) Level of Evidence. The inclusion criteria were as follows: the scoliotic deformity magnitude of over 80°, simultaneous discopphysectomy, mobilizing dorsal osteotomies and deformity correction with a multi-support metal structure. Results: the scoliosis magnitude in the preoperative period was 100.5° (min 82; max 130; SD=13.21), after surgery 27° (min 4; max 47; SD=12.53). Pairwise comparison demonstrated statistically significant differences (p=0.013). The kyphosis magnitude in the preoperative period was 39.4° (min 3; max 61; SD=16.61), after surgery - 37.7° (min 3; max 49; SD=6.59). The abovementioned data comparison demonstrated the absence of statistically significant differences (p=0.154). The vertebral rotation magnitude in the preoperative period was 35.5° (min 20; max 60; SD=8.73), after surgery - 20° (min 9; max 32; SD=6.54). When comparing the results, statistically significant differences were revealed (p=0.010). Neurological disorders after the surgical interventions were not noted in patients included in the study. Conclusion: the use of the method of surgical correction of severe kyphoscoliotic deformity of the spine from a combined approach using active optical three-dimensional computer navigation technology allows the complete correction of the spinal deformity, indirectly improving both the shape and the size of the chest and restoring the frontal and sagittal profiles of the spine.

Quantifying articulatory variations across phonological environments: An atlas-based approach using dynamic magnetic resonance imaging.

Identification and quantification of speech variations in velar production across various phonological environments have always been an interesting topic in speech motor control studies. Dynamic magnetic resonance imaging has become a favorable tool for visualizing articulatory deformations and providing quantitative insights into speech activities over time. Based on this modality, it is proposed to employ a workflow of image analysis techniques to uncover potential deformation variations in the human tongue caused by changes in phonological environments by altering the placement of velar consonants in utterances. The speech deformations of four human subjects in three different consonant positions were estimated from magnetic resonance images using a spatiotemporal tracking method before being warped via image registration into a common space-a dynamic atlas space constructed using four-dimensional alignments-for normalized quantitative comparisons. Statistical tests and principal component analyses were conducted on the magnitude of deformations, consonant-specific deformations, and internal muscle strains. The results revealed an overall decrease in deformation intensity following the initial consonant production, indicating potential muscle adaptation behaviors at a later temporal position in one speech utterance.

Localised External Blast Response of CFRP Retrofitted Steel Cylindrical Tubes

Abstract This paper presents the key outcomes derived from a series of experiments and numerical simulations aimed at understanding how carbon fibre reinforced polymer (CFRP) retrofitted cylindrical steel tubes respond to localised external blast loads. The blast tests were conducted using a ballistic pendulum on both as-received and retrofitted tubes, employing various configurations of CFRP retrofitting. The as-received mild steel cylindrical tubes had an outer diameter of 101.6mm, a wall thickness of 2.0mm, and spanned a length of 400mm. The cylindrical steel tubes were retrofitted with CFRP, stacked with four plies of fibre in four different arrangements. The tubes were subjected to lateral loading at the mid-span using plastic explosive (PE4) discs, each with a consistent diameter of 33mm, detonated at a stand-off distance of 13mm. The study investigated the influence of impulse (or charge mass) and the orientation of CFRP retrofitting on the structural response and failure behaviour of retrofitted tubes. The experiments demonstrated various combined CFRP failure modes resulting from localised blast loads, including metal-CFRP debonding, interlaminar delamination, and fibre rupture, particularly in the vicinity of the localised blast zone. Additionally, the findings indicated that CFRP tube retrofitting enhanced blast loading capacity, leading to reduced mid-point deflections compared to as-received tubes. Moreover, the results highlighted the effectiveness of CFRP retrofitting in increasing the threshold load for tearing failure in the steel tubes. The simulations from LS-Dyna were validated against the structural response and magnitude of deformation obtained from the experiments showed good correlation.

Mathematical models of system of measure of pressure variation in combustion chambers of engines

In this paper the mathematical modelling of a mechanical system designed to control changes in the pressure of the working medium in aircraft engines and consisting of a pipeline and a pressure sensor is carried out. The pipeline is necessary to take the sensor to some distance from the engine in order to mitigate the impact of high temperatures and vibration accelerations on the sensitive element of the sensor, which is an elastic plate. The system takes into account the aerohydrodynamic and thermal effects of the working medium on the plate. Asymptotic equations of aerohydrodynamics in the models of compressible and incompressible medium are used to describe the working medium motion in the pipeline. Both linear and nonlinear models of a deformable solid body are proposed to describe the plate dynamics. When using the compressible medium model, the solution of the problem is reduced to the study of an equation with a deviating argument. To solve the problem using the incompressible medium model, Fourier and Galerkin methods are applied. As a result, for both models the solution of the problem is reduced to the study of ordinary differential equations relating the magnitude of pressure in the motor with the magnitude of deformation of the sensing element, which can be used to control the mode of operation of the motor. The solution of these equations is found with the developed software program using standard functions of Mathematica 12.0. The paper was presented at PhysCon2024.

Unveiling subsidence patterns: Time series analysis for land deformation investigation in the west-Qurna oil field, Iraq

Land subsidence is a worldwide geological and environmental risk caused by natural occurrences and human actions. Its effects include a range of socio-economic, environmental, and hydrogeological consequences, such as damage to infrastructure like buildings, roads, bridges, and pipelines, as well as increased flooding and reduced groundwater storage capacity. Due to these diverse impacts, it is crucial to monitor the spatial and temporal scope of land subsidence. This study presents an investigation into land subsidence within the West-Qurna oil field, a large oil reservoir situated in Iraq's Basrah governorate. The study employs Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) analysis from the European Space Agency Sentinel 1A over six years, from June 2017 to May 2023. The Stanford Method for Persistent Scatterers (StaMPS) has been utilised to assess the scale and magnitude of land deformations in this region. Results revealed a notable subsidence within the central urban area of the oil field, forming an ellipsoidal subsidence bowl spanning 86 km2. The peak subsidence rate is identified at −13.2 ± 0.4 mm/yr within this bowl, with a cumulative vertical displacement of 75 mm throughout the six-year observation period. Furthermore, uplifting phenomena are also detected at the study area's peripheries, reaching a maximum rate of 12 ± 0.4 mm/yr and a cumulative shift of 54 mm. Temporal analysis showcases a significant alteration in subsidence rates, with rates of −18 mm/yr observed between 2017 and 2020, followed by −5 mm/yr post-2020. This change is attributed to COVID-19-related oil production reductions enacted by the government to boost prices. Our analysis points toward oil extraction as a probable primary driver of subsidence in the studied area, although a deeper probe into the impact of groundwater extraction for reservoir injection remains essential.

Cardiovascular remodelling and reverse remodelling during pregnancy and postpartum: Looking at the right side

BackgroundConsidering the limited information available on right cardiac remodelling during gestation, we aimed to characterise the right cardiovascular (CV) remodelling and reverse remodelling (RR) induced by pregnancy and postpartum, respectively, and the impact of perinatal CV risk (CVR) factors on these processes. MethodsThis prospective cohort was recruited at two tertiary centres during 2019–2022, including 51 healthy pregnant women and 79 with perinatal CVR factors. Participants were evaluated by transthoracic echocardiography during pregnancy (1st[1T] and 3rd[3T] trimesters) and postpartum (one-month[PP1], six-months[PP2], and one-year postpartum[PP3]). Generalised linear mixed-effects models were used for statistical analysis. ResultsSimilar enlargement of the right atrium (RA) and right ventricle (RV) dimensions was observed throughout pregnancy, normalising at PP2 values similar to PT1. This anatomical postpartum recovery was accompanied by an increase of RV global longitudinal strain, being statistically significant in perinatal CVR group. Interestingly, at 3T, this group revealed lower RV and RA strain compared to healthy participants. Despite both groups maintained preserved RV systolic function from 1T to PP3, a significant reduction of TAPSE and tricuspid S’ velocity was observed at PP1. Concomitantly, all participants showed a significant increase of E/A at the same time-point, suggesting the recovery of diastolic deterioration seen from 1T to 3T that was persistingly higher in the perinatal CVR group througout the postpartum. Constant pulmonary artery systolic pressure (PASP) was documented throughout follow-up time, showing consistently higher values in the perinatal CVR group. All these echocardiographic index changes were within the normality range. ConclusionThis study described subtle right cardiac changes within the normal/physiological range, recovering six-months after delivery. Coexisting perinatal CVR factors seem to affect the magnitude of RV diastolic function changes, PASP and myocardial deformation without any impact on other RV systolic function indexes.

Dynamic parallel traction theoretical model for the application and validation in femoral neck fractures - a finite element analysis

Study objectiveThis study aims to validate the application effects of a novel theoretical model of dynamic parallel traction in the treatment of femoral neck fractures through three-dimensional finite element analysis. By simulating the femoral neck fracture model, we explore the promotional effect of dynamic parallel traction on fracture healing. MethodA digital 3D femur model was constructed using high-resolution computed tomography data of the lower limbs of a 70-year-old elderly subject. An axial compression of 500N was applied at different traction angles (0°, 10°, 20°, 30°, 40°, 50°). The equivalent stress distribution and deformation of the femur geometric model were calculated at each angle under the six α angles. Statistical analysis was performed using One-Way ANOVA. ResultsAt the parallel angle (α = 0°), the maximum stress on the entire femur occurred at the trochanteric fossa, with a value of 7.945 MPa (α = 0°). The maximum deformation was at the fovea capitis, with a value of 104.13 mm (α = 0°). As the traction angle gradually increased (α = 10°, α = 20°, α = 30°, α = 40°, α = 50°), the maximum stress shifted gradually to the medial cortex of the femoral shaft, with values of 11.236 MPa (α = 10°), 15.196 MPa (α = 20°), 19.263 MPa (α = 30°), 23.149 MPa (α = 40°), and 26.311 MPa (α = 50°). The maximum deformation remained at the fovea capitis but increased to 131.87 mm (α = 10°), 181.96 mm (α = 20°), 228.2 mm (α = 30°), 271.15 mm (α = 40°), and 307.41 mm (α = 50°). One-Way ANOVA revealed that traction angle significantly influenced the stress distribution (F = 4.419, p = 0.0022) and deformation magnitude (F = 4.023, p = 0.0040) at the proximal femur, indicating that traction angle is a critical factor affecting stress distribution and deformation. ConclusionWith the increase of the traction angle, the mechanical properties of the proximal femur decrease, indicating an increased risk of non-union and complications. Additionally, the study proves the effectiveness of the “dynamic parallel traction” theory.

When to change needles during neuromodulator injections-An electron-microscopy investigation into needle tip deformation.

Neuromodulator injections are minimally invasive procedures performed across the globe. Despite their ubiquity, there is a dearth of information on whether and how needle tips used for neuromodulator procedures are deformed after repeated injections. We investigated the magnitude of needle tip deformation following sequential injection passes (3×, 5×, and 10×) during facial neuromodulator injections with three commonly used needle sizes (30G, 31G, and 32G). Neuromodulator was administered for four different aesthetic indications. Each collected needle was mounted and imaged in a Philips XL-30 Scanning electron microscope. Images were processed using ImageJ photo analysis software. Forty-five needle tips were investigated. When comparing the facial regions of interest, a statistically significant difference in deformation percentage was found when injecting 10× (p = 0.044) with greatest damage after injecting the glabella (38.4%), followed by lateral canthus (27.9%), forehead (27.5%), and midface (23.1%). Independent of facial region targeted, the mean percentage of needle deformation at 3× was 14.8%, at 5× 19.6%, and at 10× 29.2% with p < 0.001. Smaller needle size corresponded to smaller percentage of damage. Exchanging needles after more than five injection passes will minimize needle deformation and likely increase injection precision.

Computational design of 4D printed shape morphing lattices undergoing large deformation

Abstract In 4D Printing, active materials are embedded in structures such that the application of an external stimulus, usually coming from the environment, results in a structural response. To design structures that achieve a targeted shape change for a defined stimulus, also known as shape morphing, the material distribution and structure needs to be tuned. However, the computational design of such material distributions and structures is a challenging task and remains, despite recent advances, unable to fully leverage the entire design freedom offered by state-of-the-art 4D printing technology. Notable gaps concern the handling of large and complex deformations, the high computational cost, and the exploration of the design space by the generation of alternative solutions. In this article, a method is presented to fill this gap. First, an artificial neural net is trained that represents a deformation map that occurs during actuation. Then, a shape morphing truss is designed that achieves this deformation during actuation. The method is used to solve four shape morphing problems, where superior capabilities are demonstrated in terms of magnitude and complexity of deformations that can be handled, efficient generation of alternative solutions and versatility. Due to these capabilities, the method enables exploration of the full potential of 4D printing technology to create stimuli-responsive, multifunctional structures.

On the physical-mechanical and tribotechnical properties of antifriction carbon fiber based on a modified thermosetting matrix

The physical-mechanical and tribological properties of anti-friction carbon fiber plastic UGET based on low-modulus carbon fabric “Ural T-15R” have been studied in order to increase the magnitude of the ultimate deformation and reduce the elastic modulus through the use of a modified thermosetting matrix ET-4 instead of the traditionally used ET-2.Modes of polymerization and of heat treatment of epoxy binders were selected considering the results of the experiments. Prototypes of prepregs were obtained by solution impregnation on the UPST-1000M line and then processed into PCM by hot pressing. Laboratory samples were made and physical and mechanical tests were carried out to determine the ultimate strength under compression, shear and bending stress under destruction, as well as Charpy impact strength. Steel 20Kh13 and oxidized titanium alloy PT-3V were used as counter body rollers to determine carbon fiber tribosets.It was shown that carbon fiber samples based on chemically modified binder ET-4 with two-stage polymerization and heat treatment mode in the range of 90°C to 180°C both have better physical-mechanical and tribotechnical properties, in contrast with the analogue with a three-stage mode and carbon fiber carbon heat at friction over 20Kh13 steel and oxidized titanium alloy PT-3V.

High‐speed escape jumps in haptophytes: Mechanism and triggering fluid signal

AbstractSome planktonic organisms can remotely sense and evade predators by powerful escape jumps. Remote perception typically happens through the fluid disturbance generated by the approaching predator or its feeding current. In copepods and ciliates with mechanosensors, the perception and jump mechanisms are well understood. But how some flagellates perceive the fluid disturbance and achieve similar relative speeds with only two flagella is less explored. Here, we examined the ability of three haptophytes, Chrysochromulina simplex, Prymnesium polylepis, and Prymnesium parvum, to sense and evade the fluid disturbance generated by the feeding current of a copepod nauplius. Chrysochromulina simplex has a long haptonema (14 cell diameters), while the haptonema of the two other species are shorter (1 and 0.5 cell diameters). Only C. simplex responded to the fluid disturbance by fleeing at high speeds. The jump mechanism consists of two phases: the rapid coiling of the haptonema that pulls the cell about two cell diameters in the direction of the haptonema, followed by flagellar reversal and high‐speed swimming (70 cell lengths per second) in the opposite direction. We rationalize cell displacements and escape speeds from haptonema and flagellar kinematics and fluid dynamics. Using a microfluidic channel, we demonstrate that the component of the fluid signal that triggers the jumps is the maximum deformation rate rather than the magnitude of deformation. High‐speed escape jumps may be an avoidance mechanism evolved by haptophytes with long and coiling haptonema, while species with shorter haptonema may use other defense mechanisms, such as stealth and toxicity.

Deformation Monitoring and Analysis of Baige Landslide (China) Based on the Fusion Monitoring of Multi-Orbit Time-Series InSAR Technology.

Due to the limitations inherent in SAR satellite imaging modes, utilizing time-series InSAR technology to process single-orbit satellite image data typically only yields one-dimensional deformation information along the LOS direction. This constraint impedes a comprehensive representation of the true surface deformation of landslides. Consequently, in this paper, after the SBAS-InSAR and PS-InSAR processing of the 30-view ascending and 30-view descending orbit images of the Sentinel-1A satellite, based on the imaging geometric relationship of the SAR satellite, we propose a novel computational method of fusing ascending and descending orbital LOS-direction time-series deformation to extract the landslide's downslope direction deformation of landslides. By applying this method to Baige landslide monitoring and integrating it with an improved tangential angle warning criterion, we classified the landslide's trailing edge into a high-speed, a uniform-speed, and a low-speed deformation region, with deformation magnitudes of 7~8 cm, 5~7 cm, and 3~4 cm, respectively. A comparative analysis with measured data for landslide deformation monitoring revealed that the average root mean square error between the fused landslide's downslope direction deformation and the measured data was a mere 3.62 mm. This represents a reduction of 56.9% and 57.5% in the average root mean square error compared to the single ascending and descending orbit LOS-direction time-series deformations, respectively, indicating higher monitoring accuracy. Finally, based on the analysis of landslide deformation and its inducing factors derived from the calculated time-series deformation results, it was determined that the precipitation, lithology of the strata, and ongoing geological activity are significant contributors to the sliding of the Baige land-slide. This method offers more comprehensive and accurate surface deformation information for dynamic landslide monitoring, aiding relevant departments in landslide surveillance and management, and providing technical recommendations for the fusion of multi-orbital satellite LOS-direction deformations to accurately reconstruct the true surface deformation of landslides.

Crack tip stress intensification in strain-induced crystallized elastomer

Natural rubber (NR) exhibits strain-induced crystallization (SIC), enhancing tearing strength and crack resistance. However, the reinforcement mechanism along with nonuniform strain around a crack tip remains unclear. We reveal the nonuniform stress field around a crack tip using the DIC-based deformation field data and a hyperelasticity approach. A hyperelastic strain energy density function (W) is derived to be able to replicate stress-strain data across various deformations, encompassing equal and unequal biaxial, uniaxial, and pure shear stretching. These data cover the full range and magnitude of deformations around the crack tip. SIC significantly impacts the singular behaviors of strain and stress near the crack tip, causing a pronounced stress increase and strain decrease within the SIC zone that extends up to approximately 100 μm away from the crack tip. This results in a distinct crossover in singularity power-law index between the SIC zone and the fully amorphous zone. With increasing crack opening, the stress upturn intensifies, and the crossover shifts away from the crack tip due to SIC zone enlargement and local crystallinity increase. These findings deepen our understanding of the physics of SIC near crack tips and its reinforcement mechanism in strain-induced crystallizable soft solid materials.