Similar Deformation Research Articles

Comparative advantages of activities with lumbosacral preservation for adult spinal deformity surgery: a retrospective Japanese cohort study.

Retrospective cohort study. This study aimed to demonstrate the advantages of preservation of the lumbosacral segment (LSS) in adult spinal deformity (ASD) surgery. Sacroiliac foundation enables sufficient restoration in ASD surgery; however, it could result in poor mobility. Thus, whether LSS provides better activities is still unknown. Among 399 patients who underwent ASD surgery, 62 (≥5 levels fused, >2-year follow-up) underwent fusion from T9-10 to L5 (group L, n=21) or to S2-alar-iliac (group S, n=41). Spinal alignments, Scoliosis Research Society (SRS)-22 scores, performance of activities (clipping toenail, wiping buttock, and wearing socks), proximal and distal junctional failure (PJF+DJF), rod fractures (RFs), and overall revision rates (RRs) were compared between the groups. Group L included younger patients and had longer follow-ups when compared with group S. Although the preoperative pelvic incidence and SRS sagittal modifiers were better in group L, postoperative spinal restorations were nonpathological in both groups. Both groups showed similar deformity progression at the 2-year follow-up; however, group L had lower SRS-22 pain scores. Although "wiping buttocks" did not differ between the groups, the performance of "clipping toenails" and "wearing socks" was poorer in group S at 2 years (possible, group S; 40% vs. group L; 85%-90%). The RRs did not differ between the groups; however, the PJF+DJF rate was higher in group L. DJF was not observed in group S, but occurrence of RFs was noted. Although poorer SRS-22 pain scores might be related to lumbosacral mobility, sufficient restoration, equivalent deformity progression, and similar RRs with better activity imply that lumbosacral preservation should be considered in younger patients with moderate deformities.

Influence of Binding Energies on Required Process Conditions in Aerosol Deposition

AbstractWith the high interest in aerosol deposition in order to form high-quality coatings by solid-state impact, there is an increasing demand for developing general guidelines to estimate needed particle velocities and thus process parameter sets for successful deposition of ceramic materials. By using modeling approaches, rather different material properties in first instance can be expressed in terms of binding energies. Needed velocities for possible bonding can then derived by impact simulations and compared to experimental results from the literature. In order to study the role of binding energy on the impact behavior of ceramic particles in aerosol deposition, a molecular dynamics study is presented. Single-particle impacts are simulated for a range of binding energies, particle sizes and impact velocities. The results show that increasing the binding energy from 0.22 to 0.96 eV results in up to three times higher characteristic velocities corresponding to the threshold of bonding or grain size-dependent fragmentation of the particles. However, regardless of the binding energy, exceeding the characteristic velocities results in a similar deformation and fragmentation pattern. This allows for a general representation of the impact behavior as a function of normalized impact velocity for different ceramic materials. Apart from dealing with prerequisites for bonding of different materials by aerosol deposition, this study could also be generally relevant to the high-velocity deformation behavior of ceramics with different grain sizes.

Ultrasonic fatigue of superelastic Nitinol and in situ synchrotron observation of strain and damage

Superelastic Nitinol was tested at ultrasonic frequency in the high and very high cycle fatigue regime. Thin sheet specimens were initially preloaded to mimic crimping and deployment of Nitinol implants, which lead to a sample in a multi-phase state with martensitic phase in the middle and adjacent zones with austenitic phase. In situ synchrotron X-ray diffraction (XRD) was used to monitor cyclic strains over an entire ultrasonic cycle, and to compare the results with low frequency loading. Both austenitic and martensitic regimes showed similar sinusoidal elastic deformation at cycling frequencies 0.1 Hz and 18.3 kHz, and strains were comparable over the entire gauge section of the specimen. XRD data showed progressive growth of austenitic bands in formerly martensitic areas with increasing numbers of ultrasonic cycles. This increased specimen stiffness and cyclic stresses promoting crack initiation, which nearly exclusively occurred at cracked surface inclusions. The strain versus fatigue lifetime diagram shows a pronounced change in slope below 106 cycles. The overlapping properties measured at low and ultrasonic frequency demonstrate that ultrasonic fatigue testing is in principle appropriate for rapid characterization of the cyclic properties of Nitinol.

Radiographically Apparent Acetabular Sourcil Landmarks Are Created by Comparable Regions of the Pelvis With Extraarticular Bone Variably Confounding Estimates of Joint Coverage.

The severity of hip dysplasia is characterized by radiographic measurements that require user definition of the acetabular sourcil edge, a bony landmark for which the corresponding three-dimensional (3D) anatomy is not well defined in any imaging plane. To use digitally reconstructed radiographs to determine: (1) What 3D anatomy is contributing to the "acetabular sourcil" location used to make lateral center-edge angle (LCEA) and anterior center-edge angle (ACEA) measurements in standing AP and false-profile radiographic views, respectively? (2) How do intraobserver and interobserver agreement in LCEA and ACEA translate into agreement of the 3D anatomy being evaluated? (3) How distinct are regions around the acetabular rim circumference that are evaluated by LCEA and ACEA measurements on radiographs? Between January 2018 and May 2019, 72 patients were indicated for periacetabular osteotomy to treat hip dysplasia or acetabular retroversion at our institution. From these patients, a series of 10 patients were identified of the first 12 patients in 2018 who were treated with periacetabular osteotomy, excluding two with missing or low-quality clinical imaging. A second series of 10 patients was identified of the first 11 patients in 2019 who were treated with periacetabular osteotomy and concurrent hip arthroscopy, excluding one who was missing clinical imaging. Pelvis and femoral bone surface models were generated from CT scans of these two series of 10 patients. There were 15 female and five male patients, with a median patient age of 18 years (IQR 17 to 23 years), a preoperative LCEA of 22° (IQR 18° to 24°), and a preoperative ACEA of 23° (IQR 18° to 27°). Exclusion criteria included missing preoperative CT or standard clinical radiographic imaging or severe joint incongruity. To address our first study question, digitally reconstructed radiographs matching each patient's standing AP and false-profile clinical radiographs were created from the segmented CT volumes. A board-certified orthopaedic surgeon and three trained researchers measured LCEA and ACEA on the digitally reconstructed radiographs, and the selected sourcil points were projected back into coordinates in the 3D anatomic space. To address our second study question, intraobserver and interobserver agreement in radiographic coverage angles were related to variations in 3D coordinates of the selected bony anatomy. Lastly, to address our third study question, 3D locations around the acetabular rim identified as contributing to the lateral and anterior sourcil points were summarized across patients in a clockface coordinate system, and statistical analysis of the "time" separating the 3D acetabular contributions of the sourcil edges was performed. The 3D anatomy contributing to the lateral sourcil was a variable length (27 mm [IQR 15 to 34 mm]) span of the laterosuperior acetabular edges, with contributions by the anterior inferior iliac spine in 35% (7 of 20) of hips. The anterior sourcil reflected a 28-mm (IQR 25 to 31 mm) span of bone from the medial ilium (posterior-medial to the anterior-inferior iliac spine and anterior-lateral to the arcuate line) to the anterior and lateral edges of the acetabulum. Interobserver variability was good for LCEA (intraclass correlation coefficient [ICC] 0.82 to 0.83) and moderate to good for ACEA (ICC 0.73 to 0.79), whereas the agreement in identified 3D sourcil locations varied widely (ICC 0.32 to 0.95). The acetabular edge of the 3D anatomy contributing to the anterior sourcil overlapped the circumferential range of the acetabular rim contributing to the lateral sourcil. Projection of two-dimensional radiographic landmarks contributing to the diagnosis of structural hip deformity into 3D allowed for the identification of the overlapping bony anatomy contributing to radiographically visible anterior and lateral sourcil edges. This work leveraging digitally reconstructed radiographs and 3D pelvis anatomy has found that bone outside the joint contributes to the radiographic appearance of the sourcil and may variably confound estimates of joint coverage. Furthermore, the substantial overlap between the acetabular bone contributing to measurement of the LCEA and ACEA would indicate that these angles measure similar acetabular deformity, and that additional measures are needed to assess anterior coverage independent of lateral coverage.

Protective potential of high-contrast mineral-bonded layers on reinforced concrete slabs subjected to uniform shock waves

This study compares the blast performance of reinforced concrete (RC) slabs with and without strengthening on the impact-facing side. The strengthening strategy employed the application of two thin layers of materials with a high mutual stiffness offset, i.e., high-contrast layers. The first is a low-strength, low-modulus damping layer made of infra-lightweight concrete, followed by a second layer of high-ductility fiber-reinforced concrete. The plain RC slabs under investigation vary in thickness of either 40mm or 100mm. The layered specimens consist of a 40mm thick RC slab strengthened with a 40mm damping layer and a 20mm cover SHLC3 layer. This configuration enables a comparison of its behavior with the unstrengthened specimen (a plain 40mm thick RC slab) and a specimen with a similar eigenfrequency (the plain 100mm thick RC slab). The employed shock tube subjects the specimens to two rapidly rising areal pressures: a low-pressure wave reaching approximately 0.4MPa and a high-pressure wave peaking at around 1.2MPa. The study assesses the specimens’ response in terms of accelerations, velocities, and deformations. Additionally, it evaluates damage by analyzing crack patterns, Ultrasonic Pulse Velocity (UPV) measurements, and damping analysis. Overall, the layered specimens exhibited performance nearly equivalent to the 100mm thick specimens, displaying similar deformations and velocities despite having lower mass and bending stiffness. The high-pressure shock wave hardly damaged the layered specimens, unlike the 40mm thick slabs.

Comparative First-Principles Study of the Y2Ti2O7/Matrix Interface in ODS Alloys

Oxide-dispersion-strengthened (ODS) alloys generally exhibit extraordinary service performance under severe conditions through the formation of ultrafine nano oxides. Y2Ti2O7 has been characterized as the major strengthening oxide in Fe-based ODS alloys. First-principles energetic analyses were performed to investigate the structural, elastic and interface properties of Y2Ti2O7 in either Fe-based or Ni-based ODS alloys. Y2Ti2O7 has comparable elastic constants to bcc-Fe and fcc-Ni and similar elastic deformation compatibility in Y2Ti2O7-strengthened Fe-based and Ni-based ODS alloys is therefore expected. The Ni/oxide interface has generally better thermostability than Fe/oxide across the whole range of the concerned oxygen chemical potential. Further interface bonding and adhesion calculations revealed that Y2Ti2O7 can enhance the bonding strength of Ni/Y2Ti2O7 through d-d orbital interaction between the interfacial YTi layer and Ni layer, while the interface bonding between the Fe layer and YTi layer is weakened compared to the metal matrix. First-principles calculations suggest that Y2Ti2O7 can be a candidate for strengthening nano-oxides in either Fe-based or Ni-based ODS alloys with well-behaved mechanical properties for fourth-generation fission reactors and further experimental validations are encouraged.

Comparative study on the thermal and tribological properties of PA12 and PA11 for coating applications

AbstractIn this study, the performance and potential applicability of polyamide‐12 (PA12) as an alternative to polyamide‐11 (PA11), which is currently used in the coating processes of sliding tools present in cardan shafts, was investigated. The advantages of PA12 powder instead of PA11 in cardan shafts' coating include ease of supply and cost‐effectiveness, while still achieving similar performance. Therefore, PA12 is a more economical choice for coating applications. The PA11 and PA12 neat polymers were characterized via differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Based on the analyses, PA12 demonstrated substantial advantages over PA11. It showed a 16°C improvement in decomposition temperature and a 50% increase in crystallinity, enhancing stability under operational conditions, whereas PA11 exhibited approximately 6–7% higher values in crystallization and melting temperatures. The wettability behavior of the steel substrates coated with those polyamides was measured via contact angle analysis. Wear properties and morphologies of coatings were examined using a ball‐on disc test and scanning electron microscopy, respectively and comparatively. Furthermore, PA12 typically displays 30% lower wear rates and similar deformation patterns in tests, thereby presenting itself as a cost‐effective and widely accessible option for coating applications in comparison to PA11.

Crystal plasticity modeling of prior austenite orientation effects on deformation behaviors of martensitic steels under different strain paths

The influence of prior austenite grain (PAG) orientation on the deformation behavior of a low-carbon martensitic steel is investigated using crystal plasticity (CP) modeling with hierarchical representative volume elements (RVEs). The Kurdjumov-Sachs (K-S) relationship is refined for accurate PAG reconstruction in martensitic steel. A robust calibration strategy for CP parameters based on nanoindentation tests is developed by integrating analytical calculations with inverse methods. Virtual polycrystalline aggregates are subsequently generated by manipulating initial PAG orientations. The simulations reveal that assigning cube texture to PAGs enhances strain hardening of martensite under plane strain tension. Moreover, the RVEs with brass and copper orientated PAGs exhibit similar deformation behavior, and a more homogeneous strain distribution is realized in the RVE with PAG cube orientation. The influence of PAG orientation on stress and strain fields is correlated with lattice rotation behavior during deformation. Notably, different strain paths elicit distinct lattice rotation trajectories, wherein uniaxial tension and plane strain tension favor grains reorientation toward hard γ-fiber, whilst equi-biaxial tension drives the crystal matrix to concentrate on 〈001〉 and 〈011〉 directions. These findings provide insights into the intricate relationship between microstructural orientation and deformation behavior in martensitic steels, which is crucial for performance optimization.

Insight into synergistic effect of zinc oxide/expanded vermiculite composite (ZnO/EVMT) on bituminous mixture performances under different aging conditions

Zinc oxide/expanded vermiculite composite (ZnO/EVMT) with synergistic effect can effectively retard bitumen aging behavior, but the effect on road and mechanical performance of bituminous mixture under different aging conditions is unclear, which hinders its application and promotion. Based on the above, this study is meant to reveal the synergistic effect of ZnO/EVMT on bituminous mixture, with the ultraviolet absorber (UVA) compounding with antioxidant (AO) (label as UVA+AO, the same component ratio as ZnO/EVMT) and hydrated lime (HL) modifier serving as comparison. Then, the influence of ZnO/EVMT on the laboratory performances, including road performance and mechanical properties, of bituminous mixtures under four different aging conditions (unaged, long-term oven aging, long-term continuous and long-term all-weather photo-oxidative aging conditions) were investigated. Results show that under unaged condition, the addition of ZnO/EVMT can enhance road performance of bituminous mixture, and has similar effect to that of HL modifier and more positive effect than that of UVA+AO modifier. Under long-term oven aging condition, bituminous mixture containing ZnO/EVMT and HL have similar deformation resistance. ZnO/EVMT and the other two modifiers can enhance the low-temperature property, water stability and fatigue property of bituminous mixture, and ZnO/EVMT modified bituminous mixture has the highest low-temperature property and the lowest property change sensitivity. Under two long-term photo-oxidative aging conditions, ZnO/EVMT modified bituminous mixture generally exhibits higher creep deformation and deformation growth rate but lower mechanical performance changing rate than base bituminous mixture. Therefore, ZnO/EVMT can improve bituminous mixture road performance and reduce its aging sensitivity under different aging conditions. And the expected service life and durability of bituminous pavement will benefit from its promotion practice.

Spatiotemporal dominance of afterslip and viscoelastic relaxation revealed by four decades of post-1973 Luhuo earthquake observations

Measuring surface displacements driven by afterslip and viscoelastic relaxation following large earthquakes enables inferring frictional and rheological properties of Earth's outermost layers where hazardous earthquakes occur. However, the two concurrent mechanisms generate similar and intertwined surface deformations, complicating the extraction of physical information from the measurements. Here, we quantify the spatiotemporal dominance of co-evolving afterslip and viscoelastic relaxation following the 1973 Ms 7.6 Luhuo earthquake in eastern Tibet, using 42 years (1976‒2018) of fault-crossing short-baseline observations. The finite-fault slip of this M7+ earthquake was constructed from triangulation data measured in 1961‒1975. Based on the model incorporating two postseismic relaxation mechanisms and calibrated by the measurements over four decades, we show that, in the temporal domain, afterslip may produce geodetically measurable deformations (>1.5 mm/yr) in local near-field regions even 20 years after the mainshock, with spatially broader impact within ∼10 years. Viscoelastic relaxation may last for nearly six decades, imposing a broad influence for three decades. In the spatial domain, afterslip may produce deformations within ∼2 times the seismogenic depth (SD; 20 km) from the fault, but dominantly in the near-field of ∼1 times the SD. In contrast, viscoelastic relaxation may affect a much wider region reaching 200 km. While afterslip and viscoelastic relaxation collectively affected the region ∼2 times the SD from the fault in the early postseismic period, their resulting deformations gradually separated in space with time, with afterslip-induced deformation shrinking toward the fault, and surface deformation caused by viscoelastic relaxation concentrating in the mid-field, ∼2–3 times the SD from the fault. Their spatiotemporal partitioning helps better learn fault frictional properties and lithospheric rheology based on geodetic data acquired from different domains.

Cyclic tensile response and crack closure performance of novel superelastic Ni-Ti SMA cable grid-reinforced engineered cementitious composites

To further improve the tensile and self-healing properties of engineered cementitious composites (ECCs) for their special uses such as harsh environments, plastic hinge regions, and old members strengthening, an innovative high-performance superelastic Ni-Ti shape memory alloy (SMA) cable grid-reinforced ECC (SMACG-ECC) was first proposed and tested in this study. The effects of water-binder ratio, cable grid material, and reinforcement ratio on the cyclic tensile properties and crack closure performance of the proposed SMACG-ECC were systematically examined. Test results revealed that the tensile strength, initial crack strength, ultimate tensile strain, dense crack, crack closure, and self-healing properties of the traditional ECC were obviously improved by being reinforced with the SMACG. Compared with the ordinary steel cable grid-reinforced ECC (SCG-ECC), the proposed SMACG-ECC exhibited approximately 50 % lower first crack strength, similar tensile strength and deformation ductility, but a 53.7 %-75.1 % greater energy dissipation, 75.8 %-80.2 % lower residual strain, and 80.4 %-83.4 % smaller maximum residual crack width. The tensile properties, cracking performance, and self-healing ability improved with the incorporation of SMACG as well as the increase in reinforcement ratio. Notably, most specimens showed satisfactory composite operation with no cable ends slipping during the entire cyclic loading process, with a maximum tensile strain amplitude of 8 %.

Neck muscle function improves after neck exercises in individuals with whiplash-associated disorders: a case–control ultrasound study with speckle-tracking analyses

A whiplash injury can alter neck muscle function, which remains years after the injury and may explain why symptoms such as persistent pain and disability occur. There is currently limited knowledge about dynamic neck muscle function in chronic whiplash-associated disorders (WAD), and about the extent to which altered muscle function can improve after rehabilitation. Ultrasound can detect mechanical neck muscle function by measuring real-time deformation and deformation rate in the muscles. This method was used for five dorsal neck muscles in participants with chronic WAD versus matched controls in resistant neck rotation. We obtained real-time, non-invasive ultrasound measurements using speckle tracking, multivariate analyses, and mixed-design ANOVA analyses. The results showed altered deformation in the three deepest neck muscle layers, with less deformation area in the WAD group compared to controls in rotation to the most painful side at baseline. Participants in the WAD group performed three months of neck-specific exercises, resulting in improved deformation in the deep neck muscles in WAD and with a similar deformation pattern to controls, and the significant group differences ceased. We reveal new and important insights into the capability of ultrasound to diagnose altered neck muscle function and evaluate an exercise intervention.

High incidence of femoroacetabular impingement deformity in bi-column acetabular fractures.

Dynamic interaction of cam and pincer deformities can result in pathological contact forces in femoroacetabular impingement (FAI) syndrome. Similar deformities were noted during acetabular fracture reconstruction. We hypothesise that the prevalence of FAI deformity is higher in patients sustaining acetabular fractures than in a control group. This retrospective radiographic study compared the parameters that define FAI deformity in 100 patients consecutively admitted to a trauma unit with an acetabular fracture and a control group of 100 patients with lateral compression pelvic fracture without acetabular injury. Both underwent identical clinical imaging. Centre-edge angles (CEA) and alpha angles were used to define patients with pincer, cam, or mixed FAI deformity. There were significantly more patients with FAI deformity in the acetabular fracture group than in the control group (71% vs. 18%, p < 0.0001). There were considerably more fractures involving both anterior and posterior acetabular columns in patients with 'pincer' sockets (p = 0.02, OR = 2.95, 95% CI, 1.12-7.78). There is a high prevalence of cam and pincer deformities in patients with acetabular fractures, particularly bi-column fractures.

Strain-independent auxetic metamaterials inspired from atomic lattice

Metamaterials with strain-independent negative Poisson's ratio (NPR) and Young's modulus are essential for the applications with extreme loading conditions. However, strain-independent auxetic metamaterials are rare, and there is a lack of design inspiration for them. In this paper, we present a novel auxetic metamaterial inspired from the atomic lattice with strain-independent NPR. The novel NPR properties due to the unique atomic lattice keep valid when scaling up by 6 orders of magnitude to macroscopic metamaterials, with the similar deformation mechanism. The NPR and Young's modulus keep constant with increasing loading strain. These strain-independent auxetic effects are robust with various designable geometric parameters in wide ranges. Furthermore, the geometric parameters optimization for the auxetic metamaterial is conducted through developing the matrix displacement method. An optimized metamaterial is achieved with 3 times enhancement of auxeticity and 2 orders of magnitude enhancement of Young's modulus, compared to the initio architectures. This work provides a wealth of inspirations from atomic lattice in nature to design strain-independent macroscale auxetic metamaterials.

Micromechanism insights and constitutive modeling for deformation in a novel high manganese austenitic steel

We explore the mechanical behavior and microstructural evolution of a novel high manganese austenitic steel (HMAS), extensively applied in underground engineering and structural construction. Our investigation focuses on two variants of HMAS, namely HMAS-1.9 and HMAS-10, which exhibit distinct yield strengths and elongation behaviors. Electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to elucidate the evolution of microstructures during plastic deformation. Based on these experimental results, we developed a new phenomenological multiscale constitutive model that captures the mechanical behavior of HMAS, integrating micromechanisms and microstructural evolutions. Optimized with the MATLAB genetic algorithm toolbox, this model was successfully implemented in a uniaxial tensile finite element model (FEM) within ABAQUS, proving its efficacy in predicting both macroscopic flow stress and microstructural evolutions. Our findings highlight the important roles of initial grain size, dislocation density, and twin fraction in determining the mechanical properties of HMAS. Throughout the deformation process, both HMAS variants demonstrate similar plastic deformation behaviors, characterized by comparable rates of increase in dislocation density and twinning fraction, accompanied by a consistent trend of grain refinement. These findings not only deepen our understanding of the complex relationship between microstructure and mechanical properties of the HMAS steel, but also provide an effective multiscale constitutive modeling approach for predicting its deformation behavior.

A Robust AR-DSNet Tracking Registration Method in Complex Scenarios

A robust AR-DSNet (Augmented Reality method based on DSST and SiamFC networks) tracking registration method in complex scenarios is proposed to improve the ability of AR (Augmented Reality) tracking registration to distinguish target foreground and semantic interference background, and to address the issue of registration failure caused by similar target drift when obtaining scale information based on predicted target positions. Firstly, the pre-trained network in SiamFC (Siamese Fully-Convolutional) is utilized to obtain the response map of a larger search area and set a threshold to filter out the initial possible positions of the target; Then, combining the advantage of the DSST (Discriminative Scale Space Tracking) filter tracker to update the template online, a new scale filter is trained after collecting multi-scale images at the initial possible position of target to reason the target scale change. And linear interpolation is used to update the correlation coefficient to determine the final position of target tracking based on the difference between two frames. Finally, ORB (Oriented FAST and Rotated BRIEF) feature detection and matching are performed on the accurate target position image, and the registration matrix is calculated through matching relationships to overlay the virtual model onto the real scene, achieving enhancement of the real world. Simulation experiments show that in complex scenarios such as similar interference, target occlusion, and local deformation, the proposed AR-DSNet method can complete the registration of the target in AR 3D tracking, ensuring real-time performance while improving the robustness of the AR tracking registration algorithm.

Surface deformation monitoring and forecasting of sinabung volcano using interferometry synthetic aperture radar and forest-based algorithm

The Sinabung volcano on Sumatra Island stands out as one of the most active volcanos, having recorded the highest number of eruptions since it resumed activity in 2010. The eruptive activities have caused significant deformations on the volcano's surface. This research aimed to analyze, cluster, and forecast its deformation patterns based on Sentinel-1 A time series data from 2016 to 2023. The differential interferometry synthetic aperture radar (DInSAR) technique was used to monitor monthly deformations and to create time series data. A forest-based forecast (FBF) model was used to predict the rate of changes in volcano surface inflation from January 2024 to December 2027. The deformation times series patterns were also analyzed and clustered into three regions to reveal areas with similar deformation behaviors. The results indicated that Mount Sinabung's deformation is an overall continuous sporadic phenomenon where random ground inflation and deflation were recorded throughout the area with an average deformation rate ranging from 0.06 to 0.32 cm/month and an overall average of 0.197 cm/month with a standard deviation of 0.96 cm, confirming that the volcano is inflating. The highest single-pixel monthly inflation of 4.62 cm was recorded in 2023, while the highest deflation occurred in 2018 at −4.58 cm. The FBF model predicted a gradual and increasing inflationary pattern at the rate of 0.54 cm/month for 2024–2027, higher than the average of the observed data. The deformation within the lava dome and caldera poses a significant risk and could lead to wall collapses and landslides in the crater dome, potentially triggering explosive eruptions. The outcomes of this research serve as valuable supporting information and offer an early warning of potential volcanic disasters in the future.

Experimental investigation on enhanced combustion of methanol/heavy fuel oil by droplet puffing at elevated temperatures

To achieve high-efficiency combustion of heavy fuel oil (HFO), this study investigated the combustion characteristics of methanol/HFO droplets with methanol content from 10 to 30% using the suspension method under ambient temperature from 923 to 1023 K. The combustion of methanol/HFO droplets was summarized as a two-phase process consisting of six typical stages, emphasizing liquid phase. Especially, the fluctuation evaporation stage, induced by frequent and intense puffing, was identified as prominent character. Both the ignition delay and lifetime of HFO and methanol/HFO droplets decreased with increasing ambient temperatures. For the methanol/HFO droplet, the ignition delay and droplet lifetime increased with the increasing methanol content. Prominently, compared to HFO, HM10 had the most significant reduction in droplet lifetime and TINL under the same operating conditions, which indicated that the addition of 10% methanol accelerated the combustion process and reduced soot generation. Additionally, the thermos-dynamic characteristics of methanol/HFO droplets were investigated. Puffing was primarily attributed to superheating of methanol and pyrolysis of heavy components in HFO, which resulted in active and passive rupture of bubbles. Similarity and maximum deformation were employed to qualitatively distinguish between them. The obtained findings aimed to develop a promising alternative fuel to reduce emissions and preserve energy.

Distant education period during the COVID pandemic: a hindsight study

A combined approach to analyze distant education period during the COVID-pandemic is presented in the article: it is viewed from the point of view of sociology, pedagogics and psychology. Comparative analysis revealed that compulsory distant education period of the educational process participant concerned is comparable to a drinking-bout of the substance-addicted individual. Consequently, this period is called distant-education-bout in the article. According to observations and experimental results, technologically addicted and substance-addicted individuals over the period experience similar deformation of social, emotive, physiological and cognitive aspects. Over the long distant education period teachers, students and schoolchildren experienced sufferings in social sphere, developed the feeling of loneliness and anhedonia; their empathy and cognitive abilities declined and physique deteriorated. Going back to classroom studies is characterized by «recovery stress», this process appearing as complicated and lengthy as entering total distant education mode, with its consequences still haunting many of us. The problems of genetic predisposition to developing Internet addiction, legal and political regulation of digital learning environment are dealt with in the final parts of the article, providing ground for further research.

Revisiting the deformation and migmatization of the Tongbai complex in the Tongbai orogenic belt, central China

The Tongbai complex plays an important role in the understanding of the tectonic evolution of the Tongbai‐Dabie orogenic belt. By detailed structural analysis, new zircon U–Pb dating, zircon Lu–Hf analysis and whole‐rock elements for the rocks in the Tongbai complex and the wrapped shear zones, we suggested that the Tongbai complex was derived from the partial melting of the basement of Yangtze Block and experienced a uniform orogen‐parallel extension with a top‐to‐NW shearing at 142–133 Ma. The migmatites yield a migmatization age of 116 ± 2 Ma and are identical to the metamorphic age of 115–111 Ma from the L and LS tectonites in the Tongbai complex. The late Early Cretaceous migmatization may give rise to the severance of the uniform top‐to‐NW shear zone and lead to an antiform folding of the Tongbai complex. The similar deformation and migmatization of the complexes in both the Tongbai and Dabie orogenic belts suggest that the Tongbai‐Dabie orogenic belt is likely to have a similar tectonic transformation from orogen‐parallel to orogen‐perpendicular extension in the Early Cretaceous, namely a uniform orogen‐parallel extension of the ductile lithosphere during the early Early Cretaceous and a widespread migmatization during the late Early Cretaceous.