Search Results (1,438)

High-resolution single-channel Sparker (1 kJ) profiles have been carried out to reconstruct the seismo-stratigraphic architecture of a sector of the Campania–Latium Tyrrhenian margin (Southern Tyrrhenian Sea, Italy). Seven seismic lines between the Volturno river mouth and the southern Latium margin were processed in IHS Kingdom^® software (4.0) at the University of Sannio (Benevento, Italy) and interpreted at the CNR-ISMAR (Naples, Italy) using seismic- and sequence-stratigraphic criteria. The Sparker dataset refines correlations with previously interpreted Chirp profiles and improves the imaging of fault patterns and key stratigraphic markers. Several seismo-stratigraphic units displaced by normal faults were recognized. Unit 1 represents the acoustic substratum of the high-resolution record, whereas Unit 2 corresponds to a thick relict prograding wedge that thickens toward the Volturno river mouth. A mounded lowstand unit is interpreted as deposits related to the Volturno river delta/fan system. Volcanic units, including the Villa Literno volcanic complex and local volcanic edifices, are locally identified. Overall, the results show that Sparker processing and interpretation provide robust constraints on the stratigraphic architecture and Late Quaternary tectono-sedimentary evolution of deltaic continental shelves. In particular, while previous Chirp studies have effectively constrained the stratigraphic architecture of the Late Quaternary depositional sequence and the geometry of the NYT reflector, this study provides new insights about deeper progradational seismo-stratigraphic units and related volcanic deposits and their tectono-stratigraphic setting. Full article

To address the difficulty of controlling surrounding rock subjected to repeated repair-induced disturbances, the characteristics of the roadway surrounding rock and its deformation–failure mechanisms were examined. An experimental scheme for surrounding-rock control was formulated, and a three-dimensional numerical model was established. Four support schemes were evaluated to identify a rational support method and corresponding parameters: (a) rock bolts and cable bolts; (b) rock bolts, cable bolts, and floor cable bolts; (c) rock bolts, cable bolts, floor cable bolts, and U-shaped closed steel sets; and (d) rock bolts, cable bolts, floor cable bolts, U-shaped closed steel sets, and grouting. Comparative analyses were conducted in terms of plastic-zone evolution, stress-field distribution, surrounding-rock displacement, and the mechanical response of the support structures. The results indicate that, in roadways experiencing multiple repair disturbances and supported only by rock bolts and cable bolts, distinct stress-concentration zones develop within the supported surrounding rock, suggesting that reliance solely on bolts and cables is unfavorable for effective rock-mass control. Grouting improves the overall integrity and self-bearing capacity of the surrounding rock. Both the U-shaped closed support and the combined U-shaped closed support with grouting effectively restrain surrounding-rock deformation, and the corresponding stress distribution shows no pronounced stress-concentration zones. Based on the analyses of surrounding-rock displacement, support-structure loading, and incremental shear strain, the effectiveness of the support schemes in mitigating roof and floor displacement ranks, in descending order, as (d), (c), (b), and (a). Engineering practice further demonstrates that the combined support system consisting of 29U-type sets, grouted bolts, and bundle-type grouted cable bolts provides effective control over the deformation and failure of the roadway surrounding rock. Full article

The utilization of thermoelectric systems within internal combustion engines has emerged as a promising approach to recuperate a portion of the energy dissipated through exhaust gases. The objective of this study is twofold: firstly, to assess the heat recovery potential of a thermoelectric generator integrated into a diesel engine, and secondly, to elucidate the impact of varying operating conditions on the efficiency of heat recovery. For this purpose, the thermoelectric generator was mounted onto the exhaust pipe of a single-cylinder diesel engine featuring a common-rail fuel injection system with pilot injection and a displacement volume of 1.12 L. The calculations were conducted under 100% engine load at 1500 RPM engine speed and three different injection timing settings (−2, STD, and +2 °CA). The optimum heat recovery efficiency was determined to be 5.02%, which was achieved under the following conditions: B50 fuel, −2 °CA injection timing, 1500 RPM engine speed, and 100% engine load. Full article

Low gas recovery in the Sebei-2 gas field is linked to residual gas trapping under water encroachment. This study investigates the pore-scale trapping behaviour of residual gas in three types of layer: conventional, low-resistivity, and low-acoustic high-resistivity. High-fidelity pore structures were reconstructed by integrating mercury intrusion porosimetry with thin-section data and microfluidic models were designed using the Quartet Structure Generation Set method and fabricated by wet etching. Visualized displacement experiments were performed under different wettability conditions and water invasion rates, and image analysis was used to quantify the distribution of trapped gas. Results show that the low-resistivity gas layer exhibits the highest residual gas saturation (30.57%), followed by the low-acoustic high-resistivity gas layer (20.20%), while the conventional gas layer has the lowest (15.29%). These values correspond to apparent pore-scale gas recoveries of about 48.95%, 65.01%, and 72.14% for the low-resistivity, low-acoustic high-resistivity and conventional gas layers, respectively. In hydrophilic systems, wetting-film thickening and flow diversion are the main trapping processes, whereas in hydrophobic systems, flow diversion dominates and residual gas decreases markedly. Increasing the water invasion rate reduces trapped gas in the conventional and low-resistivity layers, whereas in the strongly heterogeneous low-acoustic high-resistivity layer, higher invasion intensity strengthens preferential channelling/viscous fingering, leading to a non-monotonic residual gas response. These findings clarify the differentiated pore-scale trapping mechanisms of gas under water encroachment and highlight that mitigating water film-controlled trapping in low-resistivity layers and flow diversion trapping in low-acoustic high-resistivity layers is essential for mobilizing trapped gas, improving dynamic reserves, and ultimately enhancing the economic recovery of water-bearing gas reservoirs similar to the Sebei-2 gas field. Full article

Background: Neuromodulation encompasses a range of methods aimed at selectively modifying nervous system function to enhance motor and neurophysiological processes. Although neuromodulation suits have shown benefits in clinical populations, their application in sports remains unexplored. Therefore, the aim of this case study was to examine the acute effects of a neuromodulation suit on the contractile properties of the rectus femoris muscle in an elite football player. Methods: The subject was an 18.8-year-old male professional football player. After conducting an anthropometric evaluation, initial tensiomyography (TMG) was carried out to evaluate the contractile properties of the rectus femoris, such as delay time (Td), contraction time (Tc), sustain time (Ts), relaxation time (Tr), and maximum radial displacement (Dm), in both legs. The athlete then donned a neuromodulation suit set to 20 Hz for a duration of 60 min. Following this, the same TMG measurements were repeated to assess post-intervention changes. Results: The right leg showed a reduction in Tc from 33.33 to 31.93 milliseconds (ms); Dm increased from 6.61 to 11.17 millimeters (mm). Conversely, the left rectus femoris exhibited prolonged Tc from 26.84 to 29.45 ms. Conclusions: A single 60 min session of neuromodulation suit application produced acute changes in muscle contractile properties. Findings suggest a potential positive effect on rapid force production and reduced muscle stiffness, alongside notable inter-limb variability. Full article

This study systematically verified the applicability and accuracy of the Probability Density Evolution Method (PDEM) in the probabilistic modeling of the dynamic response of anchored rock slopes under random seismic action through large-scale shaking table model tests. Across 144 sets of non-stationary random ground motions and 7 sets of white noise excitations, key response data such as acceleration, displacement, and changes in anchor axial force were collected. The PDEM was used to model the instantaneous probability density function (PDF) and cumulative distribution function (CDF), which were then compared with the results of normal distribution, Gumbel distribution, and direct sample statistics from multiple dimensions. The results show that the PDEM does not require a preset distribution form and can accurately reproduce the non-Gaussian, multi-modal, and time evolution characteristics of the response; in the reliability assessment of peak responses, its prediction deviation is much smaller than that of traditional parametric models; the three-dimensional probability density evolution cloud map further reveals the law governing the entire process of the response PDF from “narrow and high” in the early stage of the earthquake, “wide and flat” in the main shock stage, to “re-convergence” after the earthquake. The study confirms that the PDEM has significant advantages and engineering application value in the analysis of random seismic responses and the dynamic reliability assessment of anchored slopes. Full article

Robotic total stations are multi-sensor integrated instruments widely used in displacement monitoring. The principles of polar coordinate or forward intersection systems are usually utilized for calculating monitoring results. However, the polar coordinate method lacks redundant observations, leading to unreliable results sometimes. Forward intersection requires two instruments for automated monitoring, doubling the cost. In this regard, this paper proposes a novel automated displacement monitoring method using the robotic total station assisted by a fixed-length track. By setting up two station points at both ends of a fixed-length track, the robotic total station is driven to move back and forth on the track and obtain observations at both station points. Then, automated monitoring based on the principle of forward intersection with a single robotic total station is achieved. Simulation and feasibility tests show that the overall accuracy of forward intersection is better than that of polar coordinate system as the monitoring distance increases. At the same time, regardless of tracking a prism or not, the robotic total station is able to automatically find and aim at the targets when moving between station points on the track. Further practical tests show that the reliability of the monitoring results of the proposed method is superior to the polar coordinate method, which provides new ideas for ensuring the reliability of results while reducing cost in actual monitoring tasks. Full article

Bioelectrical impedance analysis (BIA) is a widely used and an easy-to-apply method for determining body composition. However, its accuracy depends on population-specific equations. The aim of the present study is to identify the most appropriate fat-free mass (FFM) prediction equation for an Eastern European population using air-displacement plethysmography (ADP) as the reference method. The study group included 101 Caucasian subjects (56 women and 45 men) with an average body mass index (BMI) of 25.37 ± 5.45 kg/m². One set of FFM_BIA values was automatically calculated with the analyzer (Maltron BioScan 920-2), and four others were computed using the published equations of Kyle, Kanellakis, Heitman, and Deurenberg. The results were compared to FFM_ADP values measured using a BOD POD Gold Standard Body Composition Tracking System by Bland–Altman analysis. The smallest bias was obtained with the equation by Deurenberg, which underestimated FFM by only −0.22 ± 4.52 kg. The largest bias was obtained with the equation by Kyle (5.92 ± 4.73 kg), followed by the formula of Kanellakis (3.04 ± 4.65 kg). The equations by Heitman and the Maltron inbuilt formula overestimated FFM by 2.15 ± 4.27 kg and, respectively, 1.95 ± 4.3 kg. Although Maltron’s automatically generated values were very strongly correlated with ADP results (CCC = 0.93, SEE = 4.7), the formula by Deurenberg provided the most reliable estimates in the studied population. Full article

Design: Retrospective observational cohort study conducted at university and private practice setting. Objective: To evaluate whether operator experience affects the predictability of orthodontic tooth movements and the overall treatment duration in clear aligner therapy. Materials and Methods: This retrospective observational study was conducted at the Dental School of the University of Turin and in private orthodontic settings. Seventy-two patients (50 females, 22 males; median age: 24.6 years; IQR = 5.9) with mild to moderate malocclusions were included and equally distributed between two groups: 36 patients treated by postgraduate orthodontic students (Group B) and 36 patients treated by experienced orthodontists (Group E). Post-treatment digital models were analyzed to assess discrepancies between the predicted and achieved tooth positions. The accuracy of specific movements—rotation, vertical displacement, and treatment duration—was statistically evaluated using the Mann–Whitney U test. Most of these differences, although statistically significant, remained below established thresholds for clinical relevance (0.5 mm/2°). Results: Expert operators achieved significantly greater accuracy in controlling the vertical movements of the upper central incisors (p = 0.01) and the rotational movements of the upper first molars (p = 0.03), upper lateral incisors (p = 0.03), lower incisors (p = 0.001), and lower premolars (p = 0.001). In contrast, non-expert operators demonstrated superior outcomes in the control of vertical movements of the upper premolars (p = 0.01) and in the rotational movement of the lower canines (p = 0.03). Treatment duration was significantly shorter in the expert group, with a median difference of 4.1 months (p = 0.0037). Conclusions: These findings confirm the importance of clinical experience in enhancing the predictability and efficiency of clear aligner therapy, particularly in complex movements. However, the improved performance of non-expert operators in selected areas—such as vertical control of upper premolars and rotation of lower canines—suggests that conservative movement planning may also play a role in improving clinical outcomes. Overall, expert clinicians achieved more predictable tooth movements and shorter treatment durations, underscoring the value of structured training and accumulated clinical expertise in optimizing clear aligner therapy. Full article

Indoor bouldering is a popular and rapidly growing sport in which climbers fall repeatedly from walls up to 4–5 m high, making lower-limb injuries common. It is therefore essential to understand fall kinematics and impact conditions, yet fall kinematics remain poorly documented because laboratory motion capture is impractical in gyms. This study aimed to validate a markerless multi-camera pipeline (Pose2Sim) against a 2D video annotation tool (Kinovea) for displacement and velocity measurement, and against IMUs for peak acceleration. Ten teenage athletes (3 males, 7 females; 14–17 years) performed 40 falls recorded with five cameras (GoPro HERO12, USA, 2.7 K, 240 fps) and three IMUs (Blue Trident, Vicon, UK; ±200 g, 1600 Hz). Cut-off frequencies were set using Yu’s method (13 Hz for video, 39 Hz for IMUs). Pose2Sim’s results closely matched those of Kinovea for fall height and peak velocity with non-significant differences but underestimated peak acceleration. At the forehead, no significant difference was found, likely due to smaller accelerations at the head. Markerless video analysis is appropriate for studying fall kinematics and typology in indoor bouldering. IMUs remain necessary to quantify impact intensity, and future work should explore the combination of both IMUs and video to overcome this limitation. Full article

Background: Obesity, defined as an abnormal accumulation of body fat, is becoming a global epidemic. Individuals with obesity may present with increased abdominal fat, which is associated with hypertension, altered respiratory mechanics, higher resting heart rate, and may contribute to an increased cardiovascular risk. Physiological parameters, such as heart rate, blood pressure, respiratory rate, and oxygen saturation, can change hours before the occurrence of a clinically relevant adverse event. Thus, physiological parameters can be considered good predictors of clinical deterioration. Obesity is also associated with physical dysfunctions that can impair physical performance. The non-pharmacological therapeutic strategy for the treatment of obesity involves lifestyle modifications, including a healthy diet and regular physical exercise. Whole-body vibration (WBV) exercise, a type of physical activity, has demonstrated benefits in several specific populations, including obese individuals. Objectives: The objective of this study was to evaluate the immediate effects of a single whole-body vibration (WBV) exercise session, consisting of 15 sets, using a vibration platform (VP) with alternating vertical or lateral displacement, on physiological parameters, perceived exertion, strength, and functionality in obese adults. Methods: Seventy-two obese adult participants were randomly divided into three groups (vertical group, alternating lateral group, and placebo group). Physiological parameters were assessed before, during, and after the intervention, in addition to perceived exertion, functionality, and muscle strength. Results: When comparing the results before and after the intervention, the heart rate–pressure product increased significantly in the alternating lateral group (p = 0.005), and heart rate increased significantly (p = 0.0001) and then decreased significantly (p = 0.030) only in the alternating lateral group. Post hoc analysis revealed a significant increase in perceived exertion in the lateral alternation group, from the period before the intervention to the 10th set (p = 0.006) and from the period before to the period after the intervention (p = 0.011). In the vertical group, a significant increase was observed from the period before the intervention to the 10th set (p = 0.020). Conclusions: In conclusion, considering all the findings of this study, whole-body vibration (WBV) exercise promoted some immediate changes in physiological parameters and perception of effort in obese adults. WBV exercise with the alternating vibration platform induced significant fluctuations in heart rate and increased the heart rate–blood pressure product, although with values within the normal range. Perception of effort increased in all groups. Considering the absence of discrepant changes in physiological parameters, impact on the cardiovascular system, and fatigue, the WBV exercise intervention in side-alternating or vertical vibration vibratory platforms can be considered a viable non-conventional exercise option for the obese population. Full article

This study aims to investigate the tip resistance mechanism of open-ended steel pipe piles under partially plugged conditions by decomposing the load-sharing contribution of the ring zone and the internal soil core. A virtual static loading test was performed using the two-dimensional discrete element method (2D-DEM). Note that the findings of this study were obtained within the range of the 2D-DEM analysis conditions and do not intend to directly reproduce the three-dimensional arching mechanism or to establish equivalence between 2D and 3D responses. Quasi-static conditions were ensured by identifying loading parameters such that the energy residual remained ≤5% during driving, rest, and static loading phases, and the sensitivity criterion |Δq_b|/q_b ≤ 3% was satisfied when the loading rate was halved or doubled. The primary evaluation range of static loading was set to s/D = 0.1 (10% D), corresponding to the displacement criterion for confirming the tip resistance in the Japanese design specifications for highway bridges. For reference, the post-peak mechanism was additionally tracked up to s/D = 0.2 (20% D). Within a fixed evaluation window located immediately beneath the pile tip, high-contact-force (HCF) points were binarized using the threshold τ = μ + σ, and their occupancy ratio φ and normalized force intensity I* were calculated separately for the ring and core regions. A density-based contribution index (“K_{-density share}”) was defined by combining “strength × area” and normalizing by the geometric width. The results suggest that, for the sand conditions and particle-scale ratios examined (D/d_50 = 25–100), the ring zone tends to carry on the order of 85–90% of the tip resistance within the observed cases up to the ultimate state. Even at high plugging ratios (CRs), the internal soil core gradually increases its occupancy and intensity with settlement; however, high-contact-force struts beneath the ring remain active, and it is suggested that the ring-dominant load-transfer mechanism is generally preserved. In the post-peak plastic regime, the K_{-density share} remains around 60%, indicating that the internal core plays a secondary, confining role rather than becoming dominant. These findings suggest that the conventional plug/unplug classification based on PLR can be supplemented by a combined use of plugging ratio CR (a kinematic indicator) and the ring contribution index (K_{-density share}), potentially enabling a continuous interpretation of plugged and unplugged behaviors and contributing to the establishment of a design backbone for tip resistance evaluation. Calibration of design coefficients, scale regression, and mapping to practical indices such as N-values will be addressed in part II of this study. (Note: “Contribution” in this study refers to the HCF-based density contribution index K_{-density share}, not the reaction–force ratio.) Full article

There exists an east–west trending albitite (breccia) zone, approximately 400 km in length, closely related to gold mineralization, in Devonian strata in the South Qinling tectonic belt. The genesis and formation age of these albitite (breccia) are of great significance for understanding gold enrichment mechanisms and guiding future exploration. Past studies have mainly focused on the Fengxian–Taibai area in the western segment of the albitite (breccia) zone, whereas the eastern segment remains significantly understudied. In this study, a systematic field investigation, as well as petrology, geochemistry, and accessory-mineral geochronology studies were conducted on albitites and albitite breccias in the Shangnan area, the eastern segment of the albitite (breccia) zone. The results show that the albitites are interlayered with or occur as lenses within Devonian clastic rocks. The albitite breccias are mostly enclosed in albitite and Devonian strata, and the clasts within are subangular, uniform in type, and exhibit minimal displacement. Both albitites and albitite breccias exhibit similar trace-element characteristics and detrital zircon age spectra to those of Devonian clastic rocks. Abundant hydrothermal monazites with U–Pb ages ranging from 260 to 252 Ma are present in both albitites and albitite breccias but absent in Devonian clastic rocks. Collectively, these results indicate that the albitites in the Shangnan area are of hydrothermal metasomatic origin, while the albitite breccias record hydraulic fracturing and cementation, and both are products of the same fluid activity event in the Late Permian. We propose that albitite (breccia) zones in the South Qinling tectonic belt were formed under distinct tectonic settings during different evolution stages of the Late Paleozoic Mianlüe Ocean. Specifically, the albitites (breccias) in the Shangnan area are products of thorough metasomatism, local fracturing, and cementation of Devonian clastic rocks by mixed fluids, which ascended along the Fengzhen–Shanyang Fault coeval with the emplacement of magmatic rocks related to subduction of the Mianlüe Ocean. In contrast, the albitite breccias in the Fengxian–Taibai area are the result of fluid activity during the transition from regional compression to extension after the closure of the Mianlüe Ocean. Full article

Although PINNs have demonstrated strong predictive capabilities in forward problems, their performance in inverse problems remains inadequate, largely due to unquantifiable noise encountered during the multi-parameter identification of prestressed concrete beams. Experimental measurements are often noisy, sparse, or asymmetric, while numerical or analytical models, although physically consistent, are typically approximate and lack regularization from well-defined multi-fidelity data. To address this limitation, this paper proposed a multi-fidelity data and prior-enhanced physics-informed neural network (MF-rPINN), which integrates multi-fidelity data with physics prior relational constraints to guide parameter identification using only sparse experimental observations. The MF-rPINN architecture is designed to enforce consistency between each training iteration and a prescribed set of experimental measurements, while embedding the second-order displacement function into the loss function. Experimental results demonstrate that the proposed MF-rPINN achieves accurate parameter identification even under noisy and incomplete observations, owing to the combined regularization effects of governing physical laws and the second-order displacement prior. The minimum relative errors of the elastic modulus are −6.49% and −9.32% under different and identical loading conditions, respectively, while the minimum relative errors of the prestress force are 0.65% and 4.51%. Compared with classical analytical approaches, MF-rPINN exhibits superior robustness and is capable of predicting continuous displacement fields of prestressed concrete beams while simultaneously identifying prestress force and elastic modulus. These advantages highlight the potential of MF-rPINN as a reliable surrogate modeling tool for practical engineering applications. Full article

This study investigates rainstorm-induced highway subgrade slope collapses in the coastal areas of Southeast China. By integrating the seepage–stress coupled finite element method with the strength reduction method, we simulate the entire process of seepage, deformation, and slope collapse under rainstorm conditions, analyzing the variation in the stability factor. The key findings are as follows: (1) During rainstorms, water infiltration increases soil saturation and pore water pressure, while reducing matrix suction and soil shear strength, leading to soil softening. (2) The toe of the subgrade slope first undergoes plastic deformation under rainstorms, which develops upward, and finally the plastic zone connects completely, causing collapse. The simulated landslide surface is consistent with the actual one, revealing the collapse mechanism of the subgrade slope. Additionally, the simulated displacement at the slope toe when the plastic zone connects provides valuable insights for setting warning thresholds in landslide monitoring. (3) The stability factor of the subgrade slope in the case study decreased from 1.24 before the rainstorm to 0.985 after the rainstorm, indicating a transition from a stable state to an unstable state. (4) Parameter analysis shows that heavy downpour or downpour will cause the case subgrade slope to enter an unstable state. The longer the rainfall duration, the lower the stability factor. Analysis of soil parameters indicates that strength parameters, internal friction angle, and effective cohesion exert a significant influence on slope stability, whereas deformation parameters, elastic modulus, and Poisson’s ratio have a negligible effect. Slope collapse can be timely forecasted by predicting the stability factor. Full article