Search Results (822)

Contacted liquid fluids, in most cases, have the tendency to directly merge into a single larger fluid to minimize the surface energy. We present an abnormal drop formation process of contacted Cu liquid films with a radius of 101.7 Å or larger on carbon substrates by using molecular dynamics simulations. The formation process consists of consecutive pinch-off and full coalescence stages connected by detachment. The dominant motions of the bridge, away from the center and downward to the substrate, lead to the pinch-off of the initially connected droplets. The motions of the droplets, which are near each other at all times, leads to the repeated contact and full coalescence of the separated droplets. The abnormality is attributed to the competition between the motions of the droplets and the tiny liquid bridge that connects the droplets. The influence of the surface structures of substrates, especially carbon nanotubes, on the formation behavior is discussed by analyzing the mean square displacement, velocity fields, and density and scaling profiles. This study provides guidance for controlling drop formation behavior by regulating the surface structures of carbon substrates. Full article

Background: The influence of digital media on public perception of sexual health is significant and relates to its effects on knowledge, attitudes, and behaviors. Motion graphics and animation represent a novel innovation in health-related communication. The visual attractiveness and adaptability to cultural issues offer an alternative means of conveying often sensitive issues. This systematic review aimed to provide an overview of their efficacy in delivering sexual health messages and to identify the components contributing to success. Methods: A literature search was conducted using Scopus, MEDLINE (via PubMed), and DOAJ, covering studies from inception to 31 August 2025. All eligible studies included randomized controlled trials, quasi-experimental studies, and other evaluations, which were synthesized by outcomes related to knowledge, attitudes, behaviors, intentions, and/or psychosocial well-being. The study was pre-registered on the INPLASY platform (INPLASY202580073). Results: Eleven studies published between the years 1989 and 2025 met the inclusion criteria. The majority reported improvements in sexual health knowledge and attitudes, and several studies also demonstrated improved behaviors and psychosocial well-being. Factors that contributed to interventions that have been successful were cultural adaptation, being based on theory, and presentation over time. Conclusions: Motion graphics and animation, therefore, represent an exciting means of sexual health promotion and stigma reduction. Future studies should therefore focus on the determination of standardized formats for media presentations, the evaluation of long-term effects, and the evaluation of cost–benefit to enhance the effectiveness of media communication in health promotion. Full article

This paper addresses the challenge of cooperatively escorting a moving underwater target, such as a human-occupied vehicle (HOV), using a multi-AUV formation in complex ocean environments. We propose a comprehensive framework, RG-SAPF scheme, that integrates a rigidity graph (RG)-based reconfigurable formation control strategy with a safe artificial potential field (SAPF) motion planning method. The RG-based controller enables the AUVs to form and dynamically reconfigure a 3D escort formation around the target using only relative position information, ensuring the target remains within the formation’s convex hull. Meanwhile, the SAPF algorithm, enhanced with an adaptive Widrow–Hoff rule, enables real-time and collision-free path planning in obstacle-rich environments. Simulation and experimental results demonstrate that the proposed method effectively maintains formation integrity, supports flexible obstacle avoidance, and provides continuous target escort under dynamic conditions, validating its potential for practical underwater escort applications. Full article

The utilization of hydrocyclones dates back more than a century. As the key channel for multiphase flow, the inlet chamber exerts a notable influence on the separation efficiency of hydrocyclones. Conventional feed bodies mainly adopt straight lines as guidelines. During the transition of fluid from linear motion to circumferential motion, significant kinetic energy loss and particle misalignment are exhibited, resulting in relatively low classification accuracy of the hydrocyclone. Therefore, in this study, a hydrocyclone featuring a complex curved inlet chamber structure was designed, and numerical analysis was employed to examine the particle distribution and aggregation characteristics within both the inlet chamber and the hydrocyclone. Supplemented with RSM/VOF/TFM simulations and quartz sand experimental validation, this study compares the separation performance of the complex curved inlet with the conventional linear inlet. The results indicate the following: when particle sizes are small, particles are dispersed throughout the hydrocyclone and inlet chamber, exhibiting a disordered state, which leads to poor classification performance. As particle size increases, particles gradually form layers along the radial direction; larger particles tend to accumulate on the hydrocyclone wall. When the particle concentration is maintained within a specific range, it promotes the migration of fine particles toward the center, thereby reducing the likelihood of fine particles entering the outer vortex and allowing for more precise classification of fine particles. As the particle concentration increases, the cutting ability of the hydrocyclone progressively diminishes; when the concentration exceeds 20%, the maximum underflow recovery rate for particles smaller than 50 µm is only 60%, resulting in significant coarse overflow and a notable decrease in classification precision. Furthermore, as the inlet concentration increases, the dispersion index for 0.5 µm particles ranges from 0.6 to 1.6, for 4 µm particles from 0.6 to 1.4, and for 60 µm particles from 0.6 to 1. The decreasing dispersion index indicates an increasing classification force, which aids in the formation of a coarse particle layer on the wall. The conclusions and data obtained provide a theoretical foundation and empirical support for the design of innovative inlet chamber structures. Full article

This paper presents Macalla, a practice-based research project investigating how architectural spaces function as co-creative instruments in Ambisonic choral composition. Comprising four original compositions, Macalla employed Nelson’s praxis model, integrating creative practice with critical reflection through iterative cycles of composition, anechoic vocal recording, and site-specific re-recording. The project explored six contrasting architecturally significant spaces including a gaol, churches, and civic offices. Using a stop-motion stem playback methodology, studio-recorded vocals were reintroduced to architectural spaces, revealing emergent sonic properties that challenged compositional intentions and generated new musical possibilities. The resulting Ambisonic works were disseminated through multiple formats including VR/360 video via YouTube, Octophonic concert performance, and immersive headphone experiences to maximize accessibility. Analysis of listener behaviours identified distinct engagement patterns, seekers actively hunting optimal positions and dwellers settling into meditative reception, suggesting spatial compositions contain multiple potential works activated through listener choice. The project contributes empirical evidence of acoustic agency, with documented sonic transformations demonstrating that architectural spaces actively participate in composition rather than passively containing it. This research offers methodological frameworks for site-specific spatial audio creation while advancing understanding of how Ambisonic technology can transform the composer-performer-listener relationship in contemporary musical practice. Full article

We investigate the effect of general relativity on the Sitnikov problem. The Sitnikov problem is one of the simplest three-body problems, in which the two primary bodies (a binary system) have equal mass m and orbit their barycenter, while the third body is treated as a test particle under Newtonian gravity. The trajectory of the test particle is perpendicular to the orbital plane of the binary (along z-axis) and passes through the barycenter of the two primaries. To study the general relativistic contributions, we first derive the equations of motion for both the binary and the test particle based on the first post-Newtonian Einstein–Infeld–Hoffmann equation, and integrate these equations numerically. We examine the behavior of the test particle (third body) as a function of the orbital eccentricity of the central binary e, the dimensionless gravitational radius $\lambda$, which characterizes the strength of general relativistic effect, and the initial position of the test particle ${\overline{z}}_0$. Our numerical calculations reveal the following; as general relativistic effects $\lambda$ increase and the eccentricity e of the binary orbit grows, the distance $\overline{r}$ between the test particle and the primary star undergoes complicated oscillations over time. Consequently, the gravitational force acting on the test particle also varies in a complex manner. This leads to a resonance state between the position $\overline{z}$ of the test particle and the distance $\overline{r}$, causing the energy E of the test particle to become $E\ge 0$. This triggers the effective ejection of the test particle due to the gravitational slingshot effect. In this paper, we shall refer to this ejection mechanism of test particle as the “Sitnikov mechanism.” As a concrete phenomenon that becomes noticeable, the increase in general relativistic effects and the eccentricity of the binary orbit leads to the following: (a) ejection of test particles from the system in a shorter time, and (b) increasing escape velocity of the test particle from the system. As an astrophysical application, we point out that the high-velocity ejection of test particles induced by the Sitnikov mechanism could contribute to elucidating the formation processes of astrophysical jets and hyper-velocity stars. Full article

A notable decline in the frequency of sea fog inflows and an increase in low-cloud ceiling height were observed following the construction of the Saemangeum Seawall west of the Gunsan Airport, an area traditionally prone to frequent sea fog events. To the mechanisms underlying these changes, a numerical experiment was conducted using the Weather Research and Forecasting model. An 11-m-high seawall was used as a physical barrier, and an elevated sea surface temperature (SST) was established within the enclosed area to simulate realistic post-construction conditions. The model successfully reconstructed sea fog occurrences, and the cloud–water mixing ratio effectively captured the spatial distribution of sea fog. Deviations from the control experiment showed a consistent pattern of reduced cloud–water mixing ratios near the surface and enhanced concentrations at high levels. Decreased buoyancy frequency in the surface layer enhanced atmospheric instability, inducing upward motion and intensified condensation activity. Increases in the turbulence kinetic energy within the planetary boundary layer (TKE within the PBL), vertical wind shear, and temperature further corroborated the reduction in sea fog and enhanced stratus formation. These findings indicate that the increased SST and seawall significantly influence the modification of the sea fog structure and its inflow dynamics. Full article

Molecular dynamics simulations of nanoindentation were conducted to compare the dislocation behavior in a pure V and a TiVTa multi-principal element alloy (MPEA) with [100] and [111] crystal orientations. It is found that the significant resistance to dislocation motion and loop formation in the TiVTa MPEA compared to pure V, attributed to its substantial lattice distortion. While dislocation nucleation was heterogeneous in both materials with similar activation volumes and nucleation stresses (approximately 0.2 G), the dislocation density and plastic zone volume in TiVTa were substantially lower. Under standard indentation conditions, independent dislocation loops readily formed in pure V but were absent in TiVTa. With a larger indenter size and a greater nanoindentation depth, the results demonstrated that forming loops in TiVTa requires significantly higher force, directly linking this effect to the hindrance of dislocation glide by chemical disorder and lattice distortion. This study provides atomic-scale insights into the deformation mechanisms of TiVTa MPEAs, offering guidelines for future alloy design. Full article

Impact butt joining of copper 5 mm thick C1100 and aluminum alloy A6061-T6 plates was carried out, according to a method recently devised by one of the authors. The joining method results in newly created surfaces being obtained by very large plastic deformation under high-speed conditions, wherein the two materials are subjected simultaneously to compression and a high-speed sliding motion. The new surface of C1100 is created by expansion, whereas for A6061-T6, the new surface is created by removal of the softened surface layer. This layer forms a foil, which is extruded from the joining interface by the compressive force. Using a high-speed video camera, the formation of the foil was observed to take place even in the early stages of deformation. The distribution of joint efficiency was evaluated by examining the joint boundary. When the compressive force increased, some specimens fractured in the C1100 region. The zone affected by the joining process was highly limited, to within 0.8 mm of the boundary; i.e., 20% of the plate thickness. The thickness of the joined plate was reduced by repetitive rolling operations, in which the true strain was about −1. This indicates that the layer of the intermetallic compounds is very thin. Once rolled, the joined sheet exhibited a maximum joint efficiency of 99.3%. In cases where the joining efficiency exceeded 80%, the main region exhibiting fracturing was in the A6061-T6 alloy. Full article

This paper investigates the cooperative path-following control problem for multiple unmanned aerial vehicles (UAVs) under Global Navigation Satellite System (GNSS) denial conditions. To achieve equidistant distribution and uniform velocity motion within the swarm, a distributed control strategy based on Linear Matrix Inequalities (LMI) is proposed. Additionally, a novel virtual arc-length cooperation strategy is introduced, decomposing the formation maintenance problem into two subtasks: path following and velocity synchronization. This approach reduces control complexity and significantly minimizes frequent velocity cooperation issues caused by angular separation errors. To enable online estimation and compensation for model uncertainties and external disturbances, a USDE is incorporated, offering enhanced adaptability to time-varying disturbances. Simultaneously, a dynamic event-triggered mechanism (ETM) is designed to exchange neighbor information only when necessary, substantially reducing communication load. Global consistent ultimately bounded stability of the closed-loop system is rigorously proven using Lyapunov theory. Finally, validation results from the simulation platform demonstrate the proposed method’s certain feasibility and effectiveness in practical applications. Full article

A continuum model for describing pseudo-turbulent flows of a dispersed phase is developed using a statistical approach based on the kinetic equation for the probability density of particle velocity and temperature. The introduction of the probability density function enables a statistical description of the particle ensemble through equations for the first and second moments, replacing the dynamic description of individual particles derived from Langevin-type equations of motion and heat transfer. The lack of detailed dynamic information on individual particle behavior is compensated by a richer statistical characterization of the motion and heat transfer within the particle continuum. A numerical simulation of the unsteady flow of a gas–particle suspension generated by the interaction of a shock wave with a particle cloud is performed using an interpenetrating continua model and equations for the first and second moments of both gas and particles. Numerical methods for solving the two-phase gas dynamics equations—formulated using a two-velocity and two-temperature model—are discussed. Each phase is governed by conservation equations for mass, momentum, and energy, written in a conservative hyperbolic form. These equations are solved using a high-order Godunov-type numerical method, with time discretization performed by a third-order Runge–Kutta scheme. The study analyzes the influence of two-dimensional effects on the formation of shock-wave flow structures and explores the spatial and temporal evolution of particle concentration and other flow parameters. The results enable an estimation of shock wave attenuation by a granular backfill. The extended pressure relaxation region is observed behind the cloud of particles. Full article

Aiming at the problem that obstacle avoidance flexibility and formation integrity are difficult to coexist in multi-robot formation motion, a path-deformation mapping mechanism is proposed, which deeply integrates artificial potential field and affine transformation, and drives formation adaptive adjustment in real time through path information. By using the non-uniform scaling characteristics of the affine transformation, the limitation of traditional conformal transformation is broken through, and the unity of flexibility and integrity is realized. The effectiveness of the algorithm is verified by experiments, which provide a practical solution for cooperative obstacle avoidance of multi-robot systems in complex environments. In order to verify the performance of the algorithm, a numerical simulation is carried out, and an experimental platform composed of seven omnidirectional mobile robots is built for physical verification. The simulation and experimental results show that the formation can complete the obstacle avoidance task in the complex static obstacle environment, and the average formation tracking error is maintained below 0.05 m. Compared with the traditional local obstacle avoidance or formation switching method, this algorithm significantly improves the fluency of the obstacle avoidance process and the integrity of the formation while ensuring a success rate of 100% obstacle avoidance. Full article

This study explores the use of construction robots with collaborative path planning and coordination in complex building construction tasks. Current construction processes involving robots are often fragmented due to their single-task focus, with limited research focused on employing multiple construction robots to collaboratively perform tasks. To address such a challenge, this research proposes an improved A* algorithm for global path planning and obstacle avoidance, combined with the development of a BIM-based grid map of the construction site. The leader–follower method is utilized to guide the robot group in maintaining an optimal formation, ensuring smooth collaboration during construction. The methodology includes formalizing building construction site environments into BIM-based grid maps, path planning, and obstacle avoidance, which allows robot groups to autonomously navigate and complete specific tasks such as concrete, masonry, and decoration construction. The results of this study show that the proposed approach achieves significant reductions in pathlength and operational time of approximately 9% and 10%, respectively, while maintaining safety and efficiency compared with traditional manual methods. This research demonstrates the potential of collaborative construction robot groups to enhance productivity, reduce labor costs, and provide a scalable solution for the intelligent transformation of the construction industry; extends the classical A* algorithm by incorporating obstacle density into the heuristic function; and proposes a new node simplification strategy, contributing to the literature on robot motion planning in semi-structured environments. Full article

The Messara Basin, a critical agricultural region in Crete, Greece, faces escalating geohazards, particularly land subsidence driven by intensive groundwater abstraction. Historical radar interferometry (1992–2009) indicated subsidence up to 20 mm·yr⁻¹, while recent European Ground Motion Service data (2016–2021) show mean vertical velocities reaching −31.2 mm·yr⁻¹. This study provides the first integrated hydrogeological assessment for the Basin, based on systematic field surveys, borehole inventories, and four coordinated campaigns (2021–2023) that established a basin-wide monitoring network of 767 stations. The dataset supports delineation of recharge zones, identification of potentiometric depressions, and mapping of aquifer-stress areas. Results show strong seasonality and extensive cones of depression, with local heads declining to ~−50 m below sea level. Land-use change (1990–2018 CORINE data; 2000–2020 agricultural censuses) combined with updated geological mapping highlights the vulnerability of post-Alpine formations, especially Quaternary and Plio–Pleistocene deposits, to deformation. The combined evidence links pumping-induced head decline with spatially coherent subsidence, delineates hotspots of aquifer stress, and identifies zones of elevated compaction risk. These findings provide a decision-ready baseline to support sustainable groundwater management, including enhanced monitoring, targeted demand controls, and managed aquifer-recharge trials. Full article

This study investigates the role of toroidal vortex formation in torque-flow pumps and its influence on pump performance. A mathematical model of viscous fluid motion in toroidal coordinates was developed to describe the two-stage energy transfer mechanism, in which the impeller drives the toroidal vortex and the vortex subsequently imparts momentum to the main throughflow. The model identifies vortex deformation as a primary source of hydraulic losses. The theoretical framework was validated by computational fluid dynamics (CFD) simulations of a torque-flow pump. Analysis of the axial, circumferential, and vertical velocity components revealed a closed three-dimensional toroidal circulation loop within the free chamber, confirming the predictions of the mathematical model. A parametric study was conducted to assess the influence of impeller extension into the free chamber (Δb₂) on pump performance. Three characteristic regimes were identified. At Δb₂ ≈ 6 mm, the shaft power decreased to 120.3 kW (an 8.1% decrease compared to the baseline), with efficiency improving to 39.2%. At Δb₂ ≈ 10 mm, the pump achieved its best balance of parameters: efficiency increased from 34.0% to 42.8% (+8.7 percentage points), while head rose from 32.8 m to 38.5 m (+17.4%), with moderate power demand (122.3 kW). At Δb₂ ≈ 70 mm, the head reached 45.6 m (+39%), but power consumption rose to 146.9 kW (+12%), and the design shifted toward centrifugal-type operation, reducing reliability for abrasive fluids. Overall, the results provide both a validated mathematical description of toroidal vortex dynamics and practical guidelines for optimizing torque-flow pump design, with Δb₂ ≈ 10 mm identified as the most rational configuration. Full article