Search Results (453)

The present study demonstrates the use of a transient multiphase flow model for the description of feed rod melting dynamics during the floating-zone silicon crystal growth process on a local scale. The presented numerical model is verified using a previously introduced analytical model of the thin melt layer on the open melting front. An artificial increase in viscosity on the liquid–gas boundary is used to minimize numerical effects, and good agreement with the analytical model is achieved in the system parameter range that describes a typical growth process. Simulations with a precise interface shape show that a stable solution is achieved in cases with different initial melt distributions, showcasing the re-establishment of melt flow after the thin melt layer breaks. The influence of flow rate fluctuations is investigated, and the obtained stable solution is maintained in the majority of the considered cases. Full article

Urban Building Energy Modeling (UBEM) offers a scalable, physics-based method to simulate energy demand at the district level, enabling data-driven district energy demand planning and optimization. However, translating UBEM into a reliable, openly replicable workflow remains a significant methodological gap. In particular, limited attention has been devoted to the development of transparent and transferable UBEM workflows capable of systematically quantifying the impact of modeling assumptions on district-scale thermal demand accuracy. This paper presents and validates a five-step UBEM pipeline integrating freely available geospatial data from OpenStreetMap (OSM), archetype-based building characterization, multi-scenario EnergyPlus simulation via the Urban Modeling Interface (UMI) within a structured validation framework. To improve interpretability and reproducibility, a dedicated three-scenario simulation protocol was developed to isolate and quantify the influence of geometry simplifications, archetype assumptions, and weather data fidelity on model accuracy. The workflow is demonstrated through application to a real district heating system (DHS) in northern Italy, encompassing UBEM results validated against monitored consumption data at different temporal resolutions. The refined model achieves a district-scale annual magnitude error of 1.30% between real and simulated data. Persistent limitations in domestic hot water representation and peak load estimation are identified as priorities for future development. Full article

In this study, to address the overlying strata control issue for the isolated working face of a super-thick coal seam confined by surrounding goafs and open-pit boundaries, we focus on mining via upward slicing strip paste filling in a Ningxia coal mine. We adopt strip coal pillar stability theory for safety factor analysis and conduct FLAC3D three-dimensional numerical simulations to quantitatively reveal overlying strata displacement, stress redistribution, plastic zone evolution, and surface subsidence response. Our theoretical calculations show that, when the mining width is 5 m, the safety factors of retained coal pillars with widths of 5, 10, and 15 m are <1, 1.3, and 1.8, respectively. Our numerical results indicate that the overlying strata of the first slice are dominated by continuous bending subsidence, with a maximum vertical displacement of 21.4 cm, increasing to 55.5 cm after four slices without through damage. High stress is mainly controlled by mined-out area boundaries and inter-face coal pillars, with the maximum principal stress of the fourth slice reaching 18.9 MPa. The surface subsidence center stably corresponds to the underlying backfill goaf, with a maximum value of 11.4 cm. Our research demonstrates that slicing strip filling can suppress deformation and stress concentration risks by reconstructing load transfer and realizing synergistic bearing, as reflected by the limited surface subsidence of 11.4 cm, the controlled maximum principal stress of 18.9 MPa, and the improved coal pillar safety factor from <1 to 1.3–1.8 under wider retained pillars, providing a basis for optimizing strip pillar width and mining–filling parameters. Full article

Population aging and the rising prevalence of motor disorders are driving demand for assistive lower-limb robotic systems capable of decoding user intention rather than merely providing mechanical support. We present CM-FuseNet, an attention-augmented hybrid Brain–Computer–Muscle Interface (BCMI) that simultaneously fuses cortical concentration indices extracted from electroencephalography (EEG) and lower-limb intention patterns derived from electromyography (EMG) to adaptively control a 4-DOF assistive lower-limb exoskeleton. To eliminate the burden of human-subject ethics review and to ensure reproducibility of the proposed methodology, all validation is performed exclusively on (i) permissively licensed open-access biomedical datasets, (ii) high-fidelity OpenSim 4.5 and MuJoCo 3.1 musculoskeletal–exoskeleton co-simulation, and (iii) limited self-experimentation by the corresponding author with non-invasive consumer-grade devices. Three components are introduced: (i) a log-tanh normalized concentration index CI in (0, 1) derived from the $(P_{SMR}+P_{Mid-Beta})/P_{Theta}$ ratio; (ii) a bidirectional Cross-Modal Transformer (CMT) with eight-head self- and cross-attention; and (iii) a Soft Actor-Critic (SAC) reinforcement-learning controller that adaptively tunes four servo PID gains using a concentration-weighted state. Experiments on the PhysioNet EEGMMIDB, Ninapro DB2/DB7, HuMoD and WAY-EEG-GAL datasets (combining N = 162 trial sessions, 47,520 windows, and five-fold cross-validation) yield a gait-phase classification accuracy of 96.84 ± 1.18%, torque-tracking RMSE of 0.072 ± 0.008 N·m, information transfer rate of 38.6 bits/min, end-to-end latency of 9.4 ms, and a 27.4% reduction in simulated metabolic cost over an EMG-only PID baseline (one-way ANOVA: F(4, 75) = 47.83, p < 0.001; Tukey HSD: p < 0.01 against all baselines). Under high cognitive load, CM-FuseNet preserves accuracy with only a 4.63 percentage-point degradation versus 13.22 percentage points for the EMG-only baseline. Full article

Contemporary artificial intelligence systems present themselves through the aesthetic of openness: a clean interface, a blinking cursor, an implicit invitation to bring whatever one wishes. This essay argues that this appearance conceals a structural inversion. Drawing on phenomenological philosophy, particularly the work of Simone Weil, Jean-Luc Marion, Jacques Derrida, Henri Bergson, and Byung-Chul Han, alongside a technical account of transformer architecture and large language model training, the essay distinguishes two fundamentally different modes of openness, understood throughout as modes of relation to what arrives rather than as properties of objects: privative emptiness, defined by what it lacks and oriented toward resolution, and receptive openness, a positive capacity for availability toward what cannot be anticipated or controlled. At every structural level, from interface design through training objectives to core architecture, AI systems are constitutively oriented toward the former while producing a phenomenologically convincing simulation of the latter. Engaging Jean Baudrillard’s concept of the simulacrum, the essay argues that this simulation, at sufficient scale and ubiquity, risks eroding the human capacity to distinguish genuine receptive openness from its engineered appearance. The paper concludes by gesturing toward contemplative and institutional counter-practices, including the author’s work on Radical Pause: The UCCS Stillness Project, as responses to this formative challenge, and specifies the structural conditions under which such practices resist commodification by the very attention economy they oppose. Full article

Achieving precise, untethered manipulation at the millimeter scale remains a fundamental challenge in minimally invasive medicine. Magnetic milligrippers have emerged as promising untethered tools for grasping, transporting, and releasing objects in confined anatomical environments, yet most existing rigid designs rely on multi-component assemblies with dedicated hinges or joints that require complex fabrication processes. Here, we present a simple, cost-effective rigid magnetic milligripper based on a folded titanium structure with two inclined permanent magnets. Actuated by a three-axis Helmholtz–Maxwell coil system, it enables orientation and translation control, as well as reversible opening. The actuation platform is coupled to a joystick-based control interface, allowing intuitive, real-time steering and opening of the milligripper by a single operator. The design is established with an analytical magnetic dipole model and validated through both finite-element simulations and experimental characterization, which together confirm reproducible, fully elastic operation across the investigated actuation range. The strong agreement between analytical, numerical, and experimental results establishes this architecture as a mechanically robust and scalable proof-of-concept platform for magnetic micromanipulation, with direct relevance to future minimally invasive biomedical applications. Full article

The coupled characterization of overburden movement, surrounding-rock failure evolution, and mine-pressure response remains difficult during high-intensity longwall mining because these processes are commonly measured and interpreted using separate data streams. In this study, a multi-source sensing and interpretation framework was established for the S8310 longwall face of Yangmei No. 1 Mine by integrating physical similarity simulation, underground monitoring, UDEC numerical modeling, region-of-interest (ROI) image-feature extraction, and sliding-window long short-term memory (LSTM) analysis. Fiber Bragg grating (FBG) sensors and conventional monitoring were used to obtain key-stratum deformation and support-pressure responses. A joint-state-based damage index (DI) was constructed from fixed-ROI UDEC outputs to quantify progressive structural activation beneath the key stratum. The results indicate that the overburden evolved from global bending and local crack initiation to fracture expansion, interface degradation, and interlayer slip. In the physical model, the initial weighting interval was approximately 37.5 cm, and the periodic weighting intervals were mainly 13.3–15.7 cm; these correspond to prototype-scale distances of approximately 37.5 m and 13.3–15.7 m, respectively. Peak abutment pressure occurred approximately 9–17 cm ahead of the face at the model scale, with a peak coefficient of 1.40–1.68. When the prototype advance distance increased from 37.5 m to 80.3 m, the ROI exhibited enhanced joint activation and a transition from local slip to continuous tensile opening and slip. For the pressure-sequence analysis, the 24-step-window LSTM produced lower errors than the 36- and 48-step-window LSTM models under the same preprocessing and training settings. Additional persistence, moving-average, and random forest baselines were added to clarify the prediction context: the persistence baseline performed strongly because of the high short-term autocorrelation of the pressure series, whereas the 24-step-window LSTM outperformed the moving-average and random forest baselines. Accordingly, the LSTM module is interpreted as an auxiliary temporal-pattern identification tool rather than as an exclusive optimal predictor. The comparison between DI evolution and pressure-prediction behavior suggests that rapid DI growth is mechanically consistent with stronger pressure-sequence non-stationarity and increased prediction deviation near active mine-pressure events. The proposed framework provides a sensor-oriented and physically interpretable approach for linking overburden failure evolution with mine-pressure response in longwall mining. Full article

Agricultural soil contact components, including ploughshares, rotary blades, and furrow openers, form the active interface between machinery and complex field media. Operating in multiphase environments, these tools face severe abrasive wear, impact fatigue, and interfacial adhesion. These destructive forces irreversibly alter edge geometry and drastically degrade macroscopic operation quality. This review integrates tillage and precision seeding components into a unified tribological framework. It highlights the nonlinear relationship between microscopic material removal and geometric edge retention. Profile degradation is heavily dictated by soil texture, where sandy soils cause micro-cutting, clay soils induce severe adhesion, and gravelly soils produce impact fracture. To predict these complex wear behaviours accurately, coupled multiphysics numerical simulation using the discrete element method for particle flow dynamics and finite element analysis for transient contact stress provides a highly robust methodology. Mitigating these failures requires a functionally zoned surface engineering approach. Carbide hardfacing offers localized abrasion resistance, while polymer composite layers and bionic nonsmooth structures effectively interrupt continuous liquid films in wet cohesive soils. Ultimately, integrating online multidimensional sensing with full life cycle digital-twin models represents the future trajectory for developing adaptive and highly durable agricultural equipment. Full article

Vision–Language–Action (VLA) policies are increasingly evaluated on language-conditioned robotic manipulation benchmarks, but success rate alone often obscures runtime-interface alignment, the repeatability of observation-degradation effects, and the recovery-relevant semantics of failures. This study proposes ROEP (Robotics-Oriented Evaluation Protocol), a VLA-targeted deployment-oriented evaluation protocol that converts rollout outcomes into claim-level evidence for closed-loop robotic manipulation. ROEP first verifies clean-condition evaluability and runtime fidelity of the sensor-to-action execution interface, then evaluates controlled visual perturbations, repeated-run reference variability, timeout-dominant failures, and recovery/shield support. We apply ROEP to OpenVLA, X-VLA, and VLA-Adapter on eight LIBERO Goal and Object tasks, producing a 24-row evaluation matrix with complete clean and medium-perturbation evidence. Under the evaluated LIBERO simulation setting, the results show that runtime-interface fidelity and checkpoint provenance are important for interpreting X-VLA and OpenVLA Object results, while VLA-Adapter maintains strong Goal-suite performance but exhibits a substantial Object-suite clean-to-perturbation drop dominated by timeout termination. ROEP therefore clarifies which deployment-relevant claims are supported, withheld, or insufficiently evidenced by the available rollouts without certifying open-world deployment safety or recovery success. The protocol complements existing VLA benchmarks by reporting success rate together with runtime fidelity, repeatability, failure semantics, and recovery/shield support evidence. Full article

Custom-built quadrupedal platforms offer an accessible path for robotics research, yet researchers frequently encounter a “framework gap” when porting complex open-source control software to custom hardware. This paper documents the integration and validation process of Scotty, a custom quadrupedal robot, evaluating two distinct open-source control frameworks: the torque-based MIT Mini Cheetah and the position-based CHAMP architectures. Due to minimal documentation, hardware-dependent complexities, and a tightly coupled architecture, it was difficult to achieve a satisfactory result using the MIT framework within our system’s scope. Conversely, CHAMP’s structured integration documentation enabled the deployment of a locomotion pipeline validated in Gazebo simulation alongside a functional hardware interface middle layer. To overcome CHAMP’s lack of native operational state management, we developed a custom state-based controller with a web-based GUI that safely orchestrates transitions across Idle, Ready, Down, Stand, and Walk configurations. While walking was successfully validated in the simulation environment to verify the control software pipeline, physical hardware evaluation was restricted to individual joint control, localized leg movements, and GUI-based parameter tuning. Full closed-loop hardware locomotion was not achieved, as the extensive tuning of gait parameters and controller gains under full system weight was bounded by project constraints. The integration logs, practical hurdles, and architectural lessons documented in this work are shared openly to provide a clear, transferable roadmap for future developers of robotic systems. Full article

Osteochondral defects, involving both articular cartilage and subchondral bone, can lead to joint degeneration and osteoarthritis. Recent advances in 3D-printed biphasic scaffolds offer promising opportunities to recreate physiological microenvironments for tissue regeneration. In tissue engineering, these scaffolds can be mechanically stimulated to promote targeted cartilage and bone formation. While computational models have been widely used to study mechanically induced cellular responses in monophasic scaffolds, time-dependent modelling of biphasic osteochondral systems remains relatively scarce. In this study, a fluid–structure interaction (FSI) framework coupled with a mechanoregulatory algorithm was developed to predict mechanically induced early-stage mesenchymal stem cell (MSC) differentiation in biphasic open-porous osteochondral scaffolds comprising chondral and bone layers designed for direct ink writing (DIW). In a second model, an interfacial barrier layer representing the native osteochondral interface was integrated. Dynamic compressive loading (1 Hz, $2.5\%$ strain) was applied. The simulations predicted region-specific differentiation patterns in both the chondral and subchondral bone regions. In the scaffold without a barrier layer, approximately $68.9\%$ of MSCs in the chondral layer and $93.4\%$ of MSCs in the bone layer underwent chondrogenic and osteogenic differentiation, respectively. Incorporation of the barrier layer caused only minor changes, reducing predicted cartilage and bone differentiation by approximately $1.5\%$ and $3.9\%$, respectively. Overall, this study highlights the capability of computational modelling to predict mechanobiological responses in complex osteochondral systems and support scaffold design and effective mechanical stimulation protocols. Full article

Active ripple suppression branches (ARSBs) are widely employed in switching power converters interfacing ripple-sensitive devices such as batteries, supercapacitors, hydrogen electrolyzers, fuel cells, and photovoltaic panels. Conventional ARSBs share the main converter DC-link voltage and require inductance comparable to that of the primary power stage, resulting in high semiconductor voltage stress and bulky magnetic components. Recent studies have proposed supplying the ARSB from a lower auxiliary voltage source, significantly reducing both inductance value and semiconductor voltage ratings. This paper shows, however, that lowering the ARSB rating while keeping the series capacitance value unaltered inherently increases residual current ripple, degrading ripple-cancellation performance. It is then demonstrated that this limitation should be overcome by increasing the ARSB capacitance in inverse proportion to the rating reduction, thereby restoring ripple suppression performance. Furthermore, it is revealed that for converters operating at a fixed duty cycle, a unique operating point exists where the ARSB capacitor can be eliminated without sacrificing the ripple attenuation ability of the circuit. The resulting capacitorless implementation reduces component count, size, complexity, and cost while improving ripple suppression. Simulation and experimental results validate the theoretical analysis and confirm the feasibility and effectiveness of the proposed capacitorless open-loop operating ARSB. Full article

Smart microgrids combining photovoltaic arrays, wind turbines, and battery storage generate telemetry that existing open-source monitoring tools cannot process with per-mechanism energy loss visibility in real time. This paper presents the design, implementation, and evaluation of an IoT monitoring framework. The framework incorporates a physics-based microgrid simulator, a hierarchical MQTT communication architecture, and a React-based web-based user interface that supports WebSocket-based real-time data visualization. The framework consists of ten containerized microservices that can be started with a single command: docker compose up -d. All stack performance testing was conducted using a simulated 1 h test case based on a 100 kWp PV system, 10 kW wind turbine, and 50 kWh battery-powered campus microgrid. Median P50 publisher-to-subscriber latency was 27.2 ms and 99th percentile (P99) latency was 48.3 ms, with 100% message delivery across 5840 test messages, with per-topic analysis revealing a 25 ms serialization-order effect in sequential MQTT publishing. Comparative analysis against nine existing platforms including OpenEMS, VOLTTRON, Eclipse Ditto, and pymgrid confirms that, among the platforms surveyed, none unifies physics-based loss telemetry, IoT communication, time-series storage, and real-time visualization in a single reproducible deployment. Full article

This paper presents a risk-averse information-gap decision theory (IGDT)-based day-ahead scheduling framework for active distribution networks with high penetration of inverter-interfaced resources. The proposed day-ahead strategy coordinates active and reactive power scheduling in an active distribution network comprising renewable generation, diesel units, demand-side management, electric vehicle charging stations, and energy-storage-equipped soft open points. The corresponding deterministic operating condition is then used as the reference state for uncertainty analysis. The scheduling problem is formulated as a mixed-integer nonlinear programming (MINLP) model considering network operating constraints and voltage-dependent load characteristics. Uncertainty associated with load demand and renewable generation is addressed using the IGDT risk-averse approach to quantify admissible uncertainty. The proposed methodology is implemented on a modified IEEE 33 bus distribution system considering deterministic operation, load-demand uncertainty, renewable-generation uncertainty, and simultaneous uncertainty in both load demand and renewable generation. The optimization model is developed in GAMS and solved using the DICOPT solver. The simulation results demonstrate the capability of the proposed framework to accommodate simultaneous load-demand and renewable-generation uncertainty within a predefined operating-cost threshold while maintaining secure network operation. Full article

Accurate water holdup measurement in oil–water flows remains challenging due to flow-regime-dependent dielectric distributions and the limited sensitivity of conventional amplitude- or phase-based sensing features. This paper proposes a curved microstrip transmission-line sensor that jointly exploits broadband scattering responses and resonance-frequency shifts to characterize water holdup. The curved geometry increases the effective electrical length within a compact footprint, strengthens field interaction with the surrounding medium, and introduces resonance behavior within the operating band. To improve the physical consistency of numerical modeling, the frequency-dependent complex permittivity of oil–water mixtures is experimentally measured using an open-ended coaxial probe and directly incorporated into full-wave electromagnetic simulations. Both emulsion and stratified oil–water conditions are investigated through simulation and experimental validation. The results show that, under emulsion conditions, the magnitude and phase of S₁₁ and S₂₁ exhibit clear monotonic responses to water holdup. Under stratified conditions, conventional magnitude and phase features exhibit reduced resolution due to the spatially non-uniform dielectric distribution. In this case, variations in water holdup primarily modify the interface position rather than the overall dielectric volume, resulting in relatively small perturbations to the effective permittivity experienced by the guided electromagnetic field. Nevertheless, the resonance frequency remains highly sensitive and shifts monotonically with water holdup. The proposed sensor combines a resonant frequency with broadband magnitude and phase responses, where the resonant frequency provides a stable and reliable indicator across different flow conditions. The results demonstrate the potential of curved microstrip transmission-line structures for compact and reliable water holdup measurement in complex oil–water flow environments. Full article