Search Results (5,480)

Distributed optical fiber sensing (DOFS) based on phase-sensitive optical time-domain reflectometry ($\mathsf{\varphi }$-OTDR) is increasingly used for perimeter and pipeline monitoring, yet most recognizers are evaluated as closed-set classifiers, whereas a deployed fiber also records nuisance sources and event types absent from training. In our experiments, a closed-set recognizer with 0.999 accuracy still gives a false-alarm rate (FAR) of 0.42–0.64 on simulated unknown nuisance classes, and a conformal threshold calibrated only on known negatives does not remove this failure. We therefore propose Physically Consistent Risk Calibration (PCRC), which combines a label-free physical-consistency gate computed from spatial compactness, common-mode ratio, and signal-to-noise ratio (SNR) with a conformal threshold for gate-passing negatives and a three-level alarm/review/discard decision. The guarantee is conditional: conformal calibration controls gate-passing negatives under exchangeability, and the gate removes only physically inadmissible nuisance windows. On three public distributed acoustic sensing (DAS) field datasets, the known-negative FAR follows the target level when calibration and test negatives are exchangeable, held-out threat coverage reaches 0.87 and 0.68 on the two multichannel corpora, and every physically admissible held-out nuisance passes the gate and requires recalibration from verified field negatives. In a controlled simulation whose unknown nuisance classes are constructed to be inadmissible, PCRC produces no observed automatic false alarms while retaining 0.998 known-threat recall. Full article

The worsening jobs–housing imbalance in high-density urban areas has become increasingly prominent. However, existing studies predominantly focus on the city and regional scales, with limited attention to small-scale spatial units, failing to provide empirical evidence for refined regulation of transport and land use. As a typical compact development mode at the small scale, Transit-Oriented Development (TOD) offers an ideal spatial unit for examining micro-level jobs–housing relationships. However, its influence on jobs–housing balance remains unclear. This study takes 72 built subway station areas in Shenzhen’s highest-density built-up area as the research object. Employing quadratic polynomial regression and XGBoost-SHAP methods, it reveals the effects of transportation supply and land use on the employment–residential ratio, as well as threshold effects and indicator synergies. The main findings are as follows: (1) Transportation supply (Node), land use (Place), and TOD degree (TODness) all exhibit U-shaped effects on the employment–residential ratio, with inflection points at Node = 0.330, Place = 0.412, and TODness = 0.776, identifying the critical transition from balance to employment polarization. (2) Number of subway directions is the most critical indicator, together with betweenness centrality, floor area ratio, population size, and land use entropy, each exhibiting notable threshold effects. (3) A significant interaction effect exists between betweenness centrality and land use entropy, suggesting that traffic network connectivity and land use evenness can jointly regulate the employment–residential ratio in both directions. This study provides a quantitative basis for phased regulation of jobs–housing relationships in high-density TOD station areas, with findings transferable to other high-density cities. Full article

Background: A Phase I trial to study the efficacy and safety of MR-guided FUS-MB (focused ultrasound–microbubble) treatment combined with radiotherapy (RT) using a fully electronically MRI-guided steerable focused ultrasound system was performed. The investigation here carried out an exploratory quantitative analysis of images for the first ten participants who were treated with MRgFUS-MB therapy, identifying texture-based MRI features that changed significantly after treatment and indicating probable treatment-related changes in tumour morphology. Methods and Findings: Ten patients with stage I-IV breast cancer (Age: 64 ± 10.8) underwent 2 FUS-MB therapies throughout their radiation treatments, as deemed appropriate by a multidisciplinary team. MRI scans were performed prior to treatment and at 1- and 3-month follow-up. The tumours were segmented, and 2D and 3D features, including shape, first-order and texture features, were extracted for original and wavelet-filtered T1-weighted fat-saturated MR images. The overall significance of radiomic features in association with morphological changes in the target tumour over 1-month and 3-month follow-up in comparison to the first treatment day was investigated. Results: The five most significant features (p < 0.05) were selected using a sample-related t-test, out of which most features were wavelet-filtered first-order features. First-order wavelet-filtered robust mean absolute deviation (RMAD) emerged as the most consistent significant feature for both 2D and 3D features with sampled grid spacings of 0.5 mm and 1 mm. The volume of the tumour demonstrated a decline for 80% of patients over 3 months, as measured by the 3D mesh volume of the tumour ROI. There was a significant decline in tumour size and image heterogeneity, indicating plausible changes in the tumour microenvironment possibly related to the treatment. Conclusions: Previous preclinical studies and clinical evaluations have demonstrated the efficacy of MR-guided FUS-MB therapy. MRI image-based features from the T1-weighted MR scans over various follow-up times provide potential evidence of changes in tumour tissue heterogeneity that might be treatment-related. MRgFUS MB therapy can possibly evolve as a mode of radiotherapy enhancement in the future, which warrants further controlled validation. The availability of adequate data in the future might possibly lead to the identification of image biomarkers related to treatment response, thus providing better clinical evaluations. Full article

Temperature- and strain-rate-dependent serrated flow, localized plastic instability, and qualitative microcrack evolution in Mn13 Hadfield steel were investigated using stress–strain analysis and in situ tensile observation. Solution treatment at 1050 °C for 1–1.5 h followed by water quenching yielded homogeneous single-phase austenite. Type A and Type B serrations were dominant at room temperature at 1 × 10⁻³ s⁻¹ and at 100 °C at 1 × 10⁻² s⁻¹, whereas the room-temperature specimen tested at 1 × 10⁻² s⁻¹ showed delayed serration onset and pronounced Type B stress drops only at high strains. Type C serrations occurred mainly near fracture at 100 °C at 1 × 10⁻³ s⁻¹, 200 °C at 1 × 10⁻² s⁻¹ and 200 °C at 5 × 10⁻² s⁻¹. In situ observations further reveal that different serration types correspond to distinct localized deformation modes. During Type A serrations, the tracked feature exhibited unidirectional stepwise migration involving forward motion, arrest, and renewed advance. Type B serrations were associated with discontinuous pulse-like migration characterized by rapid forward motion, brief arrest, local backward motion, and renewed advance. No regular trajectory was observed during Type C stress drops; only local brightness changes and slight positional shifts occurred. These observations link macroscopic serrations to localized deformation in Mn13 steel and provide qualitative in situ evidence for grain-boundary microcrack initiation and evolution during deformation. Full article

Channel fading and impulse noise in low-voltage station areas severely hinder data acquisition, and effective estimation of dual-mode channel data and state is the critical prerequisite for adaptive transmission. To address the impact of impulse noise on the performance of Orthogonal Frequency Division Multiplexing (OFDM) power line communication systems, this paper proposes a wireless-assisted joint estimation algorithm of channel fading and impulse noise in dual-mode OFDM systems. Firstly, a model of the dual-mode OFDM system combining power line and wireless links is established, and the initial channel estimation is obtained based on Linear Minimum Mean Square Error (LMMSE), the wireless link is used as an aid to provide a relatively reliable initial symbol estimation for the power line link. Then, a two-stage approach for initial impulse noise estimation is proposed: firstly, the possible impulse noise is located based on constructed residuals to form a support set, followed by refinement of the impulse amplitude using Single Measurement Vector Sparse Bayesian Learning (SMV-SBL). Finally, a decision-feedback iterative update is performed to iteratively optimize the symbol detection, channel estimation, and impulse noise estimation processes. Combined with adaptive dual-mode fusion, this approach improves estimation accuracy. Simulation results demonstrate that the proposed algorithm achieves significant improvements in estimation accuracy and bit error rate. Full article

Crinum amoenum Roxb. ex Ker Gawl. (C. amoenum) is traditionally used in Nepal, but its antidiabetic potential remains insufficiently validated. This study characterized the 80% (v/v) ethanol bulb extract of C. amoenum and evaluated its antioxidant, α-amylase inhibitory, hypoglycemic, molecular docking, molecular dynamics (MD) simulation, and ADMET profiles. The ethanolic bulb extract was evaluated through phytochemical screening, thin-layer chromatography, total phenolic content (TPC), total flavonoid content (TFC) estimation, LC-MS analysis, antioxidant assays, α-amylase inhibition assays, acute toxicity testing, and hypoglycemic/oral glucose tolerance test (OGTT) studies in Wistar rats. Lycorine, pratorinine, and palmatine were docked against α-amylase (PDB ID: 5U3A) and GLP-1R (PDB ID: 6GB1), followed by 200 ns MD simulations and ADMET prediction. Qualitative analysis of the extract was positive for flavonoids, phenolic compounds, tannins, saponins, alkaloids, and carbohydrates, and a positive Salkowski reaction indicated the presence of constituents occurring in glycosidic form. The TPC was 173.38 ± 1.22 mg GAE/g, and the TFC was 314.58 ± 0.09 mg QE/g. LC-MS tentatively annotated lycorine, pratorinine, and palmatine based on retention time, m/z values in positive-mode electrospray ionization, and comparison with previously reported spectral information. The extract showed DPPH scavenging activity (IC₅₀: 90.98 μg/mL) and strong α-amylase inhibition (IC₅₀: 49.31 μg/mL) compared with acarbose (IC₅₀: 51.51 μg/mL). No deaths were observed following oral administration at 5000 mg/kg to rats. The 500 mg/kg dose produced the greatest hypoglycemic response, reducing blood glucose by 35.78% at 120 min in non-diabetic Wistar rats and by 19.21% at 60 min in glucose-loaded rats. Among all the compounds tested, pratorinine demonstrated the highest docking affinity with α-amylase (−8.2 kcal/mol; ASP300) and GLP-1R (−7.0 kcal/mol; GLY132). MD simulation supported greater stability of the α-amylase complex, and ADMET prediction identified pratorinine as a comparatively favorable predicted lead candidate (LD₅₀: 1000 mg/kg; Class 4 toxicity category). Pratorinine was identified as the most promising in silico antidiabetic candidate from the C. amoenum extract, primarily due to stable α-amylase interactions and favorable ADMET properties. Full article

Few-mode fiber (FMF) grating sensing exploits the mode-dependent responses of multiple spatial modes to external perturbations, enabling vector and dual-parameter measurements. This paper reviews the research progress of FMF grating sensors from the perspectives of fundamental mechanisms, fabrication techniques, signal demodulation, and representative sensing applications. First, the mode propagation characteristics, coupled mode theory, and phase matching conditions of FMF gratings are discussed. Then, the fabrication strategies of FMF gratings are summarized, followed by an analysis of signal demodulation methods. Particular attention is given to vector sensing and dual-parameter sensing. Finally, the remaining challenges related to mode excitation stability, spectral resonance overlap, fabrication repeatability, packaging reliability, and long-term calibration are discussed, and future opportunities in mode engineering, multidimensional demodulation, and intelligent sensing systems are outlined. Full article

Grid-following (GFL) renewable energy stations may experience phase-locked loop (PLL)-dominated small-disturbance synchronization instability in weak grids, while grid-forming (GFM) devices can improve the damping of this mode. However, most current studies directly approximate GFM as an ideal voltage source without providing rigorous proof. There is also a lack of in-depth analysis on how the parameters of GFM affect its enhancement effect on the small disturbance synchronization stability of GFL. To address this gap, this paper establishes an ordinary differential equation model of the GFL/GFM hybrid system and proposes a fourth-order polynomial approximate root method suitable for polynomials with two pairs of weakly damped conjugate complex roots. Based on this method, the approximated form of the PLL damping is given, and the effect of the inertia time constant, damping coefficient, and capacity of a virtual synchronous generator (VSG) on the PLL mode damping was analyzed analytically. Moreover, it was proven that VSG with a certain level of inertia can play a role close to the ideal voltage source in improving the small disturbance synchronization stability of GFL. Finally, an electromagnetic transient simulation model was established on MATLAB/Simulink, and these conclusions were verified. Full article

Percolation-based dry anaerobic digestion (AD) is an attractive technology for treating high-solids food waste (FW) because it requires minimal water addition and eliminates the need for mechanical mixing. However, its methane production is often limited by slow hydrolysis and inefficient conversion of soluble intermediates. To overcome these limitations, this study developed a bioelectrochemical leach-bed reactor (BLBR) by integrating a microbial electrolysis cell with a percolation-based dry AD system to enhance methane production kinetics. Two 10-L reactors were operated in 10-day batch mode: an open-circuit control reactor and a bioelectrochemical reactor operated with applied voltages ranging from 0.3 to 1.2 V. Moderate voltage application significantly enhanced methane production, with the highest cumulative methane yield reaching 293 mL CH₄/gVS_added at 0.9 V, representing a 47% increase over the control (199 mL CH₄/gVS_added), while volatile solids removal remained comparable between treatments. Voltage-assisted operation promoted a rapid increase in soluble chemical oxygen demand (SCOD), followed by faster consumption than in the control. Similarly, acetate and propionate accumulated and were depleted earlier, indicating accelerated conversion of soluble intermediates. A transient butyrate concentration of 8.8 g COD/L was observed at 0.9 V, suggesting enhanced fermentative activity under moderate bioelectrochemical stimulation. Full article

Background: Right-to-left shunting through a patent foramen ovale (PFO) is an underrecognized yet potentially reversible cause of refractory hypoxemia, particularly in patients with right ventricular dysfunction. This case report describes heart-rate-dependent right-to-left shunting through a PFO causing refractory hypoxemia in a patient with inflammatory cardiomyopathy and severe right ventricular dysfunction, presumably arising from biventricular output mismatch. Case Presentation: We report the case of a 41-year-old male with inflammatory cardiomyopathy and a recently implanted single-chamber pacemaker (VVI mode, lower rate limit 50 bpm), admitted for decompensated heart failure. After initial clinical improvement with guideline-directed therapy, the patient’s intrinsic heart rate declined, and ventricular pacing at 50 bpm became the dominant rhythm. He subsequently developed refractory hypoxemia unresponsive to mechanical ventilation. Systematic hemodynamic assessment was performed using transthoracic echocardiography and thoracic electrical bioimpedance (TEB) monitoring at different pacing rates. Results: Echocardiographic evaluation revealed dynamic interatrial shunting through a PFO with the following characteristics: left-to-right at a pacing rate of 80 bpm and right-to-left at 50 bpm. Hemodynamic and echocardiographic data suggested that bradycardia induced biventricular output mismatch—left ventricular outflow tract velocity–time integral (VTI) increased by approximately 38% (from 17.5 cm to 24.1 cm), whereas right ventricular outflow tract VTI increased by only approximately 4% (13.3 cm vs. 13.8 cm). This mismatch likely resulted in relative elevation of right atrial pressure, thereby driving right-to-left shunting through the PFO. Increasing the pacing rate to 80 bpm reversed the shunt direction, normalized oxygenation, and facilitated successful extubation. Conclusions: This case suggests that in patients with severe right ventricular dysfunction, bradycardia may induce biventricular output mismatch with substantially greater left than right ventricular stroke volume augmentation, and presumably relative elevation of right atrial pressure, potentially leading to dynamic right-to-left shunting through a PFO. For such patients with unexplained hypoxemia, the possibility of dynamic PFO shunting should be considered. Appropriately increasing the pacing rate may help restore biventricular output matching, reverse shunt direction, and improve oxygenation; individualized heart rate management strategies warrant clinical consideration. Full article

Advanced High-Strength Steel (AHSS) exhibits stress-state-dependent competing shear–tensile fracture modes that limit the applicability of conventional ductile fracture criteria based solely on equivalent plastic strain accumulation, such as the Forming Limit Diagram (FLD) approach and the classical Gurson–Tvergaard–Needleman (GTN) model. This paper proposes an extended GTN damage model incorporating Hill’48 anisotropy and the Nahshon–Hutchinson shear mechanism, regulated by a stress-state-dependent weighting function. The experimental program comprised uniaxial tension tests for constitutive calibration, notched plate specimens with shear angles ranging from 0° to 90° (spanning pure shear to tensile–shear stress states), and tension-bending tests. The fracture initiation point was identified from the abrupt load drop on the experimental force–displacement curve and further located in the finite element simulation to extract the corresponding stress-state history. SEM fractography was employed to characterize the microscopic damage mechanisms, revealing a continuous transition from shear-dominated to void-dominated damage at a critical stress triaxiality of approximately 0.35. A weighting function dependent on both stress triaxiality and the normalized Lode angle was formulated to couple void evolution with shear band localization. Following calibration via finite element inverse fitting, the model, implemented as an ABAQUS VUMAT subroutine, successfully reproduced fracture strains and crack paths across stress states ranging from pure shear to high hydrostatic tension. Comparative simulations indicate that this approach yields improved prediction accuracy over the classical GTN model, particularly under mixed-mode conditions, thereby offering a practical numerical tool for analyzing AHSS formability. Full article

This work aims to explore the gravitational consequences of a recently proposed black hole solution previously introduced, which incorporates quantum gravitational corrections of General Relativity. We initiate our analyses by taking into account the horizon structure, focusing on both the event and Cauchy horizons. Subsequently, we examine the quasinormal modes by considering all types of perturbations—scalar, vector, tensor, and spinorial. To strengthen these results, we also compute the time domain for each perturbation. Next, we turn to the study of optical properties of the black hole. In particular, we investigate null geodesics, the photon sphere and its stability, and the corresponding black hole shadows. Following this, we analyze gravitational lensing phenomena in two regimes: the weak-field limit, utilizing the Gauss–Bonnet theorem, and the strong deflection limit, employing Tsukamoto’s approach. In addition, we address the lensing observables with Event Horizon Telescope (EHT) data for $SgrA*$ and $M87*$. Finally, constraints on the parameter $\xi$—which is introduced by higher-order curvature–scalar gravity, thereby differing from the Schwarzschild solution—are estimated using Solar System measurements such as the precession of Mercury’s orbit, gravitational light bending, and time delay (or the Shapiro effect). Full article

This study investigates the efficiency of green corrosion inhibitors derived from spent coffee grounds (SCGs) for OL 37 carbon steel in 0.5 M H₂SO₄ and 1 M HCl environments. The aqueous extracts, labeled K1 and K2, were obtained through specialized extraction techniques and characterized by HPLC. Their protective performance was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). FT-IR spectroscopy and SEM-EDX analysis confirmed the presence of a protective inhibitor film on the OL 37 surface, attributed to the adsorption of organic molecules from the SCGs extract (K1 and K2). The adsorption behavior followed the Langmuir isotherm, with high adsorption constants and standard free energy values (ΔG°_ads), indicating a mixed-mode adsorption mechanism. Furthermore, the negative Gibbs free energy values of adsorption confirm the spontaneity of the adsorption process. Thermodynamic studies conducted between 293 K and 333 K demonstrated the temperature dependence of the inhibition process. Results showed that at a concentration of 800 ppm and 1000 ppm, both inhibitors exhibited high efficiency, reaching 96% for K1 and 95% for K2. Full article

This study presents a full-voyage operational validation of a load optimization strategy applied to a Dual-Fuel Diesel-Electric (DFDE) liquefied natural gas (LNG) propulsion system. The proposed approach was evaluated onboard an LNG carrier equipped with five four-stroke dual-fuel engines. The operational validation was conducted exclusively with the generator engines operating in LNG (gas) mode, while operation on conventional liquid fuels was outside the scope of this study. A complete 26-day voyage cycle, including cargo loading, loaded passage, cargo discharge, and ballast passage, was defined. Representative steady-state operating intervals for each operational mode were analyzed under both conventional Power Management System (PMS) load distribution and optimized load allocation. Real-time manual redistribution of engine loads was performed to validate the proposed load optimization strategy under real operating conditions. The results show consistent fuel savings across all operating modes, with the highest reduction observed during ballast passage (1.51%), followed by loaded passage (0.74%). A voyage-scale analysis reveals cumulative fuel savings exceeding 22 metric tons per operational cycle, equivalent to annual reductions of more than 300 metric tons under typical service conditions. These savings consistently reduce both carbon dioxide (CO₂) and nitrogen oxides (NO_x) emissions across all operating modes. Ultimately, the proposed load optimization strategy demonstrated stable performance under the investigated steady-state operating conditions and provides a practical approach to improving ship energy efficiency. The results support the potential application of the proposed strategy in existing ship energy management systems, while further validation under long-term and transient operating conditions is recommended. Full article

Unmanned Aerial Vehicle (UAV)-borne laser wavefront sensing technology holds significant application prospects for high-precision vibration detection in the field; however, the acquired signals are highly susceptible to complex, nonlinear environmental noise interference. Existing high-precision deep learning denoising models typically rely on massive computational resources, making them difficult to deploy on resource-constrained edge devices. Consequently, practical engineering exploration is often confined to an inefficient “blind sampling followed by offline processing” mode, incurring a high risk of data invalidation. To explore solutions for real-time quality control at the edge, this paper proposes a lightweight time-frequency state space model (SWIFT-Mamba), aiming to provide an efficient algorithmic foundation and an engineering proof-of-concept for portable devices moving toward in situ verification. Through rigorous evaluation on over 60,000 laboratory-measured and controlled synthetic wavefront vibration data samples, SWIFT-Mamba achieves an average Signal-to-Noise Ratio (SNR) gain of 19.64 dB and a Scale-Invariant Signal-to-Distortion Ratio (SI-SDR) gain of 16.10 dB, with an extremely low computational overhead requiring only 0.066 M parameters and 0.147 GFLOPs. Experimental results demonstrate that while significantly reducing computational costs, the proposed model can effectively extract the physical manifold of the signal and precisely preserve high-frequency phase features. Full article