Search Results (1,062)

A^IVB^VI semiconductors, particularly lead chalcogenides, remain key materials for mid-wave infrared (MWIR) photodetection due to their narrow bandgap and exceptional carrier transport properties. However, the realization of high-quality p-type PbTe thin films, suitable for p–n junction devices, remains a technological challenge. In this work, we report the fabrication of high-mobility p-type PbTe thin films grown on muscovite mica by electron beam-assisted physical vapor deposition. The films were derived from a Te-rich Pb_0.999Te_1.001 ingot, enabling controlled acceptor formation via excess tellurium. Structural characterization reveals growth with strong (111) texture, large grain size, and low surface roughness. Comprehensive electrical measurements in the range of 80–300 K show a record room-temperature hole mobility of 876 cm²/V·s, achieved under optimized fabrication conditions. This figure approaches values typical for epitaxial n-type PbTe, indicating low scattering and high crystallinity. These results establish an effective route for producing strongly (111)-textured p-type PbTe films with high room-temperature hole mobility through optimized deposition and post-deposition annealing. Full article

Light limitation can constrain primary production and ecosystem recovery in shallow eutrophic lakes even when nutrients remain abundant. We evaluated the effects of reduced physical disturbance on underwater light availability in Utah Lake, Utah, USA, using large limnocorrals that reduced exposure to wave-driven disturbance and restricted access by benthivorous fishes. Water transparency was assessed using Secchi depth during 2022–2023 and vertical profiles of photosynthetically active radiation (PAR) during 2024; the two datasets were analyzed independently. The mean Secchi depth was approximately 81% greater inside than outside the limnocorrals (39.8 vs. 22.0 cm; p < 0.001). Similarly, PAR declined to a theoretical photosynthetic threshold of 0.01 µmol photons m⁻² s⁻¹ at an estimated depth of 101 cm inside the corrals compared with 81 cm outside the corrals, representing a 25% increase in potential photosynthetic depth. Phytoplankton biovolume was not a detectable predictor of Secchi depth after accounting for treatment and month (p = 0.996), although chlorophyll a and phycocyanin were associated with PAR at shallow depths and phytoplankton became more important during late-season bloom conditions. Total suspended solids (TSSs) were associated with PAR throughout the measured depth profile but differed only slightly between treatments (72.89 vs. 75.16 mg L⁻¹; p = 0.08). Thus, the large optical response cannot be explained by changes in bulk TSS concentration alone and may instead reflect changes in the optically active suspended-particle fraction, including preferential settling of fine, strongly scattering particles; particle-size distributions and optical properties were not directly measured. These results demonstrate that reducing physical disturbance can substantially improve underwater light conditions in a large, shallow, nutrient-rich lake. Management approaches that reduce sediment resuspension and restore benthic light availability may therefore provide a direct pathway toward ecosystem reorganization, particularly where large internal nutrient stores and atmospheric inputs limit the effectiveness of external nutrient reductions alone. Full article

An atmosphere–ocean–wave-coupled model, the UWIN-CM, running in real-time in the Hong Kong Observatory, has adopted radar data assimilation (DA) and been incorporated with a HAILCAST module in WRF for hail size simulation. This paper analyzes the distribution of maximum hail sizes forecast by the UWIN-CM in comparison with the Maximum Estimated Size of Hail (MESH) from radar for six hail cases reported by human or derived from radar in the Pearl River Estuary of Guangdong Province in 2026. The performance of hail forecast with and without radar DA is compared. The model with DA performed simulates hail at the locations that were consistent with the reported data and/or MESHs in five out of six cases. The timings of simulated hail aligned with reports/MESHs in three cases, and these were delayed by approximately 1 to 3 h in the remaining two. For the average hail diameters, those from simulations were smaller than MESH by around 30 to 50% in two of the five successful cases, while the other three cases had larger diameters than MESH by about 90 to 140%. Without radar DA, hails were simulated in only two out of six cases. The rate of detection was enhanced with radar DA, potentially benefiting from the improved moisture distribution and wind field of the initial conditions. The possible factors behind the differences in hail size between the simulations and MESH are discussed, including the choice of microphysics scheme and the differences in climatology between the PRE, and the contiguous US where the HAILCAST parameters were calibrated. For practical use in operation, parameter tuning of HAILCAST based on the hail climatology of the PRE would be needed. This work paves the way for providing forecasters with early alerts about the occurrence of hail in the region. Full article

This study presents the first evaluation of the degree of nonlinearity in site response at strong-motion stations in Türkiye during the 6 February 2023 Kahramanmaraş earthquake sequence (Mw 7.8 and Mw 7.5) using earthquake horizontal-to-vertical spectral ratios (eHVSRs). The analysis uses 2050 weak-motion and 175 strong-motion records from 24 AFAD stations in the Kahramanmaraş and Hatay regions, where some of the strongest ground motions and most severe damage were observed. The selected stations cover a broad range of site conditions, from soft alluvial deposits to relatively stiff sites, as characterized by Vs30. Conventional assessments of nonlinear site response generally rely on peak ground-motion measures and one-dimensional site proxies, particularly Vs30. In contrast, this study evaluates nonlinear behavior within a record-based framework that accounts for the combined influence of source characteristics, propagation path, local site conditions, and basin-related wave effects. Nonlinear site response is quantified by comparing strong-motion and weak-motion eHVSR spectra, where the weak-motion reference is derived from records with peak ground velocity (PGV) lower than 1 cm/s. A principal methodological contribution is the use of record-specific S-wave windows selected according to the event-dependent energy content of each record, rather than a uniform fixed-duration window. This energy-based procedure focuses on the dominant S-wave energy while reducing pre-event noise and late-arriving coda effects. Incorporating record-specific S-wave duration improves degree of nonlinearity (DNL) estimates, proving that nonlinear response is driven not just by peak amplitude and near-surface stiffness but also by duration-dependent cyclic deformation demand. The proposed framework provides record-based constraints for empirical ground-motion models and regional three-dimensional physics-based earthquake simulations. Full article

Background/Objectives: The aim of the study was to compare the effectiveness of SWE in AUS-nuclear and AUS-other nodules, including nodules with an unequivocal cytology (UC), taking into account the size of the nodules. Methods: We evaluated 100 AUS-nuclear and 131 AUS-other nodules with known results of EU-TIRADS, repeat FNA (rFNA), and histopathological examination, and 92 nodules with UC: 47 malignant and 45 benign. Two SWE measures were used: Ewhole—capturing the largest possible area of the nodule; and Estiffest—limited to its hardest part. Results: In the UC group, values of both SWE measures above the thresholds were a significant malignancy risk feature regardless of the nodule size, but only Estiffest in nodules > 1 cm was an independent malignancy risk feature. In both AUS subcategories, similar results were obtained only for nodules > 1 cm; but, even in this group, rFNA and EU-TIRADS had a higher accuracy than SWE in the differentiation of benign and malignant nodules, and no SWE measures were an independent malignancy risk feature. However, in the AUS-nuclear subcategory, where PTC predominates among cancers, adding Estiffest to the EU-TIRADS and rFNA assessment led to some increase in sensitivity with an acceptable decrease in specificity. In the AUS-other subcategory, where the profile of cancers is more diverse, a similar effect was obtained by the addition of Ewhole. Conclusions: SWE may complement rFNA and TIRADS in category III nodules > 1 cm, but the decision whether to apply SWE and which measures should be used depends on the pre-test probability of cancer and the expected frequency of PTC among cancers. Full article

Reverse osmosis (RO) desalination is a major technology for freshwater production in arid regions, but its energy demand becomes more challenging when the system is supplied by variable renewable energy. This study presents an offline digital-twin-assisted decision-support framework for dynamic RO under Kuwait solar-availability conditions. Within this framework, the predictive models are driven primarily by the dynamic RO process variables, while NASA Prediction Of Worldwide Energy Resources (POWER) data provide the Kuwait solar-availability context, and the PV power margin serves as a scenario-level energy indicator. The purpose is to predict instantaneous permeate flow rate, estimate specific energy consumption, and identify energy-efficient operating conditions using machine learning. Kuwait City was used as the solar case-study location. Hourly solar and meteorological data were obtained from NASA POWER, while dynamic RO membrane data were obtained from the open experimental wave desalination dataset published by the National Renewable Energy Laboratory (NREL) through Data.gov and the Marine and Hydrokinetic Data Repository. The RO dataset includes steady-state, ramp, sinusoidal, and Wave Energy Converter SIMulator (WEC-Sim) pressure/flow experiments. The process-flow image used in the system description was also taken from the same NREL dataset and is cited in the figure caption. The raw RO files were cleaned, harmonized, and transformed into a process-informed modeling dataset. Derived features included pressure rate, recovery ratio, salt rejection, estimated pump power, specific energy consumption (SEC), PV power margin, and rolling pressure/flow features. Three supervised regression models were tested: Gradient Boosting, Random Forest, and XGBoost. A representative subset of 60,000 records was used to preserve the main experimental conditions while reducing redundancy in the densely sampled sequential data. Results show that permeate flow rate can be predicted with high accuracy using Gradient Boosting (R² = 0.981; RMSE = 0.161 L/min). The moderate energy prediction performance yielded an R² of 0.654 and RMSE of 7.570 kWh/m³ for Random Forest. The accuracy of permeate conductivity predictions was lower (R² = 0.257; RMSE = 245.44 µS/cm) because membrane and feed characterizing parameters should be included for an adequate water quality control. The proposed approach is best suited as an offline decision-support framework for dynamic RO process analysis. Full article

This work presents the first complete system for automated six degrees of freedom (6DOF) satellite pose estimation from spatially resolved, ground-based, adaptive optics (AO)-corrected imagery, addressing a key challenge in Space Domain Awareness (SDA). The approach mitigates the need for human labeling by directly regressing satellite orientation and position from blurry, noisy, and deeply shadowed imagery. A multi-stage deep neural network pipeline localizes the satellite, predicts pose, and optionally applies temporal filtering. Networks are trained exclusively on fully synthetic imagery generated from a CAD model, yet generalize effectively to real data, bridging the Sim2Real domain gap. On 137 real, human-labeled test images of Seasat, the model achieved a mean rotation error of $5^{°}$ and a mean image-plane translation error of 21 cm. Slant range error was quantitatively evaluated on synthetic data due to unknown real-sensor parameters. Qualitative evaluation of additional real Seasat imagery rated 177 of 199 predicted poses as “ground truth equivalent” or “high-confidence match,” with zero catastrophic failures. The system was extended to seven degrees of freedom (7DOF) for satellites with articulating components and demonstrated on real Hubble Space Telescope (HST) imagery, achieving ${5.5}^{°}$ rotation error, 51 cm image-plane translation error, and $8^{°}$ symmetry-adjusted solar array error on a 249-frame pass with causal temporal filtering. Across 586 real test images from Seasat and HST (captured over multiple decades under diverse conditions) the system consistently performed well. Full 6DOF performance was quantified on a high-fidelity wave optics (HFWO) synthetic test set of Seasat, where the model achieved ${8.4}^{°}$ mean rotation error, 34 cm image-plane translation error, and 1.4% line-of-sight range error at $r_0=6$ cm and 1031 km range. In a limited 200-image benchmark, the model demonstrated 48% lower mean rotation error than a single human labeler while operating ∼800× faster. It required <40 h and a single A100 GPU to generate data and train. The approach was also demonstrated for ARGOS, a smaller satellite with highly symmetric geometry. An exploratory General Image-Quality Equation-based image quality metric (AO-IQ) was introduced as an empirical correlate for pose accuracy. General-purpose models like GPT-4o and Depth Anything V2 failed across most SDA tasks, but rapid gains in vision-language models warrant continued monitoring. These results establish a new operational baseline for practical, real-time satellite pose estimation from AO SDA imagery. Full article

This study demonstrates that supercritical carbon dioxide phase-change fracturing technology can reduce acute pressure-related injury potential compared to conventional explosives in underwater reef clearance operations along the Yangtze River. Employing a stepwise “pipe test, numerical simulation and engineering application” framework, a novel rock–water–fish coupled HJC–Gruneisen elastoplastic model was established to simulate cross-medium shock wave attenuation processes. The supercritical CO₂ shock wave exhibits characteristics of “low peak overpressure (13% of equivalent explosives) and long duration (6–7 times longer than conventional explosives),” attenuating in water with a power-law index α = 0.717. A dual-parameter “resistance line (intact rock buffer between the fracturing tube and the rock–water interface)–water depth” correction model indicates that the resistance line reduces peak overpressure by 18.6%, while each 10 m increase in water depth enhances attenuation by 60.6%. The preliminary engineering critical safety threshold for 30 cm silver carp (indicated by swim bladder rupture) is 0.20 MPa. Based on the representative engineering scale of the Chaofu Waterway Regulation Project, characterized by water depths of approximately 6–16 m and a resistance-line-controlled buffer condition, a theoretical safety distance model R_safe was also derived. Under these engineering constraints, the application results indicate that the lethal zone was confined to 7.5–9.9 m, enabling precise lethal-injury-safe zoning. This work establishes a fish injury threshold and safety assessment system for supercritical CO₂ subaquatic fracturing, providing direct green guidelines for Yangtze River navigation projects. Full article

Landslide-induced surges and subsequent dam breaching constitute severe cascading hazards in mountainous gorges. Conventional steady-flow sediment theories fail to describe these extreme, unsteady processes, and existing research focuses on wave propagation rather than surge-driven erosion mechanisms. Using the Baige landslide dam as a prototype, this study combines 1:100 physical model tests with CFD-DEM simulations to investigate how landslide fall height, water depth, and sediment gradation govern surge propagation, dam scour, and sediment transport. The results show the surge amplitude reaches 38.21 cm under high-fall, deep-water conditions and decays nonlinearly. Fine-grained beds exhibit suspended-load transport (max concentration 15.2%), whereas coarse-grained beds develop scour pits via bedload transport, with deposition volume increasing ~230%. Sediment transport follows a three-stage spatial pattern: intense erosion near the dam (max depth 2.9 cm), grain-size-sorted deposition in the middle reach (max height 4.6 cm), and fine-sediment accumulation downstream. The numerical results agree well with experiments. The constructed “water depth–gradation–energy” risk assessment matrix supports refined prediction and mitigation of landslide dam-break cascading hazards. Full article

Metal–organic bimetallic frameworks of Ni–Co, having metal content of 2:1 and 1:2 molar ratios, respectively, have been synthesized via a rapid laser method with a continuous-wave Nd:YVO₄ laser (λ = 975 nm) under 88–90 °C in a DMF/H₂O solution in 70 min. The structure, porosity, and photophysical, electrochemical, and dielectric characteristics of the frameworks and their reduced graphene oxide (rGO) composites in the form of powders and UV-cured PEGMEA/PEGDA films have been investigated. Framework Ni2Co1MOF demonstrated a BET surface area equal to 88.3 m² g⁻¹ and a total pore volume of 0.022 cm³ g⁻¹, whereas framework Ni1Co2MOF exhibited a BET surface area of 52.5 m² g⁻¹ and a total pore volume of 0.016 cm³ g⁻¹. The incorporation of rGO from 1 to 10 wt.% into the framework changed the charge transport and polarization properties of the materials. The electrochemical investigations of the 10 wt.% rGO-Ni1Co2MOF composite in 0.5 M HCl demonstrated a specific capacitance of 32.3 F g⁻¹ at 10 mV s⁻¹, and it preserved 98% of the electrochemical response after 400 cycles, in comparison with 96% for the 10 wt.% rGO-Ni2Co1MOF. The electrochemical responses consisted of both diffusion-controlled ion transport and pseudocapacitance. The introduction of rGO in 1 to 10 wt.% in the polymer composite improved the conductivity and Maxwell–Wagner–Sillars interface polarization at low frequencies in the case of low rGO concentrations, whereas overly high rGO content led to aggregation and the decreased influence of the conductive phase. The main contribution of the present work is the fast sub-100 °C synthesis approach for compositionally tunable Ni-Co frameworks/rGO materials and the relationships between the metal ratio, porous structure, interfacial charge transport, and dielectric response. Full article

Two breakwaters were constructed between 1959 and 1961 by the U.S. Army Corps of Engineers to form a harbor within Half Moon Bay on the central California coast. Prior to construction, the bay had a smooth hook-shaped or spiral form with a shoreline in equilibrium with waves refracted around a resistant point. Following breakwater completion, wave energy that had previously been dissipated along the equilibrium shoreline of the bay was concentrated at the downcoast end of the breakwater against the low weak bluffs. The original very low (~8 cm/year) bluff recession rates increased rapidly to as much as 2 m/year which led to the destruction of a county road and wastewater transmission line and began to threaten a state highway and a group of homes. Bluff erosion has progressed as far as 1.4 km downcoast which has led to rock revetment placement to protect the highway and homes. Breakwater planning also underestimated the potential for waves to enter the gap between the two breakwaters, so a dogleg extension had to be constructed. This also failed to reduce wave action, which led to the construction of an additional set of breakwaters within the harbor to protect moored boats. Full article

The determination of the angle of arrival (AoA) of Ku-band microwave signals is of great significance in satellite communications, spectrum monitoring, and national defense security, which has created an urgent demand for high-precision and interference-resistant passive detection techniques. In this study, we propose a Rydberg-atom-based passive measurement method for estimating the AoA of Ku-band incident signals. Based on well-established quantum optical techniques, the proposed method converts the EIT-AT splitting intervals induced by waves or signals incident from different directions in Rydberg atoms within a single vapor cell into the electric-field intensity at the atomic sensor. An electric-field-intensity–angle response model is then established for AoA estimation of a 13.6 GHz wave or signal. Simulation results demonstrate that the proposed method can determine the incident direction within a certain angular range, with an estimation error of less than 3.8°. Without the need for self-calibration and free from interference caused by actively emitted probing electromagnetic waves or reference electric fields, the proposed approach enables AoA determination of incident waves or signals using a single vapor cell with a length of 5 cm. Full article

A convolutional neural network (CNN) surrogate model (SM)-assisted proximal policy optimization (PPO) inverse design methodology is proposed for pixelated differential bandpass filters (DBPFs). A dumbbell-shaped defected ground structure (DGS) is encoded as a symmetric binary-pixel matrix, in which only one quarter of the pixelated encoding region is independently optimized to reduce the complexity of the design space, and the complete structure is reconstructed through mirroring. Mixed-mode S-parameters are used to jointly optimize differential-mode (DM) matching and common-mode (CM) noise suppression. A single-frequency-point surrogate model (SF-SM) predicts the complex responses and is embedded into PPO for rapid candidate evaluation, reducing repeated full-wave electromagnetic (EM) simulations. The optimized first-order unit is cascaded into a third-order DBPF. The simulated and measured results show good agreement and validate the feasibility of the proposed inverse design methodology for DBPF applications. Full article

Adaptive restraint systems require specific occupant information, including head position, anthropometry, and safety-relevant posture states. Existing 3D human pose estimation benchmarks mostly report root-relative pose, while automotive in-cabin studies rarely evaluate these outputs across heterogeneous vehicle sensor sets. We present ICF-Fusion, a five-modality transformer fusion architecture, and evaluate it under leave-one-subject-out (LOSO) validation on the ICF-Body dataset, which includes synchronized near-infrared (NIR) camera, 60 GHz millimeter-wave (mmWave) radar, belt webbing extraction sensor (WES), seat configuration sensor (SCS), and ultra-wideband (UWB) recordings. The model localizes the head with a Mean Root Position Error (MRPE) of 6.10 cm and regresses anthropometry to mean absolute errors (MAE) of 5.36 cm for height, 3.50 cm for torso length, 1.78 cm for shoulder width, and 8.61 kg for weight. Feet-on-dashboard is detected on 9 of 10 evaluable folds without meaningful MRPE degradation. The full sensor fusion outperformed every single modality on all three tasks, but NIR alone nearly matched it for head localization and feet-on-dashboard detection. The fusion advantage was substantial only for the anthropometry estimation task. Full article

Capturing reliable hyperspectral imager data at a meaningful frame rate for explosions and other fast-changing scenes is not possible in the mid-wave infrared region under traditional sensor operating configurations and processing techniques, which typically have frame rates on the order of 0.5–2.0 Hz. To combat these shortcomings, the scene acquisition parameters were tailored for explosions and a new method for processing optical signatures of fast transient scenes with Fourier-transform infrared hyperspectral imagers was developed. For this technique, the instrument was first configured to collect asymmetric interferograms while optimizing the number of measurement points on the short side of the interferogram. Additionally, pixel-wise zero path distance offset and phase corrections were applied to the interferograms, a reduced spectral resolution of 8 cm⁻¹ was selected, and the window size was narrowed to 32 × 64 pixels while using a lens with a wide field of view. The smooth offset correction for scene change artifacts was then applied in post-processing to address any remaining artifacts in the Fourier-transformed spectra. These procedures yielded a 29× increase in frame rate and significant improvements in spectra fidelity. This work makes reliable field calibrations and measurements of explosions with Fourier-transform infrared hyperspectral imagers more achievable than before. Full article