Search Results (4,792)

The Dvorak technique has represented a fundamental tool for understanding the power of tropical cyclones based on their shape and geometric evolution. However, it should be noted that the Dvorak technique is purely morphological in nature and was developed for wind, not precipitation. The role of shape methods in precipitation prediction remains uncertain, particularly in the context of modern multi-sensor capabilities. This uncertainty forms the motivation for the present study. In an attempt to enrich Dvorak’s technique, this study proposes a novel hypothesis. This study tests the hypothesis that higher precipitation intensity is associated with more organized cloud-system morphology, as captured by simple geometric descriptors and indicative of dynamically coherent convection. A total of 3419 cloud-system objects (after size filter) were utilized to establish geometric relationships in each of them. For the case study of Hurricane Patricia over the Mexican coast in 2015, 3858 geometric shapes were processed. The cloud-system morphology was derived from geostationary imagery (GOES-13) and collocated with satellite precipitation estimates in order to isolate intense-rainfall objects (>50 mm/h). For each object, simple geometric descriptors were computed, and shape variability was summarised via Principal Component Analysis (PCA). The present study sought to evaluate the associations with rain-rate metrics (mean, mode, maximum) using rank correlations and k-means clustering. Furthermore, sensitivity analyses were conducted on the rain threshold and minimum object size. A Shape Descriptor: ratio between perimeter and diameter was identified as a promising tool to enhance early prediction models of extreme rainfall, contributing to enhanced meteorological risk management. The study indicates that cloud shape can serve as a valuable indicator in the classification and forecasting of intense cloud systems. Full article

Background/Objectives: To evaluate the prevalence, age at diagnosis, non-invasive ventilation pressures used in management, and clinical predictors for sleep disordered breathing (SDB) in pediatric patients with muscular dystrophies (MDs). Methods: A retrospective analysis of 195 polysomnography (PSG) studies conducted over 20 years for 98 children with different MDs was performed. Diagnosis of SDB was established if a child met the diagnostic criteria for one or more of the following conditions: obstructive sleep apnea (OSA), central apnea, nocturnal hypoxemia, or nocturnal hypoventilation. Outcomes were assessed and compared between MDs. Positive and negative predictive values (PPV, NPV), sensitivity, and specificity for detecting SDB were calculated for certain clinical parameters. Results: SDB was diagnosed in 73.6% of children with MDs, including OSA in 67%, followed by nocturnal hypoxemia (15.3%), nocturnal hypoventilation (7.7%), and central apnea (6.6%). The age at diagnosis and BiPAP pressures used varied between MDs. Patients with Congenital MD had the lowest mean age and required higher pressures (p < 0.05). PPV was high for maximum inspiratory or expiratory pressures (MIP, MEP) < 40% or <60%, forced vital capacity < 50% or <80%, total lung capacity < 60%, left ventricular ejection fraction < 50%, non-ambulation, and body mass index ≥ 95% for the presence of SDB. However, NPV, sensitivity, and specificity varied. Conclusions: SDB is common in pediatric patients with MDs, with OSA being the most prevalent disorder. The age at diagnosis and required BiPAP pressures for management differ among MD groups. Certain clinical measures may help identify some patients with the disease given the high PPV. Full article

We present a combined experimental and modeling study of premixed atmospheric-pressure tetralin flames. Chemical speciation in near-stoichiometric (φ = 0.8–1.0) tetralin/O₂/Ar flames was characterized by probe-sampling molecular-beam mass spectrometry (MBMS) with soft ionization (12.3–18 eV). Total ionization cross-sections (TICSs) for heavy intermediates were computed ab initio to enable quantitative MBMS processing. Laminar burning velocities (LBVs) of tetralin/air flames were measured in a range of equivalence ratios (φ = 0.75–1.5) on a nozzle burner via the stretch-corrected total area method. This is the first reported LBV data for tetralin/air flames (maximum LBV was 47.3 ± 2 cm/s at φ = 1.1). The experimental mole fraction profiles and LBVs were interpreted using three detailed mechanisms. None of the mechanisms were able to correctly describe the LBV profile, and a number of discrepancies were observed in the mole fraction profiles. Reaction network and sensitivity analyses were performed to identify specific sub-mechanisms requiring refinement. In particular, the subchemistry of naphthalene and indene strongly affects the accuracy of model predictions, whereas the flame speciation data indicate large uncertainties in the simulated concentrations of these species. Full article

This study designs an underwater acoustic absorption metamaterial based on a multi-cavity diaphragm structure. The acoustic performance is carefully modeled and examined through simulations in COMSOL Multiphysics finite element software (v.6.1). First, a multilayer periodic unit model consisting of a main cavity and sub-cavities is constructed. A corresponding acoustic-structure coupled finite element model is established by incorporating diaphragm thickness and pre-tension parameters. The frequency domain analysis method is then employed to simulate sound wave transmission and resonance absorption within the structure, calculating the relationship between the acoustic absorption coefficient and frequency. Based on parametric sensitivity analysis, the study examines the influence of key parameters, including main cavity depth, slit width, sub-cavity depth, diaphragm thickness, and pre-tension, on acoustic absorption performance. The mechanisms by which these parameters regulate the absorption peak and bandwidth are revealed. The simulation results show that this metamaterial provides effective broadband acoustic absorption from 200 Hz up to 3000 Hz. The effective bandwidth with an absorption coefficient (α > 0.5) reaches 770 Hz, with a maximum absorption peak of 0.96 and an average absorption coefficient of 0.74, indicating excellent low-frequency underwater acoustic absorption capability. This study provides theoretical foundations and design guidelines for underwater noise control and related engineering applications. Full article

We investigate the dependence of the maximum etched track length ($L_{\max }$) on alpha-particle energy and incidence angle in LR-115 type II nuclear track detectors by combining Geant4 Monte Carlo simulations with controlled chemical etching experiments. The bulk ($V_{\mathrm{B}}$) and track ($V_{\mathrm{T}}$) etch rates were determined under standardized conditions, yielding $V_{\mathrm{B}}=(3.1\pm 0.1)$ µm/h and $V_{\mathrm{T}}=(5.98\pm 0.06)$ µm/h, which correspond to a critical detection angle of about $(58.8\pm 1.2)°$. Simulations covering initial energies spanning 1 MeV to 5 MeV and incidence angles up to $70°$ confirmed that the maximum etched track length varies quadratically with particle energy E and depends systematically on incidence angle $\theta$. Empirical parameterizations of $L_{\max }(E,\theta )$ were obtained, and energy thresholds for complete track registration within the 12 µm sensitive layer were established. The angular acceptance predicted by the $V_{\mathrm{T}}/V_{\mathrm{B}}$ ratio was validated, and the results demonstrate that $L_{\max }$ provides a monotonic and more reliable observable for energy calibration compared to track diameter. These findings improve the quantitative calibration of LR-115 detectors and strengthen their use in environmental radon monitoring, radiation dosimetry, and alpha spectrometry. In addition, they highlight the utility of Geant4-based modeling for refining solid state nuclear track detector response functions and guiding the development of optimized detector protocols for nuclear and environmental physics applications. Full article

Sandflies spread the neglected vector-borne disease anthroponotic cutaneous leishmaniasis (ACL), which only affects humans. Despite decades of control, asymptomatic carriers, vector pesticide resistance, and low public awareness prevent eradication. This study proposes a fractional-order optimal control model that integrates biological and behavioral aspects of ACL transmission to better understand its complex dynamics and intervention responses. We model asymptomatic human illnesses, insecticide-resistant sandflies, and a dynamic awareness function under public health campaigns and collective behavioral memory. Four time-dependent control variables—symptomatic treatment, pesticide spraying, bed net use, and awareness promotion—are introduced under a shared budget constraint to reflect public health resource constraints. In addition, Caputo fractional derivatives incorporate memory-dependent processes and hereditary effects, allowing for epidemic and behavioral states to depend on prior infections and interventions; on the other hand, standard integer-order frameworks miss temporal smoothness, delayed responses, and persistence effects from this memory feature, which affect optimal control trajectories. Next, we determine the optimality conditions for fractional-order systems using a generalized Pontryagin’s maximum principle, then solve the state–adjoint equations numerically with an efficient forward–backward sweep approach. Simulations show that fractional (memory-based) dynamics capture behavioral inertia and cumulative public response, improving awareness and treatment efforts. Furthermore, sensitivity tests indicate that integer-order models do not predict the optimal allocation of limited resources, highlighting memory effects in epidemiological decision-making. Consequently, the proposed method provides a realistic and flexible mathematical basis for cost-effective and sustainable ACL control plans in endemic settings, revealing how memory-dependent dynamics may affect disease development and intervention efficiency. Full article

Accurate assessment of wetland hydraulic performance and solute treatment depends on the spatial resolution of bed topography and vegetation density. To evaluate this influence, synthetic shallow-water wetlands with spatially correlated random fields of bed elevation and vegetation density were used to examine how data resolution affects predictions of hydrodynamic residence time and treatment performance. Coarse-graining of input data produced modest median errors in nominal residence time, although variability across realizations increased with greater topographic heterogeneity. The variance of residence time was the most sensitive metric, showing a consistent tendency toward underestimation as grid size increased, with maximum median errors exceeding 10% and 35% for grid sizes equal to and twice the correlation length, respectively. In contrast, outlet concentration errors remained relatively small, typically below 5% even when grid size exceeded the correlation length of bed features, indicating a stronger dependence on nominal residence time than on variance. Within the range of vegetation stem density variability considered, heterogeneous vegetation patterns in a flat-bed wetland exerted comparatively little influence on residence time metrics and contaminant concentration at the outlet. The results provide insights into the reliability of wetland models under varying data resolutions and identify conditions under which coarse-graining is acceptable, offering guidance for field measurement strategies and numerical modeling. Full article

Undesirable water-in-crude oil emulsions in the oil and gas industry can lead to several issues, including equipment corrosion, high-pressure drops in pipelines, high pumping costs, and increased total production costs. These emulsions are commonly treated with surface-active chemicals called demulsifiers, which can break an oil–water interface and enhance phase separation. This study introduces a novel approach based on neural networks to estimate demulsification efficiency and to aid in the selection of demulsifiers under field conditions. The influence of various types of demulsifiers, demulsifier concentration, time required for demulsification, temperature and asphaltene content on the demulsification efficiency is analyzed. To improve model accuracy, a modified full-scale factorial design of experiments and the comparison of response surface method with multilayer perception neural networks were conducted. The results demonstrated the advantages of using neural networks over the response surface methodology such as a reduced settling time in separators, an improved crude oil dehydration and processing capacity, and a lower consumption of energy and utilities. The findings may enhance processing conditions and identify regions of higher demulsification efficiency. The neural network approach provided a more accurate prediction of maximum of demulsification efficiency compared to the response surface methodology. The automated multilayer perceptron neural network, with an architecture consisting of 3 input layers, 14 hidden layers, and 1 output layer, demonstrated the highest validation performance R² of 0.991932 by utilizing a logistic output activation function and a hyperbolic tangent activation function for the hidden layers. The identification of shifted optimal values of time required from demulsification, demulsifier concentration, and asphaltene content along with sensitivity analysis confirmed advantages of automated neural networks over conventional methods. Full article

Dynamical downscaling is an essential approach for bridging the gap between coarse-resolution global climate models and regional details required for climate impact assessment and sustainable development planning. Thailand, a climate-sensitive country in Southeast Asia, requires robust climate information to support its adaptation and resilience strategies. This study evaluated the Weather Research and Forecasting (WRF) model in dynamically downscaling selected Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations over Thailand during the baseline period of 1976–2005. A two-way nested WRF configuration was employed, with domains covering Southeast Asia (36 km) and Thailand (12 km) in the model. Model outputs were compared with gridded observations from the Climatic Research Unit (CRU TS), and spatial variations were analyzed across six administrative regions in Thailand. The WRF successfully reproduces broad climatological patterns, including the precipitation contrast between mountainous and lowland areas and the north–south gradient of temperature. Seasonal cycles of rainfall and temperature are generally well represented, although systematic biases remain, specifically the overestimation of orographic rainfall and a cold bias in high-elevation regions. The 12 km WRF simulations demonstrated improved special and temporal agreement with the CRU TS dataset, showing a national-scale wet bias (MBE = +17.14 mm/month), especially during the summer monsoon (+65.22 mm/month). Temperature simulations exhibited seasonal derivations, with a warm bias in the pre-monsoon season and a cold bias during the cool season, resulting in annual cold biases in both maximum (−1.25 C) and minimum (−0.80 C) temperatures. Despite systematic biases, WRF-CMIP5 downscaled framework provides enhanced regional climate information and valuable insights to support national-to-local climate change adaptation, resilience planning, and sustainable development strategies in Thailand and the broader Southeast Asian region. Full article

This study constructs a Stackelberg differential game model for green technology invest-ment in the food industry under a governmental coordination mechanism. The optimal dynamic strategies for local governments and enterprises are derived using Pontryagin’s maximum principle. The backward differential equation method is employed in this study. It is used to analyze the impact of shadow prices on the optimal decisions of both parties. Furthermore, the study examines how social welfare benefits influence the food quality levels within the jurisdiction of local governments. Based on these findings, optimal strategy pathways are proposed to achieve social welfare and enterprise profit maximization in the green transition process of both government and enterprises. The results indicate that a local government’s investment in food quality improvement significantly enhances the food quality levels within their jurisdictions—greater government investment leads to higher food quality. At the same time, food quality levels are positively correlated with the enterprises’ green technology capital investment. Additionally, consumer price sensitivity and sensitivity to price differences have a notable impact on product pricing. As consumers become more price-sensitive, product prices decrease accordingly, which, in turn, helps increase the market share of the enterprises’ products. Full article

The oil layers in the Dongying Formation offshore oilfield are severely contaminated. The near-wellbore reservoir pore throats are blocked, which seriously affects the development effect. It has become urgent to implement acidizing stimulation measures. However, the target reservoir is deeply buried, has high reservoir pressure, and is highly sensitive. These factors result in high pressure during acidizing operations, a long single-trip time for raising and lowering the tubing string, and high costs. Moreover, acid that is not promptly returned to the surface after acidizing can cause secondary pollution to the reservoir. This work proposes an integrated tubing string to perform reverse displacement and reverse squeeze. With this, acid can be injected into the formation through the annulus between the casing and tubing. The residual acid and its post-acidizing derivative residues are rapidly lifted to the surface by the reciprocating suction action of the return pump. Based on this, the structure and specifications of the acidizing-flowback tubing string are designed through the flow rate analysis method. The tubing string is mainly affected by mechanical effects, including buoyancy, piston effect, flow viscosity effect, helical bending effect, temperature difference effect, and expansion effect. The maximum deformations are 1.4 m, 1.9 m, 0.18 m, 2.7 m, 1.8 m, and 2.5 m, respectively. The total deformation is less than 3 m. Simulation results from three groups of oil wells at different depths indicate that the axial force of the tubing string ranges from 400 to 600 kN. The stress ranges from 260 to 350 MPa, deformation is 1.1–2.4 mm, and the safety factor exceeds 3.0. This can effectively ensure the safety of on-site operations. Based on the actual field conditions, the acidizing-flowback tubing string is evaluated. This verifies the effectiveness of the acidizing-flowback tubing string. This research provides an economical and efficient operation process for acidizing operations in the Dongying Formation offshore oilfield. It achieves the goal of removing reservoir contamination and provides guidance for the unblocking and stimulation of low-permeability and sensitive reservoirs in the middle and deep layers of offshore oilfields. Full article

Titanium dioxide (TiO₂) thin films sensitized with curcumin were fabricated to investigate the influence of sensitization on their spectroscopic, optical, and photocatalytic properties. TiO₂ films were prepared using different curcumin concentrations and characterized by FTIR, UV–Vis, and diffuse reflectance spectroscopy (DRS). The adsorption kinetics of curcumin on TiO₂ were analyzed, and the photocatalytic performance was evaluated through methylene blue (MB) photodegradation under visible-light irradiation. FTIR spectra confirmed the successful anchoring of curcumin onto the TiO₂ surface, while optical characterization revealed a significant enhancement in visible-light absorption. The band gap decreased from 3.2 eV (pure TiO₂) to 1.8 eV (curcumin-sensitized TiO₂). Furthermore, the curcumin adsorption onto semiconductor data fitted the pseudo-second-order kinetic model, yielding a maximum adsorption capacity of 12.0 mg·g⁻¹. Density Functional Theory (DFT) calculations indicated that ligand-to-metal charge transfer (LMCT) transitions are responsible for the improved visible-light response. Photocatalytic tests demonstrated that all curcumin-sensitized TiO₂ films were active under visible irradiation, confirming curcumin as an effective natural sensitizer for enhancing TiO₂-based photocatalytic coatings. Full article

Background/Objectives: Metformin is one of the most frequently used concomitant medications among prostate cancer (PCa) patients. However, the effects of metformin on all-cause and PCa-specific mortality among men diagnosed with advanced/metastatic PCa treated with androgen-deprivation therapy (ADT) remain poorly understood, but they may be specifically explained by emulating a target trial. Methods: We emulated a target trial of metformin therapy and survival using observational data on 7361 patients diagnosed with advanced PCa, who were treated with ADT, from the Surveillance, Epidemiology, and End Results (SEER)-Medicare database (2008–2019), with completed follow-up until 2020. We included patients with diabetes, and participants were assigned as either “initiator of metformin within 6 months after advanced PCa diagnosis” or “non-initiator of metformin.” We estimated mortality risks using Cox proportional hazards models with adjustment for risk factors via inverse probability weighting using both intention-to-treat and per-protocol analyses. Results: Over 13 years of follow-up, with a maximum 3 years of follow-up after PCa diagnosis, all-cause mortality occurred in 52 metformin initiators (47.7%) versus 3052 non-initiators (42.1%), while PCa-specific mortality occurred in 36 initiators (33.0%) versus 1919 non-initiators (26.5%). In the intention-to-treat analysis, metformin initiation was not associated with all-cause mortality (Hazard Ratio [HR] = 1.38, 95% CI: 0.98–1.95) or PCa-specific mortality (HR = 0.99, 95% CI: 0.63–1.55). Similarly, in per-protocol analysis, there was no evidence of risk reduction with all-cause (HR = 1.20, 95% CI = 0.80–1.81) or PCa-specific mortality (HR = 1.45, 95% CI = 0.88–2.38) after adjusting for time-varying covariates and allowing a 30-day gap for metformin discontinuation, adjusted for via inverse probability weighting. Conclusions: Our findings align with prior randomized trials showing no survival benefit of metformin in advanced PCa patients receiving ADT. Timing of metformin discontinuation also showed no significant effect. However, the small size of the metformin initiator group precluded subgroup analyses for hormone-sensitive (HSPC) and castrate-resistant prostate cancer (CRPC), limiting our ability to explore potential differential effects. Full article

In the semi-desert aeolian sand areas of Northern China, surface deformation monitoring with SAR is challenged by loss of coherence due to mobile dunes, seasonal vegetation changes, and large-gradient, nonlinear subsidence from underground mining. This study utilizes PALSAR-2 (L-band, 3 m resolution) and Sentinel-1 (C-band, 30 m resolution) data, applying InSAR and Offset tracking methods combined with differential, Stacking, and SBAS techniques to analyze deformation monitoring effectiveness and propose an efficient dynamic monitoring strategy for the Shendong Coalfield. The main conclusions can be summarized as follows: (1) PALSAR-2 data, which has advantages in wavelength and resolution (L-band, multi-look spatial resolution of 3 m), exhibits better interference effects and deformation details compared to Sentinel-1 data (C-band, multi-look spatial resolution of 30 m). The highly sensitive differential-InSAR (D-InSAR) can promptly detect new deformations, while Stacking-InSAR can accurately delineate the range of rock strata movement. SBAS-InSAR can reflect the dynamic growth process of the deformation range as a whole, and SBAS-Offset is suitable for observing the absolute values and morphology of the surface moving basin. The combined application of Stacking-InSAR and Stacking-Offset methods can accurately acquire the three-dimensional deformation field of mining-induced strata movement. (2) The spatiotemporal process of surface deformation caused by coal mining-induced strata movement revealed by InSAR exhibits good correspondence with both the underground mining progress and the development of ground fissures identified in UAV images. (3) The maximum displacement along the line of sight (LOS) measured in the mining area is approximately 2 to 3 m, which is close to the 2.14 m observed on site and aligns with previous studies. The calculated advance influence angle of the No. 22308 working face in the study area is about 38.3°. The influence angle on the solid coal side is 49°, while that on the goaf side approaches 90°. These findings further deepen the understanding of rock movement and surface displacement parameters in this region. The dynamic monitoring strategy proposed in this study is cost-effective and operational, enhancing the observational effectiveness of InSAR technology for surface deformation due to coal mining in this area, and it enriches the understanding of surface strata movement patterns and parameters in this region. Full article

The accurate characterisation of soil spatial variability is essential for the development of site-specific and sustainable agricultural practices. This study proposes an integrated methodology for effective soil mapping in Mediterranean environments. A preliminary agronomic context assessment (climate and pedology) was followed by electromagnetic induction (EMI) surveying at 14, 7 and 3 kHz. EMI data were processed by ordinary kriging to model spatial structure; the 14 kHz conductivity map—resulting from the frequency most sensitive to topsoil characteristics—was adopted to guide subsequent analysis. Sentinel-2 imagery acquired under bare-soil conditions was screened using the Bare Soil Index (BSI) to confirm vegetation absence, then processed to derive the Clay Index (CI). Guided by the 14 kHz kriged surface, twelve sampling points were selected with ESAP to capture both homogeneous zones and areas of maximum variability. Soil was sampled at 30 cm and analysed for texture, pH, electrical conductivity (EC_e) and carbon fractions. CI correlated strongly with apparent electrical conductivity (EC_a) (R² = 0.76; r = 0.87) and showed significant relationships with clay (R² = 0.69; r = 0.83). The proposed approach provides a robust and scalable alternative to conventional soil mapping, turning routine proximal and satellite data into decision-ready layers for site-specific management. Full article