Search Results (10,215)

The gas reservoir of the Sinian Dengying Formation (Member 4) in Sichuan Basin exhibits extensive development of inter-clast dissolution pores and vugs within its carbonate reservoirs, characterized by low porosity (average 3.21%) and low permeability (average 2.19 mD). With the progressive development of the Moxi (MX)structure, the existing stimulation techniques require further optimization based on the specific geological characteristics of these reservoirs. Through large-scale true tri-axial physical simulation experiments, this study systematically evaluated the performance of three principal acid systems in reservoir stimulation: (1) Self-generating acid systems, which enhance etching through the thermal decomposition of ester precursors to provide sustained reactive capabilities. (2) Gelled acid systems, characterized by high viscosity and effectiveness in reducing breakdown pressure (18%~35% lower than conventional systems), are ideal for generating complex fracture networks. (3) Diverting acid systems, designed to improve fracture branching density by managing fluid flow heterogeneity. This study emphasizes hybrid acid combinations, particularly self-generating acid prepad coupled with gelled acid systems, to leverage their synergistic advantages. Field trials implementing these optimized systems revealed that conventional guar-based fracturing fluids demonstrated 40% higher breakdown pressures compared to acid systems, rendering hydraulic fracturing unsuitable for MX reservoirs. Comparative analysis confirmed gelled acid’s superiority over diverting acid in tensile strength reduction and fracture network complexity. Field implementations using reservoir-quality-adaptive strategies—gelled acid fracturing for main reservoir sections and integrated self-generating acid prepad + gelled acid systems for marginal zones—demonstrated the technical superiority of the hybrid system under MX reservoir conditions. This optimized protocol enhanced fracture length by 28% and stimulated reservoir volume by 36%, achieving a 36% single-well production increase. The technical framework provides an engineered solution for productivity enhancement in deep carbonate gas reservoirs within the G-M structural domain, with particular efficacy for reservoirs featuring dual low-porosity and low-permeability characteristics. Full article

Magnetorheological fluid exhibits shear-thinning behavior when subjected to high temperature environments exceeding 100 °C, which will significantly compromise the operational stability and reliability of the associated mechanical systems. To enhance the performance of magnetorheological fluid, this study selects soft magnetic particles, base carrier fluid, and surfactants based on their resistance to high temperatures and shear-thinning effects. A novel magnetorheological fluid with enhanced thermal stability and shear stability is subsequently developed by carefully selecting flake-shaped carbonyl iron powder, dimethyl silicone oil, and surfactant exhibiting both sedimentation stability and high temperature resistance. The apparent rheological properties and mechanical performance of the fluid are systematically evaluated. Experimental results indicate that the sedimentation rate of the prepared magnetorheological fluid is 3.86% after standing for 10 days, the thermal expansion rate at 200 °C is 12.8%, and the evaporation rate following repeated high temperature applications is only 0.66%. The shear yield stress of the prepared magnetorheological fluid is 31.2 kPa under the magnetic field of 817 mT. The prepared magnetorheological fluid demonstrates excellent thermal stability and shear-thinning resistance, which holds significant potential for enhancing the performance of magnetorheological devices in future applications. Full article

Predictive maintenance (PdM) is vital to maritime operations; however, the traditional deep learning solutions currently offered heavily depend on centralized data aggregation, which is impractical under the limited connectivity, privacy concerns, and resource constraints found in maritime vessels. Federated Learning addresses privacy by training models locally, yet most FL methods assume homogeneous client architectures and exchange full model weights, leading to heavy communication overhead and sensitivity to system heterogeneity. To overcome these challenges, we introduce FLUID, a dynamic, model-agnostic FL framework that combines client clustering, structured pruning, and student–teacher knowledge distillation. FLUID first groups vessels into resource tiers and calibrates pruning strategies on the most capable client to determine optimal sparsity levels. In subsequent FL rounds, clients exchange logits over a small reference set, decoupling global aggregation from specific model architectures. We evaluate FLUID on a real-world heavy-fuel-oil purifier dataset under realistic heterogeneous deployment. With mixed pruning across clients, FLUID achieves a global $R^2$ of 0.9352, compared with 0.9757 for a centralized baseline. Predictive consistency also remains high for client-based data, with a mean per-client MAE of 0.02575 ± 0.0021 and a mean RMSE of 0.0419 ± 0.0036. These results demonstrate FLUID’s ability to deliver accurate, efficient, and privacy-preserving PdM in heterogeneous maritime fleets. Full article

The utilization of ocean wave energy through environmentally sustainable technologies plays a pivotal role in the transition toward renewable energy sources. Among such technologies, the Submerged Horizontal Plate (SHP) stands out as a viable option for clean power production. This study focuses on the system’s application in a region on the southern coast of Brazil, identified as a potential site for future installation. To investigate this system, a three-dimensional numerical wave tank was developed to simulate wave behavior and hydrodynamic loads using the Navier–Stokes framework in the computational fluid dynamics software ANSYS FLUENT 2022 R2. The volume of fluid approach was adopted to track the free surface. The setup for wave generation in the numerical wave tank was verified against analytical solutions to ensure precision and validated under the SHP’s non-oscillating condition. To represent the oscillating condition, boundary conditions constrained motion along the x- and y-axes, allowing movement exclusively along the z-axis. A parametric analysis of 54 cases, with varying geometric configurations, wave characteristics, and submersion depths, indicated that the oscillating SHP configuration elongated perpendicular to wave propagation, combined with specific wave conditions, achieved a theoretical mean efficiency of 76.61%. Full article

Background/Objectives: This study investigated the correlation of oxidative stress biomarkers with the activity of idiopathic nephrotic syndrome (INS) in Slovenian children. Methods: In this prospective study, sequential plasma and urine samples from 20 children with INS in different phases of disease activity were taken: at first disease presentation or relapse (before glucocorticoid (GC) treatment), at time of remission achievement, and after discontinuation of GC treatment. This study measured oxidative stress biomarkers, such as 8-hydroxy-2′-deoxyguanosine (8-OHdG), hexanoyl-lysine (HEL) adduct, dityrosine (DiY), and 15-isoprostane F2t, using competitive enzyme-linked immunosorbent assay (ELISA) and assessed oxidative status using the FRAS 5 analytical system, which enables rapid photometric measurement of both oxidative and antioxidant capacity from biological fluids. Two complementary tests were performed: the d-ROMs test (derivatives of reactive oxygen metabolites) and the PAT (plasma antioxidant test). The oxidative stress index (OSI) was calculated as the ratio between them. Results: Concentrations of isoprostanes in urine were statistically significantly lower in patients at first disease presentation or relapse compared to time of remission achievement. Values of PAT test in serum were significantly highest after GC treatment. Values of d-ROMs test in serum were significantly lower at time of remission achievement compared to first disease presentation or relapse. Values of 8-OHdG, HEL, DiY (in plasma and urine), isoprostanes, and OSI in plasma did not statistically significantly differ in various phases of disease activity. Conclusions: Isoprostanes in urine and PAT in serum could serve as potential biomarkers of oxidative stress and disease activity in children with INS. Full article

Osteosarcopenia is a widespread geriatric condition resulting from the coexistence of osteoporosis and sarcopenia, where the connection between bone and muscle is, in part, driven by bone–muscle crosstalk. Given the close, reciprocal influence of muscle on nerve, and vice versa, it is not surprising that there are corresponding aging changes in the biochemistry and morphology of the neuromuscular junction (NMJ). Indeed, degeneration of motor neurons and progressive disruption of the neuromuscular connectivity were observed in old age. Extracellular vesicles (EVs) derived from human amniotic fluid stem cells (hAFSC), exhibiting antioxidant properties, which can also explain their anti-aging and cytoprotective effects, can be considered as potential treatment for age-related diseases. To study cell interactions under both healthy and pathological conditions occurring in musculo–skeletal apparatus, we developed a three-culture system exploiting the use of well-known transwell supports. This system allows both myotubes and neurons, eventually treated with EVs, and osteoblasts, induced to osteoporosis, to interact physically and biochemically. Collectively, this method allowed us to understand how the modifications induced in osteoblasts during bone disorders trigger a cascade of detrimental effects in the muscle and neuron parts. Moreover, we demonstrated the efficacy of hAFSC-EVs in preventing NMJ dysfunction, muscle atrophy, and osteoblast impairment. Full article

Background: Temporomandibular joint (TMJ) injections and arthrocentesis are commonly used minimally invasive methods for treating temporomandibular disorders (TMDs). Although considered safe, they can cause neurological complications. The aim of this systematic review was to synthesize all identified evidence for neurological adverse events following intra-articular TMJ interventions. Methods: This review was based on a systematic search with BASE, DOAJ, PubMed, SciELO, and Semantic Scholar on 28 May 2025. It included primary studies involving patients diagnosed with TMDs who underwent intra-articular injections into the TMJ or were treated with arthrocentesis, and in whom neurological adverse effects associated with the intra-articular intervention were reported. Studies reporting non-specific symptoms or unrelated systemic conditions were excluded. The risk of bias was assessed using the Joanna Briggs Institute’s critical appraisal tools. Results were presented in summary tables. Results: The search yielded five eligible studies comprising 319 patients, of whom 320 neurological adverse events were reported. Included studies comprised a randomized controlled trial, two retrospective studies, and two case reports. Four studies had a low risk of bias, and one had a moderate risk of bias according to the Joanna Briggs Institute appraisal tools. The proportion of patients affected ranged from 14% to 65% depending on the study design and intervention type. The most common adverse event was transient facial nerve (cranial nerve VII) paralysis, mainly involving the temporal and zygomatic branches. Less commonly reported complications involved the trigeminal nerve branches (V1, V3). There is also a single case of epidural hematoma with palsy of the oculomotor nerve (III). Most symptoms resolved spontaneously within a few hours to a few days. The use of local anesthesia and large volumes of irrigation (60 mL) during arthrocentesis increases the risk of complications. Attempts to explain the mechanisms of complications include local anesthetic diffusion, compression neuropraxia due to lavage fluid leakage, and corticosteroid neurotoxicity. One of the limitations of the study is the scarcity of data. Conclusions: Although most adverse events are mild and reversible, these findings highlight that precise, real-time guided injection and careful control of lavage volumes can minimize extra-articular spread of anesthetics or fluids, thereby reducing the likelihood of neurological complications. This study received no funding. PROSPERO ID number: CRD420251088170. Full article

This work investigates the intricate dynamics of the Carreau hybrid nanofluid’s inclined magnetohydrodynamic (MHD) flow, exploring both active and passive control modes. The study incorporates critical factors, including Arrhenius activation energy across a stretched sheet, chemical interactions, and nonlinear thermal radiation. The formulation of the boundary conditions and governing equations is inherently influenced by symmetric considerations in the physical geometry and flow assumptions. Such symmetry-inspired modeling facilitates dimensional reduction and numerical tractability. The analysis employs realistic boundary conditions, including convective heat transfer and control of nanoparticle concentration, which are solved numerically using MATLAB’s bvp5c solver. Findings indicate that an increase in activation energy results in a steeper concentration boundary layer under active control, while it flattens in passive scenarios. An increase in the Biot number ($Bi$) and relaxation parameter ($\mathsf{\Gamma }$) enhances heat transfer and thermal response, leading to a rise in temperature distribution in both cases. Additionally, the 3D surface plot illustrates elevation variations from the surface at low inclination angles, narrowing as the angle increases. The Nusselt number demonstrates a contrasting trend, with thermal boundary layer thickness increasing with higher radiation parameters. A graphical illustration of the average values of skin friction, Nusselt number, and Sherwood number for both active and passive scenarios highlights the impact of each case. Under active control, the Brownian motion’s effect diminishes, whereas it intensifies in passive control. Passive techniques, such as zero-flux conditions, offer effective and low-maintenance solutions for systems without external regulation, while active controls, like wall heating and setting a nanoparticle concentration, maximize heat and mass transfer in shear-thinning Carreau fluids. Full article

This study introduces an amphibious spherical robot equipped with a dual-propulsion system (ASR-DPS) and investigates its water-surface motion characteristics. Due to its distinctive spherical geometry, the robot exhibits markedly different hydrodynamic behavior compared to conventional vessels. A comparative analysis of the frontal wetted area is performed, followed by computational fluid dynamics (CFD) simulations to assess water-surface performance. The results indicate that the hemispherical bow increases hydrodynamic resistance and generates large-scale vortex structures as a consequence of intensified flow separation. Although the resistance is higher than that of traditional hulls, the robot’s greater draft and dual-propulsion configuration enhance stability and maneuverability during surface operations. To validate real-world performance, standard maneuvering tests, including circle and zig-zag maneuvers, are conducted to evaluate the effectiveness of the propeller-based propulsion system. The robot achieves a maximum surface speed of 1.2 m/s and a zero turning radius, with a peak yaw rate of 0.54 rad/s under differential thrust. Additionally, experiments on the pendulum-based propulsion system demonstrate a maximum speed of 0.239 m/s with significantly lower energy consumption (220.6 Wh at 60% throttle). A four-degree-of-freedom kinematic and dynamic model is formulated to describe the water-surface motion. To address model uncertainties and external disturbances, two control strategies are proposed: one employing model simplification and the other adaptive control. Simulation results confirm that the adaptive sliding mode controller provides precise surge speed tracking and smooth yaw regulation with near-zero steady-state error, exhibiting superior robustness and reduced chattering compared to the baseline controller. Full article

Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems account for a significant share of global energy demand, prompting intensive research into advanced thermal enhancement techniques. Among these, nanofluids—colloidal suspensions of nanoparticles in base fluids—have shown promise in boosting heat transfer performance. This review provides a structured and critical evaluation of nanofluid applications in HVAC&R systems, synthesizing research published from 2015 to 2025. A total of 200 peer-reviewed articles were selected from an initial pool of over 900 through a systematic filtering process. The selected literature was thematically categorized into experimental, numerical, hybrid, and AI/ML-based studies, with further classification by fluid type, performance metrics, and system-level relevance. Unlike prior reviews focused narrowly on thermophysical properties or individual components, this work integrates recent advances in artificial intelligence and hybrid modeling to assess both localized and systemic enhancements. Notably, nanofluids have demonstrated up to a 45% improvement in heat transfer coefficients and up to a 51% increase in the coefficient of performance (COP). However, the review reveals persistent gaps, including limited full-system validation, underexplored real-world integration, and minimal use of AI for holistic optimization. By identifying these knowledge gaps and research imbalances, this review proposes a forward-looking, data-driven roadmap to guide future research and facilitate the scalable adoption of nanofluid-enhanced HVAC&R technologies. Full article

Topology optimization is increasingly employed to design fluid flow systems capable of achieving optimal performance under specific constraints. This study presents a density-based topology optimization approach specifically tailored for second-order reactive flows. The fluid-solid distribution within the domain is represented by continuous design variables expressed as an inverse permeability field. An adjoint method is used to efficiently compute gradients of the objective function, enabling the application of gradient-based algorithms to solve the optimization problem. The methodology is validated on a benchmark bend-pipe case, reproducing known optimal geometry. Subsequently, the method is applied to optimize a system involving second-order chemical reactions, aiming to maximize a desired reaction while limiting undesirable side reactions. Results demonstrate significant performance improvements, achieving gains in reaction efficiency ranging from 90.4% to 98.7% for the porous geometries and from 94.6% to 105.2% for real geometries. The optimization strategy successfully generates flow configurations analogous to those observed in modern gas turbines, highlighting the practical relevance and potential impact of the developed methodology. Full article

Thirst is usually characterized as an unpleasant sensation provoking drinking of water. The purpose of the present review is to draw attention to the importance of thirst in overall regulation of body fluid homeostasis in health and pathology. Intensity of thirst is determined by signals generated in multiple groups of osmosensitive neurons engaged in dipsogenic and antidipsogenic activities, which are located in the brain cortex, the insula, the amygdala, the median preoptic area, the hypothalamic nuclei and the organum vasculosum laminae terminalis. Water ingestion is also influenced by signals generated in the cardiovascular system, the gastrointestinal system, the pancreas, the liver and the kidney and by changes of body temperature. Regulation of thirst engages the autonomic nervous system and several neuroactive factors synthetized in the brain and the peripheral organs. Among them are components of the renin–angiotensin system, vasopressin, atrial natriuretic peptide, cholecystokinin, ghrelin, gaseous transmitters, cytokines and prostaglandins. Experimental studies provide evidence that elevation of fluid osmolality, which is the most frequent cause of thirst, influences function of the voltage-gated sodium channel and calcium-dependent kinase II subunit alpha. Regulation of thirst may be inappropriate in old age and under some pathological conditions including infections, heart failure, diabetes insipidus, diabetes mellitus, and psychogenic disorders. The molecular background of the abnormal regulation of thirst in the clinical disorders is not yet sufficiently recognized and requires further examination. Full article

Transitioning to sustainable energy systems demands the creation of innovative methods that deliver dependable and effective renewable energy technologies. CSP systems that integrate parabolic trough designs with thermal energy storage (TES) systems provide essential solutions to overcome energy intermittency challenges. Molten salts serve dual functions as heat transfer fluids (HTFs) and thermal energy storage (TES) media, making them critical to CSP system performance improvements. The study introduces a hybrid MCDM framework that combines the CRITIC method for objective weighting with the SWARA approach for expert-adjusted weighting and utilizes an enhanced Lexicographic Goal Programming to evaluate molten salt options for off-grid parabolic trough systems. The evaluation process considered melting point alongside thermal stability while also assessing cost-effectiveness, recyclability, and safety requirements. The use of Pareto front analysis helped identify non-dominated salts, which then underwent a tiered optimization process emphasizing safety, performance, and sustainability features. Results confirm that the ternary nitrate composition Ca(NO₃)₂:NaNO₃:KNO₃ offers the best overall performance across all tested policy scenarios, driven by its superior thermophysical properties. Solar Salt (NaNO₃-KNO₃) consistently ranks as a robust second choice, excelling in economic and sustainability metrics. The proposed approach provides a flexible, policy-sensitive framework for material selection tailored to enhance the efficiency and sustainability of off-grid CSP systems and support the renewable energy objectives. Full article

Background/Objectives: To develop and evaluate an automated detection system for necrotizing soft tissue infection (NSTI) features on computed tomography (CT) images using the You Only Look Once version 10 (YOLOv10) model, aiming to improve diagnostic efficiency and surgical planning. Methods: This retrospective study included 31 patients with surgically confirmed NSTIs, spanning 2017–2023, from Chi Mei Medical Center, Taiwan. A total of 9001 CT images were annotated for four NSTI features: soft tissue ectopic gas, fluid accumulation, fascia edematous changes, and soft tissue non-enhancement. Model performance was evaluated using mean Average Precision (mAP), recall, and precision metrics. Results: The model achieved a mAP of 0.75, with recall and precision values of 0.74 and 0.72, respectively. Recall values for individual features were 0.76 for soft tissue ectopic gas, 0.66 for soft tissue non-enhancement, 0.92 for fascia edematous changes, and 0.68 for fluid accumulation. Conclusions: The YOLOv10-based system effectively detects four NSTI features on CT, including soft tissue ectopic gas, fluid accumulation, fascia edematous changes, and soft tissue non-enhancement. Full article

Seed amplification assays (SAA) targeting misfolded α-synuclein have emerged as powerful tools for the diagnosis and study of synucleinopathies, including Parkinson’s disease (PD), dementia with Lewy bodies, and multipßle system atrophy. These assays exploit the prion-like seeding properties of pathological α-synuclein to detect minute amounts of misfolded protein in biological specimens. the PubMed database was searched according to our study criteria, and 55 clinical studies comprised the final literature review. the majority of studies have focused on patients at various stages of PD, with cerebrospinal fluid (CSF) being the most commonly investigated biological specimen. Diagnostic utility was most pronounced in the CSF of PD patients, whereas results from other biological samples and across different synucleinopathies have been more modest. α-syn SAA demonstrate significant diagnostic potential in synucleinopathies. Additional applications may include monitoring disease progression. Future studies should explore the utility of α-syn SAA in alternative biological specimens, assess its performance across various synucleinopathies and other neurodegenerative diseases, and determine its comparative diagnostic value. Full article