Abstract Objective To investigate if papaverine improves anastomotic stenosis, promotes microcirculation, and enhances the prognosis of patients with moyamoya disease (MMD). Methods This study enrolled 120 patients with MMD, 60 individuals in the experimental group receiving intraoperative and postoperative treatment with papaverine, and the control group who did not receive papaverine, respectively. We performed transcranial Doppler (TCD), computed tomography perfusion (CTP), and digital subtraction angiography (DSA) before and within 3 days postoperatively to assess the effectiveness of papaverine. TCD measurements included the internal diameter and blood flow velocity of all patients’ superficial temporal, internal carotid, and vertebral arteries. CTP was used to evaluate perfusion in various brain regions, including the frontal, temporal, parietal, and occipital lobes. DSA was used to assess the collateral vessel proliferation in patients diagnosed with MMD. Patient prognosis was evaluated using the Modified Rankin Scale (mRS) score, Random Forest analysis, and monitoring for potential complications. Results Postoperative examination of the parietal and temporal lobes using CTP revealed that the experimental group exhibited shorter time-to-peak, shorter mean transit time, and a higher cerebral blood volume than the control group. Postoperatively, we observed a more significant increase in collateral circulation in the experimental group due to postoperative collateral grading. mRS scores in both groups were statistically different. However, no statistical difference was observed between both groups regarding complications. Conclusions These findings suggest that adding papaverine to revascularisation procedures in patients with MMD promotes anastomotic patency and enhances collateral circulation proliferation, ultimately leading to improved prognosis.

Numerical investigation of the effects of nozzle geometry on internal cavitation flow and near-field spray

Industrial solid waste based sulfoaluminate materials for pollution cutoff wall: Biochar-driven hydration acceleration, microstructural densification, and life-cycle environmental benefits.

Research on internal flow characteristics of gas-liquid two-phase flow in reactor coolant pump

Numerical and experimental investigations of internal flow characteristics of n-butane adsorption in a carbon canister

Selectivity of commercial polymeric microfiltration membranes is limited by internal flow channeling

Three-dimensional internal flow characteristics of bypass shock-induced thrust vector control

Tip leakage flow, as one of the major sources of loss in axial compressors, plays a crucial role in determining compressor efficiency and stability. During long-term operation, blade surface degradation caused by fouling, erosion, and wear alters the internal flow characteristics of the compressor, leading to a more complex secondary flow loss mechanism. In this study, linear cascade experiments are conducted to investigate the performance deterioration caused by tip-surface fouling under varying attack angles and tip clearances. Aerodynamic measurements are obtained using a five-hole probe, while oil-flow visualization is employed to reveal flow structures. The research results indicate that surface roughness at the blade tip increases momentum loss in the near-tip region, reducing axial momentum within the vortex core. This roughness-induced increase in near-tip momentum loss aggravates tip-region blockage, elevates the total pressure loss coefficient, and ultimately deteriorates the compressor's aerodynamic performance. As the tip clearance decreases and the attack angle increases, the performance degradation becomes more pronounced, with the maximum aerodynamic loss increment reaching 6.9% at a 1 mm clearance and an attack angle of +8°. Furthermore, the influence of tip-surface roughness is mainly confined to the near-tip region—within approximately 15% of the blade span—indicating that its primary effect manifests through modification of the leakage flow pattern rather than a global change in the secondary flow structure.

An experimental study on the internal flow field characteristics in aquaculture vessel tanks under sloshing conditions

Study on the internal flow characteristics of V-regulating ball valve for hydrogen fuel engine

Internal flow interaction between three parallel modules within a hypersonic inlet/isolator

To address the issue of climate change caused by greenhouse gases, extensive research has been conducted on technologies for separating and capturing carbon dioxide. This study aimed to investigate the internal flow behavior and relative spatial distribution of CO2-related features inside a vortex tube using the Schlieren method. Due to the presence of numerous components in a typical counter-flow vortex tube that may cause optical refraction along the measurement path, a simplified tube with a single nozzle was designed and manufactured for the experiments. The experiments consisted of CO2 single-phase flow and air–CO2 mixture flow tests. Images captured during the experiments were processed using Gaussian filtering and background correction to enhance the visibility of boundary layers and internal flow structures. Based on the pixel intensity values of the processed Schlieren images, relative intensity distributions associated with CO2-related flow behavior inside the tube were estimated and visualized. The experimental results revealed that, in both CO2 single-phase and air–CO2 mixture flows, regions of relatively high Schlieren intensity consistently appeared at specific locations within the tube. These observations indicate that the internal flow structure and relative distribution patterns are sensitive to the local flow features near the nozzle region under the tested conditions. The temporal evolution of the normalized Schlieren pixel intensity and its standard deviation was quantitatively evaluated, in a relative sense, to characterize the development of vortex flow structures under different operating conditions. The proposed visualization and analysis framework provides a systematic qualitative approach, supported by relative quantitative indicators, for investigating vortex-induced flow behavior. This framework may serve as a foundation for future studies that integrate complementary diagnostics and numerical analyses to further explore the vortex-based gas separation mechanism.

The transient cavitation flow within the nozzle of a high-pressure micro-size injector is characterized by high turbulence and multi-phase. The inception and development of this flow are markedly affected by the nozzle geometries, which exert a direct influence on the injector nozzle reliability and the spray characteristics. This study presents a comprehensive evaluation of nozzle performance in terms of flow coefficient, spray patterns and cavitation erosion, with a particular focus on the sensitivity of the nozzle parameters using a combination of optical experiment, numerical simulation, and machine learning. According to the sensitivity analysis, the parameters of hole taper coefficient, needle lift and the combined needle lift and hole height have the most significant influence on the nozzle performances. Furthermore, a multi-objective optimization of the parameters of a nine-hole marine nozzle was conducted based on the Radial Basis Function neural network and the Non-dominated Sorting Genetic Algorithms-II genetic algorithm. Results present that the flow coefficient of the fitness-optimal nozzle shows an approximately 25% increase, while the near-nozzle liquid phase diffusion angle simultaneously demonstrates a marked increase exceeding 70%, and the cavitation erosion risk is sharply reduced.

ABSTRACT To investigate the influence of the gas-liquid separation chamber (GLSC) volume on a self-priming performance, numerical studies are conducted to examine the effects of three different initial water storage volumes on a self-priming pump based on Volume of Fluid (VOF) model. The findings indicate that the size of GLSC has an insignificant impact on the self-priming time required for the pump to achieve self-priming. Furthermore, the chamber volume does not significantly influence the external characteristic parameters; however, it does result in notable differences in the internal flow characteristics within the pump. During the rapid air intake phase and oscillatory exhaust phase, there are marked differences in the proportion of the gas phase within the pump as influenced by the size of GLSC.

Nowadays, aerospace components are increasingly moving towards larger size, lighter weight, and multi-functional integration. Among manufacturing technologies, 3D printing technology has become a commonly used intelligent method in the aerospace field, enabling the integrated forming of complex components through layer-by-layer material deposition. This paper introduces the principles, characteristics, and aerospace applications of Selective Laser Melting (SLM), Laser Melting Deposition (LMD), Electron Beam Selective Melting (EBSM), and Wire and Arc Additive Manufacturing (WAAM). SLM, due to its high forming accuracy and densification, is preferred for precision components with complex internal flow channels and lattice structures. LMD demonstrates significant process flexibility and advantages in component remanufacturing, functionally graded materials, and rapid medium-scale component formation. EBSM, utilizing a high-vacuum environment and powder preheating, effectively controls thermal stress, supporting low-stress forming of large, high-performance titanium alloy components. WAAM provides high deposition rates and cost-efficiency, suitable for rapid near-net shaping of meter-scale extra-large structural components. Combined with typical cases, the advantages of this technology in manufacturing are analyzed. Future development directions such as material development and production line construction are prospected.

The production of a stable and uniform spray is a primary concern in fuel atomization applications, such as in fluid catalytic cracking reactors, directly affecting the process quality and gas emissions. However, depending on nozzle geometry and operating conditions, undesired pulsed spray behavior may occur. This phenomenon originates from the internal multiphase flow interaction in Y-jet nozzles and leads to unstable sprays. Understanding the formation of spray pulsations is challenging due to limited internal flow visualization in the nozzle and the fast dynamics involved. Accordingly, this work elucidates the mechanisms of the pulsed spray formation through 3D transient numerical multiphase simulations inside a mixing chamber. The model is validated against internal pressure measurements and applied to investigate the internal mixing behavior across several operating conditions. Results show that the liquid-to-gas momentum flux ratio governs the internal flow regimes. A higher liquid momentum flux obstructs the gas flow, leading to periodic spray bursts when the gas overcomes the liquid back pressure. The simulations also reveal self-sustained oscillatory flow patterns and cyclic transitions between gas penetration and liquid accumulation, which produce periodic pressure fluctuations and nozzle discharge pulsations. The findings offer valuable guidance for optimizing nozzle operation and geometry to suppress pulsation and improve atomization performance.

The swing scraper pump-motor, a novel positive displacement pump, combines compact structure, high efficiency, and strong adaptability for industrial applications. FSI (fluid–structure interaction) refers to the interaction between fluid dynamics and structural mechanics, where fluid flow affects the structure, and the structure's deformation influences the fluid flow. However, the complex internal flow and scraper–rotor coupling present challenges in performance evaluation and life prediction. This study conducts a computational investigation of flow field characteristics and fatigue behavior. Using particle-based XFlow, the transient internal flow is simulated at varying rotational speeds. Results indicate that increasing speed enhances flow velocity, while pressure distribution becomes more uniform at the rated speed of 1666 r/min. Although volumetric efficiency slightly decreases, it remains above 80%, confirming favorable hydraulic performance. Turbulence-induced unsteadiness causes pressure reduction in the high-pressure chamber at higher speeds. FSI is further analyzed by coupling XFlow with Workbench Dynamics, and stress-time data are imported into nCode DesignLife for fatigue assessment. The rotor exhibits a predicted life of about 8547 h, while the scraper shows only 4625 h, identifying it as the critical fatigue component. These findings provide guidance for structural optimization and predictive maintenance of the swing scraper pump, improving reliability, efficiency, and safety.

Background: This study aimed to evaluate the right and left internal mammary artery (RIMA and LIMA) flow dynamics in coronary artery bypass grafting (CABG) candidates using the Doppler ultrasound and explore their associations with clinical and echocardiographic factors. Methods: This prospective observational study enrolled 60 patients scheduled for CABG at Dong Nai General Hospital from January 2023 to December 2024. Doppler ultrasound assessed internal mammary artery (IMA) size, peak systolic velocity (PSV), time-averaged mean velocity (TAMV), flow volume, and atherosclerotic changes. Statistical analyses included paired t-tests, multivariable regression, and correlation analyses. Results: The RIMA was slightly larger than the LIMA (2.3 ± 0.3 mm vs 2.2 ± 0.3 mm, P = .042), with no significant differences in PSV, TAMV, or flow volume. Mean flow volumes were 28.0 ± 12.8 mL/min (RIMA) and 26.2 ± 11.7 mL/min (LIMA). Atherosclerosis was rare (1.7% RIMA, 0% LIMA). Smoking (β = 0.32, P = .014) and dyslipidemia (β = 0.28, P = .029) predicted higher RIMA flow, while age predicted lower LIMA flow (β = −0.35, P = .008). Conclusions: Preoperative Doppler assessment indicated minimal statistical differences but no clinical disparities between the RIMA and LIMA. Individualized preoperative assessment and risk factor optimization remain essential to improve conduit selection and surgical outcomes in CABG.

The 7th International Conference on Plant Vascular Biology 2025 (PVB2025) took place at the KKR Hotel Osaka from July 7th to July 12th. The conference attracted 169 participants from 20 countries, including 105 attendees from outside Japan. PVB2025 featured 12 plenary scientific sessions, 23 invited talks, 31 contributed talks selected from submitted abstracts, and 89 poster presentations. Plant vascular biology is a crucial area of plant science, as vascular systems transport essential resources that plants need for survival. These systems also function as a communication network, facilitating internal and external information flow at the whole-body level. Participants at PVB2025 aimed to share their latest findings in this field. Additionally, the conference emphasized the importance of inspiring and encouraging young scientists who will become the next generation of community leaders. To support this initiative, we offered five travel awards and five Best Poster Awards to undergraduate students, graduate students, and early-career professionals. Overall, PVB2025 successfully fostered discussions and collaborations in plant vascular biology research while allowing participants to experience the unique and vibrant culture of Osaka through "eating and talking till you drop."

Semi-open impeller sewage pumps are widely used in fields such as municipal wastewater treatment. However, they often face performance degradation and operational instability when conveying solid–liquid two-phase flows containing solid particles. This study aims to systematically elucidate the influence mechanisms of particle diameter (0.5–3.0 mm) and volume fraction (1–20%) on the external characteristics and internal flow field of semi-open impeller sewage pumps, providing a theoretical basis for optimizing their design and operational stability. Using an 80WQ4QG-type sewage pump as the research subject, this study employed a combination of numerical simulation and experimental research. The standard k-ε turbulence model coupled with the Discrete Phase (Particle) approach was adopted for multi-condition solid–liquid two-phase flow simulations. Furthermore, two-way analysis of variance (two-way ANOVA) was utilized to quantify the main effects and interaction effects of the parameters. The results indicate that the pump head and efficiency generally exhibit a decreasing trend with increasing particle diameter or volume fraction, with particle diameter exerting a more pronounced effect (p < 0.01). When the particle diameter increased to 3.0 mm, the head decreased by 5.66%; when the volume fraction rose to 20%, the head decreased by 4.17%. It is noteworthy that the combination of a 0.5 mm particle diameter and a 20% volume fraction resulted in an abnormal increase in head, suggesting a possible flow pattern optimization under specific conditions. Analysis of the internal flow field reveals that coarse particles (≥1.5 mm) intensify the pressure gradient disparity between the front and rear shroud cavities of the impeller, thereby increasing the axial thrust. A high volume fraction (≥10%) promotes pronounced flow separation in the volute tongue region and exacerbates the risk of localized erosion at the outlet.