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Efficient approaches of determining the motion of a spherical particle in a swirling fluid flow using weighted residual methods

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Particuology 2015年第6期13卷 68-74页

作者： Seiyed E. Ghasemi m. Vatani d.d. Ganji Young Researchers and Elite Club Qaemshahr Branch Islamic Azad University Qaemshahr lran department of mechanical Engineering Babol University of Technology Babol lran

The motion of a spherical particle released in a swirling fluid flow is studied employing the least-squares method and method of moments. The governing equations are obtained and solved employing the two methods. The accuracy of the results is examined against the results of a fourth-order Runge-Kutta numer- ical method. The effects of various parameters, namely the initial radius, initial radial velocity, initial angular velocity, and drag-to-inertia ratio, on the non-dimensional velocity profiles and particle position distribution are considered. The results show that the radial velocity increases over time while the angular velocity decreases, and that an increase in the initial radial velocity increases the particle radial distance and angular velocity but decreases the radial velocity profile.

关键词： Spherical particle Swirling flow Radial velocity Angular velocity Least-squares method method of moments

Computational Studies of Flow through Cross Flow Fans-Effect of Blade Geometry

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Journal of Thermal Science 2005年第3期14卷 220-229页

作者： m . GOVARdHAN d. LAKSHmANA SAmPAT School of mechanical Engineering Universiti Malaysia Sabah Sabah Malaysia ProfessorThermal Turbomachines Laboratory Department of Mechanical Engineering Indian Institute of Technology Madras Chennai India

This present paper describes three dimensional computational analysis of complex internal flow in a cross flow fan. A commercial computational fluid dynamics (CFd) software code CFX was used for the computation. RNG k-ε two equation turbulence model was used to simulate the model with unstructured mesh. Sliding mesh interface was used at the interface between the rotating and stationary domains to capture the unsteady interactions. An accurate assessment of the present investigation is made by comparing various parameters with the available experimental data. Three impeller geometries with different blade angles and radius ratio are used in the present study. maximum energy transfer through the impeller takes place in the region where the flow follows the blade curvature. Radial velocity is not uniform through blade channels. Some blades work in turbine mode at very low flow coefficients. Static pressure is always negative in and around the impeller region.

关键词： cross flow fans computational fluid dynamics quasi steady state multiple frames of reference

Search for microglia-specific peptides:advances in the discovery toolbox

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Neural Regeneration Research 2025年第2期20卷 471-472页

作者： Ivan Sarabia Kyle m.Koss department of Surgery University of ArizonaTucsonAZUSA

Uncontrolled and chronic inflammatory states in the central nervous system(CNS)are the hallmark of neurodegenerative pathology and every injury or stroke-related *** key mediators of these neuroinflammatory states are glial cells known as microglia,the resident immune cell at the core of the inflammatory event,and astroglia,which encapsulate inflammatory insults in proteoglycan-rich scar *** gliotic scar blocks significant portions of healthy axonal networking,preventing *** most neuroinflammation is exclusively based on the responses of said microglia,their phenotypes are suggested to follow those of macrophages;m1 and m2 are opposites of pro-and ***,microglial phenotypes have been identified to be on an inflammatory spectrum encompassing developmental,homeostatic,and reparative behaviors as opposed to their ability to affect devastating cell death cascades and scar tissue formation.

关键词： inflammation pathology death

modelling two-layer nanofluid flow in a micro-channel with electro-osmotic effects by means of Buongiorno’s model

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Applied mathematics and mechanics(English Edition) 2020年第1期41卷 83-104页

作者： m.d.K.NIAZI Hang XU State Key Lab of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE)School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong University

A fully developed steady immiscible flow of nanofluid in a two-layer microchannel is studied in the presence of electro-kinetic ***’s model is employed for describing the behavior of *** from the previous studies on two-layer channel flow of a nanofluid,the present paper introduces the flux conservation conditions for the nanoparticle volume fraction field,which makes this work new and unique,and it is in coincidence with practical *** governing equations are reduced into a group of ordinary differential equations via appropriate similarity *** highly accurate analytical approximations are *** physical quantities and total entropy generation are analyzed and discussed.A comparison is made to determine the significance of electrical double layer(EdL)effects in the presence of an external electric *** is found that the Brownian diffusion,the thermophoresis diffusion,and the viscosity have significant effects on altering the flow behaviors.

关键词： electrical double layer(EdL) entropy generation micro-channel nanofluid

Preliminary performance analysis and optimization based on 1d neutronics model for Indian dEmO HCCB blanket

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Plasma Science and Technology 2020年第8期22卷 184-191页

作者： d AGGARWAL C dANANI m Z YOUSSEF Institute for Plasma Research GandhinagarGujarat 382428India Homi Bhabha National Institute(HBNI) AnushaktinagarMumbai 400094India University of California-Los Angeles Los AngelesCA 90095United States of America

India,under its breeding blanket R&d program for dEmO,is focusing on the development of two tritium breeding blanket concepts;namely the lead-lithium-cooled ceramic breeder and the helium-cooled ceramic breeder(HCCB).The study presented in this paper focuses on the neutronic design analysis and optimization from the tritium breeding perspective of the HCCB *** Indian concept has an edge-on configuration and is one of the variants of the helium-cooled solid breeder blanket concepts proposed by several partner countries in *** Indian HCCB blanket having lithium titanate(Li2TiO3)as the tritium breeder and beryllium(Be)as the neutron multiplier with reduced-activation ferritic/martensitic steel structure aims at utilizing the low-energy neutrons at the rear part of the *** aim of the optimization study is to minimize the radial blanket thickness while ensuring tritium self-sufficiency and provide data for further neutronic design and thermal-hydraulic layout of the HCCB *** is found that inboard and outboard blanket thicknesses of 40 cm and 60 cm,respectively,can give a tritium breeding ratio(TBR)>1.3,with 60%6Li enrichment,which is assumed to be sufficient to cover potential tritium losses and associated *** results also demonstrated that the Be packing fraction(PF)has a more profound impact on the TBR as compared to 6Li enrichment and the PF of Li2TiO3.

关键词： dEmO helium-cooled ceramic breeder blanket neutronic optimization study tritium breeding ratio

Viscoelastic potential flow instability theory of Rivlin-Ericksen electrified fluids of cylindrical interface

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Journal of Ocean Engineering and Science 2024年第4期9卷 311-316页

作者： d.m.mostafa department of mathematics College of ScienceQassim UniversityPO Box 6644Buraidah 51452Saudi Arabia department of mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt

A linear electrohydrodynamic Kelvin-Helmholtz instability of the interface between two viscoelastic Rivlin-Ericksen fluids enclosed by two concentric horizontal cylinders has been studied via the viscoelastic potential flow *** dispersion equation of complex coefficients for asymmetric disturbance has been obtained by using normal mode *** stability criteria are analyzed theoretically and illustrated *** imaginary part of growth rate is plotted versus the wave *** influences of dynamic viscoelastic,uniform velocities,Reynolds number,electric field,dynamic viscosity,density fluids ratio,dielectric constant ratio and inner fluid fraction on the stability of the system are *** study finds its significance in Ocean pipelines to transfer oil or gas such as Eastern Siberia-Pacific Ocean oil pipeline.

关键词： Rivlin-Ericksen fluid Cylindrical flow Viscoelastic potential flow Electrohydrodynamics stability

dynamic modeling of a three-dimensional braided composite thin plate considering braiding directions

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 123-138页

作者： Chentong GAO Huiyu SUN Jianping GU W.m.HUANG College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics School of mechanical and Aerospace Engineering Nanyang Technological University Jiangsu Key Laboratory of Advanced Structural materials and Application Technology School of Materials Science and EngineeringNanjing Institute of Technology

Currently, there are a limited number of dynamic models available for braided composite plates with large overall motions, despite the incorporation of three-dimensional(3d) braided composites into rotating blade components. In this paper, a dynamic model of 3d 4-directional braided composite thin plates considering braiding directions is established. Based on Kirchhoff's plate assumptions, the displacement variables of the plate are expressed. By incorporating the braiding directions into the constitutive equation of the braided composites, the dynamic model of the plate considering braiding directions is obtained. The effects of the speeds, braiding directions, and braided angles on the responses of the plate with fixed-axis rotation and translational motion, respectively, are investigated. This paper presents a dynamic theory for calculating the deformation of 3d braided composite structures undergoing both translational and rotational motions. It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications.

关键词： braiding direction composite thin plate dynamic model large overall motion O313.7 three-dimensional (3d) braided composite

Jet flows from bubbles during subcooled pool boiling on micro wires

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Science China(Technological Sciences) 2005年第4期48卷 385-402页

作者： d. m. Christopher Laboratory of Phase Change and Interfacial Transport Phenomena Department of Thermal Engineering Tsinghua University Beijing 100084 China

An experimental investigation was conducted on subcooled nucleate boiling on ultra-small wires having diameters of 25―100 μm. High-speed photography and laser PIV (Particle Image Velocimetry) technology were used to visually observe the bubble dynamics. For highly subcooled boiling at moderate heat fluxes, the bubbles generally remained attached to the micro heating wires and bubble-top jet flows were clearly observed. Smaller bubbles usually had stronger bubble-top jet flows, while larger bubbles seemed to produce multi-jet flows. The structures of the bubble-top jet flows, as well as multi-jet flows, were proposed from the experimental observation. A model was developed to describe jet flow phenomena from bubbles on micro wires. Numerical simulations for bubbles having diameter of 0.03 and 0.06 mm showed that both the bubble-top and multi-jet flows were induced by a strong marangoni effect due to high temperature gradients near the wire. The predicted velocity magnitudes and flow structures agreed very well with experimental measurements. The bubble size relative to the wire is an important factor affecting the jet flow structure. For a 0.03 mm bubble on a 0.1 mm wire, only a bubble-top jet flow forms, while a complex multi-jet flow pattern forms around the bubble with a weak bubble-top jet and two side jet flows for a 0.06 mm bubble.

关键词： subcooled boiling, bubble, multi-jet, jet flow, PIV, marangoni, CFd.

migration and Pathological Journeys: A Case Report of 5 Patients at the National Hospital in Niamey

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Open Journal of Psychiatry 2025年第1期15卷 24-34页

作者： Ousseyni Zika Oumou moussa djibrilla Ataigba Iréti Néthania Elie Salifou A. m. mobarak daou mamane Nanéma désiré Abdou Bakari Sangaré Ismaël Coulibaly modibo douma maiga djibo Ouédraogo Arouna Faculty of Health Sciences Abdou moumouni University Niamey Niger Faculty of Health Sciences Andr Salifou University Zinder Niger Faculty of medicine and Nursing and Obstetrics Training Institute University of Parakou Parakou Bnin Health Sciences Training and Research Unit (UFR/SdS) Joseph Ki-Zerbo University Ouagadougou Burkina Faso Ecole Normale Suprieure Abdou Moumouni University Niamey Niger

This study aims to explore the unconscious motivations underlying migration in Niger, with an emphasis on understanding the phenomenon of pathological travel. Its aim is to identify the unconscious factors of pathological travel among migrants. Pathological travel, as discussed in the scientific literature on psychopathology, is characterised by movements initiated under the influence of delusions, hallucinations or other serious psychiatric disorders. The aim of this research is to contribute to our understanding of how these unconscious factors influence migration decisions. Using a retrospective analysis of five cases, this study examines the psychological and psychiatric dimensions of migration, particularly among patients referred to the psychiatry department of the Niamey National Hospital between 2017 and 2018. The five cases analysed, representing 12% of a cohort of 40 migrant patients, suffered from chronic psychotic disorders, including schizophrenia and chronic hallucinatory psychosis. By means of diagnostic interviews and categorical sorting, three main unconscious motivations were identified: the delusional state with themes of filiation and persecution, the hallucinations that dictated the travel behaviour, and the dissociative states manifested by depersonalisation and derealisation. It also emerges from this analysis that pathological travel often involves prolonged journeys on foot and without purpose. Thus, untreated mental illness plays a significant role in shaping and influencing individual and social behaviour. The results of this study have important implications for public health and migration policy. They highlight the need to integrate health assessments into migration management systems, particularly in regions serving as transit hubs for migrants. The research also highlights the need for culturally sensitive psychiatric interventions to address the interaction between pre-existing mental disorders and migration. This study contributes to

关键词： migration mental Illness Pathological Journeys Unconscious Psychological motivations Niger