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Tracer advection in a pair of adjacent side-wall cavities, and in a rectangular channel containing two groynes in series

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Journal of Hydrodynamics 2018年第4期30卷 564-572页

作者： Mohammad Mahdi Jalali Alistair g.l.Borthwick Institute for Energy Systems School of Engineering The University of Edinburgh

A model is presented of particle advection near groynes in an open channel. Open channel hydrodynamics is modelled using the shallow water equations, obtained as the depth-averaged form of Reynolds-averaged continuity and Navier-Stokes momentum equations. A lagrangian particle-tracking model is used to predict trajectories of tracer particles advected by the flow field, with bilinear interpolation representing the continuous flow field. The particle-tracking model is verified for chaotic advection in an alternating flow field of a pair of blinking vortices. The combined shallow flow and lagrangian particle-tracking model is applied to the simulation of tracer advection in flow past a pair of side-wall cavities separated by a groyne, and in an open rectangular channel containing a pair of parallel groynes oriented normal to the channel wall. The study is potentially useful in understanding mixing processes in shallow flow fields near hydraulic structures in wide rivers.

关键词： Shallow water equations lagrangian particle tracking chaotic advection blinking vortices side-wall cavities groynes

Active elastic metamaterials for subwavelength wave propagation control

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Acta Mechanica Sinica 2015年第3期31卷 349-363页

作者： Y.Y.Chen g.l.Huang Department of Mechanical and Aerospace Engineering University of Missouri

Recent research activities in elastic metamaterials demonstrate a significant potential for subwavelength wave propagation control owing to their interior locally resonant mechanism. The growing technological developments in electro/magnetomechanical couplings of smart materials have introduced a controlling degree of freedom for passive elastic metamaterials. Active elastic metamaterials could allow for a fine control of material physical behavior and thereby induce new functional properties that cannot be produced by passive approaches. In this paper, two types of active elastic metamaterials with shunted piezoelectric materials and electrorheological elastomers are proposed. Theoretical analyses and numerical validations of the active elastic metamaterials with detailed microstructures are pre- sented for designing adaptive applications in band gap structures and extraordinary waveguides. The active elastic metamaterial could provide a new design methodology for adaptive wave filters, high signal-to-noise sensors, and structural health monitoring applications.

关键词： Active elastic metamaterials Subwavelengthwave control Adaptive metastructures Smart materials

Vibrational behavior of isotropic plate structures in contact with a bounded fluid via unified formulation

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Chinese Journal of Aeronautics 2019年第4期32卷 921-937页

作者： F.g.CANAlES J.l.MANTARI Faculty of Mechanical Engineering Instituto de Investigación en Ingeniería Naval(IDIIN)Universidad Nacional de Ingenieria(UNI) Department of Mechanical Engineering University of New Mexico

This paper presents an analytical solution for free vibration analysis of thick rectangular isotropic plates coupled with a bounded fluid for various boundary conditions. In order to consider displacement theories of an arbitrary order, the Carrera Unified Formulation(CUF) is used. The eigenvalue problem is obtained by using the energy functional, considering plate and fluid kinetic energies as well as the potential energy of the plate. The Ritz method is used to evaluate the displacement variables, and the functions used in the Ritz series can be adjusted to consider any of the classical boundary conditions. The convergence of the solution is analyzed, and a validation of results considering open literature and 3D finite element software is performed. Parametric studies are carried out to obtain natural frequencies as a function of the side-to-thickness ratio, plate aspect ratio, fluid domain size, plate boundary conditions, and fluid-solid density ratio. Pressure and velocity in the fluid domain are evaluated in order to establish the consistency of the *** results for thick plates are obtained with a much lower computational cost compared to that of 3D finite element solutions.

关键词： Added mass Fluid-structure interaction Plate Ritz method Unified formulation Vibration

Different effects of economic and structural performance indexes on model construction of structural topology optimization

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Acta Mechanica Sinica 2015年第5期31卷 777-788页

作者： g.l.Yi Y.K.Sui College of Mechanical Engineering and Applied Electronics Technology Beijing University of Technology Department of Mechanical and Aerospace Engineering Seoul National University

The objective and constraint functions related to structural optimization designs are classified into economic and performance indexes in this *** influences of their different roles in model construction of structural topology optimization are also ***,two structural topology optimization models,optimizing a performance index under the limitation of an economic index,represented by the minimum compliance with a volume constraint（MCVC）model,and optimizing an economic index under the limitation of a performance index,represented by the minimum weight with a displacement constraint（MWDC）model,are *** on a comparison of numerical example results,the conclusions can be summarized as follows：（1）under the same external loading and displacement performance conditions,the results of the MWDC model are almost equal to those of the MCVC model;（2）the MWDC model overcomes the difficulties and shortcomings of the MCVC model;this makes the MWDC model more feasible in model construction;（3）constructing a model of minimizing an economic index under the limitations of performance indexes is better at meeting the needs of practical engineering problems and completely satisfies safety and economic requirements in mechanical engineering,which have remained unchanged since the early days of mechanical engineering.

关键词： Economic index Performance index Structural topology optimization models MCVC model MWDC model Safety and economy

Emerging role of A-kinase anchoring protein 5 signaling in reward circuit function

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Neural Regeneration Research 2025年第10期20卷 2913-2914页

作者： William J.Flerlage Mark l.Dell’Acqua Brian M.Cox Fereshteh S.Nugent Uniformed Services University of the Health Sciences Department of Pharmacology and Molecular TherapeuticsBethesdaMDUSA Department of Pharmacology University of Colorado School of MedicineAnschutz Medical CampusAuroraCOUSA

There is a strong evidence supporting the hypothesis of synaptic dysfunction as a major contributor to neural circuit and network disruption underlying emotional and mood dysregulation in psychiatric disorders(Simmons et al.,2024).Diverse sets of distinct molecular signaling pathways converge on the synapse to regulate synaptogenesis,synaptic function,and synaptic plasticity in brain regions and circuits through complex interactions organized by numerous multivalent protein scaffolds,including the family of proteins known as A-kinase anchoring proteins(AKAPs).

关键词： function supporting

Beneficiation of the gold bearing ore by gravity and flotation

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International Journal of Minerals,Metallurgy and Materials 2012年第2期19卷 106-110页

作者： Alim gül Olga Kangal Ayhan A. Sirkeci güven nal Mineral Processing Engineering Department Istanbul Faculty of Mines Technical University Istanbul 34469 Turkey

gold concentration usually consists of gravity separation, flotation, cyanidation, or the combination of these processes. The choice among these processes depends on the mineralogical characterization and gold content of the ore. Recently, the recovery of gold using gravity methods has gained attention because of low cost and environmentally friendly operations. In this study, gold pre-concentrates were produced by the stepwise gravity separation and flotation techniques. The Knelson concentrator and conventional flotation were employed for the recovery of gold. gold bearing ore samples were taken from gümüshane Region, northern east part of Turkey. As a result of stepwise Knelson concentration experiments, a gold concentrate assaying around 620 g/t is produced with 41.4wt% recovery. On the other hand, a gold concentrate about 82 g/t is obtained with 89.9wt% recovery from a gold ore assaying 6 g/t Au by direct flotation.

关键词： gold ore treatment beneficiation gold gravity separation flotation

DEFORMATION-INDUCED α2→γ TRANSFORMATION IN A HOT DEFORMED Ti-45A1-10Nb AllOY

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Acta Metallurgica Sinica(English letters) 1998年第1期11卷 19-24页

作者： J.g.Wang l.CZhang g.l.Chen H.Q.Ye Univ of Science and Technology Beijing Beijing China

High-resolution transmission electron microscope (HRTEM) was employed to investigate the deformation-induced α2→γ phase transformation phenomenon in a hot deformed Ti-45Al-10Nb alloy. Such a tronsformation can be nucleated either at α2/γ interfaces or at stacking faults on the basal planes of the α2 phase. The growth of deformation-induced γplate is accomplished by the motion of α/6 Shockley partials on alternate basal planes (0001)α2, and the α/6 Shockley partials move in coordination rather than sweep on (0001)α2 plane one by one. It appears that no atom transportation is involved in this stress-induced α2→γ transfromation.

关键词： intermetallic compound titanium aluminide Ti-45Al-10Nb alloy stress-induced phase transformation interface HRTEM

Microwave drying kinetics and quality characteristics of corn

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International Journal of Agricultural and Biological Engineering 2013年第1期6卷 90-99页

作者： Songül gürsoy Ruplal Choudhary Dennis g.Watson Department of Agricultural Machinery Faculty of AgricultureDicle University21280DiyarbakirTurkey Department of Plant Soil and Agricultural SystemsMC 4415Southern Illinois UniversityCarbondaleIL 62901 USA

In recent years,microwave(MW)drying has gained popularity as an alternative drying method for a wide variety of food and agricultural products because of increasing concerns over product quality and production ***,the determination of drying kinetics that accurately describes microwave drying characteristics is crucial for the optimization of operating parameters,performance improvement of the drying system and product *** objective of this study was to investigate the drying kinetics and the quality characteristics of corn kernels,especially the effects of different initial moisture contents(18.3%,26.3%,34.3%and 42.3%db),MW power levels(70,175 and 245 W)and exposure time(80 s and 120 s)on the drying kinetics,drying rate and various key quality *** results indicated that the increased drying rate at higher power levels(P3,245 W)reduced the drying time considerably but increased stress crack index and reduced *** addition,it reduced bulk density,true density and thousand grain weight(TgW).The germination rate of corn was the highest at MW power level P1(70 W),with the lowest drying rate and observed to decrease with increase in initial moisture *** reduction in exposure time decreased stress crack index and increased germination rate,bulk density and true *** correlation analysis among drying rate,germination,stress-crack index(SCI),bulk density,true density and TgW showed that increasing drying rate could lead to an increase in SCI and decrease in germination,bulk density and true density.

关键词： microwave drying corn stress-crack germination bulk density true density

Optimal Control of Service Rates of Discrete-Time(s,Q)Queueing-Inventory Systems with Finite Buffer

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Journal of Systems Science and Systems Engineering 2024年第3期33卷 261-280页

作者： l.Iniya B.Sivakumar g.Arivarignan School of Mathematics Madurai Kamaraj UniversityMaduraiTamilnaduIndia Department of Statistics Manonmaniam Sundaranar UniversityTirunelveliTamilnaduIndia

This article,we develop an optimal policy to control the service rate of a discrete time queueing-inventory system with finite *** customers arrive according to a Bernoulli process and the service time for the customers are *** the buffer size attains its maximum,any arriving new customers are considered to be *** customers are served one by one according to FCFS rule and each customers request random number of *** inventory is replenished according to a(s,Q)inventory policy with geometric lead *** main objectives of this article are to determine the service rates to be employed at each slot so that the long run expected cost rate is minimized for fixed inventory level and fixed buffer size and to minimize the expected waiting time for a fixed inventory level and fixed buffer *** problems are modelled as Markov decision *** establish the existence of a stationary policy and employ linear programming method to find the optimal service *** provide some numerical examples to illustrate the behaviour of the model.

关键词： Queueing-inventory system discrete time batch demand-Markov decision process