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Mixture flow of particles and power-law fluid in round peristaltic tube

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Applied Mathematics and Mechanics(English Edition) 2019年第6期40卷 805-822页

作者： hailin yang Jianzhong LIN Xiaoke KU Institute of Fluid Engineering School of Aeronautics and AstronauticsZhejiang University

The erythrocyte and blood flowing in the blood vessel can be treated as the two-phase flow of the mixture of particles and a power-law fluid in a peristaltic *** the present work, the peristaltic transport of a power-law fluid and the suspension of particles in a tube is investigated by a perturbation method using the long wavelength approximation. The influence of different parameters on the velocity profile and streamlines is explored. Results show that there is a deflection of the flow field when the power-law index n = 0.5 or 1.5 compared with the Newtonian fluid where the trapping zone is symmetric to a certain cross section. The flux rate and reflux of the material are identified,and the conditions under which the reflux appears are determined. Moreover, a reflux phenomenon occurs near the wall. The trapping zone is related to not only the tube geometry and the flow flux but also the fluid properties. Both the length and width of the trapping zone increase with an increase in θ or φ. The trapping zone is more difficult to produce in the shear-thinning fluid than the shear-thickening fluid.

关键词： peristaltic transport two-phase flow power-law fluid perturbation method trapping phenomenon

Channel capacity and digital modulation schemes in correlated Weibull fading channels with nonidentical statistics

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Journal of Systems Engineering and Electronics 2007年第2期18卷 205-209页

作者： Xiao hailin Nie Zaiping yang Shiwen School of Electronic Engineering Univ. of Electronic Science and Technology of Chinas Chengdu 610054 P. R. China

The novel closed-form expressions for the average channel capacity of dual selection diversity is presented, as well as, the bit-error rate （BER） of several coherent and noncoherent digital modulation schemes in the correlated Weibull fading channels with nonidentical statisticS. The results are expressed in terms of Meijer＇s Gfunction, which can be easily evaluated numerically. The simulation results are presented to validate the proposed theoretical analysis and to examine the effects of the fading severity on the concerned quantities.

关键词： Average channel capacity Weibull fading channels Bit-error rate Digital modulation Nonidentical statistics.

Distribution of non-spherical nanoparticles in turbulent flow of ventilation chamber considering fluctuating particle number density

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Applied Mathematics and Mechanics(English Edition) 2021年第3期42卷 317-330页

作者： Ruifang SHI Jianzhong LIN hailin yang MingzhouYU Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou 310027China College of Mechanical and Electrical Engineering China Jiliang UniversityHangzhou 310028China

The Reynolds-averaged general dynamic equation(RAGDE)for the nanoparticle size distribution function is derived,including the contribution to particle coagulation resulting from the fluctuating *** equation together with that of a turbulent gas flow is solved numerically in the turbulent flow of a ventilation chamber with a jet on the wall based on the proposed model relating the fluctuating coagulation to the gradient of mean *** results are compared with the experimental *** results show that the proposed model relating the fluctuating coagulation to the gradient of mean concentration is reasonable,and it is necessary to consider the contribution to coagulation resulting from the fluctuating concentration in such a *** changes of the particle number concentration M_(0) and the geometric mean diameter dg are more obvious in the core area of the jet,but less obvious in other *** the increase in the initial particle number concentration m00,the values of M_(0) and the standard deviation of the particle sizeσdecrease,but the value of d_(g) *** decrease in the initial particle diameter leads to the reduction of M_(0) andσand the increase in d_(g).With the increase in the Reynolds number,particles have few chances of collision,and hence the coagulation rate is reduced,leading to the increase in M_(0) andσand the decrease in d_(g).

关键词： non-spherical nanoparticle fluctuating particle concentration ventilation chamber particle distribution

Tribological behavior and microstructural evolution of lubricating film of silver matrix self-lubricating nanocomposite

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Friction 2021年第5期9卷 941-951页

作者： Xiao KANG Shuang YU hailin yang yang SUN Lei ZHANG State Key Laboratory for Powder Metallurgy Central South UniversityChangsha 410083China Shanghai Institute of Astronautical Systems Engineering Shanghai 201108China

The aim of this study is to fabricate the nanocomposite with low friction and high wear resistance using binary solid lubricant *** microstructure and tribological performance of the nanocomposite are evaluated,and the composition and film thickness of the lubricating film are observed and analyzed by scanning electron microscopy(SEM)and X‐ray photoelectron spectroscopy(XPS).The nanocomposite exhibited improved tribological properties with a friction coefficient as low as 0.12 and a low wear rate of 2.17×10^(-6) mm^(3)/(N∙m)in high‐purity nitrogen *** sliding speed can increase lubricating film thickness,and the thickest lubricating film is approximately 125 *** the film thickness of the lubricating film exceeded 90 nm,the friction coefficient curves became *** compared with WS_(2),MoS_(2) can be more effective in forming the transfer layer on the worn surfaces at the initial stage of the tribological process.

关键词： lubricating film metal matrix self‐lubricating composite tribological behavior binary solid lubricants X‐ray photoelectron spectroscopy(XPS)

Additive manufacturing of a high strength Al-5Mg_(2)Si-2Mg alloy:Microstructure and mechanical properties

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Journal of Materials Science & Technology 2021年第32期91卷 215-223页

作者： hailin yang Yingying Zhang Jianying Wang Zhilin Liu Chunhui Liu Shouxun Ji State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Light Alloy Research Institute College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China BCAST Brunel University LondonUxbridgeMiddlesex UB83PHUnited Kingdom

A novel Al-5 Mg2 Si-2 Mg alloy was processed by selective laser melting(SLM) to understand its representative features of microstructural evolution and mechanical properties during additive manufacturing(AM). The as-SLM fabricated Al-5 Mg_(2) Si-2 Mg alloy is found to deliver much less hot cracks and other defects. Meanwhile, excellent mechanical property is also achieved, i.e. 452 ± 11 MPa for ultimate tensile strength, 295 ± 14 MPa for yield strength, and 9.3 ± 2.5% for elongation. Clearly, these mechanical properties are better than that obtained by high pressure die casting(HPDC), and better than some other alloys obtained by SLM. The as-SLM fabricated Al-5 Mg_(2) Si-2 Mg alloy is featured by the significantly refined microstructures in the compact primary α-Al, the divorced Mg_(2) Si eutectic networks distributing atα-Al grain boundaries, and some α-Al Fe Mn Si phase in association with eutectic Mg_(2) Si phase. The high strength and ductility of the alloy are attributed to its unique features including(a) the reduced solidification range,(b) the possible increase of the eutectic level in the microstructure, and(c) the shift of eutectic point and the maximum solubility point of Mg2 Si in Al matrix.

关键词： Aluminium alloys Additive manufacturing Selective laser melting Microstructure Mechanical properties

Antimony smelting process generating solid wastes and dust:Characterization and leaching behaviors

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Journal of Environmental Sciences 2014年第7期26卷 1549-1556页

作者： Xuejun Guo Kunpeng Wang Mengchang He Ziwei Liu hailin yang Sisi Li State Key Laboratory of Environment Simulation School of Environment Beijing Normal University

A large amount of solid waste has been produced by the antimony smelting process in the＂World Capital of Antimony＂, Xikuangshan area in China. This study comprehensively investigated the physical and chemical characteristics of the various solid wastes, as well as the leaching behavior of the solid wastes, which included water-quenched slag,arsenic-alkali residue, desulfurized slag and blast furnace dust. These four types of waste were enriched in a variety of heavy metals and metalloids and more specifically with As and Sb levels up to 8.6 × 104 and 3.16 × 105mg/kg, respectively, in arsenic-alkali residue. For desulfurized slag and water-quenched slag, the leaching concentration of Sb significantly exceeded the acceptable limits during the leaching tests using the toxicity characteristic leaching procedure and the synthetic precipitation leaching procedure. In addition, As leaching in arsenic-alkali residue was extraordinarily hazardous, being three orders of magnitude higher than the regulatory level of As. According to the results of the extraction tests, all the tested wastes were classified as hazardous waste.

关键词： Antimony smelter slag Arsenic BCR sequential extraction TCLP SPLP

Dynamic behavior of outburst two-phase flow in a coal mine T-shaped roadway:The formation of impact airflow and its disaster-causing effect

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International Journal of Mining Science and Technology 2023年第8期33卷 1001-1017页

作者： Liang Cheng Jiang Xu Shoujian Peng hailin yang Feng Jiao Bin Zhou Fazhi Yan State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China College of Safety Science and Engineering Xi’an University of Science and TechnologyXi’an 710054China College of Safety and Emergency Management Engineering Taiyuan University of TechnologyTaiyuan 030024China

The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst *** outburst test in a T-shaped roadway was conducted using a self-developed large-scale outburst dynamic disaster test *** investigated the release characteristics of main energy sources in coal seam,and obtained the dynamic characteristics of outburst two-phase flow in a ***,we established a formation model for outburst impact flow and a model for its flow in a bifurcated *** results indicate that the outburst process exhibits pulse characteristics,and the rapid destruction process of coal seam and the blocking state of gas flow are the main causes of the pulse *** outburst energy is released in stages,and the elastic potential energy is released in the vertical direction before the horizontal *** a straight roadway,the impact force oscillates along the *** an increase in the solid–gas ratio,the two-phase flow impact force gradually increases,and the disaster range extends from the middle of the roadway to the coal *** the area near the coal seam,the disaster caused by the two-phase flow impact is characterized by intermittent *** a bifurcated roadway,the effect of impact airflow on impact dynamic disaster is much higher than that of two-phase flow,and the impact force tends to weaken with increasing solid-gas *** impact force is asymmetrically distributed;it is higher on the left of the bifurcated *** an increase in the solid-gas ratio,the static pressure rapidly decreases,and the bifurcated structure accelerates the attenuation of static ***,secondary acceleration is observed when the shock wave moves along the T-shaped roadway,indicating that the bifurcated structure increases the shock wave velocity.

关键词： Multiphase flow Coal and gas outburst Dynamic disaster Impact airflow T-shaped bifurcated roadway Coal seam

Exceptional strength-ductility synergy of additively manufactured CoCrNi medium-entropy alloy achieved by lattice defects in heterogeneous microstructures

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Journal of Materials Science & Technology 2022年第32期127卷 61-70页

作者： Jianying Wang Jianpeng Zou hailin yang Lijun Zhang Zhilin Liu Xixi Dong Shouxun Ji State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Light Alloy Research Institute College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China Brunel Centre for Advanced Solidification Technology(BCAST) Brunel University LondonUxbridgeMiddlesex UB83PHUnited Kingdom

The selective laser melting(SLM)with subsequent cold rolling and annealing is used to produce high-density lattice defects and grain refinement in the CoCrNi medium-entropy alloys(MEAs).The superior comprehensive mechanical properties have been achieved in the as-SLMed CoCrNi alloy after rolling and *** as-SLMed alloys delivered the yield strength of 693.4 MPa,the ultimate tensile strength of 912.7 MPa and the fracture strain of 54.4%.After rolling with 70%reduction in thickness and annealing at 700℃for 2 *** yield strength,ultimate tensile strength and fracture strain reached 1161.6 MPa,1390.8 MPa and 31.5%,*** exceptional strength-ductility synergy is mainly attributed to the refined hierarchical microstructures with coarsening grains at a level of 30μm and ultrafine grains at a level of 1μm,and the heritage of dislocation-formed sub-grains and other lattice *** investigation demonstrates that the SLM with subsequent rolling and annealing is beneficial to fabricate high strength and ductile MEAs with single face-centered cubic(fcc)structure.

关键词： Medium-entropy alloys Selective laser melting Strength-ductility synergy Defects Microstructure

A super wear-resistant coating for Mg alloys achieved by plasma electrolytic oxidation and discontinuous deposition

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Journal of Magnesium and Alloys 2023年第8期11卷 2939-2952页

作者： Xixi Dong Mingxu Xia Feng Wang hailin yang Gang Ji E.A.Nyberg Shouxun Ji College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Brunel Centre for Advanced Solidification Technology(BCAST) Brunel University LondonUxbridge UB83PHUK School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Metallurgy and Materials University of BirminghamBirmingham B152TTUK State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Univ.Lille CNRSINRAECentrale LilleUMR 8207-UMET-UnitéMatériaux et TransformationsF-59000 LilleFrance Kaiser Aluminum Spokane ValleyWA 99216USA

Magnesium alloys are lightweight materials with great potential,and plasma electrolytic oxidation(PEO)is effective surface treatment for necessary improvement of corrosion resistance of magnesium ***,the∼14µm thick and rough PEO protection layer has inferior wear resistance,which limits magnesium alloys as sliding or reciprocating parts,where magnesium alloys have special advantages by their inherent damping and denoising properties and attractive *** a novel super wear-resistant coating for magnesium alloys was achieved,via the discontinuous sealing(DCS)of a 1.3µm thick polytetrafluoroethylene(PTFE)polymer layer with an initial area fraction(A_(f))of 70%on the necessary PEO protection layer by selective spraying,and the wear resistance was exceptionally enhanced by∼5500 times in comparison with the base PEO *** initial surface roughness(Sa)under PEO+DCS(1.54µm)was imperfectly 59%higher than that under PEO and conventional continuous sealing(CS).Interestingly,DCS was surprisingly 20 times superior for enhancing wear resistance in contrast to *** induced nano-cracks that splitted DCS layer into multilayer nano-blocks,and DCS also provided extra space for the movement of nano-blocks,which resulted in rolling friction and nano ***,DCS promoted mixed wear of the PTFE polymer layer and the PEO coating,and the PTFE layer(HV:6 Kg·mm^(−2),A_(f):92.2%)and the PEO coating(HV:310 Kg·mm^(−2),A_(f):7.8%)served as the soft matrix and the hard point,***,the dynamic decrease of Sa by 29%during wear also contributed to the super wear *** strategy of depositing a low-frictional discontinuous layer on a rough and hard layer or matrix also opens a window for achieving super wear-resistant coatings in other materials.

关键词： Magnesium alloy Coating Plasma electrolytic oxidation Discontinuous deposition Wear resistance Mechanism