检索结果-南通市图书馆

Submicron particle sizing by aerodynamic dynamic focusing and electrical charge measurement

在线全文

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 105-111页

作者： Zhongchao Tan Raheleh Givehchi Alena Saprykina department of mechanical & mechatronics engineering University of Waterloo department of mechanical and Manufacturing engineering University of Calgary

Principles of a novel submicron particle sizing technology are first introduced followed by experimental validation. The sizing was accomplished by coupling aerodynamic particle focusing and maximum ion measurement. Experimental results showed that the prototype could detect particle sizes down to 40 nm in diameter. Comparison between the prototype and a scanning mobility particle sizer using identical polydisperse particles showed that the measurements agreed well for the tested particles.

关键词： Submicron particle Particle sizing Aerodynamic focusing Particle charging

Role of heat balance on the microstructure evolution of cold spray coated AZ31B with AA7075

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2021年第4期9卷 1467-1478页

作者： Bahareh Marzbanrad Mohammad Hadi Razmpoosh Ehsan Toyserkani Hamid Jahed mechanical and mechatronics engineering department University of WaterlooCanada

A promising solid-state coating mechanism based on the cold spray technique provides highly advantageous conditions on thermal-sensitive magnesium *** study the effect of heat balance in cold spray coating on microstructure,experiments were designed to successfully coat AA7075 on AZ31B with two different heat balance conditions to yield a coated sample with tensile residual stress and a sample with compressive residual stress in both coating and *** effects of coating temperature on the microstructure of magnesium alloy and the interfaces of coated samples were then analyzed by SEM,EBSD,TEM in high-and low-heat input coating *** interface of the AA7075 coating and magnesium alloy substrate under both conditions consists of a narrow-band layer with very fine grains,followed by columnar grains of magnesium that have grown perpendicular to the *** higher temperatures,this layer became *** intermetallic phase was detected at the interface under either *** is shown that the microstructure of the substrate was affected by coating temperature,leading to stress relief,dynamic recrystallization and even dynamic grain growth of magnesium under high *** the heat input and increasing the heat transfer decreased microstructural changes in the substrate.

关键词： Cold spraying Heat balance Microstructural analysis Coating interface Magnesium Alloy AZ31B Residual Stress

Personalization for Massive Product Innovation Using Open Architecture

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2018年第2期31卷 12-24页

作者： Qing-Jin Peng Yun-Hui Liu Jian Zhang Pei-Hua Gu department of mechanical engineering University of Manitoba department of mechatronics engineering Shantou University

Product innovation is creation of new concepts to plan and realize technological and functional details in the product to satisfy market and customer needs. One of the key drivers to product innovation is reactions of the product to users’ needs. Product innovation needs a cognitive design method based on needs of variant users for the product personalization. In this paper, an open concept is introduced to provide ways to meet user’s individual need in product lifespan. It is for industries to propose product concepts based on open sources, develop and support the product on the public capability. Using the open concept in the product architecture, called open?architecture product(OAP), can improve the product personalization leading to massive product innovation. To promote this promise of the OAP, effective methods are discussed for the OAP development. This paper introduces research on OAPs using adaptable design methods to meet product personalization. Adaptable design is based on the modular structure for product adaptability using function modules and adaptable interfaces. The proposed method provides solutions for planning modules and implementation of OAPs. Methods of OAP module planning, detail and interface design are described for transformation of product concepts into physical structures. A multiple?purpose electrical car is developed in a case study to show effectiveness of the proposed method.

关键词： Product design Personalization Massive innovation Open architecture Adaptable design

Experimental investigation and optimization of weld bead characteristics during submerged arc welding of AISI 1023 steel

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2019年第1期15卷 72-82页

作者： Ankush Choudhary Manoj Kumar Deepak Rajendra Unune department of mechanical-mechatronics engineering The LNM Institute of Information Technology

Submerged arc welding(SAW), owing to its high deposition rate and high welding quality, is widely used in the fabrication of pressure vessel, marine vessel, pipelines and offshore structures. However, selection of an optimum combination of welding parameters is critical in achieving high weld quality and productivity. In this work, initially, the SAW experiments were performed using fractional factorial design to analyze the effect of direct and indirect input parameters, namely, welding voltage, wire feed rate,welding speed, nozzle to plate distance, flux condition, and plate thickness on weld bead geometrical responses viz. bead width, reinforcement, and penetration. The bead on plate technique was used to deposit weld metal on AISI 1023 steel plates. The effect of SAW input parameters on response variables were analyzed using main and interaction effects. The linear regression was used to develop the mathematical models for the response variable. Then, the multi-objective optimization of input parameters was carried out using desirability approach, genetic algorithm and Jaya algorithm. The Jaya algorithm offered better optimization results as compared to desirability approach, genetic algorithm.

关键词： Submerged arc welding Optimization Regression Genetic algorithm Jaya algorithm

Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第01期 139-156页

作者： H.HOSSEINI O.BALILASHAKI department of mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词：

Assessment and validation of liquid breakup models for high-pressure dense diesel sprays

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers in Energy 2016年第2期10卷 164-175页

作者： Yi REN Xianguo LI department of mechanical and mechatronics engineering University ofWaterloo Waterloo Ontario Canada

Liquid breakup in fuel spray and atomization significantly affects the consequent mixture formation, combustion behavior, and emission formation processes in a direct injection diesel engine. In this paper, different models for liquid breakup processes in high-pressure dense diesel sprays and its impact on multi-dimensional diesel engine simulation have been evaluated against experi- mental observations, along with the influence of the liquid breakup models and the sensitivity of model parameters on diesel sprays and diesel engine simulations. It is found that the modified Kelvin-Helmholtz （KH）-Rayleigh-Taylor （RT） breakup model gives the most reasonable predicted results in both engine simulation and high-pressure diesel spray simulation. For the standard KH-RT model, the model constant Cbl for the breakup length has a significant effect on the predictability of the model, and a fixed value of the constant Cbl cannot provide a satisfactory result for different operation conditions. The Taylor-analogy- breakup （TAB） based models and the RT model do not provide reasonable predictions for the characteristics of high-pressure sprays and simulated engine performance and emissions.

关键词： breakup model diesel engine high-pressure injection simulations

Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第01期 101-122页

作者： M.GHOLAMI M.EFTEKHARI department of mechanical engineering Shahid Bahonar University of Kerman

This study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGM) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. The nonlinear governing equations for the FGM pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. Through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGM composition. The examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. This comprehensive analysis enhances the understanding of nonlinear behaviors in FGM porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

关键词：

Few-shot learning for screening 2D Ga2CoS4-x supported single-atom catalysts for hydrogen production

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第01期 665-673页

作者： Nabil Khossossi Poulumi Dey department of mechanical engineering (ME) Delft University of Technology

Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction（HER）,which faces challenges of slow kinetics and high *** electrocatalysts,particularly single-atom catalysts （SACs） on two-dimensional （2D） materials,are *** study presents a few-shot machine learning （ML） assisted high-throughput screening of 2D septuple-atomic-layer Ga2CoS4-xsupported SACs to predict HER catalytic ***,density functional theory （DFT）calculations showed that 2D Ga2CoS4is inactive for ***,defective Ga2CoS4-x（x=0–0.25）monolayers exhibit excellent HER activity due to surface sulfur vacancies （SVs）,with predicted overpotentials （0–60 mV） comparable to or lower than commercial Pt/C,which typically exhibits an overpotential of around 50 m V in the acidic electrolyte,when the concentration of surface SV is lower than 8.3%.SVs generate spin-polarized states near the Fermi level,making them effective HER *** demonstrate ML-accelerated HER overpotential predictions for all transition metal SACs on 2D *** DFT data from 18 SACs,an ML model with high prediction accuracy and reduced computation time was *** intrinsic descriptor linking SAC atomic properties to HER overpotential was *** study thus provides a framework for screening SACs on 2D materials,enhancing catalyst design.

关键词：

Nano Brazing of Pt-Ag Nanoparticles under Femtosecond Laser Irradiation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2013年第2期5卷 88-92页

作者： L.Liu H.Huang A.Hu G.Zou L.Quintino Y.Zhou department of mechanical engineering Tsinghua University department of mechanical & mechatronics engineering University of Waterloo Technical University of Lisbon

Nano brazing of Pt-Ag nanoparticles with nano Ag filler metal is reported in this letter, which presents an effective way to join nanoobjects by femtosecond laser irradiation. The nano brazed interface between Pt-Ag and Ag showed good lattice matching along(111)_(Ag) //(111)_(Ag-Pt). Lattice mismatch can hardly be observed at the interface between the filler metal and Pt-Ag nanoparticle, which is important for the joint strength and normally does not occur during joining. The very low mismatch also suggested that melting and solidification occurred during nano brazing by femtosecond laser. The role of Brownian motion on the nano joining process is also discussed in this paper.

关键词： Femtosecond laser Nanojoining Nanoparticles