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Article
Publication date: 9 April 2019

Zhenpeng Wu, Xianzhong Ding, Liangcai Zeng, Xiaolan Chen and Kuisheng Chen

This paper aims to use the method of curve splicing to combine the slip zone and the no-slip zone to further improve the lubrication performance of the liquid film. The…

Abstract

Purpose

This paper aims to use the method of curve splicing to combine the slip zone and the no-slip zone to further improve the lubrication performance of the liquid film. The combination of the slip zone and the no-slip zone of an existing heterogeneous surface is still a single line stitching method so that a very large residual space at the surface of the friction pairs remains present, necessitating further improvement of the joining scheme between the slip zone and the no-slip zone in heterogeneous surfaces.

Design/methodology/approach

A set of discrete sinusoids is used as the splicing track for both the slip zone and the no-slip zone, the starting point and amplitude of the curve are introduced as the simulation variables and the effects of these variables on the bearing capacity and friction coefficient of the liquid film are comprehensively analyzed.

Findings

The results show that the method of selecting the sinusoidal curve as the slip zone and the no-slip zone trajectory, which is based on the existing method of linear stitching, can further enhance the bearing capacity and reduce the friction coefficient of the liquid film.

Originality/value

This method can further enhance the bearing capacity and reduce the friction coefficient of the liquid film.

Details

Industrial Lubrication and Tribology, vol. 71 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 November 2021

Yi Liu, Guangyao Qiu, Tao Li, Ang Yan, Yongfeng Liu, Rongjun Qu and Changmei Sun

To treat water pollution, especially the contamination resulted from organic dyes has aroused significant attention around the world, this study aims to prepare the metal organic…

Abstract

Purpose

To treat water pollution, especially the contamination resulted from organic dyes has aroused significant attention around the world, this study aims to prepare the metal organic framework (MOF) materials hybridizing with poly(p-phenylene terephthalamide) (PPTA) by means of a facile refluxing method and to systematically investigate adsorption performance for anionic dye Congo red as target molecule from aqueous solution.

Design/methodology/approach

The MOF materials hybridized by PPTA were fabricated by virtue of a facile refluxing method, characterized by thermogravimetric analysis, X-ray powder diffraction, Fourier transform infrared and pore structure.

Findings

The results showed that pseudo-second-order kinetic model could better describe the adsorption process for all the four materials, whereas Elovich model also fitted the process for the hybrid materials with PPTA. Adsorption isotherm analyses indicated that Langmuir isotherm could be used to describe the adsorption process. Introduction of appropriate amount of PPTA could enhance the adsorption affinity of the MOF materials for Congo red, and the maximum adsorption capacity could reach as high as 1,053.41 mg/g while that of the MOF material without PPTA was 666.67 mg/g, indicating introduction of PPTA could change the microenvironment of the MOF materials and increase the adsorption sites, leading to high adsorption efficiency.

Research limitations/implications

The microstructure of MOF hybridized materials in detail is the further and future investigation.

Practical implications

This study will provide a method to prepare MOF materials with high efficiency to treat anionic dyes like Congo red from aqueous solution.

Originality/value

Owing to the special characteristics of PPTA and similar to carbon tube, PPTA was introduced into MOF material to increased corresponding water stability. Because of aromatic ring and amide group on the surface of PPTA, the adsorption efficiency of the hybridized MOF material with appropriate amount of PPTA was greatly enhanced.

Details

Pigment & Resin Technology, vol. 52 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 3 September 2019

Xin Wang, Bo Xu and Z. Chen

This paper aims to investigate spontaneous movement of single droplet on chemically heterogeneous surfaces induced by the net surface tension, using the improved three-dimensional…

Abstract

Purpose

This paper aims to investigate spontaneous movement of single droplet on chemically heterogeneous surfaces induced by the net surface tension, using the improved three-dimensional (3D) lattice Boltzmann (LB) method.

Design/methodology/approach

D3Q19 Shan-Chen LB model is improved in this paper. Segmented particle distribution functions coupled with the P-R equation of state are introduced to maintain the higher accuracy and greater stability. In addition, exact difference method (EDM) is adopted to implement force term to predict the droplet deformation and dynamics.

Findings

The numerical results demonstrate that spontaneous movement of single droplet (=1.8 µm) along wedge-shaped tracks is driven by net surface tension. Advancing angle decreases instantaneously with time, while receding angle changes slightly first and then decreases rapidly. Wetting length is affected by vertex angle and wetting difference, whereas the final value is only dependent on the stronger wettability. Although the velocity of single droplet on wedge-shaped tracks can be increased by the larger vertex angle, it has a negative influence on the displacement. For the same wetting difference, vertex angle equal to 30º is an optimization strategy in this model. If the simulation length is extended enough, then the smaller vertex angle is beneficial for the droplet movement. In addition, a larger wetting difference is beneficial to spontaneous movement, which can speed up the droplet movement.

Originality/value

The proposed numerical model of droplet dynamics on chemically heterogeneous surfaces provides fundamental insights for the enhancement of drop-wise condensation heat transfer.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 27 December 2022

Ge Li, Qiushi Kang, Fanfan Niu and Chenxi Wang

Bumpless Cu/SiO2 hybrid bonding, which this paper aims to, is a key technology of three-dimensional (3D) high-density integration to promote the integrated circuits industry’s…

Abstract

Purpose

Bumpless Cu/SiO2 hybrid bonding, which this paper aims to, is a key technology of three-dimensional (3D) high-density integration to promote the integrated circuits industry’s continuous development, which achieves the stacks of chips vertically connected via through-silicon via. Surface-activated bonding (SAB) and thermal-compression bonding (TCB) are used, but both have some shortcomings. The SAB method is overdemanding in the bonding environment, and the TCB method requires a high temperature to remove copper oxide from surfaces, which increases the thermal budget and grossly damages the fine-pitch device.

Design/methodology/approach

In this review, methods to prevent and remove copper oxidation in the whole bonding process for a lower bonding temperature, such as wet treatment, plasma surface activation, nanotwinned copper and the metal passivation layer, are investigated.

Findings

The cooperative bonding method combining wet treatment and plasma activation shows outstanding technological superiority without the high cost and additional necessity of copper passivation in manufacture. Cu/SiO2 hybrid bonding has great potential to effectively enhance the integration density in future 3D packaging for artificial intelligence, the internet of things and other high-density chips.

Originality/value

To achieve heterogeneous bonding at a lower temperature, the SAB method, chemical treatment and the plasma-assisted bonding method (based on TCB) are used, and surface-enhanced measurements such as nanotwinned copper and the metal passivation layer are also applied to prevent surface copper oxide.

Details

Microelectronics International, vol. 40 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 December 2004

Wei Sun, Tao Jiang and Feng Lin

A processing algorithm for freeform fabrication of heterogeneous structures is presented. The algorithm was developed based on the heterogeneous fabrication structural model…

Abstract

A processing algorithm for freeform fabrication of heterogeneous structures is presented. The algorithm was developed based on the heterogeneous fabrication structural model, which was constructed from the STL based multi‐material volume regions and with material identifications. The reasoning Boolean operation based modelling approach was used to construct the heterogeneous CAD assembly and to output the needed STL format. Procedures for generating the database hierarchy and the storage of the heterogeneous structural model, and derivation for developing the processing algorithm for layered fabrication of heterogeneous structure are presented. The developed algorithm was applied to a heterogeneous structure consisting of two discrete material volumes, and the detailed processing path is described.

Details

Rapid Prototyping Journal, vol. 10 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 3 December 2018

Patcharaporn Chuayplod and Duangdao Aht-Ong

The purpose of this work was to modify the surface of parawood sawdust (Hevea brasiliensis) microcrystalline cellulose (PW-MCC) used as reinforcing agent in polypropylene…

Abstract

Purpose

The purpose of this work was to modify the surface of parawood sawdust (Hevea brasiliensis) microcrystalline cellulose (PW-MCC) used as reinforcing agent in polypropylene composites with benzoyl chloride under a mechanochemistry process.

Design/methodology/approach

The acetylated PW-MCC was produced from heterogeneous condition using planetary ball mill process at a rotation speed of 400 rpm. Before the esterification reaction, PW-MCC was pre-treated with pyridine at 60°C for 1 h in order to penetrate and swell the cellulose structure. The optimum condition of esterified PW-MCC with various molar ratios of benzoyl chloride/anhydroglucose unit (AGU) was studied. The degree of substitution, functional group, thermal stability and morphology of esterified cellulose were characterized by 1H-nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA) and scanning electron microscopy (SEM).

Findings

The functional group from FTIR confirmed that PW-MCC was successfully esterified with benzoyl chloride. The optimum condition which gave the maximum degree of substitution at 3.00 was achieved by using benzoyl chloride/AGU at 5 for 1 h. SEM analysis revealed that the modified PW-MCC surface became rougher than the unmodified PW-MCC surface. The polypropylene composites with 5-30 wt% PW-MCC and esterified PW-MCC were prepared without compatibilizer.

Originality/value

The composites with esterified PW-MCC enhanced water resistance and thermal stability when compared to composites with PW-MCC.

Details

World Journal of Engineering, vol. 15 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 8 June 2021

Najiyah Safwa Khashi'ie, Norihan Md Arifin, Natalia C. Rosca, Alin V. Rosca and Ioan Pop

The purpose of this paper is to study the effects of thermal radiation and homogeneous-heterogeneous reactions in the three-dimensional hybrid nanofluid flow past a permeable…

Abstract

Purpose

The purpose of this paper is to study the effects of thermal radiation and homogeneous-heterogeneous reactions in the three-dimensional hybrid nanofluid flow past a permeable stretching/shrinking sheet.

Design/methodology/approach

The combination of aluminum oxide (Al2O3) and copper (Cu) nanoparticles with total volumetric concentration is numerically analyzed using the existing correlations of hybrid nanofluid. With the consideration that both homogeneous and heterogeneous reactions are isothermal while the diffusion coefficients of both autocatalyst and reactant are same, the governing model is simplified into a set of differential (similarity) equations.

Findings

Using the bvp4c solver, dual solutions are presented, and the stability analysis certifies the physical/real solution. The findings show that the suction parameter is requisite to induce the steady solution for shrinking parameter. Besides, the fluid concentration owing to the shrinking sheet is diminished with the addition of surface reaction.

Originality/value

The present findings are novel and can be a reference point to other researchers to further analyze the heat transfer performance and stability of the working fluids.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 August 2015

Deniz D. Somer, D Peric, Eduardo Alberto de Souza Neto and Wulf G Dettmer

The purpose of this paper is to present knowledge in estimating yield surfaces of heterogeneous media by use of homogenization, especially where the macroscopic behaviour is…

Abstract

Purpose

The purpose of this paper is to present knowledge in estimating yield surfaces of heterogeneous media by use of homogenization, especially where the macroscopic behaviour is driven by weak interfaces between phase constituents.

Design/methodology/approach

A computational homogenization procedure is used to determine the yield surface of a Representative Volume Element (RVE) that contains a fully debonded inclusion embedded within ideally plastic matrix, whereby the interface is modelled by a Coulomb type friction law.

Findings

The macroscopic behaviour of the RVE is shown to coincide an RVE with a hole for expanding loads, whereas for compressive loads, it was shown to approach an RVE with a fully bonded inclusion.

Originality/value

The present paper builds on Gurson’s work in estimating macroscopic yield surfaces of heterogeneous materials. The work is novel in the sense that there had been no previous publications discussing influence of weak interfaces on yield surfaces.

Details

Engineering Computations, vol. 32 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 30 May 2020

R. Meenakumari, P. Lakshminarayana and K. Vajravelu

The aim of the present paper is to investigate the homogeneous and heterogeneous reactions on Prandtl fluid flow at a stretching sheet with an induced magnetic field and slip…

Abstract

Purpose

The aim of the present paper is to investigate the homogeneous and heterogeneous reactions on Prandtl fluid flow at a stretching sheet with an induced magnetic field and slip boundary conditions.

Design/methodology/approach

The governing equations include the continuity, induced magnetic field, momentum, energy and homogeneous–heterogeneous equations. Initially, with suitable similarity variables, the governing partial differential equations and converted into a system of ordinary differential equations. Then, the nonlinear ordinary differential equations are solved by a shooting technique with the help of the BVC5C Matlab package.

Findings

The results of the present investigation are presented through graphs for different values of the various parameters. The authors observed that the large values of the stretching ratio and the induced magnetic parameters are moderate magnetic field, velocity and temperature primarily. Also, the authors found the more velocity and temperatures by boosting the slip parameters.

Originality/value

In addition, the values of the skin friction and the rate of heat transfer for various values of physical parameters are tabulated and deliberated in detail.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 23 November 2018

Subrata Das, Hiranmoy Mondal, Prabir Kumar Kundu and Precious Sibanda

The focus of the paper is only on the contributions toward the use of entropy generation of non-Newtonian Casson fluid over an exponential stretching sheet. The purpose of this…

Abstract

Purpose

The focus of the paper is only on the contributions toward the use of entropy generation of non-Newtonian Casson fluid over an exponential stretching sheet. The purpose of this paper is to investigate the entropy generation and homogeneous–heterogeneous reaction. Velocity and thermal slips are considered instead of no-slip conditions at the boundary.

Design/methodology/approach

Basic equations in form of partial differential equations are converted into a system of ordinary differential equations and then solved using the spectral quasi-linearization method (SQLM).

Findings

The validity of the model is established using error analysis. Variation of the velocity, temperature, concentration profiles and entropy generation against some of the governing parameters are presented graphically. It is to be noted that the increase in entropy generation due to increase in heterogeneous reaction parameter is due to the increase in heat transfer irreversibility. It is further noted that the Bejan number decreases with Brinkman number because increase in Brinkman number reduces the total entropy generation.

Originality/value

This paper acquires realistic numerical explanations for rapidly convergent temperature and concentration profiles using the SQLM. Convergence of the numerical solutions was monitored using the residual error of the PDEs. The resulting equations are then integrated using the SQLM. The influence of emergent flow, heat and mass transfer parameters effects are shown graphically.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

1 – 10 of over 4000