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1 – 10 of over 1000
Article
Publication date: 16 August 2023

Yuan Liu, Chang Dong, Xianzhang Wang, Xiao Sang, Liran Ma, Xuefeng Xu and Yu Tian

The purpose of this study is to reveal the underlying mechanism in film formation of oil-in-water (O/W) emulsion.

Abstract

Purpose

The purpose of this study is to reveal the underlying mechanism in film formation of oil-in-water (O/W) emulsion.

Design/methodology/approach

This study focuses on the film forming characteristics of O/W emulsion between the surface of a steel ball and a glass disc coated with chromium. The lubricant film thicknesses of O/W emulsion with various mechanical stirring strength were discussed, which were observed by technique of relative optical interference intensity.

Findings

The authors directly observed the oil pool in the contact area, finding the size of oil pool was closely related to the film-forming ability of emulsion. Enrichment phenomenon occurs in oil pool, which was caused by phase inversion. Further investigations revealed that the emulsion is stable with strong stirring strength, resulting in a smaller oil pool size and worse film forming ability.

Originality/value

With the wide usage of O/W emulsion in both biological and industrial systems, the ability of emulsion film formation is considered as an important factor to evaluate the lubrication effectiveness.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0354/

Details

Industrial Lubrication and Tribology, vol. 75 no. 8
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 4 July 2016

Yingwen Yan, Yajun Wang, Yuanhao Deng and Jinghua Li

This paper aims to get an in-depth understanding of the fuel spray characteristics to further improve the emission performance of a lean premixed prevaporized (LPP) combustor with…

Abstract

Purpose

This paper aims to get an in-depth understanding of the fuel spray characteristics to further improve the emission performance of a lean premixed prevaporized (LPP) combustor with staged lean combustion.

Design/methodology/approach

In this paper, the fuel spray characteristics in the LPP combustor are experimentally studied by using particle image velocimetry (PIV), and raw data are processed by image-processing technologies for different inlet conditions. The effects of the fuel allocation and pilot atomizer position on fuel spray characteristics are investigated.

Findings

Experiment results show that when only the pilot atomizer is operated, the fuel spray characteristics is worsened by increasing fuel flow rate. The fuel spray fields generated by the pilot atomizer are better at the throat than that at the pilot swirler outlet; when the pilot atomizer and primary injector are operated at the same time with the same inlet fuel air ratio, the spray characteristics are improved by increasing the primary fuel flow rate and decreasing the pilot fuel flow rate. Meanwhile, fuel spray fields generated by the pilot atomizer are better at the throat than that at the pilot swirler outlet.

Practical implications

The present results are useful for further development of the LPP combustor.

Originality/value

An LPP combustor with staged lean combustion technology was proposed; to obtain fuel spray characteristics, image-processing program was compiled; the fuel spray characteristics in the LPP combustor were investigated, especially the effects of the fuel allocation and pilot atomizer position.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 88 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 1 January 1989

C. Lea

The success of vapour phase soldering for electronic assemblies has led to the availability of several heat transfer fluids for the purpose. This paper aims to demonstrate the…

Abstract

The success of vapour phase soldering for electronic assemblies has led to the availability of several heat transfer fluids for the purpose. This paper aims to demonstrate the significance of the differing properties of fluids, illustrated by measurements on the three most commonly used in the UK. These three, as well as any future fluids, can be judged in terms of (i) vapour temperature and its influence on soldering yields and materials properties; (ii) stability of soldering temperature with time; (iii) heat transfer efficiency; (iv) power requirements and thermal control; (v) rosin solubility and flux wash‐off; (vi) toxicity, especially under thermal stress; (vii) corrosivity and its dependence on process control; and (viii) consumption of fluid.

Details

Soldering & Surface Mount Technology, vol. 1 no. 1
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 31 October 2018

Hadiseh Karimaei, Seyed Mostafa Hosseinalipour and Ramin Ghorbani

To estimate mean droplet diameter (MDD) of a spray, three different numerical models were used in this paper. One of them is investigation of the surface instability of the liquid…

Abstract

Purpose

To estimate mean droplet diameter (MDD) of a spray, three different numerical models were used in this paper. One of them is investigation of the surface instability of the liquid sheet producing from an injector.

Design/methodology/approach

First, the linear instability (LI) analysis introduced by Ibrahim (2006) is implemented. Second, the improved (ILI) analysis already introduced by the present authors is used. ILI analysis is different from the prior analysis, so that the instability of hollow-cone liquid sheet with different cone angles is investigated rather than a cylindrical liquid sheet. It means that besides the tangential and axial movements, radial movements of the liquid sheet and gas streams have been considered in the governing equations. Beside LI theory as a momentum-based approach, a new model as a theoretical energy-based (TEB) model based on the energy conservation law is proposed in this paper.

Findings

Based on the energy-based approach, atomization occurs because of kinetic energy loss. The resulting formulation reveals that the MDD is inversely proportional to the atomization efficiency and liquid Weber number.

Research limitations/implications

The results of these three models are compared with the available experimental data. Prediction obtained by the proposed TEB model is in reasonable agreement with the result of experiment.

Practical implications

The results of these three models are compared with the available experimental data. Prediction of the proposed energy-based theoretical model is in very good agreement with experimental data.

Originality/value

Comparison between the results of new model, experimental data, other previous methods show that it can be used as a new simple and fast model to achieve good estimation of spray MDD.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 21 December 2022

Qianqian Cao, Lujuan Li, Hao You and Hao Liu

The contact behaviors of droplets on confined surfaces influence significantly their dynamics and morphological transition induced by the electric field. This paper aims to delve…

Abstract

Purpose

The contact behaviors of droplets on confined surfaces influence significantly their dynamics and morphological transition induced by the electric field. This paper aims to delve into the electric stress, electric field distribution, flow field and evolution of droplet neck to understand the underlying mechanisms.

Design/methodology/approach

Electrohydrodynamics of droplets in confined environment is numerically analyzed based on finite volume method (FVM) combining with volume-of-fluid (VOF) method for two-phase interface capturing. Numerical solutions are obtained through solving electrohydrodynamics model coupling fluid dynamics with electrostatics.

Findings

It was found that the droplet neck with high interfacial curvature undergoes different transition depending on the contact angle. At large domain height, the droplets on the surfaces with the contact angle of θ < 90° tend to break up into smaller droplets adhered on top and bottom surfaces. The detachment of droplets is identified when the contact angle is much greater than 90°. Notably, the droplets at θ = 90° exhibit asymmetrical shape evolution, but for other cases there is symmetrical shape of droplets during transition process. With decreasing the domain height, no obvious deformation through driving the contraction of the droplet neck is observed.

Originality/value

It remains unclear how the electric field parallel to the surfaces affects the shape transition and electrohydrodynamics of confined droplets when changing the contact angle. In this paper, the authors study the electrohydrodynamics of droplets in confined space when the electric field is exerted parallel to contact surfaces. In particular, the authors consider the effect of the surface wettability on the droplet deformation. The problem is solved through FVM combining with the VOF method to implement the capturing of two-phase interfaces. The results indicate that the electrohydrodynamic behaviors of droplets are sensitive to the contact properties of droplets on the surfaces, which has not been reported in previous works.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 18 November 2021

Liew Phing Pui, Ianne Kong, Roselina Karim, Yus Aniza Yusof, Chen Wai Wong and Hasanah Mohd Ghazali

The purpose of this research is to produce “cempedak” juice using enzyme aided-liquefaction by examining the effects of enzyme types (Pectinex® Ultra SP-L, Celluclast® 1.5 L and…

Abstract

Purpose

The purpose of this research is to produce “cempedak” juice using enzyme aided-liquefaction by examining the effects of enzyme types (Pectinex® Ultra SP-L, Celluclast® 1.5 L and Fungamyl® 800 L), enzyme concentrations (0–1.5% v/w), incubation time (0–2.5 h) and incubation temperature (35–60 °C) on juice yield and viscosity, total soluble solids and color of fruit puree.

Design/methodology/approach

Ripe “cempedak” pulp from CH28 fruit was first pureed in a blender and then homogenized with water at 1:2 ratio. The diluted puree was then liquefied with the enzymes separately to reduce its viscosity. Analyses such as juice yield, viscosity, total soluble solids and color of the liquefied “cempedak” puree were then carried out.

Findings

Results indicated that the optimized use of 1.2% (v/w) Celluclast® 1.5 L (Novozymes, Denmark), a cellulase preparation, at 45 °C and 1 h produced juice with the lowest viscosity (349.4 cP) and the highest juice yield (82.3% v/w). Liquefied “cempedak” juice was darker (with L* value of 51.17) and more yellowish (b* value of 38.88) compared to “cempedak” juice without liquefaction (control). When compared to untreated “cempedak” juice, the droplet size of “cempedak” juice obtained after liquefaction under optimized conditions was found to be lower, regardless of whether the juice was filtered (with a total reduction of 23% of droplet size) or not filtered (with a total reduction of 16% of droplet size). The results indicate the possibility of employing Celluclast® 1.5 L to produce “cempedak” juice that can be further processed such as for the production of “cempedak” fruit powder.

Originality/value

This paper provides information on the enzyme concentration, incubation time and temperature for liquefying “cempedak” pulp such that the liquefied material produced can be used as a base feed for spray-drying to produce “cempedak” fruit powder.

Details

British Food Journal, vol. 124 no. 10
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 6 September 2021

Lu Chen, Chenchen Xu, Mingfei Ma, Wen Wang, Liang Guo and Patrick Wong

The cleaning of food production equipment using cleaning detergents may contaminate the lubricant of the bearings, thereby reducing the bearing service life. The purpose of this…

Abstract

Purpose

The cleaning of food production equipment using cleaning detergents may contaminate the lubricant of the bearings, thereby reducing the bearing service life. The purpose of this paper is to investigate the cause and mechanism of such damage of bearings lubricated by cleaning detergent/water-in-oil emulsions.

Design/methodology/approach

The emulsion was prepared by adding a mixture of cleaning detergent and water in one base oil. A self-designed ball-on-disc optical interference test rig was applied to examine the effect of emulsion on lubrication and wear of bearing contacts under pure sliding conditions.

Findings

The emulsion reduced lubricating film thickness at a relatively low-sliding speed but only when the water concentration (20%) in emulsion was high. Water droplets were trapped around the ball-on-disc contact area under static conditions because of a high capillary force. The emulsion can induce damages on the soft surface in the startup mainly due to the presence of water around the contact.

Originality/value

The basic lubrication behaviour of water/oil emulsions containing cleaning detergent under pure sliding was experimental studied and the mechanism of bearing damage in food production equipment was investigated. Based on the study, the solution to avoid such damage was proposed.

Details

Industrial Lubrication and Tribology, vol. 73 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 May 1981

A further part of BS 1728 Method for analysis of aluminium and aluminium alloys has just been published by the British Standards Institution. The addition to the series is Part 25…

Abstract

A further part of BS 1728 Method for analysis of aluminium and aluminium alloys has just been published by the British Standards Institution. The addition to the series is Part 25 Titanium (spectrophotometric chromotropic acid method) which covers the determination of titanium in the range 0.005 to 0.30 per cent. It is identical in purpose and range of titanium content with Part 13 of the series, which has been rendered obsolete by analytical progress and withdrawn. Part 25 is identical with ISO 1118.

Details

Aircraft Engineering and Aerospace Technology, vol. 53 no. 5
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 25 October 2018

Hadi Miyanaji, Niknam Momenzadeh and Li Yang

This study aims to experimentally investigate the effect of the powder material characteristics on the qualities of the binder jetting additive manufacturing parts both before and…

1225

Abstract

Purpose

This study aims to experimentally investigate the effect of the powder material characteristics on the qualities of the binder jetting additive manufacturing parts both before and after post processing (sintering).

Design methodology/approach

Three different types of the 316L stainless steel powder feedstock with various mean particle sizes and size distributions were studied. The influence of the powder particle size distributions and pore sizes on the powder bed packing densities and on the dynamics of the binder droplet-powder bed interactions were characterized. In addition, the surface roughness and densities of these parts both in the green state and after sintering were studied.

Findings

The results revealed the significant role of the powder feedstock characteristics on the liquid binder/powder bed interaction and consequently on the dimensional accuracies of the green parts. It was observed that the parts printed with the smaller mean particle sizes resulted in better surface finish and higher final densities after sintering. Furthermore, the hardness of the sintered parts produced with smaller powder particles exhibited higher values compared to the parts fabricated with the larger particles. On the other hand, larger particle sizes are advantageous for various green part qualities including the dimensional accuracies, green part densities and surface roughness.

Originality/value

This study establishes more comprehensive correlations between the powder feedstock characteristics and various quality criteria of the printed binder jetting components in both green and sintered states. These correlation are of critical importance in choosing the optimal process parameters for a given material system.

Details

Rapid Prototyping Journal, vol. 25 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 3 August 2010

Daniel L. Cohen and Hod Lipson

New applications of solid freeform fabrication (SFF) are arising, such as functional rapid prototyping and in situ fabrication, which push SFF to its limits in terms of…

Abstract

Purpose

New applications of solid freeform fabrication (SFF) are arising, such as functional rapid prototyping and in situ fabrication, which push SFF to its limits in terms of geometrical fidelity due to the applications' inherent process uncertainties. Current closed‐loop feedback control schemes monitor and manipulate SFF techniques at the process level, e.g. envelope temperature, feed rate. “Closing the loop” on the process level, instead of the overall part geometry level, leads to limitations in the types of errors that can be detected and corrected. The purpose of this paper is to propose a technique called greedy geometric feedback (GGF) control which “closes the loop” on the overall part geometry level.

Design/methodology/approach

The overall part geometry is monitored throughout the print and, using a greedy algorithm, real‐time decisions are made to serially determine the locations of subsequent droplets, i.e. overall part geometry is directly manipulated. A computer simulator and a physical experimental platform were developed to compare the performance of GGF to an open‐loop control scheme. Root mean square surface height errors were measured under controlled uncertainties in droplet height, droplet radius of curvature, droplet positioning and mid‐print part deformations.

Findings

The GGF technique outperformed open‐loop control under process uncertainties in droplet shape, droplet placement and mid‐print part deformations. The disparity between performances is dependant on the nature and extent of the imposed process uncertainties.

Practical implications

Future research will focus on improving the performance of GGF for specific cases by designing more complex greedy algorithmic scoring heuristics. Also, the technique will be generalized beyond heightmap representations of 3D spaces.

Originality/value

The GGF technique is the first to “close the loop” on the overall part geometry level. GGF, therefore, can compensate for a broader range of errors than existing closed‐loop feedback control schemes. Also, since the technique only requires the real‐time update of a very limited set of heights, the technique is computationally inexpensive and widely applicable. By developing a closed‐loop feedback scheme that addressed part geometry‐level errors, SFF can be applied to more challenging in situ fabrication scenarios with less conventional materials.

Details

Rapid Prototyping Journal, vol. 16 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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