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Article
Publication date: 24 April 2007

Dominique Boursillon and Volker Riethmüller

This study aims to compare the aptitude of pine as a softwood and beech as a hardwood, regarding their different retention and antimicrobial performances as compared to…

Abstract

Purpose

This study aims to compare the aptitude of pine as a softwood and beech as a hardwood, regarding their different retention and antimicrobial performances as compared to polyethylene.

Design/methodology/approach

Four sets of tests were carried out: recovery, cleaning, remobilization and survival experiments. For all experiments wood and control blocks or chippings were spiked with bacteria and tested at set intervals for bacterial counts using standard procedures.

Findings

Overall, wood performed at least as good as polyethylene. Polyethylene is not as easy to clean. The problematic cleansing capabilities of wood are compensated by its open structure. Pine exerted antimicrobial abilities faster than beech and showed better performance than both beech and polyethylene. The differences between beech and polyethylene were only marginal.

Research limitations/implications

The findings may help along with further research to re‐establish the value of wood in some food processing settings and in the home. However, only new materials were used so that no statement on the performance of used wood and plastic utensils can be made. Besides, only two types of woods and one type of plastic were used in this study.

Originality/value

This article is written with the expertise of the authors and will be of interest to those in the field.

Details

British Food Journal, vol. 109 no. 4
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 29 August 2019

Danna Tang, Liang Hao, Yan Li and Zheng Li

The study aims to explore the composition and microstructure of clay functionally graded materials under the process of double-gradient direct ink writing (DIW).

Abstract

Purpose

The study aims to explore the composition and microstructure of clay functionally graded materials under the process of double-gradient direct ink writing (DIW).

Design/methodology/approach

The investigation focused specifically on the pore characteristics of barite-kaolin clay composite after three-dimensional (3D) printing and sintering as well as its bionic application in geophysical model.

Findings

The model with pore and material variations brought about spatial and nonlinear mechanical properties. Moreover, the vertical gradient and connected pores in the upper kaolin part simulated the natural phenomenon of the landslide model (take Chinese Majiagou landslides as an example). Both the thermal debinding behavior and the kaolin powder particles characteristics [large pore volume (0.019 cm3g1) and pore size (29.20 nm)] were attributed to the interconnection channels.

Originality/value

Hence, the macroscopic and microscopic pores achieved by dual-gradient DIW process make it possible to control the permeability and details of properties, precisely in the geological model.

Details

Rapid Prototyping Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 7 August 2017

Ji Youjun and K. Vafai

The purpose of this study is to digitize the porous structure and reconstruct the geometry of the rock by using the image processing software photoshop (PS) and ant colony…

Abstract

Purpose

The purpose of this study is to digitize the porous structure and reconstruct the geometry of the rock by using the image processing software photoshop (PS) and ant colony algorithm coded with compiler Fortran PowerStation (fps) 4.0 based on the microscopic image of a typical rock mass.

Design/methodology/approach

The digital model of the microstructure of the porous coal rock was obtained, and imported into the numerical simulation software to build the finite element model of microstructure of the porous coal rock. Creeping flow equations were used to describe the fluid flow in the porous rock.

Findings

The simulation results indicate that the method utilized for reconstructing the microstructure of the porous coal rock proposed in this work is effective. The results demonstrate that the transport of fluid in a porous medium is significantly influenced by the geometric structure of the pore and that the heterogeneous porous structure would result in an irregular flow of the fluid.

Research limitations/implications

The authors did not experience a limitation.

Practical implications

The existence of the pores with dead ends would hinder the fluid to flow through the coal rock and reduce the efficiency of extracting fluid from the porous coal rock. It is also shown that the fluid first enters the large pores and subsequently into the small pore spaces.

Social implications

The paper provides important and useful results for several industries.

Originality value

Image processing technology has been utilized to incorporate the micro image of the porous coal rock mass, based on the characteristics of pixels of the micro image. The ant colony algorithm was used to map out the boundary of the rock matrix and the pore space. A FORTRAN code was prepared to read the micro image, to transform the bmp image into a binary format, which contains only two values. The digital image was obtained after analyzing the image features. The geometric structure of the coal rock pore was then constructed. The flow process for the micro fluid in the pore structure was illustrated and the physical process of the pore scale fluid migration in the porous coal seam was analyzed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 8 October 2020

Yijiang Peng, Zhenghao Wu, Liping Ying and Desi Yang

This paper aims to propose the five-phase sphere equivalent model of recycled concrete, which can be used to deduce the theoretical formulas for the Poisson’s ratio and…

Abstract

Purpose

This paper aims to propose the five-phase sphere equivalent model of recycled concrete, which can be used to deduce the theoretical formulas for the Poisson’s ratio and effective elastic modulus.

Design/methodology/approach

At a mesoscopic level, the equivalent model converts the interfacial layer, which consists of the new interfacial transition zone (ITZ), the old mortar and the old (ITZ), into a uniform equivalent medium. This paper deduces a strength expression for the interfacial transition zone at the microscopic level using the equivalent model and elastic theory. In addition, a new finite element method called the base force element method was used in this research.

Findings

Through numerical simulation, it was found that the mechanical property results from the five-phase sphere equivalent model were in good agreement with those of the random aggregate model. Furthermore, the proposed model agree on quite well with the available experimental data.

Originality/value

The equivalent model can eliminate the influence of the interfacial layer on the macroscopic mechanical properties, thereby improving the calculation accuracy and computational efficiency. The proposed model can also provide a suitable model for multi-scale calculations.

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Article
Publication date: 1 July 1968

C.W. Tuck

Certain previously unobserved features of scale formed in an oil‐fired billet reheating furnace are described. It is shown that sulphur‐rich melts formed at the…

Abstract

Certain previously unobserved features of scale formed in an oil‐fired billet reheating furnace are described. It is shown that sulphur‐rich melts formed at the scale/metal interface penetrate the grain boundaries of the overlying scale: subsequently the sulphur is removed by an oxidation reaction in which the surrounding manganese‐containing oxide takes part, to form a complex manganese silicate. The thermodynamics of possible reactions are discussed briefly and hypotheses put forward for the transport mechanisms of sulphur from the furnace atmosphere to the scale/metal interface.

Details

Anti-Corrosion Methods and Materials, vol. 15 no. 7
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 19 September 2008

C.J. Visser, A.G. Malan and J.P. Meyer

The purpose of this paper is to focus on modeling buoyancy driven viscous flow and heat transfer through saturated packed pebble‐beds via a set of homogeneous…

Abstract

Purpose

The purpose of this paper is to focus on modeling buoyancy driven viscous flow and heat transfer through saturated packed pebble‐beds via a set of homogeneous volume‐averaged conservation equations in which local thermal disequilibrium is accounted for.

Design/methodology/approach

The local thermal disequilibrium accounted for refers to the solid and liquid phases differing in temperature in a volume‐averaged sense, which is modeled by describing each phase with its own governing equation. The partial differential equations are discretized and solved via a vertex‐centered edge‐based dual‐mesh finite volume algorithm. A compact stencil is used for viscous terms, as this offers improved accuracy compared to the standard finite volume formulation. A locally preconditioned artificial compressibility solution strategy is employed to deal with pressure incompressibility, whilst stabilisation is achieved via a scalar‐valued artificial dissipation scheme.

Findings

The developed technology is demonstrated via the solution of natural convective flow inside a heated porous axisymmetric cavity. Predicted results were in general within 10 per cent of experimental measurements.

Originality/value

This is the first instance in which both artificial compressibility and artificial dissipation is employed to model flow through saturated porous materials.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 18 no. 7/8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 June 2000

Lijun Qiao, Allan J. Easteal, Clive J. Bolt, Philip K. Coveny and Robert A. Franich

Four different approaches were taken to improve the water resistance of poly(vinyl acetate) (PVAc) emulsion adhesives. The improved wood adhesives were tested according to…

Abstract

Four different approaches were taken to improve the water resistance of poly(vinyl acetate) (PVAc) emulsion adhesives. The improved wood adhesives were tested according to the ISO 9020 standard. Tensile storage modulus (E’) and glass transition temperature of the polymer films were measured using dynamic mechanical thermal analysis to quantify the influence of different approaches on those variables. Gel fraction and swelling ratio of the polymer film were measured to evaluate internal crosslink density. The experimental results showed that blending melamine/urea/formaldehyde (MUF) resin with PVAc emulsions modified the water resistance considerably and the film had a high E’ since an interpenetrating network‐type structure was formed in the polymer. The advantages and limitations of each modification were assessed on the basis of comparison of the results.

Details

Pigment & Resin Technology, vol. 29 no. 3
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 6 November 2017

A.U. Chaudhry, Vikas Mittal, M.I. Hashmi and Brajendra Mishra

Inorganic oxide addition can be synergistically beneficial in organic coatings if it can impart anti-corrosion properties and also act as an additive to enhance physical…

Abstract

Purpose

Inorganic oxide addition can be synergistically beneficial in organic coatings if it can impart anti-corrosion properties and also act as an additive to enhance physical and/or chemical properties. The aim of this study was to evaluate the anti-corrosion benefits of nano nickel zinc ferrite (NZF) in the polymer film.

Design/methodology/approach

The time-dependent anti-corrosion ability of NZF (0.12-1.0 per cent w/w NZF/binder), applied on API 5L X-80 carbon steel, was characterized by electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic. Characterization of corrosion layer was done by removing coatings after 216 h of immersion in 3.5 per cent w/v NaCl. Optical microscopy, field emission scanning electron microscopy and X-ray diffraction techniques were used to characterize the corroded surface.

Findings

Corrosion measurements confirm the electrochemical activity by metallic cations on the steel surface during corrosion process which results in improvement of anti-corrosion properties of steel. Moreover, surface techniques show compact corrosion layer coatings and presence of different metallic oxide phases for nanocomposite coatings.

Originality/value

The suggested protection mechanism was explained by the leaching and precipitation of metallic ion on the corroded surface which in turn slowed down the corrosion activity. Furthermore, improvement in barrier properties of rubber-based coatings was confirmed by the enhanced pore resistance. This work indicates that along with a wide range of applications of NZF, anti-corrosion properties can be taken as an addition.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 20 August 2019

Hai Tan, Deguo Wang and Yanbao Guo

Abundant oil and gas reservoirs in the deep-water are the valuable non-renewable energy sources. However, sea-water could enhance the corrosion of marine equipment such as…

Abstract

Purpose

Abundant oil and gas reservoirs in the deep-water are the valuable non-renewable energy sources. However, sea-water could enhance the corrosion of marine equipment such as submarine pipe trees. Various coatings, for example, polyurethane (PU) coatings are sprayed on the steel surfaces to enhance the anti-corrosion performance. Thus, to improve the anti-corrosion behavior of PU coatings in sea-water is imperative.

Design/methodology/approach

In this paper, the corrosion behaviors of 4130 carbon steel with and without PU coatings were discussed by electrochemical mean in sea-water. And the graphene additive in different concentrations (0.1, 0.3, 0.6 and 0.9 per cent) were also studied. A series of characterized methods were introduced to identify the anti-corrosion performances of 4130 carbon steel with and without coatings, respectively.

Findings

The results showed that the anti-corrosion property of 4130 carbon steel can enhance obviously with the PU coatings. The graphene additive can further improve the anti-corrosion behaviour of PU coatings and in the concentration of 0.6 per cent the PU/graphene coatings worked best.

Originality/value

This is beneficial for enhancing the service life of marine equipment in an eco-friendly method.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 April 1995

A. Chatterjee and K. Muralidhar

The analysis of enhanced oil recovery using surfactants is presentedhere. Surfactants lower the surface tension between oil and water and hencethe capillary resistance to…

Abstract

The analysis of enhanced oil recovery using surfactants is presented here. Surfactants lower the surface tension between oil and water and hence the capillary resistance to flow. The mathematical description of this problem requires modelling of multi‐phase flow in a porous medium. A pressure‐based formulation has been used in the present study. The governing partial differential equations have been solved by a finite difference method. Both Newtonian and non‐Newtonian (shear thinning) behaviour of oil are considered. Results clearly show an improvement in oil recovery in the presence of surfactants. A study of the ideal case where surface tension is reduced to zero shows that oil recovery can be very high.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 5 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

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