Search results

1 – 10 of 76
Article
Publication date: 1 February 2001

Sven Berg

The wear of a machine element, whether it is due to fatigue or abrasive wear, will add contaminants in the form of particulates to the system. If a machine element is…

Abstract

The wear of a machine element, whether it is due to fatigue or abrasive wear, will add contaminants in the form of particulates to the system. If a machine element is starting to wear out it will produce a large amount of particles and it will finally break down. Since this can be very costly, one can establish the need to monitor the system so that one can foresee failure. There are many different ways to monitor a system, e.g. measurements of the temperature, pressure, vibrations and the degree of contamination. The purpose of contamination control is to extend the life of a component and thereby save money. When monitoring a system it is very important that the monitoring control instrument should give the right output. One important factor in achieving this is the withdrawal of a representative oil sample. In this paper an investigation of where and how to take a representative sample is performed using Stokes’ law and the migration of spheres in a channel. A generalised sedimentation chart for different oils and particles is introduced. Sampling routines for proper sample withdrawal are also presented.

Details

Industrial Lubrication and Tribology, vol. 53 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 2 April 2019

Nda Muhammad, Mohd Shalahuddin Adnan, Mohd Azlan Mohd Yosuff and Kabiru Abdullahi Ahmad

Sediment measurement is usually accessible on a periodic or distinct basis. The measurement of sediment (suspended and bedload), especially in the field, is vital in…

Abstract

Purpose

Sediment measurement is usually accessible on a periodic or distinct basis. The measurement of sediment (suspended and bedload), especially in the field, is vital in keeping essential data of sediment transport and deposition. Various techniques for measuring sediment have been used over time each with its merits and demerits. The techniques discussed in this paper for suspended sediment include bottle, acoustic, pump, laser diffraction, nuclear and optical. Other techniques for bedload measurement are; River bedload trap (RBT), CSU/FU bedload trap, Helley–Smith, Polish Hydrological Services (PIHM) device, pit and trough, vortex tube, radioactive traces and bedload–surrogate technologies. However, the choice of technique depends on multiple factors ranging from budget constraint, availability of equipment, manpower and data requirement. The purpose of this paper is to present valuable information on selected techniques used in sediment measurement, to aid researchers/practitioners in the choice of sediment measurement technique.

Design/methodology/approach

This paper presents a general review of selected field techniques used in sediment measurement (suspended and bedload). Each techniques mode of operation, merits and demerits are discussed.

Findings

This paper highlights that each technique has its peculiar merits and demerits. However, two techniques are generally preferred over others; the bottle sampling and the Helley–Smith sampler for measuring suspended and bedload sediment. This is because the applicability of these techniques is quite widespread and time-tested.

Originality/value

This review paper provides an in-depth description and comparison of selected existing field sediment measurement techniques. The objective is to ease decision-making about the choice of technique, as well as to identify the suitability and applicability of the chosen technique.

Details

World Journal of Engineering, vol. 16 no. 1
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 27 September 2011

Sven Berg, Ulf Jungmar, Jan Lundberg and Pekka Vähäoja

The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV‐values, when measuring samples of fully…

Abstract

Purpose

The aim of this study is to determine the variation of the different oil analysis instruments in terms of standard deviation and CV‐values, when measuring samples of fully formulated hydraulic and gear oils taken from working systems.

Design/methodology/approach

In this investigation, two different spectrometric techniques, inductively coupled plasma‐optical emission spectrometers (ICP‐OES) and rotating disk electrode‐optical emission spectrometers (RDE‐OES), have been studied to determine the instruments' precision of measurement and ability to measure the absolute level of contamination. The study was based on a series of measurements using artificial contamination mixed with oil.

Findings

The ICP has better precision of measurement of the two instruments, but cannot predict the absolute values of contamination when oil samples are only treated by organic solvent dilution if the samples include large or dense particles. It is therefore not too good, with the sample pre‐treatment method used, at detecting wear processes that produce dense/large particles, such as pitting failure. For instance, microwave‐assisted acid digestion could be used for sample pre‐treating to obtain accurate results in that case. It should, however, be able to detect wear mechanisms that produce small particles such as abrasive wear in any case. The ICP has a repeatability value of r=3 percent and a reproducibility value of R=12 percent for contamination levels of between 50 and 400 ppm and r=0.6  and R=2 ppm, respectively, at values below 50 ppm. The RDE cannot predict the absolute value of contamination if this includes large or dense particles if proper sample pre‐treatment is not used. It is therefore not good at detecting wear mechanisms that produces dense/large particles (if the oil samples are not pre‐treated properly) such as pitting but should be able to detect abrasive wear and similar processes that produce small particles in any case. The RDE's precision of measurement is not as good as the ICP, with a reproducibility variation of R=r=25 percent for contamination levels between 20 and 500 ppm and R=r=6 ppm for contamination level below 20 ppm.

Research limitations/implications

Only the effects from lubricating oils are studied.

Practical implications

This study will significantly increase the industrial knowledge concerning measurement precision in particle contamination measurement systems.

Originality/value

No similar study is found.

Details

Industrial Lubrication and Tribology, vol. 63 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 September 2006

Teofil Jesionowski

Proposes to investigate preparation of amorphous silica via precipitation reaction from aqueous solution of sodium metasilicate and hydrochloric acid in emulsion medium…

2310

Abstract

Purpose

Proposes to investigate preparation of amorphous silica via precipitation reaction from aqueous solution of sodium metasilicate and hydrochloric acid in emulsion medium, focusing on determination to optimise the dispersive and morphological properties of silicas studied.

Design/methodology/approach

The silicas obtained were analysed using modern research techniques, such as scanning electron microscopy for studies on particle surface morphology and dynamic light scattering technique for studies on particle structure and their tendency for agglomeration. Moreover, the sedimentation characteristics of the silica powders were evaluated.

Findings

The properties of silicas precipitated from emulsion systems depend on several variables but the amount and concentration of the applied reagents and pH of the emulsion are of critical importance. Using 16, 14 or 12 wt% solution of sodium metasilicate (per SiO2 content) and 5.0, 4.3 or 3.7 wt% solution of hydrochloric acid, the particles obtained were of best dispersive parameters. Mean diameter, polydispersity, shape and sedimentation of particles reflect the applied preparation procedure. Several of the silicas obtained manifest tendency for formation of secondary agglomerates and aggregates. The pH of the solution obtained from two mixed emulsions exerts a pronounced influence on quality and properties of the prepared silica. The best silica is obtained at pH 6‐7. In the cases where the emulsion has been dosed with “pure” sodium metasilicate solution, particles of irregular shape of high mean particle diameters, with a tendency to form large particle accumulations, have been formed.

Research limitations/implications

In the precipitation reaction, aqueous solution of sodium metasilicate, hydrochloric acid and emulsifiers in the form of non‐ionic surfactants were used as substrates. The organic phase involved cyclohexane. Alternatives could be explored.

Practical implications

The method developed provides a novel and practical solution to precipitation of hydrophilic/hydrophobic silica fillers.

Originality/value

The method for obtaining amorphous types of silica could find numerous applications, particularly as polymer fillers.

Details

Pigment & Resin Technology, vol. 35 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 29 June 2012

A. Laurentowska, F. Ciesielczyk, K. Siwińska‐Stefańska and T. Jesionowski

The purpose of this paper is to obtain ZnO‐SiO2 oxide composites of low bulk density, high homogeneity and consisting of the smallest possible particles. The optimum…

Abstract

Purpose

The purpose of this paper is to obtain ZnO‐SiO2 oxide composites of low bulk density, high homogeneity and consisting of the smallest possible particles. The optimum parameters of precipitation of ZnO‐SiO2 oxide composites impregnated with natural latex rubber were established. The formation and impregnation the ZnO‐SiO2 oxide composites were made to occur simultaneously.

Design/methodology/approach

The influence of non‐ionic surfactants added during the precipitation process on the physico‐chemical properties of the oxide systems obtained was investigated. The products were characterised by determination of bulk density, absorption capacities of water and paraffin oil, particle size distribution (applying NIBS and laser diffraction methods), as well as SEM observations of surface morphology and microstructure. Moreover, the colorimetric characteristics of the oxide composites obtained and sedimentation profiles in water were analysed. Energo‐dispersive microanalysis of the products enabled determination of the content of ZnO and SiO2. The surface area (BET) and the size and volume of pores were also estimated.

Findings

Modification of the oxide composites with nonylphenylpolyoxyethyleneglycol ethers was found to improve the basic physico‐chemical parameters of the ZnO‐SiO2 hybrid systems and to change the character of its surface to become more hydrophobic. The conditions in which samples with the best properties were obtained were concluded to be optimum.

Research limitations/implications

Only the selected non‐ionic surfactants were applied as modifying agents of ZnO‐SiO2.

Practical implications

There is a possible application of ZnO‐SiO2 oxide composites as activators of rubber compounds and barrier materials in textiles.

Originality/value

The proposed method of ZnO‐SiO2 oxide composite synthesis in the process of precipitation with simultaneous modification with non‐ionic surfactants provides products with desirable dispersive‐morphological parameters and a hydrophobic surface character.

Article
Publication date: 12 January 2010

O.A. Hakeim, Qinguo Fan and Yong K. Kim

The purpose of this paper is to encapsulate aqueous dispersions of nano‐scale CI Pigment Red 122 prepared through ball milling into UV‐curable resins, 1,6 hexanediol…

1026

Abstract

Purpose

The purpose of this paper is to encapsulate aqueous dispersions of nano‐scale CI Pigment Red 122 prepared through ball milling into UV‐curable resins, 1,6 hexanediol diacrylate (HDDA, monomer), and polyester acrylate (oligomer) using the mini‐emulsion technique.

Design/methodology/approach

The encapsulation of pigment is achieved by mixing a surfactant‐stabilised pigment dispersions and a monomer/oligomer mini‐emulsions and subjecting both to mini‐emulsification conditions. A film of encapsulated pigment mini‐emulsion is finally UV cured using water‐soluble initiator. Efficient encapsulation is proven by ultra‐centrifugal sedimentation, scanning electron microscopy and thermogravimetric analysis (TGA). The stability of pigment dispersions and also the encapsulation process are investigated.

Findings

TGA and ultracentrifuge sedimentation results showed that CI Pigment Red 122 is successfully encapsulated into polyester acrylate/HDDA resins. The oligomer (polyester acrylate) in the presence of organic pigment could stabilise the mini‐emulsion droplets without introducing any other hydrophobes (co‐stabiliser) in the formulation. In addition, the encapsulation percentage and suspension stability of mini‐emulsion are best when the polyester acrylate/HDDA weight ratio is 3:2.

Research limitations/implications

The UV‐curable resins used in the present context are 1,6 HDDA and polyester acrylate. Besides, various oligomer/monomer composition types could be used and its impact on encapsulation efficiency could be also studied.

Practical implications

This method of encapsulation is practically effective for modification of organic pigments for use in UV‐curable ink‐jet printing inks.

Originality/value

The developed method is novel from a literature point of view and can be of a great benefit to achieve the required properties of pigmented UV‐curable system in inkjet printing of textiles. In addition, it could find numerous applications in surface coating.

Details

Pigment & Resin Technology, vol. 39 no. 1
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 27 May 2014

Mohsen Salehi Doolabi, Sayed Khatiboleslam Sadrnezhaad and Davood Salehi Doolabi

– The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath.

Abstract

Purpose

The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath.

Design/methodology/approach

Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated.

Findings

Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased the coating Al2O3 weight per cent significantly. Addition of Al3+ bath composition inhibited nanoparticle agglomeration, increasing film homogeneity. Cr–Al2O3 nanocomposites showed higher microhardness and better corrosion resistance than pure Cr layer.

Originality/value

Cr (III) is not as toxic and as carcinogenic as Cr (VI) which is widely used for Cr electroplating these days. Low current efficiency and poor product quality are, however, major drawbacks of the former. This paper describes significant improvements obtainable by addition of Al2O3 nanoparticles to the Cr (III) bath for increasing the microhardness, the corrosion resistance and the current efficiency of the deposition.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Content available
Article
Publication date: 1 August 2004

39

Abstract

Details

Pigment & Resin Technology, vol. 33 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 16 June 2010

Yulan Sun, Marc Thomas and Jacques Masounave

The purpose of this paper is to present experimental research on the behaviour of a new electrorheological fluid (ETSERF).

1974

Abstract

Purpose

The purpose of this paper is to present experimental research on the behaviour of a new electrorheological fluid (ETSERF).

Design/methodology/approach

The ETSERF is a suspension based on diatomite powders dispersed in silicon oil with a surfactant. A design of experiments is conducted to investigate the effects of electric field strength, particle concentration, surfactant percentage, particle size and shear rate on the efficiency of ETSERFs. The influence of the interactions on shear stresses is analyzed by varying all the combinations of the independent variables. The dielectric properties of the ETSERF are investigated in order to explain the interactions between these independent variables. Furthermore, a quantitative relationship between the dynamic shear stresses and the independent variables is developed.

Findings

The relationship provides a very useful explanation for the contributions of each independent variable to the viscosity and yield stress.

Originality/value

A new empirical model is proposed to explain the rheological behaviour of the ER fluids with a shear‐thinning behaviour.

Details

Multidiscipline Modeling in Materials and Structures, vol. 6 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 1 June 2001

Sven Berg

Aims to use some of the sampling techniques and sampling routines, mentioned in Part 1 of the article, to perform practical tests to determine their differences in…

1173

Abstract

Aims to use some of the sampling techniques and sampling routines, mentioned in Part 1 of the article, to perform practical tests to determine their differences in withdrawing samples. Uses two different types of systems, a hydraulic system and a gear system, together with some of the investigated sampling techniques. In order to find out the optimum sampling method for each of the two systems, uses a specification of requirements and a systematic approach, together with practical sample withdrawal from the two systems. For the hydraulic system, uses an on‐line particle counter and bottle samples from valves, and for the gear system, applies drain‐plug and vacuum pump sampling. It was found that for hydraulic systems on‐line sampling is the most appropriate, if information on the elements is not required. If information on the elements is required, bottle sampling from a valve together with flushing of the valve should be performed. For the gear system no difference was seen between the samples taken with a vacuum pump and those taken from the drain‐plug, and therefore an alternative method is suggested to improve the reliability of the sampling.

Details

Industrial Lubrication and Tribology, vol. 53 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

1 – 10 of 76