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Article
Publication date: 10 July 2017

Alaa Mohamed, Mohamed Hamdy, Mohamed Bayoumi and Tarek Osman

This work describes the fabrication of composite nanogrease based on carbon nanotubes (CNTs) as an additive at different volume concentrations 0, 0.5, 1, 2 and 3 Wt.% and…

Abstract

Purpose

This work describes the fabrication of composite nanogrease based on carbon nanotubes (CNTs) as an additive at different volume concentrations 0, 0.5, 1, 2 and 3 Wt.% and investigates the correlation between CNTs and grease rheological behaviour. In addition, study the influence of shear thinning rate at various temperatures and investigates the thermal conductivity of nanogrease. The results demonstrated that grease behaves like a Newtonian viscoelastic material with a narrow linear domain. The thermal conductivity of nanogrease was enhanced by about 31.58 per cent, and the thermal and mechanical stabilities improved. Moreover, the apparent viscosity and dropping point increased by about 93 and 27 per cent, respectively.

Design/methodology/approach

Grease was dissolved in chloroform (10 Wt.%), at 25°C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N,N-dimethylformamide; the dispersion was stirred for 15 min, and then sonicated (40 kHz, 150 W) for 30 min. Grease solution was then added to the CNTs. The nanofluid was magnetically stirred for 15 min and then sonicated for 2 h. This ensured uniform dispersion of nanoparticles in the base fluid.

Findings

Inexpensive and simple fabrication of nanogrease. Thermal conductivity of nanogrease was typically enhanced compared to other reported studies. Apparent viscosity and dropping point increases with the increase the volume concentration.

Originality/value

This work describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Details

Industrial Lubrication and Tribology, vol. 69 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 9 April 2018

Alaa Mohamed, Mohamed Hamdy, Mohamed Bayoumi and Tarek Osman

To enhance the tribological properties of nanogrease, one of the new technologies was used to synthesize a nanogrease having carbon nanotubes (CNTs) nanoparticles (NPs…

Abstract

Purpose

To enhance the tribological properties of nanogrease, one of the new technologies was used to synthesize a nanogrease having carbon nanotubes (CNTs) nanoparticles (NPs) with different concentrations. The microstructures of the synthesized NPs were characterized and evaluated by x-ray diffraction spectroscopy (XRD) and transmission electron microscopy (TEM). Tribological properties of the nanogrease were evaluated using a four-ball tester. The worn surface of four steel balls was investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX).

Design/methodology/approach

Grease was dissolved in chloroform (10 Wt.%), at 25 °C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N, N-dimethylformamide. The mixture was stirred for 15 min and then sonicated (40 kHz, 150 W) for 30 min. After that, the mixture was added to the grease solution and magnetically stirred for 15 min and then sonicated for 2 h.

Findings

The results suggested that CNTs can enhance the antiwear and friction properties of nanogrease at 0.5 Wt.% CNTs to about 57 and 48 per cent, respectively. In addition, the weld load of the base oil containing 0.5 Wt.% CNTs was improved by 17 per cent compared with base grease.

Originality/value

This work describes the inexpensive and simple fabrication of nanogrease for improving the properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Details

Industrial Lubrication and Tribology, vol. 70 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 12 March 2018

Mohamed Ashour, Alaa Mohamed, Abou Bakr Elshalakany, Tarek Osman and Aly Khatab

The purpose of this paper is to investigate the rheological characteristics of graphene nanoplatelets (GNPs) and hybridized nanocomposite consisting of multi-walled carbon…

Abstract

Purpose

The purpose of this paper is to investigate the rheological characteristics of graphene nanoplatelets (GNPs) and hybridized nanocomposite consisting of multi-walled carbon nanotubes (MWCNTs) and GNPs as an additive on lithium-based grease. The experiments of nanogrease are examined in different values of shear stress, apparent viscosity, temperature and shear rate using Brookfield Programmable Rheometer DV-III ULTRA and characterized by high-resolution transmission electron microscope (HRTEM) and X-ray diffraction (XRD).

Design/methodology/approach

First, GNPs was mixed well with lithium grease using mechanical stirring at 3,500 rpm for 15 min at room temperature to form a homogenous composite at different concentrations (0.5, 1, 1.5, 2 and 2.5 Wt.%). Afterwards, MWCNTs and GNPs are mixed and dispersed well in the lithium grease using a sonication path for 30 min and mechanical stirring at 3,500 rpm for 15 min at 28°C to form a homogenous nanocomposite.

Findings

The results indicated that 1 Wt.% of GNPs is the optimum concentration. Subsequently, the weight percentage of additives varying between MWCNTs and GNPs are tested, and the result indicate that the grease containing GNPs had a 75 per cent increase in shear stress and 93.7 per cent increase in apparent viscosity over ordinary grease.

Originality/value

This work describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Details

Industrial Lubrication and Tribology, vol. 70 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 16 August 2019

Ahmed Mobasher, Alaa Khalil, Medhat Khashaba and Tarek Osman

The purpose of this paper is to evaluate the influence of nanoparticles as an additive on the tribological properties of calcium grease.

Abstract

Purpose

The purpose of this paper is to evaluate the influence of nanoparticles as an additive on the tribological properties of calcium grease.

Design/methodology/approach

The nano additives in this research are with different concentration of multi carbon nanotubes (MWCNTs) and Talc powder (1, 2, 3, 3 and 5 per cent). The ratio of MWCNTs to Talc powder is 1:1. The tribological properties of hyper MWCNTs/Talc powder to calcium grease were evaluated using a pin-on-disk wear testing. The results show that the nano additives MWCNTs/Talc to calcium grease exhibit good performance in anti-wear and friction reduction. The action mechanism was estimated through analysis of the worm surface with x-ray diffraction and transmission electron microscope.

Findings

The result indicates that boundary film mainly composed of MWCNT and Talc powder, and other organic compound was formed on the worm surface during the friction test. In addition, the wear rate and coefficient of friction of nanogreases have shown excellent improvement about 80.62 and 63.44 per cent, respectively, at 4 Wt.% of MWCNTs/Talc powder. Moreover, the thermal conductivity of nanogrease increased about 51.72 per cent.

Originality/value

This study describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

Details

Industrial Lubrication and Tribology, vol. 72 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 9 April 2018

Shanhua Qian, Hongyue Wang, Chuanhui Huang and Yongwu Zhao

This paper aims to modify carbon nanotubes with oleic acid, and to study the tribological properties of castor oil with modified carbon nanotubes additives. The proper…

Abstract

Purpose

This paper aims to modify carbon nanotubes with oleic acid, and to study the tribological properties of castor oil with modified carbon nanotubes additives. The proper additives are sought for the future engineering application of castor oil.

Design/methodology/approach

Tribological properties of the castor oils mixed with the modified carbon nanotubes of four mass percentages were investigated using a four-ball testing rig. Coefficient of friction and wear scar diameter were obtained in each test, and the mechanism of modified carbon nanotubes and castor oil was discussed.

Findings

The results indicated that modified carbon nanotubes had better dispersion in castor oil. Coefficient of friction first increased, then decreased and finally grew stable with the time, and wear scar diameter of steel surface functioned as a first reduced then increased change with the additive mass percentage of modified carbon nanotubes. The minimum of average coefficient of friction and wear scar diameter occurred at 0.02 Wt.% modified carbon nanotubes.

Originality/value

A small amount of modified carbon nanotubes could improve properties of the castor oil, and the mixed castor oil with 0.02 Wt.% modified carbon nanotubes would be most possibly used in engineering applications.

Details

Industrial Lubrication and Tribology, vol. 70 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 December 2009

Mohammed Ibrahim Sultan Obeidat and Mohammed Abdullah Al Momani

This study investigates taxpayers’ perception to the Jordanian tax system efficiency according to the perspective of Keynes. Its main purpose is to determine whether…

Abstract

This study investigates taxpayers’ perception to the Jordanian tax system efficiency according to the perspective of Keynes. Its main purpose is to determine whether taxpayers perceive the Jordanian tax system as efficient, enough to influence taxpayers’ patterns of behavior, or inefficient and just used to collect revenue by the government. A self‐administered questionnaire is used to collect the primary data of the study, in order to measure the economical and socio‐cultural efficiency of the system. A convenience sample consisting of 175 respondents was selected to survey how taxpayers perceive the Jordanian tax system efficiency. The t‐test is used as a decision criterion for the acceptance or rejection of the hypotheses. Correlation analysis is also used to support the findings of the study. The study finds that taxpayers perceive the Jordanian tax system as efficient, and they perceive that the tax system is intentionally used to influence their behavior.

Details

Journal of Economic and Administrative Sciences, vol. 25 no. 2
Type: Research Article
ISSN: 1026-4116

Keywords

Content available
Article
Publication date: 11 June 2019

Mohamed Othman Elkhosht

The purpose of this paper is to draw a map of the general features of epistemological and critical concerns in contemporary Islamic philosophy. This study will not be…

Abstract

Purpose

The purpose of this paper is to draw a map of the general features of epistemological and critical concerns in contemporary Islamic philosophy. This study will not be confined to the domain of academic philosophy or to those who are professionals in the field of philosophy.

Design/methodology/approach

The paper adopted the critical rational approach in dealing with contemporary Islamic philosophy in the Arab world. The scope will include scholars from different fields of epistemology who tried to present a “vision” of the attitude that should be adopted in facing the challenges of the age and the problems of the nation on the epistemological level or the political, economic and social levels.

Findings

There is a need for a philosophy of action and progress rather than a philosophy that is based on abstract ideas and theories and of words/rhetoric. The ethics required to accomplish this ought to identify the attributes of the citizen who can reach self-actualization through legitimate means based on a progress agenda with theoretical and philosophical foundations.

Research limitations/implications

Because a critical rational approach can be dealt with from different perspectives, this paper will adopt the classification of the principal intellectual trends: the reformist, secular and liberal.

Practical implications

This paper covers a long time span to determine whether the philosophical projects have been effective.

Originality/value

This paper, which criticizes the philosophic projects that are theoretically unsound and that do not address real social problems (like poverty), argues the need for a philosophy of progress and action. This will lead to devising an agenda that addresses the challenges the society is facing and to finding alternative and creative solutions resulting in development.

Details

Journal of Humanities and Applied Social Sciences, vol. 1 no. 1
Type: Research Article
ISSN: 2632-279X

Keywords

Content available
Article
Publication date: 6 September 2018

Doaa Salman Abdou and Zeinab Zaazou

This paper aims to shed light on the Egyptian socio-economic and political conditions seven years post the 2011 revolution.

Abstract

Purpose

This paper aims to shed light on the Egyptian socio-economic and political conditions seven years post the 2011 revolution.

Design/methodology/approach

The authors depended on secondary data and information gathered from scholars and from domestic and international institutions as well. Additionally, the authors distributed 390 Likert-scale questionnaires among respondents to test their perceptions regarding the safety, social, political and economic conditions in Egypt seven years post the 2011 revolution.

Findings

The research findings confirmed that there was an agreement among participants that the safety conditions in Egypt improved during the past seven years post the 2011 revolution, and there was a general agreement among participants that the political conditions in Egypt became more stable lately. The economic and social cost presents a challenging status to the current decision maker.

Practical implications

Finally, authors came up with recommendations aiming to find solutions for certain economic and political problematic issues. The main research limitation is that the representative sample was confined only to the two main governorates in Egypt: Cairo and Giza.

Originality/value

Finally, the study is of a value, as it could be considered a road map to policy makers. Moreover, the findings provide a set of policies for governments to undertake tenable actions to accelerate development and economic growth.

Details

Review of Economics and Political Science, vol. 3 no. 2
Type: Research Article
ISSN: 2631-3561

Keywords

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Article
Publication date: 6 September 2013

Zuhair Malaibari, Ramazan Kahraman and Abdur Rauf

The purpose of this study was to investigate the performances of three inhibitors in controlling corrosion of local mild steel products in distilled water and a simulated…

Abstract

Purpose

The purpose of this study was to investigate the performances of three inhibitors in controlling corrosion of local mild steel products in distilled water and a simulated salt solution.

Design/methodology/approach

Corrosion inhibition of mild steel was investigated using electrochemical techniques. Untreated and inhibitor treated specimens were fully immersed in two test solutions, distilled water and the simulated solution of 2.0 wt.% NaCl and 1.0 wt.% Na2SO4.

Findings

During full immersion in the simulated salt solution, sodium dihydrogen orthophosphate was not effective at all, resulting in even higher corrosion rates than that of the untreated specimens. Sodium benzoate was effective for three days only. Dicyclohexylamine nitrite was the most effective of them all, keeping its effectiveness for as much as 20 days. When the specimens were immersed in distilled water, all three inhibitors were effective during the 60 days of immersion while dicyclohexylamine nitrite and sodium benzoate treated specimens performed better than those treated with sodium dihydrogen orthophosphate.

Originality/value

The objective of this research was to investigate the performances of three inhibitors – sodium dihydrogen orthophosphate (inorganic) at 10 mM concentration, dicyclohexylamine nitrite (organic) and sodium benzoate (organic) at 100 mM concentration – in controlling the corrosion of local mild steel products fully immersed in two test solutions, distilled water and the simulated salt solution. All three inhibitors are film forming and anodic type inhibitors. According to the authors' literature review, this study is original and will add value to the studies of inhibition of steel corrosion under similar environments.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 7 November 2016

Alvaro A. Rodriguez, Chelsea N. Monty, Christopher M. Miller, Hongbo Cong and Evan K. Wujcik

The purpose of this study is to develop laboratory techniques to evaluate the inhibition efficiency of salt neutralizer (SN) solutions in the corrosion protection of metal…

Abstract

Purpose

The purpose of this study is to develop laboratory techniques to evaluate the inhibition efficiency of salt neutralizer (SN) solutions in the corrosion protection of metal alloys associated with winter maintenance equipment.

Design/methodology/approach

The corrosion resistance of alloys A36, B36 and B152 treated with SNs was evaluated by accelerated corrosion testing (ASTM B117) and electrochemical polarization curves. Characterization of inhibition solutions was performed by contact angle measurements, scanning electron microscopy, ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy.

Findings

Salt neutralizer systems act as mixed inhibitors in acidic media by changing the corrosion resistance ability of metal alloys because of the adsorption of surfactant molecules through their hydrophilic heads. The correlation of the corrosion rate of metal alloys and the inhibitor efficiency showed the influence of the SN type, its concentration, its effective adsorption constant and its contact angle on the alloy surface. Salt neutralizers with higher manufacturer’s recommended wash concentrations (MRWC) to critical wash concentration ratio, lower contact angle on the alloy surface and higher Keff were more successful at preventing corrosion on the alloys tested.

Originality/value

The results of this work provide, for the first time, both quantitative and qualitative information of the properties of washing techniques in the use of effective cleaning strategies for protecting winter maintenance equipment from corrosion. Other state departments of transportation facing similar weather conditions will be benefited by identifying measures and techniques to increase the corrosion resistance of their equipment assets.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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