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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

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: 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: 20 July 2020

Tarek Ben Hassen

The purpose of this paper is to examine the current state of the knowledge-based economy in two distinctive case studies in the Arab World: Qatar and Lebanon. Based on…

Abstract

Purpose

The purpose of this paper is to examine the current state of the knowledge-based economy in two distinctive case studies in the Arab World: Qatar and Lebanon. Based on five aspects of the knowledge-based economy namely: ICT, human capital and education; innovation, entrepreneurship, and economic and institutional regime, we provide a careful view of the obstacles and challenges that Qatar and Lebanon are facing and how this is hindering their transformation to a knowledge-based economy.

Design/methodology/approach

The methodology of this research is based on a literature review and information collected through semi-structured interviews with the different stakeholders of the knowledge-based economy in Qatar and Lebanon.

Findings

The research reveals that numerous factors shape the knowledge-based economy in Qatar and Lebanon. In Qatar, the main strength of the knowledge-based economy is the determination of the Qatari government to diversify the economy and the main weaknesses are the shortage of qualified human resources, the fear of failure and the low performance of the innovation system. In Lebanon, the knowledge-based economy is driven by the education system and the entrepreneurship culture, nevertheless the political instability of the country and the weak ICT infrastructure impede its development.

Originality/value

These findings contribute to the clarification and critical analysis of the current state of the knowledge-based economy in Qatar and Lebanon, which would have several policy implications.

Details

EuroMed Journal of Business, vol. 16 no. 2
Type: Research Article
ISSN: 1450-2194

Keywords

Content available
Article
Publication date: 9 March 2020

Tarek Ben Hassen

The purpose of this paper is to analyze the characteristics and dynamics of the entrepreneurship ecosystem in the ICT sector in Qatar.

Abstract

Purpose

The purpose of this paper is to analyze the characteristics and dynamics of the entrepreneurship ecosystem in the ICT sector in Qatar.

Design/methodology/approach

The methodology of this research is based on a literature review and information collected through semistructured interviews with the different stakeholders involved in the entrepreneurship ecosystem in the ICT sector in Qatar.

Findings

The results show that two opposite forces shape the entrepreneurship ecosystem in the ICT sector in Qatar. On one hand, the strong determination and intervention of the Qatari government to diversify the economy by creating a vibrant ecosystem in the ICT sector. On the other hand, entrepreneurs in this sector are still facing some barriers and difficulties, and those issues are tightly related to Qatar's economic characteristics as a rentier state whose economy is driven by hydrocarbon resources.

Originality/value

These findings contribute to the clarification and critical analysis of the current dynamics of the entrepreneurship ecosystem in the ICT sector in Qatar, which would have several policy implications.

Details

Journal of Small Business and Enterprise Development, vol. 27 no. 2
Type: Research Article
ISSN: 1462-6004

Keywords

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Article
Publication date: 12 March 2018

Samy Shaban, Abd Elaziz Fouda, Mohamed Elmorsi, Tarek Fayed and Omar Azazy

The purpose of this study is to inspect the corrosion inhibition of API N80 steel pipelines in uninhibited solution and inhibited with a synthesized surfactant compound…

Abstract

Purpose

The purpose of this study is to inspect the corrosion inhibition of API N80 steel pipelines in uninhibited solution and inhibited with a synthesized surfactant compound [N-(3-(dimethyl octyl ammonio) propyl) palmitamide bromide] (DMDPP), which is prepared through a simple and applicable method.

Design/methodology/approach

Weight loss was inspected at five different temperatures of 25°C, 30°C, 40°C, 50°C and 60°C Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation were used at room temperature. Density functional theory was used to study the relation between the molecular structure and inhibition theoretically.

Findings

Adsorption of the prepared DMDPP fits the Langmuir isotherm model. The inhibition efficiency of the prepared DMDPP amphipathic inhibitor is directly proportional to temperature increase. Polarization results reveal that the investigated DMDPP amphipathic compound behaves as a mixed-type inhibitor. EIS spectra produced one individual capacitive loop.

Originality/value

The originality is the preparation of cationic surfactants through a simple method, which can be used as corrosion inhibitors in oil production. The synthesized inhibitors were prepared from low-price materials. The work studied the behavior of the synthesized surfactants in inhibiting the corrosion of the steel in an acidic medium. Electrochemical and theoretical studies were presented, besides gravimetric and surface examination.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 4 January 2021

Faisal Faqih, Tarek Zayed and Ghasan Alfalah

A building deteriorates over time due to aging, wear and tear, and inadequate maintenance. Building diagnosis requires a sound knowledge of engineering, building defects…

Abstract

Purpose

A building deteriorates over time due to aging, wear and tear, and inadequate maintenance. Building diagnosis requires a sound knowledge of engineering, building defects, and detection tools to assess the condition of a building. The physical deterioration of a building reduces its ability to perform its intended function, while environmental deterioration influences the comfort and health of building occupants. This study presents a multi-tiered framework for the inspection of building elements and the environmental conditions of a building.

Design/methodology/approach

A three-tiered building inspection framework is proposed in this study, which consists of the following: Tier-I—a preliminary inspection, Tier-II—a detailed inspection, and Tier-III—an expert investigation. Each tier of inspection assesses the severity of building defects using different technologies for different levels of inspection.

Findings

Proposed multi-tier inspection framework is tested and implemented on a case study. Results were promising, with organized data management on a common platform for both physical and environmental condition inspection having the potential to save time.

Originality/value

The application program developed for the implementation of structured multi-tiered building inspection provides better documentation and data management for building inspection data that can save time involved in manual data operations in traditional paper-based processes.

Details

International Journal of Building Pathology and Adaptation, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2398-4708

Keywords

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Article
Publication date: 14 June 2019

Zul-Atfi Ismail

The improper management of conventional systems for recording, diagnosing and analysing information appears to be a major problem in the maintenance of heritage buildings…

Abstract

Purpose

The improper management of conventional systems for recording, diagnosing and analysing information appears to be a major problem in the maintenance of heritage buildings. This is because of a lack of detection of patent or latent defects, ineffective repair methods and inappropriate planning decisions, which increase the risks of failure throughout the lifetime of heritage buildings. The paper aims to discuss this issue.

Design/methodology/approach

The concept of maintenance management practices, as well as techniques and tools from information and communication technology, was reviewed to identify suitable processes and construct an information database of maintenance and management techniques. A maintenance index framework was then formulated by analysing these concepts.

Findings

The initial findings identify the need for decision-making support in the diagnosis of heritage building maintenance based on robust data collection. This should include the selection of a durable replacement design and material or an appropriate rehabilitation method for managing quality and reducing associated defects.

Originality/value

Further research into the maintenance of heritage buildings should consider various aspects in terms of sustainability. The paper concludes that implementing a maintenance index framework can help improve the decision-making performance with regard to the design, construction and maintenance operations of heritage concrete buildings.

Details

International Journal of Building Pathology and Adaptation, vol. 37 no. 5
Type: Research Article
ISSN: 2398-4708

Keywords

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Article
Publication date: 27 May 2020

Marwa M. El-Ashmouni and Ashraf M. Salama

The purpose of this paper is to develop an analytical account on the contemporary architecture of Cairo with emphasis on the past three decades, from the early 1990s to…

Abstract

Purpose

The purpose of this paper is to develop an analytical account on the contemporary architecture of Cairo with emphasis on the past three decades, from the early 1990s to the present. The paper critically analyses narratives of the plurality of “isms”, within architectural vocabulary and discourse, that resulted from the contextual particularities that shaped it.

Design/methodology/approach

Three lines of inquiry are envisioned as overarching aspects of architecture: the chronological, the interventional and the representational. These discussions are underpinned by the discourse of decolonialisation and cosmopolitanism, posited sequentially by Frantz Fanon in The Wretched of the Earth (1961), and Ulrich Beck in The Cosmopolitan Vision (2004). The analysis expands to interrogate these two notions as prelude for reflecting on representations of selected projects: The Smart Village (2001); the Great Egyptian Museum (2002), Al-Azhar Park (2005), American University in Cairo New Campus (2008/2009), and the New Administrative Capital (2018).

Findings

The investigation on the interventional and the representational levels via aspects of discursivity and contradictions highlights that decolonisation and cosmopolitanism are two inseparable facets in the architectural practice in Egypt’s 21st century. These indivisible notions are based on idiosyncratic core to human experience, which emerged from concurrent overturning historical and secular everyday life striving to suppress ideological supremacy.

Research limitations/implications

Further detailed examples can be developed to offer discerning elucidations relevant to both notions of cosmopolitanism and decolonialisation.

Originality/value

The paper offers novel theoretical analysis of Cairo’s most recent architecture. The reflection on the notions of decolonialisation and cosmopolitanism is a timely example of the complex cultural encounters that have shaped the Egyptian architecture, given the recent interventions by the “Modern State” that legitimised such notions.

Details

Open House International, vol. 45 no. 1/2
Type: Research Article
ISSN: 0168-2601

Keywords

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