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Article
Publication date: 8 May 2018

M.M. Shahin, Mohammad Asaduzzaman Chowdhury, Md. Arefin Kowser, Uttam Kumar Debnath and M.H. Monir

The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain…

232

Abstract

Purpose

The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain, total deformation and stress formation.

Design/methodology/approach

A journal bearing test rig was used to determine the effect of the applied load on the bearing friction, film thickness, lubricant film pressure, etc. A steady-state analysis was performed to obtain the bearing performance.

Findings

An efficient aspect ratio (L/D) range was obtained to increase the durability or the stability of the bearing while the bearing is in the working condition by using SAE 5W-30 oil. The results from the study were compared with previous studies in which different types of oil and water, such as Newtonian fluid (NF), magnetorheological fluid (MRF) and nonmagnetorheological fluid (NMRF), were used as the lubricant. To ensure a preferable aspect ratio range (0.25-0.50), a computational fluid dynamics (CFD) analysis was conducted by ANSYS; the results show a lower elastic strain and deformation within the preferable aspect ratio (0.25-0.50) rather than a higher aspect ratio using the SAE 5W-30 oil.

Originality/value

It is expected that the findings of this study will contribute to the improvement of the bearing design and the bearing lubricating system.

Details

Industrial Lubrication and Tribology, vol. 70 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 19 September 2019

Qiang Li, Shuo Zhang, Yujun Wang, Wei-Wei Xu, Zengli Wang and Zhenbo Wang

Shear stresses have a considerable influence on the characteristics of lubricants and become significant at high rotating speeds. This study aims to investigate the influences of…

166

Abstract

Purpose

Shear stresses have a considerable influence on the characteristics of lubricants and become significant at high rotating speeds. This study aims to investigate the influences of shear cavitation (SC) on loading capacity of journal bearings.

Design/methodology/approach

A principal normal stress cavitation criterion based on the stress applied to flowing lubricant in journal bearings is developed and used to investigate SC in journal bearings. A computational fluid dynamic (CFD) model for calculating the loading capacity is established using this criterion. After validation with experimental results, the loading capacity is calculated under different conditions.

Findings

The calculation results indicate that SC intensifies when viscosity, speed and eccentricity increase. Angle of loading capacity with SC is larger than that without SC. The magnitude of loading capacity with SC is smaller than that without SC due to the decrease in the ultimate pressure. In addition, the magnitude difference between the loading capacity with and without SC increases when viscosity, speed and eccentricity increases.

Originality/value

Present research can provide some guidance for calculating the loading capacity when a journal bearing is operating at high speed or with a high viscosity lubricant.

Details

Industrial Lubrication and Tribology, vol. 71 no. 9
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 10 October 2018

Monir Sadat Hosseini, Hamid Javadi and Sadegh Vaez-Zadeh

This paper aims to investigate analytical electromagnetic fields and thrust ripples representation of linear flux-switching motors with simple modulated secondary referred as…

101

Abstract

Purpose

This paper aims to investigate analytical electromagnetic fields and thrust ripples representation of linear flux-switching motors with simple modulated secondary referred as segmented secondary linear flux-switching motor (SSLFSM).

Design/methodology/approach

SSLFSMs are applicable to transportation systems like Maglev due to their simple and consequently low-cost secondary structures and high force density. However, they have high thrust ripples that deteriorate a smooth motion in rail transportation systems. Therefore, derivation of accurate analytical models for thrust ripples minimization of the motor is essential, which is absent in the literature. In this paper, a two-dimensional analytical model is developed for this motor. The model is based on transfer relations and Fourier theory used for solving a two-dimensional boundary value problem. Certain model regions are determined by considering actual machine structure and observing specific rules. Analytical solution of Maxwell and Poison equations are then obtained in the regions.

Finding

Using the presented modeling method, the airgap electromagnetic field distribution and developed thrust of the motor are calculated for different positions of the motor as well as its thrust ripples. They are verified by the results obtained from finite element method. Also, the analytical results are compared with the presented experimental results.

Originality/value

This paper has analytically presented the airgap electromagnetic field distribution, thrust and thrust ripples of the SSLFSMs. This modeling is essential in thrust ripples minimization of the motor.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 3 April 2017

Sameh Monir El-Sayegh and Rana Al-Haj

The purpose of this paper is to propose a new framework for time–cost trade-off. The new framework provides the optimum time–cost value taking into account the float loss impact.

355

Abstract

Purpose

The purpose of this paper is to propose a new framework for time–cost trade-off. The new framework provides the optimum time–cost value taking into account the float loss impact.

Design/methodology/approach

The stochastic framework uses Monte Carlo Simulation to calculate the effect of float loss on risk. This is later translated into an added cost to the trade-off problem. Five examples, from literature, are solved using the proposed framework to test the applicability of the developed framework.

Findings

The results confirmed the research hypothesis that the new optimum solution will be at a higher duration and cost but at a lower risk compared to traditional methods. The probabilities of finishing the project on time using the developed framework in all five cases were better than those using the classical deterministic optimization technique.

Originality/value

The objective of time–cost trade-off is to determine the optimum project duration corresponding to the minimum total cost. Time–cost trade-off techniques result in reducing the available float for noncritical activities and thus increasing the schedule risks. Existing deterministic optimization technique does not consider the impact of the float loss within the noncritical activities when the project duration is being crashed. The new framework allows project managers to exercise new trade-offs between time, cost and risk which will ultimately improve the chances of achieving project objectives.

Details

Journal of Financial Management of Property and Construction, vol. 22 no. 1
Type: Research Article
ISSN: 1366-4387

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Article
Publication date: 16 July 2021

Dure Jabeen, S.M. Ghazanfar Monir, Shaheena Noor, Muhammad Rafiullah and Munsif Ali Jatoi

Watermarking technique is one of the significant methods in which carrier signal hides digital information in the form of watermark to prevent the authenticity of the stakeholders…

71

Abstract

Purpose

Watermarking technique is one of the significant methods in which carrier signal hides digital information in the form of watermark to prevent the authenticity of the stakeholders by manipulating different coefficients as watermark in time and frequency domain to sustain trade-off in performance parameters. One challenging component among others is to maintain the robustness, to limit perceptibility with embedding information. Transform domain is more popular to achieve the required results in color image watermarking. Variants of complex Hadamard transform (CHT) have been applied for gray image watermarking, and it has been proved that it has better performance than other orthogonal transforms. This paper is aimed at analyzing the performance of spatio-chromatic complex Hadamard transform (Sp-CHT) that is proposed as an application of color image watermarking in sequency domain (SD).

Design/methodology/approach

In this paper, color image watermarking technique is designed and implemented in SD using spatio-chromatic – conjugate symmetric sequency – ordered CHT. The color of a pixel is represented as complex number a*+jb*, where a* and b* are chromatic components of International Commission on Illumination (CIE) La*b* color space. The embedded watermark is almost transparent to human eye although robust against common signal processing attacks.

Findings

Based on the results, bit error rate (BER) and peak signal to noise ratio are measured and discussed in comparison of CIE La*b* and hue, saturation and value color model with spatio-chromatic discrete Fourier transform (Sp-DFT), and results are also analyzed with other discrete orthogonal transforms. It is observed from BER that Sp-CHT has 8%–12% better performance than Sp-DFT. Structural similarity index has been measured at different watermark strength and it is observed that presented transform performs better than other transforms.

Originality/value

This work presents the details and comparative analysis of two orthogonal transforms as color image watermarking application using MATLAB software. A finding from this study demonstrates that the Complex Hadamard transform is the competent candidate that can be replaced with DFT in many signal processing applications.

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Article
Publication date: 13 July 2023

Haitham Alajmani, Salma Ahmed and Sameh Monir El-Sayegh

This paper aims to measure the severity, frequency and importance of the factors causing delays in the United Arab Emirates (UAE) construction industry following the Covid-19…

225

Abstract

Purpose

This paper aims to measure the severity, frequency and importance of the factors causing delays in the United Arab Emirates (UAE) construction industry following the Covid-19 pandemic onset. The study also measures the likelihood of the effects caused by these delays.

Design/methodology/approach

A mixed approach of both qualitative and quantitative. Literature review was conducted to extract 40 factors of delays and 10 effects of delays. A survey was then administered to construction professionals in the UAE to collect the perceptions on the severity and frequency of factors of the causes of delays using a Likert Scale of 1–5 where 1 represented very low and 5 represented very high. Similarly, the respondents were also asked to rate the likelihood of the occurrence of the effects of the delays based on a Likert scale of 1–5 as well. Furthermore, Spearman’s rank correlation was also conducted to compute the level of agreement between the different parties; owner, consultants and contractors.

Findings

The results revealed that the top five factors of delays include: award the project for the lowest bidder, delay in progress payment, change orders by the owner, poor subcontractor performance and inadequate planning and scheduling by the contractor. The findings of this study emphasize the financial challenges and economic crisis brought upon the construction industry due to the pandemic. Furthermore, the pandemic also shifted the perceptions of construction professionals, who are now more aware of the delays caused by awarding the project to the lowest bidder who would not have the required qualifications to conduct efficient planning and scheduling that are relevant in the case of extraordinary events such as Covid-19. Moreover, a high level of agreement between the consultants and contractors was observed, with a Spearman’s rank correlation of 0.804. Additionally, the most likely effects of delays concluded from this study were time overrun/extension and poor quality of work.

Originality/value

Literature review is very rich in the field of construction projects delays. However, there is very limited research on the impact of Covid-19 in the context of construction projects delays, and insights from construction professionals regarding this matter are particularly lacking in literature. Therefore, this paper bridges the gap in literature by providing perceptions of construction professionals on the impact of Covid-19 on the factors causing delays in the UAE construction industry. The findings of this research are expected to be an invaluable resource for future to help the construction industry heal faster when encountering similar epidemics or extraordinary events.

Details

Journal of Financial Management of Property and Construction , vol. 29 no. 1
Type: Research Article
ISSN: 1366-4387

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Book part
Publication date: 7 December 2023

Simona-Andreea Apostu and Iza Gigauri

This chapter is devoted to sustainable human resource management that leads to sustainable competitiveness. It features the ways human resources can be managed to carry out…

Abstract

This chapter is devoted to sustainable human resource management that leads to sustainable competitiveness. It features the ways human resources can be managed to carry out sustainable goals and the impact of sustainability on employees' attitudes and behaviours. The aim of this study is to explore the complex objectives of sustainability and human resource management and empirically investigate the dynamic relationship between human resources in science and technology and sustainable competitiveness in the case of 35 European countries. Our contribution emphasizes this interrelationship and its causality. For this research, we applied a vector auto-regression (VAR) model, and the Granger causality method to examine the relationship between human resources in science and technology and sustainable competitiveness. A panel data included 314 observations between 2012 and 2021. The panel VAR for analysing the impulse response function was enriched with the 5% and 95%, using Monte Carlo simulations. The research results revealed bidirectional causality in the European countries between human resources in science and technology and sustainable competitiveness. Human resources in science and technology trigger sustainable competitiveness and vice versa. As an element of originality, our study demonstrates that human resources in science and technology contribute to sustainable performance, and, on the other hand, a more competitive and sustainable environment contributes to the development of human resources in science and technology. Thus, the chapter outlines the role of human resources in science and technology with regard to sustainable human resource management (HRM), and how to navigate these objectives so that they can positively influence sustainable competitiveness.

Details

Reshaping Performance Management for Sustainable Development
Type: Book
ISBN: 978-1-83797-305-7

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Article
Publication date: 2 August 2024

Salma Ahmed, Lotfi Romdhane, Sameh Monir El-Sayegh and Solair Manjikian

The purpose of this study is to identify and assess new risks in construction projects that use 3D printing.

123

Abstract

Purpose

The purpose of this study is to identify and assess new risks in construction projects that use 3D printing.

Design/methodology/approach

A mixed approach of both qualitative and quantitative methods was used. Literature review was conducted to extract 30 risks of 3D printing in construction. A survey was then developed to assess the probability and impact of these risks. In total, 37 respondents, who have experience and/or knowledge of 3D printing, completed the survey. The risk priority was calculated using a fuzzy logic approach. The main benefit of the proposed model is being able to use numerical and linguistic data in the risk assessment model.

Findings

The results show that the main risks, in terms of priority, are lack of codes and regulations for 3D printing in construction, delay in government approvals, shortage in labour skilled in 3D printed construction, lack of knowledge and information of 3D printed design concepts and changes in 3D construction codes and regulations.

Originality/value

This paper fills an identified gap in the literature related to 3D printing in construction and provides insights into the key risks affecting this disruptive technology.

Details

Journal of Financial Management of Property and Construction , vol. 30 no. 1
Type: Research Article
ISSN: 1366-4387

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Article
Publication date: 2 May 2017

Bikram Chatterjee, Monir Zaman Mir, Ian A. Eddie and Victoria Wise

The purpose of this paper is to identify the contextual factors affecting infrastructure reporting by New Zealand local authorities.

653

Abstract

Purpose

The purpose of this paper is to identify the contextual factors affecting infrastructure reporting by New Zealand local authorities.

Design/methodology/approach

The paper includes a survey and interview of Annual Report Recipients (ARRs) and Infrastructure Information Preparers (IIPs), together with an assessment of the extent of infrastructure information disclosure in the annual reports of New Zealand local authorities.

Findings

This study finds that contrary to the expectations of Lüder’s contingency model (1992), there is an information dissemination gap between the perceptions of ARRs and IIPs regarding infrastructure information reporting in the annual reports of New Zealand local authorities. This finding is consistent with decades of concern about the application of private sector Generally Accepted Accounting Principles to the public sector and the Controller and Auditor General’s (CAG, 2009) concern about the inadequacy of private sector General Purpose Financial Reports in meeting public sector accountability. On the other hand, the study reports that the perceptions of the two groups, ARRs and IIPs, are similar with regard to the importance of infrastructure information items, which is consistent with the expectations of Lüder’s model.

Originality/value

The paper contributes towards theoretical development by adopting Lüder’s (1992) contingency model in the context of infrastructure reporting by New Zealand local authorities and proposing a model of contextual factors by extending Lüder’s model. The practical contribution of the study is in the area of accounting practice and public policy.

Details

Accounting Research Journal, vol. 30 no. 01
Type: Research Article
ISSN: 1030-9616

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Article
Publication date: 25 October 2017

Monir Mir, Haiwei Fan and Ian Maclean

The paper aims to explore whether different models of public sector audit exist in China without adhering to the goals and objectives of public sector audit systems in democratic…

1484

Abstract

Purpose

The paper aims to explore whether different models of public sector audit exist in China without adhering to the goals and objectives of public sector audit systems in democratic jurisdictions.

Design/methodology/approach

The study is based on a single embedded case study involving multiple methods of data collection including public documents, semi-structured interviews and site visits. The research methods and the analytical framework of the study draw on the concepts of political competition, public sector accountability and audit independence.

Findings

The study finds that the Chinese National Audit Office’s (CNAO) objectives derive from the neo-classical economic discourse and not from ideas of public accountability, as is the case in democratic parliamentary jurisdictions. The study finds that public sector audit in China functions in ways which are similar to that of internal audit. The CNAO may provide limited political and public accountability for Chinese public officials indirectly by enhancing their managerial accountabilities.

Research limitations/implications

The study goes against the prevailing view that supreme audit institutions which are part of the executive will lead to poor accountability of the public sector and increased public sector corruption.

Practical implications

The study suggests that enhancing managerial accountability in non-democratic (and pseudo-democratic) jurisdictions through public sector audit can by itself be of significant benefit. Further, such enhancements may also strengthen public sector accountability.

Originality/value

This paper fills a research gap by exploring public sector audit independence in a developing country with a unitary system of government.

Details

Managerial Auditing Journal, vol. 32 no. 9
Type: Research Article
ISSN: 0268-6902

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