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1 – 10 of over 6000M.S. Ibrahim, R.M. Mohsen and S.M. El‐Sawy
Reports on the preparation of some organic corrosion inhibitors, carried out by the reaction of epoxidized linseed oil free fatty acids with different aliphatic amines under the…
Abstract
Reports on the preparation of some organic corrosion inhibitors, carried out by the reaction of epoxidized linseed oil free fatty acids with different aliphatic amines under the effect of γ‐ray irradiation. Notes that chemical and instrumental methods were used for identification of the reaction products and that the prepared inhibitors were tested for corrosion protection of steel surfaces by incorporating them in some chlorinated rubber varnishes. Reports that the physical, chemical and corrosion protective properties of the varnish films were studied. Concludes that the prepared inhibitors can be used in small quantities to provide varnishes of excellent adhesion and superior protective properties. Contends, also, that increase of the radiation dose during preparation of the inhibitors and/or during the drying process of the varnish films increases the protective properties of the formed films.
K. Suneetha, S.M. Ibrahim and G.V. Ramana Reddy
The purpose of this paper is to address the combined effects of thermal radiation and chemical reaction on steady MHD mixed convective heat and mass transfer flow past a vertical…
Abstract
Purpose
The purpose of this paper is to address the combined effects of thermal radiation and chemical reaction on steady MHD mixed convective heat and mass transfer flow past a vertical surface under the influence of Joule and viscous dissipation.
Design/methodology/approach
The governing system of partial differential equations is transformed to dimensionless equations using dimensionless variables. The dimensionless equations are then solved analytically using perturbation technique.
Findings
With the help of graphs, the effects of the various important parameters entering into the problem on the dimensionless velocity, dimensionless temperature and dimensionless concentration fields within the boundary layer are discussed. The authors noticed that the velocity increases with an increase in the porosity parameter. An increase in the Prandtl number Pr, decreases the velocity and the temperature field. An increase in the radiation parameter, decreases the velocity and the temperature field. Also the effects of the pertinent parameters on the skin-friction coefficient and rates of heat and mass transfer in terms of the Nusselt and Sherwood numbers are presented numerically in tabular form.
Originality/value
To the best of the authors’ knowledge, recent this work has not been finished by any other researchers.
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V. V. Singh, Abubakkar Idris Mohhammad, Kabiru Hamisu Ibrahim and Ibrahim Yusuf
This paper analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The…
Abstract
Purpose
This paper analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The computed results are more supportable for repairable system performability analysis.
Design/methodology/approach
In this paper, the authors have analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The supplementary variable technique has employed for analyzing the performance of the system.
Findings
Reliability measures have been computed for different types of configuration. It generalized the results for purely series and purely parallel configurations.
Research limitations/implications
This research may be beneficial for industrial system performances whereas a k-out-of-n-type configuration exists.
Practical implications
Not sure as it is a theoretical assessment.
Social implications
This research may not have social implications.
Originality/value
This work is the sole work of authors that have not been communicated to any other journal before.
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K. Suneetha, S.M. Ibrahim and G.V. Ramana Reddy
The purpose of this paper is to investigate the steady 2D buoyancy effects on MHD flow over a permeable stretching sheet through porous medium in the presence of suction/injection.
Abstract
Purpose
The purpose of this paper is to investigate the steady 2D buoyancy effects on MHD flow over a permeable stretching sheet through porous medium in the presence of suction/injection.
Design/methodology/approach
Similarity transformations are employed to transform the governing partial differential equations into ordinary differential equations. The transformed equations are then solved numerically by a shooting technique.
Findings
The working fluid is examined for several sundry parameters graphically and in tabular form. It is observed that with an increase in magnetic field and permeability of porous parameter, velocity profile decreases while temperature and concentration enhances. Stretching sheet parameter reduces velocity, temperature and concentration, whereas it increases skin friction factor, Nusselt number and Sherwood number.
Originality/value
Till now no numerical studies are reported on the effects of heat source and thermal radiation on MHD flow over a permeable stretching sheet embedded in porous medium in the presence of chemical reaction.
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Mohamed Ibrahim A. Othman and Mohamed Ibrahim M. Hilal
The purpose of this paper is to study the effect of rotation and initial stress on magneto-thermoelastic material with voids heated by a laser pulse heating.
Abstract
Purpose
The purpose of this paper is to study the effect of rotation and initial stress on magneto-thermoelastic material with voids heated by a laser pulse heating.
Design/methodology/approach
The analytical method used was the normal mode analysis technique.
Findings
Numerical results for the physical quantities were presented graphically and analyzed. The graphical results indicate that the effect of rotation, initial stress and magnetic fields are observable physical effects on the thermoelastic material with voids heated by a laser pulse. Comparisons are made with the results in the absence and the presence of the physical operators, also at various times.
Originality/value
In the present work, the authors shall investigate the effect of the rotation, initial stress, magnetic field and laser pulse on thermoelastic material with voids subjected to a laser pulse heating acting as a thermal shock. A comparison is also made between the two types (types II and III) of Green-Naghdi theory in the absence and the presence of the physical operators. Such problems are very important in many dynamical systems.
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Hatem Ibrahim, Bassma Aboukalloub and Reem Awwaad
The case of metropolitan Doha presents a unique study that has witnessed several transition phases in the urbanization process. It has embarked in massive urbanization processes…
Abstract
The case of metropolitan Doha presents a unique study that has witnessed several transition phases in the urbanization process. It has embarked in massive urbanization processes as part of the national planning vision. Nationals constitute 11% and expatriates constitute 89% of the total population of Qatar, which is environed by the government to manage the economic dynamism. Housing choice reflects the joint influences of government policies, housing market conditions, and personal factors such as housing preferences and the income level. The paper aims at studying housing choices for nationals and expatiates in metropolitan Doha through assessing the factors that limit housing choice for nationals and expatriates, providing policy recommendations to address the demand-supply gap in the market, and propose housing distribution in view of the developed housing choice framework. Three tools have been used: content analysis of reference data, questionnaire survey of housing preferences, and qualitative interview of experts' perceptions. This study has provided qualitative data on the issues of housing distribution and expansion in relation to housing choices. It has concluded baseline information for the nationals and expatriates housing distribution and the demographic dilemma.
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This study aims to examine whether chief executive officer (CEO) pay-performance sensitivity to shareholder wealth is related to the use of non-financial performance measures in…
Abstract
Purpose
This study aims to examine whether chief executive officer (CEO) pay-performance sensitivity to shareholder wealth is related to the use of non-financial performance measures in incentive contracts.
Design/methodology/approach
Using hand-collected performance measure data in a sample of S&P 500 firms across the period 1994–2010, this study investigates the sensitivity of CEO bonus and cash pay to shareholder wealth of firms that use non-financial performance (NFPM) measures of varying types and contractual weights in their bonus contracts along with financial measures (NFPM firms) in comparison to that of firms using financial measures only (FPM firms).
Findings
This study finds evidence that the pay-performance sensitivity is stronger in NFPM firms than in FPM firms. These results are driven by the use of CEO individual goals and operational efficiency. Furthermore, when using environmental, social and governance factors, the pay-performance sensitivity is stronger in terms of accounting performance only. This study also finds that using NFPM enhances pay-performance sensitivity more as their contractual weights increase and as financial risk increases.
Practical implications
These findings are important to stakeholders, and especially regulators in understanding incentive effects of alternative performance measures. This study also sheds light on what types of non-financial measures are better in helping firms align CEOs’ incentives to shareholders’ interests.
Originality/value
This study contributes to prior research on benefits of non-financial information within the context of executive compensation. This study presents original results about the effects of contractual weights of non-financial measures and financial risk on CEO pay-performance sensitivity. This study also presents new insights regarding how different types of non-financial measures affect CEO pay-performance sensitivity.
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Hamzah Elrehail, Ibrahim Harazneh, Mohammad Abuhjeeleh, Amro Alzghoul, Sakher Alnajdawi and Hussein M. Hussein Ibrahim
The purpose of this paper is to explore the impact of human resource (HR) management practices on achieving competitive advantage through studying the mediating role of employee…
Abstract
Purpose
The purpose of this paper is to explore the impact of human resource (HR) management practices on achieving competitive advantage through studying the mediating role of employee satisfaction in the context of five-star hotels in Northern Cyprus.
Design/methodology/approach
To produce numeric data as well as to test the hypothesis, the researchers employed structural equation modeling and AMOS. The testing included (n=439) questionnaires. The model suggested by the authors examined the tourism sector, and in particular, five-star hotels located in Northern Cyprus.
Findings
The main research findings revealed that HR practices had a significant effect on competitive advantage. By comparison, the research findings revealed that the mediator variable had no effect on achieving competitive advantage for five-star hotels in Northern Cyprus.
Originality/value
This study demonstrates originality by responding to the recommendations of prior studies conducted on HR in Northern Cyprus Island. This makes a theoretical contribution to the field, since only Turkey recognizes Northern Cyprus, which makes conducting research on this country a challenge for researchers worldwide. Based on this study’s outcomes, this paper discusses its theoretical and practical implications, as well as recommendations for future research.
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Issah Ibrahim, Mohammad Hossain Mohammadi, Vahid Ghorbanian and David Lowther
Acoustic noise is a crucial performance index in the design of electrical machines. Due to the challenges associated with modelling a complete motor, the stator is often used to…
Abstract
Purpose
Acoustic noise is a crucial performance index in the design of electrical machines. Due to the challenges associated with modelling a complete motor, the stator is often used to estimate the sound power in the prototyping stage. While this approach greatly reduces lengthy simulations, the actual sound power of the motor may not be known. But, from the acoustic noise standpoint, not much is known about the correlation between the stator and complete motor. This paper, therefore, aims to use the sound pressure levels of the stator and the full motor to investigate the existence of correlations in the interior permanent magnet synchronous motor.
Design/methodology/approach
A multiphysics simulation framework is proposed to evaluate the sound pressure levels of multiple motor geometries in a given design space. Then, a statistical analysis is performed on the calculated sound pressure levels of each geometry over a selected speed range to compare the correlation strength between the stator and the full model.
Findings
It was established that the stator and the complete motor model are moderately correlated. As such, a reliance on the stator sound power for design and optimization routines could yield inaccurate results.
Originality/value
The main contribution involves the use of statistical tools to study the relationship between sound pressure levels associated with the stator geometry and the complete electric motor by increasing the motor sample size to capture subtle acoustic correlation trends in the design space of the interior permanent magnet synchronous motor.
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