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1 – 5 of 5Hajer Jmal, Amal Souissi and Imen Abdennadher
This paper aims to an analytical investigation of a consequent poles (CP) permanent magnet machine, to enhance the accuracy of the predicted air gap flux density and thus of the…
Abstract
Purpose
This paper aims to an analytical investigation of a consequent poles (CP) permanent magnet machine, to enhance the accuracy of the predicted air gap flux density and thus of the machine performance.
Design/methodology/approach
The machine under study is obtained by the substitution of the poles machines (PMs) that corresponds to south poles, of a conventional surface PM (SPM) machine, by iron pieces of same geometry. First, the analytical model of the air gap flux density generated by a SPM topology is presented. To fit the CP concept, such model has been rearranged based on a virtual SPM machine. Then, an improved prediction of the CP machine air gap flux density is addressed by the incorporation of a south pole rotor correction function.
Findings
An improved prediction of the consequent pole PM machines air gap flux density is addressed by the incorporation of a south pole rotor correction function.
Originality/value
The paper proposes an original approach to enhance the prediction of the air gap flux density of consequent pole machines despite the different magnetic permeability of the north and south poles.
Details
Keywords
Anis Abdelkefi, Amal Souissi and Imen Abdennadher
This paper aims at the analytical formulation of the electromagnetic features of flux switching permanent magnet (PM) machines with emphasis on the PM air gap flux density and…
Abstract
Purpose
This paper aims at the analytical formulation of the electromagnetic features of flux switching permanent magnet (PM) machines with emphasis on the PM air gap flux density and armature magnetic reaction.
Design/methodology/approach
The PM air gap flux density is formulated considering three different analytical models. These differ by the incorporation of the air gap magnetic saliency level from the stator side. In addition, the armature magnetic reaction is investigated based on a simplified magnetic reluctance circuit that considers the flux switching permanent magnet machines magnetic circuit geometry specification. Then, the no- and on-load torque is predicted based on the two air gap flux densities.
Findings
It has been found that the PM air gap flux density considering the stator saliencies with trapezoidal magnetomotive force waveform presents the highest accuracy. Despite the simplicity of the magnetic equivalent circuit-based approach, the predicted air gap armature magnetic reaction is in good agreement with the finite element analysis (FEA) one. These lead to the analytical predictions of the no- and on-load torque which is characterized by an acceptable accuracy.
Research limitations/implications
This work should be extended to experimental validation of the FEA results regarding the torque production generation.
Originality/value
The paper proposes an improved design-oriented analytical approach with emphasis on the PM air gap flux density and the armature magnetic reaction of flux switching PM machines.
Details
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Mohamed Wael Zouaghi, Amal Souissi, Imen Abdennadher and Ahmed Masmoudi
The purpose of this paper is to deal with the investigation of no-load operation of tubular linear permanent magnet synchronous machines (T-LPMSMs). It is aimed at the prediction…
Abstract
Purpose
The purpose of this paper is to deal with the investigation of no-load operation of tubular linear permanent magnet synchronous machines (T-LPMSMs). It is aimed at the prediction of the phase flux linkages, the back-EMF and the cogging force using a position varying magnetic equivalent circuit (MEC).
Design/methodology/approach
This study is based on the elaboration and the resolution of the position varying MEC, and the utilization of its results for the prediction of the phase flux linkages, the back-EMF and the cogging force, considering a general topology of T-LPMSMs. Then, a case study is treated with a position varying MEC-based investigation of its no-load features. These are validated by a 2-D finite element analysis (FEA).
Findings
It has been found that the developed position varying MEC can be regarded as an accurate tool that requires a low CPU-time.
Research limitations/implications
Beyond the FEA validation, this work should be extended to an experimental one. Moreover, the position varying MEC validity should be extended to load operation in order to enable the prediction of the force production capability.
Practical implications
The developed position varying MEC could be suitably used for the pre-design of T-LPMSMs. These are currently given an increasing attention in many applications, such as wave energy conversion and free-piston engines.
Originality/value
The paper proposes a position varying MEC for the prediction of the features of T-LPMSMs.
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Amal Yamani, Khaled Hussainey and Khaldoon Albitar
This study aims to investigate the impact of financial instrument disclosures under the International Financial Reporting Standard (IFRS) 7 on the cost of equity capital (COEC).
Abstract
Purpose
This study aims to investigate the impact of financial instrument disclosures under the International Financial Reporting Standard (IFRS) 7 on the cost of equity capital (COEC).
Design/methodology/approach
The sample consists of 56 banks listed in the Gulf cooperation council (GCC) stock markets over 7 years from 2011 to 2017. A self-constructed index is used to measure the compliance level in addition to quantitative methods and panel data regression adopted to test the research hypotheses.
Findings
The authors find that the compliance level with IFRS 7 does not improve from 2011 until 2017 in the GCC banks. The authors also find that compliance with IFRS 7 disclosures reduces the COEC.
Originality/value
The authors also provide new empirical evidence that the level of mandatory financial instruments disclosures under IFRS 7 reduces the COEC. The findings offer policy implications. It shows that compliance with IFRS 7 disclosure requirements leads to desirable economic consequences.
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Amal Hamrouni, Ali Uyar and Rim Boussaada
The purpose of this paper is to test whether or not CSR disclosure (i.e. aggregate as well as its three sub-indicators) reduces the cost of debt for French corporations listed in…
Abstract
Purpose
The purpose of this paper is to test whether or not CSR disclosure (i.e. aggregate as well as its three sub-indicators) reduces the cost of debt for French corporations listed in the SBF 120 index between 2010 and 2015.
Design/methodology/approach
CSR disclosure ratings of firms were collected from the Bloomberg database under three dimensions such as environmental, social and governance (ESG). Then, a pooled regression analysis was run.
Findings
The results indicate that overall CSR disclosure score as a combination of ESG disclosure scores has a negative effect on the cost of debt (i.e. lowers the cost of debt). While environmental disclosure is negatively associated with the cost of debt, social disclosure is unexpectedly positively associated, and governance disclosure has an insignificant association with the cost of debt.
Research limitations/implications
The study has two main limitations. First, the analysis does not consider contractual constraints and obligations that might exist in debt contracts (Jung et al., 2018). Second, the analyses cover a specific time period (i.e. between 2010 and 2015) for a specific country (i.e. France) excluding utilities and the financial sector.
Practical implications
Overall, it is inferred from the results that financial markets for lenders take into account CSR disclosure when assessing the creditworthiness of borrowers. Specifically, environmental disclosure is the only subdimension of CSR that is influential on creditors’ decisions to offer favorable interest rates. In line with this outcome, companies can assess their processes and be more aligned with eco-friendly practices, and investors are particularly advised to invest in those types of firms.
Originality/value
This study extends scant literature on the association between CSR and the cost of debt by exploring how creditors treat CSR dimensions dissimilarly in granting loans to firms. The findings of this study have particular importance as financial debt is one of the most predominant forms of external financing.
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