Yahia Achour and Jacek Starzyński
This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of…
Abstract
Purpose
This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of a working design.
Design/methodology/approach
The authors replace the primary winding of the transformer with a capacitor. The displacement current between the capacitor plates induces a magnetic flux in the core. This flux in turn induces electromotive force in the classical secondary winding.
Findings
The basic mathematical aspects illustrated by results obtained from a simulation developed using a commercial software ANSYS-HFSS are given. The saturation of the magnetic core due to the applied high-frequency range is investigated and simulated using a finite difference time domain code implemented in MATLAB. A prototype transformer was built and tested; the obtained results confirm the previous ones from simulations.
Originality/value
A new concept of the single winding transformer was used as a pulse forming circuit.
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Keywords
Brahim Nécira and Yacine Abadou
By its high fluidity, great deformability and rheological stability, the self-compacting mortar (SCM) is capable of ensuring the ability to be easily implemented without…
Abstract
Purpose
By its high fluidity, great deformability and rheological stability, the self-compacting mortar (SCM) is capable of ensuring the ability to be easily implemented without vibration. However, its formulation requires a large volume of fine materials with a high dosage of cement, which is necessary to ensure adequate workability and mechanical strengths, which is necessary to allow its flow. Current environmental considerations encourage reducing the production of cement, it is essential to use additions to replace the cement, because of their great availability and their moderate price. On another side, their use contributes to an economic sort to solve the problems related to the environment.
Design/methodology/approach
The formulations and characteristics of SCM made with two types of mineralogical sources (silica and limestone) were investigated. Different materials were used separately and in binary combinations; silica river sand (SRS), limestone quarry sand (LQS), silica fillers (SF) and limestone fillers (LF). The formulation starts with the self-compacting pastes (SCPs) then the SCMs at the SRS and the LQS whose the cement is partially replaced by volume contents of SF and LF with 15%, 30% and 45%.
Findings
The results obtained prove that the incorporation of LQS instead of SRS has a negative effect on the fluidity and deformability and a positive effect on the mechanical strengths of SCM. In addition, the incorporation of the SF and LF reduces the need for water and the saturation dose of superplasticizer in the pastes. Thus, the addition of the SF and LF in specific voluminal contents (15% SF and 30% LF) in the binder can have a beneficial effect on the parameters of the workability and the mechanical strengths of SCM. These results are very interesting to aspects such as technological, economic and environmental.
Originality/value
Influence of the different type of sands and fillers in improvements the properties of SCM made from various mineralogical sources.
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Sarra Berraies, Rym Lajili and Rached Chtioui
The objective of this research is to examine the mediating role of employees' well-being in the workplace in the relationship between the dimensions of social capital, namely…
Abstract
Purpose
The objective of this research is to examine the mediating role of employees' well-being in the workplace in the relationship between the dimensions of social capital, namely structural, relational and cognitive social capital and knowledge sharing, as well as the moderating role of enterprise social networks between knowledge sharing and employees' well-being.
Design/methodology/approach
A quantitative approach was performed within a sample of 168 middle managers working in knowledge-intensive firms in Tunisia. The Partial Least Squares method was used to analyze the data collected.
Findings
Results highlight the importance of the dimensions of social capital as a lever for boosting knowledge sharing. It also reveals that employees' well-being plays a mediating role in the link between structural and relational social capital and knowledge sharing. Moreover, findings show that while enterprise social networks use does not moderate the relationship between employees' well-being and knowledge sharing, it has a positive and significant effect on knowledge sharing.
Originality/value
On the basis of a socio-technical perspective of knowledge management, this research pioneers the examination of the mediating effect of employees' well-being in the link between dimensions of social capital and knowledge sharing and the moderating role of enterprise social networks use within knowledge-intensive firms. Findings of this study may help managers of knowledge-intensive firms in boosting knowledge sharing within organizations, in improving knowledge workers' well-being and thus in motivating and retaining these talented employees.
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Sarra Berraies, Khadija Aya Hamza and Rached Chtioui
The aim of this paper is to highlight the impact of distributed leadership (DL) on exploitative and exploratory innovations through the mediating effects of organizational trust…
Abstract
Purpose
The aim of this paper is to highlight the impact of distributed leadership (DL) on exploitative and exploratory innovations through the mediating effects of organizational trust (OT) and tacit and explicit knowledge sharing (KS).
Design/methodology/approach
Focusing on a quantitative approach, an empirical study was performed within a sample of information and communication technology Tunisian firms. The data collected was analyzed through the Partial Least Squares (PLS) method.
Findings
Findings revealed that DL is a driver of tacit and explicit KS, and exploitative and exploratory innovations. It also highlighted that tacit KS is associated with these two types of innovation. In this line, results showed that tacit KS plays a mediating effect between DL and exploitative and exploratory innovations. Moreover, our research highlighted that DL has a positive impact on OT that in turn boosts tacit and explicit KS.
Originality/value
This paper investigates the links between DL and exploitative and exploratory innovations within knowledge intensive firms (KIFs) that have never been studied in the literature within the context of business firms. This paper pioneers the examination of the mediating roles of explicit and tacit KS and OT in these links as well. This paper highlights the importance of DL for KIFs and sheds the light on how this collectivist approach of leadership creates an atmosphere of trust and fosters tacit and explicit KS to boost exploitative and exploratory innovations.
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Guo Chen, Mohamed Wahab Mohamed Ismail and Liping Fang
The single-supplier multi-retailer cold chain is a widely adopted type of supply chain in the real-world food industry. This paper aims to consider the problem of effectively…
Abstract
Purpose
The single-supplier multi-retailer cold chain is a widely adopted type of supply chain in the real-world food industry. This paper aims to consider the problem of effectively designing and managing a single-supplier multi-retailer cold chain for fresh produce with deterministic demand to minimize the total cost, which includes cooling, loss of value and carbon emission costs.
Design/methodology/approach
The global stability index (GSI) method and the non-Arrhenius model are integrated to describe the behavior of food quality degradation. The power-of-two (PoT) policy is adopted in determining the coordinated replenishment policies for the suppliers and retailers, and an appropriate wholesale price structure that can achieve the coordination of the chain is presented.
Findings
The properties of the cold chain are uncovered, and an appropriate wholesale price scheme that achieves chain coordination with the optimal PoT decision is provided. In the numerical examples, different scenarios are investigated, and it is found that the cold chain parameters influence the optimal decisions in certain ways.
Originality/value
The PoT policy – an efficient policy to determine the replenishment strategy – has not been adopted in finding the solution of a single-supplier multi-retailer cold chain in the literature. Also, no study has compared the uncoordinated and coordinated cold chain. Moreover, in the existing literature, the wholesale price is usually a constant rather than having a coordinated scheme. This research aims to fill these research gaps.