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Article
Publication date: 13 September 2011

A. Kapusta, A. Levy and B. Mikhailovich

The purpose of this paper is to determine technological potential of using multi‐frequency electromagnetic fields for the optimization of induction heating process.

Abstract

Purpose

The purpose of this paper is to determine technological potential of using multi‐frequency electromagnetic fields for the optimization of induction heating process.

Design/methodology/approach

The aim of the research is achieved by using phase‐modulated current feeding the solenoid that excites the magnetic field. In this case, the magnetic field, side by side with the carrier frequency, contains frequency spectrum arising due to modulation. At that, spectral components possess different penetration depths, which ensures a more uniform current density distribution over the cross‐section of the heated object. The results are obtained using theoretical analysis of electrodynamic and thermal processes in the heated body.

Findings

In the course of the work, a basic possibility of the objective realization is established, and its high enough efficiency is achieved using a sufficiently large range of modulation parameters.

Practical implications

The described method can significantly improve the technology of thermal treatment of metals and alloys liable to the formation of surface defects due to extreme temperature stresses.

Originality/value

The novelty of the paper consists in the use of phase‐modulated currents in induction heating.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 3 September 2018

Joanita Kataike, Durga Prasad Venkata Modekurti, Eric Butali, David Magumba, Andrew Ronnie Mugenyi, Adalbert Aine-Omucunguzi and Xavier Gellynck

Effective rural agribusiness development requires dedicated training programmes therefore, this paper is an attempt to investigate smallholder farmers’ TNs in the dairy…

Abstract

Purpose

Effective rural agribusiness development requires dedicated training programmes therefore, this paper is an attempt to investigate smallholder farmers’ TNs in the dairy agribusiness sector. The purpose of this paper is to study a bigger research project of the dairy value chain in agribusiness framework in the Rwenzori region.

Design/methodology/approach

A sample size of 100 dairy farmers were randomly selected from two Districts in the Rwenzori region. The descriptive statistics (mean and standard deviation) provided a basis for discussion. Furthermore, parametric Pearson coefficient test was conducted to examine the smallholder farmers’ TNs and assess its association with selected socio-demographic characteristics of the dairy farmers.

Findings

The analysis indicated that dairy farmers expressed the need for a training program. Most frequently requested topics include: fodder cultivation, quality and safe milk handling, milk marketing, calf feeding and rearing, animal nutrition and financial literacy out of 12 topics. The least desired TNs was record keeping.

Research limitations/implications

The findings contribute to the understanding of dairy farmers’ TNs.

Practical implications

The identified 12 key training intervention areas for the dairy farmers inform policymakers Dairy Development Authority and other development bodies in the Rwenzori region to address the challenges and improve smallholder dairy farming practices.

Originality/value

The study applies a synthesis review to identify theoretically acceptable variables that measure smallholder farmers’ TNs in the dairy agribusiness. The paper also shares the empirical evidence of a pioneering attempt to identify smallholder dairy farmers’ TNs in Uganda.

Details

Journal of Agribusiness in Developing and Emerging Economies, vol. 8 no. 3
Type: Research Article
ISSN: 2044-0839

Keywords

Article
Publication date: 1 July 2020

Wenchao Duan, Siqi Yin, Wenhong Liu, Jian Yang, Qingfeng Zhu, Lei Bao, Ping Wang, Jianzhong Cui and Zhiqiang Zhang

The purpose of this paper is to investigate the effect of pulsed magnetic field (PMF) with different duty cycles on the melt flow and heat transfer behaviors during direct-chill…

Abstract

Purpose

The purpose of this paper is to investigate the effect of pulsed magnetic field (PMF) with different duty cycles on the melt flow and heat transfer behaviors during direct-chill (DC) casting of large-size magnesium alloy billet and find the appropriate range of duty cycle.

Design/methodology/approach

A transient two-dimensional mathematical model coupled electromagnetic field, flow field and thermal field, is conducted to study the melt flow and temperature field under PMF and compared with that under the harmonic magnetic field.

Findings

The results reveal that melt vibration and fluctuation are generated due to the instantaneous impact of repeated thrust and pull effects of Lorentz force under PMF. The peak of Lorentz force decreases greatly with the increasing duty cycle, but the melt fluctuation region is expanded with higher duty cycle, which accelerates the interior melt velocity and reduces the temperature gradient at the liquid-solid interface. However, PMF with overly high duty cycle has adverse effect on the melt convection and limited influence on the interior melt. A duty cycle of 20% to 50% is a reasonable range.

Practical implications

This paper can provide guiding significance for the setting of duty cycle parameters on DC casting under PMF.

Originality/value

There are few reports on the effect of PMF parameters during DC casting with applying PMF, especially for duty cycle, a parameter unique to PMF. The findings will be helpful for applying the external field of PMF on DC casting.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 11 January 2022

Pradeep Vishnuram and Ramachandiran Gunabalan

Induction heating applications aided by power electronic control have become very attractive in the recent past. For cooking applications, power electronics circuits are very…

Abstract

Purpose

Induction heating applications aided by power electronic control have become very attractive in the recent past. For cooking applications, power electronics circuits are very suitable to feed power to multi loads with an appropriate control technique. The purpose of this paper is to develop a three leg inverter to feed power to three loads simultaneously and independently.

Design/methodology/approach

Pulse density modulation control technique is used to control the output power independently with constant switching frequency.

Findings

Multi-load handling converter with independent power control is achieved with reduced number of switching devices (two switches/per load) with simple control strategy.

Originality/value

The proposed system is simulated in MATLAB/Simulink, and the thermal analysis is carried out in COMSOL multi-physics software. The hardware realisation is performed for a 1 kW prototype with 20 kHz switching frequency and 10 kHz pulse density modulation frequency. PIC16F877A microcontroller is used to validate the experimental results for various values of control signals (DPDM). The simulation and experimental results are in good agreement and validates the developed system.

Article
Publication date: 31 January 2020

Andrey Morev and Alexander Aliferov

The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath.

Abstract

Purpose

The purpose of this paper is to investigate the effect of the rotating magnetic field of permanent magnets on the aluminium melt bath.

Design/methodology/approach

This model was developed in the ANSYS software package and is based on the application of the finite element method and finite volume.

Findings

The distribution of the velocity of the melt in a cylindrical vertical bath and the dependence of the maximum value of the melt displacement on the angular rotation velocity of the system of permanent magnets is obtained.

Originality/value

This work focusses on the interaction of the magnetic field of the moving magnets with the molten metal.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 12 March 2021

Sara Wilkinson, Marc Carmichael and Richardo Khonasty

The UN forecast of a 3-degree Celsius global temperature increase by 2,100 will exacerbate excessive heat. Population growth, urban densification, climate change and global…

Abstract

Purpose

The UN forecast of a 3-degree Celsius global temperature increase by 2,100 will exacerbate excessive heat. Population growth, urban densification, climate change and global warming contribute to heat waves, which are more intense in high-density environments. With urbanisation, vegetation is replaced by impervious materials which contribute to the urban heat island effect. Concurrently, adverse health outcomes and heat- related deaths are increasing, and heat stress affects labour productivity. More green infrastructure, such as green walls, is needed to mitigate these effects; however maintenance costs, OH&S issues and perceptions of fire risk inhibit take up. What if these barriers could be overcome by a green Wallbot? This research examines the feasibility of integrating smart technology in the form of a Wallbot.

Design/methodology/approach

The research design comprised two workshops with key stakeholders; comprising green wall designers and installers, green wall maintenance teams, project managers and building owners with green wall installations, horticulture scientists, designers and mechatronics engineers. The aim was to gain a deeper understanding of the issues affecting maintenance of green walls on different building types in New South Wales Australia to inform the design of a prototype robot to maintain green walls.

Findings

The Wallbot has great potential to overcome the perceived barriers associated with maintaining green walls and also fire risk and detection. If these barriers are addressed, other locations, such as the sides of motorways or rail corridors, could be used for more green wall installations thereby increasing mitigation of UHI. This innovation would be a welcome addition to smart building technology and property maintenance.

Research limitations/implications

This is a pilot study, and the sample of stakeholders attending the workshops was small, though experienced. The range of green walls is varied, and it was decided to focus initially on a specific type of green wall design for the prototype Wallbot. Therefore other types and sizes of green walls may suit other specifications of Wallbot design.

Practical implications

To date, no robot exists that maintains green walls, and this innovative research developed a prototype for trialling maintenance and inspection.

Originality/value

To date, no robot exists that maintains green walls. No study to date has assessed stakeholder perceptions and developed prototype Wallbot technology.

Details

Property Management, vol. 39 no. 4
Type: Research Article
ISSN: 0263-7472

Keywords

Article
Publication date: 7 July 2014

Katja Mikhailovich and Robert Fitzgerald

This paper aimed to examine the impact of the removal of bottled water on the campus community. This paper presents the findings of a survey conducted at the first Australian…

2331

Abstract

Purpose

This paper aimed to examine the impact of the removal of bottled water on the campus community. This paper presents the findings of a survey conducted at the first Australian university to remove single-use bottled water from sale on a small regional university campus. The removal of bottled water from sale at the university formed part of the university’s commitment to environmental sustainability.

Design/methodology/approach

The study was conducted substantially by undergraduate students who participated in an action learning project in which they assisted in the design, implementation and analysis of an online snapshot survey made available to all staff and students of the university.

Findings

The results indicated some evidence of changes to pro-environmental behaviors such as increased use of re-fillable bottles, but there were less desirable outcomes such as drinking less water. Community perceptions were dramatically polarized. Restrictions on freedom of choice, concerns about health as a result of increased use of high-sugar drinks and the continued availability of other plastic drink bottles were provided as strong objections to the removal of bottled water from sale on campus.

Practical implications

The study provides useful insights for university sustainability planners and administrators about the complex range of issues associated with the implementation of sustainability initiatives on a university campus.

Originality/value

While extensive literature exists about the environmental impacts of bottled water, few studies have explored the impacts or community responses to the removal of bottled water in the university context.

Details

International Journal of Sustainability in Higher Education, vol. 15 no. 3
Type: Research Article
ISSN: 1467-6370

Keywords

Article
Publication date: 7 April 2014

Marthe Deschesnes, Nathalie Drouin, Caroline Tessier and Yves Couturier

The purpose of this paper is to understand how a Canadian intervention based on a professional development (PD) model did or did not influence schools’ capacities to absorb a…

Abstract

Purpose

The purpose of this paper is to understand how a Canadian intervention based on a professional development (PD) model did or did not influence schools’ capacities to absorb a Healthy School (HS) approach into their operations. This study is the second part of a research project: previously published results regarding this research provided a detailed description of the PD model and highlighted the relevance and effectiveness of PD in improving actors’ HS-related knowledge and practices. The present paper focuses on the organizational impact of such PD intervention.

Design/methodology/approach

The design was based on a realist evaluation approach, which helps to elicit a theory explaining how an intervention leads to particular outcomes. A multi-site case study of three schools with pre- (T 0) and post- (T 1) intervention comparison was adopted. Multiple qualitative methods were used to capture how the changes were achieved by collecting data from various stakeholders involved in the intervention.

Findings

The PD model tested reinforced the schools’ capacities to absorb this type of initiative. For one of the capacities examined, “exploitation”, i.e., the ability to incorporate and maintain the initiative into schools operation, the evidence was less apparent. In congruence with the realist evaluation, the results are rendered in the form of a contextualized intervention theory identifying the links between the PD and the mechanisms that were likely necessary to explain what led to the changes in “absorptive” capacities (which refers to the capabilities of schools to acquire and assimilate HS knowledge, and also to transform and exploit them, in the context).

Originality/value

The refined theory, based on empirical findings, can enable facilitators and practitioners to gain a deeper understanding of the action mechanisms shown to be determining in the success of HS implementation.

Details

Health Education, vol. 114 no. 3
Type: Research Article
ISSN: 0965-4283

Keywords

Article
Publication date: 15 March 2013

Marthe Deschesnes, Nathalie Drouin and Yves Couturier

A comprehensive “health promoting schools” (HPS) approach is advocated by the World Health Organization to foster the health of students. To date, few studies have evaluated…

Abstract

Purpose

A comprehensive “health promoting schools” (HPS) approach is advocated by the World Health Organization to foster the health of students. To date, few studies have evaluated schools' capacity to implement it in an optimal way. The purpose of this paper is to present a conceptual framework that identifies core features likely to facilitate the incorporation of innovation, such as HPS, into school functioning.

Design/methodology/approach

The framework was built by combining dimensions derived from two major strands of literature, i.e. management and HPS. It has taken root in Zahra and George's model of organisation absorptive capacity (AC) for new knowledge but has been adapted to better explore AC in a school context. The contrasting cases of two secondary schools that adopted a HPS approach in Quebec, Canada, for at least three years were used to illustrate the value of the framework.

Findings

The framework proposed is a multidimensional model that considers components such as modulators, antecedents, integration mechanisms and strategic levers as potential determinants of AC, i.e. acquisition, assimilation, transformation and exploitation. The conceptual framework helped to qualify and compare AC regarding HPS in the two cases and holds promise to appreciate mechanisms having the greatest influence on it.

Originality/value

The framework can serve as a conceptual guide to facilitate the absorption of innovation in schools and to design future empirical research to better understand the underlying process by which schools strengthen their capacities to become settings conducive to the health of youth.

Details

Journal of Health Organization and Management, vol. 27 no. 1
Type: Research Article
ISSN: 1477-7266

Keywords

Article
Publication date: 3 February 2020

Sikander Hans and Smarajit Ghosh

The efficient speed controller is found to be an important requirement to run the motor for the brushless direct current (BLDC) motor. This requirement is considered as superior…

Abstract

Purpose

The efficient speed controller is found to be an important requirement to run the motor for the brushless direct current (BLDC) motor. This requirement is considered as superior, as it may increase the operating speed and system efficiency. In the existing methods, proportional plus integral (PI) controller has been included because of its simple architecture. But the PI controller produces load disturbance, control complexity and some parametric (Proportional plus integral) variations. The purpose of this proposed controller is to overcome the problems produced by PI controller in BLDC motor.

Design/methodology/approach

The proposed BLDC motor is developed with fixed order H-infinity controller. In this architecture, both the weight functions and transfer functions were included to design the controller. This controller has been included in this BLDC to detect the rotor position. The optimal position of rotor is identified by introducing particle swarm optimization algorithm.

Findings

The torque that obtained in the motor is highly reduced by this proposed controller and also enhances the speed. The BLDC motor is modelled in a MATLAB environment.

Practical implications

The performance of the torque, speed and back electro-motive force is analysed and compared with the existing controllers such as fuzzy proportional plus integral plus derivative, sensing algorithm and fuzzy proportional plus derivative controller.

Originality/value

Simulation results show that the proposed technique gives better results than the other existing controllers.

1 – 10 of 20