Search results

1 – 10 of 335
To view the access options for this content please click here
Article
Publication date: 7 July 2020

Wasiq Ullah, Faisal Khan and Muhammad Umair

The purpose of this paper is to investigate an alternative simplified analytical approach for the design of electric machines. Numerical-based finite element method (FEM…

Abstract

Purpose

The purpose of this paper is to investigate an alternative simplified analytical approach for the design of electric machines. Numerical-based finite element method (FEM) is a powerful tool for accurate modelling and electromagnetic performance analysis of electric machines. However, computational complexity, magnetic saturation, complex stator structure and time consumption compel researchers to adopt alternate analytical model for initial design of electric machine especially flux switching machines (FSMs).

Design/methodology/approach

In this paper, simplified lumped parameter magnetic equivalent circuit (LPMEC) model is presented for newly developed segmented PM consequent pole flux switching machine (SPMCPFSM). LPMEC model accounts influence of all machine parts for quarter of machine which helps to reduce computational complexity, computational time and drive storage without affecting overall accuracy. Furthermore, inductance calculation is performed in the rotor and stator frame of reference for accurate estimation of the self-inductance, mutual inductance and dq-axis inductance profile using park transformation.

Findings

The developed LPMEC model is validated with corresponding FEA using JMAG Commercial FEA Package v. 18.1 which shows good agreement with accuracy of ∼98.23%, and park transformation precisely estimates the inductance profile in rotor and stator frame of reference.

Practical implications

The model is developed for high-speed brushless AC applications.

Originality/value

The proposed SPMCPFSM enhance electromagnetic performance owing to partitioned PMs configuration which make it different than conventional designs. Moreover, the developed LPMEC model reduces computational time by solving quarter of machine.

To view the access options for this content please click here
Article
Publication date: 11 January 2019

Abdul Hameed, Syed Asif Raza, Qadeer Ahmed, Faisal Khan and Salim Ahmed

The purpose of this paper is to develop a decision support tool for risk-based maintenance scheduling for a large heavily equipped gas sweetening unit in a Liquefied…

Abstract

Purpose

The purpose of this paper is to develop a decision support tool for risk-based maintenance scheduling for a large heavily equipped gas sweetening unit in a Liquefied Natural Gas (LNG) plant. Two conflicting objectives, i.e., total maintenance cost and the reliability, are considered in the tool. The tool is tested with the real plant data and suggests several Pareto-optimal schedules for a decision maker to choose from. The financial impacts are assessed.

Design/methodology/approach

A bi-objective scheduling optimization model is developed for maintenance scheduling using a risk-based framework. The model is developed integrating genetic algorithm and simulation-based optimization to find Pareto-optimal schedules. The model delivered true Pareto front optimal solutions for given plant-specific data. The two conflicting objectives: the minimization of total expenditures incurred on maintenance-related activities and improving the total reliability are considered.

Findings

For large and complex processing facilities such as LNG plant, a shutdown of facility generates a significant financial impact, resulting in millions of dollars in production loss. The developed risk-based equipment selection strategy helps to minimize such an event of production loss by generating a thorough maintenance strategy for inspection, repair, overhaul or replacement schedule of the unit without initiating the shutdown. The proposed model has been successfully applied to obtain an optimize maintenance schedule for a gas sweetening unit.

Research limitations/implications

A future work may consider the state-dependent models for various failure modes that will result in obtaining a better representation of the model. The proposed scheduling can further be extended to multi-criteria scheduling including availability, resource limitation and inflationary condition. A comparative analysis with other meta-heuristic techniques such as harmony search algorithm, tabu search, and simulated annealing will further help in confirming the schedule obtained from this application.

Practical implications

Maintenance scheduling using a conventional approach for special equipment generally does not consider the conflicting objectives. This research addresses this aspect using a bi-objective model. The usefulness of risk-based method is to assist in minimizing the financial and safety risk exposure to the operating companies, but some variation in results is expected due to varying risk matrix for different organizations.

Social implications

Managing two objectives, i.e., minimizing the cost of maintenance-related activities, while at the same time maximizing the overall reliability dramatically, helps in mitigating adverse safety and financial risk due to fires, explosions, fatality and excessive maintenance cost.

Originality/value

Research develops a decision support tool for managing conflicting objectives for an LNG process. This research highlights the impact of utilizing the simulation-based approach coupled with risk-based equipment selection for complex processing unit or plant maintenance scheduling optimization.

Details

Journal of Quality in Maintenance Engineering, vol. 25 no. 1
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 11 October 2020

Muhammad Umair, Faisal Khan and Wasiq Ullah

Field excited flux switching machines (FEFSM) are preferred over induction and synchronous machines due to the confinement of all excitation sources on the stator leaving…

Abstract

Purpose

Field excited flux switching machines (FEFSM) are preferred over induction and synchronous machines due to the confinement of all excitation sources on the stator leaving a robust rotor. This paper aims to perform coupled electromagnetic thermal analysis and stress analysis for single phase FEFSM as, prolonged high-speed operational time with core and copper losses makes it prone to stress and thermal constraints as temperature rise in machine lead to degraded electromagnetic performance whereas the violation of the principle stress limit may result in mechanical deformation of the rotor.

Design/methodology/approach

This paper presents the implementation of coupled electromagnetic-thermal and rotor stress analysis on single-phase FEFSM with non-overlap winding configurations using finite element analysis (FEA) methodology in JMAG V. 18.1. three-dimensional (3D) magnetic loss analysis is performed and extended to 3D thermal analysis to predict temperature distribution on various parts of the machine whereas Stress analysis predicts mechanical stress acting upon edges and faces of the rotor.

Findings

Analysis reveals that temperature distribution and rotor stress on the machine is within acceptable limits. A maximum temperature rise of 37.7°C was noticed at armature and field windings, temperature distribution in stator near pole proximity was 35°C whereas no significant change in rotor temperature was noticed. Furthermore, principal stress at the speed of 3,000 rpm and 30,000 rpm was found out to be 0.0305 MPa 3.045 MPa, respectively.

Research limitations/implications

The designed machine will be optimized for improvement of electromagnetic performance followed by hardware implementation and experimental testing in the future.

Practical implications

The model is developed for axial fan applications.

Originality/value

Thermal analysis is not being implemented on FEFSM for axial fan applications which is an important analysis to ensure the electromagnetic performance of the machine.

Details

World Journal of Engineering, vol. 17 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Article
Publication date: 3 October 2016

Faisal Khan, Erwan Sulaiman, Hassan Ali Soomro, Fairoz Omar and Zarafi Ahmad

The paper aims to propose and compare two new structures of a three-phase wound field salient rotor (WFSR) switched-flux motor (SFM) with 24 stator slots and 10 or 14…

Abstract

Purpose

The paper aims to propose and compare two new structures of a three-phase wound field salient rotor (WFSR) switched-flux motor (SFM) with 24 stator slots and 10 or 14 rotor poles, respectively, for high-speed operation.

Design/methodology/approach

The paper outlines the motor general construction and design concept of proposed machines. Flux linkage, average torque, rotor mechanical strength and torque–speed characteristics of both machines were analyzed and compared by two-dimensional finite element analysis (2D-FEA). Deterministic optimization method was adopted to enhance the characteristics of 24Slot-10Pole WFSR SFM.

Findings

The paper provides simulation results and discusses how 24Slot-10Pole WFSR SFM structure is superior to the 24Slot-14Pole in the aspects of flux linkage, average torque and power. It further concludes that the optimized design of 24Slot-10P has achieved 58 and 72 per cent higher average torque and power compared to initial design, as well as high average torque and power compared to 24Slot-14P design.

Originality value

Optimized structure of the 24Slot-10Pole WFSR SFM with non-overlapping windings has been proposed.

Details

World Journal of Engineering, vol. 13 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Case study
Publication date: 30 December 2019

Meenakshi Sharma

The case deals with Axel Motor's expansion into India and the clash between expectations and communication styles of the Indian subsidiary and Headquarters. While the…

Abstract

The case deals with Axel Motor's expansion into India and the clash between expectations and communication styles of the Indian subsidiary and Headquarters. While the subsidiary wants to follow a responsive, market-driven approach to product design and marketing strategy, the top management is driven by the strong belief that the group's core values are universal and no tweaking is needed for particular locations. Anil Mishra, Head of Sales, and the team at the corporate office of Axel Motors India have received an email from Maximilian Klotz, Head of Strategy at Axel Motor's Headquarters. Klotz has expressed complete dissatisfaction with the performance of Axel Motors India. Mishra and the team have to decide how to handle the challenge of getting their input - based on an understanding of the local environment - valued at Headquarters.

Details

Indian Institute of Management Ahmedabad, vol. no.
Type: Case Study
ISSN: 2633-3260
Published by: Indian Institute of Management Ahmedabad

Keywords

To view the access options for this content please click here
Article
Publication date: 12 September 2016

Mohd. Nishat Faisal and Habibullah Khan

U-commerce is an emerging paradigm transcending traditional e-commerce boundaries. The purpose of this paper is to highlight those issues that deserve attention in…

Abstract

Purpose

U-commerce is an emerging paradigm transcending traditional e-commerce boundaries. The purpose of this paper is to highlight those issues that deserve attention in developing successful u-commerce models.

Design/methodology/approach

The interpretive structural model technique is adopted to construct a hierarchical structure, and the impact matrix cross-reference multiplication applied to a classification (MIC-MAC) approach is employed to analyze the effect and dependence among these factors.

Findings

The research shows that there exists a group of enablers having a high driving power and low dependence requiring maximum attention and of strategic importance, while another group consists of those variables that have high dependence and are the resultant actions.

Practical implications

Organizations that plans to develop a u-commerce model would be benefited from this study. They can understand the difference between the independent and dependent variables and their mutual relationships. This would help them to prioritize their budget and implement suitable strategies to cater to key variables so as to exploit the benefits of u-commerce.

Social implications

Most of the GCC countries have very similar business environment. This research can easily be adapted to other GCC nations thereby saving the duplication of time, efforts and money.

Originality/value

This research was conducted in a developing economy in a GCC country which is very fast adopter of new technology. The findings of this study would serve as a guide to the businesses who are migrating to a u-commerce model in future.

Details

International Journal of Productivity and Performance Management, vol. 65 no. 7
Type: Research Article
ISSN: 1741-0401

Keywords

To view the access options for this content please click here
Expert briefing
Publication date: 25 April 2016

These plans have intensified pressure on Prime Minister Nawaz Sharif, who has been implicated, together with his family, in the Panama papers. In parallel, the military…

To view the access options for this content please click here
Article
Publication date: 9 March 2015

Mohamed Khalifa, Faisal Khan and Joseph Thorp

– The purpose of this paper is to propose a quantitative model for risk-based maintenance and remaining life assessment for gas turbines.

Abstract

Purpose

The purpose of this paper is to propose a quantitative model for risk-based maintenance and remaining life assessment for gas turbines.

Design/methodology/approach

The proposed model uses historical failure and repair data from the operation of gas turbines. The time to failure of gas turbines is modeled using Weibull distribution.

Findings

The total risk is estimated considering replacement cost, repair cost, operation cost, risk of failure and turbine remaining value after a specified period of time.

Originality/value

The model is an effective tool to make optimal decisions regarding maintenance strategy (repair or replacement) and to assess the remaining life based on a comparison of the total risk. The literature review focusses on developing different models to make risk-based decisions regarding the selection of a maintenance strategy and maintenance interval, however, literature is silent regarding risk-based assessment of the equipment remaining life, which is the focus of present work. The model is tested and applied to ageing gas turbines in a cross-country pipeline.

Details

Journal of Quality in Maintenance Engineering, vol. 21 no. 1
Type: Research Article
ISSN: 1355-2511

Keywords

To view the access options for this content please click here
Article
Publication date: 3 May 2011

Vinita P. Ambwani, Louise Heslop and Lorraine S. Dyke

The purpose of this paper is to identify and explain barriers to differentiation for minority focused advertising agencies and propose modification to the existing…

Abstract

Purpose

The purpose of this paper is to identify and explain barriers to differentiation for minority focused advertising agencies and propose modification to the existing framework of agency selection process.

Design/methodology/approach

Multiple semi‐structured, in‐depth interviews were conducted with key industry personnel. The data from these were augmented with proprietary research conducted by the relevant organizations and extensive review of the literature.

Findings

Few advertising agencies differentiate themselves by specializing in campaigns targeting minority populations. Several barriers to differentiation exist which can be explained using Institutional Theory and Economic Detour Theory. Rational Goal model and the Learning and Effectiveness Paradigm of diversity are used to suggest modification to current approaches.

Research limitations/implications

Future studies should test the validity of the proposed framework.

Practical implications

The proposed framework for agency selection will lead to differentiation opportunities for advertising agencies and potential business for clients.

Originality/value

The paper identifies the theoretical drivers of the barriers that exist for minority focused advertising agencies. The modified framework proposed uses theoretical rationale to addresses these barriers.

Details

Equality, Diversity and Inclusion: An International Journal, vol. 30 no. 4
Type: Research Article
ISSN: 2040-7149

Keywords

To view the access options for this content please click here
Article
Publication date: 1 November 2006

Rehan Sadiq and Faisal I. Khan

This paper proposes an integrated methodology for process design to guide decision making under uncertainty by combining life cycle assessment (LCA) with multi‐criteria…

Abstract

Purpose

This paper proposes an integrated methodology for process design to guide decision making under uncertainty by combining life cycle assessment (LCA) with multi‐criteria decision‐making tools.

Design/methodology/approach

Cleaner and greener technologies for process and product selection and design have gained popularity in recent years. The LCA is a systematic approach that enables selection of cleaner and greener products and processes. Recently, significant progress has been made for the use of LCA for product/process evaluation and selection. However, its use in process design and environmental decision making has not been fully exploited. The proposed methodology GreenPro‐I is a systematic approach to estimate environmental risks/impacts associated with life cycle of products, processes and services. It evaluates environmental burdens by quantifying energy and materials used and waste released into the environment. It identifies and evaluates opportunities, which affect environmental improvements. The assessment includes the extraction/excavation and processing of raw materials, manufacturing, transportation and distribution, use, recycle, and final disposal.

Findings

GreenPro‐I overcomes many of the problems faced in the conventional approaches and establishes a link between the environmental risks/impacts, cost, and technical feasibility of processes.

Originality/value

GreenPro‐I provides a comprehensive decision‐making tool for designers, regulatory agencies, business organizations and other stakeholders.

Details

Business Process Management Journal, vol. 12 no. 6
Type: Research Article
ISSN: 1463-7154

Keywords

1 – 10 of 335