David A. Lowther, Behzad Forghani and Uday Deshpande
Two‐ and three‐dimensional computations of the cogging torque in a brushless dc motor are compared with measurements for both skewed and unskewed stators. The modeling of stator…
Abstract
Two‐ and three‐dimensional computations of the cogging torque in a brushless dc motor are compared with measurements for both skewed and unskewed stators. The modeling of stator skew is considered both using a full three dimensional model with and without material anisotropy and using a set of displaced two‐dimensional slices. The errors inherent in the latter approach are discussed. A cost/benefit trade‐off between three‐dimensional and two‐dimensional analyses is considered.
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Quality management among multiple business units of a large organization is often difficult if each unit is run independently in terms on their quality standards. In this case…
Abstract
Quality management among multiple business units of a large organization is often difficult if each unit is run independently in terms on their quality standards. In this case, participants will discuss how Bukhari Group of Companies should establish a common brand image through standardized quality. Participants should also understand that common brand image for diverse products does not mean identical level of rejection or customer complaints. It should be understood that different markets have different tolerance for product failures. The participants can chalk out the measures the protagonist of the case should be able to take to effectively steer the Bhukari Group to achieve profits and excellence.
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Alireza Ahmadi, Peter Söderholm and Uday Kumar
The purpose of this paper is to present issues and challenges of scheduled maintenance task development within the maintenance review board (MRB) process, and to find potential…
Abstract
Purpose
The purpose of this paper is to present issues and challenges of scheduled maintenance task development within the maintenance review board (MRB) process, and to find potential areas of improvement in the application of the MSG‐3 methodology for aircraft systems.
Design/methodology/approach
The issues and challenges as well as potential areas of improvement have been identified through a constructive review that consists of two parts. The first part is a benchmarking between the Maintenance Steering Group (MSG‐3) methodology and other established and documented versions of reliability‐centred maintenance (RCM). This benchmarking focuses on the MSG‐3 methodology and compares it with some RCM standards to identify differences and thereby find ways to facilitate the application of MSG‐3. The second part includes a discussion about methodologies and tools that can support different steps of the MSG‐3 methodology within the framework of the MRB process.
Findings
The MSG‐3 methodology is closely related to the RCM methodology, in which the anticipated consequences of failure are considered for risk evaluation. However, MSG‐3 considers neither environmental effects of failures nor operational consequences of hidden failures. Furthermore, in MSG‐3, the operational check (failure‐finding inspection) is given priority before all other tasks, whereas in RCM it is considered as a default action, where there is no other applicable and effective option. While RCM allows cost‐effectiveness analysis for all failures that have no safety consequences, MSG‐3 just allows it for failures with economic consequences. A maintenance program that is established through the MRB process fulfils the requirements of continuous airworthiness, but there is no foundation to claim that it is the optimal or the most effective program from an operator's point‐of‐view. The major challenge when striving to achieve a more effective maintenance program within the MRB process is to acquire supporting methodologies and tools for adequate risk analysis, for optimal interval assignments, and for selection of the most effective maintenance task.
Originality/value
The paper presents a critical review of existing aircraft scheduled maintenance program development methodologies, and demonstrates the differences between MSG‐3 and other RCM methodologies.
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Srinivas Rao Sriram, Saidireddy Parne, Venkata Satya Chidambara Swamy Vaddadi, Damodar Edla, Nagaraju P., Raji Reddy Avala, Vijayakumar Yelsani and Uday Bhasker Sontu
This paper aims to focus on the basic principle of WO3 gas sensors to achieve high gas-sensing performance with good stability and repeatability. Metal oxide-based gas sensors are…
Abstract
Purpose
This paper aims to focus on the basic principle of WO3 gas sensors to achieve high gas-sensing performance with good stability and repeatability. Metal oxide-based gas sensors are widely used for monitoring toxic gas leakages in the environment, industries and households. For better livelihood and a healthy environment, it is extremely helpful to have sensors with higher accuracy and improved sensing features.
Design/methodology/approach
In the present review, the authors focus on recent synthesis methods of WO3-based gas sensors to enhance sensing features towards toxic gases.
Findings
This work has proved that the synthesis method led to provide different morphologies of nanostructured WO3-based material in turn to improve gas sensing performance along with its sensing mechanism.
Originality/value
In this work, the authors reviewed challenges and possibilities associated with the nanostructured WO3-based gas sensors to trace toxic gases such as ammonia, H2S and NO2 for future research.
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Mohd Atif Siddiqui, Md Nishat Anwar and Shahedul Haque Laskar
This paper aims to present an efficient and simplified proportional-integral/proportional-integral and derivative controller design method for the higher-order stable and…
Abstract
Purpose
This paper aims to present an efficient and simplified proportional-integral/proportional-integral and derivative controller design method for the higher-order stable and integrating processes with time delay in the cascade control structure (CCS).
Design/methodology/approach
Two approaches based on model matching in the frequency domain have been proposed for tuning the controllers of the CCS. The first approach is based on achieving the desired load disturbance rejection performance, whereas the second approach is proposed to achieve the desired setpoint performance. In both the approaches, matching between the desired model and the closed-loop system with the controller is done at a low-frequency point. Model matching at low-frequency points yields a linear algebraic equation and the solution to these equations yields the controller parameters.
Findings
Simulations have been conducted on several examples covering high order stable, integrating, double integrating processes with time delay and nonlinear continuous stirred tank reactor. The performance of the proposed scheme has been compared with recently reported work having modified cascade control configurations, sliding mode control, model predictive control and fractional order control. The performance of both the proposed schemes is either better or comparable with the recently reported methods. However, the proposed method based on desired load disturbance rejection performance outperforms among all these schemes.
Originality/value
The main advantages of the proposed approaches are that they are directly applicable to any order processes, as they are free from time delay approximation and plant order reduction. In addition to this, the proposed schemes are capable of handling a wide range of different dynamical processes in a unified way.