This paper aims to investigate the evolution law of surface characteristic of corroded cold-formed thin-walled steel in industrial environments.
Abstract
Purpose
This paper aims to investigate the evolution law of surface characteristic of corroded cold-formed thin-walled steel in industrial environments.
Design/methodology/approach
Five test specimens sourced from cold-formed thin-walled C-shaped steel that have been in service for three years in actual industrial environments were subjected to surface characteristic test. The surface characteristic of corroded hot-rolled steel and cold-formed steel were compared and analyzed. The relationship between the surface morphology parameters and the average corrosion depth was established.
Findings
The evolution law of the surface morphology of corroded cold-formed thin-walled steel and corroded hot-rolled steel was similar. The frequency histogram of corrosion depth was mainly single peak with high values on the middle and low values on both sides. The corrosion depth conformed to the normal distribution. The roughness average height and the root mean square of surface height gradually increased linearly with increasing the average corrosion depth.
Originality/value
The reduction in the standard deviation of corrosion depth, the maximum corrosion depth, the roughness average height and the root mean square of surface height of the cold-formed thin-walled steel was smaller than those of the hot-rolled steel.
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Keywords
Yanghua Jin, Biao Nie and Yuchun Xiao
To identify the typical multilevel issues in social science, as well as illustrate the theoretical basis, hierarchical models and empirical exemplars of multilevel paradigm.
Abstract
Purpose
To identify the typical multilevel issues in social science, as well as illustrate the theoretical basis, hierarchical models and empirical exemplars of multilevel paradigm.
Design/methodology/approach
Hierarchical and multilevel data are extremely common in social systems, but multilevel analysis is constrained by statistical techniques. With the development of social system theory and empirical methods such as hierarchical structure modeling and latent growth modeling, multilevel paradigm can be used to analyze multilevel data. So it is necessary to identify typical multilevel phenomena in social science and discuss multilevel modeling techniques.
Findings
This paper identifies four typical multilevel phenomena in social system study: hierarchical and clustered sampling, collective construct research, longitudinal repeated measures, and event history analysis. Hierarchical structure modeling and latent growth modeling are effective multilevel analysis techniques in social science because of their advantages in the integration of social system research.
Research limitations/implications
The quality and availability of multilevel data are the main limitations regarding which model will be applied.
Practical implications
The paper can aid the provision of effective multilevel models to social workers.
Originality/value
This paper provides information on application of multilevel modeling in social science.
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Biao Yang, Ying Yang and Sharon Williams
The paper aims to explore the application of manufacturing postponement in a service setting.
Abstract
Purpose
The paper aims to explore the application of manufacturing postponement in a service setting.
Design/methodology/approach
In elaborating on the many key differences between goods and services highlighted in the literature, it has been argued that postponement strategies developed in manufacturing have a potential for improving service performance. The authors then examine the implications of postponement for the service push‐pull boundary and the line of visibility.
Findings
A focus on postponement at the service push‐pull boundary enables more activities to be performed in advance. Its benefits include reducing costs and shortening service delivery time. Postponement can also assist service providers in re‐locating the line of visibility to develop a more effective service operation.
Originality/value
While the significant economic benefits of postponement have been documented in manufacturing companies, the literature has also mentioned the potential role of postponement in service. However, very little has been written with respect to the exploitation of the transferability and applicability of postponement to a service setting. In this paper, the authors have explored what value postponement might have to offer for service operations. The application of postponement has a potential for service performance akin to what is expected of a manufacturing organisation.
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Yiting Kang, Biao Xue, Jianshu Wei, Riya Zeng, Mengbo Yan and Fei Li
The accurate prediction of driving torque demand is essential for the development of motion controllers for mobile robots on complex terrains. This paper aims to propose a hybrid…
Abstract
Purpose
The accurate prediction of driving torque demand is essential for the development of motion controllers for mobile robots on complex terrains. This paper aims to propose a hybrid model of torque prediction, adaptive EC-GPR, for mobile robots to address the problem of estimating the required driving torque with unknown terrain disturbances.
Design/methodology/approach
An error compensation (EC) framework is used, and the preliminary prediction driving torque value is achieved using Gaussian process regression (GPR). The error is predicted using a continuous hidden Markov model to generate compensation for the prediction residual caused by terrain disturbances and uncertainties. As the final step, a gain coefficient is used to adaptively tune the significance of the compensation term through parameter resetting. The proposed model is verified on a sample set, including the driving torque of a mobile robot on three different sandy terrains with two driving modes.
Findings
The results show that the adaptive EC-GPR yields the highest prediction accuracy when compared with existing methods.
Originality/value
It is demonstrated that the proposed model can predict the driving torque accurately for mobile robots in an unconstructed environment without terrain identification.
Details
Keywords
Himanshu Kumar, Gurjeet Singh, Ankit Yadav and Müslüm Arici
This study aims to address the low thermal conductivity and suboptimal performance of phase change materials (PCMs) by examining the impact of geometric adjustments on their…
Abstract
Purpose
This study aims to address the low thermal conductivity and suboptimal performance of phase change materials (PCMs) by examining the impact of geometric adjustments on their melting rate.
Design/methodology/approach
A two-dimensional numerical model was created to investigate the effect of different positions and angular inclinations of the inside heating surface (IHS) on the melting rate of PCM within a latent heat thermal energy storage system. The model analysed the IHS at the centre and below the centre at various positions (10, 20, 30 and 40 mm) and inclinations (0°, 15°, 30°, 45°, 60°, 75° and 90°).
Findings
The 90° inclination (vertical) significantly reduced the melting time by 75% compared to the 0° inclination (horizontal). The best melting performance was recorded with the IHS positioned 20 mm below the centre. At a 30° inclination, the maximum reduction in melting time was observed with the IHS at 30 and 40 mm placements. The system demonstrated the highest energy storage capacity of 307.72 kJ/kg at a 75° inclination with the IHS positioned 10 mm laterally, and the lowest capacity of 255.02 kJ/kg at a 0° inclination with the IHS at a 30 mm lateral position.
Practical implications
To address the deficient part of PCM like low thermal conductivity and below level performance characteristics, a structural (geometrical) adjustment was developed to study the effect on the melting rate of PCM without any cost addition. Using the computational model, an optimised thermal energy storage system is developed that can play a pivotal role in improving the applicability of thermal energy storage systems.
Originality/value
This research is novel in simultaneously investigating the numerical characteristics of PCM melting behaviour with different lateral positions and angular orientations of the IHS. A unique design modification was introduced, using a 2D numerical model and simulations to explore the effects under isothermal conditions.