Abstract
Purpose
The purpose of this study is to focus on numerical simulation investigations of deformation analysis of asymmetric break-down rolling of a hollow steel, which seriously affects the service life of the final product.
Design/methodology/approach
The 3D rigid-plastic thermo-mechanical coupled finite element method (FEM) for a large strain was used to analyze metal deformation in the deformation zone for asymmetric rolling with different roller diameters.
Findings
The distribution of stress, strain and dimension accuracy for different diameters was obtained. The results show that the additional shear strain which is different from the normal compression deformation is generated in an asymmetric rolling process. The higher the ratio between upper and lower diameters, the greater the additional shear deformation.
Originality/value
Asymmetric rolling is an important factor affecting the dimensional accuracy of the hollow steel. This study can provide a theoretical basis for developing a reasonable rolling process of the hollow steel.
Pravin Suryawanshi and Pankaj Dutta
The emergence of risk in today's business environment is affecting every managerial decision, majorly due to globalization, disruptions, poor infrastructure, forecasting errors…
Abstract
Purpose
The emergence of risk in today's business environment is affecting every managerial decision, majorly due to globalization, disruptions, poor infrastructure, forecasting errors and different uncertainties. The impact of such disruptive events is significantly high for perishable items due to their susceptibility toward economic loss. This paper aims to design and address an operational planning problem of a perishable food supply chain (SC).
Design/methodology/approach
The proposed model considers the simultaneous effect of disruption, random demand and deterioration of food items on business objectives under constrained conditions. The study describes this situation using a mixed-integer nonlinear program with a piecewise approximation algorithm. The proposed algorithm is easy to implement and competitive to handle stationary as well as nonstationary random variables in place of scenario techniques. The mathematical model includes a real-life case study from a kiwi fruit distribution industry.
Findings
The study quantifies the performance of SC in terms of SC cost and fill rate. Additionally, it investigates the effects of disruption due to suppliers, transport losses, product perishability and demand stochasticity. The model incorporates an incentive-based strategy to provide cost-cutting in the existing business plan considering the effect of deterioration. The study performs sensitivity analysis to show various “what-if” situations and derives implications for managerial insights.
Originality/value
The study contributes to the scant literature of quantitative modeling of food SC. The research work is original as it integrates a stochastic (uncertain) nature of SC simultaneously coupled with the effect of disruption, transport losses and product perishability. It incorporates proactive planning strategies to minimize the disruption impact and the concept of incremental quantity discounts on lot sizes at a destination node.
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Kanhua Yu, Jian Gong, Yan Jing, Shuqian Liu and Shihao Liang
Many cities of various types are distributed in the large area of mountainous regions in China. In these cities, there are acute contradictions between man and earth. Considering…
Abstract
Many cities of various types are distributed in the large area of mountainous regions in China. In these cities, there are acute contradictions between man and earth. Considering that the space growth mode of mountainous cities is widely different from that of flatland cities, the fractal method was adopted in the research aimed at demarcating the urban growth boundary of mountainous cities. The fractal features of the investigated mountainous cities in space were figured out via inference from their function, dimension, region, grade, and environment, and the fractal mode and conceptual framework of urban growth boundary of Qin-Ba mountainous region were constructed according to some concepts and methods such as fractal dimension, fractal network, and fractal order. In the research, the traditional urban growth boundary form-was decomposed into scattered points (point form), paths (linear form), and patches (plane form) to form the fractal theory units for the research of urban growth boundary, and the leading idea, procedure, and control method for “fractal demarcation of urban growth boundary” were established to provide strategies for demarcation of urban space growth boundary of Qin-Ba mountainous region.
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Yuexin Zhang, Lihui Wang and Yaodong Liu
To reduce the effect of parameter uncertainties and input saturation on path tracking control for autonomous combine harvester, a path tracking controller is proposed, which…
Abstract
Purpose
To reduce the effect of parameter uncertainties and input saturation on path tracking control for autonomous combine harvester, a path tracking controller is proposed, which integrates an adaptive neural network estimator and a saturation-aided system.
Design/methodology/approach
First, to analyze and compensate the influence of external factors, the vehicle model is established combining a dynamic model and a kinematic model. Meanwhile, to make the model simple, a comprehensive error is used, weighting heading error and position error simultaneously. Second, an adaptive neural network estimator is presented to calculate uncertain parameters which eventually improve the dynamic model. Then, the path tracking controller based on the improved dynamic model is designed by using the backstepping method, and its stability is proved by the Lyapunov theorem. Third, to mitigate round-trip operation of the actuator due to input saturation, a saturation-aided variable is presented during the control design process.
Findings
To verify the tracking accuracy and environmental adaptability of the proposed controller, numerical simulations are carried out under three different cases, and field experiments are performed in harvesting wheat and paddy. The experimental results demonstrate the tracking errors of the proposed controller that are reduced by more than 28% with contrast to the conventional controllers.
Originality/value
An adaptive neural network-based path tracking control is proposed, which considers both parameter uncertainties and input saturation. As far as we know, this is the first time a path tracking controller is specifically designed for the combine harvester with full consideration of working characteristics.
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Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American…
Abstract
Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American preemptive invasion and occupation of Afghanistan and Iraq and the subsequent prisoner abuse, such an existence seems to be farther and farther away from reality. The purpose of this work is to stop this dangerous trend by promoting justice, love, and peace through a change of the paradigm that is inconsistent with justice, love, and peace. The strong paradigm that created the strong nation like the U.S. and the strong man like George W. Bush have been the culprit, rather than the contributor, of the above three universal ideals. Thus, rather than justice, love, and peace, the strong paradigm resulted in in justice, hatred, and violence. In order to remove these three and related evils, what the world needs in the beginning of the third millenium is the weak paradigm. Through the acceptance of the latter paradigm, the golden mean or middle paradigm can be formulated, which is a synergy of the weak and the strong paradigm. In order to understand properly the meaning of these paradigms, however, some digression appears necessary.
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Shan Peng, Ranran Yang, Binglong Lei, Yun Gao, Renhua Chen, Xiaohong Xia and Kevin P. Homewood
This paper aims to systematically demonstrate a methodology to determine the relative and absolute encapsulation efficiencies (αRe and αAb) for thermally- and chemically-robust…
Abstract
Purpose
This paper aims to systematically demonstrate a methodology to determine the relative and absolute encapsulation efficiencies (αRe and αAb) for thermally- and chemically-robust inorganic pigments, typically like ZrSiO4-based pigments, thereby enhancing their coloring performance.
Design/methodology/approach
The authors designed a route, surplus alkali-decomposition and subsequently strong-acid dissolution (SAD2) to completely decompose three classic zircon pigments (Pr–ZrSiO4, Fe2O3@ZrSiO4 and CdS@ZrSiO4) into clear solutions and preferably used inductively coupled plasma-optical emission spectrometry (ICP-OES) to determine the concentrations of host elements and chromophores, thereby deriving the numeric data and interrelation of αRe and αAb.
Findings
Zircon pigments can be thoroughly decomposed into some dissoluble zirconate–silicate resultants by SAD2 at a ratio of the fluxing agent to pigment over 6. ICP-OES is proved more suitable than some other quantification techniques in deriving the compositional concentrations, thereby the values of αRe and αAb, and their transformation coefficient KRA, which maintains stably within 0.8–0.9 in Fe2O3@ZrSiO4 and CdS@ZrSiO4 and is slightly reduced to 0.67–0.85 in Pr–ZrSiO4.
Practical implications
The SAD2 method and encapsulation efficiencies are well applicable for both zircon pigments and the other pigmental or non-pigmental inhomogeneous systems in characterizing their accurate composition.
Originality/value
The authors herein first proposed strict definitions for the relative and absolute encapsulation efficiencies for inorganic pigments, developed a relatively stringent methodology to determine their accurate values and interrelation.
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Keywords
Sheng Zhou, Fei Liu, Xiaofeng Weng, Jiacheng Mai and Shaoxiang Feng
This research aims to investigate the trajectory tracking problem for a four-wheel independent drive autonomous vehicle (4WID) and propose an integrated, coordinated control…
Abstract
Purpose
This research aims to investigate the trajectory tracking problem for a four-wheel independent drive autonomous vehicle (4WID) and propose an integrated, coordinated control strategy to address the mutual interference between trajectory tracking and stability control in extreme cases.
Design/methodology/approach
The authors establish an adaptive preview model that modifies the preview distance based on vehicle speed. They utilize a three-degrees-of-freedom vehicle model and employ model predictive control to calculate the necessary front wheel angle for trajectory tracking. In terms of longitudinal control, a longitudinal coordinated control mechanism is established to achieve the two conflicting objectives of trajectory tracking accuracy and dynamic stability through early deceleration. A stability controller based on sliding mode control (SMC) is designed, considering tire constraints and tracking the optimal yaw angle and sideslip angle. Furthermore, a lateral coordinated control strategy is developed, considering the weight coefficient of stability control, and the yaw moment is calculated and distributed based on the vehicle torque requirements.
Findings
The proposed integrated, coordinated control strategy successfully addresses the mutual interference between trajectory tracking and stability control in extreme cases for the 4WID vehicle. The strategy achieves trajectory tracking accuracy, dynamic stability and reduced energy consumption while taking into account tire constraints.
Originality/value
We have proposed a cooperative control strategy for the trajectory tracking problem of autonomous driving vehicles. This strategy is different from previous methods in that we have taken into account the integrated dynamic control in both longitudinal and lateral directions, balancing the conflicting control requirements and reducing energy consumption, improving trajectory tracking accuracy and vehicle dynamic stability. We have verified the feasibility of this strategy through joint simulation under different driving conditions.
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W. James Jacob, Huiyuan Ye, Miranda L. Hogsett, Annette T. Han, Midori Hasegawa, Lili Jia, Lin Jiang and Shangmou Xu
In this chapter, the authors provide a historical overview of the development of comparative and international education societies throughout the earth. In most cases, these…
Abstract
In this chapter, the authors provide a historical overview of the development of comparative and international education societies throughout the earth. In most cases, these societies have gradually grown and continue to thrive; in other cases, some comparative education societies have become dormant and a few no longer exist. A historical analysis that outlines the rise and fall of comparative education societies is provided. An overview of the World Council of Comparative Education Societies is also discussed, including its lead organizational role in serving as a historical hub to help comparative education societies preserve and disseminate their respective histories. The chapter concludes with suggestions on how anyone can get involved to help contribute to the history preservation of comparative education at the individual, national, regional, and global levels.
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Khahan Na-Nan and Natthaya Wongsuwan
Perceived workplace support (PWS) is an employee’s perception of perceived organisational support (POS), perceived supervisor support (PSS), perceived co-worker support (PCS) and…
Abstract
Purpose
Perceived workplace support (PWS) is an employee’s perception of perceived organisational support (POS), perceived supervisor support (PSS), perceived co-worker support (PCS) and perceived sufficient resource support (PSRS) to operate effectively. The purpose of this paper is to explore the development and validation of employee’s PWS instrument in small and medium-sized enterprises (SMEs).
Design/methodology/approach
A total of 15 items of employees’ PWS instrument in SMEs were developed from the measurement base of earlier published research, concepts and theory. The instrument was applied to a cross-sectional study and data were collected as factor analyses to confirm and ascertain construct validity. Reliability was tested by measuring the internal consistency.
Findings
The instrument showed excellent reliability at 0.894. Four factors as “POS”, “PSS”, “PCS” and “PSRS” were extracted and confirmed from the confirmatory factor analysis.
Originality/value
PWS studies are often used by researchers, human resource departments and organisations to investigate the level of employee support. The instrument developed from this study will enable researchers, human resource departments and organisations to explore levels of POS, PSS, PCS and PSRS.
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Emmanuel Ejiofor Anike, Messaoud Saidani, Eshmaiel Ganjian, Mark Tyrer and Adegoke Omotayo Olubanwo
This paper aims to review the effect of using recycled aggregates (RA) on the properties of recycled aggregate concrete (RAC) following the steady rise in global demand for…
Abstract
Purpose
This paper aims to review the effect of using recycled aggregates (RA) on the properties of recycled aggregate concrete (RAC) following the steady rise in global demand for concrete and the large generation of construction and demolition waste.
Design/methodology/approach
This study reviewed relevant literature of research work carried out by previous researchers, leading to a deeper understanding of the properties of both RA and RAC. The properties of RA and RAC reported in the various studies were then compared to their corresponding natural aggregate (NA) and natural aggregate concrete, as well as the specifications provided in different codes of practice. In addition, the mix design methods appropriate to RAC and the cost implication of using RA were reviewed.
Findings
Findings show that the contribution of RA to strength appears inferior in comparison to NA. The shortcoming is attributed to the mortar attached to the RA, which raises its water absorption capacity and lowers its density relative to those of NA. However, it has been reported that the use of regulated quantity of RA, new mixing and proportioning methods, the addition of admixtures and strengthening materials such as steel fibres, can improve both mechanical and durability properties of RAC. Cost evaluation also showed that some savings can be realized by using RA instead of NA.
Originality/value
This research serves as a guide for future works and suggests that the use of RA as aggregate in new concrete is technically possible, depending on the mix design method adopted.