Ba-Thanh Vu, Hung Le-Quang and Qi-Chang He
The phase-field method of interfacial damage is used to simulate the damage in composite structures containing the brittle orthotropic materials and their interface.
Abstract
Purpose
The phase-field method of interfacial damage is used to simulate the damage in composite structures containing the brittle orthotropic materials and their interface.
Design/methodology/approach
In the brittle fracture modeling, the strain tensor is decomposed into positive and negative parts characterizing tension and compression behaviors. By requiring an elastic energy preserving transformation involving the elastic stiffness tensor, these two strain parts must satisfy the orthogonality condition in the sense that the elastic stiffness tensor responds as a metric. However, most of the recent phase-field methods for brittle fracture do not verify this orthogonality condition. Additionally, to describe the damage in structures with anisotropic phases, recent studies have used multiple phase-field variables, with each preferential orientation represented by a phase-field variable to describe the bulk damage of component materials. This approach increases the complexity of simulation procedure. These disadvantages motivate the present study aimed at enhancing the simulation method.
Findings
The present study improves the phase-field method of interfacial damage by (1) incorporating the strain orthogonality condition into the phase-field method; (2) using only one phase-field variable instead of multiple phase-field variables to simulate damage in component orthotropic phases; and (3) investigating the interaction between interfacial damage and bulk damage as well as the effect of orientation tensor of preferential orientation in each orthotropic phase and the interfacial parameters on crack branching in composite structures.
Originality/value
Through several simulation examples, the present simulation method is proven to be accurate, effective, and helps the simulation process simpler than previous relevant methods.
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Wen He, Chongyi Chang, Lan Li and Yupan Song
The study aims to build a high-precision longitudinal dynamics model for heavy-haul trains and validate it with line test data, present an optimization method for multi-stage…
Abstract
Purpose
The study aims to build a high-precision longitudinal dynamics model for heavy-haul trains and validate it with line test data, present an optimization method for multi-stage cyclic brakes based on the model and conduct a multi-objective detailed evaluation of the driver’s manipulation during cyclic braking.
Design/methodology/approach
The high-precision longitudinal train dynamics model was established and verified by the cyclic braking test data of the 20,000 t heavy-haul combination train on the long and steep downgrade. Then the genetic algorithm is employed for optimization subsequent to decoupling multiple cyclic braking procedures, with due consideration of driver operation rules. For evaluation, key manipulation assessments in the scenario are prioritized, supplemented by multi-objective evaluation requirements, and the computational model is employed for detailed evaluation analysis.
Findings
Based on the model, experimental data reveal that the probability of longitudinal force error being less than 64.6 kN is approximately 68%, 95% for less than 129.2 kN and 99.7% for less than 193.8 kN. Upon optimizing manipulations during the cyclic braking, the maximum reduction in coupler force spans from 21% ∼ 23.9%. And the evaluation scores imply that a proper elevation of the releasing speed favors safety. A high electric braking force, although beneficial to some extent for energy-saving, is detrimental to reducing coupler force.
Originality/value
The results will provide a theoretical basis and practical guidance for further ensuring the safety and energy-efficient operation of heavy haul trains on long downhill sections and improving the operational quality of heavy-haul trains.
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The purpose of this paper is to examine users’ decision-making mechanism of speculative investment behavior and its sequential consequences in the Bitcoin context from a…
Abstract
Purpose
The purpose of this paper is to examine users’ decision-making mechanism of speculative investment behavior and its sequential consequences in the Bitcoin context from a dual-systems perspective.
Design/methodology/approach
Original data were collected via a survey of 334 participants with experience in Bitcoin speculative investment. The partial least squares method was used to test the proposed model.
Findings
Speculative investment behavior in the Bitcoin context is driven by strong impulse and weak self-control, leading to negative consequences. The extent of the imbalance between the two cognitive systems is greater with the subjective norm than without it, thus facilitating speculative investment behavior. Noteworthy differences in the impulse and self-control effects on Bitcoin speculative investment are found with differences in Bitcoin objective and subjective knowledge.
Originality/value
This study is the first attempt to empirically investigate users’ decision-making mechanism used when speculating in Bitcoin.
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Chang He, Fu Jia, Liukai Wang, Lujie Chen and Kieran Fernandes
Corporate social responsibility (CSR) decoupling indicates a misalignment between how firms report CSR and what firms actually practice with respect to CSR. The purpose of this…
Abstract
Purpose
Corporate social responsibility (CSR) decoupling indicates a misalignment between how firms report CSR and what firms actually practice with respect to CSR. The purpose of this paper is to examine the relationship between CSR decoupling and financial performance and the factors affecting this relationship.
Design/methodology/approach
This paper collects and combines secondary panel data from multiple sources of Chinese listed firms from 2008 to 2020 to test the direct impact of CSR decoupling on firms’ financial performance and the moderating role of customer structure and operational slack.
Findings
This paper finds that CSR decoupling is negatively associated with firms’ financial performance. These findings further suggest that the negative relationship can be suppressed by customer stability and operational slack, but amplified by customer concentration. These conclusions remain robust to alternate measures of independent and dependent variables and narrower samples.
Originality/value
In the literature, the effect of CSR on firms’ financial performance is inconclusive. This is the first study to examine the impact of CSR decoupling on firms’ financial performance and the factors affecting this relationship. This paper contributes to the CSR decoupling literature from an operations and supply chain management perspective.
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The existence and continued growth of the invisible web creates a major challenge for search engines that are attempting to organize all of the material on the web into a form…
Abstract
Purpose
The existence and continued growth of the invisible web creates a major challenge for search engines that are attempting to organize all of the material on the web into a form that is easily retrieved by all users. The purpose of this paper is to identify the challenges and problems underlying existing work in this area.
Design/methodology/approach
A discussion based on a short survey of prior work, including automated discovery of invisible web site search interfaces, automated classification of invisible web sites, label assignment and form filling, information extraction from the resulting pages, learning the query language of the search interface, building content summary for an invisible web site, selecting proper databases, integrating invisible web‐search interfaces, and accessing the performance of an invisible web site.
Findings
Existing technologies and tools for indexing the invisible web follow one of two strategies: indexing the web site interface or examining a portion of the contents of an invisible web site and indexing the results.
Originality/value
The paper is of value to those involved with information management.
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Wei Feng, Yuqin Wu and Yexian Fan
The purpose of this paper is to solve the shortage of the existing methods for the prediction of network security situations (NSS). Because the conventional methods for the…
Abstract
Purpose
The purpose of this paper is to solve the shortage of the existing methods for the prediction of network security situations (NSS). Because the conventional methods for the prediction of NSS, such as support vector machine, particle swarm optimization, etc., lack accuracy, robustness and efficiency, in this study, the authors propose a new method for the prediction of NSS based on recurrent neural network (RNN) with gated recurrent unit.
Design/methodology/approach
This method extracts internal and external information features from the original time-series network data for the first time. Then, the extracted features are applied to the deep RNN model for training and validation. After iteration and optimization, the accuracy of predictions of NSS will be obtained by the well-trained model, and the model is robust for the unstable network data.
Findings
Experiments on bench marked data set show that the proposed method obtains more accurate and robust prediction results than conventional models. Although the deep RNN models need more time consumption for training, they guarantee the accuracy and robustness of prediction in return for validation.
Originality/value
In the prediction of NSS time-series data, the proposed internal and external information features are well described the original data, and the employment of deep RNN model will outperform the state-of-the-arts models.
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Victor Chang, Yian Chen and Chang Xiong
The purpose of this paper is to gain a deeper insight on how education boosts economic progress in key emerging economies. This project is aimed at exploring the interactive…
Abstract
Purpose
The purpose of this paper is to gain a deeper insight on how education boosts economic progress in key emerging economies. This project is aimed at exploring the interactive dynamics between the tertiary education sector and economic development in BRICS countries. The author also aims to examine how the structure of higher education contributes to economic expansion.
Design/methodology/approach
The author uses the time series data of BRICS countries across approximately two decades to determine the statistical causality between the size of tertiary enrollment and economic development. The linear regression model is then used to figure out the different impact levels of academic and vocational training programs at the tertiary level to economic development.
Findings
Data from all BRICS countries exhibited a unidirectional statistical causality relationship, except the Brazilian data. The national economic expansion Granger Caused increased tertiary enrollment in Russia and India, while in China and South Africa, higher education enrollment Granger Caused economic progress. The impact from tertiary academic training is found to be positive for all BRICS nations, while tertiary vocation training is shown to have impaired the Russian and South African economy.
Research limitations/implications
This project is based on a rather small sample size, and the stationary feature of the time series could be different should a larger pool of data spanning a longer period of time is used. In addition, the author also neglects other control variables in the regression model. Therefore, the impact level could be distorted due to possible omitted variable bias.
Practical implications
Tertiary academic study is found to have a larger impact level to all countries’ economic advancement, except for China, during the time frame studied. There is a statistical correlation between the education and economic progress. This is particularly true for BRICS countries, especially China. But the exception is Brazil.
Social implications
The government should provide education up to the certain level, as there is a direct correlation to the job creation and economic progress. Furthermore, the government should also work closely with industry to ensure growth of industry and creation of new jobs.
Originality/value
The comparative analysis and evaluation of the dynamic interaction of tertiary enrollment and economic output across all five BRICS nations is unique, and it deepens the understanding of the socioeconomic development in these countries from a holistic management perspective.
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Waheed Ali Umrani, Rukhman Solangi, Mumtaz Ali Memon, Asmaa Hadeesa and Soonhan Khoso
Learning outcomes are as follows: Understand performance appraisal process and tools; apply theory X and Theory Y in managing resistance to performance evaluation; identify the…
Abstract
Learning outcomes
Learning outcomes are as follows: Understand performance appraisal process and tools; apply theory X and Theory Y in managing resistance to performance evaluation; identify the causes and symptoms of resistance; identify and apply managing resistance approaches.
Case overview/synopsis
After attaining the height of success in terms of imparting quality education and contributing to the creation of many learned persons of the society, Public school Sukkur was facing the downward trending success for many reasons. After the takeover of management control by Sukkur IBA University, the school was upward trending for quality education, state of the art infrastructure, advanced educational lab, modern teaching methodologies. With such a change, resistance was a must. Both Active and Passive resistance from the stakeholders was impeding the success of newly named IBA-Public School Sukkur. Particularly, the resistance against the implementation of the Performance Appraisal tool and its administration. With the resistance from employees, Chang, Principal IBA Public School Sukkur had to come up a solution for the smooth administration and implementation of Performance Appraisal and manage the resistance from the employees and ensure the continuous improvement through performance appraisal.
Complexity academic level
Case study is applicable for the MBA students.
Supplementary materials
Teaching Notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.
Subject code
CSS 7: Management Science.
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He Zhang, Shaowei Yang and Zhengfeng Ma
Existing three-dimensional (3D) road-surface models use approximation methods such as a set of discrete triangular patches and cannot accurately describe changes in the…
Abstract
Purpose
Existing three-dimensional (3D) road-surface models use approximation methods such as a set of discrete triangular patches and cannot accurately describe changes in the geometrically designed elements along the road. This paper aims to construct a 3D road-surface model with combinations of geometric design invariants and apply the proposed model to analyse the state of motion of a wheel’s centre.
Design/methodology/approach
In this paper, the 3D road surface is modelled as a continuous function with combinations of geometric design invariants. By introducing the theories of differential geometries and rigid body dynamics, a wheel-road model wherein a wheel fixed to a Darboux frame moves along a curved road surface is constructed, and the wheel time-dependent properties of the velocity, angular velocity and acceleration at an arbitrary point of the surface are described using road geometry design invariants.
Findings
This paper adopts the Darboux frame to study the instantaneous spin-rolling motion of a wheel. It is found that the magnitudes of the spin-rolling velocity, the acceleration and the geometric invariants of the road surface, including the geodesic curvature, the normal curvature and the geodesic torsion, determine the instantaneous states of motion of a wheel.
Originality/value
This work provides a theoretical foundation for future studies of wheel motion states, such as the relationship between road geometry design invariants and driving safety, vehicle lane changing and other vehicle microbehaviours. New insights are gained in the areas of road safety and vehicles incorporating artificial intelligence.
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This scholarly work aims to investigate the business career of Alfred J. Kohlberg, an American importer of hand-embroidered handkerchiefs in 1922-1957.
Abstract
Purpose
This scholarly work aims to investigate the business career of Alfred J. Kohlberg, an American importer of hand-embroidered handkerchiefs in 1922-1957.
Design/methodology/approach
This paper uses archival resources from the National Archives, the Herbert Hoover Presidential Library, the Hoover Institution Archives, the Federal Bureau of Investigation, Custom Courts records, Japanese Government records and other government documents.
Findings
Scholars have focused on how Kohlberg’s political activities paved the way for McCarthyism. The sources of his vast wealth have not received attention. Kohlberg parlayed a 1922 trip to Asia into a highly lucrative importing business specializing in Chinese napery. By 1930, he mostly imported hand-embroidered handkerchiefs for sale in upscale American department stores. He employed as many 12,000 people in his Shantou godown and contracted for the employment of at least 100,000 embroiderers and perhaps many hundreds of thousands more. Despite American Government policy and the wishes of other importers, Japanese occupation authority documents show that Kohlberg negotiated a bribe to keep the port open. This paper concludes that Kohlberg’s business reflected traditional Chinese business organization. While he stressed his patriotic activities during the Second World War, Kohlberg promoted his business interest over the national interest. Finally, the Chaoshan Region prospered by providing the modern world with traditional hand-produced goods.
Research limitations/implications
This work explains how the Chaoshan Region functioned in the global economy. It calls for a deeper examination of this entire industry in China and around the world.
Originality/value
This work uses documents from multiple archives, including Japan and the USA. It also includes declassified documents from the Federal Bureau Investigation. This work constitutes a template for international business history.