Search results

The interaction between rock mass structural planes and dynamic stress levels is important to determine the stability of rock mass structures in underground geotechnical engineering. In this work, the authors aim to focus on the degradation effects of fracture geometric parameters and unloading stress paths on rock mechanical properties.

A three-dimensional Particle Flow Code (PFC3D) was used for a systematic numerical simulation of the strength failure and cracking behavior of granite specimens containing prefabricated cracks under conventional triaxial compression and triaxial unilateral unloading. The authors demonstrated the unique mechanical response of prefabricated fractured rock under two conditions. The crack initiation, propagation, and coalescence process of pre-fissured specimens were analyzed in detail.

The authors show that the prefabricated cracks and unilateral unloading conditions not only deteriorate the mechanical strength but also have significant differences in failure modes. The degrading effect of cracks on model strength increases linearly with the decrease of the dip angle. Under the condition of true triaxial unilateral unloading, the deterioration effect of peak strength of rock is very significant, and unloading plays a role in promoting the instability failure of rock after peak, making the rock earlier instability failure. Associating with the particle vector diagram and crack coalescence process, the authors find that model failure mode under unilateral loading conditions is obviously distinct from that in triaxial loading. The peak strain in the unloading direction increases sharply, resulting in a new shear slip.

This study is expected to improve the understanding of the strength failure and cracking behavior of fractured rock under unilateral unloading.

This paper aims to explore the relationship between environmental regulation, technological innovation and manufacturing quality competitiveness to provide some references for emission reduction activities and improvements in manufacturing quality competitiveness to achieve environmental protection targets and economic development as part of a win–win situation.

Based on the structure-behavior-performance paradigm and Grabowski’s research, a new empirical model was provided. The software, EViews 6.0, was used for econometric analysis. Regression analysis was adopted to explore the three indicators’ relationships.

First, environmental regulation can promote technological innovation effectively. Second, compared with wasted gas and wasted solids, investment in wasted water control promotes Chinese technological innovation most. Third, the impact of research and development investment, induced by environmental regulation, on manufacturing quality competitiveness is greater than that induced by non-environmental regulation. Fourth, the impact of lagged two-phase environmental regulation on manufacturing quality competitiveness is similar to that of lagged one-phase regulation.

The issue that Chinese manufacturing is facing is how to manage the trade-off between pollution control investment and improved quality competitiveness. This study enables managers to understand how to better implement environmental regulation initiatives while achieving environmental protection and quality competitiveness as part of a win–win situation.

This paper analyzes the relationships between environmental regulation, technological innovation and manufacturing quality competitiveness for the first time and provides the basic argument for integrating Chinese environmental regulation with quality competitiveness to reveal the uniqueness of the circumstances determining China’s economic development.

This paper aims to make a systematic study on the factors that hinder the development of China’s intelligent automobile manufacturing industry; based on comprehensive understanding of these obstacles and by optimization means, ultimately, the healthy and sustainable development of intelligent automobile manufacturing industry in China can be promoted.

Based on a questionnaire survey of intelligent automobile manufacturing listed companies in China, first, fuzzy semantic scale was adopted to collect respondents’ choices, the fuzzy score function is used to calculate the fuzzy score value and these data are used as the basis for subsequent model analysis. Then, structural equation modeling (SEM) was adopted to analyze the causal relationship between influencing factors to explore the main hinder factors.

It is found that, in the short term, the backwardness of technological industrialization is the main reason leading to low permeability of intelligent automobile; in the medium term, the imperfect industrial R&D ability and the insufficiency of infrastructure are major causes for high manufacturing cost and low competitiveness of intelligent automobile manufacturing industry; in the long term, the lack of national policy and industrial strategic planning is the main factors affect intelligent automobile manufacturing cost and the industry competitiveness.

The research conclusion has important policy implications for promoting intelligent automobile manufacturing sustainable development. In recent years, China’s intelligent automobile manufacturing industry has gradually stepped out of breeding period; therefore, the role of government should be gradually transformed from participants to managers and regulators. Considering the fact that intelligent automobile cost is very high, and still higher than the cost of fuel vehicle, government should focus on the issues such as improving R&D capabilities, infrastructure construction, policy framework system, legal system and technological industrialization. Specifically, in short-term planning, improving technological industrialization level is the key to development; in medium-term planning, policymakers should focus on the improvement of R&D capabilities and infrastructure; considering the long-term development, establishing appropriate national policies and dealing with the adverse impact of imperfect strategic planning are the most sensible choice.

This paper analyzes the factors that hinder the development of China’s intelligent automobile manufacturing industry for the first time, and provides the basic logic of integration factors at different levels with the development of intelligent automobile to reveal the uniqueness and facts of China’s economic development.

This study aims to investigate the efficacy of micro dimple in inhibiting stick-slip phenomenon on the sliding guideway.

In this study, micro-dimples were fabricated by laser on surfaces of steel disk and guideway. The disks and guideways were respectively performed pin-on-disk tribological tests and working condition experiments to study differences in lubrication condition and friction stability between textured and untextured surfaces.

Micro-dimples help reduce critical sliding speed that allows contact surfaces to enter in hydrodynamic lubrication regime. This increases hydrodynamic lubrication range and narrows speed range where stick-slip phenomenon can occur, enhancing sliding guideway’s adaptability for broader working conditions. Furthermore, friction stability on the textured surface improved, lowering the occurrence possibility of stick-slip phenomenon. Finally, difference between static and kinetic frictions on the textured surface is lower relative to the untextured surface, which decreases the critical velocity when the stick-slip phenomenon occurs.

The results indicate that laser-textured micro-dimples are significantly conducive to inhibit stick-slip phenomenon, thus providing smoother movement for the guideway and eventually increasing precision of the machine.

The purpose of this paper is to study friction and wear properties of three types of steels against paper-based friction disc, including 65Mn, 20#steel and 30CrAl, so as to obtain the appropriate working conditions for different friction materials in the transmission system.

Based on actual working conditions, pin-on-disc tests are conducted on a universal material tester. The two evaluation indexes, including average friction coefficient and variation coefficient, are introduced to analyze the different friction properties among three types of steel. Furthermore, the temperature-dependent wear pattern and wear depth are subsequently studied.

The results show that 65Mn is more suitable for working under heavy load and low velocity, but 30CrAl and 20#steel are suitable for working under light load and high velocity. Moreover, wear primarily occurs on paper-based material and peaks at about 325.

This research of different materials and friction property for friction pairs is helpful to improve the performance and prolong the service life of transmission systems.

Suitable working conditions of different friction materials are obtained, and the correlation between wear and decomposition in high temperature is verified.

Digital technology is crucial to improving a firm’s core competitiveness. However, the existing research on the relationship therein shows heterogeneity. Using digital technology can enhance competitive advantage, which is crucial for enterprises and scholars. Thus, based on the digital technology affordance theory, this study explores the relationship between digital technology affordance and digital competitive advantage.

Survey data were collected from 509 large and medium-sized manufacturing enterprises in China, and multiple regression and structural equation modelling were used to test the hypotheses. Specifically, we discuss the mediating role of digital business capability and the moderating role of organisational legitimacy.

Editability, association and visibility positively affect digital competitive advantage, and their coordination is strong. Further, they can help enterprises gain a competitive advantage through the mediating role of digital business capability (digital strategy, digital integration and regulation). However, the influence effect and action path differ per in different dimensions. Organisational legitimacy positively moderates the mediating effect of digital integration and regulation, and there is a moderated mediating effect. However, the moderating effect on the mediating effect of digital strategy is not significant.

Existing studies neglect the relationship between the coordination of digital technology functions and digital competitive advantage. This study provides a new theoretical explanation for an in-depth understanding of these issues. These findings promote the development of innovation theory and provide valuable insights for guiding the application of digital technology in enterprises.

Over the past decade, research into sharing economy platforms has gained prominence. The purpose of this study is to investigate the role of perceived value (both hedonic and utilitarian) in attracting consumer engagement in the sharing economy, as well as its link with trust.

This study used a survey method to empirically tested the proposed model using the partial least squares approach to structural equation modeling on data from 320 DiDi app users.

The study's findings revealed that both hedonic and utilitarian value had a significant effect on satisfaction and trust in the platform. Although the results showed no effect of hedonic and utilitarian values on trust in driver, the authors found trust in driver and platform, and satisfaction had significant influences on users’ continued intention to use the Taxi-hailing app. Interestingly, this study suggests that trust in the platform is transferred to trust in the driver.

The results from the Necessary Condition Analysis shows that satisfaction and utilitarian value are necessary conditions of continuance intention.

This paper discusses the urban management challenges in the Greater Kuala Lumpur area. Before examining Greater Kuala Lumpur's economic and social environment, we will look at the factors that make it a competitive and fiscally sound entity. When considering urban development and redevelopment, we consider how proposed and ongoing projects, as well as plans, hierarchical links, and road networks, contributed to the increase. Because there is no urban growth boundary, land use change and rural encroachment, as well as environmental degradation and the impact of national economic projects on urban expansion, are both rapid and linear in the analysis. This paper also considers how to manage linear development that results in the creation of new suburbs. Finally, we propose strategies for achieving sustainable urban expansion and management by balancing the financial and governance capacities of Greater Kuala Lumpur local governments.

The purpose of this paper is to focus on the machine design and control strategy of the permanent magnet synchronous generator (PMSG) system, especially utilized in variable speed applications, in order to stabilize the output voltage on the dc link over a wide speed range.

Different ac/dc power converter topologies are comparatively studied, each with an accordingly designed PMSG, so as to investigate the influence of the armature winding inductance as well as the relationship between the PMSG and power converter topologies.

Pulse width modulation (PWM) rectifier is preferable for the said application due to its good performance and controllability. Moreover, by employing the PWM rectifier, relatively large inductance of the PMSG is considered for both short-circuit current reduction and field regulation.

Field-regulating control is realized with a space vector PWM (SVPWM) rectifier, which can weaken the PMSG magnetic field during high-speed operation, while even properly enhance the field at low speed, ensuring a small change of the PMSG output voltage and a stable dc voltage.