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The purpose of this paper is to investigate the tribological performance of Cr₃C₂–NiCr–Mo–BaF₂ composite sliding against a Si₃N₄ ball at high temperatures.

A Cr₃C₂–NiCr composite and a Cr₃C₂–NiCr–Mo–BaF₂ composite were prepared using spark plasma sintering. Tribological properties of the composites were investigated using a ball-on-disk type tribotester. The relationships among the microstructure, wear mechanism and tribological performance were determined by analyzing the wear track morphologies and the glaze layer’s phase composition.

The wear rate of the Cr₃C₂–NiCr–Mo–BaF₂ composite was approximately one order of magnitude lower than that of the Cr₃C₂–NiCr composite from 700°C to 900°C when sliding against a Si₃N₄ ball. The favorable tribological performance of the Cr₃C₂–NiCr–Mo–BaF₂ composite at high temperatures results from the synergistic lubrication of MoOx, BaF₂ and BaMoO₄.

This paper reports a new Cr₃C₂–NiCr matrix self-lubricating composite with better tribological properties than Cr₃C₂–NiCr composite at temperatures up to 900°C through Mo and BaF₂ addition.

The purpose of the paper is to develop a methodological framework for supply chain risk management using the hierarchical holographic modeling approach. It analyses supply chain risks in a systematic manner and develops a hierarchical methodology for identifying, prioritizing and managing the potential supply chain risks.

This research reviews supply chain risk management literature and develops a conceptual framework, which outlines general principles and guidelines for managing risks in a systematic manner. Through decomposition, the complexity of supply chain risk can be identified by analyzing smaller subsystems.

The paper provides a conceptual framework to identify supply chain risks from multiple overlapping perspectives. The structured filtering and ranking procedure enables decision-makers to focus on the most critical risks. The research shows that the supply chain risks associated with the sub-systems within the hierarchical structure contribute to and ultimately determine the risks of the overall supply chain system.

The risks associated with each sub system within the hierarchical structure can contribute to and determine the risks of the overall supply chain system. Further applications in various companies and industry sectors would benefit supply chain managers on a case-by-case basis.

The hierarchical risk identification framework can serve as guidance for applications to specific supply chain systems and processes. The framework from a holistic overlapping perspective can efficiently and effectively help supply chain managers identify supply chain risks and facilitate the evaluation of the subsystem risks.

The paper applies system thinking in supply chain management and presents an efficient and practical framework for supply chain risk identification and evaluation.

B2B e‐hubs have been studied by IS researchers for close to a decade, and supply chain integration is a critical topic for supply chain management. However, the interface of the two topic areas has not received adequate attention from both researchers and practitioners. This paper aims to examine the impact of B2B e‐hubs on supply chain integration, with particular emphasis on information integration, B2B e‐hub architecture, and enabling technologies.

General system theory (GST) provides the theoretical framework. The main approach is theoretical analysis of information integration and development of e‐hub architecture. The paper discusses how information integration can be achieved through B2B e‐hubs and explores extensible markup language e‐hub architecture and technologies.

GST could provide the theoretical framework of integration, whereas information integration is the foundation of broader supply chain integration. E‐hubs open up communication and enlarge networking opportunities and thus tremendously affect information integration. By analyzing B2B e‐hubs, this paper explores the mechanism of information integration and points out managerial and technical limitations. Although there are many challenges, e‐hubs create value by aggregating and matching buyers and sellers, creating marketplace liquidity, and reducing transaction costs. E‐hubs could be a crucial solution to supply chain integration.

The paper uses GST as the theoretical foundation to analyze information integration in supply chain operations. The paper explores how e‐hubs can support supply chain integration, examines the design and development of B2B e‐hub architecture, and compares some enabling technologies. The research provides an understanding of how data interchange solutions can be implemented in supply chain operations.

Waiting lines and delays have become commonplace in service operations. As a result, customer waiting time guarantee is a widely used competition strategy in service industries. To implement waiting time guarantee strategy, managers need to not only know the average of waiting time, but also the variance around average waiting time. This paper aims to discuss these issues.

This research provides a mathematically exact expression for the coefficient of variation of waiting time for Markov queues. It then applies the concept of isomorphism to approximate the variance of customer waiting time in a general queue. Simulation experiments are conducted to verify the accurate approximations.

A significant feature of the approximation method is that it is mathematically tractable and can be implemented in a spreadsheet format. It provides a practical way to estimate the variance of customer waiting time in practice. The results demonstrate the usefulness of the queuing models in providing guidance on implementing appointment scheduling and waiting time guarantee strategy. Also, the spreadsheet can be used to conduct what-if analysis by inputting different parameters.

This paper develops a simple, easy-to-use spreadsheet model to estimate the standard deviation of waiting time. The approximation requires only the mean and standard deviation or the coefficient of variation of the inter-arrival and service time distributions, and the number of servers. A spreadsheet model is specifically designed to analyze the variance of waiting time.

Casing damage problems are increasingly prominent in oil fields, most of which were caused by casing external squeezing loads. The traditional calculation method of casing external squeezing loads is not very accurate now, especially in complex formation. The purpose of this paper is to propose a new calculation method to solve the problem of actual casing loads under above conditions.

Based on Lame’s model of elastic mechanics, a new calculation method of casing external squeezing loads is deduced. Comprehensive influence laws of the loads which caused by in-situ stress, internal pressure, formation parameters, cement annulus parameters and casing parameters are analyzed.

The paper provides a new calculation method of casing external squeezing loads, by which the dispersion effect of internal liquid pressure caused by casing wall material is eliminated. The main influence factors of casing external squeezing loads are in-situ stress and formation elastic modulus.

The model and boundary conditions used in the paper is based on elastic mechanics. The accuracy of the calculation results depends on the quality and accuracy of the input formation parameters.

This paper proposes a new method to calculate casing external squeezing loads. And compared with traditional methods, this method is more practical.

This paper aims to propose a method for accurate radar echo simulation of wind turbines (WTs) array. It can solve the problem of passive interference from wind farms to neighboring radar stations.

First of all, the equivalent model of scattering centers of a single WT is obtained by using the spatial spectrum estimation method, and the accuracy of this model is verified by the scaled model experiment; then scattering centers model of WTs array was established by using the spatial coordinate transformation method. According to the position relationship between the model and the radar, and combined with the multipath scattering theory, the radar echo equation of WTs array was deduced. Finally, the simulation analysis is carried out with the four GoldWind 77/1500 WTs as an example and compared with the traditional methods.

This paper verifies the accuracy of the equivalent model of scattering centers through the WT scaled model experiment, and through simulation analysis, it is found that the result of this method is more consistent with the multipath scattering of radar echo between WTs array in practical engineering than the traditional method.

Based on the theory of high-frequency scattering, this paper introduces scattering centers into the solution of radar echo and considers the multipath scattering of radar echo, then a method for solving the radar echo of WTs array based on scattering centers is proposed.

The purpose of this paper is to study the variations of composition and properties of the passive film on 316 L stainless steel surface in 80°C, 0.5 mol L-1 H2SO4 + 2 mg L-1 NaF solution, is helpful to understand the mechanisms of corrosion resistancethe of plated Pd on 316 L ss.

The variations of composition and properties of the passive film on 316 L stainless steel surface in 80°C, 0.5 mol L-1 H2SO4 + 2 mg L-1 NaF solution after connected to Pd electrode were studied with methods of potential monitor, X-ray photoelectron spectroscopy analysis and electrochemical impedance spectrum (EIS) measurement.

By connecting to a Pd electrode, the potential of the SS sample increased from the active region to the passive region. By connecting to the Pd electrode, the contents of Cr, Cr(OH)3 and Fe3O4 in passive film increased obviously. With increased Pd/SS area ratio, the Cr(OH)3 content in passive film increased but the Fe3O4 content changed little. The results show that after connecting to Pd the corrosion resistance of the passive film on 316 L stainless steel increases obviously, which may be attributed to the more compact passive film because of higher Cr, Cr(OH)3 and Fe3O4 contents and less point defects in the film.

The effects and mechanism of Pd on passivation of SS was studied.

South Africa is the highest consumer of commercial energy per capita in Africa, ranking 16th in the world for primary energy consumption. It is also ranked among the bottom 50 of the 150 countries regarding energy efficiency. The cold chain is a large contributor through refrigerated transport vehicles. To comply with the changing climate regulations, cryogenic and eutectic systems are systems with great potential for small distance refrigerated transport. The purpose of this paper is to introduce eutectic system to medium distance refrigerated transport.

This study presents the potential use of Eutectic plates inside a medium refrigerated transport vehicle, by numerically investigating the characteristics of phase change material eutectic plates applied at low-temperature ranges. A physical model and a mathematical model for three-dimensional transient natural flow were developed as proposed by Xiaofeng and Zhang. Using the governing equation of mass, momentum and energy conservation, three Eutectic plate configurations were modeled and simulated in ANSYS Fluent for 5 h.

A uniform heat transfer and airflow condition inside a refrigerated compartment were predicted using the Reynolds stress model. The configuration with eutectic plates placed at the top and side showed great potential for the system functioning in the South African climate.

Medium refrigerated transport vehicle.

This configuration had a high-temperature distribution across the compartment and promoted high air circulations, showing that it could be ideal for medium refrigerated transport vehicles delivering perishable foodstuffs or non-food goods.

In this paper, the C80 special coal gondola car was taken as the subject, and the load test data of the car body at the center plate, side bearing and coupler measured on the dedicated line were broken down to generate the random load component spectrums of the car body under five working conditions, namely expansion, bouncing, rolling, torsion and pitching according to the typical motion attitude of the car body.

On the basis of processing the measured load data, the random load component spectrums were equivalently converted into sinusoidal load component spectrums for bench test based on the principle of pseudo-damage equivalence of load. Relying on the fatigue and vibration test bench of the whole railway wagon, by taking each sinusoidal load component spectrum as the simulation target, the time waveform replication (TWR) iteration technology was adopted to create the drive signal of each loading actuator required for the fatigue test of car body on the bench, and the drive signal was corrected based on the equivalence principle of measured stress fatigue damage to obtain the fatigue test loads of car body under various typical working conditions.

The fatigue test results on the test bench were substantially close to the measured test results on the line. According to the results, the relative error between the fatigue damage of the car body on the test bench and the measured damage on the line was within the range of −16.03%–27.14%.

The bench test results basically reproduced the fatigue damage of the key parts of the car body on the line.

This paper aims to analyse the role of government-led innovative knowledge management platforms in innovation knowledge management, social network effects and innovative resource clusters in the context of academician workstations in China. Specifically, this paper empirically studies the impact of academician workstations on corporate innovation capabilities and the mechanisms behind this impact.

This study uses the propensity matching score method and difference-in-differences method to test the relationship between academician workstations and corporate innovation capabilities. Baron and Kenny’s (1986) mediation method is used to test two potential mechanisms.

Academician workstations significantly improve corporate innovation capabilities because of their contribution to knowledge and innovation management. The facilitation effects are stronger in non-state-owned firms, high-tech firms and firms in industries with low levels of competition. Further, academician workstations enhance corporate innovation capabilities through their funding effect.

This paper encourages policymakers to create a better market environment and stable support policies to facilitate sustainable scientific and technological innovation.

To the best of authors’ knowledge, this study is among the first to empirically analyse the impacts of innovative knowledge management platforms on corporate innovation. It enriches the theoretical perspective of innovation platforms and provides an excellent research perspective for effectively analysing the impacts of innovation platforms. This study also contributes to the literature on the determinants of innovation.