Search results

The water-lubricated hydrodynamic herringbone groove journal bearing (HGJB) is capable of running at high speed. However, when running at a low speed, it suffers from a low load-carrying capacity due to the weak hydrodynamic effect. To overcome this problem, this study proposes a hybrid water-lubricated HGJB and aims to investigate its dynamic characteristics.

A hybrid lubrication model applicable to the hybrid water-lubricated HGJB is established based on the boundary fitted coordinate system, which considers the turbulent, thermal and tilting effects, and the finite difference method is used to calculate the dynamic characteristics of the hybrid water-lubricated HGJB.

The result shows that the hybrid HGJB has larger dynamic coefficients and better system stability compared with the hydrodynamic HGJB when running at low speed. Furthermore, the stiffness of hybrid HGJB are mainly governed by the hydrodynamic effect rather than the hydrostatic effect when running at high speed.

The proposed hybrid water-lubricated HGJB shows excellent dynamic characteristics at either low speed or high speed; and the hybrid water-lubricated HGJB has a large load-carrying capacity when running at low speed and has a good dynamic stability when running at high speed.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0233/

Comprehensive project portfolio risk (PPR) analysis is essential for the success and sustainable development of project portfolios (PPs). However, project interdependency creates complexity for PPR analysis. In this study, considering the interdependency effect among projects, the authors develop a quantitative evaluation model to analyze PPR based on a fuzzy Bayesian network.

In this paper, the primary purpose is to comprehensively evaluate project portfolio risk considering the interdependency effect using a systematical model. Accordingly, a fuzzy Bayesian network (FBN) is developed based on the existing studies. Specifically, first, the risks in project portfolios are identified from the project interdependencies perspective. Second, a fuzzy Bayesian network is adopted to model and quantify the interaction relationships among risks. Finally, the model is implemented to analyze the occurrence situation and characteristics of risks.

The interdependency effect can lead to high-stake risks, including weak financial liquidity, a lack of cross-project members and project priority imbalance. Furthermore, project schedule risks and inconsistency between product supply and market demand are relatively sensitive and should also be prioritized. Also, the validity of this risk evaluation model has been proved.

The findings identify the most sensitive risks for guaranteeing portfolio implementation and reveal interdependency effect can trigger some specific risks more often. This study proposes for the first time to measure and analyze project portfolio risk by a systematical model. It can help systematically assess and manage the complicated and interdependent risks associated with project portfolios.

External stakeholder risks (ESRs) caused by unfavorable behaviors hinder the success of project portfolios (PPs). However, due to complex project dependency and numerous risk causality in PPs, assessing ESRs is difficult. This research aims to solve this problem by developing an ESR-PP two-layer fuzzy Bayesian network (FBN) model.

A two-layer FBN model for evaluating ESRs with risk causality and project dependency is proposed. The directed acyclic graph (DAG) of an ESR-PP network is first constructed, and the conditional probability tables (CPTs) of the two-layer network are further presented. Next, based on the fuzzy Bayesian network, key variables and the impact of ESRs are assessed and analyzed by using GeNIe2.3. Finally, a numerical example is used to demonstrate and verify the application of the proposed model.

The proposed model is a useable and effective approach for ESR assessment while considering risk causality and project dependency in PPs. The impact of ESRs on PP can be calculated to determine whether to control risk, and the most critical and heavily contributing risks and project(s) in the developed model are identified based on this.

This study extends prior research on PP risk in terms of stakeholders. ESRs that have received limited attention in the past are explored from an interaction perspective in the PP domain. A new two-layer FBN model considering risk causality and project dependency is proposed, which can synthesize different dependencies between projects.

The primary objective of this research is to explore the impact of the repeated two-syllable communication strategy on the interaction effectiveness between AI and customers.

This study adopts an experimental research methodology to investigate the role of the repeated two-syllable communication strategy employed by AI customer service agents.

Study 1 shows that AI agents using the repeated two-syllable strategy enhance the interaction effectiveness between AI and customers. Study 2 identifies humanization perception as a key factor linking the strategy to better interaction effectiveness. Study 3 highlights how consumer materialism moderates this effect, while Study 4 examines how the type of agent (AI vs. human) influences the results.

This study extends the application of AI communication strategies in interactive marketing, specifically how AI agents enhance consumer interaction through repeated two-syllable communication. It pioneers the exploration of AI-human interaction, enriching the humanization theory by revealing how AI can evoke emotional responses. The study also integrates consumer materialism as a moderating factor, offering new theoretical and practical insights for brands to optimize AI-customer service interactions and improve engagement in real-world marketing contexts.

This study aims to argue that responses in economic growth (EG) resulting from positive and negative shocks in energy consumption could be a non-linear phenomenon. Thus, the study aims to investigate the existence of non-linear long-run effects of positive and negative shocks in green and conventional energy consumption on EG for China and India. By decomposing energy consumption in positive and negative shocks, the study seeks to determine the distinct impact of positive and negative shocks in energy (conventional and green) consumption on EG of China and India.

A non-linear autoregressive distributed lag (NARDL) model based on energy-augmented environment Kuznets curve (EKC) framework is used on annual time series covering the period 1965–2021. The study uses a precise econometric methodology, starting with unit root tests to assess stationarity, moving to the estimation of the NARDL model, which resulted in the calculation of long-run coefficients and error correction terms to analyse the rate of adjustment towards equilibrium.

The empirical findings demonstrate that there exists a non-linear cointegrating relationship among EG, carbon emissions and green and conventional energy consumption for both economies. In the long run, a non-linear impact of green energy consumption (GEC) on EG is evident for China only, whereas non-linear impact of conventional energy consumption (CEC) on EG is visible for both countries.

While China and India prioritise energy diversification by embracing green energy to promote energy security and limit rising carbon emissions, it is interesting to investigate how positive and negative shocks in GEC and CEC have affected their EG. Second, this paper examines the trade-offs between EG and GEC/CEC in China and India, two high-carbon emitters. The disparities in trade-offs may indicate how well each country’s energy policies address increased EG with fewer energy-induced carbon emissions.

This study examines non-linear cointegration among the variables of interest, whereas most prior studies have focused on linear cointegration. The existence of non-linear cointegration may suggest that positive and negative shocks in GEC and CEC can result in non-linear reactions in EG. Thus, it establishes a basis for examining the non-linear long-term effects of GEC and CEC on EG. The research findings indicate significant consequences and necessitate prompt intervention to alleviate the detrimental impacts of shocks in GEC and CEC on EG in China and India and provide several important inputs to address the inherent challenges of energy transition goals.

The purpose of this study is to establish a fractal model of thermal contact conductance (TCC) of micro-segment gear considering friction coefficient.

The influences of friction coefficient, fractal dimension, fractal roughness and contact type on the TCC of the rough surface were studied by using numerical simulation.

The results show that with the increase of the friction coefficient, the TCC of the rough surface will decrease. As the fractal dimension increases or the fractal roughness decreases, the rough surface becomes smoother and the TCC becomes larger. Under the same load conditions, the TCC of the internal contact type is greater than that of the external contact type. In engineering practice, the desired TCC can be achieved by changing the contact type.

A fractal model of TCC of micro-segment gear considering friction coefficient was established in this study. The achievements of this study provide some theoretical basis for the investigation of the TCC of the gear.

The purpose of this study is to establish a thermal contact conductance model of rough surfaces with inclination based on three-dimensional fractal theory.

The effects of contact load, inclination angle, fractal dimensional and fractal roughness on thermal contact conductance of rough surfaces were studied using numerical simulation.

The results show that the thermal contact conductance of the rough surface increases with the increase of contact load and fractal dimension and decreases with the increase of fractal roughness and inclination angle. The inclination angle of the rough surface has an important influence on the thermal contact conductance of the rough, and it is a factor that cannot be ignored in the study of the thermal contact conductance of rough surfaces.

A thermal contact conductance model of rough surfaces with inclination based on three-dimensional fractal theory was established in this study. The achievements of this study provide some theoretical basis for the investigation of the thermal contact conductance of rough surfaces.