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This study aims to investigate the rarefaction effects on flow and thermal performances of an equivalent sand-grain roughness model for aerodynamic thrust bearing.

In this study, a model of gas lubrication thrust bearing was established by modifying the wall roughness and considering rarefaction effect. The flow and lubrication characteristics of gas film were discussed based on the equivalent sand roughness model and rarefaction effect.

The boundary slip and the surface roughness effect lead to a decrease in gas film pressure and temperature, with a maximum decrease of 39.2% and 8.4%, respectively. The vortex effect present in the gas film is closely linked to the gas film’s pressure. Slip flow decreases the vortex effect, and an increase in roughness results in the development of slip flow. The increase of roughness leads to a decrease for the static and thermal characteristics.

This work uses the rarefaction effect and the equivalent sand roughness model to investigate the lubrication characteristics of gas thrust bearing. The results help to guide the selection of the surface roughness of rotor and bearing, so as to fully control the rarefaction effect and make use of it.

This study aims to investigate the thermohydrodynamic (THD) and thermoelastohydrodynamic (TEHD) performance of an air-lubricated thrust bearing under different slip conditions, especially the slip length effect.

In this study, a new modified boundary slip model was established to investigate thrust bearing performance. The THD and TEHD bearing characteristic distribution was analyzed with fluid–thermal–structure interaction approach. The effect of the slip length on the bearing performance was studied using various bearing structure parameters.

The increased slip length changed the classical feature distribution of the film pressure and temperature. The sacrifice of the bearing load capacity effectively compensated for the aerodynamic thermal effect and friction torque under the slip condition. The TEHD model has a lower film pressure and load capacity than the THD model. However, it also has lower film temperature, lower friction torque and smaller Knudsen number (Kn).

The bearing THD and TEHD performances of the modified boundary slip model were compared with those of a traditional no-slip bearing. The results help to guide the selection of the bearing surface materials and processing technology of rotor and foil, so as to fully control the degree of slip and make use of it.

Increasingly, Open Government Data (OGD), a philosophy and set of policies, gains on momentum today. Believed to promote transparency, accountability and value creation by making government data available to all (OECD, 2018), OGD constitutes a yet another field in which the interlocking relation between technological advances and politics can be studied. Using the national OGD portal of the Kingdom of Saudi Arabia (http://www.data.gov.sa/en) as a case study, this evaluates the portal to underline the significance of maintaining the quality of the data sets published online. The usability framework (Machova, Hub, & Lnenicka 2018) constitutes the framework for evaluation of the OGD portal. The findings suggest that there are many drivers to re-use the data sets published via the portal. At the same time, however, there are barriers to re-use the data sets on account of the non-publication of updated data sets. Implicitly, quality of the data sets should be improved. More involvement of the government agencies is required for contributing toward the data sets. Also, user involvement should be promoted by encouraging them to contribute to the data sets and lending recommendations for the improvisation of the data sets published via the portal.

This paper offers an alternative approach to assessing contagions in price and load in the Australian interconnected power markets. This approach enabled us to identify a high-risk region and assess the direction of contagions from both buyers' and sellers' perspectives.

The author used a multinomial logit method to measure contagions. Having identified the exceedance and coexceedances, the author estimated the multinomial logit coefficients of the covariates explaining the probability of a certain number of coexceedances.

Market participants should recognize the presence of contagion risk and scrutinize price and load dynamics in the NSW and VIC regions to anticipate any simultaneous extreme changes. Regulators need to stabilize the demand and supply sides in those regions to minimize any possible contagions.

This paper presents a pioneering study investigating contagion in the Australian interconnected power markets.

This study aims to investigate the impact and mechanism of new energy vehicle (NEV) information sources (IS) on mass consumers' purchase intentions (PIs) in China.

Around 902 valid questionnaires were collected using the questionnaire to analyze the different effects of three types of IS (official, interpersonal and commercial) on mass consumers' PIs. Besides, this study investigates the mechanisms by examining the mediating effect of perceived risk (PR) and the moderating effect of individual differences like age and education level.

The three types of NEV IS stimulate the PI of mass consumers, but there are some differences, with interpersonal information sources (IISs) having the strongest contribution, followed by official information sources (OISs) and commercial information sources (CISs) the least. Meanwhile, PR plays a mediating role in the effect of NEV IS on mass consumers' PIs, and age and education level moderate the influence paths. Specifically, the moderating effect of age mainly works on the negative impact of PR on PI, while education level moderates the influence of IS on PR.

This study contributes to filling the gaps in the current understanding of the role played by NEV IS in shaping consumer preferences and choices. It provides valuable insights for automotive manufacturers, policymakers and marketers to tailor their marketing strategies and improve information dissemination to effectively promote NEV adoption among mass consumers.

The purpose of this paper is to investigate whether management strategies implemented by non-commercial traders may be identified as a key factor in affecting oil price paths in the conventional pre- and post-financialization periods.

By using a vector autoregressive approach the dynamic analysis of the daily stock indexes for some of the most important world economies and the oil prices is conducted starting from 1992 to the end of 2020.

The findings do not support the idea that the financial markets act as a privileged conduit in transmitting the shocks to the oil spot quotations.

Such a direct assessment has not been previously proposed in literature wherein – under a financial perspective – the returns are generally taken into consideration.

Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed optical fiber sensing technology based on the temperature tracing method has been paid more attention due to its unique advantages of high sensitivity, good stability and high resolution. The purpose of this paper is to make a review of the existing related research, so as to facilitate the later scholars to understand and further study more systematically.

In this paper, three kinds of commonly used distributed fiber temperature measurement technologies are introduced. Based on the working principle, monitoring system, theoretical analysis, experimental research and engineering application of the fiber seepage monitoring technology, the present situation of dam seepage monitoring based on distributed fiber is reviewed in detail and their advantages and disadvantages are compared.

The thermal monitoring technology of seepage measurement depends on the accuracy of optical fiber temperature measurement (including the accuracy of the system and the rationality of the discrimination method), the correct installation of optical fiber and the quantitative analysis of temperature data. The accuracy of the current monitoring system can basically meet the existing measurement requirements, but the correct installation of optical fiber and the calibration of temperature data need to be further studied for different discrimination methods, and this field has great research value.

At present, there are many applications and research studies of optical fiber sensing in the field of structural health monitoring, and there are also reviews of related aspects. However, there is little or no review only in the field of seepage monitoring. This paper summarizes the research and application of optical fiber sensing in the field of seepage monitoring. The possibility of the gradient method to find its new prospect with the development of monitoring systems and the improvement of temperature resolution is discussed. The idea of extending the seepage monitoring method based on distributed optical fiber thermal monitoring technology to other monitoring fields is also given in the paper.

This paper aims to investigate empirically the linkages between stock and commodity futures markets.

It involves the application of a flexible copula approach to weekly total returns from the S&P 500 index and from three commodity sub-indices (agriculture, metals and energy) from 1995 to 2017.

Co-movement is by no means frequent and symmetric. It was predominantly zero before the last financial crisis, and since then, it is positive and asymmetric. The pattern of asymmetry is consistent with transmission of shocks under extreme negative shocks only. Recently, total returns of commodity futures are very poor. At the same time, commodity futures markets move in step (out of step) with stock markets when the latter plunge (rise), pointing to limited diversification benefits. These appear to justify the concerns of investors and researchers whether including commodities in a portfolio of assets is still a prudent investment strategy.

It is the only manuscript that combines a flexible copula approach and co-movement measurement along both the positive and negative diagonals. The findings are in sharp contrast with those reported by Delatte and Lopez (2013) and are very important for portfolio management.

This paper aims to investigate whether the best statistical model also corresponds to the best empirical performance in the volatility modeling of financialized commodity markets.

The authors use various p and q values in Value-at-Risk (VaR) GARCH(p, q) estimation and perform backtesting at different confidence levels, different out-of-sample periods and different data frequencies for eight financialized commodities.

They find that the best fitted GARCH(p,q) model tends to generate the best empirical performance for most financialized commodities. Their findings are consistent at different confidence levels and different out-of-sample periods. However, the strong results occur for both daily and weekly returns series. They obtain weak results for the monthly series.

Their research method is limited to the GARCH(p,q) model and the eight discussed financialized commodities.

They conclude that they should continue to rely on the log-likelihood statistical criteria for choosing a GARCH(p,q) model in financialized commodity markets for daily and weekly forecasting horizons.

The log-likelihood statistical criterion has strong predictive power in GARCH high-frequency data series (daily and weekly). This finding justifies the importance of using statistical criterion in financial market modeling.

First, this paper investigates whether the best statistical model corresponds to the best empirical performance. Second, this paper provides an indirect test for evaluating the accuracy of volatility modeling by using the VaR approach.

The purpose of this paper is to establish an appraisal system for evaluating and choosing traction battery for electric vehicle (EV) quantitatively and effectively.

Traction battery always bottlenecks the development of EV. It is difficult to evaluate and choose traction battery for EV because there are many kinds of battery and each kind has many performance parameters. An estimating system for traction battery was proposed with every factor considered. Analytic hierarchy process (AHP) and fuzzy comprehensive theory are both used to evaluate program with many aims and influencing factors. It is relatively easy and exact using AHP to determine the weighting value vector of every criterion but not so exact when marking the appraisal objects. Objections can be marked more reasonably with fuzzy comprehensive theory. Both the advantages of these two theories were integrated in this paper in order to evaluate battery more effectively. It was proved effective by the application example.

An estimating system and appraisal method for traction battery.

Weighing factors of different criteria should be determined based on the EV type and application condition.

Very useful method and system for EV designers to choose and evaluate traction battery.

The appraisal system eliminates the blindness when choosing and evaluating traction battery for EV. Both the merits of AHP and fuzzy comprehensive theory were combined for the evaluating process.