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Oil-water two-phase flow is the most prevalent medium in oil field gathering pipelines, and the corrosion of pipelines is often highly localized. Therefore, the purpose of this paper is to investigate the corrosion behavior of 20# pipeline steel in the oil-water stratified liquids, vary the water content of the upper emulsion and study the difference of the corrosion process.

Combine the wire beam electrodes (WBE) technique and the corrosion weight loss method to investigate the corrosion behavior of 20# steel in produced water simulation fluid and oil-water stratified liquids, and a corrosion mechanism model was established for analysis and explanation.

The results of mass loss experiments showed that the average corrosion rate increased with the increase in the water content of the upper emulsion. The corrosion current distribution maps indicated that the most serious corrosion occurred in the produced water simulation liquid, and the corrosion process showed the law of waterline corrosion. In addition, it was also found that the corrosion of the WBE in the stratified liquids had obvious non-uniformities. The electrode wires at the oil-water interface suffered from severe corrosion, caused by the dissolution of crude oil acids in water and the uneven distribution of oxygen in the corrosive medium.

The WBE technique provides a deep insight into the corrosion phenomena at the oil-water interface, which is helpful for characterization of the non-uniformity of corrosion parameters and evaluating the risks of multiphase corrosive media.

Aiming at the inefficiency of solving the Sobol index using the traditional mathematical analytical method, a Sobol global sensitivity analysis method is proposed.

In this paper, a support vector regression (SVR) surrogate model is constructed to solve the Sobol index. The optimal combination of SVR hyperparameters is obtained by using the improved beluga whale optimization (IBWO). Meanwhile, in order to solve the problem that Sobol sequences will form correlation regions in high-dimensional space leading to the uneven distribution of sampling points, a scrambled strategy is introduced in the Sobol sensitivity analysis using IBWO-SVR. Thus, the IBWO-SVR-SS sensitivity analysis model is established.

The results of two test functions show that the method further improves the accuracy of the sensitivity analysis. Finally, the first-order Sobol index and second-order Sobol index are solved by the IBWO-SVR-SS method using the metro bogie frame as an engineering example. Through the analysis results, the key design parameters of the frame and the design parameter combinations with more obvious coupling relationships are identified, providing a strong reference for the subsequent analysis and structural optimization.

Sobol sensitivity analysis using the surrogate model method can effectively improve the efficiency of the solution. In addition, IBWO is used for the optimization of the SVR hyperparameters to improve the accuracy and efficiency of the optimization, and finally, the correction of the Sobol sequence through the introduction of the disruption strategy also further improves the accuracy of the sensitivity analysis of Sobol.

The purpose of this paper is to understand whether the personal capital of the entrepreneur positively or negatively affects outcomes from self-employment.

Data from the UK’s longitudinal household surveys (BHPS, UKLHS) between 1991 and 2014 were analysed. Relationships between age, education, health and family status, income earned and hours worked were tested.

Entrepreneurs with higher levels of personal capital enjoyed higher incomes. However, those with lower levels of personal capital were more likely to have negative returns from self-employment, and so experience it as “self-exploitation”.

A basis for understanding different outcomes from self-employment was developed and tested.

Specific characteristics of continuing and new entrepreneurs were identified that are positively associated with beneficial outcomes from self-employment.

Positive and negative outcomes from self-employment are explained. The notion of personal capital is developed as an explanatory framework for variable outcomes from self-employment.

The purpose of this paper is to examine the effectiveness of a holistic school-based nutrition programme using the health-promoting school (HPS) approach, on teachers’ knowledge, attitudes and behaviour in relation to nutrition in rural China.

A cluster-randomised intervention trial design was employed. Two middle schools were randomly selected and assigned to either the intervention school using the HPS framework (HPS School), or to the Control School, in Miyun County, Beijing. From each school 20 teachers were randomly selected to complete the survey. Nutrition-related knowledge, attitudes and behaviour were measured at pre- and post-intervention surveys with the same instrument. The nutrition intervention last for six months.

The holistic school-based nutrition programme using the HPS framework had no statistical impact on improving teacher’s knowledge, attitudes and behaviour in relation to nutrition (p > 0.05).

Future holistic school-based nutrition programmes targeting adolescents should also design and implement longer and more intensive interventions for teachers focusing on how to equip them with the awareness and ability to disseminate their knowledge, positive attitudes and role model behaviours to students, rather than on how to teach them basic knowledge and skills.

Although teachers play a critical role in the HPS framework, there is very limited published research investigating the change in teachers’ nutrition-related knowledge, attitudes and behaviour as a result of a nutrition promotion programme.

The purpose of this paper is to improve adolescents’ nutrition knowledge and to examine the effect of interventions component to improve adolescents’ nutrition knowledge.

The study design was multi-factorial with repeated measures, at two points in time, of dependent samples from three schools, which were randomly selected from 15 middle schools in Miyun County, Beijing, and then randomly assigned to control school or intervention school. The instrument for baseline survey was a 14-item and for follow-up survey was a 26-item, self-administered, structured questionnaire, designed in Chinese.

Students’ nutrition knowledge improved significantly in intervention schools after intervention compared with controls. The extent to which students felt that peer support activities were helpful and that what they learned in class about nutrition was helpful, was related to their resultant level of nutrition knowledge.

To the authors’ knowledge there have been no previous studies which explore the effect of specific intervention components on levels of nutrition knowledge among adolescents.

The purpose of this paper is to investigate the determinants of self-employment, using data from the British Household Panel Survey.

Using the maximum likelihood estimation, the authors estimate the Probit models via disaggregation of the sample by male and female, and inclusion of regional and industrial controls.

This paper finds that the intergenerational links in self-employment run significantly through father-son, and mother-daughter. In addition, the authors find that lump-sum endowment, aspiration, marriage and education attainment are all significant and positive determinants for female self-employed while insignificant for male self-employed. Variables including number of children, health of the individual, and age effect are more important determinants for male than for female self-employed.

The findings show that there are significant differences between male and female self-employed. Future studies on self-employment should therefore distinguish the two genders in their econometric models.

The authors reinforce and add to the exiting literature on gender differences in the determinants of self-employment. The authors disaggregate the data by gender, and introduce some important variables for empirical studies, such as father self-employed, mother self-employed, aspiration, health of the individual, and age effect.

This study aims to explore the impact of carbon neutral announcements on “stock market value” of publicly listed companies in China.

The event study approach is adopted. Market, market-adjusted, Carhart four-factor model and a cross-sectional regression model are employed to examine the impacts of carbon neutral announcements on “stock market value” of Chinese companies based on data from 188 carbon neutral announcements.

Carbon neutral announcements positively impact Chinese shareholder value. Carbon neutral announcements at the strategic level have a more positive and significant impact on Chinese stock market value. Innovative carbon neutral announcements do not significantly cause Chinese stock market reactions. Companies have more positive and significant stock market reactions when the companies make carbon neutral announcements that reflect high supply chain network resilience and heterogeneity and strong supply chain network relationships.

The findings uncover the business value of carbon neutral activities and provide operations managers in developing countries insights into how to improve enterprises' market value by actively implementing carbon neutral activities.

This paper is the first trial to apply an event study to examine the relationship between carbon neutral announcements and Chinese stock market value from the perspective of announcement level and type and supply chain networks. This paper introduces corporate reputation theory and enriches the application of corporate reputation theory in the field of low-carbon environmental protections and supply chains.

The purpose of this paper is to solve the tracking problem for free-floating space manipulators (FFSMs) in task space with parameter uncertainties and external disturbance.

In this paper, the novel cerebellar model articulation controller (CMAC) is designed with the feedback controller. More precisely, the parameter uncertainties in the FFSM are considered for achieving the robustness.

By using the dynamically equivalent model, the CMAC can be designed and trained with the desired performance, such that the prescribed trajectory can be followed accordingly. The simulation results are presented for illustrating the validity of the derived results.

Based on the designed CMAC, the tracking error would be approaching zero by choosing appropriate quantization level in CMAC and the corresponding learning rules can be tuned online.

The purpose of this paper is to explore the factors that influence migrant workers' household registration transfer willingness at both individual and urban levels and to provide empirical evidence on adjusting the household registration system to accommodate economic development and migrant workers' imbalances.

This paper adopts a hierarchical nonlinear model and examines individual and urban influencing factors of migrant workers' household registration transfer willingness, based on the data from China Migrants Dynamic Survey (CMDS) and the Urban Statistical Yearbooks.

This paper shows that: (1) multi-factors, such as age, education, marital status, household demographics, industry and migrant workers' contract coverage, have significant effects on migrant workers' household registration transfer willingness; (2) The urban public service equalization indicators, such as regional economic, educational resources, medical care and ecological quality, have significant effects on migrant workers' willingness to transfer household registration; (3) The heterogeneity of migrant workers' willingness to transfer household registration is significant in central, eastern and western China.

The authors provide a fresh perspective on population migration research in China and other countries worldwide based on the pull–push migration theory, which incorporates both individual and macro (urban) factors, enabling a comprehensive examination of the factors influencing household registration transfer willingness. This hierarchical ideology and approach (hierarchical nonlinear model) could be extended to investigate the influencing factors of various other human intentions and behaviors.

Micro approaches (individual perspective) have dominated existing studies examining the factors influencing migrant workers' household registration transfer willingness. The authors combine individual and urban perspectives and adopt a more comprehensive hierarchical nonlinear model to extend the empirical evidence and provide theoretical explanations for the above issues.