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For the dramatically developed high voltage direct current (HVDC) power transmission, HVDC cables play a vital role in the power transmission across seas and connections with renewable power sources. However, the condition monitoring of HVDC cables is still a challenging research topic. This paper aims to understand the influence of external factors, namely, current, cavity location and material properties, on partial discharge (PD) characteristics in HVDC cable in a numerical way referring to the refined Niemeyer’s model.

The influences of the three external factors are studied by a proposed numerical model for DC PDs based on the modification of a conventional PD model for AC voltage via a finite element analysis method.

The external factors can influence the discharge magnitude and discharge repetition rate via affecting the electrical conductivity of the material: DC PD is more frequent and with higher discharge magnitude when the cavity is closer to the conductor or the current through the conductor is higher. Both DC PD repetition rate and average discharge magnitude in long-term aged material are lower than virgin material. The effect of discharge on insulation degradation becomes decreasingly significant.

The current work is based on the numerical modelling of DC PDs. Further experimental validations and comparisons are essential for improving the model.

The studies of the influence factors for PDs under HVDC voltage can benefit the research and practical power transmission on DC PDs, contributing the design and test of DC PDs in HVDC cables, exploring the understandings of the DC PDs’ mechanism.

This paper, to the best of author’s knowledge, first studies the influence factors on DC PDs based on the numerical modelling work.

High voltage direct current (HVDC) cable is an important part in the electric power transmission and distribution systems. However, very little research has been carried out on partial discharge under direct current (DC) conditions. Niemeyer’s model has been widely used under alternating current (AC) conditions. This paper aims to intend to modify the Niemeyer’s model considering both electric field and charge dynamics under DC conditions, and therefore proposes a numerical model describing partial discharge characteristics in HVDC cable.

This paper intends to understand partial discharge characteristics under DC conditions through numerical modelling. Niemeyer’s model that has been widely used under AC conditions has been modified, taking both electric field and charge dynamics under DC conditions into consideration. The effects of loading level or current through the conductor, cavity location and material properties on partial discharges have also been studied.

Electrical conductivity is important in determining the characteristics of partial discharge under DC conditions and discharges tend to happen in short when the cavity field exceeds the inception level under the parameter values studied in the paper.

Building the numerical model is the purpose of the paper, and there is lack in experiment and the comparison between the simulation results and experiment.

The proposed model provides the numerical model describing partial discharge in HVDC cable and helps understand the partial discharge mechanism under DC voltage.

To the best of the author’s knowledge, this paper is a very early research on the numerical modelling work on partial discharge under DC voltage.

The purpose of this paper is to predict hospital respiratory system infection rate by using the gray GM(1,1) model, and to provide theoretical basis for the prospective study on hospital respiratory system infection management.

The annual respiratory system infection rate of a comprehensive third-class hospital in Yan’an is collected from 2011 to 2017. The GM(1,1) model is used for prediction, and mean absolute percentage error is used to evaluate the prediction accuracy of the model.

GM(1,1) statistical prediction model is established with good fitting degree and high reliability of extrapolation prediction.

The GM(1,1) model can well predict the respiratory system infection rate of the hospital.

This paper examines how firms respond to local government’s environment initiatives through textual analysis of government work reports (GWRs). This study aims to provide insights into how firms strategically respond to government’s environmental initiatives through their disclosure and investment practices.

This study uses a textual analysis of GWRs from China’s provinces. The frequency and change rate of environmental keywords in these reports are used as a measure of the government’s environmental initiatives.

This study finds that environmental disclosure scores in environmental, social and governance (ESG) reports increase with the frequency or change rate of environmental keywords in provincial GWRs. This effect is more pronounced for non-state-owned enterprises, firms in highly marketized provinces or those listed in a single capital market. However, there is no significant relationship between firms’ environmental investments and government initiatives, except for cross-listed firms in provinces with consistently high frequency of environmental keywords in their GWRs.

The findings indicate that government environmental initiatives can shape firms’ disclosure behaviors, yet have limited influence on investment decisions, suggesting that environmental disclosure could potentially be opportunistic. This underscores the need for more effective strategies to stimulate firms’ environmental investments.

This study provides valuable insights into the differential impacts of government environmental initiatives on firms’ disclosure and investment behaviors, contributing to the understanding of corporate environmental responsibility in the context of government initiatives.

The purpose of this paper is to examine the efforts of an ethnic Miao migrant worker association to recreate and engage with festivals both in the host society of the Pearl River Delta and back home in Southeastern Guizhou province of Southwest China. It analyzes how and under what conditions the disadvantaged migrant workers collectively demonstrate and assert their cultural identity in festival activities, rekindling and strengthening their ethnic consciousness.

Based on ethnographic field data, this study focuses on the connections between migrant workers’ lives in modern host societies and their traditional culture back home. Special attention is paid to the temporal dynamics of migrant workers’ cultural identity and socio-economic development.

The leaders of the Miao migrants’ association created network linkages to channel the flow of labor, capital and culture between the host society and the migrants’ hometown, and made efforts to secure institutional embeddedness at both ends of the flow. Their use of festivals and related heritage as cultural capital has facilitated the cultivation of network linkages and institutional embeddedness for economic advancement and overcoming ethnic prejudices and institutional disadvantages.

By illustrating how the economic development has been imbricated with culture, this research enhances understanding about the role of network linkage and institutional embeddedness in the flow of labor, capital and culture between host society and home place of migrant communities.

The purpose of this paper is to examine the relationship between dividend policy and earnings quality of Vietnamese listed firms.

The sample includes firms listed on Vietnam stock exchange during the period between 2010 and 2016. Two measures of earnings quality are the annual firm-specific absolute value of residuals from Dechow and Dichev’s (2002) model and from Dechow and Dichev (2002) as modified by McNichols’s (2002) model. The firms’ dividend policy is captured by dividend paying status. This is a dummy variable that takes the value of 1 if the firm pays dividends and 0 otherwise. In addition, dividend yield and dividend payout ratio, which are continuous variables, are also used in this paper as alternative proxies for dividend policy.

Using panel data analysis, this paper documents that dividend payers have higher earnings quality than dividend non-payers. Dividends are an indicator of earnings quality. These findings are consistent with prior studies. After controlling for variables that may be related to earnings quality as well as for the year and industry fixed effects, this relation remains unchanged. In addition, this result is also robust after controlling for firm fixed effects.

This paper offers the empirical evidence on the relation between dividend policy and earnings quality in Vietnam, which is a frontier market.

This study aimed to evaluate the cytotoxic/apoptotic effects of sweet apricot kernel ethanolic extract (SAEE) on human cancerous PANC-1 and 293/KDR normal cells.

The extract was prepared by maceration, and its chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The biological effects of SAEE on PANC-1 and 293/KDR cells were investigated using MTT (3–(4, 5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide) assay, DAPI (4',6-diamidino-2-phenylindole) and AnnexinV/propidium iodide (PI) staining. The expression of pro- and anti-apoptotic genes was evaluated by real-time quantitative polymerase chain reaction (real-time q-PCR) analysis.

The SAEE showed the selective growth inhibitory activity against PANC-1 cells with an IC50 (the 50% inhibitory concentration) value of about 1 mg/mL at 72 h. Further investigations by DAPI staining and flow cytometry revealed nucleus fragmentation and elevation of apoptotic cells, respectively. Also, a significant decrease in B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated x protein (Bax) ratio (0.41, p = 0.001) and the up-regulation of caspase-3 expression (1.5 fold, p = 0.002) indicated the induction of apoptosis in PANC-1 cells but not in 293/KDR non-cancerous cells. These results suggest that SAEE could induce apoptosis in cancer cells via a mitochondrial dependent pathway. Furthermore, GC-MS analysis showed that the SAEE is rich in γ-sitosterol and γ-tocopherol. Overall, the findings suggest that because of the selective impacts of SAEE on PANC-1 cells, it can be considered as a supportive care in adjuvant therapy for pancreatic cancer. However, the potent anticancer effects of main components of SAEE and its clinical value as an antitumor drug should be further investigated.

Considerable limitations of this study were that the related mechanisms of selective impacts of SAEE on cancerous and normal cells and potent cytotoxic/apoptotic effects of γ-sitosterol and γ-tocopherol as major components of SAEE were not investigated.

Recently, a growing interest has been dedicated to plant-based natural products. Sweet apricot kernel exerts a number of pharmacological activities; however, the anticancer effect, related mechanisms and its active compounds were rarely investigated. In this study, the authors aimed to evaluate the cytotoxic/apoptotic effects of SAEE on human cancerous PANC-1 and 293/KDR normal cells.

The mid-1990s marked a paradigm shift in the way physical activity is promoted, and walking is now considered the most suitable type of physical activity for widespread promotion. Accurate measurement underpins public health practice, hence the aims of this chapter are to: (1) provide a typology for the measurement of walking; (2) review methods to assess walking; (3) present challenges in defining walking measures; (4) identify issues in selecting instruments for the evaluation of walking and (5) discuss current efforts to overcome measurement challenges and methodological limitations. The taxonomy of walking indicates that secondary purpose walking is a more complex set of behaviours than primary purpose walks. It has many purposes and no specific domain or intensity, may lack regularity, and therefore poses greater measurement challenges. Objective measurement methods, such as accelerometers, pedometers, smartphones and other electronic devices, have shown good approximation for walking energy expenditure, but are indirect methods of walking assessment. Global Positioning System technology, the ‘Smartmat’ and radio-frequency identification tags are potential objective methods that can distinguish walkers, but also require complex analysis, are costly, and still need their measurement properties corroborated. Subjective direct methods, such as questionnaires, diaries and direct observation, provide the richest information on walking, especially short-term diaries, such as trip records and time use records, and are particularly useful for assessing secondary purpose walking. A unifying measure for health research, surveillance and health promotion would strongly advance the understanding of the impact of walking on health.

The increasing accumulation of synthetic plastic waste in oceans and landfills, along with the depletion of non-renewable fossil-based resources, has sparked environmental concerns and prompted the search for environmentally friendly alternatives. Biodegradable plastics derived from lignocellulosic materials are emerging as substitutes for synthetic plastics, offering significant potential to reduce landfill stress and minimise environmental impacts. This study highlights a sustainable and cost-effective solution by utilising agricultural residues and invasive plant materials as carbon substrates for the production of biopolymers, particularly polyhydroxybutyrate (PHB), through microbiological processes. Locally sourced residual materials were preferred to reduce transportation costs and ensure accessibility. The selection of suitable residue streams was based on various criteria, including strength properties, cellulose content, low ash and lignin content, affordability, non-toxicity, biocompatibility, shelf-life, mechanical and physical properties, short maturation period, antibacterial properties and compatibility with global food security. Life cycle assessments confirm that PHB dramatically lowers CO₂ emissions compared to traditional plastics, while the growing use of lignocellulosic biomass in biopolymeric applications offers renewable and readily available resources. Governments worldwide are increasingly inclined to develop comprehensive bioeconomy policies and specialised bioplastics initiatives, driven by customer acceptability and the rising demand for environmentally friendly solutions. The implications of climate change, price volatility in fossil materials, and the imperative to reduce dependence on fossil resources further contribute to the desirability of biopolymers. The study involves fermentation, turbidity measurements, extraction and purification of PHB, and the manufacturing and testing of composite biopolymers using various physical, mechanical and chemical tests.

Domain integrals, known as volume potentials in 3D elasticity problems, exist in many boundary-type methods, such as the boundary element method (BEM) for inhomogeneous partial differential equations. The purpose of this paper is to develop an accurate and reliable technique to effectively evaluate the volume potentials in 3D elasticity problems.

An adaptive background cell-based domain integration method is proposed for treatment of volume potentials in 3D elasticity problems. The background cells are constructed from the information of the boundary elements based on an oct-tree structure, and the domain integrals are evaluated over the cells rather than volume elements. The cells that contain the boundary elements can be subdivided into smaller sub-cells adaptively according to the sizes and levels of the boundary elements. The fast multipole method (FMM) is further applied in the proposed method to reduce the time complexity of large-scale computation.

The method is a boundary-only discretization method, and it can be applied in the BEM easily. Much computational time is saved by coupling with the FMM. Numerical examples demonstrate the accuracy and efficiency of the proposed method..

Boundary elements are used to create adaptive background cells, and domain integrals are evaluated over the cells rather than volume elements. Large-scale computation is made possible by coupling with the FMM.