Search Results (5)

Background: Informal welders in Pretoria West face growing occupational safety risks due to hazardous working environments and limited regulatory oversight. Despite the high-risk nature of their work, many remain unaware of relevant safety legislation and inconsistently use personal protective equipment (PPE). This study aimed to investigate the occupational safety risks, challenges, and levels of compliance with safety practices among informal welders in Pretoria West, South Africa. Methods: A cross-sectional mixed-methods approach was employed, incorporating both qualitative and quantitative designs. Data were collected from 40 male welders (aged 20–55 years) using structured questionnaires, observational checklists, and semi-structured interviews. Descriptive statistics were generated using Microsoft Excel, while thematic content analysis was applied to the qualitative data. Results: Eighty-five percent (85%) of welders reported using gas welding, and more than half had received training in welding and PPE use; however, 47.5% had no formal training. A high prevalence of work-related injuries was reported, including burns, cuts, and eye damage. Common safety concerns identified were burns (42.5%), electric shocks (35%), and malfunctioning equipment. Observational data revealed inconsistent PPE use, particularly with flame-resistant overalls and eye protection. Qualitative insights highlighted challenges such as demanding client expectations, hazardous physical environments, and inadequate equipment maintenance. Many sites lacked compliance with occupational safety standards. Conclusion: The study reveals critical gaps in safety knowledge, training, and PPE compliance among informal welders. These deficiencies significantly elevate the risk of occupational injuries. Strengthening occupational health and safety regulations, improving access to PPE, and delivering targeted training interventions are essential to safeguard the well-being of welders and those in their surrounding communities. Full article

To address the limitations of current DC residual current protection methods, which primarily rely on the amplitude of DC residual current for fault detection and fail to safeguard against electric shocks at two points on the same side in DC Isolated Terra (IT) System systems, this paper introduces a novel protection method based on DC electric shock features. This paper first analyzes the sliding curvature accumulation and peak rise time features of DC basic residual current, load mutation current, and animal body electric shock current under multi-factor conditions. The analysis shows that sliding curvature accumulation in the range of 0.1 ≤ K ≤ 1 and a peak rise time of Δt ≥ 20 ms can effectively distinguish animal body electric shock. Then, based on this electric shock’s distinctive characteristics, an approach for identifying types of electric shock is developed. Finally, a DC residual current protective device (DC-RCD) is designed. The prototype test results demonstrate that the DC-RCD has an action time of t_s < 70 ms. The proposed method accurately provides protection against electric shocks and effectively addresses the issue of inadequate protection when two fault points occur on the same side within an IT system. This approach holds significant reference value for the development of next-generation DC-RCDs. Full article

The growing demand for personal mobility is leading to an increase in vehicle use, which is in turn contributing to higher carbon emissions. It is widely acknowledged that emission-free electric vehicles (EVs) will play a pivotal role in the decarbonization process, particularly in the decarbonization of transport systems. The objective of this paper was to present the trends in demand for electric vehicles (EVs) in Poland, together with the identification of market shocks and an assessment of the programs supporting electromobility. The number of imported and domestically purchased new and used electric vehicle (BEV) registrations was analyzed using the TRAMO-SEATS and ARIMA-X-12 seasonal adjustment methods. The rise in sales of electric vehicles in Poland was driven by the government’s electromobility support programs and alterations to tax legislation, with no discernible seasonal impact. The number of registrations in Poland increased significantly, exhibiting an upward trajectory. However, this growth is constrained by the inadequate number of charging stations, which are primarily powered by electricity derived from coal. Consequently, while the development of electromobility in Poland is evident, the decarbonization process remains a challenge. Full article

Introduction: The aim of the study was to assess the prevalence of frailty among elderly patients who had an implanted cardioverter defibrillator, as well as the influence of frailty on the main endpoints during the follow-up. Methods: The study included 103 patients > 60 years of age (85M, aged 71.56–8.17 years). All of the patients had an implanted single or dual-chamber cardioverter-defibrillator. In the research, there was a 12-month follow-up. The occurrence of frailty syndrome was assessed using the Tilburg Frailty Indicator scale (TFI). Results: Frailty syndrome was diagnosed in 75.73% of the patients that were included in the study. The mean values of the TFI were 6.55 ± 2.67, in the physical domain 4.06 ± 1.79, in the psychological domain 2.06 ± 1.10, and in the social domain 0.44 ± 0.55. During the follow-up period, 27.2% of patients had a defibrillator cardioverter electric shock, which occurred statistically more often in patients with diagnosed frailty syndrome (34.6%) compared to the robust patients (4%); p = 0.0062. In the logistic regression, frailty (OR: 1.203, 95% CI:1.0126–1.4298; p < 0.030) was an independent predictor of a defibrillator cardioverter electric shock. Similarly, in the logistic regression, frailty (OR: 1.3623, 95% CI:1.0290–1.8035; p = 0.019) was also an independent predictor for inadequate electric shocks. Conclusion: About three-quarters of the elderly patients that had qualified for ICD implantation were affected by frailty syndrome. In the frailty subgroup, adequate and inadequate shocks occurred more often compared to the robust patients. Full article

The mode transition from electric propulsion mode to hybrid propulsion mode is important with regard to the power management strategy of plug-in hybrid electric vehicles (PHEVs). This is because mode transitions can occur frequently depending on the power management strategies and driving cycles, and because inadequate mode transitions worsen the fuel efficiency and drivability. A pre-transmission parallel PHEV uses a clutch between the internal combustion engine (ICE) and the electric motor (EM) to connect or disconnect the power source of the ICE for a mode transition. The mode transition requires additional energy consumption for clutch speed synchronization, and is accompanied by a drivetrain shock due to clutch engagement. This paper proposes a control strategy for the mode transition with gear-shifting to resolve the problems of energy consumption and drivetrain shock. Through the development of a PHEV performance simulator, we analyze the mode transition characteristics and propose a control strategy considering the vehicle acceleration and gear state. The control strategy reduces the duration required for the mode transition by moving the start time of the mode transition. This helps to improve energy efficiency while maintaining adequate drivability. Full article