Electric power quality and ship accidents

Peer Reviewe

The improvement of compensating current generation algorithms in active power filtering

Peer Reviewe

Comparison of reorganized versus unaltered cardiology departments during the COVID-19 era: a subanalysis of the COV-HF-SIRIO 6 study

Background: Since the beginning of the coronavirus disease-2019 (COVID-19) pandemic, numerous cardiology departments were reorganized to provide care for COVID-19 patients. We aimed to compare the impact of the COVID-19 pandemic on hospital admissions and in-hospital mortality in reorganized vs. unaltered cardiology departments. Methods: The present subanalysis is a multicenter retrospective COV-HF-SIRIO 6 study that includes all patients (n = 101,433) hospitalized in 24 cardiology departments in Poland between January 1, 2019 and December 31, 2020, with a focus on patients with acute heart failure (AHF). Results: Reduction of all-cause hospitalizations was 50.6% vs. 21.3% for reorganized vs. unaltered cardiology departments in 2020 vs. 2019, respectively (p < 0.0001). Considering AHF alone respective reductions by 46.5% and 15.2% were registered (p < 0.0001). A higher percentage of patients was brought in by ambulance to reorganized vs. unaltered cardiology departments (51.7% vs. 34.6%; p < 0.0001) alongside with a lower rate of self-referrals (45.7% vs. 58.4%; p < 0.0001). The rate of all-cause in-hospital mortality in AHF patients was higher in reorganized than unaltered cardiology departments (10.9% vs. 6.4%; p < 0.0001). After the exclusion of patients with concomitant COVID-19, the mortality rates did not differ significantly (6.9% vs. 6.4%; p = 0.55). Conclusions: In cardiology departments reorganized to provide care for COVID-19 patients vs. unaltered ones, observed: i) a greater reduction in hospital admissions in 2020 vs. 2019; ii) higher rates of patients brought by ambulance and lower rates of self-referrals; and iii) higher all-cause in-hospital mortality for AHF due to COVID-19 related deaths

Electric power quality and ship accidents

Peer Reviewe

Electric power quality and ship accidents

Peer Reviewe

Case Study—Based Overview of Some Contemporary Challenges to Power Quality in Ship Systems

The content of this paper consists of a presentation and discussion on a case study-based overview of some selected challenges dealing with a problem of power quality on ships. As a consequence, the theoretical considerations are aided by experimental results based mainly on the author’s research team experience and achievements. Two basic aspects, assessment and improvement of power quality are taken into account. In the process of power quality assessment, the existing ambiguities are analyzed and discussed, after that the undertaken measures and challenges to overcome them are presented. The ways of improving of power quality on ships are described and analyzed in two layers: technological solutions and the staff competences. Expectations and challenges for the future based on developments of both, legal and professional aspects are focused on the key question: how to reduce a risk of ship accidents. Finally, the future works as well as the concluding remarks are formulated and commented on

Study on the Hazard Limitation of Hybrid Circuit Breaker Actuator Operation

The paper deals with a key issue, how to limit the hazard and assure reliability, safety and repeatability of operation of selected critical devices protecting electrical power systems. The main research is focused on the incorrect operation of hybrid switches caused by random disturbances of the thyristor gate signals in the electrodynamic drive coil power supply circuit. Firstly, a pilot experiment on the operation of hybrid circuit breaker actuators under random disturbance conditions was carried out and the results are presented. Next, an in-depth operation analysis, based on experimental and simulation research, according to setting conditions of the circuit breaker actuator parameters such as capacitance, voltage and switching time was performed. A simulation study with the use of a field–circumferential model in the Ansys Maxwell program of electrodynamic propulsion of rectilinear motion, which enables energy transfer from the capacitor bank to the actuator coil power supply at selected time intervals, was executed. The study analysed the impact of the discontinuity of energy transfer on the dynamic properties of the actuator and some recommendations for designers and users on how to limit this hazard are formulated

New Approach to Analysis of Selected Measurement and Monitoring Systems Solutions in Ship Technology

This paper is dedicated to certain types of measurement in ship systems, analyzed based on selected case studies. In the introductory part, a simplified structure of a modern cargo ship as an object of measurement and control is presented. Next, the role of measurement in the ship’s operation process is described and commented on, with focus on specifics of local and remote control, both manual and automatic. The key part of the paper is dedicated to a short overview of selected examples of measuring and monitoring systems. The basic criteria for the aforementioned selection are the vital role of the considered systems for safe and effective ship operation as well as documented innovative contribution of Gdynia Maritime University (GMU) in development of the state-of-the-art in the analysed area of measurement. Based on these criteria, the monitoring of operational parameters of main engine and temperature measurement in the ships hazardous areas have been chosen. The aforementioned measurement and monitoring systems are analysed, taking into account both innovation of technical solutions together with their ship technology environment conditions and related legal requirements. Finally, some concluding remarks are formulated