Ways residents of large cities in Poland, commute before and during the Covid-19 pandemic

PURPOSE: The article concerns the issues related to the methods of movement of people in urban areas by means of cars, trams, buses, bicycles, e-scooters, electric scooters and on foot. Its purpose is to present selected factors determining this choice.DESIGN/METHODOLOGY/APPROACH: The authors, using the proprietary questionnaire, conducted a survey among the inhabitants of one of the largest cities in Poland - Szczecin to determine their current preferences related to the way of movement before and during the pandemic caused by the Covid-19 virus. Non-parametric dual and multiple comparison tests, the Mann-Whitney U test and the Kruskal-Wallis rank ANOVA were performed. The Cronbach's α coefficient was used to assess the reliability of the measuring scale.FINDINGS: The conducted analyzes allowed to determine the most common ways of traveling, the level of their safety and accessibility for residents. Statistically significant differences were found in respondents' opinions, depending on age, gender, industry, and education. The impact of the Covid-19 pandemic on opinions on the frequency of use, safety, and availability of means of transport in Szczecin was verified. The analysis showed a slight decrease in the declared frequency of using the analyzed means of transport and no decrease in the safety assessment of the analyzed means of transport during the application of the restrictions related to Covid-19.PRACTICAL IMPLICATIONS: The presented analysis and assessment of the ways in which the inhabitants of Szczecin move could be used in rational actions of the local authorities aimed at improving the quality of life of the inhabitants and friendly to the inhabitants of the city in the context of public and individual transport.ORIGINALITY/VALUE: The authors compared the preferences of the ways of movement and the implemented solutions with the parameters of their effectiveness, based on the experimental results and foreign literature.peer-reviewe

Identification of threats in the supply chain of a production process

PURPOSE: Economic growth, along with aggressive competition, directly influences the functioning of supply chains and equally shapes all internal and external threats. This publication aims to present the identification process and analyse the significance of threats in supply chains at the stage of the production process of structural elements.DESIGN/METHODOLOGY/APPROACH: An appropriate questionnaire and checklist have been developed to determine the frequency of threats. The analysis of measurement scale reliability was performed using the α-Cronbach coefficient and Guttman split-half method. Finally, the research results were analysed using the proprietary ranking method based on the adopted measurement scale.FINDINGS: The empirical results indicate that the survey conducted using the adopted questionnaire and the checklist allows for identifying threats in the supply chains occurring in the manufacturing process. In contrast, the frequencies of threat occurrence determined using a survey questionnaire allow for appropriate ranking.PRACTICAL IMPLICATIONS: The study should be treated as a pilot for a group of medium-sized manufacturing companies implementing a sustainable development policy.ORIGINALITY/VALUE: Threat assessment in production processes and supply chains can have a practical impact on shaping enterprises' policy of sustainable development.peer-reviewe

The use of neural networks for modeling the movement of surface water masses in enclosed sea areas

PURPOSE: The article presents the use of neural networks to predict the parameters of the movement of surface water masses in enclosed sea areas.DESIGN/METHODOLOGY/APPROACH: The input data were meteorological parameters recorded at the stations Trzebież and Świnoujscie. The output data were the parameters of moving drifters, obtained because of an experiment in 2018 in the waters of the Szczecin Lagoon. The model uses Multi-Layer Perceptron networks with different activation functions. As a criterion for selecting the best networks, the highest correlation statistics for the test and validation sample were used.FINDINGS: As a result of the research, predictions of the speed and direction of surface water masses were obtained based on the meteorological conditions recorded on the outskirts of the studied reservoir.ORIGINALITY/VALUE: The presented research is a new application of artificial neural networks in security in restricted waters. The results obtained in the study may be beneficial for the maritime administration, which is responsible for the safety of navigation in the studied water area. The model can be used to design a survivor's route or a contamination route.This research outcome has been achieved under research projects No 1/S/INM/18 and 1/S/IMFiCH/21 financed with a subsidy from the Ministry of Science and Higher Education for statutory activities.peer-reviewe

Optimization of Design and Technology of Injector Nozzles in Terms of Minimizing Energy Losses on Friction in Compression Ignition Engines

The operation of injection apparatus in self-ignition engines results from the design, manufacturing technology and wear and tear during operation. The technical state of the injector apparatus significantly affects the engine performance, fuel consumption, toxicity and smoke opacity of outlet gases. The most unreliable element of the injection apparatus is the injector nozzle, the quality of which depends on the quality of construction and production, operating conditions and the of the fuels used, etc. One of the design parameters of the injector nozzles, determining the technical state is the geometry of the nozzle holes. An attempt was made to optimize the selection of the dimensions and surface condition of the spray holes to significantly affect the flow properties of the injector nozzles and, consequently, to decide on the size and form of fuel dosed streams to individual cylinders of a self-ignition engine and the quality of fuel atomization. In work, a simulation model was developed, and the pressure losses and the mass fluid of the injected fuel were minimized for selected significant geometric features, taking into account the influence of operating conditions. With the use of Mathematica software, simulation optimization methods and methods based on evolutionary algorithms were elaborated

Analysis of wind and drifter movement parameters in terms of navigation safety : the example of Szczecin lagoon

Purpose: The article presents a comparative analysis of the drift movement in the water area of Szczecin Lagoon (southern Baltic, Poland) and wind parameters in the examined region for the dry summer season. Design/Methodology/Approach: Experimental tests were conducted to determine the relationship between the drifter movement parameters and wind parameters in Szczecin Lagoon area. A set of surface drifters was designed for the experimental study at the Maritime University of Szczecin. Drifters were custom-made to track surface currents. In situ experiments were performed from the end of June till mid-October 2018. Statistical analysis of directional and linear data allowed to link the directions and speeds of moving drifters with wind parameters recorded in two places, Świnoujscie and Trzebież. Findings: As a result of the conducted research, it was ascertained that the direction and speed of air masses flow are parameters that strongly affect the movement of surface waters of Szczecin Lagoon. A significant correlation was found between the wind direction and the drift direction. The coefficient of surface drift was also specified to determine the relationship between drift speed and wind speed. Originality/value: The presented research is a complete novelty in the area of the Szczecin Lagoon. The results obtained in the study may be beneficial for the maritime administration, which is responsible for the safety of navigation in the studied water area. The analysis can be used for projecting the track of pollutants in water.peer-reviewe

Comparative analysis of meteorological conditions on the shores of Szczecin Lagoon

The definition of dynamic areas of searching for shipwrecks, and/or the movement of pollution across waters of Szczecin Lagoon first requires the knowledge and specification of hydro-meteorological conditions across the area. This article compares wind parameters from various sources of meteorological stations located close to Szczecin Lagoon. The wind speed and direction were obtained from Ueckermuende, I Brama Torowa (Urząd Morski Szczecin), and Kopice (wind meter of Szczecin Maritime Academy). Wind direction data analysis was based on directional statistics methods and tools

Research into leeways in the regions of the Świnoujście– Szczecin fairway on the Szczecin Lagoon

The paper analyzes the influence of air mass movement on moving (the leeway) surface water in the Świnoujście–Szczecin fairway region on the Szczecin Lagoon. The Szczecin Lagoon includes waters of the Odra River estuary (Poland’s second largest river) and the southern Baltic Sea. To calculate the leeway parameters, a relevant surface drifter was outlined and constructed. The data on the leeway of the drifter was obtained from in-situ experiments conducted on the Szczecin Lagoon in the summer of 2018. In turn, the air mass movement data was recorded at meteorological stations in Trzebież and Świnoujście. A statistical analysis of the leeway parameters of the drifter was also presented. Distributions of the leeway and wind speeds in the Świnoujście–Szczecin fairway regions were established. Moreover, linear regressions between the leeway and wind parameters were performed by decomposing the leeway into its downwind and crosswind components for each 10-minute sample. It is worth highlighting that relationships between these components of the leeway and wind parameters were studied for weak, medium, and stronger winds. This research may be useful for increasing navigation safety in the Świnoujście–Szczecin fairway regions on the Szczecin Lagoon