We propose employing wire electrical discharge machining (WEDM) for shaping thin-walled, multidirectional, carbon fiber reinforced silicon carbide (Cf-SiC) composite parts. Ceramic matrix composite Cf-SiC combines the outstanding mechanical properties of the carbon fiber with oxidation, abrasive wear, corrosion resistance, and high strength at the high temperature of the silicon carbide matrix. The impact of time-related electrical discharge machining parameters (pulse ON-time and break OFF-time) on the material removal rate and surface roughness are analyzed. The material removal rate of the Cf-SiC is proved to be 36% lower than that for machined steel grade 55. The high thermal stresses and interaction of the composite accompanying WEDM are also discussed. Furthermore, an alternative mechanism to the WEDM of metals has been investigated and confirmed by a scanning electron microscopy (SEM) analysis. The morphology of the machined Cf-SiC surface demonstrates the dominance of the carbon fibers’ fracture mechanism, both the transverse and longitudinal forms, with interphase detachment over craters and micro-cracks, pitting, and spalling on the SiC matrix. Satisfactory roughness indicators (Sa = 2 µm) are obtained in 3D topography measurements of the Cf-SiC surfaces. Concluding, the WEDM should be considered a good alternative to Cf-SiC abrasive machining when cutting holes, grooves, keyways, splines, and other complex shapes.

The implementation of construction projects largely determines the development of modern cities. However, such projects impact both urban freight transport and residents. To reduce this impact, increasingly more attention has been paid to the issues of sustainable development. Sustainable urban freight transport has become a priority for European cities. It also contributes to construction supplies. This article presents the results of analyzing construction supplies and the assessment of their compliance with the principles of sustainable development using the example of the city of Szczecin. This allows for the diagnosis of problems in this area, and solutions in the field of sustainable construction are collected. The presented research includes unstructured observation of construction projects in progress, structured interviews with entities implementing construction projects in Szczecin, and additional expert research to identify solutions in the field of sustainable construction supply in cities. This enables the research objective to be achieved and conclusions to be developed.

The presented research shows the possibilities of using chatbot technology in the maritime industry. The authors pay special attention to maritime education, broken down into standard and complementary education. The research is based on the results of a survey, which addresses students of five European maritime universities and examines their opinions about chatbots. Additionally, analogies are applied to the case studies of the successful implementation of chatbots in non-maritime businesses. This research determines the current status and development opportunities of maritime chatbots.

In response to the challenges of environmental protection and the need to be close to nature and to reconnect with it, an unusual motor yacht design is developed with an abstract architectural form modeled on an armadillo. Due to the innovative form of the hull, a specific approach to pre-design is used, with the research objective of verifying that for the organic form of the hull, it would be possible to meet all the design criteria and regulations required for the design of a yacht. This article first characterizes the initial assumptions and then presents the process of determining the main dimensions with simultaneous modification of the hull shape. In order to maintain the basic dimensional proportions, based on the classic motor yacht, the recommended values of design factors are controlled. Moreover, the hydrostatic parameters of the unconventional hull shape are calculated. As a result of preliminary resistance and propulsion analyses, a propulsion system in the form of electric motors is selected, and, to meet emission requirements, the use of photovoltaic panels is additionally proposed. A stability and equilibrium analysis is carried out for one of the load cases and checked with the requirements of the Polish Register of Shipping (PRS) rules. The design of the hull of the yacht, covered in an interesting form of scales, together with the layout of the yacht’s interior, is presented in three-dimensional form, bringing the conceptual idea to life. The result of the design work and analysis is an inspiring hull shape based on nature, complying with the design guidelines and regulations that apply to yacht design.

Nowadays, most content creators focus on distributing rich media at the highest possible resolution. Currently, the majority of sold consoles, media players, computer hardware, as well as displays and TVs are advertised as 4K-compatible. The same trend is observed in the case of popular online streaming services and terrestrial TV broadcasts. Generally speaking, it is assumed that higher bitrates provide higher subjective judgements. In this paper, we present the results of a user experience (UX) evaluation study on the quality of video content coded and transmitted in different resolutions in the internet protocol (IP) environment. The image resolutions include 1K (1920×1080 pixels; full-HD), 2K (2560×1440 pixels; wide-QHD), and 4K (3840×2160 pixels; ultra-HD) content that are processed in the H.265/HEVC (high-efficiency video coding) format. A subjective evaluation is carried out in a laboratory consisting of 20 iMacs with a 21.5-inch 4K Retina (4096×2304 pixels) display. The group of viewers included 28 individuals aged between 21‒35 years old, comprising people with and without visual impairments. The obtained UX results are compared with previous experiments, including both objective quality of service (QoS) and subjective quality of experience (QoE), as well as the impact of downscaling to 1K from 2K and 4K. The outcomes of this study may be of particular interest to any party interested in video content processing and distribution, as well as consumption and storage.

This paper takes the form of a comparative life cycle assessment (LCA) analysis of 40-foot steel and composite containers based on GaBi® software. Reducing greenhouse gas emissions can be undertaken, among other things, by reducing the weight of the container, which is possible if lighter materials with comparable mechanical properties to steel are used. The LCA analysis allowed us to estimate the energy consumed and the amount of greenhouse gases emitted during the production of a steel and composite container. It turned out that the energy consumed in the production of the composite and steel container is practically equal in value, provided that carbon fiber from the polyolefin precursor is used in production. The processes with the highest energy intensity for container production are carbon fiber and COR-TEN A® steel production and processing. Changing the container material from steel to composite would save fuel and greenhouse gas (GHG) emissions into the atmosphere by 5.1 % and 18.3 % for road transportation and sea shipping, respectively.

This article presents selected properties of mixtures produced from two types of fly ashes from one coal-fired power plant. Mixtures made of fly ashes from a conventional boiler without flue gas desulfurization products (10 01 02) and from a fluidized bed boiler with flue gas desulfurization products (10 01 82) are subjected to testing. The mixtures are prepared using mine water. The tested mixtures are characterized by a liquid consistency in terms of flowability in a range from 160 mm to 280 mm. The mixtures made of 10 01 82 ashes show twice as much water demand, shorter setting time, and higher strength than those made of 10 01 02 ashes, but, unfortunately, they have a much higher volume of excess water. Moreover, the mixtures of 10 01 82 ash do not undergo full slaking, in contrast to the mixtures of 10 01 02 ash (conventional boiler). The requirements of the PN-G 11011:1998 standard, relative to the discussed parameters, are met by the mixtures made on the basis of ash 10 01 82 originating from a fluidized bed boiler in terms of flowability of up to 240 mm. This is the ash type useable in sealing technology.

The aim of this article is to identify the best practices to reduce potential risks in passenger transport using the example of urban public transport in Berlin. Due to dynamically progressing urbanization processes and the related development of the German capital, the demand for transport services increases. A significant problem has become the coordinated management of public transport for passengers and ensuring safety in the means of transport and available infrastructure. Local government and public transport managers in Berlin have decided to introduce solutions to reduce potential threats to public transport participants, thereby contributing to improving the quality and safety of the transport services provided. The methods of source analysis, descriptive analysis, and deduction are used to conduct the analysis in this study. The results show that the constant search for new solutions to transport problems is a challenge for city managers in the era of rapidly progressing urbanization processes.

This study explores determinants of organizational support perceptions among employees within container shipping agencies. It examines the influence of leadership styles employed by shipping agency managers on perceived organizational support. Employing correlation and multiple regression analyses, the non-normally distributed data prompts the utilization of the Kruskal-Wallis H test. A survey was administered to 258 employees in 255 shipping agencies from major Turkish shipowner companies dominating the maritime transport sector. A positive correlation is established between perceived organizational support and leadership style dimensions. Additionally, it suggests that efforts to create a supportive environment, especially for junior employees, can mitigate high turnover rates and enhance organizational performance. Practical implications include the recommendation for shipping agencies to focus on leadership development, communication improvement, and skill-building initiatives to foster a supportive workplace environment.

The topic of autonomous vehicles has become popular in recent years, not only because of technological developments but also because of existing challenges in the transportation industry. Autonomization of means of transport has an element of competitive advantage among manufacturers of such vehicles. For their customers ‒ i.e., transport companies ‒ this, in turn, means greater safety, greater driving comfort, and the ability to stay in the market and not fold when such a company runs out of drivers. Over the past few years, we have dealt with such a situation ‒ on the one hand, we have seen a growing trend in the amount of cargo to be transported and, on the other hand, there is a decline in employment in the transport sector (especially cargo). The supply of labor in the industry does not cover the demand for this workforce. The goal of this research is to determine the current state of the cargo transportation sector and to formulate possible advantages and disadvantages of the partial introduction of autonomous vehicles performing cargo transportation as a response to existing threats in the industry

Based on cloud providers’ reports on service outages, it has become clear that how a web service is deployed is of great importance. Clearly, using one service supplier is insufficient because it introduces single points of failure. In this paper, a novel high-availability multi-cloud model intended for a web service is proposed, which is free from such shortcomings yet preserves convenient assets of computing clouds. The methodology used to improve web service availability should involve several cloud suppliers and devise management techniques that control access to them. This is achieved by means of the server availability tracking algorithm, which controls client apps’ access to the service. Moreover, typical benefits and problems involved in choosing IT infrastructure for a web service are elaborated. State-of-the-art cloud computing models, such as IaaS, PaaS, SaaS, BPaaS, and INaaS, are outlined. Operating systems statistics used for web services are included. Open-source monitoring software solutions are gathered, which help administrators to monitor and govern web servers.