Archives
-
No. 132 (2024)
The current issue of the Scientific Journal of Gdynia Maritime University features papers spanning diverse topics from the fields of technology and engineering. The papers present research results relevant to automation engineering, electronic and electrical engineering, mechanical engineering, as well as production management.
The paper “Effect of Voltage Fluctuations on Induction Motor Currents” focuses on voltage interference, one of the power quality disturbances found in electrical power systems. Cyclic voltage fluctuations are related to each other by the presence of subharmonics and interharmonics, which are components with frequencies lower than the fundamental frequency or not an integral multiple of the fundamental frequency. Preliminary research is presented related to a four-pole squirrel-cage induction motor with a rated power of 4 kW under voltage fluctuations with a frequency greater than that of the supply voltage. It was found that for the tested motor using symmetrical rectangular modulation with a frequency in the range of 60 to 90 Hz, the current interharmonics corresponding to the subsequent harmonics of the modulating function were significantly smaller than the current subharmonics and interharmonics corresponding to the first harmonic of the modulating function. For the modulation of interest in this work, the frequency of the torque pulse components, corresponding to the individual current subharmonics and interharmonics, was higher than the natural frequency of the rigid-body torsional vibration. Consequently, there was virtually no risk of rigid-body torsional vibration.
Power system lines are used not only for the transmission of electrical power, but also to carry a communication signal, known as ‘mains communication voltage’. Considering electrical power quality, mains voltage should be considered as interharmonics – frequency components that are not multiples of the total fundamental frequency. These components have a detrimental effect on various energy consumers, including rotating machinery. The paper “Effect of Mains Communication Voltage on Induction Motor” is an investigation into the effect of interharmonic frequency components of an electric current on electromagnetic torque pulsation for a four-pole squirrel cage induction motor with a rated power of 3 kW. The results show that, for the interharmonic frequency range corresponding to the mains communication voltage, the moment of inertia of the driven unit has a relatively small or even negligible effect on the current interharmonics and torque pulsations of the motor. The authors suppose that it is probably due to the strong damping of speed fluctuations by the motor's moment of inertia for the interharmonic frequency range considered.
The paper “Application of the Vivaldi Antenna in a Linear Antenna Array for Radar Systems” presents a novel design for a broadband TSA antenna with an expanding aperture to be the primary radiating element in a multi-component antenna design. The proposed TSA antenna has a bandwidth of 0.87 [GHz] (2.35 to 3.22 GHz) at SWR < 2 and 0.55 [GHz] (2.50 to 3.05 GHz) at SWR < 1.3. Based on the tests carried out, the author’s concluded that the input resistance is stable over the entire operating range and close to 50 Ω. The design of the TSA antenna supplied via a half-wave loop was proven to be a far superior solution to the model of the same antenna supplied via a half-wave dipole, as evidenced by the results acquired from the SWR and radiation pattern measurements.
3D printing, also known as additive printing or additive manufacturing, has become part of today’s manufacturing technologies, enabling the rapid fabrication of three-dimensional items from a variety of materials, and thus facilitating rapid prototyping and personalisation of products. In “Effect of Temperature and Printing Angle in FDM Additive Printing on the Strength Properties of PET-G”, the authors undertook to evaluate the effects of selected 3D printing parameters on the strength properties of glycol-modified polyethylene terephthalate. The highest tensile strength was achieved by the specimens printed at an angle of 90o and 230oC. The temperature and printing angle were found to have no significant effect on strain.
The paper “Analyzing the Implementation Process for the Kaizen Method on the Example of ZSP „LUBIANA” S.A.” describes how Kaizen was implemented between 2018 and 2022 at ZSP „LUBIANA” S.A. The outcome of the process completed at ZSP „LUBIANA” demonstrated major significant benefits from improvement of the production process and better commitment of the company’s personnel. The procedures discussed in the paper included aspects related to monitoring and evaluating the effectiveness of the solutions applied, which is an important part of maintenance and continuous development of the site’s Lean Management System.
Robert Starosta
-
No. 131 (2024)
The problems related to advancements in signal processing, mathematical tools and new analysis methods applied in investigations into different industrial fields have been intensively explored over the last few years. In the Scientific Journal of Gdynia Maritime University, this issue is addressed to widely-treated problems occurring in newly-defined disciplines of science: automation, electronics, electrical engineering and space technology. The issue comprises five research papers, specifically dedicated to a subject as a stochastic Petri net-based model of non-enzymatic RNA degradation (1), the speed variation of a cage induction motor under square voltage modulation (2), the effect of rectangular voltage fluctuations on currents in a single-phase induction motor (3), characteristics of the sorption properties of dried hemp (4), and colossus from algebron – gamification used as a tool to engage students in learning mathematics (5).
Paper 1 involves the building and analysis of a stochastic Petri net-based model of spontaneous (non-enzymatic) RNA degradation. The model is analyzed using t-invariants, MCT sets, and simulation-based analyses. The systems approach enables a thorough analysis of the phenomenon, resulting in significant biological insights.
Paper 2 deals with the effect of the square voltage modulation on the rotational speed of an induction motor. The results of the FEM computations are presented for a cage induction motor with a 3 kW rated power and various parameters describing the voltage modulation.
Paper 3 discusses the impact of voltage fluctuations on currents of a single-phase induction motor. The results of the research into currents are presented for rectangular amplitude modulation and are compared with the investigation results under sinusoidal modulation and the appearance of a single voltage subharmonic.
Paper 4 is aimed to assess the sorption properties of dried hemp (Cannabis sativa L.), which determines the storage stability of the raw material. The statistical and desiccator method is used, along with the BET equation to mathematically interpret the course of water vapor sorption isotherms.
The purpose of paper 5 is to discuss various aspects of engaging students in the process of learning mathematics by the gamification of linear algebra, where gamification is used as a tool that allows for high engagement in performing tasks that have been previously considered difficult or uninteresting.
Janusz Mindykowski
-
No. 130 (2024)
This issue of the GMU Scientific Journal features papers concerning very diverse topics in the domain of management and quality. These can be categorised into three topical blocks: transport management, food and consumer behaviour on the food markets, as well as cosmetic products and the properties of the plant raw materials used in the manufacture of these products.
The first paper was devoted to the current issue of inflation, a matter of importance to society and the economy that affects many societies around the world. Its authors demonstrated a relationship between the export of goods and inflation, while hinting at an inversely proportional dependency between these two variables. It was found that inflation is primarily caused by its own values from the past, whereas the export of goods effectively inhibits inflation.
The next topical block concerns food. The first paper on the topic discusses the importance of the thermal processing of selected fish species on their nutritional value and quality. It was demonstrated that the effect behind the importance depends on the fish species, while the overall best method deemed to provide a meal of good quality is grilling. The next paper on food focuses on the analysis of consumer behaviour towards coffee. Its results demonstrate changes in consumer preferences, with the retention of the drivers determining the choice of coffee products.
The third topical block features three papers which concern the application of various plant-based products in the production of cosmetics. The subject follows the current market and consumer trends of zero waste, sustainability, agerexia, and innovation, which are symptomatic of the topicality and materiality of the research discussed in the works. The authors demonstrated that various domestic materials can be used to manufacture cosmetic products, including those initial materials that are considered consumer waste from other products.
All the papers provide interesting data concerning current issues that can be used for strategic planning of businesses and other market actors, while remaining important in the evolution of management and quality.
Agnieszka Rybowska
-
No. 129 (2024)
The current issue of the Scientific Journal of Gdynia Maritime University refers to a variety of topics, from issues related to satellite navigation systems for accurate ship positioning through automatic control systems for pump operation, and the mechanical properties of polyester-glass composites to marketing communication.
The first paper deals with the problem of alternative methods of ship positioning in the open sea compared to commonly used Global Navigational Satellite Systems (GNSS). Despite the advantages of GNSS, the author indicates the need to consider an emergency GNSS backup, in order to assure safe and reliable navigation at sea. For this purpose, celestial navigation is proposed as a cost-effective and readily available backup method for obtaining position information. This problem arises in the current political situation as various factors can jam, disrupt or spoof GNSS signals.
The paper entitled Assessment of the operation of the pump control system using the PID controller presents the results and analysis of a project whose aim was to design, build and programme the automatic system to control the operation of the pump. One of the goals of the project, financed by Ministry of Science and Higher Education, was to enable flow measurement and ensure its efficiency to be smoothly regulated. In order to control the flow and maintain the set flow value, the PID controller has been used various setup configurations. Both the project and article also present an assessment of the operation of the proposed control system.
An analysis of the influence of aluminum powder on the mechanical properties and strength parameters of polyester-glass composites is presented in the next article. The authors present an analysis of the results obtained during a static tensile test and a hardness test. The research has shown that modifying the mechanical and strength properties of composite materials, using an aluminum filler, makes it possible to obtain materials with variable parameters. The authors conclude that the addition of aluminum powder to the composite matrix reduces the tensile strength of the composites but slightly increases their hardness, which can be used to make various types of coatings and structural elements harder.
The last paper describes and analyses the results of surveys and observations in shopping centres regarding customer opinions on sensory marketing activities.
The aim of sensory marketing is to influence the customer's senses and, as a result, evoke associations with a specific product or brand. The research shows that young customers often have knowledge about sensory marketing but do not notice its impact while shopping. As the authors indicate, in order to make the customer feel attached to the brand, it is necessary to adopt a new approach to sensory marketing activities and carefully select stimuli for the target group of potential customers.Agnieszka Blokus-Dziula
-
No. 128 (2023)
The current issue of the Scientific Journal of Gdynia Maritime University contains publications on various topics, covering issues related to the field of engineering and technical sciences and the scientific discipline of mechanical engineering.
The article entitled “The impact of the addition of effective microorganisms on selected parameters of engine oil” suggested increasing the application time forlubricants used in piston combustion engines by adding dedicated microorganisms. This could potentially help reduce the amount of biocides added to engine oils and potentially extend the period between oil changes.
The author assessed the impact of intentionally introduced microbiological additives on the following properties of lubricating oil: kinematic viscosity, dynamic viscosity and density.
The aim of the article entitled “The influence of the burnishing process on the hardness and surface roughness of aluminum welded joints” was to assess the impact of the burnishing treatment on the quality of the surface layer of butt weld faces used to connect individual segments of pipelines. The pipes were made of the EN AW-6060 aluminum alloy. Method 141 (TIG) was chosen to join the segments. Parameters of the surface layer, such as roughness and hardness, were analysed.
The article entitled “Kinematic and dynamic modelling of nonholonomic mobile robots” presents the important and current problem of modelling the kinematics and dynamics of mobile robots. The usefulness of the mathematical model applied, Jacobian and Lagrange equations of the second kind, for designing the drive and actuator systems of a wheeled mobile robot was assessed. Computer simulations were performed using the Matlab/Simulink computer program.
The authors of the study entitled “Influence of added water mass on ship structure vibration parameters in virtual and real conditions” presented a method for assessing the impact of water attenuation on the natural frequency values of structural elements of the hull and superstructure of marine floating objects.
Both model tests using the finite element method and empirical experiments were performed. By comparing the results of both research methods, the error value of the mathematical analysis was assessed.
Based on their research, the authors concluded that the selected method of the numerical model – the finite element method on the Patran-Nastran software platform – provided relatively accurate calculation results with acceptable errors. The proposed calculation method may be applied in practice during the initial design of marine structures.
The issue discussed in the publication entitled “Evaluation of the process of condensation of water vapour in the presence of deposits using a single pipe in the heat exchanger of a condensing power plant as an example” is, according to the reviewers, important in the context of the use of power units and also for the design of micro- and low-power steam power plants offered for the distributed energy sector. The material material is based on the results of experimental research. It has been shown that the relative loss of the mass flow of water vapour condensing on a pipe covered with deposits with a determined value of thermal resistance of 1.9*10-5 m2K/W ranges from 5% to 11%.
The last paper examines the dynamic characteristics of energy flows in electricity, heat, and gas sectors, focusing on the H2 microgrid's role in supplying heat and gas alongside electricity. The paper also analyzes the behavior and impact on grid stability of batteries, power electronics, and electrical loads in the microgrid, and compares overall efficiencies in coupling electric power and gas sectors through electrolysis and fuel cells.
Robert Starosta
-
No. 127 (2023)
The problems related to advancements in signal processing, mathematical tools and new analysis methods applied in investigations into different industrial fields have been intensively explored over the last few years. In the Scientific Journal of Gdynia Maritime University, this issue is addressed to widely-treated problems occurring in a newly-defined discipline of science: automation, electronic, electrical engineering and space technology. The issue comprises six research papers, specifically dedicated to a subject as a mobile application using Augmented Reality (AR) (1), reconstructing damaged data in telecommunication systems (2), authenticated Wifi-based wireless data transmission from multiple sensors (3), improved performance of Wifi-based communication with multiple sensors (4), assessment of the accuracy of a virtual multi-channel temperature measuring instrument (5) and decision parameters used in project financing and their implications for offshore wind farm projects (6).
The first paper (1) presents and discusses the operation of mobile application using Augmented Reality (AR) to visualise the electromagnetic (EM) radiation from a horn antenna. The EM radiation visualisation data were obtained through numerical simulation using the CST Studio Suite software.
The second paper (2) contains a review of machine learning based methods for reconstruction of damaged Automatic Identification System (AIS) data as well as inspirations from other telecommunication system for dealing with this kind of
a problem.In the third paper (3), a novel technique to perform authenticated wireless Wifi data transmission from multiple sensors to the control station is discussed.
This control station is based on a laboratory stand for the purpose of analysing the principle of coexistence between wireless technologies dedicated to industrial automation, such as wireless HART, and general purpose technologies, such as Wifi and Bluetooth Low Energy (BLE).The fourth paper (4) is a continuation of the research conducted in (3), in which the importance of coexistence between different wireless technologies in the instrumentation field is discussed. In order to increase the range of wireless communication, the Wifi based ESP-NOW protocol has been presented as an alternative to performing such a task from the perspective of possible future application in maritime engineering.
Papers (5) is dedicated to the problems of theoretical and empirical evaluation of accuracy obtained in a multi-channel temperature measurement system which works with NTC thermistors. Two different methods were used to theoretically estimate this accuracy: Gauss’s method and The Monte Carlo method. The empirical assessment of accuracy is supported by measurement data collected during the calibration procedures for the device developed and the results of verification measurement performed on the working device.
The last paper, (6), is addressed to solving a problem of wind farm project financing. Since a large part of offshore wind farms is financed by debt capital,
it was examined which criteria currently prevail on the market. The main finding is that cover ratios are the most important key figures for the decision-making process and during the term. -
No. 126 (2023)
The current issue of Scientific Journal of Gdynia Maritime University contains articles on very diverse topics, falling within the discipline of Management and Quality Sciences. Most of them concerned issues related to food and nutrition, their safety and trade. One article presents a completely different subject matter and concerns safety during the pandemic.
The first study analyzed awareness and nutritional behaviors of a selected part of Polish society. Factors influencing food selection were studied. Consumers have been shown to have nutritional knowledge but do not apply it in their everyday lives.
The next article presents the results of an intra-EU study on food trade. Particular attention was paid to East European countries and their cooperation with other countries in the area of food import and export.
The third article deals with topics similar to those discussed in the first publication. The authors examined dietary behaviors of adolescents in the context of sustainable development. The focus was on “less-than-healthy” foods. Here, too, inadequate consumer eating behaviors have been shown. Attention was drawn to the need to monitor society and improve mental and physical well-being of consumers.
Article number four dealt with leadership in food safety management systems. It discussed the importance of leadership in maintaining and improving effectiveness of the system and creating a positive food safety culture. Criteria and measures were proposed that can be used to assess leadership and commitment to maintaining and improving the system.
Another article referred to the period of the CoViD-19 pandemic. The study analyzed the safety of protective masks and the number and types of notifications for these products to the EU’s Rapid Exchange of Information System (RAPEX) used to report dangerous non-food products.
The last article concerned the management of the sauerkraut production process. The study presented the pro-health benefits of this product, its impact on health and value especially in the prevention of civilization diseases. The analysis of the production process management was based on the Griffin model, which made it possible to identify points requiring special control in order to ensure high product quality.
All these publications are interesting and the issues raised in them are current and important for the development of the discipline.
Agnieszka Rybowska
-
No. 125 (2023)
The current issue of the Scientific Journal of Gdynia Maritime University contains two post-conference papers presented during the 10th edition of the European STAMP Workshop and Conference (ESWC) and two papers of the Student Special Interest Group of Underwater Research ‘NKBP SeaQuest’ from Gdynia Maritime University. The ESWC Conference was held on September 29–30th 2022 and was organised by the Gdańsk University of Technology and Gdynia Maritime University.
The ESWC focuses on applications and studies related to the Systems-Theoretic Accident Model and Processes (STAMP) and the first two papers of this issue are dedicated to the STAMP and STAMP-based methods and hazard analysis technique.
The first of these manuscripts deals with the topic of automation in container terminals and the development of autonomous systems. As the authors emphasise, increasing automation may cause a number of new hazards to autonomous operations and operational safety. Heikkilä et al. analyse the applicability of the STPA (System-Theoretic Process Analysis) and HAZOP (Hazard and Operability Study) methods for hazard analysis of autonomous systems, in particular a container handling system. They present the advantages and disadvantages of both methods as well as differences in their application.
Similarly, the problem of system safety is addressed in the second paper, by drawing attention to the complexity of software-centric systems. The authors indicate the need to verify, in particular, systems directly related to safety and to analyse risk scenarios in the STPA process. Model checking is used to verify whether the control algorithm sufficiently implements the safety constraint in the process. The benefits of applying model checking to STPA are presented as well.
The last two papers are prepared by the Student Special Interest Group of Underwater Research ‘SeaQuest’. The first of these manuscripts presents risks related to incorrect decompression. It describes the procedure for properly performed decompression and typical accidents caused by non-compliance with the decompression stops.
The last paper describes various methods of obtaining basic diving licenses on the example of CMAS international diving confederations, the SSI diving school system and two American diving associations, PADI and NAUI. The authors compare and provide a tabular summary of the main recreational diving grades according to the analysed institutions. The Student Special Interest Group of Underwater Research ‘SeaQuest’, in cooperation with PC Divers, has been actively involved in research activities, participating in conceptual research and development studies on market analysis for diving recreational certificates.
Agnieszka Blokus-Dziula
-
No. 124 (2022)
The current issue of the Scientific Journal of Gdynia Maritime University contains publications on a variety of subjects, covering issues from several different scientific disciplines, including: mechanical engineering, automation, electronics and electrotechnology, as well as management and quality sciences.
The paper “Comparison of calculating algorithms of logarithmic decrements applied for welded joints assessment” addresses the subject of vibrodiagnostic tests used for assessing the quality of welded joints between dissimilar materials. The authors assessed different algorithms related to the approximation of logarithmic decrement calculations. Based on model studies they conclude that the most advantageous approximation method is a 4th degree polynomial.
The paper “The influence of TIG welding technology on the properties and quality of joints made of dissimilar steels” presents the technology of dissimilar boiler steel welding, as developed by the authors. One welded material was a medium-carbon non-alloy steel (ASTM A106), the other alloy steel (13CrMo 4-5). The materials were joined using method 141 (TIG). The welding process was used to prepare samples, which were then subjected to the following non-destructive tests: visual observation, penetration and radiographic. The tests demonstrated that the resulting weld achieved quality class B.
The publication “Speed variations of cage induction motors under sinusoidal voltage modulation” concerns numerical calculations using the finite element method and assessment of the impact of phase angles on subharmonic and interharmonic components of electric currents on changes in speed of a 3 kW rated power inductive cage motor. The parameters of the model were identified based on the engine structural data and experimental results. The test results should contribute to a better understanding of the phenomena occurring in asynchronous motors affected by power voltage fluctuations, in particular under fluctuation frequencies matching the natural frequency of the torsional free vibrations of the rotating mass.
The paper “High-speed binary-to-residue converter design using 2-bit segmentation of the input word” proposes a new approach to designing fast binary converters, which enable attaining high pipelining speeds at the FA level. This is achieved by segmenting input words into 2-bit segments. The segmentation procedure is described in detail and illustrated with appropriate examples.
The purpose of the study “Examination of authenticity of selected dark chocolates” was to use cocoa shell determination to test the authenticity of dark chocolates available on Polish and other European markets. The experiments demonstrated that all the tested chocolates met the requirements of the Directive of the European Parliament no. 2000/36/CE and contained no more that 5% of cocoa shells. In the authors’ opinion, the information value of chocolate packagings is insufficient. For example, they lack information on the geographical origin of the cocoa grains and the grain variety used to produce the particular chocolate. It was also observed that the colour of the test chocolates did not depend on the fat content.
The authors of the paper “The phenomenon of food waste among consumers of generations X, Y and Z” conducted a survey study among people from three age groups: aged 60 and over, 31-59, and 18-30. The study concerned the handling of unused food products. It was shown that generational differences differentiate approaches to food wastage. It was found that the low level of knowledge on food waste among the youngest generation translates into their everyday behaviour. Almost half the respondents from this generation (45.5%) throw unconsumed food away. Attempts to use (process) unconsumed food were made primarily by older people.
The paper “The consumer versus innovative dairy products” concerns consumer opinions on dairy products. The study was conducted using the CAWI survey method and an original survey form. The study demonstrated that consumers consume dairy products frequently and consider them an important part of their diets. When buying innovative products, they mainly followed the health impact of those products, positive opinions and attractive prices, while promotion and advertisement were the least important. The survey results led to the conclusion that consumers are open to innovation on the dairy product market, but they have specific expectations towards them in terms of their composition, health benefits, price and packaging.
Robert Starosta -
No. 123 (2022)
The problems related to advancements in signal processing, mathematical tools and new analysis methods applied in investigations into different industrial fields have been intensively explored over the last few years. This issue at the Scientific Journal of Gdynia Maritime University is addressed to widely-treated problems occurring in a newly-defined discipline of science: automation, electronic and electrical engineering. The issue comprises seven research papers, specifically dedicated to a subject as a developed station for receiving satellite signals in the K band (1), the simulation techniques through which a H1 31.25 kbps Foundation Fieldbus Manchester Coded signal can be modulated or demodulated (2), proposals for solving the question of how to calculate the effective value of voltage V if the energy transfer time Δt is less than the period of the function, T (3), the impact of voltage fluctuations in the current of a one-phase induction motor (4), some calculations of the electrical and magnetic field distributions near the high voltage lines (5) and (6), the multi-criteria analysis of selected strategies for energy management in smart home systems (7).
The first paper (1) presents a developed station for receiving signals in the K band, with particular emphasis on the design and alignment of the antenna in the cassegrain system.
The second paper (2) deals with an analysis of the simulation results dedicated to a Manchester coded signal, which describes the mechanisms through which distortion induced by additive white Gaussian noise can be eliminated during the demodulation process, either by using recursive filters such as a Kalman filter or by calculating wave energy levels in specific time intervals.
In the third paper (3), some remarks on the energy transfer analyses during a time less than period T for voltage and current waveforms in electrical circuits are formulated, mainly in the context of how to calculate an effective value for voltage V under the aforementioned conditions in power electronics circuits.
The fourth paper (4) addresses the theme of a single-phase induction motor under voltage fluctuations while the results of empirical investigations are presented for sinusoidal amplitude modulation of various frequencies and are then compared with the effect of voltage subharmonics occurring as single power quality disturbances.Papers (5) and (6) address the specific fields of distribution near high voltage lines adequately: paper (5) concerns the calculations for electrical field distribution and the consequences resulting from that, while paper (6) presents similar issues in relation to magnetic field distribution.
The last paper, (7), is dedicated to the problems of selected strategies for energy management in smart home systems, focusing on multi-criteria analysis as a tool for solving the energy management problem in KNX SMART HOME systems, based on two different strategies applied to two model houses.
This issue of the Scientific Journal of Gdynia Maritime University is dedicated to the memory of our long-time associate, Prof. Marian Pasko from the Silesian University of Technology.
Janusz Mindykowski -
No. 122 (2022)
The latest issue of Scientific Journal GMU contains articles covering a wide range of topics, primarily concerned with Management and Quality Science. The articles present management, engineering and technological research results, focused on service optimisation, food and non-food market innovations, as well as proper product management within the context of food waste. The issue contains publications by Polish authors from various research centres, as well as an article by a faculty member of a Turkish maritime university.
The first article proposes a method of optimising the process of school meal preparation, which may contribute to greatly reducing operating costs and increasing the effectiveness of resource management.
The next article focuses on analysing problems faced by ship operators and sailors during the COVID-19 pandemic.
The remaining articles are concerned with product innovations. The first of these analyses the feasibility of using quinoa as an ingredient in pasta production. It presents the sensory and culinary advantages of quinoa-based pasta, and compares it with regular wheat-based products.
Another article presented in this issue deals with white shrimps. The research results described within indicate that peeling shrimps before storage contributes to reducing their microbiological contamination, which is an argument in favour of this method of storage.
The next article presents the results of an environmental impact assessment of a new polymer-based material at various stages of its life cycle. It was determined that modified synthetic PUR foam with natural fillers has a lower impact on the environment at the production stage in comparison to other types of foam.
The penultimate article focuses on the highly relevant issue of food waste. It presents the theoretical aspects of the problem, as well as the results of an opinion poll analysing the food-related attitudes and behaviours of young people. The respondents proved knowledgeable and rational in their actions, which appears to be the result of the introduction of educational campaigns on food waste in Poland.
The current issue concludes with an article on consumer awareness of the use-by date as well as the terms 'best before' and 'use by'. These were analyzed in terms of whether the knowledge of these concepts influences the handling of food in relation to its type and use-by date.
All articles presented in this issue are interesting, and the issues they address are relevant and important for the development of their respective fields.
Agnieszka Rybowska -
No. 121 (2022)
The current issue of the Scientific Journal of Gdynia Maritime University presents articles on broadly understood transport, including climate-friendly transport, maritime transport, underwater transport, and dematerialisation of bills of lading in the context of maritime transport. The last article of this issue is an exception and relates to economic and quality determinants of Yerba Mate, tea and coffee consumption.
The first paper analyses factors influencing climate-friendly transport and presents a model to explain them and to assess their impact. The authors created a model to identify the relationships between the 21 measured influential factors and four latent constructs: technology, legislative, and socioeconomic factors, and green transportation.
The second paper describes the research project called ‘Batychron’, created as part of the scientific activity conducted by the Student Scientific Underwater Research Society – Sea Quest operating at the Faculty of Navigation of the Gdynia Maritime University. Batychron is a ‘device applicable in hydraulic engineering for underwater transport and diving with the safety of human life’, and the paper presents its construction and application.
The subject of the next paper is the dematerialisation of bills of lading. The paper indicates the need for dematerialisation of bills of lading in maritime transport practice, and the possibility of replacing the paper bills of landing with blockchain bills of landing.
The author of the fifth paper points out the need to identify the aspects that have an impact on the factors determining the safe distances to be maintained between ships in order to find relationships that will be useful for the development of autonomous ships. In the longer term, a study to be presented in the paper will determine the impact of Automatic Identification System (AIS) data on the navigation safety of small autonomous ships.
The last paper characterises Yerba Mate, coffee and tea as products that can be mutual substitutes. The paper presents the economic conditions of production and consumption of these products and a comparison of their stimulant, antioxidant and sensory properties. Moreover, the correlation between the economic and qualitative attributes of their consumption is analysed in the context of their potential as substitutable goods.
Agnieszka Blokus-Dziula
1-25 of 35
Next
