Scientific Journal of Gdynia Maritime University

CURRENTS OF SINGLE-PHASE INDUCTION MOTORS SUPPLIED WITH VOLTAGE CONTAINING INTERHARMONICS

Marcin Pepliński, Piotr Gnaciński — Fri, 26 Sep 2025 00:00:00 +0000

In real power systems, the voltage waveform is not a perfect sine, but contains various additional frequency components, like harmonics, and in some power systems also subharmonics and interharmonics, which are components of a frequency less than the fundamental frequency or not being its integer multiple. This paper deals with the effect of voltage interharmonics on currents of a single-phase induction motor with a permanently connected capacitor. It was found that the current characteristics are different from the analogical ones determined for a 3-phase induction motor.

CURRENTS OF INDUCTION MOTOR UNDER VOLTAGE FLUCTUATIONS

Damian Hallmann, Piotr Gnaciński — Fri, 26 Sep 2025 00:00:00 +0000

Voltage fluctuations are a common occurrence in power systems. They can be regarded as a superposition of the fundamental voltage component, subharmonics and interharmonics – components at frequencies below the fundamental one or not being its integer multiple, respectively. This paper focuses on the effect of the moment of inertia of a driven unit on the subharmonics and interharmonics present in the supply current of a cage induction motor under rectangular voltage modulation. The results of a 2D finite element analysis are presented for a cage induction motor with a rated power of 3 kW.

SUSTAINABLE RECOVERY OF PRECIOUS METALS FROM CHLORIDE SOLUTIONS BY SOLVENT EXTRACTION

Anna Cieszyńska — Fri, 26 Sep 2025 00:00:00 +0000

Solvent extraction in hydrometallurgical processing is a suitable method for precious metals extraction/separation from chloride solutions and therefore proven to be an alternative to the conventional method of separation. This paper presents results of the removal of palladium(II), gold(III) and platinum(IV) ions from chloride media in the extraction-stripping process using trihexyl(tetradecyl)-phosphonium tetrafluoroborate [3C₆C₁₄P]BF₄ as the extractant. The efficiency of extractive separation of the examined metals depends on the acidity of the aqueous solution. The stripping from a loaded organic phase provides effective and quality separation of palladium(II), gold(III) and platinum(IV). The extractant studied ([3C₆C₁₄P]BF₄) can be reused in the next cycles of the extraction-stripping-regeneration process without a significant loss in the extraction power, which is in line with the assumptions of sustainable recycling.

FUTURES LITERACY OF QUALITY AND ITS RELATIONSHIP TO SUSTAINABLE DEVELOPMENT AND MANAGEMENT

Zenon Foltynowicz, Joanna Witczak — Fri, 26 Sep 2025 00:00:00 +0000

Futures literacy is a concept that is gaining importance in today’s dynamically changing world. It is the ability to use the future as a tool to make informed decisions and implement innovations now. According to UNESCO and the European Union, futures literacy is one of the key competences that allows us to be better prepared for different future scenarios. Through this skill, we can better understand and predict changes, which is extremely important in the context of global challenges such as technological development, and climate and social change.

Futures literacy of quality combines the concept of futures literacy with the pursuit of improving quality in various areas of life (from education to industry), and enables a better understanding of future trends and challenges regarding the quality of products, services and processes.

Moreover, nowadays traditional approaches to literacy may prove insufficient in preparing individuals for the complexity and uncertainty of tomorrow. Integrating the principles of sustainable development and quality management in education requires a future-oriented view of literacy. There is therefore a need for a comprehensive understanding of the interdependencies between futures literacy, quality and sustainable development.

Examples of the application of futures literacy in the context of improving sustainability and quality management are presented.

MICROBIOLOGICAL CONTAMINATION MONITORING IN LAUNDRIES – MODERN TRENDS AND BIOLOGICAL CONTAMINATION CONTROL SYSTEMS

Katarzyna Jekiel, Justyna Syguła-Cholewińska — Fri, 26 Sep 2025 00:00:00 +0000

Microorganisms inhabiting textile products during use and originating from the environment or human skin can be a source of microbiological contamination in production, services and household practice. To ensure that the appropriate level of microbiological quality is achieved for textiles used in industries like medical, beauty products/cosmetic and food processing, textiles are processed at commercial laundries, where the effectiveness of the cleaning process is monitored for soil removal and biocidal effectiveness against microorganisms. The RKI guidelines, mandatory for hospital-use textiles, RAL-GZ 992 or a RABC system focused on analysing the risk of microbiological contamination of laundered products at all stages of laundry processing, are helpful in assessing the biological contamination of laundered products.

CIRCULAR ECONOMY IN CRAFT BREWERIES: INNOVATIVE STRATEGIES FOR WASTE REDUCTION AND SUSTAINABLE DEVELOPMENT

Małgorzata Krzywonos, Agnieszka Piekara — Fri, 26 Sep 2025 00:00:00 +0000

The craft brewery industry is growing rapidly but faces sustainability challenges due to waste, water use, and emissions. This study examines circular economy strategies in craft breweries through case studies, focusing on waste reduction, by-product valorisation, and sustainable operations. The findings reveal that repurposing spent grains, using renewable energy, and fostering local partnerships enhance both environmental and economic performance. Policy support and education are crucial for broader adoption. Implementing circular practices not only reduces waste and costs but also strengthens brand reputation and industry resilience, demonstrating the viability of sustainability-driven business models in the craft brewing sector.

FRESH FRUITS SAFETY

Sabka Pashova — Fri, 26 Sep 2025 00:00:00 +0000

The problem of food safety is extremely relevant nowadays due to the general characteristics of the modern world, such as environmental pollution and urbanisation. Foods of plant origin, and in particular fresh fruits (FFs), are contaminated before they are offered to consumers or processed into food products. Fresh fruits are classified as low-risk foods (foods with a low risk of foodborne illnesses), as they have a protective cuticle and epidermis on the surface compared to most vegetables. The aim of this paper is to present and analyse the essence of FF safety, factors affecting FF safety, legislation in the field of fresh fruit safety and the indicators that should be analysed for determination of FF safety according to the regulations and research carried out up to this moment.