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