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Mechanical antennas with rotating permanent magnets are a relatively new type of transmitting antenna in low- and ultralow-frequency (LF/ULF) ranges. The perspectives of the applications are encouraging, especially in the field of non-destructive defectoscopy and communications through conductive media (underwater communications), which is reflected in the articles published in the last decade. This article describes the experimental setup, results, harmonic analysis, and simulation validation for two configurations of mechanical antennas with rotating NdFeB permanent magnets. The emphasis is placed on the known analytical equations, specifically on the matching of the measurement results with the analytical data as well as with the results given by the numerical analysis. Also, several means of measurement are used to validate the results through replicate testing. Through analytical analysis and the performed measurement, this article establishes the basics for designing mechanical antennas with rotating permanent magnets for the considered configurations based on a single static magnetic field measurement. Finally, we explore prospects for future research in this domain as well as the advantages and disadvantages compared to other types of LF/ULF antennas. [ABSTRACT FROM AUTHOR]

The bogies of railway cars are important components of the rolling stock system. The test stand solution that we have developed and proposed is used for testing car bogies under load to inspect and highlight the features that ensure operational safety and energy efficiency. This article presents the development and manufacturing of a prototype test stand for railcar bogies, incorporating specific elements such as hydraulic pressure cylinders, force transducers, displacement transducers, a hydraulic pumping system, a data computation and processing system, as well as a control and command unit. The technical topic of developing the test stand is aimed at testing bogies under a controlled, variable and uniformly distributed load, closely simulating the operational conditions of railcar bogies. The accurate and complete determination of the bogie's parameters assures the railroad operator that they are safely interchangeable—Moreover, decreasing the time spent on testing tasks and increasing the testing process efficiency through process automation is leading to a cutback in energy consumption and better predictability of the time intervals required for the repair of railway cars. The prototype consists of three hydraulic pressure cylinders: a centrally located hydraulic cylinder exerting a maximum pressing force of 20 tons-force and two lateral hydraulic cylinders, each applying a maximum pressing force of 10 tons-force. The hydraulic cylinders operate independently from each other, also supporting asymmetric load distributions that recreate the operating conditions as faithfully as possible. The data processing system monitors the magnitudes of the forces and the displacement of the hydraulic cylinders for reporting the specific characteristics of the bogie. To ensure rapid response in the control of the testing process, a control logic unit was developed, entirely dedicated to the control of this technological process. The graphical user interface of the embedded computer system was designed in the LabVIEW programming environment. [ABSTRACT FROM AUTHOR]