The article discusses electrically conductive filaments for FDM printing and, more specifically, the influence of printing parameters on the resulting conductivity of the component. First, the methodology of sample measurements is described. Then, a comparison of samples with 9 different printing parameters is made. Finally, three samples are selected for a detailed investigation of the influence of the printing parameters on the resulting electrical resistivity.
This paper presents a methodology for detecting excitation capacitor faults in self-excited induction generators (SEIGs) used in wind energy systems operating in isolated or rural areas. The proposed approach combines frequency and phase tracking with zero-crossing time rate analysis for real-time anomaly detection. The SEIG is modelled using the finite element method (FEM) to simulate its electromechanical behaviour under various fault conditions. Fault scenarios are introduced by progressively disconnecting excitation capacitors connected in parallel and series, thus simulating failures ranging from one to five units. Monitoring zero-crossing intervals and phase variations enables accurate fault detection without relying on computationally intensive spectral techniques. The results confirm the effectiveness of the proposed methodology in identifying fault-induced distortions and improving the reliability of SEIG-based wind energy systems.
The wastewater generated during showering represents a potential source of low-grade thermal energy that can be utilised to reduce the energy required for domestic water heating. This paper presents an experimental investigation of a shower wastewater heat recovery system in laboratory conditions. Measurements were carried out during summer and autumn periods under operating modes with and without heat recovery for 6- and 10-minute showering cycles. Temperatures and flow rates of the hot water, cold water, preheated cold water, mixed water, and wastewater were monitored. The results showed that the temperature of the cold water flowing through the heat exchanger increased by approximately 6–6.5 K. The experimentally determined heat exchanger efficiency reached 38–39 %, while the relative heat savings were approximately 23 %. The measurements also confirmed the effect of real operating conditions, particularly ambient temperature and non-insulated pipelines, on the measured parameters.
This article extends established methods for determining dosimetric quantities characterising monitored photon fields and for estimating the superficial activity of 137Cs and the concentrations of K, U, and Th in the soil surface layer from spectra acquired during in-situ environmental monitoring on the ground or using unmanned aerial systems (UASs). These methods are based on the response matrices of scintillation detection systems simulated using the Monte Carlo method and on the unfolding technique. This work implements these methods in a unified Python-based workflow for ground-based and UAS-borne scintillation spectrometry, with device-specific response matrices and response functions that directly account for soil water content and height above the ground. The software is complemented by newly established reference sites for unmanned aerial radiometric surveys. Together, they provide the infrastructure for testing and further development of the full acquisition-to-evaluation chain.
A key part in optimising the performance of fibre-reinforced concrete (FRC) lies in ensuring the correct orientation of fibres, especially in structural components where directional stress resistance is critical, such as beams and slabs. However, assessing the orientation of fibres in hardened concrete poses a significant challenge. This study explores the use of the non-destructive evaluation of fibre orientation within FRC by measuring a quality factor (Q-factor) of an electrical coil with an inserted FRC specimen. Through numerical simulations, the effectiveness of the Q-factor measurements were evaluated using several scenarios of fibre positions, quantity, and orientations. It was discovered that the Q-factor is sensitive to these variables and, therefore, it is a suitable tool for material diagnostics.
