This paper presents the reliability assessment results for electromechanical modules, including carbon fiber reinforced composite with thermoplastic matrix, aluminium alloy, and steel housing, through the analysis of competing risks, establishing an association among reliability indicators and non-stationary failure flow using the Weibull probability density function. It has been demonstrated that the estimated probabilities of reliability operations and failure are merely approximations and may deviate from the actual values. This analysis correlates with the estimation of mutual competing risks in the operation of planetary gearbox housing constructed from composite materials. It has been confirmed that the estimated probability of failures is asymptotically effective. A comparative analysis illustrates reliance on simulation methods for planetary gearbox housing made of carbon fiber reinforced composite with a thermoplastic matrix, aluminium alloy, and steel, focusing on parameters such as von Mises stress and deformation (deflection). It has been proven that the electromechanical module, including carbon fiber reinforced composite with thermoplastic matrix, aluminium alloy, and steel planetary gearbox housing is the most reliable, with the lowest heat transfer coefficient, but with the lowest strength.

We demonstrate color shifting from the yellow to the red in the electroluminescence from (ZnGa)S:Mn films. We observe threshold voltages down to about 35 V, extremely low for such devices. We discuss the materials characteristics of the phosphor films, and the potential for improvement of the luminous intensity of the devices.

The study employs X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and metallographic analysis to assess the phase composition and microstructural features of anodic and chrome coatings. In response to increasing demands for enhanced durability and corrosion resistance in defence applications, surface treatments have become an integral part of the barrel manufacturing process. Aluminium barrels were anodised, while steel barrels were hard chrome plated. The electrochemical rifling (ECR) process was conducted under optimised conditions: current ≈ 950 A, voltage ≈ 7 V, pressure ≈ 2.2 MPa and duration ≈ 176 s. Before coating deposition, the inner bore surface roughness was controlled at Ra = 0.8 µm, ensuring reliable adhesion of the subsequent layers. The XRD and EDS results confirmed near-stoichiometric compositions for both coating types. The anodised layers revealed aluminium and γ-Al2O3 phases, accompanied by minor intermetallic compounds, such as S (Al2CuMg), T (Al2Mg3Zn3) and η (MgZn2). Chrome-plated steel sample exhibited the presence of elemental chromium and goethite (β-FeOOH). These findings support the suitability of the ECR method as a foundation for high-performance coating systems in military applications.

This study presents an analytical–experimental investigation of the mechanical and tribological behaviour of two coating systems applied to deep, internally profiled cylindrical components manufactured via Electrochemical Rifling (ECR): a hard anodised aluminium oxide (AAO) coating on an aluminium alloy and a hard chromium coating on alloy steel. The experimental characterisation includes microhardness measurements, coefficient of friction determination, and controlled sliding wear tests. The results indicate that the chromium coating exhibits approximately 3.2 times higher microhardness and a 16% lower average coefficient of friction compared to the anodised aluminium layer, leading to significantly improved wear resistance.A good agreement is observed between analytical predictions and experimental results. For the steel specimen, values of approximately 26,800 cycles (analytical) and 36,000 cycles (experimental) were obtained, while for the aluminium specimen the corresponding values are approximately 2,050 and 2,012 cycles.Considering the degradation mechanisms typical of hard chromium coatings, a conservative reliability-oriented criterion yields a functional service life of approximately 12,000 cycles for the chromium coating and around 1,000 cycles for the anodised aluminium coating. A Weibull-based reliability analysis (R = 0.95) indicates service lives of approximately 5,200 cycles and 433 cycles, respectively.

This study develops an analytical description of the motion of dilute solid particles in the boundary layer of laminar horizontal flows subjected to weak transverse pulsations. The analysis is formulated for dilute spherical solid particles subjected to transverse velocity pulsations in a laminar boundary-layer flow. A coupled matrix representation of the governing equations is formulated, and closed-form solutions are obtained using Laplace transformation. The analytical expressions capture transient evolution, forced oscillations, resonance effects, and long-term behaviour for particles with different density ratios. Numerical evaluation shows that light particles migrate toward faster regions of the boundary layer and accelerate longitudinally, while heavy particles move toward slower layers and decelerate. Transverse pulsations generate oscillatory trajectories whose amplitude increases near resonance. Impulsive perturbations superimposed on the continuous motion lead to discontinuous transitions consistent with the linear matrix system. The results provide a unified physical interpretation of particle redistribution mechanisms in boundary layers and offer a compact analytical tool for dilute multiphase flow modelling.

This study develops an analytical description of the motion of dilute solid particles in the boundary layer of laminar horizontal flows subjected to weak transverse pulsations. A coupled matrix representation of the governing equations is formulated, and closed-form solutions are obtained using Laplace transformation. The analytical expressions capture transient evolution, forced oscillations, resonance effects, and long-term behaviour for particles with different density ratios. Numerical evaluation shows that light particles migrate toward faster regions of the boundary layer and accelerate longitudinally, while heavy particles move toward slower layers and decelerate. Transverse pulsations generate oscillatory trajectories whose amplitude increases near resonance. Impulsive perturbations superimposed on the continuous motion lead to discontinuous transitions consistent with the linear matrix system. The results provide a unified physical interpretation of particle redistribution mechanisms in boundary layers and offer a compact analytical tool for dilute multiphase flow modelling.