Current Issue : January-March Volume : 2026 Issue Number : 1 Articles : 5 Articles
Obtaining electricity from water wave energy using energy converters has a long history, but there are still relatively few commercial devices in the world compared to other solutions using renewable energy. The probable reasons for this state of affairs are operating costs, the cost of minimizing navigation risk for ships, and the geographical and hydro-meteorological specificity of various sea areas, resulting in the use of different, difficult-to-unify solutions. It can be concluded based on a literature analysis that there are no similar commercial solutions in Poland. This article presents the characteristics of waves in the South Baltic Sea near the Polish coast. Calculations of the output power were carried out for a selected type of wave energy converter (point absorber—PA) with different design parameters stimulated by wave energy with variable amplitude and period. These calculations for three characteristic cases are related to a feasibility study of the placement of power point absorbers in the water area around the port of Łeba in Poland. Finally, a short analysis of the results is presented. The obtained calculation results under Polish EEZ conditions are promising because we obtained above 304 KW of energy for 17% of the wave time per year, which seems to be good for local applications....
This paper presents a W-band low-voltage traveling-wave tube (TWT) incorporating a spoof surface plasmon polariton (SSPP) slow-wave structure (SWS) and a dual-sheet beam. The SSPP-based SWS adopts a periodic double-F-groove configuration, which provides strong field localization, increases the interaction impedance, and reduces the phase velocity, thereby enabling a low synchronization voltage. Owing to its symmetric open geometry, the SWS naturally forms a dual-sheet beam tunnel, which enhances the effective beam current without increasing the aperture size. Eigenmode calculations indicate that, within the 92–97 GHz band, the normalized phase velocity is between 0.198 and 0.208, and the interaction impedance exceeds 2.65 Ω. Moreover, an energy-coupling structure was developed to ensure efficient signal transmission. Three-dimensional particle-in-cell (PIC) simulations predict a peak output power of 366.1Wand an electronic efficiency of 6.15% at 95.5 GHz for a 2 × 250 mA dual-sheet beam at 11.9 kV, with stable amplification and without self-oscillation observed. The proposed low-voltage, high-efficiencyW-band TWT offers a manufacturable and easily integrable solution for next-generation millimeterwave systems, supporting high-capacity wireless backhaul, airborne communication, radar imaging, and sensing platforms where compactness and reduced power-supply demands are critical....
The most widely used nanowire channel architecture for creating state-of-the-art highperformance transistors is the nanowire wrap-gate transistor, which offers low power consumption, high carrier mobility, large electrostatic control, and high-speed switching. The frequency-dependent capacitance and conductance measurements of triangular-shaped GaN nanowire wrap-gate transistors are measured in the frequency range of 1 kHz–1 MHz at room temperature to investigate carrier trapping effects in the core and at the surface. The performance of such a low-dimensional device is greatly influenced by its surface traps. With increasing applied frequency, the calculated trap density promptly decreases, from 1.01 × 1013 cm−2 eV−1 at 1 kHz to 8.56 × 1012 cm−2eV−1 at 1 MHz, respectively. The 1/f -noise features show that the noise spectral density rises with applied gate bias and shows 1/f -noise behavior in the accumulation regime. The fabricated device is controlled by 1/f -noise at lower frequencies and 1/f 2-noise at frequencies greater than ~ 0.2 kHz in the surface depletion regime. Further generation–recombination (G-R) is responsible for the 1/f 2-noise characteristics. This process is primarily brought on by electron trapping and detrapping via deep traps situated on the nanowire’s surface depletion regime. When the device works in the deep-subthreshold regime, the cut-off frequency for the 1/f 2-noise characteristics further drops to a lower frequency of 30 Hz–104 Hz....
The performance of wave energy converters (WECs) in terms of energy capture presents considerable challenges in enhancing conversion efficiency. This research proposes a structural design and operational principle for an omnidirectional oscillating buoy WEC (OOBWEC), featuring six absorbers arranged in a circular configuration. To validate the proposed design and operational principle, experimental investigations were conducted within a wave flume. The experimental findings indicate that the capture width ratio (CWR) peaked at approximately 68.15% when the incident wave period was 1.8 s and the wave height was 80 mm. It was observed that as the wave period increased, the CWR initially rose before gradually declining. Conversely, an increase in wave height corresponded with a gradual decrease in the CWR. Notably, due to the angle of the incoming waves, the power captured by the forward absorber significantly exceeded that of the other absorbers. These results provide a basis for future numerical simulations, and further experimental studies will be conducted to optimize the WEC’s structure and improve its energy conversion efficiency....
The development of green technologies in recent years in the field of wind energy conversion into electricity implies a technology transfer from the static switching field to the energy field. This paper presents a wind turbine simulator using a hardware solution following the energy conversion of a real turbine. We implemented this solution for educational and research purposes to train students in the process of electrical conversion in wind turbines. For the simulation, we chose an E82/2300 turbine, installed by ENERCON in a nearby geographical area. The turbine has the capacity to generate 2300 kW of electricity into grids. It has a direct coupling structure of the propeller to the generator. The solution is implemented on a multi-processor architecture with analog signal processing. The structure of a wind turbine is divided into three consecutive blocks, namely TUGEN, DCDC4X, and SIN3F. Each block of the simulator is designed with electronic components. The input and output signals of these blocks have similar waveforms to real signals, and their succession is interconditioned by process parameters. The innovation of the proposed solution is provided by software engineering applied to a hardware structure. The ratio between the simulated and real values is 1:60 in order to visualize the signals on a digital oscilloscope, mainly for educational purposes....
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