：In order to avoid friction and scratching when conveying objects, a squeeze-film levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a ¼ symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results show that the pure flexural and mixed flexural wave shapes with different wave number exist at specific frequencies. The amplitude of the central point of an aluminium plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirm the theoretical results and the feasibility of the prototype, and also confirm that objects can be floated at several resonant frequencies under forced vibration conditions. The system provides the largest levitating capacity when both the piezo-electric disc and the plate resonances coincide.

No abstract

No abstract

During the last four centuries, there have been extensive research activities looking for green and clean sources of energy instead of traditional (fossil) energy in order to reduce the accumulation of gases and environmental pollution. Natural dye-sensitized solar cells (DSSCs) are one of the most promising types of photovoltaic cells for generating clean energy at a low cost. In this study, DSSCs were collected and experimentally tested using four different dyes extracted from Mentha leaves, Helianthus annuus leaves, Fragaria, and a mixture of the above extracts in equal proportions as natural stimuli for Tio2 films. The result show that solar energy was successfully turned into electricity. Additionally, DSSCs based on mixtures of dyes showed better results than those based on single dyes. Efficiency (η) was 0.714%, and the fill factor (FF) was 83.3% for the cell area.

This paper details the process of designing, analysing, manufacturing, and testing an integrated solid-state hydrogen storage system. Analysis is performed to optimise flow distribution and pressure drop through the channels, and experimental investigations compare the effects of profile shape on the overall power output from the fuel cell. The storing of hydrogen is given much attention in the selection of a storage medium, and the effect of a cooling system to reduce the recharging time of the hydrogen storage vessel. The PTFE seal performed excellently, holding pressure over 60 bar, despite requiring changing each time the cell is opened. The assembly of the vessel was simple and straightforward, and there was no indication of pressure damage owing to the FEA analysis that was performed. The cooling chamber, although producing minor leaks due to design oversight, increased performance dramatically, showing a reduction in internal powder temperature from 130 C, down to 25 C during the absorption process, as well as reducing the absorption time down from 30 minutes to just over 5 minutes. The novel idea of implanting a sheathed thermocouple into the centre of the hydride powder proved to be highly valuable asset and provided important information, especially during desorption where the outside container could be heating up, while the inner powder is still cooling down, data that have not been seen before.