The design of a floating, innovative device for river water aeration and conversion of mechanical energy to electrical energy required the analysis of a number of geometrical and dynamic features. Such an analysis may be carried out on the basis of existing methods of numerical fluid mechanics. Models of pressures, forces and torques characteristic for the conversion of watercourse energy were developed for two basic concepts of innovation. These pressures, forces and torques were calculated, designed, and experimentally determined for the variable geometric form and dimensions of the designed working elements of the innovative roller-blade turbine rotor.
This work focuses on the re-use of biopolymer wastes to produce the pipes and reduce the impact of these materials on the environment. The ratios of 10, 20, 30 and 40wt% of recycled polyethylene terephthalate (RPET) were added to the reference blend, which consists of recycled low-density polyethylene (RLDPE) and recycled high-density polyethylene (RHDPE). Rheological and mechanical tests were performed on these blends. The blend of RLDPE and RHDPE was already successful in the manufacturing of pipes. The capillary rheometer was used to check the shear viscosity and shear stress behaviour with the shear rate increasing for different blends. The density, tensile strength, elastic modulus and impact strength were also tested for all blends. The results showed that the shear viscosity decreases and the shear stress increases with the shear rate increasing for all blends. In general, the addition of RPET to the reference blend decreases the viscosity at each shear rate. The blends of ten wt% and 20wt% are more compatible with the reference blend, while the blends of 30wt% and 40wt% exhibit a clear deviation after a shear rate of 300. The density indicates an increase with the increase of RPET to the reference blend. The tensile strength increases and impact strength decreases with the increase of RPET up to 30%. After that, the tensile strength decreases and impact strength increases up to the 40wt% RPET. The results showed that the rheological test can be used to predict the mechanical behaviour. Additionally, there was a good agreement observed between the rheological and mechanical tests. The ten wt% and 20wt% blends were more suitable for this task.
This article’s focuses of photovoltaic installations, which are becoming more and more popular in Poland and around the world. A short theoretical introduction to photovoltaic cells is presented, and the aim of the research is distinguished. Then, the formulas for the parameters characterizing solar cells are derived. The parameters that determine the highest efficiency of solar cells are specified in the next section. In the experimental part, tests of a selected photovoltaic installation were carried out. Based on the research, we conclude that temperature and sunlight have a significant impact on the efficiency of solar cells.
Compared to linear analogs, hyperbranched polymers (HBPs) have gotten much attention in the last decade because of their intrinsic globular topologies and distinctive features like low viscosity, high solubility, and a high degree of functionality. In this work, four types of hyperbranched polyester polymer HBPs have been synthesized using the A2+B3 polycondensation methodology. Firstly, the starting material B3 monomer (Pyrimidine-2,4,6-triol) has been synthesized using urea and malonic acid with the presence of sodium Na as the catalyst for the reaction. Secondly, four types of materials (tartaric acid TA, adipic acid AD, maleic acid MA, and phthalic anhydride PA) as A2 monomers were added to the starting material B3 monomer in an oil bath to prepare the four types of HBP. The chemical structure of HBPs was characterized by FTIR, and 1H-NMR. The molecular weight of the prepared HBPs was characterized by gel permeation chromatography GPC, and thermal properties were characterized by differential scanning calorimetry DSC and thermal gravimetric analysis TGA. FTIR results showed that there are new bands, such as C-O-C between A2 and B3 monomers, as indicated by 1H-NMR. In addition, GPC shows that the prepared polymers have a narrow molecular weight distribution with good thermal stability, as indicated by DSC and TGA.
This work is a Copper oxide (CuO) thin films were effectively produced using cold spray technique. The process take place in an inert gas (helium) without using catalyst. Nano CuO was deposited on a glass slide, using helium as carrier gas heated to 100, 200, 300, and 400 °C, respectively on heated glass substrates at 300°C. The effect of structural and electrical properties was examined at each temperature for each film. AFM images show that the CuO thin film have different diameters ranging from 80 to 600 nm, and low surface roughness about 20.9 nm. The measured value of copper oxide resistivity was found to be decrease very much with the increasing temperature. All the result showed that copper oxide is suitable material for photovoltaic applications. This research is part of a larger work for the solar cells industry. Therefore, the aim of this research is to study the electrical properties of solar cells in the primary stages of manufacturing from available materials at low costs.
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