Solid State Phenomena Vol. 237

Abstract: In the present paper, the comparison results of two main kinds of the power lines are presented, namely, overhead lines and cable lines. The analysis was done in the low-voltage mains network in the frequencies identified by the CENELEC organization for a narrowband transmission using low-cost PLC modems. The currently data transmission with the use of the PLC technique finds increasing use in the area of the communication for the Smart Grid, especially because of Smart Metering and Smart Lighting systems development. Independently form the implementation of the PLC transmission technique, a process of replacement of overhead lines with cable ones is carried out. Undoubtedly this process must have an influence on the transmission prosperities over the mains network. This paper is aimed to show differences in the secondary transmission parameter of the two main constructional types of low-voltage lines, which have the same electro-power parameter. The influence of these differences on the transmission quality is also discussed. The study has been limited to aluminium and copper wires and was made in the low-voltage mains network.

Abstract: The durability and reliability of electromechanical drives is inseparably linked to the broadly defined environmental conditions under which they operate. The design of new solutions characterised by a high level of safety requires the execution of laboratory tests in accordance with the applicable legal regulations, and with a particular focus on the user requirements, that would simulate the actual environment of application. The aim of the research was to develop a test system for electromechanical drives that can be used in particularly demanding systems, e.g. fire protection or process control systems. The hardware and software solutions applied allow one to determine the characteristics (force, displacement, current, and supply voltage as a function of time) in changeable climatic conditions. As part of the verification of the system, the author studied the prototypes of electromechanical ball-screw actuators developed at the Institute for Sustainable Technologies – National Research Institute (ITeE-PIB) and dedicated for the rail traffic control system.

Abstract: Microcrystalline diamond thin films have been prepared using hot filament CVD technique with a mixture of H₂/ CH₃OH as the reactant gas. We demonstrated that the ratio of H₂ / CH₃OH in the reactant gas and total pressure in reactor chamber plays an important role in control of the grain size of diamonds and the growth of the microcrystalline diamonds. The object of this article is to summarize and discuss relation between structural properties of different diamond layers and technological parameters of their synthesis. The physical properties of the Hot Filament CVD microcrystalline diamond films are analyzed by Scanning Electron Microscopy and Raman spectroscopy. The sample grain size varies from 200 nm to 10 μm and their quality was checked on basis of 1332 cm⁻¹ diamond peak. The ratio of sp³/sp² carbon bonds was determined by 1550 cm⁻¹ G band and 1350 cm^-1 D band in the Raman spectrum

Abstract: Aqueous technological liquids are widely used in industrial processes. However, due to limited resources, there is an increasing pressure on their protection and reduction of water consumption by, for example, closing water circulation. It is facilitated by the development of membrane technology. The article describes a method for regenerating aqueous technological liquids used in metal surface treatment processes and cleaning a production plant. This process was conducted in batch system using a mobile microfiltration installation. The working unit was equipped with tubular ceramic membranes having a nominal pore diameter of 0.2 μm, working in a cross-flow regime. The main advantage of the apparatus is its low weight and high mobility. The installation and method of regeneration were verified during the processing of a model alkaline liquid used for cleaning a plant in the dairy industry. It was found that microfiltration can be used to remove technological impurities (coagulated proteins and fats) from the liquid. The physicochemical properties of the liquid, including alkalinity, remained stable after repeated filtration. This indicates that the purified liquid can circulate in the system and be used in accordance with its original purpose. The proposed solution enables the reduction of water consumption and chemicals used for the preparation of these liquids.

Abstract: Antifreeze glycol-based fluids are widely used in various types of industrial systems, equipped with indirect heat exchange systems. A very broad area of the application of glycol fluids is possible due to their primary physicochemical properties, i.e. relatively high boiling point, very low freezing point, and negligible thermal expansion [1,2]. Examples of the application of these fluids may be, e.g. cooling systems and air conditioning, in which glycol fluid is the heat transferring agent [3 – 5].

Abstract: The pro-ecological production processes in enterprises require minimising the amount of generated waste products, for example, by processing them and recycling. Often, spent plastic lubricants do not meet performance requirements in only some of their properties, and after physiochemical treatment, they can be used in places with lower performance requirements. This article presents a multi-stage method, a device for the purification of used lubricants, and ways to modify the purified products in plastic cold forming. The tests were conducted on a mixture of lubricants after slotted filtration treatment and chemical composition adjustment. The efficiency of lubricant purification was evaluated. Physicochemical and functional properties related to the performance of final products were determined. It was found that, as a result of the applied purification processes and chemical composition modification, the obtained products were characterized by high durability, meeting the requirements of lubricants for cold forming.

Abstract: Microalgae, as a renewable raw material, are gaining wider technical use, due to their rapid growth and high lipid content. Thanks to their ability to produce secondary metabolites that are chemically related to vegetable oils, they can provide an alternative source of organic components of operational liquids. The study investigated the properties of the lubricating oil obtained from algae and compared them with the properties of selected commercial lubricating oils: vegetable, mineral, and synthetic. Antiwear properties were evaluated based on the value of the limiting load of wear (G_oz), and antiseizure properties are based on the value of scuffing load (P_t). The studies were conducted with the use of a four-ball machine. Its test elements were 100Cr6 steel balls and the same balls with low-friction coating (WC/C). Friction tests were carried out in the following material combinations: steel-steel, steel-WC/C, WC/C-steel, and WC/C-WC/C. It was found that in the WC/C-WC/C and WC/C-steel material systems, the algae oil has better antiwear and antiseizure properties than the mineral and vegetable oil. It is therefore appropriate to consider the algae oil as a substitute for commercial oils, particularly the vegetable one for technical applications, e.g. when composing organic lubricating materials intended for the lubrication of friction systems with WC/C coatings.

Abstract: Methane fermentation leads to the formation of biogas in the process of wastewater treatment, but a limitation to its use is the low effectiveness of the removal of phosphorous compounds under anaerobic conditions. The study demonstrates a method to solve this problem through the use of a magneto-active microporous filling, produced by extrusion technology from polyvinyl chloride. This has increased the effectiveness of dairy wastewater treatment by stimulating the selective development of specific groups of microorganisms and the chemical binding of the phosphorous compounds in biological processes as well as chemical sorption on the metal surface of the filling. Regardless of the used organic loading rate, the efficiency of phosphorous removal from the wastewaters was about 85%. Achieving low concentrations of phosphorous in the effluent was directly influenced by the method of the wastewater operation and disposal by magneto-active filling layer.

Abstract: The possibility of the economic utilisation of the glycerine phase and soaps will decide on the profitability of biofuel production technologies. A concept of using waste glycerol fraction, which is a by-product of esterification, as an energy source in a typical solid fuel grate boiler is investigated. Based on studies of the combustion of glycerol fraction in an adapted commercial boiler, it was found that the combustion process of glycerol fraction is very different from the combustion of solid fuels. Established technology for fuel delivery (injection into the combustion chamber) determines the dynamics of the combustion process and the intensity of oxidation, and its effects can be controlled by the characteristics of the injection of glycerol phase. It is possible to use glycerol fraction as an alternative fuel that is neutral for the environment (CO₂ emission factor = 0) in a typical solid fuel grate boiler.

Abstract: The increase in pollution and contamination of the environment in recent years has resulted in the increase of interest in its protection. The basic premise of environmental policy, which is reflected in a number of legal acts, is carrying out activities aimed at minimizing the amount of produced waste [1-3]. In particular, this applies to waste that have harmful effects on the environment, and it includes the vast majority of industrial oils and technological, petroleum-based fluids (over 85%) [4]. One of the fundamental directions related to their use, in accordance with the standards of protection of the environment, is reducing the consumption by extending their functional life [5]. The maximum extension of the functional life for oils and fluids is the goal of the systemic approach to the problem of rational use, which includes the process of the monitoring of key functional properties and systematic, periodical treatment. The most beneficial are on-site treatment processes of oils and fluids conducted while maintaining the continuity of the technological processes. It is preferable to use mobile treatment devices, which provide the means to create a dispersed system in fluid treatment in successive machines and equipment [6-8].