International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Given are the results of a comparative design analysis of the operating cycle and thermal stressed state of a piston in diesel engine 2F10,5/12 under rated power conditions. To reduce the thermoelastic stresses in the piston, the paper suggests using the modern method of managing the operating cycle – homogeneous mixing and combustion. Such an operating cycle reduces the maximum local temperature in the combustion chamber and the temperature gradients, thereby reducing the thermal load on the piston.

This paper discusses a heat pump subsystem within an existing high-temperature DH system located at a railway station in Omsk, Russia. The goal is to increase the efficiency of an existing high-temperature DH system by describing decentralized heat generation from an environmental point of view. We obtain a balance method whereby the heat loss (or the thermal energy loss) is expressed dependent on the supply and return temperatures so as to reduce operating costs of heat supply. The outcome of calculating the heat loss by this method is a relation that is valid typically for all DH networks. Findings beneath show that switching to a low-temperature DH can decrease operating costs and increase overall heat production efficiency. The reason for the latter is a known logarithmic heat flux-temperature correlation. This paper concludes that the idea of decentralized generation has a great potential for the future, as the implementation of this concept is closely related to a low-temperature DH.

Fish like many living organisms have specific tolerant range of various environmental parameters, thus fish farming of specific types of fish species requires certain conditions that have to be reached. Moreover, the people that work in the fish farming ponds have to be engaged in all day activities to maintain the living fish habitat. Therefore, monitoring and taking actions to maintain the habitat’s sustainable environment for certain fish species inside of fishing ponds over distributed machine to machine communication, which will shorten the time needed for some basic actions, is the main motivation for this paper. In this paper we present an upgrade on a functional Internet of Things (IoT) system for monitoring fish farming ponds. The IoT system consists of various sensors that measure important factors of the water quality like temperature, light intensity or water level, as well as small board computer that processes the data and sends sound and visual notifications to the fish farming manager. The current system lacks the ability to process the data to the end-user via web or mobile platform. Due to remote distance of the fish farming ponds and their location dependence of clean fresh water, one solution of this problem is using expansion module like Wivity modem to enable the end users in real time to monitor and control certain aspects of the fish farming pond IoT system. Wivity modem allows user to communicate to the IoT system via WiFi connection, cellular, LoRaWAN or satellite communication; all in one product. Later on, this module can be integrated with IoT platforms including Japser, Microsoft Azure or Amazon Web Services. For future work, we plan to expand not only the applicable services on different platforms, but also add more control modules and sensors to the existing IoT system for specific fish species.

Horseradish peroxidase represents one of the most exploited enzymes in the process of enzymatic phenol removal from aqueous solutions. It has a catalytic ability over a broad pH range, temperature and contaminant concentration. In this study we have investigated the influence of pH and temperature on process of phenol removal by crude horseradish peroxidase from aqueous solution. Reaction was performed in the presence of low molecular polyethylene glycol (PEG 300) at different temperatures (4, 12, 17, 20, 25, 30, 35, 40 and 45 °C) and pH values (3, 4, 5, 6, 7, 8 and 9). Reaction was monitored by measuring of absorbance changes of the samples taken at certain time intervals from reaction mixture. Obtained results shown that phenol removal from aqueous solution increases by temperature increase up to 35 °C, after which this effect no longer exists. Also, phenol removal increases in the pH range of 3 – 7, while a further increase of pH value leads to the opposite effect. Based on this it can be concluded that phenol removal from aqueous solutions greatly depends of peroxidase activity, because this temperature and pH values represents the optimum values of peroxidase enzymatic activity.

Nano fluids is advantageous with high thermodynamic properties compared to pure fluids. In the last half century, rapid developments in production technology, which allows high-precision production of the micro heat exchangers and the use of the micro heat exchangers in different areas. These developments point researchers to enhance new methods in improving the heat transfer. One of these methods is; to improve fluid’s heat transfer by adding different particulates to the fluid. The nano fluids are the new type of heat transfer fluids that are made by adding nano particulates which has high thermal conductivity to a conventional fluid. Since the solid metal has a higher thermal conductivity than the basis fluid, the addition of the metallic particulates to the fluid increases the heat transfer of the mixture. In this study, for analyzing the temperature performance of fluids with Nano particulates; an experimental study was performed using water to determine the optimum mini channel length and mini channel diameter. Performance parameters are; channel length, tube mini channel diameter, the flow and the inlet temperature. According to the experimental results, the maximum temperature performance of the mini channel was found to be at L/D=250/3 (at Selcuk University condition). Therefore, with these results, the optimum mini channel length and mini channel diameter are determined for the high efficiency that is to be achieved by using nano fluids

The key issue to an automotive engine’s reliability and its durability is the quality of the lubrication system. The primary task of the lubrication system is to provide a continuous supply of filtered oil between two sliding surfaces. By using adequate lubrication oils will reducing friction between moving mechanical parts. Rheological characteristics of lubricating oil directly caused the friction losses due to internal engines mechanisms (piston group, valve train, fuel pump, crankshaft, bearings and seals, etc.). The main components of lubrication system has a poor lubrication during cold start up process of an IC diesel engine and thus is necessary a proper lubricating oil to full fit the complex demands of all engine components and subassemblies. The aim of this paper is experimental investigating of the influence for different classes lubricating oils characteristics and oil filters which are present in market of Republic of Kosovo, especially those with lower prices on engine oil pressure, temperature and flow during start up until the oil warms up some. The obtained results are taken from measuring device which is installed into Fiat passenger car with Spark Ignition Engine for different working regimes.

Measurements of linear thermal expansion coefficient (TEC) of a nanoporous metal carbide based carbon material were car-ried out. The values of linear thermal expansion coefficient in the range from 20°C to 300°C were obtained. The measured value of TEC are presented for this material for the first time.