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This issue of the RECENT journal was edited with the support of: ContentsModelling the Tensile Properties of HDPE Composite Materials with Poly (vinyl acetate) Coated Calcium Carbonate Filler
RECENT J. (2022), 67:050-054 https://doi.org/10.31926/RECENT.2022.67.050 Abstract Amorphous calcium carbonate particles with average diameter of 56 µm have been coated with poly (vinyl acetate) to improve their adhesion to a thermoplastic polymer matrix such as high-density polyethylene. The resulting composite materials, obtained by compression moulding of the coated calcium carbonate filler and polyethylene matrix at 140 C present improved tensile strengths, in comparison with the reference material, obtained without poly (vinyl acetate) coating. The mechanical properties of the composite assembly have been modelled with Digimat-FE software, obtaining a satisfactory correlation between the experimental results and the simulated tensile strength. Keywords composite materials, compression moulding, poly (vinyl acetate), mechanical strength Intelligent System for Lighting Control in Smart Buildings
RECENT J. (2022), 67:055-058 https://doi.org/10.31926/RECENT.2022.67.055 Abstract This paper presents an adaptive architecture that centralizes the control of buildings’ lighting and intelligent management to economize lighting and maintain maximum visual comfort in illuminated areas. To carry out this management, the architecture merges various techniques of artificial intelligence. It achieves optimization in terms of both energy consumption and cost by using a modular architecture and is fully adaptable to current lighting systems. The architecture was successfully tested and validated and continues to be in development at Aula building of our university. The author expect this research to extend the study and adaptability of computer technique in design of Smart Buildings. Keywords intelligent systems, smart buildings, light sensors, autonomous control Advantages and Disadvantages of the National Recovery and Resilience Plan
RECENT J. (2022), 67:059-066 https://doi.org/10.31926/RECENT.2022.67.059 Abstract The National Recovery and Resilience Plan (PNRR) is part of the Next Generation EU project, through which the European Union (EU) wants to ensure the economic recovery of the 27 member states, as a reaction to the economic loss suffered following COVID-19 pandemic restrictive measures. The PNRR advantages are that Romania has been allocated almost 30 billion Euros for the period 2021-2026, half grants and half loans. The EU borrows cheaply and gives us the money with the same low interest rate, in plus we get some free money. Romania has an obligation to implement many reforms, to raise quality standards and improve living standards. PNRR is the best thing in Romania's history, as it will develop us as a country far beyond what we were in 1989 when we were the only country in history known with zero debt. Romania has grown a lot economically in the last 30 years and the trend will continue. According to EU standards, the minimum wage must rise to 60% of the average wage, compared to 40% at present. The PNRR disadvantages are that nothing is free, quality costs and hidden defects can occur. In general, cheap things are poor quality and should be avoided. PNRR is too rigid and we will probably not attract all the money allocated. We will have the same prices as in developed countries, and taxes will rise to the same level as theirs. Ordinary people think inflation is high and life is expensive. There will be higher and higher prices and it is not worth keeping money in the bank because interest rates are lower than inflation. Everyone is borrowing, although it is not good to borrow, we have high debts of 49% of GDP and most of the other EU countries have even higher debts. In recent years budget spending has been increasing too much and future generations will pay for the borrowed money. At this rate, if we have debts of over 60% of GDP, we cannot switch to the Euro currency and risk ending up like Greece, which has debts of 200% of GDP. Keywords PNRR, EU, reforms, quality, development Choosing the IR Sealing Equipment of Automotive Wiring Using the ELECTRE Method
RECENT J. (2022), 67:067-073 https://doi.org/10.31926/RECENT.2022.67.067 Abstract For any vehicle the electrical equipment is a basic component, the operation of which has repercussions on consumption, pollution, driving comfort, road safety, etc. Automobile manufacturers pay particular attention to improving the price-quality ratio and customer satisfaction. In this sense, they are constantly concerned with the use of the best performing equipment in the production processes. This paper deals with aspects regarding the sealing operation in the technological process of manufacturing car wiring, the use of IR technology in sealing and the use of the ELECTRE method for the decision regarding the replacement of a sealing equipment, the Minipack TAD oven, with a modern version that uses IR technology. Keywords IR technology, car wiring, ELECTRE method, sealing oven An Implementation of Abrupt Changes Detection and Principal Component Analysis for Monitoring the Thermal Processes in a Cement Rotary Kiln
RECENT J. (2022), 67:074-080 https://doi.org/10.31926/RECENT.2022.67.074 Abstract Rotary kilns for the manufacture of cement, lime and other inorganic binders are widely used in the industry due to their technological advantages: high efficiency, increased reliability, and superior quality of the final product. Modern rotary kilns are equipped with infrared cameras for monitoring the processes inside the kiln, surface infrared scanners for monitoring the temperature at the outer shell of the kiln as well as control systems of all components of the kiln - burner, electric drive, materials supply. The complex chemical, physical, transport and thermal processes that occur inside the cement rotary kilns are stationary processes but space-distributed by sectors along the kiln’s length. The main idea in this article is estimating the length of the sectors where these processes occur. We propose estimating the sectors length by means of the Abrupt Change Detection Algorithm implemented onto the temperature spectra provided by the surface infrared scanner. The results provided by the implementation of this algorithm are the estimated position of the abrupt changes onto the space series of the temperature at the outer shell of the kiln which is correlated with the processes inside the kiln. The analysis of the statistical correlations between the estimations of the locus and length of the processes’ sectors on one side, and the average and the variance of the temperature observations on the other side, allow increasing the accuracy and demonstrating the repeatability of the proposed method. For this purpose, in this article we propose implementing the Principal Component Analysis on the observations of the kiln’s outer shell temperature. Keywords signal processing algorithms, principal component analysis, cement industry, rotary kiln Parallel Operation of Transformers with Different Voltage Ratio
RECENT J. (2022), 67:081-086 https://doi.org/10.31926/RECENT.2022.67.081 Abstract The power transformers can operate in parallel when changing the sources for the consumer supply without interrupting the power supply. The article describes the way transformers with different voltage ratio until 0.5% of the geometric mean of the voltage ratio can operate in parallel without damaging the windings of the transformers due to the equalisation current. There are studied also parallel operation of transformers with different power with power ratio of maximum 1:3 and of the transformers with different impedance voltage with maximum ratio until ±10% of the arithmetic mean and the maximum power limit for each transformer due to his impedance voltage. The possibility for parallel operation of transformer with different voltage ratio was determined through mathematical calculation. In the article is presented an example for parallel operation of two transformers of 25MVA and different voltage ratio 110/20 kV and 110/21 kV. Keywords transformer, parallel operation, impedance voltage, voltage ratio
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