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Power engineering is facing major changes - some of them are captured by the smart grids newly adopted paradigm, while others are perceived as external impact of technological evolution in the traditional topics, like measurements. Here the innovation is usually reduced to smart metering initiatives. However, measurement technology is acknowledged as being a fundamental layer in the endeavor of setting...
Because current regulations stimulate engine downsizing, achieving high performances with a small displacement engine is very difficult, keeping in the same time the level of emissions and fuel consumption as low as possible. This article aims to provide a solution for these challenges, combining a small displacement turbocharged Diesel engine with an Axial Flux Permanent Magnet (AFPM) electric motor,...
The paper analyses the power quality in power substations from residential and educational buildings (campus university). Measurements were performed in two days, one in a weekday, and one in a weekend, to highlight differences. Measurements in the power substation were performed using power quality analyser. Electrical measurements were performed for voltages and currents spectra, Fresnel diagrams,...
The purpose of designing this system is to regulate the speed of three-phase asynchronous motor of the platform in three ways: automatically (in this way speed profile is a profile imposed by the user at the beginning of motor start), manually (in this way speed profile can be chosen either from the potentiometer, or the display panel HMI) or in “GSM” (in this way, the GPRS module receives the SMS...
The present paper investigates the influence of elasticity on drop dynamics and detachment in a viscous outer liquid. Viscous and viscoelastic fluids are injected at constant flow rate through a capillary nozzle in mineral oil. The drop and thread formation are visualized until the drop attains constant velocity. The main goal was to measure the distance between the nozzle and the moving drop, prior...
A study on the possible corrections of the measured magnetization curves for magnetite (Fe3O4) nanoparticles is presented. The same nanopowder was measured using various sample shapes (cylinders, thin films) allowed by the VSM holders, which impose a specific packing fraction, and under different orientations of the applied magnetic field. Demagnetizing factors and effective field approaches are tried,...
With rapid advancement of artificial intelligence via evolutionary optimization, multilevel thresholding has become a feasible and critical way for image segmentation. Genetic Algorithms (GAs) and Particle Swarm Optimization (PSO) are two dominating schemes for multilevel thresholding, which group image pixels into multiple classes in terms of the intensity level of each pixel. However, majority segmentation...
The paper describes the implementation in ORCAD of equivalent circuits, used to model an artificially created frequency response function. The function is implemented and graphically represented in Matlab. Next, we compute the input admittance/impedance of the two proposed equivalent circuits (that include controlled sources), and compare it to the initial function. Finally, we conclude that this...
The objective of the paper is the presentation of a laboratory model of a system for active filtering and regeneration (SISFREG) developed through an applied research collaborative project in the frame of Partnerships in priority area programme during 2014–2016. The system allows the conversion of the DC traction substations into “active substations”. The main component of the laboratory model is...
Apparently, immunity tests applied to electronic equipment are theoretically simple and repeatable. These tests are standardized, but the major problem is related on different results, even if testing conditions are rigorous the same. It is important to evaluate the electrostatic charges accumulation and the subsequent discharges on protection devices in order to avoid damages even at the design stage...
In this paper, the electrical resistivity (determined with absorption/resorption currents) is used as a diagnostic factor in order to assess the mineral oil condition and to evaluate its elapsed and remaining lifetimes. Based on experimental results of thermal accelerated ageing, the lifetime values at constant temperature are calculated by the IEC and activation energy methods. The chosen end-of-life...
Two systematic adaptive control approaches are applied for tracking and regulating the Lorenz chaotic system. The adaptive synchronization approach is implemented with 3 individual controllers used in the Lyapunov function design. The adaptive backstepping control is also introduced with a single controller at much less control efforts. The asymptotic stability for both proposed control laws has been...
The primary goal of our study is to model the plant cover influence on water and soil erosion dynamics. The mathematical model consists in Saint-Venant equations coupled with the multiple particle class Hairsine-Rose soil erosion model. The numerical solutions are obtained from a finite volume scheme used to discretize the continuum model, where a second order fractional time step is applied for time...
The paper explores the main directions in which the augmented reality and the Web can change the approach in power engineering and significantly improving it. These innovations facilitate, in a user-friendly way, the availability of real-time data, fast processed information, assistance and guidance at any time and in any place along the entire energy chain. A step-by-step implementation of AR applications...
Non-linear power sources have become very popular nowadays, being widely present in almost all electronic devices connected to the power supply grid. Distorted nature of these types of loads has strongly influenced the electrical power quality by generating high levels of harmonics in the current and voltage waveforms of the power systems. As these levels are quantified by the Total Harmonic Distortion...
In this paper is presented a statistical analysis of the sound power emitted by power transformers. The power of the analyzed transformers within this analysis is greater than 6 MVA in no-load operation when the cooling system is turned off. Using this statistical approach the complex multiphysics problem of estimating the transformer sound power is greatly simplified.
This paper proposes simple models of high computational efficiency for Transcranial Magnetic Stimulation (TMS). Since the magnetic field is produced by currents of low frequency, the physical model is based on a unidirectional coupling between a Magneto-“Steady-state” (MG) formulation and an Electric Conduction (EC) formulation. The coupling is ensured by the Faraday's law of induction and it is unidirectional...
The PPM (Prediction by Partial Matching) methods are applied before the lossless compression algorithms, as a preprocessing procedure for the text in order to use efficiently the redundancy. This paper presents 4 compression algorithms preceded by 3 different PPM methods. The compression ratio is studied in relation with the file size, its content, and the context order (the prediction degree). Some...
As digital life became more intertwined with our daily activities, humans developed an increasing reliance on cloud computing to sync data between all their devices, acquired 24/7 access to information through the internet, as well as the ability to share data from anywhere using a variety of methods. Predictably, technology began to exert its influence in education, with new practices of large-scale...
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