1. Removal of inclusions and trace elements from Al-Mg-Si alloys using refining fluxeUroš Kovačec, Franc Zupanič, 2025, original scientific article Abstract: The cleanliness of aluminium alloys has a decisive effect on their properties and performance. In this work, the melts of several Al-Mg-Si alloys (6xxx series) were refined using rotary flux injection (RFI) of the salt fluxes in the industrial environment. A typical charge consisted of 25 % to 30 % external scrap, 45 % to 50 % internal scrap, and 20 % to 30 % primary aluminium. During injection, the entire melt volume was mixed uniformly. The melt was filtered using a porous ring filtration apparatus. The fraction and type of non-metallic inclusions were determined using light and scanning electron microscopy. The contents of alkali and alkaline-earth metals were determined using optical emission spectroscopy. The reduction of alkali and alkaline earth metals and the fraction of nonmetallic inclusions were used to evaluate the process efficiency and the flux selection for the regular production. An analysis of more than 100 industry charges confirmed that the flux selected after the experimental trials, consisting of a mixture of MgCl2, KCl, NaCl and CaF2, was effective in regular production.
Keywords: aluminium, refinement, flux, cleanlines, non-mtalic inclusion, rotary injection, alkall element
Published in DKUM: 04.12.2025; Views: 0; Downloads: 7
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2. Cogging torque reduction techniques in axial flux permanent magnet machines : a reviewFranjo Pranjić, Peter Virtič, 2024, review article Abstract: Axial flux permanent magnet machines have garnered significant attention in recent years due to their numerous advantages in various applications, including electric vehicles, wind turbines, and robotics. However, one of the critical challenges associated with these machines is the presence of cogging torque, which can hinder their efficiency and performance. This review article provides a comprehensive overview of the state-of-the-art techniques employed for cogging torque reduction in Axial Flux Permanent Magnet Machines. Different techniques are described, encompassing geometric optimization, magnet placement, and skewing methods. Firstly, the significance of Axial Flux Permanent Magnet Machines is described, as well as the issue of the cogging torque. In the methods section, a review of the strategies for the reduction of cogging torque is described from various articles, and finally, in the discussion section, a list of actions is presented for cogging torque reduction for different topologies. The novelty of the study is that it combines strategies for cogging torque reduction in a single article.
Keywords: cogging torque, axial flux permanent magnet machines, geometric optimization, magnet placement strategies, skewing techniques
Published in DKUM: 06.11.2025; Views: 0; Downloads: 3
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3. Magnetic flux density measurement platform for an inductive wireless power transmitter coil designNataša Prosen, Miro Milanovič, Jure Domajnko, 2022, original scientific article Abstract: This paper presents a platform developed for automated magnetic flux density measurement. The platform was designed to be used to measure the magnetic flux density of the
transmitter/receiver coil of an inductive wireless power transfer system. The magnetic flux density
of a transmitter was measured using a small, 3-axis search coil. The search coil was positioned in
the 3D space above the transmitter coil using a 3D positioning mechanism and used to measure
the magnetic flux density at a specific point. The data was then sent to a computer application to
visualize the magnetic flux density. The measured magnetic field could be used in combination with
electromagnetic field solvers to design and optimize transmitter coils for inductive wireless power
transfer systems.
Keywords: magnetic field, magnetic flux density, IPT, transmitter coil design, EM solver
Published in DKUM: 01.04.2025; Views: 0; Downloads: 7
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4. Measuring system for determining the quality of LED light sources and an overview of LED light bulbs for household useMatic Markovič, Andrej Orgulan, Primož Sukič, 2022, original scientific article Abstract: Modern LED light sources have many advantages, as well as some disadvantages. One of
the disadvantages is the pulsating luminous flux, which, in some cases, affects people’s health and
well-being negatively. The paper describes the design and making process of a measuring system
for determining the quality of LED substitutes for conventional light bulbs and gives an overview
of LED light bulbs for household use. The measurement system is controlled using the MATLAB
software environment, in which data processing and plotting of the results are also performed. We
acquired 59 different LED light bulbs from 37 manufacturers, and performed the measurements.
The light bulbs are classified based on the percentage of fluctuations in the luminous flux, and the
percentage of deviation of the measured luminous flux compared to the value stated on the packaging
by the manufacturer.
Keywords: angular distribution of light, fluctuations in the luminous flux, LED light quality, measuring system, Red Pitaya
Published in DKUM: 01.04.2025; Views: 0; Downloads: 13
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5. Determination of neutron flux redistribution factors for a typical pressurized water reactor ex-core measurements using Monte Carlo techniqueTanja Goričanec, Bor Kos, Klemen Ambrožič, Andrej Trkov, Luka Snoj, Marjan Kromar, 2023, original scientific article Abstract: In a typical pressurized water reactor, neutron detectors located outside the reactor core monitor reactor power. In addition, they are also used to measure the reactivity of the control rods. A novel approach to calculate the ex-core neutron detector response in a typical pressurized water reactor using the Monte Carlo technique is presented. A detailed ex-core model of the Krško nuclear power plant was developed using the Monte Carlo neutron transport code MCNP. Due to the location of the ex-core neutron detectors, the hybrid code ADVANTG is used to generate variance reduction parameters to accelerte the convergence of the results outside the reactor core. To use ADVANTG, the fixed neutron source had to be reconstructed from the criticality core calculation. This paper presents the sensitivity analysis of the response of the ex-core detectors to the neutron data libraries used, the description of the fixed neutron source and the ADVANTG parameters. It was found that a pin-wise description of the neutron source for at least two rows of fuel assemblies at the core periphery is necessary for accurate results. Our results show the importance of a correct description of the prompt neutron spectra in the high energy region and the impact this has on the response of the ex-core detectors. The method in which the prompt neutron fission spectra for important fission nuclides are weighted by the calculated reaction rates has been shown to be the best approximation, with deviations from the reference calculation within statistical uncertainty. The effect of nuclear data libraries on the response of the ex-core detector was investigated, and the difference between the ENDF/B-VII.0 and the ENDF/B-VIII.0 nuclear data libraries was ∼11%. When the deficient evaluation of the 56Fe isotope included in the ENDF/B-VIII.0 nuclear data library was replaced by the improved evaluation from the IAEA INDEN project, the differences decreased to ∼3.7%. In addition, neutron flux redistributions due to control rod movement were investigated and flux redistribution factors were updated using Monte Carlo particle transport methods. The reaction rate redistribution factors obtained with methods presented in this paper are within 1% agreement with the currently used factors.
Keywords: MCNP, ADVANTG, pressurized water reactor, Monte Carlo neutron transport, control rod, neutron flux redistribution factor, rod insertion, krško nuclear power plant
Published in DKUM: 29.11.2024; Views: 0; Downloads: 12
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6. Numerično določanje karakteristik sinhronskega motorja z različnimi velikostmi trajnih magnetov : magistrsko deloDavor Car, 2024, master's thesis Abstract: Magistrsko delo obravnava osnovni pristopa k modeliranju in konstruiranju sinhronskega motorja s trajnimi magneti s pomočjo računalniškega programa Flux. Izvedena je numerična analiza konstrukcijskih parametrov trajnih magnetov na navorno karakteristiko motorja. Analiza zajema vpliv različnih dimenzij in postavitev magnetov na vrednost valovitosti navora in razmerje navora proti volumnu trajnih magnetov. Rezultati nakazujejo, da je s predstavljenim računalniško podprtim pristopom, moči že v fazi načrtovanja motorja izbrati najustreznejše dimenzije za doseganje čim boljšega izkoristka z želeno navorno karakteristiko.
Keywords: Elektromotor, sinhronski stroj, sinhronski motor s trajnimi magneti, STSM, modeliranje, Flux, MKE, metoda končnih elementov, navitje, trajni magneti, valovitost navora, razmerje navora na volumen
Published in DKUM: 01.07.2024; Views: 136; Downloads: 69
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7. Cationised fibre-based cellulose multi-layer membranes for sterile and high-flow bacteria retention and inactivationVanja Kokol, Monika Kos, Vera Vivod, Nina Gunde-Cimerman, 2023, original scientific article Abstract: Low-cost, readily available, or even disposable membranes in water purification or downstream biopharma processes are becoming attractive alternatives to expensive polymeric columns or filters. In this article, the potential of microfiltration membranes prepared from differently orientated viscose fibre slivers, infused with ultrafine quaternised (qCNF) and amino-hydrophobised (aCNF) cellulose nanofibrils, were investigated for capturing and deactivating the bacteria from water during vacuum filtration. The morphology and capturing mechanism of the single- and multi-layer structured membranes were evaluated using microscopic imaging and colloidal particles. They were assessed for antibacterial efficacy and the retention of selected bacterial species (Escherichia coli, Staphylococcus aureus, Micrococcus luteus), differing in the cell envelope structure, hydrodynamic biovolume (shape and size) and their clustering. The aCNF increased biocidal efficacy significantly when compared to qCNF-integrated membrane, although the latter retained bacteria equally effectively by a thicker multi-layer structured membrane. The retention of bacterial cells occurred through electrostatic and hydrophobic interactions, as well as via interfibrous pore diffusion, depending on their physicochemical properties. For all bacterial strains, the highest retention (up to 100% or log 6 reduction) at >50 L/h∗bar∗m2 flow rate was achieved with a 4-layer gradient-structured membrane containing different aCNF content, thereby matching the performance of industrial polymeric filters used for removing bacteria.
Keywords: fibrous membrane, cationised cellulose nanofibrils, amino-hydrophobised cellulose nanofibrils, antibacterial activity, multi-layer structure, flux, bacteria retention
Published in DKUM: 28.03.2024; Views: 220; Downloads: 12
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8. Development of mathematical models in explicit form for design and analysis of axial flux permanent magnet synchronous machinesFranjo Pranjić, Peter Virtič, 2020, original scientific article Abstract: This article proposes a methodology for the design of double-sided coreless axial flux permanent magnet synchronous machines, which is based on a developed model for calculating the axial component of the magnetic flux density in the middle of the distance between opposite permanent magnets, which also represents the middle of the stator. Values for different geometric parameters represent the input data for the mathematical model in explicit form. The input data are calculated by using a simplified finite element method (FEM), which means that calculations of simplified 3D models are performed. The simplified model consists of two rotor disks with surfacemounted permanent magnets and air between them, instead of stator windings. Such a simplification is possible due to similar values of permeability of the air and copper. For each simplified model of the machine the axial component of the magnetic flux density is analyzed along a line passing through the center of opposite permanent magnets and both rotor disks. Values at the middle of the distance between the opposite permanent magnets are the lowest and are therefore selected for the input data at different stator, rotor disks and permanent magnets (PM) thicknesses. Such input data enable the model to consider the nonlinearity of materials.
Keywords: axial flux, analysis, coreless, development, design, explicit form, finite element method, mathematical models, permanent magnet, synchronous
Published in DKUM: 01.12.2023; Views: 498; Downloads: 40
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10. Experimental verification of the numerically determined parameters for the non-linear two-axis model of a synchronous motor with interior permanent magnetsŽeljko Hederić, Venco Ćorluka, Toni Varga, 2021, original scientific article Abstract: Synchronous machines belong to the family of electrical machines characterised by a synchronous magnetic rotating field in the air gap of the machine, the speed of which depends on the frequency of the currents in the armature winding. The paper presents procedures and methods for the numerical determination and experimental verification of the parameters for a nonlinear two-axis model of a synchronous motor with permanent magnets in the rotor (IPMSM) and a concentrated stator winding. To calculate the distribution of electro-magnetic fields in the motor accurately, models with distributed parameters are used in motor design, for which the Finite Element Method (FEM) is usually employed. The improvement by using the model with concentrated parameters considerably simplifies the physical model, by describing it with a system of (non)linear differential equations, the so‐called partial differential equations, which is presented in this paper.
Keywords: synchronous motor, flux linkage, interior permanent magnets, non-linear
Published in DKUM: 13.11.2023; Views: 238; Downloads: 5
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