1. 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, izvirni znanstveni članek Opis: 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.
Ključne besede: MCNP, ADVANTG, pressurized water reactor, Monte Carlo neutron transport, control rod, neutron flux redistribution factor, rod insertion, krško nuclear power plant
Objavljeno v DKUM: 29.11.2024; Ogledov: 0; Prenosov: 2
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2. Avtomatizacija procesa: aplikacija za izdelavo laserskih dokumentov za električne števceMark Kern, 2024, diplomsko delo Opis: Problemi, ki smo jih želeli rešiti v podjetju, so avtomatsko dodeljevanje kod za maske, omogočanje generiranja mask s kupcem in prodajnikom na terenu in omogočanje določenim kupcem, da si sami naredijo masko brez pomoči tehnične prodaje. S tem smo razbremenili in sčasoma bomo zamenjali osebje, ki zdaj dela ročno maske in zmanjšali možnosti napake.
Rezultat je spletna aplikacija, s katero bodo lahko prodajniki, tehnična prodaja in kupci generirali maske, zaradi česar je proces veliko hitrejši in možnost za napake manjša. Najučinkovitejši je sistematični pristop k reševanju tega problema, s pomočjo orodja Power Apps smo lahko naredili zelo modularno aplikacijo, ki jo bomo lahko nadgrajevali in povezovali z našimi drugimi sistemi. Pomembno je bilo, da smo najprej raziskali najboljšo metodo, s pomočjo katere smo ta problem rešili. Rešitev je morala biti zelo modularna ter podprta z že obstoječimi procesi in orodji. Raziskati smo morali, kako obširen je problem, da smo našli ustrezno rešitev, saj je bilo treba preveriti, ali se bo sama aplikacija nadgrajevala na določeno periodo ali jo bomo po razvoju zaključili z nadgradnjo. Glede programske rešitve smo se odločili, da bomo uporabili Power Apps, ki izpolnjuje vse zahteve in se najbolje integrira v naš sistem. Ko smo pridobili vse potrebne podatke, smo začeli razvijati aplikacijo. Med samim razvojem smo izvajali teste in nadgradnje. S kupci smo preverjali in interno testirali procese, dokler aplikacija ni bila dokončno zaključena.
Ključne besede: avtomatizacija procesov, generiranje mask, modularna aplikacija, Power Apps, električni števci
Objavljeno v DKUM: 15.11.2024; Ogledov: 0; Prenosov: 2
Celotno besedilo (1,36 MB) |
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4. Quantifying power system frequency quality and extracting typical patterns within short time scales below one hourYounes Mohammadi, Boštjan Polajžer, Roberto Chouhy Leborgne, Davood Khodadad, 2024, izvirni znanstveni članek Ključne besede: quantifying power system frequency quality, statistical indices, pattern extracting, machine learning, short time scales, renewable energy sources
Objavljeno v DKUM: 23.08.2024; Ogledov: 50; Prenosov: 5
Celotno besedilo (12,67 MB) |
5. Methods and models for electric load forecasting : a comprehensive reviewMahmoud A. Hammad, Borut Jereb, Bojan Rosi, Dejan Dragan, 2020, izvirni znanstveni članek Opis: Electric load forecasting (ELF) is a vital process in the planning of the electricity industry and plays a crucial role in electric capacity scheduling and power systems management and, therefore, it has attracted increasing academic interest. Hence, the accuracy of electric load forecasting has great importance for energy generating capacity scheduling and power system management. This paper presents a review of forecasting methods and models for electricity load. About 45 academic papers have been used for the comparison based on specified criteria such as time frame, inputs, outputs, the scale of the project, and value. The review reveals that despite the relative simplicity of all reviewed models, the regression analysis is still widely used and efficient for long-term forecasting. As for short-term predictions, machine learning or artificial intelligence-based models such as Artificial Neural Networks (ANN), Support Vector Machines (SVM), and Fuzzy logic are favored.
Ključne besede: methods, models, electric load forecasting, modeling electricity loads, electricity industry, power management, logistics
Objavljeno v DKUM: 22.08.2024; Ogledov: 95; Prenosov: 8
Celotno besedilo (1,23 MB)
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6. Optimization of a circular planar spiral wireless power transfer coil using a genetic algorithmNataša Prosen, Jure Domajnko, 2024, izvirni znanstveni članek Opis: Circular planar spiral coils are the most important parts of wireless power transfer systems. This paper presents the optimization of wireless power transfer coils used for wireless power transfer, which is a problem when designing wireless power transfer systems. A single transmitter coil transfers power to a single receiving side. The performance of the wireless power transfer system depends greatly on the size and shape of the wireless power transfer system. Therefore, the optimization of the coils is of the utmost importance. The main optimization parameter was the coupling coefficient between the transmitter and the receiver coil in the horizontally aligned and misaligned position. A genetic evolutionary algorithm was used to optimize the coil, according to the developed cost function. The algorithm was implemented using the MATLAB programming language. The constraints regarding the design of the coils are also presented for the problem to be analyzed correctly. The results obtained using the genetic algorithm were first verified using FEM simulations. The optimized coils were later fabricated and measured to confirm the theory.
Ključne besede: wireless power transfer, coil optimization, genetic algorithm, coupling coefficient measurement
Objavljeno v DKUM: 14.08.2024; Ogledov: 77; Prenosov: 9
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8. Lower-limb muscle contractile properties, explosive power and the subjective response of elite soccer players to the Covid-19 lockdownArmin Paravlić, Boštjan Šimunič, Saša Pišot, Matej Kleva, Kaja Teraž, Matjaž Vogrin, Uroš Marušič, Rado Pišot, 2022, izvirni znanstveni članek Opis: The present study examined the effects of the lockdown period on basic anthropometric measures, countermovement jumping performance, skeletal muscle contractile properties derived from tensiomyography (TMG), injury incidence, and self-assessed general well-being in elite soccer players. A total of 266 players were assessed before (PRE) and 32 players were reassessed 11 days after (POST) the COVID-19 period. Significant changes in the TMG parameters were observed POST compared to PRE: contraction time (Tc) increased from 6% to 50% in vastus lateralis [VL] (p = 0.009) and biceps femoris [BF] (p < 0.001), respectively; whereas radial displacement (Dm) increased for 19% in BF (p = 0.036) and 17% in VL (p < 0.001), respectively. Jumping performance remained unchanged from PRE to POST In addition, athletes rated the lockdown period as a positive event and felt psychologically better during the lockdown, primarily because they spent more time with family members and friends. Although there were no differences in any of the variables describing lower limb muscle power following the two-month lockdown, the altered contractile properties of the assessed muscles suggest suboptimal conditioning of the football players.
Ključne besede: football, male football, power, explosive power, CMJ, tensiomyography, SJ, coronavirus, pandemics, lockdown
Objavljeno v DKUM: 11.07.2024; Ogledov: 80; Prenosov: 8
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9. Utilisation of renewable electricity to produce synthetic methaneKlemen Rola, Sven Gruber, Danijela Urbancl, Darko Goričanec, 2023, izvirni znanstveni članek Ključne besede: power-to-methane, P2M, synthetic methane, CO2 methanation, Aspen Plus, Aspen Adsorption
Objavljeno v DKUM: 18.04.2024; Ogledov: 203; Prenosov: 11
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10. Dimensional deviations in Ti-6Al-4V discs produced with different process parameters during selective laser meltingSnehashis Pal, Marijana Milković, Riad Ramadani, Janez Gotlih, Nenad Gubeljak, Radovan Hudak, Igor Drstvenšek, Matjaž Finšgar, Tomaž Brajlih, 2023, izvirni znanstveni članek Opis: When manufacturing complicated products where both material and design play a role, especially thin and curved components, it is difcult to maintain accurate dimensions in Selective Laser Melting. Considering these difculties, this article presents the dimensional errors in the fabrication of Ti-6Al-4V discs and their thermomechanics during manufacturing. Various combinations of laser processing parameters were used to fabricate the 2.00 mm thick discs with a diameter of 5.70 mm. It was found that the thickness shortened and the round shape changed to an oval shape for most of the discs. The thickness decreased along the build-up direction from the bottom to the top and formed a taper that increased with increasing energy density (ED). The horizontal diameter of the discs changed slightly, while the vertical diameters changed remarkably with increasing ED. On the other hand, reducing the laser power resulted in a reduction of the roundness error, while it caused a reduction of the thickness. The hatch spacing signifcantly afected the volume of the melt pool and caused a change in the vertical diameter. The central part of the curved surface of the discs became concave and the concavity increased due to the increasing ED.
Ključne besede: dimension, Ti-6Al-4V, lase power, scanning speed, hatch spacing, selective laser melting
Objavljeno v DKUM: 29.03.2024; Ogledov: 219; Prenosov: 9
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