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Opis: This study examined the melting behavior and flowability of pure magnesium during selective laser melting. The potential to increase product density was also investigated. Various combinations of manufacturing parameters were considered. The laser power was gradually increased in different machine runs, with different scanning speeds for each run to vary the energy density (ED). The laser power ranged from 10 W to 75 W, and the scanning speed ranged from 100 mm/s to 800 mm/s. Lower laser powers resulted in poor melting, while higher laser powers produced better melting, with significant differences even when the ED was the same. High EDs between 3.50 J/mm² and 4.30 J/mm² led to a lack of melting at low laser power and to an unstable melt pool with significant spattering at high laser power. In contrast, moderate EDs in the range of 1.40 J/mm² to 2.90 J/mm² resulted in better density at high laser power. Higher scanning speeds helped to avoid the formation of a dense smog cloud and provided sufficient energy in a short time with the aid of higher laser power. Therefore, increasing both laser power and scanning speed improved melting performance and increased product density. The relative product density ranged from 80 % to 96.5 %. Reducing the layer thickness from 50 µm to 25 µm at a laser power of 40 W resulted in the formation of a well-formed melt pool in some areas and significant melt spattering in others, which led to a deterioration in density.
Ključne besede: magnesium, melt pool, laser power, scanning speed, layer thickness, support structure, laser powder bed fusion
Objavljeno v DKUM: 09.12.2025; Ogledov: 0; Prenosov: 2
Celotno besedilo (3,08 MB)
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Opis: This article presents the development and implementation of an IoT-enabled, off-grid solar power supply prototype designed to power a range of electrical devices. The developed system comprises a Photovoltaic panel, a Maximum Power Point Tracking (MPPT) charger, a 2.5 kWh/24 V high-performance LiFePO4 battery bank with a Battery Management System, an embedded controller with IoT connectivity, and DC/DC and DC/AC converters. The PV panel serves as the primary energy source, with the MPPT controller optimizing battery charging, while the DC/DC and DC/AC converters supply power to the connected electrical devices. The article includes a case study of a developed platform for powering an information and advertising system. The system features a predictive energy management algorithm, which optimizes the appliance operation based on daily solar irradiance forecasts and real-time battery State-of-Charge monitoring. The IoT-enabled controller obtains solar irradiance forecasts from an online meteorological service via API calls and uses these data to estimate energy availability for the next day. Using this prediction, the system schedules and prioritizes the operations of connected electrical devices dynamically to optimize the performance and prevent critical battery discharge. The IoT-based controller is equipped with both Wi-Fi and an LTE modem, enabling communication with online services via wireless or cellular networks.
Ključne besede: energy consumption control, forecasted solar irradiation, power management, off-grid power supply, photovoltaic, solar, IoT, LTE, Wi-Fi, ESP32
Objavljeno v DKUM: 14.11.2025; Ogledov: 0; Prenosov: 6
Celotno besedilo (5,16 MB)

Opis: To address the growing integration of renewable energy sources and storage systems into distribution networks, there is a need for effective tools that can assess the impact of these technologies on grid performance. This paper investigates the impact of integrating residential rooftop photovoltaic (PV) systems and battery energy storage systems (BESSs) into low-voltage (LV) distribution networks. A stochastic approach, using the Monte Carlo method, is applied to randomly place PV systems across the network, generating multiple scenarios for power flow simulations in MATLAB Simulink R2024b. The method incorporates real-world consumer load data and grid topology, representing a novel approach in simulating distribution network behaviour accurately. The novelty of this paper lies in its ability to combine stochastic PV placement with real-world load data, providing a more realistic representation of network conditions. The simulation results revealed that widespread PV deployment can lead to overvoltage issues, but the integration of BESSs alongside PV systems mitigates these problems significantly. The findings of this paper offer valuable insights for Distribution Network Operators, aiding in the development of strategies for optimal PV and BESS integration to enhance grid performance.
Ključne besede: photovoltaic system, battery energy storage system, low-voltage distribution network, Monte Carlo method, power flow
Objavljeno v DKUM: 03.11.2025; Ogledov: 0; Prenosov: 7
Celotno besedilo (3,19 MB)
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Opis: Diplomska naloga obravnava razvoj aplikacije za upravljanje terminov v okolju Microsoft Power Apps, namenjene digitalizaciji internih rezervacijskih procesov znotraj organizacije. V uvodu je opredeljen problem ročnega upravljanja terminov, ki pogosto povzroča neučinkovitosti in napake. Cilj naloge je bil zasnovati nizkokodno rešitev, s katero se upravljanje izobraževanj, prijav ter obveščanja zaposlenih poenostavi in izboljša. Dodana vrednost razvite aplikacije je v hitrejšem izvajanju prijavnih procesov ter v podpori nadaljnji digitalizaciji organizacijskih procesov. Zaključki naloge izpostavljajo, da nizkokodni razvoj predstavlja ustrezno metodologijo za razvoj poslovnih rešitev, ki ne zahtevajo poglobljenega programerskega znanja in zagotavljajo visoko stopnjo prilagodljivosti in avtomatizacije.
Ključne besede: upravljanje terminov, nizkokodni razvoj, digitalizacija, Microsoft Power Apps, Microsoft Power Platform
Objavljeno v DKUM: 21.10.2025; Ogledov: 0; Prenosov: 10
Celotno besedilo (1,84 MB)

Opis: The integration of photovoltaic systems into power grids can impact power quality, particularly concerning voltage and current harmonics. This study investigates the power quality of a photovoltaic system integrated into the electrical system of an educational facility, focusing on harmonic distortion in both voltage and current. Comprehensive measurements were conducted across three phases and analysed according to the EN 50160 and IEEE 519 Standards. The results demonstrated that, while the voltage quality meets EN 50160 requirements consistently, indicating stable voltage levels, the current measurements revealed significant harmonic distortion. Notably, Phase 2 exhibited Total Harmonic Distortion values substantially above the acceptable limits, with Phase 1 and Phase 3 also showing elevated Total Harmonic Distortion. To address these issues, the study recommends the implementation of advanced harmonic filters and optimisation of inverter technologies. These measures are crucial for enhancing power quality, and ensuring compliance with the industry Standards in high photovoltaic penetration scenarios.
Ključne besede: power quality analysis, grid-connected PV systems, EN 50160 standard, IEEE 519 Standard, IEC 61000 standard, voltage harmonics, current harmonics, harmonic distortion, renewable energy integration, compliance assessment
Objavljeno v DKUM: 01.10.2025; Ogledov: 0; Prenosov: 1
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