1581. Selective seperation of magnesium from Slovenian dolomitesJernej Imperl, Mitja Kolar, Vilma Ducman, Gorazd Žibret, Lea Žibret, 2025, published scientific conference contribution Abstract: Although magnesium is one of the most abundant elements on Earth by weight, the demand for magnesium is constantly increasing due to its widespread use in a diverse range of industries such as metal alloys, electronics, batteries, agricultural and pharmaceutical compounds. For this reason, magnesium is categorised as a critical raw material by the European Union. Dolomite CaMg(CO3)2 is one of the most important mineral sources of magnesium, which in its pure form contains 13.18 % magnesium by weight. Various pyrometallurgical and hydrometallurgical processes have been developed and are used to extract magnesium from dolomite and other magnesium ores. In this study, samples of dolomite of different geological ages were collected in Slovenia and their elemental composition was analysed by microwave-assisted acid digestion and ICP-OES. Magnesium was then extracted by selective leaching and selective precipitation. Leaching was carried out with inorganic and organic acids. The separation of magnesium and calcium in a solution prepared by dissolving dolomite with acid was carried out by precipitation with hydroxide and oxalate. High extraction yields of magnesium and a significant separation between the two metals were achieved with both methods.
Keywords: magnesium, dolomite, extraction, selective leaching, selective precipitation
Published in DiRROS: 16.07.2025; Views: 415; Downloads: 240
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1582. Investigating the thermal penetration in structural timber elements exposed to natural firesAndrea Lucherini, Vladimír Mózer, 2025, published scientific conference contribution Abstract: This study investigates fire-induced charring and thermal penetration in structural timber elements exposed to natural fire conditions, with a focus on the critical role of the cooling phase. A simplified 1D heat transfer model, based on Eurocode 5 temperature-dependent material properties, is implemented to simulate the thermal response of timber members subjected to Eurocode parametric fire curves. The analysis quantifies the char depth (300 °C isotherm) and the zero-strength layer, using both temperature-based (80-300 °C and 120-300 °C) and reduced mechanical properties approaches (tension and compression). Results show that, while the char depth predominantly develops during the heating phase, the zero-strength layer continues to grow during cooling, often reaching a thickness comparable to the char layer. The effective char depth (char depth + zero-strength layer) typically reaches its maximum towards the end of the cooling phase, representing the most critical condition for load-bearing capacity. The most severe conditions arise in low ventilation and high fuel load scenarios, characterised by long-duration fires rather than the highest temperatures. The findings highlight the need to explicitly consider the cooling phase in performance-based fire design for timber structures.
Keywords: timber structures, fire safety, charring, zero-strength layer, cooling
Published in DiRROS: 16.07.2025; Views: 384; Downloads: 258
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1583. Circularity and longevity of alkali-activated materials : case-study using rock wool as a precursorBarbara Horvat, Sara Tominc, 2025, published scientific conference contribution Abstract: Alkali-activated materials (AAMs) are being envisaged as a future alternative to cements because AAMs (i) can be made solely from locally available secondary raw materials and (ii) because of their low energy consumption during synthesis. However, products that cannot be reused should never enter the market. Therefore, the circular economy viability of AAMs was studied by reusing (alkali-activated) pulverised rock wool in alkali activation synthesis until the theoretically determined limit leading to the efflorescence would be reached. While 25% of the maximal allowed liquid alkali did not offer significant mechanical performance, 50, 75 and 100% of allowed alkali ended up with 15, 20 and 20 MPa, respectively, which is only 5 MPa lower than AAM made with the same technique (pressing) in a one-step approach. Therefore, if the initial AAM does not reach the efflorescence limit, it could still be used as a precursor before it becomes waste.
Keywords: kamena volna, alkalijsko aktivirani materiali, mikrovalovno obsevanje, elektromagnetna dehidracija, krožni modeli, linearni modeli
Published in DiRROS: 16.07.2025; Views: 450; Downloads: 242
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1587. Občina Ajdovščina s protipožarnimi objekti 1:40.000Jaša Saražin, Gašper Ogrin, 2025, dictionary, encyclopaedia, lexicon, manual, atlas, map Abstract: Deležniki s področja upravljanja s požari v naravnem okolju z zahodnega območja Slovenije so večkrat izpostavili potrebo po ažuriranem kartnem gradivu za potrebe izvajanja preventivnih in intervencijskih ukrepov za omejevanje požarov v naravnem okolju. Tako gasilstvo kot tudi civilna zaščita sta v Sloveniji v prvi meri organizirana na občinskem nivoju. Zasledujoč ta dva okvira je nastal dotični zemljevid, ki prikazuje celotno območje občin Ajdovščina in Vipava.
V merilu 1 : 40.000 (v primeru tiska 80 cm X 106 cm), nudi širšo sliko, ki je potrebna tako pri orientaciji enot na terenu, lociranju požarov v naravnem okolju, strateškemu načrtovanju pri večjih intervencijah, ali pri koordinaciji več sočasnih dogodkov. Tovrsten večji format zemljevida nudi odlično dopolnitev k obstoječemu Atlasu protipožarnih objektov (2021) in predstavlja novo inovativno možnost podajanja informacij o protipožarnih objektih.
Opozorilo: Poudariti pa je potrebno, da so prikazani podatki preverjeni le za območje občine Ajdovščina, za preostala prikazana območja pa zgolj informativne narave. Nekatere prikazane prometnice imajo omejen prometni režim, po katerih je vožnja dovoljena le pooblaščenim uporabnikom.
Zahvala: Zemljevid je nastal v sklopu Interreg projekta Wildfire CE—Enabling cross-boundary assessment, communication and management of wildfire risks in Central Europe (št projekta: CE0200934), s sodelovanjem Gozdarskega inštituta Slovenije, Občine Ajdovščina in Zavoda za Gozdove Slovenije. Komentarje, ki so prispevali h končni podobi zemljevida pa so prispevali tudi predstavniki GRC Ajdovščina.
Keywords: tematski zemljevidi, Ajdovščina, požarna varnost
Published in DiRROS: 15.07.2025; Views: 417; Downloads: 223
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1590. Moč uma in telesa : telo kot politični prostor v desetletju po 1. svetovni vojni na SlovenskemPavlina Bobič, 2024, original scientific article Abstract: Prispevek tematizira ideale in perspektive telesnosti v obdobju pred in po prvi svetovni vojni in jih postavlja v okvir sočasnih poskusov celovite povojne obnove življenj. Na kakšne načine se je princip telesnosti spreminjal v politično krajino, kjer so se spopadle različne ideologije in obenem razkrile svoje poglede na duhovno in telesno moč ter sposobnost (moralne) regeneracije?Tradicionalna ikonografija je črpala iz bogate duhovne in sekularne dediščine ter se klesala ob predstavah o vzgojnih prijemih in pasteh dobe. Dileme so se znotraj sokolskih in orlovskih telesnovzgojnih vsebin prepletale s političnimi, desetletja trajajoča razhajanja med obema organizacijama pa so se še zaostrile v času državljanskega spopada ter poglobila razdor v tradicionalnem taboru med drugo svetovno vojno.
Keywords: prva svetovna vojna, povojna moralna obnova, koncepti telesnosti, škof Anton Bonaventura Jeglič, Filip Terčelj, Sokol, Orel.
Published in DiRROS: 15.07.2025; Views: 347; Downloads: 155
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