1. Estimation of measurement uncertainty for determination of sulphate content in cement by an alternative approachLina Završnik, Sabina Dolenec, 2016, izvirni znanstveni članek Povzetek: The precise and accurate determination of sulphate levels in cement is of utmost importance due to the potential occurrence of internal sulphate attack in concrete, which affects the latter’s durability, and thus, also the safety of concrete constructions. The estimated measurement uncertainty provides a level of confidence in the experimental results, and enables the comparison of data, both between different laboratories and between different methods. This paper presents an alternative approach to the estimation of measurement uncertainty in the determination of sulphate in cement, based on the use of proficiency testing data. The calculations used in this procedure refer to the estimation of reproducibility within-laboratory component of the analysis of control samples, as well as of the bias component of sulphate content data for different types of Portland cement derived from several proficiency testing trials.
Ključne besede: cement, sulphate, measurement uncertainty, alternative approach
Objavljeno v DiRROS: 03.03.2025; Ogledov: 137; Prenosov: 77
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2. Provenance analysis of Roman stone artefacts from sedimentary rocks from the archaeological site near Mošnje, NW SloveniaSnježana Miletić, Sabina Dolenec, Judita Lux, Andrej Šmuc, Nina Zupančič, 2016, izvirni znanstveni članek Povzetek: This study deals with the macroscopic and microfacies characterisation of Roman stone artefacts excavated in
2006 from a Roman villa rustica near Mošnje (NW Slovenia) with the aim of defining their provenance. A total of 28 representative finds (querns, mortars, whetstones, tooled and rounded stones, a fragment of stone slab, mosaic tesserae and two architectural elements - one with a relief) made of clastic and carbonate sedimentary rocks were examined. Comparison was made with rock samples taken from quarries and gravel bars close to the archaeological site, as well as from larger distance to the site. The majority of artefact sampled is composed of Upper Palaeozoic quartz sandstones, which are found as pebbles in gravel bars close to the archaeological site; while 2 samples were from Quaternary coarse grained clastic rocks which can be found in local glacio-fluvial Sediments. Other finds were made of four different Mesozoic shallow-water limestones which outcrop in different areas of Central and SW Slovenia. The nearest Lower Jurassic biopelmicritic limestones are found at the western periphery of Ljubljana in Podutik. Cretaceous miliolid limestones and biocalcarenitic limestones with rudists are common in the successions of the Dinaric Carbonate Platform in SW Slovenia (for example, on the Trieste-Komen Plateau), NE Italy and SW Croatia. This indicates that the limestones for architectural elements, stone mortars and tesserae were brought to Mošnje from distant locations. Smaller stone tools are likely to have been made at the location of the archaeological site from material gathered locally, mostly pebbles from clastic rocks, which were accessible and suitable for tooling.
Ključne besede: arheološke izkopanine, rimljani, sedimentne kamnine, apnenec, mikrofacies, izvor kamnine, arheološko najdišče, Slovenija
Objavljeno v DiRROS: 08.01.2025; Ogledov: 258; Prenosov: 129
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5. Pigment analysis of Roman wall paintings from two villae rusticae in SloveniaMaja Gutman, Katharina Zanier, Judita Lux, Sabina Dolenec, 2016, izvirni znanstveni članek Povzetek: The study deals with the characterisation of paint layers from the wall paintings that decorated two excavated Roman villae rusticae in Slovenia. The villa in Mošnje, located in the NW of Slovenia, was built in the 1st half of the 1st century AD and was in use until the end of the 2nd century AD, while the coastal villa in Školarice, built in the second quarter of the 1st century AD, remained in use until the mid-5th century. Stratigraphy and painting techniques were studied using optical microscopy, with pigments identified via Raman microspectroscopy supported by FTIR microspectroscopy and SEM/EDS. The results of this analysis revealed that whereas the Školarice wall paintings were mainly executed using the fresco technique and some areas with the secco technique, both techniques were identified equally in the Mošnje paintings. Red ochre, lime white and carbon black pigments were identified in both the Mošnje and Školarice paintings, although the latter were also characterised by the use of yellow ochre and green earth.
Ključne besede: Roman villas, mural painting, pigments, Raman microspectroscopy
Objavljeno v DiRROS: 16.09.2024; Ogledov: 393; Prenosov: 147
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6. Adsorption efficiency of cadmium (II) by different alkali-activated materialsNataša Mladenović Nikolić, Ljiljana Kljajević, Snežana B. Nenadović, Jelena Potočnik, Sanja Knežević, Sabina Dolenec, Katarina Trivunac, 2024, izvirni znanstveni članek Povzetek: The objective of this study was to demonstrate the potential utilization of fly ash (FA), wood ash (WA), and metakaolin (MK) in developing new alkali-activated materials (AAMs) for the removal of cadmium ions from waste water. The synthesis of AAMs involved the dissolution of solid precursors, FA, WA, and MK, by a liquid activator (Na2SiO3 and NaOH). In concentrated solutions of the activator, the formation of an aluminosilicate gel structure occurred. DRIFT spectroscopy of the AAMs indicated main vibration bands between 1036 cm−1 and 996 cm−1, corresponding to Si-O-Si/Si-O-Al bands. Shifting vibration bands were seen at 1028 cm−1 to 1021 cm−1, indicating that the Si-O-Si/Si-O-Al bond is elongating, and the bond angle is decreasing. Based on the X-ray diffraction results, alkali-activated samples consist of an amorphous phase and residual mineral phases. The characteristic “hump” of an amorphous phase in the range from 20 to 40◦ 2θ was observed in FA and in all AWAFA samples. By the XRD patterns of the AAMs obtained by the activation of a solid three-component system, a new crystalline phase, gehlenite, was identified. The efficiency of AAMs in removing cadmium ions from aqueous solutions was tested under various conditions. The highest values of adsorption capacity, 64.76 mg/g (AWAFA6), 67.02 mg/g (AWAFAMK6), and 72.84 mg/gmg/g (AWAMK6), were obtained for materials activated with a 6 M NaOH solution in the alkali activator. The Langmuir adsorption isotherm and pseudo-second kinetic order provided the best fit for all investigated AAMs.
Ključne besede: fly ash, metakaolin, wood ash, adsorption kinetics, cadmium (II)
Objavljeno v DiRROS: 23.05.2024; Ogledov: 1089; Prenosov: 472
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7. Why are the Early Gothic murals in St. Jacob’s Church in Ormož, Slovenia, almost entirely black?Anabelle Križnar, Katja Kavkler, Sabina Dolenec, 2024, izvirni znanstveni članek Povzetek: In St. Jacob’s parish church in Ormož, Slovenia, mural paintings from around 1350–1370 are partially conserved in the northeastern corner of the main nave. They are almost completely black, indicating a large-scale pigment degradation. They were studied as a part of a larger research project aiming to identify materials applied and their possible degradation. First, they were studied in situ, and next, extracted samples of plaster, pigments, and colour layers were analysed by optical microscopy, Raman spectroscopy, FTIR spectroscopy, SEM-EDS, and XRD. Haematite, green earth, malachite, azurite, and tenorite were identified, showing that azurite and perhaps also malachite degraded to black tenorite, probably due to their fine grinding and their application directly on the fresh plaster. The plaster is made with small and large amounts of aggregate with mostly quartz with some impurities, which makes it fragile. The original appearance of these murals was of bright blue and green colours.
Ključne besede: mural painting, medieval painting, Gothic art, St. Jacob's Church, Ormož, Slovenia, pigments, chemical structure, colour degradation, optical microscopy, Raman microspectroscopy, FTIR, XRD
Objavljeno v DiRROS: 17.04.2024; Ogledov: 642; Prenosov: 513
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8. Pitna voda v Mestni občini Ljubljana : pot od vodnega vira do kozarcaTadeja Kosec, Nina Gartner, Brigita Jamnik, Viviana Golja, Alenka Labovič, Lucija Smojver, Sabina Dolenec, Aljoša Šajna, Monika Novak Babič, Nina Gunde-Cimerman, Tinkara Kopar, 2019, strokovna monografija Ključne besede: centralni vodovodni sistem Ljubljana (CVS), pitna voda, materiali v stiku s pitno vodo, vzdrževanje sistemov, preskušanje, kovinski materiali, organski materiali, cementni materiali, mikrobiološki vpliv, certificiranje proizvodov, vodno gospodarstvo, oskrba z vodo
Objavljeno v DiRROS: 08.03.2024; Ogledov: 841; Prenosov: 403
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9. Construction materials for a sustainable future : proceedings of the 2nd International Conference CoMS 2020/212021, zbornik recenziranih znanstvenih prispevkov na mednarodni ali tuji konferenci Povzetek: Zbornik pokriva številne, predvsem tehnične teme, ki so pomembne za trajnostni razvoj gradbenega sektorja, kot ključnega dejavnika pri doseganju ciljev EU za obvladovanje podnebnih sprememb in za prehod v brezogljično družbo. Vsebinsko naslavlja inovacije v gradbenih materialih in tehnologijah, vključno s komponentami za zdravo in udobno bivanje, ter interakcije med materiali in okoljem. Poleg energetske učinkovitosti stavb je v njem zajeto področje širšega razumevanja trajnostnega načrtovanja, gradnje in vzdrževanja stavb ter monitoring, ocenjevanje in modeliranje stavb. Vključuje pa tudi vsebine, ki se nanašajo na krožno gospodarstvo, kot je recikliranje materialov in komponent ter koncepti sanacij stavb, ter na digitalizacijo in avtomatizacijo področja.
Ključne besede: trajnostno gradbeništvo, trajnostna gradnja, gradbeni materiali, tehnologije, energetska učinkovitost, zborniki, elektronske knjige
Objavljeno v DiRROS: 25.01.2024; Ogledov: 1051; Prenosov: 405
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