211. Influence of microwaves in the early stage of alkali activation on the mechanical strength of alkali-activated materialsBarbara Horvat, Majda Pavlin, Vilma Ducman, 2023, original scientific article Abstract: This study focuses on the influence of microwave irradiation dosimetry on alkali-activated slurry in its early stages. The impact on the chemistry and mineralogy along with the mechanical properties were evaluated by changing the power of microwaves and their duration of exposure. This influenced the dissolution of amorphous content, diffusion, and self-assembly into an aluminosilicate network. The precursors used in this study were metakaolin, a non-waste material commonly used in geopolymerisation technology, and local fly ash and ladle furnace slag as secondary materials. Furthermore, they were chemically and mineralogically analysed, and their mixtures with NaOH and Na-water glass provided the optimal ratio of the amount of elements obtained using the pre-calculation approach. However, the potential extra addition of water was experimentally determined to allow complete wetting of the material and solid workability during moulding. Using Fourier-transform infrared spectroscopy, the influence of water was further investigated in alkali-activated slag and fly ash irradiated with microwaves, which resulted in the highest values of mechanical strength in the dosimetry-mapping part of the analysis. In addition to the time dependence of the expected mechanical strength on the ageing of the alkali- activated material, the synthesised material exhibited a significant dependence on the dose of microwave irra- diation, which was different for every precursor as well as every mixture with different chemistries.
Keywords: odpadni material, alkalijska aktivacija, obsevanje z mikrovalovi, mehanska trdnost, waste material, alkali activation, microwave irradiation, mechanical strength
Published in DiRROS: 12.07.2023; Views: 409; Downloads: 301
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212. Using recycled material from the paper industry as a backfill material for retaining walls near railway linesKarmen Fifer Bizjak, Barbara Likar, Stanislav Lenart, 2021, original scientific article Abstract: The construction industry uses a large amount of natural virgin material for different geotechnical structures. In Europe alone, 11 million tonnes of solid waste is generated per year as a result of the production of almost 100 million tonnes of paper. The objective of this research is to develop a new geotechnical composite from residues of the deinking paper industry and to present its practical application, e.g., as a backfill material behind a retaining structure. After different mixtures were tested in a laboratory, the technology was validated by building a pilot retaining wall structure in a landslide region near a railway line. It was confirmed that a composite with 30% deinking sludge and 70% deinking sludge ash had a high enough strength but experienced some deformations before failure. Special attention was paid to the impact of transport, which, due to the time lag between the mixing and installation of the composite, significantly reduced its strength. The pilot retaining wall structure promotes the use of recycled materials with a sustainable design, while adhering to government-mandated measures.
Keywords: paper sludge ash, deinking sludge, paper industry, backfill material, retaining wall
Published in DiRROS: 04.07.2023; Views: 290; Downloads: 179
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213. Valorized deinking paper residue as fill material for geotechnical structuresKarmen Fifer Bizjak, Barbara Likar, Ana Mladenovič, Vesna Zalar Serjun, 2021, original scientific article Abstract: This study introduces a novel geotechnical composite material comprising two types of fill material sourced from the paper industry-deinking paper sludge ash (DPSA) and deinking paper sludge (DPS). Five composites with different DPSA and DPS contents were investigated. Two composites were selected for further analyses. The technology and procedure for composite installation were implemented in field tests. The composites with 80% and 70% DPSA exhibited the elasticity required to withstand minor landslide slip deformations, in addition to achieving sufficiently high values of uniaxial compressive strength. The composites had a low maximum dry density value, which led to fewer settlements in the entire support structure. The enhanced shear characteristics can enable the construction of a thinner retaining wall. The delay between preparation and installation of the composites was further investigated. The field tests confirmed that the composites with 80% and 70% DPSA can be installed on the construction site 4 h and even 24 h after mixing. In 2018, a retaining wall structure with 70% DPSA and 30% DPS was successfully implemented near a railway line using conventional technology as followed-up research to the herein presented study. Results have been derived from work performed in the scope of the H2020 Paperchain project in which novel circular economy models centered on the valorization of the waste streams generated by the pulp and paper industry as secondary raw material for several resource-intensive sectors, including the construction sector, have been developed. Environmental benefits are savings in natural raw materials, reduction of landfill disposal as well as CO2 emission reduction.
Keywords: deinking paper sludge ash, deinking paper sludge, secondary resources, fill material, geotechnical structure, landslide, open access
Published in DiRROS: 04.07.2023; Views: 303; Downloads: 231
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214. Poročilo o preskusu št.: LVG 2023-040 : vzorec št. 2023/00151Maarten De Groot, Zina Devetak, Špela Jagodic, Barbara Piškur, 2023, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Fusarium circinatum, borov smolasti rak, Pinus, bor
Published in DiRROS: 21.06.2023; Views: 304; Downloads: 0 |
215. Poročilo o preskusu št.: LVG 2023-038 : vzorec št. 2023/00179Ana Brglez, Zina Devetak, Barbara Piškur, 2023, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Fusarium circinatum, borov smolasti rak, Pinus, bor
Published in DiRROS: 20.06.2023; Views: 318; Downloads: 0 |
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217. Preparation of façade panels based on alkali-activated waste mineral wool, their characterization and durability aspectsMajda Pavlin, Barbara Horvat, Vilma Ducman, 2022, original scientific article Abstract: Mineral wool is a widely used insulation material and one of the largest components of construction and demolition waste, yet it mainly ends up in landfills. In this work, we explored the potential recycling of waste stone wool in the pilot production of alkali-activated façade panels. The current work shows mechanical properties, SEM-EDS and mercury intrusion porosimetry analyses for three different mix designs used for the preparation of façade panels. They are all composed of waste stone wool and differ in the amount of co-binders (local slag, lime, metakaolin and/or fly ash) selected by the preliminary studies. In this study, co-binders were added to increase early strength and improve the mechanical properties and freeze-thaw resistance. The mechanical properties of each were measured up to 256 days, different durability tests were executed, and, by evaluating the mechanical properties, microstructure and workability of the mortar, the most suitable mix was selected to be used for pilot production. In addition, the leaching test of the selected mixture showed no exceeded toxic trace elements and therefore got classified as non-hazardous waste after its use.
Keywords: alkali activation, waste mineral wool, SEM, XRF, XRD, mechanical strength
Published in DiRROS: 19.06.2023; Views: 358; Downloads: 147
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218. The preparation and characterization of low-temperature foams based on the alkali activation of waste stone woolMajda Pavlin, Barbara Horvat, Mark Češnovar, Vilma Ducman, 2022, original scientific article Abstract: Waste mineral wool represents a huge amount of construction and demolition waste that is still not adequately returned into the value chain but needs to be landfilled. In the present study, waste stone wool (SW) was evaluated for the preparation of alkali-activated foams. For this purpose SW was milled and sieved below 63 μm, then the activator (sodium silicate) and different amounts of foaming agent (hydrogen peroxide, H2O2), varying between 1 wt% and 3 wt%, were added to the slurry and cured in moulds at an elevated temperature (70 ◦ C) for three days. In this way, foamed, highly porous materials were obtained whose density and mechanical properties were influenced by the amount of foaming agent used. The densities obtained ranged between 1.4 and 0.5 g/cm3, with corresponding mechanical properties of between 12.6 and 1.5 MPa and total porosities in the range 37.8–78.6%, respectively. In the most porous samples with the total porosity of 78.6%, a thermal conductivity of 0.092 W/(m∙K) was confirmed. The study confirmed the suitability of waste mineral wool (in our case SW) as a precursor for alkali-activated foams with potential use in the construction sector or other industrial applications.
Keywords: alkali activation, waste mineral wool, mechanical strength, open access, alkalijska aktivacija, odpadna volna, SEM, XRF, XRD, mehanska trdnost, odprti dostop
Published in DiRROS: 19.06.2023; Views: 301; Downloads: 219
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219. Ali visoko maligni B-celični limfomi, dvojni ekspresorji, res potrebujejo intenzivnejšo kemoterapijoLučka Boltežar, Samo Rožman, Gorana Gašljević, Biljana Grčar-Kuzmanov, Barbara Jezeršek Novaković, 2023, published scientific conference contribution Abstract: Velikocelični B limfomi z BCL2 in BCL6 preureditvijo so imenovani "double-hit" oziroma "triplehit" limfomi, z imunohistokemično ekspresijo pa dvojni ekspresorji (DE) in vsi imajo slabšo prognozo od klasičnih velikoceličnih limfomov B. Opravljena je bila študija vseh bolnikov z visoko malignimi B limfomi in difuznim velikoceličnim limfomom B, zdravljenih na Onkološkem inštitutu Ljubljana med leti 2017 in 2021. Večina izmed 154 vključenih bolnikov je bila zdravljenih z R-CHOP terapijo (rituksimab, ciklofosfamid, doksorubicin, vinkristin in prednizon), mediani čas spremljanja bolnikov je bil 22 mesecev. 110 bolnikov (71,4 %) ni imelo ponovitve bolezni v opazovanem obdobju. V primerjavi štirih uporabljenih terapevtskih protokolov v skupini DE nismo našli razlik v preživetju (p < 0,712). Preživetje bolnikov z "double-hit" in "triple-hit" limfomi je bilo, pričakovano, slabo. Naši podatki kažejo, da je velik del bolnikov z DE, zdravljen z R-CHOP in standardno CŽS profilakso, tudi uspešno ozdravljen. Za potrditev naših izsledkov so potrebne večje randomizirane raziskave.
Keywords: limfomi, kemoterapija, onkološko zdravljenje
Published in DiRROS: 16.06.2023; Views: 418; Downloads: 161
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220. Organoidi glioblastoma razkrivajo odpornost na standardno terapijoBernarda Majc, Anamarija Habič, Marta Malavolta, Aleksander Sadikov, Andrej Porčnik, Jernej Mlakar, Tamara Lah Turnšek, Barbara Breznik, Metka Novak, 2023, published scientific conference contribution abstract Keywords: glioblastom, organoidi, standardna terapija, model ex vivo, biologija raka
Published in DiRROS: 16.06.2023; Views: 401; Downloads: 145
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