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21.
Izgradnja lizimetrov za preučevanje izpiranja potencionalno nevarnih snovi iz gradbenih proizvodov
Janez Turk, Janko Urbanc, Ana Mladenovič, Alenka Sešek Pavlin, Primož Oprčkal, Karmen Fifer Bizjak, Barbara Likar, Marko Brodnik, Nina Mali, 2020, izvirni znanstveni članek

Povzetek: Z uporabo recikliranih odpadkov v gradbeništvu nadomeščamo naravne materiale in s tem vzpostavljamo krožno gospodarstvo na lokalnem nivoju. Pomemben vidik je tudi ohranjanje naravnih virov. To je še posebno pereče pri zemeljskih delih (npr. zasipih in nasipih), kjer prihaja do velike porabe materialov. Geotehnični kompoziti iz recikliranih materialov, v primerjavi z naravnimi agregati ali zemljinami, lahko vsebujejo višje celotne koncentracije potencialno nevarnih snovi (težke kovine, klorid, sulfat, fluorid, organska onesnaževala itd.). Pogoj za uporabo takšnih kompozitov je, da so v njih potencialno nevarne snovi imobilizirane in da so zato iz kemijskega vidika trajno inertni. Možni vplivi na okolje, predvsem prenos različnih potencialno nevarnih snovi iz kompozitov v tla oziroma vodonosnik, so običajno ovrednoteni na laboratorijski ravni, medtem ko je njihovo obnašanje v dejanskem okolju slabo proučeno. Zato se pojavljajo zahteve po razvoju občutljivih, zanesljivih in cenovno ter časovno učinkovitih orodij za določitev masnih tokov potencialno nevarnih snovi iz gradbenih proizvodov, na primer geotehničnih kompozitov, pod vplivi različnih okoljskih dejavnikov. V članku predstavljamo postopek vzpostavitve terenskega laboratorija na osnovi sistema "pan" lizimetrov, za zbiranje izcednih voda iz zasipov, ki so bili izdelani iz geotehničnih kompozitov iz recikliranih materialov. Lizimetre smo konstruirali in izvedli tako, da je njihova izgradnja cenovno ugodna, hkrati pa so po svojih dimenzijah dovolj veliki, da reprezentativno odražajo procese v zgrajenih geotehničnih zasipih. Pridobljeni podatki o količini in parametrih izcedne vode bodo služili kot osnova za določanje vodne bilance in za študij imobilizacije potencialno nevarnih snovi v kompozitih. Hkrati bodo uporabljeni kot vhodni podatki za geokemijski numerični model, s katerim bomo simulirali transport potencialno nevarnih snovi, sproščenih iz preučevanih kompozitov, v različnih tipih vodonosnikov (npr. medzrnski in razpoklinski).
Ključne besede: lizimeter, izlužek, okoljski monitoring, geotehnični zasip, odpadki
Objavljeno v DiRROS: 12.09.2023; Ogledov: 244; Prenosov: 110
.pdf Celotno besedilo (2,46 MB)
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22.
Remediation of contaminated soil by red mud and paper ash
Primož Oprčkal, Ana Mladenovič, Nina Zupančič, Janez Ščančar, Radmila Milačič, Vesna Zalar Serjun, 2020, izvirni znanstveni članek

Povzetek: Remediation of contaminated soil can be performed by using various techniques, which must be adequately tailored for each specific case. The aim of this research is to critically evaluate the potential use of red mud and paper ash and a combination of the two as immobilization additives for the remediation of contaminated soil from one of the most polluted sites in Slovenia. The proposed procedure involves the preparation of geotechnical composites made from contaminated soil and mixed with 25 wt% of immobilization additives and an optimal quantity of water to achieve consistency, at which maximum compaction according to the Proctor Compaction Test procedure can be achieved. The results reveal a positive, time-dependent trend for the immobilization of potentially toxic elements in the composite with paper ash, because of the formation of the new hydration products with potentially toxic elements. In a composite containing only red mud, potentially toxic elements were immobilized by sorption mechanisms with no general time-dependent trends. The composite with a combination of additives demonstrates the remediation characteristics of both red mud and paper ash. Using this approach excavated contaminated soil, red mud and paper ash can be successfully recycled in the proposed composites, which can be beneficially used in situ for rehabilitation of contaminated sites. Nevertheless, mobilization of some potentially toxic elements at high pHs may represent a limiting factor and has to be taken into the consideration when a combination of red mud and paper ash is used as immobilization additive.
Ključne besede: red mud, paper ash, contaminated soil, potentially toxic elements, geotechnical composites
Objavljeno v DiRROS: 31.08.2023; Ogledov: 265; Prenosov: 209
.pdf Celotno besedilo (2,28 MB)
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23.
Monitoring the corrosion of steel in concrete exposed to a marine environment
Nina Gartner, Tadeja Kosec, Andraž Legat, 2020, izvirni znanstveni članek

Povzetek: Reinforced concrete structures require continuous monitoring and maintenance to prevent corrosion of the carbon steel reinforcement. In this work, concrete columns with carbon and stainless steel reinforcements were exposed to a real marine environment. In order to monitor the corrosion processes, two types of corrosion probes were embedded in these columns at different height levels. The results from the monitoring of the probes were compared to the actual corrosion damage in the different exposure zones. Electrical resistance (ER) probes and coupled multi-electrodes (CMEs) were shown to be promising methods for long-term corrosion monitoring in concrete. Correlations between the different exposure zones and the corrosion processes of the steel in the concrete were found. Macrocell corrosion properties and the distribution of the separated anodic/cathodic places on the steel in chloride-contaminated concrete were addressed as two of the key issues for understanding the corrosion mechanisms in such environments. The specific advantages and limitations of the tested measuring techniques for long-term corrosion monitoring were also indicated. The results of the measurements and the corrosion damage evaluation clearly confirmed that the tested stainless steels (AISI 304 and AISI 304L) in a chloride-contaminated environment behave significantly better than ordinary carbon steel, with corrosion rates from 110% to 9500% lower in the most severe (tidal) exposure conditions.
Ključne besede: corrosion in concrete, steel reinforcement, long-term exposure, field exposure, electrical resistance (ER) probes, coupled multi-electrodes
Objavljeno v DiRROS: 21.08.2023; Ogledov: 214; Prenosov: 139
.pdf Celotno besedilo (4,42 MB)
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24.
Phase development and hydration kinetics of belite-calcium sulfoaluminate cements at different curing temperatures
Maruša Mrak, Nina Daneu, Sabina Dolenec, 2020, izvirni znanstveni članek

Povzetek: The influence of different curing temperatures on the hydration of belite-calcium sulfoaluminate cement was investigated at 20, 40 and 60 °C. The hydration kinetics and the hydrated phase assemblages were studied by isothermal calorimetry, X-ray powder diffraction, differential thermal analysis and thermogravimetric analysis, as well as field emission scanning electron microscopy. The compressive strength development of the cement pastes was also determined. Results showed that, at early ages, hydration was faster and early compressive strength was higher at elevated temperatures than at ambient temperature. On the other hand, at late ages in cement pastes cured at 60 °C, the amount of ettringite decreased, leading to lower compressive strength, indicating that the degree of hydration was lower at higher temperatures. Moreover, at elevated temperatures prismatic ettringite crystals became smaller due to faster hydration. Other hydration products present were aluminium hydroxide, which is formed together with ettringite from the hydration of calcium sulfoaluminate and gypsum, and C–S–H which precipitates as a main hydration product of belite. Belite hydrated in a lesser amount, especially at 60 °C, when the lowest amount of C–S–H was observed.
Ključne besede: hydration, cement, temperature, belite, calcium sulfoaluminate, open access, hidratacija, cement, temperatura, belit, kalcijev sulfoaluminat
Objavljeno v DiRROS: 04.08.2023; Ogledov: 267; Prenosov: 177
.pdf Celotno besedilo (7,33 MB)
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25.
Priporočila za obravnavo bolnikov s pljučnim rakom
Martina Vrankar, Nina Boc, Izidor Kern, Aleš Rozman, Karmen Stanič, Tomaž Štupnik, Mojca Unk, Maja Ebert Moltara, Vesna Zadnik, Katja Adamič, Jernej Benedik, Marko Bitenc, Jasna But-Hadžić, Anton Crnjac, Marina Čakš, Dominik Časar, Eva Ćirić, Tanja Čufer, Ana Demšar, Rok Devjak, Goran Gačevski, Marta Globočnik Kukovica, Kristina Gornik-Kramberger, Maja Ivanetič Pantar, Marija Ivanović, Urška Janžič, Staša Jelerčič, Veronika Kloboves-Prevodnik, Mile Kovačević, Luka Ležaič, Mateja Marc-Malovrh, Katja Mohorčič, Loredana Mrak, Igor Požek, Nina Turnšek, Bogdan Vidmar, Dušanka Vidovič, Gregor Vlačić, Ana Lina Vodušek, Rok Zbačnik, Ivana Žagar, 2023, strokovni članek

Povzetek: Leta 2019 so bila objavljena Priporočila za obravnavo bolnikov s pljučnim rakom, ki so v slovenski prostor vnesla prepotrebno poenotenje diagnostike in zdravljenja z namenom izboljšanja preživetja bolnikov s pljučnim rakom. Posodobitev Priporočil tri leta po izidu izvirnika prinaša največ novosti v poglavju o sistemskem zdravljenju bolnikov s pljučnim rakom. To kaže na izjemen napredek na področju razumevanja onkogeneze in biologije pljučnega raka ter s tem razvoja novih zdravil. Breme pljučnega raka ostaja veliko, saj je pljučni rak pri nas in v svetu še vedno najpogostejši vzrok smrti zaradi raka. Za vsako peto smrt zaradi raka je odgovoren pljučni rak. Skoraj tretjina bolnikov s pljučnim rakom ne prejme specifičnega onkološkega zdravljenja, bodisi zaradi slabega stanja zmogljivosti, spremljajočih bolezni ali obsega bolezni. Polovica bolnikov ima ob diagnozi razsejano bolezen, zaradi česar izboljšanje preživetja z malimi koraki sledi napredku v zdravljenju bolnikov s pljučnim rakom. Ti podatki nas opominjajo, da se bomo morali za velike premike v obravnavi bolnikov s pljučnim rakom lotiti drugačnih pristopov. Kot najbolj obetavno se ponuja zgodnje odkrivanje bolezni, ko so možnosti ozdravitve pljučnega raka najboljše. Zapisana Priporočila so usmeritev za obravnavo bolnikov s pljučnim rakom. Le s sodobnim multidisciplinarnim pristopom obravnave lahko bolniku ponudimo zdravljenje, ki mu omogoča najboljši izhod prognostično neugodne bolezni.
Ključne besede: pljučni rak, priporočila
Objavljeno v DiRROS: 27.07.2023; Ogledov: 373; Prenosov: 130
.pdf Celotno besedilo (708,18 KB)
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27.
Characterizing steel corrosion in different alkali-activated mortars
Nina Gartner, Miha Hren, Tadeja Kosec, Andraž Legat, 2021, izvirni znanstveni članek

Povzetek: Alkali-activated materials (AAMs) present a promising potential alternative to ordinary Portland cement (OPC). The service life of reinforced concrete structures depends greatly on the corrosion resistance of the steel used for reinforcement. Due to the wide range and diverse properties of AAMs, the corrosion processes of steel in these materials is still relatively unknown. Three different alkali-activated mortar mixes, based on fly ash, slag, or metakaolin, were prepared for this research. An ordinary carbon-steel reinforcing bar was installed in each of the mortar mixes. In order to study the corrosion properties of steel in the selected mortars, the specimens were exposed to a saline solution in wet/dry cycles for 17 weeks, and periodic electrochemical impedance spectroscopy (EIS) measurements were performed. The propagation of corrosion damage on the embedded steel bars was followed using X-ray computed microtomography (XCT). Periodic EIS measurements of the AAMs showed different impedance response in individual AAMs. Moreover, these impedance responses also changed over the time of exposure. Interpretation of the results was based on visual and numerical analysis of the corrosion damages obtained by XCT, which confirmed corrosion damage of varying type and extent on steel bars embedded in the tested AAMs.
Ključne besede: corrosion, alkali-activated mortars, steel reinforcement, electrochemical impedance spectroscopy, X-ray computed microtomography, visual analysis
Objavljeno v DiRROS: 05.07.2023; Ogledov: 334; Prenosov: 157
.pdf Celotno besedilo (7,00 MB)
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28.
Advanced method for efficient functionalization of polymers by intermediate free-radical formation with vacuum-ultraviolet radiation and producing superhydrophilic surfaces
Alenka Vesel, Rok Zaplotnik, Miran Mozetič, Nina Recek, 2023, izvirni znanstveni članek

Povzetek: An efficient approach for tailoring surface properties of polymers is presented, which enables rapid modification leading to superhydrophilic properties. The approach is based on vacuum-ultraviolet radiation (VUV) pretreatment of the surface to create reactive dangling bonds. This step is followed by a second treatment using neutral oxygen atoms that react with the dangling bonds and form functional groups. The beneficial effect of VUV pretreatment for enhanced functionalization was clearly demonstrated by comparing VUV pretreatment in plasmas created in different gases, i.e., hydrogen, nitrogen, and oxygen, which differ in the intensity of VUV/UV radiation. The emission intensity of VUV radiation for all gases was measured by vacuum ultraviolet spectroscopy. It was shown that VUV has a strong influence on the treatment time and final surface wettability. A superhydrophilic surface was obtained only if using VUV pretreatment. Furthermore, the treatment time was significantly reduced to only a second of treatment. These findings show that such an approach may be used to enhance the surface reaction efficiency for further grafting of chemical groups.
Ključne besede: plasma treatment, vacuum-ultraviolet radiation treatment, surface functionalization, polymer polyvinyl chloride, vacuum-ultraviolet spectroscopy, vacuum-ultraviolet photons
Objavljeno v DiRROS: 06.06.2023; Ogledov: 327; Prenosov: 170
.pdf Celotno besedilo (4,42 MB)
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29.
Kirurško zdravljenje visoko rizičnega raka telesa maternice
Nina Kovačević, 2023, objavljeni znanstveni prispevek na konferenci

Povzetek: Rak materničnega telesa je najpogostejši ginekološki rak in v Sloveniji vsako leto odkrijemo približno 350 novih primerov. Večino rakov materničnega telesa predstavlja rak endometrija, ki ga delimo v dve skupini, in sicer estrogensko odvisni in estrogensko neodvisni rak endometrija. Zdravljenje je v prvi vrsti kirurško, obseg operativnega posega je določen glede verjetnosti ponovitve. Kirurškemu zdravljenju je lahko dodano obsevanje, sistemska terapija ali kombinacija obojega.
Ključne besede: rak maternice, ginekološki raki, ginekološka onkologija
Objavljeno v DiRROS: 30.05.2023; Ogledov: 307; Prenosov: 133
.pdf Celotno besedilo (267,63 KB)
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30.
Application of electrochemical methods for studying steel corrosion in alkali-activated materials
Shishir Mundra, Gabriel Samson, Giulia Masi, Rebecca Achenbach, David M. Bastidas, Susana Bernal, Maria Chiara Bignozzi, Maria Criado, Martin Cyr, Nina Gartner, Stefanie von Greve‐Dierfeld, Andraž Legat, Nikoonasab Ali, John L. Provis, Michael Raupach, Gregor J. G. Gluth, 2023, izvirni znanstveni članek

Povzetek: Alkali‐activated materials (AAMs) are binders that can complement and partially substitute the current use of conventional cement. However, the present knowledge about how AAMs protect steel reinforcement in concrete elements is incomplete, and uncertainties exist regarding the application of electrochemical methods to investigate this issue. The present review by EFC WP11‐Task Force ‘Corrosion of steel in alkali‐activated materials’ demonstrates that important differences exist between AAMs and Portland cement, and between different classes of AAMs, which are mainly caused by differing pore solution compositions, and which affect the outcomes of electrochemical measurements. The high sulfide concentrations in blast furnace slag‐based AAMs lead to distinct anodic polarisation curves, unusually low open circuit potentials, and low polarisation resistances, which might be incorrectly interpreted as indicating active corrosion of steel reinforcement. No systematic study of the influence of the steel–concrete interface on the susceptibility of steel to corrosion in AAMs is available. Less common electrochemical methods present an opportunity for future progress in the field.
Ključne besede: alkali-aktivated materials, alkali‐activated materials, anodic/cathodic polarisation, concrete, linear polarisation resistance, open circuit potential, reinforcement corrosion, resistivity
Objavljeno v DiRROS: 29.05.2023; Ogledov: 266; Prenosov: 109
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