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22. Ultra-high strenght TWIP steel with high chromium contentPavel Podaný, Tomáš Studecký, Tomas Gregor, Radek Prochazka, Aleksandra Kocijan, 2023, original scientific article Abstract: A new ultra-high strength steel with a fully austenitic microstructure and twinning-induced plasticity (TWIP) effect has been developed. TWIP effect gives this steel a good combination of high strength of over 1000 MPa and ductility of over 35%. This new steel has a high chromium content, which increases its corrosion resistance. By combining cold rolling and annealing, the steel has achieved a very fine austenitic microstructure with an average grain diameter of 2.85 µm. This steel could be used for structural applications or components that need to withstand high levels of stress, deformation and corrosion environment.
Keywords: TWIP steels, corrosion resistance, microstructure, tensile strength, plasticity
Published in DiRROS: 31.01.2024; Views: 196; Downloads: 78
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23. Improving the surface properties of additive-manufactured Inconel 625 by plasma nitridingDanijela Anica Skobir Balantič, Črtomir Donik, Bojan Podgornik, Aleksandra Kocijan, Matjaž Godec, 2023, original scientific article Abstract: As a surface-hardening technique, plasma nitriding is a common procedure for improving the properties of
conventional Ni-based alloys. The diffusion of nitrogen hardens a layer on the surface of the alloy, leading to
better wear resistance and a higher coefficient of friction, as well as a higher surface hardness. This study reports
the effect of plasma nitriding on additive-manufactured (AM) Inconel 625 (IN625) compared to its conventional
manufactured and nitrided counterparts. The samples produced with the laser powder-bed fusion (LPBF) process
were subsequently plasma nitrided in the as-built condition, stress-relief annealed at 870 °C and solution treated
at 1050 °C. The plasma nitridings were carried out at 430 °C and 500 °C for 15 h. The growth kinetics of the
nitride layer of the AM samples depends on the prior heat treatments and is faster in the as-built state due to the
specific cellular structure. The lower nitriding temperature leads to the formation of expanded austenite in the
nitride layer, while at the higher nitriding temperature, the expanded austenite decomposes and CrN precipitation
occurs. The XRD and SEM analyses confirmed the presence of two layers: the surface layer and the
diffusion layer beneath. The lower nitriding temperature caused the formation of expanded austenite or a
combination of expanded austenite and CrN. The higher nitriding temperature led to the decomposition of the
expanded austenite and to the formation/precipitation of CrN. The higher nitriding temperature also decreased
the corrosion resistance slightly due to the increased number of precipitated Cr-nitrides. On the other hand, the
wear resistance was significantly improved after plasma nitriding and was much less influenced by the nitriding
temperature.
Keywords: additive manufacturing, powder-bed fusion, plasma nitriding, expanded austenite, wear and corrosion resistance, Ni-based alloy
Published in DiRROS: 31.01.2024; Views: 178; Downloads: 77
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24. Monitoring of species’ genetic diversity in Europe varies greatly and overlooks potential climate change impactsPeter Pearman, Olivier Broennimann, Tsipe Aavik, Tamer Albayrak, Paulo Célio Alves, Filipos Aravanopoulos, Laura Bertola, Aleksandra Biedrzycka, Elena Bužan, Vlatka Čubrić Čurik, Katja Kavčič Sonnenschein, Marjana Westergren, 2024, original scientific article Abstract: Genetic monitoring of populations currently attracts interest in the context of the Convention on Biological Diversity but needs long-term planning and investments. However, genetic diversity has been largely neglected in biodiversity monitoring, and when addressed, it is treated separately, detached from other conservation issues, such as habitat alteration due to climate change. We report an accounting of efforts to monitor population genetic diversity in Europe (genetic monitoring effort, GME), the evaluation of which can help guide future capacity building and collaboration towards areas most in need of expanded monitoring. Overlaying GME with areas where the ranges of selected species of conservation interest approach current and future climate niche limits helps identify whether GME coincides with anticipated climate change effects on biodiversity. Our analysis suggests that country area, financial resources and conservation policy influence GME, high values of which only partially match species’ joint patterns of limits to suitable climatic conditions. Populations at trailing climatic niche margins probably hold genetic diversity that is important for adaptation to changing climate. Our results illuminate the need in Europe for expanded investment in genetic monitoring across climate gradients occupied by focal species, a need arguably greatest in southeastern European countries. This need could be met in part by expanding the European Union’s Birds and Habitats Directives to fully address the conservation and monitoring of genetic diversity.
Keywords: genetics, monitoring, population genetic diversity, Europe
Published in DiRROS: 22.01.2024; Views: 210; Downloads: 90
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25. Phase II study of fluorouracil, leucovorin and interferon alpha-2a in patients with advanced colon cancerBorut Štabuc, Aleksandra Markovič, Erik Brecelj, Samir Bešlija, Tomaž-Edvard Cizej, 1998, original scientific article Abstract: Based on in viro studies that have demonstrated synergy between fluorouracil (5-FU) and leucovorin (LV) as well as between 5-FU and recombinant alpha-2a interferon (IFN) against colon cancer cell lines a phase II study was carried out to evaluate the toxicity and clinical activity of 5-FU modulated with LV and IFN in patients with metastatic colon cancer. Twenty-two chemotherapy naive patients with measurable metastases of colon cancer have been treated with daily doses of 5-FU 600 mg/m2 in 6-hr intravenous infusion, and of LV 20 mg/m2 intravenously and IFN 6 MU subcutaneously, for 5 days every 4 weeks. Median age was 60 years, median PS (ECOG) was 1 (range 0-2). Liver, soft tissue and lung metastases were found in 12, 5 and 8 patients, respectively. Nineteen patients had a single metastatic site, two double, whereas one had more than two metastatic sites. Patients had 2-9 (mean 5) cycles of treatment.Objective response was observed in 7 patients (32%), and stable disease in 7 patients (32%). Overall median survival was 12.5 months, and for responders 14.4 months. Responses were generally short and median time for progression was 5.5 months. The most frequent adverse reactions were flu-like syndrome (50%), nausea/vomiting (36%), diarhoea (13Č), stomatitis (27%) and leucopenia (13%). This regimen of 5-FU with LV and IFN administration does notappear to be superior to previously published shedules of 5-FU with IFN or 5-FU with LV.
Published in DiRROS: 19.01.2024; Views: 158; Downloads: 43
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27. Deformable polyurethane joints and fibre grids for resilient seismic performance of reinforced concrete frames with orthoblock brick infillsTheodoros Rousakis, Alper Ilki, Arkadiusz Kwiecień, Alberto Viskovic, Matija Gams, Petra Triller, Bahman Ghiassi, Andrea Benedetti, Zoran Rakicevic, Camilla Colla, Omer Faruk Halici, BogusŁaw Zając, Łukasz Hojdys, Piotr Krajewski, Fabio Rizzo, Vachan Vanian, Anastasios Sapalidis, Efthimia Papadouli, Aleksandra Bogdanovic, 2020, original scientific article Abstract: The behaviour of reinforced concrete frames with masonry wall infills is influenced a lot by the stiffness and strength difference between the frame and the infill, causing early detrimental damage to the infill or to the critical concrete columns. The paper reports the results from shake table seismic tests on a full-scale reinforced concrete (RC) frame building with modified hollow clay block (orthoblock brick) infill walls, within INMASPOL SERA Horizon 2020 project. The building received innovative resilient protection using Polyurethane Flexible Joints (PUFJs) made of polyurethane resin (PU), applied at the frame-infill interface in different schemes. Further, PUs were used for bonding of glass fibre grids to the weak masonry substrate to form Fibre Reinforced Polyurethanes (FRPUs) as an emergency repair intervention. The test results showed enhancement in the in-plane and out-of-plane infill performance under seismic excitations. The results confirmed remarkable delay of significant infill damages at very high RC frame inter-story drifts as a consequence of the use of PUFJs. Further, the PUFJ protection enabled the resilient repair of the infill even after very high inter-story drift of the structure up to 3.7%. The applied glass FRPU system efficiently protected the damaged infills against collapse under out-of-plane excitation while they restored large part of their in-plane stiffness.
Keywords: polyurethane, flexible joint, RC column, brick infill, shake table, resilience
Published in DiRROS: 05.09.2023; Views: 291; Downloads: 120
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28. Izzivi medgeneracijskega vodenja v zdravstveni negiAleksandra Grbič, 2023, published scientific conference contribution Abstract: Današnja večgeneracijska delovna sila v zdravstveni negi predstavlja edinstvene izzive vodenja. Namen raziskave je prikazati medgeneracijske razlike različnih generacij v zdravstveni negi in vodstvenih "iztočnic", ki bodo vodje usmerjale pri optimalnih strategijah vodenja različnih generacij. Uporabili smo analizo in sintezo pregleda dokazov iz zbirke podatkov CINAHL, PubMed in WEB OF SCIENCE . Ključne iskalne besedne zveze so bile: "nurse", "generation", "multigenerational", "relationship", "teamwork", "leadership". Omejitveni kriteriji iskanja so bili: obdobje 2018 do 2023, celotno besedilo člankov v angleščini. Začetna merila je izpolnjevalo 130 zadetkov, v končno analizo jih je bilo vključenih 9. Rezultati so pokazali, da lahko vodilne medicinske sestre s poznavanjem in razumevanjem ključnih razlik posameznih generacij oblikujejo močnejše time v zdravstveni negi. Razumevanje različnih generacijskih skupin lahko vodjem v zdravstveni negi omogoči razmislek o tem, kaj poganja, motivira ali ovira medicinske sestre različnih generacij. Zaposlovanje in ohranjanje delovne sile, ki jo vse bolj sestavljajo medicinske sestre iz več generacijskih skupin, je izziv, ki ga je mogoče rešiti z globljim razumevanjem vsake od splošno opredeljenih generacijskih skupin
Keywords: medicinske sestre, timsko delo, vodenje
Published in DiRROS: 25.07.2023; Views: 442; Downloads: 103
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29. Hodgkinov limfom : vodnik za bolnikeBarbara Jezeršek Novaković, Samo Zver, Metka Zajc, Aleksandra Grbič, Andreja Cirila Škufca Smrdel, Eda Vrtačnik-Bokal, Vesna Šalamun, Nina Kovačević, Lorna Zadravec-Zaletel, Matej Pečovnik, 2022, not set Keywords: rak (medicina), krvotvorne matične celice, transplantacija, psihološka pomoč, plodnost, hormonsko nadomestno zdravljenje
Published in DiRROS: 24.07.2023; Views: 353; Downloads: 85
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30. Effect of laser texturing pattern on Ti6Al4Vtribocorrosion in a physiological solutionMarjetka Conradi, Tadeja Kosec, Bojan Podgornik, Aleksandra Kocijan, Janez Kovač, Damjan Klobčar, 2022, original scientific article Abstract: Laser texturing is a process that alters a material’s surface properties by modifying its morphology, which can improve properties like adherence, wettability, thermal and electrical conductivity and friction. Here, the effect of laser texturing was studied on an alpha-beta titanium alloy (Ti6Al4V) biomedical material. Two types of patterned surfaces, cross-hatch with varying scan-line separations, Dx = 100, 180 and 280 μm and dimples of 200 μm size, were prepared on the surface of alpha-beta titanium alloy by laser technology. Prepared samples were characterised for their surface properties, such as corrosion, wear-induced corrosion, friction and wettability. Electrochemical and tribocorrosion properties in a physiological solution were studied on the samples with different texture densities of cross-hatch pattern and dimples and compared to the as-received alpha-beta titanium alloy surface. Corrosion rate decreased for laser-textured samples, especially for cross-hatch texture (down to 1 μm/year for Dx = 180 μm) when compared to the as-received alpha-beta titanium alloy surface due to the changed laser-induced surface film and wetting properties. Friction coefficient slightly decreased for all laser-textured surfaces, most noticeably for cross-hatch patterns, from 0.38 (as-received) down to 0.34 (Dx = 180 and 280 μm). The main contribution to total wear in physiological solution increased due to the mechanical wear, which is governed by the removal of the surface oxide layer induced by laser texturing.
Keywords: TiAIV, laser texturing, tribocorrosion, open access
Published in DiRROS: 17.05.2023; Views: 286; Downloads: 116
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