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33. Rotational dynamics of a protein under shear flow studied by the eckart frame formalismPetra Papež, Franci Merzel, Matej Praprotnik, 2023, izvirni znanstveni članek Ključne besede: energy, kinetics, molecules, protein structure, rotational dynamics, molecules, protein structure, rotational dynamics
Objavljeno v DiRROS: 06.09.2023; Ogledov: 293; Prenosov: 164
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34. Vpliv vpetosti med preiskavo obnašanja nearmiranih zidov pri potresni obtežbiPetra Triller, Matija Gams, Miha Tomaževič, 2020, izvirni znanstveni članek Povzetek: V prispevku so predstavljene obsežne eksperimentalne raziskave obnašanja večetažnih zidanih strižnih sten z odprtinami pri potresni obtežbi. Preiskali smo odziv 3-etažnega preizkušanca v naravnem merilu na potresno obtežbo, s katero smo preučevali odziv tipične 5-etažne zidane stavbe, grajene na območju Slovenije in njene širše okolice v času pred letom 1964 (pred prvimi potresni predpisi). Vzporedno smo opravili osem cikličnih strižnih preiskav posameznih zidov pri štirih tipih robnih pogojev. Z analizo rezultatov obsežnih meritev sil in deformacij na površini večetažnih strižnih sten smo ovrednotili vpliv vertikalnih in horizontalnih elementov strižne stene na posamezni slop ter iskali najustreznejši tip robnih pogojev za simulacijo potresnega odziva v preiskavi posameznega zidnega slopa.
Ključne besede: nearmirano zidovje, ciklične strižne preiskave, opečni votlak, preiskava v naravnem merilu, optični sistem za merjenje deformacij
Objavljeno v DiRROS: 05.09.2023; Ogledov: 236; Prenosov: 87
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35. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: polyurethane, flexible joint, RC column, brick infill, shake table, resilience
Objavljeno v DiRROS: 05.09.2023; Ogledov: 291; Prenosov: 120
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36. Chemical recycling of flexible polyurethane foams by aminolysis to recover high-quality polyolsMaja Grdadolnik, Blaž Zdovc, Ana Drinčić, Özgün Can Önder, Petra Utroša, Susana Garcia Ramos, Enrique Dominguez Ramos, David Pahovnik, Ema Žagar, 2023, izvirni znanstveni članek Objavljeno v DiRROS: 28.08.2023; Ogledov: 314; Prenosov: 153
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37. Tribocorrosive study of new and in vivo exposed nickel titanium and stainless steel orthodontic archwiresTadeja Kosec, Petra Močnik, Uroš Mezeg, Andraž Legat, Maja Ovsenik, Monika Jenko, John T. Grant, Jasmina Primožič, 2020, izvirni znanstveni članek Povzetek: The surface, corrosion and wear properties of new and in vivo exposed nickel titanium (NiTi) and stainless steel (SS) archwires used in orthodontic treatment were investigated. Electrochemical and tribo-electrochemical tests in artificial saliva were performed in order to define corrosion properties and to estimate wear rate of new and in vivo exposed NiTi and SS archwires. The surface chemical analysis of the passive film on the NiTi and SS archwires before and after tribocorrosion tests was performed by Auger Electron Spectroscopy (AES). In vivo exposed NiTi and SS archwires had better electrochemical properties than new archwires due to the protective nature of oral deposits. Total wear and coefficients of friction were higher among in vivo exposed archwires and higher in NiTi archwires in comparison to SS archwires. The estimated thickness of the TiO2 passive film on as-received NiTi is 8 nm, while the passive Cr2O3 film on as-received SS is just 1–2 nm. On in vivo exposed NiTi archwire, a 60–80 nm thick organic film/dental plaque was observed, and on SS, it was thinner, at about 60 nm. This research shows the importance of combining AES with electrochemical testing, to characterize tribocorrosive properties of NiTi and SS orthodontic archwires.
Ključne besede: archwires, NiTi, stainless steel, wear
Objavljeno v DiRROS: 24.08.2023; Ogledov: 264; Prenosov: 113
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38. Effect of the microstructural properties of copper on corrosion performanceTadeja Kosec, Jure Voglar, Petra Močnik, Andraž Legat, 2021, izvirni znanstveni članek Povzetek: The aim of the study was to define the influence of microstructural properties on the electrochemical properties of copper in four different forms: copper in sheet form, copper doped with phosphorus, electroplated copper and copper wire. Open circuit potential and polarization resistance measurements were carried out in order to determine the electrochemical properties and corrosion rates of copper in 0.1 M NaCl solution in oxic conditions at ambient temperature. Statistical evaluation of the electrochemical data was performed in order to differentiate between the various forms of copper samples. Microstructural and electrochemical investigations were combined with electron microscopy and Raman analysis of the corrosion products after immersion of the copper samples in a 0.1 M NaCl solution for 30 days. The various morphologies of copper corrosion products were identified and analyzed by Raman spectroscopy for the various forms of copper.
Ključne besede: copper, microstructura, corrosion, Raman
Objavljeno v DiRROS: 19.07.2023; Ogledov: 293; Prenosov: 141
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39. Pitting corrosion on highly alloyed stainless steels in dilute sulphuric acid containing sodium chlorideElina Huttunen-Saarivirta, Elisa Isotahdon, Zaiqing Que, M. Lindgren, Ahmad Mardoukhi, Jean-Baptiste Jorcin, Petra Močnik, Tadeja Kosec, Yassine El Ouazari, Sukanya Hägg Mameng, Lena Wegrelius, 2023, izvirni znanstveni članek Povzetek: Stainless steels are widely used in industrial assets and equipment. Despite their good corrosion resistance under a wide range of operating conditions, there is the possibility of pitting corrosion in the presence of chlorides. However, very few studies have identified the safe operating conditions for various high-alloyed stainless steel grades by comparing their pitting susceptibility. In this research, the susceptibility to pitting attack of five stainless steels with austenitic and duplex microstructures was examined in dilute sulphuric acid solution with varying amounts of NaCl at the temperatures of 50, 90 and 130◦C. Based on potentiodynamic polarization scans, none of the test materials underwent pitting corrosion at 50◦C, but differences in susceptibility to pitting attack were clear between the test materials and NaCl concentrations at the temperature of 90◦C, and further tem- perature increase facilitated uniform corrosion. 28-day immersion tests at 90◦ C confirmed the pitting suscepti- bility of duplex grades 1.4662 (PREN 33) and 1.4462 (PREN 35) in the presence of at least 2000 mg/L NaCl, but not the susceptibility of a corresponding austenitic grade 1.4539 (PREN 34). The grades 1.4547 (PREN 43) and 1.4410 (PREN 44) were not susceptible to pitting corrosion under any of the studied conditions. The results from materials microstructural and electrochemical characterization are presented and discussed in this paper.
Ključne besede: stainless steel, austenitic stainless steel, duplex stainless steel, pitting atttack
Objavljeno v DiRROS: 12.07.2023; Ogledov: 303; Prenosov: 380
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40. Engineered combinatorial cell device for wound healing and bone regenerationLucija Kadunc, Duško Lainšček, Rok Gašperšič, Petra Sušjan, Uroš Kovačič, Miha Butinar, Boris Turk, Roman Jerala, Iva Hafner Bratkovič, 2023, izvirni znanstveni članek Povzetek: Growth factors are the key regulators that promote tissue regeneration and healing processes. While the effects of individual growth factors are well documented, a combination of multiple secreted growth factors underlies stem cell–mediated regeneration. To avoid the potential dangers and laborintensive individual approach of stem cell therapy while maintaining their regeneration-promoting effects based on multiple secreted growth factors, we engineered a “mix-and-match” combinatorial platform based on a library of cell lines producing growth factors. Treatment with a combination of growth factors secreted by engineered mammalian cells was more efficient than with individual growth factors or even stem cell–conditioned medium in a gap closure assay. Furthermore, we implemented in a mouse model a device for allogenic cell therapy for an in situ production of growth factors, where it improved cutaneous wound healing. Augmented bone regeneration was achieved on calvarial bone defects in rats treated with a cell device secreting IGF, FGF, PDGF, TGF-β, and VEGF. In both in vivo models, the systemic concentration of secreted factors was negligible, demonstrating the local effect of the regeneration device. Finally, we introduced a genetic switch that enables temporal control over combinations of trophic factors released at different stages of regeneration mimicking the maturation of natural wound healing to improve therapy and prevent scar formation.
Ključne besede: wound healing, bone regeneration, growth factors
Objavljeno v DiRROS: 01.06.2023; Ogledov: 488; Prenosov: 191
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