11. Differential diagnosis between bone metastases and osteomalaciaBranko Zakotnik, Simona Borštnar, Tadeja Movrin, Boris Jančar, Andreja Zidar, 1996, original scientific article Abstract: In oncology the diagnosis of skeletal metastases is a frequent one, in infact so frequent that other diagnoses such as metabolic bone diseases affecting patients with cancer may be overlooked. In our report two cases of osteomalacia referred to an oncologist are presented; in both of them the diagnosis of diffuse bone metastases of unknown origin was suspected. The differential diagnosis is discussed and the importance of bone marrow biopsy using Yamshidi needle for diagnosis of metabolic bone disease is emphasized.
Published in DiRROS: 16.01.2024; Views: 147; Downloads: 36
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13. The microstructure, mechanical and electrochemical properties of 3D printed alloys with reusing powdersMirjam Bajt Leban, Miha Hren, Tadeja Kosec, 2023, original scientific article Abstract: CoCrMo and Ti6Al4V are widely used in medical, dental and 3D printing technology, allowing the accurate fabrication of geometrically complicated structures. In order to reduce the costs of printed objects, the reuse of powder is common daily practice. AQ1 When using 3D printing technology, the direct impact of elevated temperatures and the influence of the laser beam may change the properties of the powder when it is reused, thus affecting the final properties of the printed object. The main aim of the present study was to investigate the impact of reused powder on the mechanical, microstructural and electrochemical properties of 3D printed objects. 3D printed objects fabricated from virgin and reused powder of both alloys were analyzed by metallographic observation, computed tomography, XRD and electrochemical methods. The main finding of the study was that the use of reused powder (recycled 3 times) does not detrimentally affect the mechanical and corrosion integrity of 3D printed CoCr and Ti6Al4V alloys, especially for the purpose of applications in dentistry.
Keywords: additive manufacturing, selective laser melting, virgin powder, reused powder, microtomography
Published in DiRROS: 08.01.2024; Views: 189; Downloads: 86
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14. Efficiency of a corrosion inhibitor on bare, oxidized and real archeological bronze in indoor polluted atmosphere - digital image correlation approachTadeja Kosec, Polonca Ropret, 2021, original scientific article Abstract: A corrosion inhibitor, tolyl methyl imidazole (TMI), was tested in practice and verified in a polluted in-door atmosphere. Special attention was given to its behavior in indoor storage conditions, where volatileorganic pollutants may cause damage to metal artefacts. Prepared samples of bronze and oxidized bronzewere exposed to acetic acid vapors. Raman analysis showed copper acetate and copper nitrate forma-tion. Suppression of corrosion development following the application of tolyl methyl imidazole (TMI) wasobserved. A simple method based on image analysis for corrosion evaluation was specifically developed.The TMI inhibition action was tested on a Roman archeological object and evaluated after exposure toindoor pollutants.
Keywords: bronze, inhibitor, corrosion, Raman
Published in DiRROS: 20.12.2023; Views: 171; Downloads: 96
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15. Corrosion monitoring of steel structure coating degradationBojan Zajec, Mirjam Bajt Leban, Tadeja Kosec, Viljem Kuhar, Andraž Legat, Stanislav Lenart, Karmen Fifer Bizjak, Gavin Kenneth, 2018, original scientific article Abstract: An important aspect regarding the sustainability of steel structures is to ensure the structure is protected from corrosion. A number of surface coatings are availablethat play an important role in protecting these structures. An important part of the management of these structures is reliable and regular inspection along with methods forearly detection of corrosion processes. In this paper, a development and application of sensors for monitoring the steel coating degradation and corrosion damage to steelsubstrate are presented. An encapsulated corrosion kit with integrated EIS sensors and ER probes was developed. To test its efficiency, steel probes were coated withselected coatings in the laboratory and their performance was assessed under various aggressive atmospheres, including; salt, industrial and humid atmosphere.
Keywords: coatings, corrosion, electrochemical impedance spectroscopy, electrical resistance probes, railways, steel structures
Published in DiRROS: 13.12.2023; Views: 163; Downloads: 85
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16. Metode v nuklearni medicini v diagnostiki raka dojkTadeja Movrin, 1998, review article Abstract: Mamografija in ultrazvok sta v svetu in pri nas metodi izbora pri odkrivanju raka dojke. Pri bolnicah z gostimi dojkami, s cistično spremenjenimi, s fibrozno displazijo in nekaterimi drugimi spremembami pa ti dve metodi nista več zanesljivi. Novejše raziskave kažejo, da je izotopna mamografija z 99mTc MIBI (methoxyisobutylisonitrile), ki temelji na biokemičnih in fizioloških osnovah tumorja, dovolj dobra preiskava, da bo ta vrzel zapolnjena.
Published in DiRROS: 24.11.2023; Views: 142; Downloads: 58
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17. Activation and repassivation of stainless steels in artificial brines as a function of pHEmir Mujanović, Bojan Zajec, Tadeja Kosec, Andraž Legat, Stefan Hönig, Gerald Zehethofer, Gregor Mori, 2019, original scientific article Abstract: When planning oil wells with stainless steel components, two possible reasons for depassivation have to be considered-chemical depassivation caused by acidizing jobs and mechanical depassivation caused by various tools and hard particles. The study explores conditions causing chemical activation of investigated steels and circumstances under which repassivation occurs after activation. The main focus of the study is to determine, how quickly various steels can repassivate under different conditions and to find pH values where repassivation will occur after depassivation. The investigated steels were ferritic (martensitic or bainitic) in the cases of 13Cr, 13Cr6Ni2Mo, and 17Cr4Ni2Mo, austenitic in the case of 17Cr12Ni2Mo, and duplex (austenitic and ferritic) in the case of 22Cr5Ni3Mo. Potentiodynamic experiments were employed to obtain electrochemical properties of investigated steels, followed by immersion tests to find ultimate conditions, where the steels still retain their passivity. After obtaining this information, scratch tests were performed to study the repassivation kinetics. It was found that repassivation times are similar for nearly all investigated steels independent of their chemical composition and microstructure.
Keywords: stainless steels, activation, repassivation
Published in DiRROS: 21.11.2023; Views: 231; Downloads: 108
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18. The corrosion properties of steel in pore solutions obtained from alkali‐activated mortarsNina Gartner, Tadeja Kosec, Stéphane Poyet, Andraž Legat, 2023, original scientific article Abstract: Alkali‐activated materials (AAMs) are considered a promising alternative to materials made from ordinary Portland cement (OPC). Other than considering the durability of the material itself, the use of AAMs for reinforced concrete elements also raises the question of steel corrosion processes in these materials, which are still relatively unknown. Three different alkali‐activated mortars were prepared for this study, based on either fly ash, slag, or metakaolin. Pore solutions were then extracted from each mortar and chemically analyzed. Electrochemical techniques were used to study the corrosion of steel in synthetic pore solutions containing varying concentrations of chlorides. In parallel, the same corrosion tests were performed in a generic pore solution representing OPC mortar. It was shown that the chemical composition differed in each pore solution tested, thus affecting the corrosion properties of the steel. The addition of chloride also had a varying effect on the corrosion properties of the steel in each type of pore solution tested. This study provided a basic overview of the corrosion behavior and mechanisms of the various AAM environments in comparison to that of OPC.
Keywords: alkali-aktivated materials, corrosion, electrochemical corrosion techniques, extracted pore solution
Published in DiRROS: 20.11.2023; Views: 235; Downloads: 34
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19. Corrosion properties of aluminized 16Mo3 steelBlaž Karpe, Klara Prijatelj, Milan Bizjak, Tadeja Kosec, 2023, original scientific article Abstract: Chromium-molybdenum steel (16Mo3) is widely used in petroleum, gas, automotive, and construction industries due to its good oxidation resistance and mechanical properties at moderately elevated temperatures. The aim of the research was to evaluate the corrosion susceptibility of 16Mo3 steel in hot rolled and aluminized states. Aluminization was performed by diffusion pack aluminization process at 900°C/2h and 730°C/4h, respectively. Electrochemical corrosion testing included measuring open circuit potential (EOCP), linear polarization resistance (LPR), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) in potassium phosphate buffer (KH2PO4, pH = 7). Optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) were used for surface layer microstructure characterization before and after corrosion tests. It was demonstrated that corrosion resistance of aluminized steel increased substantially. Corrosion properties were related to the structure and properties of intermetallic phase (FeAl, FeAl2 and Fe2Al5) that formed on the surface of 16Mo3 steel.
Keywords: aluminide coatings, aluminized steel, aluminizing, electrochemical corrosion investigation, 16Mo3 steel
Published in DiRROS: 16.11.2023; Views: 301; Downloads: 161
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20. Monitoring the galvanic corrosion of copper–steel coupling in bentonite slurry during the early oxic phase using coupled multielectrode arraysTadeja Kosec, Miha Hren, Klara Prijatelj, Bojan Zajec, Nina Gartner, Andraž Legat, 2023, original scientific article Abstract: In the case of a two-part container for spent nuclear fuel, consisting of an iron-based inner structure with a copper coating, the potential perforation of copper through minor damage may result in intensive galvanic corrosion between copper and steel. The present work focuses on the corrosion of steel galvanically coupled to copper and exposed to a slightly saline environment under oxic conditions. The electrochemical processes on individual electrodes were monitored by coupled multielectrode arrays (CMEAs). The CMEAs were either in contact with groundwater saturated with bentonite or immersed in groundwater only. Very high galvanic corrosion currents were detected between carbon steel and pure copper in the early oxic phase. Additionally, the use of CMEAs further made it possible to monitor the distribution of cathodic currents around the steel electrode, which behaved anodically. Various microscopy and spectroscopy techniques were applied to identify the modes of corrosion and the type of corrosion products present at the end of the period of exposure.
Keywords: copper, steel, bentonite, Aspö groundwater, coupled multi electrode array, electrochemical properties, Raman analysis, corrosion
Published in DiRROS: 16.11.2023; Views: 300; Downloads: 38
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