91. Raman microspectroscopy of garnets from Sfibulae from the archaeological site Lajh (Slovenia)Saša Kos, Matej Dolenec, Judita Lux, Sabina Dolenec, 2020, original scientific article Abstract: Garnets (19 pieces) of Late Antique S-fibulae from the archaeological site at Lajh-Kranj (Slovenia) were analysed with Raman microspectroscopy to obtain their mineral characteristic, including inclusion assemblage. Most garnets were determined as almandines Type I of pyralspite solid solution series; however, three garnets showed a higher Mg, Mn and Ca contents and were determined as almandines Type II. Most significant Raman bands were determined in the range of 169–173 cm−1 (T(X2+)), 346–352 cm−1 (R(SiO4)), 557–559 cm−1 (ν2), 633–637 cm−1 (ν4), 917–919 cm−1 (ν1), and 1042–1045 cm−1 (ν3). Shifting of certain Raman bands toward higher frequencies was the result of an increase of the Mg content in the garnet composition, which also indicates the presence of pyrope end member in solid garnet solutions. Inclusions of apatite, quartz, mica, magnetite, ilmenite, as well as inclusions with pleochroic or radiation halo and tension fissures (zircon), were found in most of the garnets. Rutile and sillimanite were found only in garnets with the highest pyrope content. Spherical inclusions were also observed in two garnets, which may indicate the presence of melt or gas residues. The determined inclusion assemblage indicates the formation of garnets during medium- to high-grade metamorphism of amphibolite or granulite facies. According to earlier investigations of the garnets from Late Antique jewellery, the investigated garnets are believed to originate from India.
Keywords: garnets, inclusions, Sfibulae, Late Antiquity, provenance, Raman microspectroscopy, XRF spectroscopy
Published in DiRROS: 20.12.2023; Views: 173; Downloads: 146
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92. Antibacterial effect of polymethyl methacrylate resin base containing TiO2 nanoparticlesAnamarija Zore, Anže Abram, Aleksander Učakar, Ivo Godina, Franc Rojko, Roman Štukelj, Andrijana Sever Škapin, Rajko Vidrih, Olivera Dolić, Valentina Veselinović, Klemen Bohinc, 2022, original scientific article Abstract: Restorations in dentistry must reproduce the aspect of the patient’s natural teeth and require non-toxicity, biocompatibility, and good mechanical properties in order to last longer. Restorations are permanently in contact with microbes that can adhere to and form biofilms. The purpose of this study was to determine the adhesion extent of Streptococcus mutans to polymethyl methacrylate (PMMA) resin base containing TiO2 nanoparticles. To understand the adhesion of Streptococcus mutans on the modified resin-based surfaces, the following surface properties were measured: the roughness, contact angle, zeta potential and CIE color parameters. Evaluation of tensile stress performance in TiO2 modified PMMA showed that the maximum tensile stress of the modified PMMA resin decreases with an increasing amount of TiO2 nanoparticles. The increasing amount of TiO2 decreases the roughness and causes contact angles in the border between hydrophilic and hydrophobic surfaces. All the studied surfaces are negatively charged and added TiO2 tends to increase the zeta potential. The addition of TiO2 nanoparticles increases the lightness and decreases the intensity of the red and yellow color. The increasing addition of TiO2 nanoparticles into PMMA increases the morphological change of bacterial cells.
Keywords: bacterial adhesion, Streptococcus mutans, polymethyl methacrylate resin, TiO2, surface properties
Published in DiRROS: 20.12.2023; Views: 169; Downloads: 86
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93. 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: 188; Downloads: 108
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94. Analysis of loading profile effect on testing machine calibration resultsMiha Hiti, 2021, original scientific article Abstract: The paper presents an evaluation of the loading profile effect on the testing machine calibration. First, a 20 kN force transducer was calibrated in a force calibration machine. This transducer was then used for a number of calibration runs in a 600 kN material testing machine where the time step interval of the same loading profile was varied from 120 s to 0 s. Results show good agreement for most of the range but highlight an increasing error due to synchronization and filtering issues in measured signals when approaching very short step intervals and continuous loading.
Keywords: force calibration, loading profile, measurement uncertainty, continuous loading
Published in DiRROS: 20.12.2023; Views: 171; Downloads: 97
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95. Compensation of synchronization error effect in testing machine calibrationMiha Hiti, 2021, original scientific article Abstract: The paper presents an evaluation of synchronization issues when performing material testing machine calibration using continuous loading. A procedure for the compensation of a rangewide error in calibrated force values is proposed based on a correction factor determined from static and transient errors difference at a chosen force step. The procedure was applied for a calibration of a testing machine with a 20 kN force transducer and 200 N/s to 2000 N/s loading rates. The results show good performance of the compensation technique, reducing calibration errors to below 1% in non-synchronized signals even under unknown filter and delay setting.
Keywords: force calibration, loading profile, measurement uncertainty, continuous loading
Published in DiRROS: 20.12.2023; Views: 155; Downloads: 79
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96. Enhancing circular business model implementation in pulp and paper industry (PPI) : a phase-based implementation guide to waste valorisation strategiesaAmaia Sopelana, Asier Oleaga, Juan José Cepriá, Karmen Fifer Bizjak, Helena Paiva, Francisco-Javier Rios-Davila, Adriana H. Martinez, Antonio Cañas, 2023, original scientific article Abstract: Innovation in the circular economy (CE) and the deployment of effective circular business models (CBM) have attracted significant attention in times of growing natural resource scarcity. Despite this widespread interest, significant challenges remain between theoretical innovations and effective CBM implementation in any industrial sector where companies pursue cost-saving opportunities through waste valorisation strategies. Since current methods mislead in terms of the real limitations to designing feasible novel products and services under a circular economy, this study proposes exploring determinants underpinning the organisational resilience of CBMs under a resource efficiency strategy through three case studies. As a result of a co-creation process, the implementation of a CBM framework was built upon empirical data and, thence, a phase-based implementation guide was laid out to assist companies in designing and implementing innovative CBM dealing with the complexity of innovative waste valorisation strategies between the PPI and construction sectors. Relevant findings on managerial and policy recommendations encountered along the demo stage are provided in this paper favouring an effective implementation of CE strategies: the role of technological and non-technological aspects within the CBM, the perspective of the ecosystem and its value proposition, and specific guidelines for the different phases of CBM life cycle.
Keywords: circular business models (CBMs), resource recovery, waste valorisation, strategic management, pulp and paper industry (PPI), construction sector
Published in DiRROS: 13.12.2023; Views: 193; Downloads: 91
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97. 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: 185; Downloads: 99
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98. Potresni odziv večetažnih strižnih zidanih sten in učinek utrjevanja s kompozitnimi oblogamiPetra Triller, Miha Tomaževič, Matija Gams, 2018, original scientific article Abstract: večetažnih sten, sezidanih iz modularnih zidakov, s poudarkom na opazovanju mehanizmov odziva in porušitve, ki se razvijejo v večetažnih stenah z odprtinami. Druga tema je osredotočena na raziskave utrjevanja takšnega zidovja z malto, armirano z mrežicami iz steklenih vlaken. Za raziskave smo na Zavodu za gradbeništvo Slovenije zgradili in preiskali posamezne zidove in večji trietažni preizkušanec v naravni velikosti. V cikličnem strigu pri konstantnem tlaku smo preizkusili več referenčnih in utrjenih zidov ter trietažni model dimenzij 4 x 4 m v tlorisu in višine 6,7 m. Trietažni model smo najprej obremenili do večjih, a popravljivih poškodb. Zatem smo poškodovani preizkušanec utrdili s kompozitnimi oblogami iz malte, armirane s steklenimi vlakni (GFRP), ter ga ponovno preiskali, tokrat skoraj do porušitve. V obeh primerih je bil odziv modela na vodoravno obtežbo s t. i. etažnim mehanizmom, pri katerem se večina poškodb skoncentrira v zidovih najšibkejše etaže. V zidovih smo opazili tipične strižne poškodbe z diagonalnimi razpokami. Potresno obnašanje posameznih zidov je bilo zelo podobno odzivu zidnih slopov večetažnega preizkušanca. Rezultati kažejo, da je mogoče z ustreznim načinom utrjevanja zidov doseči občutno izboljšanje potresnega obnašanja.
Keywords: nearmirano zidovje, laboratorijske preiskave, ciklične strižne preiskave, GFRP-kompoziti, utrjevanje
Published in DiRROS: 13.12.2023; Views: 194; Downloads: 79
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99. Polypropylene blends with m-EPR copolymers : mechanical and rheological propertiesIztok Švab, Anđela Pustak, Matjaž Denac, Andrijana Sever Škapin, Mirela Leskovac, Vojko Musil, Ivan Šmit, 2018, original scientific article Abstract: The effects of two metallocene ethylene-propylene-based elastomers (m-EPR1 and m-EPR2) differing in molecular mass and viscosity on mechanical, rheological and interfacial properties were compared. The m-EPR elastomers were added to iPP in 2.5, 5, 10, 15, and 20 vol.%. Torque values, elongation at break and impact strength measured of the iPP/m-EPR1 blends were higher than the iPP/m-EPR2 blends due to higher molten viscosity of m-EPR1 than m-EPR2 copolymer. Slight differences in Young moduli as well as in tensile strength at yield and at break might indicate that tensile properties of iPP/m-EPR blends were not significantly affected by difference in viscosity or molecular mass, miscibility and spherulite size. Optimization diagrams indicated the metallocene m-EPR copolymers are efficient impact modifiers for polypropylene and showed good balancing of mechanical properties in iPP/m-EPR blends.
Keywords: isotactic polypropylene, metallocene ethylene-propylene-based elastomers, blend, mechanical properties, adhesion parameters
Published in DiRROS: 13.12.2023; Views: 203; Downloads: 98
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100. Groundwater Characterization by Means of Conservative (δ18O and δ2H) and Non-Conservative (87Sr/86Sr) Isotopic Values: The Classical Karst Region Aquifer Case (Italy–Slovenia)Chiara Calligaris, Kim Mezga, Francesca Federica Slejko, Janko Urbanc, Luca Zini, 2018, original scientific article Abstract: The study of the different hydrogeological compartments is a prerequisite for understanding and monitoring different fluxes, thereby evaluating the environmental changes in an ecosystem where anthropogenic disturbances are present in order to preserve the most vulnerable groundwaters from contamination and degradation. In many karst domains in the Mediterranean, areas groundwaters and surface waters are a single system, as a result of the features that facilitate the ingression of waters from surface to subsurface. This is also the case for the Classical Karst hydrostructure, which is a carbonate plateau that rises above the northern Adriatic Sea, shared between Italy and Slovenia. The main suppliers to the aquifer are the effective precipitations and the waters from three different rivers: Reka/Timavo, Soča/Isonzo and Vipava/Vipacco. Past and ongoing hydrogeological studies on the area have focused on the connections within the Classical Karst Region aquifer system through the analysis of water caves and springs hydrographs and chemographs. In this paper, the authors present new combined data from major ions, oxygen, hydrogen and strontium stable and radiogenic isotopes which have allowed a more complementary knowledge of the groundwater circulation, provenance and water-rock interactions. All the actions occurred in the framework of the European project HYDROKARST.
Keywords: podzemna voda, kras, geokemija, izotopi, Hydrokarst projekt
Published in DiRROS: 12.12.2023; Views: 212; Downloads: 124
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