1511. Tehnične smernice za ohranjanje in rabo genskih virov : maklen, trokrpi javor in tatarski javor = Acer campestre, Acer monspessulanum, Acer tataricumJože Bavcon, Gregor Božič, Lado Kutnar, Boštjan Košiček, 2011, strokovni članek Ključne besede: genski viri, drevesne vrste, tehnične smernice, javor, maklen, poljski javor, Acer campestre, trokrpi javor, Acer monspessulanum, tatarski javor, Acer tataricum, Slovenija
Objavljeno v DiRROS: 20.12.2023; Ogledov: 303; Prenosov: 76
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1514. Effect of the cooling regime on the mineralogy and reactivity of belite-sulfoaluminate clinkersSabina Dolenec, Katarina Šter, Maruša Mrak, Klara Žagar, Andrej Ipavec, Lea Žibret, 2020, izvirni znanstveni članek Povzetek: This study investigated the influence of different cooling regimes on the microstructure and consequent reactivity of belite-sulfoaluminate clinkers. The cement clinkers were synthesized by incorporating secondary raw materials, such as titanogypsum and bottom ash, to the natural raw materials. Clinker phases were determined by Rietveld quantitative phase analysis, while the distribution morphology and the incorporation of substitute ions in the phases were characterized by scanning electron microscopy using energy-dispersive X-ray spectroscopy (SEM/EDS). Clinker reactivity was studied using isothermal calorimetry and was additionally investigated through compressive strength, which was determined for the cement prepared from the synthesized clinkers. X-ray diffraction analysis showed that, as well as the three main phases (belite, calcium sulfoaluminate, and ferrite), the clinkers contained additional minor phases (mayenite, gehlenite, arkanite, periclase, and perovskite), the ratios of which varied according to the cooling regime utilized. Microscopic observations indicated that the cooling regime also influenced the crystal size and morphology of the main phases, which consequently affected clinker reactivity. Furthermore, a smaller amount of substitute elements was incorporated in the main phases when cooling was slowed. Results showed that, in comparison to clinkers cooled at slower rates, air quenched clinkers reacted faster and exhibited a higher compressive strength at 7 days.
Ključne besede: clinkers, belite, calcium sulfoaluminate, cooling, microstructure, reactivity
Objavljeno v DiRROS: 20.12.2023; Ogledov: 280; Prenosov: 117
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1515. Raman microspectroscopy of garnets from Sfibulae from the archaeological site Lajh (Slovenia)Saša Kos, Matej Dolenec, Judita Lux, Sabina Dolenec, 2020, izvirni znanstveni članek Povzetek: 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.
Ključne besede: garnets, inclusions, Sfibulae, Late Antiquity, provenance, Raman microspectroscopy, XRF spectroscopy
Objavljeno v DiRROS: 20.12.2023; Ogledov: 270; Prenosov: 194
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1516. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: bacterial adhesion, Streptococcus mutans, polymethyl methacrylate resin, TiO2, surface properties
Objavljeno v DiRROS: 20.12.2023; Ogledov: 242; Prenosov: 127
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1517. Efficiency of a corrosion inhibitor on bare, oxidized and real archeological bronze in indoor polluted atmosphere - digital image correlation approachTadeja Kosec, Polonca Ropret, 2021, izvirni znanstveni članek Povzetek: 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.
Ključne besede: bronze, inhibitor, corrosion, Raman
Objavljeno v DiRROS: 20.12.2023; Ogledov: 273; Prenosov: 148
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1518. Analysis of loading profile effect on testing machine calibration resultsMiha Hiti, 2021, izvirni znanstveni članek Povzetek: 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.
Ključne besede: force calibration, loading profile, measurement uncertainty, continuous loading
Objavljeno v DiRROS: 20.12.2023; Ogledov: 284; Prenosov: 133
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1519. Compensation of synchronization error effect in testing machine calibrationMiha Hiti, 2021, izvirni znanstveni članek Povzetek: 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.
Ključne besede: force calibration, loading profile, measurement uncertainty, continuous loading
Objavljeno v DiRROS: 20.12.2023; Ogledov: 253; Prenosov: 114
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