1. Sulfur speciation in Li–S batteries determined by operando laboratory X-ray emission spectroscopyAva Rajh, Alen Vižintin, Joanna Hoszowska, Robert Dominko, Matjaž Kavčič, 2024, izvirni znanstveni članek Povzetek: In this work, operando sulfur X-ray emission measurementson a Li−S battery cathode were performed using a laboratory setup as analternative to more common synchrotron radiation based absorptionstudies. Photoexcitation by an X-ray tube was used. Valence-to-core Kβ X-ray emission spectra were recorded with a wavelength dispersive crystalspectrometer in von Hamos geometry, providing excellent energyresolution and good detection efficiency. The setup was used to recordex situ S Kβ emission spectra from S cathodes from the Li−S battery andalso under operando conditions. Average S oxidation state within thebattery cathode during battery cycling was determined from the shape ofthe Kβ emission spectra. A more detailed S species characterization wasperformed by fitting a linear combination of previously measuredlaboratory synthesized standards to the measured spectra. Relative amounts of different S species in the cathode were determinedduring the cycling of the Li−S battery. The main advantage of X-ray emission spectroscopy is that it can be performed onconcentrated samples with S loading comparable to a real battery. The approach shows great promise for routine laboratory analysisof electrochemical processes in Li−S batteries and other sulfur-based systems under operando conditions.
Ključne besede: X-ray emission spectroscopy, lithium−sulfur batteries, operando measurements, oxidation state, von Hamos spectrometer
Objavljeno v DiRROS: 19.12.2024; Ogledov: 84; Prenosov: 49
 Celotno besedilo (2,22 MB)
Gradivo ima več datotek! Več... |
2. CFD-based analysis of deviations between thermocouple measurements and local gas temperatures during the cooling phase of compartment firesFlorian Put, Andrea Lucherini, Ruben Van Coile, Bart Merci, 2024, izvirni znanstveni članek Povzetek: Data from thermocouple (TC) measurements play a pivotal role in fire safety science and engineering studies. It is well-known that there are deviations from the actual local gas temperature and many studies have led to the development of correction factors. The present study focuses on these deviations inside compartments through a systematic series of CFD simulations, performed with Fire Dynamics Simulator (FDS), version 6.8.0. A canonical cubic box is used as geometry. This allows for the demonstration of the impact of the presence of smoke, with variable optical thickness, on the TC data as retrieved from FDS. Significant differences are observed between TC measurements and local gas temperatures. Corrections as developed for TC measurements in open atmospheres cannot be readily applied in compartment configurations, where smoke properties change both spatially and temporally.
Ključne besede: thermocouple measurements, CFD simulations, heat transfer, compartment fires, cooling, fire dynamics, FDS
Objavljeno v DiRROS: 28.10.2024; Ogledov: 220; Prenosov: 68
 Povezava na datoteko |
3. Efficiency of FRPU strengthening of a damaged masonry infill wall under in-plane cyclic shear loading and elevated temperaturesPetra Triller, Konrad Kwiecień, Arkadiusz Kwiecień, Uroš Bohinc, BogusŁaw Zając, Marcin Tekieli, Magdalena Szumera, Theodoros Rousakis, Vachan Vanian, Ahmet Tugrul Akyildiz, Alberto Viskovic, 2024, izvirni znanstveni članek Povzetek: This paper presents results of in-plane shear tests carried out at the ZAG laboratory in Ljubljana (Slovenia) on a RC frame with masonry infill made of clay blocks (KEBE OrthoBlock). The frame was loaded with constant vertical loads at the top of the columns and then by gradually increasing horizontal cyclic loads at the top beam level. Acquired forces and measured displacements allowed capturing hysteretic behavior for determination of dissipation energy. In addition, two Digital Image Correlation (DIC) systems, Aramis and the CivEng Vision, were used to visualize the behavior of the tested specimens, with an emphasis on computing locally required information about the behavior of highly deformable interfaces. Three types of specimens were tested in-plane: the reference specimen in form of plain RC frame, the reference specimen with constructed masonry infill without any strengthening and the specimen, previously damaged and then strengthened on both sides using glass mesh bonded to the infill and the RC frame using flexible adhesive made of polyurethane matrix (Glass Fiber Reinforced PolyUrethane - GFRPU system). The strengthening process, allowed the specimen to withstand additional cyclic loads, reaching a maximum drift of 3.6 % without serious damage disqualifying the structure from further exploitation. The GFRPU strengthening system was found to be highly effective in preventing infill collapse of damaged masonry infill wall during in-plane loading. Additionally, the results of extended thermal analysis of PU are presented as polymers are, in general, a material, poorly resistant to heat. However, the analyzed PU manifested stable properties up to 200 degrees Celsius, which makes this material promising in civil engineering applications at elevated temperatures.
Ključne besede: masonry blocks, damaged infill, fiber Reinforced PolyUrethane, external composite strengthening, in-plane shear, thermal tests, DIC measurements
Objavljeno v DiRROS: 14.08.2024; Ogledov: 367; Prenosov: 239
Celotno besedilo (21,68 MB)
Gradivo ima več datotek! Več... |
4. Challenges of implementing bridge weigh-in-motion on a century-old steel-riveted railway bridgeDoron Hekič, Mirko Kosič, Jan Kalin, Aleš Žnidarič, Andrej Anžlin, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: This study explores the challenges and methodologies involved in implementing bridge weigh-in-motion (B-WIM) system on a century-old steel riveted railway bridge. A unique aspect of this study, funded by the EU H2020 Shift2Rail Joint Undertaking, was the adaptation of B-WIM systems to the specific constraints of railway bridges since, traditionally, this technology is used to collect heavy gross vehicle loading data on road bridges. The paper details the experimental setup on an old steel-riveted railway bridge, including sensor placement and calibration processes. It highlights the complexities encountered, such as differences in bridge response due to passenger and other type of trains. It introduces the system calibration strategy using known axle loads from passenger locomotives. The study provides insights into the structural response of old steel bridges under traffic loads, contributing valuable data to the field of railway bridge monitoring and maintenance.
Ključne besede: bridge, B-WIM, bridge Weigh-in-Motion system, numerical model updating, bridge response measurements, railways
Objavljeno v DiRROS: 14.08.2024; Ogledov: 374; Prenosov: 260
Celotno besedilo (20,16 MB)
Gradivo ima več datotek! Več... |
5. Load testing of the first stress ribbon bridge in SloveniaĐorđe Đukić, Doron Hekič, Mirko Kosič, Rok Vezočnik, Andrej Anžlin, Andrej Štrukelj, Marjan Pipenbaher, Tomaž Weingerl, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: Paper presents selected results of the diagnostic load testing of a newly-built footbridge in Novo Mesto, Slovenia. The bridge is significant as the first bridge in Slovenia being built with the stress ribbon technology. The diagnostic load testing took place in March 2023 and comprised of three-stage static load testing, dynamic testing with a light truck driving over artificial obstacles, and measurement of ambient vibrations. The consistency between the actual response of the bridge and the response of the finite element (FE) model, used in the design, was evaluated by comparing vertical displacements from the static load testing, natural frequencies and mode shapes. The comparison of the results indicates a satisfactory agreement between the measurements and the response of the FE model, confirming the appropriateness of the employed FE model.
Ključne besede: bridge, bridge response measurements, stress ribon, load test
Objavljeno v DiRROS: 14.08.2024; Ogledov: 329; Prenosov: 213
Celotno besedilo (16,88 MB)
Gradivo ima več datotek! Več... |
6. Evaluation of cyanobacteria biomass derived from upgrade of phycocyanin fluorescence estimationTinkara Rozina, Bojan Sedmak, Maja Zupančič Justin, Andrej Meglič, 2017, izvirni znanstveni članek Povzetek: The number of harmful cyanobacterial blooms has increased significantly at the global level in recent years. One of the characteristics of cyanobacteria that gives them advantage over other phytoplankton organisms are auxiliary photosynthetic pigments, such as phycocyanin. This fluorescent pigment emits light at a different wavelength as chlorophyll and can therefore be used for detection of cyanobacteria in situ. In this study we used submersible phycocyanin fluorescence sensors and compare their voltage output to concentration of extracted phycocyanin, cell counts and biovolume. The relation was linear in all three cases; however, the variability of regression line slopes between different cyanobacteria strains was high in the case of PC extract concentration and cell count. The highest uniformity in the linear fits was between fluorescence signal and biovolume therefore making it the best candidate for fluorescence sensor voltage output conversion. In the context of this work we also compared different methods for PC extraction. Modifying the equations by subtracting the absorption at 750 nm almost entirely reduces the false PC concentration estimation due to sample turbidity.
Ključne besede: fluorescence measurements, phycocyanin, cyanobacteria
Objavljeno v DiRROS: 01.08.2024; Ogledov: 413; Prenosov: 172
Celotno besedilo (571,80 KB)
Gradivo ima več datotek! Več... |
7. Cell size dynamics and viability of cells exposed to hypotonic treatment and electroporation for electrofusion optimizationMarko Ušaj, Katja Trontelj, Rosana Hudej, Maša Kandušer, Damijan Miklavčič, 2009, izvirni znanstveni članek Povzetek: Background. Various electrofusion parameters have to be adjusted to obtain theoptimal electrofusion efficiency. Based on published data, good electrofusion conditions can be achieved with the hypotonic treatment. However, the duration of the hypotonic treatment before electroporation and buffer hypoosmolarity have to be adjusted in order to cause cell swelling, to avoid regulatory volume decrease and to preserve cell viability. The aims of our study were to determine cell size dynamics and viability of four different cell lines in hypotonic buffer and to study the influence of the electroporation on the selected cell line in hypotonic buffer. Materials and methods. Cell size dynamics of different cell lines exposed to hypotonic buffer and electroporation were analyzed by time-resolvedcell size measurements. The viability of hypotonically treated oržand electroporated cells was determined 24 h after the experiment by a modified crystal violet (CV) viability assay. Results. In our experimental conditions the hypotonic treatment at 100 mOsm was efficient for CHO, V79 and B16-F1 cell lines. The optimal duration of the treatment was between two and five minutes. On the other hand the same hypotonic treatment did not cause cell swelling of NS1 cells. Cell swelling was also observed after electroporation of B16-F1 in isotonic buffer and it was amplified when hypotonic buffer was used. In addition, the regulatory volume decrease was successfully inhibited with electroporation. Conclusions. Cell size dynamicsin hypotonic conditions should be studied for each cell line since they differ in their sensitivity to the hypotonic treatment. The inhibition of cell regulatory volume decrease by electroporation may be beneficial in achieving higher electrofusion efficiency. (Abstract truncated at 2000 characters)
Ključne besede: hypotonic treatment, cell swelling, regulatory volume decrease, cell size measurements, viability, electrofusion, electroporation
Objavljeno v DiRROS: 08.03.2024; Ogledov: 561; Prenosov: 181
Celotno besedilo (263,01 KB) |
8. PUR in geopolymerBarbara Horvat, Nataša Knez, Uroš Hribar, Jakob Koenig, Branka Mušič, 2024, zaključena znanstvena zbirka raziskovalnih podatkov Povzetek: The dataset supports the results shown in the tables and figures in the article entitled “Thermal insulation and flammability of composite waste polyurethane foam encapsulated in geopolymer for sustainable building envelope” (doi: 10.1016/j.jclepro.2024.141387). It contains measurements of fire-behaviour characteristics, thermal conductivity, the behaviour of the material in the electromagnetic field in relation to the frequency, mechanical and structural evaluation, as well as chemical and mineralogical analysis.
Ključne besede: measurements, waste polyurethane foam, polymeric flame retardants, alkali activated material, metakaolin, microwave irradiation, thermal-fire behaviour, mechanical strength
Objavljeno v DiRROS: 20.02.2024; Ogledov: 867; Prenosov: 311
 Raziskovalni podatki (2,51 MB)
Gradivo je zbirka in zajema 1 gradivo! |
9. Predicting the quality of grain refiners from electrical resistance measurements of aluminumMaja Vončina, Irena Paulin, Jože Medved, Mitja Petrič, 2023, izvirni znanstveni članek Ključne besede: Al-Ti-B grain-refiners, quality, TiB2 particles, Al3Ti particles, electrical resistance measurements
Objavljeno v DiRROS: 01.02.2024; Ogledov: 625; Prenosov: 279
Celotno besedilo (8,93 MB)
Gradivo ima več datotek! Več... |
10. Fertilisation with potato starch wastewater effect on the growth of Scots pine (Pinus sylvestris L.) forest in PolandNella Waszak, Filipe Campelo, Iain Robertson, Radosław Puchałka, Fatima-Zahraa El Balghiti, Jožica Gričar, Ali Boularbah, M. Koprowski, 2024, izvirni znanstveni članek Povzetek: Fertilisation is often used to increase plant productivity in agriculture but has also been used in forestry. In our study, Scots pine forest growing in a nitrogen-poor environment was fertilised with NPK post-production wastewater from a potato starch factory. Our research aimed to investigate the dependence of tree growth on different NPK concentrations. Cell characteristics such as cell wall thickness (CWT), lumen diameter (LD) and tree-ring features such as ring width (RW), total number of cells in annual growth (nTotal), earlywood (EW) and latewood (LW) were investigated. Twenty-six years of regular fertilisation of the forest with different doses of wastewater rich in NPK elements have affected the anatomical structure of Scots pine trees. It is presumed that the reduction in CWT and LD on the fertilised site was due to deficiencies in plant water conductivity, which may have occurred due to physiological drought. The influence of nitrogen on unfertilised site from the wastewater area could contribute to the CWT thickening. The results confirm that the use of NPK in excessive doses is detrimental to trees' conductive system.
Ključne besede: wastewater effluents, forest fertilisation, cell measurements, tree-ring width, wood anatomy
Objavljeno v DiRROS: 03.01.2024; Ogledov: 679; Prenosov: 365
Celotno besedilo (4,94 MB)
Gradivo ima več datotek! Več... |
