31. Effects of specific parameters on simulations of energy use and air temperatures in offices equipped with radiant heating/cooling panelsSabina Jordan, Jože Hafner, Martina Zbašnik-Senegačnik, Andraž Legat, 2019, original scientific article Abstract: When creating a simulation model to assess the performance of buildings, there is usually a lack of feedback information. Only in the case of measurements of a real building is a direct comparison of the measured values and simulated results possible. Parameter data related to users’ behavior or other events can also be obtained. Their evaluated frequency, magnitude and duration, along with boundary conditions, are crucial for the results. It is clear that none of them can be predicted very accurately. Most of them, however, are needed for computer modeling. In this paper we analyzed the well-defined TRNSYS simulation model of offices equipped with radiant ceiling panels for heating and cooling. The model was based on real case offices and was validated based on measurements for 1 year. The analysis included simulations in order to define what effect the parameters related mainly to users have on the energy use and the indoor air temperatures. The study confirmed that specific human activities influence the annual energy use to a relatively small degree and that their effects often counteract. It also confirmed the even more important fact that although small, these activities can influence the thermal comfort of users. It is believed that despite the fact that this research was based on an analysis of offices equipped with radiant ceiling panels, most of the results could be applied generally.
Keywords: measurements, modeling, simulation, validation, analysis, energy use, temperature
Published in DiRROS: 15.09.2023; Views: 319; Downloads: 151
 Full text (1,83 MB)
This document has many files! More... |
32. Methodology for evaluating the CO2 sequestration capacity of waste ashesSara Tominc, Vilma Ducman, 2023, original scientific article Abstract: The concentration of CO2 in the atmosphere is constantly increasing, leading to an increase in the average global temperature and, thus, affecting climate change. Hence, various initiatives have been proposed to mitigate this process, among which CO2 sequestration is a technically simple and efficient approach. The spontaneous carbonation of ashes with atmospheric CO2 is very slow, and this is why accelerated carbonation is encouraged. However, not all ashes are equally suitable for this process, so a methodology to evaluate their potential should be developed. Such a methodology involves a combination of techniques, from theoretical calculations to XRF, XRD, DTA-TG, and the calcimetric determination of the CaCO3 content. The present study followed the approach of exposing ashes to accelerated carbonation conditions (4% v/v CO2, 50–55% and 80–85% RH, 20 ◦C) in a closed carbonation chamber for different periods of time until the maximum CO2 uptake is reached. The amount of sequestered CO2 was quantified by thermogravimetry. The results show that the highest CO2 sequestration capacity (33.8%) and carbonation efficiency (67.9%) were obtained for wood biomass bottom ash. This method was applied to eight combustion ashes and could serve to evaluate other ashes or comparable carbon storage materials.
Keywords: CO2 sequestration, carbonation efficiency, coal ash, wood biomass ash, co-combustion ash, DTA-TG analysis
Published in DiRROS: 08.08.2023; Views: 389; Downloads: 164
Full text (3,73 MB)
This document has many files! More...
This document is also a collection of 1 document! |
33. Makroekonomski učinki proizvodnje in predelave lesa listavcevDomen Arnič, Peter Prislan, Luka Juvančič, 2023, original scientific article Abstract: As far as the utilization of the value-added potential of hardwood assortments is concerned, we have considerable reserves in Slovenia. These could be exploited mainly by increasing the economic use of roundwood in Slovenia and by developing more technologically advanced processing methods for roundwood. The aim of this paper is to assess the untapped potential of the forest-wood chain in Slovenia using input-output models, focusing on the use of hardwood. For the whole forest-wood chain, we assessed the existing situation and tested five scenarios for the improvement of the forest-wood chain in Slovenia. We developed a national input-output model to evaluate possible scenarios for the future development of the wood-based bioeconomy. The results of scenario analysis of the input-output model show that the Slovenian wood-based bioeconomy can achieve up to 20% higher production value, a 24% increase in employment and 19% increase in household income in the future through restructuring of economic activities. In the paper, we discuss how upgrading the forestry and wood-processing industry (according to the defined scenarios) could be achieved by increasing the processing capacity of hardwoods and provide recommendations for decision makers.
Keywords: forest- and wood-based bioeconomy, hardwoods utilization, input-output models, wood processing industry, scenario analysis, mobilization of hardwoods
Published in DiRROS: 03.08.2023; Views: 338; Downloads: 180
Full text (1,21 MB)
This document has many files! More... |
34. Dataset for the article Methodology for evaluating the CO2 sequestration capacity of waste ashesVilma Ducman, Sara Tominc, 2023, complete scientific database of research data Abstract: The dataset supports the data in the tables and figures in the article Methodology for evaluating the CO2 sequestration capacity of waste ashes (doi: 10.3390/ma16155284). It contains the original masses of waste ash before and during carbonation treatment, the sequestered CO2 masses after carbonation treatment, mass uptake calculations, calcimetric measurements, calculations of theoretical maximum sequestered CO2 (based on XRF results) and carbonation efficiency (CE), original results of DTA/TG analysis of individual ashes, original results of XRF measurement and data from XRD analyses supported by X-ray diffractograms not published in the article.
Keywords: CO2 sequestration, carbonation efficiency, coal ash, wood biomass ash, co-combustion ash, DTA-TG analysis
Published in DiRROS: 14.07.2023; Views: 581; Downloads: 261
 Research data (245,99 KB)
This document has many files! More... |
35. Measurements of bridge dynamic amplification factor using bridge weigh-in-motion dataJan Kalin, Aleš Žnidarič, Andrej Anžlin, Maja Kreslin, 2022, original scientific article Abstract: The dynamic component of bridge traffic loading is commonly taken into account with a Dynamic Amplification Factor (DAF)—the ratio between the dynamic and static load effects on a bridge. In the design codes, this factor is generally more conservative than in reality. Recently a new method of cal- culation of this factor had been developed. Data from 15 different bridges have been analysed since then and this paper presents the results of the analyses. The background for Bridge Weigh-in-Motion is given, and the most recent method for DAF calculation is described. The sites from which the data originated are presented, and the selection of data discussed. The results of the analyses are presented and discussed and some examples of DAF calculations are shown. Data from the considered sites have invariably demonstrated a DAF decrease with increasing axle load. This is a significant result, especially for assessment of existing structures, since it is beneficial to use measured structural param- eters to optimise structural analysis.
Keywords: bridge loads, bridge weigh-in-motion, dynamic amplication factor, dynamic analysis, measurement, traffic loading
Published in DiRROS: 14.07.2023; Views: 315; Downloads: 167
Full text (2,61 MB)
This document has many files! More... |
36. Characterizing steel corrosion in different alkali-activated mortarsNina Gartner, Miha Hren, Tadeja Kosec, Andraž Legat, 2021, original scientific article Abstract: Alkali-activated materials (AAMs) present a promising potential alternative to ordinary Portland cement (OPC). The service life of reinforced concrete structures depends greatly on the corrosion resistance of the steel used for reinforcement. Due to the wide range and diverse properties of AAMs, the corrosion processes of steel in these materials is still relatively unknown. Three different alkali-activated mortar mixes, based on fly ash, slag, or metakaolin, were prepared for this research. An ordinary carbon-steel reinforcing bar was installed in each of the mortar mixes. In order to study the corrosion properties of steel in the selected mortars, the specimens were exposed to a saline solution in wet/dry cycles for 17 weeks, and periodic electrochemical impedance spectroscopy (EIS) measurements were performed. The propagation of corrosion damage on the embedded steel bars was followed using X-ray computed microtomography (XCT). Periodic EIS measurements of the AAMs showed different impedance response in individual AAMs. Moreover, these impedance responses also changed over the time of exposure. Interpretation of the results was based on visual and numerical analysis of the corrosion damages obtained by XCT, which confirmed corrosion damage of varying type and extent on steel bars embedded in the tested AAMs.
Keywords: corrosion, alkali-activated mortars, steel reinforcement, electrochemical impedance spectroscopy, X-ray computed microtomography, visual analysis
Published in DiRROS: 05.07.2023; Views: 385; Downloads: 180
Full text (7,00 MB)
This document has many files! More... |
37. The effect of crystalline waterproofing a dmixtures on the self-healing and permeability of concreteAnita Gojević, Vilma Ducman, Ivanka Netinger Grubeša, Ana Baričević, Ivana Banjad Pečur, 2021, original scientific article Abstract: This paper investigates the effectiveness of a specific crystalline waterproofing admixture (CWA) in concrete as a function of a water–binder ratio. Four concrete mixes with and without CWA were prepared; two of them with a water–binder ratio of 0.45 and two of them with a water– binder ratio of 0.55. Water permeability and compressive strength were tested on hardened concrete specimens and self-healing of cracks over time was observed. Cement paste and CWA paste were prepared to clarify the results obtained on the concrete specimens. SEM and EDS and XRD and FTIR were performed on the hardened pastes to explain the mechanism of CWA working. The results show that the addition of CWA had no significant effect on the compressive strength of the concrete, but reduced the water penetration depth in the concrete, and the reduction was more effective for mixes with lower water–binder ratio. Regarding the self-healing effect, it can be concluded that the addition of CWA improves the crack healing in concrete, but the efficiency of self-healing is highly dependent on the initial crack width. The mechanisms involved in the reduction of water penetration depth and crack healing in concrete can be explained by different mechanisms; one is creation of the CSH gel from unreacted clinker grains, then formation carbonate, and additional mechanism is gel formation (highly expansive Mg-rich hydro-carbonate) from magnesium based additives. The presence of sodium silicate, which would transform into carbonate/bicarbonate, also cannot be excluded.
Keywords: slag, self healing concrete, crystal admixture, microstructural analysis
Published in DiRROS: 03.07.2023; Views: 284; Downloads: 202
Full text (4,84 MB)
This document has many files! More... |
38. Quantitative in situ X-ray diffraction analysis of early hydration of belite-calcium sulfoaluminate cement at various defined temperaturesMaruša Mrak, Christian L. Lengauer, Sabina Dolenec, 2021, original scientific article Abstract: The influence of temperature on the early hydration of belite-calcium sulfoaluminate cements with two different calcium sulfate to calcium sulfoaluminate molar ratios was investigated. The phase composition and phase assemblage development of cements prepared using molar ratios of 1 and 2.5 were studied at 25, 40 and 60 ◦C by in situ X-ray powder diffraction. The Rietveld refinement method was used for quantification. The degree of hydration after 24 h was highest at ambient temperatures, but early hydration was significantly accelerated at elevated temperatures. These differences were more noticeable when we increased the temperature from 25 ◦C to 40 ◦C, than it was increased from 40 ◦C to 60 ◦C. The amount of calcium sulfate added controls the amount of the precipitated ettringite, namely, the amount of ettringite increased in the cement with a higher molar ratio. The results showed that temperature also affects full width at half maximum of ettringite peaks, which indicates a decrease in crystallite size of ettringite at elevated temperatures due to faster precipitation of ettringite. When using a calcium sulfate to calcium sulfoaluminate molar ratio of 1, higher d-values of ettringite peaks were observed at elevated temperatures, suggesting that more ions were released from the cement clinker at elevated temperatures, allowing a higher ion uptake in the ettringite structure. At a molar ratio of 2.5, less clinker is available in the cement, therefore these differences were not observed.
Keywords: in situ X-ray diffraction, hydration, temperature, cement, rietveld analysis
Published in DiRROS: 26.06.2023; Views: 337; Downloads: 197
Full text (4,59 MB)
This document has many files! More... |
39. 3D finite element analysis of a concrete dam behavior under changing hydrostatic load : a case studyPavel Žvanut, 2022, original scientific article Abstract: In this study, a large arch-gravity Moste Dam was analyzed, where an automated system for the measurements of horizontal displacements of the upper part of the dam was established. Two-dimensional (2D) and three-dimensional (3D) analyses of dam behavior, taking into account the earth pressures and the hydrostatic load, using the finite element method (FEM)-based computer program DIANA, were performed. The influence of lowering the water level of the reservoir by 6.2 m, on the horizontal displacements of the upper part of the dam, at stationary temperature conditions, was investigated. It was found that the results of the performed 2D and 3D FEM analyses fitted in very well with the result of experimentally determined measurement of horizontal displacements (which was 0.48 mm in the upstream direction) that was obtained using a hanging pendulum. An additional comparison of the results of 3D calculations showed that the finite element mesh density had a small effect on the calculated horizontal displacements.
Keywords: concrete dam, finite element method, material properties, structure behavior, measuring instruments, monitoring, ime series analysis, horizontal displacements, hydrostatic pressure
Published in DiRROS: 21.06.2023; Views: 360; Downloads: 204
Full text (5,35 MB)
This document has many files! More... |
40. PyPore3D : an open source software tool for imaging data processing and analysis of porous and multiphase mediaAmal Aboulhassan, Francesco Brun, George Kourousias, Gabriele Lanzafame, Marco Voltolini, Adriano Contillo, Lucia Mancini, 2022, original scientific article Abstract: In this work, we propose the software library PyPore3D, an open source solution for data processing of large 3D/4D tomographic data sets. PyPore3D is based on the Pore3D core library, developed thanks to the collaboration between Elettra Sincrotrone (Trieste) and the University of Trieste (Italy). The Pore3D core library is built with a distinction between the User Interface and the backend filtering, segmentation, morphological processing, skeletonisation and analysis functions. The current Pore3D version relies on the closed source IDL framework to call the backend functions and enables simple scripting procedures for streamlined data processing. PyPore3D addresses this limitation by proposing a full open source solution which provides Python wrappers to the the Pore3D C library functions. The PyPore3D library allows the users to fully use the Pore3D Core Library as an open source solution under Python and Jupyter Notebooks PyPore3D is both getting rid of all the intrinsic limitations of licensed platforms (e.g., closed source and export restrictions) and adding, when needed, the flexibility of being able to integrate scientific libraries available for Python (SciPy, TensorFlow, etc.).
Keywords: tomographic 3D/4D imaging data, image processing and analysis, open source software, Python
Published in DiRROS: 28.04.2023; Views: 491; Downloads: 160
Full text (13,72 MB)
This document has many files! More... |
