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Povzetek: The main objective of the present study was to increase the specific surface area (SBET) of graphitic carbon nitride (g-C3N4) prepared from dicyandiamide by effectively modifying the synthesis procedure using the Simplex optimization method. A remarkable increase in SBET was achieved in only a few steps, with the highest value of 86 m2/g. Compared to the reference material, the improved photocatalyst exhibited enhanced and unique structural, textural, optical, and electronic properties, reflected in the improved ability of the photocatalyst to degrade a variety of organic pollutants dissolved in water. By performing scavenger and spin-trapping experiments, it was confirmed that the major reactive oxygen species formed under visible-light illumination of the enhanced photocatalyst were singlet oxygen (1O2) and superoxide anion radicals (O2–•) with a purposed formation mechanism. The enhanced formation of 1O2 enabled high activity and stability of the optimized materials as well as selective response to degradation of the pharmaceutical compounds studied. By using the simple and fast Simplex optimization algorithm to determine new synthesis parameters, we obtained an improved g-C3N4 that completely degrades bisphenol A under the conditions studied.
Objavljeno v DiRROS: 08.11.2023; Ogledov: 228; Prenosov: 128
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Ključne besede: forest policy, nature protection, cross-sectoral impacts, compensation payments
Objavljeno v DiRROS: 05.10.2023; Ogledov: 387; Prenosov: 99
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Povzetek: This paper develops a novel method of bridge damage detection using statistical analysis of data from an acceleration-based bridge weigh-in-motion (BWIM) system. Bridge dynamic analysis using a vehicle-bridge interaction model is carried out to obtain bridge accelerations, and the BWIM concept is applied to infer the vehicle axle weights. A large volume of traffic data tends to remain consistent (e.g., most frequent gross vehicle weight (GVW) of 3-axle trucks); therefore, the statistical properties of inferred vehicle weights are used to develop a bridge damage detection technique. Global change of bridge stiffness due to a change in the elastic modulus of concrete is used as a proxy of bridge damage. This approach has the advantage of overcoming the variability in acceleration signals due to the wide variety of source excitations/vehicles–data from a large number of different vehicles can be easily combined in the form of inferred vehicle weight. One year of experimental data from a short-span reinforced concrete bridge in Slovenia is used to assess the effectiveness of the new approach. Although the acceleration-based BWIM system is inaccurate for finding vehicle axle-weights, it is found to be effective in detecting damage using statistical analysis. It is shown through simulation as well as by experimental analysis that a significant change in the statistical properties of the inferred BWIM data results from changes in the bridge condition.
Ključne besede: bridge health monitoring, bridge WIM, structural dynamics, damage detection, vehicle-bridge interaction
Objavljeno v DiRROS: 12.09.2023; Ogledov: 260; Prenosov: 134
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Povzetek: The soil organic carbon (SOC) was determined in soils of enclosed karst depressions (dolines) (NW Dinaric Mts.) to define their potential for organic carbon sequestration. SOC was measured in the forest, succession (scrubland), and grassland plots at the bottom of dolines at four depths (0–40 cm) and for 40 cm soil layer SOC stock was calculated. We demonstrated that the prevailing fine soil fractions, the C/N ratio and soil thickness play a positive role in the storage capacity of SOC in dolines regardless land use type. Grasslands have the lowest SOC storage capacity (106 t/ha/40 cm), while the highest SOC storage capacity is in succession plots (130 t/ha/40 cm). The last are covered by shrub communities dominated by Prunus spinosa, forming dense communities, and are typical of abandoned croplands or meadows that have been impacted by high levels of nutrients during cultivation phase. At this stage, there is no additional nutrient input in studied plots, which lowers the nutrient content and increases the C/N ratio. C/N ratio is the highest in the forest, where SOC stock capacity is 116 t/ha/40 cm. Given the trend towards the abandonment of agricultural land at Kras Plateau (SW Slovenia), we can expect more overgrowth of dolines, and thus an increase in carbon stocks and stabilization of organic carbon in forest soils. In contrary, we noticed the alarming decrease in grasslands and increase in urban land. The SOC storage in 2020 was for 12,538 t/ha/40 cm lower than in 2002. Although grasslands showed the lowest SOC storage, their contribution to total SOC storage in dolines is very important. Since there is a lack of studies on carbon stocks in doline soils, our research is of great importance and a novelty and gives an important background for further research on SOC stock in karst landscapes worldwide.
Ključne besede: organic carbon sequestration, karst, grassland, forests, scrubland, dolines
Objavljeno v DiRROS: 20.04.2023; Ogledov: 362; Prenosov: 236
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Ključne besede: biochemistry, nanoparticles, magnetic nanoparticles, proteins, biosensors
Objavljeno v DiRROS: 16.03.2023; Ogledov: 497; Prenosov: 199
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