• Energy Research
• 2021-2025close
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Synopsis Climate change can directly and indirectly affect species distribution. Warming may allow for invasive species, such as apple snails, to migrate to higher latitudes where temperatures are more conducive to their survival and invasion success. Higher temperatures and lower pH ranges have been previously documented to affect the form and function of calcium carbonate shells, which serve many functions, including protection from predators and thermoregulation. This study aimed to quantify differences in the morphology and mechanical properties of invasive apple snail, Pomacea maculata, shells after altering temperature and pH. We mechanically tested shells among three five-week treatments: control, higher temperature, and lower pH. Ultimate Strength increased in shells that were exposed to higher temperatures, but Young’s Modulus and Peak Load did not differ among control, temperature, and pH treatments. Apple snails in higher temperature tanks increased their shell length over the five-week trials. Although snail morphometrics did not differ between sexes, male shells exhibited a higher Peak Load, Young’s Modulus, and Ultimate Strength compared to female shells. Our findings are consistent with previous gastropod studies, in that a lower pH is associated with a decrease in shell size, and higher temperatures yield larger snail shells with a higher ultimate strength. Peak Load did not significantly differ among treatments, which suggests that the cross-sectional area is relatively important when considering this species mechanical performance today and in future climates. Due to the intense nutritional and calcium demands of egg production, female snails may be more susceptible to weakened shells due to low pH environments caused by climate change.

The paper presents a computer simulation of the operation of three independent electric drives with a periodic load, connected to a common power supply network. Two cases are considered - operation of electric drives in one phase and in different phases. An analysis of their impact on the electrical supply network is carried out, the results are compared with the permissible Russian standards. An analytical optimization method based on the analysis of power graphs of electric drives with periodic load was considered. The article contains an overview of possible methods for regulating the working phase of the mechanism.

This research investigates the flight behavior of refuse-derived fuel (RDF) in a drop shaft using Computer Vision to obtain statistical data on the aerodynamic properties of the particles. Methods to determine 3D geometry models of complex-shaped particles by photogrammetry and to obtain time resolved particle positions and velocities are described. Furthermore, an approach to obtain the frequency distribution of drag and lift coefficients from photogrammetric analysis and drop shaft experiments is presented. The image evaluation is based on algorithms of the open-source libraries OpenCV, COLMAP as well as MeshLab and Open3D. The precision of the system is validated employing model particles with known geometry. The 3D particle models overestimate the particle surface area by 4.58 %, the position detection works with a mean deviation of 2.73 %. The average sink rate is calculated with an accuracy of 4.87 % and the drag coefficient with an accuracy of 2.08 %. Finally, the frequency distribution of four RDF fractions, namely, textiles, cardboard, 3D plastic particles and 2D plastic foils are presented.

This study aims to indicate the importance of revising current health recommendations concerning the duration of exposure and individual sensitivity of the skin to solar ultraviolet (UV) radiation. For this purpose, a 16-year data series (2005-2020) of erythemal radiant exposure (Her) and UV index (UVI) for Serbia was analyzed. The UV-related risk was estimated for lighter skin (skin phototypes I-IV) under prolonged exposure on days when maximum UVI was below the recommended protection threshold (UVIlow days, for UVI < 3). Risk assessment was performed for seasonal exposure using satellite-derived data (OMUVBd product) previously validated by ground-based measurements in Novi Sad. The assessment of harmful effects included an analysis of the relation between the daily maximum UVI and the corresponding daily Her, the occurrence of UVIlow days, the exceedance of minimal erythema dose (MED), and the minimum duration of exposure to induce erythema (tMED) for all lighter skin phototypes. It was found that the share of UVIlow days in the total number of days in Serbia increases with the latitude, with the highest percentage in winter (up to 69.454%) and the lowest in summer (up to 3.468%). The results show that the daily Her frequently exceeded the harmful threshold for lighter skin phototypes I-IV (on average by 91.521, 84.923, 70.556, and 56.515%, respectively) on UVIlow days. It was found that prolonged exposure on days with a maximum of UVI = 2 poses a significant risk of erythema for all lighter skin phototypes, even for a duration of 3 h in the middle of the day, as well as medium risk for UVI = 1, and an absence of risk for UVI = 0. The results suggest that health recommendations should be revised, especially in the mid-latitudes, where the share of UVIlow days is large, and in areas where the population is predominantly lighter-skinned.

The environmental impact of Parmigiano Reggiano PDO cheese was quantified using the Product Environmental Footprint Category Rules (PEFCRs) in a Traditional System (TS) and in an Improved Management System (IMS). The TS differs from IMS with respect to slurry management (raw slurry storage vs anaerobic digestion and storage of the liquid fraction of digestate) and application of nutrients to the field (by slurry tanker with a diverter plate vs soil injection at pre-sowing and side dressing). Two additional scenarios were evaluated by considering the possible environmental enhancement achievable by reducing enteric methane production and by using soybean grain produced in Italy as the protein source for animals' diets. The environmental impact was quantified both for 1 kg of fat and protein corrected milk (FPCM) and for the production of 10 g dry matter equivalent of cheese as single score. For the first assessment, the environmental impact results were 124 and 112 μPt kg FPCM-1 for TS and IMS, respectively. In the second case, it was 10.8 μPt and 9.9 μPt 10 g dry matter equivalent-1 of cheese, for TS and IMS, respectively. The specific cost for reducing the GHG emissions in this production chain was equal to 34 € Mg-1 milk produced. Finally, although specific studies should consider the reduction of enteric methane emissions and the use of soybean grain nationally produced as feed source, the scenarios evaluated in this study highlighted some potential for environmental improvements. Even small environmental improvements to the Parmigiano Reggiano PDO cheese supply chain can bring substantial improvements to the sustainability of the food market, because of the widespread demand on the global market of Parmigiano Reggiano and of its chance of attracting consumers who are sensitive to environmental problems.

In recent years, the problem of assessing the replaceability of various types of raw materials and products in the energy market, in the production of heat and electricity, has become increasingly relevant. Wood fuel in the form of pellets and wood chips has several substitutes with uncertain consumption prospects. This paper presents different approaches to assessing the efficiency of using wood materials as fuels due to high expectations from the development of a "green economy", designed to replace the use of non-renewable natural resources in energy production. © Proceedings of Scientific Papers - Current Trends and Challenges for Forest-Based Sector: Carbon Neutrality and Bioeconomy, WoodEMA 2023.

Pyrolysis of plastic waste is a key technology for closing the anthropogenic carbon cycle. The energy demand (ED) of this endothermic process is a crucial factor to evaluate its benefits compared to established recycling pathways. The pyrolysis ED can be determined experimentally. However, this is elaborate and limited in transferability. Existing models cover virgin plastics or hydrocarbon thermoplastic mixtures on a laboratory scale. Here, a model for calculating the ED of thermoplastic mixtures based on the superposition of virgin polymer data is developed. The material data, such as heat capacity, phase transition enthalpy, and reaction enthalpy, are determined using differential scanning calorimetry. Pilot-scale experiments are performed in a 1 kg/h screw reactor. These experimental data are compared to model calculations. The feedstock-specific ED for pyrolysis is plastic-type independent. It amounts to approximately 4−6% of the feedstocks’ net calorific value. The validation shows excellent accordance for virgin plastics and hydrocarbon plastics mixtures. The modeled ED of mixtures including heteroatoms is systematically underestimated, which indicates changes in the degradation mechanism. The model allows for resolving several phenomena contributing to the pyrolysis ED. The simple calculation of the ED with in-depth information on occurring phenomena enables more reliable process design, optimization, and evaluation.

Abstract: This paper considers the use of lignin during the preparation of phenol-formaldehyde resins. The effect of lignin on the properties of phenol-formaldehyde resins and materials based on them is studied. The obtained resins are characterized by differential scanning calorimetry (DSC). The results show that, in the case of increasing the concentration of lignin, the time of the polycondensation reaction, the energy of activation, and the curing time of lignin-containing resins increase. The main parameters of the lignin-containing resins correspond to GOST (State Standard) 20907–2016 except for the concentration of free formaldehyde. The obtained resins are used to obtain a foam composite material—phenolic foam. It is noted that phenolic foams based on resins containing 5–10% lignin in the composition have a higher compression strength in comparison with other samples. At a concentration of lignin in the resin of 20%, the compression strength of the ready-to-use thermal-insulation materials decreases relative to other samples, while it turns out to be impossible to obtain a foam material in the case of using a resin with 30% lignin. The results of the study make it possible to recommend the use of a small amount of lignin (5–10%) in the production of phenol-formaldehyde resins and further production of a thermal-insulation material with an increased compression strength. © 2023, Pleiades Publishing, Ltd.