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Sirvi Autor "Mencarelli, A." järgi

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  • Pisipilt
    Kirje
    Physical parameters kinetics during the drying process of quarters and halves cut tomatoes
    (Estonian University of Life Sciences, 2023) Mencarelli, A.; Marinello, F.; Marini, A.; Guerrini, L.
    Tomato drying is a time-consuming industrial process. Moreover, the prolonged use of high temperatures decreases the quality of tomatoes and increases the environmental footprint of the process. In most cases, drying is performed on halved tomatoes. Alternatively, the use of quarter tomatoes could guarantee a drying times reduction without compromising the final product quality. This work aimed at modelling changes in physical characteristics of half and quarter tomatoes. The drying tests were conducted at 50 and 60 °C. The kinetics of weight loss, colour change, and volume reduction were determined. Colour change was monitored through image analysis, while volume reduction using RGB-D reconstructions. Based on the results, an increase in the drying temperature and the use of quartered tomatoes allow a significant reduction in drying times. The loss of water kinetic allowed the determination of critical moisture. Between initial and critical moisture, loss of water occurred at constant rate (zero-order kinetic), while after that the rate decreased exponentially (first-order kinetic). The colour kinetics showed an initial constant rate followed by a linear increase for brown pixels. The variation of red pixels did not have a clear trend. Increasing the temperature there was no significant reduction in colour quality while quarter tomatoes showed a greater loss of redness than halved tomatoes. Furthermore, the temperature increase does not affect the volume reduction of the tomatoes. Increasing the temperature and the use of quartered tomatoes are simple solutions to reduce drying times. However, quartered tomatoes are less visually appreciable than halved tomatoes.
  • Pisipilt
    Kirje
    Qualitative assessment of beach wrack and the influence of pretreatment methods on fuel characterization for energy production
    (Estonian University of Life Sciences, 2025) Mencarelli, A.; Greco, R.; Grigolato, S.
    The accumulation of beach wracks poses significant challenges to coastal management, particularly in tourist areas, affecting environmental quality and aesthetics. This study explores the qualitative characteristics of beach wrack as a biofuel source for combustion appliances. Samples collected from beaches in Veneto, Italy, were analyzed according to EN ISO standards for solid biofuels. Proximate and ultimate analysis, heating value, and ash melting behaviour were determined. Raw samples (BW-R) exhibited high moisture content (77%), a substantial ash content (44%), and low heating value (10.7 MJ kg-1), making them unsuitable for direct energy applications. Pretreatments were performed to enhance the properties of the material. One portion was mechanically sieved (BW-S) to remove sand, while another was sieved and washed (BWSW) to remove the remaining salt and sand. Sieving reduced the ash content to 24% and increased the heating value to 15.3 MJ kg-1. The key improvements came from washing and sieving, which lowered ash content to 13% and increased heating value to 18.1 MJ kg-1. Washing also raised the ash deformation temperature to 1,290 °C, enhancing thermal stability. Pretreatments increased C and H content while reducing S and O, with no significant change in N. Due to high ash content, mixing with sawdust was necessary, resulting in mixtures showing better properties: 4.0% ash for Mix30 (30% beach wrack, 70% sawdust) and 6.9% for Mix50 (50% each) and increased heating values. However, challenges remain in converting beach wrack into viable fuel due to material losses during pretreatment, high costs, and environmental concerns from plastics.