Browsing by Subject "Engineering"

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A comparative life cycle assessment of a new cellulose-based composite and glass fibre reinforced composites
(2023) Liu, Yuanxi; Lask, Jan; Kupfer, Robert; Gude, Maik; Feldner, Alexander
The use of renewable lightweight materials and the adoption of cleaner production are two effective approaches to reduce resource consumption, which contributes to meeting the industry’s environmental impact targets. In a previous study we found, that a miscanthus fibre reinforced cellulose acetate (CA-Miscanthus, 25 wt.%) can be a bio-based alternative to glass fibre reinforced polypropylene (PP-GF, 20 wt.%), as both materials exhibit similar mechanical properties. However, only limited information on the environmental benefits of using bio-based composites instead of their petroleum-based counterparts are available. In this study, we compare the environmental impact of ready to use compound of both materials in the cradle to gate system boundaries, including fibre cultivation, fractionation and refining, fibre pretreatment, and compounding. The functional unit is chosen based on the equivalent function of both materials. The environmental impact is determined using the Product Environmental Footprint (PEF) methodology. The results reveal that the CA-Mis composite has a higher environmental impact than the PP-GF composite in all categories observed, despite its biomass origin. As the primary reason for the high impact, the acetic anhydride use during CA production is identified. The study indicates that, though the bio-composite CA-Mis has mechanical properties comparable to PP-GF composites, it is not as eco-friendly as we initially assumed it to be.
Tackling foam-based process disruptions in spirit distillation by thermal energy input adaptations
(2022) Heller, Daniel; Roj, Simon; Switulla, Julia; Kölling, Ralf; Einfalt, Daniel
Process impairing foam formation occurs regularly in batch distillation devices of the spirit industry. It negatively influences process and product quality. Up to now, such foam-related problems have not been in the focus of scientific investigations. This study aimed at preventing impairing foam formations by adapting the thermal energy input in fruit and grain mash distillations in larger scale batch distillations. The results showed that a reduction of the thermal energy input to 43 ± 1 W·L −1 during the initial heating of the mash leads to less flooding of the distillation apparatus and to a higher concentration of lower boiling compounds like methanol, acetaldehyde, and ethyl acetate as well as ethanol in the first fractions of the distillates. A standard process time and less energy consumption could be achieved by increasing the energy input again after prior reduction. However, this led to a reduction of the ethanol concentration in the distillate fractions of up to 4.3%vol, also most severe in the first fractions. A significant influence on analyzed volatile compounds in the distillate besides ethanol could not be detected. This is the first study that uses defined thermal energy input adaptations for foam management in larger scale distillation devices. The results lead the way to a more efficient distillation process with less foam formation.
The value of remotely sensed vs. field-surveyed habitat structure for predicting bird abundance: a case study in traditional orchards
(2022) Chaparro, Laura; Schmieder, Klaus; Schurr, Frank M.
Understanding environmental effects on the distribution and abundance of species is central to ecology, biogeography and evolutionary biology. This led to the development of species distribution models (SDMs) that relate spatial variation in occurrence and abundance to environmental variables. So far, SDMs rarely considered habitat structure, as a major determinant of bird distributions. While remote sensing increasingly provides high-resolution measures of habitat structure, certain structural variables affecting bird abundance still need to be measured with field surveys. In this study, we compare the value of remotely sensed vs. field-surveyed habitat structure for predicting bird abundance. Specifically, we analysed abundance data for nine bird species of traditional orchards in South-Western Germany. ‘Remote sensing SDMs’ related abundance to structural variables obtained by aerial photogrammetry of individual orchard trees. Alternative ‘field survey SDMs’ related bird abundance to detailed field surveys of the species composition and pruning state of orchard trees. Additionally, both remote sensing and field survey SDMs included climate and land use variables. Accounting for detailed habitat structure improved abundance predictions for seven of nine study species compared to models only incorporating climate and land use. The impact on model performance differed between remotely sensed and field-surveyed variables: the former improved abundance models for most ( n = 7) bird species, whereas the latter had more variable impact, decreasing model performance for five species. The remotely sensed variable with strongest effects was overall tree density, which positively affected abundance of seven species. In contrast, multiple field-surveyed variables had similar effect strength, with the overall strongest effect found for pear tree density, to which seven bird species showed a unimodal response. These analyses have conservation implications since they predict expected responses of bird species to ongoing changes in orchard structure. Moreover, they identify structural variables that will be most promising to measure via remote sensing data in the future.