维也纳自然资源与生命科学大学

The lyocell process, which utilizes N-methylmorpholine N-oxide monohydrate (NMMO) as a direct, non-derivatizing solvent for cellulose, currently represents the most environmentally benign technology for producing man-made cellulosic fibers. While dissolution and spinning are often perceived as physical processes, the system is, in fact, governed by a complex network of chemical side reactions. This review provides a critical examination of the “chemistry” of the lyocell process, with a focus on developments from the past two decades. The discussion encompasses the homolytic (radical) and heterolytic (ionic) degradation pathways of NMMO, which lead to solvent consumption and the formation of byproducts, such as N-methylmorpholine and morpholine. These reactions are linked to the autocatalytic degradation of NMMO and related “exothermic events”, but also to oxidative degradation of cellulose, resulting in chain scission and the generation of carbonyl functionalities. A significant consequence of these processes is the formation of chromophores, which cause discoloration of the spinning dope and the final fibers; their identification and formation mechanisms are also discussed. Given the unavoidable nature of these side reactions, a substantial part of this account is dedicated to the chemistry of the stabilizers, with propyl gallate serving as a key example, which are introduced to minimize those side reactions and their effects. The review analyzes the dual antioxidant and intermediate-scavenging roles of stabilizers, their consumption mechanisms, and their unintended involvement in chromophore generation. Finally, the influence of critical process factors, such as temperature, cellulose feedstock quality, and the impact of metal ions, is evaluated, providing a comprehensive overview of the chemical challenges and advancements in modern lyocell technology.

Aim: To quantify how interacting regional anthropogenic pressures and climate warming have driven long-term changes in wild bee community composition and diversity. Location: Eight sites within a 300 km(2) region around Linz, Upper Austria (266-616 m a.s.l.). Methods: We analysed 11,934 museum and contemporary occurrences (out of a larger dataset of 17,515 records) of 340 wild bee species collected between 1910 and 2021. Temporal presence-absence data (in six 15-year intervals) were linked to interval-averaged temperature, precipitation and human population density (proxy for anthropogenic impact) as well as sampling effort (total number of sampling events). We fitted a single binomial generalised linear mixed model (GLMM) with species and site as random effects and species category (Intermittent, Disappearing, Appearing) interacting with environmental predictors. Post hoc trend comparisons and trait-based analyses further elucidated group-specific responses. Results: Community turnover drove an similar to 18% decline in species richness over the observation period. Disappearing specialists declined under rising human impact and warming. Intermittent species were favoured by wetter and warmer intervals but negatively affected by higher human densities. Appearing generalists expanded under warming and anthropogenic pressures with no precipitation response. Omnipresent generalists remained consistently present irrespective of environmental variation, underscoring their broad tolerance but contributing to functional homogenisation. Sampling effort improved detection but did not alter these ecological patterns. Main Conclusions: Compounded anthropogenic pressures and climate warming drive specialist losses and generalist expansions, while precipitation buffers only intermittent species. Omnipresent generalists sustain baseline pollination, but community shifts toward generalists homogenise functional diversity and undermine ecosystem-level pollination resilience. Conservation must address multiple drivers-protecting specialist habitats, maintaining connectivity as well as climate- and precipitation-sensitive refugia-to preserve functional diversity and pollination services under ongoing global change.

For silver fir (Abies alba), a species expected to play an important role in climate-change adaptation of Central European forests, seed viability in Austria appears to be declining. Therefore, it is crucial to examine the constraints on seed viability and to identify ways to counteract the observed trend. In this study, we investigated factors associated with silver fir seed viability in seed stands and seed orchards in Austria. We hypothesized that seedling emergence is affected by endogenous (tree age, species abundance) and exogenous (climatic) conditions of seed stands, and that differences in emergence occur among seed production unit types, with higher success expected in seed orchards. We conducted a common garden experiment using seed lots from 63 seed stands and 6 seed orchards across Austria to investigate the likelihood of seedling emergence as a function of the proportion of silver fir-associated forest cover in seed stands, tree age, climate parameters and seed weight. Our results show a positive relationship between seedling emergence and the proportion of silver fir-associated forest cover, as well as between seedling emergence and the maximum age of the silver trees in stands. The effect of mean annual temperature on seedling emergence depended on annual precipitation levels: seeds from stands in warmer conditions had a higher probability of emergence, but only under sufficient precipitation. Synthesis and applications. As climate change, habitat loss and fragmentation intensify, seed-sourcing strategies should explicitly incorporate ecological filters when selecting stands for seed harvest to safeguard seed viability and genetic diversity for nursery production. Seed stand management should be refocused on promoting structural conditions that enhance reproductive success, while seed orchards should continue to serve as essential sources of quality and genetically diverse reproductive material.

This study introduces the integrative concept of Temporary Material Hubs (TMHs) as a newly adapted approach to enhance long-term improvement in circularity by storing prospectively valuable waste, under current conditions not feasible or possible to recover, for future recycling capabilities. TMHs aim to optimize resource recovery by prolonging the lifespan of materials in anthropogenic cycles and avoiding premature disposal. Unlike landfilling with subsequent landfill mining (disposal and later excavation), TMHs proactively store such materials in controlled "hubs" to preserve value and enable future high-quality recovery. The conceptual framework is complemented by the known final sink concept to maintain clean material cycles. Given the lack of a clear definition of recyclability, this paper further proposes recycling pillars as guiding principles in the context of TMHs: environmental and health protection, availability of adequate recycling technologies, and economic feasibility including the availability of markets. Exemplary candidate materials for TMHs currently envisage, e.g., end-of-life wind blades and incineration residues. A SWOT analysis was used to discuss the strengths of TMHs in promoting resource optimization through postponed recycling, while identifying weaknesses such as uncertain costs and current lack of accurate technical implementation concepts. Opportunities lie in supporting European circularity goals and reducing primary material extraction, whereas threats include future regulatory uncertainties and inaccurate estimations of future waste recyclability. This study prepares the ground for future research and risk-assessment on technical, economical, and societal factors necessary for implementing TMHs on an industrial scale to ensure better functioning of the circular economy and a sustainable future.

Melamine formaldehyde resin (MFR) is one of the most common thermosetting resins for coating applications. However, its further industrial application has been limited by its high hardness, brittleness, and poor impact strength. AIndustrial innovation and academic research projects have shown great attention to nanotechnology-based resin-bonded composites. Herein, for the first time, a novel MFRcoated paper laminate composite was designed by dispersing cerium oxide nanoparticles (nanoceria) in the MFR coating. In this study, nanoceria was added to MFR composites at 0.1, 0.3, 0.5, Aand 1% by weight. The impact of different concentrations of nanoceria on the physical and mechanical resistance of MFR-coated paper laminate samples were meticulously examined. Experiment results showed that increasing the amount of nanoceria particles in MFR composites leads to notable improvements in transparency, abrasion resistance, hardness, and thermal performance. Nanoceria are renowned for their antibacterial effects, which result from the conversion of Ce3+ to Ce4+. Experimental results demonstrated that nanoceria exhibits high antibacterial activity against Escherichia coli on MFR-coated paper laminate. These findings highlight the potential of nanoceria-incorporated MFR coatings as a promising solution for antibacterial and high-performance laminated paper applications in the wood and furniture industry.