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Superbases as Organocatalysts in Low Temperature Glycolytic Depolymerization of Polyethylene Terephthalate (PET)
No full textChemical recycling offers a prospective solution for valorizing the vast amount of diverse polyethylene terephthalate (PET) waste generated from various streams. Rigid and flexible packaging such as bottles, and films, or textiles, optionally containing also comonomers like polypropylene terephthalate (PPT) and polybutylene terephthalate (PBT), are essential materials to be considered. In this study, low temperature depolymerization of PET was investigated by implementing glycolysis as the chemical recycling method. In glycolysis of PET, the polymer is depolymerized in excess ethylene glycol and presence of catalyst into bis(2-hydroxyethyl) terephthalate (BHET) monomer. The monomer can be re-utilized as feedstock for the manufacturing of recycled virgin-like PET. Herein we report utilization of novel mTBN guanidine superbase (mixture of two isomers, 7-methyl-1,5,7-triazabicyclo-[4.3.0]non-5-ene & 5-methyl-1,5,7-triazabicyclo-[4.3.0]non-6-ene) as efficient organocatalyst for glycolysis of virgin and post-consumer PET materials. Three guanidine compounds were screened as catalyst under various conditions and their efficiency was compared to zinc acetate, which is a conventionally applied transesterification catalyst. All superbases achieved high PET conversions of over 90 % at low reaction temperature of 140 °C within 2 h, while Zn(OAc) 2 showed only 18 % conversion. Moreover, mTBN superbase was the most efficient by depolymerizing PET powder in just 20 min. Industrially viable conversions of over 90 % resulted in BHET monomer recovery of over 40 % determined by mass. Size-exclusion chromatography (SEC) results indicate that reaction temperature has significant influence on the depolymerization reaction depth. Furthermore, experiments with different PET feedstocks demonstrate the significance of materials’ surface area towards depolymerization efficiency.</p
Towards Real-Time Design Collaboration:LiveCol Final Report
Get PDFLiveCol set out to develop and validate methods and tools that enable realtime,data-driven collaboration in construction design. The project aimedto move from differentiated, semi-coordinated workflows toward parallel,open, and up-to-date information management supported by 3D tools andintegrated communication services
Mono- and bimetallic platinum-based catalysts in dehydrogenation of perhydro dibenzyltoluene
Get PDFLiquid organic hydrogen carriers (LOHCs) are emerging as solutions for storing renewable hydrogen. A particularly promising LOHC candidate system is dibenzyltoluene (DBT) and its fully hydrogenated form, perhydro dibenzyltoluene (H18-DBT). The dehydrogenation reaction of H18-DBT is critical for the feasibility of the LOHC system, requiring catalysts that are active, resistant towards deactivation, and do not promote the decomposition of the LOHC compound. This study examined the dehydrogenation of H18-DBT using both monometallic Pt-catalysts and bimetallic catalysts composed of Ptsingle bondPd, Ptsingle bondRu and Ptsingle bondRe supported on alumina and titania. The extent of dehydrogenation ranged from 32% to 69% over 45 min in a batch reactor, with a molar ratio of H18-DBT to Pt of 400:1. In the series of Pt-catalysts, the highest quantity of weak acid sites and a moderate amount of medium acid sites exhibited the highest dehydrogenation activity. The bimetallic Ptsingle bondRe catalyst on alumina demonstrated improved efficiency in H18-DBT dehydrogenation, though it did not outperform the most active catalyst, monometallic Pt supported on titania. Notably, the decomposition products of H18-DBT in the hydrogen gas reached concentration of 0.03 wt% within 45 min reaction time
Investigation of the reaction kinetics of 3-chloro-2-hydroxypropyl-N,N,N-trimethylammonium chloride (CHPTAC) with cellulose fibres
No full textIn the reaction system consisting of 3-chloro-2-hydroxypropyl- N , N , N -trimethylammonium chloride (CHPTAC), sodium hydroxide, cellulose and H2O, it is widely accepted that the low reaction yield is the result of fast alkaline hydrolysis of CHPTAC. Some inconsistencies remain unexplained by rapid hydrolysis alone, indicating the need to understand the role of the cellulose-NaOH interaction to advance beyond the current state of the art. This raises two key questions: is NaOH uptake on cellulose decisive for cationisation yield, and is all epoxide consumed by end of the cationisation? Investigations into the reactions rates were conducted in the absence and the presence of cellulose fibres by applying a novel ion-exchange high-performance liquid chromatography method and nitrogen analysis to quantify both reactant in solution and product formation. It was found that hydrolysis rates are slower in the presence of the fibre, which was attributed to sorption of reactants, particularly sodium hydroxide, onto the fibre. The bonding of CHPTAC to cellulose shows initially high reaction rates but approaches a plateau, even though 40% of the cationisation agent is still available in solution. This phenomenon is attributed to the consumption of “active” (deprotonated) cellulose sites, highlighting the need for improved understanding of the cellulose-NaOH interaction, and its influence on derivatisation reactions.</p
Combustion of cables used in nuclear power plants
No full textThe combustion and subsequent reactions of cables found in nuclear power plants are investigated, including chlorosulfonated cables (CSPE cables) and a Low-smoke zero-halogen cables (LSZH cables). In some cases, the cables are irradiated with 1MGy of gamma radiation before combustion. Iodine is added to the gas phase to investigate the potential formation of organic iodides. The combustion process can be followed online with the help of FTIR. The combustion of the CSPE cable mainly releases HCl, SO2 and CS2 and aliphatic hydrocarbons. If the cables are pre-irradiated, the species released are largely the same, but the releases are lower. The LSZH cable required higher temperatures to pyrolyze and gave significant releases of acetaldehyde. This cable was not irradiated. The addition of iodine results in the formation of methyl iodide (CH3I) for the LSZH cable at 450°C. CH3I also reacts with other organics released in the combustion, forming isopropanol. The same happens for the unirradiated CSPE cable, but to a much lower degree.</p
AI-Powered Orchestration-as-a-Service for 6G Networks:The 6G-CLOUD View
No full textAs 6G networks grow more complex, managing resources and orchestrating services across diverse, dynamic, and energy-efficient environments becomes challenging. This paper presents a programmable Orchestration-as-a-Service (OaaS) Framework from the 6G-Cloud project that enables dynamic, scalable, and intelligent orchestration. The framework separates service orchestration from resource orchestration, supports network service–agnostic management, and integrates AI-driven optimization, digital twins (DT), and Cloud Continuum technologies. Finally, we demostrate the functionality and feasibility of the proposed architecture through an early-stage implementation, where an AI-powered use case for dynamic resource orchestration is validated, showing significant improvements in power efficiency and proactive resource scaling compared to baseline methods.</p
Integrated transcriptome and data-independent acquisition proteome analysis of the biosynthesis of Monascus azaphilone pigments and citrinin
No full textMonascus azaphilone pigments (MPs) are widely used functional food additives. However, Monascus may simultaneously produce the mycotoxin citrinin (CIT), compromising MPs safety. Here, we used comparative genome, transcriptome, and quantitative data-independent acquisition mass spectrometry (DIA-MS) proteome analyses to compare three representative Monascus purpureus strains: M3 with high MPs and high CIT titers, M34 with high MPs and low CIT titers, and M69 with low titers of both products. Comparative genomic analysis confirmed high similarity among these strains. Differentially expressed genes (DEGs) and differentially abundant proteins (DAPs) were identified by pairwise comparisons among the strains during peak metabolite production, and selected DEGs and DAPs were verified by reverse transcription quantitative polymerase chain reaction and parallel reaction monitoring. An integrated analysis revealed DEG/DAPs correlating with altered MPs and CIT production, providing insights for strain breeding to engineer safer and more efficient MPs production processes in the food, cosmetics and pharmaceutical industries.</p
AI-Powered Orchestration-as-a-Service for 6G Networks:The 6G-CLOUD View
No full textAs 6G networks grow more complex, managing resources and orchestrating services across diverse, dynamic, and energy-efficient environments becomes challenging. This paper presents a programmable Orchestration-as-a-Service (OaaS) Framework from the 6G-Cloud project that enables dynamic, scalable, and intelligent orchestration. The framework separates service orchestration from resource orchestration, supports network service–agnostic management, and integrates AI-driven optimization, digital twins (DT), and Cloud Continuum technologies. Finally, we demostrate the functionality and feasibility of the proposed architecture through an early-stage implementation, where an AI-powered use case for dynamic resource orchestration is validated, showing significant improvements in power efficiency and proactive resource scaling compared to baseline methods.</p
Future energy scenarios with renewables and flexibilities in distribution grids – National case study in France
No full textMedium and low voltage distribution grids are at the core of the energy transition as they are expected to host a large share of renewables and flexible resources. Their modeling within decarbonization pathways is then of great importance in providing realistic future energy scenarios. This paper investigates different scenarios at the French national scale up to 2050 while varying the electricity demand, renewables installed in both transmission and distribution grids, and the considered flexibility technologies. The methodology relies on coupling a long-term energy model (POLES) and an open-source short-term optimization framework (Backbone). POLES produces long-term decarbonization scenarios, while Backbone enables the optimization of the power system. Technical and financial impacts are studied through ten scenarios regarding produced energy, installed capacities, and investment costs. The results highlight the importance of the load demand modeling assumptions, even raising the question of the feasibility of high-demand scenarios. Also, results show that demand-side flexibility can significantly reduce the requirements in conventional storage technologies (up to 98 %). Distributed flexibilities, such as electric vehicle smart charging, are especially effective. Considering multiple types of distribution grids allows, in the end, to show that installing renewable generation at the transmission or distribution level only moderately influences global costs, with a minor advantage for centralization to limit reverse flows on transformers. The paper concludes with a comparison with other scenarios (drawn from up-to-date literature) and a discussion of the environmental footprint of these scenarios, both in terms of mineral resource consumption (raw materials) and land footprint.</p
Liquid–Liquid Extraction of Acetic Acid with 2-Methyltetrahydrofuran:Experiments, Process Modeling, and Economics
No full textAcetic acid production from renewable processes such as biomass hydrolysis and electrochemical reduction of CO2 exhibits low concentrations, which make downstream separation challenging. We measured the vapor–liquid equilibria of the binary systems acetic acid + 2-methyltetrahydrofuran (2-MTHF), methyl-t-butyl ether (MTBE) + acetic acid, and the ternary liquid–liquid equilibria of the system 2-MTHF + AA + water, fitted the data to the UNIQUAC-HOC and NRTL models, designed a hybrid extraction-distillation process for acetic acid separation with 2-MTHF, and evaluated its economics and compared with that of three other commonly used solvents (i.e., ethyl acetate, MTBE, and methyl propyl ketone). The lowest and highest costs of separation were observed for MTBE and MPK, while 2-MTHF and EA showed similar performance. The cost of separation increased exponentially as the feed concentration decreased, and renewable processes should aim for at least 5 wt % acetic acid in the feed to allow economically feasible separation.</p