6,225 research outputs found

    KYT2022 Finnish Research Programme on Nuclear Waste Management 2019–2022 : Final Report

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    KYT2022 (Finnish Research Programme on Nuclear Waste Management 2019–2022), organised by the Ministry of Economic Affairs and Employment, was a national research programme with the objective to ensure that the authorities have sufficient levels of nuclear expertise and preparedness that are needed for safety of nuclear waste management. The starting point for public research programs on nuclear safety is that they create the conditions for maintaining the knowledge required for the continued safe and economic use of nuclear energy, developing new know-how and participating in international collaboration. The content of the KYT2022 research programme was composed of nationally important research topics, which are the safety, feasibility and acceptability of nuclear waste management. KYT2022 research programme also functioned as a discussion and information-sharing forum for the authorities, those responsible for nuclear waste management and the research organizations, which helped to make use of the limited research resources. The programme aimed to develop national research infrastructure, ensure the continuing availability of expertise, produce high-level scientific research and increase general knowledge of nuclear waste management

    Antimicrobial Peptides Aka Host Defense Peptides – From Basic Research to Therapy

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    This Special Issue reprint will address the most current and innovative developments in the field of HDP research across a range of topics, such as structure and function analysis, modes of action, anti-microbial effects, cell and animal model systems, the discovery of novel host-defense peptides, and drug development

    Modelling, Monitoring, Control and Optimization for Complex Industrial Processes

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    This reprint includes 22 research papers and an editorial, collected from the Special Issue "Modelling, Monitoring, Control and Optimization for Complex Industrial Processes", highlighting recent research advances and emerging research directions in complex industrial processes. This reprint aims to promote the research field and benefit the readers from both academic communities and industrial sectors

    Influence of reaction conditions on hydrothermal carbonization of monosaccharides

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    The grim perspective of a near future when out-of-control global warming caused by C02 emissions will threaten to put human lives in serious danger is pushing the scientific community to seek for alternatives to fossil fuels to counteract this negative trend. At the moment, fossil fuels are the main source of energy and chemical building blocks for the synthesis of plastics. Hydrothermal carbonization is a process that aims to replace fossil fuels with renewable biomass as source of energy (biofuels) and materials (platform chemicals and hydrothermal carbon). The process of hydrothermal carbonization has been known for a little more than a century as a way to mimic the natural process of coalification of biomass. It consists in a conversion of wet biomass in water, at subcritical temperatures (180-250°C) and autogenous pressure. Biomass is made of lignin, a polymer of alkylphenol derivatives, cellulose and hemicellulose (polysaccharides). These materials, in hydrothermal conditions, undergoes a series of reaction: hydrolysis of large polymer chains, solubilisation of monomers in water, dehydration, fragmentation and ring opening reaction, oxidation and formation of organic acids and re-polymerization to amorphous carbonaceous materials. This process is extremely interesting because some of its products have been recognised as strategic for a future emancipation from fossil fuels: furan derivatives like furfural, 5-hydroxymethylfurfural and levulinic acid can be a source for the synthesis a great variety of chemicals, including biofuels. The amorphous carbonaceous materials (hydrothermal carbon) has been successfully employed as a starting material for the development of electrode in batteries, supercapacitors and fuel cells, or gas capture. However, a thorough understanding of the underlying mechanisms of hydrothermal carbonization still needs to be achieved. The aim of this research project is to evaluate the effect of the chosen parameters on the sugar conversion, the change of the product yields and the morphological and chemical properties of HT carbon; to highlight the correlation between chemicals in the liquid phase and HT carbon; to get a deeper understanding on the chemical structure of HT carbon. The attention was focused on three monosaccharides: fructose, glucose and xylose. Hydrothermal conversion of fructose was tested by varying the reaction time (2-12h), acid catalysis (H2SO4, HNO3, HCl, HBr, HI) and headspace feed gas (air, N2, CO2). The soluble and insoluble products were collected and the results discussed. Fructose proved to be a very reactive substrate for hydrothermal conversion also in plain water and absence of catalyst, leading to a maximum HMF yield of HMF of 52% after 3 h. Strong acids strongly accelerate fructose conversion to carboxylic acids but they have a less pronounced effect on HT carbon formation. A pressurized system has also a positive effect in terms of conversion. Morphological and chemical analysis of HT carbon produced showed that the alkylfuran skeleton evolves through time to a more condensed and cross-linked structure. The presence of a family of oligomers formed by units with a mass of 211 Da suggests that HT formation proceeds via progressive polymerization of a well-defined monomer. Hydrothermal conversion of glucose was performed in conditions of increasing reaction time (2-12h) and different acid catalysis (H2SO4, HNO3, HCl, HBr, HI). In this case, glucose proved to be a less sensitive substrate to dehydration than fructose. Acid catalysis greatly increase its conversion and it is possible to distinguish the different contribution of the anions in the ability to catalyse the reaction. Morphological and chemical analysis of HT carbon produced showed similar results to those obtained from fructose but also suggest that HMF concentration throughout time plays a key role in the growth rate of carbon particles. Oligomers species were also detected in this case. Finally, the effect of reaction time (2-12h) was evaluated for the hydrothermal conversion of xylose. The structural difference between xylose and the previously studied fructose and glucose has a profound impact on its reactivity in hydrothermal conditions. Although the time scale of its conversion to FF is roughly comparable to glucose conversion to HMF, FF is notably more stable than its hexose-derived furan analogous. Its relative stability depends on the fact that there is no reaction occurring on FF that is similar to the HMF ring opening. Lower HT carbon yields also suggest that carbon formation is less efficient with FF molecules. The slight difference of the FF molecule has repercussions on the structure of carbon spheres as well as their chemical structure. HT carbon particles have a reduced tendency to aggregate as reaction time proceeds. Chemical characterization showed similarities with C6 HT carbon but also a distinctive more aromatic character that once again can be ascribed once the different chemistry of FF. In this case, a few species in the mass range between 800 Da and 1500 Da were found, whose masses increase with time, with little evidence of oligomeric nature. The kinetic modelling of the data of concentration versus reaction time allowed to find the reaction rate constants associated with glucose, fructose and xylose degradation to their dehydration products (HMF and furfural respectively) as well as the constants related to levulinic acid and hydrothermal carbon formation. These constants are in good agreement with previous studies and proves that glucose dehydration is the slowest (k=1.8 ∙10-5 s-1), followed by xylose (k=3.9 ∙10-5 s-1) and fructose (k=7.6 ∙10-5 s-1)

    Hairpin windings for high reliability and high power density electrical machines

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    In the last years the increasing demand of higher torque and power densities has led to the adoption of hairpin windings (HWs) in electrical machines, mainly in those intended for automotive applications. However, this winding topology is quite sensitive to AC losses, hence one of their main challenges is represented by their reduction. This work deals with different design aspects related to the enhancements of some performance figures of rotating electrical machines for traction applications, above all power density and reliability, mainly through the adoption of HWs.In the last years the increasing demand of higher torque and power densities has led to the adoption of hairpin windings (HWs) in electrical machines, mainly in those intended for automotive applications. However, this winding topology is quite sensitive to AC losses, hence one of their main challenges is represented by their reduction. This work deals with different design aspects related to the enhancements of some performance figures of rotating electrical machines for traction applications, above all power density and reliability, mainly through the adoption of HWs

    Next-decade needs for 3-D ionosphere imaging

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    Accurately imaging the 3-D ionospheric variation and its temporal evolution has always been a challenging task for the space weather community. Recent decades have witnessed tremendous steps forward in implementing ionospheric imaging, with the rapid growth of ionospheric data availability from multiple ground-based and space-borne sources. 3-D ionospheric imaging can yield altitude-resolved electron density and total electron content (TEC) distribution in the target region. It offers an essential tool for better specification and understanding of ionospheric dynamical variations, as well as for space weather applications to support government and industry preparedness and mitigation of extreme space weather impact. To better meet the above goals within the next decade, this perspective paper recommends continuous investment across agencies and joint studies through the community, in support of advancing 3-D ionospheric imaging approach with finer resolution and precision, better error covariance specification and uncertainty quantification, improved ionospheric driver estimation, support space weather nowcast and forecast, and sustained effort to increase global data coverage

    Addressing infrastructure challenges posed by the Harwich Formation through understanding its geological origins

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    Variable deposits known to make up the sequence of the Harwich Formation in London have been the subject of ongoing uncertainty within the engineering industry. Current stratigraphical subdivisions do not account for the systematic recognition of individual members in unexposed ground where recovered material is usually disturbed - fines are flushed out during the drilling process and loose materials are often lost or mixed with the surrounding layers. Most engineering problems associated with the Harwich Formation deposits are down to their unconsolidated nature and irregular cementation within layers. The consequent engineering hazards are commonly reflected in high permeability, raised groundwater pressures, ground settlements - when found near the surface and poor stability - when exposed during excavations or tunnelling operations. This frequently leads to sudden design changes or requires contingency measures during construction. All of these can result in damaged equipment, slow progress, and unforeseen costs. This research proposes a facies-based approach where the lithological facies assigned were identified based on reinterpretation of available borehole data from various ground investigations in London, supported by visual inspection of deposits in-situ and a selection of laboratory testing including Particle Size Distribution, Optical and Scanning Electron Microscopy and X-ray Diffraction analyses. Two ground models were developed as a result: 1st a 3D geological model (MOVE model) of the stratigraphy found within the study area that explores the influence of local structural processes controlling/affecting these sediments pre-, syn- and post- deposition and 2nd a sequence stratigraphic model (Dionisos Flow model) unveiling stratal geometries of facies at various stages of accretion. The models present a series of sediment distribution maps, localised 3D views and cross-sections that aim to provide a novel approach to assist the geotechnical industry in predicting the likely distribution of the Harwich Formation deposits, decreasing the engineering risks associated with this stratum.Open Acces
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