Life cycle assessment of nanocellulose-reinforced advanced fibre composites

The research and development of nanocellulose-reinforced polymer composites have dramatically increased in the recent years due to the possibility of exploiting the high tensile stiffness and strength of nanocellulose. In the work, the environmental impacts of bacterial cellulose (BC)- and nanofibrillated cellulose (NFC)-reinforced epoxy composites were evaluated using life cycle assessment (LCA). Neat polylactide (PLA) and 30% randomly oriented glass fibre-reinforced polypropylene (GF/PP) composites were used as benchmark materials for comparison. Our cradle-to-gate LCA showed that BC- and NFC-reinforced epoxy composites have higher global warming potential (GWP) and abiotic depletion potential of fossil fuels (ADf) compared to neat PLA and GF/PP even though the specific tensile moduli of the nanocellulose-reinforced epoxy composites were higher than neat PLA and GF/PP. However, when the use phase and the end-of-life of nanocellulose-reinforced epoxy composites were considered, the “green credentials” of nanocellulose-reinforced epoxy composites were comparable to that of neat PLA and GF/PP composites. Our life cycle scenario analysis showed that the cradle-to-grave GWP and ADf of BC- and NFC-reinforced epoxy composites could be lower than neat PLA when the composites contains more than 60 vol.-% nanocellulose. Our LCA model suggests that nanocellulose-reinforced epoxy composites with high nanocellulose loading is desired to produce materials with “greener credentials” than the best performing commercially available bio-derived polymer

Full configuration interaction calculation of singlet excited states of Be3

The full configuration interaction (FCI) study of the singlets vertical spectrum of the neutral beryllium trimer has been performed using atomic natural orbitals [3s2p1d] basis set. The FCI triangular equilibrium structure of the ground state has been used to calculate the FCI vertical excitation energies up to 4.8 eV. The FCI vertical ionization potential for the same geometry and basis set amounts to 7.6292 eV. The FCI dipole and quadrupole transition moments from the ground state are reported as well. The FCI electric quadrupole moment of the X 3A1′ ground state has been also calculated with the same basis set (Θzz = −2.6461 a.u., Θxx = Θyy = −1/2Θzz). Twelve of the 19 calculated excited singlets are doubly excited states. Most of the states have large multiconfigurational character. These results provide benchmark values for electronic correlation multireference methods. (4e×6MO)CAS-SDCI values for the same energies and properties are also [email protected]

Life cycle assessment of a polymer electrolyte membrane fuel cell system for passenger vehicles

In moving towards a more sustainable society, hydrogen fueled polymer electrolyte membrane (PEM) fuel cell technology is seen as a great opportunity to reduce the environmental impact of the transport sector. However, decision makers have the challenge of understanding the real environmental consequences of producing fuel cell vehicles (FCVs) compared to alternative green cars, such as battery electric vehicles (BEVs). and more conventional internal combustion engine vehicles (ICEVs). In this work, we presented a comprehensive life cycle assessment (LCA) of a FCV focused on its manufacturing phase and compared with the production of a BEV and an ICEV. For the manufacturing phase, the FCV inventories started from the catalyst layer to the glider, including the hydrogen tank. A sensitivity analysis on some of the key components of the fuel cell stack and the FC system (such as balance-of-plant and hydrogen tank) was carried out to account for different assumptions on materials and inventory models. The production process of the fuel cell vehicle showed a higher environmental impact compared to the production of the other two vehicles power sources. This is mainly due to the hydrogen tank and the fuel cell stack. However, by combining the results of the sensitivity analysis for each component - a best-case scenario showed that there is the potential for a 25% reduction in the climate change impact category for the FCV compared to a baseline FCV scenario. Reducing the environmental impact associated with the manufacture of fuel cell vehicles represents an important challenge. The entire life cycle has also been considered and the manufacturing, use and disposal of FCV, electric vehicle and conventional diesel vehicle were compared. Overall, the ICEV showed the highest GWP and this was mainly due to the use phase and the fossil carbon emissions associated to the use of diesel

DIGITAL TECHNOLOGIES IN COMPLETE REMOVABLE DENTURE: A CASE SERIES

Aim: complete removable denture has been the last prosthetic procedure to follow the digitization because of drawbacks into the intraoral scans of edentulous arches; in addition, it is impossible to record muco-compressive impressions through IOS. So, a full digital procedure is not yet conceivable. We considered the possibility of an “hybrid” protocol thanks to a specific software. The hybrid protocol requires traditional techniques for the anatomical impression followed by laboratory scan of casts and wax. Methods: the software consists in two synergic programs: - Ruthinium Digital Preview allows to have a picture of the prosthetic project and change it previously, thanks to two calibrated photographs. - Ruthinium Denture Guide is a 3D software that helps laboratory work into denture production, particularly to a correct setting of acrylic teeth. The planned dental setting is printed in a template. Template and base plate, both 3D printed, are connected thanks to a structure that ensures the designed occlusal scheme. Results: the collected clinical cases did not allow a statistic analysis about patient and clinical satisfaction through evaluation questionnaires. Conclusion: it looks like that patients appreciate the prosthetic rehabilitation previsualization and in particular being actively involved in aesthetic choices. Clinically, it appears to be a shorter need for touch-ups at the last appointment; probably because of the 3D tooth position planning

Full-Configuration-Interaction Study of the Metal-Insulator Transition in Model Systems: Li_N Linear Chains (N=2,4,6,8)

International audienceThe precursor of the metal-insulator transition is studied at ab initio level in linear chains of equally spaced lithium atoms. In particular, full configuration interaction calculations (up to 1×109 determinants) are performed, in order to take into account the different nature of the wave function at different internuclear distances. Several indicators of the Metal-Insulator transition (minimum of the energy gap, maximum of the localization tensor or of the polarizability) are considered and discussed. It is shown that the different indicators give concordant results, showing a rapid change in the nature of the wave function at an internuclear distance of about 7bohrs

Crosstalks of GSK3 signaling with the mTOR network and effects on targeted therapy of cancer

Abstract The introduction of therapeutics targeting specific tumor-promoting oncogenic or non-oncogenic signaling pathways has revolutionized cancer treatment. Mechanistic (previously mammalian) target of rapamycin (mTOR), a highly conserved Ser/Thr kinase, is a central hub of the phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR network, one of the most frequently deregulated signaling pathways in cancer, that makes it an attractive target for therapy. Numerous mTOR inhibitors have progressed to clinical trials and two of them have been officially approved as anticancer therapeutics. However, mTOR-targeting drugs have met with a very limited success in cancer patients. Frequently, the primary impediment to a successful targeted therapy in cancer is drug-resistance, either from the very beginning of the therapy (innate resistance) or after an initial response and upon repeated drug treatment (evasive or acquired resistance). Drug-resistance leads to treatment failure and relapse/progression of the disease. Resistance to mTOR inhibitors depends, among other reasons, on activation/deactivation of several signaling pathways, included those regulated by glycogen synthase kinase-3 (GSK3), a protein that targets a vast number of substrates in its repertoire, thereby orchestrating many processes that include cell proliferation and survival, metabolism, differentiation, and stemness. A detailed knowledge of the rewiring of signaling pathways triggered by exposure to mTOR inhibitors is critical to our understanding of the consequences such perturbations cause in tumors, including the emergence of drug-resistant cells. Here, we provide the reader with an updated overview of intricate circuitries that connect mTOR and GSK3 and we relate them to the efficacy (or lack of efficacy) of mTOR inhibitors in cancer cells

The localization spread and polarizability of rings and periodic chains

The localization spread gives a criterion to decide between metallic and insulating behavior of a material. It is defined as the second moment cumulant of the many-body position operator, divided by the number of electrons. Different operators are used for systems treated with open or periodic boundary conditions. In particular, in the case of periodic systems, we use the complex position definition, which was already used in similar contexts for the treatment of both classical and quantum situations. In this study, we show that the localization spread evaluated on a finite ring system of radius R with open boundary conditions leads, in the large R limit, to the same formula derived by Resta and co-workers [C. Sgiarovello, M. Peressi, and R. Resta, Phys. Rev. B 64, 115202 (2001)] for 1D systems with periodic Born-von Kármán boundary conditions. A second formula, alternative to Resta’s, is also given based on the sum-over-state formalism, allowing for an interesting generalization to polarizability and other similar quantities

Tunable dipolar magnetism in high-spin molecular clusters

We report on the Fe17 high-spin molecular cluster and show that this system is an exemplification of nanostructured dipolar magnetism. Each Fe17 molecule, with spin S=35/2 and axial anisotropy as small as D=-0.02K, is the magnetic unit that can be chemically arranged in different packing crystals whilst preserving both spin ground-state and anisotropy. For every configuration, molecular spins are correlated only by dipolar interactions. The ensuing interplay between dipolar energy and anisotropy gives rise to macroscopic behaviors ranging from superparamagnetism to long-range magnetic order at temperatures below 1K.Comment: Replaced with version accepted for publication in Physical Review Letter

Life cycle assessment of conventional and advanced two-stage energy-from-waste technologies for methane production

This study integrates the Life Cycle Assessment (LCA) of thermal and biological technologies for municipal solid waste management within the context of renewable resource use for methane production. Five different scenarios are analysed for the UK, the main focus being on advanced gasification-plasma technology for Bio Substitute natural gas (Bio-SNG) production, anaerobic digestion and incineration. Firstly, a waste management perspective has been taken and a functional unit of 1 kg of waste to be disposed was used; secondly, according to an energy production perspective a functional unit of 1 MJ of renewable methane produced was considered. The first perspective demonstrates that when the current energy mix is used in the analysis (i.e. strongly based on fossil resources), processes with higher electric efficiency determine lower global warming potential (GWP). However, as the electricity mix in the UK becomes less carbon intensive and the natural gas mix increases the carbon intensity, processes with higher Bio-SNG yield are shown to achieve a lower global warming impact within the next 20 years. When the perspective of energy production is taken, more efficient technologies for renewable methane production give a lower GWP for both current and future energy mix. All other LCA indicators are also analysed and the hot spot of the anaerobic digestion process is performed