A computationally efficient method for calculating the maximum conductance of disordered networks: Application to 1-dimensional conductors

Random networks of carbon nanotubes and metallic nanowires have shown to be very useful in the production of transparent, conducting films. The electronic transport on the film depends considerably on the network properties, and on the inter-wire coupling. Here we present a simple, computationally efficient method for the calculation of conductance on random nanostructured networks. The method is implemented on metallic nanowire networks, which are described within a single-orbital tight binding Hamiltonian, and the conductance is calculated with the Kubo formula. We show how the network conductance depends on the average number of connections per wire, and on the number of wires connected to the electrodes. We also show the effect of the inter-/intra-wire hopping ratio on the conductance through the network. Furthermore, we argue that this type of calculation is easily extendable to account for the upper conductivity of realistic films spanned by tunneling networks. When compared to experimental measurements, this quantity provides a clear indication of how much room is available for improving the film conductivity.Comment: 7 pages, 5 figure

Non universality of entanglement convertibility

Recently, it has been suggested that operational properties connected to quantum computation can be alternative indicators of quantum phase transitions. In this work we systematically study these operational properties in 1D systems that present phase transitions of different orders. For this purpose, we evaluate the local convertibility between bipartite ground states. Our results suggest that the operational properties, related to non-analyticities of the entanglement spectrum, are good detectors of explicit symmetries of the model, but not necessarily of phase transitions. We also show that thermodynamically equivalent phases, such as Luttinger liquids, may display different convertibility properties depending on the underlying microscopic model.Comment: 5 pages + references, 4 figures - improved versio

Insight into the high-pressure CO2 pre-treatment of sugarcane bagasse for a delivery of upgradable sugars

ABSTRACT: This work provides an insight into sugarcane bagasse pre-treatment carried out with greener and more sustainable CO2/H2O system. Temperatures and residence times at a fixed initial CO2 pressure were studied to verify their effects on pre-treatment efficiency with regard to the chemical composition of both water-soluble and water-insoluble fractions as well as to the susceptibility of the latter to enzymatic hydrolysis at high total solids. Also, trends in enzymatic hydrolysis were analysed in function of biomass crystallinity. This work provides an integrated approach in the analysis of upgradable sugars that are released as a result of pre-treatment and enzymatic hydrolysis. At optimal pre-treatment conditions, 17.2 g.L-1 sugars were released in the water-soluble fraction mainly as pentoses in monomeric and oligomeric forms. The enzymatic hydrolysis of solids produced at these pre-treatment conditions gave 76.8 g.L-1 glucose in the substrate hydrolysate. The overall sugar yield delivered in both pre-treatment and enzymatic hydrolysis was 73,9 mol%. These results were compared to the chemical effect of hydrothermal and/or physico-chemical effects of N-2-aided hydrothermal processes and showed that the greener processing of biomass pre-treatment with CO2 is advantageous for the integrated valorisation of industrial residues and delivery of upgradable sugars within the biorefinery concept.info:eu-repo/semantics/publishedVersio

Phenolic profile and antioxidant activity of commercial grape juices from the São Francisco Valley, Northeastern of Brazil.

In recent years, The Sub-middle region of the São Francisco Valley (SFV), located in the Northeast of Brazil, has invested in the production of grape juice from new Brazilian varieties developed for preparation of high quality juices, such as Isabel Precoce (Vitis labrusca L.) and hybrids (Vitis labrusca L. x Vitis vinifera L.) BRS Violeta, BRS Cora and BRS Magna (Lima et al., 2014). Grape juice in this region have been highlighted by the good bioactive content, high antioxidant activity associated with phenolic compounds and to promote anti-inflammatory activity in consumers (Toscano et al., 2015)

Anthocyanin composition of young red wine cv. Ruby Cabernet and Syrah: effect of time and storage conditions.

The aim of this study was to evaluate the evolution of anthocyanins in red wines for 12 months of storage in bottles in two different conditions. The wine samples cv. Ruby Cabernet and cv. Syrah (Vitis vinifera L.) used for this study were produced in the Sub-middle São Francisco Valley, in the Northeast Region of Brazil, during the 2013 harvest

Anthocyanin composition of young red wine cv. Ruby Cabernet and Syrah: effect of time and storage conditions.

The aim of this study was to evaluate the evolution of anthocyanins in red wines for 12 months of storage in bottles in two different conditions. The wine samples cv. Ruby Cabernet and cv. Syrah (Vitis vinifera L.) used for this study were produced in the Sub-middle São Francisco Valley, in the Northeast Region of Brazil, during the 2013 harvest

Thiophene- and carbazole-substituted N-Methyl-Fulleropyrrolidine acceptors in PffBT4T-2OD based solar cells

The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2′;5′,2″;5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) as donor and C60 or C70 fulleropyrrolidines as acceptors. The photovoltaic performance clearly depended on the molecular structure of the fulleropyrrolidine substituents although no direct correlation with the surface morphology of the photoactive layer, as determined by atomic force microscopy, could be established. Although some fulleropyrrolidines possess favorable lowest unoccupied molecular orbital levels, when compared to the standard PC71BM, they originated OPV cells with inferior efficiencies than PC71BM-based reference cells. Fulleropyrrolidines based on C60 produced, in general, better devices than those based on C70, and we attribute this observation to the detrimental effect of the structural and energetic disorder that is present in the regioisomer mixtures of C70-based fullerenes, but absent in the C60-based fullerenes. These results provide new additional knowledge on the effect of the fullerene functionalization on the efficiency of organic solar cells.This work was financially supported by: Base Funding — UIDB/00511/2020 of the Laboratory forProcess Engineering, Environment, Biotechnology and Energy — LEPABE — funded by national funds through theFCT/MCTES (PIDDAC). This work was partially funded within the scope of the project i3N, UIDB/50025/2020 & UIDP/50025/2020, financed by national funds through the FCT/MEC. Thanks are also due to FCT/MEC for thefinancial support to QOPNA (FCT UID/QUI/00062/2019), CICECO-Aveiro Institute of Materials (UIDB/50011/2020& UIDP/50011/2020), CQE (FCT UIDB/00100/2020), and CIQUP (FCT UID/QUI/UI0081/2019) research units, throughnational funds and where applicable co-financed by the FEDER, within the PT2020 Partnership Agreement. H.G.thanks Fundação para a Ciência e a Tecnologia (FCT) for his PhD scholarship (SFRH/BD/103009/2014). The researchcontracts of F.F. (REF. -168-89-ARH/2018) is funded by national funds (OE), through FCT—Fundação para aCiência e Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of article 23,of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. M.M.F. acknowledges also supportfrom FCT under the project IF/00894/2015