Life cycle assessment (LCA) of an integrated biomass gasification combined cycle IBGCC with CO2 removal

Based on the results of previous studies, the efficiency of a Brayton/Hirn combined cycle fuelled with a clean syngas produced by means of biomass gasification and equipped with CO2 removal by chemical absorption reached 33.94%, considering also the separate CO2 compression process. The specific CO2 emission of the power plant was 178 kg/MW h. In comparison with values previously found for an integrated coal gasification combined cycle (ICGCC) with upstream CO2 chemical absorption (38–39% efficiency, 130 kg/MW h specific CO2 emissions), this configuration seems to be attractive because of the possibility of operating with a simplified scheme and because of the possibility of using biomass in a more efficient way with respect to conventional systems. In this paper, a life cycle assessment (LCA) was conducted with presenting the results on the basis of the Eco-Indicator 95 impact assessment methodology. Further, a comparison with the results previously obtained for the LCA of the ICGCC was performed in order to highlight the environmental impact of biomass production with fossil fuels utilisation. The LCA shows the important environmental advantages of biomass utilisation in terms of reduction of both greenhouse gas emissions and natural resource depletion, although an improved impact assessment methodology may better highlight the advantages due to the biomass utilisation

An integrated in silico–in vitro approach for bioprinting core–shell bioarchitectures

Biological tissues possess a high degree of structural complexity characterized by curvature and stratification of different tissue layers. Despite recent advances in in vitro technology, current engineering solutions do not comprise both of these features. In this paper, we present an integrated in silico-in vitro strategy for the design and fabrication of biological barriers with controlled curvature and architecture. Analytical and computational tools combined with advanced bioprinting methods are employed to optimize living inks for bioprinting-structured core-shell constructs based on alginate. A finite element model is used to compute the hindered diffusion and crosslinking phenomena involved in the formation of core-shell structures and to predict the width of the shell as a function of material parameters. Constructs with a solid alginate-based shell and a solid, liquid, or air core can be reproducibly printed using the workflow. As a proof of concept, epithelial cells and fibroblasts were bioprinted respectively in a liquid core (10 mg/mL Pluronic) and in a solid shell (20 mg/mL alginate plus 20 mg/mL gelatin, used for providing the cells with adhesive moieties). These constructs had a roundness of 97.6% and an average diameter of 1500 & PLUSMN;136 & mu;m. Moreover, their viability was close to monolayer controls (74.12% & PLUSMN; 22.07%) after a week in culture, and the paracellular transport was twice that of cell -free constructs, indicating cell polarization

Two new pulsating low-mass pre-white dwarfs or SX Phenix stars?*

Context. The discovery of pulsations in low-mass stars opens an opportunity for probing their interiors and to determine their evolution, by employing the tools of asteroseismology. Aims. We aim to analyze high-speed photometry of SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25 and discover brightness variabilities. In order to locate these stars in the $T_{\rm eff} - \log g$ diagram we fit optical spectra (SDSS) with synthetic non-magnetic spectra derived from model atmospheres. Methods. To carry out this study, we used the photometric data obtained by us for these stars with the 2.15m telescope at CASLEO, Argentina. We analyzed their light curves and we apply the Discrete Fourier Transform to determine the pulsation frequencies. Finally, we compare both stars in the $T_{\rm eff} - \log g$ diagram, with known two pre-white dwarfs, seven pulsating pre-ELM white dwarf stars, $\delta$ Scuti and SX Phe stars. Results. We report the discovery of pulsations in SDSSJ145847.02$+$070754.46 and SDSSJ173001.94$+$070600.25. We determine their effective temperature and surface gravity to be $T_{\rm eff}$ = 7 972 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5 and $T_{\rm eff}$ = 7 925 $\pm$ 200 K, $\log g$ = 4.25 $\pm$ 0.5, respectively. With these parameters these new pulsating low-mass stars can be identified with either ELM white dwarfs (with ~ 0.17 Mo) or more massive SX Phe stars. We identified pulsation periods of 3 278.7 and 1 633.9 s for SDSSJ145847.02$+$070754.46 and a pulsation period of 3 367.1 s for SDSSJ173001.94$+$070600.25. These two new objects together with those of Maxted et al. (2013, 2014) indicate the possible existence of a new instability domain towards the late stages of evolution of low-mass white dwarf stars, although their identification with SX Phe stars cannot be discarded.Comment: 5 pages, 5 figures, 1 table, accepted for publication in A&A

The embedded clusters DBS 77, 78, 102, and 160-161 and their link with the interstellar medium

Aims. We report a study of the global properties of some embedded clusters placed in the fourth quadrant of the Milky Way to clarify some issues related with their location into the Galaxy and their stellar formation processes. Methods. We performed BVI photometric observations in the region of DBS 77, 78, 102, 160, and 161 clusters and infrared spectroscopy in DBS 77 region. They were complemented with JHK data from VVV survey combined with 2MASS catalogue, and used mid-infrared information from GLIMPSE catalogue. We also searched for HI data from SGPS and PMN radio surveys, and previous spectroscopic stellar classification. The spectroscopic and photometric information allowed us to estimate the spectral classification of the brightest stars of each studied region. On the other hand, we used the radio data to investigate the interstellar material parameters and the continuum sources probably associated with the respective stellar components. Results. We estimated the basic physical parameters of the clusters (reddening, distance, age, and initial mass function). We searched for HII regions located near to the studied clusters and we analyzed the possible link between them. In the particular case of DBS 160-161 clusters, we identified the HI bubble B332.5-0.1-42 located around them. We found that the mechanical energy injected to the interstellar medium by the more massive stars of this couple of clusters was enough to generate the bubble.Comment: 15 pages, 14 figures, 6 tables, accepted for publication in A&

EXP-Crowd: A Gamified Crowdsourcing Framework for Explainability

The spread of AI and black-box machine learning models made it necessary to explain their behavior. Consequently, the research field of Explainable AI was born. The main objective of an Explainable AI system is to be understood by a human as the final beneficiary of the model. In our research, we frame the explainability problem from the crowds point of view and engage both users and AI researchers through a gamified crowdsourcing framework. We research whether it's possible to improve the crowds understanding of black-box models and the quality of the crowdsourced content by engaging users in a set of gamified activities through a gamified crowdsourcing framework named EXP-Crowd. While users engage in such activities, AI researchers organize and share AI- and explainability-related knowledge to educate users. We present the preliminary design of a game with a purpose (G.W.A.P.) to collect features describing real-world entities which can be used for explainability purposes. Future works will concretise and improve the current design of the framework to cover specific explainability-related needs

Detection of alien Pelophylax species in Sardinia (western Mediterranean, Italy)

Sardinian herpetofauna represent a valuable biodiversity resource in the Mediterranean Basin. Among amphibians, most of the taxa are indeed endemic to the island. In contrast, water frogs of the Pelophylax genus are considered allochthonous to Sardinia, and are traditionally assigned to the Italian pool frog (P. bergeri) and its hybridogenetic hybrid (P. kl. hispanicus). Members of this genus were recently found in certain sites in northern and southern Sardinia, and ascribed to the “ridibundus” group (the “Marsh frog” species complex). As the absence of clear phenotypic diagnostic features complicates the identification of distinct Pelophylax species, particularly European P. ridibundus, P. kurtmuelleri and several still undescribed “bedriagae” taxa, an informative diagnostic mitochondrial marker (ND3) was isolated in this work in order to detect the occurrence of distinct lineages in alien Sardinian populations. As water frogs are known to readily hybridize in the wild, two further diagnostic nuclear markers (SAI-1 and 4 microsatellite loci) were subsequently screened in order to exclude the occurrence of hybrid genotypes. According to our results, three distinct taxa were detected on the island, and assigned to P. kurtmuelleri (the Balkan frog), and two cryptic taxa of the “bedriagae” group. Nuclear markers only successfully amplified alleles diagnostic for the “ridibundus”-type (R) genome. Accordingly, we can exclude hybridization with the Italian pool frog already introduced on the island, although further studies are needed to better address the occurrence of new hybrid lineages stemming from the cross between the taxa detected in this work. As eggs and tadpoles have been detected in the field, alien populations can thus be considered successfully established in Sardinia. Our study revealed for the first time the occurrence of the alien Balkan frog in the western Mediterranean. It is worthy of note that this taxon shows a high invasion potential in mainland Europe. The establishment of alien Pelophylax populations in Sardinia may be favored by vacant niches. Nonetheless, the dry hot season could limit their expansion along rivers

High Performance Compostable Biocomposites Based on Bacterial Polyesters Suitable For Injection Molding and Blow Extrusion

This work deals with the design, preparation and characterization of composites based on Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] and lignocellulosic filler suitable for the production of compostable and biodegradable biocomposites that mimic the thermo-mechanical and processing characteristics commonly found in those polymeric materials specially designed for injection molding and blow extrusion. The best formulation in terms of processability, thermo-mechanical properties and biodegradation behavior under mature compost conditions was the biocomposite that contained 42.8 % by wt. of Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] as the major component, 5 % by wt. of lignocellulosic filler, 10 % by wt. of tributyl citrate plasticizer, 30 % by wt. of Poly(butylene adipate-co-terephthalate), 10 % by wt. of Poly(vinyl acetate), 0.2 % by wt. of Joncryl ADR-4368C a chain extender, 1 % by wt. of a primary antioxidant mix, and 1 % by wt. of nucleating agents

Effect of impurities on quasi-2D quantum antiferromagnet

We have studied the static and dynamic properties of quasi-two-dimensional quantum antiferromagnets (AF) diluted with spinless impurities using spin-wave theory and $T$-matrix approximation. We show that the spectrum of a 2D AF at long wavelengths is overdamped at arbitrary concentration of spinless impurities. The scattering leads to a new length scale $\ell/a \sim e^{\pi/4x}$, $x$ being impurity concentration and $a$ the lattice spacing, beyond which the influence of impurities on the spectrum is dominant. Although the dynamical properties are significantly modified we show that 2D is not the lower critical dimension for this problem. Thus, in low-dimensional systems with disorder the connection between static and dynamic quantities is not straightforward. Our results are in quantitative agreement with the recent Monte Carlo simulations and experimental data for $S=1/2$, S=1, and $S=5/2$. We have also proposed experiments which can further test the results of our theory.Comment: RevTeX, 3 pages, 3 figures, Proceedings of the 46 Conference on Magnetism and Magnetic Materials, Seattle 2001, to be published in J. Appl. Phy

3D extension at plate boundaries accommodated by interacting fault systems

Complex patterns of normal faults with multiple orientations and/or highly curved shapes have been traditionally explained by successive tectonic phases of 2-dimensional deformation. Alternatively, multiple fault sets have been proposed to develop simultaneously and in orthorhombic symmetry during a single phase of 3-dimensional deformation. We use analogue models of normal faults to demonstrate that, without the influence of pre-existing structures, 3D extension is preferentially accommodated by the alternate, rather than simultaneous, development of faults with different trends. By means of stress-driven interactions, 3D deformation can be partitioned into coupled systems of normal faults, which display geometries commonly observed in tectonic settings affected by interacting plate boundaries. Under radial extension, deformation is accommodated by major curvilinear grabens coupled with minor perpendicular faults, resulting in the triple junctions of grabens observed in Afar. On the other hand, the alternate development of perpendicular faults accommodates synchronous bi-directional and mutually perpendicular extension, giving the same fault pattern observed in the Barents Sea rift-shear margin