Alternative route for the synthesis of Lanthanum Strontium Titanate as SOFC Ni-free anode material

Among the perovskite structures, lanthanum-doped strontium titanates have attracted a lot of attention as possible candidates for SOFC Ni-free anodes. In particular the composition LaxSr1-(3x/2)TiO3 with x = 0.4 (LST) was recently considered for its tolerance to redox cycles and sufficiently high conductivities values. In this work an extensive study on the synthesis of LST powders with low-cost and easy-scalable methods is reported. The solid state and chemical synthesis as well as a combination of solution-solid state synthesis were considered. The influence of either the nature of the precursors (oxides, carbonates or nitrates) and the calcination temperature (from 500 to 1350?C) onto the perovskite formation was evaluated. The as-synthesized powders were morphologically, structurally and chemically characterized. The Pechini method leads to pure perovskite phase at 700?C for 1h, but it allows the production of only few grams of powder for each batch. On the other hand the solid state synthesis is a more up-scalable method but the phase can be obtained only at 1100?C for 1h. In addition the high reactivity of the lanthanum towards the humidity leads to a difficult control of the system stoichiometry and therefore of the final phase composition. An alternative solution-solid state synthesis was considered to produce batch of 100g of LST powders with good phase purity and in relatively mild conditions. The pure perovskite phase with the correct stoichiometry was obtained starting from the La and Sr nitrate aqueous solutions, highly reactive TiO2 followed by freeze-drying and calcination at 900?C for 1

RNA sequencing and de novo assembly of the digestive gland transcriptome in Mytilus galloprovincialis fed with toxinogenic and non-toxic strains of Alexandrium minutum

Background The Mediterranean mussel Mytilus galloprovincialis is marine bivalve with a relevant commercial importance as well as a key sentinel organism for the biomonitoring of environmental pollution. Here we report the RNA sequencing of the mussel digestive gland, performed with the aim: a) to produce a high quality de novo transcriptome assembly, thus improving the genetic and molecular knowledge of this organism b) to provide an initial assessment of the response to paralytic shellfish poisoning (PSP) on a molecular level, in order to identify possible molecular markers of toxin accumulation. Results The comprehensive de novo assembly and annotation of the transcriptome yielded a collection of 12,079 non-redundant consensus sequences with an average length of 958 bp, with a high percentage of full-length transcripts. The whole-transcriptome gene expression study indicated that the accumulation of paralytic toxins produced by the dinoflagellate Alexandrium minutum over a time span of 5 days scarcely affected gene expression, but the results need further validation with a greater number of biological samples and naturally contaminated specimens. Conclusion The digestive gland reference transcriptome we produced significantly improves the data collected from previous sequencing efforts and provides a basic resource for expanding functional genomics investigations in M. galloprovincialis. Although not conclusive, the results of the RNA-seq gene expression analysis support the classification of mussels as bivalves refractory to paralytic shellfish poisoning and point out that the identification molecular biomarkers of PSP in the digestive gland of this organism is problematic

Design of a kite controller for airborne wind energy

Airborne wind energy is a field of technology being developed to make use of the vast, renewable wind power resource which is above the reach of traditional wind turbines, without the need for a large tower. Much analytical research has been undertaken in recent years to better understand the problem space. However, there are relatively few working systems that demonstrate their functioning and can be compared with simulations and theory. Off-grid power systems still rely heavily on diesel generators, so devices that tap renewable energy sources with similar ease of deployment and lower cost of energy would help this sector to reduce its reliance on expensive, polluting, fossil fuels. The development of these systems is often performed by teams with business interests leaving little open access content available regarding the design process of such devices or the data that they provide. A kite control pod has been designed for the remote control of a standard kitesurfing kite and a prototype has been demonstrated stably flying such a kite on a fixed length tether. This pod and kite would be tethered to a winch and as the kite flies across the wind, the lift force generated is applied to the winch which is reeled out and electrical power generated. Once fully extended, the tether would be reeled in with the kite de-powered, using some of the generated energy, stored in a battery. This system can then be used as a test bed for the further development of a compact, autonomous, airborne wind energy system for off-grid applications

Plasmonically Enhanced Reflectance of Heat Radiation from Low-Bandgap Semiconductor Microinclusions

Increased reflectance from the inclusion of highly scattering particles at low volume fractions in an insulating dielectric offers a promising way to reduce radiative thermal losses at high temperatures. Here, we investigate plasmonic resonance driven enhanced scattering from microinclusions of low-bandgap semiconductors (InP, Si, Ge, PbS, InAs and Te) in an insulating composite to tailor its infrared reflectance for minimizing thermal losses from radiative transfer. To this end, we compute the spectral properties of the microcomposites using Monte Carlo modeling and compare them with results from Fresnel equations. The role of particle size-dependent Mie scattering and absorption efficiencies, and, scattering anisotropy are studied to identify the optimal microinclusion size and material parameters for maximizing the reflectance of the thermal radiation. For composites with Si and Ge microinclusions we obtain reflectance efficiencies of 57 - 65% for the incident blackbody radiation from sources at temperatures in the range 400 - 1600 {\deg}C. Furthermore, we observe a broadbanding of the reflectance spectra from the plasmonic resonances due to charge carriers generated from defect states within the semiconductor bandgap. Our results thus open up the possibility of developing efficient high-temperature thermal insulators through use of the low-bandgap semiconductor microinclusions in insulating dielectrics.Comment: Main article (8 Figures and 2 Tables) + Supporting Information (8 Figures

Hydroponic culture of Gladiolus tristis: Application of paclobutrazol for flowering and height control

Gladiolus tristis (ever-flowering gladiolus) was tested for its potential as a flowering potted plant, using the growth retardant paclobutrazol. The treatments included a control, 2, 4, 8 and 16 mg activeingredient (a.i.) per pot and were applied when the longest leaves reached 15 cm. All treatments reduced perpendicular leaf height. Inflorescence heights were significantly affected by paclobutrazol.The flower spikes of plants treated with 2, 4 and 8 mg a.i. per pot were only marginally shorter than the control, while the height of plants treated with 16 mg was significantly reduced. All plants reached firstflower anthesis within a month from 22 weeks after planting. Flowering was staggered throughout the month, from the control through to plants treated with 16 mg a.i., with the control flowering from 166days after planting, gradually increasing to 178 for 2 mg, 181 for 4 mg, 183 for 8 mg, and 186 for 16 mg a.i./pot. The average number of flowers produced per pot significantly dropped with increasing strengthof a.i. applied. The control produced an average of three flowers while plants treated with 16 mg a.i produced less than one

Administration of hepatic stimulatory substance alone or with other liver growth factors does not ameliorate acetaminophen‐induced liver failure

Sixty‐two beagle dogs were given three doses of acetaminophen over a period of 24 hr in a fulminant liver failure model that is 70% lethal in 72 hr. Treatment of the animals with hepatic stimulatory substance alone or in a mixture with insulin, transforming growth factor‐α and insulin‐like growth factor II had no effect on mortality. Evidence of maximum regeneration with a mitotic index 20 to 25 times resting was the same in treated and untreated animals. Similarly, the biochemical and hematological indexes of liver injury were unaffected by therapy. These studies illustrate the futility of treating fulminant liver failure with exogenous growth factors that apparently are already present in large amounts in the natural response to liver injury. The results suggest that on‐going liver injury by mechanisms other than lack of growth factors is the central problem of fulminant liver failure. If so, provision of regeneration‐stimulating substance is an inappropriate therapeutic strategy. (HEPATOLOGY 1993;17:429–433.) Copyright © 1993 American Association for the Study of Liver Disease

Studio dei protocolli MultiPath nell'Internet allo stato dell'arte

Nel mondo interconnesso di oggi, una comunicazione affidabile ed efficiente è fondamentale per il trasferimento dei dati e per il miglioramento dell’esperienza dell’utente. L’affidamento convenzionale alla comunicazione a percorso singolo, tuttavia, spesso deve affrontare problematiche come la congestione dei percorsi, il degradamento del segnale e la vulnerabilità alle interruzioni. Per superare queste limitazioni e ottenere nuove possibilità, i ricercatori hanno rivolto la loro attenzione alla comunicazione MultiPath, un paradigma che sfrutta la potenza di più percorsi sumultanei per migliorare l’affidabilità e le prestazioni della rete. In questo documento andremo ad analizzare il protocollo attualmente più utilizzato, il MultiPathTCP (MPTCP), assieme ad altri protocolli più recenti ed andremo a metterli a confronto per verificare la prestanza delle nuove soluzioni rispetto a quella più diffusa

Discalculia: includere attraverso la didattica in classe

Perché uno studente, con quoziente intellettivo nella media, che ha buoni voti in tutte le materie, colleziona insuccessi in matematica? Si può trattare di difficoltà di apprendimento passeggere su un dato argomento, può essere un atteggiamento negativo nei confronti della materia o può trattarsi di discalculia. L'insegnante di matematica deve essere preparato ad individuare le possibili cause dell'insuccesso scolastico degli studenti e ad attuare le strategie didattiche che migliorino il più possibile il suo percorso scolastico. Nel mio elaborato ho riportato una sintesi delle leggi che hanno condotto la scuola italiana ad orientarsi in una prospettiva sempre più inclusiva. In particolare ho riportato la legge 170 del 2010, la prima che definisce i disturbi dell'apprendimento, e la direttiva Bes del 2012, che amplia ancora di più l'area delle problematiche scolastiche. Partendo da una distinzione tra disturbo e difficoltà nell'apprendimento, ho trattato poi in particolare la discalculia, dal punto di vista didattico e riportando le sue definizioni nel corso del tempo. Tra le difficoltà ho citato invece la Matofobia o Math Anxiety. Una paura della matematica ereditata, un'eredità trasmessa però attraverso l'ambiente in cui si cresce e non dai geni. Infine ipotizzando delle lezioni in una classe di seconda superiore in cui sono presenti studenti con discalculia, ho realizzato un'unità didattica dal titolo "Le rette nel piano cartesiano". Per la sua realizzazione ho pensato all'utilizzo del software geogebra e del lavoro in gruppi, per promuovere l'apprendimento attraverso la scoperta e il ragionamento logico, piuttosto che la memorizzazione di formule e la loro mera applicazione. Ho concluso il mio elaborato riportando delle riflessioni su come i docenti si attivano in presenza di uno studente con certificazione di dsa e sul rapporto tra scuola e famiglie, riflessioni tratte da alcune interviste fatte ai referenti per i dsa in diverse scuole della Romagna