1,721,398 research outputs found

    Partial hydrogenation of a C18:3-rich FAME mixture over Pd/C

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    The study focuses on the partial hydrogenation of a C18:3-rich FAME mixture (a-linolenate/linoleate: ~3.5:1 mol/mol) taken as a model of FAME materials obtainable from alternative non-edible oils deriving from non-food biomass, which are suitable feedstocks for 2nd generation biodiesel. High C18:1 yield and selectivity required an accurate control of reaction time and temperature because of stearate generation through consecutive reactions C18:3/C18:2/C18:1/C18:0. In n-heptane, under mild conditions (50 °C, 0.1 MPa H2, 1 h), the FAME mixture was converted over Pd(5%)/C into C18:1 selectively (97.8%), with high yield (81.1%). The final mixture was C18:3-free (0.1%) and showed a low content of stearate (2.0%). Also the C18:2 component was markedly reduced (21.5%/16.7%). The content of trans-C18:1- monoenes was 39.0%. A lower content of trans-C18:1 (16.4%) was attained at 0 °C (1.5 h). Under the latter conditions, stearate and C18:3 in the final product were, respectively, 3.3% and 1.5%. Remarkably, Pd/C can act as a tunable catalyst being able to promote effectively the full hydrogenation of the FAME mixture to stearate under uncommon very mild conditions (0 °C, 0.1 MPa) within a relatively short time (6 h). Under solventless conditions or in polar solvents (MeOH, THF, dimethyl carbonate), hydrogenation was slower and less selective than in n-heptane

    Traditions and Practices in Fifteenth- and Sixteenth-Century Sacred Polyphony: The Use of Solo Voices with Instrumental Accompaniment

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    Indagine sulla consuetudine esecutiva della polifonia sacra quattro-cinquecentesca con voci assolo e accompagnamento strumentale. Attraverso la documentazione d’archivio riguardante la pratica di esecuzione solistica della polifonia ‘a cappella’ nel Cinquecento si traccia una linea che collega, a ritroso, le composizioni solistiche primo-secentesche di Lodovico da Viadana a quelle di tradizione quattrocentesca. Infine si dà una spiegazione per la scomparsa della consuetudine solistica dalle pratiche compositive (ma non da quelle esecutive) a partire dal primo Cinquecento

    Nicola Turi, <i>Declinazioni del canone americano in Italia tra gli anni Quaranta e Sessanta</i>

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    Review of the book Declinazioni del canone americano in Italia tra gli anni Quaranta e Sessanta

    Per una nuova storiografia della musica sacra da chiesa in epoca pre-napoleonica

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    proposta per la valorizzazione del ruolo del consumo quotidiano, della consuetudine e dell'economia della musica nella moderna storiografia musicologic

    Ecclesiasticarum cantionum quatuor vocum (1576)

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    edizione critica delle Ecclesiasticarum cantionum quatuor vocum (1576) di Andrea Gabriel

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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