Search results for " material"
showing 10 items of 17428 documents
High-Performance Lead-Acid Batteries Enabled by Pb and PbO2 Nanostructured Electrodes: Effect of Operating Temperature
2021
Lead-acid batteries are now widely used for energy storage, as result of an established and reliable technology. In the last decade, several studies have been carried out to improve the performance of this type of batteries, with the main objective to replace the conventional plates with innovative electrodes with improved stability, increased capacity and a larger active surface. Such studies ultimately aim to improve the kinetics of electrochemical conversion reactions at the electrode-solution interface and to guarantee a good electrical continuity during the repeated charge/discharge cycles. To achieve these objectives, our contribution focuses on the employment of nanostructured electr…
Thermo-Mechanical Behaviour of Flax-Fibre Reinforced Epoxy Laminates for Industrial Applications
2015
The present work describes the experimental mechanical characterisation of a natural flax fibre reinforced epoxy polymer composite. A commercial plain woven quasi-unidirectional flax fabric with spun-twisted yarns is employed in particular, as well as unidirectional composite panels manufactured with three techniques: hand-lay-up, vacuum bagging and resin infusion. The stiffness and strength behaviours are investigated under both monotonic and low-cycle fatigue loadings. The analysed material has, in particular, shown a typical bilinear behaviour under pure traction, with a knee yield point occurring at a rather low stress value, after which the material tensile stiffness is significantly r…
Effect of NaOH Treatment on Properties of Phoenix Sp. Fiber
2016
The aim of this paper is to investigate the effect of an alkali treatment on physical, chemical, mechanical, and morphological properties of Phoenix Sp. fibers. The use of natural fibers as reinforcement in polymer composites requires a deep investigation to understand their behavior and which treatment is more appropriate to improve the quality of the untreated material. For this reason, fibers were extracted from the petioles of the Phoenix Sp. plant and they were treated with NaOH solution in different weight concentrations (5%, 10%, and 15%). The mechanical behavior was investigated through tensile test on single fiber at different gauge length (20 mm, 30 mm, 40 mm, 50 mm, and 60 mm). C…
Effect of Core–Shell Rubber Nanoparticles on the Mechanical Properties of Epoxy and Epoxy-Based CFRP
2022
This research was funded by M-Era.Net project MERF “Matrix for carbon reinforced epoxy laminates with reduced flammability” grant No. 1.1.1.5/ERANET/20/04 from the Latvian State Education Development Agency and M-Era.Net project “EPIC—European Partnership for Improved Composites“ funded by grant No. TH06020001. A.S., K.S. and A.Z. are grateful to funding received from the European Union Horizon 2020 Framework program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
Lògica materialista de Galvano della Volpe [Pròleg]
2004
Enfront del vell marxisme antropocèntric, i al capdavall escatològic, que circulava per les Facultats del país a principi de la dècada dels seixanta, i del qual es nodrien tants estudiants d'aleshores, guanyen terreny aquests darrers anys uns altres corrents marxistes, no tan recents com hom podria pensar, i que marxen per altres dreceres: a la preocupació humanista oposen la direcció epistemològica de llurs reflexions.
Understanding the White-Emitting CaMoO4 Co-Doped Eu3+, Tb3+, and Tm3+ Phosphor through Experiment and Computation
2019
In this article, the synthesis by means of the spray pyrolysis method, of the CaMoO4 and rare-earth cation (RE3+)-doped CaMoO4:xRE3+ (RE3+ = Eu3+, Tb3+, and Tm3+; and x = 1, 2, and 4% mol) compounds, is presented. The as-synthesized samples were characterized using X-ray diffraction, Rietveld refinement, field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and photoluminescence (PL) spectroscopy. To complement and rationalize the experimental results, first-principles calculations, at the density functional theory level, have been performed to analyze the band structure and density of states. In addition, a theoretical method based on the calculations of surface energie…
Nuove forme ed espressioni dell'architettura in terra cruda
2008
Acciaio, vetro, calcestruzzo, materie plastiche di ogni tipo sono considerati oggi, nel mondo industrializzato, materiali essenziali per la costruzione delle cosiddette “case-astronavi” realizzate nelle aree più disparate della terra, in modo selvaggio ed indiscriminato, prive di qualsiasi relazione con il contesto; edifici energivori, pressoché simili tra loro, che affidano il loro funzionamento ed il raggiungimento delle condizioni di benessere all’interno degli ambienti ad impianti tecnici sempre più sofisticati e sempre più dannosi per l’ecosistema, con ripercussioni negative sulla qualità della vita. Immagine di uno status symbol al quale oggi è sempre più difficile rinunciare. Consegu…
"Ci sono più cose in cielo e in terra..." Due metodologie diverse per investigare il passato: il Castello Nuovo di Sciacca tra storia e archeologia
2012
La storia di Sciacca e del Castello Nuovo, ricostruita sulle fonti documentarie, riceve nuova luce dalle indagini condotte dalla Soprintendenza di Agrigento nel butto del castello, che ha restituito importanti testimonianze di cultura materiale. Il contributo, attraverso la lettura sinottica dei dati archeologici ed archivistici, offre un quadro della vita quotidiana al castello tra il XIV ed il XVI secolo, quando Sciacca con il suo caricatore riveste un ruolo di primo piano nel commercio mediterraneo. The history of Sciacca and Castello Nuovo documented by archival sources and further enriched by the researches conducted by Soprintendenza of Agrigento is in the dump of the castle, which ha…
2-Methylresorcinarene: a very high packing coefficient in a mono-anion based dimeric capsule and the X-ray crystal structure of the tetra-anion
2016
Mono- and tetra-deprotonated 2-methylresorcinarene anions (1 and 2) as their trans-1,4-diammoniumcyclohexane (TDAC)2+ inclusion complexes are reported. The mono-anion forms a fully closed dimeric capsule [1·H2O·MeOH]22− with a cavity volume of 165 Å3 and (TDAC)2+ as the guest with an extremely high packing coefficient, PC = 84.2%, while the tetra-anion forms a close-packed structure with two structurally isomeric tetra-anions 2a and 2b with a 50 : 50 ratio in the crystal lattice. peerReviewed
Spin Crossover in Fe(II)–M(II) Cyanoheterobimetallic Frameworks (M = Ni, Pd, Pt) with 2-Substituted Pyrazines
2016
Discovery of spin-crossover (SCO) behavior in the family of Fe(II)-based Hofmann clathrates has led to a "new rush" in the field of bistable molecular materials. To date this class of SCO complexes is represented by several dozens of individual compounds, and areas of their potential application steadily increase. Starting from Fe(2+), square planar tetracyanometalates M(II)(CN)4(2-) (M(II) = Ni, Pd, Pt) and 2-substituted pyrazines Xpz (X = Cl, Me, I) as coligands we obtained a series of nine new Hofmann clathrate-like coordination frameworks. X-ray diffraction reveals that in these complexes Fe(II) ion has a pseudo-octahedral coordination environment supported by four μ4-tetracyanometallat…