Competition of the connectivity with the local and the global order in polymer melts and crystals

The competition between the connectivity and the local or global order in model fully-flexible chain molecules is investigated by molecular-dynamics simulations. States with both missing (melts) and high (crystal) global order are considered. Local order is characterized within the first coordination shell (FCS) of a tagged monomer and found to be lower than in atomic systems in both melt and crystal. The role played by the bonds linking the tagged monomer to FCS monomers (radial bonds), and the bonds linking two FCS monomers (shell bonds) is investigated. The detailed analysis in terms of Steinhardt's orientation order parameters Q_l (l = 2 - 10) reveals that increasing the number of shell bonds decreases the FCS order in both melt and crystal. Differently, the FCS arrangements organize the radial bonds. Even if the molecular chains are fully flexible, the distribution of the angle formed by adjacent radial bonds exhibits sharp contributions at the characteristic angles {\theta} = 70{\deg}, 122{\deg}, 180{\deg}. The fractions of adjacent radial bonds with {\theta} = 122{\deg}, 180{\deg} are enhanced by the global order of the crystal, whereas the fraction with 70{\deg} < {\theta} < 110{\deg} is nearly unaffected by the crystallization. Kink defects, i.e. large lateral displacements of the chains, are evidenced in the crystalline state.Comment: J. Chem. Phys. in pres

Seismic Vulnerability Assessment of Priority Cultural Heritage Structures in the Philippines

At the end of 2013 two catastrophic events occurred in the Philippines: the M 7.2 earthquake in Bohol and the strongest ever recorded Typhoon Haiyan, causing destruction across the islands of Cebu, Bohol and the Visayas region. These events raised the need to carry out a multi-hazard risk assessment of heritage buildings, many of which were irretrievably lost in the disasters. Philippines’ Department of Tourism engaged ARS Progetti S.P.A., Rome, Italy, and the Center for Conservation of Cultural Property and Environment in the Tropics (CCCPET), University of Sto. Tomas, Manila, to undertake the “Assessment of the Multi-Hazard Vulnerability of Priority Cultural Heritage Structures in the Philippines”, with experts from University College London, UK, and De La Salle University. The main objective of the project was to reduce the vulnerability of cultural heritage structures to multiple natural hazards, including earthquake, typhoon, flood, by: (i) prioritizing of specific structures based on hazard maps and historical records; (ii) assessing their vulnerability; and (iii) recommending options to mitigate the impacts on them. The paper presents the methodology introduced to determine the seismic risk these heritage buildings are exposed to. All the selected cultural heritage structures are under the jurisdiction of the National Museum Commission of Philippines and of the National Commission for Culture and Arts

Aret\ue9 storia e tecniche costruttive di un\u2019innovativa barca da regata

Le imbarcazioni a vela da regata costituiscono un ottimo banco di prova per la costruzione e sperimentazione di pezzi e materiali con contenuti importanti di tecnologia e innovazione In questo ambito si \ue8 sviluppato il progetto 1001Vela Cup che ha lo scopo di far progettare, costruire e sperimentare a studenti universitari un\u2019imbarcazione a vela di 4,60 metri Particolarmente innovativo \ue8 il nuovo scafo del team padovano, che \ue8 stato costruito interamente in fibra di lino e legno di balsa, materiali che sono stati uniti insieme attraverso le tecniche costruttive dei bio-composit

Architettura_Energia. La costruzione dal dettaglio alla città.

Il settore dell'edilizia, secondo gli studi attuali, rappresenta il comparto delle attività umane e maggiore incidenza sull'ecobilancio del pianeta, seguito dal settore dei trasporti e quello industriale-produttivo. L'interesse verso questi temi è enfatizzato dal contesto urbano in cui il sommarsi di fattori critici sottolinea l'urgenza e la multidisciplinarità dello sviluppo energetico sostenibile sia dal punto di vista ambientale sia da quallo socio-economico

A bio-composite racing sailboat: Materials selection, design, manufacturing and sailing

Bio-composites represent an interesting solution for replacing fiber-glass in yachts, with the aim of increasing the environmental sustainability of the nautical sector. This replacement is already occurring in several industrial sectors, from building to automotive. However, the nautical field seems reluctant in embracing this innovation; reasons might be found in the lack of technical references describing the bio-composite boat construction methods and the durability of the yacht within time. The production of a 4.6 m flax-epoxy and balsa wood racing sailboat is here described. The final aim of the paper is providing boat designers and manufacturers with the methods to design and construct a bio-composite craft. Tensile tests were performed on several specimens to obtain the mechanical properties of different fiber batches. Resin absorption tests were conducted to select the natural core and surface treatment, to minimize the final weight of the sandwich laminate. Finally, a specific multi-step infusion technique was developed to manufacture the hull and deck, limiting the boat final weight to 65 kg. After four years from the launch, the boat neither shows structural failure nor damage. This is considered a good test and indicates interesting perspectives for the applicability of bio-composites into the nautical recreational field

Xrn1 influence on gene transcription results from the combination of general effects on elongating RNA pol II and gene-specific chromatin configuration

mRNA homoeostasis is favoured by crosstalk between transcription and degradation machineries. Both the Ccr4-Not and the Xrn1-decaysome complexes have been described to influence transcription. While Ccr4-Not has been shown to directly stimulate transcription elongation, the information available on how Xrn1 influences transcription is scarce and contradictory. In this study we have addressed this issue by mapping RNA polymerase II (RNA pol II) at high resolution, using CRAC and BioGRO-seq techniques in Saccharomyces cerevisiae. We found significant effects of Xrn1 perturbation on RNA pol II profiles across the genome. RNA pol II profiles at 5' exhibited significant alterations that were compatible with decreased elongation rates in the absence of Xrn1. Nucleosome mapping detected altered chromatin configuration in the gene bodies. We also detected accumulation of RNA pol II shortly upstream of polyadenylation sites by CRAC, although not by BioGRO-seq, suggesting higher frequency of backtracking before pre-mRNA cleavage. This phenomenon was particularly linked to genes with poorly positioned nucleosomes at this position. Accumulation of RNA pol II at 3' was also detected in other mRNA decay mutants. According to these and other pieces of evidence, Xrn1 seems to influence transcription elongation at least in two ways: by directly favouring elongation rates and by a more general mechanism that connects mRNA decay to late elongation

Sfide per una dimensione sostenibile del costruire. Contributi sull'uso dell'energia in architettura.

Il raggiungimento di una dimensione sostenibile in un progetto di architettura pu\uf2 essere considerata una vera e propria sfida: non solo tecnica, ma anche culturale. Una sfida in cui si intrecciano una molteplicit\ue0 di questioni legate alle modalit\ue0 del progetto, all\u2019uso dei materiali e della tecnologia in una continua variazione di scala che interessa tanto il pi\uf9 piccolo edificio quanto la pi\uf9 grande citt\ue0. Tuttavia, tra le numerose variabili in gioco sembra esserci una costante, l\u2019uso dell\u2019energia che, assumendo diverse forme, diviene elemento ricorrente coinvolgendo trasversalmente ogni aspetto legato all\u2019azione del costruire. Esito di un lavoro di ricerca in ambito internazionale, questo libro raccoglie una pluralit\ue0 di visioni, di riflessioni compiute da diversi autori, appartenenti a differenti realt\ue0 accademiche e professionali, intorno al tema dell\u2019energia e ai diversi modi di tradurla in materiali, tecnologie, progetti per architetture sostenibili