1,829 research outputs found
Regarding enumeration of molecular isomers
No full textIn this paper, a simple theoretical approach to counting of substitution isomers is described. It is based on Polya's theorem and on point groups as recently described by us [Baraldi, I.; Fiori, C.; Vanossi, D. J. Math. Chem. 1999, 25, 23-30] and extended in this paper. Several applications are developed that range from molecules without symmetry to molecules with icosahedral symmetry (Ih) The problem of the appearance of stereoisomers is also analyzed
In-plane behaviour of NFRCM-strengthened masonry modelled by means of discrete elements
No full textIn the last years, the attention to the use of eco-compatible materials and the development of sustainable solutions for structural strengthening has increased, leading to fibre-reinforced cementitious matrices (FRCM) made by natural fibres (NFRCM, de Carvalho et al. 2017).
NFRCM strengthening systems, in the same manner as FRCM ones, can be considered an alternative to fibre-reinforced-polymer (FRP) reinforcement for masonry structures, to improve the compatibility of reinforcement applied to masonry substrate (di Tommaso et al. 2017).
The numerical assessment of NFRCM and/or FRCM strengthened masonry is an active field of research and it represents a complex task, due to the complexity of both reinforcement and support materials, which can be considered as composite ones. In literature, some macro-models consider both masonry components (bricks and mortar) as a homogeneous continuum, and FRCM layers are considered as an additional equivalent continuum, with the textile fibres assumed as an embedded reinforcement of mortar matrix (Wang et al. 2017). These models have been extended to NFRCM (de Carvalho et al. 2019).
Recently, a simplified micro-model approach was proposed for diagonally loaded masonry panels reinforced with FRCM (Murgo et al. 2021), adopting a 2D FE model with one-dimensional interfaces for masonry panels, and adding a bi-directional grid of trusses for representing the reinforcement.
An updated discrete element model for simulating the in-plane behaviour of masonry walls strengthened with FRCM or NFRCM has been recently introduced by authors (Baraldi et al. 2021). This model is based on an existing discrete or rigid block model having rigid elements and nonlinear one-dimensional interfaces between them, able to represent both mortar joints and brick cracking (Baraldi et al. 2020). Such a model has been improved by considering masonry strengthened on both sides The hypothesis of perfect adhesion between the wall and reinforcement and also between the matrix and fibres of the strengthening system is assumed, in order to avoid the increase of model degrees of freedom with respect to the unreinforced masonry (URM) case. The reinforcement is modelled by means of further stiffness and strength parameters accounting for the FRCM/NFRCM geometrical and mechanical properties.
The proposed model has already turned out to successfully simulate cracking both on masonry and the external reinforcing layers and it was calibrated with respect to an existing simplified numerical model (de Carvalho et al. 2019).
In this work, the proposed discrete model is calibrated and compared with respect to several existing laboratory tests of in-plane loaded masonry panels reinforced with FRCM and NFRCM layers, in order to highlight its effectiveness and potential improvements
The Micro Level: Reconstructing the Luoyang’s Horse and Chariot Discovery
No full textIn this chapter, the Heritage Chain is applied to a specific case of heritage preservation and management in China: the “Horse and Chariot” museum . The case highlights the ability of the “Heritage Chain” to grasp a single case of heritage management with a holistic view
Between Policies and Practices: Administration Matters
No full textIn this chapter the authors outline an analytical framework which acknowledges the potential disconnection between policies and practices in cultural policies. While leaving aside the hyper-complexity of models introduced by policy implementation studies, the framework aims to immediately focus on three different levels of consistency for the analysis of cultural policies at the micro level. First, it focuses on the policy statement phase (a main topic of cultural policies studies), then on the enactment phase (a main topic of policy implementation research), and finally on the evaluation of results (partly considered by public management scholars), with the aim to recouple the three different and separated approaches
The heritage chain: Assessing the Economic Organization of the Sector
No full textIn this section the authors focus on the notion of the Heritage Chain and its possible uses through two case studies: the Horse and Chariot discovery in Luoyang, China, and the heritage system in Turkey. The Heritage Chain is to some extent another example of framework that emerged in our field research about the management of heritage in various countries. The concept refers to the set of activities taking place in the heritage sector, from protection to public access, and is derived from the notion of supply chain that was developed in the field of Industrial Organization few decades ago
"Numerical investigation of the gas concentration field during accidental release in a one vent small enclosure"
No full textNumerical investigation of the gas concentration field during accidental release in a one vent small enclosure: Effect of vent configurations
No full textCFD analysis of fast filling strategies for hydrogen tanks and their effects on key-parameters
No full textA major requirement for the filling of hydrogen tanks is the maximum gas temperature within the vessels during the process. Different filling strategies in terms of pressure and temperature of the gas injected into the cylinder and their effects on key parameters like maximum temperature, state of charge, and energy cooling demand are investigated. It is shown that pre-cooling of the gas is required but is not necessary for the whole duration of the filling. Relevant energy savings can be achieved with pre-cooling over a fraction of the time. The most convenient filling strategy from the cooling energy point of view is identified: with an almost linear pressure rise and pre-cooling in the second half of the process, a 60% reduction of the cooling energy demand is achieved compared to the case of pre-cooling for the whole filling.JRC.F.2 - Energy Conversion and Storage Technologie
Educazione scolastica e motivazione allo studio
No full textIl volume tratta delle variabili sociali che influenzano la motivazione allo studio. Presenta una ricerca sugli istituti tecnici, condotta attraverso la somministrazione di questionari ed interviste agli adolescenti e ai loro insegnanti. Il volume affronta temi quali l'importana e i modi delle scelte scolastiche, la socializzazione alla comunicazione in classe, il rapporto specifico con gli insegnanti, il disagio e la demotivazione creati dall'esperienza scolastica, i progetti degli studenti e le proposte di cambiamento. Il volume presenta così un'ampia ricognizione sul rapporto tra studenti e scuola, con particolare riferimento alla tipologia di scuole più frequentata e più varia del sistema italiano
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