Canonical Expressions of Algebraic Curvature Tensors

Algebraic curvature tensors can be expressed in a variety of ways, and it is helpful to develop invariants that can distinguish between them. One potential invariant is the signature of R, which could be defined in a number of ways, similar to the signature of an inner product. This paper shows that any algebraic curvature tensor defined on a vector space V with dim(V) = n can be expressed using only canonical algebraic curvature tensors from forms with rank k or higher for any k in {2,...,n}, and that such an expression is not unique, eliminating some possibilities for what one might define the signature of R to be. We also provide bounds on the minimum number of algebraic curvature tensors of rank k needed to express any given R

Exploring the transient Universe in the multi-messenger Astronomy era

Supernovae (SNe) can be studied through the analysis of the different messengers they produce (GWs, neutrinos, high energy particles and radiation in the optical regime). In the last decade new instruments were developed to detect neutrinos, GWs and high energy cosmic rays: IceCube (Michaely and Perets, 2018); CTA telescope (Acero et al., 2017); LIGO and VIRGO (Abbott et al., 2018). Thus, the analysis of the signal from neutrinos, relativistic cosmic particles and GW can be an important piece of the puzzle in our understanding the SN physics. Within the presented scientific framework I analysed the SUDARE survey data, this is to acquire a consolidated and well defined method for the SN search and to study the detected SN sample using a statistical approach (I measured the SN rate as a function of cosmic time and parent galaxy parameters: mass, color and sSFR) in order to constrain SN progenitor models. The results of SUDARE survey data analysis open a discussion on how to improve the SN search with next generation of synoptic surveys; thus, I simulate a SN search as it would happen within LSST to analyse how the SN statistics and classification will be improved. Moreover, I exploit the method for SN search to study the impact of the new synoptic surveys in the detection of unknown transients, and eventually to study transients discovered using different messengers, to detect their optical counterpart

Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

The present review article describes in detail the state-of-the-art of organic-inorganic hybrid materials based on polyimide/silica components. The article is divided in three parts. In the first the basic processing route for the preparation of these systems is described, i.e. the sol-gel technique, along with the strategies developed to control the final morphology. In the second part the curing characteristics, the dynamic-mechanical and the mechanical and fracture properties of hybrids with different morphologies are reviewed. Finally, the more technologically relevant applications devised for these high performance materials are discussed

Close to the volcan. Knowledge, conservation and enhancement of a Vesuvian vernacular heritage

[EN] In the area surrounding the slopes of the volcano, a historical network of rural architecture created by the known fertility of the Vesuvian soil can be identified. The terrain, rich in minerals due to the pyroclastic nature of the site, has since Roman times favoured the construction of agricultural structures, more or less concentrated in areas where the impervious nature of the soil allowed a profitable settlement for cultivation. The network of such examples of vernacular architecture, located within the boundaries of the Vesuvius National Park, is still visible today, albeit fragmented and in a state of abandonment. An ongoing research has made it possible to carry out an initial rigorous survey. These buildings are expression of distribution criteria in line with their function and represent the close relationship between settlement typology and territory. This peculiarity is strongly reflected in the constructive techniques and also represents the material evidence of a particular building savoir-faire passed down through the centuries. Materials taken from the site (e.g. lavas, lava foam, lapilli, pumice, etc.) are used and although there is no accurate quarrying of the stone, there is the technique 'a cantieri' with a strong mortar as a binder. The typology is diversified: from the small presidio to the building arranged on two levels, sometimes turreted, depending on the production and cultivation commitment. Unlike the traditional farms (masserie) located further down the valley, which have already been the subject of a considerable historiography, these cases of rural architecture located further up the slope have never been the subject of systematic survey. The contribution aims to focus on this almost unpublished heritage and to illustrate a methodology of integrated knowledge linked to the peculiarities of the volcanic site. The conservation of these vernacular architectures, in fact, plays a central role in the reading and understanding of the multidimensional values of the Vesuvius-Bay of Naples cultural landscape.[IT] Nell'area circostante le pendici del vulcano è individuabile un reticolo storico di architettura rurale creato dalla nota fertilità del suolo vesuviano. Il terreno, ricco di minerali per la natura piroclastica del sito, ha favorito fin dall'epoca romana la costruzione di strutture agricole, più o meno concentrate in aree dove la natura impervia del suolo consentiva un proficuo insediamento per la coltivazione. La rete di tali esempi di architettura vernacolare, situata entro i confini del Parco Nazionale del Vesuvio, è ancora oggi visibile, seppur frammentata e in stato di abbandono. Una ricerca in corso ha permesso di effettuare una prima rigorosa indagine. Tali edifici sono espressione di criteri distributivi coerenti con la loro funzione e rappresentano lo stretto rapporto tra tipologia insediativa e territorio. Questa particolarità si riflette fortemente nelle tecniche costruttive e rappresenta anche la testimonianza materiale di un particolare savoir-faire edilizio tramandato nei secoli. Vengono utilizzati materiali prelevati dal sito (es. lave, schiuma lavica, lapilli, pomice, ecc.) e sebbene non vi sia un'esatta estrazione della pietra, esiste la tecnica 'a cantieri' con una malta forte come legante. La tipologia è diversificata: dal piccolo presidio all'edificio disposto su due livelli, talvolta turriti, a seconda dell'impegno produttivo e colturale. A differenza delle masserie tradizionali poste più a valle, già oggetto di una notevole storiografia, questi casi di architettura rurale posti più a monte non sono mai stati oggetto di indagine sistematica. Il contributo si propone di mettere a fuoco questo patrimonio quasi inedito e di illustrare una metodologia di conoscenza integrata legata alle peculiarità del sito vulcanico. La conservazione di queste architetture vernacolari, infatti, gioca un ruolo centrale nella lettura e comprensione dei valori multidimensionali del paesaggio culturale Vesuvio-Baia di Napoli. Il contributo si propone di mettere a fuoco questo patrimonio quasi inedito e di illustrare una metodologia di conoscenza integrata legata alle peculiarità del sito vulcanico. La conservazione di queste architetture vernacolari, infatti, gioca un ruolo centrale nella lettura e comprensione dei valori multidimensionali del paesaggio culturale Vesuvio-Baia di Napoli. Il contributo si propone di mettere a fuoco questo patrimonio quasi inedito e di illustrare una metodologia di conoscenza integrata legata alle peculiarità del sito vulcanico. La conservazione di queste architetture vernacolari, infatti, gioca un ruolo centrale nella lettura e comprensione dei valori multidimensionali del paesaggio culturale Vesuvio-Baia di Napoli.Marino, BG.; Ragosta, A. (2022). Close to the volcan. Knowledge, conservation and enhancement of a Vesuvian vernacular heritage. Editorial Universitat Politècnica de València. 1055-1062. https://doi.org/10.4995/HERITAGE2022.2022.153771055106

The LD Adolescent and the Sat

School personnel can help LD students prepare for the SAT in a variety of ways.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66543/2/10.1177_105345128502000402.pd