1,355,630 research outputs found
Assessing the stability of underground caves through iSUMM (innovative, straightforward, user-friendly, mechanically-based method)
No full textA huge number of sinkhole events has been recorded in different Italian urban areas, with an occurrence frequency largely increasing in the last decades, sometimes even causing loss of human lives. The main reason for such catastrophic events is the presence of man-made underground cavities, excavated within soft rocks, several decades ago and then abandoned, at shallow depths. Here, the possibility of interaction with overlying buildings and infrastructures and the corresponding sinkhole hazard is relatively high. In such contexts, the low mechanical properties of the soft rock formations where the cavities have been excavated, like those formed of calcarenites, which outcrop in large areas of Southern Italy, and their high susceptibility to weathering processes, represent one of the most important predisposing factors for instability. Therefore, assessing the stability of underground cavities is crucial for land management and planning purposes. The mechanically-based stability charts developed by Perrotti et al. (Int J Geomech 18(7):04018071, 2018) have proved to be a valid tool for preliminary stability assessment and, although allow to identify an eventual proneness of the cave to instability, they do not provide quantitative assessment about the safety margin itself. In that regard, this study intends to present the most recent outcomes obtained in the development of the methodology and is aimed at promoting an enhanced way for their application, so that the charts can become an operative tool for preliminary sinkhole hazard assessment in similar regions in the world
Developing mechanically-based charts to address the assessment of underground cave stability
No full textNatural or anthropogenic sinkholes threaten diffuse areas of the italian territory. A specific research project aimed at defining an overall methodology for susceptibility analysis and risk mitigation of underground cave sinkholes, from cave identification to modelling failure mechanisms and defining mitigation interventions, has been recently developed. Based on two levels at different scale of analysis, i.e. urban area and single cavity scale, the methodology at the first level is aimed at defining quantitative procedures to assess in a preliminary way the stability of underground caves at the urban area scale. As a matter of fact, when dealing with a large number of cavities, single-cavity scale investigations can be time- and cost-consuming, resulting in huge economical investments. Therefore, a preliminary approach to detect those caves that are characterized by relatively high failure susceptibility level is necessary to make choices for investing more sophisticated analyses. In particular, the project has furtherly developed a methodology already proposed by Perrotti et al. (2018, 2019) aimed at assessing the stability conditions of underground caves by using charts based on the results of parametric finite element analyses. The use of such stability charts is straightforward since they are based only on simple information regarding the cave geometry and the geo-mechanical parameters. An advanced version of the charts has been proposed in the aforementioned project, which
includes also the quantitative assessment of a safety factor range. The enhanced version of the stability charts has been also validated against field data.The methodology is not intended to replace proper site-specific stability analyses and models implementing the actual cave geometry and the rock mass stress-strain state and should be considered only for speditive preliminary stability assessment
A visão crítica da literatura infantil na década de 1980 em O texto sedutor na literatura infantil, de Edmir Perrotti
No full textApplying the analytical method proposed by Maria do Rosário Longo Mortatti, it is presented an study of the textual configuration of the book O texto sedutor na literature infantile ,from Edmir Perrotti, allowing to understand: a) author´s concepts about the children's literature; b) thematic contents and structural-formal textual options; c) the speech’s determination according to its relationship with the author's place in society, the historical moment; the needs and goals established to reach the reader. This study also presents Perrotti´s thoughts about several other Brazilian researchers of children's literatureUtilizando o método analítico proposto por Maria do Rosário Longo Mortatti, desenvolve-se análise da configuração textual da obra O texto sedutor na literatura infantil, de Edmir Perrotti. O método permite compreender:a) a visão do autor sobre a literatura infantil;b) as opções temático-conteudísticas e estruturais-formais do texto;c) a determinação do discurso em função das relações do autor com seu lugar social, momento histórico, necessidades e propósitos estabelecidos com o leitor,circulação e utilização esperadas.Apresenta-se, ainda, o pensamento de Perrotti sobre outros pesquisadores brasileiros da literatura infantil.  
Sinkhole susceptibility assessment of underground caves in soft rocks by means of FEM-based charts.
No full textThe presence of man-made underground caves in soft carbonate rocks susceptible to degradation processes due to weathering nowadays induce high risk conditions in the Apulia region (Southern Italy) which is characterised by a huge number of caves spread in the territory. In recent years, several collapses affected some of these cavity systems, involving structures and roads located at the ground surface and, therefore, inducing high risk for human life and properties. In order to comply with this problem at the regional scale, Perrotti et al., 2018, have proposed specific charts aimed at assessing at a preliminary stage the stability conditions of a cave along with a safety margin with respect to the occurrence of failure. The charts have been defined upon the results of a large set of parametric two-dimensional finite-element analyses of ideal cases of underground cavities that account for the typical geometrical features of the caves and the range of mechanical properties of these rocks. The relationships obtained in terms of plots representing the ratio between the strength mobilized at failure and the vertical stress at the cavity roof against the ratio between cave width and roof thickness identify mechanically-based threshold envelopes for stability. In this paper, applications of the stability charts to case studies of man-made underground caves of soft carbonate rocks, either subjected to failure in the past or still stable, are discussed. In the first case the applications proposed show the role of specific structural elements, as pillars and walls, on the general stability of the examined quarry system, while in the second case an indication on the safety factor of the cave with respect to instability has been derived. Therefore, the proposed stability charts have been verified to provide a reliable method to assess in a preliminary way the stability of underground cavities in soft carbonate rocks, so that, for those situations where the safety margin results to be low, more detailed and sophisticated numerical models need to be developed
Agro-energy production as a driving force in the socio-ecological transition of rural environments: a significant case study within the Alta Murgia National Park.
No full textPapers on Territorial Intelligence and Sustainable economics within the new culture of development, ENTI, Liège.This paper explores the possibility of considering the productive environment of a South-European rural region, the Alta Murgia National Park in the Italian region of Apulia, as the socio-economic framework for a new culture of territorial development, ingenerated by the local diffusion of dedicated biomass crops. We intend to draw particular attention to the processes involved in the implementation of the green energy and energy efficiency policies, at the territorial and regional levels, and their material and immaterial (social perception) impacts on the local rural landscape.Cette étude se propose d'analyser le contexte socio-économique du territoire rural du Parc National de l'Alta Murgia, au sein de la région italienne de Pouilles, à l'aune des changements induits par la diffusion des cultures dédiées à la production de biomasses et biocarburants et de la conséquente expérimentation d'une nouvelle culture du développement territorial. Cette hypothèse sera explorée à partir d'une réflexion sur l'application des principes de durabilité et d'efficience énergétique au sein des cycles productifs propres aux entreprises agricoles et zootechniques locales, ainsi que sur leur retombées physiques et liées aux représentations sociales du paysage rural
Conceiving the (everyday) landscape of energy as a transcalar infrastructural device. The progressive construction of a working hypothesis
No full textQuesto contributo persegue due obiettivi principali. In primo luogo, l'articolo introduce ed esplora un’ipotesi fondamentale fondata sulla possibilità di leggere i “paesaggi dell’energia” - intesi nella loro dimensione di “paesaggi del quotidiano” - in termini di “dispositivi infrastrutturali”. Alla luce della loro connotazione transcalare, tali dispositivi appaiono atti a supportare la sperimentazione collettiva di differenti modalità d’interazione fra attori eterogenei, attraverso scale politiche e geografiche complementari. In secondo luogo, la riflessione elaborata a partire dall’esplorazione di tale ipotesi fondamentale si confronta con il dibattito scientifico sviluppato negli Stati Uniti a partire dalla pubblicazione nel febbraio 2010 del secondo volume della rivista New Geographies dell’Harvard University Graduate School of Design, volume intitolato “Landscapes of Energy” (a cura dall’architetta e geografa Rania Ghosn). Questa pubblicazione delinea uno stato dell’arte delle diverse declinazioni contemporanee della “geografia dell’energia”. Al centro di tale riflessione si collocano lo studio dei processi di spazializzazione dei sistemi reticolari di produzione e distribuzione energetica e l’analisi dell’impatto materiale e immateriale (geografico e sociale) di tali reti sui paesaggi attraversati.
ENGLISH ABSTRACT
This paper's goals are twofold. It introduces and explores, through a step-by-step demonstration process, a fundamental hypothesis, concerning the possibility of reading the everyday landscape of energy as an infrastructural device. This device is able to support different ways, for social actors, researchers and professionals, of experimenting with new forms of interaction between geographic and socio-political scales. Complementarily, the article proposes the contextualization of this hypothesis within the debate which originated after the publication in February 2010 of the second issue «Landscapes of Energy» of the Harvard GSD journal New Geographies (editor-in-chief: arch. Rania Ghosn). Introducing the scientific hypothesis of «thinking energy spatially», and discussing the provocative statement «energy is a spatial product», the various articles collected in this journal propose different approaches to the historicization of «the dialectical relation between energy and society.
Stability charts based on the finite element method for underground cavities in soft carbonate rocks: validation through case-study applications
No full textThe stability of man-made underground cavities in soft rocks interacting with overlying structures and infrastructures represents a challenging problem to be faced. Based upon the results of a large number of parametric twodimensional (2-D) finite-element analyses of ideal cases of underground cavities, Accounting for the variability both cave geometrical features and rock mechanical properties, specific charts have been recently proposed in the literature to assess at a preliminary stage the stability of the cavities. The purpose of the present paper is to validate the efficacy of the stability charts through the application to several case studies of underground cavities, considering both quarries collapsed in the past and quarries still stable. The stability graphs proposed by Perrotti et al. (2018) can be useful to evaluate, in a preliminary way, a safety margin for cavities that have not reached failure and to detect indications of predisposition to local or general instability phenomena. Alternatively, for sinkholes that already occurred, the graphs may be useful in identifying the conditions that led to the collapse, highlighting the importance of some structural elements (as pillars and internal walls) on the overall stability of the quarry system
SYNTHESIS OF BENZOFURANONES VIA MALONATES DESYMMETRIZATION
No full textSYNTHESIS OF BENZOFURANONES VIA MALONATES DESYMMETRIZATION.
S. Placidi,a A. Puglisi,a C. Giustini,a A. Ricucci,a E. Perrotti,a L. Massaro,a D. Morra,a F. Ciucci,a A. Zucchet,a A. Antenucci,a M. Moliterno,a R. Salvio,a,b M. Bellaa
aDepartment of Chemistry, “Sapienza” University of Roma, P.le Aldo Moro 5, 00185 Roma; bIMC-CNR, Sezione Meccanismi di Reazione, P.le Aldo Moro 5, 00185 Roma; e-mail: [email protected]
Benzofuranones are interesting molecules due to their biological activity.1 Up today few studies have been conducted with respect to their synthesis compared to the corresponding oxindoles. The enantioselective synthesis of these compounds is currently carried out starting from pre-assembled benzofuranone moiety.2 In this work we present the synthesis of chiral, non-racemic benzofuranones, based on an asymetric intramolecular desymmetrization, catalyzed by Cinchona alkaloids and derivates, like quinine and catalyst I.3 Benzofuranones 4 are achieved by the addiction of malonates 1 to quinones 2 to give arylated achiral malonates 3 that subsequently undergo a cyclization reaction (Scheme1). Desymmetrization is an efficient metod for the synthesis of enantioenriched compounds starting from prochiral molecules.4 This approach allows to obtain products with high yields, up to 95%, and enantiomeric ratios as high as 97.5:2.5, in the best cases.
Scheme 1. Synthesis of benzofuranones organocatalyzed by Cinchona alkaloids and proposed transition state leading to the major enantiomer (R).
References
1. For examples see: a) K. M. Dawood, Expert Opin. Ther. Patents 2013, 23, 1133; b) C. Charrier, J. Clarhaut, J.-P. Gesson, G. Estiu, O. Wiest, J. Roche, P. Bertrand, J. Med. Chem. 2009, 52, 3112. 2. Y. Li, X. Li, J.-P. Cheng, Adv. Synth. Catal. 2014, 356, 1172.
3. A. Puglisi, C. Giustini, A. Ricucci, E. Perrotti, L. Massaro, D. Morra, F. Ciucci, A. Zucchet, A. Antenucci, M. Moliterno, S. Placidi, F. Sciubba, L. Galantini, R. Salvio, M. Bella, Chem. Eur. J. 2018, 24, 6945.
4. X. P. Zeng, Z. Y. Cao, Y. H. Wang, F. Zhou, J. Zhou, Chem. Rev. 2016, 116, 7330
Maxillary sinus augmentation with a porous synthetic hydroxyapatite and bovine-derived hydroxyapatite: a comparative clinical and histologic study.
No full textThe aim of this study was to determine the clinical and histologic results of a porous synthetic hydroxyapatite (HA) compared with bovine-derived HA used in maxillary sinus augmentation.A total of 100 titanium implants were placed in 40 patients. Patients in need of maxillary sinus augmentation were divided into 2 groups. Group 1 received bovine-derived HA (20 patients with 50 implants), while group 2 received a porous synthetic HA (20 patients with 50 implants). After a healing period of 6 months, second-stage surgery was carried out. In 50 cases (25 from group 1 and 25 from group 2), bone cores were harvested from grafted areas and processed for histologic examination.Four implants that failed to osseointegrate were removed at the second-stage surgery (2 from a patient from group 1, and 2 from a patient from group 2). All patients were followed for at least 1 year after loading. Histologically, most of the HA particles from both groups were surrounded by newly formed bone. No statistically significant differences were found with respect to percentage of newly formed bone between the 2 groups (P = .031); however, the groups did differ significantly with respect to the percentage of residual graft material observed (P = .001).This study demonstrates that both bovine-derived and porous synthetic HA can be used successfully as graft materials for maxillary sinus augmentation. The clinical performance of the 2 materials was similar. (Clinical Trial
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