633 research outputs found
Deformation mechanisms and geometries of superposed fault zones in dolostones
No full textUnderstanding how heterogeneous rock volumes deform is crucial in structural geology, and several studies have addressed this issue by focusing on the impact that the mechanical stratigraphy of a layered stratigraphic sequence has on deformation. However, mechanical layering can also develop subparallel to fault surfaces within the upper crust, and how these anisotropies affect subsequent deformation has been much less explored. This work addresses this aspect by structurally and mechanically characterizing superposed fault zones developed in Triassic dolostones that crop out in the fold-and-thrust belt of the southern Apennines. We investigate how layering associated with an early, reservoir-scale, normal fault zone (F1), inherited from Upper Triassic−Lower Jurassic pre-orogenic extension, influenced the deformation mechanisms and the geometry of younger strike-slip faults (F2) that formed at an angle to it in the early Pliocene in association with out-of-sequence tectonics during the Apennine orogeny. We combined field surveys and laboratory analyses using a multiscalar and multimethodological approach. Meso- and microstructural observations and geomechanical, laboratory, and in situ tests were employed to describe fault rock attributes. We found that the architecture of the F1 normal fault primarily consists of four tens-of-meters-thick, subparallel fault rock units. They have a cataclastic core, and are bounded in the hanging wall by cemented micromosaic breccia, and in the footwall by high-strain and low-strain fault rocks. The younger F2 strike-slip faults developed alternatively as either cataclastic shear bands or compaction bands and occur in either localized or anastomosing geometries. By combining data, we demonstrate that the particle size distribution, porosity, and rock strength of the fault rock units related to older normal faults are the main controls on the deformation mechanisms (i.e., cataclasis versus compaction) and geometry (i.e., localized anastomosed) of the subsequent strike-slip faults. Our study highlights that preexisting highly porous fault rocks favor the development of compaction deformation bands. Conversely, low rock strength facilitates the formation of discrete and diffuse slip surfaces. These results can have significant implications for assessing fluid flow in multifaulted dolomite reservoirs
Homogenisation of elastic properties of foamed cemented soils based on x-ray microtomography investigations
No full textIn the present work, semi-analitycal Mean-Field Eshelby-based Homogenisation approaches are used to determine the elastic relevant mechanical parameters of Lightweight Cemented Soils (LWCS), i.e., heterogeneous materials characterised by a double porosity microstructure consisting of foam-induced large voids immersed in a cemented small-porous matrix. Homogenisation approach, never employed in the field of treated soils and applied for the first time to LWCS, allows taking into account the microstructural features of the material and their evolution over curing time. This procedure requires several input parameters, i.e., the artificial foam-induced porosity, the bulk and shear moduli and the Poisson ratio of the phases forming LWCS samples (i.e. cemented soil matrix, portlandite crystals). The evolution of foam-induced porosity over time is inferred from x-ray microtomography scans performed on a LWCS sample at different curing times, i.e., 7, 28 and 60 days, whereas the mechanical parameters are derived from experimental tests, performed on cemented samples with or without foam addition. The homogenised stiffness moduli, computed for different curing times, show a good agreement with the available experimental results, confirming the feasibility of the semi-analytical homogenisation model. The use of x-ray computed microtomography coupled with the proposed homogenisation method, can efficiently predict the elastic parameters of LWCS and their evolution over time, taking into account the role played by the microstructure
Nathan Filer and Agata Vitale
No full textWhat can writers and teachers of Creative Writing learn from psychiatry, neuroscience, and other medical disciplines about the links between creativity and mental illness?
Nathan Filer, author of 'The Shock of the Fall', and Agata Vitale, Senior Lecturer in Abnormal/Clinical Psychology at Bath Spa University, will be in conversation with Richard Hamblyn of Birkbeck College
Il giudizio etico sui comportamenti imprenditoriali: verso una modellizzazione secondo l’Approccio Sistemico Vitale (ASV)
No full textBARILE S., GATTI M., PROIETTI L., Il giudizio etico sui comportamenti imprenditoriali: verso una modellizzazione secondo l’Approccio Sistemico Vitale (ASV), in Sergio Barile (a cura di), L’impresa come sistema. Contributi sull'Approccio Sistemico Vitale (ASV), Giappichelli, Torino, 2006
Capitolo senza attribuzioni ai singoli AutoriBARREL S., CATS M., L. Proietti, Ethical judgment on entrepreneurial behavior: towards a modeling according to the Systemic Approach Vitale (ASV), in Sergio Barile (ed.), The firm as a system. Contributions on the approach Systemic Vitale (ASV), Giappichelli, Turin, 2006 Chapter without attribution to individual author
Multiscale Analysis on the Behaviour of a Lime Treated Bentonite
Get PDFAbstractAn insight into the microstructural evolution of clay-lime-water systems and its influence on the hydro-mechanical behaviour of treated bentonite has been presented. The time-dependent mineralogical and microstructural changes induced by lime addition on a natural bentonite have been investigated in order to provide a better understanding of the kinetic of the ongoing reactions. The effects of lime addition on the clay particle arrangements have been inferred from dynamic light scattering measurements, whereas the mineralogical changes have been monitored at increasing curing time by X-Ray diffraction and thermogravimetric analysis. The bentonite showed a high initial reactivity characterized by a rapid and total consumption of lime, which promoted the formation of new hydrated phases since the very short term (0 days of curing). Oedometer tests on not treated and lime stabilised saturated samples have been performed at increasing curing times. The results showed the combined effect of clay particles arrangement and bonding on the mechanical behaviour of treated samples
Il giudizio etico sui comportamenti imprenditoriali: verso una modellizzazione secondo l’Approccio Sistemico Vitale (ASV)
No full textATTENZIONE: edizione riveduta ed aggiornata
BARILE S., GATTI M., PROIETTI L., Il giudizio etico sui comportamenti imprenditoriali: verso una modellizzazione secondo l’Approccio Sistemico Vitale (ASV), in Sergio Barile (a cura di), L’impresa come sistema. Contributi sull'Approccio Sistemico Vitale (ASV), Giappichelli, Torino, 2006
Capitolo CON attribuzioni ai singoli AutoriWARNING: revised and updated edition BARREL S., CATS M., L. Proietti, Ethical judgment on entrepreneurial behavior: towards a modeling according to the Systemic Approach Vitale (ASV), in Sergio Barile (ed.), The enterprise as a system. Contributions on the approach Systemic Vitale (ASV), Giappichelli, Turin, 2006 Chapter WITH allocations to individual Author
Mechanical Behaviour of Soil Improved by Alkali Activated Binders
Get PDFThe use of alkali activated binders to improve engineering properties of clayey soils is a
novel solution, and an alternative to the widely diffused improvement based on the use of traditional
binders such as lime and cement. In the paper the alkaline activation of two fly ashes, by-products
of coal combustion thermoelectric power plants, has been presented. These alkali activated binders
have been mixed with a clayey soil for evaluating the improvement of its mechanical behaviour.
One-dimensional compression tests on raw and treated samples have been performed with reference
to the effects induced by type of binder, binder contents and curing time. The experimental evidences
at volume scale of the treated samples have been directly linked to the chemo-physical evolution
of the binders, investigated over curing time by means of X Ray Diffraction. Test results showed
a high reactivity of the alkali activated binders promoting the formation of new mineralogical
phases responsible for the mechanical improvement of treated soil. The efficiency of alkali activated
binders soil treatment has been highlighted by comparison with mechanical performance induced by
Portland cement
Analyse waterrobuuste inrichting: Voor nieuwbouw en vitale & kwetsbare functies
No full textDeze rapportage is het resultaat van een verkenning met deskundigen uit de vitale sectoren (o.a. elektriciteitsvoorziening, drinkwatervoorziening, etc.). Het rapport biedt inzicht in de mogelijke ruimtelijke maatregelen voor een optimale waterrobuuste inrichting van vitale en kwetsbare functies in relatie tot de bescherming tegen een overstroming. Doel is om via een drietal ontwerpschetsen van waterrobuuste inrichting en een tabel van mogelijke maatregelen een inspirerend handelingsperspectief te bieden aan verschillende doelgroepen die te maken hebben met investeringen in nieuwbouw van vitale en kwetsbare functies. Uit de verkenning is gebleken dat waterrobuust ontwerpen en inrichten altijd om gebiedsgericht maatwerk vraagt. Hierbij bepalen verschillende gebiedskenmerken en afwegingscriteria welk maatregelenpakket voor dat gebied het meest (kosten)effectief is. In een integraal ingerichte waterrobuuste wijk is functioneren mogelijk tot het overstromingsniveau waarop het is ontworpen.Deltaprogramm
Co-authorship networks and scientific performance. Evidences from a case study by using different bibliographic archives
No full textThe present contribution aims at exploring the effects of collaborative behaviours on scholar scientific performance. Mainly thanks to the availability of international bibliographic archives, seminal studies in various fields have been focused on co-authorship networks as a proxy of scholars' collaborative skills. To this purpose, several data sources are available but they present some drawbacks, especially when a specific discipline or community is under analysis. For instance, international archives might not be able to cover all kinds of scientific production, especially for social sciences where papers can be published in books or in national-oriented journals.
In this scenario, we gathered co-authorship data on the scientific community of Italian academic statisticians as recorded in the Italian Ministry of University and Research database at March 2010. We used three bibliographic archives covering top-international journals as well as thematic and nationally oriented publications: Web of Science (WoS), Current Index to Statistics (CIS), and bibliographic information related to nationally funded research projects (PRIN). Since each data source showed peculiar characteristics influencing both network properties and performance results, we also discussed the main issues and the practical implications on merging data sources (i.e., record linkage and author name disambiguation) improving the bibliographic data quality for reconstruct an unified co-authorship network.
Both network and individual covariates are used to model individual h-index by Generalized Extreme Value (GEV) distribution. Our results provided evidence of our hypotheses on distinct collaboration patterns among statisticians, as well as distinct effects of scientist network positions on scientific performance, by both Statistics subfield and data source.
References
De Stefano, D., Zaccarin, S. (2016). Co-authorship networks and scientific performance: an empirical analysis using the generalized extreme value distribution. Journal of Applied Statistics 43: 262-279.
De Stefano, D., Fuccella, V., Vitale, M. P., Zaccarin, S. (2013) The use of different data sources in the analysis of co-authorship networks and scientific performance. Social Networks 35: 370–381.
Fuccella, V., De Stefano, D., Vitale, M. P., Zaccarin, S. Improving co-authorship network structures by combining multiple data sources: evidence from Italian academic statisticians. Scientometrics (to appear
- …
