1,721,255 research outputs found
La cultura maker per l’innovazione digitale
Full text linkL’articolo traccia una visione del futuro delle tecnologie digitali poste di fronte ad una sfida di sviluppo e innovazione, quella di fondere il mondo dell’immateriale proprio della produzione digitale, con la materia fisica, integrando da un lato intelligenza e capacità computazionali negli oggetti di uso quotidiano, dall’altro utilizzando tecnologie digitali per la fabbricazione stessa di artefatti. Questa visione è promossa dal movimento Fab Lab, la rete mondiale di intelligenze e tecnologie che ha incarnato la cosiddetta terza rivoluzione digitale, quella della fabbricazione digitale. In ciò che segue ripercorreremo i momenti salienti della storia del movimento, nato al Center for Bits and Atoms del MIT, e fotograferemo la realtà italiana, con particolare riferimento al Fab Lab del Santa Chiara Fab Lab, il centro per l’innovazione interdisciplinare dell'Università di Siena. Questo laboratorio è una moderna bottega di design a servizio della ricerca, della formazione e della terza missione, dove la fabbricazione digitale si innesta su progetti che affrontano in modo fortemente interdisciplinare i temi dell'inclusione sociale, dell'accessibilità, della salute, dell’innovazione nei beni culturali e della sostenibilità.The article provides a vision of the future of digital technologies which address an
innovation challenge to merge the immaterial world of the digital production with the
physical world, by integrating intelligence and computational capacity into everyday
objects, as well as by using digital technologies to produce such artefacts. This vision is
promoted by the Fab Lab movement, the international network of intelligences and
technologies which embodies the so-called third digital revolution, namely the digital
fabrication revolution. In what follows, we retrace the highlights of the movement’s
history, that was born at the MIT’s Center for Bits and Atoms, and then we focus on the
Italian context with references to the Santa Chiara Fab Lab, the centre for
interdisciplinary innovation of the University of Siena. This lab is a modern design
workshop that supports academic research, training and third mission. The digital
fabrication is fully integrated in these activities to address the challenges of social
inclusion, accessibility, health, cultural heritage and sustainability
Is deafness a disability?: Designing hearing AIDS beyond functionality
No full textThe question whether deafness is a disability causes controversial and emotionally charged debates. The experience of hearing loss is different from the experience of being born deaf, as well as the need and willingness of using hearing aids. Following a medical model of disability, deafness has been traditionally viewed as a physical impairment. This paper points out highly debated issues related to the design of assistive technologies for people with hearing impairment. It illustrates the design case of a suite of smart jewels designed to address their emotional and socio-cultural needs beyond the functional goal of supporting hearing. The design case calls for a shift in the attitude toward disability - from a medical model which sees impairment as a personal deficiency to be "normalized", to a socio-cultural model which views disability as a socially constructed concept defined by the obstacles of a hearing-oriented world
Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains
No full textIn concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical model allows an easy and reliable reinforcement evaluation, in agreement with a more refined 3D analysis but with a reduced computational burden
Enriching the food experience: A design journey through innovative technologies for creating, experimenting, consuming, socializing, and playing with food
No full textWhen we were invited to write a chapter on food and technology for
this book, we thought that the enterprise would have deserved an entire
book. Digital technologies are pervading the dining table, the kitchen,
and any digital or physical space where we can grow, create, share, enjoy,
consume, learn about, recycle, store, and distribute food.
This chapter is by necessity a personal journey on the theme, which
touches upon how digital technologies feature the food experience in
diverse faces and directions combining emerging approaches.
To help reflecting on the food experience enabled by digital technologies,
we draw a fil rouge around the way digital technologies are likely to
change our experience of food. Our fil rouge unravels around five themes
that represent stopovers along a narrative and experience-centered journey
focused on creating, experimenting, consuming, socializing, and playing
with food.
Our review does not claim to be exhaustive or complete. Rather, it aims
at devising some “food for thought” and stimulating a sensitivity toward
potential evolutions and transformations induced by digital technologies
in the food realm
A mixed approach for determination of initial cable forces in cable-stayed bridges and the parameters variability
No full textThe determination of initial cable forces in cable-stayed bridges is an important first step in design and analysis of the structure under external loads. Adjustments of stay forces are often required during construction in order to assure the requested behaviour of the bridge in terms of final geometrical configuration and internal force distribution. An accurate assessment of the stay tensioning system allows designers to obtain a good result at the end of construction, by considering the parameters involved as deterministic quantities, assuring the observance of the execution tolerances during works. Actual loads and their variations need instead a stochastic approach which can give useful indications about the effects of parameter variations. Particularly, the measurement on site of the actual values of stay elongations contains errors and the actual values of pre-stressing forces and working site loads are subjected to unknown variations. In this paper a procedure is implemented which takes into account the stochastic variation of stay elongations and the related uncertainties. The presented method does not require large computational efforts or computer memory. By approximating the probability density distribution of the variables involved by the Gaussian curve, a closed form expression of the imposed elongations given to stays and their variations during erection is provided. The main aim is to obtain an accurate prediction of the differences between the deterministic quantities found by the design analyses and the actual values of deck deformations and stresses in the erection of steel cable-stayed bridges
Serviceability and Ultimate Safety Checks of Segmental Concrete Bridges through N-M and M-V Interaction Domains
No full textIn current engineering practice, safety checks on serviceability and determinations of ultimate limit states of segmental bridges built by cantilevering are generally performed, either considering separately the contributions of axial force N, bending moment M, and shear force V, or considering the interaction effects through approximate expressions supplied by building codes. During construction stages and service life, the interaction between internal forces can be of fundamental importance in establishing the actual degree of structural safety and, for this reason, a different philosophy for performing checks in segmental bridges is proposed in this paper, plotting N-M and M-V interaction domains for cracking, construction stages, and serviceability (elastic domains) as well as M-V interaction domains for ultimate limit states (failure domains). Delayed deformations as a result of creep are considered, as are bonded and unbonded prestressing. A model is developed for plotting bending-shear domains at the ultimate limit state, underlining the strength reduction that occurs in concrete sections with external prestressing versus beams with full internal prestressing. A numerical application on an actual segmental bridge built by cantilevering was performed to show the proposed methodology, based entirely on strength domains, for safety checks. The load and stress paths in the construction stages are highlighted by considering the effects of creep in concrete, whereas bending-shear interaction is evaluated in the two cases of fully bonded prestressing and partially unbonded prestressing. The results show that safety checks which are performed based on approximate assumptions and expressions that do not explicitly consider the interaction effects can lead to unsafe evaluations, and it also shows that the proposed methodology allows engineers to take into account simultaneously any aspect related to cross-sectional strength on serviceability and ultimate limit states
SIMPLE PLASTIC MODEL FOR SHEAR CRITICAL SFRC BEAMS
No full textA simple physical model, for prediction of ultimate shear strength of steel fiber reinforced
concrete (SFRC) beams is developed on the basis of a plastic approach originally proposed for
reinforced concrete (RC) beams without stirrups. It is founded on the hypothesis that cracks can be
transformed into yield lines, and thus is know as Crack Sliding Model (CSM). First, the CSM is improved
in order to take into account the shear strength increase for deep beams, due to the arch effect. Then,
the effectiveness factors for fibrous concrete under biaxial stresses are evaluated, taking into account
the post-cracking tensile strength of SFRC and its ability to control slippage along shear cracks. With
the aim of providing a handy and fast tool for design of SFRC beams without stirrups, a simplified
design model is also derived. Finally, the proposed models are validated by the results of a large set of
experimental tests taken from literature
A model for SFRC beams without shear reinforcement
No full textIn this paper a physical model, for the prediction of ultimate shear strength of Steel Fibers Reinforced Concrete (SFRC) beams is developed from the plastic Crack Sliding Model (CSM) introduced by Zhang (1997), based on the hypothesis that cracks can be transformed into yield lines. In this work the effectiveness factors are recalculated for SFRC beams and some further developments are introduced in the CSM, taking into account the fundamental post cracking tensile strength contribute of SFRC. The proposed model is validate by a large set of tests collected in literature and some numerical analyses were carried out to show the influence of fibers on the failure beams mode
Experimental test results vs. analytical prediction of welded joint strength in hybrid steel trussed concrete beams (HSTCBs)
No full textThe aim of the paper is to provide practical guidelines for the design of welded
joints of steel truss for encased composite steel–concrete beams. The results of
experimental tests are presented and interpreted. The steel truss is made of a steel
plate acting as the bottom chord, made of S355 structural steel, coupled with steel
rebars which form the upper chord, and steel inclined web rebars (V-reverse) welded
to the two chord elements, both of them made of steel B450C. Butt welded joints of
web bar to bottom steel plate and fillet welding joints of inclined web bars to top
chord bars were tested, as they are different from the ones which are normally used
due to the coupling of different steel types and complex geometry. For the prediction
of strength of fillet welding joints, two analytical expressions are derived: the first is
based on a local failure criterion and the second on a limit domain of the welding
section. Comparison with experimental data proves the equivalence and reliability
of the proposed indications. Guidelines for choosing the effective dimensions of
the fillet weld able to ensure a required strength are provided. For validation of the
suggested guidelines, a high precision digital scanner is used to determine the
geometrical characteristics of the fillet weld
Experimental in situ behaviour of unreinforced masonry elements retrofitted by pre-tensioned stainless steel ribbons
No full textThe results of in situ tests carried out on unreinforced and reinforced poor rubble masonry full-scale walls in the earthquake prone Messina (Italy) area are presented and discussed. This experimental research was aimed at the assessment of the in plane shear behaviour of ancient masonry strengthened with an innovative system for masonry and retrofitting of reinforced concrete element constituted by three-dimensional pre-tensioned stainless steel ribbons. A comparison between different strengthening configurations was made in order to characterise the behaviour of masonry panels under shear-compression load, focusing attention on the diagonal cracking failure mode. The effectiveness of retrofitting method in enhancing strength and ductility of poor rubble masonry walls is proved by comparison of the response of the unreinforced and reinforced structural systems
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