Search results for "Crete"
showing 10 items of 2495 documents
A fractional-order model for aging materials: An application to concrete
2018
Abstract In this paper, the hereditariness of aging materials is modeled within the framework of fractional calculus of variable order. A relevant application is made for the long-term behavior of concrete, for which the creep function is evaluated with the aid of Model B3. The corresponding relaxation function is derived through the Volterra iterated kernels and a comparison with the numerically-obtained relaxation function of Model B3 is also reported. The proposed fractional hereditary aging model (FHAM) for concretes leads to a relaxation function that fully agrees with the well-established Model B3. Furthermore, the FHAM takes full advantage of the formalism of fractional-order calculu…
Behavior in compression of concrete cylinders externally wrapped with basalt fibers
2015
Abstract This paper gives additional information on the use of new class of composites constituted by Basalt Fiber Reinforced Polymer (BFRP) bonded with epoxy resin to concrete specimens as an alternative confinement material for compressed concrete members with respect to carbon or glass fibers. From the experimental point of view, concrete cylinders are wrapped with continuous fibers, in the form of sheets, applying both full and partial discrete wrapping with BFRP straps, and then tested in compression. For comparison, few other concrete cylinders are wrapped with Carbon Fiber Reinforced Polymer (CFRP) sheets and tested in compression. The number and type of plies (full or partial wrappi…
Tecnica e poetica. Il calcestruzzo armato nell'opera di Giuseppe Samonà
2021
Elemento distintivo e imprescindibile dell’opera di Giuseppe Samonà è l’utilizzo del calcestruzzo armato, come forma tecnica ma anche poetica, alla base del carattere estetico-figurativo delle sue architetture. Il differente utilizzo del calcestruzzo - spesso in forma monolitica, ricercando la continuità materica e spaziale tra interno ed esterno - deriva dal rapporto tipologia-morfologia: al prevalere dell’uno cambia il modo in cui il materiale viene impiegato e pertanto anche il linguaggio che ne deriva secondo un rapporto causa-effetto.
Percolation on correlated random networks
2011
We consider a class of random, weighted networks, obtained through a redefinition of patterns in an Hopfield-like model and, by performing percolation processes, we get information about topology and resilience properties of the networks themselves. Given the weighted nature of the graphs, different kinds of bond percolation can be studied: stochastic (deleting links randomly) and deterministic (deleting links based on rank weights), each mimicking a different physical process. The evolution of the network is accordingly different, as evidenced by the behavior of the largest component size and of the distribution of cluster sizes. In particular, we can derive that weak ties are crucial in o…
Organization and evolution of synthetic idiotypic networks
2012
We introduce a class of weighted graphs whose properties are meant to mimic the topological features of idiotypic networks, namely the interaction networks involving the B-core of the immune system. Each node is endowed with a bit-string representing the idiotypic specificity of the corresponding B cell and a proper distance between any couple of bit-strings provides the coupling strength between the two nodes. We show that a biased distribution of the entries in bit-strings can yield fringes in the (weighted) degree distribution, small-worlds features, and scaling laws, in agreement with experimental findings. We also investigate the role of ageing, thought of as a progressive increase in …
Discrete-Time Adaptive Hysteresis Filter for Parallel Computing and Recursive Identification of Preisach Model
2018
High-precision motion control systems, for instance deployed for micro- and nano-positioning, often use the smart-material based actuators such as piezoelectric and magnetostrictive stages. Those exhibit inherent hysteresis nonlinearities which are challenging to compensate without precise hysteresis modeling. Even if a suitable hysteresis modeling approach is available, its parameter identification, correspondingly adaptation, at normal operating conditions constitute an essential task for the overall control design. This paper uses the direct recursive identification method for the Preisach hysteresis model and describes the fast parallel-computing discrete-time algorithm for an adaptive …
From Lattice Valued Theories to Lattice Valued Analysis
2015
We claim and justify that the future of a fuzzy logic is in the interconnection of various well-developed theories. We are focused on a lattice valued analysis that unifies the treatments of atomic elements, sets of atomic elements, functions between sets of atomic elements and their properties. We clarify the relationship between a fuzzy function and its ordinary core. We discuss the property of continuity of a fuzzy function in a lattice valued topology.
Two-LO-Phonon Resonant Raman Scattering in II-VI Semiconductors
1996
Recently, absolute values of socond-order Raman scattering efficiency have been measured around the E 0 and E 0 + Δ 0 critical points of several II-VI semiconductor compounds. The measurements were perfomed in the z(x,x)z backscattering configuration on (001) (ZnSe and ZnTe) and (110) (CdTe) surfaces. They show strong incoming and outgoing resonances around the baud gap and larger scattering efficiencies as compaered to III-V compounds. A theoretical model which includes excitons as intermediate states in the Raman process is shown to give a very good quantitative agreement between theory and experiment. Only a small discrepancy exists, while III-V compounds the discrepancies were close to …
Compressive response of substandard steel-jacketed RC columns strengthened under sustained service loads: From the local to the global behavior
2018
Abstract This paper presents an experimental investigation on substandard partially steel jacketed RC columns strengthened under sustained loads and loaded until failure. The aim of the study is to compare the compressive response of preloaded columns with respect to the tests without preload to obtain a more realistic prediction of load-carrying capacity of structural columns after retrofitting under serviceability loads. The influence of the preload level, the delayed contribution of the confining device during the loading process and the time dependent effects are highlighted for the tested specimens. Based on the experimental observations, an analysis-oriented model is proposed for the …
2-Groups with few rational conjugacy classes
2011
Abstract In this paper we prove the following conjecture of G. Navarro: if G is a finite 2-group with exactly 5 rational conjugacy classes, then G is dihedral, semidihedral or generalized quaternion. We also characterize the 2-groups with 4 rational classes.