197,037 research outputs found
Dendrimers as Multielectron Storage Devices
No full textDendrimers are complex, repeatedly branched tree-like compounds that can be synthesized with well-defined composition and a high degree of order.
Incorporation of redox-active units in a dendritic architecture enable us to gain information on: (i) dendrimer structure and superstructure; (ii) self-assembly processes; (iii) degree of electronic interaction and communication between redox units located in different sites; (iv) changes in conformation brought about by electron transfer processes. Electroactive dendrimers are attracting increasing interest in view of their possible application as sensors, catalysts, enzyme mimics, in which a redox centre is buried inside the dendritic nanoenvironment, and, last but not least, multielectron storage devices
Malattie dell'orecchio
No full textPatologia malformativa dell'orecchio esterno e medio. Patologia acquisita dell'orecchio esterno. Processi infiammatori dell'orecchio medio. Otite media cronica colesteatomatosa. Tumori dell'orecchio medio e della mastoide. Traumi dell'orecchio medio e dell'osso temporale. Otosclerosi. Patologia dell'orecchio interno
Electrochemistry of Functional Supramolecular Systems
No full textIncorporation of redox-active units in a dendritic architecture enable us to gain information on: (i) dendrimer structure and superstructure; (ii) self-assembly processes; (iii) degree of electronic interaction and communication between redox units located in different sites; (iv) changes in conformation brought about by electron transfer processes. Electroactive dendrimers are attracting increasing interest in view of their possible application as sensors, catalysts, enzyme mimics, in which a redox centre is buried inside the dendritic nanoenvironment, and, last but not least, multielectron storage devices
New Ground-Breaking Strategies in Bone Regeneration—In Memory of Nerio Ceroni
No full textThis editorial article is dedicated to the memory of the Nerio Ceroni, the grandfather
of the first author. Nerio Ceroni suffered from bone metastases and passed away in
January 2022
Cracking Behaviour of RC Beams Externally Strengthened with Emerging Materials
No full textThis paper presents some experimental results about cracking phenomena of reinforced concrete beams externally strengthened with
bonded composite materials. Carbon Fibre Reinforced Polymers (CFRP) laminates or steel (SRP) tapes have been used. Comparisons
with analytical results in terms of cracks width and crack spacing are reported using an analytical model developed by the authors, taking
into account the non-linear behaviour of materials and bond laws. Comparisons at service condition with code formulas are also
reported
Evaluation of bond strength in concrete elements externally reinforced with CFRP sheets and anchoring devices
No full textUse of anchoring devices can be useful to avoid or delay end debonding failure in reinforced concrete elements externally
bonded with fiber-reinforced plastic materials. Many theoretical formulations are now available to predict bond strength, but no design
provisions have been suggested to take into account the beneficial effect of anchorage devices. This paper presents the results of
experimental bond tests performed on concrete blocks externally strengthened with carbon fiber sheets. The prime focus is the evaluation
of effect given by three different types of anchorage systems upon increasing debonding load. A simple model is introduced to predict the
influence of the examined anchorage systems on the debonding load. Its accuracy is confirmed by comparisons with the experimental
results
STATISTICAL ANALYSIS OF DEBONDING LOAD IN CONCRETE ELEMENTS EXTERNALLY STRENGTHENED WITH CFRP MATERIALS
No full textAn overview of the main items about bond tests for concrete elements
externally strengthened with Carbon Fiber Reinforced Plastic (CFRP) materials is
presented. Firstly, the effect of set-up on results of bond tests is analysed; then the
experimental results of a wide database of bond tests collected by the Authors are
compared with some literature provisions in order to point out the reliability of the
examined strength models and evidence the role of the set-up. Furthermore, a general
procedure for developing design strength models has been applied to determine the
bond strength of FRP externally reinforced concrete elements. A bond strength model
based on the fracture energy approach is proposed and statistical analyses have been
developed in order to calibrate numerical factors. Thus, mean and characteristic
provisions for the debonding load in concrete elements externally bonded with CFRP
materials are furnished
Modelling of Tension Stiffening behaviour of RC ties strengthened with FRP sheets
No full textA model to analyze the behavior of reinforced concrete tension ties strengthened with fiber reinforced plastic (FRP) laminates
is developed that allows introduction of a nonlinear constitutive relationship for materials and bond-slip laws at the steel and FRP
interface. Experimental results are introduced and compared with analytical results confirming the model reliability. By using the model,
a numerical study is carried out to provide evidence of the influence of the amount of fibers and the tension-stiffening behavior of
strengthened elements. Considering elements with the same mechanical percentage of reinforcement but composed of different amounts
of steel and fibers, the stiffness is influenced only after steel yielding, even if the crack width is reduced by the external strengthening.
Finally, evidence is provided for the reduction of tension stiffening in strengthened elements due to reduction of crack spacing
Design provisions for crack spacing and width in RC elements externally bonded with FRP
No full textVerification of serviceability is a key issue in reinforced concrete (RC) elements; for RC elements
externally bonded with fibre reinforced plastic (FRP) laminates and sheets cracking phenomena are
usually verified by adopting the same approach used for steel RC elements. The available code provisions
for crack width and spacing in steel RC elements are reviewed in this paper in order to ascertain
the reliability of their application to RC elements strengthened with FRP sheets. Experimental results
belonging to test programmes performed by the authors and other researchers on RC elements externally
bonded with FRP were compared with existing code provisions in terms of crack width and
spacing.
A new formula for crack spacing, calibrated on the experimental results, is proposed for use in the
expression given by the published version of EC2 for calculating crack width in RC elements externally
bonded with FRP
Bond tests of partially encased composite columns
No full textThis paper deals with bond behavior at the steel-concrete interface of partially encased composite columns. The topic is especially interesting to determine the stress transfer between the two materials at sections where composite structural elements are connected, such as in a beam-column joint, and to ensure a short transfer length to attain the strength of the composite section. The few experimental tests in the technical literature usually concern other types of composite columns. The Authors therefore designed and carried out experimental bond tests to investigate the transfer mechanism and ascertain the reliability of some code provisions (Eurocode 4, 2004; New Italian Code, 2008) concerning the design value of bond strength for partially encased columns. A suitable test set-up was designed to measure the shear stresses transferred to the steel profile and the slip between the two materials, allowing compression or tension to be applied to concrete according to monotonic or cyclic load history. The test results give interesting information about the bond stress-slip relationship and bond strength; the cyclic tests highlight of the effect of seismic action and indicate considerable degradation of strength and stiffness
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