Seismic Performance Evaluation of Timber-framed Masonry Walls. Experimental Tests and Numerical Modelling

This book presents a selection of the best papers from the HEaRT 2013 conference, held in Cosenza, Italy, which provided a valuable forum for engineers and architects, researchers, and educators to exchange views and findings concerning the technological history, construction features, and seismic behavior of historical timber-framed walls in the Mediterranean countries. The topics covered are wide ranging and include historical aspects and examples of the use of timber-framed construction systems in response to earthquakes, such as the gaiola system in Portugal and the Bourbon system in southern Italy; interpretation of the response of timber-framed walls to seismic actions based on calculations and experimental tests; assessment of the effectiveness of repair and strengthening techniques, e.g., using aramid fiber wires or sheets; and modelling analyses. In addition, on the basis of case studies, a methodology is presented that is applicable to diagnosis, strengthening, and improvement of seismic performance and is compatible with modern theoretical principles and conservation criteria. It is hoped that, by contributing to the knowledge of this construction technique, the book will help to promote conservation of this important component of Europe’s architectural heritage

Thrombotic and hemorrhagic complications in idiopathic erythrocytosis

We report clinical features of a large cohort of patients with IE compared to a cohort of patients with PV, focusing on the thrombotic and hemorrhagic risk

Effect of the dispersion of the chromophore on the optical performances of polarizers from polyethylene and 5”-thio-(3-butyl)nonyl-2,2’:5’,2”-terthiophene

A new polyethylene-compatible terthiophene chromophore, 5"-thio-(3-butyl) nonyl-2,2':5',2"-terthiophene, with melting point lower than 0degreesC was prepared and used for linear polarizers based on ultra-high-molecular-weight polyethylene (UHMWPE). Differential scanning calorimetry and scanning electron microscopy indicate that the new chromophore is dispersed uniformly in films of UHMWPE obtained by casting from solution. The films show excellent dichroic properties (dichroic ratio 30) at rather low drawing ratio (approximate to20). Moreover, qualitative agreement is observed with the Ward pseudo-affine deformation schem

Linear low density polyethylene (LLDPE) films containing perylene dyes as stress-strain luminescent indicators

Linear low density polyethylene (LLDPE) films containing different concentrations of perylene (P) chromophores have been prepared by solution-casting and compression-moulding. The light emission features of the films depend on P concentration and polymer films deformation. A well-defined band attributed to the formation of micro/ nano-structured perylene chromophoric aggregates is observed with more than 0.1 wt.% of P in the film. The occurrence of this phenomenon changed the emission colour of the films from a bright blue (non- interacting dyes) to low intense pale yellow (interacting dyes) colour. During film drawing the LLDPE macromolecules reorganization is able to break the P supramolecular organization, leading to the prevalence of the blue emission of monomeric P. The optical behaviour of perylene dyes acting as internal stress- strain luminescent indicators for polyethylene films, provides a powerful tool to detect macromolecular organization

Julolidine fluorescent molecular rotors as vapour sensing probes in polystyrene films

We introduce a new sensing polymer system for detection of volatile organic compounds (VOCs) based on the optical response of polystyrene (PS) films doped with julolidine fluorescent molecular rotors (FMRs). The julolidine FMRs exhibited viscosity-dependent changes in the fluorescence intensity, that was enhanced when glycerol was added to ethanol solutions and when they were dispersed in PS films. Thus, reduction in medium mobility slowed down internal motions and allowed for a major radiative decay pathway. The FMR/PS films were exposed to several VOCs, and showed a significant decrease in fluorescence emission when exposed to chloroform, whereas a negligible variation in their emission occurred when methanol was utilized. This vapour sensing behaviour was much more evident when a perfluorodecyl chain was linked to the julolidine core being the molecule segregated at the film surface. This responsive behaviour was affected by solvent composition and its reproducible response was easily determined by luminescence experiments

Vapochromic features of new luminogens based on julolidine-containing styrene copolymers

We report on vapochromic films suitable for detecting volatile organic compounds (VOCs), based on new polystyrene copolymers containing julolidine fluorescent molecular rotors (JCAEM). Poly(styrene-co-hydroxyethylmethacrylate) copolymers functionalized with cyanovinyl-julolidine moieties of different compositions were prepared, (P(STY-co-JCAEM)(m) with m = 0.06-0.61). The sensing performance of the spin-coated copolymer films demonstrated significant vapochromism when exposed to VOCs characterized by high vapour pressure and a favourable interaction with the polymer matrix, such as Et2O and CH2Cl2. It is worth mentioning that the fluorescence decrease rate was 7 times faster than that of previously investigated julolidine-based fluorescent molecular rotors dispersed in PS films. This phenomenon was attributed to the better control of the JCAEM moiety distribution in the polymer matrix conferred by the covalent approach, combined with a minimal film thickness of 4 microns. These factors, in concert, strongly accelerate the deactivation pathways of the JCAEM units in the presence of VOCs which interact well. Overall, the present results support the use of julolidine-enriched styrene copolymers as effective chromogenic materials suitable for the fast detection of VOCs

Design, Preparation, and Characterization of Thermoresponsive Hybrid Nanogels Using a Novel Ulvan-Acrylate Crosslinker as Potential Carriers for Protein Encapsulation

The aim of the present study is the design and development of thermoresponsive nanogels based on ulvan, a sulphated heteropolysaccharide of algal origins with unique biological and chemical properties. Hybrid nanogels are successfully synthesized by means of UV-initiated radical copolymerization of N-vinylcaprolactam with an ulvan derivate as a novel crosslinker. In nanogels, the ulvan-grafted poly(N-vinylcaprolactam) chains represent the thermoresponsive component. The most promising candidates, selected after a thorough physical-chemical characterization of nanogels in terms of size and responsivity to thermal variation at physiological conditions, are loaded with bovine serum albumin (BSA) as model bioactive compound. The developed nanogels display BAS loading efficiency values similar to those obtained by using synthetic crosslinkers, and thus indicating the suitability of the developed ulvan-acrylate to act as novel macromolecular crosslinker for thermoresponsive nanogels preparation

Statistical properties and morphology of a 2D gel network at the air/water interface

We report here a detailed characterization of the steps leading to the formation of a bidimensional gel at the air/water interface. The 2D geometry is peculiar in that it allows a continuous and controlled variation of the density of the system over a wide range. The evolution of the statistical properties of the structured network, as a function of the externally controlled density, is related to the corresponding evolution of the mechanical properties. We identified three steps in the gel formation: a first step occurs in the incubation time, in which the individual nm-sized gold nanoparticle aggregate to form quasi 1D structures of typical length of a few microns. The second step occurs in the first stages of the compression, with the growth of the branched structure, finally yielding to the onset of the infinite percolative cluster, which is related to the building of the mechanical elastic modulus. The final step identifies with the homogenization and regularization of the distribution of holes sizes, which relates to the further increase of the elastic modulus upon compression. We speculate that this study should help in the formulation of gels with desired characteristics, such as increased mechanical strength, or increased mobilit

Epoxy resin doped with Coumarin 6: Example of accessible luminescent collectors

We report on the preparation of luminescent collectors based on epoxy resins containing Coumarin 6 as fluorescent dye. Fluorescent epoxy slabs were obtained by carefully mixing from 60 to 150 ppm of the fluorophore with bisphenol A diglycidyl ether and 4,4′-methylenebis(2-methylcyclohexylamine) as curing agent. Spectroscopic (FT-IR, solid-state NMR, Raman) investigations and calorimetric analysis evidence the success of the preparation procedure in terms of slab homogeneity, fluorophore dispersibility and its role in promoting the crosslinking extent. The concentrating ability and the derived optical efficiencies of the epoxy-based collectors are determined with a properly designed set-up and result greater (∼10%) than that of poly(methyl methacrylate) concentrators with the same fluorophore and geometry. Optical efficiencies as high as 7.4% are obtained and enable the potential use of epoxy resins as bulk thermosetting materials for solar collectors