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The study of Thermal Protection Systems (TPS) is largely performed in Plasma Wind Tunnel (PWT) facilities where sample wear rate is of main interest and the knowledge of its relation with sample surface temperature desirable. The intrusive and indirect methods employed so far reduce the reliability and the accuracy of these tests. A new joined technique based on both the Surface Layer Implantation of radioactive tracers and on the emissivity-free Dual Color Infra-Red thermography allows the online measure of both the TPS wear rate and the surface temperature without any preparation (i.e. modification) of the sample. Other Ion Beam Analysis techniques like the Rutherford Backscattering Spectrometry (RBS) can be employed off-line to perform integrative, quantitative and still not intrusive analysis of TPS composition and of the structure modifications occurred during the PWT tests. In this work we present the results of a discrete wear rate measurement of an ablative TPS implanted with 7Be ions and the feasibility study of the RBS technique to investigate the oxidation of ceramic TPS.

Natural hazards pose a significant threat to historical cities which have an authentic and universal value for mankind. This study aims at codifying a multi-risk workflow for seismic and flood hazards, for site-scale applications in historical cities, which provides the Average Annual Loss for buildings within a coherent multi-exposure and multi-vulnerability framework. The proposed methodology includes a multi-risk correlation and joint probability analysis to identify the role of urban development in re-shaping risk components in historical contexts. The workflow is unified by exposure modelling which adopts the same assumptions and parameters. Seismic vulnerability is modelled through an empirical approach by assigning to each building a vulnerability value depending on the European Macroseismic Scale (EMS-98) and modifiers available in literature. Flood vulnerability is modelled by means of stage-damage curves developed for the study area and validated against ex-post damage claims. The method is applied to the city centre of Florence (Italy) listed as UNESCO World Heritage site since 1982. Direct multi-hazard, multi-vulnerability losses are modelled for four probabilistic scenarios. A multi-risk of 3.15 M€/year is estimated for the current situation. In case of adoption of local mitigation measures like floodproofing of basements and installation of steel tie rods, multi-risk reduces to 1.55 M€/yr. The analysis of multi-risk correlation and joint probability distribution shows that the historical evolution of the city centre, from the roman castrum followed by rebuilding in the Middle Ages, the late XIX century and the post WWII, has significantly affected multi-risk in the area. Three identified portions of the study area with a different multi-risk spatial probability distribution highlight that the urban development of the historical city influenced the flood hazard and the seismic vulnerability. The presented multi-risk workflow could be applied to other historical cities and further extended to other natural hazards.

The highly combustible nature of hydrogen poses a great hazard, creating a number of problems with its safety and handling. As a part of safety studies related to the use of hydrogen in a confined environment, it is extremely important to have a good knowledge of the dispersion mechanism. The present work investigates the concentration field and flammability envelope from a small scale leak. The hydrogen is released into a 0.47 m × 0.33 m x 0.20 m enclosure designed as a 1/15 – scale model of a room in a nuclear facility. The performed tests evaluates the influence of the initial conditions at the leakage source on the dispersion and mixing characteristics in a confined environment. The role of the leak location and the presence of obstacles, are also analyzed. Throughout the test, during the release and the subsequent dispersion phase, temporal profiles of hydrogen concentration are measured using thermal conductivity gauges within the enclosure. In addition, the BOS (Background Oriented Schlieren) technique is used to visualise the cloud evolution inside the enclosure. These instruments allow the observation and quantification of the stratification effects.

The paper deals with the structural behaviour of masonry arches strengthened through fibre reinforced composites with inorganic matrix (Textile Reinforced Mortar, TRM). Two innovative composites are considered: basalt fibre textile coupled with a lime-based matrix and carbon fibre textile associated with a cement-based matrix. Experimental results on bond capacity between composites and bricks and on the structural behaviour of unreinforced and extrados-reinforced, 1:2 scale masonry arches, tested under vertical load are presented. Experimental evidence is compared with outcomes obtained through an analytical model that exploits the stationarity of potential energy of acting forces within the assumption of large displacements. The effect of the reinforcement strip is taken into account retrieving the force-displacement relationship directly from experimental results of bond test. Results show that the analytical model provides a safety estimation of the peak load reached by the arch model during the test. Good agreement is found comparing the load-displacement diagram of the initial phases of the test and the estimations of the numerical model. It is highlighted that the bond force of TRM systems, experimentally determined on a straight substrate, offers capacity levels relevantly under those reached on a convex surface like the extrados of an arch.

The composition and patterns of spatial and season variability of epiphytic diatom assemblages of five intertidal species of Gelidiales (Rhodophyta) from three sampling sites off Gran Canaria (Canary Islands, Atlantic Ocean) were investigated during summer (2007) and winter (2008) seasons using scanning electron microscopy (SEM). Dominant species included Cocconeis scutellum var. scutellum, C. scutellum var. posidoniae, Grammatophora oceanica, Lichmophora eherembergi, Navicula sp. and Tabularia fasciculata and these represented 78% of the total diatom assemblage on Gelidiales. Eight of the diatom taxa, Cocconeis maxima, Amphicocconeis debesii, Cocconeis convexa, C. neothumensis var. marina, C. scutellum var. scutellum, C. scutellum var. posidoniae, Gomphonemopsis obscura and Pseudohimantidium pacificum, found in the present study represent new records for the Canary Archipelago. These species showed two distinct patterns of zonation, one in relation to their position at the intertidal area and the other relative to position on the host thalli. Although the vertical distribution of host thalli at the intertidal zone was important when considering the assemblage structure of epiphytic diatoms, the results showed that the cell abundance distribution changed more significantly when considering season rather than spatial distribution. Moreover, even though morphology of host thalli was not a determining factor, their aggregation mode had a significant influence on the abundance and distribution of microalgae. Finally, considering the growth forms of diatom communities, adnate diatoms were more abundant in turf than in clump species.

The behaviour of a SiC-fibre-reinforced composite with a graded matrix was investigated in an arc jet facility. The graded matrix was comprised of several layers of silicon carbide that transition to a mixed SiC-HfB2 top layer and was sealed with an HfB2-SiC coating. Samples were exposed to maximum specific total enthalpy hypersonic flow between 14 and 17 MJ kg−1 under stagnation pressures between 2700 and 3050 Pa for hold times of between 137 and 395 s. The resulting sample surface temperatures ranged between 1600 and 1950°C. Spectral emissivity at about 1 μm was calculated using a pyrometer capable of switching between one and two color modes and was shown to decrease with oxidation and removal of SiO2 from the surface. The impacts of the surface chemistry changes during oxidation and of active oxidation were investigated.

The formulas provided by the standards or available in the literature for the calculation of the elastic modulus don’t consider many variables that influence the results of flat jack tests such as, first of all, the influence of the wall thickness. In this paper, flat-jack tests were performed - in the laboratory - on masonry wall specimens having the same geometrical and mechanical properties but different thickness. Then, a numerical assessment by FEM was carried out in order to extend the experimental evidences to the case of masonry walls with large thickness. This study allows to more accurately predict the masonry elastic modulus by double flat-jack test and it provides important data useful for the research activity as well as for the engineering practice.

In this paper, we present an automated strategy for extracting behavioral small-signal macromodels of biased nonlinear circuit blocks. We discuss in detail the case study of a Low DropOut (LDO) voltage regulator, which is an essential part of the power distribution network in electronic systems. We derive a compact yet accurate surrogate model of the LDO, which enables fast transient power integrity simulations, including all parasitics due to the specific layout of the LDO realization. The model is parameterized through its DC input voltage and its output current and is thus available as a SPICE netlist. Numerical experiments show that a speedup up to 700X is achieved when replacing the extracted post-layout netlist with the surrogate model, with practically no loss in accuracy.

The design of a model-based Fault Tolerant Control (FTC) strategy based on Virtual Actuators (VA) in a built-in Guidance, Navigation and Control (GNC) setup is addressed for the e.Deorbit space mission. This mission, initiated by the European Space Agency (ESA), aims at removing a large defunct satellite from Earth orbit: ENVISAT. The goal of this paper is to promote academic solutions to add fault tolerance capacities against thruster faults without any change or new tuning of the already in-place GNC solution. The validation of the proposed FTC solution is assessed by a simulation campaign based on a high-fidelity nonlinear industrial simulator.

La classification du potentiel de risque de rupture (CPRR) des barrages de residus miniers est generalement definie en evaluant les pertes en vies humaines, les consequences sur les infrastructures, les valeurs environnementales et culturelles et les populations a risque. L’augmentation des risques de rupture d’une digue de retenue est determinee par une evaluation qualitative ou une modelisation 2D approfondie, considerant des limites extremes. Malgre la disponibilite de methodes d‘evaluation simplifiees/empiriques des ruptures de barrage, elles ne sont pas couramment utilisees en pratique generale. Les methodes proposees par Jeyapalan, J.K., et al (1983), Vick, S.G., et al (1991), Rico, M. et al. (2008) et Fontaine, D. et Martin, V. (2015) sont resumees selon la methodologie, les donnees et hypotheses utilisees, tout en identifiant les limites implicites de chacune. Les distances d’ecoulement des residus et volumes sortants seront prevus a l’aide de ces methodes et compares a des etudes de cas, et la precision et la pertinence des enregistrements historiques seront quantifiees. Un cadre general est propose pour identifier les methodes permettant de prevoir l’ecoulement des residus pour tout scenario de defaillance potentiel. Il est recommande de l‘utiliser comme outil d‘analyse intermediaire pour soutenir la CPRR des barrages miniers.

The ESA (European Space Agency) is currently pursuing the development of the e.Deorbit mission that will remove a large defunct satellite from Earth orbit: ENVISAT. To fulfil the mission autonomy requirements, ESA has decided to embed in the GNC (Guidance, Navigation, Control) software, fault tolerance capacities against actuator faults. The aim of this paper is to present the development and validation of a model-based fault diagnosis and tolerant control solution for such faults. The proposed solution is based on a new class of nonlinear unknown input observers, optimal in the $L_{2}$ -gain sense, and a modified version of the nonlinear inverse pseudo control allocation technique. An intensive simulation campaign conducted within a high-fidelity nonlinear industrial simulator, demonstrates the efficiency of the approach.

The European seismic code 8 (Eurocode 8) classifies buildings as planwise regular according to four criteria which are mostly qualitative and a fifth one, which is based on parameters such as stiffness, eccentricity, and torsional radius, that can be only approximately defined for multistory buildings. Therefore, such plan-regularity criteria are in need of improvement. ASCE seismic code, according to a different criterion, considers plan (or “torsional”) irregularity in a building when the maximum story drift, at one end of the structure, exceeds more than 1.2 times the average of the story drifts at the two ends of the structure under equivalent static analysis. Nevertheless, both the ASCE approach and the threshold value of 1.2 need to be supported by adequate background studies, based also on nonlinear seismic analysis. In this paper, a numerical analysis is carried out, by studying the seismic response of an existing R/C school building taken as the reference structure. Linear static analysis is developed by progressively shifting the centre of mass, until the ratio between the maximum lateral displacement of the floor at the level is considered and the average of the horizontal displacements at extreme positions of the floor at the same level matches and even exceeds the value of 1.2. Then, nonlinear dynamic analyses are carried out to check the corresponding level of response irregularity in terms of uneven plan distribution of deformation and displacement demands and performance parameters. The above comparison leads to check the suitability of the ASCE approach and, in particular, of the threshold value of 1.2 for identifying buildings plan irregularity.

Complexity pervades biological systems at any scale: from microbes to higher organisms, from individuals to populations and from communities to ecosystems. Biodiversity and community structure are strongly influenced by the complexity of those relationships, in addition to the interplaying between multiple environmental conditions. On the other hand, complexity in microcommunities has not been solved yet. For instance, the role of substrates in shaping the diversity and structure of biofouling communities is virtually unexplored Benthic microalgae living in shallow coastal regions give a reliable contribution to the dynamics of the aquatic ecosystems, in terms of primary production, oxygenic activity, and trophic processes (Mac Intyre et al., 1996). Among benthic microalgae diatoms are reported to colonize sponges (Cerrano et al., 2004a, b), hydrozoans (Bavestrello et al., 2008; Romagnoli et al., 2006), bryozoans (Wuchter et al., 2003), crustaceans (Ikeda, 1977), bivalves (Round, 1981), and vertebrates (Round, 1981; Round et al., 1990), with a high degree of specificity for some hosts. The species composition of epibenthic diatom communities seem to be influenced by the nature of substrate and by their biogeographic distribution. On the other hand, these diatoms communities appear to be composed by a limited number of genera, that can be considered fully adapted to the epibenthic lifestyle. Moreover, ecological studies on epibenthic diatom communities based on a rigorous taxonomic approach are very rare due to the small size of such organisms. Indeed, most of the species have average size less than 20 microns with taxonomic characters not resolvable in light microscopy, so the scanning electron microscopy (SEM) results the only possible approach for a correct quantitative analysis of such floristic communities. Our study, entirely based on scanning electron microscopy (SEM) investigation of diatom communities in undisturbed conditions gave us the first data on the hidden biodiversity of diatom assemblages associated to macrophytes and different invertebrates including sea urchins, gastropods, crustaceans and bivalves along Omani coasts in terms of functional classes and species composition. Preliminary results demostrated that all invertebrates and macroalgae collected along the Batinah coastal areas of Oman hosted benthic diatom communities which in both the case constituted the major element of their epibenthic microalgal flora. Significant differences in terms of cell density, specie composition and communities structure were observed between the diatom communities of invertebrates and macroalgae which appear quite similar within sampling locations analyzed . More in detail, cell densities of macroalgae diatom communities resulted more than one ten times higher than those of invertebrates with mean values approximately ranging 1000-4000 cell/mm2 in the former versus 100 - 400 cell/mm2 in the latter. Noteworthy is that the specie composition of macroalgae diatom communities was characterized by the complete dominance of adnate genus Cocconeis (represented by four species). Claim and gastropod diatom communities seem to be dominated still by the adnate genera Amphora and Cocconeis with a higher contribution of the former in claim and of the latter in gastropods respectively. Corals and sea urchins seem able to actively contrast diatom settlement by means of self-excreted mucilaginous matrices that trap the individual cells. Nevertheless, some genera of motile (Mastogloia, Navicula, Diploneis Nitzschia and Pleurosigma) and erect (Achnanthes, Licmophora) diatoms manage to colonize this complex and dynamic habitat.

Correct determination of masonry deformability is fundamental for evaluating the seismic response of masonry structures. For existing buildings, double flat-jack tests are largely used to estimate elastic modulus, but many problems arise for a reliable interpretation of the test outcomes. Formulas provided by standards or available in the literature follow different approaches, the results of which are strongly variable. Furthermore, these formulas do not take into consideration important practical aspects of the test apparatus, like the position of the measurement reference points in the masonry sample. The arrangement of the gauge points can influence the displacement measurements and, consequently, the value of elastic modulus. This work aims at numerically investigating—through finite element (FE) models—the effects of the position of the gauge points on the outcomes of a double flat-jack test. In particular, a continuous FE mode is adopted, in which the concrete damage plasticity model implemented in Abaqus code is used to model the nonlinear behavior of the masonry. This study provides recommendations on the correct way to determine reliable values of elastic modulus from double flat-jack testing. Furthermore, numerical results and their comparison with experimental data allow for important considerations with regard to both the research field and professional and practical activities.

We present a numerical scheme for the identification of compact surrogate models of analog circuit blocks. The basic assumption is small signal operation, so that a local linearization can be applied around a given bias point, resulting in a bias-dependent linear state-space behavioral macromodel. The main novel contribution of this work is the ability to embed in the identification process a suitable set of constraints, that are able to guarantee the uniform stability of the model for any bias value within a prescribed design range.

INTRODUCTION: THE ALLURE OF THE RINGED PLANETS One of the most enduring symbols of space exploration is a planet surrounded by a ring. This symbol inspires a celestial context: nothing on Earth is like it. It has been a wonderful surprise that the ringed planets are just as beautiful and scientifically compelling seen close up. Furthermore, the ringed planets are not just objects of beauty, but complicated physical systems that provide a local laboratory and analogy for other cosmic systems like galaxies and planet-forming disks. For a general review, see Esposito (2014). For more details, see the individual chapters that follow in this book. We now know that planetary rings, once thought unique to the planet Saturn, exist around all the giant planets. These rings are not solid objects, but are composed of countless particles with sizes from specks of dust to small moons. For each planet, the rings are quite different. Jupiter's ring is thin and composed of dust-like small particles. Saturn's rings are broad, bright, and opaque. Uranus has narrow, dark rings among broad lanes of dust that are invisible from Earth. Neptune's rings include incomplete arcs restricted to a small range of their circumference. All rings lie predominantly within their planet's Roche limit, where tidal forces would destroy a self-gravitating fluid body. They are also within the planet's magnetosphere and, in the case of Uranus, they are within the upper reaches of the planetary atmosphere. The common occurrence of ring material around the outer planets is one of the major scientific findings of the past 40 years. The new ring systems were discovered by both spacecraft and ground-based observers, often surprising us by contradicting our expectations. The rings’ appearance and composition differ among the various planets, and likewise within each ring system. The broadest set of rings and the most identified processes are found around the planet Saturn, which has been scrutinized by the US/European Cassini space mission since 2004.

Background Over the last few decades, patients have increasingly been searching for health information on the Internet. This aspect of information seeking is important, especially for people affected by chronic pathologies and require lifelong treatment and management. These people are usually very well informed about the disease but are nonetheless vulnerable to hopes of being cured or saved, often amplified by misinformation, myths, legends, and therapies that are not always scientifically proven. Many studies suggest that some individuals prefer to rely on the Internet as their main source of information, often hindering the patient-doctor relationship. A professional approach is imperative to maintain confidentiality, honesty, and trust in the medical profession. Objective we aimed to examine, in a medically supervised Italian web community (SMsocialnetwotk.com) dedicated to people with Multiple Sclerosis (pwMS), the posts shared by users and to verify the reliability of contents of posts shared by users pinpointed as Influencers through an online questionnaire. Methods we grouped the posts published on SMsocialnetwork from April to June 2015 into those with medical content (scientifically correct or fake news), and those related to social interactions. Later, we gave a questionnaire to the community asking to identify the three users/Influencers providing the most reliable advice for everyday life with MS and the three users/Influencers providing the most useful information about MS treatments. Results 308 posts reported scientific and relevant medical information, whereas 72 posts included pieces of fake news. 1420 posts were of general interest. Four out of the 6 Influencers had written only posts with correct medical information (3 were pwMS, 1 was a Neurologist) and never any fake news. The remaining 2 appointed Influencers (2 pwMS) had written only posts about general interests. Conclusion the identification of fake news and their authors has shown that the latter are never appointed as Influencers. SMsocialnetwork.com acted as a “web safe environment” where the Influencers contributed by sharing only correct medical information and never fake news. We speculate that the presence of neurologists and psychologists supervising the information flow might have contributed to reduce the risk of fake news spreading and to avoid their acquisition of authoritative meaning.

Mechanical characterization of concrete is an important step in the knowledge process aimed at assessing RC existing buildings. In particular, concerning structural response of an existing building subject to severe actions, such as the seismic ones, it is important to accurately define the concrete constitutive law, including both the compressive and the tensile branch. Definition of these mechanical properties is usually achieved through laboratory tests, mostly involving cores drilled from the building under investigation. While the compression tests are easy to perform, execution of the tensile tests is more difficult to implement. In this case, indirect tests are usually performed, such as the bending test or the splitting test. The paper presented herein concerns results of both compression and tensile tests (splitting tests) carried out on cores belonging to structures (beams and columns) of a school building located in Tuscany. Each core was interested by both types of tests: the central part of the specimen was used for the direct compression test, while the remaining end portions, resulting from the core preparation, were used for the execution of the splitting test; in this way, specimens involved in tensile tests were about twice those employed for the compression tests. Finally, results provided by laboratory tests were subjected to a subsequent re-elaboration mainly concerning the tensile strength, in order to make a comparison with strength values provided by formulations present in the technical and scientific literature.

We present a general framework for the construction of guaranteed stable and passive multivariate macromodels from sampled frequency responses. The obtained macromodels embed in closed form the dependence on external parameters, through a data-driven approximation of input data samples based on orthogonal polynomial bases. The key novel contribution of this work is an extension to the multivariate and possibly high-dimensional case of Hamiltonian-based passivity check and enforcement algorithms, which can be applied to enforce both uniform stability and uniform passivity of the models. The modeling flow is demonstrated on a representative interconnect example.

The paper presents results of a study on mechanical characterization of the historical masonry walls in L’Aquila region (central Italy), heavily damaged by the 2009 earthquake. Five recurrent types of wall textures are identified and characterized by the stonework sections, and flat-jack tests were carried out on representative walls in order to investigate the mechanical properties. Experimental results showed a good agreement with the estimation determined through a method for the assessment of masonry quality based on a Masonry Quality Index. The study permitted the collection of data useful for designing the seismic improvement of historical masonry buildings.

The seismic assessment of existing buildings is an essential issue of seismic engineering. This work is focused on the evaluation of the seismic performance of existing RC buildings according to the current Italian Technical Code, which almost coincides with the European Eurocode 8. Alternative types of analyses, all consistent to the Code provisions, have been performed with reference to a case-study, that is a real RC hospital building. An accurate knowledge of the building has been achieved, as a result of a collaboration between the University of Florence and the Regional Government. Both elastic and inelastic modeling, as well as static and dynamic ones, have been adopted in the analysis. The global response—with special attention to torsional effects—and the seismic performance of each single member have been found with all the performed analyses. The comparison among the analyses has been performed in terms of both global and local response parameters, and the reliability of each analysis has been pointed out.

Existing building structures can easily present material mechanical properties which can largely vary even within a single structure. The current European Technical Code, Eurocode 8, does not provide specific instructions to account for high variability in mechanical properties. As a consequence of the high strength variability, at the occurrence of seismic events, the structure may evidence unexpected phenomena, like torsional effects, with larger experienced deformations and, in turn, with reduced seismic performance. This work is focused on the torsional effects related to the irregular stiffness and strength distribution due to the concrete strength variability. The analysis has been performed on a case-study, i.e., a 3D RC framed 4 storey building. A Normal distribution, compatible to a large available database, has been taken to represent the concrete strength domain. Different plan layouts, representative of realistic stiffness distributions, have been considered, and a statistical analysis has been performed on the induced torsional effects. The obtained results have been compared to the standard analysis as provided by Eurocode 8 for existing buildings, showing that the Eurocode 8 provisions, despite not allowing explicitly for material strength variability, are conservative as regards the estimation of structural demand.

A key problem associated with structural health monitoring (SHM) is the placement of sensors upon a structure to detect the existence, location, and the extent of any damage. Because input data coming from the sensors are groups of measurements, it is arguable that the most widely used approach to SHM nowadays is to consider it as a statistical pattern recognition problem. Artificial neural networks have made a great impact on pattern recognition practice. A problem associated with this monitoring strategy is to find a good compromise between the quality of information achieved by the sensor network, increasing with the sensor density, and the need to keep the minimum weight and instrumentation cost. Thus, the number of sensors must be kept under control, and a search of the optimal location of such sensors needs to be performed. All these aspects have been taken into account in the present work, dealing with the problem of optimum sensor placement for impact location on a multilayered composite structure. Multilayered composite structures may suffer particularly relevant trauma when subject to low-velocity impacts, as they may produce non-visible or barely visible damage on the structure surface, while remarkable subsurface delaminations may be present. Such hidden damage, when remaining undetected, may grow to catastrophic failure. To overcome this issue, a neural network approach has been used here to predict the impact locations on a composite panel from time-dependent data recorded on a set of surface-mounted piezoelectric sensors during an experimental impact test. A genetic algorithm has been used to find the optimal sensor layout that minimised the error in predicting the impact location. A new approach, based on trilateration, is discussed and compared with the traditional one and is shown to provide the same degree of accuracy at reduced computational cost.

An aero-thermo-chemical model is developed to simulate the flowfield, including ionization, around atmospheric re-entry configurations, and its interactions with radio-frequency communication signals (e.g. GPS). The model is successfully validated against literature in-flight measurements of the electron number density, and then applied to the re-entry of recently proposed concepts of slender configurations. The advantages of using sharp and slender geometries for re-entry applications, with respect to radio communication problems, are analyzed and discussed. In addition, an experimental test-bed in an arc-jet plasma wind-tunnel has been setup to reproduce on ground the plasma- radiofrequency interaction. The capability to duplicate on-ground the ionization levels encountered during re-entry has been successfully demonstrated. A numerical model of an Argon plasma jet in chemical and thermal non-equilibrium has also been developed, for numerical rebuilding of the experiments. Both electron number densities and electron temperatures have been successfully correlated, demonstrating the ability of arc-jet facilities, integrated with proper numerical tools, to correctly deal with problems of communication attenuation/black-out.

We have chemically modified the frustules of the marine diatom Coscinodiscus concinnus Wm. Smith to properly bind a highly selective bioprobe such as an antibody. By measuring the changes in the photoluminescence emission of diatoms frustules, we have monitored the molecular recognition event between the antibody and its ligand: the dissociation constant estimated is of the same order of that measured by standard Biacore®. The nanostructured silica frustules, a low-cost and natural available material, have shown high sensitivity, equal to 1.2 ± 0.2 nm μM-1, and a detection limit of 100 nM, and thus are quite ideal candidates for lab-on-particle applications. © 2008 Elsevier B.V. All rights reserved.

Mechanical properties of concrete can consistently affect the seismic performance of RC buildings. A proper determination of the concrete strength is therefore essential for a reliable modeling of the structure. The current European Technical Code, Eurocode 8, provides a criterion for the strength assumption related to the knowledge level of the structure, which does not take into account the variability of the strength. If the concrete strength is affected by a large variability, the conventional strength value suggested by Eurocode 8 can be not conservative, since it does not consider the possible torsional effects due to a not homogeneous strength distribution and the reduced capacity of the weaker members. In this paper the effects of the concrete strength variability on the seismic performance are investigated with a case study, that is a 4-storeys 3D framed building. The seismic response of the case study by assuming different amounts of strength variability has been compared with the Eurocode 8 previsions, both in terms of possible torsional effects and seismic performance.

A proper assumption of the concrete strength is essential to model existing RC structures; their seismic performance, in fact, can be affected by the poor quality of materials, both in terms of low strength and high variability. This paper considers the effects of the variability of concrete strength within buildings. Due to the high variability of concrete strength, in fact, buildings can experience irregular seismic responses, both in plan and in elevation. This research investigates the effects of irregularity in elevation due to the strength variability of concrete in a case study, namely a four-storey RC framed building, designed for vertical loads only. The variability of the concrete strength has been evaluated on the basis of an extensive survey carried out by the REGIONE TOSCANA (Tuscany Regional Government) on a large sample of RC framed buildings. Special attention has been paid to the adequacy of current codes provisions (Eurocodes, FEMA) on how to quantify concrete strength.

A proper characterization of concrete strength is essential to correctly model existing RC structures, whose seismic performance is affected by the poor quality of materials. The purpose of this work is to evaluate the effect of incorrect assumptions for concrete strength and the adequacy of current Codes provisions (Eurocodes, FEMA). Even the effects of the non homogeneity of concrete strength within the building is considered due to its high variability; in fact, buildings can experience an irregular seismic response, both in plan and in elevation. In this work the effects of irregularity in plan due to the strength variability of concrete is analyzed on a case study, a four storey RC framed building, designed for vertical loads only. The variability of concrete strength has been evaluated using the data of an extensive investigation developed by REGIONE TOSCANA on a large sample of RC framed buildings.

Objective The aims of the present study were to examine psychometric properties of the Spielberger State-Trait Anxiety Inventory (STAI-Y-1 and STAI-Y-2, respectively) in a Multiple Sclerosis (MS) population and to identify a cut-off score to detect those MS patients with high level of state and/or trait anxiety who could be more vulnerable to development of depression and/or cognitive defects. Material and methods The STAI-Y-1 and STAI-Y-2 was completed by a group of patients (n = 175) affected by MS and a group of healthy subjects (n = 150) matched for age, educational level, and gender. In MS patients internal consistency, divergent and discriminant validities were evaluated. Construct validity was examined by exploratory factor analysis for each scale. Results There was no missing data, no floor or ceiling effects for both scales. The two scales showed high internal consistency, good divergent, and Known-groups validities. To identify high levels of state and trait anxiety in a patient with MS, we proposed three gender specific screening cut-off values (1, 1.5, 2 SD) for the STAI-Y-1 and the STAI-Y-2. Conclusions The findings showed that the STAI-Y-1 and the STAI-Y-2 are a valid tool for clinical use in MS patients and can be useful to measure the severity of anxiety and to identify those patients with high anxiety to introduce them in specific non-pharmacological intervention.

It is well known that the axial load plays an important role in the evaluation of the structural capacity of RC columns. In existing buildings this problem can be even more significant than in new ones, since the material can easily present poor mechanical properties. The paper is aimed at the investigation of the role of the axial load variation on the seismic performance of RC columns of a case-study, i.e. a doubly symmetric 4-storey RC building. The effects of the axial load variation have been checked on the first storey columns, by comparing the seismic response, measured in terms of chord rotation and shear force, with the corresponding capacity. The sensitivity of the seismic performance to the axial load is evaluated with special attention on the type of analysis adopted to determine the seismic response and on considering a wide range of values for the concrete strength. The study points out a non-negligible effect of the axial load variation on the seismic response of the case-study building, especially when combined to concrete strength variability.

An ultra-high-temperatureZrB2–SiC ceramic nose cone was tested in an arcjet plasma torch facility for 10min at temperatures above 2000 C. The nose cone model was obtained from a hot-pressed billet via electrical discharge machining.The relevant portions of themodels directly exposed to the hot streamwere analyzedby scanning electron microscopy and energy-dispersive spectroscopy. The posttest cross sectioning of the model showed a nonnegligible surface recession on the tip of the nose. Nonetheless, the material exhibited a promising potential to withstand severe reentry conditions with temperatures exceeding 2000 C in a single-use application. Spectral directional emissivity evaluationswere performed on the fly during the test bymeans of thermography coupledwith dual-color pyrometer. The numerical calculations, which simulated the chemical nonequilibrium flow around the model assuming a low catalytic surface behavior, are in good accordance with the experimental results.

Arc-jet experiments in high enthalpy hypersonic (Mach 3) non equilibrium flow were carried out on a HfB2 composite with addition of 15 vol% TaSi2, at temperatures exceeding 2000 K. The aerothermal behaviour was tested considering models having two different geometries, i.e. hemispheric and cone-shaped. The surface temperature and emissivity of the material were evaluated during the tests. Numerical computations of the nozzle flow were carried out in order to identify the flow conditions around the model and to analyze the details of thermal heating. The chemicalphysical modifications were analysed after exposures. The surface emissivity changed from 0.85 to 0.5 due to surface oxidation. The maximum temperatures reached on the tip were strongly dependent on the sample geometry, being around 2300 K for the hemisphere and 2800 K for the cone. Post test SEM analyses confirmed an excellent stability for this HfB2-based material.

The aim of this study was to review our 18-year experience in the treatment of viable hydatid liver cysts (HLCs) with double percutaneous aspiration and ethanol injection (D-PAI) and to provide indications for the clinical management of HLCs.From January 1989 to December 2007, 127 patients (100 males; 13-80 years) with 184 viable HLCs (137 univesicular, 47 multivesicular; 2.8-20 cm) underwent D-PAI.Ultrasonography (US) showed complete disappearance of 125/184 (68%) cysts; in the remaining 59 cases, an inactive solid (37 cases, 20%) or liquid pattern (22 cases, 12%) was observed with volume decreases of 50-80%. The final US pattern was unmodified during the follow-up in 96.8%. Local recurrences were observed in 5 patients (3.9%): 4 patients with 8 multivesicular cysts and 1 patient with a bilocular cyst (with a solid pattern on US) that ruptured into the biliary tree 2 years after the procedure and disappeared after endoscopic sphincterectomy. The mortality rate was 0.8%, and the overall morbidity was 8.6%. The mean hospital stay was 2.9 days. The time of healing for smaller cysts (5 cm) was shorter than that of large cysts (≥5 cm) (P 0.001).Our long-term results confirm the high effectiveness of D-PAI in the treatment of HLCs. These results suggest that multilocular cysts require closer follow-up than unilocular cysts.Sommario SCOPO: Scopo di questo studio è stato quello di riportare i risultati a lungo termine del trattamento percutaneo delle cisti idatidee epatiche con doppia puntura – aspirazione – e iniezione di etanolo/(D-PAI). MATERIALI E METODI: Centoventisette pazienti con 184 cisti idatidee epatiche vitali (137 univescicolari, 47 multivescicolari) sono stati sottoposti a D-PAI. RISULTATI: All'esame ecografico si osservava restitutio ad integrum del parenchima epatico in 125 (68%) delle 184 cisti trattate. Per le rimanenti 59, era visibile una riduzione volumetrica del 50–80%. L'aspetto ecografico risultava immodificato per tutta la durata del follow-up nel 96,8% dei pazienti, fatta eccezione per 5 (3,9%) pazienti (4 con cisti multivescicolari, 1 con cisti biloculare) che presentavano recidive locali. CONCLUSIONI: I nostri dati confermano l'elevata efficacia della D-PAI nel trattamento percutaneo delle cisti idatidee epatiche e suggeriscono uno stretto follow-up nei pazienti con cisti multivescicolari.

Geophysical modeling of multiple geophysical parameters can take place reliably through the simultaneous joint inversion of the different geophysical domains. The desired objective is the derivation of a model expressing different geophysical properties of the Earth but, at the same time, showing consistency among the parameters. This concept, generally referred to as data integration, is widespread in geophysics but the way of achieving it is not obvious. Several authors have proposed different approaches where data, interpretation, and experience all contributed to the task. The result is that no general workflows could be defined that left ample margins for uncertainties and personal judgment.