Frequency shifts in natural vibrations in pantographic metamaterials under biaxial tests

In this paper a 2D continuum model, thought as the homogenized limit of a microstructured pantographic sheet, is studied. The microstructure is characterized by two families of parallel fibers, whose deformation measures account for bending, elongation and relative rotation of the fibers. The deformation energy density of the homogenized model depends on both first and second gradients of the displacement. Modal analysis is performed in order to assess the peculiarities of the dynamic behavior of higher gradient models, and in particular the difference, with respect to classical laminae, in the dependence of the eigenfrequencies on the stiffness

Naturwall: active timber wall for renovation of existent buildings

The renovation of old buildings is actually the challenge to cope with increased effort in order to reduce climate global change, channeling more investment and awareness in this sense, defining more experimentations and find innovative solutions. The difficulty of carrying out an intervention on the existing buildings necessarily arise from the lack of information on the existing structure and the lack of coordinated processes between the multidisciplinary skills involved, as well as a difficulty to optimize the process that would make it even more competitive on the renovation work instead on the new construction. Naturwall is an innovative energy saving system for existent buildings by using wood in multifunctional components able to mitigate the environmental effort in building management. The project meant to introduce an industrialized design method in the renovation of existing build environment that highlights opportunities gave by "off site" production and parametric design approach, without neglecting the aesthetical values and the possibility to change the architectural image of residential and non residential constructions. The project aims to create a representative model of solution that will be promoted in Italy and widespread in other similar contex

Spatial and temporal trends in the ecological risk posed by polycyclic aromatic hydrocarbons in Mediterranean Sea sediments using large-scale monitoring data

Abstract Benthic organisms play an important role in aquatic ecosystems and are often used as indicators of toxic environments. In this study, we reconstructed the spatial and temporal trend of risk to benthic communities living in sediments of the Mediterranean Sea posed by the presence of 16 polycyclic aromatic hydrocarbons (PAHs). Moreover, the origins of PAH contamination in the sea were also investigated. The analysis included multiple steps, starting with an in-depth review of available studies (from the early 1980s to 2019) reporting PAH concentrations in sediments of the Mediterranean Sea. Subsequently, the collected data were spatialised and clustered according to the four basins of the Mediterranean as defined by the Mediterranean Strategy on Sustainable Development and the United Nations Environment Programme Mediterranean Action Plan. We employed additive models, a flexible and versatile tool for coping with non-linear trends by means of smooth functions, to estimate temporal trends in PAH concentrations. Finally, the primary origins of contamination and temporal trends in ecological risk were determined using a combination of approaches. The results indicated that PAHs in Mediterranean sediments originate primarily from biomass burning, with a contribution from combustion of coal and liquid fossil fuels, the latter being representative of sites near urban centres or harbours. A significant positive correlation between annual growth rates of PAH concentration in sediment and wildfires was found. The estimated non-linear trends of concentrations and risk showed different temporal patterns across basins. In recent years, especially in the Western Mediterranean, the estimated trends suggest PAH concentrations are posing an increasing risk. These results indicate the need for stronger efforts to achieve the objectives of the Marine Strategy Framework Directive

Removal of an Azo Textile Dye from Wastewater by Cyclodextrin-Epichlorohydrin Polymers

Native cyclodextrins (CDs), α-, β- and γ-CDs, were employed to synthetise three different cyclodextrin-based polymers using epichlorohydrin (EPI) as a cross-linker. These polymers were applied as adsorbent material to remove an azo textile dye, Direct Blue 78 (DB78), from water. The formation of inclusion complexes between the alone CDs and DB78 molecules were first studied in aqueous solutions. Then, adsorption experiments of the dye were performed by means of cyclodextrin/epichlorohydrin (CD/EPI) polymers. The effects of various parameters, such as contact time, adsorbent dosage, initial dye concentration, pH and temperature, were examined to determine the better adsorption conditions. The equilibrium isotherms and the adsorption kinetics were also analysed using opportune mathematic models. The chemical-physical characteristics and the morphology of the adsorbent polymers were, respectively, observed by differential scanning calorimetry and field emission scanning electron microscope. The CD/EPI polymers showed a very good ability in the removal of DB78 from aqueous solution; indeed, the maximum efficiencies in the dye removal were found to be about 99% for β-CD/EPI polymer and about 97% for γ-CD/EPI polymer, at pH 6 and 25°C conditions. It is possible to assume that the good adsorbent aptitude of CD/EPI polymers is due to their double peculiarity to include the dye in the inner cavity of CDs and to adsorb the dye on their porous surfaces by physical interaction

Effects of maternal smoking on placental ultrasound and uterine-placental Doppler

PURPOSE: the study the effects of maternal cigarette smoking during pregnancy on placental maturation (calcifications) and the placental-uterine circulation, evaluated through umbilical and uterine Doppler. METHODS: prospective cohort study involving 244 pregnant women, 210 of them non-smokers and 34 smokers. Participants were submitted to four serial sonograms. The first was performed up to the 16th week of pregnancy to determine gestational age, and the other three at 28, 32 and 36 weeks for fetal biometry, evaluation of placental texture and Doppler studies of the uterine and umbilical arteries. Premature placental calcification was defined as grade III before 36 weeks. The chi2 and Fisher exact tests were used to compare placental grading, and the Mann-Whitney test to evaluate the resistance index of uterine and umbilical arteries. RESULTS: the frequency of grade III placenta and the resistance of the uterine arteries did not differ significantly between smokers and non-smokers, at all gestational ages. Umbilical artery Doppler was significantly higher in smokers than in non-smokers at 32 weeks. CONCLUSIONS: no association was found between cigarette smoking and premature placental calcification. Smoking was associated with increased umbilical artery resistance at 32 weeks.OBJETIVO: avaliar as repercussões ultra-sonográficas do tabagismo materno na placenta, com ênfase no seu grau de maturação (calcificação), e correlacionar estes achados com o padrão hemodinâmico útero-placentário com uso da doplervelocimetria das artérias uterinas e umbilicais. MÉTODOS: estudo prospectivo do tipo coorte envolvendo 244 gestantes, sendo 210 não-fumantes e 34 fumantes. Cada paciente submeteu-se a quatro exames ecográficos sendo o primeiro até a 16ª semana, para datar a gestação. Subseqüentemente, na 28ª, 32ª e 36ª semana, foram efetivadas novas ultra-sonografias para biometria fetal, avaliação da ecotextura placentária e estudo doplerfluxométrico das artérias uterinas e umbilicais. O achado ultra-sonográfico de placenta grau III antes da 36ª semana foi considerado como calcificação precoce. Para análise estatística foram aplicados os testes do chi2 e o exato de Fisher na avaliação comparativa dos graus placentários, e o teste de Mann-Whitney para o índice de resistência das artérias uterinas e umbilicais. RESULTADOS: não foram observadas diferenças significantes na freqüência de placenta grau III e no índice de resistência das artérias uterinas entre as fumantes e não fumantes, nas diferentes idades gestacionais. O índice de resistência da artéria umbilical na 32ª semana foi significantemente maior nas tabagistas (0,64 versus 0,61, p<0,05). CONCLUSÕES: não se evidenciou associação do tabagismo com aceleração da maturação placentária. Neste estudo o vício de fumar esteve associado a alterações vasculares da circulação útero-placentária apenas na 32ª semana de gravidez.Centro de Treinamento em Ultra-sonografiaUniversidade Federal de São Paulo (UNIFESP) Departamento de ObstetríciaUNIFESP, Depto. de ObstetríciaSciEL

Stress-driven AlN cantilever-based flow sensor for fish lateral line system

In this work, we report on the fabrication and characterization of stress-driven aluminum nitride (AlN) cantilevers to be applied as flow sensor for fish lateral line system. The fabricated structures exploit a multilayered cantilever AlN/molybdenum (Mo) and a Nichrome 80/20 alloy as piezoresistor. Cantilever arrays are realized by using conventional micromachining techniques involving optical lithography and etching processes. The fabrication of the piezoresistive cantilevers is reported and the operation of the cantilever as flow sensor has been investigated by electrical measurement under nitrogen flowing condition showing a sensitivity to directionality and to low value applied forces

Closed loop control of laserwelding using an optical spectroscopic sensor for Nd:Yag and CO2 lasers

Recent developments in laser joining show the applicability of spectral analysis of the plasma plume emission to monitor and control the quality of weld. The analysis of the complete spectra makes it possible to measure specific emission lines which reveal information about the welding process. The subsequent estimation of the electron temperature can be correlated with the quality of the corresponding weld seam. A typical quality parameter, for laser welds of stainless steel, is the achieved penetration depth of the weld. Furthermore adequate gas shielding of the welds has to be provided to avoid seam oxidation. In this paper monitoring and real-time control of the penetration depth during laser welding is demonstrated. Optical emissions in the range of 400nm and 560nm are collected by a fast spectrometer. The sensor data are used to determinethe weld quality of overlap welds in AISI 304 stainless steel sheets performed both with CW Nd:YAG and CO2 lasers. A PI-controller adjusts the laser power aiming at a constant penetration. Optical inspection of the weld surface and microscopic analysis of weld cross sections were used to verify the results obtained with the proposed closed-loop system of spectroscopic sensor and controller

The Romance Inter-Views : Syntax

The Romance Inter-Views are short, multiple Q&A pairs that address key issues, definitions and ideas regarding Romance linguistics. Prominent exponents of different approaches to the study of Romance linguistics are asked to answer some general questions from their viewpoint. The answers are then assembled so that readers can get a comparative picture of what's going on in the field.For the first Inter-Views we selected (morpho-)syntactic research, and asked 8 syntacticians, representing four approaches to the study of Romance linguistics, to answer our questions. The approaches we selected are Cartography, Distributed Morphology, Minimalism, and Nanosyntax. The scholars we interviewed are listed hereafter.For Cartography:Luigi Rizzi, professor of Linguistics at the Collège de France;Norma Schifano, lecturer in Modern Languages at the University of Birmingham. For Distributed Morphology:Karlos Arregi, associate professor in Linguistics at the University of Chicago;Andrés Saab, associate researcher at CONICET, Buenos Aires and associate professor in Linguistics at the University of Buenos Aires. For Minimalism:Grant Armstrong, associate professor of Spanish Linguistics at the University of Wisconsin-Madison;Caterina Donati, professor of Linguistics at the CNRS Laboratoire de Linguistique formelle, Université de ParisFor Nanosyntax:Karen De Clercq, CNRS researcher at the Laboratoire de Linguistique formelle (Université de Paris).Antonio Fábregas, professor of Linguistics at UIT, The Arctic University of Norwa

Assessment of Climate Change Impacts in the North Adriatic Coastal Area. Part II: Consequences for Coastal Erosion Impacts at the Regional Scale

Coastal erosion is an issue of major concern for coastal managers and is expected to increase in magnitude and severity due to global climate change. This paper analyzes the potential consequences of climate change on coastal erosion (e.g., impacts on beaches, wetlands and protected areas) by applying a Regional Risk Assessment (RRA) methodology to the North Adriatic (NA) coast of Italy. The approach employs hazard scenarios from a multi-model chain in order to project the spatial and temporal patterns of relevant coastal erosion stressors (i.e., increases in mean sea-level, changes in wave height and variations in the sediment mobility at the sea bottom) under the A1B climate change scenario. Site-specific environmental and socio-economic indicators (e.g., vegetation cover, geomorphology, population) and hazard metrics are then aggregated by means of Multi-Criteria Decision Analysis (MCDA) with the aim to provide an example of exposure, susceptibility, risk and damage maps for the NA region. Among seasonal exposure maps winter and autumn depict the worse situation in 2070–2100, and locally around the Po river delta. Risk maps highlight that the receptors at higher risk are beaches, wetlands and river mouths. The work presents the results of the RRA tested in the NA region, discussing how spatial risk mapping can be used to establish relative priorities for intervention, to identify hot-spot areas and to provide a basis for the definition of coastal adaptation and management strategies.publishedVersio