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Airworthiness authorities require that composite materials in primary structures must be undamaged all in-service life long, resulting in an oversizing of structural components and in a general increasing of weight. To allow structures working in presence of damages but showing an acceptable residual strength, in recent years a significant interest has been pointed out in the capability of ultrasonic guided waves as candidate tool for Structural Health Monitoring (SHM) of composites. The continuous assessment of the structural integrity, that can be accomplished by means of SHM systems, would provide, in fact, a less-conservative design and significant benefits in repair operations. In this work, a description of two numerical techniques based on Finite Element Method (FEM) for the simulation of Lamb wave propagation in a damaged Glass Fibre Reinforced Polymer composite winglet is presented. The interaction between damage and guided-waves has been investigated under two central frequencies: 100 kHz and 150 kHz. Root Mean Square Deviation Damage Index has been used to compare the baseline signals (achieved under the pristine configuration) and the respective signals achieved under the impacted/damaged one. Numerical models have been assessed against an experimental tests campaign.

Aims. The iron abundance gradient in the Galactic stellar disk provides fundamental constraints on the chemical evolution of this important Galaxy component, however the spread around the mean slope is, at fixed Galactocentric distance, more than the estimated uncertainties.

In spite of the relevance of classical Cepheids as primary distance indicators, a general consensus on the dependence of the period-luminosity (PL) relation on the Cepheid chemical composition has not yet been achieved. From the theoretical point of view, our previous investigations were able to reproduce some empirical tests for suitable assumptions on the helium-to-metal relative enrichment, but these results relied on specific assumptions concerning the mass-luminosity relation and the efficiency of the convective transfer in the pulsating envelopes. In this paper, we investigate the effects of the assumed value of the mixing-length parameter $l/H_{\rm p}$on the pulsation properties and we release the assumption of a fixed mass-luminosity relation. To this purpose, new nonlinear convective fundamental pulsation models have been computed for various chemical compositions ($Z=0.004$, 0.008, 0.01 and 0.02) and adopting $l/H_{\rm p}=1.7{-}1.8$, which is larger than that (1.5) used in our previous papers. From the extended model set, synthetic PLrelations in the various photometric bands are derived using the predicted instability strip together with recent evolutionary tracks. We show that as the $l/H_{\rm p}$value increases the pulsation region gets narrower, mostly due to the blueward shift of the red edge for fundamental pulsation, with the effect becoming stronger at the higher metal contents ($Z\ge 0.01$). However, the comparison of the new models with previously computed models shows that the $l/H_{\rm p}$variation has no consequence on the predicted period-Wesenheit (PW) relations, which instead are influenced by the pulsator metal content. On this basis, we present a straightforward way to infer the distance and metal content of variables with observed BVIor BVKmagnitudes. As for the PLrelations, we show that either the zero-point and the slope are very slightly modified by the $l/H_{\rm p}$variation, at constant chemical composition. We also confirm that: (1) moving from visual to longer wavelengths, the predicted period-magnitude distribution for a given metal content becomes narrower and its slope becomes steeper; (2) decreasing the metal content, the PLrelations become steeper and brighter, with the amount of this metallicity effect decreasing from optical to near-infrared bands. Overall, we show that our pulsation relations appear fully consistent with the observed properties of Galactic and Magellanic Cloud Cepheids, supporting the predicted steepening and brightening of the PLrelations when moving from metal-rich to metal-poor variables. Moreover, we show that the distances inferred by the predicted PWrelations agree with recently measured trigonometric parallaxes, whereas they suggest a correction to the values based on the Infrared Surface Brightness technique, as already found from an independent method. Finally, also the pulsation metal contents suggested by the predicted PWrelations appear in statistical agreement with spectroscopic [Fe/H] measurements.

Aims.This work uses nonlinear convective models of RR Lyrae stars and evolutionary predictions of low-mass helium burning stellar structures to constrain the properties of cluster and field RR Lyrae variables. In particular, we address two problems: is the Period-Amplitude (PAV) plane of fundamental (RRab) variables a good diagnostic for the metal abundance? Is the MV(RR)-[Fe/H] relation of field and cluster variables linear over the whole metal abundance range of [ Fe/H$]\sim -$2.5 to ~0?

We investigate the properties of the so-called BL Her stars, i.e., Population II Cepheids with periods shorter than 8 days, using updated pulsation models and evolutionary tracks computed by adopting a metal abundance in the range of Z= 0.0001 to Z= 0.004. We derive the predicted period-magnitude (PM) and period-Wesenheit (PW) relations at the various photometric bands and we show that the slopes of these relations are in good agreement with the slopes determined by observed variables in Galactic globular clusters, independently of the adopted MV(RR)-[Fe/H] relation to get the cluster RR Lyrae-based distance. Moreover, we show that the distances provided by the predicted PMand PWrelations for BL Her stars agree within the errors with the RR Lyrae-based values. Using the predicted relations with W Vir stars, which are Population II Cepheids with periods longer than 8 days, provides no clear evidence for or against a change in the PMand PWslopes around $P \sim$10 days.

We present new grids of evolutionary models for the so-called “Anomalous” Cepheids (ACs), adopting Z= 0.0001 and various assumptions on the progenitor mass and mass-loss efficiency. These computations are combined with the results of our previous set of pulsation models and used to build synthetic populations of the predicted pulsators as well as to provide a Mass-Luminosity relation in the absence of mass-loss. We investigate the effect of mass-loss on the predicted boundaries of the instability strip and we find that the only significant dependence occurs in the Period–Magnitude plane, where the synthetic distribution of the pulsators is, on average, brighter by about 0.1 mag than the one in absence of mass-loss. Tight Period–Magnitude relations are derived in the Kband for both fundamental and first overtone pulsators, providing a useful tool for distance evaluations with an intrinsic uncertainty of about 0.15 mag, which decreases to ~0.04 mag if the mass term is taken into account. The constraints provided by the evolutionary models are used to derive evolutionary (i.e., mass-independent) Period–Magnitude–Color relations which provide distance determinations with a formal uncertainty of the order of ~0.1 mag, once the intrinsic colors are well known. We also use model computations from the literature to investigate the effect of metal content both on the instability strip and on the evolutionary Period–Magnitude–Color relations. Finally, we compare our theoretical predictions with observed variables and we confirm that a secure identification of actual ACs requires simultaneous information on period, magnitude and color, that also provide constraints on the pulsation mode.

We present theoretical predictions concerning horizontal branch stars in globular clusters, including RR Lyrae variables, as derived from synthetic procedures collating evolutionary and pulsational constraints. On this basis, we explore the predicted behavior of the pulsators as a function of the horizontal branch morphology and over the metallicity range $Z=$0.0001 to 0.006, revealing an encouraging concordance with the observed distribution of fundamentalised periods with metallicity. Theoretical relations connecting periods to Kmagnitudes and BVor VIWesenheit functions are presented, both appearing quite independent of the horizontal branch morphology only with $Z\ge$0.001. Predictions concerning the parameter Rare also discussed and compared under various assumptions about the horizontal branch reference luminosity level.

We investigate the theoretical scenario concerning the large sample of variables recently discovered in the dwarf, metal-poor irregular galaxy Leo A, focusing the attention on the “Anomalous” Cepheid phenomenon and its correlation with RR Lyrae stars, Classical and Population II Cepheids. To this purpose, we make use of suitable stellar and pulsation models to depict the pulsational history of evolutionary structures with metallicity $Z=0.0004$. We find that He-burning pulsators are expected only outside the mass interval ~0.8–1.7 $M_{\odot}$. Stars from ~1.8 to 4 $M_{\odot}$, a mass range including both Anomalousand ClassicalCepheids, populate to good approximation a common MV-logPFinstability strip, independently of the previous occurrence of a He flash event. Their periods and luminosities increase with the stellar mass and they are at a lower luminosity level $M_{V,\rm LE}\sim -0.5$mag, as observed in Leo A. The class of less massive pulsators ($M<0.8$$M_{\odot}$, namely RR Lyraestars and Population II Cepheids) populate a distinct instability strip, where the magnitudes become brighter and the periods longer when the pulsator mass decreases. The dependence on metal content in this scenario has been investigated over the range $Z=0.0002$to 0.008. The edges of the pulsational strip for the more massive class of pulsators appear to be independent of metallicity, but with a minimum mass of these bright pulsators which decreases with decreasing metallicity, thus decreasing the predicted minimum luminosity and period. Comparison with data for Cepheids in Leo A and in the moderately metal-rich extragalactic stellar system Sextans A discloses an encouraging agreement with the predicted pulsational scenario. On this basis, we predict that in a stellar system where both RR Lyrae stars and Cepheids are observed their magnitude difference may help in constraining both the metal content and the distance. The current classification of metal-poor Cepheids is briefly discussed and suggestion is advanced for an updated terminology abreast with the current knowledge of stellar evolution.

A theoretical investigation of the pulsation behavior of so-named “anomalous” Cepheids is presented. The study is based on nonlinear convective pulsation models with $Z=0.0001$and 0.0004, mass in the range 1.3-2.2 $M_{\odot}$and various luminosity levels. Based on these computations, we derive periods, bolometric light curves and the edges of the instability strip, showing that a variation of the metal abundance from $Z=0.0001$to 0.0004 has quite small effects on these quantities. Then, using bolometric corrections and color-temperature transformations, we are able to provide the predicted relations connecting pulsational properties (periods, amplitudes) with magnitudes and colors in the various photometric bands. The theoretical pulsational scenario is compared to observed anomalous Cepheids in dwarf spheroidal galaxies and, in particular, the predicted mass-dependent Period-Magnitude-Amplitude and Period-Magnitude-Color relations are used to estimate individual mass values, as well as to discriminate between fundamental (F) and first-overtone (FO) pulsators.

In this paper we revisit observational data concerning RR Lyrae stars in Galactic globular clusters, presenting frequency histograms of fundamentalized periods for the 32 clusters having more than 12 pulsators with well recognized period and pulsation mode. One finds that the range of fundamentalized periods covered by the variables in a given cluster remains fairly constant in varying the cluster metallicity all over the metallicity range spanned by the cluster sample, with the only two exceptions given by M 15 and NGC 6441. We conclude that the width in temperature of the RR Lyrae instability strip appears largely independent of the cluster metallicity. At the same time, it appears that the fundamentalized periods are not affected by the predicted variation of pulsators luminosity with metal abundance, indicating the occurrence of a correlated variation in the pulsator mass. We discuss mean periods in a selected sample of statistically significant “RR rich" clusters with no less than 10 RRab and 5 RRc variables. One finds a clear evidence for the well known Oosterhoff dichotomy in the mean period $$of ab-type variables, together with a similarly clear evidence for a constancy of the mean fundamentalized period $$in passing from Oosterhoff type II to type I clusters. On this basis, the origin of the Oosterhoff dichotomy is discussed, presenting evidence against a strong dependence of the RR Lyrae luminosity on the metal content. On the contrary, i) the continuity of the mean fundamentalized period, ii) the period frequency histograms in the two prototypes M 3 (type I) and M 15 (type II), iii) the relative abundance of first overtone pulsators, and iv) the observed difference between mean fundamental $$and fundamentalized periods $$, all agree in suggesting the dominant occurrence of a variation in the pulsation mode in a middle region of the instability strip (the “OR" zone), where variables of Oosterhoff type I and type II clusters are pulsating in the fundamental or first overtone mode, respectively.

BVIdata of Galactic Cepheids observed in the solar neighborhood and in the outer disk are analyzed on the basis of nonlinear, non-local and time-dependent convective pulsating models computed for different assumptions on the chemical composition. We show that the theoretical color-color, period-luminosity, and period-luminosity-color relations, as predicted by the models with varying metal content, provide the way to simultaneously estimate the true distance modulus $\mu_0$and the metal content Zof each individual variable. On this basis, we estimate that the metallicity distribution of Cepheids with Galactocentric distances dfrom ~6 to ~19 kpc can be represented by a linear gradient of $-0.05 \pm 0.01$dex kpc-1, which is close to previous empirical determinations based on Cepheids, Planetary Nebulae and HII regions. However, our results are not excluding a different scenario, such as a two-zone model with a discontinuity in metallicity near $d=10$kpc (see Twarog et al. 1997).

We have performed accurate iron abundance measurements for 44 red giants (RGs) in the Carina dwarf spheroidal (dSph) galaxy. We used archival, high-resolution spectra (R? 38,000) collected with UVES at ESO/VLT either in slit mode (five RGs) or in fiber mode (39 RGs, FLAMES/GIRAFFE-UVES). The sample is more than a factor of 4 larger than any previous spectroscopic investigation of stars in dSphs based on high-resolution (R?38000) spectra. We did not impose the ionization equilibrium between neutral and singly ionized iron lines. The effective temperatures and the surface gravities were estimated by fitting stellar isochrones in the V,B- Vcolor-magnitude diagram. To measure the iron abundance of individual lines we applied the LTE spectrum-synthesis fitting method using MARCS model atmospheres of appropriate metallicity. For the 27 stars for which we measured both Fe Iand Fe IIabundances, we found evidence of NLTE effects between neutral and singly ionized iron abundances. The difference is ?0.1 dex, on average, but steadily increases when moving from the metal-rich to the metal-poor regime. Moreover, the two metallicity distributions differ at the 97% confidence level. Assuming that the Fe IIabundances are minimally affected by NLTE effects, we corrected the Fe Istellar abundances using a linear fit between Fe Iand Fe IIstellar abundance determinations. We found that the Carina metallicity distribution based on the corrected Fe Iabundances (44 RGs) has a weighted mean metallicity of [Fe/H] = -1.80 and a weighted standard deviation of ? = 0.24 dex. The Carina metallicity distribution based on the Fe IIabundances (27 RGs) gives similar estimates ([Fe/H] = -1.72, ? = 0.24 dex). The current weighted mean metallicities are slightly more metal-poor when compared with similar estimates available in the literature. Furthermore, when we restricted our analysis to stars with the most accurate iron abundances, ?20 Fe Iand at least three Fe IImeasurements (15 stars), we found that the range in iron abundances covered by Carina RGs (?1 dex) agreed quite well with similar estimates based on high-resolution spectra; however, it is a factor of 2-3 smaller than abundance estimates based on the near-infrared calcium triplet. This finding supports previous estimates based on photometric metallicity indicators.

We introduce a new parameter ??-the difference in magnitude between the red giant branch (RGB) bump and the point on the main sequence (MS) at the same color as the bump (which we call the "benchmark")-to estimate the helium content in old stellar systems. The ?? parameter is a helium indicator, since an increase in helium makes, at fixed age and iron abundance, the RGB bump brighter and the MS benchmark fainter. Moreover, its sensitivity to helium is linear over the entire metallicity range. ?? is also minimally affected by changes of a few gigayears in cluster age, by uncertainties in the photometric zero point, by the amount of reddening, or by the effects of evolution on the horizontal branch. The two main drawbacks of the ?? parameter include the need for precise and large photometric data sets and a strong dependence of the ?Y/?? slope on metallicity. We selected almost two dozen relatively bright Galactic globular clusters (GGCs) with low foreground reddening and a broad range of iron abundance (-2.45 ? [Fe/H] ? -0.70 dex), together with precise and homogeneous multiband (BVI) photometry. The observed ?? parameters and those predicted from ?-enhanced evolutionary models agree reasonably well if we assume a primordial helium content of Y= 0.20 (abundance by mass). The discrepancy becomes ?4? (?B= 0.20 mag) only in the metal-poor regime. Comparison with prescriptions based on a canonical primordial helium content (Y= 0.245 indicates that the observed ?? values are smaller than predicted. These findings support previous results suggesting that current evolutionary models overestimate the luminosity of the RGB bump. The inclusion of envelope overshooting can eliminate the discrepancy. The ?? parameter of GGCs provides an independent detection of prestellar helium, at least at the 5? level.

We present new and accurate radial velocity (RV) measurements of luminous stars of all ages (old horizontal branch, intermediate-age red clump, and young blue plume, as well as red giants of a range of ages: 20.6 ? V? 22) in the Carina dwarf spheroidal galaxy, based on low-resolution spectra collected with the FORS2 multiobject slit spectrograph at the VLT. This data set was complemented by RV measurements based on medium- and high-resolution archive spectra of brighter (V? 20.6) Carina targets collected with the GIRAFFE multiobject fiber spectrograph at the VLT. The combined sample includes more than 21,340 individual spectra of ?2000 stars covering the entire body of the galaxy. The mean (?RV? = 220.4 ± 0.1 km s-1) and the dispersion (? = 11.7 ± 0.1 km s-1) of the RV distribution of candidate Carina stars (?1210 objects, 180 ? RV ? 260 km s-1, 4?) agree quite well with similar measurements available in the literature. To further improve the statistics, the accurate RV measurements recently provided by Walker et al. were also added to the current data set. We ended up with a sample of ?1370 RV measurements of candidate Carina stars that is ?75% larger than any previous Carina RV sample. We found that the hypothesis that the Carina RV distribution is Gaussian can be discarded at 99% confidence level. The mean RV across the body of the galaxy varies from ?220 km s-1at a distance of 7' (?200 pc) from the center to ?223 km s-1at 13' (?400 pc, 6? level) and flattens out to a constant value of ?221 km s-1at larger distances (600 pc, 4? level). Moreover, and even more importantly, we found that in the Carina regions where the mean RV is smaller, the dispersion is also smaller, and the RV distribution is more centrally peaked (i.e., the kurtosis attains larger values). The difference in mean RV is more than 4 km s-1(9? level) when moving from east to west and more than 3 km s-1(?7? level) when moving from north to south. The RV gradient appears to be in the direction of the Carina proper motion. However, this parameter is affected by large uncertainties to reach a firm conclusion. There is evidence of a secondary maximum in RV across the Carina center (|D| ? 200 pc). The occurrence of a secondary feature across the Carina center is also supported by the flat-topped radial distribution based on the photometric catalog. These findings are reminiscent of a substructure with transition properties that are already detected in dwarf ellipticals, and they call for confirmation by independent investigations.

We present precise and deep optical photometry of the globular M92. Data were collected in three different photometric systems: Sloan Digital Sky Survey (g', r', i', and z'; MegaCam at CFHT), Johnson-Kron-Cousins (B, V, and I; various ground-based telescopes), and Advanced Camera for Surveys (ACS) Vegamag (F475W, F555W, and F814W; Hubble Space Telescope). Special attention was given to the photometric calibration, and the precision of the ground-based data is generally better than 0.01 mag. We computed a new set of ?-enhanced evolutionary models accounting for the gravitational settling of heavy elements at fixed chemical composition ([?/Fe] = +0.3, [Fe/H] = -2.32 dex, and Y= 0.248). The isochrones-assuming the same true distance modulus (? = 14.74 mag), the same reddening [E(B- V) = 0.025 ± 0.010 mag], and the same reddening law-account for the stellar distribution along the main sequence and the red giant branch in different color-magnitude diagrams (i', g'- i'; i', and g'- r'; i', g'- z'; I, and B- I; and F814W and F475W-F814W). The same outcome applies to the comparison between the predicted zero-age horizontal-branch (ZAHB) and the HB stars. We also found a cluster age of 11 ± 1.5 Gyr, in good agreement with previous estimates. The error budget accounts for uncertainties in the input physics and the photometry. To test the possible occurrence of CNO-enhanced stars, we also computed two sets of ?- and CNO-enhanced (by a factor of 3) models, both at fixed total metallicity ([M/H] = -2.10 dex) and at fixed iron abundance. We found that the isochrones based on the former set give the same cluster age (11 ± 1.5 Gyr) as the canonical ?-enhanced isochrones. The isochrones based on the latter set also give a similar cluster age (10 ± 1.5 Gyr). These findings support previous results concerning the weak sensitivity of cluster isochrones to CNO-enhanced chemical mixtures.

We present deep, accurate, and homogeneous multiband optical (U, B, V, I) photometry of the Carina dwarf spheroidal galaxy, based on more than 4000 individual CCD images from three different ground-based telescopes. Special attention was given to the photometric calibration, and the precision for the B, V, and Ibands is generally better than 0.01 mag. We have performed detailed comparisons in the V, B- V, and V, B- Icolor-magnitude diagrams (CMDs) between Carina and three old, metal-poor Galactic globular clusters (GGCs, M53, M55, M79). We find that only the more metal-poor GCs (M55, [Fe/H] = -1.85; M53, [Fe/H] = -2.02 dex) provide a good match with the Carina giant branch. We have performed a similar comparison in the V, V- ICMD with three intermediate-age clusters (IACs) of the Small Magellanic Cloud (Kron 3, NGC 339, Lindsay 38). We find that the color extent of the subgiant branch (SGB) of the two more metal-rich IACs (Kron 3, [Fe/H] = -1.08; NGC339, [Fe/H] = -1.36 dex) is smaller than the range among Carina's intermediate-age stars. Moreover, the slope of the RGB of these two IACs is shallower than the slope of the Carina RGB. However, the ridge line of the more metal-poor IAC (Lindsay 38, [Fe/H] = -1.59 dex) agrees quite well with the Carina intermediate-age stars. These findings indicate that Carina's old stellar population is metal-poor and appears to have a limited spread in metallicity (?[Fe/H] = 0.2-0.3 dex). The Carina's intermediate-age stellar population can hardly be more metal-rich than Lindsay 38, and its spread in metallicity also appears modest. We also find that the synthetic CMD constructed assuming a metallicity spread of 0.5 dex for the intermediate-age stellar component predicts evolutionary features not supported by observations. In particular, red clump stars should attain colors that are redder than red giant stars, but this is not seen. These results are at odds with recent spectroscopic investigations suggesting that Carina stars cover a broad range in metallicity (?[Fe/H] ? 1-2 dex). We also present a new method to estimate the metallicity of complex stellar systems using the difference in color between the red clump and the middle of the RR Lyrae instability strip. The observed colors of Carina's evolved stars indicate a metallicity of [Fe/H] = -1.70 ± 0.19 dex, which agrees quite well with spectroscopic measurements.

Aims.This work uses nonlinear convective models of RR?Lyrae stars and evolutionary predictions of low-mass helium burning stellar structures to constrain the properties of cluster and field RR?Lyrae variables. In particular, we address two problems: is the Period-Amplitude (PAV) plane of fundamental (RRab) variables a good diagnostic for the metal abundance? Is the MV(RR)-[Fe/H] relation of field and cluster variables linear over the whole metal abundance range of [ Fe/H]?-2.5 to?~0? Methods.We perform a detailed comparison between theory and observations for fundamental RR?Lyrae variables in the solar neighborhood and in both Oosterhoff type?I (OoI) and type?II (OoII) Galactic globular clusters. Results.We show that the distribution of cluster RRabvariables in the PAVplane depends not only on the metal abundance, but also on the cluster Horizontal Branch (HB) morphology. We find that on average the observed pulsation parameter kpulsconnecting the period to the visual amplitude increases when moving from metal-poor to metal-rich GGCs. However, this parameter shows marginal changes among OoI?clusters with intermediate to red HB?types and iron abundances -1.8?[Fe/H]?-1.1, whereas its value decreases in OoII?clusters with the bluer HB?morphology, although these clusters are also the less metal-poor ones of the group. Moreover, at [ Fe/H]=-1.7?0.1 the OoI?clusters present redder HB?types and larger ?kpuls? values than the OoII?clusters. The RRabvariables in ??Cen and in the solar neighborhood further support the evidence that the spread in [Fe/H], at fixed kpuls, is of the order of ?0.5?dex. Using the results of synthetic HB?simulations, we show that the PAVplane can provide accurate cluster distance estimates. We find that the RRabvariables in OoI?and in OoII?clusters with very blue HB?types obey a well-defined MV(RR)?kpulsrelation, while those in OoII?clusters with moderately blue HB?types present a zero-point that is ~0.05 mag brighter. Regarding field variables, we show that with [ Fe/H]?-1.0 a unique MV(RR)?kpulsrelation can be adopted, independently of the color distribution of the parent HB?star population.Conclusions. Current findings suggest that the PAVdistribution is not a robust diagnostic for the metal abundance of RRabvariables. However, the same observables can be used to estimate the absolute magnitude of globular cluster and field RRabvariables. We show that over the metallicity range -2.4?[Fe/H]?0.0 the MV(RR)-[Fe/H] relation is not linear but has a parabolic behavior.

The behavior of the wing of an aircraft is characterized by the complex interaction among dynamic (distribution of the masses), elastic (ownership of the materials) and aerodynamic (shapes, forces and moments) phenomena. As a rule it is expected from us that the aerodynamic actions damp the oscillations (natural or forced) of the wing. However, above given speeds a lot of undesired aero‐elastic phenomena, among which the divergence of the wings, occur and became of considerable importance in view of safety. To potentially prevent dangerous situations, generally the speed of the aircraft is limited; a possible alternative is to endow the “system wing” of proper devices (passive or active, i.e. controls) in order to prevent that the energy transfer of aerodynamic actions amplifies its instability. The forward swept wings are extremely efficient in terms of aerodynamics performance (stall and supersonic behavior) and therefore of maneuverability of the aircraft, even if, unfortunately, they are extremely critic under the profile of the aero‐elastic stability. The solution of the technical‐scientific and technological problems associated with the use of innovative configurations of wings prefigures a meaningful breakthrough in the international aerospace sector. Within this work the authors aim to determine a particular configuration of composite material for the realization of a forward swept wing in such a way that, under the action of the effective aerodynamic loads, the wings structural response provides a coupled bending‐torsion deformations with stability effects. It will be shown that by using a recursive analysis of the composite lay‐up one can tailor the overall bending/torsion deformation ratio value.

Targeted therapies are causing a dramatic change in cancer drug development. Trastuzumab, a humanised recombinant monoclonal antibody that recognizes the extracellular domain of HER2 trans-membrane protein, is among the first target-specific drugs that have been licensed for clinical use and its development represents a model of integration of new agents with classical treatment strategies. In preclinical models, trastuzumab has demonstrated a marked antiproliferative effect and a synergistic action with several chemotherapeutic agents. Monotherapy trials indicate that trastuzumab is active as a single agent in HER2 positive patients, is well tolerated, and is associated with preservation of quality of life (QoL). Furthermore, as first line therapy for metastatic breast cancer overexpressing HER2 receptor, the addition of trastuzumab to taxane-based chemotherapy significantly increased rate of objective response, time to disease progression and survival when compared with chemotherapy alone. Trastuzumab has shown important activity when used with many chemotherapeutic agents such as platinum salts, gemcitabine, vinorelbine and capecitabine and liposomal anthracyclines. Various trials are now ongoing to optimize the use of trastuzumab and to investigate its role in the adjuvant and in the neo-adjuvant setting.

We report studies on the average molecular orientation state in steady and transient shear flow of two lyotropic liquid crystalline polymers:  poly(benzyl glutamate) [PBG] and hydroxypropylcellulose [HPC], both in m-cresol solution. An annular cone and plate X-ray shear cell is used to probe molecular orientation in the “1−2” plane, allowing simultaneous measurements of the degree of anisotropy and the average orientation angle relative to the flow direction. In steady shear flow, molecular orientation increases with shear rate in both materials. Comparisons with separate measurements in the “1−3” plane indicate that both materials exhibit a macroscopically biaxial orientation distribution function. The orientation angle is always small and exhibits a sign change from positive to negative values with increasing shear rate. In transient flows, anisotropy and orientation angle both exhibit damped oscillations that scale with shear strain. The Larson−Doi polydomain model is in qualitative agreement with data collected on PBG in flow reversal, but only after an initial transient response seen in the experiments over the first several strain units following the reversal. Following step-increase and step-decrease of shear rate, the Larson−Doi model makes qualitatively correct predictions of anisotropy but qualitatively incorrect predictions of the transient average orientation angle.

Flax dew-retting is widely adopted in most flax-growing countries, but it does not represent a practical solution where dry weather conditions occur after harvest. A study of the local microbiological aspects was undertaken as a contribution to improve field-retting of flax under southern European climates. Fungi were isolated from soil and dew-retted flax in northern Italy, and 23 representative strains were chosen to test their ability to ret flax stems. Experiments were performed in vitroon flax stem pieces artificially inoculated with single fungal strains. Retting degree was assessed with a mechanical test, to evaluate the ease with which the bast was detached from the wood core, and by the analysis of the residual fibre pectins using uronic acid. Uronic acid dosage provided a better differentiation of the strains than the mechanical test. There was a large variability in retting ability among the species assayed and even among strains of the same species. The best results were obtained with all Aspergillusand Penicilliumstrains, while Mucorand Rhizopusstrains showed a variable retting ability. Fusarium, Trichodermastrains and Epicoccum nigrumhad the poorest retting abilities among all the fungal strains assayed.

We present CCD photometry for stars in three fields centered on the old open cluster NGC 188 and in four fields on the intermediate-age cluster NGC 7789, which has been performed with the aim of investigating the HR diagram distribution of the cluster's Main-Sequence (MS) stars. A sufficiently well-defined sequence of subgiant, turn-off (TO), and MS stars have been detected, extending the observed lower MS down to aboutV=20 mag.

From March 1988 through March 1990, at the Philadelphia Medical Examiner's Office toxicology laboratory, samples from 77 decomposed human bodies were tested for the presence of cocaine, employing gas chromatography/mass spectrometry (GC-MS). The material analyzed included decomposed soft tissue, bloody decomposition fluid, mummified tissue, maggots, and beetle feces. Twenty-two cases (28.6%) were positive for cocaine, many of these cases in states of advanced decomposition. These findings indicate the usefulness of testing decomposed tissue for cocaine in all cases where its presence is suspected. This is contrary to what might be expected, since cocaine is generally labile and rapidly broken down by both enzymatic and nonenzymatic mechanisms.

The synthesis of controlled molecular weight semicrystalline polyimides based on 1,3-bis(4-aminophenoxy)benzene (TPER diamine) and 3,3‘,4,4‘-biphenyltetracarboxylic dianhydride (BPDA), end capped with phthalic anhydride, is reported herein. The above polyimide henceforth referred to as TPER polyimide (Mn = 20k, 30k) displayed excellent thermal stability, as evidenced by dynamic thermogravimetric analysis in both air and nitrogen atmospheres. This polyimide displayed a glass transition temperature of ca. 210 °C based on DSC measurements, and a melting temperature of 395 °C. A unique feature of this polyimide was the fact that quenching the polymer from the melt, even at very high cooling rates (ca. 200 °C/min), did not result in an amorphous polymer, implying very high crystallization rates from the melt. The subsequent melting endotherm was also shown to be extremely narrow, as evidenced by a sharp endotherm in the DSC trace, which was attributed to a narrow distribution of crystal thicknesses. On the basis of the results of the melting behavior of nonisothermally and isothermally crystallized samples, a process of melting/recrystallization has been shown to occur in the system during the DSC heating scan. This melting/recrystallization phenomenon has been shown to give rise to the observed multiple melting endotherms in the DSC scans of isothermally crystallized samples. The equilibrium melting temperature of this polymer estimated using a Hoffman−Weeks plot was shown to be 408 °C. The thermal stability of the TPER-based system has been investigated by monitoring the crystallization and melting response after residence in the melt at various times and temperatures. Melt time and temperature studies showed the exceptional thermal stability of the TPER polyimide versus corresponding results for the commercial polyimide “New TPI” and for a polyimide based on 1,4-bis(4-aminophenoxy)benzene and 4,4‘-oxydiphthalic anhydride (TPEQ polyimide). Polyimide samples with amine end groups, as well as samples partially end capped with phthalic anhydride were shown to display distinctly lower thermal stability compared to phthalimide end-grouped samples. The improved behavior was demonstrated by melt rheological and crystallization experiments.

New infrared photometry of a sample of 39 stars in the open cluster NGC 752 is presented. These observations confirm the bimodality of the Main Sequence previously reported. We analyze the nature of this behaviour on the basis of the binary hypothesis.

A topological approach in the HR diagram is given for the occurrence and the characteristics of convective envelopes in population II stars. The location of the Hayashi track and of the Red Giants branch are both investigated for various assumed masses of the stars and chemical compositions of the convective layers.

In the light of our present knowledge on stellar evolution, it is shown that red ZAHB will not develop for very low metal Globular Clusters ifY is appreciably greater than 0.1.

After a short historical survey (Section 1), present available informations on the location of H.B. stars in the colour-magnitude diagram are collected. A general agreement is found between observations and theoretical predictions as deduced from the available B.C.- and (B-V)-logTerelations. It is shown that some peculiarities or differences in the shapes of the blue branch — if real — can be ascribed to differences in the He content and/or in the efficiency of gravitational sedimentation, whereas the discrepancies in the maximum colour index of red H.B. stars is perhaps related with present indeterminacy of the treatment of superadiabacity (Section 2). Finally (Section 3) a comparison among presently available evaluations of the B.C.-logTeand (B-V)-logTerelations is made in order to derive informations about the range of reliability, as well as in order to emphasize some possible peculiarities.

From a new infrared photometry of the globular cluster M10 its interstellar extinction and distance modulus are discussed. This is done by comparison with the well-studied clusters M3, M13, and M92. Final values ofE(B-V)=0.17±0.05 and (Mv-V)=14.0±0.3 are proposed. The dependence on metallicity of these values is briefly discussed.

Aims. We provide accurate estimates of distances, radii, and iron abundances of four metal-rich Cepheids, namely V340 Ara, UZ Sct, AV Sgr, and VY Sgr. The main aim of this investigation is to constrain their pulsation properties and their location across the Galactic inner disk.Methods. We adopted new accurate NIR (J,H,K) light curves and new radial velocity measurements for the target Cepheids to determinate their distances and radii using the Baade-Wesselink technique. In particular, we adopted the most recent calibrations of both the IR surface brightness relation and the projection factor. We also provide accurate measurements of the iron abundance of the target Cepheids.Results. Current distance estimates agree to within one σwith similar distances based on either empirical or theoretical NIR Period-Luminosity (P-L) relations. However, the uncertainties in the Baade-Wesselink distances are on average a factor of 3–4 smaller than errors affecting other distance determinations. Mean Baade-Wesselink radii also agree at the one σlevel with Cepheid radii based either on empirical or theoretical Period-Radius relations. Iron abundances are, within one σ, similar to those determined by Andrievsky and collaborators, thus confirming that the target Cepheids are super metal-rich. We also found that the luminosity amplitudes of classical Cepheids, at odds with RR Lyrae stars, do not exhibit a clear correlation with their metal content. This circumstantial evidence appears to be caused by the Hertzsprung progression and the dependence of the topology of the instability strip on metallicity, evolutionary effects, and binaries.

Aims. We provide accurate estimates of distances, radii, and iron abundances of four metal-rich Cepheids, namely V340 Ara, UZ Sct, AV Sgr, and VY Sgr. The main aim of this investigation is to constrain their pulsation properties and their location across the Galactic inner disk.