119,566 research outputs found
Piccoli ed effimeri: la difficile ricerca dell’Habitat “3170* Stagni Temporanei Mediterranei” in Liguria
No full textSono qui riportati i primi risultati di indagini vegetazionali sulla distribuzione dell'habitat 3170 "stagni temporanei mediterranei" secondo la Direttiva Europea Habitat in tutto il terrritorio ligure. Si evince che la distribuzione, influenzata molto dalle variazioni climatiche e dalle dinamiche in seno agli habitat fluviali, è estremamente limitata in tutta la Liguria
Elliptic rigid inhomogeneity with a slipping interface embedded in an infinite plate.
No full textThe object of the present paper is to provide a solution to the problem of a rigid elliptic inhomogeneity with a slipping interface in plane linear elasticity. Both cases of prescribed exter¬nal moment and prescribed rotation are considered. The solution may be used to study the interaction of the inhomogeneity with any line singularity (e.g. concentrated forces, edge dislocations, dilatation centers), stress con¬cen¬trations under the action of in-plane external loads, and all cases which may be treated as superpositions of the previous ones. In particular, it is found that under a remote uniform shear parallel to the axes, and no exter¬nal moment, the inhomogeneity behaves like an elliptic void
A unified treatment of the elliptic inhomogeneity with a slipping interface under line singularity loading
No full textMost of the problems dealing with elliptic inhomogeneities may be grouped in two classes. The problems of the first class deal with a perfectly adhering matrix inhomogeneity interface, while those of the second class assume a slip¬ping (liquid like) interface. A further grouping level may be considered, accord¬ing whether the loading system is applied to the matrix (external loading) or to the inhomogene¬ity (internal loading). In the past, a number of works have considered elliptic inhomogeneities with slipping interfaces [1 6], but, to our knowledge, no solu¬tion has been provided for an internally loaded slipping inhomogeneity. The present paper is aimed to fill this gap by considering a line singularity (LS) as the loading system in plane elasticity. LS solutions are quite general, since they can be used for dislocations, dilatation centers, concentrated forces, and con¬centrated moments, and, more generally, lead to the Green functions for this kind of problems. In addition, the present solution has the advantage of includ¬ing both cases of internal or external LS, according to the value of a single parameter
Effective transverse elastic moduli of a composite reinforced with multilayered hollow-cored fibers
No full textTELLUS. Ground deformations and their effects in the near-Earth space
No full textThis report will describe the activities carried out by the TELLUS team during 2004. They are continuing those concerning ground aseismic creep strain events, observed by the TELLUS tilt network; the ESPERIA space mission project planned and designed for studying Earth near-Earth space interactions; the construction of the particle detector ARINA to be installed on board the Russian satellite RESURS-DK1, which launch is scheduled for next autumn 2005 within the PAMELA mission. ARINA is part of the ESPERIA payload, another one being the LAZIO-EGLE magnetic andparticle instruments to be tested in space on board the InternationalSpace Station and used for collecting particle and magnetic data. Thesetwo instruments have been built during 2004 within a collaborationbetween the Universities Roma Tre, Perugia and Roma Tor Vergata, andrelated INFN branches, with the Lazio Region and Polytechnic of Moscow(MEPhI). LAZIO-EGLE thermal, vibration and electromagnetic emission testshave been performed in laboratory both in Italy and in Russia. Launch isscheduled for February 2005. During 2003, on the basis of an ITT of theEuropean Space Agency (ESA), the TELLUS team also submitted assub-contractor (the prime one being Alenia-Laben S.p.A.) the ARETUSAproposal for a General Study with title "Techniques and SpaceborneConcepts for the Study of Earth-Quake Precursors and Analysis ofAssociated Atmospheric Effects". Both these two activities concerning theARETUSA proposal and the construction of the EGLE space magnetometer willbe described in the present annual report
Synthesis and NMR Characterization of Dinuclear Fe(II) Organometallic Complexes Containing a Nonequivalently Bridging 5-Aryl Tetrazolate Ligand
No full textThe synthetic routes to the formation of a wide range of dinuclear Fe(II) organometallic complexes of the general formula [Cp(CO)(L)Fe-N4C-C6H4-CN-Fe(L)(CO)Cp][SO3CF3], in which the 4-cyanophenyl-tetrazolate anion N4C-C6H4-CN acts as bridging ligand, are described. 1H and 13C NMR characterization of the product complexes indicate the presence of a significant interannular conjugation effect involving the aromatic rings of the organic spacer, the extent of which can be chemically modified by addition of electrophiles such as CH3+ and H+. Furthermore, the reversibility of protonation reaction entails the opportunity of modulating the conjugative properties of the title compounds by a proton addition-elimination mechanism
Effect of Calibration Error on Bone Tracking Accuracy With Fluoroscopy
No full textModel-based 3D-fluoroscopy can quantify joint kinematics with 1mm and 1 deg accuracy level. A calibration based on the acquisition of devices of known geometry is usually applied to size the system. This study aimed at quantifying the sensitivity of the fluoroscopic pose estimation accuracy specifically to errors in the calibration process, excluding other sources of error. X-ray focus calibration error was quantified for different calibration setups, and its propagation to the pose estimation was characterized insilico. Focus reference position influenced the calibration error dispersion, while calibration cage pose affected its bias. In the worst-case scenario, the estimation error of the principal point and of the focus distance was lower than 1mm and 2 mm, respectively. The consequent estimation of joint angles was scarcely influenced by calibration errors. A linear trend was highlighted for joint translations, with a sensitivity proportional to the distance between the model and the image plane, resulting in a submillimeter error for realistic calibration errors. The biased component of the error is compensated when computing relative joint kinematics between two segments. Copyright © 2014 by ASME
Changes in the olfactory mucosa of the black bullhead Ictalurus melas induced by exposure to sublethal concentrations of sodium dodecylbenzene sulphonate
No full textThe effects of exposure to sublethal concentrations (1.5 and 3 mg l-1) of sodium dodecylbenzene sulphonate on the olfactory epithelium of Ictalurus melas Rafinesque were examined by light and scanning electron microscopy. The detergent affected the superficial part of each olfactory lamella and different morphological alterations, depending on dose and duration of treatment, were observed. The histology and surface morphology of sensory and non-sensory areas of the epithelium of fish treated with 1.5 mg l-1 for 5 and 10 d were not affected by the treatment, while only an incipient thinning-out of the long cilia of non-sensory epithelium was seen in fish treated for 15 d. Treatment with 3 mg l-1 caused morphological alterations, related to the time of exposure, in the non-sensory and sensory epithelium, consisting of progressive thinning of cellular projections; this treatment also increased mucus production. These observed histopathological changes in the olfactory mucosa may modify the olfactory perception of the fish, and could thereby impair important physiological functions such as feeding, social interactions or migration
Ultrasound-promoted hydrogelation of terpyridine derivatives
No full textTerpyridine derivatives proved to be versatile hydrogelators when subjected to ultrasound irradiation in their bis-protonated form. The chelating ability of the terpyridine ligands allows for the capture of metal cations resulting in stable gels with tunable emissive properties
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