246 research outputs found
Indagine sui tributi comunali in Piemonte
Contributi di ricerca ; n.200/2006- Indice #3- Introduzione #5- Struttura e dinamica del sistema dei tributi comunali in Italia e in Piemonte #11- L'indagine sul sistema dei tributi in un gruppo di Comuni piemontesi #27- Riflessioni conclusive #47- Bibliografia #4
Vibration-based monitoring and diagnosis of cultural heritage: A methodological discussion in three examples
Modern monitoring techniques contribute to accurately describing the structural health conditions of historical buildings and to optimizing the plan of maintenance as well as the restoring intervention. Particularly, dynamic testing gives knowledge about global structural behavior and can be used to calibrate numerical models and to predict the response to dynamic and earthquake loading. In some circumstances, vibration-based monitoring can also help in evaluating safety conditions. The present article proposes a discussion about the methodological multidisciplinary approach to modal testing when applied to architectural heritage buildings and structures, along with the description of selected case studies. These examples were chosen to cover the various issues connected to test design and interpretation
Identificazione dinamica sperimentale di edifici strategici sotto sisma
Edifici pubblici quali ospedali, scuole, chiese e municipi costituiscono un patrimonio di importanza strategica per la vita di una comunitĂ . La loro gestione richiede un periodico monitoraggio delle condizioni di sicurezza sia a breve che a lungo termine che puĂČ oggi essere condotto in modo efficace ed oggettivo mediante sistemi automatici e permanenti di misura delle vibrazioni strutturali. All'occorrenza di un evento sismico, tali sistemi hanno il merito di cogliere l'effettivo comportamento dinamico della struttura, permettendo la calibrazione sperimentale di modelli numerici, utili per una accurata valutazione del livello di sicurezza sismico e per la progettazione di interventi migliorativi. In quest'ottica assume particolare rilievo la rete di monitoraggio dinamico permanente di edifici strategici realizzata dal Dipartimento di Protezione Civile. Quattro di questi edifici sono stati scelti come casi studio allo scopo di analizzarne la risposta acquisita durante il recente evento sismico del Gennaio 2012 in Lunigiana/Garfagnana. Il presente articolo riporta i risultati della caratterizzazione dinamica condotta su uno di essi: il municipio di San Romano in Garfagnana (LU
Implicit Extended Kalman Filter for Optical Terrain Relative Navigation Using Delayed Measurements
The exploration of celestial bodies such as the Moon, Mars, or even smaller ones such as comets and asteroids, is the next frontier of space exploration. One of the most interesting and attractive purposes from the scientific point of view in this field, is the capability for a spacecraft to land on such bodies. Monocular cameras are widely adopted to perform this task due to their low cost and system complexity. Nevertheless, image-based algorithms for motion estimation range across different scales of complexities and computational loads. In this paper, a method to perform relative (or local) terrain navigation using frame-to-frame features correspondences and altimeter measurements is presented. The proposed image-based approach relies on the implementation of the implicit extended Kalman filter, which works using nonlinear dynamic models and corrections from measurements that are implicit functions of the state variables. In particular, here, the epipolar constraint, which is a geometric relationship between the feature point position vectors and the camera translation vector, is employed as the implicit measurement fused with altimeter updates. In realistic applications, the image processing routines require a certain amount of time to be executed. For this reason, the presented navigation system entails a fast cycle using altimeter measurements and a slow cycle with image-based updates. Moreover, the intrinsic delay of the feature matching execution is taken into account using a modified extrapolation method
Regioselective Nucleophilic Additions to Diiron Carbonyl Complexes Containing a Bridging Aminocarbyne Ligand: A Synthetic, Crystallographic and DFT Study
Diiron ”-aminocarbyne compounds, 1aâe, are prepared in two steps from Fe2Cp2(CO)4, negating the need for difficult purification procedures of intermediate species; they are efficiently isolated by alumina chromatography. Minor amounts of ”-aminocarbyne aryl isocyanide compounds, 2aâc, are obtained as side products. The structures of the cations in 1a,c,e are calculated using DFT; the carbyne carbon is generally predicted to be the thermodynamic site of hydride addition, in agreement with a previous experimental finding concerning 1a. Accordingly, the reaction of 1e with NaBH4affords a bridging aminocarbene complex, 4, in 85 % yield. Otherwise, the reaction of 1c with NaBH4yields the aminocarbyneâcyclopentadiene derivative 3 (70 %), presumably as a consequence of the steric protection exerted by the xylylâmethyl groups towards the carbyne moiety. The sequential treatment of 1a,c with Li2CuCNMe2and MeSO3CF3affords 5a,b, comprising both aminocarbyne and alkoxycarbene ligands. In accordance with DFT calculations, the alkoxycarbene moiety in 5a is the most favourable site for nucleophilic attack. Thus, the reactions of 5a with NH2R (R = Et, iPr) and NBu4CN, respectively, give the aminocarbyne/aminocarbene complexes, 6a,b, and the aminocarbyne-α-cyanoalkyl 7. All the products are fully characterized by spectroscopic and analytical methods; moreover, the structures of 1a, 1d, 6a and 7 are elucidated by single-crystal X-ray diffraction studies
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Synthesis of functionalized iron N-heterocyclic carbene complexes and their potential application as flame behavior modifier in cross linked epoxy resins
The design of new flame retardants (FR) that avoid the use of halogen and phosphorus additives is challenging
and urgent. Herein we report on the synthesis of bis-amino functionalized N-heterocyclic carbene cyclopentadienone
iron complexes aimed at promoting the production of iron containing epoxy resins. Iron complexes
are successfully employed to obtain high Tg thermosets with as low as 5% hardener content. Moreover the
obtained resins display an impressive charring ability that paves the way to the application of such systems for
material with improved flame behavior
A generalised power-law formulation for the modelling of damping and stiffness nonlinearities
In this paper, a single-degree-of-freedom dynamic model is described, with displacement- and velocity-dependent nonlinearities represented by power laws. The model is intended to support the dynamic identification of structural components subjected to harmonic excitation. In comparison to other analytical expressions, the data-driven estimation of the nonlinear exponents provides a large versatility, making the generalised model adaptable for a wide number of different nonlinearities in both stiffness and damping. For instance, the proposed damping formulation can naturally accommodate air drag (quadratic) damping as well as dry friction. Differently to purely data-driven methods (e.g. black boxes), the obtained model is fully inspectable. The proposed formulation is here applied to the large oscillations of a prototype highly flexible wing and fitted on its steady state response in the frequency domain. These large-amplitude flap-wise bending oscillations are known to be affected by nonlinearities in both the stiffness (nonlinear hardening) and the velocity-dependent damping terms. The model is validated against experiments for different structural configurations and input amplitudes, as both these nonlinearities are energy-dependent
Identification of stably expressed reference small non-coding RNAs for microRNA quantification in high-grade serous ovarian carcinoma tissues
MicroRNAs (miRNAs) belong to a family of small nonâcoding RNAs (sncRNAs) playing important roles in human carcinogenesis. Multiple investigations reported miRNAs aberrantly expressed in several cancers, including highâgrade serous ovarian carcinoma (HGSâOvCa). Quantitative PCR is widely used in studies investigating miRNA expression and the identification of reliable endogenous controls is crucial for proper data normalization. In this study, we aimed to experimentally identify the most stable reference sncRNAs for normalization of miRNA qPCR expression data in HGSâOvCa. Eleven putative reference sncRNAs for normalization (U6, SNORD48, miRâ92aâ3p, letâ7aâ5p, SNORD61, SNORD72, SNORD68, miRâ103aâ3p, miRâ423â3p, miRâ191â5p, miRâ16â5p) were analysed on a total of 75 HGSâOvCa and 30 normal tissues, using a highly specific qPCR. Both the normal tissues considered to initiate HGSâOvCa malignant transformation, namely ovary and fallopian tube epithelia, were included in our study. Stability of candidate endogenous controls was evaluated using an equivalence test and validated by geNorm and NormFinder algorithms. Combining results from the three different statistical approaches, SNORD48 emerged as stably and equivalently expressed between malignant and normal tissues. Among malignant samples, considering groups based on residual tumour, miRâ191â5p was identified as the most equivalent sncRNA. On the basis of our results, we support the use of SNORD48 as best reference sncRNA for relative quantification in miRNA expression studies between HGSâOvCa and normal controls, including the first time both the normal tissues supposed to be HGSâOvCa progenitors. In addition, we recommend miRâ191â5p as best reference sncRNA in miRNA expression studies with prognostic intent on HGSâOvCa tissues
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