Characterisation of a hyperbranched polyesterin solution

The hyperbranched polyester based on poly dimethyl 5-(4 hydroxybutoxy) isophthalate ate has been successfully fractionated and a complete analysis of the solution properties has been carried out. Fractions with an average polydispersity of 1.8 over a range of molecular weight from 5x10(^3) g mol(^-1) were produced starting from an initial polymer with an approximate polydispersity of 7 and average molecular weight of l.3x10(^5) g mol(^-1). A linear analogue of the hyperbranched polyester has been also synthesised and different molecular weight samples were obtained by the use of a transesterification reaction. The hyperbranched fractions were investigated in the dilute regime by size exclusion chromatography, viscometry and light scattering techniques, while the semi-dilute regime has been studied by small-angle neutron scattering. Dilute solution properties in chloroform and in THF have been investigated, whilst D-THF was the solvent for the semi-dilute regime. In the dilute solution regime a whole range of physical parameters have been determined for the hyperbranched fractions and compared, where possible, with the linear analogues. From these results it is concluded that chloroform is a good solvent and THF a poor solvent for the hyperbranched polyester. The molar mass dependence of the radii of gyration has been interpreted by fractal dimension analysis and for the hyperbranched polyester the exponents obtained gave a fractal dimension d(_f)=2.5 ± 0.3 in both the solvents. The exponents obtained by the molar mass dependence of the radius of gyration in the semi-dilute regime have confirmed these values. These exponents also fit with those obtained from analysis of the intermediate g range of the small-angle neutron scattering cross sections, where an average slope 2.5 ± 0.1 was obtained. The values suggested the hyperbranched polymer is a mass fractal object with a rough surface

A Dual Hybrid Virtual Element Method for Plane Elasticity Problems

A dual hybrid Virtual Element scheme for plane linear elastic problems is presented and analysed. In particular, stability and convergence results have been established. The method, which is first order convergent, has been numerically tested on two benchmarks with closed form solution, and on a typical microelectromechanical system. The numerical outcomes have proved that the dual hybrid scheme represents a valid alternative to the more classical low-order displacement-based Virtual Element Method

Absorption and Scattering 2D Volcano Images from Numerically Calculated Space-weighting functions

Acknowledgments Yosuke Aoki and an anonymous reviewer greatly improved the quality of the paper. All calculations were made with Mathematica-10TM. Discussions with Marie Calvet, Danilo Galluzzo, Mario La Rocca, Salvatore De Lorenzo, Jessie Mayor and Ludovic Margerin are gratefully acknowledged. The authors are supported by MEDSUV European project and by Spanish Project Ephestos, CGL2011-29499-C02-01 and NOWAVES, TEC2015-68752. The TIDES EU travel Cost action provided travel money to support cooperation between Luca De Siena and the other authors.Peer reviewedPostprin

Transitions in auditory rehabilitation with bone conductive implant (bci)

Background: The bone conductive implants (BCI) are nowadays a reliable alternative for rehabilitation of specific forms of hearing loss, i.e. conductive, mixed or single sided deafness (SSD). Aims/Objective: To analyse the various factors in play when considering an auditory rehabilitation with a bone-conductive device (BCI). Materials and Methods: The clinical charts of subjects who underwent BCI application at the same Implanting Center from 2005 to 2018 were retrieved analysing also the reason for eventual explantation and the alternative option (transition) for hearing rehabilitation. Results: Nine BAHA Compact, 4 BAHA Intenso, 21 BAHA Divino, 3 BAHA BP100, 4 Ponto, 2 Sophono, 5 Bonebridge, 5 BAHA5 Attract; 11 BAHA5 Connect were used in 12 unilateral COM; 16 bilateral COM; 3 unilateral cholesteatoma; 6 bilateral cholesteatoma; 2 unilateral otosclerosis; 5 bilateral otosclerosis; 9 congenital malformations; 6 major otoneurosurgical procedures; 5 sudden deafness. Explantation was necessary for five subjects. Conclusions: Middle ear pathology and sequels from surgery represent the most common reason for BCI implantation, both in unilateral and in bilateral cases. Transition from one implantable device to another one can be predictable, mostly when explantation is necessary. Significance: The role of BCI for rehabilitation in middle ear pathology may be extremely important

Spectral shape-based assessment of SDOF nonlinear response to real, adjusted and artificial accelerograms

The simple study discussed in this paper compared different procedures to obtain sets of spectral matching accelerograms for nonlinear dynamic analysis of structures in terms of inelastic seismic response. Six classes of records were considered: original (unscaled) real records, real records moderately linearly scaled, real records significantly linearly scaled, real records adjusted by wavelets, and artificial accelerograms generated by two different procedures. The study is spectral shape-based; that is, all the considered sets of records, generated or selected, match individually (artificial and adjusted) or on average (real records) the same design spectrum for a case-study site in Italy. This is because spectral compatibility is the main criterion required for seismic input by international codes. Three kinds of single degree of freedom (SDOF) system, non-degrading and non-evolutionary, non-degrading and evolutionary, and both degrading and evolutionary, were used to evaluate the nonlinear response to the compared records. Demand spectra in term of peak and cyclic responses were derived for different strength reduction factors. Results of the analysis show that artificial or adjusted accelerograms may underestimate, in some cases, and at high nonlinearity levels, the displacement response, if compared to original real records, which are considered as a benchmark herein. However, this conclusion does not seem to be statistically significant. Conversely, if the cyclic response is considered, artificial record classes show a significant overestimation of the demand, which does not show up for wavelet-adjusted records. The two classes of linearly scaled records do not show systematic bias with respect to those unscaled for both types of response considered, which seems to confirm that amplitude scaling is a legitimate practice

Accuracy and precision of an intraoral scanner in complex prosthetic rehabilitations: an in vitro study

The main purpose of this study is to measure the accuracy and the precision of the intraoral optical scanner CS3500® (Carestream Dental LLC, Atlanta, USA) in complex clinical situations as full arch rehabilitations on impl ants. 50 scans of the acrylic resin model were performed by using CS3500® (Carestream Dental LLC, Atlanta, USA) scanner. Each scan was compared with the virtual model derived from scanning with the laboratory scanner Dscan3® (Enhanced Geometry Soluti on, Bologna, Italy) to measure a possible misalignment. The alignment error was found to be 79,6 ( ± 12,87)  m. The measurement was taken at the level of 2 distal scan - abutments. The scanner's precision ranges from 24 to 52  m , depending on the dist ance between scan - abutment. CS3500® (Carestream Dental LLC, Atlanta, USA) intraoral scanner has detected a valid device in the execution of complex rehabilitations on implants. His accuracy and precision values fall within the range established in li terature to define acceptable the prosthetic fitting on full arch implant rehabilitation

The 3D Attenuation Structure of Deception Island (Antarctica)

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Vibration Monitoring in the Compressed Domain with Energy-Efficient Sensor Networks

Structural Health Monitoring (SHM) is crucial for the development of safe infrastructures. Onboard vibration diagnostics implemented by means of smart embedded sensors is a suitable approach to achieve accurate prediction supported by low-cost systems. Networks of sensors can be installed in isolated infrastructures allowing periodic monitoring even in the absence of stable power sources and connections. To fulfill this goal, the present paper proposes an effective solution based on intelligent extreme edge nodes that can sense and compress vibration data onboard, and extract from it a reduced set of statistical descriptors that serve as input features for a machine learning classifier, hosted by a central aggregating unit. Accordingly, only a small batch of meaningful scalars needs to be outsourced in place of long time series, hence paving the way to a considerable decrement in terms of transmission time and energy expenditure. The proposed approach has been validated using a real-world SHM dataset for the task of damage identification from vibration signals. Results demonstrate that the proposed sensing scheme combining data compression and feature estimation at the sensor level can attain classification scores always above 94%, with a sensor life cycle extension up to 350x and 1510x if compared with compression-only and processing-free implementations, respectively