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Comparing CT colonography and flexible sigmoidoscopy: A randomised trial within a population-based screening programme
No full textPure and Fe-doped mesoporous titania catalyse the oxidation of acid orange 7 by H2O2 under different illumination conditions: Fe doping improves photocatalytic activity under simulated solar light
No full textA sample of mesoporous TiO2 (MT, specific surface area = 150 m2g1) and two samples of MT containing 2.5 wt.% Fe were prepared by either direct synthesis doping (Fe2.5-MTd) or impregnation (Fe2.5-MTi). Commercial TiO2 (Degussa P25, specific surface area = 56 m2g1) was used both as a benchmark and as a support for impregnation with either 0.8 or 2.5 wt.% Fe (Fe0.80-IT and Fe2.5-IT). The powders were characterized by X-ray diffraction, N2 isotherms at 196 C, Energy Dispersive X-ray (EDX) Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Diffuse Reflectance (DR) ultra-violet (UV)-Vis and Mössbauer spectroscopies. Degradation of Acid Orange 7 (AO7) by H2O2 was the test reaction: effects of dark-conditions versus both UV and simulated solar light irradiation were considered. In dark conditions, AO7 conversion was higher with MT than with Degussa P25, whereas Fe-containing samples were active in a (slow) Fenton-like reaction. Under UV light, MT was as active as Degussa P25, and Fe doping enhanced the photocatalytic activity of Fe2.5-MTd; Fe-impregnated samples were also active, likely due to the occurrence of a photo-Fenton process. Interestingly, the Fe2.5-MTd sample showed the best performance under solar light, confirming the positive effect of Fe doping by direct synthesis with respect to impregnation
Valutazione delle correlazioni tra parametri macchina di TBM-EPB e cedimenti indotti in superficie mediante l'uso di modelli a rete neurale
No full textThe aim of the work is to study the application of artificial neural network models to predict surface settlements and to define a hierarchy of TBM drive parameters in correlation with their effect on surface settlement with the scope to improve the advancement of the machine and for risk analysis/management purpose. In particular, a neural network model was created and trained to predict surface settlements giving as inputs the excavation parameters of the machine, the geometry and the geotechnical characteristics of the tunnel. Moreover, it was possible to investigate the correlations between input and output by means of three different methods proposed in literature. This method was applied to the case history of the stretch of Turin Metro (Line 1) from Porta Nuova to Lingotto station
A New Approach to Characterize Complex ICs in Terms of Scattering Parameters
No full textThe macro-models used in chip-level EMC analysis usually comprise equivalent circuits whose parameters are derived from the results of scattering parameter measurements. The constant increment of IC complexity along with the increment of the pin number has made this job difficult to accomplish, because of the numerous measurements to carry out and the propagation of related errors. Aiming to address this issue, this paper explores the possibility to obtain the scattering parameter matrix of an N-port system from measurements carried out with an m-port vector network analyzer, with the remaining N-m ports left open or loaded with a set of known impedances. According to the definition of scattering parameters, the measurement must be carried out with the ports loaded by their respective characteristic impedance (usually 50Ω ), which makes such measurements time-consuming, especially with devices featuring many ports. This is mostly because the N-m port not connected to the VNA must be matched during the measurement process. This paper presents a method that allows one to obtain the scattering matrix of an N-port device, using the S-par measurements carried out with the N-m ports not connected to the VNA, left open. The proposed technique requires ( ) set of measurements (Fig. 1), but there is no need to match with the reference impedances the port of DUT that are not connected to the VNA during the measurement process. To this purpose, three different methods suitable to derive the scattering parameters with the remaining N-m ports mismatched are available in literature. All these algorithms are based on two-step matrix transformation: the first step, starting from mismatched measured parameters, builds a set of partial matrices (S^p) containing the information related to the auxiliary load, while the second one reconstructs the true S parameter matrix from the partial matrices obtained in the first step. The great advantage of this approach is that the port not connected to the VNA can be left open. Unfortunately, this condition could be problematic because the parasitic elements loading the port not connected to the VNA, could affect the elements of the extracted matrix, especially at high frequency. The use of these techniques significantly reduces the number of steps needed to extract the final matrix. Aiming to check the proposed method, a three port IC was characterized using a 2-port VNA. At first, the scattering parameters resulting from the proposed procedure and those obtained using the definition of scattering parameters do not match in some frequency ranges. The mathematical analysis carried out afterwards pointed out that the observed errors deal with the conditioning number of the matrix to be inverted in the second step. Furthermore, the more the reflection coefficient magnitude of the auxiliary loads is close to one, the higher is the probability to obtain a high condition number, increasing the error of the reconstructed matrix. Therefore, in order to avoid the matrix inversion in ill conditioned point, the Newton's method was chosen as the optimal solution and its goodness was checked by repeating such a test on the above-mentioned circuit, as shown in Fig. 2
Textured insoles affect the plantar pressure distribution while elite rowers perform on an indoor rowing machine
No full textIntroduction: During rowing, foot positioning on the foot stretcher is critical to optimise muscle force transmission and boat propulsion. Following the beneficial effects of textured insoles on gait and balance, this study aims at investigating whether passive stimulation of foot mechanoreceptors induced by these insoles may contribute to improving foot loading pattern and symmetry during indoor rowing. Methods: Eleven elite rowers were assessed during controlled training on a standard rowing machine while wearing control, low-density or high-density textured insoles. Plantar pressure and knee and trunk kinematics were measured; performance data were recorded from the machine. Insole effect on kinematic parameters, peak and average values of foot force, contact area and position of centre of pressure was assessed with ANOVA and Bonferroni correction for pair-wise comparisons. Results: A main effect was observed for force and contact area, with the high-density insoles providing greatest values (P<0.035). No interaction was observed between side and insole (P>0.190), even though symmetry was higher with high-density insoles. Kinematics (P = 0.800) and rowing performance were not affected by insole type; a consistent though not statistically significant increase in mean travelled distance was observed for denser insoles (P>0.21). Conclusion: The high-density textured insoles affected foot loading distribution during indoor rowing. Rowers applied greater foot force and over a greater foot stretcher area with the high-density than the low-density and control insoles. These findings and the methodology applied may be relevant for the understanding and monitoring of rowing performance. © 2017 Vieira et al
Megaprotesi di ginocchio in pazienti affetti da neoplasie maligne del femore distale: studio delle alterazioni cinematiche e dei pattern di attivazione muscolare durante il cammino
No full textINTRODUZIONE I pazienti affetti da neoplasie maligne del femore distale possono oggi essere trattati salvando l'arto inferiore, mediante l'impianto di una protesi modulare vincolata di ginocchio [1][2]. Lo scopo di questo studio è stato la valutazione funzionale mediante analisi strumentale del cammino di pazienti portatori di megaprotesi di ginocchio, concentrandosi sulle asimmetrie presenti fra il lato protesico e quello controlaterale. METODI Sono stati coinvolti nello studio 24 pazienti con megaprotesi di ginocchio (età media: 40 ± 18 anni). Per eseguire l'analisi del cammino è stato utilizzato iI sistema di sensori indossabili STEP32, con la seguente configurazione: interruttori basografici, elettrogoniometri di ginocchio e sonde EMG posizionate su tibiale anteriore, gastrocnemio laterale, retto femorale, bicipite femorale, vasto mediale e laterale, bilateralmente. In particolare sono state valutate: 1) cinematica del ginocchio nel piano sagittale, 2) pattern di attivazione muscolare, del lato protesico e del controlaterale, durante una camminata a cadenza naturale della durata di due minuti e mezzo. RISULTATI La figura sottostante mostra l'angolo di flesso-estensione del ginocchio protesico e del controlaterale nella popolazione considerata (media ± deviazione standard). Si evidenzia una ridotta flessione di ginocchio del lato protesico rispetto al controlaterale durante la fase di accettazione del carico. Si sono inoltre evidenziate alterazioni dei pattern di attivazione muscolare nel lato protesico rispetto al controlaterale su tutti i muscoli analizzati. DISCUSSIONE L'analisi strumentale del cammino ha permesso di descrivere in modo quantitativo l'asimmetria del cammino dei pazienti portatori di megaprotesi di ginocchio, attraverso il confronto della cinematica del ginocchio e dei pattern di attivazione muscolare del lato protesico rispetto al controlaterale
Optimization Model of a Tandem Water Reservoir System Management
No full textThis paper presents a complex approach for modelling of a tandem reservoir systems for water drainage management. The model has been built over a segment of a river with a certain parameters of water inflow, water outflow, required power production and max possible flood occurrence. Then the segments may be replicated with specific parameters to simulate whole system of the river. The model has been optimized in order to obtain the water drainage operation policy with regards of current and expected water volumes in the reservoirs ratio, required power production revenue, and minimal flood occurrence. Model has been verified on a walk-through basis. The obtained results demonstrate good reliability disregards broad possible variations of the managed parameters and provide the optimal water drainage for minimum flood occurrence and desired power production revenue
Elastic, plastic, fracture analysis of masonry arches: A multi-span bridge case study
No full textIn this work a comparison is presented between elastic, plastic, and fracture analysis of the monumental arch bridge of Porta Napoli, Taranto (Italy). By means of a FEM model and applying the Mery's Method, the behavior of the curved structure under service loads is verified, while considering the Safe Theorem approach byHeyman, the ultimate carrying capacity of the structure is investigated. Moreover, by using Fracture Mechanics concepts, the damage process which takes place when the conditions assessed through linear elastic analysis are no longer valid, and before the set-in of the conditions established by means of the plastic limit analysis, is numerically analyzed. The study of these transitions returns an accurate and effective whole service life assessment of the Porta Napoli masonry arch bridge