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NANOINDENTATION BASED APPROACH FOR THE MECHANICAL CHARACTERIZATION OF POLYMERIC MICROSPHERES FOR DRUG DELIVERY
No full textPolymeric microspheres are largely studied for biomedical applications as, e.g., embolic agents to treat hyper-vascular tumors [1], or in tissue engineering [2]. The possibility to produce an ad hoc drug delivery system is the mostly studied characteristic of these type of microspheres. The class of polymeric microspheres used for biomedical applications are mainly composed by hydrophilic polymers, because of their biocompatibility. The polymers chosen for this study are Gelatin and Chitosan. Due to the instability of these two polymers in aqueous environment a natural cross-liker (genipin) is added. Here the mechanical properties of a new design of polymeric microspheres to be used as carriers for local release of drugs and grow factors, are investigated. The rationale of the study is understand how the used polymers and the presence of the cross-linker influence the mechanical properties of the microspheres and therefore the effectiveness in properly release drugs. Technically, nanoindentation was applied on microspheres of size in the range 20-70 µm. The mechanical characterization highlighted a viscous-elastic behavior of microspheres, with an increasing area of the characteristics hysteresis loops when the genipin concentration increases. Moreover, on measured load-displacement data, the Hertz model was applied to estimate the Young's Modulus. A protocol for the mechanical characterization of polymeric microspheres used for drug delivery will allow: (1) to support their design phase and (2) to improve their effectiveness in targeting the release of drugs
Effect of outdoor noise and façade sound insulation on indoor acoustic environment of Italian schools
No full textThe paper deals with the effect of outdoor noise mainly due to traffic and façade sound insulation on indoor noise level and speech intelligibility in classrooms. Results refer to the complete building stock of the Italian school buildings based on a census of the Italian Ministry of Education. The selected school sample consists of more than one hundred Italian schools of all levels (from nursery to upper secondary school) located in three Italian regions, built in different time periods and with different building techniques. The selected sample is representative of typical Italian schools. The façade sound insulation and the reverberation time of each school have been measured. The average outdoor noise level of about half the investigated schools has been measured and, for each school, the age of the building and the main characteristics of the façade have been listed (kind of glass, kind of ventilation, windows size, etc.). Based on these data, the correlations between both the main characteristics of the façades and the year of construction and the façade sound insulation have been investigated. Moreover, the influence of the noise coming from outdoor on the indoor noise level, speech intelligibility and speech to noise ratio have been analysed with reference to the situations both before and after the works carried out to improve the acoustic performances of façades. Results show that the indoor sound pressure level due to traffic noise is considerably reduced after the improvement of the façade acoustic insulation, while further treatments to indoor surfaces should be necessary to reduce internal reverberation time and to improve speech intelligibility
Further results on the development of a novel VTOL aircraft, the Anuloid. Part I: Aerodynamics
No full textThis paper presents the main outcomes of the preliminary development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid has three main features: lift is provided by a ducted fan powered by a turboshaft; control capabilities and anti-torque are due to a system of fixed and movable surfaces that are placed in the circular internal duct and the bottom portion of the aircraft; the Coanda effect is exploited to enable the control capabilities of such surfaces. In this paper, results from CFD analyses and wind tunnel tests are presented. Horizontal and vertical flights were considered, including accelerated flight. Particular attention was paid to the experimental analysis of the Coanda effect via a reduced scale 3D printed model. The results suggest that the Coanda effect is continuously present at the lower surface of the Anuloid and may be exploited for the control of the aircraft. Also, very complex 3D flows may develop around the aircraft
Characterization of fiber optic distributed temperature sensors for tissue laser ablation
No full textFiber optics is the most promising technology for distributed temperature sensing. The paper investigates the characterization of probes based on single or multiplexed fiber Bragg gratings, specifically conceived to evaluate the temperature distribution in applications that imply large temperature gradients, such as in laser induced thermal treatments of solid tumors. A setup for the characterization of fiber Bragg grating sensors in non uniform temperature conditions is described and examples of applications in case that mimic actual working conditions are reported
Interplay between Rashba interaction and electromagnetic field in the edge states of a two-dimensional topological insulator
No full textThe effects of Rashba interaction and electromagnetic field on the edge states of a two-dimensional topological insulator are investigated in a nonperturbative way. We show that the electron dynamics is equivalent to a problem of massless Dirac fermions propagating with an inhomogeneous velocity, enhanced by the Rashba profile with respect to the bare Fermi value vF . Despite the inelastic and time-reversal breaking processes induced by the electromagnetic field, no backscattering occurs without interaction. The photoexcited electron densities are explicitly obtained in terms of the electric field and the Rashba interaction, and are shown to fulfill generalized chiral anomaly equations. The case of a Gaussian electromagnetic pulse is analyzed in detail. When the photoexcitation occurs far from the Rashba region, the latter effectively acts as a "superluminal gate" boosting the photoexcited wave packet outside the light-cone determined by vF . In contrast, for an electric pulse overlapping the Rashba region, the emerging wave packets are squeezed in a manner that depends on the overlap area. The electron-electron interaction effects are also discussed, for both intraspin and interspin density-density coupling. The results suggest that Rashba interaction, often considered as an unwanted disorder effect, may be exploited to tailor the shape and the propagation time of photoexcited spin-polarized wave packets
Single mode-multimode-single mode optical fiber sensors: Review and application to temperature measurements using a bend-insensitive fiber
No full textThe paper reviews some aspects of optical fiber sensors based on a single mode-multimode-single mode structure first; then it presents the realization of a temperature sensor in which the multimode session is replaced with a bend-insensitive fiber working close to the two-propagating mode condition. Finally, it discusses some preliminary results obtained from the experimental characterization of the proposed sensor
Multi-physics analysis of a 1MW gyrotron cavity cooled by mini-channels
No full textThe interaction cavity of the European 170 GHz, 1 MW Continuous Wave (CW) gyrotron for ITER, whichcould also be water-cooled using mini-channels as recently proposed, experiences during operation avery large heat load (>15 MW/m2) localized on a very short (<1 cm) axial length. Such heat loads aretypical for high power gyrotrons.As the thermal deformation of the cavity influences the electromagnetic field structure and con-sequently the gyrotron operation, the analysis of the cavity performance requires the simultaneoussolution of the coupled thermal-hydraulic, thermo-mechanic and electro-magnetic fields. In this paper,the thermal behaviour of the cavity under nominal heat load is computed first by CFD. Then a 3Dthermo-mechanical model of the cavity is developed, based on the temperature maps computed byCFD, to evaluate the resulting deformation of the inner cavity surface. Finally the deformation is usedto compute the updated heat load coming from the electromagnetic field generated by the electronbeam in the deformed cavity, which becomes the input for a new iteration of the thermal-hydraulic,thermal-mechanical and electromagnetic analyses. It is shown that this iterative procedure converges toa self-consistent heat-load/temperature-field/deformation-field picture in nominal operating conditions,without exceeding a temperature of ∼230◦C on the inner surface of the cavity
Soft Cooperation and Rural Development in Aso Valley in Italy
No full textAso Valley is among the most advanced agricultural contexts in Italy. In recent years it has hosted the experimentation of some policy tools whose innovation was given by the fruitful cooperation between public and private actors in promoting rural development. This paper aims at critically analyzing contents and aims of the spaces of cooperation in Aso Valley, demonstrating to which extent they have influenced policy-making processes and reconstructed the fragmented institutional panorama characterizing the local level. Emphasis is placed on the role that planning could play in supporting rural policies. It is demonstrated that the integration of rural policies into territorial planning could better sustain local farmers' activity, empower agricultural enterprises and reduce the conflicts between urban and rural land uses