The Medicina Station Status Report

General information about the Medicina Radio Astronomy Station, the 32-m antenna status, and the staff in charge of the VLBI observations is provided. In 2012, the data from geodetic VLBI observations were acquired using the Mark 5A recording system with good results. Updates of the hardware were performed and are briefly described

Magnetic Control of Transmission and Helicity of Nano-Structured Optical Beams in Magnetoplasmonic Vortex Lenses

We theoretically investigate the generation of far-field propagating optical beams with a desired orbital angular momentum by using an archetypical magnetoplasmonic tip surrounded by a gold spiral slit. The use of a magnetic material can lead to important implications once magneto-optical activity is activated through the application of an external magnetic field. The physical model and the numerical study presented here introduce the concept of magnetically tunable plasmonic vortex lens, namely a magnetoplasmonic vortex lens, which ensures a tunable selectivity in the polarization state of the generated nanostructured beam. The presented system provides a promising platform for a localized excitation of plasmonic vortices followed by their beaming in the far-field with an active modulation of both light's transmittance and helicity

Software per acquisizione segnali Total Power polarimetrici a larga banda

Il presente documento ha l’obiettivo di descrivere la struttura e le funzionalità del sistema realizzato al fine di eseguire l’acquisizione dei segnali Total Power all’interno del progetto di Distribuzione IF presso il ricevitore di SRT. Sono presentati dapprima i componenti hardware del sistema, basato sull’utilizzo del controller CRIO-9056 insieme ai moduli di acquisizione NI 9205 commercializzati dalla National Instruments. Successivamente viene illustrato il software che rende possibile l’acquisizione, progettato in ambiente LabVIEW

Software per acquisizione segnali Total Power polarimetrici a larga banda - Manuale Utente

Il presente documento ha l’obiettivo di descrivere le funzionalità del software Data Client, realizzato per permettere il controllo da parte dell’Utente del sistema di acquisizione dei segnali Total Power all’interno del progetto di Distribuzione IF presso il ricevitore di SRT. Il sistema si basa sull’utilizzo del controller CRIO-9056 insieme ai moduli di acquisizione NI 9205, commercializzati dalla National Instruments, e su software progettato in ambiente LabVIEW. Il software Data Client, eseguito sulla macchina server presente nel sistema, permette all’Utente di controllare l’esecuzione del software Real Time e quindi il processo di acquisizione svolto dalla scheda FPGA presente sui controller cRIO-9056. La programmazione del Data Client è avvenuta utilizzando il software LabVIEW Professional Development System for Windows

Morphology, thermal, mechanical properties and ageing of nylon 6,6/graphene nanofibers as Nano2 materials

Nylon 6,6 nanofibers loaded with different Graphene (G) amounts were successfully produced with stable process and good fiber quality, using an optimized solvent system suitable both for electrospinning and for G-suspension. G addition is found to significantly affect diameter but not thermal behaviour. A new phenomenological model is proposed for the interpretation of mechanical behaviour of nanofibrous mat, trying to take into account the nanofibrous morphology. The model highlights a G contribution to mechanical properties that mainly affects the initial steps of deformation where fibers stretch, slide, twist and re-orient. Finally, the nanofibers were analysed after 20 months ageing, showing no significant alteration with respect to the pristine ones, thus the lack of detrimental ageing-effects due to G addition

Water-Resistant Photo-Crosslinked PEO/PEGDA Electrospun Nanofibers for Application in Catalysis

Catalysts are used for producing the vast majority of chemical products. Usually, catalytic membranes are inorganic. However, when dealing with reactions conducted at low temperatures, such as in the production of fine chemicals, polymeric catalytic membranes are preferred due to a more competitive cost and easier tunability compared to inorganic ones. In the present work, nanofibrous mats made of poly(ethylene oxide), PEO, and poly(ethylene glycol) diacrylate, PEGDA, blends with the Au/Pd catalyst are proposed as catalytic membranes for water phase and low-temperature reactions. While PEO is a water-soluble polymer, its blending with PEGDA can be exploited to make the overall PEO/PEGDA blend nanofibers water-resistant upon photo-crosslinking. Thus, after the optimization of the blend solution (PEO molecular weight, PEO/PEGDA ratio, photoinitiator amount), electrospinning process, and UV irradiation time, the resulting nanofibrous mat is able to maintain the nanostructure in water. The addition of the Au-6/Pd-1 catalyst (supported on TiO2) in the PEO/PEGDA blend allows the production of a catalytic nanofibrous membrane. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), taken as a water phase model reaction, demonstrates the potential usage of PEO-based membranes in catalysis

Rubbery nanofibrous interleaves enhance fracture toughness and damping of CFRP laminates

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How Nanofibers Carry the Load: Toward a Universal and Reliable Approach for Tensile Testing of Polymeric Nanofibrous Membranes

Nanofibrous nonwovens show high versatility and outstanding properties, with reduced weight. Porous morphology, high material flexibility and deformability challenge their mechanical testing, severely affecting results reliability. Still today, a specific technical standard method to carry out tensile testing of nonwoven nanofibrous mats is lacking, as well as studies concerning tensile test data reliability. In this work, an accurate, systematic, and critical study is presented concerning tensile testing of nonwovens, using electrospun Nylon 66 random nanofibrous mats as a case study. Nanofibers diameter and specimen geometry are investigated to thoroughly describe the nanomat tensile behavior, also considering the polymer thermal properties, and the nanofibers crossings number as a function of the nanofibers diameter. Below a threshold value, which lies between 150 and 250 nm, the overall mat mechanical behavior changes from ductile to brittle, showing enhanced elastic modulus for a high number of nanofibers crossings. While specimen geometry does not affect tensile results. Stress–strain data are analyzed using a phenomenological data fitting model to better interpret the tensile behavior. The experimental results demonstrate the high reliability of the proposed mass-based load normalization, providing a simple, effective, and universally suitable method for obtaining high reproducible tensile stress–strain curves

DBESM P1 (primo prototipo) Matrice di commutazione

Validazione del prototipo di scheda DBESM: na matrice di commutazione funzionale all'instradamento dei ricevitori ai back-end del sistema osservativo SR

How Nanofibers Carry the Load: Toward a Universal and Reliable Approach for Tensile Testing of Polymeric Nanofibrous Membranes

Nanofibrous nonwovens show high versatility and outstanding properties, with reduced weight. Porous morphology, high material flexibility and deformability challenge their mechanical testing, severely affecting results reliability. Still today, a specific technical standard method to carry out tensile testing of nonwoven nanofibrous mats is lacking, as well as studies concerning tensile test data reliability. In this work, an accurate, systematic, and critical study is presented concerning tensile testing of nonwovens, using electrospun Nylon 66 random nanofibrous mats as a case study. Nanofibers diameter and specimen geometry are investigated to thoroughly describe the nanomat tensile behavior, also considering the polymer thermal properties, and the nanofibers crossings number as a function of the nanofibers diameter. Below a threshold value, which lies between 150 and 250 nm, the overall mat mechanical behavior changes from ductile to brittle, showing enhanced elastic modulus for a high number of nanofibers crossings. While specimen geometry does not affect tensile results. Stress\u2013strain data are analyzed using a phenomenological data fitting model to better interpret the tensile behavior. The experimental results demonstrate the high reliability of the proposed mass-based load normalization, providing a simple, effective, and universally suitable method for obtaining high reproducible tensile stress\u2013strain curves