Nonlinear vibration absorbers for ropeway roller batteries control

This work investigates a nonlinear passive control strategy designed to reduce the peak accelerations in ropeway roller batteries systems by deploying an array of nonlinearly visco-elastic vibration absorbers. The control effectiveness is compared with that of an equivalent array made of linearly visco-elastic absorbers. A nonlinear parametric model describing the interactions between the different parts of this mechanical multibody system previously developed by the present authors is here extended to include the passive vibration control system aimed to mitigate the acceleration peaks induced by the vehicles transit at different operational speeds. To this aim, a set of linearly visco-elastic vibration absorbers is first optimized through the Differential Evolution (DE) algorithm seeking to minimize the area below the frequency-response curves of the linear equations of motion. Then, a new group of nonlinearly visco-elastic absorbers, that can be largely tuned (i.e., they can exhibit either softening or hardening behaviors), is proposed to mitigate the accelerations induced in the roller by the vehicle transit. These nonlinearly visco-elastic absorbers are optimized by means of the DE algorithm and comparisons with the control achieved by the linear absorbers are carried out to show the higher performance of the proposed nonlinear device. A possible design of the nonlinearly visco-elastic absorber, based on the hysteresis of a wire rope assembly undergoing flexural cycles, is also proposed and discussed

Antiferromagnetic phase of the gapless semiconductor V3Al

Discovering new antiferromagnetic compounds is at the forefront of developing future spintronic devices without fringing magnetic fields. The antiferromagnetic gapless semiconducting D03 phase of V3Al was successfully synthesized via arc-melting and annealing. The antiferromagnetic properties were established through synchrotron measurements of the atom-specific magnetic moments, where the magnetic dichroism reveals large and oppositely-oriented moments on individual V atoms. Density functional theory calculations confirmed the stability of a type G antiferromagnetism involving only two-third of the V atoms, while the remaining V atoms are nonmagnetic. Magnetization, x-ray diffraction and transport measurements also support the antiferromagnetism. This archetypal gapless semiconductor may be considered as a cornerstone for future spintronic devices containing antiferromagnetic elements.Comment: Accepted to Physics Review B on 02/23/1

Weakly Coupled Motion of Individual Layers in Ferromagnetic Resonance

We demonstrate a layer- and time-resolved measurement of ferromagnetic resonance (FMR) in a Ni81Fe19 / Cu / Co93Zr7 trilayer structure. Time-resolved x-ray magnetic circular dichroism has been developed in transmission, with resonant field excitation at a FMR frequency of 2.3 GHz. Small-angle (to 0.2 degree), time-domain magnetization precession could be observed directly, and resolved to individual layers through elemental contrast at Ni, Fe, and Co edges. The phase sensitivity allowed direct measurement of relative phase lags in the precession oscillations of individual elements and layers. A weak ferromagnetic coupling, difficult to ascertain in conventional FMR measurements, is revealed in the phase and amplitude response of individual layers across resonance.Comment: 22 pages, 6 figures submitted to Physical Review

Nero Siciliano pig: effect of the diet on meat quality

In the context of a typical breeding system for the autochthonous pig races, the effects of the traditional diet (grain cereals, legumes and agro-industrial by-product) and of a commercial diet (pellets) on the meat quality of Nero Siciliano pig were studied. Thirty animals, 16 castrated males and 14 females, were divided into two groups of 15 each one homogeneous for live weight (32.47±1.74 kg), sex (8 males and 7 females) and age (2 months), called "Traditional" (TRA) and "Experimental" (EXPE). Pigs of "TRA" group were fed with barleycorn (2 kg/head/day) and citrus pulp (1 kg/head/day) whereas, those of "EXPE" group received 1.3 kg/head/day of a pelletted complete feed (Dry Matter: 87.5%, on a DM basis: 18.29% Crude Protein, 3.43% Ether Extract, 6.06% Crude Fiber, 7.43% Ash) formulated to be isoenergetic and isonitrogenous with the Traditional diet. The trial lasted 93 days, preceded by a 15day adaptation period. After the slaughter (FLW: EXPE 67.4kg vs. TRA 61.69 kg; P>0.05 and FCR: EXPE 3.71 kg/kg vs. TRA 6.65 kg/kg; P<0.001), chemical and fatty acid composition of the Longissimus lumborum muscle were determined as well as the acidic composition of the lard removed by the backfat. On the basis of the fatty acid profile, the quality indices were calculated. The oxidative stability (TBARs) of the intramuscular lipid was determined at 1, 3, 5 days after slaughtering. Data were subjected to ANOVA. Protein (EXPE 23.01 g/100g vs. TRA 23.17 g/100g) and lipid (EXPE 3.12 g/100g vs. TRA 2.69 g/100g) content of the muscle was unaffected by the diet whereas, moisture (EXPE 72.52 g/100g vs. TRA 73.072 g/100g) and ash (EXPE 1.01 g/100g vs. TRA 1.08 g/100g) levels showed significant (P<0.05) differences. As regards fatty acid composition of the meat, significant differences were observed for the total SFAs (EXPE 41.42% vs. TRA 38.95%, P<0.01) and PUFAs (EXPE 9.05% vs. TRA 12.11%, P<0.05) in particular for the n3 series (EXPE 0.79% vs. TRA 1.40%, P<0.05) and for the n6 series PUFAs (EXPE 8.11% vs. TRA 10.49%, P<0.05). Fatty acid composition of the lard showed significant (P<0.05) differences for MUFAs (EXPE 47.63% vs. TRA 49.11%) and PUFAs (EXPE 11.38% vs. TRA 10.01%); in particular significant differences for the n3 series (EXPE 0.77% vs. TRA 0.94%, P<0.05) and for the n6 series PUFAs (EXPE 10.62% vs. TRA 9.08%, P<0.01) were reported. The different distribution of the fatty acid classes in the meat and in the lard could be due to: i) the different acidic composition of the feeds (pellet vs. barleycorn + citrus pulp), ii) the different destinations of the plasmatic fatty acids during their metabolic cycle (constituents of adipose tissue, of tryglicerides, of membranes phospholipids). The quality indices have shown significant (P<0.001) differences only in the Longissimus lumborum muscle, with the highest values for the Atherogenic (EXPE 0.49% vs. TRA 0.42%,) and for the Thrombogenic indices (EXPE 1.11% vs. TRA 0.91%) in the EXPE group. No significant difference was observed for the oxidative stability of the muscle during the storage. Data show the importance to study specific diets for Nero Siciliano pig in relation to the destination of meat. Research supported by MIUR, PRIN-2003 ("Nero Siciliano pig breeding: evaluation of its production", Prof

A Classification of Countable Lower 1-transitive Linear Orders

This paper contains a classification of countable lower 1-transitive linear orders. This is the first step in the classification of countable 1-transitive trees given in Chicot and Truss (2009): the notion of lower 1-transitivity generalises that of 1-transitivity for linear orders, and it is essential for the structure theory of 1-transitive trees. The classification is given in terms of coding trees, which describe how a linear order is fabricated from simpler pieces using concatenations, lexicographic products and other kinds of construction. We define coding trees and show that a coding tree can be constructed from a lower 1-transitive linear order (X,≤) by examining all the invariant partitions on X. Then we show that a lower 1-transitive linear order can be recovered from a coding tree up to isomorphism

Wideband acoustic activation and detection of droplet vaporization events using a capacitive micromachined ultrasonic transducer

An ongoing challenge exists in understanding and optimizing the acoustic droplet vaporization (ADV) process to enhance contrast agent effectiveness for biomedical applications. Acoustic signatures from vaporization events can be identified and differentiated from microbubble or tissue signals based on their frequency content. The present study exploited the wide bandwidth of a 128-element capacitive micromachined ultrasonic transducer (CMUT) array for activation (8 MHz) and real-time imaging (1 MHz) of ADV events from droplets circulating in a tube. Compared to a commercial piezoelectric probe, the CMUT array provides a substantial increase of the contrast-to-noise ratio

Small bodies science with the Twinkle space telescope

© 2019 Society of PhotoOptical Instrumentation Engineers (SPIE). Twinkle is an upcoming 0.45-m space-based telescope equipped with a visible and two near-infrared spectrometers covering the spectral range 0.4 to 4.5 μm with a resolving power R 250 (λ 2.42 μm). We explore Twinkle's capabilities for small bodies science and find that, given Twinkle's sensitivity, pointing stability, and spectral range, the mission can observe a large number of small bodies. The sensitivity of Twinkle is calculated and compared to the flux from an object of a given visible magnitude. The number, and brightness, of asteroids and comets that enter Twinkle's field of regard is studied over three time periods of up to a decade. We find that, over a decade, several thousand asteroids enter Twinkle's field of regard with a brightness and nonsidereal rate that will allow Twinkle to characterize them at the instrumentation's native resolution with SNR > 100. Hundreds of comets can also be observed. Therefore, Twinkle offers researchers the opportunity to contribute significantly to the field of Solar System small bodies research

The Use of a Plant-Based Biostimulant Improves Plant Performances and Fruit Quality in Tomato Plants Grown at Elevated Temperatures.

Abiotic stresses can cause a substantial decline in fruit quality due to negative impacts on plant growth, physiology and reproduction. The objective of this study was to verify if the use of a biostimulant based on plant and yeast extracts, rich in amino acids and that contains microelements (boron, zinc and manganese) can ensure good crop yield and quality in tomato plants grown at elevated temperatures (up to 42 C). We investigated physiological responses of four di↵erent tomato landraces that were cultivated under plastic tunnel and treated with the biostimulant CycoFlow. The application of the biostimulant stimulated growth (plants up to 48.5% taller) and number of fruits (up to 105.3%). In plants treated with the biostimulant, antioxidants contents were higher compared to non-treated plants, both in leaves and in fruits. In particular, the content of ascorbic acid increased after treatments with CycoFlow. For almost all the traits studied, the e↵ect of the biostimulant depended on the genotype it was applied on. Altogether, the use of the biostimulant on tomato plants led to better plant performances at elevated temperatures, that could be attributed also to a stronger antioxidant defence system, and to a better fruit nutritional quality