analysis of dynamic instabilities in bridges under wind action through a simple friction based mechanical model

Abstract In the field of stability of structures under nonconservative loads, the concept of follower force has long been debated by scientists due to the lack of actual experimental evidence. Bigoni and Noselli's work [2] aimed to investigate flutter and divergence instability phenomena through a purely mechanical model with Coulomb friction represents a praiseworthy attempt to shed light on this issue. A two-degree-of-freedom (DOF) system, conceived as a variant of the Ziegler column, was set up experimentally. The follower load was induced by a frictional force acting on a wheel mounted at the column end, so that the rolling friction vanishes and the sliding frictional force keeps always coaxial to the column, thus representing a tangential follower force. Along this research line, in this contribution a model is elaborated that stems from the analysis of an elastically supported rigid plate that represents the behaviour of a bridge deck suspended on springs and subjected to a wind-induced force. The wind force has been simulated by a Coulomb friction force acting on a wheel mounted on the plate aerodynamic centre, so that the sliding friction force keeps perpendicular to the plate axis throughout the system motion, thus representing a follower force. To properly reproduce the wind force, the friction force is applied to the wheel by a lever mechanism wherein one of the two lever arms involves the plate rotation via a particular circular guide. The corresponding equations of motion of the bridge deck are derived in a completely dimensionless form. Depending on the mechanical characteristics of the plate and the magnitude of the friction force, stability, flutter or divergence phenomena may occur. The occurrence of these phenomena is numerically investigated by integration of the equations of motion. The development of an experimental framework of the model to corroborate these intuitions is the object of an ongoing research

First results of the European grapevine collections' collaborative network: Validation of a standard eno-carpological phenotyping method

Rustioni, L. et al.A standard protocol for phenotyping structural and compositional aspects of the grape berry has been adopted by 18 East and West European germplasm collections during one season by testing a total of 469 accessions, including reference cultivars as well as local and minor germplasm accessions of specific interest. The protocol consists in the collection of triplicates for 26 phenotypic traits, from biological samples, each formed by 10 berries collected from 9 representative bunches from every analyzed accessions. The protocol concatenates the data from measurements and acquisitions, with the objective to generate new derived variables, which are expressed with different units (%; content per kg of grapes, per berry, per g of tissue). For each variable, the Least Significant Differences (LSD), to contrast a pair of single accession mean values, and the Confidence Intervals (CI), to estimate each single accession mean value, were computed. The application of the protocol revealed satisfactory results with high accuracy and efficiency in estimation of phenotypic traits of each accession. The whole data set will be useful for researchers, breeders and viticulturists in yield evaluation of grapevine cultivars, as well as in comparative analyses of environment-variety interaction.Joint publication of the COST Action FA1003 “East-West Collaboration for Grapevine Diversity Exploration and Mobilization of Adaptive Traits for Breeding”.Peer Reviewe

Assessment of energy return on energy investment (EROEI) of oil bearing crops for renewable fuel production

As reported in literature the production of biodiesel should lead to a lower energy consumption than those obtainable with its use. So, to justify its consumption, a sustainable and “low input” production should be carried out. In order to assess the sustainability of Linum usitatissimum, Camelina sativa and Brassica carinata cultivation for biodiesel production in terms of energy used compared to that obtained, the index EROEI (Energy Return On Energy Invested) has been used. At this aim, an experimental field was realised in the south-eastern Sicilian land. During the autumn-winter crop cycle, no irrigation was carried out and some suitable agricultural practices have been carried out taking into account the peculiarity of each type of used seeds. The total energy consumed for the cultivation of oil bearing crops from sowing to the production of biodiesel represents the Input of the process. In particular, this concerned the energy embodied in machinery and tools utilized, in seed, chemical fertilizer and herbicide but also the energy embodied in diesel fuels and lubricant oils. In addition, the energy consumption relating to machines and reagents required for the processes of extraction and transesterification of the vegetable oil into biodiesel have been calculated for each crops. The energy obtainable from biodiesel production, taking into account the energy used for seed pressing and for vegetable oil transesterification into biodiesel, represents the Output of the process. The ratio Output/Input gets the EROEI index which in the case of Camelina sativa and Linum usatissimum is greater than one. These results show that the cultivation of these crops for biofuels production is convenient in terms of energy return on energy investment. The EROEI index for Brassica carinata is lower than one. This could means that some factors, concerning mechanisation and climati

Evaluation of eno-carpological traits in Georgian grapevine varieties from Skra germplasm repository

Eno-carpological traits were evaluated in twenty one colored and fifteen white Georgian autochthonous grapevine varieties grown in the Skra Germplasm Repository, during two years (2012 and 2013). Mostly of the studied accessions were minor varieties originated from various Georgian provinces. The spectrophotometric method proposed in the framework of the COST action FA1003 has been adopted for total anthocyanin and polyphenol analyses in skin and seed extracts. The obtained results showed that the content of phenolic compounds as well as other eno-carpological parameters varies greatly according to the variety. In general, the total phenol contents ranged from 546.7 to 2818.4 mg∙kg-1 of grape, and anthocyanins varied from 49.5 to 2826.6 mg∙kg-1 of grape. The highest content of total phenolics and total anthocyanins was found in the variety 'Saperavi Budeshuriseburi'

Near-infrared reflectance spectroscopy for predicting the phospholipid fraction and the total fatty acid composition of freeze-dried beef

Peer reviewe

Near-infrared reflectance spectroscopy for predicting the phospholipid fraction and the total fatty acid composition of freeze-dried beef

Research on fatty acids (FA) is important because their intake is related to human health. NIRS can be a useful tool to estimate the FA of beef but due to the high moisture and the high absorbance of water makes it difficult to calibrate the analyses. This work evaluated near-infrared reflectance spectroscopy as a tool to assess the total fatty acid composition and the phospholipid fraction of fatty acids of beef using freeze-dried meat. An average of 22 unrelated pure breed young bulls from 15 European breeds were reared on a common concentrate-based diet. A total of 332 longissimus thoracis steaks were analysed for fatty acid composition and a freeze-dried sample was subjected to near-infrared spectral analysis. 220 samples (67%) were used as a calibration set with the remaining 110 (33%) being used for validation of the models obtained. There was a large variation in the total FA concentration across the animals giving a good data set for the analysis and whilst the coefficient of variation was nearly 68% for the monounsaturated FA it was only 27% for the polyunsaturated fatty acids (PUFA). PLS method was used to develop the prediction models. The models for the phospholipid fraction had a low R2 p and high standard error, while models for neutral lipid had the best performance, in general. It was not possible to obtain a good prediction of many individual PUFA concentrations being present at low concentrations and less variable than other FA. The best models were developed for Total FA, saturated FA, 9c18:1 and 16:1 with R2 p greater than 0.76. This study indicates that NIRS is a feasible and useful tool for screening purposes and it has the potential to predict most of the FA of freeze-dried beef. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Polymerogenic neuroserpin causes mitochondrial alterations and activates NFκB but not the UPR in a neuronal model of neurodegeneration FENIB

The neurodegenerative condition FENIB (familiar encephalopathy with neuroserpin inclusion bodies) is caused by heterozygous expression of polymerogenic mutant neuroserpin (NS), with polymer deposition within the endoplasmic reticulum (ER) of neurons. We generated transgenic neural progenitor cells (NPCs) from mouse fetal cerebral cortex stably expressing either the control protein GFP or human wild type, polymerogenic G392E or truncated (delta) NS. This cellular model makes it possible to study the toxicity of polymerogenic NS in the appropriated cell type by in vitro differentiation to neurons. Our previous work showed that expression of G392E NS in differentiated NPCs induced an adaptive response through the upregulation of several genes involved in the defence against oxidative stress, and that pharmacological reduction of the antioxidant defences by drug treatments rendered G392E NS neurons more susceptible to apoptosis than control neurons. In this study, we assessed mitochondrial distribution and found a higher percentage of perinuclear localisation in G392E NS neurons, particularly in those containing polymers, a phenotype that was enhanced by glutathione chelation and rescued by antioxidant molecules. Mitochondrial membrane potential and contact sites between mitochondria and the ER were reduced in neurons expressing the G392E mutation. These alterations were associated with a pattern of ER stress that involved the ER overload response but not the unfolded protein response. Our results suggest that intracellular accumulation of NS polymers affects the interaction between the ER and mitochondria, causing mitochondrial alterations that contribute to the neuronal degeneration seen in FENIB patients

Rayleigh Imaging of Graphene and Graphene Layers

We investigate graphene and graphene layers on different substrates by monochromatic and white-light confocal Rayleigh scattering microscopy. The image contrast depends sensitively on the dielectric properties of the sample as well as the substrate geometry and can be described quantitatively using the complex refractive index of bulk graphite. For few layers (<6) the monochromatic contrast increases linearly with thickness: the samples behave as a superposition of single sheets which act as independent two dimensional electron gases. Thus, Rayleigh imaging is a general, simple and quick tool to identify graphene layers, that is readily combined with Raman scattering, which provides structural identification.Comment: 8 pages, 9 figure

Left gaze bias in humans, rhesus monkeys and domestic dogs

While viewing faces, human adults often demonstrate a natural gaze bias towards the left visual field, that is, the right side of the viewee’s face is often inspected first and for longer periods. Using a preferential looking paradigm, we demonstrate that this bias is neither uniquely human nor limited to primates, and provide evidence to help elucidate its biological function within a broader social cognitive framework. We observed that 6-month-old infants showed a wider tendency for left gaze preference towards objects and faces of different species and orientation, while in adults the bias appears only towards upright human faces. Rhesus monkeys showed a left gaze bias towards upright human and monkey faces, but not towards inverted faces. Domestic dogs, however, only demonstrated a left gaze bias towards human faces, but not towards monkey or dog faces, nor to inanimate object images. Our findings suggest that face- and species-sensitive gaze asymmetry is more widespread in the animal kingdom than previously recognised, is not constrained by attentional or scanning bias, and could be shaped by experience to develop adaptive behavioural significance