The Screen representation of spin networks: 2D recurrence, eigenvalue equation for 6j symbols, geometric interpretation and Hamiltonian dynamics

This paper treats 6j symbols or their orthonormal forms as a function of two variables spanning a square manifold which we call the "screen". We show that this approach gives important and interesting insight. This two dimensional perspective provides the most natural extension to exhibit the role of these discrete functions as matrix elements that appear at the very foundation of the modern theory of classical discrete orthogonal polynomials. Here we present 2D and 1D recursion relations that are useful for the direct computation of the orthonormal 6j, which we name U. We present a convention for the order of the arguments of the 6j that is based on their classical and Regge symmetries, and a detailed investigation of new geometrical aspects of the 6j symbols. Specifically we compare the geometric recursion analysis of Schulten and Gordon with the methods of this paper. The 1D recursion relation, written as a matrix diagonalization problem, permits an interpretation as a discrete Schr\"odinger-like equations and an asymptotic analysis illustrates semiclassical and classical limits in terms of Hamiltonian evolution.Comment: 14 pages,9 figures, presented at ICCSA 2013 13th International Conference on Computational Science and Applicatio

Improvement of sheep welfare and milk production fed on diet containing hydroponically germinating seeds.

Plasma cortisol and milk production responses of 45 lactating Comisana sheeps (4th- 5th parity), divided into three homogeneous groups of 15 subject each, were used to evaluate the effects of two different levels of partial substitution of a complete feed with hydroponically germinating seeds. Germinated oat was employed after 7 days of hydroponic growth. The three groups received the following diets: Control group (T) received only complete feed. The other 2 groups were fed on diet containing different levels of hydroponically germinating oat (1,5 kg – group A; 3 kg – group B). All the subjects have shown to accept the diets because the per capita ration was always completely consumed. In the second month, the A and B groups showed lower average values of cortisol (P<0.01) and a statistically significant increase in milk production as compared to T (P<0.05 and P<0.001). The obtained data induced to conclude that integration with hydroponically germinating oat in partial substitution of the complete feed does not modify biochemical and hematological parameters and seems to produce an improvement in animal welfare and production of milk

The screen representation of vector coupling coefficients or Wigner 3j symbols: exact computation and illustration of the asymptotic behavior

The Wigner $3j$ symbols of the quantum angular momentum theory are related to the vector coupling or Clebsch-Gordan coefficients and to the Hahn and dual Hahn polynomials of the discrete orthogonal hyperspherical family, of use in discretization approximations. We point out the important role of the Regge symmetries for defining the screen where images of the coefficients are projected, and for discussing their asymptotic properties and semiclassical behavior. Recursion relationships are formulated as eigenvalue equations, and exploited both for computational purposes and for physical interpretations.Comment: 14 pages, 8 figures, presented at ICCSA 2014, 14th International Conference on Computational Science and Application

Definition of a benchmark for low Reynolds number propeller aeroacoustics

Experimental and numerical results of a propeller of 0.3 m diameter operated at 5000 RPM and axial velocity ranging from 0 to 20 m/s and advance ratio ranging from 0 to 0.8 are presented as a preliminary step towards the definition of a benchmark configuration for low Reynolds number propeller aeroacoustics. The corresponding rotational tip Mach number is 0.23 and the Reynolds number based on the blade sectional chord and flow velocity varies from about 46000 to 106000 in the operational domain and in the 30% to 100% blade radial range. Force and noise measurements carried out in a low-speed semi-anechoic wind-tunnel are compared to scale-resolved CFD and low-fidelity numerical predictions. Results identify the experimental and numerical challenges of the benchmark and the relevance of fundamental research questions related to transition and other low Reynolds number effects

A Resilience and Robustness Oriented Design of Base-Isolated Structures: The New Camerino University Research Center

This paper analyses the new Research Centre designed for the University of Camerino and entirely financed by the national Civil Protection Department (DPC), following the seismic events in Central Italy in 2016. The building has been designed to guarantee speed of execution as well as a high level of safety, especially regarding seismic actions. The structural solution was to create an isolated system with a steel braced super-structure with pinned joints and r.c. sub-structures able to adapt to the complex morphology of the area. As described in the first part of the paper, design choices have been made to achieve a high level of resilience and robustness, i.e., to limit damage to structural and non-structural components and equipment under moderate and design seismic actions and to avoid disproportionate consequences in the event of extreme actions, larger than the design ones. In the second part of the paper, specific risk analyses have been carried out to evaluate the real performance of the building under increasing intensity levels, with reference to both serviceability and ultimate conditions. To this purpose a site-specific hazard study was first conducted, then non-linear analyses were performed using a hazard-consistent set of records with return periods ranging from TR = 60 years to TR = 10000 years. The main demand parameters of both the isolation system and the super-structure were recorded and capacity values corresponding to different ultimate and damage limit conditions were defined. The results obtained in terms of demand hazard curves show that the building performances in terms of robustness and resilience are very high, confirming the efficacy of the strategies adopted in the design

Towards the definition of a benchmark for low Reynolds number propeller aeroacoustics

Experimental and numerical results of a propeller of 0.3 m diameter operated in quiescent standard ambient conditions at 5000 RPM and axial velocity ranging from 0 to 20 m/s and advance ratio ranging from 0 to 0.8 are presented as a preliminary step towards the definition of a benchmark configuration for low Reynolds number propeller aeroacoustics. The corresponding rotational tip Mach number is 0.231 and the Reynolds number based on the blade sectional chord and flow velocity in the whole radial and operational domain ranges from about 54000 to 106000. Force and noise measurements carried out in a low-speed semi-anechoic windtunnel are compared with scale-resolved CFD and low-fidelity numerical results. Results identify the experimental and numerical challenges of the benchmark and the relevance of fundamental research questions related to transition and other low Reynolds number effects

Meat quality of Kuruma prawn (Marsupenaeus japonicus): preliminary evaluation

Among the peneids, Marsupenaeus japonicus, a cold-temperate species, carnivorous, is the mostly cultured prawn in Italy and in the Mediterranean Sea basin, thanks to the good adaptability to the temperature and salinity variations, to the good resistance to the manipulations (better resistance out of water), to its appreciate nourishing qualities and to the good growth rate (Lumare, 1998).Whereas the literature on cultured fish fillet is rich (Gjedrem, 1997; Lanari et al., 1999; Parisi et al., 2003), few are the information about the shrimp meat quality traits.Therefore, the present work aimed at typifying the variations of the meat quality characteristics in shrimps from semi-intensive (supplemented with an artificial diet) or extensive rearing systems