Turbofan forced mixer-nozzle internal flowfield. Volume 2: Computational fluid dynamic predictions

A general program was conducted to develop and assess a computational method for predicting the flow properties in a turbofan forced mixed duct. The detail assessment of the resulting computer code is presented. It was found that the code provided excellent predictions of the kinematics of the mixing process throughout the entire length of the mixer nozzle. The thermal mixing process between the hot core and cold fan flows was found to be well represented in the low speed portion of the flowfield

Modelling ionised and photodissociated regions

The bulk of the mass in star-forming environments is contained in photodissociated regions (PDRs) where the chemistry is controlled by the far ultraviolet radiation field coming from nearby ionizing sources. H II regions can be found throughout active star forming galaxies as they are also controlled by the presence of a nearby ionizing source. In fact, H II regions, PDRs, and molecular clouds are not distinct physical regions, but rather a series of layers that are unified by the transport of radiation from hot stars into cold gas and the flow of cold molecular gas into hot ionized regions. The relative contributions of the ultraviolet radiation field from different gas phases can be estimated from observations of several far infrared forbidden lines such as [C II]158\mum, [O I]145\mum and 63\mum. Fine structure emission line studies provide valuable information on H II and PDR regions and it is well known that they originate in the outer part of both H II and PDR regions. The only exception are the nitrogen lines that clearly come exclusively from ionized regions. With the launch of ISO the far infrared properties of galaxies were observed with greater sensitivity than ever before. This thesis deals with the study of [C II]158\mum, [O I]145\mum, 63\mum and partly CO in external galaxies. In Chapter 3 we investigate the [C II]158\mum, [O I]145\mum and 63\mum emission lines in a sample of external galaxies in order to use them as diagnostics to infer the physical conditions in the gas, such as temperatures, densities and radiation fields. This study was carried out using the photodissociation UCL PDR code, testing PDR model results against ISO LWS observations. In addition, a detailed study of the oxygen self absorption, computed by modelling the emission line profiles with the radiative transfer SMMOL code, was conducted. In Chapter 4 a detailed study of the starburst NGC 4038 has been performed by using both MOCASSIN and UCL PDR. The contribution of [C II] 158\mum, [O I] 63\mum and 145\mum lines coming from the H II region was studied using the 3D ionization MOCASSIN code. We then used the computed radiation field at the ionization front as an input for the photodissociation UCL PDR code and an examination of the oxygen self absorption and a comparison of the CO rotational emission lines with CSO observations, were also presented. Finally, to improve the interpretation of future observations such as those from ALMA and HERSCHEL, a feasibility test on the coupling of the two codes (MOCASSIN and UCL PDR) was performed and the results are presented in Chapter 5. Conclusion and ideas for future work are presented in Chapter 6

From Hilferding to Hilferding? Finance-capital in Italian capitalism, 1913-2010

This paper analyses the Italian corporate network from 1913 to 2010 by using the interlocking directorates technique and focusing on eight benchmark years (1913, 1927, 1936, 1960, 1972, 1983, 2001, and 2010). For each benchmark year, the top 250 companies (50 financial and 200 non financial companies) by total assets have been selected. For each benchmark year, after showing a descriptive statistics of the companies and the directors included in the sample, the paper develops a network connectivity analysis of the system. This is integrated by a historical and structural analysis. The paper reveals some distinct phases in the long term evolution of the Italian corporate network, consequent on some major institutional break-ups (the crisis of the German-type universal banks and the creation of large state-owned sector of the economy in the early 1930s; the nationalisation of the electricity industry in 1962; a massive privatisation of state-owned enterprises and a reform of the banking system in the 1990s) and the emergence of the technological trajectory of the third industrial revolution in the 1970s. In particular, the paper shows that one major consequence of the privatizations and of the reform of the banking system in the 1990s was a return of banks in a central position in the network from which they had disappeared after the collapse of the universal banks in the 1930s

The Italian Corporate Network, 1913-2001

This paper analyses the Italian corporate network from 1913 to 2001 by using the interlocking directorates technique and focusing on seven benchmark years (1913, 1927, 1936, 1960, 1972, 1983, and 2001). For each benchmark year, the top 250 companies (50 financial and 200 non financial companies) by total assets have been selected. For each benchmark year, After showing a descriptive statistics of the companies and the directors included in the sample, the paper develops a network connectivity analysis of the system. This is integrated by a historical and structural analysis. The paper reveals some distinct phases in the long term evolution of the Italian corporate network, consequent on some major institutional break-ups (the crisis of the German-type universal banks and the creation of large state-owned sector of the economy in the early 1930s; the nationalisation of the electricity industry in 1962; a massive privatisation of state-owned enterprises in the 1990s) and the emergence of the technological trajectory of the third industrial revolution in the 1970s

SiO collimated outflows driven by high-mass YSOs in G24.78+0.08

We imaged the molecular outflows towards the cluster of high-mass young stellar objects G24.78+0.08 at high-angular resolution using SiO emission, which is considered the classical tracer of protostellar jets. We performed SiO observations with the VLA interferometer in the J = 1-0 v=0 transition and with the SMA array in the 5-4 transition. A complementary IRAM 30-m single-dish survey in the (2-1), (3-2), (5-4), and (6-5) SiO lines was also carried out. Two collimated SiO high-velocity outflows driven by the A2 and C millimeter continuum massive cores have been imaged. On the other hand, we detected no SiO outflow driven by the young stellar objects in more evolved evolutionary phases that are associated with ultracompact (B) or hypercompact (A1) HII regions. The LVG analysis reveals high-density gas (10^3-10^4 cm-3), with well constrained SiO column densities (0.5-1 10^15 cm-2). The driving source of the A2 outflow is associated with typical hot core tracers such as methyl formate, vinyl cyanide, cyanoacetilene, and acetone. The driving source of the main SiO outflow in G24 has an estimated luminosity of a few 10^4 Lsun (typical of a late O-type star) and is embedded in the 1.3 mm continuum core A2, which in turn is located at the centre of a hot core that rotates on a plane perpendicular to the outflow main axis. The present SiO images support a scenario similar to the low-mass case for massive star formation, where jets that are clearly traced by SiO emission, create outflows of swept-up ambient gas usually traced by CO.Comment: Astronomy & Astrophysics, in pres

Statistical characterization of the anisotropic strain energy in soft materials with distributed fibers

We discuss analytical and numerical tools for the statistical characterization of the anisotropic strain energy density of soft hyperelastic materials embedded with fibers. We consider spatially distributed orientations of fibers following a tridimensional or a planar architecture. We restrict our analysis to material models dependent on the fourth pseudo-invariant I4 of the Cauchy-Green tensor, and to exponential forms of the fiber strain energy function Ψaniso. Under different loading conditions, we derive the closed-form expression of the probability density function for I4 and Ψaniso. In view of bypassing the cumbersome extension-contraction switch, commonly adopted for shutting down the contribution of contracted fibers in models based on generalized structure tensors, for significant loading conditions we identify analytically the support of the fibers in pure extension. For uniaxial loadings, the availability of the probability distribution function and the knowledge of the support of the fibers in extension yield to the analytical expression of average and variance of I4 and Ψaniso, and to the direct definition of the average second Piola-Kirchhoff stress tensor. For generalized loadings, the dependence of I4 on the spatial orientation of the fibers can be analyzed through angle plane diagrams. Angle plane diagrams facilitate the assessment of the influence of the pure extension condition on the definition of the stable support of fibers for the statistics related to the anisotropic strain energy density. © 2015 Elsevier Ltd. All rights reserved

Inequality in Pre-Industrial Europe (1260–1850): New Evidence From the Labor Share

The dynamics of economic inequality and its relationship with economic growth in the preindustrial world is increasingly attracting the attention of both economists and economic historians. In this paper, we tackle this theme by introducing new estimates of the labor share in five major European countries (England, France, Holland, Spain, and Portugal) for the period 1250–1850. Our estimates are constructed using an innovative method based on the conversion of real wages in 2011 PPP $. Overall, we find a complex pattern of evolution of the labor share with major fluctuations. Furthermore, using the inequality possibility frontier (IPF) framework, our results suggest that preindustrial Europe was characterized by a negative relationship between the extraction ratio and GDP

The origins of the Italian regional divide: Evidence from real wages, 1861-1913

The origins of the Italian North-South divide have always been controversial. We fill this gap by estimating a new dataset of real wages (Allen 2001; Allen et al. 2011) from Unification (1861) to WWI. Italy was very poor throughout the period, with a modest improvement since the late nineteenth century. This improvement started in the Northwest industrializing regions, while real wages in other macro-areas remained stagnant. The gap Northwest/South widened until the end of the period. Focusing on the drivers of regional trends, we find that human capital formation exerted strong positive effect on the growth of real wages

Classification of Sensory Neural Signals through Deep Learning Methods

The recording and analysis of peripheral neural signals can be beneficial to provide feedback to prosthetic limbs and recover the sensory functionality in people with nerve injuries. Nevertheless, the interpretation of sensory recordings extracted from the nerve is not trivial, and only few studies have applied classifiers on sequences of neural signals without previous feature extraction. This paper evaluates the classification performance of two deep learning (DL) models (CNN and ConvLSTM) applied to the electroneurographic (ENG) activity recorded from the sciatic nerve of rats. The ENG signals, available from two public datasets, were recorded using multi-channel cuff electrodes in response to four sensory inputs (plantarflexion, dorsiflexion, nociception, and touch) elicited in response to mechanical stimulation applied to the hind paw of the rats. Different temporal lengths of the signals were considered (2.5 s, 1 s, 500 ms, 200 ms, and 100 ms), Both the two DL models proved to correctly discriminate sensory stimuli without the need of hand-engineering feature extraction. Moreover, ConvLSTM outperformed state-of-the-art results in classifying sensory ENG activity (more than 90% F1-score for sequences greater than 500 ms), and it showed promising results for real-time application scenarios

A numerical model of the human cornea accounting for the fiber-distributed collagen microstructure

We present a fiber-distributed model of the reinforcing collagen of the human cornea. The model describes the basic connections between the components of the tissue by defining an elementary block (cell) and upscaling it to the physical size of the cornea. The cell is defined by two sets of collagen fibrils running in approximately orthogonal directions, characterized by a random distribution of the spatial orientation and connected by chemical bonds of two kinds. The bonds of the first kind describe the lamellar crosslinks, forming the ribbon-like lamellae; while the bonds of the second kind describe the stacking crosslinks, piling up the lamellae to form the structure of the stroma. The spatial replication of the cell produces a truss structure with a considerable number of degrees of freedom. The statistical characterization of the collagen fibrils leads to a mechanical model that reacts to the action of the deterministic intraocular pressure with a stochastic distribution of the displacements, here characterized by their mean value and variance. The strategy to address the solution of the heavy resulting numerical problem is to use the so-called stochastic finite element improved perturbation method combined with a fully explicit solver. Results demonstrate that the variability of the mechanical properties affects in a non-negligible manner the expected response of the structure to the physiological action