6,134 research outputs found
Infinite impulse response modal filtering in visible adaptive optics
Diffraction limited resolution adaptive optics (AO) correction in visible
wavelengths requires a high performance control. In this paper we investigate
infinite impulse response filters that optimize the wavefront correction: we
tested these algorithms through full numerical simulations of a
single-conjugate AO system comprising an adaptive secondary mirror with 1127
actuators and a pyramid wavefront sensor (WFS). The actual practicability of
the algorithms depends on both robustness and knowledge of the real system:
errors in the system model may even worsen the performance. In particular we
checked the robustness of the algorithms in different conditions, proving that
the proposed method can reject both disturbance and calibration errors
About multi-resolution techniques for large eddy simulation of reactive multi-phase flows
A numerical technique for mesh refinement in the HeaRT (Heat Release and Transfer) numerical code is presented. In the CFD
framework, Large Eddy Simulation (LES) approach is gaining in importance as a tool for simulating turbulent combustion pro-
cesses, also if this approach has an high computational cost due to the complexity of the turbulent modeling and the high number of
grid points necessary to obtain a good numerical solution. In particular, when a numerical simulation of a big domain is performed
with a structured grid, the number of grid points can increase so much that the simulation becomes impossible: this problem can
be overcomed with a mesh refinement technique. Mesh refinement technique developed for HeaRT numerical code (a staggered
finite difference code) is based on an high order reconstruction of the variables at the grid interfaces by means of a least square
quasi-eno interpolation: numerical code is written in modern Fortran (2003 standard of newer) and is parallelized using domain
decomposition and message passing interface (MPI) standard
A critical analysis of happiness and well-being. Where we stand now, where we need to go
This paper aims to critically analyse happiness and well-being to find novel ways for theorizing and promoting better life conditions for individuals and societies. The necessity to shift from a subjective view of individual well-being to a more social and contextual version of these constructs is the common thread running throughout the whole work. To this end, the first part introduces the reader into the complexity of the happiness and well-being scholarship by outlining some of the most relevant approaches developed by the psychological and economic literature. After highlighting the limitations of both disciplines, the second part of the paper presents some alternative models, namely the Feminist Economics, the Capabilities Approach, and the model of Four Qualities of Life. In addition to these, we will draw attention, in the last section, to the Critical Community Psychology approach to happiness and well-being. Our main argument is that this emerging discipline bears the potential to frame the pursuit of the good life in a whole new fashion that takes into account a) contextual features, in particular the recourses that a given environment offers and the opportunity to access them, b) the role of power, justice, and liberation, and c) the value of participation, reciprocity, and ethics of care. Current limitations of CCP are also discussed and future directions outlined
From "Gomorrah Domain" to "Don Peppe Diana Lands". A Southern Italian Experience of Work-Based Liberation, Community Networking, and Well Being
The article describes working experiences in relation to empowering activities, which have been carried out in a local community in the province of Caserta (in Southern Italy), a place characterized by the widespread presence of organized criminal groups. In this study, workplace is intended as a community network aimed at the promotion of coscientization, liberation, and well-being. Specifically, this paper features initiatives and projects aimed at establishing new community values through a re-construction of a work-based social system standing against criminal clans, which tend to dominate not only economical transactions but also civil life
Seismic Analysis of Traditional Stone Rural Buildings: Case study of a one-storey building
Specific features of traditional rural buildings can influence the assessment of their seismic behaviour. When a change in intended use of traditional rural buildings is necessary, restoration work must comply with specific seismic norms and should preserve their original features. In this paper, a model for the seismic safety verification of masonry walls for inplane actions was applied to investigate the structural behaviour of one-storey stone-masonry traditional rural buildings, in relation to standards application and possible retrofitting interventions. The results showed that pier-panel collapse mechanisms and the simulation method of masonry spandrel behaviour are of importance and affect the need to provide for strengthening interventions
Enhancing heat treatment efficacy for insect pest control: A case study of a CFD application to improve the design and structure of a flour mill
Heat treatment of the indoor environment of flour mills is an alternative technique to chemical fumigation for controlling insect pests. The aim of this research was to assess temperature distribution inside a flour mill during a heat treatment for insect pest control by computational fluid dynamics (CFD) modelling and simulation. The model was validated by using the average values of experimental data acquired during a heat treatment carried out in a flour mill, which is representative of the building materials and techniques used in the milling industry of South Italy. Simulations were carried out in steady-state conditions, and simulated data were validated by the average values of air and wall temperature measurements. Since the modelled temperature distribution in the mill fit the real one with a good accuracy (maximum error equal to 2.57 °C), the CFD model was considered reliable to simulate other operating conditions. Since it was observed that the internal surface temperatures of the mill were much lower than the value required for the success of the heat treatment, equal to 45 °C, the CFD model could be used for improving the effectiveness of heat treatments in the flour mill. Application of the proposed CFD model in the simulation of specific interventions could be aimed at improving both building performance and fan heaters' localisatio,n in order to find the best configuration
Quasi-equilibrium lattice Boltzmann method
Abstract.: A general lattice Boltzmann method for simulation of fluids with tailored transport coefficients is presented. It is based on the recently introduced quasi-equilibrium kinetic models, and a general lattice Boltzmann implementation is developed. Lattice Boltzmann models for isothermal binary mixtures with a given Schmidt number, and for a weakly compressible flow with a given Prandtl number are derived and validate
Potential biogas production from agricultural by-products in Sicily. A case study of citrus pulp and olive pomace
Renewable energy sources represent a suitable alternative to conventional fossil fuels, due to the possible advantages in terms of environmental impact reduction. Anaerobic digestion of biomasses could be considered an environmental friendly way to treat and revalorise large amounts of by-products from farming industries because it ensures both pollution control and energy recovery. Therefore, the objective of this study was to define a methodology for evaluating the potential biogas production available from citrus pulp and olive pomace, which are suitable agricultural by-products for biogas production. In the first phase of the study, the spatial distribution of both olive and citrus-producing areas was analysed in Sicily, a geographical area of the Mediterranean basin highly representative of these types of cultivation. Then, a GIS-based model, which had been previously defined and utilised to evaluate the amount of citrus pulp and olive pomace production, was applied to this case study. Based on the results obtained for the different provinces of Sicily, the province of Catania was chosen as the study area of this work since it showed the highest production of both citrus pulp and olive pomace. Therefore, a further analysis regarded the quantification of olive pomace and citrus pulp at municipal level. The results of this analysis showed that the total amount of available citrus pulp and olive pomace corresponded theoretically to about 11,102,469 Nm3/year biogas. Finally, the methodology adopted in this study made it possible to identify suitable areas for the development of new biogas plants by considering both the spatial distribution of the olive and citrus growing areas and the locations of the existing processing industries
Observations of Isolated Neutron Stars with the ESO Multi-Conjugate Adaptive Optics Demonstrator
High-energy observations have unveiled peculiar classes of isolated neutron
stars which, at variance with radio pulsars, are mostly radio silent and not
powered by the star rotation. Among these objects are the magnetars,
hyper-magnetized neutron stars characterized by transient X-ray/gamma-ray
emission, and neutron stars with purely thermal, and in most cases stationary,
X-ray emission (a.k.a., X-ray dim isolated neutron stars or XDINSs). While
apparently dissimilar in their high-energy behavior and age, both magnetars and
XDINSs have similar periods and unusually high magnetic fields. This suggests a
tantalizing scenario where the former evolve into the latter.Discovering so far
uninvestigated similarities between the multi-wavelength properties of these
two classes would be a further step forward to establish an evolutionary
scenario. A most promising channels is the near infrared (NIR) one, where
magnetars are characterized by a distinctive spectral flattening with respect
to the extrapolation of the soft X-ray spectrum.We observed the two XDINSs RX
J0420.0-5022 and RX J1856.5-3754 with the Multi-Conjugate Adaptive Optics
Demonstrator (MAD) at the Very Large Telescope (VLT) as part of the instrument
guaranteed time observations program, to search for their NIR counterparts.
Both RX J1856.5-3754 and RX J0420.0-5022 were not detected down to K_s ~20 and
Ks ~21.5, respectively. In order to constrain the relation between XDINSs and
magnetars it would be of importance to perform deeper NIR observations. A good
candidate is 1RXS J214303.7+065419 which is the XDINS with the highest inferred
magnetic field.Comment: Accepted for publication in Astronomy and Astrophysic
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