4,854 research outputs found
The use of FRPs in seismic repair and retrofit: experimental verification
The application of FRPs in the seismic repair and retrofit of structures is addressed. The results from a few tests on full-scale structures, repaired and/or retrofitted with composites, performed at the ELSA laboratory are presented and discussed
Anyons, group theory and planar physics
Relativistic and nonrelativistic anyons are described in a unified formalism
by means of the coadjoint orbits of the symmetry groups in the free case as
well as when there is an interaction with a constant electromagnetic field. To
deal with interactions we introduce the extended Poincar\'e and Galilei Maxwell
groups.Comment: 22 pages, journal reference added, bibliography update
Discrete derivatives and symmetries of difference equations
We show on the example of the discrete heat equation that for any given
discrete derivative we can construct a nontrivial Leibniz rule suitable to find
the symmetries of discrete equations. In this way we obtain a symmetry Lie
algebra, defined in terms of shift operators, isomorphic to that of the
continuous heat equation.Comment: submitted to J.Phys. A 10 Latex page
SUSY approach to Pauli Hamiltonians with an axial symmetry
A two-dimensional Pauli Hamiltonian describing the interaction of a neutral
spin-1/2 particle with a magnetic field having axial and second order
symmetries, is considered. After separation of variables, the one-dimensional
matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum
mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and
also to the Hamiltonian hierarchies generated by intertwining operators. The
spectrum is studied by means of the associated matrix shape-invariance. The
relation between the intertwining operators and the second order symmetries is
established and the full set of ladder operators that complete the dynamical
algebra is constructed.Comment: 18 pages, 3 figure
q-Analogue of Shock Soliton Solution
By using Jackson's q-exponential function we introduce the generating
function, the recursive formulas and the second order q-differential equation
for the q-Hermite polynomials. This allows us to solve the q-heat equation in
terms of q-Kampe de Feriet polynomials with arbitrary N moving zeroes, and to
find operator solution for the Initial Value Problem for the q-heat equation.
By the q-analog of the Cole-Hopf transformation we construct the q-Burgers type
nonlinear heat equation with quadratic dispersion and the cubic nonlinearity.
In q -> 1 limit it reduces to the standard Burgers equation. Exact solutions
for the q-Burgers equation in the form of moving poles, singular and regular
q-shock soliton solutions are found.Comment: 13 pages, 5 figure
Mapping of Energy Community Development in Europe: State of the Art and Research Directions
Within the framework of defining a new energy paradigm to address climate change and other global challenges, the energy community model is gaining interest in several countries, especially in Europe. This article analyses the literature and experiences of organisational forms that fall under the definition of energy communities in a broad sense, in relation to their ability to bring improvements to the social, environmental and economic dimensions, and to ensure durability and replicability. The main elements that constitute a complete, albeit simplified, model of energy community are identified and analysed. The legislative and regulatory frameworks, technologies and social innovation frameworks, identified here as enabling elements, are discussed, as well as the elements of the energy community business models and the impacts generated at the environmental and energy, economic and social levels. The transformation potential of energy communities is confirmed as more than promising. However, in order to develop as a sustainable and replicable model capable of achieving social and environmental goals, as well as economic stability, further significant research and experimentation, following a cross-sectoral and multidisciplinary approach and strong political leadership, are needed
The potential role of biomethane for the decarbonization of transport: An analysis of 2030 scenarios in Italy
This paper aims at evaluating the best allocation of potential biomethane generation for the decarbonization of the transport system, presenting a case study in Italy. The country has some peculiar features, such as several operating biogas plants, additional potential feedstock for biogas/biomethane generation, a well-developed natural gas network and established relevant natural gas uses in different final sectors, including transport. Based on current estimates for sustainable biomethane potential by 2030, ranging from 2.3 to 7.6 billion cubic meters depending on the scenario, the analysis compares technologies for the generation, distribution and final use of biomethane. The results of the analysis confirm the potential interesting contribution of biomethane in decarbonizing the Italian transport system: a billion cubic meters of biomethane can lead to 2.33–4.37 MtCO2e savings, depending on the feedstock mix and the application. On a national basis, annual climate emission savings in 2030 range from 10.0 to 26.7 MtCO2e, depending on the scenario. Additional 3.1–8.1 MtCO2e of emissions can be avoided if the CO2 captured during the biomethane upgrading can be stored or reused. The proposed methodology could be used to extend the analysis to other countries, and to the European context
Rapid referral for headache management from emergency department to headache centre. four years data
Background: Headache is one of the most common reason for medical consultation to emergency department (ED). The inappropriate use of ED for non-emergency conditions is a problem in terms of overcrowding of emergency facilities, unnecessary testing and treatment, increased medical costs, burden on medical service providers and weaker relationships between patient and primary care provider. The aim of this study was to analyze the different stages of ED management of headache to identify those deficiencies that can be overcome by a fast referral to a headache clinic. Methods: The study is a retrospective analysis of the electronic medical records of patients discharged from an academic ED between January 1, 2015 and December 31, 2018 and referred to the tertiary level headache centre of the same hospital. We analyzed all aspects related to the permanence in ED and also assessed whether there was a match between the diagnosis made in ED and ours. Results: Among our sample of 244 patients, 76.2% were admitted as "green tag", 75% underwent a head computed tomography, 19.3% received a neurological consultation, 43% did not receive any pharmacological treatment and 62.7% still had headache at discharge. The length of stay in ED was associated with reporting the first aura ever (p = 0.014) and whether patients received consultations (p < 0.001). The concordance analysis shown a significant moderate agreement only for the diagnosis of migraine and only between triage and headache centre. Conclusions: Most patients who went to ED complaining of headache received the same treatment regardless of their diagnosis and in many cases the headache had not yet resolved at the time of discharge. Given the many shortcomings in headache management in ED, rapid referral to the headache centre is of paramount importance to help the patient achieve a definiteve diagnosis and appropriate treatment
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