2,521 research outputs found
Infrared Screening of Residential Buildings for Energy Audit Purposes: Results of a Field Test
Abstract: In the European Union (EU), the building sector is responsible for approximately 40% of total energy consumption. The existing building stock is inefficient and can, and indeed must be retrofitted to address this issue. The practical implementation
of the European strategies requires knowledge of the energy performance of existing buildings through energy audit techniques. Application of thermography in the fields of energy are very widespread, since, through such a non-invasive investigation, and through correct interpretation of infrared images, it is possible to highlight inefficiencies in buildings and related facilities. The paper shows and discusses the results of an infrared audit campaign on 14 existing buildings located in Milan Province (Italy) made in different construction periods and characterised, therefore, by different building technologies.
The U-values obtained in an indirect way through the thermography of the opaque walls of the buildings investigated, were compared with the actual known values in order to verify
the reliability of the method and the possible margin of error. The study indicated that the category of buildings in which the application of this method is sufficiently reliable is that of
solid-mass structure buildings, the most widespread in Italy, whereas in the case of buildings whose external walls are insulated, the percentage of deviation is very high
On Operational Earthquake Forecast and Prediction Problems.
In his SSA presidential address (Jordan, 2014), and later in a more extended publication with coauthors (Jordan et al., 2014), Jordan presents a vision of forecast and prediction problems of earthquake system science. As experienced practitioners and in full appreciation of scientific studies on earthquake forecasting, we find it necessary to share a complementary viewpoint
Further Remarks on Extra Roots of Rayleigh Equation and Somigliana Waves
The extra roots of the Rayleigh equation for an elastichalfspace contribute to the solution only for large enough values of thePoisson coefficient (a > 0.309). One of them corresponds to leaking modeswith the phase velocity less than the velocity of the longitudinal wave.A similar wave with distinct dispersion may exists in the case where anelastic halfspace is covered by a thin layer with lower velocities of elasticwaves. The thickness of a layer should be not too small in comparisonwith the wave length
Controlling selectivity in alkene oxidation : anion driven syn-dihydroxylation or epoxidation catalysed by [Iron(III)(Pyridine-Containing Ligand)] complexes
The introduction of a pyridine moiety into the skeleton of a polyazamacrocyclic ligand affects both thermodynamic properties and coordination kinetics of the resulting metal complexes.1 These features have engendered a great interest of the scientific community. Much of the efforts in the use of macrocyclic pyridine containing ligands have been devoted to the study of catalytic oxidation reactions.2 We report here the synthesis and characterisation of [Fe(III)Pc-L\u2019s)] complexes (Pc-L = Pyridine-Containing Ligand) and their catalytic applications in alkene oxidation reactions using H2O2 as the terminal oxidant under mild conditions (Figure). Depending on the anion employed for the synthesis of the iron(III) metal complex, we observed a completely reversed selectivity. When X = OTf, a selective syn-dihydroxylation reaction was observed. On the other hand, employing X = Cl, we obtained the epoxide as the major product. It should be pointed out that under otherwise identical reaction conditions, using FeCl3\ub76H2O as catalyst in the absence of the ligand, no reaction was observed
A web application prototype for the multiscale modelling of seismic input
A web application prototype is described, aimed at the generation of
synthetic seismograms for user-defined earthquake models. The web application
graphical user interface hides the complexity of the underlying computational
engine, which is the outcome of the continuous evolution of sophisticated
computer codes, some of which saw the light back in the middle '80s. With the
web application, even the non-experts can produce ground shaking scenarios at
the local or regional scale in very short times, depending on the complexity of
the adopted source and medium models, without the need of a deep knowledge of
the physics of the earthquake phenomenon. Actually, it may even allow neophytes
to get some basic education in the field of seismology and seismic engineering,
due to the simplified intuitive experimental approach to the matter. One of the
most powerful features made available to the users is indeed the capability of
executing quick parametric tests in near real-time, to explore the relations
between each model's parameter and the resulting ground motion scenario. The
synthetic seismograms generated through the web application can be used by
civil engineers for the design of new seismo-resistant structures, or to
analyse the performance of the existing ones under seismic load.Comment: 23 pages, 13 figure
Numerical and Experimental Acoustic Performance Investigations of a High-Speed Train Composite Sandwich Panel
Present work focuses on the implementation of
numerical and experimental analyses aimed to acoustic performances
characterization of a composite sandwich panel used for a high-speed
train. Firstly, an experimental and a numerical modal analyses are
presented. Starting from both FE simulation and impact testing
outcomes, it has been possible to carry out a correlation study
through the computation of the Modal Assurance Criterion (MAC).
Good agreement between numerical and experimental analyses has
been found, therefore the definition of a reliable FE model has been
obtained without the necessity of implementing a sensitivity and
updating procedure. In this paper, to find a convenient and accurate
mean for predicting the panel Transmission Loss parameter, the panel
is modeled as a composite sandwich panel, and its TL is predicted
with the hybrid FE&SEA (Statistical Energy Analysis) method. The
TL result is then compared to the experimental one, carried out
through the employment of an intensity sound probe. A very good
accordance has been found allowing to use such numerical procedure
for further acoustic performances improvements. Hence, future
developments could regard the possibility to implement a Reverse
Engineering procedure, in order to realize an optimization process by
considering different materials and stratifications or different panel
thicknesses, to improve the acoustic attenuation properties at those
frequencies at which a worse acoustic behavior of the panel, is
present
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