447 research outputs found
Pollutant emissions in common-rail diesel engines in extraurban cycle: rapeseed oils vs diesel fuel
The new energy strategy of EU (i.e., Directive 2009/28/EC) requires increasing the use of biofuels in transports up to
at least 10% of the total fuel consumption. In the last years, the share of Diesel engines in automotive applications
reached about 55% in EU market, thus trying to widen the alternatives to Diesel fuel is very important. In this
framework straight vegetable oils (SVO) can represent one of the available possibilities at least in some specific
applications (i.e., public transportation, hybrid or marine propulsion, etc.). SVO properties may be very different
form Diesel fuel, thus operating a Diesel engine with SVO might result in some problems, especially in automotive
configuration where the electronic unit acts as if it is working with Diesel fuel. This reflects in possible engine power
and torque reduction, maintenance problems, and pollutant emissions during vehicles running. The latter aspect is the
focus of the present paper. In this work, we used a turbocharged, four stroke, four cylinders, water cooled, commonrail
multijet Diesel engine in automotive configuration to simulate the extraurban cycle according to the EU standard,
comparing pollutant emissions in case of SVO and gasoil fuelling
Letter, 1979 August 15, from Louis P. Rispoli to Gene E. Vollen
1 page, Rispoli was an assistant to Virgil Thomson. Vollen was the Chairman of the Music Department for Pittsburg State University
Investigations on diurnal and seasonal variations of Schumann resonance intensities in the auroral region
Measurements of the magnetic component of the Schumann resonance in the frequency range 6-14 Hz were performed
at high latitude location (TNB Antarctica; geographic coordinates: 74.7°S, 164.1°E; geomagnetic coordinates:
80.0°S, 307.7°E; LT=UT+13; MLT=UT8; altitude=28 m a.s.l.), during the two years 1996-1997. TNB
is a particularly important observation site located in a region characterised by a high electromagnetic activity in the
ELF and VLF bands. Moreover its remote location in Antarctica provides the important advantage that electromagnetic
background noise is not corrupted by anthropogenic noise and that the continental lightning activity is very low.
The combination of low additional anthropogenic electromagnetic radiation and low atmospheric noise in this area
allows detailed investigations into wave generation and amplification in the polar ionosphere and magnetosphere not
possible anywhere else in the world. This paper reports the study of the magnetic power of the 8 Hz Schumann resonance
mode. For both the years considered diurnal and long-term seasonal variations were observed
Investigations on diurnal and seasonal variations of Schumann resonance intensities in the auroral region
Measurements of the magnetic component of the Schumann resonance in the frequency range 6-14 Hz were performed
at high latitude location (TNB Antarctica; geographic coordinates: 74.7°S, 164.1°E; geomagnetic coordinates:
80.0°S, 307.7°E; LT=UT+13; MLT=UT–8; altitude=28 m a.s.l.), during the two years 1996-1997. TNB
is a particularly important observation site located in a region characterised by a high electromagnetic activity in the
ELF and VLF bands. Moreover its remote location in Antarctica provides the important advantage that electromagnetic
background noise is not corrupted by anthropogenic noise and that the continental lightning activity is very low.
The combination of low additional anthropogenic electromagnetic radiation and low atmospheric noise in this area
allows detailed investigations into wave generation and amplification in the polar ionosphere and magnetosphere not
possible anywhere else in the world. This paper reports the study of the magnetic power of the 8 Hz Schumann resonance
mode. For both the years considered diurnal and long-term seasonal variations were observed
Rain erosion numerical modeling applied to multi-MW off-shore wind turbine
In this work, the authors present a numerical prediction of erosion on two different
blade geometry of a 6 MW HAWT designed for different aerodynamic loading, with the aim of studying
their sensitiveness to erosion.
First, the fully 3D simulations are performed using an Euler-Lagrangian approach. Flow field
simulations are carried out with the open-source code OpenFOAM, based on a finite
volume approach, using Multiple Reference Frame methodology. Reynolds Averaged Navier- Stokes
equations for incompressible flow were solved with a k-ε turbulence model.
An in-house code (P-Track) is used to compute the rain drops transport and dispersion,
adopting the Particle Cloud Tracking approach (PCT). The PCT was used by some of the
authors in previous works (Corsini et al., 2012; Corsini et al., 2014) to predict erosion on both
axial and centrifugal fans, obtaining satisfactory results. The PCT allows to simulate a huge
number of transported phase tracking just few cloud trajectories, thus resulting in reduction of
computational time comparing with single particle tracking approach.
Erosion is modelled accounting for the main quantities affecting the phenomenon, which is impact
velocity and angle, and material properties of the target surface.
Results provide the regions of the two blades more sensitive to erosion, and the effect of
the blade geometry on erosion attitude
Rain erosion numerical modeling applied to multi-MW off-shore wind turbine
In this work, the authors present a numerical prediction of erosion on two different
blade geometry of a 6 MW HAWT designed for different aerodynamic loading, with the aim of studying
their sensitiveness to erosion.
First, the fully 3D simulations are performed using an Euler-Lagrangian approach. Flow field
simulations are carried out with the open-source code OpenFOAM, based on a finite
volume approach, using Multiple Reference Frame methodology. Reynolds Averaged Navier- Stokes
equations for incompressible flow were solved with a k-ε turbulence model.
An in-house code (P-Track) is used to compute the rain drops transport and dispersion,
adopting the Particle Cloud Tracking approach (PCT). The PCT was used by some of the
authors in previous works (Corsini et al., 2012; Corsini et al., 2014) to predict erosion on both
axial and centrifugal fans, obtaining satisfactory results. The PCT allows to simulate a huge
number of transported phase tracking just few cloud trajectories, thus resulting in reduction of
computational time comparing with single particle tracking approach.
Erosion is modelled accounting for the main quantities affecting the phenomenon, which is impact
velocity and angle, and material properties of the target surface.
Results provide the regions of the two blades more sensitive to erosion, and the effect of
the blade geometry on erosion attitude
The first Italian COVID-19 lockdown reduced births and voluntary terminations by just under a fifth
No abstract available
Influence of oxidant agent on syngas composition: gasification of hazelnut shells through an updraft reactor
Thermophysical properties of engineering fluids have proven in the past to be essential for the design of physical and chemical processing and reaction equipment in the chemical, metallurgical, and allied industries, as they influence directly the design parameters and performance of plant units in the of, for example, heat exchangers, distillation columns, phase separation, and reactors. In the energy field, the search for the optimization of existing and alternative fuels, either using neutral or ionic fluids, is an actual research and application topic, both for new applications and the sustainable development of old technologies. One of the most important drawbacks in the industrial use of thermophysical property data is the common discrepancies in available data, measured with different methods, different samples, and questionable quality assessment. Measuring accurately the thermal conductivity of fluids has been a very successful task since the late 1970s due to the efforts of several schools in Europe, Japan, and the United States. However, the application of the most accurate techniques to several systems with technological importance, like ionic liquids, nanofluids, and molten salts, has not been made in the last ten years in a correct fashion, generating highly inaccurate data, which do not reflect the real physical situation. It is the purpose of this paper to review critically the best available techniques for the measurement of thermal conductivity of fluids, with special emphasis on transient methods and their application to ionic liquids, nanofluids, and molten salts
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