Search results for "Thermal"
showing 10 items of 3576 documents
Experimental Study on the Performance of Timber Frame Wall Panels in Mediterranean Construction
2018
Only recently, the use of wooden buildings is spreading in the central and southern parts of the Italy due to national and EU policies on eco-sustainability and energy saving. Knowledge of the durability of the building envelope elements, generally made with dry assembled stratified systems, is still insufficient. The paper presents the first results of a durability evaluation of multilayer timber panel applied to Platform Frame System buildings, focusing on the variation of energy performance over time. The case study describes the construction of two single-family houses in the municipality of San Cataldo (Sicily, Italy). The used timber multilayer panel presents a stratigraphy suitable f…
Prediction of structural and thermodynamic properties of zinc-blende AlN: molecular dynamics simulation
2004
Abstract Structural and elastic properties of AlN are investigated by using a molecular dynamics simulation based on the Tersoff empirical interatomic potential. Both of zinc-blende and rock-salt structures are discussed. The calculated bulk properties and elastic constants agree well with the available experimental and theoretical data. The Thermodynamic properties in zinc-blende structure are also predicted including the Debye temperature, melting temperature, heat capacity, linear thermal coefficient. This study is helpful to understand the bahviour of physical properties of AlN when the temperature varies.
Mercury fluxes from volcanic and geothermal sources: an update
2014
We review the state of knowledge on global volcanogenic Hg emissions to the atmosphere and present new data from seven active volcanoes (Poás, Rincón de la Vieja, Turrialba, Aso, Mutnovsky, Gorely and Etna) and two geothermal fields (Las Pailas and Las Hornillas). The variability of Hg contents (c. 4–125 ng m−3) measured in gaseous emissions reflects the dynamic nature of volcanic plumes, where the abundances of volatiles are determined by the physical nature of degassing and variable air dilution. Based on our dataset and previous work, we propose that an average Hg/SO2 plume mass ratio of c. 7.8×10−6 (±1.5×10−6; 1 SE, n=13) is best representative of open-conduit quiescent degassing. Takin…
Effect of preparation method on the properties of poly(methyl methacrylate)/mesoporous silica composites
2019
The preparation method of a polymer composite and the filler loading are amongst the factors that influence the properties of the final composites. This article studies the effect of these factors on the thermal stability and thermal degradation kinetics of poly(methyl methacrylate) (PMMA)/mesoporous silica (MCM-41) composites filled with small amounts of MCM-41. The PMMA/MCM-41 composites were prepared through in situ polymerisation and melt mixing methods, with MCM-41 loadings of 0.1, 0.3, and 0.5 wt.%. The presence of MCM-41 increased the thermal stability of PMMA/MCM-41 composites prepared by melt mixing, but in the case of the in situ polymerised samples, the MCM-41 accelerated the deg…
Morphology, interfacial interaction, and thermal degradation of polycarbonate/MCM-41 (nano)composites
2017
ABSTRACTThis article reports on the morphology, interfacial interaction, thermal stability, and thermal degradation kinetics of polycarbonate (PC)/mesoporous silica (MCM-41) composites with various MCM-41 contents, prepared by melt compounding. The composites with low filler loadings (<0.3 wt%) maintained their transparency because of the well dispersed MCM-41 particles, but at higher filler loadings the composites lost their transparency due to the presence of agglomerates. The presence of agglomerates decreased the thermal stability of PC due to the reduced effectiveness of the particles to immobilize the polymer chains, free radicals, and volatile degradation products.
Monsoon onset over Sudan-Sahel: Simulation by the regional scale model MM5.
2006
[1] The Mesoscale Model MM5 is used to study the regional features of the West African Monsoon onset. In order to increase the results, simulations are carried out for eight consecutive seasons (March to September) of the years 1994 to 2001. The results show that the model can reproduce the dynamical features of the monsoon in a reasonably good manner but the seasonal cycle seems enhanced. It is hypothesized that overestimated rainfall amounts could be related to a poor representation of the land surface characteristics. Nevertheless, the mean simulated monsoon onset dates are similar to those find in the CMAP data set. The onset is characterized by an apparent increase in zonal flow that c…
Dielectric response of nanoscopic spherical colloids in alternating electric fields: a dissipative particle dynamics simulation.
2012
We study the response of single nanosized spherical colloids in electrolyte solution to an alternating electric field (AC field) by computer simulations. We use a coarse-grained mesoscopic simulation approach that accounts in full for hydrodynamic and electrostatic interactions as well as for thermal fluctuations. The solvent is modeled as a fluid of single Dissipative Particle Dynamics (DPD) beads, and the colloidal particle is modeled as a rigid body made of DPD beads. We compute the mobility and the polarizability of a single colloid and investigate systematically the effect of amplitude and frequency of the AC-fields. Even though the thickness of the Debye layer is not "thin" compared t…
Orientational dynamics of fluctuating dipolar particles assembled in a mesoscopic colloidal ribbon
2017
We combine experiments and theory to investigate the dynamics and orientational fluctuations of ferromagnetic microellipsoids that form a ribbonlike structure due to attractive dipolar forces. When assembled in the ribbon, the ellipsoids display orientational thermal fluctuations with an amplitude that can be controlled via application of an in-plane magnetic field. We use video microscopy to investigate the orientational dynamics in real time and space. Theoretical arguments are used to derive an analytical expression that describes how the distribution of the different angular configurations depends on the strength of the applied field. The experimental data are in good agreement with the…
Dynamical and statistical properties of high-temperature self-propagating fronts: An experimental study
2009
International audience; We present a detailed experimental study of high-temperature self-propagating fronts using image processing techniques. The intrinsic features of the wave propagation are investigated as a function of the combustion temperature TC for a model system made of titanium and silicon powders. Different front behavior is realized by changing the molar ratio x of the mixture Ti+xSi. Outside the range x=[0.3,1.5], no thermal front is propagating while inside, three regimes are observed: steady-state combustion which is characterized by a flat front propagating at constant velocity and two unsteady regimes. The combustion temperature (or the corresponding ratio x) is thus play…
Ultralow thermal conductivity in 1D and 2D imidazolium-based lead halide perovskites
2021
Low-dimensional hybrid organic–inorganic metal halide perovskites are rapidly emerging as a fascinating sub-class of the three-dimensional parent structures, thanks to their appealing charge and thermal transport properties, paired to better chemical and thermal stabilities. Extensive investigations of the thermal behavior in these systems are of paramount relevance to understand their optoelectronic and thermoelectric applications. Herein, we present a complete thermophysical characterization of imidazolium lead iodide, (IMI)PbI3, a 1D pseudo-perovskite with chains of face-sharing octahedra, and histammonium lead iodide, (HIST)PbI4, a 2D layered perovskite with corner-sharing octahedra. Up…