Kinetic and MD modelling of automotive fuel droplets heating and evaporation: recent results

[EN] Recent results of the investigation of kinetic and molecular dynamics (MD) models for automotive fuel droplet heating and evaporation are summarised. The kinetic model is based on the consideration of the kinetic region in the close vicinity of the surface of the heated and evaporating droplets, where the motion of molecules is described in terms of the Boltzmann equations for vapour components and air, and the hydrodynamic region away from this surface. The effects of finite thermal conductivity and species diffusivity inside the droplets and inelastic collisions in the kinetic region are taken into account. A new self-consistent kinetic model for heating and evaporation of Diesel fuel droplets is briefly described. The values of temperature and vapour densities at the outer boundary of the kinetic region are inferred from the requirement that both heat flux and mass flux of vapour components in the kinetic and hydrodynamic regions in the vicinity of the interface between these regions are equal. At first, the heat and mass fluxes in the hydrodynamic region are calculated based on the values of temperature and vapour density at the surface of the droplet. Then the values of temperature and vapour density at the outer boundary of the kinetic region, obtained following this procedure, are used to calculate the corrected values of hydrodynamic heat and species mass fluxes. The latter in their turn lead to new corrected values of temperature and vapour density at the outer boundary of the kinetic region. It is shown that this process quickly converges and leads to self-consistent values for both heat and mass fluxes. Boundary conditions at the surface of the droplet for kinetic calculations are inferred from the MD calculations. These calculations are based on the observation that methyl (CH3) or methylene (CH2) groups in n-dodecane (approximation of Diesel fuel) molecules can be regarded as separate atom-like structures in a relatively simple United Atom Model. Some results of the application of quantum chemical methods to the estimation of the evaporation/condensation coefficient are discussed.The authors are grateful to the EPSRC (UK) (grants EP/K005758/1, EP/K020528/1 and EP/M002608/1), the Royal Society (UK) (grant IE 160014) and the Russian Foundation for Basic Research (grant No. 17-08-01274) for their financial support.Sazhin, S.; Shishkova, I. (2017). Kinetic and MD modelling of automotive fuel droplets heating and evaporation: recent results. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 1076-7082. https://doi.org/10.4995/ILASS2017.2017.4593OCS1076708

The influence of acid rain and drought on early growth and development of jack pine and balsam poplar

The influence of "acid rain" (watering with tap water acidified to pH 3.0 ) and drought on jack pine seedlings and balsam poplar cuttings growing in two different soil types was studied in a short-term greenhouse experiment. Changes in soil chemistry were assessed and a number of growth parameters and physiological processes measured. Irrigation with "acid rain" led to rapid soil acidification. It resulted in decreased soil pH, cation exchange capacity and base saturation, and altered concentrations of the basic exchangeable ions; the level of Al’” increased, while the levels of Ca*', Mg”and K’ decreased. There was a slight decrease in total soil organic matter and a slight increase in soil nitrogen. Drought generally enhanced the adverse effects of the soil acidification process. “Acid rain" had a beneficial effect on seedling and cutting growth and development. Height and diameter growth, development of root surface area, production of aboveground and belowground biomass were stimulated by "rain" with pH 3.0. Seedlings and cuttings watered with "acid rain" also had lower water saturation deficit, lower diffusive resistance and higher transpiration rates. Changes in leaf chlorophyll fluorescence indicated slight stimulation of photosynthesis. Drought reduced seedling and cutting growth and development, but "rain" with pH 3.0 significantly reduced these adverse effects. Both tree species responded in a similar way to the stress factors. Plants performed better in the lighter soil because of better growth conditions. For early tree growth and development, "acid rain" was not directly harmful even when combined with drought

Improving Reading in Adolescents and Adults With High-Functioning Autism Through an Assistive Technology Tool: A Cross-Over Multinational Study.

People with autism spectrum disorder (ASD) experience reading comprehension difficulties, often misinterpreting complex texts, metaphors, and idioms. We have developed and tested a new assistive technology tool for adaptive, personalized text simplification, called Open Book. This tool is an open-sourced, online platform that uses Natural Language Processing with the specific aim of assisting reading and aiding understanding of written text for people with ASD. The accessibility and effectiveness of Open Book was tested by examining the differences in text comprehension scores between the original texts and texts that were simplified by Open Book tool, randomly allocated to study participants. Two hundred forty-three participants (153 adults and 90 adolescents) with high-functioning ASD were recruited in the UK, Spain, and Bulgaria. Regarding the primary outcome, results showed that both adults and adolescents with ASD gave more correct answers for the simplified (M = 11.2, SD = 4.1) than original texts (M = 10, SD = 4.1; p < 0.001). This finding was consistent across age groups and countries. Regarding the secondary outcome, when participants were asked to blindly rate how easy was to understand each text, simplified texts were rated as easier (M = 7.6, SD = 2.4) to understand than the original texts (M = 8.7, SD = 2.6; p < 0.001). The Open Book software seems to have the potential to be a useful tool in assisting reading among people with ASD. Our findings support our primary hypothesis that texts simplified through Open Book were easier to comprehend compared to original texts

A solution of the Boltzmann equations in the presence of three components and inelastic collisions

AbstractA new algorithm for the solution of the system of three Boltzmann equations for three components in a mixture is developed. Binary collisions between molecules are taken into account assuming that these collisions are elastic or inelastic. The functionality testing of the algorithm is performed using a simple test problem of heat and mass transfer in the mixture of n-dodecane, p-dipropylbenzene and nitrogen between two infinite parallel walls. The mixture of n-dodecane and p-dipropylbenzene is chosen due to the fact that it can approximate realistic Diesel fuels reasonably well. It is concluded that the predictions of the new kinetic algorithm are qualitatively consistent with the predictions of more basic models of the phenomena for which it has been tested. The algorithm is ready for the analysis of a wider range of heat and mass transfer problems in which the contribution of three components in the mixture is essential

Methodology for Training Teachers in Basic and Specific Computer Skills

This article describes methodology for training teachers in Maths, Physics, Astronomy and Professional subjects in basic and specific computer skills