Influence Of Different Approaches Research Articles

Improvement of the water resistance of poly(vinyl acetate) emulsion wood adhesive

Four different approaches were taken to improve the water resistance of poly(vinyl acetate) (PVAc) emulsion adhesives. The improved wood adhesives were tested according to the ISO 9020 standard. Tensile storage modulus (E’) and glass transition temperature of the polymer films were measured using dynamic mechanical thermal analysis to quantify the influence of different approaches on those variables. Gel fraction and swelling ratio of the polymer film were measured to evaluate internal crosslink density. The experimental results showed that blending melamine/urea/formaldehyde (MUF) resin with PVAc emulsions modified the water resistance considerably and the film had a high E’ since an interpenetrating network‐type structure was formed in the polymer. The advantages and limitations of each modification were assessed on the basis of comparison of the results.

Ice Accretion Prediction on Multielement Airfoils

The aim of this paper is to present the Italian icing computational environment code, I 2 CE, developed by CIRA, and discuss its evaluation for ice accretion on single and multielement airfoils. The aerodynamic module of the code is based on a potential panel method, whereas the thermodynamic module is based on the classic Messinger model. Different ways to solve the time-dependent ice accretion problem have been taken into account. A comparison between theoretical calculations using multi-time-step, single-time-step, or predictor-corrector procedures and experimental data has been carried out. The effect of the flowfield viscosity on droplet trajectories and the influence of different approaches for the convective heat exchange coefficient calculation have been considered. The influence on the impingement of the actual droplet size distribution has been taken into account and a comparison with a standard median volumetric diameter calculation is presented