Effect of RF magnetron sputtering parameters on the optimization of the discharge capacity of ternary lithium oxide thin films

Journal of Materials Science: Materials in Electronics - The increasing demand for lithium-ion batteries has stimulated the investigation of new compounds in order to reduce the costs and the...     

Study of some factors involved in ethanal production during alcoholic fermentation

The influence of temperature, turbidity and oxygen uptakes to the musts on the production of ethanal by yeasts, during the alcoholic fermentation (AF), has been studied. The aim was to evaluate how increasing and controlling the production of this molecule, in order to anticipate the reactions between anthocyanins and flavans from the second half of the AF. This concerns, in particular, those winemaking techniques consisting in a temporarily separate fermentation of a part of the must (35–40% of the total mass), that is drained before the start of the AF. The experimental design was a complete factorial plan with three factors upon two levels (T = 18 °C and 22 °C; with or without oxygen; turbidity of 30 and 120 NTU); data were elaborated with 3-ways ANOVA. Temperature proved to be the main factor influencing ethanal production during AF: higher temperatures (22 °C versus 18 °C) cause an increase of the ethanal content during the first days of fermentation; after having reached 6–7% of ethanal, the effect is inverted. The influence of turbidity is less important, and it's synergic with the effect of temperature. Oxygen has a detrimental effect on the production of ethanal only at the beginning of the AF, while later, in presence of ethanol, it promotes it through a chemical way.     

Thermal conductivity studies on ceramic floor tiles

Thermal diffusivity, thermal conductivity and specific heat of several materials used as floor tiles have been measured using the laser flash method. Natural stones, particularly granite, porcelain stoneware and red stoneware materials of low water absorption, are more effective thermal conductors than white stoneware and vinyl, which have thermal conductivities below 1 W m⁻¹ K⁻¹. Therefore, last two should not be recommended for radiant floor heating applications. Enhancement of thermal conductivity of red and porcelain stoneware has been achieved by adding Al₂O₃ of certain characteristics to the ceramic paste. In this way, thermal diffusivity increases of up to 50% have been obtained by adding 20 wt.% of Al₂O₃ particles.     

Discharge and the Eccentricity of the Hopper Influence on the Silo Wall Pressures

The objective of this work is to perform an analysis of pressure distributions in grain silos for both the discharge and static conditions with eccentric outlets. To this end, the commercial ANSYS program, based on the finite-element method is employed. In this paper, results are presented for a silo with a height of 10.5 m (cylinder height 8 m, base cone height 2.5 m), a silo radius of 3 m, and an outlet radius of 0.5 m. Outlet eccentricity ranged from 0% (central outlet) to 100% (maximally eccentric outlet, tangential to the silo cylinder). Based on the results, this paper proposes new methods of analyzing silo discharge and the influence of outlet eccentricity. The discharge model combines both dilatancy and type of discharge effects. 3D models were developed to analyze the eccentricity of the outlet. The results are compared with previous research data and with standard design guidelines.     

Modelling of the mechanical properties of Castanea sativa Mill. structural timber by a combination of non-destructive variables and visual grading parameters

Linear regression models were constructed for chestnut beams of Spanish origin (Asturias, Galicia, Catalonia and Extremadura) using the global modulus of elasticity (MOE _g ) and bending strength (MOR), both obtained by destructive tests, as dependent variables, and the results of non-destructive measurements, visual grading parameters and density as independent variables. The variables selected were density, wave velocity, sample length, dynamic modulus of elasticity, maximum knot diameter in relation to height and concentrated knot diameter ratio. Linear regression models were constructed to indirectly estimate the mechanical properties of the beams. Ultrasonic velocity, density and sample length were the best predictors of MOE _g (R ²?=?0.740 and 0.734 SE). Regression adjustments for MOR presented low coefficients of determination and high errors. The visual grading parameters of the beams did not play a significant role in the prediction of either MOE _g or MOR.     

Influence of Hopper Eccentricity on Discharge of Cylindrical Mass Flow Silos with Rigid Walls

The influence of hopper eccentricity on silo discharge has always concerned researchers. Eccentric discharge brings about asymmetries in the distribution of normal pressures, the values of which are not known with precision. This study presents a three-dimensional model of the dynamic discharge of a silo with an eccentric hopper, considering the Drucker-Prager plasticity model for the behavior of stored material. The results obtained for different hopper eccentricities reveal that pressures decrease in the hopper along the generatrix of the silo above the outlet, as compared to the opposite side. An increase in normal pressures occurs at this generatrix, as compared to the diametrically opposite generatrix, in the lower part of the cylindrical wall above the silo-hopper transition.