Authors:R. Ozao, H. Ogura, M. Ochiai, and S. Tsutsumi
A DSC method for evaluating the surface area of etched Al foils for use in high performance electrolytic capacitors is presented. A linear relationship between the etching degree (effective surface area) and the thermal resistance of the sample is obtained by means of DSC, based on the transient phenomenon. This method using the transient state in DSC measurement is not only novel, but also rapid and simple in evaluating the surface area of an etched aluminum foil. The method is effective even when the Al foil has a naturally oxidized surface.
The spiral plate heat exchanger (SHE) is widely used in plenty of industrial services in full counter current flow liquid-liquid
heat exchange. We have produced a thermal modelling of the heat exchanges in both steady-state and time dependent cases with
2D spiral geometry, allowing computation with different materials, forced convective heat transfer models in turbulent flow
and geometrical parameters options. We will display here some results in steady-state conditions in order to improve the exchanger
Authors:R. Ozao, M. Ochiai, Y. Ichimura, H. Takahashi, and T. Takano
The previously described method involving the use of transient DSC was applied to pharmaceutical powder compacts and to ceramic
powder compacts. The samples were prepared by compressing powders of pentaerythritol tetraacetate and two kinds of alumina
powder (differing in particle size distribution) up to a pressure of 20 MPa by using a jig. For pentaerythritol tetraacetate,
a linear relationship was obtained between the parameter obtained by DSC and the compaction pressure.
Authors:A. Joly, J. Joly, J. Veau, and E. Karmazsin
This work presents the modelling of heat transfer in a polymer sample submitted to a microwave field in the quartz column
of a dilatometer surrounded by vacuum to avoid convection. The temperature rise is studied in transient state by the finite
element method. It is assumed that a uniform and constant heat production is maintained in the entire volume of the sample.
It is shown that it is possible to design the set composed of the sample and of the column to achieve a nearly uniform temperature
in the whole volume of the sample while its temperature is raised from 20 to 250°C at a heating rate of 5 deg·min−1.
Authors:Zakariae Kahot, Rachid Dkiouak, and Abdellatif Khamlichi
This work was dedicated to assessing reliability of slope stability in earthen dams following rapid drawdown. Modeling of the problem physics was based on saturated-unsaturated seepage flow through the nonlinear Richards equation, under the assumption of two-dimensional approximation in steady state and transient state. The modeling of seepage taking place inside the earth dam infill materials included soil parameters, the negative pore water pressure-hydraulic conductivity relationship as well as the negative pore water pressure-volumetric water content. Slope stability was analyzed by using safety factor as evaluated by the Bishop's simplified method. Solution of the governing equations in terms of pore water pressure and fluid flow velocity was performed by using the modules SEEP/W and SLOPE/W of the Finite Element based software package GeoStudio. The drawdown phenomenon was then analyzed and its influence on dam stability assessed by using surface response method and Monte Carlo simulation. A design formula was proposed in order to bound the probability of failure associated to slope stability.
Authors:Andrej Šoltész, Dana Baroková, Zinaw Dingetu Shenga, and Michaela Červeňanská
natural groundwater regime), it is only possible if the mathematical model is calibrated properly for the current state of the so-called ‘normal’ steady state and then for the transientstate. The boundary of the model was set based on groundwater water