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This paper presents a fundamental study of electro-thermo-convective flows within a layer of dielectric liquid subjected to both an electric field and a thermal gradient. A low-conductivity liquid enclosed between two horizontal electrodes and subjected to unipolar charge injection is considered. The interplay between electric and thermal fields ignites complex physical interactions within the flows, all governed by a set of coupled electro-thermo-hydrodynamic equations. These equations include Maxwell, Navier–Stokes, and energy equations and are solved numerically using an in-house code based on the finite volume method. Electro-thermo-convective flows are driven by two dimensionless instability criteria: Rayleigh number Ra and the stability parameter T, and also by the dimensionless mobility parameter M and Prandtl number Pr. The electric Nusselt number (Ne) analogue to the Nusselt number (Nu) in pure thermal problems serves as an indicator to monitor the shift from a thermo- to an electro-convective flow and its eventual evolution into unsteady, and, later, chaotic flow. This change in regime is observed by tracking the electric Nusselt number's behavior as a function of the stability parameter (T), for different values of the non-dimensional parameters (M, Ra, and Pr). The important role of mobility parameter M for the development of the flow is shown. The flow structure during different development stages in terms of the number of convective cells is also discussed. [ABSTRACT FROM AUTHOR]

This article investigates the behavior of two parallel layers of different miscible dielectric liquids enclosed and sandwiched between two electrodes. By applying an electric potential to one electrode while grounding the other, electro-convection occurs when the electric Rayleigh number exceeds a critical value, setting the fluid into motion and resulting in rapid mixing between the two liquids. A numerical model is developed to account for the varying ionic mobility and permittivity of the two liquids, considering their evolution based on the relative concentration field. The simulations confirm that electro-convection significantly enhances the mixing between the two liquids, as expected. Additionally, intriguing ripples are observed near the initial interface during the early stages of electro-convection instability growth. To explain and describe the flow dynamics in terms of stability analysis, a semi-analytical model is presented. This study provides insights into the mixing behavior and flow dynamics of miscible dielectric liquids under the influence of electro-convection. The findings contribute to a better understanding of the underlying mechanisms and can be valuable for applications such as microfluidics, energy conversion, and mixing processes. Further research is encouraged to explore additional parameters and optimize the control of electro-convection for practical applications. [ABSTRACT FROM AUTHOR]

Objective. The purpose of this study was to determine the clinical and biological characteristics at diagnosis in children and adolescents with chronic myelogenous leukemia (CML) in contemporary practice. Methods. Analysis was conducted on data from 3 prospective trials conducted in children and adolescents with CML. Forty pediatric patients were evaluated in 16 French pediatric oncology units between 1991 and 2003. Results. The disease predominately affected children who were older than 10 years (67% of the patients), with a higher prevalence in boys than gifts (gender ratio: 1.5). Approximately 20% of cases were diagnosed incidentally. The main presenting symptoms were asthenia, weight loss, and complaints related to splenomegaly. Occasional patients presented with signs evocative of leukostasis. Symptoms were more common in patients with splenic enlargement, which was present in 70% of patients, and higher leukocyte counts. Markedly raised leukocyte counts were common (median white blood cell count: 242 x [10.sup.9]/L). The age and the gender of the patients had no effect on the leukocyte count, the hemoglobin level, or the platelet count. A predominance of b3a2 transcript was observed in the 16 children who were studied for the type of chimeric BCR-ABL mRNA. Conclusions. This is largest reported series of CML at diagnosis in children and adolescents. It shows that the characteristics of CML seem to differ in children compared with previously published adult series; in particular, the presenting leukocyte counts are often higher in children. Pediatrics 2005;116:140-143; children, leukostasis, chronic myelogenous leukemia. ABBREVIATIONS. CML, chronic myelogenous leukemia; WBC, white blood cell., Chronic myelogenous leukemia (CML) is a very rare disease in children, accounting for 2% to 3% of leukemias in children and adolescents with an annual incidence of 1 case per [...]