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A numerical study is conducted for natural convection dominated melting inside discretely heated rectangular enclosures. This study finds applications in the design and operation of thermal energy storage units and the cooling of electric equipment. Results show the benefits of discrete heating over uniform heating for optimizing the melting process. For enclosures of high aspect ratios (A ∼> 4), configurations leading to well controlled heat source temperatures and long melting times are obtained. For cavities of low aspect ratios (A ∼< 4), it is found that the source span η is the most influential parameter. For η ∼ < 0.45, the melting times are shorter and the heat source temperatures remain equal and moderate during the entire melting process. A map for determining the cavity size and the source distribution that optimizes the melting process is presented.

While training students to new literacy and critical thinking has been recognized for several decades, it seems even more crucial today as education is presented as a lever to fight against fake news. Preservice teachers, both so-called digital natives at the cutting edge of the social web and tomorrow’s educators, represent a useful object of study. The purpose of this paper is to describe preservice teachers’ critical thinking skills scores notably regarding environmental factors (training type, country of study and employment) and personal determinants (metaliteracy self-efficacy and belief in the likelihood to become a teacher) in three French-speaking nations (Wallonia, France and Quebec).

Using a quantitative methodology, this article is part of sequential mixed design research aiming to describe the level of preservice teachers’ (n = 245) critical thinking in three French-speaking nations: Wallonia, France and Quebec. This study aimed to see to what extent critical thinking skills (measured with a translated version of the Halpern Critical Thinking Assessment; Halpern, 2016) can notably be influenced by metaliteracy self-efficacy (MASE). Metaliteracy is a concept that aims to join information, digital and media literacy providing a comprehensive framework “for engaging with individuals and ideas in digital environments” (Mackey and Jacobson, 2011, p. 70).

This study establishes the influence of individual determinants such as the feelings of self-efficacy in metaliteracy as well as the belief in the likelihood of becoming a teacher. This study proposes a model predicting the critical thinking skills based on self-efficacy in critical thinking and metaliteracy, the type of training and the interaction between employment and the country of study.

Considering contemporary information issues and infodemic phenomena, critical thinking skills should be developed among preservice teachers. There is a significant positive correlation between MASE and critical thinking skills. Pre-service teachers’ country of study, as well as their training trajectory, seems to influence their critical thinking skills. Involvement in professional life also appears to promote critical thinking skills.

The purpose of this paper is to conduct a numerical study to analyze the melting process along a vertical wavy surface with uniform surface temperature.

The cavity horizontal walls are insulated while the left hot wavy wall and the right cold wall are maintained at temperatures, TH=38.3°C and TC=28.3°C, respectively. The enclosure was filled by solid Gallium initially at temperature TC. A numerical code is developed using an unstructured finite-volume method and an enthalpy porosity technique to solve for natural convection coupled to solid-liquid phase change. The validity of the numerical code used is ascertained by comparing the results with previously published results.

The effect of number of wavy surface undulation and amplitude of the wavy surface on the flow structure and heat transfer characteristics is investigated in detail. The numerical results show that the enhanced total heat transfer rate seems to depend on the amplitude of the wavy surface.

Flow and heat transfer from irregular surfaces are often encountered in many engineering applications to enhance heat transfer such as micro-electronic devices, flat plate solar collectors and flat-plate condensers in refrigerators, etc. Roughened surfaces could be used in latent storage systems where the wall heat flux is known. One of the reasons why a roughened surface is more efficient in heat transfer is its capability to promote fluid motion near the surface; in this way a complex wavy surface is expected to promote a larger heat transfer rate than a flat plate. This complex geometry will promote a correspondingly complicated motion in the fluid near the surface; this motion is described by the nonlinear boundary-layer equations.