Navigating social spaces: armed mobilization and circular return in Eastern DR Congo

This article discusses the social mobility of combatants and introduces the notion of circular return to explain their pendular state of movement between civilian and combatant life. This phenomenon is widely observed in eastern Democratic Republic of Congo (DRC), where Congolese youth have been going in and out of armed groups for several decades now. While the notion of circular return has its origins in migration and refugee studies, we show that it also serves as a useful lens to understand the navigation capacity between different social spaces of combatants and to describe and understand processes of incessant armed mobilization and demobilization. In conceptualizing these processes as forms of circular return, we want to move beyond the remobilization discourse, which is too often connected to an assumed failure of disarmament, demobilization, and reintegration processes. We argue that this discourse tends to ignore combatants’ agency and larger processes of socialization and social rupture as part of armed mobilization.

Capillary Cohesion between Two Spherical Glass Particles

For developing a unique model in which the rheological performance of fresh concretes from zero-slump to self compacting concrete can be described, it is necessary to define workability in terms of fundamental physical entities. In order to achieve this, the concept of capillary cohesion from science of granular physics has been considered as the first step for investigation. In this paper, focus is on this concept and providing some preliminary achievements of the experimental work. In wet granular material the presence of liquid generates cohesion between particles and affects the mechanical properties of the granular media to a large extent. For the simulation of the behavior of this material by considering pendular state for liquid content, a discrete element method (DEM) is used. The cohesion between a grain-pair is expressed as an explicit function of local geometrical and physical parameters. In this study emphasis is on static and/or quasi-static situations. Since the cohesion dominates over other effects of the liquid, such as viscosity and lubrication, the effect of the size of particles on the cohesion arising from the liquid bridge is investigated explicitly. Based on experimental results, a closed-formula approximation is developed that can be used to calculate the capillary force acting between two glass spheres as a function of the separation distance for a given bridge volume.

Development of Eco-Debinding Process Using Supercritical Extraction of Low Molecular Organic Binders in Ceramic Bodies with Nano-Sized Capillary Structure

Eco-debinding process using supercritical extraction of low molecular organic binders in nano-porous ceramic bodies was examined. The debinding properties related to structural changes during supercritical extraction and conventional solvent extraction were also compared. The debinding rate of supercritical extraction was significantly enhanced compared to the debinding rate of solvent extraction because of the high diffusivity of the supercritical carbon dioxide for the low molecular weight wax binder in the molded bodies with nano-sized pore structure, although both debinding rates showed same a square root of time dependence. The extraction rates with morphological changes varied depending on the degree of saturation at the end of debinding stages. Both the debinding methods experienced morphological changes with a debinding front separating the pendular state region from the undebinded region with fluid state in low molecular paraffin wax based powder compacts during extraction. The capillary structural changes in the green bodies caused severe defects during extraction and degraded the physical properties. In spite of the abrupt changes of the capillary structure, the debinding defect was significantly alleviated for the supercritical debinded ceramic bodies, compared to the solvent extracted bodies.