L’apport de la liturgie à la conception du décor d’un monument funéraire byzantin : le cas de la chapelle cimétériale de Bačkovo (Bulgarie)

L’examen des monuments byzantins à vocation funéraire révèle de nombreuses lacunes et variations possibles, d’ordre à la fois textuel, architectural et iconographique. Un exemple illustre de cette catégorie spécifique d’édifices – la chapelle cimétériale du monastère de Bačkovo – permet d’ériger la cohérence exceptionnelle entre fonction (sépulcrale) et décor figuré (à caractère salvifique) en sujet d’étude à part entière. L’objectif de la présente investigation sera d’approfondir l’articulat..

Liquid distribution after head-on separation of two colliding immiscible liquid droplets

Head-on collisions of two immiscible liquid droplets lead to a collision complex, which may either remain stable in the form of a single compound drop, or fragment into two main daughter droplets. This paper investigates the liquid distribution developing in the two daughter droplets and which can be of three types. Either two encapsulated droplets (single reflex separation) form, or a single encapsulated drop plus a droplet made solely of the encapsulating liquid, which can be found either on the impact side (reflexive separation) or opposite to it (crossing separation). A large number of experimental and simulation data covering collisions with partial and total wetting conditions and with Weber and Reynolds numbers in the ranges of 2 - 720 and 66 - 1100, respectively, is analyzed. The conditions leading to the three mentioned liquid distributions are identified and described based on the decomposition of the collision in two phases: (i) radial extension of the compound droplet into a lamella and (ii) its relaxation into an elongated cylindrical droplet. In accordance with these two phases, two dimensionless parameters, $\Lambda = {\rho_i/\rho_o} {{We_i}^{-1/2}}$ and $N = {\nu_o/\nu_i}~{\sigma_{o}/\sigma_{io}}$, are derived, which are built on the collision parameters and liquid properties of the encapsulated inner droplet (i) and the outer droplet (o) only. In agreement with the proposed interpretation, the combination of these two parameters predicts the type of liquid distribution. The predictions are found to be in very good agreement with both experimental and numerical results.Comment: the linked dataset https://doi.org/10.18419/darus-3594 will be available shortly after the arXiv submissio

Universality of stretching separation

We develop a parameter-free model for the fragmentation of drops colliding off-center. The prediction is excellent over a wide range of liquid properties. The so-called stretching separation is attributed to the extension of the merged drop above a critical aspect ratio of {3.25}. The evolution of this aspect ratio {is influenced by the liquid viscosity} and can be interpreted via an energy balance. This approach is then adapted to drop-jet collisions, which we model as consecutive drop-drop collisions. {The fragmentation criterion is similar the one observed at drop-drop collisions}, while the evolution of the stretched jet aspect ratio is modified to account for the different flow fields and geometry.Comment: 11 pages, 4 figures and supplementary materia

Drop Stream – Immiscible Jet Collisions: Regimes and Fragmentation Mechanisms

[EN] We investigate the collision of a continuous liquid jet with a regular stream of immiscible droplets. The immiscible liquids, namely silicon oil for the continuous jet and an aqueous glycerol solution for the drop stream, are selected to enable the total wetting of the drops by the jet liquid. Four different regimes are experimentally identified: drops in jet, encapsulation without satellites, encapsulation with satellites from the jet liquid and mixed fragmentation. The drops in jet regime, potentially of great interest for new applications, corresponds to a regular stream of drops embedded in a continuous jet and is described and reported for the first time. Using well known aspects of drop collision and jet stability, we propose to model the transition between the drops in jet regime and the others. Two dimensionless parameters are derived from this analysis which are thus used to produce a simple regime map where the drops in jet regime can be well distinguished from the other outcomes.Planchette, C.; Hinterbichler, H.; Brenn, G. (2017). Drop Stream – Immiscible Jet Collisions: Regimes and Fragmentation Mechanisms. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 723-729. https://doi.org/10.4995/ILASS2017.2017.4707OCS72372

Unjamming strongly compressed particle rafts

We experimentally study the unjamming dynamics of strongly compressed particle rafts confined between two fixed walls and two movable barriers. The back barrier is made of an elastic band, whose deflection indicates the local stress. The front barrier is pierced by a gate, whose opening triggers local unjamming. The rafts are compressed by moving only one of the two barriers in the vicinity of which folds form. Using high speed imaging, we follow the folded, jammed, and unjammed raft areas and measure the velocity fields inside and outside of the initially confined domain. Two very different behaviors develop. For rafts compressed by the back barrier, only partial unjamming occurs. At the end of the process, many folds remain and the back stress does not relax. The flow develops only along the compression axis and the particles passing the gate form a dense raft whose width is the gate width. For rafts compressed at the front, quasi-total unjamming is observed. No folds persist and only minimal stress remains, if any. The particles flow along the compression axis but also normally to it and form, after the gate, a rather circular and not dense assembly. We attribute this difference to the opposite orientation of the force chain network that builds up from the compressed side and branchs. For rafts compressed at the gate side, keystone particles are immediately removed which enhances local disentanglement and leads to large scale unjamming. In contrast, for back compressed rafts, the force chain network redirects the stress laterally forming arches around the gate and resulting in a limited unjamming process

Effects of viscosity on liquid structures produced by in-air microfluidics

This paper experimentally investigates the effect of viscosity on the outcomes of collisions between a regular stream of droplets and a continuous liquid jet. A broad variation of liquid viscosity of both the drop and the jet liquid is considered, keeping other material properties unchanged. To do so, only two liquid types were used: aqueous glycerol solutions for the drop and different types of silicone oil for the jet liquid. Combining these liquids, the viscosity ratio {\lambda} = {\mu}drop/{\mu}jet was varied between 0.25 and 3.50. The collision outcomes were classified in the form of regime maps leading to four main regimes: drops in jet, fragmented drops in jet, encapsulated drops, and mixed fragmentation.We demonstrate that, depending on the drop and jet viscosity, not all four regimes can be observed in the domain probed by our experiments. The experiments reveal that the jet viscosity mainly affects the transition between drops in jet and encapsulated drops, which is shifted towards higher drop spacing for more viscous jets. The drop viscosity leaves the previous transition unchanged but modifies the threshold of the drop fragmentation within the continuous jet. We develop a model that quantifies how the drop viscosity affects its extension, which is at first order fixing its shape during recoil and is, therefore, determining its stability against pinch-off.Comment: 18 pages, 7 figure

Importância da má-oclusão na etiologia das cefaleias

Na prática da medicina dentária é frequente observar pacientes com problemas oclusais. Atualmente, o papel da oclusão em relação à etiologia da disfunção temporomandibular (DTM) é amplamente considerado ao iniciar, perpetuar ou predispor a mesma. Pode estar associada com a produção de sintomatologia, especificamente dor de cabeça. Objetivos: ● Verificar a relação entre a má-oclusão e as cefaleias, ● Verificar os tipos diferentes de cefaleias relacionadas com os diferentes tipos de má-oclusão, ● Avaliar a importância clínica da correção dentária e sua relação com a sintomatologia. Metodologia: Foi realizada uma pesquisa eletrónica na base de dados Pubmed e Ebsco, entre os anos 2011 e 2021, com o objetivo de elaborar uma revisão sistemática integrativa. As combinações dos seguintes elementos de pesquisa foram usadas: “headache”, “etiology”, “malocclusion” e “dental occlusion”. A pesquisa identificou 38 estudos, dos quais 14 foram considerados relevantes para este estudo. Resultados: Os resultados dos estudos demonstraram clínica e estatisticamente correlações entre interferências oclusais e cefaleias, especificamente cefaleia por contração muscular (CCT). Conclusão: Diferentes tipos de má-oclusão são associados com cefaleias, especificamente cefaleias tipo tensão (CTT) e enxaquecas. A prevenção do progresso das cefaleias deve ser uma prioridade. Diferentes abordagens podem ser benéficas para os pacientes. A correção dos desequilíbrios oclusais pode favorecer a sua eliminaçã

Optical imaging of the small intestine immune compartment across scales.

The limitations of 2D microscopy constrain our ability to observe and understand tissue-wide networks that are, by nature, 3-dimensional. Optical projection tomography (OPT) enables the acquisition of large volumes (ranging from micrometres to centimetres) in various tissues. We present a multi-modal workflow for the characterization of both structural and quantitative parameters of the mouse small intestine. As proof of principle, we evidence its applicability for imaging the mouse intestinal immune compartment and surrounding mucosal structures. We quantify the volumetric size and spatial distribution of Isolated Lymphoid Follicles (ILFs) and quantify the density of villi throughout centimetre-long segments of intestine. Furthermore, we exhibit the age and microbiota dependence for ILF development, and leverage a technique that we call reverse-OPT for identifying and homing in on regions of interest. Several quantification capabilities are displayed, including villous density in the autofluorescent channel and the size and spatial distribution of the signal of interest at millimetre-scale volumes. The concatenation of 3D imaging with reverse-OPT and high-resolution 2D imaging allows accurate localisation of ROIs and adds value to interpretations made in 3D. Importantly, OPT may be used to identify sparsely-distributed regions of interest in large volumes whilst retaining compatibility with high-resolution microscopy modalities, including confocal microscopy. We believe this pipeline to be approachable for a wide-range of specialties, and to provide a new method for characterisation of the mouse intestinal immune compartment