Finding the refraction law using the ant colony algorithm and the Fermat's principle

editorial reviewe

Controlling the pinning of a receding contact line in a flow coating process

Capillary flow coating is a simple and effective technique to print and assemble ordered nanoparticle-based structures over patterned surfaces. The technique makes use of a nanoparticle suspension confined between two plates. Solvent evaporation and sliding movement of the top plate induce an internal flow that leads to the accumulation of nanoparticles at the bottom receding contact line and to their deposition on the bottom plate. Nevertheless, a comprehensive understanding of the process remains elusive, and in this respect the dynamics of wetting at the receding contact line is known to play a critical role. With the help of large-scale molecular dynamics simulations, we investigate the dynamic contact angle at the receding contact line as well as contact-line pinning on substrate heterogeneities. We develop a model to predict the pinning time of a receding contact line as a function of the displacement speed of the top plate on both chemical and topographical heterogeneities. Confirmation of the dynamic nature of contact-line pinning and justification of the contact line settling time allow us to better describe the time evolution of the receding angle in presence of heterogeneitie

Controlling interface pinning by surface heterogeneities

Doctor blade technique is widely use to coat surface. However the understanding of the interface pinning on surface heterogeneities is still elusive. This work aim to give a better understanding of the process occurring when a liquid interface crosses a heterogeneity while dragged along a surface. For that, large-scale molecular dynamics simulations are used to track the key parameters that determine the movement of a liquid meniscus on a heterogeneous substrate and to give detailed insight of the pinning phenomenon

From wetting dynamics to capillary deposition using large scale molecular dynamics simulations -- Physics

info:eu-repo/semantics/nonPublishe

A new computational framework for simulating airway resistance, fraction of exhaled nitric oxide, and diffusing capacity for nitric oxide.

In this paper, we present a new computational framework for the simulation of airway resistance, the fraction of exhaled nitric oxide, and the diffusion capacity for nitric oxide in healthy and unhealthy lungs. Our approach is firstly based on a realistic representation of the geometry of healthy lungs as a function of body mass, which compares well with data from the literature, particularly in terms of lung volume and alveolar surface area. The original way in which this geometry is created, including an individual definition of the airways in the first seven generations of the lungs, makes it possible to consider the heterogeneous nature of the lungs in terms of perfusion and ventilation. In addition, a geometry can be easily modified to simulate various abnormalities, local or global (constriction, inflammation, perfusion defect). The natural variability of the lungs at constant body mass is also considered. The computational framework includes the possibility to simulate, on a given (possibly modified) geometry, a test to measure the flow resistance of the lungs (including its component due to the not fully developed flow in the first generations of lungs), a test to measure the concentration of nitric oxide in the exhaled air, and a test to measure the diffusion capacity for nitric oxide. This is implemented in the framework by solving different transport equations (momentum and convection/diffusion) describing these tests. Through numerous simulations, we demonstrate the ability of our model to reproduce results from the literature, both for healthy lungs and lungs of patients with asthma or chronic obstructive pulmonary disease. Such a computational framework, through the possibilities of numerous and rapid tests that it allows, sheds new light on experimental data by providing information on the phenomena that take place in the distal generations of the lungs, which are difficult to access with imaging

Refraction law and Fermat principle: a project using the ant colony optimization algorithm for undergraduate students in physics

info:eu-repo/semantics/publishe

Finding the refraction law using the ant colony algorithm and the Fermat’s principle

info:eu-repo/semantics/publishe

Instillation of a Dry Powder in Nasal Casts: Parameters Influencing the Olfactory Deposition With Uni- and Bi-Directional Devices

Nose-to-brain delivery is a promising way to reach the central nervous system with therapeutic drugs. However, the location of the olfactory region at the top of the nasal cavity complexifies this route of administration. In this study, we used a 3D-printed replica of a nasal cavity (a so-called “nasal cast”) to reproduce in vitro the deposition of a solid powder. We considered two different delivery devices: a unidirectional device generating a classical spray and a bidirectional device that relies on the user expiration. A new artificial mucus also coated the replica. Five parameters were varied to measure their influence on the powder deposition pattern in the olfactory region of the cast: the administration device, the instillation angle and side, the presence of a septum perforation, and the flow rate of possible concomitant inspiration. We found that the unidirectional powder device is more effective in targeting the olfactory zone than the bi-directional device. Also, aiming the spray nozzle directly at the olfactory area is more effective than targeting the center of the nasal valve. Moreover, the choice of the nostril and the presence of a perforation in the septum also significantly influence the olfactory deposition. On the contrary, the inspiratory flow has only a minor effect on the powder outcome. By selecting the more efficient administration device and parameters, 44% of the powder can reach the olfactory region of the nasal cast.info:eu-repo/semantics/publishe

The importance of pre-formulation studies and of 3D-printed nasal casts in the success of a pharmaceutical product intended for nose-to-brain delivery

info:eu-repo/semantics/publishe

Instillation of a Dry Powder in Nasal Casts: Parameters Influencing the Olfactory Deposition With Uni- and Bi-Directional Devices

Nose-to-brain delivery is a promising way to reach the central nervous system with therapeutic drugs. However, the location of the olfactory region at the top of the nasal cavity complexifies this route of administration. In this study, we used a 3D-printed replica of a nasal cavity (a so-called “nasal cast”) to reproduce in vitro the deposition of a solid powder. We considered two different delivery devices: a unidirectional device generating a classical spray and a bidirectional device that relies on the user expiration. A new artificial mucus also coated the replica. Five parameters were varied to measure their influence on the powder deposition pattern in the olfactory region of the cast: the administration device, the instillation angle and side, the presence of a septum perforation, and the flow rate of possible concomitant inspiration. We found that the unidirectional powder device is more effective in targeting the olfactory zone than the bi-directional device. Also, aiming the spray nozzle directly at the olfactory area is more effective than targeting the center of the nasal valve. Moreover, the choice of the nostril and the presence of a perforation in the septum also significantly influence the olfactory deposition. On the contrary, the inspiratory flow has only a minor effect on the powder outcome. By selecting the more efficient administration device and parameters, 44% of the powder can reach the olfactory region of the nasal cast.</jats:p