Determination of the effective porosity of a single filter fiber

In this work, a numerical simulation of the aerosol motion when flowing around a single porous filter fiber with a diameter of 5 mm is carried out. The fiber is formed by a set of microfibers in a random arrangement. The size of the microfibers varies from 0.1 mm to 0.5 mm. For each fixed size of microfibers, a fiber model with different porosity of the medium was created. The porosity ranged from 0.7 to 0.9. The calculations were carried out in the ANSYS software package (v. 19.0). Studies have shown that a porous filter fiber model provides the maximum deposition efficiency for highly inert particles is provided by a porous filter fiber model with a microfiber size of 0.1 mm and a medium porosity of 0.9.

HEATING DEPTH OF GAS SUSPENSION FLOW BY COUNTER RADIATION

Выполнена аналитическая оценка отношения глубины прогрева газовзвеси излучением продуктов горения S к длине свободного пробега излучения в газовзвеси L. Использована одномерная модель стационарного распределения температуры в потоке взвешенных в воздухе монодисперсных инертных частиц, движущихся на равномерно нагретую абсолютно черную поверхность, имитирующую фронт пламени. Учитывается отражение и переизлучение тепловой энергии частицами. S / L >> 1 при низкой степени черноты и/или высокой конечной температуре частиц. It is accepted that the depth of heating of the gas suspension by the radiation of combustion products SR is equal to the length LR of the free path of radiation in the gas suspension: SR ≈ LR. Numerical simulation of gas-air mixture combustion with the addition of inert particles, taking into account the re-emission of heat by heated particles of fresh suspension, shows the possibility of realizing the ratio SR >> LR (Ivanov M.F. et al, 2015). In this work, an analytical estimate of the SR/LR ratio is carried out within the framework of one-dimensional modeling of the temperature distribution in the flow of initially cold monodisperse inert particles suspended in air, moving to a uniformly heated absolutely black surface, permeable to air suspension and simulating a flame front. The following assumptions are used. The solution is stationary in the coordinate system associated with the emitting surface; radiation consists of two oppositely directed streams of electromagnetic energy; the interaction of particles and radiation is described in the approximation of geometric optics and takes into account both the processes of absorption and emission of thermal energy, and the process of reflection of radiation; the temperature inside the particle is the same. In contrast to the previously considered (Poletaev N.L., 2021) the simplified problem of the motion of particles in a vacuum or in the presence of a gas phase heated by particles but not experiencing thermal expansion, this work took into account both the presence of a gas phase heated by particles and expansion of the gas phase. The latter causes the acceleration and expansion of the air suspension as it approaches the radiating surface. The difference in the local values of temperatures and phase motion velocities of the air suspension was neglected. It is shown that the quasi-linear (in the above-mentioned coordinate system) temperature distribution function in the air suspension obtained in this work is qualitatively different from the quasi-exponential temperature distribution function obtained earlier by solving a simplified problem. At the same time, the ratio of the heating depth of the air suspension by thermal radiation and the free path of radiation in the layer of air suspension adjacent to the radiating plane turned out to be similar to that obtained for the simplified solution. Namely, SR/LR >> 1 at a low integral degree of emissivity of the particle material and / or at a high final temperature of the particles, comparable to the temperature of the emitting surface.

Pulmonary Drug Delivery of Antimicrobials and Anticancer Drugs Using Solid Dispersions

It is well established that currently available inhaled drug formulations are associated with extremely low lung deposition. Currently available technologies alleviate this low deposition problem via mixing the drug with inert larger particles, such as lactose monohydrate. Those inert particles are retained in the inhalation device or impacted in the throat and swallowed, allowing the smaller drug particles to continue their journey towards the lungs. While this seems like a practical approach, in some formulations, the ratio between the carrier to drug particles can be as much as 30 to 1. This limitation becomes more critical when treating lung conditions that inherently require large doses of the drug, such as antibiotics and antivirals that treat lung infections and anticancer drugs. The focus of this work article is to review the recent advancements in carrier free technologies that are based on coamorphous solid dispersions and cocrystals that can improve flow properties, and help with delivering larger doses of the drug to the lungs.

Disharmony and the Final-Over-Final Condition in Amahuaca

The Final-Over-Final Condition (FOFC) rules out head-final projections that immediately dominate head-initial projections. Syntactically inert particles are known to show (apparent) exceptions to FOFC. However, Biberauer (2017) argues that seemingly FOFC-violating particles are compliant with a version of FOFC that is relativized to heads within an extended projection (Biberauer, Holmberg, and Roberts 2014). I present novel data from Amahuaca (Panoan; Peru) in which FOFC is violated by TAM particles within the verbal extended projection. I argue that this FOFC violation cannot be explained by the mechanisms proposed by Biberauer (2017). Instead, a view of FOFC grounded in restrictions on rightward dependencies (Cecchetto 2013; Zeijlstra 2016) predicts the type of exception found in Amahuaca.