Validation and calibration of coupled porous-medium and free-flow problems using pore-scale resolved models

The correct choice of interface conditions and effective parameters for coupled macroscale free-flow and porous-medium models is crucial for a complete mathematical description of the problem under consideration and for accurate numerical simulation of applications. We consider single-fluid-phase systems described by the Stokes-Darcy model. Different sets of coupling conditions for this model are available. However, the choice of these conditions and effective model parameters is often arbitrary. We use large scale lattice Boltzmann simulations to validate coupling conditions by comparison of the macroscale simulations against pore-scale resolved models. We analyse two settings (lid driven cavity over a porous bed and infiltration problem) with different geometrical configurations (channelised and staggered distributions of solid grains) and different sets of interface conditions. Effective parameters for the macroscale models are computed numerically for each geometrical configuration. Numerical simulation results demonstrate the sensitivity of the coupled Stokes-Darcy problem to the location of the sharp fluid-porous interface, the effective model parameters and the interface conditions

Influence of digital technologies of distance education on the mental health of a child in the conditions of wartime realities

Russian aggression against Ukraine has caused considerable damage not only to the Ukrainian economy and infrastructure but also to the mental health of the nation. The highest risk group includes schoolchildren who have experienced traumatic experiences and, in some cases, physical injuries. The purpose of the article is to analyze the impact of digital technologies of distance education on the mental health of children in the conditions of military operations. Methods of analysis, synthesis, structural-functional, prognostic were used. In the results, the general problems of children's mental health formation in Ukraine were determined, peculiarities of the implementation of the recommendations of the World Health Organization regarding the observance of mental health were traced, and the effects of an aggressive digital environment, which were intensified by military actions, were determined. Special attention is paid to the recommendations to teachers regarding the continued use of digital technologies and distance education in wartime conditions. In the conclusions, it was noted that military challenges impose additional obligations on teachers and parents, because in the conditions of martial law, protecting children's psyche from additional stress is extremely important. For this, a system of methodological recommendations has been developed, which will be relevant for this process

Prospective randomized controlled pilot study on the effects of almond consumption on skin lipids and wrinkles.

ObjectiveAlmonds are a rich source of fatty acids and antioxidants, and their supplementation is known to significantly modulate serum lipids. The effects of almond on the skin's lipid barrier and the appearance of wrinkles have not yet been elucidated. The aim of this study was to investigate the effects of almond consumption on facial sebum production and wrinkles.MethodsThis was a prospective, investigator-blinded, randomized controlled trial in which subjects consumed 20% of their daily energy consumption in either almonds or a calorie-matched snack for 16 weeks. This study was completed at the UC Davis Dermatology clinic. Participants were a volunteer sample of generally healthy postmenopausal females with Fitzpatrick skin types 1 and 2. A facial photograph and image analysis system was used to obtain standardized photographs and information on wrinkle width and severity at 0, 8, and 16 weeks. Measurements of transepidermal water loss and sebum production were also completed at 0, 8, and 16 weeks.ResultsFifty healthy postmenopausal females were recruited, 31 participants were enrolled, and 28 completed the study. Under photographic analysis, the almond group had significantly decreased wrinkle severity and width compared with the control group at 16 weeks (p < .02). Changes in skin barrier function were nonsignificant, measured by the transepidermal water loss (p = .65) between the almond and control groups relative to baseline after 16 weeks. No adverse effects were reported.ConclusionOur study demonstrates that daily almond consumption may reduce wrinkle severity in postmenopausal females to potentially have natural antiaging benefits

Uncertainty-aware Validation Benchmarks for Coupling Free Flow and Porous-Medium Flow

A correct choice of interface conditions and useful model parameters for coupled free-flow and porous-medium systems is vital for physically consistent modeling and accurate numerical simulations of applications. We consider the Stokes--Darcy problem with different models for the porous-medium compartment and corresponding coupling strategies: the standard averaged model based on Darcy's law with classical or generalized interface conditions, as well as the pore-network model. We study the coupled flow problems' behaviors considering a benchmark case where a pore-scale resolved model provides the reference solution and quantify the uncertainties in the models' parameters and the reference data. To achieve this, we apply a statistical framework that incorporates a probabilistic modeling technique using a fully Bayesian approach. A Bayesian perspective on a validation task yields an optimal bias-variance trade-off against the reference data. It provides an integrative metric for model validation that incorporates parameter and conceptual uncertainty. Additionally, a model reduction technique, namely Bayesian Sparse Polynomial Chaos Expansion, is employed to accelerate the calibration and validation processes for computationally demanding Stokes--Darcy models with different coupling strategies. We perform uncertainty-aware validation, demonstrate each model's predictive capabilities, and make a model comparison using a Bayesian validation metric

The use of topical Nitrosomonas eutropha for cosmetic improvement of facial wrinkles

BackgroundBoth topical and oral probiotics are becoming widely used. There is increasing interest in the cosmetic potential in topical probiotics. Nitrosomonas eutropha is an ammoniaâ oxidizing bacteria.AimThe purpose of this study was to assess whether there is any improvement in facial wrinkles with the use of Nitrosomonas eutropha, a topical probiotic.MethodsIn this prospective study, highâ resolution photographs were obtained in twentyâ nine participants at baseline and after using topical Nitrosomonas eutropha for seven days.ResultsThere was a significant difference in wrinkle depth and severity in the high concentration probiotic group. There was also a statistically significant improvement in pigmentation of the forehead and glabella in the higher concentration group.ConclusionsNitrosomonas eutropha may have aesthetic benefits in terms of reducing the appearance of wrinkles. Larger studies with longer treatment and followâ up periods are required.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154401/1/jocd13060_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154401/2/jocd13060.pd

Mathematische Modellierung gekoppelter Systeme von freien Strömungen und porösen Medien

Different classes of physical systems with common interfaces arise in a variety of environmental and industrial problems. Striking examples originate from terrestrial-atmospheric contact zones, surface water-groundwater interaction, filters and fuel cells, where a free fluid system is in contact with a porous medium. Flow and transport processes in these systems evolve on multiple length and time scales, contributing to the complexity of these systems both from the modeling and the numerical side. An additional contributing factor to this complexity is the existence of multiple classes of entities, which include phases, interfaces between phases, and common curves that form at the boundary between three phases. Classical coupling approaches and traditional porous medium model formulations lead to reliable results in limited cases, however, applications require more realistic settings. The focus of the thesis is on derivation of mathematical models for multiphase multi-component porous medium systems that take into account lower dimensional entities, formulation of coupling conditions at the sharp interface and the transition region between porous medium and free flow systems, computation of effective parameters for the macroscale models, development and analysis of efficient numerical algorithms for coupled problems, and numerical simulation of applications.Bei vielen Problemen der Natur- und Ingenieurwissenschaften trifft man auf Übergänge zwischen verschiedenen physikalischen Systemen. Beispiele umfassen terrestrisch-atmosphärische Kontaktzonen, Wechselwirkungen zwischen Oberflächenwasser und Grundwasser, Filter und Brennstoffzellen, wobei ein freies Fluidsystem mit einem porösen Medium in Kontakt steht. Physikalische Prozesse in diesen beiden Strömungssystemen laufen auf verschiedenen Längen- und Zeitskalen ab, was das Zusammenspiel beider Systeme, sowohl unter Modellierungs- als auch unter numerischen Gesichtspunkten, sehr komplex macht. Ein zusätzlicher Faktor, der die Komplexität erhöht, ist die Existenz mehrerer Phasen und damit von Phasengrenzflächen und Kontaktlinien, also Kurven, die die Grenze zwischen drei Phasen beschreiben. Klassische Kopplungskonzepte und traditionelle Modelle von porösen Medien führen zwar in eingeschränkten Fällen zu verlässlichen Ergebnissen, jedoch erfordern Anwendungen realistischere Herangehensweisen. Der Fokus der vorliegenden Arbeit liegt auf der Entwicklung von mathematischen Modellen für Mehrphasen-Mehrkomponenten-Systeme poröser Medien unter Berücksichtigung von Komponenten niedrigerer Dimension, der Formulierung von Kopplungsbedingungen am Übergang zwischen porösem Medium und freier Strömung, der Entwicklung von effizienten numerischen Algorithmen für gekoppelte Probleme und deren Analysis, der numerischen Simulation von Anwendungen und der Berechnung von effektiven Parametern für die Makroskalenmodelle

Validation and calibration of coupled porous-medium and free-flow problems using pore-scale resolved models

The correct choice of interface conditions and effective parameters for coupled macroscale free-flow and porous-medium models is crucial for a complete mathematical description of the problem under consideration and for accurate numerical simulation of applications. We consider single-fluid-phase systems described by the Stokes–Darcy model. Different sets of coupling conditions for this model are available. However, the choice of these conditions and effective model parameters is often arbitrary. We use large-scale lattice Boltzmann simulations to validate coupling conditions by comparison of the macroscale simulations against pore-scale resolved models. We analyse three settings (lid-driven cavity over a porous bed, infiltration problem and general filtration problem) with different geometrical configurations (channelised and staggered distributions of solid grains) and different sets of interface conditions. Effective parameters for the macroscale models (permeability tensor, boundary layer constants) are computed numerically for each geometrical configuration. Numerical simulation results demonstrate the sensitivity of the coupled Stokes–Darcy problem to the location of the sharp fluid–porous interface, the effective model parameters and the interface conditions.Bundesministerium für Bildung und Forschung https://doi.org/10.13039/501100002347Deutsche Forschungsgemeinschaft (DE)Deutsche Forschungsgemeinschaft (DE)Bundesministerium für Bildung und Forschung (DE