Lattice Boltzmann simulations on the role of channel structure for reactive capillary infiltration

It is widely recognized that the structure of porous media is of relevance for a variety of mechanical and physical phenomena. The focus of the present work is on capillarity, a pore-scale process occurring at the micron scale. We attempt to characterize the influence of pore shape for capillary infiltration by means of Lattice Boltzmann simulations in 2D with reactive boundaries leading to surface growth and ultimately to pore closure. The systems under investigation consist of single channels with different simplified morphologies: namely, periodic profiles with sinusoidal, step-shaped and zig-zag walls, as well as constrictions and expansions with rectangular, convex and concave steps. This is a useful way to decompose the complexity of typical porous media into basic structures. The simulations show that the minimum radius alone fails to characterize properly the infiltration dynamics. The structure of the channels emerge as the dominant property controlling the process. A factor responsible for this behavior is identified as being the occurrence of pinning of the contact line. It turns out that the optimal configuration for the pore structure arises from the packing of large particles with round shapes. In this case, the probability to have flow paths wide and straight is higher. Faceted surfaces presenting sharp edges should be avoided because of the phenomenon of pinning near narrow-to-wide parts. This study is motivated by the infiltration of molten metals into carbon preforms. This is a manufacturing technique for ceramic components devised to advanced applications. Guidelines for experimental work are discussed.Comment: Publication: http://dx.doi.org/10.1080/19942060.2015.1026432 Material: https://sites.google.com/site/lbmodule/. Engineering Applications of Computational Fluid Mechanics (2015

Simulation of capillary infiltration into packing structures by the Lattice-Boltzmann method for the optimization of ceramic materials

In this work we want to simulate with the Lattice-Boltzmann method in 2D the capillary infiltration into porous structures obtained from the packing of particles. The experimental problem motivating our work is the densification of carbon preforms by reactive melt infiltration. The aim is to determine optimization principles for the manufacturing of high-performance ceramics. Simulations are performed for packings with varying structural properties. Our analysis suggests that the observed slow infiltrations can be ascribed to interface dynamics. Pinning represents the primary factor retarding fluid penetration. The mechanism responsible for this phenomenon is analyzed in detail. When surface growth is allowed, it is found that the phenomenon of pinning becomes stronger. Systems trying to reproduce typical experimental conditions are also investigated. It turns out that the standard for accurate simulations is challenging. The primary obstacle to overcome for enhanced accuracy seems to be the over-occurrence of pinning

Studying biological science does not lead to adoption of a healthy lifestyle

Aims: The lifestyle and physical activity (PA) habits of young people play a key role in the prevention of cardiovascular and metabolic diseases at older ages. The current generation of biological science students at university holds promise for better future medicine and medical technology. However, their physical fitness and lifestyle are often ignored. Methods: Lifestyle, PAs and common risk factors for cardiovascular disease before, and at, university were collected from 408 students using self-completed, anonymous surveys between the academic years of 2017 and 2019 from the School of Biological Sciences, University of Reading. Statistical analysis was performed using SAS® 9.4 software. Results: Among the 408 participants, 134 were male and 274 were female with a mean (SD) age of 19.6 (2.24). Approximately 19% of participants consumed alcohol beyond the safe limit of <14 units/week (112 g/week). Among them, 65% were males. Before university, 47% of students failed to meet the UK National Physical Activity Guidelines (NPAG) which increased to 56% during university with males exhibiting a steeper incline. Compared to their lifestyles before university, more students had insufficient sleep and displayed greater sedentariness during university. Moreover, 16% of students declared no engagement in PA which was greater than the value of 12% before university. Fitness perceptions worsened by 11% during university particularly for females. Statistical analysis revealed that gender, BMI and fitness perceptions were significantly correlated with PA levels. The most prevalent explanation for inadequacy in meeting NPAG was insufficient time. Conclusion: Compared to their pre-university lifestyles, biological science students at university are more likely to adopt unhealthier behaviours with less time for exercise and prolonged sedentary behaviours, which increases the risk for cardiovascular diseases. It is important to raise awareness of their fitness perceptions and to encourage health-promoting programmes at university

Facteurs Influençant la Progression du Score EDSS dans la Sclérose en Plaques Récurrente-Rémittente

Introduction : la Sclérose en plaques (SEP) est le prototype de désordre auto-immun du système nerveux central. Avec environ 110 malades par 100'000 habitants, la Suisse est considérée un pays à haute prévalence. Chez environ 80% des patients, la maladie débute par la forme récurrente- rémittente (RR), où des poussées aiguës s'intercalent avec des périodes de rémission. Cette phase se conclut dans son évolution naturelle généralement en une phase secondairement progressive, pendant laquelle le déficit progresse en l'absence de poussée. Sur le plan physiopathologique, deux phénomènes interagissent : l'atteinte inflammatoire démyélinisante et l'atteinte neurodégénerative. La première est { l'origine des poussées aiguës, la deuxième se manifeste cliniquement par la progression irréversible du déficit neurologique. En Suisse les immunomodulateurs ont été utilisés comme thérapies de fond pour la SEP à partir des années 1995. Leur effet sur le taux de poussées a été largement démontré, tandis que leur efficacité sur l'évolution de la maladie à long terme reste ouverte. Le moyen le plus répandu pour quantifier le niveau du handicap neurologique est la Kurtzke Expanded Disability Status Scale (EDSS). Cette échelle évalue les troubles neurologiques en les classifiant de 0 (examen normal) à 10 (décès) avec des marches de demi-points. Notre recherche à voulu identifier des facteurs cliniques précoces { valeur prédictif sur l'évolution du déficit neurologique permanent, ainsi qu'analyser le moment d'introduction du traitement pour extraire des informations utiles { la décision thérapeutique. Méthodes : Exploitation de la base de données iMed-CHUV comptant 1150 patients SEP (dont 622 SEP RR) pour analyser rétrospectivement, dans la SEP RR, l'influence de différentes variables cliniques précoces (taux de poussées pendant les premières deux années de maladie, intervalle entre les deux premières poussées, sévérité et site anatomique de la première poussée, déficit résiduel après la première poussée) et de deux caractéristiques liées { l'instauration du traitement immunosuppresseur de fond (âge et délai d'introduction) sur l'évolution du déficit neurologique vers un score EDSS ≥4.0. Les variables ont été testées avec la méthode d'estimation de taux de survie Kaplan-Meier. Résultats: 349 patients avec SEP RR possédaient les critères nécessaires pour faire partie de l'analyse, le suivi moyen étant de 8.26 ans (SD 4.77). Un taux de poussées élevé pendant les premiers 2 ans (&gt;1 vs ≤1) et un long intervalle entre les 2 premiers épisodes (&gt;36 vs &gt;12-36 vs ≤12) étaient significativement associés au risque de progression du déficit neurologique vers un score EDSS de 4.0 ou plus (log Rank P=0.016 et P=0.008 respectivement). Par contre ni le site anatomique de la première poussée ni l'âge d'introduction du traitement immunomodulateur n'avaient d'influence significative sur la progression du déficit neurologique (log rank P=0.370 et P=0.945 respectivement). Etonnamment une introduction rapide du traitement était associée à une plus forte progression du déficit neurologique (log rank P=0.032), montrant qu'une partie des patients a une évolution bénigne même en l'absence de traitement. Conclusions : L'activité inflammatoire précoce, dont le niveau peut être estimé par indices précoces comme le taux de poussées et l'intervalle entre les deux premières poussées, mais non le site de primo-manifestation prédit la progression ultérieure du déficit neurologique. Ces indices doivent être utilisés en combinaison avec les informations fournies par l'IRM pour l'individuation et le traitement précoce des patients à risque, indépendamment de leur âge. En raison des effets indésirables et des coûts élevés, les thérapies doivent cibler de façon spécifique les classes à risque, et épargner les patients avec évolution lente

Cuantificación de la huella hídrica del cultivo de arroz en dos zonas productoras de Perú. Arroz de riego en Perú competitivo e eficiente en el uso de agua mediante agricultura climáticamente inteligente

As the freshwater becomes a more essential and scarce resource, indicators have been arisen to measure water consumption. This has helped to warn about the use of this resource in different production sectors. Thus, several organizations have converged in a methodology for water footprint estimation. The water footprint is a sustainability indicator, which allows determining the agro-livestock impact on the environment. The impact assessment is carried out through the freshwater quantification used directly or indirectly in an agricultural production process. This study pretends to determine the water footprint for rice production in four different Peru's localities. The methodology was taken from the "The Water Footprint Assessment Manual", which sets the global standards for water consumption gauging. The study area is located in four Peruvian provinces, Utcumbamba, Chiclayo, Picota and Sullana. In all localities, two gauging stations were set up. These measured the total water used for rice irrigation during the whole crop cycle. At least one rice campaign was evaluated in each location. But, in places like Picota and Sullana suffered external inconveniences, which hampered the complete data capturing. For that reason, they only monitored the irrigation activities when the rice productive cycle was almost ending. Besides, weather and soil properties were also monitored. Weather data were taken through meteorological stations established in situ. The soil texture was measured at the field and then was used as input to obtain soil hydraulic characteristics. For this activity, the Soil Water Characteristics (SWC) software was implemented. From this initial phase, several findings were obtained, for example, in provinces such as Utcumbamba, it was able to assess the water consumption in irrigation that was 928.8 mm and 763.2 mm, for which almost 110 mm are irrigated before of planting. Likewise, farmers are used to employ high water quantities at the end of the cycle due to drought conditions. Finally, the project has just finished the gauging process, thus, it is expected that the water footprint can be assessed for these regions

Figuras de ancho constante: un tema por explorar

El objetivo de la ponencia es describir algunos métodos de construcción en el entorno Cabri Geometry II Plus que generan figuras de ancho constante; tales métodos son producto de un estudio sobre algunas propiedades y la historia de figuras con esta característica. Para el desarrollo de esta propuesta, presentamos específicamente un contexto que provee información sucinta de las propiedades básicas de estas figuras. Luego exponemos métodos de construcción que las generan y describimos los caminos que se utilizaron para poder deducirlos

Perancangan Cd Interaktif “What Makes You Beautiful” Ensiklopedia Kosmetik Interaktif Bagi Pemula

Kecantikan adalah identitas. Kecantikan merupakan sesuatu yang membuat wanita berbeda dari laki-laki. Kecantikan merupakan citra dari seorang wanita. Robert Jones (2011) mengungkapkan bahwa kebanyakan orang terobsesi dengan kecantikan dari luar (outward beauty), sampai-sampai mereka melupakan kecantikan dari dalam (inner beauty). Akan tetapi, sangat memungkinkan bahwa kecantikan dari luar merupakan cerminan hasrat seseorang untuk mengekspresikan kecantikan dari dalam diri-nya. Menurutnya, elemen paling penting dari kecantikan yang sesungguhnya adalah kepercayaan diri. Kepercayaan diri sendiri dapat ditimbulkan salah satunya dengan menonjolkan penampilan luar. Menurut Bobbi Brown (2011) wanita akan memperoleh kepercayaan diri yang lebih apabila mengerti tentang makeup, dengan memilih alat yang tepat, menemukan warna yang cocok untuknya dan menguasai teknik dasar dalam mengaplikasikannya. Artikel ini didasarkan pada Karya Tugas Akhir berjudul “Perancangan CD Interaktif ‘What Makes You Beautiful' Ensiklopedia Kosmetik Interaktif bagi Pemula” yang ditujukan untuk menjawab kebingungan/permasalahan wanita tentang bagaimana cara memilih kosmetik yang tepat untuk mempercantik dirinya dari luar ditengah maraknya peredaran berbagai jenis kosmetik di pasaran

Robot Composite Learning and the Nunchaku Flipping Challenge

Advanced motor skills are essential for robots to physically coexist with humans. Much research on robot dynamics and control has achieved success on hyper robot motor capabilities, but mostly through heavily case-specific engineering. Meanwhile, in terms of robot acquiring skills in a ubiquitous manner, robot learning from human demonstration (LfD) has achieved great progress, but still has limitations handling dynamic skills and compound actions. In this paper, we present a composite learning scheme which goes beyond LfD and integrates robot learning from human definition, demonstration, and evaluation. The method tackles advanced motor skills that require dynamic time-critical maneuver, complex contact control, and handling partly soft partly rigid objects. We also introduce the "nunchaku flipping challenge", an extreme test that puts hard requirements to all these three aspects. Continued from our previous presentations, this paper introduces the latest update of the composite learning scheme and the physical success of the nunchaku flipping challenge

El proyecto de vida de tres adolescentes, afectados por el conflicto armado en Colombia

206 Páginas.Se realizó un estudio de caso comparado, sobre los diferentes factores que inciden en el proyecto de vida de tres adolescentes afectados por el conflicto armado en Colombia se describió la historia de cada uno y la auto percepción en relación con su proyecto de vida. Dos están vinculados a la Fiscalía General de la Nación, la tercera cursa estudios en la Universidad Piloto de Colombia. Se realizaron entrevistas a profundidad, con relación a la afectación del proyecto de vida, fueron analizadas mediante la triangulación, a fin de sugerir recomendaciones a las dos instituciones, buscando optimizar la atención, a partir de una formación basada en hábitos y resolución de conflictos, favoreciendo la elaboración del proyecto de vida de estos adolescentes. Nota: Para consultar la carta de autorización de publicación de este documento por favor copie y pegue el siguiente enlace en su navegador de Internet: http://hdl.handle.net/10818/894