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Статті в журналах з теми "Active Granular Systems"
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Miao, Guoqing, Kai Huang, Yi Yun, and Rongjue Wei. "Active thermal convection in vibrofluidized granular systems." European Physical Journal B 40, no. 3 (September 2004): 301–4. http://dx.doi.org/10.1140/epjb/e2004-00277-7.
Повний текст джерела
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Morse, Peter K., Sudeshna Roy, Elisabeth Agoritsas, Ethan Stanifer, Eric I. Corwin, and M. Lisa Manning. "A direct link between active matter and sheared granular systems." Proceedings of the National Academy of Sciences 118, no. 18 (April 30, 2021): e2019909118. http://dx.doi.org/10.1073/pnas.2019909118.
Повний текст джерелаАнотація:
The similarity in mechanical properties of dense active matter and sheared amorphous solids has been noted in recent years without a rigorous examination of the underlying mechanism. We develop a mean-field model that predicts that their critical behavior—as measured by their avalanche statistics—should be equivalent in infinite dimensions up to a rescaling factor that depends on the correlation length of the applied field. We test these predictions in two dimensions using a numerical protocol, termed “athermal quasistatic random displacement,” and find that these mean-field predictions are surprisingly accurate in low dimensions. We identify a general class of perturbations that smoothly interpolates between the uncorrelated localized forces that occur in the high-persistence limit of dense active matter and system-spanning correlated displacements that occur under applied shear. These results suggest a universal framework for predicting flow, deformation, and failure in active and sheared disordered materials.
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Williams, K. J., S. J. Tait, and R. M. Ashley. "In-sewer sedimentation associated with active flow control." Water Science and Technology 60, no. 1 (July 1, 2009): 55–63. http://dx.doi.org/10.2166/wst.2009.286.
Повний текст джерелаАнотація:
Active flow control using automated gates and weirs aims to utilise available dispersed storage within sewer systems to alleviate the severity and frequency of localised flooding incidents. Whilst a previous study has demonstrated its potential, a key operational concern before implementation was sedimentation. An experimental programme was designed to investigate the sediment deposition created when using a flow control device. Tests were also undertaken to examine the potential for rapid gate opening to flush away any resulting deposits. In catchments dominated by fine material in suspension, the use of an active flow control device can result in a uniformly thick deposit upstream of the gate. Rapid gate opening results in deposited material eroding in large sections starting at the gate and moving in an upstream direction. Granular sediment forms a series of discrete bedforms which are fairly uniform regardless of the flow conditions and a larger deposit further upstream. The potential for flushing granular deposits is limited and modification of the operation of the gate has shown little potential for increasing the effectiveness. Therefore, active flow control using a single downstream gate may only be suitable in systems with fine material moving in suspension during dry weather flow and not where there is significant granular sediment.
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Bérut, Antoine, Hugo Chauvet, Valérie Legué, Bruno Moulia, Olivier Pouliquen, and Yoël Forterre. "Gravisensors in plant cells behave like an active granular liquid." Proceedings of the National Academy of Sciences 115, no. 20 (April 30, 2018): 5123–28. http://dx.doi.org/10.1073/pnas.1801895115.
Повний текст джерелаАнотація:
Plants are able to sense and respond to minute tilt from the vertical direction of the gravity, which is key to maintain their upright posture during development. However, gravisensing in plants relies on a peculiar sensor made of microsize starch-filled grains (statoliths) that sediment and form tiny granular piles at the bottom of the cell. How such a sensor can detect inclination is unclear, as granular materials like sand are known to display flow threshold and finite avalanche angle due to friction and interparticle jamming. Here, we address this issue by combining direct visualization of statolith avalanches in plant cells and experiments in biomimetic cells made of microfluidic cavities filled with a suspension of heavy Brownian particles. We show that, despite their granular nature, statoliths move and respond to the weakest angle, as a liquid clinometer would do. Comparison between the biological and biomimetic systems reveals that this liquid-like behavior comes from the cell activity, which agitates statoliths with an apparent temperature one order of magnitude larger than actual temperature. Our results shed light on the key role of active fluctuations of statoliths for explaining the remarkable sensitivity of plants to inclination. Our study also provides support to a recent scenario of gravity perception in plants, by bridging the active granular rheology of statoliths at the microscopic level to the macroscopic gravitropic response of the plant.
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Schreiber, Marvin M., Michael V. Hickman, and Gordon D. Vail. "Efficacy of Starch-Encapsulated Formulations of Atrazine Containing Two or Three Herbicides in Same Granule." Weed Technology 8, no. 1 (March 1994): 105–13. http://dx.doi.org/10.1017/s0890037x00039282.
Повний текст джерелаАнотація:
Field experiments were conducted in 1990, 1991, and 1992 to evaluate and compare the efficacy of commercial herbicide formulations with starch encapsulated granules that contain one, two, or three herbicides. Atrazine in combination with alachlor or metolachlor composed the two-component granules and the addition of dicamba to both composed the three-component granules. All starch-encapsulated formulations were produced by twin screw extrusion technology and evaluated in two granule sizes, 1.4 to 0.5-mm (14 to 20 mesh) and 0.85 to 0.43-mm (20 to 40 mesh). Active ingredient rates applied were selected for the existing soil conditions and combination granules contained active ingredients proportional to premixed commercial formulations available or suggested for tank mixes. Evaluations were performed under conventional, chisel, and no-tillage systems. PRE and PPI applications of starch encapsulated two-component (atrazine-alachlor) in 1990 controlled giant foxtail (except at the low rate with large granule size), redroot pigweed, and common lambsquarters excellently but control of velvetleaf was fair to poor. Smaller-sized granules were generally more effective for controlling weeds than the larger-sized granules. In 1991, starch-encapsulated two-component (atrazine-metolachlor) granules applied both PRE and PPI in conventional, chisel, and no-till systems gave results similar to 1990 with the small granules more effective on velvetleaf. The addition of dicamba in the granule to form three-component starch-encapsulated granules in 1992 resulted in control of velvetleaf, ivyleaf morningglory, and jimsonweed statistically equal to commercial formulations except in one case of no-till corn. In our experiments, herbicide formulations (granular vs. commercial) had no significant effect on corn yield in 28 out of 31 treatments. These data indicate that if the experimental three-component starch-encapsulated formulations of corn herbicides used in these studies were optimized they could become as efficacious as commercial formulations presently on the market. This is the first report of research containing data on two- and three-component starch-encapsulated granular formulations.
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Li, Shengkai, Bahnisikha Dutta, Sarah Cannon, Joshua J. Daymude, Ram Avinery, Enes Aydin, Andréa W. Richa, Daniel I. Goldman, and Dana Randall. "Programming active cohesive granular matter with mechanically induced phase changes." Science Advances 7, no. 17 (April 2021): eabe8494. http://dx.doi.org/10.1126/sciadv.abe8494.
Повний текст джерелаАнотація:
At the macroscale, controlling robotic swarms typically uses substantial memory, processing power, and coordination unavailable at the microscale, e.g., for colloidal robots, which could be useful for fighting disease, fabricating intelligent textiles, and designing nanocomputers. To develop principles that can leverage physical interactions and thus be used across scales, we take a two-pronged approach: a theoretical abstraction of self-organizing particle systems and an experimental robot system of active cohesive granular matter that intentionally lacks digital electronic computation and communication, using minimal (or no) sensing and control. As predicted by theory, as interparticle attraction increases, the collective transitions from dispersed to a compact phase. When aggregated, the collective can transport non-robot “impurities,” thus performing an emergent task driven by the physics underlying the transition. These results reveal a fruitful interplay between algorithm design and active matter robophysics that can result in principles for programming collectives without the need for complex algorithms or capabilities.
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Khomenko, Andrei P., Sergey K. Kargapoltsev, and Andrey V. Eliseev. "Development of Approaches to Creation of Active Vibration Control System in Problems of the Dynamics for Granular Media." MATEC Web of Conferences 148 (2018): 11004. http://dx.doi.org/10.1051/matecconf/201814811004.
Повний текст джерелаАнотація:
The article deals with the development of mathematical models and evaluation criteria of the vibration field in the dynamic interactions of the elements of the vibrational technological machines for the processes of vibrational strengthening of long-length parts with help of a steel balls working medium. The study forms a theoretical understanding of the modes of motions of material particles in interaction with a vibrating surface of the working body of the vibration machine. The generalized approach to the assessment of the dynamic quality of the work of vibrating machines in multiple modes of tossing, when the period of free flight of particles is a multiple of the period of the surface oscillations of the working body, is developed in the article. For the correction of vibration field of the working body, the characteristics of dynamic interactions of granular elements of the medium are taken into account using original sensors. The sensors that can detect different particularities of interaction of the granular medium elements at different points of the working body are proposed to evaluate the deviation from a homogeneous and one-dimensional mode of vibration field. Specially developed sensors are able to register interactions between a single granule, a system of granules in filamentous structures, and multipoint interactions of the elements in a close-spaced cylindrical structure. The system of regularization of the structure of vibration fields based on the introduction of motion translation devices is proposed using the multi-point sensor locations on the working body. The article refers to analytical approaches of the theory of vibration displacements. For the experimental data assessment, the methods of statistical analysis are applied. It is shown that the peculiar features of the motion of granular medium registered by the sensors can be used to build active control systems of field vibration.
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Nadeina, Ksenia A., Sergey V. Budukva, Yuliya V. Vatutina, Polina P. Mukhacheva, Evgeniy Yu Gerasimov, Vera P. Pakharukova, Oleg V. Klimov, and Aleksandr S. Noskov. "Unsupported Ni—Mo—W Hydrotreating Catalyst: Influence of the Atomic Ratio of Active Metals on the HDS and HDN Activity." Catalysts 12, no. 12 (December 19, 2022): 1671. http://dx.doi.org/10.3390/catal12121671.
Повний текст джерелаАнотація:
Hydrotreating is one of the largest processes used in a refinery to improve the quality of oil products. The great demand of the present is to develop more active catalysts which could improve the energy efficiency of the process when it is necessary for heavier feedstock to be processed. Unsupported catalysts could solve this problem, because they contain the greatest amount of sulfide active sites, which significantly increase catalysts’ activity. Unfortunately, most of the information on the preparation and properties of unsupported catalysts is devoted to powder systems, while industrial plants require granular catalysts. Therefore, the present work describes a method for the preparation of granular Ni—Mo—W unsupported hydrotreating catalysts and studies the influence of the Ni/Mo/W atomic ratio on their properties. Catalysts have been prepared by plasticizing Ni—Mo—W precursor with aluminum hydroxide followed by granulation and drying stages. Ni—Mo—W precursor and granular catalysts were studied by X-ray diffraction (XRD), nitrogen adsorption–desorption method, high-resolution transmission electron microscopy (HRTEM), and thermal analysis. Granular catalysts were sulfided through a liquid-phase sulfidation procedure and tested in hydrotreating of straight-run vacuum gasoil. It was shown that the Ni/Mo/W atomic ratio influenced the formation and composition of active compounds and had almost no influence on the textural properties of catalysts. The best hydrodesulfurization (HDS) activity was obtained for the catalyst with Ni/Mo/W ratio—1/0.15/0.85, while hydrodenitrogenation (HDN) activity of the catalysts is very similar.
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Duan, Hai Xia, and Jia Hui Qu. "Study on Synergetic Catalytic Ozonation of Nitrobenzene in Nebulizing Systems." Advanced Materials Research 243-249 (May 2011): 5304–7. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.5304.
Повний текст джерелаАнотація:
The removal effect of nitrobenzene (NB) in water by VUV/O3/GAC synergetic catalyzing method in a nebulizing system was studied. In addition, the effects of the droplet size, the nebulization height, O3 flux, free radical scavengers and active carbon usage frequencies on the degradation of NB were investigated. In this study, a spray nozzle that could produce 10-micrometer droplets were adopted, a UV lamp that emitted 185nm VUV light was used as the light source and a layer of 0.5cm granular active carbon was laid at the bottom of the experimental apparatus. The results showed that, in the apparatus, when the NB concentration in deionized water was 200mg/L, the nebulization height was 1.3m, O3 flux was 150mg/L, the removal rate of NB reached 95.3%. Supercarbonate acted as a catalyst in the system.
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Ismail, S. B., P. Gonzalez, D. Jeison, and J. B. van Lier. "Effects of high salinity wastewater on methanogenic sludge bed systems." Water Science and Technology 58, no. 10 (November 1, 2008): 1963–70. http://dx.doi.org/10.2166/wst.2008.528.
Повний текст джерелаАнотація:
The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge. Sodium concentration of 5 g/L and 15 g/L were added to the influent of upflow anaerobic sludge bed (UASB) systems. After 100 days of operation, the methanogenic activity, extracellular polymeric substances (EPS), and granular strength were analyzed. The results show a high removal of organic matter but with accumulating propionate concentrations in the effluents. Meanwhile, wash-out of active methanogenic biomass in the effluent of the reactors was observed, likely as a results of the high Na+ concentrations. The rinsed biomass was characterized by a considerable specific methanogenic activity (SMA) on acetate, propionate and hydrogen as the substrates. On the other hand, results show that the SMA evolution was not affected by high salt concentrations. Also the amount and composition of extracellular polymeric substances (EPS) were similar in all sludges. However, results clearly show a sharp drop in the granule strength as a results of high Na+ concentration.
Дисертації з теми "Active Granular Systems"
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Velghe, Carine. "Oral controlled drug delivery systems, optimization of release patterns and elucidation of release mechanisms." Thesis, Lille 2, 2013. http://www.theses.fr/2013LIL2S048/document.
Повний текст джерелаАнотація:
Le développement de nouvelles formes galéniques nécessite la mise au point de protocoles avec variation d’un ensemble de paramètres jouant sur les caractéristiques du dispositif. Au niveau industriel, cela représente une perte importante de temps et d’argent. Avec le développement d’outils permettant la caractérisation des systèmes et à fortiori des mécanismes impliqués dans la libération du principe actif, l’application des modèles mathématiques se voit être de plus en plus grande permettant de prédire la sortie du principe actif hors de son système. L’un des objectifs de ce travail a été de développer un modèle mathématique mécanique réaliste permettant de quantifier la libération de vitamines à partir de matrice lipidique. Deux techniques différentes de formulation : la compression directe et une suite d’extrusion en phase chauffante/ broyage/ compression directe ont permis la préparation de comprimés à base de Compritol 888 (glyceryl dibehenate NF). L’acide nicotinique a été utilisé comme principe actif modèle hautement soluble dans le milieu environnant. Des études de dissolution ont montrée une libération plus accrue pour des comprimés ayant une charge initiale en vitamine plus importante, cela liée à une augmentation de la porosité de la matrice avec l’épuisement graduel de la vitamine. Concernant la technique de préparation, un taux de sortie beaucoup plus faible dans le cas des comprimés préparés par extrusion en phase chauffante préalable, est mesuré, dû à un emprisonnement de la vitamine par la matrice fondue. A partir de ces observations et des connaissances sur les matrices lipidiques, un modèle basé sur les lois de diffusion de Fick et sur la considération de la coexistence d’une partie du principe actif sous forme dissoute ou non dissoute a été élaboré. Ce modèle permet la prédiction de la quantité de vitamine libérée au cours du temps en fonction de l’impact de la composition, de la technique de préparation et de la taille du système. Ces simulations in-silico sont d’une grande aide pour permettre d’accélérer la production de comprimés à base de Compritol 888. Dans le cas de systèmes multiparticulaires, et encore plus dans le cas de formes enrobées, des modèles mathématiques peuvent également être établis mais montrent une complexité plus grande, notamment due à la membrane polymérique. Dans cette optique, le développement de nouveaux outils pour caractériser les systèmes est primordial. Dernièrement la technologie Terahertz voit son potentiel comme nouvel outil dans la caractérisation de systèmes enrobés croissant. Son emploi dans la détection de différence de taille et d’uniformité de films polymériques d’enrobage pour des systèmes multicouches a été réalisé sur des granules de tailles conventionnelles (1mm de diamètre). Un premier enrobage de metoprolol succinate a été réalisé sur des noyaux de sucre, suivi d’un enrobage permettant le contrôle de la fuite du principe actif à base d’un mélange de Kollicoat SR :Kollicoat IR. Des granules avec différentes tailles d’enrobage ont été étudiées par Terahertz. Une taille homogène de la couche de principe actif pulvérisée a été montré dans tous les types de pellets ; alors qu’une taille croissante de l’enrobage polymérique 46 µm, 71 µm et 114 µm a pu être appréhendée. Ces résultats, mis en corrélation avec les méthodes de dissolution traditionnelles, permettront le développement d’une formule prédisant les cinétiques de libération à partir de la lecture non destructive de l’épaisseur d’enrobage par Térahertz.[...]Development of new galenic devices needs series experiments with variation of number parameters. For industrial, it’s a lost in time and money. Food and Drug Administration initiated since several years, Process Analytical Technology (PAT) as a tool to analyze and control pharmaceutical process. These tools can be helpful to determine drug release mechanism and allow application of mathematical model to predict drug release kinetics. One objective of this work is to develop a mechanistically realistic mathematical model allowing for the quantification of vitamin release from Compritol 888 (glyceryl dibehenate NF)-based matrix tablets, prepared either by direct compression or via hot-melt extrusion/grinding/compression. Nicotinic acid has been used as highly soluble drug in surrounding medium. Dissolution studies show vitamin release rates increased with increasing initial niacin content, due to the increased matrix porosity upon vitamin depletion. In all cases, niacin release from tablets prepared via hot-melt extrusion was slower than from tablets prepared by direct compression, due to more intense embedding of the vitamin within the lipid. Importantly, a numerical model based on Fick’s law of diffusion and considering the co-existence of dissolved and non-dissolved vitamin could successfully be used to quantify vitamin release from both types of tablets, irrespective of the initial niacin loading and tablet size. In-silico simulations can be very helpful to accelerate product optimization of Compritol 888-based matrices, saving development time and costs. For multiparticulates systems, and more again for coated forms, mathematical models are more complexes. In this goal, development of new tools to characterize devices is primordial. Technology Terahertz offers an interesting potential. This technique can be used to detect difference in size and uniformity for polymeric film from multilayer pellets of 1 mm diameter. Pellets consisting of a sugar starter core and a metoprolol succinate layer were coated with a Kollicoat® SR: Kollicoat® IR polymer blend. Pellets with several coating thickness are studied. No drug layer thickness difference between batches was observed, and the average coating thicknesses were 46 µm, 71 µm and 114 µm, for the different batches. Terahertz results compared with experimental data from dissolution methods, allow predicting coating thickness results correlated with the subsequent drug release behavior. Multiparticulates systems have important interest: they allow avoiding “dose dumping”. Dose dumping is described as an unintended, rapid drug release in a short period of time of the entire amount or a significant fraction of the drug contained in a modified release dosage form (Meyer, 2005). This phenomenon can be observed in the case of ethylcellulose-based devices in presence with ethanol rich-media. Recently, ethylcellulose:guar gum blend have been reported to provide ethanol-resistant drug release kinetics from coated dosage forms. Theophylline matrix pellets were coated with ethylcellulose: guar gum blends. These granules show no change in drug release profiles upon contact with medium containing 40% of ethanol (v/v). This is because the ethanol insoluble guar gum effectively avoids undesired ethylcellulose dissolution in ethanol-rich bulk fluids. However, so far the importance of crucial formulation parameters, including the minimum amount of guar gum to be incorporated and the minimum required guar gum viscosity, remains unclear. It was found that more than 5% guar gum (referred to the total polymer content) must be incorporated in the film coating and that the apparent viscosity of a 1% aqueous guar gum solution must be greater than 150 cPs to provide ethanol-resistance. [...]
Книги з теми "Active Granular Systems"
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Terentjev, Eugene M., and David A. Weitz, eds. The Oxford Handbook of Soft Condensed Matter. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199667925.001.0001.
Повний текст джерелаАнотація:
This Handbook serves both as an introduction and an overview of the field of soft condensed matter. The discussion covers topics ranging from the fundamentals of colloid science to the principles and action of surfactants, modern directions of research in liquid crystals, and the key properties of foams. The book also explores the fundamental physics that controls the structure and mechanics of granular matter; how the unusual and often dramatic mechanical properties of concentrated polymer systems are determined by the physics of entanglements; the complex structures formed by block copolymers and the methods of structure analysis; rubber elasticity and new emerging classes of rubber-elastic materials; the physics of polyelectrolytes; the solvent dynamics in polymer gels, in equilibrium and under mechanical stress; the hierarchical structure and characteristics of an extracellular matrix; and the hierarchical structure and resulting physical properties of the cell cytoskeleton. The book concludes with an analysis of the properties of interfaces and membranes.
Частини книг з теми "Active Granular Systems"
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Goss, G. Robert, Y. Bernal, A. Johnsonbaugh, and R. Henderson. "Granular Formulations and Active Ingredient Distribution from a Rotary Spreader." In Pesticide Formulations and Delivery Systems, 30th Volume: Regulations and Innovation, 35–42. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2010. http://dx.doi.org/10.1520/stp152720120003.
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Ben Dor, Ydan, Yariv Kafri, and Julien Tailleur. "Forces in Dry Active Matter." In Active Matter and Nonequilibrium Statistical Physics, 591–621. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192858313.003.0016.
Повний текст джерелаАнотація:
Abstract This chapter introduces recent developments in the thermomechanics of active systems, which exhibit features that are very different from those of equilibrium systems. This has many implications for systems ranging from shaken granular gases to the motion of cells. We start with a short overview of different definitions of pressure and the conditions under which they are equivalent. This allows us to identify a class of systems – commonly referred to as dry active matter – where the simple equilibrium intuition might break. We show that there is, in general, no equation of state for the forces they exert on their container. We discuss the origin of this phenomenon, as well as its consequences. Finally, we go beyond the question of the equation of state and provide a brief discussion of recent developments concerning the forces exerted on objects immersed in active systems.
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Carloni, Giovanna. "Online language teacher education and active learning through CALL and ICALL." In Intelligent CALL, granular systems and learner data: short papers from EUROCALL 2022, 36–40. Research-publishing.net, 2022. http://dx.doi.org/10.14705/rpnet.2022.61.1431.
Повний текст джерелаАнотація:
This essay illustrates how an online language education course, implemented within an online language teacher education programme offered at master’s level at an Italian university, was designed to foster pre-service teachers’ active learning through digitally-enhanced activities. The course was developed within a community of inquiry framework and from a socio-constructivist perspective. The online course adopted a flipped learning approach. Pre-service teachers carried out asynchronous digitally-enhanced activities individually and collaboratively before class and synchronous technology-enhanced collaborative activities during live classes. Pre-service teachers thus engaged in active learning throughout the course.
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Hollenstein, Nora, and Mircea F. Lungu. "Analyzing user interactions to estimate reading time in web-based L2 reader applications." In Intelligent CALL, granular systems and learner data: short papers from EUROCALL 2022, 168–73. Research-publishing.net, 2022. http://dx.doi.org/10.14705/rpnet.2022.61.1453.
Повний текст джерелаАнотація:
We propose to use reading time as a metric to report progress in language learning applications. As a case study we use a web-based application that enables learners of a foreign language to read texts from the web and practice vocabulary with interactive exercises generated based on their past readings. The application captures generic interactions with the web page (e.g. switching to a different tab) but also interactions directly related to language learning (e.g. clicking on a word to get a translation). We propose two metrics for approximating reading times based on user interactions with the web application. We analyze the correlation between these metrics and other interaction metrics and show that active time is the best metric for estimating the user’s actual involvement with the texts and that it can be approximated from interaction metrics.
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Rankey, Eugene C. "Deep‐Time Perspectives on Miocene Isolated Carbonate Platforms of Southeast Asia." In Cenozoic Isolated Carbonate Platforms—Focus Southeast Asia, 5–31. SEPM (Society for Sedimentary Geology), 2023. http://dx.doi.org/10.2110/sepmsp.114.01.
Повний текст джерелаАнотація:
Although the biota, facies, stacking patterns, sequence stratigraphy, and diagenesis of numerous isolated carbonate platforms have been described and interpreted, trends in the genesis, evolution, and sizes among Phanerozoic examples remain poorly quantified. To provide broad perspectives on Miocene isolated platforms of Central Luconia and Southeast Asia (the focus of this volume), this study summarizes the results of qualitative review of the literature and a quantitative analysis of a relational database of attributes in initiation, growth, character, and demise of more than 850 Phanerozoic isolated platforms. The data and comparisons among parameters reveal numerous trends, including observations that (1) syndepositional tectonics has been interpreted to play an important role in initiation, growth, or demise of more than 44% of isolated platforms; (2) tectonically active platforms are more likely to have higher aspect ratios (more elongate in plan-view and more squat in cross section); (3) stratal geometries are not distributed randomly in time (by era, p = 0.00, and by system, p = 0.04), although aggradational isolated platforms are most common within and among all eras (63% of all platforms); (4) sizes (area, long axis length), thicknesses, and aspect ratios (long axis:short axis; long axis:thickness) of isolated platforms are distinct among Phanerozoic platforms of different eras and systems; (5) although individual platforms steepen as they grow taller, syndepositional relief is not correlated (R2 = 0.04) with depositional gradient among isolated platforms across the Phanerozoic; (6) causes of isolated platform termination vary nonrandomly through the Phanerozoic (by era, p = 0.00, and by system, p = 0.00). Of all eras, Cenozoic platforms are most likely to drown (68%), in some instances through an association with clastic influx (19%). Subaerial exposure more commonly contributed to the demise of Mesozoic (45%) and Paleozoic (37%) platforms than to that of Cenozoic (13%) platforms. These results, supplemented by more granular comparison of numerous individual platforms, compliment earlier syntheses that focus on the nature of secular changes. The insights suggest that although each platform is unique in many ways, Phanerozoic isolated carbonate platforms include numerous themes that are persistent across ages, sizes, settings, and component biota.
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Basu, Anamika, Anasua Sarkar, and Piyali Basak. "Nutraceuticals for Human Health and Hypersensitivity Reaction." In Research Anthology on Recent Advancements in Ethnopharmacology and Nutraceuticals, 1184–202. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3546-5.ch056.
Повний текст джерелаАнотація:
An allergy is an overreaction of the immune system to a substance called an antigen, e.g., pollen from grasses, dust mites, etc. The drugs used for allergy in allopathy have undesirable side effects. The use of medicinal plants becomes popular due to the adverse effects of allopathic drugs. Nutraceuticals are food playing a significant role in maintaining normal physiological function. Mast cells are immunologically important cells found in almost all parts of our body, and contain histamines, leukotrienes within their granular sacs, along with those of basophils, are responsible for the symptoms of allergy. According to sources mast cell stabilizers can be classified into three categories, e.g., synthetic, semi synthetic and natural. Mast cell stabilising agents from natural resources can be obtained from different group of compounds, e.g., flavonoids, coumarins, phenols, terpenoids, alkaloids. In this book chapter, the active constituents present in them and their mode of action are highlighted using techniques of computational biology, e.g., molecular docking, etc.
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Malhotra, Hemant, Lalit Kumar, Pankaj Malhotra, Devendra Hiwase, and Ravi Bhatia. "Chronic leukaemias." In Oxford Textbook of Oncology, 754–81. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199656103.003.0052.
Повний текст джерелаАнотація:
Chronic Leukaemia, as contrasted to the acute luekemia, are slowly growing clonal malignancies of the hematopoietic system in which, even without active intervention, survival is possible for several years. In the past decade there have been several advances in the basic understanding of these diseases which have lead to improvement in survival of several decades in the majority of patients which is now being referred to as ‘operational cure’. This chapter covers the chronic leukaemias (chronic myeloid leukaemia (CML), chronic lymphocytic leukaemia (CLL), hairy cell leukaemia, prolymphocytic leukaemia, large granular lymphocytic leukaemia (LGL), and hairy cell leukaemia variant (HCL-v), including epidemiology, staging and diagnosis, molecular biology, pathology, medical management, disease monitoring, management of relapse/refraction, and future directions.
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O’Toole, Jane, and Ann Devitt. "Twitter as a dynamic language learning platform for learners of Irish as an additional language in a primary school setting in Ireland: review and recommendations." In Intelligent CALL, granular systems and learner data: short papers from EUROCALL 2022, 302–7. Research-publishing.net, 2022. http://dx.doi.org/10.14705/rpnet.2022.61.1475.
Повний текст джерелаАнотація:
This paper explores the utilisation of Twitter as a dynamic language learning platform in order to create an authentic domain of use for learners of Irish as an Additional Language (IAL) in a primary school setting in Ireland wherein 20 fourth class children and their parents participated. The Irish language context is firstly introduced, which contextualises a rationale for utilising Twitter for language learning. Teacher, child, and parent engagement with Twitter is then outlined with reference to the action research methodology employed. The repository of class tweets, periodic participant advisory group discussions and questionnaires, coupled with teacher-researcher reflection informed a qualitative data analysis. Results indicate notable student engagement with and enjoyment of tweeting in class as Gaeilge [in Irish] whereby the class Twitter account emerged as a practicable language learning platform. Its affordances enabled the student composition and publishing of short texts (tweets) and the provision of authentic Irish tweets for class reading. Parent and child engagement out of class, while relatively low, also demonstrated a promising additional domain of use, subject to the negotiation of orientation-related and implementation-related challenges for learners in a blended setting. In conclusion, recommendations to support the use of Twitter in endangered language school contexts are suggested.
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Santa, Kazuki. "Macrophages: Phagocytosis, Antigen Presentation, and Activation of Immunity." In Phagocytosis - Main Key of Immune System [Working Title]. IntechOpen, 2023. http://dx.doi.org/10.5772/intechopen.110832.
Повний текст джерелаАнотація:
Macrophages are phagocytes and one of the white blood cells discovered by Ilya I. Mechnikov in 1892. They engulf and digest foreign substances like pathogens and conduct antigen presentation, mature from haematopoietic stem cells in bone marrow, moving into blood vessels and become monocytes, and differentiate into macrophages in the tissue. Macrophages have intracellular granules called lysosome accumulating digestive enzymes. Their life span is several months and proliferates by cell division. There are three roles: First one is phagocytosis. Macrophages incorporate pathogens and work in natural immunity. In inflammation, macrophages aggregate after neutrophils recruitment and engulf pathogens into cellular phagosomes, fused with lysosomes and degrade. Second role is antigen presentation. Macrophages present fragment of digested foreign substances on cell surface MHC class II molecules and release cytokines. Dendritic cells and B cells are also APCs expressing MHC class II. CD4+ T cells recognize antigens presented on macrophages by using TCR. Only well-matched helper T cells via MHC class II-TCR interaction are activated. The third is activation of immunity. Cytokines produced by T cells activate macrophages and differentiate them into inflammatory M1 and wound-healing M2 macrophages.
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Keitner, Chimène I. "Foreign Election Interference and International Law." In Defending Democracies, 179–96. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197556979.003.0009.
Повний текст джерелаАнотація:
This chapter explores the possibilities, and limitations, of international law in regulating states’ attempts to influence each other’s elections. The principles of sovereignty, territorial integrity, political independence, self-determination, and nonintervention reflect core understandings about the attributes and entitlements of states in the international system. The chapter begins by tracing attempts to further codify the nonintervention principle in the 1960s and 1970s. It then examines the tension produced by states’ conflicting desires to preserve the greatest possible freedom of action for themselves and to constrain the behavior of others. To date, this dynamic has impeded the ability to formulate explicit treaty-based solutions to the problem of foreign election interference. Identifying customary international law in this area requires inferring specific conduct-regulating rules from general principles, which can yield contested results. States are unlikely to agree to more granular, binding international rules as long as regimes currently in power benefit from constructive ambiguity. Although agreement on more concrete rules and enforcement mechanisms might remain elusive, like-minded states should continue to emphasize the importance of supporting peoples’ abilities to determine their own political destinies. This requires, at a minimum, promoting an antideception norm as a matter of both domestic and international law.
Тези доповідей конференцій з теми "Active Granular Systems"
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Mukherjee, Rudranarayan, and Isaac Kim. "Massively Parallel Discrete Element Modeling of Legged Mobility on Granular Terrain." In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13329.
Повний текст джерелаАнотація:
Legged mobility of robotic systems is an active area of research. Quantitatively understanding mobility of these systems on natural terrain is critical for design and operations of these systems. In this paper, we present results of computational simulations of legged mobility on granular terrain using massively parallel Discrete Element Method. We model the interactions of a leg from a micro ground vehicle with sandy terrain made of polydispersed granular media. In these simulations, we model the interactions between millions of granules and the leg to quantify ground reactions and associated qualitative behaviors. The simulations are run on parallel computers to overcome the severe computational complexity of simulating these large problems in physically feasible time-frames. We are using high fidelity first-principles approaches to model emergent complex behavior that cannot otherwise be modeled. We present results from a parametric sweep where different leg speeds and penetrations are used to understand differences in ground reaction.
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Safitri, Anissa Sukma, and Roald Kommedal. "Effect of temperatures on anaerobic granulated biofilm modelling." In 63rd International Conference of Scandinavian Simulation Society, SIMS 2022, Trondheim, Norway, September 20-21, 2022. Linköping University Electronic Press, 2022. http://dx.doi.org/10.3384/ecp192030.
Повний текст джерелаАнотація:
Anaerobic granulated biomass-based treatment is a sustainable alternative for municipal wastewater treatment. Each granule in the system is comprised of a complex community of anaerobic microorganisms embedded in a biofilm matrix. The aim of this work was to implement a biofilm model for simulation of biogas production and COD removal as observed in an experimental up-flow anaerobic sludge blanket (UASB) reactor system. Additionally, selected scenario simulations were carried out to assess the effect of temperatures (25, 16, and 12 °C) on granulated anaerobic reactor performance at different organic loading rates. The two main model components used are: Dynamic biochemical and physicochemical conversion processes (Anaerobic Digestion Model No. 1) and diffusive mass transfer within the granule (biofilm). The model was implemented in AQUASIM 2.1. Simulations gave insight into non-observables, especially intragranular biomass distribution and substrate profiles, which help our understanding of granule formation and evolution. Results reflected observed effluent COD concentrations and methane production rates at variable temperatures and reactor loadings. Simulations also confirmed observed steady-state reductions in COD removal efficiencies and methane fraction in biogas at increasing organic loading rate. Model simulations also showed intra-granular alkaline pH depth profiles with increasing organic loading rate which may explain calcium-based mineral core formation. The biomass composition and active regions in granules were not significantly affected by organic loading rate. At steady state, organic substrates especially monosaccharides and volatile fatty acids were predicted to degrade approximately within the outer 100 μm. In general, the model can be used as a tool to predict and simulate anaerobic granulated biofilm system performances in UASB reactor.
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Kerr, Vicki. "Performing nature unnaturally: Musique concrète and the performance of knowledge - one seabird at a time." In LINK 2021. Tuwhera Open Access, 2021. http://dx.doi.org/10.24135/link2021.v2i1.129.
Повний текст джерелаАнотація:
Migratory seabirds are an unseen conduit between marine and terrestrial systems, carrying the nutrients they consume at sea into the forests where they breed. Acting as environmental sentinels, their health and reproductive success provide early warning signals of deteriorating marine eco-systems as the climate changes, and fish stocks decrease. Aotearoa New Zealand is the seabird capital of the world, with ~25% of all species breeding here and ~10% exclusively so. They play a critical role in maintaining healthy ecosystems, with their long-term well-being is closely interconnected with our own prospects for a sustainable future. Now predominantly restricted to off-shore islands due to predation and habitat destruction, seabirds and their familiar sounds have become less available in an age when the unprecedented global movement and planetary spread of the human population has culminated in unsustainable fishing, predators and habitat destruction. Inspiring mythology, song, poetry and stories, birds have been significant in shaping our understanding of how our natural environment has come to be known and understood. This paper speculates upon how we learn to communicate and cooperate with these precious taonga, and what might be learned from such an exchange through creative practice. Reflecting upon what birds might tell us, musician Matthew Bannister and I, a visual artist, have taken our cue from seabirds sharing our local environment on the west coast of Aotearoa - from the petrel (peera) through to the gannet (tākapu). Working on the premise that bird vocalisation is a performed negotiation that includes defence of territory and mate attraction, a bird’s call is a form of communication that effectively says “Come here” or “Go away”, which arguably is true of music – marking a social space and time to invite or repel. Rather than limiting bird calls to functionalist categories of explanation, we ask whether seabirds can communicate and exchange information about environmental changes using a malleable vocabulary, comprised of unique acoustic units arranged and re-arranged sequentially for greater communicative depth. Granting a high level of agency and creativity to birds as opposed to believing a bird only avails itself of stereotyped ‘speech’ to survive an accident-rich environment, places greater importance on responses that are improvised directly upon environmental stimuli as irritant rather than as a signal. Matthew explores bird calls via musique concrète, sampling recordings of seabirds to abstract the musical values of bird song conventions – a human response to the ‘other’ in jointly formed compositions, reflecting a living evolving relationship between composer and bird. In further developing our research into a multimedia artwork, I shall extend a technique used for electroacoustic composition (granular synthesis) to video portraits of composer/performer and bird. In applying granular synthesis techniques to video, tiny units of image and sampled sound are reassembled within the frames. Through the mixing of existing synthesised sequences, performer/composer and bird become active participants in the making and remaking of a shared environment, articulating the limits of space/territory to find new ways to be heard within it.
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Hao, Yan-Bin, Xiao Guo, and Nai-Ding Yang. "Research on information system attribute set information granules based on functional dependency." In 2014 11th International Computer Conference on Wavelet Active Media Technology and Information Processing (ICCWAMTIP). IEEE, 2014. http://dx.doi.org/10.1109/iccwamtip.2014.7073362.
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Tannoury, George A., and Steven D. Schrock. "Introduction to Chemical Stabilization of Unstable Trackbeds." In 2016 Joint Rail Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/jrc2016-5779.
Повний текст джерелаАнотація:
Trackbeds are typically composed of all granular materials comprised of ballast and subballast over compacted subgrade. Most poor performances of railroads can be attributed to poor and unstable subgrade conditions. Below the surface, the instability of the subgrade material can propagate through the granular zone leading to excessive settlements and deformations of the railway. Conventional subgrade restoration in the trackbed system requires the removal of the granular materials and over-excavation of soft unstable subgrade materials, moisture adjustment, re-compaction, and sometimes chemical stabilization of the subgrade soils. Since these procedures are considered very expensive in terms of construction equipment, railway outage time, and labor force, alternative solutions for consideration and evaluation are essential. Injection of expansive foam (polymer based) materials is a relatively recent method that has been used in various applications of soil stabilization in the roadway industry. This technique relies on the injection of rigid-polyurethane foam, which is a high-density, expanding, thermoset, hydro-insensitive and environmentally neutral polyurethane-resin product, into the soft and unstable soil to improve their shear strength and stability index. In addition, the stabilized zone acts as a waterproof membrane protecting moisture sensitive subgrade, and acting as a separation layer to eliminate pumping and contamination of the granular subballast at saturated fine grained conditions. The objective of this paper is to evaluate the practicability of polyurethane stabilized soft and unstable subgrade under unbounded granular trackbeds to mitigate future deformation, restore railway foundation, and reduce trackbed repair cost and outage time.
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Mazzola, Sergio, and Marco Minoia. "Improving sensing action via multi-agent based system with statistical and granular approach." In 2018 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS). IEEE, 2018. http://dx.doi.org/10.1109/eesms.2018.8405823.
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Darigo, Nancy, Sri Rajah, and Luke Boggess. "Preliminary Surface Fault Assessment and Conceptual Fault Crossing Design of Proposed Gas Pipeline, South-Central Alaska." In 2008 7th International Pipeline Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ipc2008-64431.
Повний текст джерелаАнотація:
A preliminary geologic and engineering study of fault crossings along a proposed high pressure natural gas spur pipeline was conducted in 2005 for the Alaska Natural Gas Development Authority (ANGDA). The route crosses a number of faults that comprise the eastern Castle Mountain-Caribou fault system in south-central Alaska, which is known to be active within 60 miles (100 km) to the west. The route approaches the faults at mostly subparallel angles, resulting in several long coincident crossings, five of which were judged to be potentially active in this study. Maximum displacements of 7 feet (2.1 m) in both vertical and horizontal directions were conservatively estimated for each crossing based on a maximum magnitude 7.0 earthquake and 700-year return period suggested for the western Castle Mountain fault. Preliminary design permanent displacements were recommended as 2/3rds of the maximum. A conceptual buried crossing design in a sloped wall trench with a double geomembrane liner and loose granular backfill would accommodate both vertical and lateral displacements. Additional geologic studies could potentially substantiate longer return periods and lead to a reduction in the number of crossings, crossing lengths, and displacement values. If design displacements are close to allowable settlement criteria, the fault crossings could be eliminated from requiring special design.
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Sims, Neil D., Ashan Amarasinghe, and Keith Ridgway. "Particle Dampers for Workpiece Chatter Mitigation." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82687.
Повний текст джерелаАнотація:
It is well known that the chatter stability of a machining process can be improved by increasing the structural damping of the system. To date this approach has been effectively used on various components of the machining system, for example boring bars, milling tools, and the machine structure itself. Various damping treatments have been proposed, including tuned vibration absorbers, active methods, and impact dampers. However, to date there has been little or no work to investigate the issue of particle dampers for this application. This special class of damper comprises a container of thousands of small granular particles which dissipate energy by friction and impact when the container vibrates. The resulting behaviour is highly nonlinear but can provide very high levels of damping across a wide frequency range. In the present study, particle dampers were applied to a workpiece to mitigate chatter during milling, and the limiting critical depth of cut was increased by an order of magnitude. This article gives an overview of the particle damper’s behaviour and key design parameters. Cutting trials employing the device are then described.
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Rose, Jerry G., Paulo Fonseca Teixeira, and Nathan E. Ridgway. "Utilization of Asphalt/Bituminous Layers and Coatings in Railway Trackbeds: A Compendium of International Applications." In 2010 Joint Rail Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/jrc2010-36146.
Повний текст джерелаАнотація:
During the past thirty years the use of a layer(s) of hot-mix asphalt pavement within railway track structures has steadily increased until it is becoming a common consideration or practice for specific conditions and areas in several countries throughout the world. This practice augments, and for certain designs replace, the traditional granular support materials. It is considered to be a premium trackbed design. The primary documented benefits are to provide additional support to improve load distributing capabilities of the trackbed components, decrease load-induced subgrade pressures, improve and control drainage, insure maintenance of specified track geometric properties for heavy tonnage freight lines and high-speed passenger lines, and decrease subsequent expenditures for trackbed maintenance and component replacement costs. The asphalt layer is normally used in combination with traditional granular layers to achieve various configurations. This paper presents a compendium of International Asphalt Trackbed Applications. The various factors are discussed that are considered in the design phases and subsequent performance-based tests and analyses. Illustrations include typical sectional views of the trackbed/roadbed components and thicknesses and photographs of construction and finished views for various asphalt trackbed applications in several countries. Following are brief accounts for selected significant international activities emphasizing high-speed and intercity passenger rail line applications. In the United States the use of asphalt trackbeds has steadily grown since the early 1980’s. It is primarily used for maintenance (cure-all) applications in existing tracks to improve trackbed performance and for new trackbed construction where the projected superior performance of asphalt trackbeds can be justified economically. Typically the asphalt layer is 15 cm thick and is topped with conventional ballast. This application does not deviate significantly from typical designs, except the asphalt is substituted for a portion of the granular support materials. Several other countries are actively involved with the construction of new segments or complete rail lines using asphalt (frequently termed – bituminous) trackbeds. For instance, Japan has used asphalt trackbeds on certain test sections for their high-speed rail lines since the 1960’s, but since the 1970’s asphalt trackbeds with ballast cover is a standard on newly constructed rail lines. The 5-cm thickness of asphalt primarily serves as a waterproofing layer and facilitates drainage. The Japanese believe that this will assist in reducing subsequent maintenance costs associated with ballast fouling from subgrade pumping. The Japanese have recently instigated a performance-rank design system. Asphalt trackbed designs are either required or are an option for the two premium trackbed performance ranks. Italy represents another country heavily involved with incorporating asphalt trackbeds in their rail lines. In the late 1970’s Italy placed test sections of both asphalt and concrete on their original Rome to Florence high-speed line. From the Italian perspective the asphalt out-performed the other test sections, leading to standards requiring the use of asphalt trackbeds on all newly constructed high-speed passenger rail lines. The typical asphalt layer thickness is 12 cm. Germany has focused on using asphalt for ballastless trackbed designs. The main asphalt track in use in Germany consists of concrete ties or slab track placed on a 26 to 30-cm thick layer of asphalt. Various designs are incorporated into the system. Recently France installed a 3-km test section of asphalt on their Paris to Strasbourg Eastbound High-Speed Line. The French are currently observing the effects of high-speed trains traversing various test sections to determine how beneficial the use of asphalt trackbeds will be for future high-speed passenger lines. The sections are heavily instrumented for analyzing numerous trackbed induced effects on ride quality and other aspects. Other countries, a recent addition includes Spain, are involved to varying degrees with the development of asphalt trackbed technology, particularly for high-speed and intercity passenger rail lines. Pertinent information and documentation of recent findings and results are included in the paper.
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Tatli, Emre, Sung Jin Lee, Jun Liao, and Paolo Ferroni. "Assessment of Passive Cooling Capability of the Westinghouse Lead Fast Reactor Under Station Blackout Conditions." In 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-91821.
Повний текст джерелаАнотація:
Abstract Westinghouse is developing its next generation of high-capacity nuclear power plants with the Westinghouse Lead-cooled Fast Reactor (LFR) (Ref. 1). The Westinghouse LFR is a pool-type 950 MWt (∼450 MWe Net) passively safe modular construction plant that contains all the primary system components within the reactor vessel, including the reactor coolant pumps (RCPs) and the primary heat exchangers (PHEs). Similar to the Westinghouse AP1000® Pressurized Water Reactor design, the Westinghouse LFR design incorporates passive cooling capability primarily through its Passive Heat Removal System (PHRS). During accidents, the PHRS allows decay heat to be transferred from the core to a pool of water surrounding the guard vessel, which transitions to long-term air cooling upon water depletion. All of this takes place without operator action or need for moving parts or power supply. Overall, when combined with natural circulation of liquid lead inside of the reactor vessel, this passive system fully relies on natural circulation, thermal radiation and boiling mechanisms to transport decay heat from the core to the atmosphere. In this study, complementary Computational Fluid Dynamics (CFD) and system code analyses were performed to assess the passive cooling ability of the Westinghouse LFR design during station blackout (SBO) conditions. The postulated scenario examined in this study is the longer-term phase of the SBO event, with the RCPs and PHEs assumed to be inactive and the water inventory in the pool exterior to the guard vessel fully depleted, thus relying purely on air cooling as the ultimate heat sink. The CFD analysis was conducted with Siemens STAR-CCM+ code using, as domain, the primary lead pool and with boundary conditions provided by the containment code GOTHIC. The CFD analyses provided high fidelity resolution of the three-dimensional natural circulation flow patterns formed throughout the reactor vessel. The results of the study not only provided confirmation of the passive cooling capability of the Westinghouse LFR design during an SBO event, but also provided granular input for vessel structural analysis activities accounting for thermal gradients developed during an SBO event.
Звіти організацій з теми "Active Granular Systems"
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Shmulevich, Itzhak, Shrini Upadhyaya, Dror Rubinstein, Zvika Asaf, and Jeffrey P. Mitchell. Developing Simulation Tool for the Prediction of Cohesive Behavior Agricultural Materials Using Discrete Element Modeling. United States Department of Agriculture, October 2011. http://dx.doi.org/10.32747/2011.7697108.bard.
Повний текст джерелаАнотація:
The underlying similarity between soils, grains, fertilizers, concentrated animal feed, pellets, and mixtures is that they are all granular materials used in agriculture. Modeling such materials is a complex process due to the spatial variability of such media, the origin of the material (natural or biological), the nonlinearity of these materials, the contact phenomenon and flow that occur at the interface zone and between these granular materials, as well as the dynamic effect of the interaction process. The lack of a tool for studying such materials has limited the understanding of the phenomena relevant to them, which in turn has led to energy loss and poor quality products. The objective of this study was to develop a reliable prediction simulation tool for cohesive agricultural particle materials using Discrete Element Modeling (DEM). The specific objectives of this study were (1) to develop and verify a 3D cohesionless agricultural soil-tillage tool interaction model that enables the prediction of displacement and flow in the soil media, as well as forces acting on various tillage tools, using the discrete element method; (2) to develop a micro model for the DEM formulation by creating a cohesive contact model based on liquid bridge forces for various agriculture materials; (3) to extend the model to include both plastic and cohesive behavior of various materials, such as grain and soil structures (e.g., compaction level), textures (e.g., clay, loam, several grains), and moisture contents; (4) to develop a method to obtain the parameters for the cohesion contact model to represent specific materials. A DEM model was developed that can represent both plastic and cohesive behavior of soil. Soil cohesive behavior was achieved by considering tensile force between elements. The developed DEM model well represented the effect of wedge shape on soil behavior and reaction force. Laboratory test results showed that wedge penetration resistance in highly compacted soil was two times greater than that in low compacted soil, whereas DEM simulation with parameters obtained from the test of low compacted soil could not simply be extended to that of high compacted soil. The modified model took into account soil failure strength that could be changed with soil compaction. A three dimensional representation composed of normal displacement, shear failure strength and tensile failure strength was proposed to design mechanical properties between elements. The model based on the liquid bridge theory. An inter particle tension force measurement tool was developed and calibrated A comprehensive study of the parameters of the contact model for the DEM taking into account the cohesive/water-bridge was performed on various agricultural grains using this measurement tool. The modified DEM model was compared and validated against the test results. With the newly developed model and procedure for determination of DEM parameters, we could reproduce the high compacted soil behavior and reaction forces both qualitatively and quantitatively for the soil conditions and wedge shapes used in this study. Moreover, the effect of wedge shape on soil behavior and reaction force was well represented with the same parameters. During the research we made use of the commercial PFC3D to analyze soil tillage implements. An investigation was made of three different head drillers. A comparison of three commonly used soil tillage systems was completed, such as moldboard plow, disc plow and chisel plow. It can be concluded that the soil condition after plowing by the specific implement can be predicted by the DEM model. The chisel plow is the most economic tool for increasing soil porosity. The moldboard is the best tool for soil manipulation. It can be concluded that the discrete element simulation can be used as a reliable engineering tool for soil-implement interaction quantitatively and qualitatively.