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Статті в журналах з теми "Current flow reactor"
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Rehman, Asim, Muhammad Nawaz, Arshad Chughtai, Muhammad Arif Butt, and Abdul Sattar. "Catalytic Hydrodechlorination of 2,4-Dichlorophenol Using Co-Current Down Flow Contactor Reactor." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 58, no. 1 (April 25, 2015): 1–7. http://dx.doi.org/10.52763/pjsir.phys.sci.58.1.2015.1.7.
Повний текст джерелаАнотація:
In this study, a new prospective regarding application of gas liquid reactions in the presence of catalyst was studied for pollution abatement in the novel reactor. Catalytic hydrodechlorination (CHDC)of 2,4-dichlorophenol (2,4-DCP) in aqueous system was carried out under the operating conditions at 25- 75 °C, 1 atm in co-current down flow contactor reactor. Under these reaction conditions complete conversion of 2,4-DCP into less toxic products (phenol and cyclohexanone) was achieved using 5% Pd/C catalyst. At typical temperature the hydrodechlorination reaction of 2,4-DCP was completed after 10 min. 2,4-DCP was converted to 96.19% of phenol and 3.81% of cyclohexanone using 0.4 g/L of 5% Pd/C catalyst. The increase in initial concentration of 2,4-DCP resulted in the increase in time for the dechlorination of 2,4- DCP. The calculated activation energy values amounted to 43 KJ/mol for the CHDC of 2,4-DCP exhibiting that this reaction occurs mainly under the surface reaction rate controlled condition.
2
Luo, Minghan, Wenjie Xu, and Taeseop Jeong. "Development and numerical modelling of a novel UV/H2O2 rotating flow reactor for water treatment." Water Science and Technology 83, no. 5 (February 12, 2021): 1217–29. http://dx.doi.org/10.2166/wst.2021.063.
Повний текст джерелаАнотація:
Abstract The ultraviolet photochemical degradation process is widely applied in wastewater treatment due to its low cost, high efficiency and sustainability. In this study, a novel rotating flow reactor was developed for UV-initiated photochemical reactions. The reactor was run in a continuous flow mode, and the tangential installation of the inlet and outlet on the annular reactor improved reaction rates. Numerical modelling, which combined solute transport, radiation transfer and photochemical kinetic degradation processes, was conducted to evaluate improvement compared to current reactor designs. Methylene Blue (MB) decomposition efficiency from the modelling results and the experimental data agreed well with each other. The model results showed that a rotational motion of fluid was well developed inside the designed reactor for a wide range of inflow rates; the generation of ·OH radicals significantly depended on UV irradiation dose, and thus the degradation ratio of MB showed a strong correlation with the UV irradiation distribution. In addition, the comprehensive numerical modelling showed promising potential for the simulation of UV/H2O2 processes in rotating flow reactors.
3
Nazanskiy, S. L., and A. V. Solokhin. "Influence of reactor temperature conditions on the recycle flow rate." Fine Chemical Technologies 14, no. 5 (November 14, 2019): 31–38. http://dx.doi.org/10.32362/2410-6593-2019-14-5-31-38.
Повний текст джерелаАнотація:
Objectives. The problem of optimizing chemical flow sheets according to energy costs associated with recycling flows is at present quite relevant. The current article investigates the influence of temperature conditions on the recycle flow rate, securing the specified conversion of the recycled flow sheet “reactor – separation unit.”Methods. The study’s main method is the mathematical simulation of a recycled flow sheet based on material balance and chemical kinetics equations. This model assumes that the separation unit can form the recycle and outlet flows of any specified compositions.Results. The mathematical model recycle flows provides the full reagent conversion of recycled flow sheet depends on the reactor type and the temperature conditions in it. It was established that the dependence of the recycle flow rate on the reactor temperature for endothermic reactions has monotonously decreasing shape. The most interesting are exothermic reactions for which the dependence of the recycle flow rate on the reactor temperature curve has a minimum. It is proved that the “reactor – separation unit” system with the plug flow reactor has lower optimal recycle flow rate than the recycled system with the continuous stirred tank reactor. For the adiabatic reactor the dependence of total conversion recycle flow rate on the inlet reactor temperature was investigated. It has been proven that the optimal recycle flow rate is equal to the minimum recycle flow rate for total conversion in the “reactor – separation unit” system.Conclusions. It has been established that isothermal operation conditions are the best in terms of the recycle flow rate, securing the specified conversion for the system.
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Fox, David, Noel W. Dunn, Peter P. Gray, and Warwick L. Marsden. "Saccharification of bagasse using a counter-current plug-flow reactor." Journal of Chemical Technology and Biotechnology. Biotechnology 33, no. 2 (April 16, 2008): 114–18. http://dx.doi.org/10.1002/jctb.280330206.
Повний текст джерела
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Cisneros, Juan F., Manuel Raul Pelaez-Samaniego, Verónica Pinos, Ingmar Nopens, and Andrés Alvarado. "Development of an Automated Tracer Testing System for UASB Laboratory-Scale Reactors." Water 13, no. 13 (June 30, 2021): 1821. http://dx.doi.org/10.3390/w13131821.
Повний текст джерелаАнотація:
Residence time distribution (RTD) curves play an essential role in the hydraulic characterization of reactors. Current approaches for obtaining RTD curves in laboratory-scale reactors are time-consuming and subject to large errors. Thus, automated systems to obtain RTD curves in laboratory-scale reactors are of great interest for reducing experimental errors due to human interaction, minimizing experimentation costs, and continuously obtaining experimental data. An automated system for obtaining RTD curves in laboratory-scale reactors was designed, built, and tested in this work. During the tests conducted in a cylindrical upflow anaerobic sludge blanket (UASB) reactor, the system worked properly using the stimulus–response pulse technique with sodium chloride as a tracer. Four main factors were found to affect the representativeness of the RTD curves: flow stabilization time, test water conductivity, temperature, and surface tension. A discussion on these factors and the corresponding solutions is presented. The RTD curves of the UASB reactor are left-skewed with a typical tank reactor’s flow shape with channeling and dead zones. A transitory flow behavior was evidenced in the reactor, which indicates the influence of internal turbulent flow structures. The system proposed herein is expected to help study the hydraulics of reactors using laboratory-scale models more efficiently.
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Kim, Young Ho, Hyo Sub Kim, Sang Jin Han, Chu Sik Park, Ki Kwang Bae, and Jong Gyu Lee. "Bunsen Reaction Using a Counter-Current Flow Reactor in Sulfur-Iodine Hydrogen Production Process: Effects of Reactor Shape and Temperature." Advanced Materials Research 347-353 (October 2011): 3238–41. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3238.
Повний текст джерелаАнотація:
The sulfur-iodine (SI) cycle, thermochemical water splitting using heat energy from nuclear, is one of the most promising methods for massive hydrogen production. For continuous operation of Bunsen reaction section in SI process, the reactants (SO2, I2 and H2O) were fed to the reactor and the products (a H2SO4 phase and a HIx phase) were sent to storage tanks continuously during the reaction. In this study, we investigated the phase separation characteristics of continuous Bunsen reaction on the reactor shape and temperature. It was found that the reactor shape has little affected on the composition of Bunsen products. It was also observed that the phase separation characteristics of the continuous Bunsen reaction were similar to those for the semi-batch Bunsen reaction.
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Thomson, Christopher G., Ai-Lan Lee, and Filipe Vilela. "Heterogeneous photocatalysis in flow chemical reactors." Beilstein Journal of Organic Chemistry 16 (June 26, 2020): 1495–549. http://dx.doi.org/10.3762/bjoc.16.125.
Повний текст джерелаАнотація:
The synergy between photocatalysis and continuous flow chemical reactors has shifted the paradigms of photochemistry, opening new avenues of research with safer and scalable processes that can be readily implemented in academia and industry. Current state-of-the-art photocatalysts are homogeneous transition metal complexes that have favourable photophysical properties, wide electrochemical redox potentials, and photostability. However, these photocatalysts present serious drawbacks, such as toxicity, limited availability, and the overall cost of rare transition metal elements. This reduces their long-term viability, especially at an industrial scale. Heterogeneous photocatalysts (HPCats) are an attractive alternative, as the requirement for the separation and purification is largely removed, but typically at the cost of efficiency. Flow chemical reactors can, to a large extent, mitigate the loss in efficiency through reactor designs that enhance mass transport and irradiation. Herein, we review some important developments of heterogeneous photocatalytic materials and their application in flow reactors for sustainable organic synthesis. Further, the application of continuous flow heterogeneous photocatalysis in environmental remediation is briefly discussed to present some interesting reactor designs that could be implemented to enhance organic synthesis.
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Mukimin, Aris. "The Energy Production and Efficiency Treatment of ML-MFC Using High Organic Content Wastewater." E3S Web of Conferences 202 (2020): 10005. http://dx.doi.org/10.1051/e3sconf/202020210005.
Повний текст джерелаАнотація:
Microbial fuel cell (MFC) is a technology that is not only able to produce energy but also treats wastewater. The membraneless microbial fuel cell (ML-MFC) system was developed to avoid the use of membranes that are prone to clogging and are less applicable. The reactor was made and arranged in two chambers connected by pipes and the fluid flow rate is set using a peristaltic pump. Three anodes (carbon cloth) were paired with a carbon-Pt cathode GDL (Gas Diffusion Layer) type. The reactor was applied to wastewater taken from the industrial WWTP unit at the point before and after UASB. ML-MFC reactors can produce currents of 0.2 mA (before UASB) and 0.25 mA (after UASB). Current production is strongly influenced by the flow rate and characteristics of wastewater. Increased flow rates and complex character of wastewater will reduce current production. The electric power produced is 0.035 mwatt for wastewater before UASB and 0.086 mwatt after UASB with a COD removal is close to the same, which is 21% at a flow rate of 11 L / min1
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Mukimin, Aris. "The Energy Production and Efficiency Treatment of ML-MFC Using High Organic Content Wastewater." E3S Web of Conferences 202 (2020): 10006. http://dx.doi.org/10.1051/e3sconf/202020210006.
Повний текст джерелаАнотація:
Microbial fuel cell (MFC) is a technology that is not only able to produce energy but also treats wastewater. The membraneless microbial fuel cell (ML-MFC) system was developed to avoid the use of membranes that are prone to clogging and are less applicable. The reactor was made and arranged in two chambers connected by pipes and the fluid flow rate is set using a peristaltic pump. Three anodes (carbon cloth) were paired with a carbon-Pt cathode GDL (Gas Diffusion Layer) type. The reactor was applied to wastewater taken from the industrial WWTP unit at the point before and after UASB. ML-MFC reactors can produce currents of 0.2 mA (before UASB) and 0.25 mA (after UASB). Current production is strongly influenced by the flow rate and characteristics of wastewater. Increased flow rates and complex character of wastewater will reduce current production. The electric power produced is 0.035 mwatt for wastewater before UASB and 0.086 mwatt after UASB with a COD removal is close to the same, which is 21% at a flow rate of 11 L / min1
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Tighe, Christopher J., Robert I. Gruar, Cai Y. Ma, Tariq Mahmud, Xue Z. Wang, and Jawwad A. Darr. "Investigation of counter-current mixing in a continuous hydrothermal flow reactor." Journal of Supercritical Fluids 62 (February 2012): 165–72. http://dx.doi.org/10.1016/j.supflu.2011.11.027.
Повний текст джерелаДисертації з теми "Current flow reactor"
1
Yang, Li. "CFD MODELING OF MULTIPHASE COUNTER-CURRENT FLOW IN PACKED BED REACTOR FOR CARBON CAPTURE." UKnowledge, 2015. http://uknowledge.uky.edu/me_etds/59.
Повний текст джерелаАнотація:
Packed bed reactors with counter-current, gas-liquid flows have been considered to be applicable in CO2 capture systems for post-combustion processing from fossil-fueled power production units. However, the hydrodynamics within the packing used in these reactors under counter-current flow has not been assessed to provide insight into design and operational parameters that may impact reactor and reaction efficiencies. Hence, experimental testing of a laboratory-scale spherical ball, packed bed with two-phase flow was accomplished and then a meso-scale 3D CFD model was developed to numerically simulate the conditions and outcomes of the experimental tests. Also, the hydrodynamics of two-phase flow in a packed bed with structured packing were simulated using a meso-scale, 3D CFD model and then validated using empirical models.
The CFD model successfully characterized the hydrodynamics inside the packing, with a focus on parameters such as the wetted surface areas, gas-liquid interactions, liquid distributions, pressure drops, liquid holdups, film thicknesses and flow regimes. The simulation results clearly demonstrated the development of and changes in liquid distributions, wetted areas and film thicknesses under various gas and liquid flow rates. Gas and liquid interactions were observed to occur at the interface of the gas and liquid through liquid entrainment and droplet formation, and it became more dominant as the Reynolds numbers increased. Liquid film thicknesses in the structured packing were much thinner than in the spherical ball packing, and increased with increasing liquid flow rates. Gas flow rates had no significant effect on film thicknesses. Film flow and trickle flow regimes were found in both the spherical ball and structured packing. A macro-scale, porous model was also developed which was less computationally intensive than the meso-scale, 3D CFD model.
The macro-scale model was used to study the spherical ball packing and to modify its closure equations. It was found that the Ergun equation, typically used in the porous model, was not suitable for multi-phase flow. Hence, it was modified by replacing porosity with the actual pore volume within the liquid phase; this modification successfully accounted for liquid holdup which was predicted via a proposed equation.
2
Seidel, T., and M. Beyer. "Two-phase flow experiments in a model of the hot leg of a pressurised water reactor." Helmholtz-Zentrum Dresden-Rossendorf, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-85349.
Повний текст джерелаАнотація:
In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, a model of the hot leg of a pressurised water reactor was built at FZD. The hot leg model is operated in the pressure chamber of the TOPFLOW test facility, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the chamber. This technique makes it possible to visualise the two-phase flow through large windows, also at reactor-typical pressure levels. In order to optimise the optical observation possibilities, the test section was designed with a rectangular cross-section.
Experiments were performed with air and water at 1.5 and 3.0 bar at room temperature as well as with steam and water at 15, 30 and 50 bar and the corresponding saturation temperature (i.e. up to 264°C). The total of 194 runs are divided into 4 types of experiments covering stationary co-current flow, counter-current flow, flow without water circulation and transient counter-current flow limitation (CCFL) experiments.
This report provides a detailed documentation of the experiments including information on the experimental setup, experimental procedure, test matrix and on the calibration of the measuring devices. The available data is described and data sheets were arranged for each experiment in order to give an overview of the most important parameters. For the cocurrent flow experiments, water level histograms were arranged and used to characterise the flow in the hot leg. In fact, the form of the probability distribution was found to be sensitive to the boundary conditions and, therefore, is useful for the CFD comparison.
Furthermore, the flooding characteristics of the hot leg model plotted in terms of the classical Wallis parameter or Kutateladze number were found to fail to properly correlate the data of the air/water and steam/water series. Therefore, a modified Wallis parameter is proposed, which takes the effect of viscosity into account.
3
Seidel, Tobias, Christoph Vallée, Dirk Lucas, Matthias Beyer, and Darlianto Deen. "Two-phase flow experiments in a model of the hot leg of a pressurised water reactor." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-33535.
Повний текст джерелаАнотація:
In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, a model of the hot leg of a pressurised water reactor was built at FZD. The hot leg model is operated in the pressure chamber of the TOPFLOW test facility, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the chamber. This technique makes it possible to visualise the two-phase flow through large windows, also at reactor-typical pressure levels. In order to optimise the optical observation possibilities, the test section was designed with a rectangular cross-section.
Experiments were performed with air and water at 1.5 and 3.0 bar at room temperature as well as with steam and water at 15, 30 and 50 bar and the corresponding saturation temperature (i.e. up to 264°C). The total of 194 runs are divided into 4 types of experiments covering stationary co-current flow, counter-current flow, flow without water circulation and transient counter-current flow limitation (CCFL) experiments.
This report provides a detailed documentation of the experiments including information on the experimental setup, experimental procedure, test matrix and on the calibration of the measuring devices. The available data is described and data sheets were arranged for each experiment in order to give an overview of the most important parameters. For the cocurrent flow experiments, water level histograms were arranged and used to characterise the flow in the hot leg. In fact, the form of the probability distribution was found to be sensitive to the boundary conditions and, therefore, is useful for the CFD comparison.
Furthermore, the flooding characteristics of the hot leg model plotted in terms of the classical Wallis parameter or Kutateladze number were found to fail to properly correlate the data of the air/water and steam/water series. Therefore, a modified Wallis parameter is proposed, which takes the effect of viscosity into account.
4
Beyer, Matthias, Dirk Lucas, Heiko Pietruske, and Lutz Szalinski. "Two-Phase Flow Experiments on Counter-Current Flow Limitation in a model of the Hot Leg of a Pressurized Water Reactor (2015 test series)." Helmholtz-Zentrum Dresden-Rossendorf, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-216094.
Повний текст джерелаАнотація:
Counter-Current Flow Limitation (CCFL) is of importance for PWR safety analyses in several accident scenarios connected with loss of coolant. Basing on the experiences obtained during a first series of hot leg tests now new experiments on counter-current flow limitation were conducted in the TOPFLOW pressure vessel. The test series comprises air-water tests at 1 and 2 bar as well as steam-water tests at 10, 25 and 50 bar. During the experiments the flow structure was observed along the hot leg model using a high-speed camera and web-cams. In addition pressure was measured at several positions along the horizontal part and the water levels in the reactor-simulator and steam-generator-simulator tanks were determined.
This report documents the experimental setup including the description of operational and special measuring techniques, the experimental procedure and the data obtained.
From these data flooding curves were obtained basing on the Wallis parameter. The results show a slight shift of the curves in dependency of the pressure. In addition a slight decrease of the slope was found with increasing pressure. Additional investigations concern the effects of hysteresis and the frequencies of liquid slugs. The latter ones show a dependency on pressure and the mass flow rate of the injected water.
The data are available for CFD-model development and validation.
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Seidel, T., and M. Beyer. "Two-phase flow experiments in a model of the hot leg of a pressurised water reactor." Helmholtz-Zentrum Dresden-Rossendorf, 2011. https://hzdr.qucosa.de/id/qucosa%3A22146.
Повний текст джерелаАнотація:
In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, a model of the hot leg of a pressurised water reactor was built at FZD. The hot leg model is operated in the pressure chamber of the TOPFLOW test facility, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the chamber. This technique makes it possible to visualise the two-phase flow through large windows, also at reactor-typical pressure levels. In order to optimise the optical observation possibilities, the test section was designed with a rectangular cross-section.
Experiments were performed with air and water at 1.5 and 3.0 bar at room temperature as well as with steam and water at 15, 30 and 50 bar and the corresponding saturation temperature (i.e. up to 264°C). The total of 194 runs are divided into 4 types of experiments covering stationary co-current flow, counter-current flow, flow without water circulation and transient counter-current flow limitation (CCFL) experiments.
This report provides a detailed documentation of the experiments including information on the experimental setup, experimental procedure, test matrix and on the calibration of the measuring devices. The available data is described and data sheets were arranged for each experiment in order to give an overview of the most important parameters. For the cocurrent flow experiments, water level histograms were arranged and used to characterise the flow in the hot leg. In fact, the form of the probability distribution was found to be sensitive to the boundary conditions and, therefore, is useful for the CFD comparison.
Furthermore, the flooding characteristics of the hot leg model plotted in terms of the classical Wallis parameter or Kutateladze number were found to fail to properly correlate the data of the air/water and steam/water series. Therefore, a modified Wallis parameter is proposed, which takes the effect of viscosity into account.
6
Брусак, Василь Юрійович. "Автоматизація установки каталітичного крекінгу з прямоточним реактором". Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2019. https://ela.kpi.ua/handle/123456789/29050.
Повний текст джерелаАнотація:
Дипломний проект бакалавра на тему: «Автоматизація установки каталітичного крекінгу з прямоточним реактором» містить пояснювальну записку об ̓ємом 61 сторінок, специфікацію для функціональної схеми об ̓ємом 4 сторінок.
Пояснювальна записка містить 5 розділів, 1 додаток та 11 літературних джерел.
В дипломному проекті бакалавра виконаний аналіз технологічної схеми каатлітичного крекінгу з прямоточним реактором, як об ̓єкта автоматизації. Розроблено функціональну схему автоматизації для цього ж процесу, принципову електричну схему аварійного захисту і технологічного блокування електродвигунів, принципово електричну схему технологічної сигналізації контрольованих параметрів.
В роботі розглянуто особливості роботи ректифікаційної колони, як об ̓єкта керування. Для цього ж апарату розроблено математичну модель статичного та динамічного режиму роботи. За допомогою цієї моделі виконані розрахунки статичних характеристик по каналу збурення і керування. Виконано синтез системи керування. В цьому ж розділі зроблені висновки та рекомендації по використанню тих чи інших регуляторів.
При виконанні дипломного проекту були використані методи теорії автоматичного керування, математичного моделювання.
Основні результати роботи можуть бути використані для попередньої оцінки параметрів налаштування реальних систем керування.Bachelor's degree project on the theme: «Automation of catalytic cracking installation with a direct current reactor» includes an explanatory note Capacity 61 pages, the specification for functional circuits Capacity 4 pages. Explanatory note contains 5 chapters, appendix and 11 references. Bachelor's degree project in the analysis of catalytic cracking installation with a direct current reactor, as the object of automation. The functional diagram for automating this process and is essentially an electrical circuit, remote control, emergency protection and technology block, fundamentally electric circuit of technological signaling. In operation rectification column, as objects of control. For the same apparatus the mathematical models of static and dynamic modes. With these models, calculations of static characteristics of disturbance and control channels. Done synthesis control system. In the same section, conclusions and recommendations on the use of certain regulators. In the performance diploma methods were used control theory, mathematical modeling. The results of theses published in international conferences. The main findings can be used to estimate the parameters of real systems configuration management.
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Litrico, Giuliana. "Strongly coupled models for the prediction of electrochemical reactors performances." Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/11859.
Повний текст джерелаАнотація:
La modélisation mathématique des systèmes électrochimiques, et en général la modélisa-
tion des systèmes fluidiques réactifs en présence de champs électriques, est un problème
d’une complexité telle que des solutions analytiques n’existent que dans des cas très simpli-
fiés et la solution numérique est, malgré toute la puissance de calcul moderne, encore très
difficile. À ce jour, les avancées dans la modélisation au niveau des modèles d’écoulement
sont majeures, mais la modélisation couplée de l’écoulement, avec le champ électrique en
présence de solutions concentrées demeure encore un défi de taille. Le couplage des diffé-
rents champs décrits par les modèles mathématiques devient critique dans les régions où
ont lieu les réactions hétérogènes aux interfaces chargées modélisées par l’équation non
linéaire de Butler-Volmer.
Les logiciels commerciaux modernes commencent à permettre de coupler les modules
d’électrochimie avec la mécanique des fluides numérique (CFD), mais l’ impossibilité d’ac-
céder au code source ne permet pas au chercheur de modifier à volonté la formulation
des modèles. Par conséquent, le projet de recherche actuel vise le développement d’une
plate-forme logicielle ouverte (open-source) comme OpenFOAM, qui peut garantir une
complète accessibilité au code-source, la liberté des utilisateurs à faire des modifications,
la transparence des détails des modèles, et tous les autres développements qui sont requis
pour chaque problème rencontré par les chercheurs.
Le développement de modèles reposant sur des lois physiques établies permettra la modéli-
sation des systèmes électrochimiques complexes, et la compréhension des phénomènes qui
s’y déroulent. Il vise la modélisation du transfert de masse d’une cellule où l’écoulement
de la solution concentrée (molten salt) est turbulent, biphasique et incompressible, et les
réactions électrochimiques de surface sont calculées en utilisant une distribution tertiaire
de densité de courant. Le principal enjeu sur le plan scientifique, dans le cadre de ce projet,
demeure donc de développer un modèle qui soit bien calé sur le problème technologique
visé afin qu’il puisse reproduire de façon réaliste les systèmes électrochimiques. Il vise éga-
lement à amener la modélisation à un point où l’outil pourra être utilisé comme instrument
de prédiction et de validation de nouveaux concepts des systèmes électrochimiques.Abstract: The modeling of electrochemical systems, and in general the modeling of reacting flows ex- posed to electric field, is a complex problem to the point that analytic solutions exist only for simplified cases despite the increasing computer power. The state of art shows major improvements in the fluid-dynamics of electrochemical reactors; but the full coupling of the flow with the electric field in presence of concentrated electrolytic solutions still needs to be properly investigated. The coupling gets even more critical along the charged in- terfaces where heterogeneous reactions are modeled through the non-linear Butler-Volmer equation. Commercial software are slowly try to connect electrochemical modules to the well val- idated CFDs, but most of the time costly licenses, and poor accessibility to the source code, do not allow a deep integration between the two. Instead, this research study pro- poses an open-source code implemented in OpenFOAM, that guarantees full accessibility to the source code, user’s modifications, full transparency of the model’s details, and any possible further developments required by the specificity of the problem. The final code implements the mass transfer of a cell where the concentrated solution (molten salt) is a two-phase turbulent incompressible flow and the electrochemical surface reactions consider tertiary current distributions. The aim of this work is to create an open source platform to predict and analyze industrial reactor’s performances. The advanced modeling can be later exploited and used as a validation instrument for new electrochemical concepts.
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Kumar, Mithlesh. "Magnetic flux distorsion in two-phase liquid metal flow." Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/15854/1/Kumar_1.pdf.
Повний текст джерелаАнотація:
A Generation IV Sodium cooled Fast Reactor (SFR) is being researched and developed at CEA, Cadarache France under the project named ASTRID. Monitoring gas presence in SFR is important with respect to its safe operation. In accordance with the principles of diversity, techniques based on different measurement principles have been proposed. This thesis concerns the detection and characterization of void using magnetic flux perturbation principle. An Eddy Current Flow Meter (ECFM) device is used for this purpose. From the technological point of view, the objective is to evaluate the feasibility of ECFM as a flow and/or void monitoring/characterizing device; and to determine which parameters are of interest and what are the precision of these measurements; and whether it is possible to measure the flow rate and void fraction simultaneously with the same ECFM device. From the physics point of view, the ECFM system involves the magnetic flux perturbation due to voids in the presence of Faraday induction and Lorentz force effects. Therefore ECFM integrated signal contains informations about the void, Faraday induction and Lorentz force effects based perturbation in magnetic flux and their couplings. Our objective is to understand the nature and extent of these couplings. Specific experiments have been developed to study the effects of flow velocity, void fraction and magnetic flux pulsations on the response of an ECFM. It consists in modeling the two-phase flow by a moving aluminium rod (plug flow) with holes and grooves to simulate voids. Flow velocity range of variation was 0
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Romero, Hamers Adolfo. "STUDY OF THE THERMAL STRATIFICATION IN PWR REACTORS AND THE PTS (PRESSURIZED THERMAL SHOCK) PHENOMENON." Doctoral thesis, Editorial Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/36536.
Повний текст джерелаАнотація:
In the event of hypothetical accident scenarios in PWR, emergency strategies have to be mapped out, in order to guarantee the reliable removal of decay heat from the reactor core, also in case of component breakdown. One essential passive heat removal mechanism is the reflux condensation cooling mode. This mode can appear for instance during a small break loss-of-coolant-accident (LOCA) or because of loss of residual heat removal (RHR) system during mid loop operation at plant outage after the reactor shutdown.
In the scenario of a loss-of-coolant-accident (LOCA), which is caused by the leakage at any location in the primary circuit, it is considered that the reactor will be depressurized and vaporization will take place, thereby creating steam in the PWR primary side. Should this lead to ¿reflux condensation¿, which may be a favorable event progression, the generated steam will flow to the steam generator through the hot leg.
This steam will condense in the steam generator and the condensate will flow back through the hot leg to the reactor, resulting in counter-current steam/water flow. In some scenarios, the success of core cooling depends on the behaviour of this counter-current flow.
Over several decades, a number of experimental and theoretical studies of counter-current gas¿liquid two-phase flow have been carried out to understand the fundamental aspect of the flooding mechanism and to prove practical knowledge for the safety design of nuclear reactors. Starting from the pioneering paper of Wallis (1961), extensive CCFL data have been accumulated from experimental studies dealing with a diverse array of conditions
A one-dimensional two field model was developed in order to predict the counter-current steam and liquid flow that results under certain conditions in the cold leg of a PWR when a SBLOCA (small break loss of coolant accident) in the hot leg is produced.
The counter-current model that has been developed can predict the pressure, temperature, velocity profiles for both phases, also by taking into account the HPI injection system in the cold leg under a counter-current flow scenario in the cold leg. This computer code predicts this scenario by solving the mass, momentum and energy conservation equations for the liquid and for the steam separately, and linking them by using the interfacial and at the steam wall condensation and heat transfer, and the interfacial friction as the closure relations.
The convective terms which appear in the discretization of the mass and energy conservation equations, were evaluated using the ULTIMATE-SOU (second order upwinding) method. For the momentum equation convective terms the ULTIMATE-QUICKEST method was used.
The steam-water counter-current developed code has been validated using some experimental data extracted from some previously published articles about the direct condensation phenomenon for stratified two-phase flow and experimental data from the LAOKOON experimental facility at the Technical University of Munich.Romero Hamers, A. (2014). STUDY OF THE THERMAL STRATIFICATION IN PWR REACTORS AND THE PTS (PRESSURIZED THERMAL SHOCK) PHENOMENON [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36536
Alfresco
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Colpo, Sarah E. "Pressurizer surge line Counter Current Flow Limitation during AP600 Mode 5 Cold Shutdown." Thesis, 1999. http://hdl.handle.net/1957/33578.
Повний текст джерелаАнотація:
Counter Current Flow Limitation (CCFL) was observed in the pressurizer surge line of
the Oregon State University APEX facility during test NRC-10. This test simulated a one-inch
diameter cold leg break with a failure of three of four of the fourth-stage Automatic
Depressurization System (ADS) valves. The result was a high vapor flow rate through
ADS 1-3, that caused CCFL in the pressurizer surge line and liquid holdup in the
pressurizer. Because this liquid was not available for core cooling, further study of the
passive safety systems in the AP600 under Mode 5 Cold Shutdown conditions was
deemed necessary. An analysis of the AP600 geometry and the existing CCFL database
determined that Kutateladze scaling is appropriate for the APEX and AP600 surge lines.
The Kutateladze CCFL correlation was used to assess CCFL in the APEX and AP600
pressurizer surge lines under Mode 5 Cold Shutdown conditions. The results indicate that
CCFL would be expected in the pressurizer surge lines at low pressures and decay powers
prior to ADS 4 actuation. Test NRC-35 examined CCFL and provided data to benchmark
NRC's thermal hydraulic analysis codes. This thesis presents the results of test NRC-35
and the supporting CCFL calculations.Graduation date: 1999
Книги з теми "Current flow reactor"
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Brooks, Douglas. PCB Currents: How They Flow, How They React. Pearson Education, Limited, 2013.
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PCB Currents: How They Flow, How They React. Pearson Higher Education & Professional Group, 2017.
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3
Colpo, Sarah E. Pressurizer surge line Counter Current Flow Limitation during AP600 Mode 5 Cold Shutdown. 1999.
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4
Hasegawa, T., K. Terabe, T. Sakamoto, and M. Aono. Nanoionics and its device applications. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533060.013.8.
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This article discusses nanoionics phenomena and their applications for making new types of electronic devices. It begins with an overview of ionic conductive materials, which are classified into two categories in terms of the charged particles: solid electrolytes in which only ions contribute to the current flow, and mixed electronic and ionic conductors in which bothelectrons and ions contribute to the current flow. It then describes the solid electrochemical reaction that controls metal-filament growth and shrinkage in an atomic switch, along with the fundamentals of an atomic switch. It also considers new types of atomic switches and several applications of atomic switches. Finally, it highlights some novel characteristics of the atomic switch such as small size, low power consumption, non-volatility, and low on-resistance. These characteristics enable us to improve the performance of present-day electronic devices.
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Taberlet, Pierre, Aurélie Bonin, Lucie Zinger, and Eric Coissac. DNA sequencing. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198767220.003.0007.
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The emergence of eDNA analysis is tightly linked to the development of next-generation sequencing. Chapter 7 “DNA sequencing” gives an overview of the characteristics and limitations of the main next-generation sequencing platforms. It focuses particularly on the Illumina platform, which is the only technology currently suitable for large-scale analysis with hundreds to thousands of samples. More specifically, Chapter 7 describes the Illumina library preparation process, the generation of sequencing clusters by bridge PCR on the flow cell, and the sequencing reaction itself, based on sequencing by synthesis. Finally, detailed information is provided on the meaning and coding of quality scores of the sequencing reads.
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Serhan, Randa B. Muslim Immigration to America. Edited by Jane I. Smith and Yvonne Yazbeck Haddad. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199862634.013.021.
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Muslim immigration to America has a protracted history dating back to the first coerced West and North Africans brought on ships as part of the slave trade. Yet, the notion of Muslims as a distinguishable or coherent group arose only in the aftermath of 9/11. The Muslims of the post-9/11 era are defined as fairly recent immigrants from Southeast Asia and the Arab world. Scholarship since 9/11 has implicitly accepted this categorization, whether to make the case that Muslims have been racialized or, conversely, to assess the level of terror threat they may pose. The present chapter views this issue through a longer-range lens and a looser definition of Muslim to allow for the inclusion of the earliest migration flows (coerced and voluntary) and those who are often viewed as contested Muslims, such as the Nation of Islam. In total, six migration flows are analyzed according to Alejandro Portes and Ruben Rumbaut’s conceptualization of immigrant modes of incorporation: namely governmental reception, public reaction toward newcomers, and the preexisting community. By casting this wider net and moving away from the confines of the post-9/11 backlash, this chapter evaluates the place of Islam in the lives of those who identify or are identified as Muslims. Analyzing six major migration flows that include Muslims, it finds that Islam has been secondary to the politics of populations identified as such, whether international or domestic. The Nation of Islam was treated as suspect more because of its black nationalist undertones than its claims to Islam.Palestinians, regardless of religion, were treated as terrorists because of the Arab-Israeli war, and Southeast Asian were viewed as model minorities until 9/11 despite their strong identification with Islam. In other words, the contextual elements, especially governmental reception, have a greater influence on minorities and immigrants than religion. Currently, this has meant that American Muslims have been asked to prove their allegiance to the United States. On a positive note, there are enough educated and civically engaged American Muslims that they are able to contest the imposition of a coherent Muslim identity as alien and dangerous.
Частини книг з теми "Current flow reactor"
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López, Elida M., Vicente Garza, and Joaquín Acevedo. "Modelling and simulation of coal and petcoke gasification in a Co-current flow reactor." In 16th European Symposium on Computer Aided Process Engineering and 9th International Symposium on Process Systems Engineering, 577–82. Elsevier, 2006. http://dx.doi.org/10.1016/s1570-7946(06)80107-0.
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De Luca, Domenico, Simone Di Pasquale, Marco Cherubini, Alessandro Petruzzi, and Gianni Bruna. "International Benchmark Activity in the Field of Sodium Fast Reactors." In Recent Advances on Numerical Simulations [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97812.
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Global interest in fast reactors has been growing since their inception in 1960 because they can provide efficient, safe, and sustainable energy. Their closed fuel cycle can support long-term nuclear power development as part of the world’s future energy mix and decrease the burden of nuclear waste. In addition to current fast reactors construction projects, several countries are engaged in intense R&D and innovation programs for the development of innovative, or Generation IV, fast reactor concepts. Within this framework, NINE is very actively participating in various Coordinated Research Projects (CRPs) organized by the IAEA, aimed at improving Member States’ fast reactor analytical simulation capabilities and international qualification through code-to-code comparison, as well as experimental validation on mock-up experiment results of codes currently employed in the field of fast reactors. The first CRP was focused on the benchmark analysis of Experimental Breeder Reactor II (EBR-II) Shutdown Heat Removal Test (SHRT-17), protected loss-of-flow transient, which ended in the 2017 with the publication of the IAEA-TECDOC-1819. In the framework of this project, the NINE Validation Process– developed in the framework of NEMM (NINE Evaluation Model Methodology) – has been proposed and adopted by most of the organizations to support the interpretation of the results calculated by the CRP participants and the understanding of the reasons for differences between the participants’ simulation results and the experimental data. A second project regards the CRP focused on benchmark analysis of one of the unprotected passive safety demonstration tests performed at the Fast Flux Test Facility (FFTF), the Loss of Flow Without Scram (LOFWOS) Test #13, started in 2018. A detailed nodalization has been developed by NINE following its nodalization techniques and the NINE validation procedure has been adopted to validate the Simulation Model (SM) against the experimental data of the selected test. The third activity deals with the neutronics benchmark of China Experimental Fast Reactor (CEFR) Start-Up Tests, a CRP proposed by the China Institute of Atomic Energy (CIAE) launched in 2018 the main objective of which is to improve the understanding of the start-up of a SFR and to validate the fast reactor analysis computer codes against CEFR experimental data. A series of start-up tests have been analyzed in this benchmark and NINE also proposed and organized a further work package focused on the sensitivity and uncertainty analysis of the first criticality test. The present chapter intends to summarize the results achieved using the codes currently employed in the field of fast reactor in the framework of international projects and benchmarks in which NINE was involved and emphasize how the application of developed procedures allows to validate the SM results and validate the computer codes against experimental data.
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Ahmad, Imran, Norhayati Abdullah, Shreeshivadasan Chelliapan, Ali Yuzir, Iwamoto Koji, Anas Al-Dailami, and Thilagavathi Arumugham. "Effectiveness of Anaerobic Technologies in the Treatment of Landfill Leachate." In Solid Waste Management [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94741.
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Improper Solid Waste Management leads to the generation of landfill leachate at the landfills. To reduce the negative impacts of highly toxic and recalcitrant leachate on the environment, several techniques have been used. A lot of research is conducted to find suitable methods for the treatment of landfill leachate such as biological processes, chemical oxidation processes, coagulation, flocculation, chemical precipitation, and membrane procedures. The biological process is still being used widely for the treatment of leachate. The current system of leachate treatment consists of various unit processes which require larger area, energy and cost. In addition, the current aerobic treatment is not able to treat entirely the pollutants which require further treatment of the leachate. Anaerobic wastewater treatment has gained considerable attention among researchers and sanitary engineers primarily due to its economic advantages over conventional aerobic methods. The major advantages of anaerobic wastewater treatment in comparison to aerobic methods are: (a) the lack of aeration, which decreases costs and energy requirements; and (b) simple maintenance and control, which eliminates the need for skilled operators and manufacturers. Several anaerobic processes have been used for leachate treatment such as up-flow anaerobic sludge blanket (UASB) reactor, anaerobic filter, hybrid bed reactor, anaerobic sequencing batch reactor and Anaerobic baffled reactor. The following chapter provides an insight to the solid waste management at the landfills, generation of leachate and details of some of the highly efficient anaerobic treatment systems that are used for the overall treatment of landfill leachate.
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PINEDA-PRADO, Daniel Alejandro, and Jaqueline MARMOLEJO-QUINTANAR. "Prototipo de modulo para saneamiento de aguas servidas para reutilizarlas en edificaciones sustentables." In Arquitectura y Sustentabilidad Handbook T-I, 46–52. ECORFAN-Mexico, S.C., 2021. http://dx.doi.org/10.35429/h.2021.14.1.46.52.
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The lack of water in the sectors is synonymous with poverty, health problems, social disorders and conflicts between inhabitants, which can be summarized in what is commonly defined as a low quality of life, since human beings have basic needs that must be satisfied to subsist and fulfill their daily tasks. The capture process in natural sources for the populations that demand it and the distribution networks, is limited in terms of capacity and years of service due to its characteristics that were defined at the time of its design and construction. The increase in the population, the deterioration of the materials and the misuse of the facilities, frequently provoke the modification or implementation of new distribution networks, in communities in which the drinking water service has become precarious. The uses of drinking water are constantly converted into sewage, which makes us reflect on the impact that this generates on the environment, the economy and health, that is why it is desired to implement the treatment of sewage in the place, with treatment processes of traditional, conventional, alternative and natural systems. Goals - Design a reactor module for the treatment of sewage in situ, merging and adapting alternative systems in a simple, practical, economical, small-scale, low-energy consumption and accessible way. - Calculate the initial flow rate and the dimensions of each of its parts, anticipating a volume gap in its capacity of admission. - Have the place to implement the constructive proposal of the module. - Use natural and regional filters to benefit the family economy. - Build an accessible and functional treatment module that complies with current regulations.
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Atkins, Peter. "The Generation Game: Electrochemistry." In Reactions. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199695126.003.0011.
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You already know, if you have read Reaction 6, that an electric current is a stream of electrons. If you have also read the section on redox reactions (Reaction 5), which you should, in preparation for this account, then you will also know that in a redox reaction electrons are transferred from one species to another. Although it is now far too late, had you had that information 150 or so years ago, then you might have realized that if those species were at the opposite ends of a piece of wire, the transfer of electrons would then take place in the form of an electric current travelling along the wire and you would have invented the electric battery. All the batteries that are used to generate electricity and drive portable electrical and electronic equipment, from torches, drills, phones, music players, laptops, through to electric vehicles, are driven by this kind of chemically produced flow of electrons. One of the earliest devices for producing a steady electric current was the ‘Daniell cell’, which was invented in 1836 by John Daniell (1790–1845) of King’s College, London in response to the demand in the nineteenth century of the then emerging technology of telecommunication for a steady, cheap source of electricity. I have already touched on the underlying reaction when I explained what happens when a piece of zinc, Zn, is dropped into a solution of copper sulfate (Reaction 5), and this section builds on that account. In that reaction copper is deposited on the zinc and the copper sulfate solution gradually loses its colour as blue Cu2+ ions are replaced by colourless Zn2+ ions. As this reaction takes place, electrons hop from the zinc metal onto Cu2+ ions nearby in the solution. If we were to stand there watching, we would see electrons snapping across from the zinc to the Cu2+ ions wherever the latter came within striking distance of the zinc surface. There would be electron transfer, but no net current of electricity. Daniell did what I outlined in the opening paragraph: he separated the zinc metal and copper ions, so that electrons released by zinc had to travel through an external wire to get to the Cu2+ ions.
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C. Botar-Jid, Claudiu, Paul Ş. Agachi, and Davide Fissore. "Comparison of reverse flow and counter-current reactors in case of selective catalytic reduction of Nox." In Computer Aided Chemical Engineering, 1331–36. Elsevier, 2007. http://dx.doi.org/10.1016/s1570-7946(07)80246-x.
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Graves, Steven W., and John P. Nolan. "Molecular Assemblies, Probes, and Proteomics in Flow Cytometry." In Flow Cytometry for Biotechnology. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195183146.003.0013.
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The many proteins and nucleic acids encoded in the genome predominantly perform their functions as macromolecular assemblies. In fact, modern biomedical research often targets the interactions of individual molecules of these assemblies, usually by disrupting or enhancing specific contacts, to provide treatment for many different diseases. Therefore, efficient pharmaceutical design requires knowledge of how macromolecular assemblies are built and function. To achieve this goal, sensitive and quantitative tools are essential. This chapter will discuss the use of flow cytometry as a general platform for sensitive measurement and quantification of molecular assemblies. First, this chapter will introduce general methods for analysis of molecular interactions along with a comparison of flow cytometry with these methods. Second, an overview of current flow cytometry instrumentation, assay technologies, and applications in molecular assembly analysis will be given. Third, the implementation of the above approaches in molecular assembly will be discussed. Finally, potential future directions of flow cytometry in molecular assembly analysis will be explored. At present, the analysis of macromolecular assemblies is performed by a wide variety of techniques that are chosen for the target molecules under study (proteins, DNA, lipids, etc.), the type of measurement required (kinetic or equilibrium), and whether the assembly of interest needs to be studied in vivo or in vitro. This continuum of techniques can be divided into the heterogeneous assays, which require a separation step to resolve products from reactants, and homogeneous assays, which can measure interactions without a separation step. Heterogeneous assays, in general, use radioisotopes, which are not perturbing; offer excellent sensitivity; and provide accurate quantification. The products are quantified after a separation step such as gel filtration, gel electrophoresis, or centrifugation. Rapid quench methods can provide subsecond kinetic resolution; however, the added separation steps are tedious and make collection of kinetic time courses difficult, as each time point must be separated and measured individually. Furthermore, in the time it takes the separation to occur, the interaction of interest can dissociate, which is a problem specific to low-affinity assemblies. Nonetheless, by using rapid chemical quench techniques, reaction times as short as a few milliseconds can be observed. Homogenous assays can be separated into solution- or surface-based assays. Solutionbased assays measure an optical signal generated by the assembly to quantify an interaction. High component concentrations (micromolar) allow changes in intrinsic molecular properties, such as protein fluorescence or circular dichroism, to be used to study molecular assemblies. For greater sensitivity (nanomole component concentrations), resonance energy transfer or polarization assays using exogenous fluorescent labels can be used. In combination with stopped-flow spectroscopy methodologies, solution-based assays allow reactions to monitored in a continuous fashion with submillisecond dead times.
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Millar, Dean L. "Wave and tidal power." In Energy... beyond oil. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780199209965.003.0006.
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This chapter reviews how electricity can be generated from waves and tides. The UK is an excellent example, as the British Isles have rich wave and tidal resources. The technologies for converting wave power into electricity are easily categorized by location type. 1. Shoreline schemes. Shoreline Wave Energy Converters (WECs) are installed permanently on shorelines, from where the electricity is easily transmitted and may even meet local demands. They operate most continuously in locations with a low tidal range. A disadvantage is that less power is available compared to nearshore resources because energy is lost as waves reach the shore. 2. Nearshore schemes. Nearshore WECs are normally floating structures needing seafloor anchoring or inertial reaction points. The advantages over shoreline WECs are that the energy resource is much larger because nearshore WECs can access long-wavelength waves with greater swell, and the tidal range can be much larger. However, the electricity must be transmitted to the shore, thus raising costs. 3. Offshore schemes. Offshore WECs are typically floating structures that usually rely on inertial reaction points. Tidal range effects are insignificant and there is full access to the incident wave energy resource. However, electricity transmission is even more costly. Tidal power technologies fall into two fundamental categories:1. Barrage schemes. In locations with high tidal range a dam is constructed that creates a basin to impound large volumes of water. Water flows in and out of the basin on flood and ebb tides respectively, passing though high efficiency turbines or sluices or both. The power derives from the potential energy difference in water levels either side of the dam. 2. Tidal current turbines. Tidal current turbines (also known as free flow turbines) harness the kinetic energy of water flowing in rivers, estuaries, and oceans. The physical principles are analogous to wind turbines, allowing for the very different density, viscosity, compressibility, and chemistry of water compared to air. Waves are caused by winds, which in the open ocean are often of gale force (speed >14 m/s).
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Ali, Rashid. "Low Melting Mixture of L-(+)-Tartaric Acid and N,N′-Dimethyl Urea: A New Arrival in the Green Organic Synthesis." In Current Topics in Chirality - From Chemistry to Biology. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.97392.
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After the first report of deep eutectic mixtures by the team of Abbott in 2003, the advent of green synthesis has been progressively changing the way synthetic chemistry is thought and also taught. Since then, a plethora of efforts worldwide have been taken to stretch the ideas of sustainable as well as environmentally benign approaches to do the crucial synthetic organic transformations under operationally simple yet effective conditions. Although, till date, several green synthetic strategies for examples ultrasound, microwaves, flow as well as grindstone chemistry etc., and green reaction media (e.g. ionic liquid, water, scCO2, and so forth) have successfully been invented. But a low melting mixture of L-(+)-tartaric acid (TA) and N,N′-dimethylurea (DMU), usually plays a double and/or triple role (solvent, catalyst, and/or reagent), though still infancy but enjoys several eye-catching properties like biodegradability, recyclability, non-toxicity, good thermal stability, tunable physiochemical properties, low vapor pressure as well as reasonable prices in addition to the easy preparation with wide functional groups tolerance. To this context, keeping the importance of this novel low melting mixture in mind, we intended to reveal the advancements taken place in this wonderful area of research since its first report by the Köenig’s group in 2011 to till date. In this particular chapter, firstly we would disclose the importance of the green synthesis followed by a brief description of deep-eutectic solvents (DESs) particularly emphasizing on the role of L-(+)-TA and DMU from modern synthetic chemistry perspective.
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R. Nartissov, Yaroslav. "Amino Acids as Neurotransmitters. The Balance between Excitation and Inhibition as a Background for Future Clinical Applications." In Recent Advances in Neurochemistry [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103760.
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For more than 30 years, amino acids have been well-known (and essential) participants in neurotransmission. They act as both neuromediators and metabolites in nervous tissue. Glycine and glutamic acid (glutamate) are prominent examples. These amino acids are agonists of inhibitory and excitatory membrane receptors, respectively. Moreover, they play essential roles in metabolic pathways and energy transformation in neurons and astrocytes. Despite their obvious effects on the brain, their potential role in therapeutic methods remains uncertain in clinical practice. In the current chapter, a comparison of the crosstalk between these two systems, which are responsible for excitation and inhibition in neurons, is presented. The interactions are discussed at the metabolic, receptor, and transport levels. Reaction-diffusion and a convectional flow into the interstitial fluid create a balanced distribution of glycine and glutamate. Indeed, the neurons’ final physiological state is a result of a balance between the excitatory and inhibitory influences. However, changes to the glycine and/or glutamate pools under pathological conditions can alter the state of nervous tissue. Thus, new therapies for various diseases may be developed on the basis of amino acid medication.
Тези доповідей конференцій з теми "Current flow reactor"
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Huang, Wei, Eric Million, Kelvin Randhir, Joerg Petrasch, James Klausner, Nick AuYeung, and Like Li. "Heat Transfer Modeling in a Counter-Current Moving-Bed Tubular Reactor for High-Temperature Thermochemical Energy Storage." In ASME 2021 15th International Conference on Energy Sustainability collocated with the ASME 2021 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/es2021-63490.
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Abstract An axisymmetric model coupling counter-current gas-solid flow, heat transfer, and thermochemical redox reactions in a moving-bed tubular reactor was developed. The counter-current flow enhances convective heat transfer and a low oxygen partial pressure environment is maintained for thermal reduction within the reaction zone by using oxygen depleted inlet gas. A similar concept can be used for the oxidation reactor which releases high-temperature heat that can be used for power generation or as process heat. The heat transfer model was validated with published results for packed bed reactors. After validation, the model was applied to simulate the moving-bed reactor performance, through which the effects of the main geometric parameters and operating conditions were studied to provide guidance for lab-scale reactor fabrication and testing.
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Tekavčič, Matej, Boštjan Končar, and Ivo Kljenak. "Simulation of Counter-Current Gas-Liquid Churn Flow." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17664.
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A transient simulation of air-water counter-current flow by the means of two-fluid model with interface sharpening is performed. The gas-liquid inhomogeneous model with both phases considered as incompressible is used. Turbulence is modelled for each phase separately using the two-equation eddy viscosity model. The numerical domain consists of an axisymmetric wedge with the porous wall inlet region representing a vertical pipe experimental test section. Evolution of volume fraction, velocities and pressure variations along the interface is presented. Simulation results are compared with the known experimental data (from the literature) for the wave frequency and velocity. The present simulation is also compared to a known numerical simulation found in literature that used volume of fluid method. Sensitivity study of several modelling parameters is performed to evaluate and discuss their impact on simulation results in an attempt to establish best practice guidelines for modelling of realistic counter-current flows, important in nuclear reactor systems.
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Selimovic, Faruk, Tor Bruun, and Bengt Sunde´n. "Computational Analysis of Gas Flow and Heat Transport Phenomena in Monolithic Structures for High Temperature Processes." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72183.
Повний текст джерелаАнотація:
High-temperature catalytic processes such as partial oxidation of Methane (POX) and steam Methane reforming (SMR) may benefit from use of reactor systems using monolithic honeycomb structures. Hereby, process performance is enhanced through more efficient heat transfer and considerable smaller reactor foot-prints than for conventional reactor concepts. Compact ceramic heat exchange structures may also be an interesting option for increasing the energy efficiency of high temperature processes in general. One example is single cycle turbines where these structures can be used as recuperators. The purpose of this paper is to describe modelling of gas flow pattern and heat transfer in reactors and heat exchangers with monolithic based structures. This technology is currently under development in a partnership of European companies and academia, with financial support from the EC and Swiss Government. The mathematical model developed for heat transfer and flow maldistribution has been used for counter-current checkerboard channel-arrangement. Pressure drop has been analyzed both experimentally and numerically (computation fluid dynamics, CFD). Power density has been shown to depend on various reactor parameters. Channel geometry, inlet gas temperature difference and channel wall thickness have been calculated to find the influence on power density.
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Sirr, Noel, Doina Ciobanu, Ronan Grimes, and Mark Davies. "A Continuous Flow Polymerase Chain Reactor for DNA Expression Analysis." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96180.
Повний текст джерелаАнотація:
The polymerase chain reaction (PCR) has revolutionised molecular biology, and is at the forefront of many current efforts to document and understand human genetic diversity. Recent years has seen a move towards incorporating the PCR technique into a micro Total Analysis System (μTAS) thus exploiting its full potential. Micro scale PCR design offers the opportunity to integrate all functional steps of DNA expression analysis into a miniaturised device allowing for high throughput and reduced analysis times, reduced sample volume requirements and cost efficiency. Consequently, it is desirable to replace the traditional stationary or well based thermal cyclers with continuous flow designs. A continuous flow polymerase chain reaction device consisting of a cylindrical heating core, which is segmented axially into three symmetric heating zones providing the denaturating, annealing and extension phases of the polymerase chain reaction, and a flow through capillary tube which is wound helically around the core has been fabricated and shown to consistently amplify target plasmid DNA samples. At the inlet to the device, PCR samples are segmented into droplets and entrained in an immiscible carrier fluid to eliminate cross contamination between PCR samples. This approach also prevents degradation of the micro-reactor droplets from inhibitory effects posed by the high surface to volume ratios associated with the device. The droplet train is then cycled through the capillary tube with each complete revolution constituting one cycle of the PCR reaction. The results reported in this paper include, initial validation of the spiral cycler design in comparison to an existing commercial PCR platform, and subsequent optimisation of the reaction time and its effects on the devices performance. The spiral thermal cycler has demonstrated successful PCR amplification at the nano scale with stable trains of 30–35nl droplet volumes being processed in an amplification time of 32 minutes. At this level the device offers the potential to process approximately 3500 such droplets in of order one hour.
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Valle´e, Christophe, Deendarlianto, Matthias Beyer, Dirk Lucas, and Helmar Carl. "Air/Water Counter-Current Flow Experiments in a Model of the Hot Leg of a Pressurised Water Reactor." In 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48374.
Повний текст джерелаАнотація:
Different scenarios of small break Loss of Coolant Accident (LOCA) for pressurised water reactors (PWR) lead to the reflux-condenser mode in which steam enters the hot leg from the reactor pressure vessel (RPV) and condenses in the steam generator. A part of the condensate flows back towards the RPV in counter current to the steam. During the reflux-condenser mode, a counter-current flow limitation (CCFL) must be prevented because this would limit the core cooling. The simulation of CCFL conditions, which is dominated by 3D effects, requires the use of a computational fluid dynamics (CFD) approach. These methods are not yet mature and have to be validated before they can be applied to nuclear reactor safety. Therefore, dedicated experimental data is needed with high resolution in space and time. In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, the “hot leg model” was built at Forschungszentrum Dresden-Rossendorf (FZD). This setup is devoted to optical measurement techniques, therefore, a flat test-section design was chosen with a width of 50 mm. The test-section outlines represent the hot leg of a German Konvoi PWR at a scale of 1:3, which corresponds to a channel height of 250 mm in the straight part of the hot leg. The test-section is mounted between two separators, one simulating the reactor pressure vessel and the other is connected to the steam generator inlet chamber. This allows to perform co-current as well as counter-current flow experiments. Moreover, the hot leg model is built in the pressure vessel of the TOPFLOW facility of FZD, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the vessel. Therefore, the test section can be designed with thin materials and equipped with big size windows like in the hot leg model. The presented air/water experiments focus on the flow structure observed in the region of the riser and of the steam generator inlet chamber at room temperature and pressures up to 3 bars. The performed high-speed observations show the evolution of the stratified interface and the distribution of the two-phase mixture (droplet and bubbles). Counter-current flow limitation, or the onset of flooding, was found by analysing the water levels measured in the separators. A confrontation with the images indicates that the initiation of flooding coincides with the reversal of the flow in the horizontal part of the hot leg due to high air velocities. Afterwards, bigger waves are generated, which develop to slugs. Furthermore, the CCFL data was compared with similar experiments and empirical correlations available in the literature. The agreement of the CCFL curve is good and indicate that the data is relevant for CFD validation purposes. The zero penetration was found at lower values of the Wallis parameter than in most of the previous work, which can be attributed to the rectangular geometry of the hot leg model.
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Chen, Pei-Yin, Patrick Sekerak, Thomas Scarbrough, and Cheng-Ih Wu. "Potential Adverse Flow Effects at Nuclear Power Plants." In 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48900.
Повний текст джерелаАнотація:
In recent years, the nuclear industry experienced adverse flow effects that caused structural damage to safety-related and nonsafety-related components as a result of flow-induced acoustic resonance in both Boiling Water Reactor (BWR) and Pressurized Water Reactor plants. In particular, fatigue failures and cracks in steam dryers occurred in certain BWR plants during the extended power uprate operation with generation of loose parts that can adversely affect safety-related components within the reactor vessel and the reactor coolant system. The acoustic resonance occurs when the main steam line flow exceeds a critical value such that the vortices over the cavity of the closed side branch pipe are excited by the acoustic modes of the stagnant fluid in the branch. The occurrence of this phenomenon is highly dependent on plant-specific operating conditions and the piping as-built configuration. The U.S. nuclear industry has initiated extensive activities to address this phenomenon in BWR plants. The staff of the U.S. Nuclear Regulatory Commission (NRC) has been monitoring generic industry activities, as well as reviewing the evaluation of potential adverse flow effects that might result from power uprates at current operating plants, and during the design certification and licensing of new reactors. This paper discusses operating experience with adverse flow effects at nuclear power plants from the acoustic resonance phenomenon, industry actions to address and resolve the phenomenon, and NRC staff review activities related to this issue.
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Oh, Chang H., and Eung S. Kim. "Validations of CFD Code for Density-Gradient Driven Air Ingress Stratified Flow." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29807.
Повний текст джерелаАнотація:
Air ingress into a very high temperature gas-cooled reactor (VHTR) is an important phenomenon to consider because the air oxidizes the reactor core and lower plenum where the graphite structure supports the core region in the gas turbine modular helium reactor (GT-MHR) design, thus jeopardizing the reactor’s safety. Validating the computational fluid dynamics (CFD) code used to analyze the air ingress phenomena is therefore an essential part of the safety analysis and the ultimate computation required for licensing. An experimental data set collected by ETH Zurich on a lock exchange experiment (Grobelbauser et al., Lowe et al. 2002; Lowe et al. 2005; and Shin et al. 2004) was selected for the validation. The experiment was based on a series of lock exchange flows with gases of different density ratios varying from 0.046 to 0.9 in a closed channel of a square cross-section. The focus was on the quantitative measurement of front velocities of the gravity current flows. The experiment results cover the full range of gas intrusions—heavy as well as light—for the gravity current flows in the lock exchange situations. FLUENT CFD code (ANSYS Fluent 2008) was used. The calculated results showed very good agreement with the experimental data. A number of tables and comparison plots are included to summarize the estimated current speeds. The current speed obtained by experimental data was 1.25 m/s and that of the simulation was 1.19 m/s. This result indicates that the deviation of the simulation is only 4.8% that of the experimental data.
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Liu, Jiawei, Puzhen Gao, Tingting Xu, Jiesheng Min, and Guofei Chen. "Numerical Simulation of Flow Field Inside Reactor Upper Plenum for PWR With Code_Saturne." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-68008.
Повний текст джерелаАнотація:
Flow characteristic in upper plenum has a strong influence on reactor functional margin and rod cluster control assembly (RCCA) guide tube wear. Upper plenum flow governs loops flow rate measurement via hot leg temperature which has also an influence on the reactor protection system. For RCCA guide tube wear, it appears in operation with RCCA flow-induced vibration, leading to its replacement. It is important to know the flow condition in the upper plenum, and in particular the outlet. Existing Generation III reactors have their own specialties on the design. Comparison between current technologies is a good way for better understanding on the key structure design for the upper plenum. In this paper, simplified models based on upper plenum structure of Korean advanced pressurized water reactor (PWR) and Westinghouse design AP1000 are constructed and meshed with a volume around 6 million cells to obtain a 3-dimensional global and local flow distributions inside the upper plenum and to characterize the vital flow features for reactor safety. The Navier-Stokes equations are solved with standard k-ε turbulence model by using EDF in-house open source computational fluid dynamic (CFD) software: Code_Saturne. Through calculations, pressure and velocity distributions are obtained, axial and lateral variations have been analyzed. Compared with APR1400, it can be observed that for the design of AP1000, the rotational flow entrained in the edge of upper plenum and high velocity area due to the hot leg suction effect contribute to the relatively lower local pressure, and may have an impact on the drop velocity of control rod.
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Sebilleau, Frederic, Anuj K. Kansal, Raad I. Issa, and Simon P. Walker. "CFD Analysis of Single Phase Counter-Current Buoyancy Driven Flows and its Applications to Passive Reactor Design." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-31264.
Повний текст джерелаАнотація:
Increasingly, nuclear plants rely on natural circulation, for both fault conditions and / or normal power removal. Prediction of such buoyancy-driven flows is needed. However, their complex nature leads to 3D effects in ‘wide’ geometries, making prediction impossible with system codes. Even in slender “pipe-like” geometries countercurrent flow of hot and cold fluid makes a one-dimensional simulation totally misleading. However, simply moving to a three-dimensional CFD treatment is not sufficient. The strong anisotropy of the turbulence and the coexistence of various flow regimes make the choice of an appropriate turbulence model difficult. Countercurrent flow in a pipe might occur when the “natural” buoyant flow was of hot fluid up the pipe, but a feature such as a local heat-sink (an un-insulated valve in the pipe, perhaps) acts as a source of cold fluid, which attempts to flow down the pipe as a counter-current flow. On a different scale, counter current flow such as this would occur for example inside the secondary containment. This countercurrent flow problem captures the complexities of most buoyant flows, and this provides a challenging model problem. In this paper, we describe the design and preliminary analysis of an experimental rig being built to study this. Initial CFD and experimental results are presented.
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Takase, Kazuyuki, Hiep H. Nguyen, Gaku Takase, and Yoshihisa Hiraki. "Behavior of Bubbles Separated by a Cross-Shaped Obstacle Placed in a Circular Flow Channel." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71810.
Повний текст джерелаАнотація:
Clarifying two-phase flow characteristics in a nuclear reactor core is important in particular to enhance the thermo-fluid safety of nuclear reactors. Moreover, bubbly flow data in subchannels with spacers are needed as validation data for current CFD codes like a direct two-phase flow analysis code. In order to investigate the spacer effect on the bubbly flow behavior in a subchannel of the nuclear reactor, bubble dynamics around the simply simulated spacer was visually observed by a high speed camera. Furthermore, the void fraction and interfacial velocity distributions just behind the simulated spacer were measured quantitatively by using a wire-mesh sensor system with three wire-layers in the flow direction. From the present study, bubble separation behavior dependence upon the spacer shape was clarified.
Звіти організацій з теми "Current flow reactor"
1
Cetiner, Sacit, Kellen Oleksak, Bruce Warmack, Michael Roberts, Milton Ericson, and Aly Fathy. Preliminary Design Study for an Eddy Current Flow Meter for Versatile Test Reactor. Office of Scientific and Technical Information (OSTI), June 2019. http://dx.doi.org/10.2172/1543198.
Повний текст джерела
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Hess, Mark, and Evstati Evstatiev. Effects of Radiation Reaction Physics on High-Current Power Flow. Office of Scientific and Technical Information (OSTI), August 2021. http://dx.doi.org/10.2172/1814239.
Повний текст джерела
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Rudyk, Myroslava. COMMUNICATIVE FEATURES OF UKRAINIAN VIDEO BLOGS ON THE EXAMPLE OF YOUTUBE-CHANNELS OF «TORONTO TV», YANINA SOKOLOVA, AND OSTAP DROZDOV. Ivan Franko National University of Lviv, March 2021. http://dx.doi.org/10.30970/vjo.2021.50.11111.
Повний текст джерелаАнотація:
The article is devoted to the study of the Ukrainian segment of video blogging as one of the most popular types of the functioning of the modern blogosphere. The content and statistics of popular video blogs were studied on the example of YouTube channels of Ukrainian bloggers and famous journalists. Today we are witnessing the rapid development of technologies that help journalists become better, and the creators of media content to work more quickly and ensure the completeness of the information. With the help of Internet communication, new ways of disseminating information have appeared in journalism. Journalists more often create their blogs on various platforms. Blogosphere video content has become very popular among the Ukrainian audience on YouTube because today the video format is the most effective in terms of communication. The YouTube social network partially replaces television, and the variety of thematic content is ably adapted to a wide audience. The paper analyzes Ukrainian blogs managed by journalists, where they publish different content formats. Therefore, the presentation of various examples of video blogs in our work helps to understand the specifics of Ukrainian blogging at its current stage of development. After all, videos of popular people such as Michael Shchur, Yanina Sokolova, Ostap Drozdov demonstrate the peculiarities of Ukrainian popular video content. For the research, we chose those blogs that are currently relevant to Ukrainian YouTube and have their specifics and uniqueness. The main objective of a blogger is to react quickly to the flow of information because the rating of the channel being monetized depends on it. With the help of statistical data, we can conclude that the Ukrainian audience is interested in a wide range of different information. Viewers now value the independent opinion of bloggers and more often listen to it. Every important event is covered by bloggers promptly. And the format in which it is presented depends on the individual style of the author and the concept of his channel. We can conclude that the video content of the modern blogosphere is developing rapidly. This provides the audience with information for different tastes.