scholarly journals Influence of Thermal Conditions on Particle Properties in Fluidized Bed Layering Granulation

Processes ◽  
2018 ◽  
Vol 6 (12) ◽  
pp. 235 ◽  
Author(s):  
Christoph Neugebauer ◽  
Andreas Bück ◽  
Stefan Palis ◽  
Lisa Mielke ◽  
Evangelos Tsotsas ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Dynamic Model ◽  
Mutual Influence ◽  
Thermal Conditions ◽  
Balance Model ◽  
Particle Sizes ◽  
Particle Properties ◽  
Experimental Findings ◽  
Fluidized Particles ◽  
First Time

Fluidized bed layering granulation is frequently used to formulate particles of high quality. From previous studies, it is well known that the dynamic behavior of the process, as well as the product properties depend on operating parameters. The process is characterized by heat and mass transfer between fluidized particles and the surrounding fluidization medium. To investigate the mutual influence between particle phase and fluidization medium, a dynamic model is introduced. The model comprises two parts: a population balance model to describe the evolution of the particle sizes and a system of ordinary differential equations to account for thermal conditions. For the first time, the dynamic model considers the bidirectional coupling of particles and fluidization medium in fluidized bed layering granulation. By means of simulations, it is shown that the derived model is capable of reproducing the experimental findings.

Self-Regulation and Human Progress

2018 ◽  
Author(s):  
Evan Osborne
Keyword(s):  
Scientific Method ◽  
Mutual Influence ◽  
Free Market ◽  
Self Regulation ◽  
Free Expression ◽  
Trial And Error ◽  
Human History ◽  
Economic Context ◽  
The Right ◽  
First Time

Does humanity progress primarily through leaders organizing and directing followers, or through trial and error by individuals free to chart their own path? For most of human history ruling classes had the capacity and the desire to tightly regiment society, to the general detriment of progress. But beginning in the 1500s, Europeans developed a series of arguments for simply leaving well enough alone. First in the form of the scientific method, then in the form of free expression, and finally in the form of the continuously, spontaneously reordered free market, people began to accept that progress is hard, and requires that an immense number of mistakes be tolerated so that we may learn from them. This book tells the story of the development of these three ideas, and for the first time tells of the mutual influence among them. It outlines the rise, and dramatic triumph, of each of these self-regulating systems, followed by a surprising rise in skepticism, especially in the economic context. Such skepticism in the 20th century was frequently costly and sometimes catastrophic. Under the right conditions, which are more frequent than generally believed, self-regulating systems in which participants organize themselves are superior. We should accept their turbulence in exchange for the immense progress they generate.

Development of a Heat-Balance Model for a Fluidized Bed Waste Gasification Furnace

2004 ◽  
Vol 30 (4) ◽  
pp. 447-454
Author(s):  
Takahiro MARUMOTO ◽  
Naoki FUJIWARA ◽  
Noriyuki OHYATSU ◽  
Tetsuya IWASE
Keyword(s):  
Fluidized Bed ◽  
Heat Balance ◽  
Balance Model ◽  
Waste Gasification

scholarly journals Polarizability-dependent Sorting of Microparticles Using Continuous-flow Dielectrophoretic Chromatography with a Frequency Modulation Method

2019 ◽  
Author(s):  
Jasper Giesler ◽  
Georg R. Pesch ◽  
Laura Weirauch ◽  
Marc-Peter Schmidt ◽  
Jorg Thöming ◽  
...  
Keyword(s):  
Chromatographic Separation ◽  
Continuous Flow ◽  
Research Field ◽  
Modulation Method ◽  
Particle Sizes ◽  
Frequency Bandwidth ◽  
New Approach ◽  
Particle Properties ◽  
Multiple Particle ◽  
Multiple Trap And Release

The separation of microparticles with respect to different properties such as size and material is a research field of great interest. Dielectrophoresis, a phenomenon which is capable of addressing multiple particle properties at once, can be used to perform a chromatographic separation. However, the selectivity of current dielectrophoretic particle chromatography (DPC) techniques is limited. Here we show a new approach for DPC based on differences in the dielectrophoretic mobilities and the crossover frequencies of polystyrene particles. Both differences are addressed by modulating the frequency of the electric field to generate positive and negative dielectrophoretic movement to achieve multiple trap and release cycles of the particles. A chromatographic separation of different particle sizes revealed a voltage dependency of this method. Additionally, we showed the frequency bandwidth influence on separation using one example. The DPC method developed was tested with model particles but offers possibilities to separate a broad range of plastic and metal microparticles or cells and to overcome currently existing limitations in selectivity.

scholarly journals On microphysical processes of noctilucent clouds (NLC): observations and modeling of mean and width of the particle size-distribution

2010 ◽  
Vol 10 (2) ◽  
pp. 3605-3625
Author(s):  
G. Baumgarten ◽  
J. Fiedler ◽  
M. Rapp
Keyword(s):  
Particle Size ◽  
Linear Relationship ◽  
Size Distribution ◽  
Eddy Diffusion ◽  
Particle Sizes ◽  
Noctilucent Clouds ◽  
Atmospheric Variability ◽  
Distribution Width ◽  
Particle Properties ◽  
Microphysical Processes

Abstract. Noctilucent clouds (NLC) in the polar summer mesopause region have been observed in Norway (69° N, 16° E) between 1998 and 2009 by 3-color lidar technique. Assuming a mono-modal Gaussian size distribution we deduce mean and width of the particle sizes throughout the clouds. We observe a quasi linear relationship between distribution width and mean of the particle size at the top of the clouds and a deviation from this behavior for particle sizes larger than 40 nm, most often in the lower part of the layer. The vertically integrated particle properties show that 65% of the data follows the linear relationship with a slope of 0.42±0.02. For the vertically resolved particle properties (Δz=0.15 km) the slope is smaller and only 0.39±0.03. We compare our observations to microphysical modeling of noctilucent clouds and find that the distribution width depends on turbulence, the time that turbulence can act (cloud age), and the sampling volume/time (atmospheric variability). The model results nicely reproduce the measurements and show that the observed slope can be explained by eddy diffusion profiles as observed from rocket measurements.

Study of the biocompatibility of lactic acid bacteria and other microorganisms-antagonists isolated from natural sources

2021 ◽  
pp. 40-42
Author(s):  
Светлана Юрьевна Носкова ◽  
Мария Игоревна Зимина ◽  
Ольга Олеговна Бабич ◽  
Станислав Алексеевич Сухих ◽  
Александр Юрьевич Просеков ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Mutual Influence ◽  
Growth Characteristics ◽  
Natural Sources ◽  
Urgent Task ◽  
First Time

Изучение биосовместимости молочнокислых бактерий и других микроорганизмов-антагонистов, выделенных из природных источников, является актуальной задачей. В данной работе впервые показано взаимное влияние изолятов молочно-кислых бактерий и других микроорганизмов-антагонистов при совместном культивировании. Установлено, что изолят 1 является биосовместимым с изолятами 6, 13, 19 и 20. Изолят 6 активно растет в присутствии изолятов 7, 8, 9, 10, 11, 13 и 16. Изолят 7 биосовместим с изолятами 6, 8, 9, 10, 11, 12, 13, 16, изолят 8 является биосовместимым с изолятами 6, 7, 9, 10, 11, 13 и 16. Для изолята 9 наблюдается биосовместимость с изолятами 6, 7, 8, 10, 11, 12, 13, 16, для изолята 10 - с изолятами 6, 7, 8, 9, 11, 13, 16. Изолят 11 показывает удовлетворительные ростовые характеристики при совместном культивировании с изолятами 6, 7, 8, 9, 10, 12, 13, 16. Изолят 12 биосовместим с изолятами 7, 8, 9, 10, 11, 13 и 16. Изолят 13 является биосовместимым с изолятами 6, 7, 8, 9, 10, 11, 12, 16. Изолят 16 биосовместим с изолятами 6, 7, 8, 9, 10, 11, 12, 13. Изолят 19 является биосовместимым с изолятами 1, 6, 13 и 20, изолят 20 - с изолятами 1, 6, 13 и 19. Полученные результаты позволяют сделать вывод о том, что изоляты 1, 6, 19 и 20 являются близкородственными, так же как изоляты 7, 8, 9, 10, 11, 12, 13 и 16. The study of the biocompatibility of lactic acid bacteria and other antagonist microorganisms isolated from natural sources is an urgent task. This work shows for the first time the mutual influence of isolates of lactic acid bacteria and other microorganisms-antagonists during co-cultivation. It was found that isolate 1 is biocompatible with isolates 6, 13, 19, and 20. Isolate 6 actively grows in the presence of isolates 7, 8, 9, 10, 11, 13, and 16. Isolate 7 is biocompatible with isolates 6, 8, 9, 10 , 11, 12, 13, 16, isolate 8 is biocompatible with isolates 6, 7, 9, 10, 11, 13 and 16. Isolate 9 is biocompatible with isolates 6, 7, 8, 10, 11, 12, 13, 16, for isolate 10 - with isolates 6, 7, 8, 9, 11, 13, 16. Isolate 11 shows satisfactory growth characteristics when co-cultivated with isolates 6, 7, 8, 9, 10, 12, 13, 16. Isolate 12 is biocompatible with isolates 7, 8, 9, 10, 11, 13 and 16. Isolate 13 is biocompatible with isolates 6, 7, 8, 9, 10, 11, 12, 16. Isolate 16 is biocompatible with isolates 6, 7, 8 , 9, 10, 11, 12, 13. Isolate 19 is biocompatible with isolates 1, 6, 13 and 20, isolate 20 - with isolates 1, 6, 13, and 19. The results obtained suggest that isolates 1, 6, 19 and 20 are closely related as well as isolates 7, 8, 9, 10, 11, 1 2, 13 and 16.

Modelling Semi-Solid Behaviour and Brittle Temperature Range

2019 ◽  
Vol 285 ◽  
pp. 361-366 ◽  
Author(s):  
Khalil Traidi ◽  
Véronique Favier ◽  
Philippe Lestriez ◽  
Karl Debray ◽  
Laurent Langlois ◽  
...  
Keyword(s):  
Solid State ◽  
Material Properties ◽  
Solid Phase ◽  
Thermal Conditions ◽  
Tensile Tests ◽  
Internal Variable ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Semi Solid ◽  
First Time

In this paper, a new elastic viscoplastic micromechanical modelling is proposed to represent the semi-solid behaviour and predict the ductile-brittle transition of the C38LTT near the solidus. It is based on a viscoplastic modelling previously presented in [1]. The originality of the new model comes from three main enhancements: the transition between the solid state and the semi-solid state was included meaning that the material properties were taken temperature-dependent, the elastic properties was taken into account similarly as [2] and the evolution of the internal variable describing the degree of agglomeration of the solid phase was enhanced. The model was implemented in the commercial software FORGE©. Tensile tests representing the experimental thermal conditions and obtained using a GLEEBLE© machine were simulated. The comparison of the predicted and experimental results shows that, for the first time to our knowledge, the three steps of the load-displacement response and ductile-brittle transition were successfully described.

scholarly journals A dynamic model of fluidized-bed flotation

2019 ◽  
Vol 52 (14) ◽  
pp. 66-71
Author(s):  
David Georges-Filteau ◽  
Jocelyn Bouchard ◽  
André Desbiens
Keyword(s):  
Fluidized Bed ◽  
Dynamic Model

scholarly journals CFD-PBM Coupled Simulation of Liquid-Liquid Dispersions in Spray Fluidized Bed Extractor: Comparison of Three Numerical Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Dan Zheng ◽  
Wei Zou ◽  
Chuanfeng Peng ◽  
Yuhang Fu ◽  
Jie Yan ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Method Of Moments ◽  
Chemical Engineering ◽  
High Reliability ◽  
Scale Up ◽  
Population Balance ◽  
Numerical Code ◽  
Balance Model ◽  
Quadrature Method ◽  
Quadrature Method Of Moments

A coupled numerical code of the Euler-Euler model and the population balance model (PBM) of the liquid-liquid dispersions in a spray fluidized bed extractor (SFBE) has been performed to investigate the hydrodynamic behavior. A classes method (CM) and two representatively numerical moment-based methods, namely, a quadrature method of moments (QMOM) and a direct quadrature method of moments (DQMOM), are used to solve the PBE for evaluating the effect of the numerical method. The purpose of this article is to compare the results achieved by three methods for solving population balance during liquid-liquid two-phase mixing in a SFBE. The predicted results reveal that the CM has the advantage of computing the droplet size distribution (DSD) directly, but it is computationally expensive if a large number of intervals are needed. The MOMs (QMOM and DQMOM) are preferable to coupling the PBE solution with CFD codes for liquid-liquid dispersions simulations due to their easy application, reasonable accuracy, and high reliability. Comparative results demonstrated the suitability of the DQMOM for modeling the spray fluidized bed extractor with simultaneous droplet breakage and aggregation. This work increases the understanding of the chemical engineering characteristics of multiphase systems and provides a theoretical basis for the quantitative design, scale-up, and optimization of multiphase devices.

Patterns of Locomotor Drive to Motoneurons and Last-Order Interneurons: Clues to the Structure of the CPG

2001 ◽  
Vol 86 (1) ◽  
pp. 447-462 ◽  
Author(s):  
R. E. Burke ◽  
A. M. Degtyarenko ◽  
E. S. Simon
Keyword(s):  
Fictive Locomotion ◽  
Cutaneous Reflex ◽  
Reflex Pathways ◽  
Locomotor Control ◽  
Low Threshold ◽  
Experimental Findings ◽  
Differential Control ◽  
Flexor Digitorum ◽  
First Time ◽  
Shed Light

We have examined the linkage between patterns of activity in several hindlimb motor pools and the modulation of oligosynaptic cutaneous reflex pathways during fictive locomotion in decerebrate unanesthetized cats to assess the notion that such linkages can shed light on the structure of the central pattern generator (CPG) for locomotion. We have concentrated attention on the cutaneous reflex pathways that project to the flexor digitorum longus (FDL) motor pool because of that muscle's unique variable behavior during normal and fictive locomotion in the cat. Differential locomotor control of last-order excitatory interneurons in pathways from low-threshold cutaneous afferents in the superficial peroneal and medial plantar afferents to FDL motoneurons is fully documented for the first time. The qualitative patterns of differential control are shown to remain the same whether the FDL muscle is active in early flexion, as usually found, or during the extension phase of fictive locomotion, which is less common during fictive stepping. The patterns of motor pool activity and of reflex pathway modulation indicate that the flexion phase of fictive locomotion has distinct early versus late components. Observations during “normal” and unusual patterns of fictive stepping suggest that some aspects of locomotor pattern formation can be separated from rhythm generation, implying that these two CPG functions may be embodied, at least in part, in distinct neural organizations. The results are discussed in relation to a provisional circuit diagram that could explain the experimental findings.

scholarly journals Physicochemical, Rheological, and Morphological Characteristics of Products from Traditional and Extrusion Nixtamalization Processes and Their Relation to Starch

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Carlos Martín Enríquez-Castro ◽  
Patricia Isabel Torres-Chávez ◽  
Benjamín Ramírez-Wong ◽  
Armando Quintero-Ramos ◽  
Ana Irene Ledesma-Osuna ◽  
...  
Keyword(s):  
Resistant Starch ◽  
Morphological Characteristics ◽  
Extrusion Process ◽  
Quality Parameter ◽  
Particle Sizes ◽  
Corn Flour ◽  
Viscoelastic Parameters ◽  
Size Index ◽  
Parameter Values ◽  
First Time

The aim of this study was to compare the physicochemical, rheological, and morphological characteristics of corn, nixtamalized flour, masa, and tortillas from the traditional nixtamalization process (TNP) and the extrusion nixtamalization process (ENP) and their relationship with starch. The traditional and extrusion processes were carried out using the same variety of corn. From both processes, samples of ground corn, nixtamalized flour, masa, and tortillas were obtained. The extrusion process produced corn flour with particle sizes smaller (particle size index, PSI = 51) than that of flour produced by the traditional nixtamalization process (PSI = 44). Masa from the TNP showed higher modulus of elasticity (G′) and viscosity (G″) values than that off masa from the ENP. Furthermore, in a temperature sweep test, masa from the TNP showed a peak in G′ and G″, while the masa from the ENP did not display these peaks. The ENP-produced tortillas had higher resistant starch contents and comparable firmness and rollability to those from the TNP but lower quality parameter values. A comparison of the products’ physicochemical properties obtained by the two processes shows the importance of controlling the damage to starch during the milling and extrusion processes to obtain tortillas of better quality. For the first time, we propose the measurement of the viscoelastic parameters G′ and G″ in temperature sweep mode to monitor changes in the degree of starch damage.

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