Experimental and Theoretical Study on Mixing Performance in Gas-Stirred Ladles With Throughflow Having Tap-Stream Addition of Particulates

2010 ◽  
Author(s):  
Wen-Jei Yang ◽  
Shuichi Torii
Keyword(s):  
Line Profile ◽  
Theoretical Study ◽  
Gas Bubbles ◽  
Light Sheet ◽  
Injection Rate ◽  
Air Injection ◽  
Two Phase ◽  
Mixing Performance ◽  
Bubble Detachment ◽  
History Of

An experimental study is performed to determine mixing performance in gas-ladles with throughflow having tap-addition of particles. Behavior of ascending gas bubbles in the plume and recirculating liquid-particle two-phase flow is visualized by means of direct photography aided by white light-sheet illumination. The path line profile and the history of ascending velocity of gas bubbles from the gas-injection nozzle installed at the ladle bottom are measured with the aid of the image processing method. It is disclosed that a rhythm is discovered in bubble detachment from the nozzle tip. This rhythm repeats by cycle and is characterized by two distinct patterns, forming the discrete bubbles regime and continuous jet regime for lower and higher air injection rates, respectively. Inspective of air injection rate, the growth of each bubble can be divided into the initial, intermediate, and final stages. Each stage has its own distinct bubble growth velocity, path line profile, and ascending velocity. The theoretical equation is derived to correlate experimental data on bubble path line.

Prediction of flow rates and stability in large scale airlift reactors

1996 ◽  
Vol 34 (5-6) ◽  
pp. 51-57 ◽  
Author(s):  
John W. Hinks ◽  
Howard Cawte ◽  
David A. Sanders ◽  
Adam Hudson ◽  
Christopher N. Dockree
Keyword(s):  
Large Scale ◽  
Injection Rate ◽  
Air Injection ◽  
Stable Operation ◽  
Two Phase ◽  
Nineteen Seventies ◽  
Effluent Quality ◽  
Airlift Reactors ◽  
Injection Rates

Large-scale High Recirculation Airlift Reactors have been used to treat biodegradable waste waters since the mid nineteen seventies. The system is particularly attractive for situations where the land to locate wastewater works is restricted. Little is known, however, about the fluid dynamics of the gas-liquid mixture flowing around the reactor. This makes the determination of air injection rates difficult if effluent quality and dynamic stability are to be maintained. When the air injected is not sufficient to maintain stable operation the reactor contents may reverse violently resulting in down time, failure to achieve target discharge quality and possible damage to the reactor itself. As a result many reactor installations operate at air injection rates above those necessary for the biological processes. The extra air injected results in higher capital and process costs. This paper considers the effect of air injection rates on the hydrodynamic stability of Airlift Reactors and a two-phase model is proposed to predict stable operation at a reduced air injection rate. Results are presented which show the effect of reactor design on stability.

From disturbance to measurement: Application of Coriolis meter for two-phase flow with gas bubbles

2021 ◽  
Vol 79 ◽  
pp. 101892
Author(s):  
Hao Zhu ◽  
Alfred Rieder ◽  
Wolfgang Drahm ◽  
Yaoying Lin ◽  
Andreas Guettler ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Gas Bubbles ◽  
Phase Flow ◽  
Two Phase

The significance of the boundary between the Rhoscolyn and New Harbour formations on Holy Island, North Wales, to the deformation history of Anglesey

2012 ◽  
Vol 150 (3) ◽  
pp. 519-535 ◽  
Author(s):  
JACK E. TREAGUS ◽  
SUSAN H. TREAGUS ◽  
NIGEL H. WOODCOCK
Keyword(s):  
Lower Cambrian ◽  
Depositional Environment ◽  
High Strain ◽  
The Other ◽  
Deformation History ◽  
Two Phase ◽  
Phase Deformation ◽  
North Wales ◽  
History Of ◽  
Tectonic Features

AbstractThe boundary between the Rhoscolyn and New Harbour formations on Holy Island, Anglesey, has been described as a high strain zone or as a thrust. The boundary is here described at four localities, with reference to the contrasting sedimentary and deformational character of the two formations. At one of these localities, Borth Wen, sandstones and conglomerates at the top of the Rhoscolyn Formation are followed, without any break, by tuffs and then mudstones of the New Harbour Formation. It is concluded that there is clear evidence of depositional continuity across the boundary here, and that both formations subsequently shared a common two-phase deformation. The first (D1) was manifestly different in intensity and scale in the two formations, whereas the second (D2) produced very similar structures in both. The other three localities provide continuity of sedimentary and tectonic features at this boundary in a traverse along the length of Holy Island, leading us to identify two previously unrecognized major D1 folds in addition to the Rhoscolyn Anticline. At one of these localities (Holyhead), we confirm the presence of Skolithos just below the boundary, supporting radiometric evidence for a lower Cambrian or later age for the Rhoscolyn Formation. A turbidite interpretation for both the Rhoscolyn and New Harbour formations best fits the available evidence. A deep-water depositional environment is still compatible with the sporadic presence of Skolithos burrows, but less so with reported observations of hummocky and swaley cross-stratification lower down the South Stack Group.

Carboniferous-Triassic gastropod diversity patterns and the Permo-Triassic mass extinction

Paleobiology ◽  
1990 ◽  
Vol 16 (2) ◽  
pp. 187-203 ◽  
Author(s):  
Douglas H. Erwin
Keyword(s):  
Mass Extinction ◽  
Detrended Correspondence Analysis ◽  
Taxonomic Composition ◽  
Late Paleozoic ◽  
Lower Permian ◽  
Two Phase ◽  
Environmental Distribution ◽  
Extinction Rates ◽  
History Of ◽  
Permian Mass Extinction

Paleozoic and post-Paleozoic marine faunas are strikingly different in composition. Paleozoic marine gastropods may be divided into archaic and modern groups based on taxonomic composition, ecological role, and morphology. Paleozoic assemblages were dominated by pleurotomariids (Eotomariidae and Phymatopleuridae), the Pseudozygopleuridae, and, to a lesser extent, the Euomphalidae, while Triassic assemblages were dominated by the Trochiina, Amberleyacea, and new groups of Loxonematoidea and Pleurotomariina. Several new groups of caenogastropods appeared as well. Yet the importance of the end-Permian mass extinction in generating these changes has been questioned. As part of a study of the diversity history of upper Paleozoic and Triassic gastropods, to test the extent to which taxonomic and morphologic trends established in the late Paleozoic are continued after the extinction, and to determine the patterns of selectivity operating during the extinction, I assembled generic and morphologic diversity data for 396 genera in 75 families from the Famennian through the Norian stages. Within this interval, gastropod genera underwent an adaptive radiation during the Visean and Namurian, largely of pleurotomariids, a subsequent period of dynamic stability through the Leonardian, a broad-based decline during the end-Permian mass extinction, and a two-phase post-extinction rebound during the Triassic. The patterns of generic diversity within superfamily-level clades were analyzed using Q-mode factor analysis and detrended correspondence analysis.The results demonstrate that taxonomic affinity, previous clade history, generic age, and gross morphology did not determine survival probability of genera during the end-Permian extinction, with the exception of the bellerophontids, nor did increasing diversity within clades or expansion of particular morphologies prior to the extinction facilitate survival during the extinction or success after it. The pleurotomariids diversified during the Lower Permian, but were heavily hit by the extinction. Similarly, trochiform and turriculate morphologies, among those which Vermeij (1987) has identified as having increased predation resistance, were expanding in the late Paleozoic, but suffered similar extinction rates to other nondiversifying clades. Survival was a consequence of broad geographic and environmental distribution, as was the case during background periods.

scholarly journals Measurements of pitch-off diameter of gas bubbles in liquid metal

2021 ◽  
Vol 2057 (1) ◽  
pp. 012039
Author(s):  
P D Lobanov ◽  
N A Pribaturin ◽  
A I Svetonosov
Keyword(s):  
Liquid Metal ◽  
High Speed ◽  
Electrical Circuit ◽  
Conductivity Method ◽  
Two Phase ◽  
Flow Models ◽  
Bubble Detachment ◽  
Transparent Liquid ◽  
Outflow Channel ◽  
The Rose

Abstract To determine the separation diameter of bubbles in a liquid metal melt, an original technique based on the conductivity method is proposed. A thin electrode is installed in the center of the outflow channel, and the separation of bubbles is determined by closing and opening the electrical circuit. In this way, the separation frequency of the bubbles and their volume can be determined. Additional studies are carried out on a transparent liquid (water). It is shown that the presence of an electrode has little effect on the process of bubble detachment. The processing data of high-speed video filming and the proposed method in a transparent liquid coincide with high accuracy. Measurements of the frequency of bubble detachment in melts of the Rose and lead alloy are carried out. The results obtained are used to tune two-phase flow models when simulating fast neutron reactors with heavy liquid metal coolants.

NEUTRALIZING ANTIBODIES AGAINST MOUSE-ADAPTED LANSING STRAIN OF POLIOMYELITIS VIRUS IN THE SERA OF ACUTE AND CONVALESCENT CASES AND NORMAL INDIVIDUALS

1950 ◽  
Vol 28e (2) ◽  
pp. 34-40
Author(s):  
E. L. Barton ◽  
N. A. Labzoffsky ◽  
W. G. Ross ◽  
L. P. Morrissey
Keyword(s):  
British Columbia ◽  
Neutralizing Antibodies ◽  
Acute Stage ◽  
Present Communication ◽  
Two Phase ◽  
Poliomyelitis Virus ◽  
Normal Individuals ◽  
History Of

The present communication deals with a survey of neutralizing antibodies to mouse-adapted Lansing strain of poliomyelitis virus in the sera of acute, convalescent, and normal individuals during a 1946 epidemic. Two-phase sera were obtained from residents of Ontario and British Columbia and convalescent and normal sera from Quebec. In the sera of 17 out of 35 Ontario patients neutralizing antibodies were demonstrable during the acute stage. In four of these seropositive individuals, there was an increase in the neutralizing titer during convalescence and in three patients there was a notable drop in the titer. The remaining 18 patients were found to be seronegative during both the acute and convalescent stages. Sera from six out of nine British Columbia patients, likewise contained neutralizing antibodies to the Lansing strain of virus during the acute stage. In four of these the titer remained unchanged during convalescence, in one the titer decreased, and another patient became seronegative. Of the remaining three, two continued to be seronegative and one became seropositive during convalescence. Positive neutralization reactions were obtained with 17 out of 44 convalescent sera from Ontario and 62 out of 146 convalescent sera from Quebec Sera from 51 children without history of poliomyelitis and 100 adult sera taken at random from specimens submitted for Wassermann tests were obtained from Quebec. Of the children's sera 43%, and of the adults’, 48%, contained neutralizing antibodies. The results obtained closely agree with those reported by American workers.

Dimensioni e direttrici del mutamento socio-economico in prospettiva territoriale dal 1951 a oggi

2013 ◽  
pp. 78-92
Author(s):  
Domenico Maddaloni ◽  
Fiorenzo Parziale
Keyword(s):  
Principal Component Analysis ◽  
Linear Regression ◽  
Southern Italy ◽  
Principal Component ◽  
Research Strategy ◽  
Two Phase ◽  
Economic Changes ◽  
Local Contexts ◽  
Italian Provinces ◽  
History Of

In this study we go back to examine the economic and sociological changes throughout the local contexts and divisions of our country. The instrument used is a research strategy that combines a two-phase principal component analysis developed by Di Franco and Marradi with multiple linear regression. From data inherent to four key moments in the recent history of Southern Italy and the whole country - 1951, 1971, 1991 and 2007 - we obtain four «photographs» of dimensions that clarify the structure of the selected variables. We then propose two models of path analysis that underline the causal links between the factors emerged from the PCA, in order to reconstruct the socio-economic changes in the Italian provinces from 1951 to 2007.

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