Liutex and Third Generation of Vortex Identification

2021 ◽  
Author(s):  
Yifei Yu ◽  
Charles Nottage ◽  
Oscar Alvarez ◽  
Chaoqun Liu
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Rotation Axis ◽  
Third Generation ◽  
Vortex Identification ◽  
Identification Methods ◽  
Two Generations ◽  
Definition Of ◽  
Rotation Strength ◽  
Better Than

Abstract Scientists developed many vortex identification methods and Liu classified the traditional vortex identification methods into two generations. Vorticity and vorticity-based methods belong to the first generation while eigenvalues-based methods are considered as the second generation, such as Q criterion and λci method. However, although these methods are widely used, there is still room for improvements. People used to consider direction of vorticity is the swirling axis and the magnitude of it is the rotation strength, but the predictions by vorticity does not match the experiment very well which drove scientists to develop the second-generation methods. All the second-generation methods are scalar-valued and as a result they are unable to locate the swirling. Another problem is even though second-generation methods can predict vortex better than vorticity, they are more or less contaminated by shear. To solve these problems, Liu innovated Liutex recently. Liutex is a vector quantity whose direction represents rotation axis and whose magnitude represents rotation strength. Firstly, the physical essence of rotation axis is provided coming with the mathematical definition of swirling axis which is the direction of Liutex. Secondly, orthogonal transformations are used to find out the rigid rotation speed and that speed is defined as the strength of Liutex. Wang later proposed an explicit formula to calculate Liutex strength without doing orthogonal transformations which makes it much easier to apply Liutex method. Some theories dependent on Liutex concept have been proposed these years. Liutex core lines represent the core of vortex which can uniquely and clearly show vortex structure. Principal coordinate is a special coordinate in which it is easy to decompose the velocity gradient tensor into rotation, shear and stretching parts correctly. And principal decomposition is the decomposition in principal coordinate. The Liutex theory system is gradually formed and they are considered as the third generation by Liu.

‘The problem of validity in field studies of psychological disorders’revisited

1990 ◽  
Vol 20 (1) ◽  
pp. 195-208 ◽  
Author(s):  
Bruce P. Dohrenwend
Keyword(s):  
World War Ii ◽  
First Generation ◽  
Second Generation ◽  
Field Studies ◽  
Epidemiological Studies ◽  
Third Generation ◽  
World War ◽  
Case Identification ◽  
Two Generations ◽  
First And Second Generation

SYNOPSISSince the turn of the century and up to about 1980, there have been two generations of epidemiological studies of the true prevalence of psychiatric disorders: a pre-World War II first generation and a post-World War II second generation. With the appearance of DSM-III in 1980 and the changes in epidemiological proceducres coincident with it, it has become meaningful in the US to talk about the beginnings of a new, third generation or studies in psychiatric epidemiology. The purposes of this paper are: first, to briefly summarize the problems of validity with the procedures for case identification and diagnosis in the first-and second-generation studies; second, to consider some of the newer developments with regard to diagnostic instruments that either are or should be influencing third-generation studies; third, to discuss some of the problems of validity in the handful of third-generation studies done so far; and fourth, to describe and illustrate an approach that seems to make sense in the context of gaps in knowledge of aetiology and pathogenesis that leave us still dependent on interviews for case identification and classification.

scholarly journals Effect of food on growth and fecundity Brine Shrimp Artemia spp. laboratory Conditions

2009 ◽  
Vol 6 (3) ◽  
pp. 448-454
Author(s):  
Baghdad Science Journal
Keyword(s):  
Fresh Water ◽  
First Generation ◽  
Second Generation ◽  
Average Length ◽  
Two Generations ◽  
Effect Of Food ◽  
Brood Number ◽  
The Individual ◽  
First And Second Generation ◽  
Better Than

This in order to test the effect of food on growth and fecundity, two kinds of food have been used the algae Scendesmus quadricaudae and fresh water shrimp powder. For two generations, growth and productivity have been followed up. The fresh water shrimp has been noticed as a food better than algae, because it caused recording, for the two generation higher length rate for the weeks of experiment. The individuals length rate at the end of the forth week reached 9.35 and 9.48 mm for the first generation and second generation respectively. The average length weekly increase rate for the first and second generations individuals feeding on dried shrimp was higher through the first and second week compared to what was recorded when feeding algae. The results showed that the fecundity of the individuals feeding on dried better than those feeding on algae. These individuals got matured in about 15 – 18 days old for the first generation and about 16 – 18 days old for the second generation s. Broods number for the two generation was four; the resulting generation was as nuplii larvae. The average number of the generation nauplii was 55.53, 61.20, 16.13 and 57.73 nauplii per mother for the four broads respectively. The average number of the second generation was 56.56,58.10,61.73 and 49.96 nauplii per mother for the four broods respectively . The individual feeding on algae S. quadricaudae recorded length rate of 7.32 and 7.43 for the first and second generation at the end of the forth week . the individuals got matured in about 19-21mm days old for the first generation and about 18-20 days old for the second generation . The first brood appeared in about 25 – 27 days old for the first generation, and about 30 – 35 days old for the second generation. The brood number was two for the first generation, the first one as nauplii larvae with a rate 40.26 larvae per mother and the second as cyst with a rate 27.90 cysts per mother. For the second generation individuals, one brood has been appeared from which the resulting generation was as cysts with a rate of 45.66 cysts per mother.

The Brown Mite, Bryobia arborea Morgan and Anderson (Acarina: Tetranychidae), on Apple in Nova Scotia.: I. Influence of Intratree Distribution on the Selection of Sampling Units. II. Differences in Habits and Seasonal Trends in Orchards With Bivoltine and Trivoltine Populations. III. Distribution of Diapause Eggs. IV. Hatching of Diapause Eggs

1965 ◽  
Vol 97 (12) ◽  
pp. 1303-1318 ◽  
Author(s):  
H. J. Herbert
Keyword(s):  
Nova Scotia ◽  
First Generation ◽  
Second Generation ◽  
Central Area ◽  
Third Generation ◽  
Apple Trees ◽  
Seasonal Trends ◽  
Sample Unit ◽  
The Third ◽  
Selection Of

AbstractIn Nova Scotia one leaf cluster with an adjoining 1 inch of twig taken from the inside of each of 10 apple trees replicated four times is an adequate sample unit to measure the density of the brown mite.The brown mite has one generation with a partial second in some orchards and one with a partial second and partial third in others. The first generation adults in the bivoltine and trivoltine populations lay summer eggs on the leaves and twigs, and diapause eggs on tin twigs. The second generation adults in the bivoltine populations lay only diapause eggs; in the trivoltine populations they lay both summer and diapause eggs. The adults of the third generation lay only diapause eggs.The brown mite is found on both the leaves and woody parts of the tree. In orchards with bivoltine populations the proportion of mites on leaves reached a peak of 80% by mid-July, but thereafter gradually decreased to 10% by the end of August. However, in orchards with trivoltine populations the proportion of mites on leaves reached a peak of 80 to 90% by mid-July, remained constant until mid-August, and thereafter decreased to approximately 40% by the end of August.The number of diapause eggs laid by adults of each generation in both the bivoltine and trivoltine populations varies widely. The eggs are deposited on the trunk as well as on the branches, with the heaviest deposition in the central area of the tree. The diapause eggs laid by adults of the first generation are the last to hatch and those laid by the third generation are the first to hatch the following spring.The factors responsible for the differences in the number of generations and in the number of diapause eggs laid are unknown.

scholarly journals Philosophy from the outside in: Rosenzweig’s critical project

2012 ◽  
Vol 23 (2) ◽  
pp. 65-76
Author(s):  
Willi Goetschel
Keyword(s):  
First Generation ◽  
Martin Buber ◽  
Third Generation ◽  
Literary Modernism ◽  
The Third ◽  
Jewish Thought ◽  
Two Generations ◽  
The University ◽  
Critical Intervention ◽  
Hermann Cohen

This paper examines Rosenzweig?s philosophic project in the context of his time as a critical intervention in the discussion of the place of Jewish thought in the university and in society. If Hermann Cohen represented the first generation of Jewish philosophers claiming that participation in the university is constitutive for the institution?s claim to universalism, the second generation-represented by Martin Buber - was more diffident about the university and its openness. For Buber, literary modernism offered what the university would refuse. Disappointed about the failure of the recognition of the efforts of the previous two generations, Rosenzweig represents the third generation. He turns the situation into a creative response anchoring philosophy as a project that calls for a resolute move outside the university.

scholarly journals Toxicity and bioaccumulation of 2,2', 4,4'-tetrabromodiphenyl ether (BDE47) in a laboratory aquatic food chain

2021 ◽  
Author(s):  
Emily Rachel Awad
Keyword(s):  
Polybrominated Diphenyl Ethers ◽  
First Generation ◽  
Second Generation ◽  
Dietary Exposure ◽  
Maternal Exposure ◽  
Water Exposure ◽  
Aquatic Food Chain ◽  
Two Generations ◽  
Survival And Reproduction ◽  
Aquatic Food

Rising levels of polybrominated diphenyl ethers (PBDEs) have been ovserved in the environment, humans, and animlas. Studies have shown that these compounds can elicit toxic effects in animals (e.g. neurotoxicity and thyroid toxicity). This research investigated the effects of BDE47 on the survival and reproduction of Daphnia magna over two generations. The impacts of water-borne exposure were compared to dietary exposure using the following treatments: dosed water (DW), dosed algae (DA) and dosed water and algae (DWA). In the first generation, significant impacts on reproduction were observed in daphnids in the DA and DWA treatments. In the second generation, no significant impacts on reproduction were observed indicating a recovery from maternal exposure. When second generation daphnids were exposed to BDE47, there was high mortality in the DWA treatment anad reduced reproduction in all dosed treatments. Dietary exposure to BDE47 had a more profound impact on daphnid reproduction than water exposure. In the second generation, dietary exposure affected both survival and reproduction and water exposure reduced reproduction, indicating that maternal exposure was a factor.

Distillery Configurations

2019 ◽  
pp. 47-64
Author(s):  
Karl Raitz
Keyword(s):  
Nineteenth Century ◽  
Labor Force ◽  
First Generation ◽  
Second Generation ◽  
High Capacity ◽  
Third Generation ◽  
Early Nineteenth Century ◽  
Railroad Tracks ◽  
Urban Rail ◽  
Capacity Output

Early-nineteenth-century farmers and millers were often craft distillers, mashing and fermenting grain meal in wooden barrels before distilling the liquid in small copper pot stills. Waterwheels powered the first-generation creek-side mills and distilleries. Wood fueled early steam engines; the use of coal required access to better transportation. Second-generation distilleries, operating from the 1830s to the 1880s, used traditional pot stills,although some adopted new column stills, perfected in Scotland, when they began to mechanize. Old still buildings were often modified to accommodate new machinery. Distillers stored whiskey-filled wooden barrels in stack warehouses to age. Industrialization required a larger labor force. By 1880, businesses in Louisville and other river cities were producing steam engines, boilers, and related equipment. Third-generation distilleries operated from the 1880s to 1920; their high-capacity output required more grain and fuel, mandating locations near railroad tracks or navigable rivers. Complementary industries such as cooperages, metal fabricators, slaughterhouses, and tanneries were attracted to urban, rail-side distilleries.

Failure properties of 352 explanted silicone-gel breast implants

1996 ◽  
Vol 4 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Walter Peters ◽  
Dennis Smith ◽  
Stanley Lugowski
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Survival Curve ◽  
Breast Implants ◽  
Thick Wall ◽  
Thin Wall ◽  
Third Generation ◽  
Silicone Gel ◽  
Failure Properties

There have been three generations of silicone-gel breast implants. First generation implants (thick wall – thick gel with Dacron patches) were made from 1963 to 1972. Second generation implants (thin wall-thin gel) were made from 1972 until the mid 1980s. The introduction of third generation implants (stronger wall, low-bleed) was geographically dependent. In Canada, Dow Corning Silastic II implants were introduced in 1986, and Surgitek SCL implants were introduced in 1988. In the present study, a total of 352 silicone-gel breast implants were removed from 239 patients between 1981 and 1995. Their failure properties were dependent upon their generation (year of manufacture) and, for second generation implants, their duration in situ. Of the 352 implants, 20 were first generation, and all were fully intact. Twenty-eight were third generation implants, and 27 were fully intact. Failure properties of the 302 second generation implants were dependent upon their duration of implantation. A survival curve indicated that these implants began to fail (by leaking or rupturing) after four years in situ. By six years, 40% had failed. After 12 years, 95% had failed. Of the 171 second generation implants removed between 1991 and 1995, 77% had failed. The failure properties were similar for the three main manufacturers: Dow Corning, Heyer-Schulte and Surgitek. The failure rate for second generation implants is much higher than was previously believed. This is particularly significant in view of the current difficulty in diagnosing implant failure.

Variation in Australian and Some Overseas Populations of Emex australis and E. spinosa

1979 ◽  
Vol 27 (5) ◽  
pp. 631 ◽  
Author(s):  
PW Weiss ◽  
DM Simmons
Keyword(s):  
South Africa ◽  
Western Australia ◽  
First Generation ◽  
Second Generation ◽  
Emex Australis ◽  
Hierarchical Grouping ◽  
Two Generations

Australian populations of the widespread Emex australis and the more restricted E. spinosa were tested for subspecific variation. The plants were grown for two generations in a glasshouse from seed collected from field populations. The results from growing the first generation showed that two groupings of E. australis could be made on the basis of hierarchical grouping analysis, but the populations were much more similar in the second generation and such groupings could not be made. There were no marked differences between E. australis populations from Australia and South Africa, although one from Hawaii was less vigorous than the others. Amongst Australian populations of E. spinosa, one from Western Australia was less vigorous than the others. It was also found that Australian populations of E. spinosa were generally similar to those from Portugal and slightly more vigorous than those from Morocco.

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