scholarly journals Crown formation from a cavitating bubble close to a free surface

2021 ◽  
Vol 926 ◽  
Author(s):  
Youssef Saade ◽  
Maziyar Jalaal ◽  
Andrea Prosperetti ◽  
Detlef Lohse
Keyword(s):  
Free Surface ◽  
Pressure Ratio ◽  
Free Software ◽  
Control Parameters ◽  
Flow Focusing ◽  
The Third ◽  
Toroidal Bubble ◽  
Crown Formation ◽  
Highly Correlated ◽  
Curved Interface

A rapidly growing bubble close to a free surface induces jetting: a central jet protruding outwards and a crown surrounding it at later stages. While the formation mechanism of the central jet is known and documented, that of the crown remains unsettled. We perform axisymmetric simulations of the problem using the free software program BASILISK, where a finite-volume compressible solver has been implemented, which uses a geometric volume-of-fluid (VoF) method for the tracking of the interface. We show that the mechanism of crown formation is a combination of a pressure distortion over the curved interface, inducing flow focusing, and of a flow reversal, caused by the second expansion of the toroidal bubble that drives the crown. The work culminates in a parametric study with the Weber number, the Reynolds number, the pressure ratio and the dimensionless bubble distance to the free surface as control parameters. Their effects on both the central jet and the crown are explored. For high Weber numbers, we observe the formation of weaker ‘secondary crowns’, highly correlated with the third oscillation cycle of the bubble.

scholarly journals Virulence Phenotypes and Molecular Genotypes in Collections of Puccinia triticina from Italy

Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 420-424 ◽  
Author(s):  
Paola Mantovani ◽  
Marco Maccaferri ◽  
Roberto Tuberosa ◽  
James Kolmer
Keyword(s):  
Durum Wheat ◽  
Common Wheat ◽  
Puccinia Triticina ◽  
Leaf Rust Resistance ◽  
Leaf Rust Resistance Gene ◽  
The Third ◽  
Virulence Phenotype ◽  
Ssr Loci ◽  
Highly Correlated ◽  
Simple Sequence

Twenty-four isolates of Puccinia triticina from Italy were characterized for virulence to seedlings of 22 common wheat Thatcher isolines, each with a different leaf rust resistance gene, and for molecular genotypes at 15 simple sequence repeat (SSR) loci. The isolates were compared to a set of 13 previously characterized P. triticina isolates from either durum or common wheat. Clustering based on virulence phenotypes and SSR genotypes grouped the Italian P. triticina isolates into three groups. In the first group, the isolates had virulence phenotypes and SSR genotypes that were similar to the isolates collected from durum wheat. Isolates in the second group were unique because they had virulence similar to the isolates from common wheat but were distinct for SSR genotypes compared to the isolates from durum wheat and from common wheat. Isolates in the third group had virulence phenotypes and SSR genotypes closely related to the isolates from common wheat. The isolates were grouped based on the known or assumed host of origin, virulence phenotype, and SSR genotypes. Measures of FST and RST for SSR genotypes, and ΦST for virulence phenotype were significant, which indicated differentiation among the three groups of isolates. Virulence phenotypes and molecular genotypes were highly correlated with r = 0.74.

A Two-Dimensional Potential Flow Model of the Wave Field Generated by a Semisubmerged Body in Heaving Motion

1988 ◽  
Vol 32 (02) ◽  
pp. 83-91
Author(s):  
X. M. Wang ◽  
M. L. Spaulding
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Potential Flow ◽  
Flow Model ◽  
Second Order ◽  
Two Dimensional ◽  
Third Order ◽  
The Third ◽  
Potential Flow Model ◽  
Good Agreement

A two-dimensional potential flow model is formulated to predict the wave field and forces generated by a sere!submerged body in forced heaving motion. The potential flow problem is solved on a boundary fitted coordinate system that deforms in response to the motion of the free surface and the heaving body. The full nonlinear kinematic and dynamic boundary conditions are used at the free surface. The governing equations and associated boundary conditions are solved by a second-order finite-difference technique based on the modified Euler method for the time domain and a successive overrelaxation (SOR) procedure for the spatial domain. A series of sensitivity studies of grid size and resolution, time step, free surface and body grid redistribution schemes, convergence criteria, and free surface body boundary condition specification was performed to investigate the computational characteristics of the model. The model was applied to predict the forces generated by the forced oscillation of a U-shaped cylinder. Numerical model predictions are generally in good agreement with the available second-order theories for the first-order pressure and force coefficients, but clearly show that the third-order terms are larger than the second-order terms when nonlinearity becomes important in the dimensionless frequency range 1≤ Fr≤ 2. The model results are in good agreement with the available experimental data and confirm the importance of the third order terms.

scholarly journals Serological and shedding patterns after Coxiella burnetii vaccination in the third gestation trimester in dairy cows

2014 ◽  
Vol 62 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Joan Tutusaus ◽  
Fernando López-Gatius ◽  
Beatriz Serrano ◽  
Eva Monleón ◽  
Juan Badiola ◽  
...  
Keyword(s):  
Phase I ◽  
Dairy Cows ◽  
Coxiella Burnetii ◽  
Post Partum ◽  
Antibody Detection ◽  
Vaginal Fluid ◽  
Third Trimester ◽  
The Third ◽  
Kaplan Meier ◽  
Highly Correlated

This study sought to assess the effects of an inactivated phase I vaccine against Coxiella burnetii at the start of the third trimester of gestation on serological profiles, bacterial shedding patterns and subsequent reproductive performance in dairy cows. Cows were randomly assigned to a control (n = 78) or a vaccinated (n = 78) group on days 171–177 of gestation. Samples of placenta and colostrums at parturition, vaginal fluid, faeces, milk (PCR identification) and blood (anti-C. burnetii antibody detection) were obtained on the day of treatment and on days 91–97 post partum, and also on parturition day and weekly on days 1–7, 8–14, 15–21, 22–28 and 29–35 post partum in a subset of 70 animals. By Kaplan-Meier survival analysis, no significant effect of vaccination was detected on any of the reproductive variables studied. According to the odds ratio, C. burnetii shedding on days 171–177 of gestation was highly correlated with seropositivity against C. burnetii (OR = 9.1), while vaccination was not linked to reduced shedding of the bacterium. In shedders compared to others, the likelihood of pregnancy to first AI decreased and increased by factors of 0.26 and 16.1 on days 1–35 and 91–97 post partum, respectively. In conclusion, when administered at the start of the third trimester of pregnancy, the inactivated C. burnetii phase I vaccine failed to reduce bacterial shedding.

Variation in milk cell counts during lactation of British Friesian cattle

1983 ◽  
Vol 36 (3) ◽  
pp. 335-339 ◽  
Author(s):  
P. D. P. Wood ◽  
J. M. Booth
Keyword(s):  
Cell Count ◽  
Clinical Mastitis ◽  
High Cell ◽  
Milk Samples ◽  
The Third ◽  
Cell Counts ◽  
Lactation Curve ◽  
Lactose Concentration ◽  
Highly Correlated ◽  
Friesian Cattle

ABSTRACTA survey was carried out of 1 640 British Friesian heifers calving predominantly in the autumn of 1979. The monthly samples of 1 055 animals showing no reported evidence of udder infection were used to evaluate the parameters of a lactation curve in milk cell count. The model wasC = 190 n−0.4880exp(0·178n)where C is the monthly cell count in millions per 1 during the nth month of lactation. The cell count varied from 230 × 106 in week 1 and 190 × 106 in week 11 to 400 × 106 in week 44 of lactation.On applying the model to the whole sample, milk sampled within a month before or after antibiotic treatment for clinical mastitis contained more than 200 × 106 cells per 1 above the level suggested by the lactation curve. Lactation mean cell counts of treated cows were 400 × 106 cells per 1 higher than those of untreated cows. It was not possible to identify periods in which cows required treatment, or those with high cell counts, by reference to the lactose concentration in the milk samples. Among the untreated cows, the cell count at the third monthly test-day was lower than at any other time, and was more highly correlated with the lactation mean cell count.

People Planning by a Fixed Resource Method

1972 ◽  
Vol 34 (3) ◽  
pp. 799-806 ◽  
Author(s):  
John C. Baird ◽  
Virgil Graf ◽  
Richard Degerman
Keyword(s):  
Cluster Analysis ◽  
Outer Space ◽  
Three Dimensional ◽  
Two Dimensions ◽  
The Third ◽  
Complex Stimuli ◽  
The Mean ◽  
Highly Correlated ◽  
Third Dimension ◽  
The Ideal

Results are presented from a new method to determine a person's conception of complex stimuli. In three related experiments Ss expressed their views of ideal organisms by distributing a fixed resource among hypothetical properties of the ideal. The results from the experiments were highly correlated, lending weight to the reliability and generality of the approach. Cluster analysis and multidimensional scaling were used to group the properties in two dimensions, while the mean amount allocated to a property was represented in the third dimension. A three-dimensional plot was constructed for each of four ideals: the only organism on earth, a member of the only species on earth, an organism going into outer space, and an organism coming to earth from outer space.

Chemical characteristics of traumatic spinal cord edema in cats

1974 ◽  
Vol 40 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Marcial G. Lewin ◽  
Robert R. Hansebout ◽  
Hanna M. Pappius
Keyword(s):  
Spinal Cord ◽  
Functional State ◽  
Structural Integrity ◽  
Dry Weight ◽  
Sodium Concentration ◽  
Post Injury ◽  
Content Type ◽  
The Third ◽  
Tissue Edema ◽  
Highly Correlated

✓ Edema of the spinal cord, secondary to an impact injury produced in cats, was measured chemically. One day after injury a decrease in percentage dry weight and potassium concentration and an increase in sodium concentration were seen in the injured cord. By the second day these changes had spread to adjacent tissue. Edema was maximal between the third and sixth day and had begun to recede by the ninth day. A net loss of potassium, not directly related to the edematous changes, was observed throughout the analyzed cord starting on the third day and persisting on the ninth day after injury, when edema was regressing. Dexamethasone, started 48 hours before or 5 or 24 hours after injury had only minimal effect on edema but prevented loss of potassium from the injured cord. Six days after injury this effect was statistically significant in all three groups of dexamethasone-treated animals. All treated animals showed significantly better functional recovery than the untreated cats. On the sixth post-injury day the functional state of all animals was highly correlated with the potassium content of the spinal cord. Thus, the beneficial effect of dexamethasone may be related to the postulated role of steroid treatment in the maintenance of structural integrity of cellular elements in traumatized tissues. This could result in a better functional state of the injured cord, as well as in the maintenance of the normal content of potassium, the principal intracellular ion.

GENETIC SOURCES OF RESISTANCE TO BLACKBIRD PREDATION IN SUNFLOWER

1986 ◽  
Vol 66 (1) ◽  
pp. 19-23 ◽  
Author(s):  
DAN E. PARFITT ◽  
GREGORY J. FOX
Keyword(s):  
Agelaius Phoeniceus ◽  
Narrow Sense ◽  
Sources Of Resistance ◽  
Bird Predation ◽  
Narrow Sense Heritability ◽  
The Third ◽  
Naturally Occurring ◽  
Xanthocephalus Xanthocephalus ◽  
Sib Families ◽  
Highly Correlated

Fifty-one sunflower (Helianthus annuus L.) inbreds were grown at three environments (locations) in North Dakota. Inbreds at two locations were subjected to naturally occurring bird predation by redwinged blackbirds (Agelaius phoeniceus L.) and yellowheaded blackbirds (Xanthocephalus xanthocephalus Bonaparte). The third sunflower plot was surrounded by a cage into which redwinged blackbirds were introduced. Bird damage was estimated as percent achenes removed from individual sunflower heads. Significant differences among environments were observed (P < 0.01). However, genotype performance among environments was highly correlated (P < 0.01). Half sib progeny from 36 of these inbreds were grown along with their maternal inbred parents to estimate narrow sense heritability (h2NS) of resistance to bird predation. Estimates of h2NS obtained by parent offspring regression and by covariance among half-sib families were h2NS = 0.69 and h2NS = 0.66, respectively. These estimates indicate a 67% level of heritability for resistance to bird predation, and suggest that it should be possible to develop sunflower lines with improved resistance.Key words: Sunflower, bird feeding, redwinged blackbird, yellowheaded blackbird

Contact temperatures in rolling/sliding surfaces

1965 ◽  
Vol 286 (1404) ◽  
pp. 45-61 ◽  
Keyword(s):  
Free Surface ◽  
Heat Source ◽  
Contact Zone ◽  
Asymptotic Expression ◽  
Sliding Contacts ◽  
Frictional Contacts ◽  
Sliding Surfaces ◽  
The Third ◽  
Temperature Discontinuity ◽  
Surface Temperatures

This paper studies three related but separate problems concerning the surface temperatures of frictional contacts. The first part considers the surface temperatures of two rolling/sliding contacts when the condition is imposed that there must be no temperature discontinuity over the contact zone, for a range of surface speeds such that V 1 /V 2 varies between + 1 and — 1. The second part studies the surface temperatures when a rectangular heat source moves over the surfaces at various speeds. As the speeds increase the asymptotic expression for the temperature becomes more accurate. The third section considers the way the surface temperatures build up when ( a ) the contact is repeated, and ( b ) heat is convected from the free surface.

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