Maximum Size of a Gas Bubble in the Regime of Automodel Pulsation

2005 ◽  
Vol 31 (4) ◽  
pp. 270 ◽  
Author(s):  
A. O. Maksimov
Keyword(s):  
Maximum Size ◽  
Gas Bubble

The stability of a large gas bubble rising through liquid

1987 ◽  
Vol 184 ◽  
pp. 399-422 ◽  
Author(s):  
G. K. Batchelor
Keyword(s):  
Nonlinear Effects ◽  
Maximum Size ◽  
Vertical Tube ◽  
Radius Of Curvature ◽  
Gas Bubble ◽  
Spherical Cap ◽  
Lack Of Information ◽  
Large Tank ◽  
Bubble Rising ◽  
The Stability

The upper surface of a large gas bubble rising steadily through liquid under gravity is a statically unstable interface, and if the liquid were stationary small sinusoidal disturbances to the interface with wavelength exceeding the critical value Λc determined by surface tension would grow exponentially. The existence of the deforming motion of the liquid adjoining the interface of a steadily rising bubble changes the nature of the problem of stability. It is shown that a small sinusoidal disturbance of the part of the interface that is approximately plane and horizontal remains sinusoidal, although with exponentially increasing wavelength. The amplitude of such a disturbance increases, from the instant at which Λ = Λc until Λ becomes comparable with the radius of curvature of the interface (R), and the largest amplification occurs for a disturbance whose initial wavelength is approximately equal to Λc. With a plausible guess at the disturbance amplitude and wavelength at which bubble break-up due to nonlinear effects is inevitable, it is possible to obtain an approximate numerical relation between the initial magnitude of the disturbance and the maximum value of R for which a bubble remains intact. This relation applies both to a spherical-cap bubble in a large tank and a bubble rising in a vertical tube in which the liquid far ahead of the bubble is stationary. The few published observations of the maximum size of spherical-cap bubbles are not incompatible with the theory, but lack of information about the magnitude of the ambient disturbances in the liquid precludes any close comparison.

Pneumatic Retinopexy

2009 ◽  
Author(s):  
Daniel A. Brinton ◽  
Charles P. Wilkinson
Keyword(s):  
Sulfur Hexafluoride ◽  
Subretinal Fluid ◽  
Maximum Size ◽  
Gas Bubble ◽  
Retinal Break ◽  
Maximum Expansion ◽  
Pneumatic Retinopexy ◽  
Partial Pressures ◽  
The Law ◽  
Surrounding Fluid

Pneumatic retinopexy (PR) is an office-based, sutureless, no-incision alternative to scleral buckling or vitrectomy for the surgical repair of selected retinal detachments. Cryotherapy is applied around the retinal break(s) to form a permanent seal. A gas bubble is injected into the vitreous cavity, and the patient is positioned so that the bubble closes the retinal break(s), allowing resorption of the subretinal fluid (Figure 8–1A–F). As an alternative to cryotherapy, laser photocoagulation can be applied after the intraocular gas has caused the retina to reattach. Sulfur hexafluoride (SF6) is the gas most frequently used with pneumatic retinopexy. Perfluorocarbon gases such as perfluoropropane (C3F8) are sometimes used, and success has also been reported with sterile room air. In selecting a gas, it is important to understand the longevity and expansion characteristics of the gases. SF6 doubles in volume within the eye, reaching its maximum size at about 36 hours. It will generally disappear within about 10–14 days, depending on the amount injected. Perfluoropropane nearly quadruples in volume, reaching maximum size in about three days. The bubble will last 30–45 days in the eye. Room air does not expand, but immediately starts to reabsorb. The air bubble will be gone within just a few days (Table 8–1). The initial expansion of SF6 and C3F8 is due to the law of partial pressures and the solubility coefficients of the gases involved. A 100% SF6 bubble injected into the eye contains no nitrogen or oxygen, but these gases are dissolved in the fluid around the bubble. Due to the law of partial pressures, nitrogen and oxygen will diffuse into the gas bubble. SF6 also starts to diffuse out of the gas bubble into the surrounding fluid which contains no SF6. However, nitrogen and oxygen diffuse across the gas–fluid interface much more quickly than SF6 because of the relative insolubility of SF6. The net result is an initial influx of gas molecules into the bubble, expanding its size until partial pressures equilibrate, net influx equals net egress, and maximum expansion is reached. Then the bubble gradually reabsorbs as the SF6 is slowly dissolved in the surrounding fluid.

Continuous Quantitative Monitoring of Mural, Platelet-Dependent, Thrombus Kinetics in the Crushed Rat Femoral Vein

1991 ◽  
Vol 65 (04) ◽  
pp. 425-431 ◽  
Author(s):  
F Stockmans ◽  
H Deckmyn ◽  
J Gruwez ◽  
J Vermylen ◽  
R Acland
Keyword(s):  
Thrombus Formation ◽  
Femoral Vein ◽  
Maximum Size ◽  
Digital Analysis ◽  
Video Recordings ◽  
Quantitative Monitoring ◽  
Set Up ◽  
Kinetics Of ◽  
Quantitative Nature

SummaryA new in vivo method to study the size and dynamics of a growing mural thrombus was set up in the rat femoral vein. The method uses a standardized crush injury to induce a thrombus, and a newly developed transilluminator combined with digital analysis of video recordings. Thrombi in this model formed rapidly, reaching a maximum size 391 ± 35 sec following injury, after which they degraded with a half-life of 197 ± 31 sec. Histological examination indicated that the thrombi consisted mainly of platelets. The quantitative nature of the transillumination technique was demonstrated by simultaneous measurement of the incorporation of 111In labeled platelets into the thrombus. Thrombus formation, studied at 30 min interval in both femoral veins, showed satisfactory reproducibility overall and within a given animalWith this method we were able to induce a thrombus using a clinically relevant injury and to monitor continuously and reproducibly the kinetics of thrombus formation in a vessel of clinically and surgically relevant size

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

MULTIPLE-SCALE AND NUMERICAL ANALYSES FOR THE NONLINEAR OSCILLATIONS OF A GAS BUBBLE SURROUNDED BY A MAXWELL'S FLUID

2019 ◽  
Vol 46 (3) ◽  
pp. 261-275
Author(s):  
César Yepes ◽  
Jorge Naude ◽  
Federico Mendez ◽  
Margarita Navarrete ◽  
Fátima Moumtadi
Keyword(s):  
Nonlinear Oscillations ◽  
Multiple Scale ◽  
Numerical Analyses ◽  
Gas Bubble

STUDY OF ISOLATED GAS BUBBLE DYNAMICS IN A CENTRIFUGAL ROTOR

2019 ◽  
Author(s):  
Higor Veiga ◽  
Edgar Ofuchi ◽  
Henrique Stel ◽  
Ernesto Mancilla ◽  
Dalton Bertoldi ◽  
...  
Keyword(s):  
Bubble Dynamics ◽  
Gas Bubble

Influx of streaming methane into anoxic waters of the Black Sea basin

2019 ◽  
Vol 59 (6) ◽  
pp. 952-963
Author(s):  
Yu. G. Artemov ◽  
V. N. Egorov ◽  
S. B. Gulin
Keyword(s):  
Spatial Distribution ◽  
Black Sea ◽  
The Black Sea ◽  
Gas Bubble ◽  
Dissolved Methane ◽  
Anoxic Waters ◽  
Deep Waters ◽  
Methane Budget

Based on data on the spatial distribution and fluxes of streaming (bubbling) methane within the Black Sea, the rate of dissolved methane inflow to Black Sea deep waters was assessed. Calculations showed that gas bubble streams annually replenish the methane budget in the Black Sea by 1.2 109 m3, or 0.9 Tg, which is considerably less than determined by known biogeochemical estimates of components of methane balance in the Black Sea.

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