Bubble Nucleation and Growth on Surface of Rapidly Heated Micro Heaters

Time dependent surface temperatures on a micro heater were measured when a voltage pulse of 25~200 μs was applied to the heater. The dimensions of the micro polysilicon heaters fabricated on a silicon substrate are 50×5×0.523 μm3 for a micro line heater and 65×65×0.523 μm3 for a micro square heater. With the minimum voltage needed for bubble growth, the temperature for bubble nucleation on the heater immersed in FC-72 was measured to be 420.7 K for the micro line heater, which is close to the superheat limit of the working fluid. On the other hand a bubble nucleates at temperature of 388 K on the square heater. Bubble nucleation, growth and subsequent collapse process were visualized by a microscope-35 mm camera with a μs flash unit.

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Bubble Growth in Poly(methyl methacrylate) and Carbon Dioxide Mixture

Polymers ◽

10.3390/polym11040648 ◽

2019 ◽

Vol 11 (4) ◽

pp. 648 ◽

Cited By ~ 1

Author(s):

Jie Chu ◽

Xiaofei Xu

Keyword(s):

Methyl Methacrylate ◽

Free Volume ◽

Bubble Growth ◽

Nucleation And Growth ◽

Bubble Nucleation ◽

Physical Reason ◽

Poly Methyl Methacrylate ◽

Start Up ◽

Dynamics Simulations ◽

Small Bubbles

In this paper, we study bubble nucleation and growth in a poly(methyl methacrylate) and CO 2 mixture by molecular dynamics simulations. It is known in the foaming industry that the bubble size has a more uniform distribution with a higher start-up pressure. The real physical reason remains unclear. In this work, we found that the free volume-rich polymer segments could adsorb many small-size bubbles in the region close to the polymer chain. The existence of these small bubbles limits the number of free CO 2 molecules, which is helpful for bubble stabilization. Moreover, the free volume of polymer segments decreases with an increase of the start-up pressure. As a result, the size of the large bubbles becomes more uniform with a higher startup pressure.

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ON THE MECHANISM OF DISSOLUTION OF MAGNESIUM IN AQUEOUS MAGNESIUM CHLORIDE SOLUTIONS: PART II

Canadian Journal of Chemistry ◽

10.1139/v62-074 ◽

1962 ◽

Vol 40 (3) ◽

pp. 463-479 ◽

Cited By ~ 5

Author(s):

E. J. Casey ◽

R. E. Bergeron ◽

G. D. Nagy

Keyword(s):

Magnesium Hydroxide ◽

Bubble Growth ◽

Pressure Range ◽

Solid Material ◽

Bubble Nucleation ◽

The Other ◽

Pressure Measurements ◽

Reaction Products ◽

Rate Of Dissolution ◽

Diffraction Patterns

Measurements have been made of the effect of pressure on the rate of dissolution of Mg at pH 2.0 in two concentrations of aqueous MgCl2. Over the pressure range 0.026–2.5 atmospheres, the rates in 0.3 and 3.0 molal solutions have, respectively, the pressure dependences[Formula: see text]The induction period of the reaction was studied in detail with a sensitive gas-measuring technique. Hydrogen enters the metal in the early stages, to about 1 cc per cc Mg at 27 °C. Its rate of release after the specimen is dried is about five times higher than the rate at which it enters the magnesium.X-Ray diffraction patterns of insoluble reaction products formed on the metal surface after prolonged reaction were examined. Magnesium and magnesium hydroxide are formed in both solutions, while a substantial amount of still unidentified extra solid material (not one of the hydrated hydroxy chlorides) is formed in the 3 molal solution.A mechanism is proposed which describes the pressure measurements quantitatively and is consistent with the other known facts. It involves univalent magnesium as an essential intermediate, the rate being controlled by H2 bubble growth through the gelatinous Mg(OH)2 film, which remains on and protects the surface in 0.3 molal solution, and by bubble nucleation in 3 molal solution, in which the film is complexed away.

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Influence of exposure conditions on helium transport and bubble growth in tungsten

Scientific Reports ◽

10.1038/s41598-021-93542-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Rémi Delaporte-Mathurin ◽

Mykola Ialovega ◽

Etienne A. Hodille ◽

Jonathan Mougenot ◽

Yann Charles ◽

...

Keyword(s):

Bubble Growth ◽

Quantitative Agreement ◽

Nucleation And Growth ◽

Bubble Nucleation ◽

Experimental Measurements ◽

High Flux ◽

The Finite Element Method ◽

Bubble Density ◽

Mean Size ◽

Exposure Conditions

AbstractHelium diffusion, clustering and bubble nucleation and growth is modelled using the finite element method. The existing model from Faney et al. (Model Simul Mater Sci Eng 22:065010, 2018; Nucl Fusion 55:013014, 2015) is implemented with FEniCS and simplified in order to greatly reduce the number of equations. A parametric study is performed to investigate the influence of exposure conditions on helium inventory, bubbles density and size. Temperature is varied from 120 K to 1200 K and the implanted flux of 100 eV He is varied from $$10^{17}\,{\text{m}^{-2}\, \text{s}^{-1}}$$ 10 17 m - 2 s - 1 to $$5 \times 10^{21}\, {\text{m}^{-2}\, \text{s}^{-1}}$$ 5 × 10 21 m - 2 s - 1 . Bubble mean size increases as a power law of time whereas the bubble density reaches a maximum. The maximum He content in bubbles was approximately $$4 \times 10^{8}$$ 4 × 10 8 He at $$5 \times 10^{21}\,{\text{m}^{-2}\, \text{s}^{-1}}$$ 5 × 10 21 m - 2 s - 1 . After 1 h of exposure, the helium inventory varies from $$5 \times 10^{16} \,{\text{m}^{-2}}$$ 5 × 10 16 m - 2 at low flux and high temperature to $$10^{25} \,{\text{m}^{-2}}$$ 10 25 m - 2 at high flux and low temperature. The bubbles inventory varies from $$5 \times 10^{12}$$ 5 × 10 12 bubbles m$$^{-2}$$ - 2 to $$2 \times 10^{19}$$ 2 × 10 19 bubbles m$$^{-2}$$ - 2 . Comparison with experimental measurements is performed. The bubble density simulated by the model is in quantitative agreement with experiments.

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Effects of Ambient Pressure on the Instability of a Liquid Boiling Explosively at the Superheat Limit

Journal of Heat Transfer ◽

10.1115/1.3246940 ◽

1986 ◽

Vol 108 (2) ◽

pp. 418-424 ◽

Cited By ~ 61

Author(s):

D. Frost ◽

B. Sturtevant

Keyword(s):

Atmospheric Pressure ◽

Bubble Growth ◽

Absolute Stability ◽

Pressure Field ◽

Ambient Pressure ◽

Small Temperature ◽

Instability Theory ◽

Two Stages ◽

Single Droplets ◽

Superheat Limit

The effect of ambient pressure on the intrinsic instability of rapid vaporization in single droplets boiling explosively at the limit of superheat has been studied experimentally and theoretically. The instability that distorts the evaporating interface and substantially enhances the mass flux at atmospheric pressure is suppressed at high pressure. The radiated pressure field is two orders of magnitude smaller from stabilized bubbles than from unstable. At intermediate pressures bubble growth occurs in two stages, first stable, then unstable. The Landau–Darrieus instability theory predicts absolute stability at atmospheric pressure for a spherical bubble, whereas the theory for planar interfaces yields results in general agreement with observation. The sensitivity of the instability to temperature suggests that small temperature nonuniformities may be responsible for quantitative departures of the behavior from predictions.

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FRW viscous fluid cosmological model with time-dependent inhomogeneous equation of state

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887818300015 ◽

2017 ◽

Vol 15 (01) ◽

pp. 1830001 ◽

Cited By ~ 2

Author(s):

G. S. Khadekar ◽

Deepti Raut

Keyword(s):

Dark Energy ◽

Equation Of State ◽

Quadratic Form ◽

State Parameter ◽

The Other ◽

Time Dependent ◽

Inhomogeneous Equation ◽

Field Equations ◽

Equation Of State Parameter ◽

Viscous Models

In this paper, we present two viscous models of non-perfect fluid by avoiding the introduction of exotic dark energy. We consider the first model in terms of deceleration parameter [Formula: see text] has a viscosity of the form [Formula: see text] and the other model in quadratic form of [Formula: see text] of the type [Formula: see text]. In this framework we find the solutions of field equations by using inhomogeneous equation of state of form [Formula: see text] with equation of state parameter [Formula: see text] is constant and [Formula: see text].

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Bubble Nucleation on Micro Line Heaters

Journal of Heat Transfer ◽

10.1115/1.1571844 ◽

2003 ◽

Vol 125 (4) ◽

pp. 687-692 ◽

Cited By ~ 19

Author(s):

Jung-Yeop Lee ◽

Hong-Chul Park ◽

Jung-Yeul Jung ◽

Ho-Young Kwak

Keyword(s):

Contact Angle ◽

Free Surface ◽

Cluster Model ◽

Bubble Nucleation ◽

Nucleation Temperature ◽

Molecular Cluster ◽

Resistance Characteristic ◽

Nucleation Process ◽

Superheat Limit ◽

Current Resistance

Nucleation temperatures on micro line heaters were measured precisely by obtaining the I-R (current-resistance) characteristic curves of the heaters. The bubble nucleation temperature on the heater with 3 μm width is higher than the superheat limit, while the temperature on the heater with broader width of 5 μm is considerably less than the superheat limit. The nucleation temperatures were also estimated by using the molecular cluster model for bubble nucleation on the cavity free surface with effect of contact angle. The bubble nucleation process was observed by microscope/35 mm camera unit with a flash light of μs duration.

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THE EMISSION OF IONIZING RADIATION DURING A SPARK DISCHARGE

Canadian Journal of Physics ◽

10.1139/p57-036 ◽

1957 ◽

Vol 35 (3) ◽

pp. 324-331 ◽

Cited By ~ 1

Author(s):

W. A. Prowse ◽

G. R. Bainbridge

Keyword(s):

Ionizing Radiation ◽

High Voltage ◽

Voltage Pulse ◽

High Voltage Pulse ◽

Spark Discharge ◽

The Other ◽

Time Interval ◽

Delay Lines

A high voltage pulse lasting 0.35 microsecond is applied to a pair of delay lines, so that two pulses can be picked up from adjustable points of connection on the lines. One is applied to an irradiating gap and the other to a longer test gap, the gaps being so arranged that only mid-gap irradiation occurs. The sparking probability, P, of the test gap is used to indicate the presence of ionizing radiation. Variations of P with the time interval between the two pulses are recorded. They indicate that ionizing radiation is emitted in repeated short flashes. Photographic observations support this view.

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Correlations of substituent effects on proton and fluorine chemical shifts with inverse ionization potentials

Canadian Journal of Chemistry ◽

10.1139/v67-506 ◽

1967 ◽

Vol 45 (24) ◽

pp. 3143-3151 ◽

Cited By ~ 15

Author(s):

T. Schaefer ◽

F. Hruska ◽

H. M. Hutton

Keyword(s):

Electric Fields ◽

Chemical Shifts ◽

Substituent Effects ◽

Group Iv ◽

The Other ◽

Ionization Potentials ◽

Time Dependent ◽

Practical Application ◽

Methyl Proton ◽

Proton Chemical Shifts

The fluorine and proton chemical shifts in some geminally disubstituted vinylidene fluorides and ethylenes are discussed. For these compounds, at least, there are difficulties with an interpretation based on intramolecular time-dependent electric fields. On the other hand, the shifts correlate with the inverse ionization potentials of the substituents, indicating a paramagnetic effect arising from the second term in Ramsey's expression. It is suggested that the effect operates via the bonds and not across space. Methyl proton shifts in a series of substituted methyl compounds of group IV, V, and VI elements show similar correlations. A practical application of the correlation to spectral analysis problems is given.

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A Model of Bubble Nucleation on a Micro Line Heater

Journal of Heat Transfer ◽

10.1115/1.2825950 ◽

1999 ◽

Vol 121 (1) ◽

pp. 220-225 ◽

Cited By ~ 9

Author(s):

S.-D. Oh ◽

S. S. Seung ◽

H. Y. Kwak

Keyword(s):

Bubble Formation ◽

Three Dimensional ◽

Bubble Nucleation ◽

Heat Diffusion ◽

Nucleation Theory ◽

Molecular Cluster ◽

Heater Surface ◽

Calculation Results ◽

Critical Bubble ◽

Superheat Limit

The bubble nucleation mechanism on a cavity-free micro line heater surface was studied by using the molecular cluster model. A finite difference numerical scheme for the three-dimensional transient conduction equation for the liquid was employed to estimate the superheated volume where homogeneous bubble nucleation could occur due to heat diffusion from the heater to the liquid. Calculation results revealed that bubble formation on the heater is possible when the temperature at the hottest point in the heater is greater than the superheat limit of the liquid by 6°C–12°C, which is in agreement with the experimental results. Also it was found that the classical bubble nucleation theory breaks down near the critical point where the radius of the critical bubble is below 100 nm.

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