scholarly journals Self-propulsion of inverse Leidenfrost drops on a cryogenic bath

2019 ◽  
Vol 116 (4) ◽  
pp. 1174-1179 ◽  
Author(s):  
Anaïs Gauthier ◽  
Christian Diddens ◽  
Rémi Proville ◽  
Detlef Lohse ◽  
Devaraj van der Meer
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Vapor Film ◽  
Liquid Motion ◽  
Nitrogen Pool ◽  
Slowing Down ◽  
Drop Dynamics ◽  
Leidenfrost Effect ◽  
Hot Bath

When deposited on a hot bath, volatile drops are observed to stay in levitation: the so-called Leidenfrost effect. Here, we discuss drop dynamics in an inverse Leidenfrost situation where room-temperature drops are deposited on a liquid-nitrogen pool and levitate on a vapor film generated by evaporation of the bath. In the seconds following deposition, we observe that the droplets start to glide on the bath along a straight path, only disrupted by elastic bouncing close to the edges of the container. Initially at rest, these self-propelled drops accelerate within a few seconds and reach velocities on the order of a few centimeters per second before slowing down on a longer time scale. They remain self-propelled as long as they are sitting on the bath, even after freezing and cooling down to liquid-nitrogen temperature. We experimentally investigate the parameters that affect liquid motion and propose a model, based on the experimentally and numerically observed (stable) symmetry breaking within the vapor film that supports the drop. When the film thickness and the cooling dynamics of the drops are also modeled, the variations of the drop velocities can be accurately reproduced.

Cryogenic Interlaminar Properties of PBO Fiber/Epoxy Composites

2011 ◽  
Vol 391-392 ◽  
pp. 1445-1449
Author(s):  
Chun Hua Zhang ◽  
Shi Lin Luan ◽  
Xiu Song Qian ◽  
Bao Hua Sun ◽  
Wen Sheng Zhang
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Epoxy Composites ◽  
Bending Test ◽  
Test Results ◽  
Sem Images ◽  
Three Point Bending ◽  
Pbo Fiber ◽  
Interlaminar Shear

The influences of low temperature on the interlaminar properties for PBO fiber/epoxy composites have been studied at liquid nitrogen temperature (77 K) in terms of three point bending test. Results showed that the interlaminar shear strength at 77 K were significantly higher than those at room temperature (RT). For the analysis of the test results, the tensile behaviors of epoxy resin at both room temperature and liquid nitrogen temperature were investigated. The interface between fiber and matrix was observed using SEM images.

Research on DC Breakdown and Flashover Characteristics of PI with Different Temperature

2016 ◽  
Vol 709 ◽  
pp. 11-14
Author(s):  
Tian Ye Niu ◽  
Jia Xin Wu ◽  
Ying Wen Li ◽  
Dong Sheng Xu ◽  
Lu Li ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Rapid Development ◽  
Liquid Nitrogen Temperature ◽  
Power Equipment ◽  
Electrical Characteristics ◽  
Cryogenic Temperatures ◽  
Insulating Materials ◽  
Dielectric Performance ◽  
Working Performance

The electrical characteristics of insulating materials play a key role on the working performance and operation reliability of power equipment. With the rapid development of superconducting technology in recent years,the working temperature of high temperature superconducting power equipment can be controlled around the liquid nitrogen temperature. Due to its excellent dielectric performance and mechanical properties, polyimide have been widely used in power equipment at room temperature. However, polyimide, as a kind of cryogenic insulating materials, is rarely reported at present. Therefore, the study of the insulating characteristics of polyimide at the cryogenic temperatures is of great significance. The DC breakdown property and flashover performance of polyimide are tested around room temperature (300K) and liquid nitrogen temperature (78K). The results show that temperature has some effects on the DC breakdown property and flashover performance of polyimide.

Application of interference fits on cylindrical monochromator crystals to overcome clamping and cooling deformations

2019 ◽  
Vol 26 (2) ◽  
pp. 382-385
Author(s):  
Joshua Stimson ◽  
Michael Ward ◽  
John Sutter ◽  
Sofia Diaz-Moreno ◽  
Simon Alcock ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Silicon Crystal ◽  
Liquid Nitrogen Temperature ◽  
Cryogenic Cooling ◽  
Element Analysis ◽  
Thermal Interface ◽  
Macro Scale ◽  
Order Of Magnitude

In order to provide adequate cryogenic cooling of both existing and next-generation crystal monochromators, a new approach to produce an optimum thermal interface between the first crystal and its copper heat exchanger is proposed. This will ensure that the increased heat load deposited by higher X-ray powers can be properly dissipated. Utilizing a cylindrical silicon crystal, a tubular copper heat exchanger and by exploiting the differing thermal and mechanical properties of the two, a very good thermal interface was achieved at liquid-nitrogen temperatures. The surface flatness of the diffracting plane at one end of the cylindrical crystal was measured at room temperature while unconstrained. The crystal was then placed into the copper heat exchanger, a slide fit at room temperature, and then cooled to liquid-nitrogen temperature. At −200°C the slide fit became an interference fit. This room-temperature `loose' fit was modelled using finite-element analysis to obtain the desired fit at cryogenic temperatures by prescribing the fit at room temperature. Under these conditions, the diffraction surface was measured for distortion due to thermal and mechanical clamping forces. The total deformation was measured to be 30 nm, an order of magnitude improvement over deformation caused by cooling alone with the original side-clamped design this concept method is set to replace. This new methodology also has the advantage that it is repeatable and does not require macro-scale tools to acquire a nanometre-accuracy mounting.

Study of Electrical Properties of Ge-Nanocrystalline Films Deposited by Cluster-Beam Evaporation Technique

1998 ◽  
Vol 536 ◽  
Author(s):  
Souri Banedjee ◽  
H. Ono ◽  
S. Nozaki ◽  
H. Morisaki
Keyword(s):  
Electrical Properties ◽  
Liquid Nitrogen ◽  
Coulomb Blockade ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Cluster Beam ◽  
Nanocrystalline Films ◽  
Current Voltage ◽  
Evaporation Technique

AbstractRoom temperature current-voltage (I-V) characteristics were studied across the thickness of the Ge nanocrystalline films, prepared by the cluster beam evaporation technique. The films thus prepared are deposited either at room temperature (Ge-RT) or at liquid nitrogen temperature (Ge-LNT). Ge-LNT nanofilm is subjected to oxidation while Ge-RT did not get oxidized. Steps were observed in the I-V characteristics of the thin Ge- LNT samples suggesting the Coulomb Blockade effect.

Effect of Rolling Temperature on Microstructure and Mechanical Properties of Cryorolled Al-Mg-Si Alloy Reinforced with 3wt% TiB2 In Situ Composite

2012 ◽  
Vol 584 ◽  
pp. 556-560 ◽  
Author(s):  
B. Gopi ◽  
N. Naga Krishna ◽  
K. Sivaprasad ◽  
K. Venkateswarlu
Keyword(s):  
Mechanical Properties ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
True Strain ◽  
Liquid Nitrogen Temperature ◽  
Tensile Tests ◽  
Rolling Temperature ◽  
Rolled Sample ◽  
Peak Broadening

The present work investigates the effect of rolling temperature on the mechanical properties and microstructural evolution of an Al-Mg-Si alloy with 3wt% TiB2 in-situ composite that was fabricated by stir casting route. The composite was rolled to a true strain of ≈0.7 at three different temperatures viz; room temperature (RT), liquid propanol (LP) and liquid nitrogen (LN) temperatures. Tensile tests revealed that the samples rolled at liquid nitrogen temperature exhibited improved properties compared to the samples rolled at other two temperatures. A tensile strength and ductility of 291 MPa and 8% respectively were exhibited by the liquid nitrogen rolled sample. The strength is observed to be ≈12% higher and ductility is ≈60% more when compared to the room temperature rolled sample. X ray diffraction peaks indicated that rolled samples exhibited considerable increase in peak broadening compared to the unrolled one, which is attributed to the increase of the lattice strain due to distortion and the decrease in grain size of the material. The enhanced mechanical properties of the liquid nitrogen rolled samples were attributed to the combined effect of grain refinement and accumulation of higher dislocation density.

Chemically disordered Ni3Al synthesized by high vacuum evaporation

1991 ◽  
Vol 6 (10) ◽  
pp. 2019-2021 ◽  
Author(s):  
S.R. Harris ◽  
D.H. Pearson ◽  
C.M. Garland ◽  
B. Fultz
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Single Phase ◽  
High Vacuum ◽  
Liquid Nitrogen Temperature ◽  
Vacuum Evaporation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Average Grain Size

Films of chemically disordered fcc Ni3Al were synthesized by the vacuum evaporation of Ni3Al onto room temperature and liquid nitrogen temperature substrates. X-ray diffractometry and transmission electron microscopy showed the material to be single phase with an average grain size of about 4 nm. The formation of the equilibrium L12 ordered phase occurred simultaneously with grain growth at temperatures above 350°C. Differential scanning calorimetry provided ordering enthalpies of 7 kJ/mole and 9 kJ/mole for material evaporated onto room temperature and liquid nitrogen temperature substrates, respectively.

Infrared Spectra of the Alkali Metal Cyanides in the Solid State

1973 ◽  
Vol 27 (2) ◽  
pp. 93-94 ◽  
Author(s):  
Zakya K. Ismail ◽  
Robert H. Hauge ◽  
John L. Margrave
Keyword(s):  
Solid State ◽  
Alkali Metal ◽  
Liquid Nitrogen ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Solid Phase ◽  
Liquid Nitrogen Temperature ◽  
Metal Cyanides ◽  
Sodium And Potassium

The infrared spectra of lithium isocyanide and of sodium and potassium cyanides in the solid phase were examined over the range 4000 to 140 cm−1 at room temperature. A study of the effect of cooling the solids to liquid nitrogen temperature has been carried out.

On The Formation of Si Oxide by Ion Implantation

1985 ◽  
Vol 45 ◽  
Author(s):  
F. Namavar ◽  
J.I. Budnick ◽  
F.H. Sanchez ◽  
H.C. Hayden
Keyword(s):  
Ion Implantation ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Experimental Situation ◽  
Liquid Nitrogen Temperature ◽  
Excess Oxygen ◽  
Implantation Temperature ◽  
Current Densities

ABSTRACTOxygen 0+ ions have been implanted into Si both at room temperature and liquid nitrogen temperature in order to determine the effect of implantation temperature on SiO2 formation. Samples were analysed by RBS with 1.5 MeV He+ ions. The implants of 0+ in Si were done at 150 keV with current densities of ≤10 μA/cm2. For doses of more than 1.5×1018 0+/cm2, in-situ RBS experiments positively indicate a 2:1 oxygen silicon ratio. Increased 0+ doses (for both room temperature and liquid nitrogen temperature) cause the Si02 layers to spread uniformly and symmetrically toward both the surface and the interior. From these results, it is apparent that excess oxygen diffuses toward Si/Si02 interfaces in our experimental situation even at liquid nitrogen temperature.

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