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Unimpeded Permeation of Water Through Helium-Leak-Tight ...

REPORTS Unimpeded Permeation of Water Through Helium-Leak–Tight Graphene-Based Membranes R. R. Nair,1,2 H. A. Wu,1,3 P. N. Jayaram,2 I. V. Grigorieva,1 A. K. Geim1,2* Permeation through nanometer pores is important in the design of materials for filtration and separation techniques and because of unusual fundamental behavior arising at the ...

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Comparison of PEEK and VESPEL (R) SP1 characteristics as ...

Comparison of PEEK and VESPEL (R) SP1 characteristics as vacuum seals for fusion applications Article in Vacuum 65(2):137-145 · April 2002 with 731 Reads How we measure 'reads'

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Diffusion Coefficients of n-Alkanes and 1-Alcohols in ...

Polyethylene naphthalate (PEN) is a polyester polymer with well-known good barrier properties. PEN had been used in the food packaging area till 2012 especially as refillable bottles for soft drinks, juices, and beer. Now, PEN is mainly used in technical applications, e.g., for data storage tapes and organic light-emitting diode (OLED) applications. The aim of the study was the determination ...

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Behavior of polymers in high pressure hydrogen ...

Conference: Proposed for presentation at the ASME Pressure Vessels and Piping Conference 2016 held July 17-21, 2016 in Vancouver, BC, Canada ...

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Frontiers | Hydrogen Permeation Through Glass | Materials

Jan 10, 2020· where P 0 is the maximum hydrogen permeation at infinite temperature, also named permeation constant (mol m −1 Pa −1 s −1), E P is the activation energy (J mol −1) for permeation, T is the temperature (K) and R is the gas constant (8.314 J mol −1 K −1). If broader temperature ranges are analyzed, a slight temperature dependence of ...

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FR1000 Test Report - AP Tech

helium permeation testing of AP1510 and AP1410T regulators found that there was a minor outlet presure rise in regulators with PCTFE seats. The data showed that Vespel has a much lower helium permeation rate than PCTFE when tested under the same conditions. In the AP1510 regulators, the helium permeation rate was 5.2 times greater for

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Unimpeded Permeation of Water Through Helium ... - Science

Jan 27, 2012· Permeation through nanometer pores is important in the design of materials for filtration and separation techniques and because of unusual fundamental behavior arising at the molecular scale. We found that submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation …

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Limited Quantum Helium Transportation through Nano ...

Herein, the quantum behavior of helium transportation through one-dimensional nanopores was evaluated by measuring the adsorption of quantum helium in the nanopores of single-walled carbon ...

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PERMEATION OF HELIUM THROUGH POLYMERS AT LOW …

PERMEATION OF HELIUM THROUGH POLYMERS AT LOW TEMPERATURES E. Behrend, U. Schmidtchen, W. Meyer Federal Institute for Materials Research and Testing (BAM), Laboratory 4.44, Unter den Eichen 87, looo Berlin 45, Germany (Fed. Rep.) Polymers are subject to gas diffusion through …

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University of Toyama | Hydrogen Isotope Research Center ...

Hydrogen permeation through vanadium was examined under helium ion irradiation. The upstream surface of a vanadium membrane was exposed to hydrogen gas at 673K and 640 Pa, and the downstream surface was irradiated with 5 keV helium ions. No significant variation in the permeation rate was observed in the initial stage of irradiation.

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The growth of helium bubbles in stainless steel at high ...

The influence of annealing time (1–1000 hours), applied tensile stress (0–130 MPa), temperature (973–1073 K) and helium content (10–300 a.p.p.m.) on the size distribution and density of helium bubbles within the grains of AISI Type 316 stainless steel has been studied by TEM of α …

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H. Börner's research works | Bundesanstalt für ...

Temperature behaviour of permeation of helium through Vespel and Torlon ... in solid materials such as polymers through permeation, ... behaviour of permeation of helium through Vespel and Torlon.

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Helium Diffusion Through Glass - NORTON - 1953 - Journal ...

Using the mass spectrometer as an analytical tool and as a means of rate measurement, the rates of helium diffusion through nine types of glass were measured. The temperature range covered was from –80° to 600°C. The highest rates were for fused silica and …

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Cryogenics | Vol 34, Issue 2, Pages 97-175 (February 1994 ...

select article Dynamics of liquid helium boil-off experiments with a step change in pressure

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XRS Adiabatic Demagnetization Refrigerator (ADR) Cutaway ...

The shell is a cylinder. It is made of Vespel, a polyimide material, which provides high strength with low thermal conductivity. (Vespel is a DuPont trademark.) Not shown in this drawing is a layer of titanium foil on the outside of the Vespel, to block room temperature permeation of helium from the heat switch.

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Leak detection - CERN

at HERA large amounts of Perbunan ® rubber seals with a permeation rate of 2 · 10 2 mbar l mm/s/m 2 are used at the insulating vacuum tank resu lting in a total permeation rate of 2 · 10 5 mbar l/s/m [2]. This long list shows that during design and manufacture great care is necessary to avoid potential leaks. 4 Leak detection methods

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Effect of helium on structure and compression behavior of ...

Apr 12, 2011· Results and Discussion. When a SiO 2 glass is pressurized in helium pressure medium in a diamond anvil cell (DAC), however, we observed unique behavior of both structure and density evolution with pressure. Fig. 1 shows the high-pressure structure factors for SiO 2 glass, measured at the High Pressure Collaborative Access Team (HPCAT) at the Advanced Photon Source (APS).

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Permeation of atmospheric gases through polymer O‐rings ...

Helium permeation through a Viton O‐ring. An initially evacuated flask was filled with helium to 950 hPa. The helium flux was then measured as a function of time (circles). The O‐ring has a thickness of ∼1.7 mm and an exposed surface area of ∼20 mm 2.

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Moisture permeation of environmental seals used in weapons ...

Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees.

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U. Schmidtchen's research works | Bundesanstalt für ...

Temperature behaviour of permeation of helium through Vespel and Torlon. ... Temperature behaviour of permeation of helium through Vespel and …

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Temperature dependence of helium diffusion through …

Helium gas at room temperature is known to diffuse through the epoxies commonly used in various low temperature applications, which can complicate leak detection. The helium flux typically decreases with decreasing temperature. We have measured the flux of helium that passes though thin sections of as-cast clear Stycast 1266, Stycast 2850FT (black)

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Surface behaviour in deuterium permeation through …

For the discussion of permeation behaviour, the crystal structure of the coating before and after the permeation measurements was analysed using x-ray diffraction (XRD). 3. Theory The hydrogen-isotope permeation through a single-layer material can be expressed in principle by a multiplication of twopredominantprocesses:solutionanddiffusion[14 ...

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HELIUM PERMEATION THROUGH TANTALUM METAL. …

The influence of static and dynamic uniaxial tensile stress on the steady-state permeation of helium through multiphase, polycrystalline ceramics and fused silica was investigated. Tests on alumina, mullite, and pure fused silica were conducted at temperatures between 25 and 1000 deg C and at tensile stress levels of 0 to 12000 psi.

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Tritium, deuterium, and helium permeation through EPDM O ...

Additional permeation measurements were made under the following test conditions: deuterium and helium-4 at room temperature and a pressure of 1.0 MPa using the full-scale AL-SX fixture, tritium from 0.1 MPa to 1.0 MPa at 142{degrees}C using the 50.8 mm fixture, and deuterium form room temperature to 150{degrees}C at a pressure of 1.0 MPa using ...

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Temperature behaviour of permeation of helium through ...

Temperature behaviour of permeation of helium through Vespel and Torlon. ... measurements on the solubility and the diffusion constant of helium in two widely used polymers as a function of temperature. A continuous flow cryostat and a helium leak detector were the key elements of the experimental set-up. ... The results show that while the ...

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Effect of helium irradiation on deuterium permeation ...

N2 - In this study, we measured deuterium (D) gas-driven permeation through tungsten (W) foils that had been pre-damaged by helium ions (He+). The goal of this work was to determine how ion-induced damage affects hydrogen isotope permeation.

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Operation of an ADR using helium exchange gas as a ...

for helium to diffuse into the switch, possibly recovering full oper-ation of the ADR. The main difficulty for this option was to bound the helium leak/permeation rate through the shell and assess whether the leakage would occur only near room temperature (characteristic of permeation) or at all temperatures (indicative of a leak).

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Thomas GRADT | Bundesanstalt für Materialforschung und ...

A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text.

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