We have measured the viscosity of four binary mixtures near their consolute points: (1) methanol+cyclohexane, (2) isobutyric acid+water, (3) nitroethane+3-methylpentane, and (4) 2-butoxyethanol+water. The data are consistent with power-law divergence: η∼‖T−Tc‖−y, an apparent exponent in range 0.0404<y<0.0444. Recent theoretical estimates for y 0.032, which is outside experimental range. value independent whether critical point upper or a lower approach toward Tc at constant...

Table 2 was incorrect due to a sign error of the viscosity ratios CN2(gas) and misinterpretation literature values for helium, nitrogen argon. The corrected table is given in PDF file. For measured value differs from ab initio calculated (19.823 ± 0.006) µPa s by twice combined uncertainty 0.05%.

Commercially manufactured meters that measure the flow of a process gas are often calibrated with known surrogate gas. This requires an accurate model meter and values relevant thermophysical properties for both gases. In particular, calibrating “laminar” near ambient temperature pressure ratio (process viscosity)/(surrogate viscosity) be to approximately 0.1%. With this motivation, we critically reviewed measurements viscosity conducted 18 instruments 25 °C zero density 11 gases: He, Ne,...

We used a novel, overdamped oscillator aboard the Space Shuttle to measure viscosity $\ensuremath{\eta}$ of xenon near its critical density ${\ensuremath{\rho}}_{c}$ and temperature ${T}_{c}.$ In microgravity, useful data were obtained within 0.1 mK ${T}_{c},$ corresponding reduced $t=(T\ensuremath{-}{T}_{c}{)/T}_{c}=3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}.$ Because they avoid detrimental effects gravity at temperatures two decades closer ${T}_{c}$ than best ground...

The viscosities η of carbon dioxide and xenon have been measured near their critical points the exponent y characterizing asymptotic divergence, η∼‖T−Tc‖−y, has determined. Both fluids yielded exponents in range y=0.041±0.001 thus also fell y=0.042±0.002 from our earlier study four binary liquids. This agreement between experiments is first evidence that pure liquids are same dynamic universality class. A recent theoretical value for 0.032. 30% discrepancy much greater than combined errors...

We determined the zero-density viscosity and thermal conductivity of argon with a standard uncertainty 0.084% in temperature range 200 K to 400 K. This is dominated by helium's , which we estimate be 0.080% based upon difference between ab initio experimental values at 298.15 Our results may improve (1) argon–argon interatomic potential, (2) calculated boundary-layer corrections for primary acoustic thermometry, (3) calibrations laminar flow meters as well instruments measuring transport...

We have measured the viscosity of three-component microemulsion water/decane/AOT as a function temperature and droplet volume fraction. At temperatures well below phase-separation is described by treating droplets hard spheres suspended in decane. Upon approaching two-phase region from low temperature, there large (as much factor 4) smooth increase which may be related to percolation-like transition observed electrical conductivity. This not completely consistent with either naive...

We have measured the critical exponent y characterizing divergence of viscosity \ensuremath{\eta}\ensuremath{\propto}\ensuremath{\Vert}T-${\mathit{T}}_{\mathit{c}}$${\mathrm{\ensuremath{\Vert}}}^{\mathrm{\ensuremath{-}}\mathit{y}}$ for carbon dioxide and xenon. The values both fluids fall within range y=0.041\ifmmode\pm\else\textpm\fi{}0.001 are consistent with y=0.042\ifmmode\pm\else\textpm\fi{}0.002 spanned by our earlier data four binary liquid mixtures. This agreement is strongest...

This article describes a model for hydrogen outgassing into stainless steel vacuum chamber. It accounts the geometry of chamber components, dissolved in those and processes diffusion, recombination, trapping. Strongly bound or “trapped” hydrogen, which occurs at heterogeneities such as dislocations grain boundaries, can hold most even though locations comprise fewer than 0.1% all lattice sites. Four simplifications allowed practical use model: (1) Each component was described one-dimensional...

Using a novel, overdamped, oscillator flown aboard the space shuttle, we measured viscosity of xenon near liquid-vapor critical point in frequency range $2\mathrm{Hz}\ensuremath{\le}f\ensuremath{\le}12\mathrm{Hz}$. The divergence is characterized by exponent ${z}_{\ensuremath{\eta}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.0690\ifmmode\pm\else\textpm\fi{}0.0006$, agreement with value...

We used interferometry to measure the density changes associated with late stage of thermal equilibration near liquid-vapor critical point ${\mathrm{SF}}_{6}.$ This experiment was performed on board Space Shuttle in absence considerable obscuring effects gravity. The were analyzed terms exponentially decaying modes predicted by a model for heat diffusion an isothermal container. time constants depended only temperature and not sample's history. In range from ${T}_{c}+98\mathrm{mK}$...

Table 2 was incorrect due to a sign error of the viscosity ratios CN2(gas) and misinterpretation literature values for helium, nitrogen argon. The corrected table is given in PDF file. For measured value differs from ab initio calculated (19.823 ± 0.006) µPa s by twice combined uncertainty 0.05%.

Viscosity ratio measurements made with capillary viscometers exploit the accurate values of viscosity helium calculated ab initio. Accurate argon-to-helium are now used for primary acoustic gas thermometry and most redeterminations Boltzmann constant. enable calibration laminar flow meters surrogate gases their use process gases. We review that comprise one, two, four capillaries. A single is a viscometer when it to measure multiple sequentially, while two- four-capillary instruments...

We report measurements of the viscosity near consolute point triethyl n-hexyl ammonium borate in diphenyl ether. Until recently, this ionic mixture was leading candidate for a “mean-field” fluid composed small molecules. The coexistence curve Singh and Pitzer turbidity Zhang et al. had indicated mean-field static behavior. In contrast, present show critical enhancement similar to that seen Ising fluids. Such an is not expected either or with sufficiently long-ranged forces. were made two...

This article describes an accurate meter for gas flow rates below 1000 μmol/s. (1 μmol/s≅1.3 cm3/min at 0 °C and 1 atm). Two gauges measure the input output pressures as flows through a element consisting of either single quartz capillary or array parallel capillaries. A hydrodynamic model determines molar rate from two pressures, temperature, properties. Measurements with nitrogen demonstrated that three elements could span range 0.1 to μmol/s standard uncertainty less than 0.03%....

Near 25 °C, ab initio calculations of the zero-density viscosity helium gas η He have an uncertainty approximately 0.001%, which is 1/40th best measurements. The uncertainties published for neon and argon are probably much larger. This paper presents new measurements viscosities neon, argon, krypton at °C made with a capillary viscometer that was calibrated helium. resulting ratios Ne/η = 1.59836 ± 0.00037, Ar/η 1.13763 0.00030, Kr/η 1.27520 0.00040. ratio agrees recent, unpublished...