Diffusivity, density, viscosity, and refractive index of nickel ammonium sulfate aqueous solutions

1967 ◽  
Vol 12 (4) ◽  
pp. 516-517 ◽  
Author(s):  
John W. Mullin ◽  
M. M. Osman
Keyword(s):  
Refractive Index ◽  
Aqueous Solutions ◽  
Ammonium Sulfate

A simple model for the refractive index of sodium iodide aqueous solutions

2000 ◽  
Vol 28 (3) ◽  
pp. 282-283 ◽  
Author(s):  
T. L. Narrow ◽  
M. Yoda ◽  
S. I. Abdel-Khalik
Keyword(s):  
Refractive Index ◽  
Simple Model ◽  
Aqueous Solutions ◽  
Sodium Iodide

scholarly journals Modification, calibration, and performance of the Ultra-High Sensitivity Aerosol Spectrometer for particle size distribution and volatility measurements during the Atmospheric Tomography Mission (ATom) airborne campaign

2018 ◽  
Vol 11 (1) ◽  
pp. 369-383 ◽  
Author(s):  
Agnieszka Kupc ◽  
Christina Williamson ◽  
Nicholas L. Wagner ◽  
Mathews Richardson ◽  
Charles A. Brock
Keyword(s):  
Refractive Index ◽  
Ammonium Sulfate ◽  
Surface Area ◽  
Particle Number ◽  
High Sensitivity ◽  
Counting Efficiency ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
And Performance ◽  
Counting Statistics

Abstract. Atmospheric aerosol is a key component of the chemistry and climate of the Earth's atmosphere. Accurate measurement of the concentration of atmospheric particles as a function of their size is fundamental to investigations of particle microphysics, optical characteristics, and chemical processes. We describe the modification, calibration, and performance of two commercially available, Ultra-High Sensitivity Aerosol Spectrometers (UHSASs) as used on the NASA DC-8 aircraft during the Atmospheric Tomography Mission (ATom). To avoid sample flow issues related to pressure variations during aircraft altitude changes, we installed a laminar flow meter on each instrument to measure sample flow directly at the inlet as well as flow controllers to maintain constant volumetric sheath flows. In addition, we added a compact thermodenuder operating at 300 ∘C to the inlet line of one of the instruments. With these modifications, the instruments are capable of making accurate (ranging from 7 % for Dp < 0.07 µm to 1 % for Dp > 0.13 µm), precise (< ±1.2 %), and continuous (1 Hz) measurements of size-resolved particle number concentration over the diameter range of 0.063–1.0 µm at ambient pressures of > 1000 to 225 hPa, while simultaneously providing information on particle volatility. We assessed the effect of uncertainty in the refractive index (n) of ambient particles that are sized by the UHSAS assuming the refractive index of ammonium sulfate (n= 1.52). For calibration particles with n between 1.44 and 1.58, the UHSAS diameter varies by +4/−10 % relative to ammonium sulfate. This diameter uncertainty associated with the range of refractive indices (i.e., particle composition) translates to aerosol surface area and volume uncertainties of +8.4/−17.8 and +12.4/−27.5 %, respectively. In addition to sizing uncertainty, low counting statistics can lead to uncertainties of < 20 % for aerosol surface area and < 30 % for volume with 10 s time resolution. The UHSAS reduction in counting efficiency was corrected for concentrations > 1000 cm−3. Examples of thermodenuded and non-thermodenuded aerosol number and volume size distributions as well as propagated uncertainties are shown for several cases encountered during the ATom project. Uncertainties in particle number concentration were limited by counting statistics, especially in the tropical upper troposphere where accumulation-mode concentrations were sometimes < 20 cm−3 (counting rates ∼ 5 Hz) at standard temperature and pressure.

scholarly journals Sizing response of the Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) and Laser Aerosol Spectrometer (LAS) to changes in submicron aerosol composition and refractive index

2021 ◽  
Vol 14 (6) ◽  
pp. 4517-4542
Author(s):  
Richard H. Moore ◽  
Elizabeth B. Wiggins ◽  
Adam T. Ahern ◽  
Stephen Zimmerman ◽  
Lauren Montgomery ◽  
...  
Keyword(s):  
Refractive Index ◽  
Ammonium Sulfate ◽  
High Sensitivity ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Electrical Mobility ◽  
Aerosol Composition ◽  
Submicron Aerosol ◽  
Fullerene Soot ◽  
Good Agreement

Abstract. We evaluate the sensitivity of the size calibrations of two commercially available, high-resolution optical particle sizers to changes in aerosol composition and complex refractive index (RI). The Droplet Measurement Technologies Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) and the TSI, Inc. Laser Aerosol Spectrometer (LAS) are two commonly used instruments for measuring the portion of the aerosol size distribution with diameters larger than nominally 60–90 nm. Both instruments illuminate particles with a laser and relate the single-particle light scattering intensity and count rate measured over a wide range of angles to the size-dependent particle concentration. While the optical block geometry and flow system are similar for each instrument, a significant difference between the two models is the laser wavelength (1054 nm for the UHSAS and 633 nm for the LAS) and intensity (about 100 times higher for the UHSAS), which may affect the way each instrument sizes non-spherical or absorbing aerosols. Here, we challenge the UHSAS and LAS with laboratory-generated, mobility-size-classified aerosols of known chemical composition to quantify changes in the optical size response relative to that of ammonium sulfate (RI of 1.52+0i at 532 nm) and NIST-traceable polystyrene latex spheres (PSLs with RI of 1.59+0i at 589 nm). Aerosol inorganic salt species are chosen to cover the real refractive index range of 1.32 to 1.78, while chosen light-absorbing carbonaceous aerosols include fullerene soot, nigrosine dye, humic acid, and fulvic acid standards. The instrument response is generally in good agreement with the electrical mobility diameter. However, large undersizing deviations are observed for the low-refractive-index fluoride salts and the strongly absorbing nigrosine dye and fullerene soot particles. Polydisperse size distributions for both fresh and aged wildfire smoke aerosols from the recent Fire Influence on Regional to Global Environments Experiment and Air Quality (FIREX-AQ) and the Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) airborne campaigns show good agreement between both optical sizers and contemporaneous electrical mobility sizing and particle time-of-flight mass spectrometric measurements. We assess the instrument uncertainties by interpolating the laboratory response curves using previously reported RIs and size distributions for multiple aerosol type classifications. These results suggest that, while the optical sizers may underperform for strongly absorbing laboratory compounds and fresh tailpipe emissions measurements, sampling aerosols within the atmospherically relevant range of refractive indices are likely to be sized to better than ±10 %–20 % uncertainty over the submicron aerosol size range when using instruments calibrated with ammonium sulfate.

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