comment on "Chemical characterization of atmospheric ions at the High Altitude Research Station Jungfraujoch (Switzerland)"

2016 ◽  
Author(s):  
Anonymous
Keyword(s):  
High Altitude ◽  
Chemical Characterization ◽  
Research Station

Chemical characterization of rainwater at a high-altitude site “Nainital” in the central Himalayas, India

2016 ◽  
Vol 24 (4) ◽  
pp. 3959-3969 ◽  
Author(s):  
Deewan Singh Bisht ◽  
A.K. Srivastava ◽  
H. Joshi ◽  
K. Ram ◽  
N. Singh ◽  
...  
Keyword(s):  
High Altitude ◽  
Chemical Characterization ◽  
Central Himalayas

scholarly journals Physico-chemical Characterization of Gosainkunda Lake

2013 ◽  
Vol 13 (1) ◽  
pp. 107-114 ◽  
Author(s):  
Rosha Raut ◽  
Subodh Sharma ◽  
Rosha M Bajracharya ◽  
Chhatra Mani Sharma ◽  
Smriti Gurung
Keyword(s):  
High Altitude ◽  
Monsoon Season ◽  
Chemical Characterization ◽  
Small Catchment ◽  
Major Cations ◽  
Physico Chemical ◽  
Bedrock Weathering ◽  
Post Monsoon Season ◽  
Cation Type

High altitude lakes are very sensitive to climate change due to their small catchment area, limited vegetation cover, surface water with low nutrients, and thin soil and low bedrock weathering rates. The present study was focused on high altitude Himalayan Lake Gosainkunda, situated at an elevation of 4300 m in the Langtang National Park, and carried out during the post- monsoon season (October) in 2010. The main aim of the study was to assess the water quality quantitatively considering the anthropogenic as well as natural impacts in the lake. The water samples were collected at six different sites to represent entirely the quality of the lake. The sampling sites were systematically designated as the inlet, outlet, human influence site, littoral zone, middle (central) and the deepest part of the lake. Some major cations (Ca++, Mg++, Na+ & K+) and anions (Cl-, SO4 — & HCO3 -) were analyzed; the cation type is dominated by Ca++ (64%) while the anions are dominated by Cl- (49%). Among the trace elements (Al, Fe, Mn, Zn, Cu, Cd, Cr, Ni, Pb & As), except for Al and Fe, all others were found below the detection limit. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 107-114 DOI: http://dx.doi.org/10.3126/njst.v13i1.7449

scholarly journals Characterization and first results of an ice nucleating particle measurement system based on counterflow virtual impactor technique

2014 ◽  
Vol 7 (10) ◽  
pp. 10585-10617 ◽  
Author(s):  
L. P. Schenk ◽  
S. Mertes ◽  
U. Kästner ◽  
F. Frank ◽  
B. Nillius ◽  
...  
Keyword(s):  
Field Experiments ◽  
Water Saturation ◽  
Chemical Characterization ◽  
Number Concentration ◽  
Research Station ◽  
Virtual Impactor ◽  
First Results ◽  
Aerosol Instrumentation ◽  
Set Up

Abstract. A specific instrument combination was developed to achieve a better microphysical and chemical characterization of atmospheric aerosol particles that have the potential to act as ice nucleating particles (INP). For this purpose a pumped counterflow virtual impactor system called IN-PCVI was set up and characterized to separate ice particles that had been activated on INP in the Fast Ice Nucleus Chamber (FINCH) from interstitial, non-activated particles. This coupled setup consisting of FINCH (ice particle activation and counting), IN-PCVI (INP separation and preparation), and further aerosol instrumentation (INP characterization) had been developed for the application in field experiments. The separated INP were characterized on-line with regard to their total number concentration, number size distribution and chemical composition, especially with the Aircraft-based Laser Ablation Aerosol Mass Spectrometer ALABAMA. Moreover, impactor samples for electron microscopy were taken. Due to the coupling the IN-PCVI had to be operated with different flow settings than known from literature, which required a further characterization of its cut-off-behavior. Taking the changed cut-off-behavior into account, the INP number concentration measured by the IN-PCVI system was in good agreement with the one detected by the FINCH optics for water saturation ratios up to 1.01 (ice saturation ratios between 1.21–1.34 and temperatures between −18 and −26 °C). First field results of INP properties are presented which were gained during the INUIT-JFJ/CLACE 2013 campaign at the high altitude research station Jungfraujoch in the Bernese Alps, Switzerland (3580 m a.s.l.).

scholarly journals Chemical characterization of atmospheric ions at the high altitude research station Jungfraujoch (Switzerland)

2017 ◽  
Vol 17 (4) ◽  
pp. 2613-2629 ◽  
Author(s):  
Carla Frege ◽  
Federico Bianchi ◽  
Ugo Molteni ◽  
Jasmin Tröstl ◽  
Heikki Junninen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
High Altitude ◽  
Methanesulfonic Acid ◽  
Chemical Characterization ◽  
Solar Irradiation ◽  
Back Trajectory ◽  
High Signal ◽  
Research Station ◽  
Negative Spectrum ◽  
Air Masses

Abstract. The ion composition at high altitude (3454 m a.s.l.) was measured with an atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF) during a period of 9 months, from August 2013 to April 2014. The negative mass spectra were dominated by the ions of sulfuric, nitric, malonic, and methanesulfonic acid (MSA) as well as SO5−. The most prominent positive ion peaks were from amines. The other cations were mainly organic compounds clustered with a nitrogen-containing ion, which could be either NH4+ or an aminium. Occasionally the positive spectra were characterized by groups of compounds each differing by a methylene group. In the negative spectrum, sulfuric acid was always observed during clear sky conditions following the diurnal cycle of solar irradiation. On many occasions we also saw a high signal of sulfuric acid during nighttime when clusters up to the tetramer were observed. A plausible reason for these events could be evaporation from particles at low relative humidity. A remarkably strong correlation between the signals of SO5− and CH3SO3− was observed for the full measurement period. The presence of these two ions during both the day and the night suggests a non-photochemical channel of formation which is possibly linked to halogen chemistry. Halogenated species, especially Br− and IO3−, were frequently observed in air masses that originated mainly from the Atlantic Ocean and occasionally from continental areas based on back trajectory analyses. We found I2O5 clustered with an ion, a species that was proposed from laboratory and modeling studies. All halogenated ions exhibited an unexpected diurnal behavior with low values during daytime. New particle formation (NPF) events were observed and characterized by (1) highly oxygenated molecules (HOMs) and low sulfuric acid or (2) ammonia–sulfuric acid clusters. We present characteristic spectra for each of these two event types based on 26 nucleation episodes. The mass spectrum of the ammonia–sulfuric acid nucleation event compares very well with laboratory measurements reported from the CLOUD chamber. A source receptor analysis indicates that NPF events at the Jungfraujoch take place within a restricted period of time of 24–48 h after air masses have had contact with the boundary layer. This time frame appears to be crucial to reach an optimal oxidation state and concentration of organic molecules necessary to facilitate nucleation.

Olfactory and Chemical Characterization of Indoor Air-Towards a Psychophysical Model for Air Quality

1981 ◽  
Author(s):  
Birgitta Berglund ◽  
Ulf Berglund ◽  
Thomas Lindvall ◽  
Helene Nicander-Bredberg
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Chemical Characterization

PURIFICATION AND PARTIAL CHEMICAL CHARACTERIZATION OF SHEEP NEUROPHYSIN

1973 ◽  
Vol 74 (2) ◽  
pp. 226-236 ◽  
Author(s):  
Michel Chrétien ◽  
Claude Gilardeau
Keyword(s):  
Amino Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Chemical Characterization ◽  
Terminal Amino Acid ◽  
Amino Acid Determination ◽  
Pituitary Glands ◽  
Terminal Amino ◽  
Partial Chemical ◽  
Acid Determination

ABSTRACT A protein isolated from ovine pituitary glands has been purified, and its homogeneity assessed by NH2- and COOH-terminal amino acid determination, ultracentrifugation studies, and polyacrylamide gel electrophoresis after carboxymethylation. Its chemical and immunochemical properties are closely similar to those of beef and pork neurophysins, less similar to those of human neurophysins. It contains no tryptophan (like other neurophysins) or histidine (like all except bovine neurophysin-I and human neurophysins). It has alanine at the NH2-terminus and valine at the COOH-terminus. Its amino acid composition is similar to, but not identical with those of porcine and bovine neurophysins.

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