Solubility of single chemical compounds from an atmospheric aerosol in pure water

1997 ◽  
Vol 31 (17) ◽  
pp. 2777-2785 ◽  
Author(s):  
P. Hoffmann ◽  
A.N. Dedik ◽  
F. Deutsch ◽  
T. Sinner ◽  
S. Weber ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Pure Water ◽  
Chemical Compounds ◽  
Single Chemical

scholarly journals Investigations on the Influence of Chemical Compounds on Fog Microphysical Parameters

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 225
Author(s):  
Ognyan Ivanov ◽  
Petar Todorov ◽  
Ismail Gultepe
Keyword(s):  
Droplet Size ◽  
Pure Water ◽  
Potassium Dihydrogen Phosphate ◽  
Chemical Compounds ◽  
Water Volume ◽  
Dihydrogen Phosphate ◽  
Aerosol Composition ◽  
Size Spectra ◽  
The Impact ◽  
Generating System

Lab experiments related to artificial fog studies are limited due to instrument sensitivity to small fog and aerosol particles; therefore, the goal of this work is to evaluate aerosol solute effects on fog physical properties in a lab environment. To reach the goal, an automated fog-generating system was designed and that includes controlled chemical compounds dissolved in pure water. In the analysis, the impact of changing the mass concentration of potassium dihydrogen phosphate—KH2PO4, urea-CO(NH2)2, and potassium hexacyanoferrate trihydrate-K3(Fe(CN)6) on fog droplet size spectra is studied, because visibility is directly related to fog droplet spectra and aerosol composition. In the experiment, various microphysical conditions, including fog droplet size and volume concentration, were analyzed as a function of changing aerosol composition/spectra and fixed thermodynamic conditions. The results showed that fog droplet size spectra vary with the addition of chemical impurities to the pure water volume. For example, increasing KH2PO4 concentration compared to distilled water volume resulted in a higher mean particle size, which led to faster droplet settlement, and that resulted in cleaning air more efficiently compared to pure water fog. Overall, both issues and challenges of the experimental fog generating system with respect to water and aerosol solutions resembling CRBN (chemical, radiological, biological, and nuclear agents) characteristics are provided and evaluated.

scholarly journals Masking the Detection of Taste Stimuli in Rats: NaCl and Sucrose

2020 ◽  
Vol 45 (5) ◽  
pp. 359-370 ◽  
Author(s):  
Ginger D Blonde ◽  
Alan C Spector
Keyword(s):  
Target Stimulus ◽  
Neural Circuits ◽  
Chemical Compounds ◽  
Taste Sensitivity ◽  
Gustatory System ◽  
Detection Thresholds ◽  
Fundamental Properties ◽  
Single Chemical ◽  
Operant Task ◽  
Masking Stimulus

Abstract While psychophysical and neurophysiological assessments of taste sensitivity to single chemical compounds have revealed some fundamental properties of gustatory processing, taste stimuli are rarely ingested in isolation. Arguably, the gustatory system was adapted to identify and report the presence of numerous chemicals ingested concurrently. To begin systematically exploring the detectability of a target stimulus in a background in rodents, we used a gustometer to train rats in a 2-response operant task to detect either NaCl (n = 8) or sucrose (n = 8) dissolved in water, and then tested the sensitivity of rats to the trained NaCl stimulus dissolved in a sucrose masker (0.3, 0.6, or 1.0 M, tested consecutively) versus sucrose, or the trained sucrose stimulus dissolved in a NaCl masker (0.04, 0.2, or 0.4 M) versus NaCl. Detection thresholds (EC50 values) were determined for the target stimulus dissolved in each concentration of the masker. Except for 0.04 M NaCl, all masker concentrations tested increased the target stimulus EC50. Target stimulus detectability decreased systematically as masker concentrations increased. The shift in liminal sensitivity for either target was similar when the threshold for the masker was considered. At least for these prototypical stimuli, it appears that the attenuating impact of a masker on the detection of a target stimulus depends on sensitivity to the masking stimulus. Further study will be required to generalize these results and extend them to more complex maskers, and to discern neural circuits involved in the detection of specific taste signals in the context of noisy backgrounds.

FACTORS AFFECTING THE VIABILITY OF AIR-BORNE BACTERIA: II. THE EFFECT OF CHEMICAL ADDITIVES ON THE BEHAVIOR OF AIR-BORNE CELLS

1960 ◽  
Vol 6 (1) ◽  
pp. 71-87 ◽  
Author(s):  
S. J. Webb
Keyword(s):  
Secondary Alcohol ◽  
Chemical Compounds ◽  
Pyrimidine Ring ◽  
Hydroxyl Group ◽  
Bacterial Suspension ◽  
Chemical Additives ◽  
Large Measure ◽  
Alcohol Group ◽  
Factors Affecting ◽  
Single Chemical

The effect on air-borne cells of single chemical compounds added to a bacterial suspension prior to atomization has been studied. It has been found that some amino acids, long chain protein degredates, some sugars and polyhydroxycyclohexanes can enhance the survival of air-borne cells. The ability of a compound to preserve viability during periods of desiccation has been found to be connected with the presence of an amino and/or secondary alcohol group. For maximal protection these groups need to be substituted onto a six-membered ring nucleus. The hydroxyl group has been found toxic if present on a benzene ring, but protective on a pyrimidine ring. Inositol was found to afford a large measure of stability to the air-borne cells and its stabilizing ability could be destroyed by urea and guanidine. It is suggested that compounds enhance survival by replacing water molecules in protein structure during desiccation through hydrogen bonding and so preserve the natural structure of the cellular proteins. Peaks in death rates at intermediate relative humidity levels have been found to be due to the presence of the added compounds.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Cytochemical analysis of mast cell granules after poly-dl-lysine action

1978 ◽  
Vol 36 (2) ◽  
pp. 278-279
Author(s):  
R. Courtoy ◽  
L.J. Simar ◽  
J. Christophe
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Chemical Compounds ◽  
Cellular Membrane ◽  
Thin Sections ◽  
Organic Bases ◽  
Ferric Thiocyanate ◽  
Cytochemical Analysis ◽  
Mast Cell Granule ◽  
Amine Liberation

Several chemical compounds induce amine liberation from mast cells but do not necessarily provoque the granule expulsion. For example, poly-dl-lysine induces modifications of the cellular membrane permeability which promotes ion exchange at the level of mast cell granules. Few of them are expulsed but the majority remains in the cytoplasm and appears less dense to the electrons. A cytochemical analysis has been performed to determine the composition of these granules after the polylysine action.We have previously reported that it was possible to demonstrate polyanions on epon thin sections using a cetylpyridinium ferric thiocyanate method. Organic bases are selectively stained with cobalt thiocyanate and the sulfhydryle groups are characterized with a silver methenamine reaction. These techniques permit to reveal the mast cell granule constituents, i.e. heparin, biogenic amines and basic proteins.

Growth of near noble metal Pd and Pt thin film silicides morphology and structure

1984 ◽  
Vol 42 ◽  
pp. 498-499
Author(s):  
E. I. Alessandrini ◽  
M. O. Aboelfotoh
Keyword(s):  
Noble Metals ◽  
Annealing Temperature ◽  
Chemical Compounds ◽  
Barrier Properties ◽  
Solid State Reactions ◽  
Transmission Electron ◽  
Stable Chemical ◽  
Metal Thickness ◽  
Amorphous Si ◽  
Si Films

Considerable interest has been generated in solid state reactions between thin films of near noble metals and silicon. These metals deposited on Si form numerous stable chemical compounds at low temperatures and have found applications as Schottky barrier contacts to silicon in VLSI devices. Since the very first phase that nucleates in contact with Si determines the barrier properties, the purpose of our study was to investigate the silicide formation of the near noble metals, Pd and Pt, at very thin thickness of the metal films on amorphous silicon.Films of Pd and Pt in the thickness range of 0.5nm to 20nm were made by room temperature evaporation on 40nm thick amorphous Si films, which were first deposited on 30nm thick amorphous Si3N4 membranes in a window configuration. The deposition rate was 0.1 to 0.5nm/sec and the pressure during deposition was 3 x 10 -7 Torr. The samples were annealed at temperatures in the range from 200° to 650°C in a furnace with helium purified by hot (950°C) Ti particles. Transmission electron microscopy and diffraction techniques were used to evaluate changes in structure and morphology of the phases formed as a function of metal thickness and annealing temperature.

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