scholarly journals The Chemical Composition of Cometary Nuclei

1972 ◽  
Vol 45 ◽  
pp. 265-270
Author(s):  
L. M. Shul'man
Keyword(s):  
Chemical Composition ◽  
Cosmic Rays ◽  
Organic Molecules ◽  
Solid Phase ◽  
Critical Concentration ◽  
Energy Output ◽  
Time Interval ◽  
Nuclear Surface ◽  
Solar Cosmic Rays ◽  
Cometary Nuclei

The probable parent-molecules of radicals such as C3 and N2+ are discussed, and it is concluded that cometary nuclei may contain complicated organic molecules, such as C3H4, CH2N2, and C4H2. It is suggested that these molecules are formed by radiation synthesis in solid phase. In a time interval of order 107 to 109 yr bombardment from cosmic rays would be expected to transform the chemical composition to a depth of 1 m. Solar cosmic rays do not penetrate as far, and as a result the surface layer of the nucleus can be enriched with unsaturated hydrocarbons. After a critical concentration of this explosive material is reached a further burst of solar cosmic rays can initiate an explosion and thus an outburst in the comet's brightness. This mechanism is the only one advanced to date that can explain the synchronism of the energy output over the whole nuclear surface.

Cluster analysis of organic molecules in an alpine ice core: the transition from the pre-industrial to the industrial era

2020 ◽  
Author(s):  
Franziska Bachmeier ◽  
Alexander L. Vogel ◽  
Anja Lauer ◽  
Ling Fang ◽  
Katarzyna Arturi ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Chemical Composition ◽  
Atmospheric Aerosol ◽  
Organic Molecules ◽  
Solid Phase ◽  
Ice Core ◽  
Ice Cores ◽  
Aerosol Concentration ◽  
Swiss Alps ◽  
Organic Carbon Concentration

<p>The effects of atmospheric aerosol particles on the Earth’s radiative balance are a major source of uncertainty in global climate models. A distinction and quantification between natural and anthropogenic atmospheric aerosol concentration and their sources has to be made to reduce this uncertainty. Therefore, the natural pre-industrial aerosol concentration of the atmosphere must be determined. Ice cores are climate archives that enable the reconstruction of past atmospheric composition changes.</p><p>For such a reconstruction, an ice core from the Swiss Alps, which covers the years from 1682-1985, was examined for secondary organic aerosol (SOA) compounds. A non-target analysis (NTA) was used to determine the chemical composition of small organic molecules in the ice. The analytical method of the melted ice samples is based on solid-phase extraction, liquid chromatography and high-resolution mass spectrometry. The result of the NTA showed more than 630 features statistically different from the blank. A hierarchical cluster analysis was performed, in which compounds with a similar trend over time were grouped (clustered) together. The cluster analysis separated the considered features into two main groups. The first cluster showed a good correlation with the dissolved organic carbon concentration (DOC) of non-fossil origin (R = 0.75) while the second main group correlated excellently with the fossil DOC (R = 0.95), attributed based on the radiocarbon content. This leads to the presumption that compounds represented in the first cluster originated from biogenic sources while compounds in the second cluster are anthropogenic emissions or SOA formed by anthropogenically emitted precursors. This hypothesis is supported by the temporal trend of the two groups. The potential biogenic compounds show a relative stable behavior throughout time.  At the beginning of the 20th century a decrease of biogenic SOA is recorded. No compounds from the anthropogenic cluster were detected in pre-industrial times, they increase slowly from 1800 and more and more from 1900. Based on the division into the two main clusters, a detailed graphical evaluation of their chemical composition was performed. We show that the suspected biogenic cluster consists mainly of oxidation products of volatile organic compounds (VOC). The presumed anthropogenic cluster consists mainly of organosulfates, nitrooxy-organosulfate, aromatic compounds and mono- and dinitroaromatics.</p>

The influence of nonthermal particles and radiation on the charge state of heavy ions in solar cosmic rays

2004 ◽  
Vol 48 (9) ◽  
pp. 759-768
Author(s):  
Yu. Yu. Kartavykh ◽  
V. M. Ostryakov ◽  
E. Möbius ◽  
M. A. Popecki
Keyword(s):  
Cosmic Rays ◽  
Charge State ◽  
Heavy Ions ◽  
Solar Cosmic Rays ◽  
Nonthermal Particles

scholarly journals Variation of the Chemical Composition of Waste Cooking Oils upon Bentonite Filtration

Resources ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 108 ◽  
Author(s):  
Alberto Mannu ◽  
Gina Vlahopoulou ◽  
Paolo Urgeghe ◽  
Monica Ferro ◽  
Alessandra Del Caro ◽  
...  
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Solid Phase ◽  
Volatile Fraction ◽  
X Ray Diffraction ◽  
Specific Chemical ◽  
Waste Cooking Oils ◽  
Main Components ◽  
Cooking Oils ◽  
Chemical Groups

The chemical composition and the color of samples of waste cooking oils (WCOs) were determined prior to and after filtration on two different pads of bentonite differing in particle size. The volatile fraction was monitored by headspace solid-phase microextraction (HS-SPME) coupled with gas-chromatography, while the variation of the composition of the main components was analyzed by 1H NMR. Both techniques allowed the detection of some decomposition products, such as polymers, terpenes, and derivatives of the Maillard process. The analysis of the chemical composition prior to and after bentonite treatment revealed a tendency for the clays to retain specific chemical groups (such as carboxylic acids or double bonds), independent of their particle size. A pair comparison test was conducted in order to detect the sensory differences of the intensity of aroma between the WCO treated with the two different bentonites. In addition, characterization of the bentonite by means of powder X-ray diffraction (XRD) and thermogravimetric measurements (TG) was performed.

scholarly journals Propagation of an MHD Shock in the Vicinity of a Magnetic Neutral Sheet

1980 ◽  
Vol 91 ◽  
pp. 323-326
Author(s):  
D. J. Mullan ◽  
R. S. Steinolfson
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Solar Corona ◽  
Large Scale ◽  
Field Structure ◽  
Neutral Sheet ◽  
Solar Cosmic Rays ◽  
Magnetic Field Structure ◽  
Large Scale Magnetic Field ◽  
Highly Correlated

The acceleration of solar cosmic rays in association with certain solar flares is known to be highly correlated with the propagation of an MHD shock through the solar corona (Svestka, 1976). The spatial structure of the sources of solar cosmic rays will be determined by those regions of the corona which are accessible to the flare-induced shock. The regions to which the flare shock is permitted to propagate are determined by the large scale magnetic field structure in the corona. McIntosh (1972, 1979) has demonstrated that quiescent filaments form a single continuous feature (a “baseball stitch”) around the surface of the sun. It is known that helmet streamers overlie quiescent filaments (Pneuman, 1975), and these helmet streamers contain large magnetic neutral sheets which are oriented essentially radially. Hence the magnetic field structure in the low solar corona is characterized by a large-scale radial neutral sheet which weaves around the entire sun following the “baseball stitch”. There is therefore a high probability that as a shock propagates away from a flare, it will eventually encounter this large neutral sheet.

Comparative Study on Compositions of Oil-Water Transition Layer before and after ClO2-Treatment Process

2013 ◽  
Vol 652-654 ◽  
pp. 749-752
Author(s):  
Dan Dan Yuan ◽  
Hong Jun Wu ◽  
Hai Xia Sheng ◽  
Xin Sui ◽  
Bao Hui Wang
Keyword(s):  
Chemical Composition ◽  
Transition Layer ◽  
Solid Phase ◽  
Settling Tank ◽  
Physical Structure ◽  
Solid Particles ◽  
Viscosity Reduction ◽  
Insoluble Residue ◽  
Before And After ◽  
Oil Water

In order to meet the need of separating oil from water in the settling tank of the oilfield, ClO2 treatment for oil-water transition layer in settling tank is introduced. The field test displayed that the technique was achieved by a good performance. For understanding the oxidation and mechanism, compositions of oil-water transition layer were comparatively studied for before/after ClO2-treatment in this paper.The experimental results show that the compositions before and after ClO2-treatment, including physical structure and chemical composition, were varied in the great extension. The physical structure, consisting of water, oil and solid phase, was reduced to less than 5% of water and 0.5% of solid particle and increased to 95% of oil in layer compared with before-treatment, easily leading to clearly separating water from oil. The chemical composition of iron sulfide and acid insoluble substance in solid phase was decreased to more than 90% while the carbonate was reduced more than 70% . After the treatment, the viscosity reduction of the water phase in the layer was reached to 50% after oxidation demulsification with ClO2. The chemistry was discussed based on the principles and experiments. Due to ClO2 destroying (oxidizing) the rigid interface membrane structure which is supported by natural surfactant, polymer and solid particles with interface-active materials, the action accelerates the separating of water and oil and sedimentation of insoluble residue of acid in the layer. By demonstrating the experimental data and discussion, we can effectively control the oxidation performance of chlorine dioxide, which is very meaningful for oilfield on the aspect of stable production of petroleum.

Analysis of Physical Structure and Chemical Composition of Oil-Water Transition Layer in Oil Gathering and Transportation System

2013 ◽  
Vol 652-654 ◽  
pp. 2566-2569
Author(s):  
Dan Dan Yuan ◽  
Hong Jun Wu ◽  
Hai Xia Sheng ◽  
Bao Hui Wang ◽  
Xin Sui
Keyword(s):  
Chemical Composition ◽  
Transition Layer ◽  
Suspended Solids ◽  
Solid Phase ◽  
Freezing Point ◽  
Analytical Data ◽  
Transportation System ◽  
Physical Structure ◽  
Efficient Treatment ◽  
Oil Water

he existence of oil-water transition layer brings a great trouble to the dehydration of oil gathering and transportation system. It leads to raising the electric current of dehydrator and becoming worse of the deoiling and dehydrating properties of the treatment equipment, resulting in the serious influences on oil recovery. For the efficient treatment of the transition layer, it is necessary clearly to understand the structure and composition of the layer. In this paper, the physical structure and chemical composition of the layer were systematically, layer by layer and phase by phase, analyzed by modern instrumental methods The results show that (1）the layer is an emulsion which is composed of oil, water and suspended solids. The water phase has characteristics of weak alkaline，high salinity and viscous polymer. The oil phase contains many natural emulsifiers such as colloid, asphaltene and so on. The solid phase mainly concludes FeS particle which plays a decisive role in suspended solids; (2) the typical transition layer is composed of water and oil which accounts for above 90%, the content of solid impurity, which controls the emulsion of the layer, is less than 10%. Compared with oil phase, the water content of typical transition layer is larger with the density of 0.9~1.0 g/L and high freezing point. The analytical data can be adopted for the treatment of oil-water transition layer and smoothly run operations for oil gathering and transportation.

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