scholarly journals Observation of the Main Natural Parameters Influencing the Formation of Gas Hydrates

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1803
Author(s):  
Alberto Maria Gambelli ◽  
Umberta Tinivella ◽  
Rita Giovannetti ◽  
Beatrice Castellani ◽  
Michela Giustiniani ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Marine Sediments ◽  
Inductively Coupled Plasma ◽  
Hydrate Formation ◽  
Silica Sand ◽  
Small Scale ◽  
Natural Sand ◽  
Inductively Coupled ◽  
Pure Silica ◽  
Plasma Mass Spectrometry

Chemical composition in seawater of marine sediments, as well as the physical properties and chemical composition of soils, influence the phase behavior of natural gas hydrate by disturbing the hydrogen bond network in the water-rich phase before hydrate formation. In this article, some marine sediments samples, collected in National Antarctic Museum in Trieste, were analyzed and properties such as pH, conductivity, salinity, and concentration of main elements of water present in the sediments are reported. The results, obtained by inductively coupled plasma-mass spectrometry (ICP-MS) and ion chromatography (IC) analysis, show that the more abundant cation is sodium and, present in smaller quantities, but not negligible, are calcium, potassium, and magnesium, while the more abundant anion is chloride and sulfate is also appreciable. These results were successively used to determine the thermodynamic parameters and the effect on salinity of water on hydrates’ formation. Then, hydrate formation was experimentally tested using a small-scale apparatus, in the presence of two different porous media: a pure silica sand and a silica-based natural sand, coming from the Mediterranean seafloor. The results proved how the presence of further compounds, rather than silicon, as well as the heterogeneous grainsize and porosity, made this sand a weak thermodynamic and a strong kinetic inhibitor for the hydrate formation process.

Temporal changes of size distribution of mass and relative intensity for ablated particles during laser ablation inductively coupled plasma mass spectrometry

2016 ◽  
Vol 31 (3) ◽  
pp. 809-814 ◽  
Author(s):  
Ryo Machida ◽  
Takashi Nakazawa ◽  
Naoki Furuta
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Chemical Composition ◽  
Size Distribution ◽  
Relative Intensity ◽  
Inductively Coupled Plasma ◽  
Temporal Changes ◽  
Inductively Coupled ◽  
Plasma Mass Spectrometry

Temporal changes of fractionation indexes during laser ablation were investigated by evaluating the size distribution and chemical composition of ablated particles.

Micro-Scale Physical and Chemical Heterogeneities in Biogenic Materials - A Combined Micro-Raman, Chemical Composition and Microhardness Investigation

2004 ◽  
Vol 844 ◽  
Author(s):  
E. Griesshaber ◽  
R. Job ◽  
T. Pettke ◽  
W. W. Schmahl
Keyword(s):  
Chemical Composition ◽  
Inductively Coupled Plasma ◽  
Fibre Composite ◽  
Shell Layer ◽  
Inductively Coupled ◽  
Structural Inhomogeneities ◽  
Secondary Layer ◽  
Plasma Mass Spectrometry ◽  
Microhardness Indentation ◽  
Physical And Chemical

ABSTRACTThe ultrastructure and chemical composition of calcitic shells of the modern brachiopod specimen Magellania flavescens (Linnaeus) – order: Terebratulida – was investigated with μ-Raman spectroscopy, Vickers microhardness indentation and laser-ablation-inductively-coupled-plasma-mass-spectrometry. The shells contain a thin outer, nanocrystalline primary layer, which is followed by an inner, much softer, secondary layer composed of inorganic/organic fibre composite material. We observed significant chemical and structural inhomogeneities within the shells. The calcite A1g Raman mode was slightly reduced from 1084 cm-1 at the hinge (lock) down to 1083.5 cm-1 towards the tip. This is accompanied by a variation of some chemical impurity concentrations (e.g. Mg, Sr). A strong decrease in microhardness and distinct changes in chemical composition from the primary or the outermost part of the secondary layer towards the innermost portion of the secondary shell layer can be observed. Thus, our measurements show that chemical and structural inhomogeneities occur in modern brachiopods and not only between the primary and the secondary shell layer, but also within the secondary layer of the shell.

scholarly journals Variations of tree ring width and chemical composition of wood of pine growing in the area nearby chemical factories

2017 ◽  
Vol 44 (1) ◽  
pp. 226-239 ◽  
Author(s):  
Barbara Sensuła ◽  
Sławomir Wilczyński ◽  
Laurence Monin ◽  
Mohammed Allan ◽  
Anna Pazdur ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Tree Ring ◽  
Inductively Coupled Plasma ◽  
Annual Variation ◽  
Ring Width ◽  
Tree Ring Width ◽  
Inductively Coupled ◽  
Pine Tree ◽  
Plasma Mass Spectrometry ◽  
Trace Element Profiles

Abstract This study reports the variation of tree-ring widths and annual variation of concentration of metals (Na, Mg, Fe, Ni, Cu, Zn, Pb) in pine growing nearby chemical factories. The conifers (Pinus silvestris L.) investigated in this study covered the time span from 1920s to 2010 AD. Tree-ring widths were measured, dated and rechecked using the COFECHA. Radial trace-element profiles were determined by Laser Ablation Inductively Coupled Plasma Mass Spectrometry. The combined usage of tree ring width and chemical composition of wood provides historic records of anthropogenic impact on the environment and allows identifying the behavior adaptation of trees to the pollution. Data of pine tree cores collected from the sites nearby chemical factories show increasing levels of pollution linked to the increasing of industrial activities in Poland and subsequent dust fallout around the site. This study evidences that tree rings can be used as archives of past environmental contamination.

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