Controls of Li incorporation in aragonite

2020 ◽  
Author(s):  
Vasileios Mavromatis ◽  
Jean-Michel Brazier ◽  
Katja Goetschl
Keyword(s):  
Growth Rate ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Elemental Ratios ◽  
Mineral Growth ◽  
Chemical Signatures ◽  
Physico Chemical ◽  
Geological Past ◽  
Temperature Proxy ◽  
Li Content

<p>The cation-to-Ca ratio in natural carbonate minerals is routinely used by the geoscientific community in order to reveal information about the conditions occurred during mineral formation in the geological past. Environmental reconstruction, however, relies on our understanding on the mechanisms controlling mineral growth but also on the physico-chemical properties of cations. In this respect experimental studies and laboratory calibrations of elemental ratios in synthetic carbonates provide important insights on the interpretation of the chemical signatures in natural samples. This holds especially truth for the chemical and isotopic signals of carbonates forming in continental environments that are characterized by the absence of bio-induced precipitation, low concentration of solutes in the forming fluid and slow growth rates (e.g. speleothems). In this study, we examine the incorporation of Li in aragonite, owing to its use as a temperature proxy and its importance in paleo-weathering reconstruction. Our preliminary results suggest that aragonite growth rate is likely the most important parameter controlling Li content in the forming phase. This finding comes in excellent agreement with the recent study by Füger et al. (2019). In addition, the experimental work suggest that temperature is also affecting the distribution of Li in aragonite but to a lesser extent than growth rate. It is anticipated that once completed this work will provide the fundamental knowledge needed for adequate interpretation of Li partitioning in aragonite and significantly improve our ability to interpret Li signatures in natural carbonates.</p><p> </p><p>References: Füger et al. 2019. Effect of growth rate and pH on lithium incorporation in calcite, Geochim. Cosmochim. Acta., 248, 14-24.</p>

Parameters controlling the incorporation of Cu in calcite

2020 ◽  
Author(s):  
Jean-Michel Brazier ◽  
Katja Götschl ◽  
Martin Dietzel ◽  
Vasileios Mavromatis
Keyword(s):  
Growth Rate ◽  
Natural Waters ◽  
Fluid Composition ◽  
Partitioning Coefficient ◽  
Mineral Growth ◽  
Chemical Signatures ◽  
Fundamental Understanding ◽  
First Results ◽  
Ph Conditions ◽  
Co Precipitation

<p>Carbonate minerals record, through their chemical and isotopic composition, the environmental conditions occurring at the time of their formation. Thus, the incorporation of traces/impurities in CaCO<sub>3</sub> minerals calcite and aragonite, have been widely studied over the last five decades in order to provide the fundamental knowledge needed for the use of these traces in paleoenvironmental reconstructions. The processes controlling the uptake of traces in natural samples, however, are manifold and hard to distinguish from each other. Thus, experimental co-precipitation studies on synthetic material under strictly controlled abiotic conditions can provide fundamental understanding on the effect of each process involved in the chemical signatures of natural carbonates. In this study, we explore the incorporation of Cu in calcite and its potential as proxy of reactive fluid composition. This transition metal commonly occurs complexed with organic ligands in natural waters, however, it exhibits very high affinity for calcite. Our experiments were performed at pH 6.3 and 8.3, with varying growth rate ranging between 10<sup>-8.5</sup> and 10<sup>-7.6</sup> (mol/m<sup>2</sup>/s). Our first results highlight that the partitioning coefficient of Cu is positively correlated to the calcite growth rate at both pH conditions, indicating an increase of Cu entrapment at higher growth rate. These new preliminary findings could bring fundamental understanding of Cu incorporation in calcite and highlight the potential of Cu partitioning coefficient as a proxy of mineral growth rate.</p>

scholarly journals State-of-the-Art Review of Effervescent-Swirl Atomizers

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2876
Author(s):  
Krystian Czernek ◽  
Michał Hyrycz ◽  
Andżelika Krupińska ◽  
Magdalena Matuszak ◽  
Marek Ochowiak ◽  
...  
Keyword(s):  
Literature Review ◽  
Droplet Diameter ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Injection Pressure ◽  
Spray Angle ◽  
Atomization Process ◽  
Complex Process ◽  
Physico Chemical ◽  
Basic Features

This paper presents issues in the field of theory, construction, calculations, as well as the design of effervescent-swirl atomizers. The results of experimental studies of spraying liquids with different physico-chemical properties for this type of atomizers are discussed. Effervescent-swirl atomization is a complex process and its mechanism is not fully understood. Therefore, the purpose of the manuscript is the complexity of the atomization process and its mechanism as well as the influence of individual parameters on its efficiency were thoroughly analyzed. The analyzed parameters include: atomizer design, outlet shape, gas and liquid flow rate, injection pressure, physicochemical properties of the atomized liquid, pressure drop, outflow coefficient, spray angle, quantitative droplet distributions, and average droplet diameter. Moreover, in the work, on the basis of the literature review, the results of the research related to, inter alia, the phenomenon of air core formation and the influence of a number of parameters on the efficiency of the atomization process are analyzed. The literature review included in the work makes it possible to better understand the atomization process carried out in effervescent-swirl atomizers, and also provides better design criteria and analysis of the efficiency of the tested devices. The article presents correlation equations covering the basic features of the atomization process, which relate a large number of parameters influencing the efficiency of this process and the character of the sprayed liquid, which may be useful in design practice.

scholarly journals Effects of fluoride salt addition to the physico-chemical properties of the MgCl2-NaCl-KCl heat transfer fluid : a molecular dynamics study

2021 ◽  
Author(s):  
Weiguang Zhou ◽  
Yanping Zhang ◽  
Mathieu Salanne
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Experimental Studies ◽  
Chemical Properties ◽  
Heat Transfer Fluid ◽  
Electricity Production ◽  
Fluoride Ions ◽  
Heat Transfer Fluids ◽  
Physico Chemical ◽  
Dynamics Simulations

Concentrated solar plants are promising solutions for electricity production. In these plants, the heat transfer fluid plays an important role, and finding systems with good thermal properties is very important. In this regard, molten salts, and more particularly molten chlorides, are currently investigated. Experimental studies of these melts are difficult and expensive, so complementing them with simulations would allow to test a wider range of compositions. In this work, we show that classical molecular dynamics simulations are suitable for predicting the properties of a ternary salt composed of MgCl2, KCl and NaCl by extensive comparisons with experimental data (and previous simulations) on the density, heat capacity, viscosity and thermal conductivity. We then study the effect of adding fluoride ions in the melt on these properties in order to investigate the suitability of mixed chlorides-fluorides for future heat transfer fluids studies.

scholarly journals VARIOUS FACTORS AFFECT THE QUALITY OF FERMENTED CASSAVA STARCH

2020 ◽  
Vol 20 (2) ◽  
pp. 107-117
Author(s):  
Bambang Triwiyono ◽  
Abdurachman Abdurachman ◽  
Aton Yulianto
Keyword(s):  
Growth Rate ◽  
Starch Granule ◽  
Chemical Properties ◽  
Cassava Starch ◽  
Production Processes ◽  
Expansion Property ◽  
Physico Chemical ◽  
Natural Characteristic ◽  
Fermentative Process

Fermented cassava starch is one of modified cassava starch products and used in many countries in several food products. The fresh extracted cassava starch is modified by a process of fermentation and sun drying by means the traditional methods. Several works have shown that fermentative process alters the starch granule, giving fermented starch its characteristics are different from those of the native cassava starch. The main difference between fermented cassava starch[A1]  and native cassava starch reside in the expansion property. Understanding the transformation of physico-chemical properties of cassava starch during fermentation is important for controlling the production processes. This discourse refers to the several works that intend to chemically show the expansion property of fermented cassava starch, considered a chemically and enzymatically modified product, with acidic characteristics, perforated granules and high expansion capacity.  Expansion is a natural characteristic of fermented cassava starch, defined as the growth rate of the dough during oven cooking, also referred to as expansion rate. The main aim of this discourse is to get a better understanding how to manage the production processes in order to achieve greater consistency in the quality of sour cassava starch. 

scholarly journals 257 Characterization of the Physico-chemical Properties of and Plant Response to Ecologically Sound Organic Substrates in Relation to Rockwool

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 435D-435
Author(s):  
Md. Shahidul Islam ◽  
Tadashi Ito
Keyword(s):  
Growth Rate ◽  
Rice Husk ◽  
Pore Space ◽  
Chemical Properties ◽  
Water Holding Capacity ◽  
Organic Substrates ◽  
Physico Chemical ◽  
Coconut Coir ◽  
Water Holding

Characterization of physico-chemical properties of ecologically sound unprocessed coconut (Cocos nucifera L.) coir and carbonated rice husk in relation to rockwool were investigated to examine the crop performance along with productivity of tomatoes (Lycopersicon esculentum Mill.). In all substrates, the water-filled pore space and water-holding capacity were larger and air-filled pore space was smaller. Bulk densities, water-holding capacity, and water-filled, air-filled, and total pore spaces were lower in carbonated rice husk than coconut coir and rockwool. These values in coconut coir and carbonated rice husk were increased by use. Most of the physical properties, EC, pH, and inorganic elements, of these natural organic substrates were within appropriate levels as growing media. There were little differences in plant height, stem diameter, percent fruit set, harvest index, ascorbic acid, total soluble solid, fruit pH, and leaf chlorophyll ratio. But, number of nodes, internode length, leaf number and area, days to first anthesis, flower number, and fruit number and weight differed significantly among treatments. There was smaller fluctuation in absolute growth rate, relative growth rate, net assimilate rate, and leaf area ratio among the treatments. It appeared that carbonated rice husk and the coconut coir gave better crop performance than rockwool under moderate high temperatures (30 and 35 °C compared to 25 °C). Furthermore, crop productivity from the organic substrate coconut coir and carbonated rice husk gave more profit than that of rockwool. Thus, carbonated rice husk and coconut coir substrates can be used successfully as a bag culture media amendment for producing vegetables, especially in tropical and subtropical areas.

scholarly journals Physico-chemical properties and chromatographic findings of different natural solvent extracts of Vitex negundo Linn.

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Vivek Kumar ◽  
Harmeet Kaur ◽  
Galib R ◽  
Prajapathi P K
Keyword(s):  
Experimental Studies ◽  
Chemical Properties ◽  
Dosage Forms ◽  
Vitex Negundo ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Water As Solvent ◽  
Chemical Profiles

Introduction: Ayurveda, uses various herbs that are converted into different dosage forms mostly in presence of Jala (water) as solvent. In addition to water; seers also advocated certain other solvents for extraction of active principles from the herbs. Works on using traditional solvents other than water in extracting principles from different herbs are not reported till date. Aims: Considering lack of such evidences, an attempt has been made to prepare Nirgundi Ghana (solid extract of Vitex negundo Linn.) in three different solvents i.e. Jala (water), Kanji (sour gruel) and Gomutra (cow’s urine) and analyze respective physico-chemical profiles. Materials and Methods:  Ghana was prepared by classical methods described in Ayurveda. The samples were analyzed through relevant physico-chemical parameters. Results: In pharmaceutical study; yield was found more in presence of Kanji and Gomutra. Physico-chemical profiles showed few differences, but in most of the cases, they were insignificant. Conclusion: Based on preliminary physico-chemical profiles, it cannot be ascertained the usefulness of the finished products in therapeutics. Relevant experimental studies to identify and characterize the active phyto-constituents and evaluate therapeutic utilities of the principles extracted into the respective solvents are essential in further studies. 

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.

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