Can agitation determine the polymorphs of calcium carbonate during the decomposition of calcium bicarbonate?

CrystEngComm ◽  
2014 ◽  
Vol 16 (24) ◽  
pp. 5221-5226 ◽  
Author(s):  
Jiuxin Jiang ◽  
Ying Zhang ◽  
Dongdong Xu ◽  
Jianing Liu
Keyword(s):  
Calcium Carbonate ◽  
External Disturbance ◽  
Coulomb Repulsion ◽  
The Other ◽  
Calcium Bicarbonate ◽  
Crystal Spacing

Free of external disturbance, Ca2+ ions stack in the (0001) faces in the mode of (a), corresponding to thermodynamically least stable vaterite phase. To maximally reduce coulomb repulsion under external agitation, one Ca2+ ion moves up and the other moves down for one third of interplanar crystal spacing (b), corresponding to the stable calcite phase.

scholarly journals Nutrient accumulation and biomass production of alfafa after soil amendment with silicates

Revista CERES ◽  
2014 ◽  
Vol 61 (3) ◽  
pp. 406-413 ◽  
Author(s):  
Angélica Cristina Fernandes Deus ◽  
Leonardo Theodoro Bull ◽  
Juliano Corulli Corrêa ◽  
Roberto Lyra Villas Boas
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
Soil Amendment ◽  
Soil Acidity ◽  
Steel Slag ◽  
The Other ◽  
Chemical Characteristics ◽  
Nutrient Accumulation ◽  
Particle Size Fractions ◽  
Soil Liming

Studies on the use of silicate correctives in agriculture show that they have great potential to improve soil chemical characteristics, however, little information is available on the reactivity rates of their particle-size fractions. This study investigated whether the reactivity rates obtained experimentally could be considered in the calculation of ECC (effective calcium carbonate) for soil liming, promoting adequate development of alfalfa plants. Six treatments were evaluated in the experiment, consisting of two slag types applied in two rates. The experimental ECC was used to calculate one of the rates and the ECC determined in the laboratory was used to calculate the other. Rates of limestone and wollastonite were based on the ECC determined in laboratory. The rates of each soil acidity corretive were calculated to increase the base saturation to 80%. The treatments were applied to a Rhodic Hapludox and an Alfisol Ferrudalfs. The methods for ECC determination established for lime can be applied to steel slag. The application of slag corrected soil acidity with consequent accumulation of Ca, P, and Si in alfalfa, favoring DM production.

Percolation in colloidal soils, considered in relation to swelling and cohesiveness

1925 ◽  
Vol 15 (4) ◽  
pp. 434-443 ◽  
Author(s):  
F. Hardy
Keyword(s):  
Calcium Carbonate ◽  
West Indian ◽  
The Other ◽  
Horizontal Flow ◽  
Lateritic Soils ◽  
Lime Content ◽  
Other Hand

(1) The results of experiments on the rate of horizontal flow, and on the rate of gain in mass, or kerosene and of water in fine and crumb fractions of certain West Indian colloidal soils, comprising three siliceous soils containing different amounts of calcium carbonate, and two lateritic soils, are described and tabulated.(2) The methods of experimentation employed were those elaborated by Green and Ampt, whose equations were found, however, not to fit the values obtained, as is to be expected.(3) The siliceous soils examined possess relatively high swelling coefficients, and their component particles, when wetted, cohere to a greater or lesser extent, depending on lime content. These properties appear to account for the relatively low rates of permeability to water in these soils. Lateritic soils, on the other hand, possess low swelling coefficients, and low cohesiveness; water percolates through them relatively very rapidly.

scholarly journals Rice husk ash as corrective of soil acidity

2014 ◽  
Vol 38 (3) ◽  
pp. 934-941 ◽  
Author(s):  
Gláucia Oliveira Islabão ◽  
Ledemar Carlos Vahl ◽  
Luís Carlos Timm ◽  
Donald Luiz Paul ◽  
Aline Hernandez Kath
Keyword(s):  
Calcium Carbonate ◽  
Rice Husk ◽  
Soil Acidity ◽  
Rice Husk Ash ◽  
The Other ◽  
Field Conditions ◽  
Base Saturation ◽  
Absolute Control

Rice husk ash (RHA) is a by-product from the burning of rice husk that can have favorable effects on the soil in terms of acidity correction. The objectives of this study were to determine the effective calcium carbonate equivalent (ECC) of RHA under field conditions, and establish technical criteria as a basis for estimating the overall ECC of RHA. The 12 treatments of the experiment consisted of 10 RHA dosages (0, 10, 20, 30, 40, 60, 80, 100, 120, and 140 Mg ha-1) and two references, one of which was an absolute control (AC) and the other a plot limed and fertilized according to official recommendations (recommended fertilization - RF). The soil was sampled twice (15 and 210 days after incorporating RHA), in the layers 0.00-0.10 and 0.10-0.20 m, to determine the pH(H2O) and base saturation (V%). The ECC and neutralizing value (NV) of RHA were also determined. The results showed that RHA neutralizes soil acidity, in a faster reaction than conventional limestone, despite a low ECC (around 3 %).

USAGE OF CALCIUM CARBONATE BIODEPOSITION IN MODIFICATION OF CEMENTITIOUS COMPOSITES

2018 ◽  
Vol 172 (52) ◽  
pp. 11-22
Author(s):  
Daniel Zawal ◽  
Krzysztof Górski ◽  
Agnieszka Dobosz
Keyword(s):  
Compressive Strength ◽  
Calcium Carbonate ◽  
Construction Materials ◽  
The Other ◽  
Cementitious Composites ◽  
Historic Buildings ◽  
Effective Solution ◽  
Other Hand ◽  
Compressive Strength Of Concrete ◽  
Durability Of Concrete

Biodeterioration of construction materials is an undesired phenomenon, generating high costs of constraction repairs. On the other hand, occurrence of some bacteria can affect prevention and self repair of fractures formed in concrete. Biodeposition is an effective solution for increasing compressive strength of concrete, extending durability of concrete constructions and renovating limestone elements in facades of historic buildings.

PYOCYANINE FORMATION FROM LABELLED SUBSTRATES BY PSEUDOMONAS AERUGINOSA

1957 ◽  
Vol 3 (2) ◽  
pp. 165-169 ◽  
Author(s):  
A. C. Blackwood ◽  
A. C. Neish
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Calcium Carbonate ◽  
Specific Activity ◽  
The Other ◽  
Specific Activities ◽  
Carbonate Salts ◽  
Cell Carbon

Pseudomonas aeruginosa was grown under conditions suitable for pyocyanine production in a medium containing glycerol, L-leucine, DL-alanine, calcium carbonate, salts, and small amounts of various C14-labelled substrates. A comparison of the specific activities of the cell carbon, respiratory carbon dioxide, and pyocyanine carbon showed that glycerol and dihydroxyacetone were the only substrates from which pyocyanine having a specific activity higher than the cell carbon was formed. Glucose, fructose, pyruvate, acetate, and the 13 amino acids tested were inferior in this respect. Alanine, leucine, isoleucine, and glycine were incorporated into pyocyanine more readily than the other amino acids. Phenylalanine and tyrosine, although possessing preformed rings, were poor precursors of pyocyanine and were oxidized more readily than they were assimilated. These results suggest that pyocyanine originates from trioses but gives little indication of the nature of the intermediates.

scholarly journals The Influences of Sintering Process on the Characteristics of Corbiculacea (Etok) Shells Based Hydroxyapatite Powder

2021 ◽  
Vol 2071 (1) ◽  
pp. 012007
Author(s):  
M R M Roslan ◽  
N F M Nasir ◽  
N F Mohammad ◽  
C E Meng ◽  
M S Mohamed ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Crystallite Size ◽  
Calcium Hydroxide ◽  
Lattice Parameters ◽  
The Other ◽  
Chemical Solution ◽  
Sintering Process ◽  
Hydroxyapatite Powder

Abstract Hydroxyapatite (HA) powders were prepared via chemical solution through aqueous solution of calcium hydroxide and phosphoric acid. The calcium precursor was extracted from the calcium carbonate of Corbiculacea shells while the phosphate precursor originated from the commercially available phosphoric acid. The final product of HA powders is then manipulated through the sintering process at 500°C while the other sample was used as it is. XRD result shows significant changes in its crystallinity, crystallite size and lattice parameters after the sintering process. By sintering the HA, the crystallite size and crystallinity were increases as much as 6.25% and 5.31% respectively. SEM on the other hand showed different morphology for both sintering and non-sintering HA powders. For the sintering HA, the grains size is higher which is 5.00μm compared to non-sintering HA which is 3.91μm due to the agglomeration.

scholarly journals Evaluation, Effect of Whitening Agents on Physico-Chemical and Functional Properties of Sardine Surimi (Sardina pilchardus)

2021 ◽  
pp. 74-89
Author(s):  
Imen Zaghbib ◽  
Soumaya Arafa ◽  
Hassouna Mnasser
Keyword(s):  
Hydrogen Peroxide ◽  
Principal Component Analysis ◽  
Calcium Carbonate ◽  
Sodium Bicarbonate ◽  
Functional Properties ◽  
Principal Component ◽  
Textural Properties ◽  
The Other ◽  
Sardina Pilchardus ◽  
Whitening Agent

The effects of hydrogen peroxide (H2O2), sodium bicarbonate (NaHCO3) and calcium carbonate (CaCO3) treatments on the colour and textural properties of sardine surimi (Sardina pilchardus) were studied. Principal Component Analysis (PCA) was applied in order to investigate their effects and to determine the optimum whitening agents used. Addition of CaCO3 and H2O2 significantly improved whiteness of surimi in comparison to NaHCO3 treatments (p < 0.05). Some textural damage and a reduction in WHC values were observed for surimi treated withH2O2 and NaHCO3 (p < 0.05). PCA biplot showed that 1.5% CaCO3 tended to result in improved whiteness, WHC and textural properties since 1.5% CaCO3 sample sits closer to these functional properties vector lines than the other treatments. Whereas, 2.5% H2O2 had positively affected only the whiteness parameter. Results indicated that treating mince with the appropriate type and concentration of whitening agent can improve the functional properties of surimi, particularly from fish species with darker meat such as sardine. Aims: In order to improve whiteness and functional properties of sardine surimi (Sardina pilchardus), the effects of hydrogen peroxide (H2O2), sodium bicarbonate (NaHCO3) and calcium carbonate (CaCO3) treatments were studied. Principal Component Analysis (PCA) was applied in order to investigate their effects and to determine the optimum whitening agents used. Study Design: Experimental Research Design Place and Duration of Study: Research Unit “Biopreservation and Valorisation of Agro-Food Products” of the Higher Graduate School of Food Industry of Tunisia. The study was conducted in 3 months. Methodology: Sardine surimi samples were prepared with different treatments at different concentrations: calcium carbonate (CaCO3), hydrogen peroxide (H2O2) and sodium bicarbonate (NaHCO3). Proximate composition, total pigment, whiteness, water holding capacity and textural properties were investigated. Optimal levels of each whitening agent were determined using PCA. Results: Addition of CaCO3 and H2O2 significantly improved whiteness of surimi in comparison to NaHCO3 treatments (p < 0.05). Some textural damage and a reduction in WHC values were observed for surimi treated withH2O2 and NaHCO3 (p < 0.05). PCA biplot showed that 1.5% CaCO3 tended to result in improved whiteness, WHC and textural properties since 1.5% CaCO3 sample sits closer to these functional properties vector lines than the other treatments. Whereas, 2.5% H2O2 had positively affected only the whiteness parameter. Conclusion: Results indicated that treating mince with the appropriate type and concentration of whitening agent can improve the functional properties of surimi, particularly from fish species with darker meat such as sardine.

scholarly journals Inhibition of scaling water of Tiznit region by "LEVALL®10".

2019 ◽  
Vol 8 (4) ◽  
pp. 283-289 ◽  
Author(s):  
Said Ben-aazza ◽  
Abdallah Hadfi ◽  
M'bark Belattar ◽  
Said Mohareb ◽  
Naima Hafid ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Water Treatment ◽  
Potable Water ◽  
The Other ◽  
Ecological Effect ◽  
Water Pipes ◽  
Other Hand ◽  
The One ◽  
New Generation ◽  
Carbonate Deposits

Combating the formation of calcium carbonate deposits in potable water pipes presents a challenge for water treatment systems, The use of inhibitors is one of the best techniques to prevent or delay the formation of these deposits. It is therefore essential to find a new generation of scale inhibitors, which is distinguished, on the one hand, by a better inhibiting effectiveness of calcium carbonate, and, on the other hand, by their ecological effect due to the respect of health and environment norms.

scholarly journals Results from experiments comparing aqueous and anhydrous ammonia with ‘nitro-chalk’ for grass cut for silage

1973 ◽  
Vol 81 (3) ◽  
pp. 465-480 ◽  
Author(s):  
F. V. Widdowson ◽  
A. Penny ◽  
R. C. Flint
Keyword(s):  
Single Dose ◽  
Calcium Carbonate ◽  
Ammonium Nitrate ◽  
Dry Matter ◽  
Aqueous Ammonia ◽  
The Other ◽  
Anhydrous Ammonia ◽  
N Fertilizers ◽  
Aqueous Urea ◽  
Valid Comparison

SUMMARYIn five experiments made at Rothamsted from 1966 to 1970 ‘Nitro-Chalk’ (ammonium nitrate–calcium carbonate mixture, 21% N) was broadcast for grass cut for silage, either in a single dose in spring or divided equally for three cuts. The ‘Nitro-Chalk’ was used to evaluate anhydrous ammonia (82% N) in 1966, anhydrous ammonia and aqueous ammonia (approximately 26% N) in 1967, 1968 and 1969, and anhydrous ammonia, aqueous ammonia and aqueous urea (18% N) in 1970. All these fertilizers were applied to give 125, 250, 375 and 500 kg N/ha, except in 1968 when 250, 375, 500 and 625 kg N/ha were given.Anhydrous ammonia gave smaller yields (of dry matter) than the other N fertilizers except in 1968, a wet year, when it was at least as good as ‘Nitro-Chalk’, but slightly less good than aqueous ammonia. Yields were larger with autumn- than with springinjected aqueous ammonia and larger with either, than with equivalent single doses of ‘Nitro-Chalk’. Yields with aqueous ammonia were also larger than with ‘Nitro-Chalk’ divided equally for three cuts when more than 375 kg N/ha was tested, but smaller with less. Aqueous urea was as good as a single dose of ‘Nitro-Chalk’ but less good than divided ‘Nitro-Chalk’ in 1970, the only year it was tested. ‘Nitro-Chalk’ divided equally for three cuts gave larger yields than when a single dose of up to 375 kg N/ha was given, but with more N than this a single dose was better.Apparent recovery of N was least from anhydrous ammonia and differed little between autumn and spring injection in 1968, the only year when a valid comparison was possible. Apparent recoveries of N from autumn and from spring-injected aqueous ammonia and from ‘Nitro-Chalk’ broadcast in a single dose differed little, nor did the proportion of the N recovered at each cut. Recovery from ‘Nitro-Chalk’ broadcast in three equal amounts was more uniform, but little larger.Judged by yield, no more than 375 kg N/ha was justified; grass given this amount of N either as aqueous ammonia or as ‘Nitro-Chalk’ removed approximately 29 kg of N, 3 kg of P (7 kg P2O6), 26 kg of K (31 kg K2O) and 2 kg of Mg (3 kg MgO) per tonne of dry matter produced.

Discovery of two coloured Phylloceratidae belonging to the genus Adabofoloceras Joly, 1977. Hypotheses on the relationships between colour patterns of the shell and mode of life

2006 ◽  
Vol 177 (1) ◽  
pp. 51-59
Author(s):  
Bernard Jolyet ◽  
Cyril Baudouin
Keyword(s):  
Calcium Carbonate ◽  
Biological Function ◽  
The Other ◽  
Scientific Publications ◽  
Good Protection ◽  
New Findings ◽  
Mode Of Life ◽  
Colour Patterns

Abstract Until now the references of coloured specimens in the scientific publications about Juraphyllitidae, Phylloceratidae and Neophylloceratidae are not very numerous. The recent discovery of Adabofoloceras ardechicum (Munier-Chalmas, in Collot, 1880) and Adabofoloceras chantrei (Munier-Chalmas, in Collot, 1880) fills a part of this gap. The new findings allow to compare with coloured specimens published before, above all with the Calliphylloceras of the Kutch and with a Calliphylloceras demidoffi (Rousseau, 1842) of Upper Bathonian of Malagasy. Like every coloured specimen published before, the dark biochromes of the specimens studied in this note belong to the group of melanins. The other observable colours of both species of genus Adabofoloceras are in fact a schemochromy, that is an interferential phenomenon in the thin calcium carbonate layers; it does not imply the presence of biochromes. The exposure of the three studied specimens to UV shows the lack of biochromes such as porphyrins in these ammonites. The only biochromes found in these shells are probably melanins according to the works published earlier. In both Adabofoloceras, the colours are placed in radial stripes like “flames”, as in modern Nautilus. The Malagasy Calliphylloceras demidoffi shows that coloured longitudinal stripes can’t be excluded in the Phylloceratidae. It seams apropriate to compare the colours described in this note with those published before and with those of modern Nautilus in order to try to understand their biological function. The hypotheses proposed on the biological function of the ammonites shells colours are briefly explained and discussed. It is the same for Adabofoloceras ardechicum, the best example of coloured shells among Phylloceratidae known nowadays. We can think that these colours permitted a good protection against the predators by camouflage of the shell. It is possible to think that the biochromes could be made of excreted matter. It is more difficult to explain Calliphylloceras demidoffi because its colour is bad. Photos with IR films show biochromes in radial stripes and perhaps coloured longitudinal stripes. With most of the authors we can think that the biochromes were located in the most external layers of the test. Probably, first, they were excreted matter and secondly, they protected the animals against the predators.

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