Laboratory experiments on swelling due to crystal growth in sulphate argillaceous rocks

2013 ◽  
pp. 365-372 ◽  
Keyword(s):  
Crystal Growth ◽  
Laboratory Experiments ◽  
Argillaceous Rocks

scholarly journals Formation of C-A-S-H phases from the interaction between concrete or cement and bentonite

Clay Minerals ◽  
2016 ◽  
Vol 51 (2) ◽  
pp. 223-235 ◽  
Author(s):  
Raúl Fernández ◽  
Ana Isabel Ruiz ◽  
Jaime Cuevas
Keyword(s):  
Calcium Silicate Hydrate ◽  
Laboratory Experiments ◽  
Pore Scale ◽  
Lime Mortar ◽  
Cement Interface ◽  
Argillaceous Rocks ◽  
Deep Geological Disposal ◽  
Engineered Barriers ◽  
High Level ◽  
Increasing Temperature

AbstractConcrete and bentonite are being considered as engineered barriers for the deep geological disposal of high-level radioactive waste in argillaceous rocks. Three hydrothermal laboratory experiments of different scalable complexity were performed to improve our knowledge of the formation of calcium aluminate silicate hydrates (C-A-S-H) at the interface between the two materials: concretebentonite transport columns, lime mortar-bentonite transport columns and a portlandite- (bentonite and montmorillonite) batch experiment. Precipitation of C-A-S-H was observed in all experiments. Acicular and fibrous morphologies with certain laminar characteristics were observed which had smaller Ca/Si and larger Al/Si ratios with increasing temperature and lack of accessory minerals. The compositional fields of these C-A-S-H phases formed in the experiments are consistent with Al/(Si+Al) ratios of 0.2– 0.3 described in the literature. The most representative calcium silicate hydrate (C-S-H) phase from the montmorillonite–cement interface is Al-tobermorite. Structural analyses revealed a potential intercalation or association of montmorillonite and C-A-S-H phases at the pore scale.

scholarly journals Orientation Fabrics in Lake Ice

1962 ◽  
Vol 4 (33) ◽  
pp. 367-370 ◽  
Author(s):  
J. B. Lyons ◽  
R. E. Stoiber
Keyword(s):  
Crystal Growth ◽  
Laboratory Experiments ◽  
Thermal Flux ◽  
Thick Layer ◽  
Supercooled Water ◽  
Field Observations ◽  
Lake Ice ◽  
Geometric Factors ◽  
Mechanical Fragmentation ◽  
Crystallographic Orientations

AbstractLaboratory experiments and field observations permit an explanation of the varying crystallographic orientations observed in lake ice in terms of four factors: (1) coincidence of the plane of most rapid growth in ice (the basal plane) with the vector of thermal flux, (2) mechanical fragmentation of early-formed dendrites and plates by winds above a critical velocity (approximately 2.7 m./sec.), (3) the presence of a sufficiently thick layer of supercooled water to permit vertical crystal growth, and (4) the operation of geometric factors, first pointed out by Perey and Pounder, which result in the gradual elimination of the flatter plates of growing ice by the steeper ones.

scholarly journals The steady-state crystal size of deforming ice

1994 ◽  
Vol 20 ◽  
pp. 13-18 ◽  
Author(s):  
T.H. Jacka ◽  
Li Jun
Keyword(s):  
Crystal Growth ◽  
Steady State ◽  
Temperature Effects ◽  
Crystal Orientation ◽  
Laboratory Experiments ◽  
Crystal Size ◽  
Large Strains ◽  
Polar Ice ◽  
Temperature Dependent ◽  
Arrhenius Relation

Previous studies have established that, together with the development of a preferred crystal-orientation fabric in ice undergoing creep deformation to high strains, there also develops a tertiary equilibrium crystal size, i.e. the crystal size, rather than affecting the creep rate, is a result of the deformation to large strains.Equilibrium crystal size is considered here as a “balance” between crystal growth with time as a function of temperature and crystal change as a result of temperature dependent deformation. The temperature effects in these two processes (Arrhenius relation) are similar and consideration of the activation energies for the two processes indicates that it may be appropriate to cancel them, yielding a dependence of equilibrium crystal size on stress alone. The results from laboratory experiments of steady-state crystal size plotted as a function of stress support the above proposition.The possibility of using the relationships between steady-state crystal size and deviatoric stress as a polar ice-mass piezometer is discussed.

scholarly journals Orientation Fabrics in Lake Ice

1962 ◽  
Vol 4 (33) ◽  
pp. 367-370 ◽  
Author(s):  
J. B. Lyons ◽  
R. E. Stoiber
Keyword(s):  
Crystal Growth ◽  
Laboratory Experiments ◽  
Thermal Flux ◽  
Thick Layer ◽  
Supercooled Water ◽  
Field Observations ◽  
Lake Ice ◽  
Geometric Factors ◽  
Mechanical Fragmentation ◽  
Crystallographic Orientations

AbstractLaboratory experiments and field observations permit an explanation of the varying crystallographic orientations observed in lake ice in terms of four factors: (1) coincidence of the plane of most rapid growth in ice (the basal plane) with the vector of thermal flux, (2) mechanical fragmentation of early-formed dendrites and plates by winds above a critical velocity (approximately 2.7 m./sec.), (3) the presence of a sufficiently thick layer of supercooled water to permit vertical crystal growth, and (4) the operation of geometric factors, first pointed out by Perey and Pounder, which result in the gradual elimination of the flatter plates of growing ice by the steeper ones.

scholarly journals Self-preservation strategies during bacterial biomineralization with reference to hydrozincite and implications for fossilization of bacteria

2014 ◽  
Vol 11 (100) ◽  
pp. 20140845 ◽  
Author(s):  
Bryne T. Ngwenya ◽  
Marisa Magennis ◽  
Francesca Podda ◽  
Andrei Gromov
Keyword(s):  
Crystal Growth ◽  
Calcium Carbonate ◽  
Laboratory Experiments ◽  
Extracellular Polymeric Substances ◽  
High Porosity ◽  
Effective Mechanism ◽  
Metabolite Exchange ◽  
Open Question ◽  
Sphere Formation

The induction of mineralization by microbes has been widely demonstrated but whether induced biomineralization leads to distinct morphologies indicative of microbial involvement remains an open question. For calcium carbonate, evidence suggests that microbial induction enhances sphere formation, but the mechanisms involved and the role of microbial surfaces are unknown. Here, we describe hydrozincite biominerals from Sardinia, Italy, which apparently start life as smooth globules on cyanobacterial filaments, and evolve to spheroidal aggregates consisting of nanoplates. Complementary laboratory experiments suggest that organic compounds are critical to produce this morphology, possibly by inducing aggregation of nanoscopic crystals or nucleation within organic globules produced by metabolizing cells. These observations suggest that production of extracellular polymeric substances by microbes may constitute an effective mechanism to enhance formation of porous spheroids that minimize cell entombment while also maintaining metabolite exchange. However, the high porosity arising from aggregation-based crystal growth probably facilitates rapid oxidation of entombed cells, reducing their potential to be fossilized.

Inexpensive laboratory experiments on crystal growth of water soluble substances in gel media

1992 ◽  
Vol 69 (2) ◽  
pp. A47 ◽  
Author(s):  
R. P. Rastogi ◽  
Ishwar Das ◽  
Anal Pushkarna ◽  
Archana Sharma ◽  
Kiran Jaiswal ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Laboratory Experiments ◽  
Water Soluble

scholarly journals Influence of the ice growth rate on the incorporation of gaseous HCl

2004 ◽  
Vol 4 (11/12) ◽  
pp. 2513-2519 ◽  
Author(s):  
F. Domine ◽  
C. Rauzy
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Growth Mechanism ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Ice Growth ◽  
A Value ◽  
Physical Variables ◽  
Hcl Concentration ◽  
Cloud Ice

Abstract. Ice crystals were grown in the laboratory at −15°C, at different growth rates and in the presence of a partial pressure of HCl of 1.63×10-3 Pa, to test whether the ice growth rate influences the amount of HCl taken up, XHCl, as predicted by the ice growth mechanism of Domine and Thibert (1996). The plot of HCl concentration in ice as a function of growth rate has the aspect predicted by that mechanism: XHCl decreases with increasing growth rate, from a value that depends on thermodynamic equilibrium to a value that depends only on kinetic factors. The height of the growth steps of the ice crystals is determined to be about 150 nm from these experiments. We discuss that the application of these laboratory experiments to cloud ice crystals and to snow metamorphism is not quantitatively possible at this stage, because the physical variables that determine crystal growth in nature, and in particular the step height, are not known. Qualitative applications are attempted for HCl and HNO3 incorporation in cloud ice and snowpack crystals.

Crystallization of Pentaerythritol II. Model Experiments

1994 ◽  
Vol 59 (6) ◽  
pp. 1270-1278 ◽  
Author(s):  
Miloslav Karel ◽  
Jaroslav Nývlt ◽  
Angelo Chianese
Keyword(s):  
Crystal Growth ◽  
Laboratory Experiments ◽  
Secondary Nucleation ◽  
Mixed Product ◽  
Model Experiments ◽  
Product Removal ◽  
Mixed Suspension ◽  
Kinetics Of ◽  
Kinetics Of Crystal Growth

Kinetics of crystallization of the pentaerythritol has been determined in laboratory experiments: MSMPR (Mixed Suspension Mixed Product Removal) crystallizer experiments served for determination of the kinetics of secondary nucleation and of the kinetics of crystal growth.

scholarly journals Influence of the ice growth rate on the incorporation of gaseous HCl

2004 ◽  
Vol 4 (4) ◽  
pp. 4719-4736 ◽  
Author(s):  
F. Domine ◽  
C. Rauzy
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Growth Mechanism ◽  
Laboratory Experiments ◽  
Ice Crystals ◽  
Ice Growth ◽  
A Value ◽  
Physical Variables ◽  
Hcl Concentration ◽  
Cloud Ice

Abstract. Ice crystals were grown in the laboratory at −15°C, at different growth rates and in the presence of a partial pressure of HCl of 1.63×10−3 Pa, to test whether the ice growth rate influences the amount of HCl taken up, XHCl, as predicted by the ice growth mechanism of Domine and Thibert (1996). The plot of HCl concentration in ice as a function of growth rate has the aspect predicted by that mechanism: XHCl decreases with increasing growth rate, from a value that depends on thermodynamic equilibrium to a value that depends only on kinetic factors. The height of the growth steps of the ice crystals is determined to be about 1.5 nm from these experiments. We discuss that the application of these laboratory experiments to cloud ice crystals and to snow metamorphism is not quantitatively possible at this stage, because the physical variables that determine crystal growth in nature, and in particular the step height, are not known. Qualitative applications are attempted for HCl and HNO3 incorporation in cloud ice and snowpack crystals.

scholarly journals The steady-state crystal size of deforming ice

1994 ◽  
Vol 20 ◽  
pp. 13-18 ◽  
Author(s):  
T.H. Jacka ◽  
Li Jun
Keyword(s):  
Crystal Growth ◽  
Steady State ◽  
Temperature Effects ◽  
Crystal Orientation ◽  
Laboratory Experiments ◽  
Crystal Size ◽  
Large Strains ◽  
Polar Ice ◽  
Temperature Dependent ◽  
Arrhenius Relation

Previous studies have established that, together with the development of a preferred crystal-orientation fabric in ice undergoing creep deformation to high strains, there also develops a tertiary equilibrium crystal size, i.e. the crystal size, rather than affecting the creep rate, is a result of the deformation to large strains.Equilibrium crystal size is considered here as a “balance” between crystal growth with time as a function of temperature and crystal change as a result of temperature dependent deformation. The temperature effects in these two processes (Arrhenius relation) are similar and consideration of the activation energies for the two processes indicates that it may be appropriate to cancel them, yielding a dependence of equilibrium crystal size on stress alone. The results from laboratory experiments of steady-state crystal size plotted as a function of stress support the above proposition.The possibility of using the relationships between steady-state crystal size and deviatoric stress as a polar ice-mass piezometer is discussed.

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