Predicting the precipitated calcium carbonate and unconfined compressive strength of bio-mediated sands through robust hybrid optimization algorithms

Transportation Geotechnics, Год журнала: 2024, Номер 46, С. 101235 - 101235

Опубликована: Март 29, 2024

Язык: Английский

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Role of bacteria on bio-induced calcium carbonate formation: insights from droplet microfluidic experiments

Géotechnique, Год журнала: 2024, Номер unknown, С. 1 - 13

Опубликована: Июль 8, 2024

Microbially induced calcium carbonate precipitation (MICP) has emerged as a promising solution for geotechnical issues. However, the role of bacteria in formation (CaCO 3 ) remains incompletely understood. In this study, droplet microfluidic chip was developed to observe growth process and bacterial behaviour during MICP under various density conditions. Scanning electron microscope then utilised analyse morphology, Raman spectroscopy employed identify polymorphs. Nucleation within microspaces showed stochastic nature. Within droplets where crystals formed, all manifested cubic calcite. Higher led larger more irregularly shaped crystals, with crystal size showing significant correlation urease activity. no higher activity resulted amorphous on surface. pattern differed from monocrystalline carbonate. The results demonstrate that act primarily secretors regulate process, while their nucleation sites debatable. This study provides new insights into bio-induced mechanism.

Язык: Английский

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Temperature-Dependent SWCC Model for Unsaturated Soil

International Journal of Geomechanics, Год журнала: 2024, Номер 24(5)

Опубликована: Фев. 29, 2024

The soil–water characteristic curve (SWCC) model considering the temperature effect is significant in precisely predicting relationship between matric suction and degree of saturation unsaturated soils geotechnical geoenvironmental engineering. In this work, we derived a new temperature-dependent wetting coefficient, incorporating nonlinear enthalpy immersion per unit area. We introduce simplified expression that successfully approximates coefficient for temperatures 273.15 373.15 K. addition, propose equation SWCC model. comprehensively considers sensitivities water–air interface tension which shows an increase given leads to decrease saturation. results illustrate suitable nonisothermal soils.

Язык: Английский

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Undrained cyclic responses of biocemented calcareous silty sand

Acta Geotechnica, Год журнала: 2024, Номер 19(10), С. 6683 - 6690

Опубликована: Апрель 26, 2024

Язык: Английский

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Regulating the Process of Microbially Induced Calcium Carbonate Precipitation through Applied Electric Fields: Evidence and Insights Using Microfluidics

Journal of Geotechnical and Geoenvironmental Engineering, Год журнала: 2024, Номер 150(10)

Опубликована: Июль 25, 2024

Язык: Английский

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Microscale insights into enzyme-induced carbonate precipitation in rock-based microfluidic chips

Géotechnique, Год журнала: 2024, Номер unknown, С. 1 - 12

Опубликована: Авг. 5, 2024

Biomineralisation technology shows promise for sealing subsurface fractures, but understanding its microscale mechanisms in real rock fractures remains incomplete. In this study, a microfluidic chip incorporating slices was utilised to conduct enzymatically induced carbonate precipitation (EICP) experiments using one-phase continuous injection strategy. Real-time observations revealed grey flocs forming and clustering into aggregates susceptible transport by flow. Calcium (CaCO 3 ) crystals that formed on polydimethylsiloxane surfaces effectively filled bridged leading significant pressure drop. Rough can provide additional sites solute attachment heterogeneous nucleation of calcium carbonate. High velocities small apertures generally promoted floc formation reduced crystal growth. Precipitation content gradually increased with decreasing rate. Lower estimated efficiency obtained smaller, high-flow fractures. Precipitates interfaces eddies drops within narrow pore throats. Crystal growth displayed two-stage development: an initial increase followed decrease, varying across different facets (the or orientations the growing crystals). Growth competition will occur when two more neighbouring come contact diverse grain orientations. The findings valuable insights processes governing EICP contributing evaluation efficacy fracture applications.

Язык: Английский

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Experimental Analyses of Pore‐Size Dependent Biomineralization in Porous Media Under Various Flow Rate and Bacterial Density Scenarios

Water Resources Research, Год журнала: 2025, Номер 61(1)

Опубликована: Янв. 1, 2025

Abstract We document results of a set laboratory experiments aimed at exploring impacts injection rate and bacterial density on biomineralization across water‐saturated porous media. The study relies Low‐Field Nuclear Magnetic Resonance technology the ensuing transverse spin‐spin relaxation time distributions. latter is documented to provide robust quantification temporal histories pore size distributions during biomineralization. As such, our work explores quantifies pore‐size dependent three‐dimensional space. also provides quantitative analysis alterations in porosity permeability induced by biomineralization, together with (time‐averaged) rates volume change. A plugging ratio efficiency index introduced quantify strength pore‐size‐related Our reveal that induces significant distribution within medium, these changes being modulated rate. find CaCO 3 mainly precipitates macropores, consistent presence favorable local hydrodynamic conditions large surface areas therein. Precipitated found increase density. High densities amplify change macropores adequate contribute reduction. Otherwise, diminished mesopores micropores for highest considered.

Язык: Английский

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Particle size effect on unconfined compressive strength of biotreated sand

Transportation Geotechnics, Год журнала: 2023, Номер 42, С. 101092 - 101092

Опубликована: Авг. 22, 2023

Язык: Английский

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Discussion: Embracing microfluidics to advance environmental science and technology

The Science of The Total Environment, Год журнала: 2024, Номер 937, С. 173597 - 173597

Опубликована: Май 27, 2024

Язык: Английский

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Psychrophiles to control ice-water phase changes in frost-susceptible soils

Scientific Reports, Год журнала: 2024, Номер 14(1)

Опубликована: Янв. 4, 2024

Abstract The phase changes of soil water or porous media have a crucial influence on the performance natural and man-made infrastructures in cold regions. While various methods been explored to address impacts frost-action arising from these changes, conventional approaches often rely chemicals, mechanical techniques, reuse waste materials, which exhibit certain limitations environmental concerns. In contrast, organisms produce ice-binding proteins (IBPs) antifreeze (AFPs) adapt low temperatures, can inhibit ice crystal growth by lowering freezing point preventing crystallization without need for external intervention. This study explores potential three psychrophilic microbes: Sporosarcina psychrophile , globispora Polaromonas hydrogenivorans induce non-equilibrium depression thermal hysteresis order control lens frost-susceptible soils. We hypothesize that AFPs produced psychrophiles will alter profiles microbes, concentration released extracellular solution, properties protein-mixed soils are monitored at an interval days. controlled showed − 4.59 °C 4.62 °C, whereas protein-treated maximum 8.54 7.71 °C. Interestingly, except sample, all samples were thawed negative temperature (minimum recorded 0.85 °C). Further analysis treated compared mixed freeze (1.25 vs. 0.51 °C) thaw (2.75 1.72 extensive gap. thawing gap is difference between beginning core formation completed frozen, selected different incubation Overall, this presents novel bio-mediated approach using microbes

Язык: Английский

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