Impact of the Kinetics of Salt Crystallization on Stone Damage During Rewetting/Drying and Humidity Cycling

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Julie Desarnaud ◽  
François Bertrand ◽  
Noushine Shahidzadeh-Bonn
Keyword(s):  
Sodium Sulfate ◽  
Phase Contrast ◽  
Sulfate Solution ◽  
Salt Crystallization ◽  
Severe Damage ◽  
Contrast Microscopy ◽  
Salt Crystals ◽  
High Concentrations ◽  
The Impact ◽  
Kinetics Of

In this study, we show that the key to understand why the same salt can cause damage in some conditions and not in others is the kinetics of crystallization. We present experiments assessing the impact of the recrystallization dynamics of sodium sulfate on damage observed in sandstone after repeated cycles of rewetting/drying and humidification/drying. Macroscopic and microscopic scale experiments using magnetic resonance imaging and phase contrast microscopy demonstrate that sodium sulfate that has both hydrated and anhydrous phases can lead to severe damage in sandstone during rewetting/drying cycles, but not during humidity cycling. During rewetting (a rapid process) in regions (pores) that are highly concentrated in salt, anhydrous microcrystals dissolve only partially, giving rise to a heterogeneous salt solution that is supersaturated with respect to the hydrated phase. The remaining anhydrous crystals then act as seeds for the formation of large amounts of hydrated crystals, creating grape-like structures that expand rapidly. These clusters can generate stresses larger than the tensile strength of the stone, leading to damage. On the other hand, with humidification (a slow process) and after complete deliquescence of salt crystals, the homogeneous sodium sulfate solution can reach high concentrations during evaporation without any nucleation, favoring the formation of isolated anhydrous crystals (thenardite). The crystallization of the anhydrous salt generates only very small stresses compared to the hydrated clusters and therefore causes hardly any damage to the stone.

Modeling the Germination Kinetics of Clostridium botulinum 56A Spores as Affected by Temperature, pH, and Sodium Chloride†

2000 ◽  
Vol 63 (8) ◽  
pp. 1071-1079 ◽  
Author(s):  
FABIOLA P. CHEA ◽  
YUHUAN CHEN ◽  
THOMAS J. MONTVILLE ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Sodium Chloride ◽  
Clostridium Botulinum ◽  
Phase Contrast ◽  
Brain Heart Infusion ◽  
Exponential Parameter ◽  
Contrast Microscopy ◽  
Microscopy Data ◽  
Fail Safe ◽  
Kinetics Of ◽  
Validation Experiments

The germination kinetics of proteolytic Clostridium botulinum 56A spores were modeled as a function of temperature (15, 22, 30°C), pH (5.5, 6.0, 6.5), and sodium chloride (0.5, 2.0, 4.0%). Germination in brain heart infusion (BHI) broth was followed with phase-contrast microscopy. Data collected were used to develop the mathematical models. The germination kinetics expressed as cumulated fraction of germinated spores over time at each environmental condition were best described by an exponential distribution. Quadratic polynomial models were developed by regression analysis to describe the exponential parameter (time to 63% germination) (r2 = 0.982) and the germination extent (r2 = 0.867) as a function of temperature, pH, and sodium chloride. Validation experiments in BHI broth (pH: 5.75, 6.25; NaCl: 1.0, 3.0%; temperature: 18, 26°C) confirmed that the model's predictions were within an acceptable range compared to the experimental results and were fail-safe in most cases.

scholarly journals Deterioration Regularity of Sodium Sulfate Solution Attack on Cemented Coal Gangue-Fly Ash Backfill under Drying-Wetting Cycles

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shaojie Chen ◽  
Zhen Zhang ◽  
Dawei Yin ◽  
Junbiao Ma
Keyword(s):  
Fly Ash ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Coal Gangue ◽  
Salt Crystallization ◽  
Sodium Sulfate Solution ◽  
Sulfate Ion ◽  
Sulfate Ions ◽  
Ion Contents ◽  
The Masses

To research the properties of cemented coal gangue-fly ash backfill (CGFB) exposed to different concentrations of sodium sulfate solutions under drying-wetting cycles, the mass changes, uniaxial compressive strengths, sulfate ion contents at different depths, and microstructures of CGFB samples were measured in this study. The results show that the CGFB samples were damaged by salt crystallization in the dry state and attacked by the expansive products in the wet state. The sulfate ion contents in CGFB samples increased with the sulfate concentrations and drying-wetting cycles and decreased from the surface to the inside of the samples. The damage process of CGFB samples evolved from the surface to the inside. In the early stage of corrosion, sulfate ions adsorbed to the surface of CGFB samples and consumed nonhydrated particles to form acicular ettringite and other products that filled the material pores. For this stage, the driving force of sulfate ions to enter into the CGFB samples was the highest for the samples immersed in 15% sodium sulfate solution, and the masses and strengths increased the fastest. As the drying-wetting cycles continued, the nonhydrated particles inside the samples were nearly completely hydrated, and the samples were constantly damaged by salt crystallization and dissolution. The corrosion ions entered into the samples and consumed portlandite to produce a large amount of prismatic ettringite and aggravated the internal corrosion of CGFB samples. At the fifteenth drying-wetting cycle, the higher the salt concentration of the immersion solution was, the faster the masses and the strengths of CGFB samples decreased. Moreover, the surface spalling and failure of CGFB samples were more severe.

Study in Kinetics of Barium Sulfate Crystallization Process of Oilfield Injection

2014 ◽  
Vol 962-965 ◽  
pp. 757-761
Author(s):  
Bei Yang ◽  
Xiang Zhang ◽  
Xin Ge Shi ◽  
Jia Neng Guo ◽  
Qi Wei Wang ◽  
...  
Keyword(s):  
Sodium Sulfate ◽  
Barium Sulfate ◽  
Crystallization Process ◽  
Conductivity Measurement ◽  
Barium Chloride ◽  
Sulfate Solution ◽  
Conductivity Equation ◽  
Measuring Device ◽  
Conductivity Curve ◽  
Kinetics Of

With conductivity measurement in different concentrations of barium chloride, sodium sulfate, sodium chloride solution, their concentration-conductivity equation is obtained. Through mathematical conversion, the relation between sulfuric acid root ion in the solution, barium ion conductivity and the concentration is showed as: X=4.1744×10-6Y-6.8544×10-5,which is used to reflect the undissolved salt barium sulfate crystallization in the solution. Conductivity online measuring device is established, which can Intermittently test barium chloride, sodium sulfate solution of different concentrations, and detect the change of electrical conductivity in the process of crystallization of homogeneous barium sulfate in real-time. the different stages of crystallization process is determined by analysis of the conductivity curve. Through data processing to concert concentration into conductivity, so that the kinetic equation of barium sulfate crystallization process are obtained.

Cellular transplantation for the nervous system: impact of time after preparation on cell viability and survival

2010 ◽  
Vol 113 (3) ◽  
pp. 666-672 ◽  
Author(s):  
Glenn T. Gobbel ◽  
Douglas Kondziolka ◽  
Wendy Fellows-Mayle ◽  
Martin Uram
Keyword(s):  
Phase Contrast ◽  
Neural Progenitor Cells ◽  
Clinical Trial Design ◽  
Fluorescent Dye ◽  
Tissue Preparation ◽  
Phase Contrast Microscopy ◽  
Adult Mice ◽  
Cellular Transplantation ◽  
Contrast Microscopy ◽  
The Impact

Object Cell transplantation has shown promise for the treatment of various neurological disorders, but the factors that influence cell survival and integration following transplantation are poorly understood. In fact, little is known regarding how simple but potentially critical variables, including the method of cellular preparation and administration, might affect transplant success. The goal of the present study was to determine the impact of time between tissue preparation and implantation on cellular viability. Time can vary with cell preparation, delivery to the operating room, and surgical technique. This study was also designed to evaluate the sensitivity of various methods of assessing implant viability. Methods Cell lines of neural progenitor cells and bone marrow stromal cells were generated from healthy adult mice. On the day of experimentation, the cells were collected, suspended in a balanced salt solution, and sequentially assessed for viability for up to 3.5 hours based on their appearance under phase-contrast microscopy, their ability to retain a fluorescent dye, and their attachment to a cultivation surface for 24 hours. Results When viability was measured based on the ability of cells to retain a fluorescent dye, there was a decrease in viability of 10–15% each hour. Based on the ability of the cells to attach to a culture surface and grow for 24 hours, viability decreased more rapidly at approximately 20% per hour. In addition, only about one-third of the cells judged viable based on phase-contrast microscopy or acute dye retention were found to be viable based on plating, and only 10% of the cells initially judged as viable were still capable of survival after 3 hours in suspension. Conclusions The authors' results indicate that that there can be significant losses in viability between preparation and implantation and that more sophisticated methods of evaluation, such as the ability of cells to attach to a substrate and grow, may be required to detect decreases in viability. The time between preparation and implantation will be an important factor in clinical trial design.

A simple glycerol-based freezing protocol for the semen of a marsupial Trichosurus vulpecula, the common brushtail possum

1991 ◽  
Vol 3 (2) ◽  
pp. 119 ◽  
Author(s):  
JC Rodger ◽  
SJ Cousins ◽  
KE Mate
Keyword(s):  
Phase Contrast ◽  
Frozen Storage ◽  
Neck Region ◽  
Vapour Phase ◽  
Brushtail Possum ◽  
Freezing And Thawing ◽  
Contrast Microscopy ◽  
Successful Technique ◽  
The Common ◽  
High Concentrations

Frozen storage of semen and embryos is now a well established part of the breeding of many eutherian mammals but it has not been applied to marsupials. This paper reports the first successful technique for the frozen preservation of marsupial spermatozoa. Semen was collected by electroejaculation under anaesthesia from a pool of five brushtail possums. The ejaculated semen was diluted 1:1 with Krebs Henseleit Ringer, centrifuged at 800 g for 5 min, resuspended in the test cryoprotectant media at 1, 2 and 5 x 10(6) spermatozoa mL-1 and 7, 10.5, 14 and 17.5% glycerol and then drawn up into 0.25 mL plastic straws. The spermatozoa were rapidly frozen in the vapour phase, 6 cm above liquid nitrogen, for 30 min before the straws were plunged into the liquid. Sperm motility was assessed blind for coded straws by phase-contrast microscopy on a warmed stage (35 degrees C), before freezing and after rapid thawing in a water bath at 37 degrees C (10 s). The highest recovery of both percentage motility (around 50-60%) and progressive motility (around 0.5-1 unit lower than prefreeze) occurred when spermatozoa were frozen and thawed in the presence of 17.5% glycerol. Recovery of motility was greater at the higher sperm concentrations (2 and 5 x 10(6) mL-1). There was no evidence of acrosomal damage or loss after freezing and thawing in high concentrations of glycerol. The only defect detected in spermatozoa subjected to the protocol was a variable tendency to bending of the neck region. This ranged from heads inclined at a slight angle to the tail through to complete flexure.(ABSTRACT TRUNCATED AT 250 WORDS)

Detachment of biofilm bacteria due to variations in nutrient supply

1998 ◽  
Vol 37 (4-5) ◽  
pp. 211-214 ◽  
Author(s):  
Linda K. Sawyer ◽  
Slawomir W. Hermanowicz
Keyword(s):  
Phase Contrast ◽  
Digital Image Analysis ◽  
Specific Growth ◽  
Nutrient Supply ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Nutrient Limitations ◽  
Contrast Microscopy ◽  
Biofilm Bacteria ◽  
Observable Parameter

Growth and detachment rates of an environmental isolate of Aeromonas hydrophila attached to a surface were determined under varying nutrient supply conditions in a complex medium. Growth and detachment of cells were observed in real time using phase contrast microscopy in glass parallel plate flow chambers. Surface shear stress was controlled in all experiments at 3 N m−2. Images were taken every 15 min. Digital image analysis was used to determine specific growth and detachment rates. An observable parameter proportional to the nutrient depletion at the surface due to transfer limitations was used to indicate nutrient limitations. Specific detachment rates increased as the depletion parameter increased, indicating that nutrient limitations cause this bacterium to detach at greater rates.

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