The impact of soil structure and confining stress on the hydraulic conductivity of clays in brine environments

1992 ◽  
Vol 29 (5) ◽  
pp. 730-739 ◽  
Author(s):  
N. Yang ◽  
S. L. Barbour
Keyword(s):  
Electron Microscope ◽  
Sodium Chloride ◽  
Hydraulic Conductivity ◽  
Scanning Electron Microscope ◽  
Soil Structure ◽  
Confining Stress ◽  
Soil Structures ◽  
Initial Soil ◽  
Before And After ◽  
Scanning Electron

Numerous studies have been completed in recent years on the alteration of the hydraulic conductivity of clayey soils as a result of exposure to concentrated organic or inorganic permeants. These hydraulic conductivity changes have been attributed to either changes in microstructure, due to contraction of the diffuse double layer, or to the alteration of the macrostructure, as a result of volume changes leading to shrinkage fractures or fissures. In this paper, the change in hydraulic conductivity of a highly plastic natural clay during exposure to a concentrated sodium chloride (NaCl) solution is described. The performance of samples with three different initial soil structures, prepared by slurry, static compaction, and kneading compaction, were investigated under various levels of confining stress. Hydraulic conductivity tests were carried out before and after the samples were exposed to the NaCl solutions. Scanning electron microscope photography was used to compare the soil structures before and after brine permeation. The test results show that the alteration of hydraulic conductivity is strongly related to the initial soil structure and the level of confining stress. No significant change in the microfabric of the clay was observed; however, the size of the interaggregate pores appeared to increase as a result of the physicochemical volume change that occurred during brine permeation. The increase in hydraulic conductivity that occurred during brine permeation could be prevented by increasing the level of confining stress. The stress levels at which significant increases in hydraulic conductivity occurred appeared to be coincident with low levels of vertical stress which allowed the sample to undergo lateral shrinkage and a subsequent loss of confinement. Key words : hydraulic conductivity, clay soils, osmotic consolidation, sodium chloride brine, soil structure, scanning electron microscope.

scholarly journals Effect of Particle Size on the Wear Property of Magnetorheological Fluid

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Qiuxiang Zhang ◽  
Xinhua Liu ◽  
Yankun Ren ◽  
Lifeng Wang ◽  
Yuan Hu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Magnetorheological Fluid ◽  
Test Methods ◽  
Wear Property ◽  
Preparation Process ◽  
Before And After ◽  
Effect Of Particle Size ◽  
Scanning Electron

Aiming to study the effect of particle size on the wear property of magnetorheological fluid (MRF), experiment materials, preparation process, and test methods are elaborated, and three different MRF samples consisting of particles of different size are prepared. Test experiments are carried out and the effect of particle size on the wear property of MRF is discussed. Moreover, the microstructures of particles extracted from MRF obtained before and after the wear experiments are observed by scanning electron microscope (SEM). Experimental results show that the particle size has a significant effect on wear property of MRF. Furthermore, the MRF with particles of 1.5–2.8 μm diameter on average is good for the requirement of engineering applications.

Precipitation Characteristics of CaCO3 Scaling on Stainless Steel in Cooling Tower Condition

2012 ◽  
Vol 226-228 ◽  
pp. 1029-1033
Author(s):  
Jian Sheng ◽  
Hua Zhang
Keyword(s):  
Stainless Steel ◽  
Electron Microscope ◽  
Surface Energy ◽  
Scanning Electron Microscope ◽  
Heat Exchangers ◽  
Cooling Tower ◽  
Precipitation Characteristics ◽  
Stainless Steel 304 ◽  
Before And After ◽  
Scanning Electron

Stainless steel 304 and 316 (ss304 and ss316) are widely used in heat exchangers, and the precipitation characteristics of CaCO3 is the first step to research anti-fouling technology. CaCO3 scaling precipitated on coupons from 1.0mmol/l CaCO3 solution at 35°C. By weighing the coupons before and after static reaction experiments to get the mass of scaling and the morphology was taken by Scanning Electron Microscope (SEM). The results show that at the same condition there is more fouling on ss304 than ss316. Higher pH not only promotes square aragonite and calcite and square aragonite gradually recrystallize to calcite but also makes both homogeneous and heterogeneous nucleation rate increasing, and the former increases more, so the fouling mass is bigger at lower pH than higher pH; fouling grows at the place with higher surface energy first and then extend to surrounding place, and when the number increases and crystals grow big and connect each other to form fouling layer.

scholarly journals Evaluation of novel cleaning systems on mock-ups of unvarnished oil paint and chalk-glue ground within the Munch Aula Paintings Project

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Lena Porsmo Stoveland ◽  
Tine Frøysaker ◽  
Maartje Stols-Witlox ◽  
Terje Grøntoft ◽  
Calin Constantin Steindal ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Atmospheric Pollution ◽  
Surface Cleaning ◽  
Soft Particle ◽  
Oil Paintings ◽  
Before And After ◽  
History Of ◽  
Analytical Assessment ◽  
Scanning Electron

AbstractLow-risk removal of embedded surface soiling on delicate heritage objects can require novel alternatives to traditional cleaning systems. Edvard Munch’s monumental Aula paintings (1911–16) have a long history of exposure to atmospheric pollution and cleaning campaigns that have compromised the appearance and the condition of these important artworks. Soiling removal from porous and water-sensitive, unvarnished oil paintings continues to be a major conservation challenge. This paper presents the approach and results of research into the effect and efficiency of three novel systems used for soiling removal: soft particle blasting, CO2-snow blasting, and Nanorestore Gel® Dry and Peggy series hydrogels. Cleaning tests were performed on accelerated-aged and artificially soiled mock-ups consisting of unvarnished oil paint and chalk-glue grounds. Visual and analytical assessment (magnification using a light microscope and scanning electron microscope, as well as colour- and gloss measurement) was carried out before and after mock-up cleaning tests and the results were compared to those obtained using the dry polyurethane sponges employed in the most recent Aula surface cleaning campaign (2009–11). Although the results varied, the Nanorestore Gel® series proved promising with respect to improved soiling removal efficiency, and reduced pigment loss for the water-sensitive surfaces evaluated, compared to dry sponges.

Extraction of Oil Heteroatomic Compounds Using Metal Powders

2016 ◽  
Vol 685 ◽  
pp. 743-747 ◽  
Author(s):  
E.B. Golushkova ◽  
Alexander P. Ilyin ◽  
A.V. Mostovshchikov
Keyword(s):  
Thermal Decomposition ◽  
Electron Microscope ◽  
Ir Spectroscopy ◽  
Scanning Electron Microscope ◽  
Metal Powders ◽  
Elemental Analyses ◽  
Before And After ◽  
Heteroatomic Compounds ◽  
Scanning Electron

The paper presents results of scanning electron microscope (SEM) investigations, differential thermal and elemental analyses, and infrared (IR) spectroscopy of micron powders obtained by thermal decomposition of cupric and nickel oxalates before and after their blending with oil. The oil treatment modifies the powder compositions, heteroorganic compounds extracted from oil are observed on their surface. The analysis shows that materials based on copper and nickel micron powders can be used for the prepurification of crude hydrocarbons from heteroatomic compounds.

The microscopic examination of the structure of sub-surface horizons of soils

1976 ◽  
Vol 8 (6) ◽  
pp. 348-354 ◽  
Author(s):  
P Bullock ◽  
C P Murphy
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Microscopic Examination ◽  
Soil Structure ◽  
Thin Sections ◽  
X Ray ◽  
Cultural Conditions ◽  
Structural Types ◽  
Scanning Electron

What is meant by “soil structure”? Microscopic examination of thin sections of soil, using such instruments as the polarising microscope, X-ray diffractometer and scanning electron microscope has enabled a classification of the components of soils and their structural types to be built up. Now with the aid of the image-analysing computer these components can be quantified rapidly, characteristics may be calculated and their behaviour under varying cultural conditions predicted.

Laboratory Tests on the Improvement of Strength of Silt Using Microbes

2012 ◽  
Vol 166-169 ◽  
pp. 1620-1625
Author(s):  
Zhao Yang Xu ◽  
Shao Jin Wan ◽  
Yao Ren Ma
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Compression Test ◽  
Laboratory Tests ◽  
Triaxial Compression ◽  
Energy Dispersive ◽  
X Ray ◽  
Metabolic Outcomes ◽  
Before And After ◽  
Scanning Electron

Microbe technology is introduced for improving silt The metabolic outcomes and precipitation of microbes can glue the soil granule,plug mineral lattice crystal,simultaneously strengthen their shear resistance.Characteristics of silt before and after modification are compared by CU triaxial compression test. By Scanning Electron Microscope(ESEM) and Energy Dispersive X-ray(EDX),the modification mechanism of silt has been investigated.The results show that the values φ of silt is increased larger modified by carbonate mineralization microbes, while the value of cohesion increases larger by polysaccharides viscose microbes.

Study on the State Change of Ir/Al2O3 Catalyst by Decomposition of Ammonium Dinitramide (ADN) Based Low-Toxicity Monopropellant

2020 ◽  
Vol 20 (9) ◽  
pp. 5780-5782
Author(s):  
Jincheol Kim ◽  
Yeongmin Jo ◽  
Jonggi Jeon ◽  
Taegyu Kim
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Decomposition Reaction ◽  
The State ◽  
State Change ◽  
Ammonium Dinitramide ◽  
Before And After ◽  
Low Toxicity ◽  
Al2o3 Catalyst ◽  
Scanning Electron

The change of the Ir/Al2O3 catalyst before and after the reaction with ADN based low-toxicity monopropellant was confirmed. The catalyst were recovered after decomposition reaction with propellant in a monopropellant thruster at 350 °C preheating condition. Catalyst analysis was performed using a scanning electron microscope (SEM) and Brunauer-Emmett-Teller (BET) analyzer. The change of the catalyst specific devices.

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