• Journal of the Korean Geosynthetics Society
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• v.1 no.1
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• pp.43-51
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• 2002

In this study, free swell index of betonite was examined in several regeants; distilled water, leachate, seawater and 3% NaCl solution. Free swell index values of bontonite to be added Poly(acrlylic acid), PYA(Polyvinyl Alcohol) or SCMC (Sodium Carboxymethyl Cellulose) were evaluated and compared. From this, it was confirmed that hydraulic conductivities of GCL in seawater were examined and the hydraulic conductivities of GCL in seawater were compared to those in distilled water. The average values of free swell indices of bentonite were decreased in order of distilled water>leachate>seawater. It was shown that no significant differences were occurred for free swell index between seawater and 3% NaCl solution. For bentonite to be added PVA, the other reagents except distilled water didn't affect increase of swelling. Swelling properties of bentonite to be added SCMC were improved except 3% NaCl solution.

• Geomechanics and Engineering
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• v.19 no.1
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• pp.21-28
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• 2019

Use of cement in stabilizing the sulfate-bearing clay soils forms ettringite/ thaumasite in the presence of moisture leads to excessive swelling and causes damages to structures built on them. The development and use of non-traditional stabilisers such as alkali activated ground granulated blast-furnace slag (AGGBS) and enzyme for soil stabilisation is recommended because of its lower cost and the non detrimental effects on the environment. The objective of the study is to investigate the effectiveness of AGGBS and enzyme on improving the volume change properties of sulfate bearing soil as compared to ordinary Portland cement (OPC). The soil for present study has been collected from Tilda, Chhattisgarh, India and 5000 ppm of sodium sulfate has been added. Various dosages of the selected stabilizers have been used and the effect on plasticity index, differential swell index and swelling pressure has been evaluated. XRD, SEM and EDX were also done on the untreated and treated soil for identifying the mineralogical and microstructural changes. The tests results show that the AGGBS and enzyme treated soil reduces swelling and plasticity characteristics whereas OPC treated soil shows an increase in swelling behaviour. It is observed that the swell pressure of the OPC-treated sulfate bearing soil became 1.5 times higher than that of the OPC treated non-sulfate soil.

• Geomechanics and Engineering
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• v.5 no.6
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• pp.565-574
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• 2013

Extensive study was carried out on Clay expansive soil. This soil was silty clay and can be classified as CH. The degree of expansion was found to range from low to medium depending on the free swell and swell pressure tests. The research investigated the effect of using cement dust on swelling potential, Atterberg Limit, linear shrinkage, and mineralogical composition of expansive soil. The results showed that the swelling potential, plasticity index, linear shrinkage, and clay minerals decrease with increasing cement dust percentage. The cement dust accumulates in huge amounts as a side product in cement factories, and the disposal of this fine dust is very difficult and poses an environmental threat.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.66-72
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• 2013

In this study, the thermal conductive characteristics and basic properties of the nine commercial products of bentonite grouts were studied. Six of the nine products for ground heat exchanger systems are imported and others for civil engineering are domestic. The thermal conductivities of all bentonite products are nearly similar among products. The free swell indexes, viscosities and filter losses of the ground heat exchanger grouts are lower than those of the civil engineering ones. These characteristics seem to increase of the fluidity to fill the bentonite slurry to bore-hall perfectly, rather than to prevent underground water penetration. Thus, the mixtures of bentonites and sands are recommended for high thermal conduction grouts.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.11a
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• pp.31-36
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• 1993

Three different methods were employed to measure the degree of aerial oxidation in coal and the resulting oxidation/weathering indices were applied to obtain kinetic parameters of aerial oxidation processes, The index (i.e., slurry pH, Free Swelling Index, weight gain) values were subjected to kinetic analysis based on power-law Arrhenius type reaction model. The results show that activation energy of the aerial oxidation in 20-29$0^{\circ}C$ is in the range of 12-16 ㎉/㏖ and the agreement among three techniques is remarkable. The first order kinetic model is suitable in describing low temperature aerial oxidation process, except in the FSI case where the zero order expression is the best one.

• Journal of the Mineralogical Society of Korea
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• v.16 no.1
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• pp.33-47
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• 2003

Various applied-mineralogical characterization including measurements of surface area, size distribution, swelling index, and viscosity were done for some domestic bentonites in order to decipher the rheological properties and their controlling factors. The bentonites, which are Ca-type and relatively low-grade (rnontmorillonite contents: 30 ∼ 75 wt%), occur mostly as subhedral lamellas with the size range of 2 ∼ 4 $\mu\textrm{m}$. The size distribution of mineral fractions in bentonite suspension is dominant in the range of 10 ∼ 100 $\mu\textrm{m}$, and though rather complicated, exhibits roughly bimodal patterns. The feature is more conspicuous in the case of zeolitic bentonite. The bentonites have surface areas ranging 269 ∼ 735 $\m^2$/g, which are measured by EGME adsorption method. The EGME surface areas are nearly proportional to the rnontmorillonite contents, moisture contents, or total CEC. In the surface area measurements, zeolitic bentonites have slightly higher values than those zeolite- free types. The measured swelling index and viscosity of domestic bentonites are comparatively low in values. The swelling values of bentonites were measured to be 250∼500% at maximum by progressively mixing amounts of 2 ∼ 5 wt% Na$_2$CO$_3$, which varies depending on the contents of rnontmorillonite and other impurities, especially zeolite. Much amount of sodium carbonate is required for optimum swelling property of zeolitic bentonited which has usually strong Na- exchanged capacity. The bentonites, which are comparatively feldspar-rich and low in size and crystallinity, tend to be higher in viscosity values. Tn addition, the viscosity is largely higher in case of the bentonites with higher pH in suspension. However, the rheological properties of bentonites such as swelling index and viscosity do not show any obvious relationships with rnontmorillonite contents and mean particle size in suspension. In contrast, roughly speaking, the swelling index of bentonites is reversely proportional to the values of surface area which can be regarded as a collective physico-chemical parameter encompassing all the effects caused by mineral composition, surface charge, particle size, morphological farm, and etc. in bentonites. Thus, the rheological properties in bentonite suspension appear to be rather complicated characteristics which mainly depend on the flocculation of clay particles and the mode of particle association, i.e. quasicrystals, controlled by surface charge, morphology, size, and texture of rnon-tmorillonite, and which partly affected by the finer impurities such as zeolite.

• Geomechanics and Engineering
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• v.31 no.3
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• pp.305-318
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• 2022

Permeable reactive barriers used for groundwater treatment require proper estimation of the reactive material behavior regarding the emplacement method. This study evaluates the dry emplacement of zeolite (clinoptilolite) to be used as a reactive material in the barrier by carrying out several geotechnical laboratory tests. Dry zeolite samples, exhibited higher wetting-induced compression strains at the higher vertical stresses, up to 12% at 400 kN/m². The swelling potential was observed to be limited with a 3.5 swell index and less than 1% free swelling strain. Direct shear tests revealed that inundation reduces the shear strength of a dry zeolite column by a maximum of 10%. Falling head permeability tests indicate decreasing permeability values with increasing the vertical effective stress. Regarding self-loading and inundation, the porosity along the zeolite column was calculated using a proposed 1D numerical model to predict the permeability with depth considering the laboratory tests. The calculated discharge efficiency was significantly decreased with depth and less than 2% relative to the top for barrier depths deeper than 20 m. Finally, the importance of directional dependence in the permeability of the zeolite medium for calibrating 2D finite element flow analysis was highlighted by bench-scale tests performed under 2D flow conditions.

• Geomechanics and Engineering
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• v.12 no.3
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• pp.523-539
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• 2017

Clay soils are typical for their swelling properties upon absorption of water during rains and development of cracks during summer time owing to the profile desorption of water through the inter-connected soil pores by water vapour diffusion leading to evaporation. This type of unstable soil phenomenon by and large poses a serious threat to the strength and stability of structures when rest on such type of soils. Even as lime and cement are extensively used for stabilization of clay soils it has become imperative to find relatively cheaper alternative materials to bring out the desired properties within the clay soil domain. In the present era of catastrophic environmental degradation as a side effect to modernized manufacturing processes, industrialization and urbanization the creative idea would be treating the waste products in a beneficial way for reuse and recycling. Bottom ash and ecosand are construed as a waste product from cement industry. An optimal combination of bottom ash-eco sand can be thought of as a viable alternative to stabilize the clay soils by means of an effective dispersion dynamics associated with the inter connected network of pore spaces. A CATIA model was created and imported to ANSYS Fluent to study the dispersion dynamics. Ion migration from the bottom ash-ecosand pile was facilitated through natural formation of cracks in clay soil subjected to atmospheric conditions. Treated samples collected at different curing days from inner and outer zones at different depths were tested for, plasticity index, Unconfined Compressive Strength (UCS), free swell index, water content, Cation Exchange Capacity (CEC), pH and ion concentration to show the effectiveness of the method in improving the clay soil.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.394-403
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• 1995

Various thermal treatments such as toasting, roasting, drum drying, autoclaving+drum drying, microwaving+drum drying and extrusion were attempted to investigate their effects on chemical composition (proximate composition, Klason lignin, neutral sugar, uronic acid, starch, free sugar, dietary fiber, phytic acid, etc) and functional properties (water solubility index, water absorption index, water holding capacity, oil holding capacity, bulk density, swelling, etc) of wheat bran. Thermal treatments on wheat bran increased soluble dietary fiber (SDF) content from 2.7% (raw sample) to 4.6% (toasted), 4.5% (roasted), 4.6% (drum dried), 5.2% (autoclaved), 3.7% (microwaved), 5.6% (extruded). In contrast, total dietary fiber (TDF) content remained nearly constant regardless of thermal treatments, reflecting the concomitant decrease in insoluble dietary fiber (IDF). It was also found that water holding capacity (WHC) increased $20{\sim}75%$ due to thermal treatments employed in this research. Both bulk density and swelling were not directly relevant to WHC, but thier multiplication exhibited good correlation $(R^2=0.94)$ with WHC. Scanning elctron microscopy (SEM) exhibited that structure of raw wheat bran was significantly modified, whose degree and shape well reflected the types of thermal treatments.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.4
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• pp.333-342
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• 2001

Adriamycin is a commonly used chemotherapeutic agent for cancer, including acute leukemia, lymphoma, and a number of solid human tumors. However, recent studies have recognized severe cardiotoxicity after an acute dose, which are likely the result of generation of free radicals and lipid peroxidation. Therefore, the clinical uses of adriamycin have been limited. Melatonin, the pineal gland hormone known for its ability to modulate circardian rhythm, has recently been studied in its several functions, including cancer growth inhibition, stimulating the immune system, and acting as an antioxidant and radical scavenging effects. In the present study, we evaluated the effect of melatonin administration on adriamycin-induced cardiotoxicity in rat. Heart slices were prepared using a Stadie-Riggs microtome for the measurement of malondialdehyde (MDA) content used as an index of lipid peroxidation and lactate dehydrogenase (LDH) release as an indicator of lethal cell injury. Serious adriamycin-induced lethality was observed in rat by a single intraperitoneal injection in a dose-dependent manner. A single injection of adriamycin (25 mg/kg, i.p.) induced a lethality rate of 86%, with melatonin (10 mg/kg s.c. for 6 days) treatment reducing the adriamycin-induced lethality rate to 20%. The severe body weight loss caused by adriamycin was also significantly attenuated by melatonin treatment. Treatment of melatonin marked reduced adriamycin-induced the levels of MDA formation and LDH release. A cell damage indicated by the loss of myofibrils, swelling of the mitochondria as well as cytoplasmic vacuolization was seen in adriamycin-treated group. Melatonin attenuated the adriamycin-induced structural alterations. These data provide evidence that melatonin prevents adriamycin-induced cardiotoxicity and might serve as a combination with adriamycin to limit free radical-mediated cardiotoxicity.