• Journal of the Korean Recycled Construction Resources Institute
• /
• v.9 no.4
• /
• pp.433-442
• /
• 2021

In this study, the properties of no-fines polymer concrete with different polymer binder contents were evaluated. The polymer concrete was formulated using a polymeric binder (unsaturated polyester resin), fly ash, and recycled coarse aggregate (60%) and crushed coarse aggregate (40%). The polymeric binder content (4.0-6.0wt.%) was used as an experimental variable because it dramatically affects both the cost-effectiveness and material properties. The results showed that the density, compressive strength, flexural strength both before and after exposure to freezing and thawing increased as the polymer binder content increased, while the absorption, void ratio, permeable voids, coefficient of permeability, and acid resistance (mass loss by acid attack) decreased as the polymeric binder content increased. In particular, even though the void ratio was 18.4% and the water permeability coefficient was 7.3mm/sec, the compressive strength and flexural strength were as high as 38.0MPa and 10.0MPa, respectively, much more significant than those of previous studies. Other properties such as absorption and acid resistance were also found to be excellent. The results appear to be rooted in the increased adhesion of the binder by adding a cross-linking agent and the surface hydrophobicity of the polymer.

• Journal of the Korean Geosynthetics Society
• /
• v.6 no.3
• /
• pp.9-16
• /
• 2007

Soil vapor extraction (SVE) is an effective and cost efficient method of removing volatile organic compounds (VOCs) and petroleum hydrocarbons from unsaturated soils. Incorporating PVDs in an SVE system can extend the effectiveness of SVE to lower permeability soils by shortening the air flow-paths and ultimately expediting contaminant removal. With this approach, the real bounded system is replaced for the purposes of analysis by an imaginary system of infinite areal extent. The boundary conditions for the contaminant remediation model test include constant head and no flow condition. Due to these parallel boundaries conditions, image wells should be developed in order to maintain the condition of no flow across the impermeable boundary. It is also assumed that the flow is drawdown along the constant head boundary condition. The factors contributing to the difference between the theoretical and measured pressure heads were also analyzed. The flow factor increases as the flow rate is increased. The flow rate is the most important factor that affects the difference between the measured and theoretical pressure heads.

• Biomolecules & Therapeutics
• /
• v.19 no.3
• /
• pp.357-363
• /
• 2011

In relieving local pains, ropivacaine has been widely used. In case of their application such as ointments and creams, it is difficult to expect their effects for a significant period of time, because they are easily removed by wetting, movement and contacting. Therefore, the new formulations that have suitable bioadhesion were needed to enhance local anesthetic effects. The effect of drug concentration and temperature on drug release was studied from the prepared 1.5% Carboxymethyl cellulose (CMC) (150MC) gels using synthetic cellulose membrane at $37{\pm}0.5^{\circ}C$. As the drug concentration and temperature increased, the drug release increased. A linear relationship was observed between the logarithm of the permeability coefficient and the reciprocal temperature. The activation energy of drug permeation was 3.16 kcal/mol for a 1.5% loading dose. To increase the skin permeation of ropivacaine from CMC gel, enhancers such as saturated and unsaturated fatty acids, pyrrolidones, propylene glycol derivatives, glycerides, and non-ionic surfactants were incorporated into the ropivacaine-CMC gels. Among the enhancers used, polyoxyethylene 2-oleyl ether showed the highest enhancing effects. For the efficacy study, the anesthetic action of the formulated ropivacaine gel containing an enhancer and vasoconstrictor was evaluated with the tail-flick analgesimeter. According to the rat tail-flick test, 1.5% drug gels containing polyoxyethylene 2-oleyl ether and tetrahydrozoline showed the best prolonged local analgesic effects. In conclusion, the enhanced local anesthetic gels containing penetration enhancer and vasoconstrictor could be developed using the bioadhesive polymer.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.5
• /
• pp.95-105
• /
• 1996

This study was performed to evaluate the mechanical properties of permeable polymer concrete using fillers and unsaturated polyester resin. The following conclusions were drawn; 1. The unit weight was in the range of 1, 663~ l, 892kg/$cm^3$, the weights of those concrete were decreased 18~28% than that of the normal cement concrete. 2. The highest strength was achieved by fly ash filled permeable polymer concrete, it was increased 22% by compressive strength, 190% by tensile strength and 192% by bending strength than that of the normal cement concrete, respectively. 3. The external strength of permeable pipe was in the range of 3, 083~3, 793kg/m, the external strengths of those concrete were increased 2~26% than that of the normal cement concrete. Accordingly, these permeable polymer concrete pipe can be used to the members and structures which need external strength. 4. The static modulus of elasticity was in the range of $5.7{\times} 10^4 ~ 15.4{\times} 10{^4}kg/cm^2 $, which was approximately 35~64% of that of the normal cement concrete. Fly ash filled permeable polymer concrete was showed relatively higher elastic modulus. The poisson's number of permeable polymer concrete was less than that of the normal cement concrete. 5. The dynamic modulus of elasticity was in the range of $83{\times} 10^3 ~ 211{\times} 10{^3}kg/cm^2 $, which was approximately Ins compared to that of the normal cement concrete. Fly ash filled permeable polymer concrete was showed higher dynamic modulus. The dynamic modulus of elasticity were increased approximately 22~45% than that of the static modulus. 6. The ultrasonic pulse velocity was in the range of 2, 584 ~ 3, 587m/sec, . which was showed about the same compared to that of the normal cement concrete. Fly ash filled permeable polymer concrete was in the range of$0.58~8.88 {\ell}/cm^2/hr$, , and it was larglely dependent upon the mixing ratio. These concrete can be used to the structures which need water permeability.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.5
• /
• pp.109-122
• /
• 1993

ln this paper, a finite element analysis procedure is proposed for the incremental multi-step excavations in a fluid-saturated porous medium such as saturated soil ground. As the basis of derivation, Biot's equation was used. The proposed procedure was applied to some one- and two-dimensional problems under incremental excavations. Unsaturated cases as well as saturated cases were considered for comparison. Through numerical tests, the effects of permeability and excavation speed on the deformation history was investigated. Results showed that pore pressure built up during incremental excavation has a significant effect on the deformation and stresses of solid skeleton and validated the use of the present procedure for the analysis of multi-step excavations in fluid-saturated media such as in saturated shallow ground.

• Journal of the Korean GEO-environmental Society
• /
• v.14 no.5
• /
• pp.41-47
• /
• 2013

Well-graded and dense soils have good engineering properties. Unsaturated soil properties such as shear strength, compressibility and permeability are closely related to the soil-water characteristic curve of the soil. Therefore it is important to study the effects of the coefficient of uniformity and the porosity on the soil-water characteristic curve of the sandy soils, which are also related to the grain size distribution and the density of the soil, respectively. In this study soil-water characteristic curves (SWCCs) for six sandy soil specimens were investigated using Tempe pressure cells. The test data were best-fitted to Fredlund and Xing equation. The obtained fitting parameters and the characteristic points of SWCCs were discussed and correlated with the porosity and the coefficient of uniformity of the specimens. The results show that the smaller the porosity of the specimen becomes, the larger the value of the residual matric suction becomes, whereas the larger the coefficient of uniformity of the specimen becomes, the larger the value of the residual matric suction becomes. Regardless of the coefficient of uniformity, the smaller the porosity of the specimen, the flatter the max. slope of SWCC.

• Journal of Soil and Groundwater Environment
• /
• v.26 no.6
• /
• pp.1-17
• /
• 2021

Self-potential (SP) surveys measure naturally occurring differences in electrical potential in the absence of artificial sources and have been applied to various fields since the first application in mineral explorations. Among various causes of SP occurrences, streaming potential is generated by the flow of groundwater, and makes SP surveys suitable for the exploration of groundwater table fluctuation, fractures, sinkholes and landslide occurrences. Recently, there has been many studies that applied SP surveys to monitor water leakage through dikes and embankments. In this review paper, we first review the characteristics and theoretical backgrounds of streaming potential in saturated or unsaturated porous media to introduce it in the embankment among various application field. After the review of the background theory, we review the past cases of field SP surveys on dikes and embankments and also the characteristics of field streaming potential data in the surveys. Further, by analyzing past studies of qualitative as well as quantitative interpretation of SP survey data, we show the possibility of quantitative interpretation of streaming potential data obtained on dikes and embankments. Consequently, it is hope that this review paper helps researches on SP surveys on dikes and embankments, and provides basis for interpretation methods of the SP data to identify leaked area and further leakage rate (or permeability).

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.21 no.1
• /
• pp.171-180
• /
• 2007

The purpose of this study is to determine the possibility of using Flos Sophora japonica as natural health food source. To accomplish this purpose, the contents of general and antioxidative nutrients of Flos Sophora japonica a were measured. The contents of carbohydrate, crude protein, crude lipid and ash are 67.76%, 19.87%, 4.61% and 7.76%. And the calories of Flos Sophora japonica Linne was 318.32 Kcal. Total dietary fiber was 25.35% of total carbohydrates. The percentages of water soluble dietary fiber to insoluble dietary fiber were 1.80 % and 23.56 %, respectively. The protein were contained total 18 different kinds of amino acids. The contents of non-essential and essential amino acids were 4,898.78mg and 5,953.51mg. The K was the largest mineral followed by Ca, P and Mg, which means Flos Sophora japonica Linne is alkali material. The contents of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids were 29.69%, 34.93% and 35.38%. Therefore, the amount of the total unsaturated fatty acid was higher than that of any other plant. The content of vitamin C in Flos Sophora japonica Linne was higher than that of any other plant, which suggest that it could increase blood elasticity. The content of rutin, which is responsible for capillary vessel permeability, was 22.60%. The contents of water soluble antioxidative materials in 1 mL of water-extracted Flos Sophora japonica Linne were 3.9 ${\mu}$g which is comparable to 1233.0 mmol of vitamin C in antioxidant effect. The general nutrients and other antioxidatant bioactive materials in Flos Sophora japonica Linne were also potential materials for good health food. It is expected that follow up study of Flos Sophora japonica Linne through developing processed food and evaluation of their functional properties would provide useful information as a source of medicinal foods.

• Journal of the Korean GEO-environmental Society
• /
• v.19 no.10
• /
• pp.21-26
• /
• 2018

Soil-water characteristic curve, which is called soil retention curve, is required to explore water flows in unsaturated soils, relative permeability of water in multi-phase fluids flow, and change to stiffness and volume of soils. Thus, the understanding of soil-water characteristic curves of soils help us explore the behavior of soils inclduing fluids. Biopolymers are environmental-friendly materials, which can be completely degraded by microbes and have been believed not to affect the nature. Thus, various biopolymers such as deacetylated power, polyethylene oxide, xanthan gum, alginic acid sodium salt, and polyacrylic acid have been studies for the application to soil remediation, soil improvement, and enhanced oil recovery. PAA (polyacrylic acid) is one of biopolymers, which have shown a great effect in enhanced oil recovery as well as soil remediation because of the improvement of water-flood performance by mobility control. The study on soil-water characteristic curves of sandy soils containing PAA (polyacrylic acid) has been conducted through experimentations and theoretical models. The results show that both capillary entry pressure and residual water saturation dramatically increase according to the increased concentration of PAA (polyacrylic acid). Also, soil-water characteristic curves by theoretical models are quite well consistent with the results by experimental studies. Thus, soil-water characteristic curves of sandy soils containing biopolymers such as PAA (polyacrylic acid) can be estimated using fitting parameters for the theoretical model.

• The Journal of Engineering Geology
• /
• v.14 no.4 s.41
• /
• pp.349-360
• /
• 2004

This study calculated the pore water pressure, the depth of seepage, the constant of the strength in accordance with the slope inclination and the rainfall intensity over the slope built by the weathered granite soil (SP, SM). And, the change of the shear strength in accordance with the rainfall has been compared and analyzed by applying the shear strength formula of the unsaturated soil. As a result, the rainfall intensity is stronger and the slope inclination is gentler the seepage speed in accordance with the rainfall became faster proportionally. As a result of comparing and analyzing both the theoretical value of Lumb and the actual value of the model, it can be said that the actual value is faster. Since SM shows the bigger shear strength than SP, it can also be said that as the granules increase, the coefficient of permeability becomes smaller; and as the seepage rate became smaller, it affects the seepage speed. Likewise, the shear strength within the slope displays the smallest shear strength at the inclination of 1:1.5 the reason of its decrease turned out that it was due to the increase of the pore water pressure.