• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.5
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• pp.485-496
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• 2020

Submerged structures such as low-crested breakwaters and artificial reefs have been commonly used for coastal protection. In this study, two-dimensional laboratory experiments were conducted in a wave flume to investigate the wave transmission phenomena of permeable type submerged structures armored by Tetrapods. Different cases of the experimental conditions were included by relative crest depth, relative freeboard, relative crest width, wave steepness and so on. An empirical formula from the experimental data was proposed to predict the wave transmission coefficients over various specifications and structural designs of the permeable type submerged structure. The proposed formula successfully predicted the wave transmission coefficients. In this study, the proposed empirical formula of the wave transmission over the submerged structure was improved from the existing formula.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.193-198
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• 2011

This study aimed to provide basic data for permeable pavement application upon design and installation stages by analyzing the effect of permeable pavement used on the facility area rather than using non-point pollutants treatment facility upon development business in accordance with recent trend. To perform this study, the area of development target was separately applied as impermeable and permeable developments so as to compare and analyze the economics of cut pollution load and installation construction cost. Consequently, the processing amount and cut load of non-point pollutant sources are influenced much by permeable and impermeable developments, and it was turned out to be better to develop target river area as permeable area rather than installing non-point pollutants treatment facility of equipment type or natural type upon development to yield smaller discharge load. If we can prepare a countermeasure regulating impermeable area ratio to certain level to manage non-point pollutants upon development based on this result, we can minimize the source of pollution caused by the development.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.2
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• pp.123-140
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• 2009

The effect of a solute concentration difference on the osmotic transport of water through the semi-permeable membrane of a simple cell model is investigated. So far, most studies on osmotic phenomena are described by simple diffusion-type equations ignoring all fluid motion or described by Stokes flow. In our work, as the governing equations, we consider the coupled full Navier-Stokes equations which describe the fluid motion and the full transport equation that takes into account of convection and diffusion effects. A two dimensional finite difference model has been developed to simulate the velocity field, concentration field, and semi-permeable membrane movement. It is shown that the cell swells to regions of lower solute concentration due to the uneven water flux through the semi-permeable membrane. The simulation is applied on a red blood cell geometry and the relevant results are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.130-135
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• 2000

The purpose of this study is to examine the physical properties of water-permeable concretes. The water-permeable concrete with cement-aggregate ratios of 1:3.5 to 1:6.0 and two type of coarse aggregate size of 8~13 and 13~18mm used OPC(ordinary portland cement) as a binder and superplasticizer are prepared, and then tested for flexural strength, compressive strength, compressive strength, continuous void percentage and coefficient of water permeability. It is concluded from the test result that the superior flexural and compressive strengths, coefficient of water permeability and continuous void percentage of water-permeable concretes that use OPC were obtained at cement-aggregate ratios of 1:3.2, 1:6.0 respectively, The water-permeable concretes with coarse aggregate of 8~13 and 13~18mm size used OPC as a binder havinga flexural strength of 24.81~45.56kgf/$\textrm{cm}^2$, 21.99~40.62kgf/$\textrm{cm}^2$, a compressive stength of 93.63~ 242kgf/$\textrm{cm}^2$, 114.8~191.7.kgf/$\textrm{cm}^2$, a coefficient of permeability of 0.59~1.85kgf/$\textrm{cm}^2$, 0.73~ 2.25kgf/$\textrm{cm}^2$, and a continuos void percentage of 16.6~26.32%, 13.52~24.35% respectively during 28 curing days.

• Korean Journal of Human Ecology
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• v.10 no.4
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• pp.333-347
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• 2001

The purpose of this study is to find out the washing methods specified on the care labels of vapor-permeable & water-proofed fabrics and to investigate the consumers' real washing methods in their home and their cognition. In this study, the condition of care labels on 35 products was investigated and consumers' washing methods and cognition were surveyed. The subjects were consisted of majoring clothing textiles' female, female student attending in other major and married-women. Data were analyzed SPSS 10.0. The major results were as follows : 1. The care labels of Vapor-permeable & waterproofed fabric products used in this survey followed the rule of KS K that is stated that care labels must include over 3 instructions. It was the most popular type of care labels to organize with washing methods, bleaching methods, weaving methods, drying methods, ironing methods. 2. Most consumers have vapor-permeable & waterproofed fabric products, but their consciousness of this fabric is low. The rate of consumer confirming the care labels was 76.6% but 67.8% of them answered they take care of textile products with their experiences. 3. Consumers' understanding of care instructions on care labels was investigated that most consumers understand domestic care instruction, but they didn't know almost all international one.

• Journal of The Korean Association For Science Education
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• v.27 no.2
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• pp.144-152
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• 2007

In this study, high school science teachers' and students' various conceptions related to osmosis phenomena were compared with and analyzed in relation to the content of science textbooks used in high school science classrooms and college science courses. The questionnaires developed by the researchers were administered to science teachers and students. Differences can be found between the explanations of science textbooks on osmotic pressure and semi-permeable membranes. Many science teachers and students thought of osmotic pressure as 'membrane pressure occurred by the movement of a solvent'. Moreover, the types of teachers of semi-permeable membranes were similar regardless of their academic majors. Many of the teachers thought of a semi-permeable membrane as a membrane that 'passes small-size particles'; however, many students thought of this type of membrane as being 'selectively permeable'. Also, the salt-pickling cabbage phenomenon seemed to cause significant confusion to science teachers and students. These study results show that teachers and students possess various conceptions related to the osmosis phenomena. These different conceptions related to osmosis phenomena might cause confusion and diverse conceptions including misconceptions among teachers and students.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.1-7
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• 2020

Non-point pollution adversely affects the water system and its influence is increasing. In order to manage such nonpoint source pollution, the government has conducted studies on LID (Low Impact Development) facilities and various efficiency evaluations. In this study, the actual installed permeable block facility among the various LID facilities was analyzed the effluent reduction rate, the residual rainfall analysis, the runoff duration time and the reduction rate of the maximum inflow and outflow for the rainfall runoff control and the results were compared the other facilities. The analysis results show that the reduction efficiency is high in order of impermeable block, filter type permeable block, and clearance type permeable block, and the graph showing the relationship between the rainfall intensity and the runoff duration time is presented. This graph can be helpful in the design of facilities such as the facility capacity selection according to the reproduction period of the permeable block facility similar to this.

• Particle and aerosol research
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• v.10 no.3
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• pp.109-117
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• 2014

In Korea, permeable protection clothes for chemical agent is being developed and distributed. But permeable protection clothes are vulnerable for biological agent of particle type. Therefore selective permeable membranes are being developed to protect chemical agent and biological agent simultaneously. In this study, aerosol collection efficiency test was performed to validate the protection performance of permeable clothes and selective permeable membranes. Aerosol collection efficiency test was performed by using the aerosol test equipment that could test aerosol particle diameter from $0.005{\mu}m$ to $3.0{\mu}m$. This study shows the test method and performance test results for collection efficiency by using the aerosol test equipment.

• Fashion & Textile Research Journal
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• v.23 no.1
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• pp.129-141
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• 2021

This study investigated fabrics, washing and cares, design, pattern, subsidiary materials, and sewing methods with a focus on the functional outers using moisture-permeable waterproof fabric as a shell; in addition, each element was analyzed for differences depending on fabric type. The characteristics of 34 outers were investigated through labels, online product introductions, visual inspection, observations from two experts with more than 30 years experience and wear tests. Moisture-permeable waterproof fabrics used for the outer were classified into two types; in addition, the shell of the high-density fabric and the 2 & 3-layer fabrics had different characteristics. Various fabrics, detailed designs, and three-dimensional patterns suitable for each part of the human body were used to improve functionality. In addition, various subsidiary materials and sewing methods were used to form an organic relationship. The same washing and cares, patterns and subsidiary materials were used regardless of fabric type; however, the fabric type influenced the detailed design and sewing. The outers with high-density fabric had a loose fit, short placket, e-banded cuffs, lock-stitch, and lock-stitch+binding. However, the outer with 2 & 3 layer fabric had a slim fit, hood width adjustment, zippered pockets, cuffs with tab, seamless adhesive sewing such as laminating, lock-stitch+ seam-sealing, and welding.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.149-158
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• 2017

Permeating injection is commonly known as an ideal type of injection in grouting reservoir embankment, yet often-combined permeating and fracturing injection grouting operation can disturb the original soil. A grouting method has been regarded as effective and developed to ameliorate the possible disturbance problem. It involves compaction grouting with low expansive pressure near the injection hole and repetitive injection and compaction with grout material that allows ideal permeating injection. This thesis develops Hybrid Grout (ie. HG grout) that allows various application in any ground condition combined together, has high fineness and low viscosity, and expands permeation injection to silty sand. It researches on the injection effect of permeable compaction grout which is done with PC packer and is a combination of HG grout and expansion agent to obtain permeation compaction effect on the area near grout injection spot by developing Permeable Compaction Type Packer(ie. PC packer). As the developed PC packer, HG grout, and and expansion agent (HI-E) are applied to reservoir embankment reinforcement grouting, possibile permeation compaction effect that satisfies reservoir embankment grouting standard is confirmed according to the research.