• Science of Emotion and Sensibility
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• v.13 no.2
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• pp.391-402
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• 2010

In this study, breathable waterproof materials were prepared by electrospinning. Five kinds of electrospun nanofiber web layered systems with different levels of nanofiber web density, as well as different substrates and layer structures were fabricated, and their mechanical properties (tensile, bending, shear, compression, surface, and thickness & weight) were measured by the KES-FB system and compared with those of conventional breathable waterproof fabrics (densely woven fabric, PTFE laminated fabric and PU coated fabric). The KES-FB measurements demonstrate that the lab-scale nanofiber web layered systems are more flexible and fuller than commercial nanofiber web layered systems, which have a more compact structure than the lab-scale nanofiber web layered systems. Densely woven fabrics and lab-scale nanofiber web layered systems showed lower values of tensile linearity (LT), bending stiffness (B), and shear stiffness (G) than those of PU coated and PTFE laminated fabric. These results indicate that they are more flexible and have less resistance to the shearing movement, corresponding to a more pliable material having a better drape, than PU coated fabrics and PTFE laminated fabrics.

• Journal of the Korean Society of Food Culture
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• v.13 no.3
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• pp.191-196
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• 1998

The influence of organic acid dips on the quality properties, color, cooking quality, textural and sensory properties, and reducing microbial population of LL(Long Life) noodles was studied. The contents of organic acid used were 0.2% based on flour weight and LL noodles were treated by dipping in pH $2.5{\pm}0.1$ for $60{\sim}90sec$. The whiteness of LL noodles treated with dl-malic acid was higher than that of others. The shear extrusion force and hardness of LL noodles treated with dl-malic acid were shown much higher value than those of others except treated with dl-malic acid. acetic acid(=1:1). At cooking quality examination of LL noodles treated with organic acids, weight of cooked LL noodles treated with dl-malic acid was decrease but volume was appeared in vice versa. Extraction amounts of LL noodles treated with dl-malic acid, dl-malic acid : acetic acid(=1:1) during cooking were much smaller than those of others. Total counts of microorganism of LL noodles treated with dl-malic acid,dl-malic acid. acetic acid(=1:1) were disappeared during storage at $30^{\circ}C$ but treated with latic acid, acetic acid were increase during storage. Sensory properties of cooked LL noodles which was treated with dl-malic acid showed quite acceptable.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.1 s.53
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• pp.1-9
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• 2007

The purpose of this study is to carry out the quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of CFRD(Concrete-Faced Rockfill Dam) subjected to earthquake loading. The total 105 dynamic numerical analyses (2 input earthquake, 2 magnitudes for each earthquake. 27 rockfill material property combinations obtained from large triaxial tests) on CFR type "D" dam in operation were conducted. The global sensitivity analysis was carried out using the results of numerical analysis. From the results of sensitivity analysis, It was found that the crest settlement of the CFR type dam subjected to earthquake was absolutely affected by the shear modulus of rockfill material irrespective of the input earthquakes and the maximum acceleration of each earthquake. Also, it was found that the horizontal displacement of the dam crest was highly affected by the shear modulus of rockfill material though the extent of effect on that was smaller than the settlement and the extent of effect depended on the input earthquakes and the maximum acceleration of each earthquake. On the contrary, it was found that the effect of friction angle was negligible.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.152-159
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• 2014

KRISO(Korea Research Institute of Ships & Ocean Engineering) designed and manufactured a pilot mining robot called "MineRo" in 2012. MineRo is composed of four track modules. In general, much time and money are needed for deep-sea tests. Therefore, a numerical analysis to predict the dynamic behaviors has to be performed before a deep-sea test. In the numerical analysis, the information about the mining robot and soil properties are the most important factors to analyze the driving performance and dynamic response of MineRo. A terra-mechanics model of extremely cohesive soft soil is implemented in the form of the relationships between the normal pressure and sinkage, and between the shear stress and shear displacement. It is possible to acquire information about MineRo from the CAD model in the design phase. The Wong model is applied to the terra-mechanics model. This model is necessary to acquire many soil coefficients for a numerical analysis. However, in soil testing, the amount of soil property data obtained is limited. Moreover, it is difficult to analyze all of the cases for the many soil coefficients. In this paper, the dynamic behaviors of MineRo are analyzed according to the driving velocity, steering ratio, and variable extremely cohesive soft soil properties using a table of orthogonal arrays. The dynamic responses of MineRo are the turning radius, sinkage, and slip ratio. The relationships between the dynamic responses and variable soil properties are derived for MineRo.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.421-431
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• 2007

The main purpose of this study is to develop a sprayed FRP repair and strengthening method, which is a new technique for strengthening the existing concrete structures by mixing one of the carbon or glass chopped fibers and one of the epoxy or vinyl ester resins with high-speed compressed air in open air and randomly spraying the mixture onto the concrete surface. At present, the sprayed FRP repair and strengthening method using the epoxy resin has not been fully discussed. In order to investigate the material property of the sprayed FRP, this study carried out tensile tests of the material specimens, which were changed with the combinations of various variables including the length of chopped fiber and the mixture ratio of chopped fiber and resin. These variables were set to have the equal material strength, compared with that of one layer of the FRP sheet. As a result, the optimal length of glass and carbon chopped fibers was fumed out to be 38 mm, and the optimal mixture ratio between chopped fiber and resin was also turned out to be 1 : 2 from each variable. And also, the thickness of the sprayed FRP to have the equal strength to one layer of the FRP sheet was finally calculated. In is study, a series of experiments were carried out to evaluate the strengthening effects of flexural beams, shear beams and damaged beams strengthened with the sprayed FRP method, respectively. The results revealed that the strengthening effects of the flexural and shear specimens were reasonably similar to those of the FRP sheet, and the developed Sprayed FRP technique is able to be used as a strengthening scheme of existing RC building.

• Korean Journal of Food Science and Technology
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• v.39 no.6
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• pp.608-613
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• 2007

This study was conducted to evaluate the meat quality of pork produced by feeding fermented rice bran (FRB) (10 to 20%). In the proximate composition analysis there were no significant differences, but the FRB treated groups showed a tendency for higher moisture content and a lower fat content. There were no significant changes found in the physicochemical property analysis, except for cooking loss and water holding capacity, which are the most important factors for estimating meat quality. The cooking loss of the FRB pork was significantly lower than that of the control group (p<0.01). The water holding capacity of the 20% FRB roup was higher than that of the control group (p<0.01). The shear force value of the 20% FRB group was also higher than that of the control group, but the 10% FRB group showed no difference from the control group. The total free amino acid volume of the meat increased, depending on the volume of FRB added. The contents of glutamic acid, glycine, and alanine, which are important factors for taste and flavor, were higher in the FRB groups an the control group. In the sensory analysis, the FRB groups showed high scores for color, aroma, flavor, juiciness, taste, and overall acceptability. Taken together, adding FRB to the feed improved the quality of pork.

• The Journal of Engineering Geology
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• v.17 no.3
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• pp.455-469
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• 2007

The study area, Bonggil-ri, Gyeongju, SE Korea, is composed of Cretaceous sedimentary rocks, and Tertiary igneous rocks and dykes. A research on fracture developing history and density distribution was carried out on well exposed Tertiary granites. The fractures developed in this area have the following sequence; NW-SE trending duo-tile shear bands (set a), NNW-SSE trending extensional fractures (set d), WNW-ESE trending extensional or normal fractures (set b), NE-SW trending right-lateral fractures (set c), WNW-ESE trending reverse fault reactivated from normal faults (set e) and NW-SE trending left-lateral faults reactivated from shear bands (set a) under brittle condition. According to the result of fracture density analysis, the fracture density in this area depends on rock property rather than rock age, and also higher fracture density is observed around fault damage zones. However, this high fracture density may also be related to the cooling process associated with dyke intrusion as well as rock types and fault movement. Regardless of the reason of the high fracture density, high fracture density itself contributes to fluid flow and migration of chemical elements.

• Journal of Adhesion and Interface
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• v.11 no.2
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• pp.41-49
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• 2010

Furan-containing epoxide monomers (8, 9) were designed and synthesized as carbon-neutral, environment-friendly adhesion material. Bicyclic skeleton were constructed using the Diels-Alder reaction of furan and methyl acrylate, both readily accessible starting material from a biomass via bio-refinery process. After reduction of ester functionality, resulting hydroxyl moieties were coupled to epichlorohydrin to provide the epoxy-functionalized furanic monomers (8, 9). The structure of new furanic monomers was confirmed by $^1H$ and $^{13}C$ NMR spectroscopy. As UV-curable monomers, basic properties such as UV curing time and the extent of UV curing were evaluated by photo DSC. Photo-curing shrinkages were measured by linear variable differential transformer transducer (LVDT) and the effect of molecular structure on shrinkage was considered. In addition, new synthetic compounds showed the shear strength over 3 MPa when they were photo-cured between polycarbonate plates, which indicates these compounds are feasible to use as photo-curable adhesive materials.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.85-92
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• 2008

Strength of logs and round posts is compared and analyzed to estimate the strength of the incised Larix round posts treated with CCA in this paper. There is no significant difference in MOR of logs and round posts. However, in the incised Larix round posts treated with CCA MOE is decreased to about 9%, and there is 29% reduction in MOR as strength ratio is 0.71. When calculating the allowable bending stress of incised round type round posts, not in nominal 2-in timbers, an adjustment factor for MOE and bending strength is proposed as 0.91 and 0.71, respectively. Logs, round posts and the incised Larix round posts treated with CCA do not show significant difference in nail withdrawal load. There is almost no difference between incised Larix round posts treated with CCA and round posts in the shear strength of bolted joint. When calculating the allowable shear stress of bolted joint, it is conformed that considering the application of incising factor is not necessary.

• Journal of Adhesion and Interface
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• v.12 no.3
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• pp.99-104
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• 2011

Currently, automotive pre-primed coatings has been developed to overcome environmental regulations and to reduce manufacturing cost in automotive industry. By these reasons, an automotive pre-primed system has been investigated to remove the wash and pre-treatment process using a roll coating application. It is required to develop non-weldable pre-primed system for automotive structural adhesives, because pre-primed sheet coated with organic compounds is hard to be assembled by welding process. Primer 1 (polyester type) and primer 2 (urethane type) were designed to satisfy flexibility and formability for non-weldable pre-primed system. According to the results of physical property test of the primers, adhesion test such as single-lap shear test and T-peel test, primer 1 (polyester type) had better physical properties such as pencil hardness, solvent resistance, flexibility and adhesion with automotive adhesive than that of primer 2 (polyurethane type). In addition, the possibility of the non-weldable pre-primed system was applicable to automotive assembly process in place of welding process.