• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.63-70
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• 2014

Part of SB latex in pre-coating color was substituted with newly developed starch-based bio-binder in order to investigate the effect of starch-based bio-binder in pre-coating color on the properties of coating color and coated paper. Smoothness and gloss of coated paper were decreased with the increase of bio-binder substitution ratio. Brightness and whiteness did not show the significant changes, but stiffness was improved with bio-binder. Ink set-off, dry-pick and wet pick were decreased with the increase of bio-binder substitution ratio. In general, when all SB latex is substituted with bio-binder, ink set-off, dry- and wet-pick were deteriorated. However, it was found that if the bio-binder substitution ratio is controlled below 50%, similar qualities with coated paper manufactured by the use of SB latex binder can be obtained.

• Geomechanics and Engineering
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• v.31 no.4
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• pp.409-422
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• 2022

The use of calcium sulfoaluminate (CSA) cement as a rapid-hardening cement admixture or eco-friendly alternate for ordinary Portland cement (OPC) has been attempted over the years, but the cost of CSA cement and availability of suitable aluminium resource prevent its wide practical application. To propose an effective ground improvement design in sandy soil, this study aims at blending a certain percentage of CSA with OPC to find an optimum blend that would have fast-setting behavior with a lower carbon footprint than OPC without compromising the mechanical properties of the cemented sand. Compared to the 100% CSA case, initial speed of strength development of blended cement is relatively low as it is mixed with OPC. It is found that 80% OPC and 20% CSA blend has low initial strength but eventually produces equivalent ultimate strength (28 days curing) to that of CSA treated sand. The specific OPC-CSA blend (80:20) exhibits significantly higher strength gain than using pure OPC, thus allowing effective geotechnical designs for sustainable and controlled ground improvement. Further parametric studies were conducted for the blended cement under various curing conditions, cement contents, and curing times. Wet-cured cement treated sand had 33% lower strength than that of dry-cured samples, while the stiffness of wet-cured samples was 25% lower than that of dry-cured samples.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.3 s.151
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• pp.481-486
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• 2006

There are attempts to utilize Hanji for apparel material, but, the reason that the strength and durability of Hanji decrease to a great extent in the wet condition, restricts the usability of Hanji. In order to improve the resistance against water, Hanji was treated with silicone type water repellent agents. The treatment was carried out by conventional pad-dry-cure method. The optimum treatment condition was obtained by varying the concentration of repellent agent, curing temperature and time. Water repellency was tested by spray rating method. Wet and dry tensile strength, tearing resistance and abrasion resistance were examined after the treatment. Flexural stiffness and wrinkle recovery angles of hanji were also measured. In result, the optimum condition of treatment was at resin concentration of 40g/l, catalyst concentration of 20g/l(half of resin concentration), curing temperature of 160$^{circ}C$, curing time of 120 sec. Flexural stiffness of Hanji was hardly increased and wrinkle recovery angle of Hanji was improved a little by resin treatment. After the treatment, in dry condition, tensile strength and tearing resistance were little changed but abrasion resistance was improved. In wet condition, tensile strength, tearing strength and abrasion resistance were improved.

• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.299-304
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• 2015

This study was conducted to investigate growth characteristics to develop the technique to select resistant cultivar by wet injury at an early stage through the automatic irrigation maintaining 30, 20, 10 kPa respectively using native variety, Chunpoong, Yunpoong, Gumpoong and Sunun. The aerial growth was decreased at 10 kPa compared to 30 kPa. In addition, the survival rate was decreased by 66.6%, 62.3%, 33.8% at 30, 20, 10 kPa, respectively. The survival rate of Chunpoong and Gumpoong were higher than others at 10 kPa. While root growth characteristics such as root length, root weight, number of lateral root and side root were tended to decrease, root diam was no significant or increased. And the more humid condition is, the more the incidence rate of rusty root and rough skin were tended to increase. The epidermal thickness of Chunpoong and Gumpoong was increased but the figures of native variety, Yunpoong and Sunun were decreased at 10 kPa compared to 30 kPa. But, the tissue stiffness of root was decreased at 10 kPa compared to 30 kPa.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.735-749
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• 2008

For the development of the original technique of structural safety assessment of Cargo Containment System(CCS) in membrane type LNG carriers, it is necessary to understand the characteristics of dynamic response behavior of CCS structure under sloshing impact pressure. In the previous study, the wet drop impact response analyses of CCS structure in membrane Mark III type LNG carriers were carried out by using Fluid-Structure Interaction(FSI) analysis technique of LS-DYNA code, and were also validated through a series of wet drop experiments for the enhancement of more accurate shock response analysis technique. In this study, the characteristics of structural shock response behaviors of CCS structure were sufficiently figured out by careful examinations of the effects of specimen weight, drop height, incident angle, corrugation and stiffness of inner hull on its shock response behaviors. The shock response analysis of upward shooting fluid to inner hull was performed, and the reason of faster strain response than shock pressure one was also figured out.

• Steel and Composite Structures
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• v.32 no.1
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• pp.127-139
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• 2019

Bridges, offshore oil platforms and other infrastructures usually require at some point in their service life rehabilitation for reasons such as aging and corrosion. This study explores the application of adhesively bonded CFRP patches in repair of corroded circular hollow sectional (CHS) steel beams. An experimental program involving three-point bending tests was conducted on intact, corroded, and repaired CHS beams. Meso-scale finite element (FE) models of the tested beams were developed and validated by the experimental results. A parametric study using the validated FE models was performed to examine the effects of different CFRP patch parameters, including patch dimensions, number of plies and stacking sequence, on efficiency of the repair system. Results indicates that the corrosion reduced elastic stiffness and flexural strength of the undamaged beam by 8.9 and 15.1%, respectively, and composite repair recovered 10.7 and 18.9% of those, respectively, compared to undamaged beam. These findings demonstrated the ability of CFRP patch repair to restore full bending capacity of the corroded CHS steel beam. The parametric study revealed that strength and stiffness of the repaired CHS beam can be enhanced by changing the fiber orientations of wet composite patch without increasing the quantity of repair materials.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.1
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• pp.17-23
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• 2009

The influence of different forming elements on the local paper structure and the related paper properties was investigated in this study. Specifically, a conventional papermaking foil system and a velocity induced drainage (VID) system were compared. The study involved the analysis of the product samples obtained from the commercial machine trials. The paper samples produced with VID forming systems showed better formation. The deterministic patter in the local structural profile map of the Foil samples indicated the structure of foil samples was more supple after forming process and then easier to be marked by various fabrics such as wet pressing fabric. The higher bulk was observed in the VID samples, which resulted in higher scattering coefficient, lower ZDT strength, and higher bending stiffness.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2003.05a
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• pp.8-13
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• 2003

Frictional sound of 13 vapor permeable water repellent fabric by sound generator were recorded and analysed through FFT analysis. The frictional Sounds were quantified by calculating total sound pressure(LPT), the level range ΔL and the frequency difference Δf. Mechanical properties were measured by KES-FB. LPT values of specimens finished wet coating were higher than those of dry coating. Values for bending rigidity, shear stiffness, surface roughness and compressional recovery of polyurethane fabrics increased compared with the cire finished fabrics. Laminated fabrics had high values of frictional coefficient and low values of surface roughness. LPT showed significant correlation with compressional energy, weight and thickness. (ΔL) was highly correlated with compressional linearity, frictional coefficient, compressional recovery, and (Δf) with tensile linearity, compressional energy, thickness, and weight.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.3
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• pp.144-151
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• 2003

IPMC(Ionic Polymer-Metal Composite) is promising candidate material for bio-related actuators mainly due to its biocompatibility and wet and soft properties. The widely used commercialized Nafion film has a few kinds of fixed thicknesses but more various film thicknesses are required for extensive applications. Especially for the enhanced force as an actuator, the thick film is essential. Various Nafion films with thickness of 0.4-1.2mm have been prepared by casting of liquid Nafion. Also, IPMC actuators using casted Nafion films have been fabricated and the basic mechanical properties such as stiffness, displacement and force were measured and analyzed. These results can be used for the optimized design of actuators for different applications.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.804-806
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• 1998

In this study, piezoelectric composites with 1-3-0 connectivity have been studied. A Piezoelectric ceramic PZT Prepared by Wet-Dry Combination method is used as a filler in mixture of Eccogel polymer matrix and third Phase. The density and stiffness of 1-3-0 type composites were decreased with increasing the third phase.