• Transactions of Materials Processing
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• v.5 no.2
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• pp.115-121
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• 1996

Recently it is attempted to manufacture gears by various cold forging methods to meet requirements of mass production and uniform qualities. Compared to machined gears cold forged ears reveal higher tooth strength and better surface roughness but they reveal lower geometrical accuracies. Therefore in the present study a series of experiments are performed to investigate relations between geometrical accuracies of dies and billet and those of the final product. The geometrical accuracies of forged gears are considered through functional gear-element tolerances by measuring pitch error profile error lead error radial error tooth thickness and rolling test. Results of the experiments can be summarized as follows: (1) involute spur gears of KS 5(or AGMA7) accuracies can be made,(2) concentricity of die set should be maintained within 0.01mm (3) clearance between the billet and die set should be less than 0.1mm (4) con-centricity and radial runout should be less than 0.08mm and 0.1mm respectively. However it is thought that FEM analysis of elastic/thermal deformations of dies and the billet is necessary for a better understanding of the findings obtained through the present study.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.580-585
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• 2019

In this study, we synthesized amine-functionalized magnesium-phyllosilicates (AF-MgP) with an octahedral and tetrahedral structure using (3-aminopropyl)triethoxysilane. The synthesis of AF-MgP, surface functionalization of amine and 1 : 2 ratio of the octahedral and tetrahedral structure were confirmed by FT-IR and XRD analysis. In addition, it was confirmed that AF-MgP was absorbed evenly on the surface of cotton fibers and coated on the cotton fibers from HR-SEM and EDX analysis. The antimicrobial activity test of cotton fibers according to KS confirmed that cotton fibers coated with AF-MgP particles show an enhanced antimicrobial activity against cutaneous microorganisms. Our results suggest that AF-MgP is not only applied as a functional nanomaterial that gives the cotton fiber antimicrobiality, but also can be used in the field of cosmetic and biomedical materials.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.45-56
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• 2023

This study was conducted to examine the feasibility of preparing a durability evaluation plan in watertightness for sealant applied to a PC structure. To this end, 5 types of sealant that equally satisfy the quality standards of the relevant KS standard were selected and tested. Through this testing, it was found that 3 of the 5 types of sealant showed deterioration in watertightness and durability, such as falling off and cracking from the substrate. For the remaining two types, a visual observation showed no significant changes, but additional analysis, confirmed that there was a large difference in the stress reduction rate of the material. Therefore, based on the above results, the need for a performance review in durability between sealant was confirmed, and based on this, the validity of the durability evaluation plan that can be used in product selection was quantitatively confirmed.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.3
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• pp.276-281
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• 2023

Water pipes manufactured using existing Portland cement suffer from the problem of rapid deterioration and reduced durability due to the hydration product of cement being vulnerable to acids. Therefore, in this study, water pipes were manufactured using slag and fly ash, which are industrial by-products from various industries, and their characteristics were analyzed. As a result of the experiment, slump in unhardened concrete tended to increase due to the ball bearing action of fly ash, and the amount of air was reduced due to unburned coal, indicating that measures for frost resistance were needed. In addition, the initial strength of the compressive strength was increased through steam curing, and the results were equal to or better than OPC when mixing more than 50 % of slag. The acid resistance results showed that the mass reduction rate was less than 5 %, showing excellent durability performance, and the bending failure load of the water pipe also exceeded the KS standards, so it is judged to be commercializable.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.175-179
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• 2023

This paper analyzes the vibration characteristics within the cargo compartment of a three-wheeled cargo bike when used on both regular roads and dedicated bicycle lanes. When cargo is loaded into the cargo compartment of a cargo bike and driven on the road, the shocks and vibrations transmitted from the ground can potentially affect the transported goods and even lead to product damage. As the vibration characteristics applied to the cargo compartment may vary depending on the condition of the road, vibration sensors were attached to the cargo bike's cargo compartment for data collection during operation on different road types. According to KS T ISO 13355 standards, the cargo bike can withstand vibrations within the range of 10 Hz to 60 Hz when operating on both bicycle lanes and regular roads. However, it is observed that there are peaks exceeding the profile in the frequency range of 3-6 Hz. In the 70-200 Hz range, the profile is exceeded on both regular roads and bicycle lanes, with a tendency for higher exceedance on bicycle lanes. The Grms value within the frequency range of KS T ISO 13355 is 5.926 m/s² (0.604 Grms). When operating on bicycle lanes with cargo, the Peak envelope optimization PSD value is 6.553 Grms, while on bicycle lanes, it is 7.708 Grms, indicating a difference of at least tenfold.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.407-422
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• 2014

Objective: The purpose of the study is to develop quantitative usability evaluation criteria for senior-friendly autonomous transportation robot. Background: The Republic of Korea has become the most rapidly aging society, and is anticipated to enter the post-aged society in 2026. To raise the quality of life of a senior with limited mobility and to reduce the burden of caregivers, many high-tech assistive products with information technologies are developed nowadays. The senior-friendly autonomous transportation robot is one person robot vehicle to move a senior to the destination for hospitals, nursing homes or silver town complex. With built-in navigation system and environmental monitoring censors, it automatically seeks the path to the destination and avoids collision to obstacles and pedestrians on the way. Due to the early stage of the product, few usability studies in this field have been done, mostly on general service robots to assist seniors, power wheelchairs and delivery robots. ISO and KS standards for the service robots are focused on safety. Method: Based on the reference usability index, the early draft of the usability evaluation questionnaires was developed. After small group tests and interviews, the experts modified the initial draft to the Usability Evaluation Criteria for Senior-Friendly Autonomous Transportation Robot (UEC-SFATR). Result: UEC-SFATR consisted of 4 subscales - Safety, Controllability, Efficiency and Satisfaction. All of the 4 subscales of UEC-SFATR were passed the reliability criteria by 4 groups of seniors, divided by gender and familiarity of smart-devices. Conclusion: UEC-SFATR covers wider area of user experiences of the SFATR and is a good measurement tool to help both the users and developers of the robot. Application: This study provides guide to the future product development and product competitiveness evaluation by quantifying user experiences for the SFATR.

• The Research Journal of the Costume Culture
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• v.21 no.5
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• pp.708-725
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• 2013

In the 2010s, skinny jeans were trendy, and they became a must-have for young women. The styles, clothing pressure and buying behavior of skinny jeans have been studied, but the patternmaking of skinny jeans has not been researched yet. To analyze skinny jeans patterns, we grouped skinny jeans into nine brands. They were sorted into three groups: special jeans brand, trendy jeans brand, and SPA brand. This study compared skinny jeans' sizing systems, product dimensions and pattern measurements in three brand groups. The appearance and fit of skinny jeans were evaluated by random groups of people in their 20s and 30s. The sizing systems for skinny jeans were different with KS K0051, and they were shown waist girth in inches. The waist and hip circumferences were different among brand groups. In product dimensions, trendy jeans brands had a shorter crotch length, a lower crotch depth, a narrower back crotch width, and a longer inseam than the others. The measurements of skinny jeans flat patterns were significantly different in as below; front crotch depth, front crotch height, front crotch length, back crotch extension, gap between back and front crotch depth, back crotch height, back crotch length, and center back angle. In the sensory survey results, trendy jeans brands were evaluated well in the fit of the waist line, hip line, crotch line, midthigh line, outseam, inseam, side waist line, crotch length and overall fit.

• Korean Journal of Medicinal Crop Science
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• v.16 no.4
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• pp.225-230
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• 2008

Diabetes mellitus is the fifth leading cause of death among Koreans. Control of hyperglycemia and dyslipidemia is strongly correlated with decrease in risks for cardiovascular diseases, the most common and fatal diabetic complication. The effects of chronic feeding of a mixture of Chinese herbs on blood lipid profile were measured in an animal model of type 2 diabetes mellitus, db/db mice (C57BL/Ks). The Chinese herb mixture was composed of Panax ginseng C. A. Meyer,Astragalus membranaceus, Glycyrrhiza uralensis, Lycium chinense, Morus, Pueraria thunbergiana, Prunella vulgaris var. lilacina, Acanthopanax sessiliflorus, Schizandra chinensis, Scutellaria baicalensis, Dioscorea batatas, Polygonatum doratumvar. pluriflorum, Paeonia lactiflora, and Rehmannia glutinosa in a ratio of 1 : 0.7 : 0.4 : 0.7 :0.4 : 0.7 : 1.1 : 0.9 : 0.4 : 0.4 : 0.7 :0.7 : 0.9 : 0.9. Methanol extract of the Chinese herb mixture was tested for the inhibitory activity against yeast ${\alpha}$-glucosidase in vitro. The Chinese herb mixture extract inhibited ${\alpha}$-glucosidase by 25.2% at the concentration of 0.5mg/mL. Four weekold male db/db mice (n = 14) were fed AIN-93G semipurified diet or diet containing 10% powder of the Chinese herb mixture for 6 weeks after 1 week of adaptation period. Body weight (39.5 ${\pm}$ 1.6 g) and food intake (4.3 ${\pm}$ 0.6 g/day) of the Chinese herb group were not significantly different from those of the control group (40.4 ${\pm}$ 2.6 g and 4.5 ${\pm}$ 0.6 g/day). Consumption of Chinese herb mixture significantly decreased plasma glucose level (442.5 ${\pm}$ 36.0mg/dL) compared with the control group (489.8 ${\pm}$ 34.6 mg/dL, p < 0.05). Plasma cholesterol level (159.2 ${\pm}$ 18.4 mg/dL) of the Chinese herb group was significantly lower than that of the control group (185.4 ${\pm}$ 13.7 mg/dL, p < 0.05). Blood glycated hemoglobin (6.3 ${\pm}$ 0.8%) and plasma triglyceride levels (99.4 ${\pm}$ 15.0mg/dL) of the Chinese herb group were not significantly different from those of the control group (6.7 ${\pm}$ 0.7% and 108.8 ${\pm}$ 11.0mg/dL). Thus, the Chinese herb mixture could be useful in the treatment of diabetes and cardiovascular complications of diabetes.

• Fire Science and Engineering
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• v.31 no.6
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• pp.23-32
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• 2017

Foam block, popularized as the self-interior goods, is susceptible to fire since the main material is the polyethylene flammable synthetic resin. However, it is widely used in homes, offices, and multi-use facilities. In order to understand the fire characteristics of the foam block, two kinds of foam blocks sold in the market (non-fire retardant and fire retardant) were evaluated according to standard of KS F 5660-1 (Reaction to fire test). In addition, the hazard analysis of the gas generated by the combustion of the specimen was performed using the FTIR gas analyzer. The cone calorimeter test showed that the ignition and flame combustion of both two specimens were burned as soon as the radiant heat blocking device was removed, and it was confirmed that the flame could become a rapid propagation factor during the fire. The analysis of the combustion gas through the FTIR gas analyzer showed that both the carbon dioxide and carbon monoxide classified as the common combustion gases and the acrolein, ammonia, and hydrogen cyanide causing serious damage to the human body were detected substantially. This study showed that a foam block product has high ignitionability and generates toxic gases. Hence, it is urgently required to establish the standards used for properly classifying the combustion characteristics of the material on the basis of the use conditions of a foam block product and to prepare the standards on the purpose of use.

• Clean Technology
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• v.24 no.2
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• pp.146-153
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• 2018

The water footprint is an important component of the Single Market for Green Product initiative based on the EU's Roadmap to a Resource Efficient Europe. In July 2014, the EU has established the International Standard for Water Footprint (ISO 14046) and Korea has complied with the Korean Industrial Standard (KS I ISO 14046) in April 2015. If a certification system based on the international standard (ISO 14046) is introduced, developing countries such as India and Vietnam, which are not equipped with bases, can become a trade barriers in exporting, so Korea should establish a strategy to reverse them. On the other hand, water footprints are designed to take into account local environmental impacts when compared to similar footprints (eg, carbon footprint) using LCA, so that products manufactured and manufactured in Korea will have an impact on domestic waters Should be considered. Therefore, the method of the water footprint should conform to the standard for compatibility with other countries. In order to consider the domestic water condition, it is necessary to identify suitable indicator or factor for estimating water footprint on Korea. For this purpose, this study analyzed the water footprint estimation study conducted at domestic and foreign based on international standards and through the analysis of statistical data related to domestic water resources, we confirmed the applicability of the water footprint methodology in Korea.