• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.171-172
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• 2015

Recently, it is the global warming phenomenon because of the greenhouse gas exhaustion caused by and the environment problem is serious. And it is the situation where the problem of the exhaustion of resource because of the indiscriminate picking of the that is the raw material of the cement, limestone and natural aggregate are emphasized. In addition, thus the cement reduction amount of use and substitute material research is the urgent actual condition with the gas emission, which here it is generated in conducting compression molding in the building stone manufacturing process performance degradation phenomenon and fire resistance, and problem of the durability. Therefore, in this research, the waste porcelain is applied to the artificial stone and the durability property of the artificial stone according to it tries to be investigated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.239-244
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• 2011

This study analyzes the behaviors on stress, fatigue and vibration about bulldozer in operation. Maximum equivalent stress is shown with the frequency of 100 Hz in case of the harmonic vibration analysis applied with force. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to -105MPa and the amplitude stress of 0 to $1.617{\times}105MPa$, the possibility of maximum damage becomes 3.23%. This stress state can be shown with 5 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of bulldozer by investigating prevention and durability against its damage.

• Structural Engineering and Mechanics
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• v.69 no.1
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• pp.77-93
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• 2019

Although much research has been carried out using recycled aggregates sourced from normal strength concrete, most of the buildings to be demolished are constructed with low strength concrete. Therefore, the properties of the concrete incorporating recycled aggregates, sourced from the waste of structural elements cast with low strength concrete, were investigated in this study. Four different concrete mixtures were designed incorporating natural and recycled aggregates with and without fly ash. The results of the mechanical and durability tests of the concrete mixtures are presented. Additionally, full-scale one-way reinforced concrete slabs were cast, using these concrete mixtures, and subjected to bending test. The feasibility of using conventional reinforced concrete theory for the slabs made with structural concrete incorporating recycled aggregates was investigated.

• Journal of the Korea Safety Management & Science
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• v.25 no.2
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• pp.153-158
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• 2023

This research was conducted to reduce the defect rate caused by nozzle clogging of printing heads used in binder jet 3D printers. The binder jet 3D printing technology may adhere to the printing head nozzle by dispersing powder due to mechanical operation such as transferring the printing head and supplying powder, and may cause nozzle clogging by natural curing at the nozzle end depending on the type of binder used. To solve this problem, this study created a cleaning module exclusively for printing heads to check whether the durability of printing heads is improved through analysis of printing results before and after using the cleaning module. To this end, this research used a thermal bubble jet printing head, and the used powder was studied using gypsum powder.

• Smart Structures and Systems
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• v.9 no.1
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• pp.1-20
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• 2012

In bridge engineering, maintenance strategies and thus budgetary demands are highly influenced by construction type and quality of design. Nowadays bridge owners and planners tend to include life-cycle cost analyses in their decision processes regarding the overall design trying to optimize structural reliability and durability within financial constraints. Smart permanent and short term monitoring can reduce the associated risk of new design concepts by observing the performance of structural components during prescribed time periods. The objectives of this paper are the discussion and analysis of influence line or influence field approaches in terms of (a) an efficient incorporation of monitoring information in the structural performance assessment, (b) an efficient characterization of performance indicators for the assessment of structures, (c) the ability of optimizing the positions of sensors of a monitoring system, and (d) the ability of checking the robustness of the monitoring systems applied to a structure. The proposed influence line- model correction approach has been applied to an integrative monitoring system that has been installed for the performance assessment of an existing three-span jointless bridge.

• Textile Coloration and Finishing
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• v.24 no.4
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• pp.260-269
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• 2012

The aim of this study was to develop higher-value added dyeing materials with the fermentation-dyeing -mordanting system using only the natural ingredients by integrating traditional fermentation techniques with traditional dyeing technique. Nuruk, which is used mainly to ferment traditional foods, was used as a fermenting agent to ferment 5 different types of materials. Acidic burnt alum and alkaline calcium hydroxide were used as natural mordants. The dyeability checked after fermentation showed that both cotton and silk mordanted with Gardenia jasminoides did not show notable changes, and 10 days of fermentation was found to be appropriate. Sophora japonica L. performed better on cotton materials mordanted with slaked lime, and alkaline mordants were found to be more effective than acidic ones. With Rheum coreanum, a fermentation period of more than 24 days ($5^{th}$ fermentation) worked best on cotton material, showing a 5 fold increase in the K/S value after the $5^{th}$ slaked lime fermentation than with no fermentation. Rhus javanica L. was found to increase the color fastness to gentle washing and the fastness to light was found to possess 4 means that natural dyed fabric have the highest level of durability, the grade 1 the lowest level of fastness.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_2
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• pp.475-480
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• 2021

The purpose of this study is to obtain the natural frequency of fuel supply pipes for vehicle engines through modal analysis and testing and compare the resulting values to ensure the reliability of the analysis. In other words, in this study, we obtain the unique frequency of the fuel pipe of the vehicle engine through analysis and testing and compare its results. Comparing the natural frequency obtained through analysis and testing, the first and third vibration modes obtained accurate natural frequency results of less than 1% and very similar results of less than 5% maximum error over the fourth vibration modes. These results are determined that if design changes of fuel pipes are made depending on the vehicle in the future, there will be no problem in obtaining the natural frequency of pipes that have been changed by analysis. Through future analysis and testing, durability and stability evaluation of connections of fuel supply pipes for vehicle engines will be carried out.

• Journal of the Korean Wood Science and Technology
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• v.41 no.3
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• pp.187-200
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• 2013

Current research trends of non-copper wood preservatives for enhancing durability was reviewed; as a follow-up of the review in 2012 on copper-based wood preservatives. Main environmental friendly non-copper wood preservatives studied by many scientists were boron-based compounds, synthetic compounds from natural products, and pyrethroids family of chemicals, etc. The critical issue regarding treated woods with boron-based compounds used outdoors was the leaching of boron. Many studies mainly focused on boron fixation improvement using variety of polymers. Moreover, the studies showed notable increases in attempts to use natural products used commonly in the medical fields as wood preservatives as well as outdoor use of chemical modified such as acetylated wood developed in purpose of stabilizing dimension.

• The Research Journal of the Costume Culture
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• v.9 no.4
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• pp.629-638
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• 2001

This study was intended to identify the desired image and fabric preference of woman college student for apparel and the relationship between these variables. Data were collected by questionnaire distributed to 260 woman college students through August to September of 2000. After eliminating incomplete questionnaires, 236 were analyzed. The most desired image was neat, and the most preferred fabric was natural fiber textile in fiber contents and light and soft in fabric sensation. The avoided image was masculine, and the negative sensation was heaviness. As a result of factor analysis, 7 factors -cute, intellectual, animate, neat, mature, sporty, sexy- were determined in image. And 8 factors -soft, durable, flat, rigid, light, bulky, heavy, pliable- were determined in fabric sensation. These factors explained large percentage of variance respectively. Multidimensional scaling was employed to analyze the relationship between desired image and fabric preference. Two dimensions were accepted to interpret the relationship. One of the results showed the closeness among the natural fiber textile, lightness, durability and natural image. And the short distance among the blended textile, elasticity, warmness and sporty image was presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.134-139
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• 2003

This study was carried out to investigate the aging and conversion characteristics of oxidation catalysts for a natural gas vehicle with lean-bum system. The conversion of $CH_4$ was observed over the various composition ratio of PMs(Precious metals) and washcoating methods. On the fresh catalysts, Pd affected on the activity of $CH_4$ at low temperature more than other PMs in Pd-only and Rh/Pd/Pt catalysts. The activity at low temperature increased as a mount of Pd increases. On the aged catalysts, the $CH_4$ conversion efficiency of Pd-only catalyst with mono-layer washcoat decreased more than that of the other catalysts of $CH_4$ conversion. It was observed that the thermal durability of Rh/Pd/Pt catalysts with double-layer washcoat was better than the single washcoat catalyst.