• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.126-134
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• 1998

In this paper, the field test by truck load and the structural analysis were performed on a prestressed concrete beam bridge to investigate the load carrying capacity of the prestressed concrete beam bridges. From the results of the field test and the structural analysis, CAF (composite action factor), TIF(transformed impact factor), and $P_n$(load carrying capacity) of the prestressed concrete beam bridges were studied, and the load carrying capacity assessment of the prestressed concrete beam bridges were carried out using these factors.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.368-375
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• 1999

This paper describes the evaluation methods and criteria used verify field performance of automatic multi-coupler for the PMC rolling stock. Automatic multi-coupler was designed and manufactured by KRRI , Woojin electric machinery CO., and Yujinchajeon MFG.CO., LTD in 1999. Through field performance test of PMC rolling stock, vibration, brake system, assembly and disassembly of complex train were measured on the condition of service operation. As a result, test results meet the criteria proposed by KNR and KRRI.

• Wind and Structures
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• v.13 no.1
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• pp.21-36
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• 2010

A new full scale testing apparatus generically named the Wall of Wind (WoW) has been built by the researchers at the International Hurricane Research Center (IHRC) at Florida International University (FIU). WoW is capable of testing single story building models subjected up to category 3 hurricane wind speeds. Depending on the relative model and WoW wind field sizes, testing may entail blockage issues. In addition, the proximity of the test building to the wind simulator may also affect the aerodynamic data. This study focuses on the Computational Fluid Dynamics (CFD) assessment of the effects on the quality of the aerodynamic data of (i) blockage due to model buildings of various sizes and (ii) wind simulator proximity for various distances between the wind simulator and the test building. The test buildings were assumed to have simple parallelepiped shapes. The computer simulations were performed under both finite WoW wind-field conditions and in an extended Atmospheric Boundary Layer (ABL) wind flow. Mean pressure coefficients for the roof and the windward and leeward walls served as measures of the blockage and wind simulator proximity effects. The study uses the commercial software FLUENT with Reynolds Averaged Navier Stokes equations and a Renormalization Group (RNG) k-${\varepsilon}$ turbulence model. The results indicated that for larger size test specimens (i.e. for cases where the height of test specimen is larger than one third of the wind field height) blockage correction may become necessary. The test specimen should also be placed at a distance greater than twice the height of the test specimen from the fans to reduce proximity effect.

• Journal of the Korean Geosynthetics Society
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• v.7 no.4
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• pp.47-55
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• 2008

The model test and field test for an infiltration trench were carried out to estimate the infiltration quantity in a granular ground with high permeability like Jeju's ground. The specific infiltration equation was suggested on the basis of the model test result. It shows that the infiltration quantity by the proposed equation is larger than about two times of that by the existed equation. Meanwhile, the infiltration quantity from field test is similar to that from the proposed equation as the result of comparison between infiltration quantity of the filed test and that of the proposed equation and the existed equation. Therefore, it may be right that the proposed equation is applied to estimate the infiltration quantity of the infiltration trench in a granular ground with high permeability.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.794-800
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• 2004

The purpose of this study is to propose a method of controlling freshwater algae which grows abundantly and forms water bloom in the eutrophic water body with $H_2O_2$. Both laboratory and field methodologies were used. For the laboratory test $H_2O_2$ was injected into the different growth phases of incubated Microcystis aeruginosa and the resulting algae growth control rate was examined. For the field test, $H_2O_2$ was dispersed into a lake. Lake water quality was evaluated using a pre-test and post-test analysis of chlorophyll-a, luminance, transmittance, etc., which allowed a comparative evaluation of water quality change. From the experimental results, the growth of algae can be controlled with the small amount of 1mg/L of $H_2O_2$ at the lag phase of growth. The field test results show that the green colour of lake water was removed completely by the reduction of chlorophyll-a and improved transmittance, luminance, TKN, TP, TOC and SS. These indicators of water quality were improved significantly after $H_2O_2$ injection. Toxicity test results using the lake fish show no evidence of detrimental effect of $H_2O_2$ up to 15mg/L. The results of $EC_{50}$ with P. phosphoreum show that the toxicity of $H_2O_2$ was negligible compared to copper which was commonly used for algae control.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.450-457
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• 2020

In this study, engineering characteristics such as flowability, segregation and compressive strength by age to derive fast hardening material mixing proportion using excavated soil. And based on optimal mixing proportion, field simulation experiment conducted in laboratory to examine the effectiveness of the method such as kelly ball drop test and soil penetration test for reviewing the following process. As as a result of evaluation, in case of kelly ball drop test and soil penetration test were securing the following process initiation time 3 hours after place CLSM. As results of these assessments, kelly ball drop test and soil penetration test were applicable for revewing following process in construction field besides unconfined compressive strength method.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.47-52
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• 2009

A sand replacement method is commonly used to determine the density of the compacted soils. The density of the test or compacted soil is computed on the assumption that the calibration container has approximately the same size or volume and allows the sand to deposit approximately in the same way as a test hole in the field. The sand filling process is simulated in the laboratory and its effect on the determination of density is investigated. Artificially-made holes with different heights and bottom shapes are prepared to simulate various shapes of the test hole in the field. Three sands with different gradations are used in the testing to examine how sand grain size influences the determination of density in the field. As the height of a test hole increases, the error between known density and calculated density decreases, regardless of the types of test hole and sand used. The results of this study can be used to reevaluate and revise the test method for soil density by the sand replacement method.

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.1-11
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• 2017

This article reviews the recent activities of field testing and application of superconducting fault current limiters (SFCL) based on high-temperature superconductors (HTS). The review particularly focuses on the trends in the field tests in terms of the technical aspects and commercial activities of the SFCLs. Stimulated by the discovery of HTS, numerous research and development activities have been conducted worldwide for SFCLs operating from distribution voltages to transmission voltages. Different types of SFCLs have been developed and field-tested. Consequently, more than 20 field tests and applications have been performed on real grids worldwide while supplying electric power to the customers. These field tests have not only provided the track records of the operation experiences including the problems and maintenance during operation, but also proved their current limiting capabilities against real faults, rendering this new technology highly viable. Through these activities, the following trends in the status of field testing and application are observed. Resistive-type SFCLs with HTS-coated conductors were dominantly used in the most recent field tests. This implies that the resistive type is technically more mature than the other types. Bus-bar coupling and transformer feeders were the major application locations. It is of importance that most of the field applications were conducted as R&D projects. A relevant change from the R&D stage to the application stage is shown as recently deployed SFCLs are expected to be under long-term operation and commercial service. Here, we review the installation of these SFCLs by substation. This review also discusses the recent activities for their commercial applications.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.865-873
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• 2021

The purpose of this study is to suggest an improvement plan for the practical evaluation method used to determine the national technical qualification in field of flower design to improve its development. First, an advisory committee was formed, after which comparisons, an analyses and matching were conducted of the currently used national technical qualifications and competency units and the competency unit elements of the National Competency Standards in an effort to strength practical skills and industrial field abilities in the field of flower design. Second, we visited an industrial site to understand the practical and technical aspects as well as the facilities and equipment used in the flower design field. The status of workers in the industrial field in the field of flower design was then analyzed. Through this process, practical examination questions were developed for improve the evaluation method. In addition, to ensure a properly configured result, a pilot test was conducted involving those majoring in the field of flower design. To investigate the feasibility of the developed exam, a survey focusing on targets related to flower design was conducted. Based on the results, by suggesting an improvement plan for the practical evaluation method of national technical qualifications in the field of flower design, it is possible to improve knowledge, technical aspects, and literacy, allowing us to train outstanding technical professionals. In the end, this study can be expected to contribute to the improvement of the flower design industry.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.726-739
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• 2009

Objectives : The purpose of this study is to identify differences in time, frequency, and methods of toothbrushing according to knowledge acquirement of oral health between first and third year dental hygiene students who had relatively sufficient oral health education and students majoring non-health related field who had less opportunities of oral health education, to emphasize importance and necessity of the education, and to present basic data for development of effective programs of oral health education. Methods : 2,032 dental hygiene students and students majoring non-health related field attending 12 universities in Korea had been selected as subjects and were asked to complete a self-administered survey time, frequency, and methods of toothbrushing. The SPSS 12.0 program was used for statistical analysis of the collected data, and the significance of difference by groups was tested by using chi-square test, the one-way ANOVA and independent t-test. The mean frequency of toothbrushing per day and the rate of toothbrushing before and after meal were analyzed by using of multiple comparisons through the Scheffe test as post hoc test. Results : The rate of toothbrushing after lunch was 60.2% in third year and 39.2% in first year dental hygiene students, 20.3% in students majoring non-health related field, respectively. The mean frequencies per day of dental hygiene students were 3.33 times in third year and 2.85 times in first year dental hygiene students, 2.46 times in students majoring non-health related field, respectively. The rate of toothbrushing after meal among total frequency of toothbrushing per day was 85.36% in third year and 84.81% in first year dental hygiene students, 77.90% in students majoring non-health related field, respectively. As for the methods of toothbrushing, 'Turning up and down' was 68.8% in third year and 43.1% in first year dental hygiene students, 30.6% in students majoring non-health related field, respectively. Conclusions : Oral health education through dental hygiene course may improve the oral environment management of dental hygiene students and oral health education on toothbrushing should be strengthened for the students majoring non-health related field.