• Journal of Korean Society of Steel Construction
• /
• v.29 no.6
• /
• pp.455-465
• /
• 2017

To figure out the weldability and welded joint performance on the FCAW of SM490TMC 120mm, several specimens were manufactured and 10 kinds of experiments were implemented. The result of the weld zone chemical composition test, weld metal tensile test, weld zone tensile test, and weld zone impact test has satisfied the KS. Especially, the weld zone tensile test result shows the base metal fracture, which means the weld zone performs enough required performance. In addition, the results of the weld zone bending test, hardness test, macroscopic test, microscopic test, and the maximum hardness in HAZ were showing that the FCAW weld zone has fine quality.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.28 no.4
• /
• pp.331-340
• /
• 2008

This study was conducted to investigate the effects of the type of swine manure on herbage productivity, the properties of soil and environmental pollution in mixed grassland. The field experiment was carried out on Livestock Breeding Station, Chonbuk in Korea from Nov. 2002 to Nov. 2005. Experimental plots were consisted of the types of swine manure, such as additional swine manure fermented with sawdust (SMFWS)+urea 50% and swine slurry (SS)+urea 50%. And then, chemical fertilizer (Urea) is used as control. DM yields of herbage were not different between chemical fertilizer and the type of swine manure. Feed values (CP, NDF, ADF, TDN) were not different between chemical fertilizer and swine manure treatments. After finishing with the experiment, Organic matter contents in soil increased. Organic matter, available phosphorous and Ca contents in swine manure treatment were higher than those of chemical fertilizer (p<0.05). $NO_3$-N and $NH_4$-N concentrations in leaching water in the mixed grassland was hardly influenced by application of swine manure and urea, whereas $NO_3$-N and $NO_3$-N levels in leaching water were less than 5 ppm.

• Applied Biological Chemistry
• /
• v.35 no.5
• /
• pp.351-360
• /
• 1992

In order to improve the qualities of Doenjang were investigated on the enzyme activity in the koji and changes in chemical composition, flavors and sensory envaluation of Doenjang which were prepared with Rh. delemar koji, Asp. oryzae koji and traditional Meju with mixed koji and soybean as the ratio of optimum mixture. Asp. oryzae koji was indicated highest activities ${\alpha}$ and ${\beta}-amylase$ as 312 mg/ml, 235 mg/ml while Rh. delemar the lowest activities as 16 mg/ml, 38 mg/ml in aging for 40 days amino type ntrogen was the highest in the Asp. oryzae and Rh. delmear mixture koji(D group), Asp. oryzae(A group), and Asp. oryzae koji and Rh. delemar koji(C group) as 460 mg%, 440 mg% and 426 mg% in aging for 40 days. The main flavor components of Doenjang were detected as fellows phenol-2-kmethoxy, 4H-pyran-4-one-3-hydroxy-2-methyl, benzenthanol, 1-octan-3-ol, tetra-methyl pryrazine, 1,3,6 cyclooctatrien. Asp. oryzae(A) and Asp. oryzae koji with Rh. delemar koji mixture(C), group were the most excellent in taste, flavor color for fermented Doenjang at 40 days.

• Journal of Korean Society of Steel Construction
• /
• v.28 no.5
• /
• pp.313-323
• /
• 2016

Seven types of tests were conducted to experimentally evaluate the material properties of ultral-thick (or 120mm-thick) SM490TMC plate. The investigation of through-thickness properties was among the most significant considerations. All chemical and mechanical test results showed the through-thickness homogeneity as required and conformed to the KS(Korean industrial Standards), although the thickness was 1.5 times thicker than the thickness limit (80mm) imposed by Steel Structure Design Code. No reduction in the yield strength of 120mm-thick SM490TMC plate is recommended for design.

• Journal of Korean Society of Steel Construction
• /
• v.28 no.3
• /
• pp.173-183
• /
• 2016

Various material characteristics of HSA800 steel were examined and a quantitative criteria about the homogeneity of the strength was proposed. Whether HSA800 steel is satisfied the criteria for homogeneity of the strength or not was also examined. From the test results, the material characteristics of 1/4 point from the extreme fiber in the Z-direction satisfied the KS requirements. The excellent directional properties and impact resistance at low temperatures were also showed from the test results. HSA800 steel satisfied the criteria of homogeneity for the strength of the steel. However, it showed that some structures were banded together at 2/4 point from extreme fiber in the Z-direction from the microscopic tests and attention is needed to be paid in that point.

• Korean Journal of Food Science and Technology
• /
• v.45 no.2
• /
• pp.241-247
• /
• 2013

AOAC Mouse Bioassay Analysis (MBA) has been the gold standard for the analysis of paralytic shellfish poisoning toxin (PSP toxin) for more than 50 years. However, this method has inaccurate limit of quantification and cannot be used to determine toxic profiles. An HPLC method (PCOX) was optimized for Korean shellfish to establish an alternative or supplementary method for PSP analysis and was intended to be used for the official monitoring and regulation of food. The recovery rate of the PCOX method was 83.5-112.1% and the limit of quantification for total toxin was about $8.6{\mu}g$/100 g. A long-term comparison study showed a good correlation of the PCOX results with the AOAC MBA results: the correlation factors were 0.9534 and 0.9109 for oyster and mussel matrices, respectively. The PCOX method may be used as an alternative or supplementary method for AOAC MBA to monitor the occurrence of PSP and to analyze PSP toxin profile in oysters and mussels.

• The Journal of Engineering Geology
• /
• v.28 no.3
• /
• pp.501-512
• /
• 2018

The acid leachate derived from the sulfide mineral such as pyrite can cause problems such as aging of infrastructure and environment contamination around the civil construction site. The purpose of this study is to assess the environmental effect of an acid leachate derived from pyrite in the Miryang area under road construction. In this study, 13 samples of situ core were used for the net acid generation (NAG) experiment. The chemical composition including pH, oxidation and reduction potential (ORP) and electrical conductance of water samples produced from the NAG test was analyzed. In additional, five polished thin sections of rock cores were made for electro microprobe analyses. In the results of the NAG tests, 7 samples showed lower values than pH 3.5. It strongly indicated that these areas are under the environmental and infrastructure damage by the acid leachate. The chemical type of the 7 samples was classified as the $Fe(Ca)-SO_4$ type, which is totally a different type compared to general groundwater. The concentration of total sulfur ranges from 0.004% to 12.5%. 6 rock samples are plotted on a potentially acid forming zone in the relation diagram between the total sulfide and NAG-pH. In conclusion, it is suggested that a protection method against an environmental demage and an infrastructure corrosions by the acid leachate should be prepared in all of areas under a road construction.

• Applied Chemistry for Engineering
• /
• v.20 no.2
• /
• pp.177-185
• /
• 2009

The failure analysis of scales deposited on automotive thermostat housing has been carried out. Observations using energy dispersive spectroscopy and electron probe micro analyzer indicate that the main components of scales are some of additives of coolant used. For a detailed investigation of organic matters pyrolysis-GC/MS is employed. The result shows that the main organic component is benzoic acid and furthermore, a small amount of acetophenone, benzene and phenyl group is detected. Based on the results of failure analysis performed, the scales on automotive thermostat housing appear due to the deposition of coolant components, followed by crevice corrosion, into gap between housing and rubber horse. New accelerated test methodology, which could mimic the scale formation and the crevice corrosion on thermostat housing, is developed considering the above results. In order to reproduce the real operating conditions, the accelerating factors, i.e. temperature and humidity, are changed and programmed. The reproducibility of the accelerated test proposed is confirmed after analyzing the scales obtained from the accelerated test.

• Clean Technology
• /
• v.19 no.2
• /
• pp.90-94
• /
• 2013

We investigated one-dimensional thermal conduction for gypsum objects incorporating oyster shell powder. We presumed that according to the portion of oyster shell in the hybrid structure conductive characteristics of that would also change as some physicochemical properties such as volatile organic compound (VOC) adsorption were found to be changed considerably. Based on Fourier's 2nd law of heat conduction an analytical analysis in a flat slab (one axis perpendicular to an infinite plane) was performed. We found that composition of oyster shell and conduction-related coefficients and parameters could greatly influence on the thermal profile of that conduction, and some model experiments also served for it in the affirmative.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.1
• /
• pp.85-91
• /
• 1994

This experiment was conducted to obtain the basic information of the major chemical components for breeding high quality varieties of sweet potatoes [Ipomoea batatas (L) Lamk]. Six recommended varieties were cultivated at the experimental plots of Hwasung and Suwon in 1992. Starch value. glucose, fructose, maltose, and sucrose content were analyzed with time intervals during storage period. Starch value of Shinyulmi was the highest among six varieties in both locations. Glucose and fructose contents were appeared wide variations in varieties and locations. Shinyulmi showed the highest maltose content and Yulmi had the highest sucrose content in two locations. Total sugar contents were higher in Shinyulmi and Yulmi. Starch value, glucose, fructose, maltose, and sucrose content were stable during storage period, however these were differed between locations.