• Journal of Korea Water Resources Association
• /
• v.47 no.3
• /
• pp.247-256
• /
• 2014

A company, which is chicken butcherying-plant, was scheduled to increase up to twice output. We researched the way to increase up to twice the processing efficiency at the target biological treatment tank of A company. We performed for this study to obtain the reason why organic matter and nitrogen removal efficiency is increased when MLSS concentration is increased. It's performed at the target of pressure flotation water on SBR system. We performed the research which MLSS was 12,700 mg/L for 30hours (in aerobic condition for 25 hours and in anoxic condition for 5 hours). As a result, the nitrification was happened completely in aerobic condition within 25 hours. Denitrification efficiency was also over 90% when C/N ratio was over 3:1. After the experiment, we changed the concentration of MLSS 5,600 to 12,700 mg/L. In condition MLSS was about 11,000 mg/L and HRT were 30 hours meet the Effluent quality standard.

• Applied Chemistry for Engineering
• /
• v.19 no.4
• /
• pp.376-381
• /
• 2008

The deactivation of $V/TiO_2$ catalyst used in SCR (Selective Catalytic Reduction) using ammonia as a reductant to remove the nitrogen oxides (NOx) in the exhaust gas from fired power plant has been studied. The activity and surface area of the catalyst (Used-cat) which was exposed to the exhaust gas for long period have considerably decreased. The characterizations of these SCR catalysts were performed by XRD, FT-IR, FE-SEM, and IC/ICP. The crystal structure of $TiO_2$ both fresh and used catalyst has not been changed. However, $(NH_4)HSO_4$ deposited on the used catalyst surface verified from FT-IR, FE-SEM, and IC/ICP analysis. Moreover, the durability of $SO_2$ was increased by diminishing sulfate ($SO_4^{-2}$)f form.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.25 no.2
• /
• pp.257-265
• /
• 2017

In this work, the effect of field-degradation of automotive polymeric interior parts on the squeak characteristics was studied for a number of used vehicles with various mileages and years of service. The purpose of this study was to characterize the squeak noise related with long-term degradation in service life. The characteristics of field-degraded polymeric samples are analyzed using Fourier transform infrared(FT-IR) spectroscopy and scanning electron microscopy(SEM). Complicated carbonyl spectra from FT-IR were deconvoluted into various carbonyls to trace field-degradation phenomenon. In addition, various mechanical tests, i.e. tensile test, hardness test as well as coefficient of friction test, were performed to analyze the variation in mechanical properties due to field-degradation. Squeak noise was measured and analyzed by frequency analysis. It was shown that the changes in the chemical structures of polymer due to field-degradation influenced the variation in mechanical properties, and squeak noise may worsen by increasing the squeak noise level in the wide frequency range. The results indicated that customer complaints regarding the squeak noise coming from used vehicles might be one of the important reliability issues because the increase in sound pressure level especially in the high frequency range could annoy drivers and passengers.

• Korean Journal of Food Science and Technology
• /
• v.22 no.3
• /
• pp.319-324
• /
• 1990

The effects of pH, protein and fat content, addition of emulsifiers, stabilizer, sugar, salt and calcium salt on the stability of soymilk suspension were investigated by analyzing the cream separated and precipitates of soymilk which is prepared by various conditions. In the alkaline region of pH, soymilk showed a good stability of the suspension and particularly, above pH 10, precipitates were not formed. When 1.5% of palm oil with 0.4% of glycerine monostearate was added to soymilk in the hydrophile-lipophile balance (HLB) value of 4 to 7, resulted maximal emulsion stability occured below H LB 6. The stability was decreased with increasing the fat concentration and soy oil showed better emulsion stability than that of palm oil. Among the commercial stabilizers, 0.03% of carrageenan was most effective. The stability was not decreased by addition of sugar up to 3% while it was decreased by addition of sodium salt and calcium salt at low level.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.3
• /
• pp.125-132
• /
• 2006

Transient kinetics of $NH_3$ adsorption/desorption and of SCR(selective catalytic reduction) of NO with $NH_3$ were studied over vanadium based catalysts, such as $V_2O_5/TiO_2$ and $V_2O_5-WO_3/TiO_2$. In the present catalytic reaction process, NO adsorption is neglected while $NH_3$ is strongly chemisorbed on the catalytic surface. Accordingly, it is ruled out the possibility of a reaction between strongly adsorbed $NH_3$ and NO species in line with the hypothesis of an Eley-Rideal mechanism. The present kinetic model assumes; (1) non-activated $NH_3$ adsorption, (2) Temkin-type $NH_3$ coverage dependence of the desorption energy, (3) non-linear dependence of the SCR reaction rate on the $NH_3$ surface coverage. Thus, the surface heterogeneity for adsorption/desorption of $NH_3$ is taken into account in this model. The present study extends the pure chemical kinetic model based on a powdered-phase catalytic system to the chemico-physical one applicable to a realistic monolith reactor.

• Journal of the Korea Institute of Building Construction
• /
• v.16 no.2
• /
• pp.125-131
• /
• 2016

According to the increment of urban buildings, the demand of eco-environment space will be also increased. Therefore, the artificial ground green system on a roof will be supplied gradually. In this study, the concept of simplification, unification and prefabrication was widely applied to supply green system. Consequently, the box unit system with a continuous soil layer was developed, and adhesive property, wind resistance and insulation property of this system were evaluated for site application. As a results of adhesive property and wind resistance test, comparing with design wind pressure and wind velocity, this system was safe at the height of 100m building located in urban. In addition, results of temperature measurement for 120 days showed 17% higher insulation property at daytime and 45% higher insulation property at night than normal box unit system owing to continuous soil layer.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.4
• /
• pp.391-396
• /
• 2015

The demands about eco friendly space are increased as buildings are denser in downtown, and green system on the roof and the artificial ground are widely being applied. The construction of green system applies a waterproof layer, a root barrier and a protection concrete layer. Assembly of these many layers leads to a long construction term, and cause many defects. This study is to evaluate one layer-hybrid sheet which gets waterproof and root barrier performance simultaneously, which is developed to use in the new green system. As results, the performances of physical properties, durability, waterproof and root barrier not only exceeded quality standards but also showed excellent durability. In addition, mock-up test would be proceed to certify long term performance.

• Korean Journal of Environmental Agriculture
• /
• v.32 no.4
• /
• pp.273-278
• /
• 2013

BACKGROUND: Total petroleum hydrocarbons (TPH), which are main materials of soil contamination by oil, are a term used for any mixture of hydrocarbons. Korea Ministry of Environment established the maximum permissible level of TPH in farmland by 500 mg/kg, and reported that the TPH level of soil in 266 installation such as gas station, transport company, and military unit ranged from 1,356 to 55,117 mg/kg and were much higher than the maximum permissible level in 2011. METHODS AND RESULTS: To determine the effect of TPH on crops, we investigated the effect of gasoline, kerosene, and diesel on the germination and radicle growth of mainly consumed crops. The germination rates of control in investigated all crops ranged from 80.0-100%. The germination and radicle growth in majority of investigated crops were not inhibited even at 2,500 mg/L. However, germination in onion, leek, and green perilla and radicle growth in leek, rape, tomato, and green perilla were significantly inhibited by increasing concentrations of gasoline, kerosene and diesel treatment. Germination and radicle growth inhibition of green perilla by kerosene and diesel were the highest, the percent inhibition at the 500 mg/L were 100 and 98.6%, 100 and 88.2%, respectively. 50% inhibition of germination in green perilla by kerosene and diesel were 39.96 and 29.87 mg/L, and 50% inhibition of radicle growth were 52.76 and 177.96 mg/L, respectively. Conclusion(s): These results suggest the possibility that the maximum permissible level of TPH might to be established general level with exception by crops.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.19 no.3
• /
• pp.152-158
• /
• 2009

Various fabrication methods have been used to synthesize sapphire which has qualities of jewelry well beyond the industrial class. Among them, the flux sapphire of Chatham Company which has as high value as jewelry was selected in order to compare natural and synthetic sapphire. First, the WD-XRF (Wavelength dispersive x-ray fluorescence spectrometer) was used to analyze the chemical composition of natural and synthetic sapphire. Although natural sapphire had very diverse chemical compositions, flux sapphire had small quantities of Mo, Pt and Pb elements in addition to the similar chemical ingredients to natural one. Pt is decisive proof of flux sapphire. Next, by investigating spectroscopic characteristics using UV-VIS Spectrophotometer after heat treatment at high temperatures of $1300^{\circ}C$ and $1500^{\circ}C$, the variation of 690 nm absorbance related to $Cr^{3+}$ was detected in the natural sapphire while those of the 690 nm absorbance (related to $Cr^{3+}$) as well as absorbance of 376 nm and 388 nm ($Fe^{3+}$) were seen in the flux sapphire. It was found that the difference in the absorbance variation of flux sapphire is greater than that of natural sapphire after heat treatment. The chemical composition and spectrum analysis were utilized to compare the natural sapphire and the flux synthetic sapphire.

• Economic and Environmental Geology
• /
• v.44 no.1
• /
• pp.37-48
• /
• 2011

Some industrial minerals used in domestic industries such as monazite, apatite, bauxite, and ilmenite belong to NORM (Naturally Occurring Radioactive Materials) because they show a high radioactivity. Products, semi-products, wastes, and by-products which show higher radioactivity than NORM belong to TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials). Apatite used for manufacturing phosphate fertilizer in Namhae Chemical company belongs to NORM, and its by-product, phospo-gypsum, belongs to TENORM. A geological investigation is needed for the future environmental impact assessment of the Namhae Chemical company's site. According to survey results of the Namhae Chemical company's site, soil mineral composition indicated the mixture of minerals derived from the country rock (quartz, feldspar, mica, $l4{\AA}$ mineral, kaolin and amphibole) and minerals from the gypsum open-air storage yard (gypsum and apatite). Soil samples showed average content of U 4.6 ppm and Th 10 ppm, which are similar to average crustal abundances. They also show average contents of $^{40}K$ 191-1,166 Bq/kg, $^{226}Ra$ 15.6-710 Bq/kg, and $^{232}Th$ 17.4-72.7 Bq/kg, which indicate moderate levels of radio nuclide. But $^{226}Ra$ anomaly in the gypsum open storage yard is clearly confirmed and $^{232}Th$ anomaly is also confirmed in the east road side of the factory and nearby mountain areas. Soil external hazard indices ranged 0.24-2.01 with the average 0.54. Although most external hazard indices were lower than 1, which means radiation hazard index to be negligible, 5 samples out of total 40 samples showed higher values than 1, and further detailed investigation is needed.