• Korean Journal of Poultry Science
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• v.28 no.3
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• pp.245-257
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• 2001

Localization of livestock facilities leads to concentration of livestock wastes and subsequent leakage of pollutants into the environment, resulting in public concern about their effects. Nitrogen (N) and phosphorus (P) are the most harmful components of animal manure, but odor from the manure itself and the livestock facilities is also a problem. Improving the nutrient efficiency of the livestock helps to decrease excretion of these environmental contaminants. Pigs and chickens are the main experimental models used in studies to improve nutrient efficiency. Addition of feed supplements and modifying feeding systems to improve nutrient efficiency can result in significant decrease in the N, P, odor and dry matter (DM) weight of manure. Examples of these methods include the following. 1) Addition of synthetic amino acids and reducing protein contents resulted N reductions of 10∼27% in broilers, 18∼35% in chicks and layers, 19∼62% in pigs, and a 9∼43% reduction in odor in pigs. 2) Enzyme supplementation resulted in a 12∼15% reduction in DM weight in broiler manure. 3) Phvtase supplementation resulted in P reductions of 25∼35% in chickens and 20∼60% in pigs. 4) Use of growth promoting substances resulted in a 5∼30% reduction in N and a 53∼56% reduction in odor of pigs. 5) Formulating diets closer to requirements (diet modification) reduced N and P by 10∼15% each in chickens and pigs, and odor by 28∼ 79% in pigs. 6) Phase feeding reduced N and P excretion by chicken and pigs from 10∼33% and 10∼13% each, as well as odor in growing and finishing pigs by 49∼79%. 7) Use of highly digestible raw materials in feed reduced N and P excretion by 5% in chickens and pigs.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.1015-1024
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• 2019

In the medical field, X-rays are essential in the diagnosis and treatment of diseases, and the use of X-rays continues to increase with the development of imaging technology, but X-rays have the disadvantage of radiation exposure. Although lead protection tools are used in clinical practice to protect against radiation exposure, lead is classified as a heavy metal and can cause harmful reactions such as lead poisoning. Therefore, the purpose of this study is to investigate the usefulness of the shield fabricated using materials of FDM (Fused Deposition Modeling) 3D printer. In order to confirm the filament's line attenuation factor, phantoms were fabricated using PLA, XT-CF20, Wood, Glow and Brass, and CT scan was performed. And the shielding sheet of 100 × 100 × 2 mm size was modeled, the dose and shielding rate was measured by using a diagnostic X-ray generator and irradiation dose meter, and the shielding rate with lead protection tools. As a result of the experiment, the CT number of the brass was measured to be the highest, and the shielding sheet was manufactured by using the brass. As a result of confirming with the diagnostic X-ray generator, the shielding rate was increased in the shielding sheet having a thickness of 6 mm upon X-ray irradiation under the condition of 100 kV and 40 mAs. It measured by 90% or more, and confirmed that the shielding rate is higher than apron 0.25 mmPb. As a result of this study, it was confirmed that the shield fabricated by 3D printing technology showed high shielding rate in the diagnostic X-ray region. there was.

• Asian Journal of Atmospheric Environment
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• v.5 no.2
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• pp.121-133
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• 2011

This study suggests criteria to conduct a risk assessment of VOCs and formaldehyde in uncontrolled public facilities. Pollutants and facilities were selected based on two years of monitoring data and exposure scenarios in 573 uncontrolled public facilities, composed of 10 types of public institutions. With the exception of social welfare facilities, lifetime ECRs of formaldehyde and benzene in each facility were higher in employees than in users, except in social welfare facilities. In social welfare facilities, the risk of benzene for users ($1{\times}10^{-5}$) was higher than that of workers ($1{\times}10^{-6}$) because facility users live in the facility 24 hours per day, compared to workers who spend an average of 8 hours per day in the facility. The risk of benzene to workers in restaurants, academies, performance halls, internet cafe and pubs were estimated as high as $1{\times}10^{-4}$ and the risk to workers in the theaters and karaoke bars were recorded as $1{\times}10^{-5}$. Because lifetime ECRs of carcinogens exceeded $1{\times}10^{-4}$ for workers and users in most facilities, risk management of formaldehyde and benzene in these facilities is necessary. Although HQs of toluene and xylenes did not exceed 1.0, their HQs did exceed 0.1 in some facilities, so they were evaluated as potentially harmful materials. Additionally, criteria for health protection in IAQ by facility are suggested at $60-100\;{\mu}g/m^3$ for formaldehyde, $400-500\;{\mu}g/m^3$ for TVOCs, $10-20\;{\mu}g/m^3$ for benzene, $150-170\;{\mu}g/m^3$ for toluene and $100\;{\mu}g/m^3$ for xylenes, based on the survey on IAQ and HRA methodology. The excess rates of IAQ to health protection criteria in all facilities were 16% for formaldehyde, 8% for TVOCs and benzene, 9% for toulene, and 5% for xylenes.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.267-276
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• 2018

Volcanic ash from volcanic eruptions spreads to vast areas hundreds of kilometers away, and when volcanic ash flows into surface waters, it will be damaged by water supply. In case of water supply facilities, it provides to people drinking water and domestic water, be consumed by the people cause social disorder when water supply is cut off due to damage such as water pollution caused by harmful materials of volcanic ash. However, when we looked at the disaster management manual, the establishment of a water supply facility manual to deal with the damage of volcanic ash was found to be insufficient. Therefore, in this study, the existing volcanic and water pollution related manuals were analyzed and problems were derived. In order to make quick situation judgment and response activities, we have suggested the scope of the water supply facility manual, disaster type, major missions and system of related organizations, and scenario of crisis situation by disaster type.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.706-714
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• 2020

Currently, 90 % of the world's population breathes air with a fine dust content exceeding the World Health Organization's annual average exposure limit (10 ㎍/㎥). Global efforts have been devoted toward reducing secondary pollutants and ultra-fine dust through regulations on nitrogen oxides released over land and sea. Domestic efforts have also aimed at creating clean marine environments by reducing sulfur emissions, which are the primary cause of dust accumulation in ships, through developing and distributing environment-friendly ships. Among the technologies for reducing harmful emissions from diesel engines, electrostatic precipitator offer several advantages such as a low pressure loss, high dust collection efficiency, and NOx removal and maintenance. This study aims to increase the durability of a ship by improving equipment quality through failure mode effects analysis for the preventive maintenance of an electrostatic precipitator that was developed for reducing fine dust particles emitted from the 2,427 kW marine diesel engines in ships with a gross tonnage of 999 tons. With regard to risk priority, failure mode 241 (poor dust capture efficiency) was the highest, with an RPN of 180. It was necessary to determine the high-risk failure mode in the collecting electrode and manage it intensively. This was caused by clearance defects, owing to vibrations and consequent pin loosening. Given that pin loosening is mainly caused by vibrations generated in the hull or equipment, it is necessary to manage the position of pin loosening.

• Analytical Science and Technology
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• v.27 no.2
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• pp.108-113
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• 2014

The harmful materials as volatile organic compounds (VOCS) that is easy for gas to be changed from liquid on ambient temperature, those should be controlled by Korea Chemicals Management Association. The VOCs samples should be collected directly in place so that those could be analyzed. Generally but it couldn't avoid to have the risk of analyst. Moreover, if there is the place limited to entrance, it is impossible to collect directly and measure. Owing to such problem, it tried to be solved by open path FT-IR spectrometer that could be studied on the combustion gases within long path and VOCs samples were tried to measure to large volume by remote and real time. Firstly, it was to investigate optimized measured length between the system and benzene sample of VOCs. As result, The optimized measured length was confirmed with 15 meter length and the qualitative analysis could be measured on seven VOC samples. The calibration curve as quantitative analysis of benzene samples could be worked. On the basis of the result, the system as remote monitor could show to have potentiality.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.140-148
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• 2011

The official analytical method of residue pesticides in herbal medicines by KFDA cannot be applied to all of the pesticides and herbal medicines because of various active materials in herbal medicines and various physicochemical properties of pesticides. Moreover, liquid-liquid partition uses harmful solvents such as methylene chloride and is consuming a lot of time and effort. In order to improve the problems, we have studied for the availability of the analytical method applying the macroporous diatomaceous earth (MDE) column instead of liquid-liquid partition to simultaneously analyze five pesticides in two dried herbal medicines. The results showed that the recovery rates of acetamiprid and azoxystrobin in Astragalus root by GC/ECD ranged from 89.6 to 94.1%, from 86.8 to 94.4%, respectively, and those of bifenthrin, chlorfenapyr, chlorpyrifos in Cnidii Rhizoma by GC/MS ranged from 83.6 to 88.4%, from 77.4 to 83.8%, from 82.6 to 84.3%, respectively. Also, the coefficients of variation (CV) for triplication ranged from 0.5 to 1.7%. The results satisfied the criteria of residue pesticide analysis, setting 70~120% for the recovery rate and below 10% for the coefficient of variation. The improved methods are safer to residue pesticide analysts, faster and less laborious than the KFDA official method.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.867-873
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• 2010

This study investigated the corrosion properties of reinforced concrete with the addition of steel fibers. The transport properties of steel fiber-reinforced concrete such as permeable void, absorption by capillary action, water permeability and chloride diffusion were first measured to evaluate the relationship with the corrosion of steel rebar. Test results showed a slight increase on the compressive strength with the addition of steel fibers as well as considerable improvement of penetration resistance to mass transport of harmful materials into concrete. The addition of steel fibers in reinforced concrete accelerated the initiation of steel corrosion contrary to the expected results based on the measured transport properties. The NaCl ponding surface showed the spalling failure due to the corrosion expansion of steel fibers and the cut-surface around the steel rebar showed the localized steel fiber's corrosion. The wet-dry cycling with high chloride ions as well as high temperature seems to induce the increase of salt crystallization on the pores continually and the increased pressure with the steel fiber's corrosion on the pores caused the spalling failure on the exposed surface. The microcracking on the surface therefore accelerated the movement of water, chloride ions and oxygen into the embedded steel rebar. The mechanism affecting corrosion of embedded steel reinforcement with steel fibers in this study are not yet fully understood and require further study comprising of accurate experimental design to isolate the effect of steel fiber's potential mechanism on the corrosion process.

• 한국가시화정보학회:학술대회논문집
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• 2002.04a
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• pp.51-78
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• 2002

A number of research groups worldwide are studying electronic implants that can be mounted on retinal optic nerve/visual cortex to restore vision of patients suffering from retinal degeneration. The implants consist of a neural interface made of biocompatible materials, one or more integrated circuits for stimuli generation, a camera, an image processor, and a telemetric channel. The realization of these classes of neural prosthetic devices is largely due to the explosive development of micro- and nano-electronics technologies in the late $20^{th}$ century and biotechnologies more recently. Animal experiments showed promise and some human experiments are in progress to indicate that recognition of images can be obtained and improved over time. We, at NBS-ERC of SNU, have started our own retinal implant project in 2000. We have selected polyimide as the biomaterial for an epi-retinal stimulator. In-vitro and in-vivo biocompatibility studies have been performed on the electrode arrays. We have obtained good affinity to retinal pigment epithelial cells and no harmful effect. The implant also showed very good stability and safety in rabbit eye for 12 weeks. We have also demonstrated that through proper stimulation of inner retina, meaning vision can be obtained.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.423-427
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• 2013

This research was carried out to identify the characteristics of the wastewater from coke oven gas (COG) purification process of the coke plant, and derive optimal operating conditions for the treatment of wastewater. The coke plant wastewater contains highly concentrated $S^{-2}$ and $SCN^-$ that are harmful to microorganisms, and their concentrations were 6.8~11.2 mg/L and 190~320 mg/L, respectively. When the $S^{-2}$ ion concentration was lower than 10 mg/L, $SV_{30}$ of active sludge was 280~ 340 mL and the sludge sedimentation velocity was very fast. But, when the $S^{-2}$ ion concentration was higher than 15 mg/L, $SV_{30}$ of the active sludge was 560~680 mL and the sludge sedimentation velocity was very slow. Also when the $SCN^-$ ion concentration was lower than 300 mg/L, $SV_{30}$ of the active sludge was 245~320 mL and the sludge sedimentation velocity was very fast. But, when the $SCN^-$ ion concentration was higher than 400 mg/L, $SV_{30}$ of the active sludge was 470~ 567 mL and the sludge sedimentation velocity was slow. To treat the wastewater generated by COG purification process of the coke plant effectively and to maintain microorganism activities in good conditions, the ion concentration of $S^{-2}$ and $SCN^-$ should be lower than 15 mg/L and 400 mg/L, respectively.