• Journal of Ocean Engineering and Technology
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• v.27 no.1
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• pp.109-114
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• 2013

Regulations on exhaust emissions for vehicles and ships are reinforced. Therefore, researchers are focus on developing an excellent engine that emits less environmental pollutants and leads to high gas milage. The purpose of this study is to investigate the efficiency of intake super charging system. Super charger is the special device for improving performance of intake system. Futhermore, for reducing exhaust emissions, the examine are performed on the effectiveness of device structures that tow materials for performance improvement. To fulfill the purpose, Super charger materials of aluminum alloy(AL6262) and polycarbonate were selected and then their temperature change of super charger and inhalation efficiency were analyzed by ANSYS program. In addition, it is attempted to apply these results to device development by comparing the results with the real value. As a result, there was less temperature change of super charger in aluminum materials than polycarbonate, and HC and NOx were decreased when the super charger was installed.

• The Korean Journal of Applied Statistics
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• v.8 no.2
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• pp.27-41
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• 1995

In this paper, the proportion of durg-abuse and gas/bond-inhalation among the high school students in Kwangju and Chonnam has been estimated using the survey of the Black-Box method and randomized response technique. We have analyzed empirically the effects of both methods for the surveys of sensitive characters.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1029-1037
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• 2008

As for track maintenance, Seoul Metro executes track bed improvement project from obsolete ballast track bed to concrete track bed in order to achieve maintenance free and to extend its LCC(Life Cycle Costing). When it comes to obsolete ballast track bed withdrawal task, now it is done solely relying on man power and ballast inhalation vehicle. In this paper, I suggested ballast cleaning system with lighter equipment to change manpower withdrawal tasks to mechanized ones. It is expected to improve work efficiency and economic benefits by applying track excavator having variable wheels and container etc, which is able to keep on the site.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.163-163
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• 2003

Difficulties of long-tenn survival of lung cancer patients treated with conventional therapies require the need for novel approaches and gene therapy holds promise in this area. Several genes are known to have anti-tumor activities and have been used as a gene of delivery, however, a number of problems such as efficiency, specificity of the gene delivery hinder the application of gene therapy.(omitted)

• Journal of Environmental Health Sciences
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• v.36 no.5
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• pp.402-410
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• 2010

The objectives of this study were to evaluate the air quality surrounding an indoor swimming pool, to estimate the cancer risk based on the airborne exposure to trihalomethanes (THMs), and to examine the ventilation efficiency by Computational Fluid Dynamics (CFD). Chlorine and THMs were measured poolside, and in the staff room and reception area. The indoor swimming pool was modeled using the Airpak program, with ventilation drawings and actual survey data. Temperature, flow and mean age of the air were analyzed. Levels of chlorine poolside, and in the staff room, and reception area were $203\;{\mu}g/m^3$, $5\;{\mu}g/m^3$, and $10\;{\mu}g/m^3$, respectively. Chloroform was the dominant THM in all sampling sites and mean concentrations were $16.30\;{\mu}g/m^3$, $0.51\;{\mu}g/m^3$, and $0.06\;{\mu}g/m^3$ poolside, in the staff room and reception area, respectively. Bromodichloromethane and Dibromochloromethane levels were respectively estimated as $10.3\;{\mu}g/m^3$ and $1.7\;{\mu}g/m^3$ poolside, $1.3\;{\mu}g/m^3$ and $0.1\;{\mu}g/m^3$ in the staff room, and were not detected in the reception area. The cancer risks from inhalation exposure to THMs were estimated between $3.37{\times}10^{-7}$ and $1.84{\times}10^{-5}$. A short circulation phenomenon was observed from the supply air vents to the exhaust air vents located in the ceiling. A high temperature layer was formed within one meter of the ceiling, and a low temperature layer was formed under this layer due to the low velocity and high temperature of the supply air, and the improper locations of the supply air vents and exhaust air vents. The stagnation was evident at the above adult pool and the mean age of the air was 22 minutes. Disinfection by-products in the indoor swimming pool were present in higher concentrations than in the outdoor air. In order to increase the removal of pollutants, adjustment was required of the supply air volume and the supply/exhaust position.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.150-150
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• 2016

Mankind is enjoying a great convenience of their life by the rapid growth of secondary industry since the Industrial Revolution and it is possible due to the invention of huge power such as engine. The automobile which plays the important role of industrial development and human movement is powered by the Engine Module, and especially Diesel engine is widely used because of mechanical durability and energy efficiency. The main work mechanism of the Diesel engine is composed of inhalation of the organic material (coal, oil, etc.), combustion, explosion and exhaust Cycle process then the carbon compound emissions during the last exhaust process are essential which is known as the major causes of air pollution issues in recent years. In particular, COx, called carbon oxide compound which is composed of a very small size of the particles from several ten to hundred nano meter and they exist as a suspension in the atmosphere. These Diesel particles can be accumulated at the respiratory organs and cause many serious diseases. In order to compensate for the weak point of such a Diesel Engine, the DPF(Diesel Particulate Filter) post-cleaning equipment has been used and it mainly consists of ceramic materials(SiC, Cordierite etc) because of the necessity for the engine system durability on the exposure of high temperature, high pressure and chemical harsh environmental. Ceramic Material filter, but it remains a lot of problems yet, such as limitations of collecting very small particles below micro size, high cost due to difficulties of manufacturing process and low fuel consumption efficiency due to back pressure increase by the small pore structure. This study is to test the possibility of new structure by direct infiltration of SiC Whisker on Carbon felt as the next generation filter and this new filter is expected to improve the above various problems of the Ceramic DPF currently in use and reduction of the cost simultaneously. In this experiment, non-catalytic VS CVD (Vapor-Solid Chemical Vaporized Deposition) system was adopted to keep high mechanical properties of SiC and MTS (Methyl-Trichloro-Silane) gas used as source and H2 gas used as dilute gas. From this, the suitable whisker growth for high performance filter was observed depending on each deposition conditions change (input gas ratio, temperature, mass flow rate etc.).

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.343-349
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• 2012

Exposure and risk assessments were conducted to evaluate the relative safety of mixing/loading work of indoxacarb between wettable powder (WP) and water dispersible granule (WG). Hand exposure was monitored using cotton gloves while inhalation exposure was measured using personal air monitor. Method validation for the exposure monitoring was established successfully through several experiments. Limit of determination and limit of quantitation were 0.25 and 1 ng, respectively. $R^2$ of calibration curve linearity was more than 0.9999 and reproducibility was 0.7-6. Recovery of indoxacarb from gloves, solid sorbent and glass fiber filter at three different levels was 81.5-108.8%. Trapping efficiency and breakthrough tests gave 981.5-108.8% of recovery. During mixing/loading procedure, hand exposure amount (75 percentile of 30 repetitions) for indoxacarb WP was 6 folds (459.8 mg/kg a.i) than that of WG (81.4 mg/kg a.i). This result indicates that WG has less drift than WP thanks to its granular type of formulation. Inhalation amount was $10^{-8}-10^{-7}%$ of spray mixture prepared and $10^{-4}-10^{-3}%$ of hand exposure. In inhalation case, no significant differences were observed between two formulations. Margin of safety was calculated for risk assessment using male Korean average body weight and acceptable operator exposure level as the important exposure factors. Mixing/loading procedures for both of the formulations were considered to be of least risk because calculated MOS values were more than 1.

• Science of Emotion and Sensibility
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• v.17 no.2
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• pp.85-90
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• 2014

The purpose of the study is to develop self-management system that people can enhance physical and psychological health through repeating by themselves to relieve work-related stress. The regular respiration can help homeostasis of heart to maintain. Also the effect can be stabilized from irregular heart rhythm by work-related stress. People have optimal respiration cycle to stabilize heart rhythm and repeat training using their RSP(respiration) time including expiration and inhalation. This system is not only offering optimal respiration training service but also finding optimal respiration cycle. The adults who have stress from work participated in verification experiment. This study expects to help those people who are workers related to call center jobs in emotional labor can relieve their stress. It can also help to enhance their own health and increase their work efficiency.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.283-290
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• 2017

Objectives: This study aimed to evaluate the relationship between filter replacement and filter performance change in particulate filters used in the workplace. Methods: Three types of particulate respirator filters are mainly used in the workplaces. These were tested against the filter performance safety certification standard for dust masks established by the Ministry of Employment and Labor(MoEL). Used filters were collected to test their performance, such as filter pressure drop, efficiency, and quality factors. All these factors were evaluated by a filter tester. To compare filter performance between used and new ones, the same kinds of new filters were also tested together under the same procedures. Results: A total of 270 used filters were collected for testing. The main reasons to replace the filters were difficulty in breathing(46.2%), dirty/odor influx(19.7%), and a combination of factors(26.7%). The pressure drop for two special class groups was significantly different(new filters: $20.72{\pm}3.33mmH_2O$; used filters: $24.70{\pm}5.26mmH_2O$, p<0.0001). In the case of penetration, new filter groups indicated $0.0032{\pm}0.0040%$, while that of the used filters was $0.0596{\pm}0.1187%$. The quality factor for the used filters($0.34{\pm}0.09$) significantly decreased compared to the new filters($0.53{\pm}0.08$) (p<0.0001). Conclusions: Filter performance including pressure drop, penetration, and the quality factor was evaluated and compared between new and used filters in the workplace. The results showed that general filter performance deteriorated more for change of pressure drop, penetration and the quality factor.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.845-852
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• 2007

An OWC-type Wave Energy Conversion passes through 3 steps energy conversion process. This paper deal with the impulse turbine with staggered blade to improved performance by numerical analysis using commercial CFD code, FLUENT Maximum value of axial airflow velocity during exhalation is higher than that during inhalation This paper deal with special-type of Impulse Turbine so-called "Staggered Blade" for more efficiency to making air flow direct to on pressure side. Also, this paper has proposed special-type turbine with self-pitched blade more efficient.