• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.175-180
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• 2009

In this study, the basic data were collected for improving the amenity of indoor environment of a super yacht and the performance of indoor environment was analyzed by utilizing measured data during summer period. Through the results of examination, the following conclusions are drawn. 1) It is estimated that, in case of closing the door of Saloon connected with outside, there is little inflow of exhaust gas, but when the door is open, the indoor-air might be polluted so fast. Therefore, it is necessary to make a counter plan about the method of ventilation and amount of ventilation to keep the indoor aerial environment agreeable. 2) It is urgent to conceive countermeasure against engine noise because the noise level of all rooms exceeds 60dB, which is regulation of noise for protecting crew established in ship's classification, during the sailing. 3) State cabin and Guest cabin are super cooled by operating air conditioner exceeding agreeableness extent and it is needed to prevent them.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.369-378
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• 2000

The purpose of this study is to developed high-efficient rotary tillage system for a power tiller by improving the rotary blade. A kind of the rotary blade with single-edged blade(DS) was developed that requires lower tillage energy than conventional double-edged blade(CD) on the design theory for Japanese rotary blade. In order to find out the tillage characteristics between the single-edged blade and the double-edged blade for power tiller, experiments were performed in soil-bins which were filled up clay loam, loam and sandy loam, and then analyzed the effects of the factors such as soil texture, travelling speed, rotational speed, and tillage depth to each of the blades. And field tests were carried out to compare tillage performances of the two blades using rotary cultivator driven by conventional power tiller. The results of this study were summarized as follows; 1) On the soil bin experiment, it was found that tillage torque of the single-edged blade was less than the ones of the double-edged blade. The decreasing ratios of maximum tillage torque of the single-edged blade to the ones of the double-edged blade were 1 to 8% at clay loam, 5 to 20% at loam and 9 to 31% at sandy loam, respectively. 2) By the field tests, that the tillage performances with the single-edged blade compared with the double-edged blade was improved about 19% in field capacity, about 34% in fuel consumption, and 12.5% in soil breaking ratio. Furthermore, the fluctuation of engine speed, the variation of exhaust gas temperature, and the amount of soil clogging on the blade and straw wound on the rotary shaft showed lower values with the developed blade than the conventional blade. So, it may be concluded that tillage performance by the developed single-edged blade was improved compared with the one by the conventional double-edged blade.

• Journal of radiological science and technology
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• v.46 no.2
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• pp.141-149
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• 2023

The Korea Institute of Radiological and Medical Sciences plans to produce ²²⁵Ac, a therapeutic radio-pharmaceutical for precision oncology, such as prostate cancer. Radon, a radioactive gas, is generated by radium, the target material for producing ²²⁵Ac. The radon concentration is expected to be about 2000 Bq·m^-3. High-concentration radon-generating facilities must meet radioactive isotope emission standards by lowering the radon concentration. However, most existing studies concerning radon removal using activated carbon filters measured radon levels at concentrations lower than 1000 Bq·m^-3. This study measured ²²²Rn removal of coconut-based activated carbon filter under a high radon concentration of about 2000 Bq·m^-3. The ²²²Rn removal efficiency of activated carbon impregnated with triethylenediamine was also measured. As a result, the ²²²Rn removal amount of the activated carbon filter showed sufficient removal efficiency in a ²²²Rn concentration environment of about 2000 Bq·m^-3. In addition, despite an expectation of low radon reduction efficiency of Triethylenediamine-impregnated activated carbon, it was difficult to confirm a significant difference in the results. Therefore, it is considered that activated carbon can be used as a radioisotope exhaust filter regardless of whether or not Triethylenediamine is impregnated. The results of this study are expected to be used as primary data when building an air purification system for radiation safety management in facilities with radon concentrations of about 2000 Bq·m^-3.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.252-256
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• 2015

Nitrogen oxides ($NO_X$) was emitted from flue gas of stationary sources and exhaust gas of mobile sources, can leads to various environments problems. Selective Catalysts Reduction (SCR) is the most effective $NO_X$ removal system. Commercial $V_2O_5-WO_3/TiO_2$ catalysts, usually containing $V_2O_5$ 0.5~3 wt%, $WO_3$ 5~10 wt%, and $V_2O_5$ is active in the reduction of $NO_X$ but also in the desired oxidation of $SO_2$ to $SO_3$. To reduce the amount of vanadium, using graphene matrix supported vanadium to synthesize nanocomposite. Then, we fabricated to 1 inch honeycomb type of SCR catalysts adding graphene-vanadium nanocomposite. The chemical-physical characteristics and the catalytic activity were performed by XRD, XRF, BET and Micro-Reactor (MR). As a result, the De-NOX performance was showed, similar to the commercial catalyst activity as 77.8 % and using nanocomposite catalyst as 77.1 % at $350^{\circ}C$.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.328-336
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• 2005

In order to remove the NO contained in exhaust gas by the non-selective catalyst reduction method, the catalysts were prepared by varing the loading amount of Ag and V into ${\gamma}-Al_2O_3$. The conversion of $NO_x$ using the prepared catalysts was studied by varying the temperatures, $O_2$ concentrations and $SO_2$ concentrations using. The influence of the catalyst structure on $NO_x$ conversion was studied through the analysis of the physical properties of the prepared catalysts. In the case of $AgV/{\gamma}-Al_2O_3$ catalyst, the $NO_x$ conversion was lower than that of $Ag/{\gamma}-Al_2O_3$ at higher temperatures but higher than that of $Ag/{\gamma}-Al_2O_3$ at lower temperatures. Even though $SO_2$ was contained in the reaction gas, the $NO_x$ conversion did not decrease. Based on the analysis including XRD, XPS, TPR, and UV-Vis DRS before and after the experiments, the experimental results were examined. The results indicated that, $NO_x$ conversion decreased at higher temperatures since Ag oxide could not be maintained well due to the addition of V, whereas it increased at temperatures lower than $300^{\circ}C$ due to the catalytic action of V.

• Plant Journal
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• v.13 no.2
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• pp.46-51
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• 2017

In this study, the boiler efficiency and the change of boiler combustion state with the burner operation of the uppermost layer of 870MW opposite fired coal boiler were measured. Test results showed that the boiler efficiency was high in the order of the uppermost layer simultaneous operation of the front and rear burners, the front burner, and the rear burner operation. When the front and rear burners were operated simultaneously, the heat absorption rate of water walls in the boiler furnace was uniform at four side, and the temperature deviation of the left and right steam on the convection front surface decreased. As the heat absorption rate of the boiler improved, the loss of boiler exhaust gas decreased and the coal supply amount decreased by 8 tons/hour compared to the operation of the rear burner. This will contribute not only to the reduction of fuel cost but also to the reduction of greenhouse gas emissions.

• Clean Technology
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• v.16 no.4
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• pp.284-291
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• 2010

Nitrous oxide ($N_2O$) is a greenhouse material which is hard to remove. Even with a catalytic process it requires a reaction temperature, at least, higher than 670 K. This study has been performed to see the effects of Ce addition to the mixed oxide catalyst which shows the highest activity in decomposing $N_2O$ completely at temperature as low as 473 K when CO is used as a reducing agent. Mixed metal oxide(MMO) catalyst was made through co-precipitation process with small amount of Ce added to the base components of Co, Al and Rh or Pd. Consequently, the surface area of the catalyst decreased with the contents of Ce, and the catalytic activity of direct decomposition of $N_2O$ also decreased. However, in the presence of CO, the activity was found high enough to compensate the portion of activity decrease by Ce addition, so that it can be ascertained that the catalytic activity and stability can be maintained in the CO involved $N_2O$ reduction system when Ce is added for the physical stability of the catalyst.

• Journal of Preventive Medicine and Public Health
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• v.2 no.1
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• pp.5-22
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• 1969

The urban population of our country is rapidly increasing due to many factors of social structure, and sociologists are predicting that the increase rate of the urban population will be over 50% in 1980's. Above all, the population of the capital city of Seoul, is at present more than four millions. Such centring of people in cities, together with the improvement of the standards of living, caused rapid increase in the amount of fuel consumption, and this consumption of fuels became one of the primary sources of the air pollution in cities. Moreover, the heavy traffic, construction of many tall buildings, and the increasing number of new factories due to the industrial development-all these are contributing to make the matter of air pollution worse and worse in the Metropolitan, whose geographical location is quite unfavorable considered from the view point of air pollution. Most homes in Seoul use briquet as fuel, while oils are used in tall buildings. The CO, $SO_2$, and smoke that come from burning of these fuels are a great threat to the health of the urban population. With the purpose of examining the influence of air pollution upon the public health, written inquiries were made upon respiratory diseases, and the carboxyhemoglobin saturation in the blood was measured to determine whether the air pollution may affect the health of the urban population. Method of Health Examination (1) Investigation of Respiratory Diseases Patients' records were examined to figure out the monthly ambulance rate of respiratory patients to the total number of patients treated. On the other hand, by using the questionnaire form approved by the Medical Research Council's Committee on Research into Chronic Bronchitis, investigators interviewed the examinees and inquired into the respiratory symptoms. (2) Measuring of Carboxyhemoglobin Saturation From the ear lobe of the examinees, with the use of the melangeur for the white blood cell counting, blood was taken, and after diluting it ten times with 0.1% $Na{2}CO_{3}$, again diulting it 20 times with 0.5% $Na_{2}\;CO_{3}$, its absorbancy was measured. The following results are obtained from the investigation. (1) It was found out that 7.7% of the total patients under treatment were suffering from upper respiratory infection, acute or chronic bronchitis, bronchial asthma, pulmonary emphysema and bronchiectasis. Of them all, patients with upper respiratory infection numbered the greatest with 4.8% and patients with acute or chronic bronchitis the next with 2.1%, and their monthly ambulance rate was high from December to February during the winter, and from April to May and from September to October during the changeable seasons. (2) The daily ambulance rate of respiratory patients, it was revealed, had a close connection with the concentration of $SO_2$ and CO in the air. (3) It was found out that men were more subject to respiratory disease than women, and both men and women were more liable to the diseases with the advancing of age. (4) People living at Choong-ku with the heavy traffic and in the industrial zones of Yeungdungpo had high frequency of respiratory symptoms. (5) Considered from the view point of occupations, high frequency was found among those without job, with jobs unknown, merchants and intdustrial workers, whose social status was rather low and traffic policemen who were always exposed to the exhaust gas of cars. As for women, the frequency was detected in the order of those from high to low, housewives who were exposed to briquet gas, women with jobs unknown, women without jobs, whose social status was low. (6) Ex-smokers rather than smokers, of both sexes, had higher frequency. As for men, heavy smokers had high frequency, while in women light smokers had rather high frequency which was presumed to be due to their average old age. (7) Men's average of carboxyhemoglobin saturation was 9.48%, while women's was 11.3%, higher than men's. (p<0.05). Age meant no difference in the case of men, but as for women, the saturation was remarkably high between the ages from 20 to 60. (8) No regional difference was detected in the carboxyhemoglobin saturation. (9) The carboxyhemoglobin saturation was found, in the case of men, in the order of office workers, traffic policemen, students, the unemployed, merchants and industrial workers, drivers; and as for women, the order was housewives, office workers, merchants and industrial workers. (10) No significant correlation was found between the carboxyhemoglobin saturation and the concentration of CO detected in kitchens, or between the carhoxyhemoglobin saturation and the passing of time after exposure to briquet gas. No difference of carboxyhemoglobin saturation was detected between smokers and non-smokers, and the degrees of smoking; only, significant negative correlation was found between the passing of time after smoking and the carboxyhemoglobin saturation. It is ture that air pollution causes or aggravates the respiratory diseases, increases the carboxyhemoglobin saturation in the blood, but what seems to be more hazardous to the health is the air polluted by the briquet gas in the kitchens and on-dol rooms rather than the atmospheric air pollution.

• Clean Technology
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• v.27 no.4
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• pp.332-340
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• 2021

With the recent reinforcement of emission standards, it is necessary to make efforts to reduce NOx from air pollutant-emitting workplaces. The NOx reduction method mainly used in industrial facilities is selective catalytic reduction (SCR), and the most commercial SCR catalyst is the ceramic honeycomb catalyst. This study was carried out to reduce the NOx emitted from steel plants by applying De-NOx catalyst coated on metallic monolith. The De-NOx catalyst was synthesized through the optimized coating technique, and the coated catalyst was uniformly and strongly adhered onto the surface of the metallic monolith according to the air jet erosion and bending test. Due to the good thermal conductivity of metallic monolith, the De-NOx catalyst coated on metallic monolith showed good De-NOx efficiency at low temperatures (200 ~ 250 ℃). In addition, the optimal amount of catalyst coating on the metallic monolith surface was confirmed for the design of an economical catalyst. Based on these results, the De-NOx catalyst of commercial grade size was tested in a semi-pilot De-NOx performance facility under a simulated gas similar to the exhaust gas emitted from a steel plant. Even at a low temperature (200 ℃), it showed excellent performance satisfying the emission standard (less than 60 ppm). Therefore, the De-NOx catalyst coated metallic monolith has good physical and chemical properties and showed a good De-NOx efficiency even with the minimum amount of catalyst. Additionally, it was possible to compact and downsize the SCR reactor through the application of a high-density cell. Therefore, we suggest that the proposed De-NOx catalyst coated metallic monolith may be a good alternative De-NOx catalyst for industrial uses such as steel plants, thermal power plants, incineration plants ships, and construction machinery.

• Analytical Science and Technology
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• v.18 no.2
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• pp.139-146
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• 2005

Removal of NO contained in automobile exhaust gas was accomplished by the non-selective catalyst reduction method. The catalysts were prepared through loading of a specific amount of Ag into ${\gamma}-Al_2O_3$. The conversion of $NO_x$ was studied by varying the temperatures, $O_2$ concentrations and $SO_2$ concentrations for the prepared catalysts. The influence of the structure of catalyst to $NO_x$ conversion was followed through the analysis of the physical properties of the prepared catalysts. Experiments were conducted on each of the catalysts by varying the reaction conditions to find an optimum condition. The catalyst $Ag/{\gamma}-Al_2O_3$ shows a highest $NO_x$ conversion when the Ag content was 2 wt% and a reaction temperature of about $450^{\circ}C$. and after conducting the experiments, samples of before and after experiments analyzed using XRD, XPS, TPR, and UV-Vis DRS experiments. The result indicated that when Ag oxide content could not be maintained well at high temperatures $NO_x$ conversion decreased.