• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.6
• /
• pp.1092-1099
• /
• 2022

Research on exhaust aftertreatment devices to reduce air pollutants and greenhouse gas emissions is being actively conducted. However, in the case of the particulate matters/nitrogen oxides (PM/NOx) simultaneous reduction device for ships, the problem of back pressure on the diesel engine and replacement of the filter carrier is occurring. In this study, for the optimal design of the integrated device that can simultaneously reduce PM/NOx, an appropriate standard was presented by studying the flow inside the device and change in back pressure through the inlet/outlet pressure. Ansys Fluent was used to apply porous media conditions to a diesel particulate filter (DPF) and selective catalytic reduction (SCR) by setting porosity to 30%, 40%, 50%, 60%, and 70%. In addition, the ef ect on back pressure was analyzed by applying the inlet velocity according to the engine load to 7.4 m/s, 10.3 m/s, 13.1 m/s, and 26.2 m/s as boundary conditions. As a result of a computational fluid dynamics analysis, the rate of change for back pressure by changing the inlet velocity was greater than when inlet temperature was changed, and the maximum rate of change was 27.4 mbar. This was evaluated as a suitable device for ships of 1800kW because the back pressure in all boundary conditions did not exceed the classification standard of 68mbar.

• Journal of Bio-Environment Control
• /
• v.31 no.4
• /
• pp.476-484
• /
• 2022

This study was conducted to investigate the effect of closed cultivation and open cultivation method and substrate type on the nutrient ion change pattern and growth of sweet pepper (Capsicum annuum L.) 'Scirocco' according to the reuse of drainage in hydroponics. The sowing, transplanting, and application of the closed and open cultivation method were carried out on August 19 and September 16, and October 21, 2021, respectively. As a result of the analysis of nutrients in the drainage, Na⁺ and Cl^- are representative ions that crops do not absorb properly, and as the growth progresses, they are accumulated in the closed method. In addition, since the content of NH₄-N in the drainage is significantly lower than that of NO₃-N, it is thought that NH₄-N is preferentially absorbed rather than NO₃-N due to the ion selectivity of sweet pepper. The growth and fruit characteristics of sweet pepper did not differ significantly between treatments according to the drainage reuse and the type of substrate. In conclusion, if you take care of poor fruiting due to the weakening of power after the middle period in hydroponic cultivation of sweet pepper according to the cultivation method of closed and open, and the substrate type of coir and rock wool, the difference between treatments is not large, so the sweet pepper can be produced by selecting the cultivation methods and substrate types suitable for the conditions of grower. However, as interest in environmental pollution has recently increased, it is judged that there is no need to worry about a decrease in quantity or quality, even if a closed cultivation method is adopted under the assumption that pathogen infection due to drainage reuse is well managed. It is expected that if coir is applied instead of rock wool, which causes a problem of disposal, it will further contribute to the reduction of environmental pollution.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.25 no.1
• /
• pp.133-149
• /
• 2022

Existing domestic studies on estimating rice yield were mainly implemented at the level of cities and counties in the entire nation using MODIS satellite images with low spatial resolution. Unlike previous studies, this study tried to estimate rice yield at the level of eup-myon-dong in Gimje-si, Jeollabuk-do using Sentinel-2 satellite images with medium spatial resolution, rainfall and soil data, and then to evaluate its accuracy. Five vegetation indices such as NDVI, LAI, EVI2, MCARI1 and MCARI2 derived from Sentinel-2 images of August 1, 2018 for Gimje-si, Jeollabuk-do, rainfall and paddy soil-type data were aggregated by the level of eup-myon-dong and then rice yield was estimated with gamma generalized linear model, an expanded variant of multi-variate regression analysis to solve the non-normality problem of dependent variable. In the rice yield model finally developed, EVI2, rainfall days in September, and saline soils ratio were used as significant independent variables. The coefficient of determination representing the model fit was 0.68 and the RMSE for showing the model accuracy was 62.29kg/10a. This model estimated the total rice production in Gimje-si in 2018 to be 96,914.6M/T, which was very close to 94,470.3M/T the actual amount specified in the Statistical Yearbook with an error of 0.46%. Also, the rice production per unit area of Gimje-si was amounted to 552kg/10a, which was almost consistent with 550kg/10a of the statistical data. This result is similar to that of the previous studies and it demonstrated that the rice yield can be estimated using Sentinel-2 satellite images at the level of cities and counties or smaller districts in Korea.

• Environmental and Resource Economics Review
• /
• v.31 no.2
• /
• pp.165-204
• /
• 2022

This study organized data from 2000 to 2014 for 20 grid-connected countries in Europe and analyzed the determinants of carbon emissions through the panel GLS method considering the problem of heteroscedasticity and autocorrelation. At the same time, the effect of introducing ETS was considered by dividing the sample period as of 2005 when the European emission trading system was introduced. Carbon emissions from individual countries were used as dependent variables, and proportion of generation by each source, power self-sufficiency ratio of neighboring countries, power production from resource-holding countries, concentration of power sources, total energy consumption per capita in the industrial sector, tax of electricity, net electricity export per capita, and size of national territory per capita. According to the estimation results, the proportion of nuclear power and renewable energy generation, concentration of power sources, and size of the national territory area per capita had a negative (-) effect on carbon emissions both before and after 2005. On the other hand, the proportion of coal power generation, the power supply and demand rate of neighboring countries, the power production of resource-holding countries, and the total energy consumption per capita in the industrial sector were found to have a positive (+) effect on carbon emissions. In addition, the proportion of gas generation had a negative (-) effect on carbon emissions, and tax of electricity were found to have a positive (+) effect. However, all of these were only significant before 2005. It was found that net electricity export per capita had a negative (-) effect on carbon emissions only after 2005. The results of this study suggest macroscopic strategies to reduce carbon emissions to green growth, suggesting mid- to long-term power mix optimization measures considering the electricity trade market and their role.

• Economic and Environmental Geology
• /
• v.56 no.4
• /
• pp.457-473
• /
• 2023

Asbestos has been produced, imported and used in various industries in Korea over the past decades. Since asbestos causes fatal diseases such as malignant mesothelioma and lung cancer, the use of asbestos has been generally banned in Korea since 2009. However, there are still many asbestos-containing materials around us, and safe management is urgently needed. This study aims to examine asbestos-related trend changes using major asbestos-related keywords based on the asbestos trend analysis using big data for the past 32 years (1991 to 2022) in Korea. In addition, we reviewed both domestic trends related to the production, import, and use of asbestos before 1990 and asbestos-related policies from 2023 to 2027. From 1991 to 2000, main keywords related to asbestos were research, workers, carcinogens, and the environment because the carcinogenicity of asbestos was highlighted due to domestic production, import, and use of asbestos. From 2001 to 2010, the main keywords related to asbestos were lung cancer, litigation, carcinogens, exposure, and companies because lawsuits were initiated in the US and Japan in relation to carcinogenicity due to asbestos. From 2011 to 2020, the high ranking keywords related to asbestos were carcinogen, baseball field, school, slate, building, and abandoned asbestos mine due to the seriousness of the asbestos problem in Korea. From 2021 to present (2023), the main search keywords related to asbestos such as school, slate (asbestos cement), buildings, landscape stone, environmental impact assessment, apartment, and cement appeared.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.49 no.3
• /
• pp.247-258
• /
• 2023

This study aims to investigate the enhancement of water resistance and improvement in adhesion to the skin by combining dextrin palmitate and isopropyl titanium triisostearate coating materials with titanium dioxide. Due to the recent increase in consumers who enjoy outdoor activities, the demand for sunscreen with excellent water resistance is increasing. Prior research was conducted with O/W, Pickering, and W/O/W multiple formulations, but there was a limit to water resistance. The purpose of this study is to develop a complex inorganic powder that can improve water resistance and increase adhesion to the skin to solve this problem. First, we combined dextrin palmitate and isopropyl titanium triisostearate coating materials to form a composite with titanium dioxide. The coating of the inorganic powder was confirmed using FE-SEM and FT-IR analysis. The composite exhibited significantly higher in vitro water resistance compared to other formulations. The hydrophobicity of the coated inorganic powder was compared by measuring the contact angles. When the coated inorganic powder was applied to the W/O sunscreen formulation and the non-coated inorganic powder was applied to the W/O sunscreen formulation as a control, the SPF of the sunscreen containing the coated inorganic powder was higher. These results were the same when observed with a UV camera. Finally the adhesion of the coated inorganic powder to the skin was assessed by applying it to a foundation product. In vivo study, it was observed that the product formulated with the coated powder exhibited less smudging compared to the foundation product formulated with the non-coated powder. The developed inorganic powder in this study demonstrated excellent adhesion to the skin, providing a superior sensory experience, as well as enhanced hydrophobicity and remarkable water resistance effects. In the future, the result of this study is expected to help develop various sunscreen products to improve water resistance.

• Knowledge Management Research
• /
• v.23 no.4
• /
• pp.91-112
• /
• 2022

In order to improve the quality of consumption in senior generation, it is necessary to build trust in the digital consumption environment. However, there are limitations from previous researches on consumption in the digital environment that has mainly focused on Millennial and Z generations. Therefore, this study aims to examine the antecedents of digital consumption trust and to explore the market segments of senior generation created by the dynamics of these antecedents. In addition, in order to provide practical implications, we investigate the difference in the level of perceived digital consumption trust using segmentation. This study, therefore, used 2021 Korea's consumer life index data conducted by the Korea Consumer Agency for general consumers, and only consumer data of 60s and older are extracted for the analysis. As a result, we confirm from the main results that the three antecedents, consumer competency, perceived corporate responsibility, and local community's problem-solving environment, are significant in building the digital consumption trust in the senior generation. It is academically significant in this aspect to look at approaches to improve senior customers' trust in digital consumption circumstances by dividing generations because generations exhibit varying levels of understanding of online consumption or digital consumption conditions. It is academically significant in this aspect to look at approaches to improve senior customers' trust in digital consumption circumstances by dividing generations because generations exhibit varying levels of understanding of online consumption or digital consumption conditions. Additionally, it is proposed as a practical implication that it should be managed so that significant improvements of customers, businesses, and regional public institutions are developed in order to allow the senior consumers to prepare trusted digital consumption circumstances.

• Journal of the Korean Orthopaedic Association
• /
• v.52 no.1
• /
• pp.1-6
• /
• 2017

Purpose: To retrospectively compare minimally invasive percutaneous plate osteosynthesis (MIPPO) with open plate fixation for the treatment of clavicle midshaft fracture. Materials and Methods: Between November 2011 to May 2014, 40 cases that were followed for more than 1 year-among all cases of MIPPO and open plate fixation-were analyzed. The study population was divided into two groups: group A included 20 cases of MIPPO and group B included 20 open plate fixation cases. The comparative analysis between the two groups was based on the operative time, bone union, functional evaluation (American Shoulder and Elbow Society score), incision length, pain relief (visual analogue scale, VAS), and complication. Results: The bone union was successful for all the cases, and the functional evaluation scores of the shoulder joint were satisfactory for both groups (p>0.05). The operative time was 47.5 minutes and 58.7 minutes for group A and B, respectively (p<0.05). The incision length for group A was 6.2 cm and that for group B was 10.7 cm with statistical significance (p<0.05). Pain relief (VAS) after surgery for group A showed a quick recuperation in the early stages. For complications, there were 2 cases of dysesthesia and 1 case of malunion due to metal fixation failure in group A. There were 6 cases of dysesthesia and 2 cases of cosmetic problem due to hypertrophic scar in group B. Conclusion: Surgical results of clavicle shaft fracture were satisfactory for both groups, but group A had advantages of shorter operative time, minimal incision length, and better pain relief in the early stages compared with group B. However, we need further evaluations with long-term follow-up results and complications, such as malunion and exposure on radiation.

• Analytical Science and Technology
• /
• v.21 no.6
• /
• pp.487-494
• /
• 2008

An experiment was performed for zone refined Re-filament and normal (nonzone refined) Re-filament to reduce the background effect on the measurement of low level uranium samples. From both filaments, the signals which seemed to come from a cluster of light alkali elements, $(^{39}K_6)^+$, $(^{39}K_5+^{41}K)^+$ and $PbO_2$ were identified as the isobaric effect of the uranium isotopes. The isobaric effect signal was completely disappeared by heating the filament about $2000^{\circ}C$ at < $10^{-7}$ torr of vacuum for more than 1.5 hour in zone refined Refilaments, while that from the normal Re-filaments was not disappeared completely and was still remained as 3 pg. of uranium as the impurities after the degassing treatment was performed for more than 5 hours at the same condition of zone refined filaments. A threshold condition eliminating impurities were proved to be at 5 A and 30 minutes of degassing time. The uranium content as an impurity in rhenium filament was checked with a filament degassing treatment using the U-233 spike by isotope dilution mass spectrometry. A 0.31 ng of U was detected in rhenium filament without degassing, while only 3 pg of U was detected with baking treatment at a current of 5.5 A for 1 hr. Using normal Re-filaments for the ultra trace of uranium sample analysis had something problem because uranium remains to be 3 pg on the filament even though degassed for long hours. If the 1 ng uranium were measured, 0.3% error occurred basically. It was also conformed that ionization filament current was recommended not to be increased over 5.5 A to reduce the background. Finally, the contents of uranium isotopes in uranium standard materials (KRISS standard material and NIST standard materials, U-005 and U-030) were measured and compared with certified values. The differences between them showed 0.04% for U-235, 2% for U-234 and 2% for U-236, respectively.

• The Journal of Korean Academy of Prosthodontics
• /
• v.61 no.3
• /
• pp.204-214
• /
• 2023

The occlusal treatment including prosthetic treatment should be considered when the pathologic symptom was observed with the excessive discrepancy between the centric relation occlusion (CRO) and the maximum intercuspal position (MIP). Through careful diagnosis, the malocclusion and interarch relationship can be analyzed, and occlusal adjustment, restorative treatment, orthodontic therapy, or orthognathic surgery can be performed depending on the degree of disharmony. The patient in this case report complained the unstable occlusion and loss of masticatory function that had been occurring for several years. At the time of the visit, the patient showed severe occlusal disharmony, with only the upper right second molar contacting the lower jaw at the maximum intercuspal position. Based on the analysis of the occlusion, it was difficult to solve the problem with just occlusal adjustment or restorative treatment. In addition, the patient had the skeletal class II malocclusion between the upper and lower jaws. Therefore, for resolving the severe skeletal class II malocclusion, pre- and post-orthodontic treatment, bilateral sagittal split ramus osteotomy (BSSRO) was performed. After that, the occlusal adjustment was performed for stable occlusion, and the missing teeth area was restored with dental implants. During the follow-up period, a periodic follow-up visits and additional occlusal adjustments were performed to achieve a stable centric occlusion and harmonious anterior and lateral guidance. As a result, the final prosthodontic treatment was completed, and the patient's masticatory function was restored.