Doo Chan Choi;Min Hyeok Yang;MIn Hyeok Ko;Su Min Oh
Journal of the Society of Disaster Information
/
v.20
no.1
/
pp.40-46
/
2024
Purpose: In this study, in order to ensure the evacuation safety of plant facilities, we analyze the relationship between the height of smoke removal boundary walls, the presence or absence of smoke removal equipment, and evacuation safety. Method: Using fire and evacuation simulations, evacuation safety was analyzed through changes in the height of the smoke removal boundary wall, air supply volume and exhaust volume according to vertical dista. Result: In the case of visible drawings, if only 0.6m of boundary wall is used, the time below 5m reaches the shortest, and 1.2m of boundary width is 20% longer than when using smoke removal facilities. In the case of temperature, 1.2m is 20% longer than 0.6m when only the boundary width is used without smoke removal facilities. Conclusion: It was found that increasing the length of the smoke removal boundary wall could affect visibility, and installing a smoke removal facility would affect temperature. Therefore, it is determined that an appropriate smoke removal plan and smoke removal equipment should be installed in consideration of the process characteristics.
Nanoplastics (NP) exhibit distinct material properties compared to microplastics (MP), necessitating their separate recognition. Review of research outcomes and policy documents on NP reveals that most policy frameworks predominantly define MPs as solid synthetic polymer materials measuring 5 mm or less, but do not distinguish them from NP. However, recent revisions in regulations by the EU classify NPs as particles that range in size from 1 to 1,000 nm, as confirmed by some academic studies. Research on NPs often relies on experimental investigations centered around water systems, with a focus on high-concentration experimental conditions using spherical polystyrene-based NPs in behavior and impact studies. Notably, the environmental behavior characteristics of NP show differences in influence depending on the NP type, emphasizing the need for field simulation research. These challenges are mirrored in Korean society, so it is necessary to redefine NP to be distinct from MP in both research and policy. This study aimed to assess the current state of NP management globally and domestically and highlight policy considerations and issues in the existing response to NP. Upon comprehensive review, it becomes apparent that reaching an international agreement on MP faces methodological limitations, which could potentially burden efforts to precisely define NP size. Therefore, referencing the EU's recent regulatory revisions is crucial in domestic policy. Specific adjustments should commence from the MP concept through insights from the domestic industry, guidance from the academic community, and thorough discussions to ensure social acceptance.
Seong Min Lee;Ha Young Kim;Byeol Kim;Kwang Il Hwang
Journal of the Korean Society of Marine Environment & Safety
/
v.30
no.2
/
pp.165-175
/
2024
Hydrogen is being touted as one of the energy sources to combat the climate change crisis. However, hydrogen can leak into enclosed spaces, rise to the ceiling, accumulate, and cause fires and explosions if it encounters an ignition source. In particular, ships that transport hydrogen or use it as a fuel comprise multiple enclosed spaces. Therefore, the dif usion characteristics within these spaces must be understood to ensure the safe use of hydrogen. The purpose of this study is to experimentally determine the diffusion characteristics of helium, which has similar properties to hydrogen, in a closed space on board a ship, and to determine the change in the oxygen concentration along the leakage direction as the air change per hour(ACH) increases to 25, 30, 35, 40, and 45 through CFD simulation. The study, results revealed that the oxygen concentration reduction rate was 2% for leakage in the -z direction and 1% for leakage in the +x and +z directions, and the ventilation time was 15 min 30 s for leakage in the -z direction, 7 min for leakage in the +x direction, and 9 min for leakage in the +z direction, showing that differences existed in the oxygen concentration and ventilation time depending on the leakage direction. In addition, no significant difference was observed in the rate of oxygen concentration reduction and ventilation time in all leakage directions from the ACH of 35 and above in the experimental space. Therefore, because the oxygen concentration and ventilation time were not improved by increasing the ACH, 35 was noted as the optimal ACH in this experimental environment.
One of the key factors in research regarding long-distance laser beam propagation, as in free-space optical communication or laser power transmission, is the transmission efficiency of the laser beam. As a way to improve efficiency, we perform extensive numerical simulations of the effect of modifying the laser beam's profile, especially replacing the fundamental Gaussian beam with a super-Gaussian beam. Numerical simulations of the transmitted power in the ideal diffraction-limited beam diameter determined by the optical system of the transmitter, after about 1-km propagation, reveal that the second-order super-Gaussian beam can yield superior performance to that of the fundamental Gaussian beam, in both single-channel and coherently combined multi-channel laser transmitters. The improvement of the transmission efficiency for a 1-km propagation distance when using a second-order super-Gaussian beam, in comparison with a fundamental Gaussian beam, is estimated at over 1.2% in the singlechannel laser transmitter, and over 4.2% and over 4.6% in coherently combined 3- and 7-channel laser transmitters, respectively. For a range of the propagation distance varying from 750 to 1,250 m, the improvement in transmission efficiency by use of the second-order super-Gaussian beam is estimated at over 1.2% in the single-channel laser transmitter, and over 4.1% and over 4.0% in the coherently combined 3- and 7-channel laser transmitters, respectively. These simulation results will pave the way for future advances in the generation of higher-order super-Gaussian beams and the development of long-distance optical energy-transfer technology.
Hassan Ali Al-Ababneh;Ainur Osmonova;Ilona Dumanska;Petro Matkovskyi;Andriy Kalynovskyy
International Journal of Computer Science & Network Security
/
v.24
no.7
/
pp.128-142
/
2024
Creation and implementation of export-oriented strategy is an urgent issue of economic development of any country. In an export-oriented model of economic development, exports should be a means of promoting economic growth and a tool to strengthen existing and potential competitive advantages. Agricultural production is the key factor in exports and the source of foreign exchange earnings in many countries. However, the export potential of agricultural producers may be inefficiently fulfilled due to the heterogeneity of countries in terms of economic development, trade relations and border policy. The aim of the research is to study the nature, main trends and problematic aspects of fulfilling the export potential of agricultural production in the context of aggravating food crisis. The study involved general scientific methods (induction and deduction, description, analysis, synthesis, generalization) and special (statistical method, economic analysis, descriptive statistics and interstate comparisons, graphical method). The need to ensure food security by countries around the world urges the importance of the agricultural sector as a catalyst for economic development, sources of foreign exchange earnings, investment direction, etc. The study of agricultural specialization led to the conclusion that wheat and sugar are goods with the highest export potential. It is substantiated that the countries of South America, OECD, North America and Europe have the highest level of realization of export potential of agricultural production, and African countries are import-dependent. In addition, the low export orientation of Africa and Asia due to the peculiarities of their natural and climatic conditions is established based on the assessment of export-import operations in the regional context. The internal and external export potential of each of the regions is analysed. Economic and mathematical simulation of assessing the impact of the most important factors on the wheat exports volumes was applied, which allowed predicting wheat exports volume and making sound management decisions regarding the realization of the export potential of agricultural companies. The inverse correlation between the exports volume and wheat consumption per capita, and the direct correlation between the effective size and area of land used for wheat cultivation was established through the correlation and regression analysis.
Lee, Ji Hyun;Lee, Dong Woog;Gyu, Jang Se;Kwak, No-Sang;Lee, In Young;Jang, Kyung Ryoung;Choi, Jong-shin;Shim, Jae-Goo
Korean Chemical Engineering Research
/
v.53
no.5
/
pp.590-596
/
2015
Estimating potential of $CO_2$ emission reduction of non-capture $CO_2$ utilization (NCCU) technology was evaluated. NCCU is sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue gas. For the estimating the $CO_2$ emission reduction, process simulation using process simulator (PRO/II) based on a chemical plant which could handle $CO_2$ of 100 tons per day was performed, Also for the estimation of the indirect $CO_2$ reduction, the solvay process which is a conventional technology for the production of sodium carbonate/sodium bicarbonate, was studied. The results of the analysis showed that in case of the solvay process, overall $CO_2$ emission was estimated as 48,862 ton per year based on the energy consumption for the production of $NaHCO_3$ ($7.4GJ/tNaHCO_3$). While for the NCCU technology, the direct $CO_2$ reduction through the $CO_2$ carbonation was estimated as 36,500 ton per year and the indirect $CO_2$ reduction through the lower energy consumption was 46,885 ton per year which lead to 83,385 ton per year in total. From these results, it could be concluded that sodium bicarbonate production technology through the carbonation reaction of $CO_2$ contained in the flue was energy efficient and could be one of the promising technology for the low $CO_2$ emission technology.
Park, Sang Hyun;Kim, Joo Cheol;Jeong, Dong Kug;Jung, Kwan Sue
KSCE Journal of Civil and Environmental Engineering Research
/
v.33
no.6
/
pp.2255-2265
/
2013
This study presents the width function-based Clark model. To this end, rescaled width function with distinction between hillslope and channel velocity is used as time-area curve and then it is routed through linear storage within the framework of not finite difference scheme used in original Clark model but analytical expression of linear storage routing. There are three parameters focused in this study: storage coefficient, hillslope velocity and channel velocity. SCE-UA, one of the popular global optimization methods, is applied to estimate them. The shapes of resulting IUHs from this study are evaluated in terms of the three statistical moments of hydrologic response functions: mean, variance and the third moment about the center of IUH. The correlation coefficients to the three statistical moments simulated in this study against these of observed hydrographs were estimated at 0.995 for the mean, 0.993 for the variance and 0.983 for the third moment about the center of IUH. The shape of resulting IUHs from this study give rise to satisfactory simulation results in terms of the mean and variance. But the third moment about the center of IUH tend to be overestimated. Clark model proposed in this study is superior to the one only taking into account mean and variance of IUH with respect to skewness, peak discharge and peak time of runoff hydrograph. From this result it is confirmed that the method suggested in this study is useful tool to reflect the heterogeneity of drainage path and hydrodynamic parameters. The variation of statistical moments of IUH are mainly influenced by storage coefficient and in turn the effect of channel velocity is greater than the one of hillslope velocity. Therefore storage coefficient and channel velocity are the crucial factors in shaping the form of IUH and should be considered carefully to apply Clark model proposed in this study.
This study was carried out to research the multimedia fate modeling, concentration distribution and impact assessment of polycyclic aromatic hydrocarbons (PAHs) emitted from automobiles, which are known as carcinogenic and mutation chemicals. The amount of emissions of PAHs was determined based on the census data of automobiles at a target S-city and emission factors of PAHs, where multimedia fugacity modeling was conducted by the restriction of PAHs transfer between air-soil at the impervious area. PAHs' Concentrations and their distributions at several environmental media were predicted by multimedia fugacity model (level III). The residual amounts and the distributions of PAHs through mass transfer of PAHs between environment media were used to assess the health risk of PAHs at unsteady state (level IV), where the sensitivity analyses of the model parameter of each variable were conducted based on Monte Carlo simulation. The experimental result at S-city showed that Fluoranthene among PAHs substances are the highest residual concentrations (60%, 53%, 32% and 34%) at all mediums (atmospheric, water, soil, sediment), respectively, where most of the PAHs were highly accumulated in the sediment media (more than 80%). A result of PAHs concentration changes in S-city over the past 34 years identified that PAHs emissions from all environmental media increased from 1983 to 2005 and decreased until 2016, where the emission of heavy-duty vehicle including truck revealed the largest contribution to the automotive emissions of PAHs at all environment media. The PAHs concentrations in soil and water for the last 34 years showed the less value than the legal standards of PAHs, but the PAHs in air exceeded the air quality standards from 1996 to 2016. The result of this study is expected to contribute the effective management and monitoring of toxic chemicals of PAHs at various environment media of Metropolitan city.
Kim, Ki-Deog;Suh, Jong-Taek;Lee, Jong-Nam;Yoo, Dong-Lim;Kwon, Min;Hong, Soon-Choon
Horticultural Science & Technology
/
v.33
no.6
/
pp.911-922
/
2015
This study was carried out to evaluate growth characteristics of Kimchi cabbage cultivated in various highland areas, and to create a predicting model for the production of highland Kimchi cabbage based on the growth parameters and climatic elements. Regression model for the estimation of head weight was designed with non-destructive measured growth variables (NDGV) such as leaf length (LL), leaf width (LW), head height (HH), head width (HW), and growing degree days (GDD), which was $y=6897.5-3.57{\times}GDD-136{\times}LW+116{\times}PH+155{\times}HH-423{\times}HW+0.28{\times}HH{\times}HW{\times}HW$, ($r^2=0.989$), and was improved by using compensation terms such as the ratio (LW estimated with GDD/measured LW ), leaf growth rate by soil moisture, and relative growth rate of leaf during drought period. In addition, we proposed Excel spreadsheet model for simulation of yield prediction of highland Kimchi cabbage. This Excel spreadsheet was composed four different sheets; growth data sheet measured at famer's field, daily average temperature data sheet for calculating GDD, soil moisture content data sheet for evaluating the soil water effect on leaf growth, and equation sheet for simulating the estimation of production. This Excel spreadsheet model can be practically used for predicting the production of highland Kimchi cabbage, which was calculated by (acreage of cultivation) ${\times}$ (number of plants) ${\times}$ (head weight estimated with growth variables and GDD) ${\times}$ (compensation terms derived relationship of GDD and growth by soil moisture) ${\times}$ (marketable head rate).
Kim, So Won;Son, Yeong Mo;Kim, Eun Sook;Park, Hyun
Journal of Korean Society of Forest Science
/
v.103
no.3
/
pp.446-452
/
2014
This research aimed to provide a method to estimate growing stock and carbon stock using the characteristics of forest type map such as the age-class, DBH class and crown density class. We transformed the growing stock data of national forest inventory (mainly Kangwon-do province) onto those of time when the forest type map was established. We developed a simulation model for the growing stock using the transformed data and the characteristics of forest type map by the quantification method I. By comparing partial correlation coefficient, we found that quantification of growing stock was largely affected by age-class followed by crown density class, forest type and DBH class. The growing stock, was estimated as minimum in the broadleaved forest with age-class II, DBH class 'Small', and crown density class 'Low' as $20.0m^3/ha$, whereas showed maximum value in the coniferous forest with age-class VI, DBH class 'Large', and crown density class 'High' as $305.0m^3/ha$. The growing stock for coniferous, broadleaved, and mixed forest were estimated as $30.5{\sim}305.0m^3/ha$, $20.0{\sim}200.4m^3/ha$, and $23.8{\sim}238.1m^3/ha$, respectively. When we compared the carbon stock by forest type, the carbon stock by age class based on growing stock was maximum when DBH class was 'Large' and crown density class was 'High' regardless of forest type. This estimation of growing stock by using characteristic of forest type can be used to estimate the changes in growing stock and carbon stock resulting from deforestation or natural disaster. In addition, we hope it provide a useful advice when forest officials and policy makers have to make decisions in regard to forest management.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.