• 한국폐기물자원순환학회지
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• 제34권5호
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• pp.518-527
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• 2017

The development of renewable energy is currently strongly required to address environmental problems such as global warming. In particular, biomass is highlighted due to its advantages. When using biomass as an energy source, the conversion process is essential. Fast pyrolysis, which is a thermochemical conversion method, is a known method of producing bio-oil. Therefore, various studies were conducted with fast pyrolysis. Most studies were conducted under a lab-scale process. Hence, scaling up is required for commercialization. However, it is difficult to find studies that address the process analysis, even though this is essential for developing a scaled-up plant. Hence, the present study carries out the process analysis of biomass pyrolysis. The fast pyrolysis system includes a biomass feeder, fast pyrolyzer, cyclone, condenser, and electrostatic precipitator (ESP). A two-stage, semi-global reaction mechanism was applied to simulate the fast pyrolysis reaction and a circulating fluidized bed reactor was selected as the fast pyrolyzer. All the equipment in the process was modeled based on heat and mass balance equations. In this study, process analysis was conducted with various reaction temperatures and residence times. The two-stage, semi-global reaction mechanism for circulating fluidized-bed reactor can be applied to simulate a scaled-up plant.

• 대한수학회지
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• 제57권1호
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• pp.249-281
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• 2020

A reaction-diffusion model with spatiotemporal delay modeling the dynamical behavior of a single species is investigated. The parameter regions for the local stability, global stability and instability of the unique positive constant steady state solution are derived. The conditions of the occurrence of Turing (diffusion-driven) instability are obtained. The existence of time-periodic solutions, the existence and nonexistence of nonconstant positive steady state solutions are proved by bifurcation method and energy method. Numerical simulations are presented to verify and illustrate the theoretical results.

• 대한건축학회논문집:계획계
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• 제35권6호
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• pp.81-92
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• 2019

Globalization has diversified ethnic composition thus increased the risk of conflicts and socio-political instability in global cities. However, still the status of community facility in a global city is unclear despite its critical role to build sustainable community in global era. In Seoul, as a reaction of globalization, 19 community facilities known as the 'Seoul Global Center' have been established since 2007 by Seoul Metropolitan Government. These facilities have started to provide basic foreigner services but been transformed to foreigner service hub with multiple functions in terms of a living, a business, a labour, etc. This study explores the role of the community facility for foreigners by using the Seoul Global Center as a case study, conducting a site observation, an interview(13 staff) and a questionnaire(148 visitors). The findings are the community facility functions as a 'global platform' in forms of a policy tool for implementing the urban globalization strategy, a mediator connecting foreign migrants with local communities, an applicant for successful settlement of foreign residents, an incubator that grows human and social capital, and a base for collecting and aggregating information on foreign migrants and forming new local identities.

• East Asian Economic Review
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• 제18권2호
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• pp.187-212
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• 2014

The purpose of this paper is to examine the equity market crisis contagion in major Asian economic markets. A comparative assessment of Asian markets during the Asian Financial Crisis and Global Financial crisis may clearly identify the changing nature of long term integration of major Asian markets. The selection criteria of specific Asian markets of different peripheries depend particularly on the roles and structure of these markets. The impact of the global financial contagion and the lingering financial linkage in the aftermath of crisis will explain the reaction of the majority of Asian markets to global linkage. While majority of the studies focused on dynamic short term association in European and MENA contagions in the post global financial crisis period; after the global financial crisis, attention paid to long term Asian contagion adds new perspective to hitherto disorganized theories.

• 국제지역연구
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• 제22권4호
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• pp.3-18
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• 2018

본 연구에서는 변동성반응가설에 입각한 T-GARCH 모형을 사용하여 최근 24년간의 일별 주식시장 수익률 자료를 바탕으로 OECD 29개 회원국들의 자본시장 충격반응도를 분석하였다. 연구모형에 사용한 독립변수로는 글로벌 금융위기의 진원지이며 세계시장 점유율도 가장 큰 미국시장 수익률을 사용하였다. 그 결과 OECD 회원국 중 미국으로부터의 수익률 전이효과가 가장 큰 나라는 프랑스, 핀란드, 멕시코의 순으로 나타났고 모형의 설명력은 캐나다, 멕시코, 프랑스 순으로 나타났다. 변동성반응가설에 입각한 충격반응의 크기로는 독일, 칠레, 스위스, 덴마크의 순으로 크게 나타났고 하락시장 충격에 대한 반응은 그리스, 영국, 호주, 일본의 순으로 크게 나타났다. NAFTA에 속한 캐나다와 멕시코는 예상대로 미국시장으로부터의 수익률 전이와 설명력이 크게 나타났으나 충격반응의 정도는 OECD 회원국들 중 하위권에 속하는 것으로 나타나 인근 지역의 국가들간의 더 큰 영향력이 존재한다는 중력이론을 지지하지 않았다. 한편, 2008년 미국발 글로벌 금융위기기간만을 고려한 소표본 분석을 통해서는 전체 기간과는 달리 북미 3국의 충격반응도가 서로 일관성이 없는 대신 유럽 각국의 충격반응도는 더욱 강하게 나타남으로써 미국발 충격이 주로 유럽지역에 미쳤음을 입증해 주었다.

• Nuclear Engineering and Technology
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• 제31권6호
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• pp.595-607
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• 1999

The reaction cross-sections of $^{nat}$Ti(p,X)$^{48}$ V, $^{nat}$Fe(p,X)$^{56}$ Co, $^{nat}$Cu(p,X)$^{65}$ Zn and $^{nat}$Mo(p,X)$^{96}$ Tc for TLA application are calculated in the frame of the ECIS-GNASH code system up to 60 MeV. The calculated results are compared with the experimental data taken from the EXFOR at the NEA Data Bank. A preliminary calculation with the global optical parameters of Varner et al. shows considerable differences from the experimental data at low energy range. The global optical parameters for the imaginary volume potential and the diffuseness of the imaginary potential are adjusted to achieve a better description of the experimental data in the vicinities of peak position below 16 MeV. 16 MeV.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 춘계 학술대회논문집
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• pp.35-40
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• 2002

The dynamic behaviors of the single vortex in a reacting and non-reacting methane-air jet flow were investigated numerically. The numerical method was based on a predictor-corrector for low Mach number flow A two-step global reaction mechanism was adopted as a combustion model. After fuel and air were developed entirely in computational domain, the single vortex was generated by an axisymmetric jet that was impulsed to emit a cold fuel. Through comparisons of single vortex in reacting and non-reacting jet flow, it was found that global dynamic behaviors and the mechanisms leading to the formation, transport processes of vortex ring were influenced significantly by heat release from reaction. In addition, the interaction between a single vortex and flame bulge generated by buoyance effect in a reacting jet flow was found.

• Asian Journal of Atmospheric Environment
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• 제5권1호
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• pp.21-28
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• 2011

Occupational nanomaterial exposure is an important issue in the manufacture of such products. People are also exposed to various nanoparticles in their living environments. In this study, we investigated nanoparticle formation during the reaction of ozone and volatile organic compounds (VOCs) emitted from a commercial air freshener, one of many widely used consumer products, in a $1-m^3$ reaction chamber. The air freshener contained various VOCs, particularly terpenes. A petri dish containing 0.5 mL of the air freshener specimen was placed in the bottom of the chamber, and ozone was continuously injected into the center of the chamber at a flow rate of 4 L/min with an ozone concentration of either 50, 100 or 200 ppb. Each test was conducted over a period of about 4 h. The higher ozone concentrations produced larger secondary nanoparticles at a faster rate. The amount of ozone reacted was highly correlated with the amount of aerosol formation. Ratios of reacted ozone concentration and of formed particle mass concentration for the three injected ozone concentrations of 50, 100 and 200 ppb were similar to one other; 4.6 : 1.9 : 1.0 and 4.7 : 2.2 : 1.0 for ozone and aerosol mass, respectively.

• 한국연소학회지
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• 제15권4호
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• pp.1-8
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• 2010

Mild combustion is considered as a promising combustion technology for energy saving and low emission of combustion product gases. In this paper, the controllability of reaction region in mild combustion is examined by using co-axial air nozzle. For this purpose, numerical approach is carried out. Propane is considered for fuel and air is considered for oxidizer and the temperature of air is assumed 900K slightly higher than auto ignition temperature of propane. But unlike main air, the atmospheric condition of co-axial air is considered. Various cases are conducted to verify the characteristics of Co-Axial air burner configuration. The use of coaxial air can affect reaction region. These modification help the mixing between fuel and oxidizer. Then, reaction region is reduced compare to normal burner configuration. The enhancement of main air momentum also affects on temperature uniformity and reaction region. The eddy dissipation concept turbulence/chemistry interaction model is used with two step of global chemical reaction model.

• 한국안전학회지
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• 제34권1호
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• pp.70-75
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• 2019

The aging of society is not only Korea's challenge but also a global issue. This leads to an increase in the number of elderly drivers who are much more prone to major traffic accidents. Therefore, we need a system to test aged drivers' driving abilities. As part of efforts to establish such a system, researchers of KoROAD. have conducted a study on the correlation between aging and driving abilities by analyzing old drivers' reaction time. The study shows that there was a sharp increase in reaction time for drivers aged 65 and over. The current reaction time of 2.5 secs for the 85 percent of eligible drivers needs to be revised upward in aging societies. From now on, we need to come up with the traffic safety measures that can deal with the issue of drivers of old age.