• Title/Summary/Keyword: Local heating

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"Dust, Ice, and Gas In Time" (DIGIT) Herschel Observations of GSS30-IRS1 in Ophiuchus

  • Je, Hyerin;Lee, Jeong-Eun;Green, Joel D.;Evans, Neal J. II
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.63.2-63.2
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    • 2014
  • As a part of the "Dust, Ice, and Gas In Time" (DIGIT) key program on Herschel, we observed GSS30-IRS1, a Class I protostar located in Ophiuchus (d =125 pc), with Herschel/Photodetector Array Camera and Spectrometer (PACS). More than 70 lines were detected within a wavelength range from 50 ${\mu}m$ to 200 ${\mu}m$: CO lines from J = 14-13 to 41-40, several $H_2O$ lines of Eup = 100 K to 1500 K, 16 transitions of OH rotational lines, and two atomic [O I] lines at 63 and 145 ${\mu}m$. The [C II] line, known as a tracer of externally heated gas by the interstellar radiation field, is also detected at 158 ${\mu}m$. All lines, except [O I] and [C II], are detected only at the central spaxel of $9^{\prime\prime}.4{\times}9^{\prime\prime}.4$. The [O I] emission is extended along a NE-SW orientation, which is consistent with the known outflow direction, while the [C II] line is detected over all spaxels. One possible explanation of the detection of the [C II] line and no correlation of its spatial distribution with any other molecular emission is the existence of the enhanced ISRF nearby GSS30-IRS1. One interesting feature of GSS30-IRS1 is that the continuum emission is extended beyond the point-spread function (PSF), unlike the molecular line emission, indicative of significant external heating. The best-fit continuum model of GSS30-IRS1 with the physical structure including flared disk, envelope, and outflow shows that the internal luminosity is 11 $L_{\odot}$, and the region is also externally heated by a radiation field enhanced by a factor of 25 compared to the local standard interstellar field.

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The Novel Configuration of Integrated Network for Building Energy System (빌딩 에너지시스템 통합네트워크 구축에 관한 연구)

  • Hong, Won-Pyo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.10a
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    • pp.229-234
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    • 2008
  • The new millennium has started with several innovations driven by fast evolution of the technologies in energy sector. A strong impulse towards the diffusion of new economical efficient technologies regulatory incentives related to energy production from renewable source and a small scale building trigeneration and to promotion of more sustainable environmental-friendly generation solutions, the evolution of electricity markets, more and more binding local emission constraints, and the need for improving the security of supply to reduce the energy system vulnerability. The 24 percentage energy quantify of total energy consumption consumes in commercial buildings and residential houses and the 30% portion of total $CO_2$ emissions covers also in the commercial buildings and residential houses sector. To cope with efficiently this energy sinuation in building sector, Building microgrid or building tooling, heating & power(BCHP) system has been interested in recent day due to meeting thermal and electric energy requirements efficiently and with appropriate energy quality. A multi agent system is a collective of intelligent agents that communicate with each other and work cooperatively to achieve common goals. Also, it is to medicate and coordinate communication between Control Areas and Security Coordinators for teal-time control of the BCHP system and the power pid. In this new circumstance, it is very important to integrate the power and energy delivery system and the information system(communication, networks, and intelligent equipment) that controls it. Therefore, development of smart control modules with open communication protocol and seamlessly interchange the data and information between control network and data network including extranet and intranet give a great meanings. We designed and developed the TCP/IP-CAN IED agent modules and ModBus./LonTalk/(TCP/IP) IED agent ones to configure the multi-agent system based smart energy network of commercial buildings and also intelligent algorithms for inverter fault diagnostics which ran be operated in control level or agent level network.

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Risk Assessment of Fire and Explosion of Methane (메탄의 화재 및 폭발 위험성 평가)

  • Ha Dong-Myeong
    • Journal of the Korean Institute of Gas
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    • v.9 no.2 s.27
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    • pp.1-7
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    • 2005
  • The thermochemical parameters for safe handling, storage, transport, operation and process design of flammable substances are explosive limit, flash point, autoignition temperature, minimum oxygen concentration, heat of combustion etc.. Explosive limit and autoignition temperature are the major physical properties used to determine the fire and explosion hazards of the flammable substances. Explosive limit and autoignition temperature of methane fur LNG process safety were investigated. By using the literatures data, the lower and upper explosive limits of methane recommended 4.8 vol$\%$ and 16 vol$\%$, respectively. Also autoignition temperatures of methane with ignition sources recommended $540^{\circ}C$ at the electrically heated cruicible furnace (the whole surface heating) and recommended about $1000^{\circ}C$ in the local hot surface. The new equations for predicting the temperature dependence and the pressure dependence of the lower explosive limits for methane are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

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An Analysis of Relationship between Carbon Emission and Urban Spatial Patterns (도시패턴과 탄소배출량의 관계 분석)

  • Kim, In-Hyun;Oh, Kyu-Shik;Jung, Seung-Hyun
    • Spatial Information Research
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    • v.19 no.1
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    • pp.61-72
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    • 2011
  • Greenhouses gas emission due to usage of fossil fuel has been known as one of the main causes of global warming. Fundamentally, greenhouse gas is a by-product of economic activity. Since majority of economic activity happens in an urban setting, a countermeasure in an urban setting is needed. Therefore, an analysis of relationship between carbon dioxide emission and urban form will be investigated for urban planning and management in the future. The purpose of this study is to analyze the relationship between carbon dioxide emission and urban spatial patterns, and suggesting an urban form with low carbon dioxide emission. In order to achieve this, first theoretical analysis was carried out on urban spatial patterns related to physical size, usage rate, and activity level. Secondly, Seoul's dam on electricity, natural gas, local heating, petroleum, and water usage and mapping a carbon dioxide emission map. Thirdly, relationship between carbon dioxide emission and urban spatial patterns are analyzed and urban spatial patterns that affects energy usage in urban setting was elucidated, and elicited implications on future directions on urban planning based on our analyses above.

Antioxidant and Anti-inflammatory Properties of Raw and Processed Fruits and Vegetables

  • Lee, Yuan Yee;Saba, Evelyn;Kim, Minki;Rhee, Man Hee;Kim, Hyun-Kyoung
    • Biomedical Science Letters
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    • v.24 no.3
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    • pp.196-205
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    • 2018
  • Reactive oxygen species (ROS) generated from metabolic reactions cause oxidative DNA damage, which results in oxidative tissue injury. Therefore, there is an increasing demand in the intake of high antioxidant sources in order to maintain a healthy environment in cells. In this study, we investigated the antioxidant and anti-inflammatory activities of Malus domestica (apple), Pyrus communis L. (pear), Daucus carota L. (carrot), Brassica oleracea var. (broccoli), Brassica oleracea var. capitata (cabbage), and Raphanus sativus L. (radish) obtained from the local market. Since these are common fruits and vegetables that are widely consumed, we aimed to investigate their beneficial properties, placing particular emphasis on their antioxidant and anti-inflammatory properties. The samples were processed via an indirect heating method and their properties were compared to their raw forms. Based on DPPH and ABTS assays, processed samples showed better antioxidant activities when compared to raw samples and processed pear samples exhibited the best antioxidant activity. The anti-inflammatory activities of the samples were also investigated in LPS-treated RAW 264.7 cells. mRNA expression of pro-inflammatory mediators and cytokines (iNOS, COX-2, $TNF-{\alpha}$, $IL-1{\beta}$, and IL-6) was assessed using RT-PCR. As expected, processed samples exhibited better iNOS inhibition when compared to their raw forms and processed broccoli and cabbage samples exhibited outstanding anti-inflammatory effects. The samples, up to 1 mg/mL concentration, did not exhibit cytotoxicity against RAW 264.7 cells as demonstrated by cell viability assays. Altogether, processed broccoli and cabbage samples exhibited the strongest anti-inflammatory properties.

A Numerical Study on the Internal Flow and Combustion Characteristics of the Catalytic Combustor for the 5kW MCFC Power system (5kW 급 MCFC 발전시스템 촉매연소기의 유동 및 연소 특성에 대한 수치적 연구)

  • Kim, Chong-Min;Lee, Youn-Wha;Kim, Man-Young;Kim, Hyung-Gon;Hong, Dong-Jin;Cho, Ju-Hyeong;Kim, Han-Seok;Ahn, Kook-Young
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.3049-3052
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    • 2008
  • MCFC(molten carbonate fuel cell) power generation system is prime candidate for the utilization of fossil based fuels to generate ultra clean power with a high efficiency. In the MCFC power plant system, a combustor performs a role to supply high temperature mixture gases for cathode and heat for reformer by using the stack off-gas of the anode which includes a high concentration of $H_2O$ and $CO_2$. Since a combustor needs to be operated in a very lean condition and to avoid excessive local heating, catalytic combustor is usually used. The catalytic combustion is accomplished by the catalytic chemical reaction between fuel and oxidizer at catalyst surface, different from conventional combustion. In this study, a mathematical model for the prediction of internal flow and catalytic combustion characteristics in the catalytic combustor adopted in the MCFC power plant system is suggested by using the numerical methods. The numerical simulation models are then implemented into the commercial CFD code. After verifying result by comparing with the experimental data and calibrated kinetic parameters of catalytic combustion reaction, a numerical simulation is performed to investigate the variation of flow and combustion characteristics by changing such various parameters as inlet configuration and inlet temperature. The result show that the catalytic combustion can be effectively improved for most of the case by using the perforated plate and subsequent stable catalytic combustion is expected.

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A New Dynamic VRF Heat Hump Simulation Including Frosting and Defrosting Models (착상 및 제상을 포함한 VRF 히트펌프의 동적 수치해석 모델)

  • Park, Noma;Shin, Jeong Seob;Chung, Baik Young;Kim, Byung Soon
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.1
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    • pp.1-13
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    • 2015
  • In this study, a new dynamic VRF-type heat pump simulation model is proposed which incorporates frosting and defrosting models. Toward this end, a simple frosting model based on the perfect analogy, and lumped system based defrost model, are proposed. Then, frosting and defrosting models are incorporated into a dynamic heat pump model which adopts segment-by-segment local heat exchanger model and map-based variable speed compressor model. Thus, the model can naturally represent locally uneven frosting and defrosting on the heat exchanger surface. Developed simulation model is validated against available experimental data to show good agreement within 10% error for capacity and COP. Finally, developed dynamic heat pump model is applied to annual heating season simulation to show that seasonal COP of heat pump is degraded by 7% due to frosting and defrosting.

Crystal Chemistry and Paragenesis of Aluminum Sulphates from Mudstones of the Yeonil Group (I): basaluminite, hydrbasaluminite, and metabasaluminite (연일층군 이암에서 산출되는 알루미늄 황산염 광물의 결정화학 및 생성 (I): 배사알루미나팅, 하이드로베사알루미나이트 및 메타배사알루미나이트)

  • 노진환
    • Journal of the Mineralogical Society of Korea
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    • v.11 no.1
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    • pp.1-12
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    • 1998
  • In Pohang area, basaluminite accompanying a little amounts of hydrobasalumnite, super-genetically occurs as whitish cryptocrystalline (2-4 $\mu\textrm{m}$) clay-like aggregates in the vicinity of altered carbonate concretions embedded within mudstones of the Tertiary Yeonil Group. A hydrobasaluminite changed readily into a basaluminite at room temperature in air, and, in turn, into a metabasaluminite when heating to 150$^{\circ}$~30$0^{\circ}C$. For the basaluminite, a monoclinic unit-cellparameters (a=14.845$\AA$, b=10.006$\AA$, c=11.082$\AA$, $\beta$=122.15$^{\circ}$) were calculated by X-ray powder diffraction data. Its basal reflections (001 and 002) are XRD analyses strongly indicate that the aluminum sulphate mineral has a layer structure and, at least, three types of water, i.e., (1) interlayer water (9.0 wt %), (2) crystal water (8.0 wt %), and (3) structural water (19.0 wt %). may present in its lattice. Based on TG-DTG data combined with EDS and IR analyses, a new chemical formula of Al5SO4(OH)134H2O was given to the basaluminite. Field occurrence and stable isotope data ($\delta$18O, $\delta$D, $\delta$34S) for the basaluminite seem to reflect that it was formed by the leached meteoric solution from surrounding mudstones during or after uplifting. An interaction of the acid solution with carbonate concretion and the resultant local neutralization of the fluid rich in Al3+ and SO42- are major controls on the basaluminite formation.

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Examination on the Mounting Status of Cigar Lighter Receptacle for Vehicles and Analysis of its Tracking Characteristics (차량용 시가 잭의 장착 실태조사 및 트레킹 특성 분석)

  • Choi, Chung-Seog
    • Journal of the Korean Society of Safety
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    • v.24 no.4
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    • pp.28-33
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    • 2009
  • This study examined the mounting status of cigar lighter receptacles for vehicles and analyzed the tracking phenomenon that occurs when foreign material entered a cigar lighter receptacle to obtain data for the analysis of accident investigation. Regardless of the vehicle's output, cigar lighter receptacles are mounted in a vehicle horizontally, vertically, or at tilting or inclined angle. The tilting type cigar lighter receptacle is much easier to use but current leakage resulting from foreign materials (coffee, beverages, water, etc.) falling into the cigar lighter receptacle may cause a fire to start. This study used a vehicle battery (DC 12V) as a power supply for the tracking test and configured its circuit in the same way as that of an electrical device in a vehicle. The tracking phenomenon that occurred in the standby mode of the vehicle exhibited a fine flame and an irregular occurrence of smoke. While this tracking phenomenon was occurring, the leakage current and the reaching distance of the flame were measured to be approximately 930mA and $20{\sim}50cm$, respectively. It is thought that the resultant flame may ignite toluene, dust, cigarettes, etc. It was observed that as the tracking progressed, the internal metal socket melted and a hole was created, the surface of which was also severely carbonized. In addition, the electrical resistance of the carbonized conductive path was measured to be approximately $30{\Omega}$. It is thought that this much resistance may cause local heating when leakage current flows and could ignite any nearby flammable material.

Investigation of Combustion Properties for Using Safe Hydrogen (안전한 수소 이용을 위한 연소특성치 고찰)

  • Ha, Dong-Myeong
    • Journal of the Korean Institute of Gas
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    • v.12 no.2
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    • pp.1-6
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    • 2008
  • For the safety design and operation of many gas process, it is necessary to know certain explosion limit, flash point, autoignition temperature (AIT) and minimum oxygen concentration of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. In this study for the safe handling of hydrogen, explosion limit and AIT of combustion properties for hydrogen were investigated. By using the literatures data, the lower and upper explosion limits of hydrogen recommended 4.0 vol% and 77.0 vol%. Also the AIT of hydrogen with ignition sources recommended $400^{\circ}C$ at the electrically heated crucible furnace (the whole surface heating) and recommended $640^{\circ}C$ at the local hot surface. The new equations for predicting the temperature and the pressure dependence of the explosion limits of hydrogen are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

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