• 조명전기설비학회논문지
• /
• 제25권4호
• /
• pp.104-110
• /
• 2011

There are over 30[%] of electric fires in Korea happened at wire or wiring devices. For its prevention many safety devices are set up electric equipments. These safety devices are not working in a rated current's condition of electric equipment. But when wire is partially disconnected, electric fire is able to be happened even though current is smaller than a rated current value. This paper studied thermal characteristics and fire ability when wire in plug is partially disconnected. The experiment is progressed a method that inner wire of plug is partially disconnected and after that current that is less than a rated current is flowed. As the result, heating occurred in near of partially disconnected wire makes that outer sheath is melted, plug cover is carbonized, and even sometimes wire is fused. And results of analysis of thermal image of partially disconnected wire happened in plug, it shows a difference to heating distribution and temperature appeared surface of plug depend on a progress of a partially disconnected wire.

• Journal of Biosystems Engineering
• /
• 제34권1호
• /
• pp.44-49
• /
• 2009

This study was conducted to investigate the pyrolysis characteristics of switchgrass using TGA-FTIR instrument. Switchgrass is a high yielding perennial grass that has been designated as a potential energy crop, because of its high energy value. Ground switchgrass were pyrolysed at different heating rates of 10, 20, 30, and $40^{\circ}C/min$ in a TGA-FTIR instrument. The thermal decomposition characteristics of switchgrass were analyzed, and the gases volatilized during the experiment were identified. The thermal decomposition of switchgrass started at approximately $220^{\circ}C$, followed by a major loss of weight, where the main volatilization occurred, and the thermal decomposition was essentially completed by $430^{\circ}C$. The pyrolysis process was found to compose of four stages; moisture evaporation, hemicellulose decomposition, cellulose decomposition, and lignin degradation. The peak temperatures for hemicellulose decomposition ($306^{\circ}C$ to $327^{\circ}C$) and cellulose decomposition ($351^{\circ}C$ to $369^{\circ}C$) were increased with greater heating rates. FTIR analysis showed that the following gases were released during the pyrolysis of switchgrass; $CO_2$, CO, $CH_4$, $NH_3$, COS, $C_{2}H_{4}$, and some acetic acid. The most gas species were released at low temperature from 310 to $380^{\circ}C$, which was corresponding well with the observation of thermal decomposition.

• 에너지공학
• /
• 제20권2호
• /
• pp.96-102
• /
• 2011

본 논문은 2차원 충돌제트 시스템에서 충돌판이 천이영역에 위치할때, 열전달성능이 감소하는 벽면분류영역의 열전달증진을 목적으로 난류촉진체인 정 4각 로드를 평판전열면 앞에 설치하고 로드와 로드사이의 피치(P)를 40 mm로 고정한 후 로드의 폭(W) 변화(4, 6, 8 mm) 및 로드와 전열면사이의 간극(C) 변화(1, 2, 4, 6 mm)에 따른 유동특성과 열전달특성에 대해 실험을 수행하고, 그 결과를 수치해석과 비교 검토하였다. 또한 로드가 설치되지 않은 경우와 정량적으로 비교하여 충돌제트 시스템에서 난류촉진체를 이용한 열전달증진에 관한 기초적 자료를 제공하고자 한다.

• 한국안전학회지
• /
• 제17권2호
• /
• pp.39-44
• /
• 2002

This study was investigated the thermal decomposition characteristics of azo type sponge blowing agent azodicarbonamide(ADCA) using differential scanning calorimeter(DSC). The experimental results showed that the exothermic onset $temperatures(T_{o})$ for ADCA were about $201{\sim}206^{\circ}C$ and evolution heats(Q) were about $144{\sim}150cal/g$. The exothermic onset $temperatures(T_{o})$, exothermic maximum $temperature(T_{m})$ and exothermic final $temperature(T_{f})$ were decreased by decreasing particle size of ADCA and evolution heats(Q) were increased with it. $T_{o}$ and Q for $6.1{\sim}7.2{\mu}m$ ADCA were increased by increasing heating rate at constant sample weight and activation energy was about 37.29kcal/mol. A positive gas pressure was employed in the elucidation of the decomposition behavior of ADCA because it sublimes during linear heating at atmospheric pressure. $T_{o}$ and Q of ADCA tended to increase with a pressure in air or nitrogen. In the case of azo dye, experimental results showed that $T_{o}$ were about $280{\sim}420^{\circ}C$ and Q were about $2{\sim}30cal/g$.

• Journal of Applied Biological Chemistry
• /
• 제56권2호
• /
• pp.79-81
• /
• 2013

맹종죽(Phyllostachys pubescens) 수액의 저장성을 향상시키기 위하여 열처리 조건을 조사하였다. 수액을 $70^{\circ}C$에서 30분간 열처리한 후 $2^{\circ}C$에서 보관하면서 수액의 pH, 총 세균수, 관능특성을 경시적으로 분석하여 품질변화를 조사하였다. 그 결과, 맹종죽 수액의 품질 및 관능특성이 10일 동안 유지되었다.

• 설비공학논문집
• /
• 제17권1호
• /
• pp.82-87
• /
• 2005

The purpose of this study is to suggest the characteristics and actual state of energy consumption by the analysis of energy consumption data in an office building. This study examines and analyzes daily and monthly energy consumption of an office building located in Seoul, Korea regarding type of load and business classification within a building. The results are as follows. 1) Energy consumption of office building for each type of load show similar consumption patterns, regardless of seasons such as cooling period and heating period. 2) Out of all annual energy consumption, consumption for lighting took about $43\;\%,$ general electric Power about $23\;\%,$ emergency power $25\;\%,$ computer center $5\;\%$ and cooling power $4\;\%,$ showing that the consumption for lighting was highest, and the percentage of energy consumption for cooling power for operation of cooling facilities took the lowest percentage. 3) Annual gas consumption used for heating and hot water supply were $38,\;36\;\%$ for officetel and office respectively, and $26\;\%$ for arcade. 4) Electricity consumptions used for cooling power for each use of building, office and officetel recorded in July and August of cooling seasons. Even though it shows different patterns for each month, energy consumption showed unique pattern throughout the cooling seasons.

• 한국태양에너지학회 논문집
• /
• 제21권2호
• /
• pp.27-34
• /
• 2001

The greenhouse heating system using solar energy has been realized in the protective agriculture in this study in order to analyse the thermal energy characteristics of the system the effects of ambient air temperature, solar radiation, relative humidities and water content of ambient air on the greenhouse air temperature were investigated through computer simulation experimental analysis for validation of the simulation. The results from this study are summarized as follows: 1) The expected values of inside air temperature for the system solar energy were very much close to the experimental values. 2) In the system using solar energy, the expected values of daytime surface temperature of soil by computer simulation were very much similar to the measured values, but those of nighttime were higher than the measured value by almost $2.5^{\circ}C$. 3) Heat loss of daytime was found to be larger than that of night time as much as 2.0 to 4.2 times for the system using solar energy. 4) In the system using solar energy. while the ambient air temperature varied between $-7^{\circ}C$ and $-3.8^{\circ}C$, the temperature of the inside air was maintained between $0^{\circ}C$ and $22^{\circ}C$. 5) At the minimum ambient temperature of $-7^{\circ}C$, the temperature of the inside air was $0^{\circ}C$.

• KIEAE Journal
• /
• 제16권6호
• /
• pp.143-149
• /
• 2016

Purpose: This study is to analyze the characteristics of energy usage in apartment houses that had built for 20 years recently in capital area and the correlation between the characteristics of energy usage and the regulation of energy efficiency in building. Method: It is investigated 264 apartment sites having been built since 1991 where 312,071 houses live. The sites were listed on Naver map. Quantities of energy usages in the sites were searched in a portal, Green Together being operated by the Ministry of Land, Infrastructure and Transport. The appraisal report of building energy in the portal is recording usage quantity of gas energy, district cooling & heating energy, electric energy, total energy, 1st gas energy, 1st district cooling & heating energy, 1st electric energy, 1st total energy, etc. Result: Analyzing the average of total energy usage from 1991 to 2012, the average in 2001, 2008 each was reduced more than 10 percent compared to the previous year. It was analyzed that the reduction was relevant to building energy-saving design criterion which have been tightened more than before.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1989년도 춘계학술대회 논문집
• /
• pp.43-46
• /
• 1989

Epoxy, noticed as a new insulation material for electrical equipments, may become an excellent cured material from the crosslink reaction with some curing agents and accelerators. The characteristics of cured epoxy is determined by the method of lattice formation according to curing method. The purpose of this paper, varing the process of lattice formation by various surrounding temperatures and heating time during the curing process, is to obtain the optimum cured condition for electrical insulation from the results of investigation on the physical and dielectric properties of cured epoxy. In this investigation, it is found that the excessive temperature and heating time brings on the growth of metamorphic methyl and the insulating properties of cured epoxy is decreased by this phenomenon. As a result, it is concluded that the optimum dielectric characteristics can be obtained when cured at a curing temperature at 14$0^{\circ}C$ for one hour.

• Journal of Mechanical Science and Technology
• /
• 제16권2호
• /
• pp.219-226
• /
• 2002

Natural gas is considered to be a promising alternative fuel for passenger cars, truck transportation and stationary engines providing positive effects both on the environment and energy security. However, since the composition of natural gas fuel varies with location, climate and other factors, it is anticipated that such changes in fuel properties will affect emission characteristics and performance of CNG (Compressed Natural Gas) engines. The purpose of the present study is to investigate the effects of the difference in gas composition on the engine performance and emission characteristics. The results show that THC (Total Hydrocarbon) decreases with increasing Wl (Wobbe Index) and MCP (Maximum Combustion Potential). On the other hand, it is observed that NOx slightly increases as Wl and MCP increase. The TLHV (Total Lower Heating Value of Intake) is proposed in this study as a potential index for compatibility of gas fuels in a CNG engine. There is a variation in power up to 20% depending on the composition of gas when the A/F ratio and spark timing are flexed for a specific gas fuel.