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A Study on safety against a fire of charging cable for mobile phone for vehicle (자동차용 모바일 폰 충전 케이블의 발화 안전성에 관한 연구)

  • Kwon, Jin-Wook;Choi, Kyu-Sik;Hwang, Myung-Whan
    • Journal of the Korea Safety Management & Science
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    • v.20 no.3
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    • pp.21-26
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    • 2018
  • This paper describes result of a study on safety against a fire of charging cable for mobile phone for vehicle. Combustion on the USB cable in the car was happened while driving. Gas coming from the burning USB cable could be a reason which can make a secondary car accident since the driver also can be embarrassed while driving. In order to prevent a secondary car accident connected on the road, to research a reason why USB cable can emit gas and be burned in charging. We did simulation test with abnormal fault condition for the electronic component on the board in the USB cable. So we get the result from abnormal fault condition simulation test, for instance, shorted test for output terminal of 8 pin switch, shorted test for chip resistor after thermal aging in the condition $25^{\circ}C$, 93 % RH during 48 hours. To analysis the result of all test, Combustion on the USB cable was not the 8 pin but other electrical component such as a chip resistor. Therefore we guess that the reason for USB cable combustion in charging in a car was not 8 pin and a LED but another defective component.

Evaluation of the Normalized Burn Ratio (NBR) for Mapping Burn Severity Base on IKONOS-Images (IKONOS 화상 기반의 산불피해등급도 작성을 위한 정규산불피해비율(NBR) 평가)

  • Kim, Choen
    • Korean Journal of Remote Sensing
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    • v.24 no.2
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    • pp.195-203
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    • 2008
  • Burn severity is an important role for rehabilitation of burned forest area. This factor led to the pilot study to determine if high resolution IKONOS images could be used to classify and delinenate the bum severity over burned areas of Samchock Fire and Cheongyang-Yesan Fire. The results of this study can be summarized as follows: 1. The modified Normalized Bum Ratio (NBR) for IKONOS imagery can be evaluated using burn severity mapping. 2. IKONOS-derived NBR imagery could provide fire scar and detail mapping of burned areas at Samchock fire and Cheongyang-Yesan Burns.

Changes of Landscape Pattern and Vegetation Structure in Rural Areal Area Disturbed by Fire (산불지역에서 경관유형과 식생구조의 변화)

  • 이창석;홍선기
    • The Korean Journal of Ecology
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    • v.21 no.4
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    • pp.389-399
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    • 1998
  • this study was focused on the effects of fire on spatial change of vegetation landscape in rural region. Fire types recognized as erown fire, severe surface fire and light surface fire in order of increasing intensity were described in a fire map. GIS was introduced to understand the relationship between fire types and topographic conditions or vegetation types. We also investigated land-use type and regeneration strategies after burning. Fire intensity depended on topographic conditions and vegetation types. Special land-use type in this area was collection of edible mushroom (Tricholoma matsutake). Mushrooms had been obtained from Pinus densiflora forests existing as edaphic climax or managed artificially. Regeneration strategy in burned areas was to make sprouts from burned oak stumps. A higher density and growth rate of sprouts, as compared to those on unburned areas, facilitated vegetation succession from P. densiflora forest to oak forest and consequently led to change of landscape pattern.

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72[W] Power LED Photovoltaic Lighting System including the Current Limiting Function (전류제한 기능을 갖는 72[W ]급 파워 LED 태양광 보안등)

  • Park, Hyo-Sik;Han, Woo-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.8
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    • pp.2999-3004
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    • 2010
  • In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. As power LED for lighting system can be burned out by heat problem, the driving current of power LED has to be controlled below the designed value. In this paper, power LED photovoltaic lighting system, which has the current limitting function, has been described. After photovoltaic power is generated from PV panel. it is charged into a battery. And then, after the charged power is converted to DC24[V] through a boost DC-DC converter, it is supplied to power LED at night. It has been validated by designing and testing of 72[W] power LED lighting system, which includes a PV charger, a boost DC-DC converter and a current limiter for driving power LED.

A Study on Winter-Covered Optical Satellite Imagery for Post-Eire Forest Monitoring

  • Kim, Choen;Park, Seung-Hwan
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.274-274
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    • 2002
  • Damage to forest trees, caused by wildfire, changes their spectral reflectance signature. This factor led to the initiation of a research project at the Remote Sensing & GIS Laboratory, Kookmin University, to determine if multispectral data acquired by IKONOS could provide fire scar and bum severity mapping. This paper will present detail mapping of burned areas in the eastern coast of Korea with IKONOS imagery. In addition, a single post-burn Landsat-7 ETM+ data was used to compare with IKONOS, the study area. Burn severity map based on IKONOS image was found to be affected by strong topographic illumination effects in the mountain forest. But it has better the delineation of the bum-scarred area. In this study the NDVI was analyzed for geometric illumination conditions influenced by topography(slop, aspect and elevation) and shadow(solar elevation and azimuth angle).

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Bioenergy Crop Production and Research Trends (바이오에너지 원료작물 생산 및 연구동향)

  • Kim, Kwang-Soo;Kim, Young-Bum;Jang, Young-Seok;Bang, Jin-Ki
    • Journal of Plant Biotechnology
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    • v.34 no.2
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    • pp.103-109
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    • 2007
  • The increasing industrialization of the world has led to precipitous rise for the demand of petroleum-based fuels. The world is presently confronted with the twin crises of fossil fuel depletion and environmental pollution. The search for alternative fuels, which promise a harmonious correlation with sustainable development, energy conservation, efficiency and environmental preservation, has become highly pronounced in the present. Bioenergy is playing an increasingly important role as an alternative and renewable source of energy. Use of Bioenergy has several potential environmental advantages. The most important perhaps is reduction in life cycle greenhouse gases emissions relatives petroleum fuels, since bioenergy is derived from plants which convert Carbon dioxide ($CO_{2}$) into Carbohydrates in their growth. Bioenergy includes solid biomass, biomas and liquid bio-fuels which are fuels derived from crop plants, and include biomass that's directly burned. The two most important bio liquid fuels today are bioethanol from fermenting grain, grass, straw or wood, and biodiesel from plant seed oil.

Control of Algal Blooms in Eutrophic Water Using Porous Dolomite Granules

  • Huh, Jae-Hoon;Choi, Young-Hoon;Lee, Shin Haeng;Cheong, Sun Hee;Ahn, Ji Whan
    • Journal of the Korean Ceramic Society
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    • v.54 no.2
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    • pp.108-113
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    • 2017
  • The use of aluminum-based coagulants in water pretreatment is being carefully considered because aluminum exposure is a risk factor for the onset of Alzheimer's disease. Lightly burned-dolomite kiln dust (LB-DKD) was evaluated as an alternative coagulant because it contains high levels of the healthful minerals calcium and magnesium. An organic pore forming agent (OPFA) was incorporated to prepare porous granules after OPFA removal through a thermal decomposition process. A spray drying method was used to produce uniform and reproducible spherical granules with low density, since fine dolomite particles have irregular agglomeration behavior in the hydration reaction. The use of fine dolomite powder and different porosity granules led to a visible color change in raw algae (RA) containing water, from dark green to transparent colorlessness. Also, dolomite powders and granules exhibited a mean removal efficiency of 48.3% in total nitrogen (T-N), a gradual increase in the removal efficiency of total phosphorus (T-P) as granule porosity increased. We demonstrate that porous dolomite granules can improve the settling time and water quality in summer seasons for the emergent treatment of excessive algal blooms in eutrophic water.

A Correlation among Work Environment, Job Engagement, and Burnout of Workers at a Community Children's Center Based on the JD-R Model (직무요구-자원모형을 적용한 지역아동센터 종사자의 업무환경, 직무열의, 직무소진 간 관련성)

  • Choi, Se-na;Park, Ji-Sun;Ryu, Han-Su
    • The Journal of the Korea Contents Association
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    • v.20 no.11
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    • pp.237-248
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    • 2020
  • This study investigates the effect of work environment-in terms of job demands and job resources-on worker job engagement and burnout based on the JD-R model. The aim is to provide preliminary data to formulate policy and practical measures to strengthen job engagement and prevent burnout of workers at a community children's center. To this end, a self-administered questionnaire was answered by 447 workers at such a center in the city of Daejeon, Korea, and the results were analyzed using SPSS 23.0 and AMOS 23.0. The research model had a statistically acceptable fit, with CFI = .900, TLI = .887, and RMSEA = .077. The following correlations were found among the key variables: i) a greater perceived amount of job resources led to a stronger worker job engagement but did not directly influence worker burnout; ii) more perceived job demands caused a higher worker burnout but did not directly influence worker job engagement; and iii) the greater the worker job engagement, the less burned out the workers were. These conclusions contribute to understanding the effect of the work environment on worker job engagement and burnout based on the JD-R model. We emphasize the need to improve this environment in community children's centers with supportive policy and practical measures to enhance worker job engagement and reduce burnout.

Study in the Development of Motion Recognition Tap-water using Ultrasonic Sensors (초음파 센서를 이용한 모션 인식 수도꼭지 개발 및 연구)

  • Kim, Dong-Hyun;Ryu, Jae-Hoo;Ju, Jong-Soo;Ahn, Jong-Pil;Kim, Jae-Wook
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.2
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    • pp.309-316
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    • 2022
  • Advances in technology have improved people's lives comfortably and have developed more easily, safely and simply. We usually turn on hot water to set the temperature of the water in the bathroom and gradually adjust the temperature to find the temperature we want with our skin. In this situation, I thought, "What if there is a device that can see the temperature of water with my eyes and help with the interior of the bathroom while including a safe system," and tried to create a system that values stability. For example, if a child accidentally changes the temperature of the water to high temperature while washing, he or she can get burned. And the biggest purpose is to secure better safety by adding LCDs and LEDs so that we can visually know the temperature before feeling it tactilely. As a result of the experiment, there was no error between the temperature detected by the water temperature sensor and the temperature displayed on the LCD, and no error occurred up to 27 cm in the distance measurement experiment using the ultrasonic sensor. There has been an error of about 2% since 28cm or older, but there is no significant inconvenience in using it within the category of faucets.

A Study on Perfuming Clothes and the Incense Trade of East Asia in Goryeo Dynasty (고려시대 동아시아 훈의(熏衣)문화와 향재의 교역 연구)

  • Ha, Sumin
    • Korean Journal of Heritage: History & Science
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    • v.53 no.2
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    • pp.204-221
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    • 2020
  • East Asian countries share a culture of perfuming clothes. The prosperity of the Maritime Silk Road and the incense trade are direct factors that have led to the development of incense culture. Perfuming clothes is a method of applying fragrance by burning incense. The Chinese could make an incense mixture with various types of incense, and records demonstrating use of perfuming clothes tools (熏籠) show that they might have perfumed clothes with incense mixtures. During the Tang dynasty, the incense trade thrived. Examples of ancient literature such as 『千金要方』, 『香譜』, 『香乘』 describe how to make incense for perfuming clothes and how to perfume clothes. 『桂海虞衡志』 and 『諸蕃志』 shows trade partners and goods. Incense was introduced to Korea alongside Buddhist culture. 『買新羅物解』 shows Silla traded incense with Japan. One of the trade goods recorded in 『買新羅物解』 is perfuming cloth incense (熏衣香), which establishes that Silla performed perfuming clothes at that time. During the Goryeo dynasty, Goryeo exported musk as well as ginseng. The royal family burned incense from the Song royal family. Noblewomen preferred sachets. The use of this dress continued into the Joseon dynasty. 『買新羅物解』 showed that Japan imported incense from Silla. 『The tale of Genji』 illustrates Heian nobles' incense culture, perfuming clothes culture, and trade of incense. Perfuming clothes tools became essential articles for marriage purposes and it developed in a practical shape. The Champa had a perfuming clothes culture. It is described on 『諸蕃志』. As Agilawood is found in Tongking, and Tongking was neighbor to the Champa and China, they might have had a perfuming clothes culture as well. Korea, China, Japan, and Vietnam shared a perfuming clothes culture. We can identify universality and commonality in the purpose of perfuming clothes, time of development, the method of making the incense mixture for perfuming clothes, the method of perfuming clothes, the tools, the gender of perfumer, and the type of herbs and spices.